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Sample records for acinetobacter calcoaceticus phea-2

  1. 21 CFR 866.3010 - Acinetobacter calcoaceticus serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Acinetobacter calcoaceticus serological reagents... Acinetobacter calcoaceticus serological reagents. (a) Identification. Acinetobacter calcoaceticus serological reagents are devices that consist of Acinetobacter calcoaceticus antigens and antisera used to...

  2. Ribotyping of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.

    OpenAIRE

    Gerner-Smidt, P

    1992-01-01

    The Acinetobacter calcoaceticus-Acinetobacter baumannii complex consists of four genotypically distinct but phenotypically very similar bacterial species or DNA groups: A. calcoaceticus (DNA group 1), A. baumannii (DNA group 2), unnamed DNA group 3 (P. J. M. Bouvet and P. A. D. Grimont, Int. J. Syst. Bacteriol. 36:228-240, 1986), and unnamed DNA group 13 (I. Tjernberg and J. Ursing, APMIS 97:595-605, 1989). Because strains in this complex cause nosocomial outbreaks, it is important to be able...

  3. gyrB Multiplex PCR To Differentiate between Acinetobacter calcoaceticus and Acinetobacter Genomic Species 3 ▿

    OpenAIRE

    Higgins, Paul G.; Lehmann, Marlene; Wisplinghoff, Hilmar; Seifert, Harald

    2010-01-01

    A previously established multiplex PCR that identifies to the species level Acinetobacter baumannii and Acinetobacter genomic species 13TU (GS13TU) was expanded to include Acinetobacter calcoaceticus and Acinetobacter genomic species 3.

  4. Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

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    Chin-Soon Chee

    2014-01-01

    Full Text Available Glutathione transferases (GST were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW of 23 kDa. 2-dimensional (2-D gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5 and GST2 (pI 6.2 with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase and F0KKB0 (glutathione S-transferase III of Acinetobacter calcoaceticus strain PHEA-2, respectively.

  5. Characterization of affinity-purified isoforms of Acinetobacter calcoaceticus Y1 glutathione transferases.

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    Chee, Chin-Soon; Tan, Irene Kit-Ping; Alias, Zazali

    2014-01-01

    Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) of Acinetobacter calcoaceticus strain PHEA-2, respectively.

  6. [Degradation of oil derivatives by Acinetobacter calcoaceticus MM5].

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    Marín, M M; Ortiz, M L; Laborda, F

    1994-01-01

    This paper describes the isolation of microorganisms from polluted heating oil. The growth of one of them has been studied (Acinetobacter calcoaceticus MM5) in several linear and branched hydrocarbons as well as the effect of its growth on commercial diesel oil. Acinetobacter calcoaceticus MM5 is not capable of using glucose as its only source of carbon, and it needs the presence of nitrogen and phosphorus sources to degrade any petroleum by-product.

  7. First report of Oxa-72-producing Acinetobacter calcoaceticus in Lebanon

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    A. Al Atrouni

    2016-01-01

    Full Text Available Emergence of carbapenem-resistant Acinetobacter spp. has been increasingly reported worldwide. We report here the first detection of an Acinetobacter calcoaceticus isolate from vegetables in Lebanon carrying the blaOxa-72 gene. These findings show that the Lebanese environment may constitute a potential reservoir for this antibiotic resistance gene.

  8. Prosthetic valve endocarditis caused by Acinetobacter calcoaceticus subsp. lwoffi.

    OpenAIRE

    Weinberger, I. (Ingeburg); Davidson, E.; Rotenberg, Z; Fuchs, J; Agmon, J

    1987-01-01

    Acinetobacter spp. are uncommon etiologic agents of prosthetic valve endocarditis. Two patients with Acinetobacter calcoaceticus subsp. lwoffi prosthetic valve endocarditis are described. The patients were successfully treated with antibiotics (cefotaxime sodium and gentamicin sulfate); thus, we suggest medical treatment rather than early valve replacement in this particular type of infection.

  9. Longitudinal Characterization of Acinetobacter baumannii-calcoaceticus Complex, Klebsiella pneumoniae, and Methicillin-Resistant Staphylococcus aureus Colonizing and Infecting Combat Casualties

    Science.gov (United States)

    2012-01-01

    Brief report Longitudinal characterization of Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin-resistant...resistant Acinetobacter baumannii-calcoaceticus complex Klebsiella pneumoniae Methicillin-resistant Staphylococcus aureus MRSA Drug-resistant...Acinetobacter baumannii-calcoaceticus complex, Klebsiella pneumoniae , and methicillin- resistant Staphylococcus aureus colonize and infect combat casualties

  10. Species identification within Acinetobacter calcoaceticus-baumannii complex using MALDI-TOF MS.

    Science.gov (United States)

    Toh, Benjamin E W; Paterson, David L; Kamolvit, Witchuda; Zowawi, Hosam; Kvaskoff, David; Sidjabat, Hanna; Wailan, Alexander; Peleg, Anton Y; Huber, Charlotte A

    2015-11-01

    Acinetobacter baumannii, one of the more clinically relevant species in the Acinetobacter genus is well known to be multi-drug resistant and associated with bacteremia, urinary tract infection, pneumonia, wound infection and meningitis. However, it cannot be differentiated from closely related species such as Acinetobacter calcoaceticus, Acinetobacter pittii and Acinetobacter nosocomialis by most phenotypic tests and can only be differentiated by specific, time consuming genotypic tests with very limited use in clinical microbiological laboratories. As a result, these species are grouped into the A. calcoaceticus-A. baumannii (Acb) complex. Herein we investigated the mass spectra of 73 Acinetobacter spp., representing ten different species, using an AB SCIEX 5800 MALDI-TOF MS to differentiate members of the Acinetobacter genus, including the species of the Acb complex. RpoB gene sequencing, 16S rRNA sequencing, and gyrB multiplex PCR were also evaluated as orthogonal methods to identify the organisms used in this study. We found that whilst 16S rRNA and rpoB gene sequencing could not differentiate A. pittii or A. calcoaceticus, they can be differentiated using gyrB multiplex PCR and MALDI-TOF MS. All ten Acinetobacter species investigated could be differentiated by their MALDI-TOF mass spectra.

  11. Biosurfactants from Acinetobacter calcoaceticus BU03 enhance the solubility and biodegradation of phenanthrene.

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    Zhao, Zhenyong; Wong, Jonathan W C

    2009-03-01

    A thermophilic bacterial strain, Acinetobacter calcoaceticus BU03, with a biosurfactant-producing capability, was isolated from petroleum-contaminated soil with an improved procedure which employed the solubilization of polycyclic aromatic hydrocarbons (PAHs), i.e. naphthalene in agar plate, as a selection criterion. Crude biosurfactant was recovered from the culture of BU03 by extraction with n-hexane, and its properties were investigated. Biosurfactants from A. calcoaceticus BU03 constitute a thermo-stable mixture, composed of different agents with surface activities. At their critical micelle concentration (CMC) of 152.4 mg L(-1), the crude biosurfactants produced from A. calcoaceticus BU03 decreased the air-water surface tension to 38.4 mN m(-1). In thermophilic conditions, the emulsifying activity is 2.8 times that of Tween 80. The effects of the biosurfactants produced by A. calcoaceticus on the solubility and biodegradation of PAHs were investigated in batch systems. Biosurfactants produced by A. calcoaceticus BU03 at 25 times their CMC significantly increased the apparent aqueous solubility of phenanthrene (PHE), pyrene (PYR) and benzo(a)pyrene (B[a]P) to 54.3, 6.33 and 2.08 mg L(-1), respectively. In aqueous system, the biosurfactants at concentrations of 0.5 CMC and 1 CMC slightly enhanced the biodegradation of PHE by a consortium of PAH-degrading microrganisms. Results indicate that biosurfactants from A. calcoaceticus BU03 have potential to enhance the removal of PAHs from contaminated sites.

  12. Siderophoregenic Acinetobacter calcoaceticus Isolated From Wheat Rhizosphere With Strong PGPR Activity

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    Chaudhari Bhushan, L.

    2009-01-01

    Full Text Available Thirty-two bacterial isolates were obtained from wheat rhizosphere in black cotton soils of North Maharashtra region and subsequently tested for in-vitro siderophore production. Wheat isolate SCW1, being a strong siderophore producer, was selected, identified and confirmed as Acinetobacter calcoaceticus. The strain produced catechol type of siderophores during exponential phase which was influenced by iron content of medium. Seed bacterization with siderophoregenic A. calcoaceticus improved plant growth in pot and field studies. Such PGPR activity was attributed to the ability of strain to solubilise phosphates and produce IAA. Siderophore mediated antagonism was observed against common phytopathogens viz., Aspergillus flavus, A. niger, Colletotrichum capsicum and Fusarium oxysporum.

  13. Genome Sequences of Four Acinetobacter baumannii-A. calcoaceticus Complex Isolates from Combat-Related Infections Sustained in the Middle East

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    2014-02-06

    baumannii -A. calcoaceticus Complex Isolates from Combat-Related Infections Sustained in the Middle East Acinetobacter baumannii is among the most...responses make treatment difficult. Here, we report the genome sequences of four clinical Acinetobacter baumannii - A. calcoaceticus complex isolates... Acinetobacter baumannii , A. calcoaceticus, combat-related infections REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S

  14. Acinetobacter seifertii sp. nov., a member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolated from human clinical specimens.

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    Nemec, Alexandr; Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Brisse, Sylvain; Higgins, Paul G

    2015-03-01

    This study aimed to define the taxonomic status of a phenetically distinct group of 16 strains that corresponds to Acinetobacter genomic species 'close to 13TU', a provisional genomic species of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex recognized by Gerner-Smidt and Tjernberg in 1993. These strains have been isolated in different countries since the early 1990s and were mostly recovered from human clinical specimens. They were compared with 45 reference strains representing the known taxa of the ACB complex using taxonomic methods relevant to the genus Acinetobacter. Based on sequence analysis of the concatenated partial sequences (2976 bp) of seven housekeeping genes, the 16 strains formed a tight and well-supported cluster (intracluster sequence identity of ≥98.4 %) that was clearly separated from the other members of the ACB complex (≤94.7 %). The species status of the group was supported by average nucleotide identity values of ≤91.7 % between the whole genome sequence of representative strain NIPH 973(T) (NCBI accession no. APOO00000000) and those of the other species. In addition, whole-cell matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) MS analyses indicated the distinctness of the group at the protein level. Metabolic and physiological tests revealed several typical features of the group, although they did not allow its reliable differentiation from the other members of the ACB complex. We conclude that the 16 strains represent a distinct novel species, for which we propose the name Acinetobacter seifertii sp. nov. The type strain is NIPH 973(T) ( = CIP 110471(T) = CCUG 34785(T) = CCM 8535(T)).

  15. Exocellular esterase and emulsan release from the cell surface of Acinetobacter calcoaceticus.

    OpenAIRE

    Shabtai, Y; Gutnick, D L

    1985-01-01

    An esterase activity has been found, both in the cell-free growth medium and on the cell surface of the hydrocarbon-degrading Acinetobacter calcoaceticus RAG-1. The enzyme catalyzed the hydrolysis of acetyl and other acyl groups from triglycerides and aryl and alkyl esters. Emulsan, the extracellular heteropolysaccharide bioemulsifier produced by strain RAG-1, was also a substrate for the enzyme. Gel filtration showed that the cell-free enzyme was released from the cell surface either emulsan...

  16. Production and characterization of bioemulsifier from a marine bacterium, Acinetobacter calcoaceticus subsp. anitratus SM7

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    Kulnaree Phetrong

    2008-05-01

    Full Text Available Marine bacterium strain SM7 was isolated as a bioemulsifier-producing bacterium from oil-spilled seawater in Songkhla lagoon, Thailand. It was identified as Acinetobacter calcoaceticus subsp. anitratus based on morphology, biochemicalcharacteristics and 16S rRNA sequence. A. calcoaceticus subsp. anitratus SM7 produced an extracellular emulsifying agent when grown in a minimal salt medium (pH 7.0 containing 0.3% (v/v n-heptadecane and 0.1% (w/v ammoniumhydrogen carbonate as carbon source and nitrogen source, respectively, at 30oC with agitation rate of 200 rpm. Crude bioemulsifier was recovered from the culture supernatant by ethanol precipitation with a yield of 2.94 g/l and had a criticalemulsifier concentration of 0.04 g/ml. The crude bioemulsifier was capable of emulsifying n-hexadecane in a broad pH range (6-12, temperatures (30-121oC and in the presence of NaCl up to 12% (w/v. The bioemulsifier was stable in saltsolution ranging from 0 to 0.1% (w/v of MgCl2 and CaCl2. The broad range of pH stability, thermostability and salt tolerance suggested that the bioemulsifier from A. calcoaceticus subsp. anitratus SM7 could be useful in environmentalapplication, especially bioremediation of oil-polluted seawater.

  17. Caracterização molecular e fenotípica de amostras bacterianas pertencentes ao complexo Acinetobacter calcoaceticus-Acinetobacter baumannii

    OpenAIRE

    Elizabeth Harummyy Takagi

    2011-01-01

    Nos últimos 30 anos, Acinetobacter tornou-se um dos patógenos de maior preocupação clínica pela falta de terapias eficazes em virtude do fenótipo de multirresistência frequentemente apresentado. Dentre as espécies do gênero Acinetobacter, A. baumannii, A. genoespécie 3 e A. genoespécie 13TU são as mais comumente encontradas a partir de amostras biológicas. Estas espécies ao lado de A. calcoaceticus constituem o complexo A. calcoaceticus-A. baumannii (ACB). Este estudo propõe um esquema compos...

  18. EMULSAN ANALYSIS PRODUCED BY LOCALLY ISOLATED BACTERIA AND ACINETOBACTER CALCOACETICUS RAG-1

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    P. Chamanrokh, M. Mazaheri Assadi, A. Noohi, S. Yahyai

    2008-04-01

    Full Text Available Growth of previously isolated bacteria from Iranian oil reservoirs on different carbon and energy sources and under varying conditions have been used to produce a class of extracellular microbial protein-associated lipopolysaccharides named emulsan.Several Bacteria were previously isolated from Iranian oil reservoirs and designated as; Ilam-1 and Paydar-4. In present study, the isolated strains were compared with standard sample of Acinetobacter calcoaceticus RAG-1 from Persian Type Culture Collection (PTCC 1641, IROST. Among the isolated strains, two strains were found to produce an extracellular, emulsifying agent when grown in Mineral Salt Medium containing soya oil, ethanol or local crude oil. The isolated bacteria were cultured and further analysed using protein estimation, reducing sugar analysis, hemolytic activity, surface tension and emulsification activity tests. The crude emulsifier of RAG-1, PAYDAR-4 and ILAM-1 were concentrated from the cell-free culture fluid by ammonium sulfate precipitation to yield 1.89g, 1.78g and 1.69g of bioemulsan respectively. Emulsifying activity was observed over the entire production process. These investigations showed that emulsan produced by isolated Iranian crude oil reservoir were comparable with Acinetobacter calcoaceticus RAG-1 which is made of carbohydrate backbone as its hydrophilic part (N-acetyl-D-galactoseamine, N-acetylgalactoseamine uronic acid, diamino-6-deoxy-D-glucose and fatty acid chain as its hydrophobic portion.

  19. Community-acquired necrotizing fasciitis caused by Acinetobacter calcoaceticus: a case report and literature review.

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    Nonaka, Yuko; Nagae, Masaaki; Omae, Takahito; Yamamoto, Shuhei; Horitani, Ryosuke; Maeda, Daigen; Yoshinaga, Takayuki

    2014-05-01

    A 61-year-old man presented with pain in the abdomen and right lower limb. He had a history of hepatitis B virus-induced liver cirrhosis, but had not been visiting the outpatient clinic and did not receive any medication. Cutaneous necrosis and bulla were observed on his abdomen and right lower limb. The necrotic skin was incised, and he was diagnosed with necrotizing fasciitis. A nonfermentative Gram-negative bacillus infection was confirmed from aspirated fluid and blood cultures. Therefore, meropenem and immunoglobulins were administered. Because necrosis was widespread, surgical debridement was performed. Thereafter, Acinetobacter calcoaceticus infection was confirmed by semi-quantitative PCR using the bullous fluid and blood cultures. Meropenem was administered for 3 weeks, followed by levofloxacin alone for 1 week. The patient's condition improved; therefore, skin grafting was performed as planned and yielded a favorable response. After rehabilitation, the patient could walk without support and infection did not recur. However, he had severe liver cirrhosis and large esophageal varices, and he eventually died from sudden varix rupture. Necrotizing fasciitis is an uncommon soft tissue infection, associated with high morbidity and mortality, and early recognition and treatment are crucial for survival. Acinetobacter is rarely associated with necrotizing fasciitis. Although this is a very rare case of the occurrence of necrotizing fasciitis due to A. calcoaceticus infection, we believe that this organism can be pathogenic in immunocompromised patients such as those with liver cirrhosis by reporting this case.

  20. PHYSICOCHEMICAL AND STRUCTURAL STUDIES ON ACINETOBACTER-CALCOACETICUS RAG-1 AND MR-481 - 2 STANDARD STRAINS IN HYDROPHOBICITY TESTS

    NARCIS (Netherlands)

    VANDERMEI, HC; COWAN, MM; BUSSCHER, HJ

    1991-01-01

    Acinetobacter calcoaceticus RAG-1 and MR-48 1, two standard strains used in microbial adhesion to hydrocarbons (MATH), were characterized by contact angles, pH-dependent zeta potentials, elemental surface composition by X-ray photoelectron spectroscopy (XPS), and molecular composition by infrared sp

  1. Risk factors for mortality in Acinetobacter calcoaceticus-baumannii bacteraemia

    Institute of Scientific and Technical Information of China (English)

    Asmita A Mehta; V Anil Kumar; Kumari Indira K; Suresh G Nair; Kavitha R Dinesh; Sanjeev K Singh

    2012-01-01

    Objective: To determine the risk factors associated with mortality in Acinetobacter calcoaceticus–baumannii (Acb) complex blood stream infection. Methods: This was an observational study conducted in tertiary care hospital of South India. All patients with blood culture positive for Acb complex from January 2008 to December 2009 were included and a standardized abstraction form was used to abstract data. P value was calculated by Chi square test. Univariate analysis was done by using 2x2 tables and the variables with P value of <0.1 were further subjected to multivariate analysis. Multivariate analysis was done by logistic regression method. Results: After excluding the polymicrobial infections and duplicate isolates from the same patients, 81 cases were included in our study. Out of 81 patients, 20 (24.6%) patients had positive isolate from body secretion other than blood for Acb complex, majority were hospitalized in intensive care unit (74%), had indwelling vascular catheters (68%) and were mechanically ventilated (61%). Multi drug resistant phenotypes were seen in 56 (69.1%) isolates and among them 13 (16%) were resistant to carbapenems. Univariate analysis showed renal disease, diabetes mellitus, use of mechanical ventilation and absence of appropriate antibiotic therapy, leucopenia, thrombocytopenia and raised prothrombin time were related to increased mortality in Acb complex bacteraemia. However, in multivariate analysis independent risk factors for mortality in Acb complex bacteraemia were platelets of less than 1.5 lacks and inappropriate empirical antibiotics. Conclusions: Thrombocytopenia and absence of appropriate antibiotics were risk factors associated with mortality in Acb bacteraemia. Patients with blood culture showing Acb complex bacteraemia with above findings should be attended with aggressive management. Clinician of hospitals with high incidence of Acb complex bacteraemia, should predict the chances of such infection even prior to blood

  2. Improvement of MALDI-TOF MS profiling for the differentiation of species within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.

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    Šedo, Ondrej; Nemec, Alexandr; Křížová, Lenka; Kačalová, Magdaléna; Zdráhal, Zbyněk

    2013-12-01

    MALDI-TOF MS is currently becoming the method of choice for rapid identification of bacterial species in routine diagnostics. Yet, this method suffers from the inability to differentiate reliably between some closely related bacterial species including those of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex, namely A. baumannii and Acinetobacter nosocomialis. In the present study, we evaluated a protocol which was different from that used in the Bruker Daltonics identification system (MALDI BioTyper) to improve species identification using a taxonomically precisely defined set of 105 strains representing the four validly named species of the ACB complex. The novel protocol is based on the change in matrix composition from alpha-cyano-4-hydroxycinnamic acid (saturated solution in water:acetonitrile:trifluoroacetic acid, 47.5:50:2.5, v/v) to ferulic acid (12.5mgml(-1) solution in water:acetonitrile:formic acid 50:33:17, v/v), while the other steps of sample processing remain unchanged. Compared to the standard protocol, the novel one extended the range of detected compounds towards higher molecular weight, produced signals with better mass resolution, and allowed the detection of species-specific signals. As a result, differentiation of A. nosocomialis and A. baumannii strains by cluster analysis was improved and 13 A. nosocomialis strains, assigned erroneously or ambiguously by using the standard protocol, were correctly identified.

  3. Improved homology model of cyclohexanone monooxygenase from Acinetobacter calcoaceticus based on multiple templates.

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    Bermúdez, Eduardo; Ventura, Oscar N; Eriksson, Leif A; Saenz-Méndez, Patricia

    2014-04-01

    A new homology model of cyclohexanone monooxygenase (CHMO) from Acinetobacter calcoaceticus is derived based on multiple templates, and in particular the crystal structure of CHMO from Rhodococcus sp. The derived model was fully evaluated, showing that the quality of the new structure was improved over previous models. Critically, the nicotinamide cofactor is included in the model for the first time. Analysis of several molecular dynamics snapshots of intermediates in the enzymatic mechanism led to a description of key residues for cofactor binding and intermediate stabilization during the reaction, in particular Arg327 and the well known conserved motif (FxGxxxHxxxW) in Baeyer-Villiger monooxygenases, in excellent agreement with known experimental and computational data.

  4. [The influence of Acinetobacter calcoaceticus K-4 surface-active substances on the efficiency of microbial destruction of oil pollutants].

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    Pyroh, T P; Antoniuk, S I; Sorokina, A I

    2009-01-01

    The possibility of the use of Acinetobacter calcoaceticus K-4 surface-active substances (SAS) for water purification from oil was shown. The efficiency of oil degradation (2.6 g/l) in the presence of SAS preparations (5-15 %) in the form of postfermentation of cultural liquid or its supernatant was established to be 81-95 %. Intensification of oil destruction was determined by SAS affecting the activity of oil-oxidizing microbial population.

  5. Risk factors and outcomes for patients with bloodstream infection due to Acinetobacter baumannii-calcoaceticus complex.

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    Chopra, Teena; Marchaim, Dror; Johnson, Paul C; Awali, Reda A; Doshi, Hardik; Chalana, Indu; Davis, Naomi; Zhao, Jing J; Pogue, Jason M; Parmar, Sapna; Kaye, Keith S

    2014-08-01

    Identifying patients at risk for bloodstream infection (BSI) due to Acinetobacter baumannii-Acinetobacter calcoaceticus complex (ABC) and providing early appropriate therapy are critical for improving patient outcomes. A retrospective matched case-control study was conducted to investigate the risk factors for BSI due to ABC in patients admitted to the Detroit Medical Center (DMC) between January 2006 and April 2009. The cases were patients with BSI due to ABC; the controls were patients not infected with ABC. Potential risk factors were collected 30 days prior to the ABC-positive culture date for the cases and 30 days prior to admission for the controls. A total of 245 case patients were matched with 245 control patients. Independent risk factors associated with BSI due to ABC included a Charlson's comorbidity score of ≥ 3 (odds ratio [OR], 2.34; P = 0.001), a direct admission from another health care facility (OR, 4.63; P < 0.0001), a prior hospitalization (OR, 3.11; P < 0.0001), the presence of an indwelling central venous line (OR, 2.75; P = 0.011), the receipt of total parenteral nutrition (OR, 21.2; P < 0.0001), the prior receipt of β-lactams (OR, 3.58; P < 0.0001), the prior receipt of carbapenems (OR, 3.18; P = 0.006), and the prior receipt of chemotherapy (OR, 15.42; P < 0.0001). The median time from the ABC-positive culture date to the initiation of the appropriate antimicrobial therapy was 2 days (interquartile range [IQR], 1 to 3 days). The in-hospital mortality rate was significantly higher among case patients than among control patients (OR, 3.40; P < 0.0001). BSIs due to ABC are more common among critically ill and debilitated institutionalized patients, who are heavily exposed to health care settings and invasive devices.

  6. Productivity of cyclohexanone oxidation of the recombinant Corynebacterium glutamicum expressing chnB of Acinetobacter calcoaceticus.

    Science.gov (United States)

    Doo, Eun-Hee; Lee, Won-Heong; Seo, Hyo-Seel; Seo, Jin-Ho; Park, Jin-Byung

    2009-06-15

    The biocatalytic efficiency of recombinant Corynebacterium glutamicum expressing the chnB gene encoding cyclohexanone monooxygenase (CHMO) of Acinetobacter calcoaceticus NCIMB 9871 was investigated. Optimization of an expression system and induction conditions enabled the recombinant biocatalyst to produce CHMO to a specific activity of ca. 0.5 U mg(-1) protein. Tight control of feeding of an energy source (i.e., glucose) and dissolved oxygen tension during fed-batch culture-based biotransformation allowed the cells to produce epsilon-caprolactone to a concentration of 16.0 g l(-1). The specific and volumetric productivity for cyclohexanone oxidation were 0.12 g g drycells(-1)h(-1) (17.5 U g(-1) of dry cells) and 2.3 g l(-1)h(-1) (330 U l(-1)), respectively. These values correspond to over 5.4- and 2.7-fold of recombinant Escherichia coli expressing the same gene under similar reaction conditions. It could be concluded that the recombinant C. glutamicum is a promising biocatalyst for Baeyer-Villiger oxidations.

  7. Endemicity of Acinetobacter calcoaceticus-baumannii Complex in an Intensive Care Unit in Malaysia

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    Amreeta Dhanoa

    2015-01-01

    Full Text Available Introduction. Acinetobacter calcoaceticus-baumannii complex (ACB complex is a leading opportunistic pathogen in intensive care units (ICUs. Effective control of spread requires understanding of its epidemiological relatedness. This study aims to determine the genetic relatedness and antibiotic susceptibilities of ACB complex in an ICU in Malaysia. Methodology. Pulsed field gel electrophoresis (PFGE, E-test, and disk diffusion were used for isolates characterization. Results. During the study period (December 2011 to June 2012, 1023 patients were admitted to the ICU and 44 ACB complex (blood, n=21, and blind bronchial aspirates, n=23 were recovered from 38 ICU patients. Six isolates were from non-ICU patients. Of the 44 ICU isolates, 88.6% exhibited multidrug-resistant (MDR patterns. There was high degree of resistance, with minimum inhibitory concentration90 (MIC90 of >32 μg/mL for carbapenems and ≥256 μg/mL for amikacin, ampicillin/sulbactam, and cefoperazone/sulbactam. Isolates from the main PFGE cluster were highly resistant. There was evidence of dissemination in non-ICU wards. Conclusion. High number of clonally related MDR ACB complex was found. While the ICU is a likely reservoir facilitating transmission, importation from other wards may be important contributor. Early identification of strain relatedness and implementation of infection control measures are necessary to prevent further spread.

  8. Genotypic and Phenotypic Correlations of Multidrug-Resistant Acinetobacter baumannii-A. calcoaceticus Complex Strains Isolated from Patients at the National Naval Medical Center

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    Acinetobacter baumannii-calcoaceticus complex (ABC) infections have complicated the care of U.S. combat casualties. In this study, 102 ABC isolates from wounded soldiers treated at National Naval Medical Center (NNMC) were characterized by phenotype and genotype to identify clones in this population...

  9. Síndrome séptico por Acinetobacter calcoaceticus, variedad anitratus Septic syndrome due to acinetobacter calcoaceticus var. anitratus in an infant: report of a case and review of the subject

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    Carmen Tulia Zapata Muñoz

    1994-04-01

    Full Text Available Se presenta un caso de síndrome séptico por Acinetobacter calcoaceticus, variedad anitratus, adquirido en la comunidad por un niño inmunocompetente. Esta combinación de circunstancias es inusitada. Se manifestó por meningitis, compromiso del pulmón izquierdo y un absceso glúteo. El niño se recuperó completamente con la antibioterapia. Se propone éste como el primer caso informado en la literatura latinoamericana que reúne las condiciones anotadas. Se hace una síntesis de las características generales de la bacteria, la patogénesis de la infección y las principales enfermedades que produce, así como los medios existentes para prevenirla.

    We report on the case of an immunocompetent infant who presented with a septic syndrome due to a community-acquired infection by Acinetobacter calcoaceticus var. anitratus. Clinical manifestations were meningitis, left Iobar pneumonia with pleural effussion and a gluteal ascess. The patient fully recovered with antibiotic therapy. This case may be the first in the Latin-American medical literature with such unusual combination of features. A review is presented on the general characteristics of Acinetobacter, the pathogenesis of the infections It produces, the main clinical presentations and the methods of prevention.

  10. Using Vitek MALDI-TOF mass spectrometry to identify species belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex: a relevant alternative to molecular biology?

    Science.gov (United States)

    Pailhoriès, Hélène; Daure, Sophie; Eveillard, Matthieu; Joly-Guillou, Marie-Laure; Kempf, Marie

    2015-10-01

    Acinetobacter baumannii belongs to the Acinetobacter calcoaceticus-baumannii complex (Acb) containing 2 other pathogenic species: Acinetobacter pittii and Acinetobacter nosocomialis. Identification of these bacteria remains problematic despite the use of matrix-assisted laser ionization time-of-flight mass spectrometry (MALDI-TOF MS). Here, we enriched the SARAMIS™ database of the Vitek MS® plus mass spectrometer to improve the identification of species of the Acb complex. For each species, we incremented reference spectra. Then, a SuperSpectrum was created based on the selection of 40 specific masses. In a second step, we validated reference spectra and SuperSpectra with 100 isolates identified by rpoB gene sequencing. All the isolates were correctly identified by MALDI-TOF MS with the database we created as compared to the identifications obtained by rpoB sequencing. Our database enabled rapid and reliable identification of the pathogen species belonging to the Acb complex. Identification by MALDI-TOF MS with our database is a good alternative to molecular biology.

  11. The role of the genetic elements bla oxa and IS Aba 1 in the Acinetobacter calcoaceticus-Acinetobacter baumannii complex in carbapenem resistance in the hospital setting

    Directory of Open Access Journals (Sweden)

    Vanessa Cristine Kobs

    Full Text Available Abstract: INTRODUCTION: Members of the Acinetobacter genus are key pathogens that cause healthcare-associated infections, and they tend to spread and develop new antibiotic resistance mechanisms. Oxacillinases are primarily responsible for resistance to carbapenem antibiotics. Higher rates of carbapenem hydrolysis might be ascribed to insertion sequences, such as the ISAba1 sequence, near bla OXA genes. The present study examined the occurrence of the genetic elements bla OXA and ISAba1 and their relationship with susceptibility to carbapenems in clinical isolates of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex. METHODS: Isolates identified over 6 consecutive years in a general hospital in Joinville, Southern Brazil, were evaluated. The investigation of 5 families of genes encoding oxacillinases and the ISAba1 sequence location relative to bla OXA genes was conducted using polymerase chain reaction. RESULTS: All isolates presented the bla OXA-51-like gene (n = 78, and 91% tested positive for the bla OXA-23-like gene (n = 71. The presence of ISAba1 was exclusively detected in isolates carrying the bla OXA-23-like gene. All isolates in which ISAba1 was found upstream of the bla OXA-23-like gene (n = 69 showed resistance to carbapenems, whereas the only isolate in which ISAba1 was not located near the bla OXA-23-like gene was susceptible to carbapenems. The ISAba1 sequence position of another bla OXA-23-like-positive isolate was inconclusive. The isolates exclusively carrying the bla OXA-51-like gene (n = 7 showed susceptibility to carbapenems. CONCLUSIONS: The presence of the ISAba1 sequence upstream of the bla OXA-23-like gene was strongly associated with carbapenem resistance in isolates of the A. calcoaceticus-A. baumannii complex in the hospital center studied.

  12. Study of a hydrocarbon-utilizing and emulsifier-producing Acinetobacter calcoaceticus strain isolated from heating oil.

    Science.gov (United States)

    Marín, M M; Pedregosa, A M; Ortiz, M L; Laborda, F

    1995-12-01

    Twenty bacterial strains were isolated from a sample of contaminated heating oil and screened for their ability to use petroleum and several common fuels as the sole source of carbon and energy. One of the isolates, named MM5, was able to grow on petroleum derivatives and brought about an emulsification of those compounds. Gas chromatography studies showed that strain MM5 was able to degrade hydrocarbons of heating oil. MM5 has been tentatively identified as a strain of Acinetobacter calcoaceticus. The fine structure of MM5 was examined by transmission electron microscopy. Incubation in the presence of hydrocarbon substrates resulted in the development of intracellular electron-transparent inclusions. These structures were absent in the non-hydrocarbon cultures studied.

  13. Decolorization of Textile Dyes and Degradation of Mono-Azo Dye Amaranth by Acinetobacter calcoaceticus NCIM 2890.

    Science.gov (United States)

    Ghodake, Gajanan; Jadhav, Umesh; Tamboli, Dhawal; Kagalkar, Anuradha; Govindwar, Sanjay

    2011-10-01

    Acinetobacter calcoaceticus NCIM 2890 (A. caloaceticus) was found to decolorize 20 different textile dyes of various classes. Decolorization of an azo dye amaranth was observed effectively (91%) at static anoxic condition, whereas agitated culture grew well but showed less decolorization (68%) within 48 h of incubation. Induction of intracellular and extracellular lignin peroxidase, intracellular laccase, dichlorophenol indophenol (DCIP) reductase and riboflavin reductase represented their involvement in the biodegradation of amaranth. The products obtained after degradation of Amaranth were characterized as naphthalene sulfamide, hydroxyl naphthalene diazonium and naphthalene diazonium. The germination and growth of Sorghum vulgare and Phaseolus mungo seeds, and the growth of E. coli and Bacillus substilis were not inhibited by the metabolic products of the dye.

  14. Purification and partial characterization of lignin peroxidase from Acinetobacter calcoaceticus NCIM 2890 and its application in decolorization of textile dyes.

    Science.gov (United States)

    Ghodake, Gajanan S; Kalme, Satish D; Jadhav, Jyoti P; Govindwar, Sanjay P

    2009-01-01

    Lignin peroxidase was purified (72-fold) from Acinetobacter calcoaceticus NCIM 2890. The purified lignin peroxidase (55-65 kDa) showed dimeric nature. The maximum enzyme activity was observed at pH 1.0, between a broad temperature range of 50 and 70 degrees C, at H2O2 concentration (40 mM) and the substrate concentration (n-propanol, 100 mM). Purified lignin peroxidase was able to oxidize a variety of substrates including Mn2+, tryptophan, mimosine, L-Dopa, hydroquinone, xylidine, n-propanol, veratryl alcohol, and ten textile dyes of various groups indicating as a versatile peroxidase. Most of the dyes decolorized up to 90%. Tryptophan stabilizes the lignin peroxidase activity during decolorization of dyes.

  15. OXA-Carbapenemases Present in Clinical Acinetobacter baumannii-calcoaceticus Complex Isolates from Patients in Kurdistan Region, Iraq.

    Science.gov (United States)

    Ganjo, Aryann R; Maghdid, Delshad M; Mansoor, Isam Y; Kok, Dik J; Severin, Juliette A; Verbrugh, Henri A; Kreft, Deborah; Fatah, M H; Alnakshabandi, A A; Dlnya, Asad; Hammerum, Anette M; Ng, Kim; Goessens, Wil

    2016-12-01

    In addition to intrinsic resistance in Acinetobacter baumannii, many different types of acquired resistance mechanisms have been reported, including the presence of VIM and IMP metallo β-lactamases and also of blaOXA-23-like and blaOXA-58-like enzymes. In the Kurdistan region of Iraq, the multiresistant A. baumannii-calcoaceticus complex is prevalent. We characterized the different mechanisms of resistance present in clinical isolates collected from different wards and different hospitals from the Kurdistan region. One hundred twenty clinical nonduplicate A. baumannii-calcoaceticus complex isolates were collected from four hospitals between January 2012 and October 2013. The identification of the isolates was confirmed by MALDI-TOF. The susceptibility to different antibiotics was determined by disk diffusion and analyzed in accordance to EUCAST guidelines. By PCR, the presence of blaOXA-51-like, blaOXA-23-like, blaOXA-24-like, and blaOXA-58-like genes was determined as well as the presence of the insertion element ISAba1. Clonal diversity was analyzed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme ApaI and, in addition, multilocus sequence typing (MLST) was performed on a selected subset of 15 isolates. All 120 A. baumannii isolates harbored blaOXA-51-like genes. One hundred one out of 110 (92%) imipenem (IMP)-resistant A. baumannii-calcoaceticus complex isolates additionally carried the blaOXA-23-like gene and four isolates (3%) were positive for blaOXA-24-like. All 101 blaOXA-23-like-positive isolates had the ISAba1 insertion sequence, 1,600 bp upstream of the blaOXA-23-like gene. The blaOXA-58-like gene was not detected in any of the 110 IMP-resistant strains. Eight different PFGE clusters were identified and distributed over the different hospitals. MLST analysis performed on a subset of 15 representative isolates revealed the presence of the international clone ST2 (Pasteur). Besides ST2 (Pasteur), also many other STs (Pasteur) were

  16. Molecular Epidemiology and Clinical Impact of Acinetobacter calcoaceticus-baumannii Complex in a Belgian Burn Wound Center.

    Directory of Open Access Journals (Sweden)

    Daniel De Vos

    Full Text Available Multidrug resistant Acinetobacter baumannii and its closely related species A. pittii and A. nosocomialis, all members of the Acinetobacter calcoaceticus-baumannii (Acb complex, are a major cause of hospital acquired infection. In the burn wound center of the Queen Astrid military hospital in Brussels, 48 patients were colonized or infected with Acb complex over a 52-month period. We report the molecular epidemiology of these organisms, their clinical impact and infection control measures taken. A representative set of 157 Acb complex isolates was analyzed using repetitive sequence-based PCR (rep-PCR (DiversiLab and a multiplex PCR targeting OXA-51-like and OXA-23-like genes. We identified 31 rep-PCR genotypes (strains. Representatives of each rep-type were identified to species by rpoB sequence analysis: 13 types to A. baumannii, 10 to A. pittii, and 3 to A. nosocomialis. It was assumed that isolates that belonged to the same rep-type also belonged to the same species. Thus, 83.4% of all isolates were identified to A. baumannii, 9.6% to A. pittii and 4.5% to A. nosocomialis. We observed 12 extensively drug resistant Acb strains (10 A. baumannii and 2 A. nosocomialis, all carbapenem-non-susceptible/colistin-susceptible and imported into the burn wound center through patients injured in North Africa. The two most prevalent rep-types 12 and 13 harbored an OXA-23-like gene. Multilocus sequence typing allocated them to clonal complex 1 corresponding to EU (international clone I. Both strains caused consecutive outbreaks, interspersed with periods of apparent eradication. Patients infected with carbapenem resistant A. baumannii were successfully treated with colistin/rifampicin. Extensive infection control measures were required to eradicate the organisms. Acinetobacter infection and colonization was not associated with increased attributable mortality.

  17. Silver nanoparticles from Prosopis glandulosa and their potential application as biocontrol of Acinetobacter calcoaceticus and Bacillus cereus

    Directory of Open Access Journals (Sweden)

    Ali Abdelmoteleb

    2017-01-01

    Full Text Available In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS, zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (−200 mV. The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. glandulosa.

  18. Synthesis, optimization, and characterization of silver nanoparticles from Acinetobacter calcoaceticus and their enhanced antibacterial activity when combined with antibiotics

    Directory of Open Access Journals (Sweden)

    Singh R

    2013-11-01

    Full Text Available Richa Singh,1 Priyanka Wagh,1 Sweety Wadhwani,1 Sharvari Gaidhani,2 Avinash Kumbhar,3 Jayesh Bellare,4 Balu Ananda Chopade1 1Department of Microbiology, University of Pune, Pune, Maharashtra, India; 2Institute of Bioinformatics and Biotechnology, University of Pune, Pune, Maharashtra, India; 3Department of Chemistry, University of Pune, Pune, Maharashtra, India; 4Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, Maharashtra, India Background: The development of nontoxic methods of synthesizing nanoparticles is a major step in nanotechnology to allow their application in nanomedicine. The present study aims to biosynthesize silver nanoparticles (AgNPs using a cell-free extract of Acinetobacter spp. and evaluate their antibacterial activity. Methods: Eighteen strains of Acinetobacter were screened for AgNP synthesis. AgNPs were characterized using various techniques. Reaction parameters were optimized, and their effect on the morphology of AgNPs was studied. The synergistic potential of AgNPs on 14 antibiotics against seven pathogens was determined by disc-diffusion, broth-microdilution, and minimum bactericidal concentration assays. The efficacy of AgNPs was evaluated as per the minimum inhibitory concentration (MIC breakpoints of the Clinical and Laboratory Standards Institute (CLSI guidelines. Results: Only A. calcoaceticus LRVP54 produced AgNPs within 24 hours. Monodisperse spherical nanoparticles of 8–12 nm were obtained with 0.7 mM silver nitrate at 70°C. During optimization, a blue-shift in ultraviolet-visible spectra was seen. X-ray diffraction data and lattice fringes (d =0.23 nm observed under high-resolution transmission electron microscope confirmed the crystallinity of AgNPs. These AgNPs were found to be more effective against Gram-negative compared with Gram-positive microorganisms. Overall, AgNPs showed the highest synergy with vancomycin in the disc-diffusion assay. For Enterobacter

  19. Synergistic effect of thermophilic temperature and biosurfactant produced by Acinetobacter calcoaceticus BU03 on the biodegradation of phenanthrene in bioslurry system.

    Science.gov (United States)

    Zhao, Zhenyong; Selvam, Ammaiyappan; Wong, Jonathan Woon-Chung

    2011-06-15

    This study aimed at investigating the synergistic effect of temperature and biosurfactant on the biodegradation of phenanthrene in bioslurry. Bench-scale bioslurry experiments were conducted at 25 and 55°C. The desorption rate coefficients of phenanthrene (K(des)) obtained using the pseudo-first order model were 0.0026 and 0.0035 kg mg(-1)h(-1) at 25 and 55°C, respectively. Addition of 1500 mg L(-1) biosurfactant, produced by Acinetobacter calcoaceticus BU03, marginally increased the K(des) at 25°C since most of biosurfactant was sorbed onto soil; however, significantly increased the K(des) to 0.0087 kg mg(-1)h(-1) at 55°C as the thermophilic temperature reduced the adsorption of the biosurfactant onto soil and subsequently enhanced the desorption of phenanthrene. The biodegradation of phenanthrene well fitted pseudo-first order kinetics based on the assumption that biodegradation was limited by the desorption. About 78.7% of phenanthrene was degraded in 30 days at 25°C; and addition of biosurfactant did not affect the biodegradation. However, addition of the biosurfactant or inoculation of A. calcoaceticus BU03 at 55°C significantly enhanced the biodegradation by increasing the K(des). Results indicate that synergistic application of thermophilic temperature and biosurfactant or inoculation of biosurfactant producing microorganisms is an effective and innovative method to enhance the efficiency of PAH degradation in bioslurry system.

  20. A novel bifunctional wax ester synthase/acyl-CoA:diacylglycerol acyltransferase mediates wax ester and triacylglycerol biosynthesis in Acinetobacter calcoaceticus ADP1.

    Science.gov (United States)

    Kalscheuer, Rainer; Steinbüchel, Alexander

    2003-03-07

    Triacylglycerols (TAGs) and wax esters are neutral lipids with considerable importance for dietetic, technical, cosmetic, and pharmaceutical applications. Acinetobacter calcoaceticus ADP1 accumulates wax esters and TAGs as intracellular storage lipids. We describe here the identification of a bifunctional enzyme from this bacterium exhibiting acyl-CoA:fatty alcohol acyltransferase (wax ester synthase, WS) as well as acyl-CoA:diacylglycerol acyltransferase (DGAT) activity. Experiments with a knock-out mutant demonstrated the key role of the bifunctional WS/DGAT for biosynthesis of both storage lipids in A. calcoaceticus. This novel type of long-chain acyl-CoA acyltransferase is not related to known acyltransferases including the WS from jojoba (Simmondsia chinensis), the DGAT1 or DGAT2 families present in yeast, plants, and animals, and the phospholipid:diacylglycerol acyltransferase catalyzing TAG formation in yeast and plants. A large number of WS/DGAT-related proteins were identified in Mycobacterium and Arabidopsis thaliana indicating an important function of these proteins. WS and DGAT activity was demonstrated for the translational product of one WS/DGAT homologous gene from M. smegmatis mc(2)155. The potential of WS/DGAT to establish novel processes for biotechnological production of jojoba-like wax esters was demonstrated by heterologous expression in recombinant Pseudomonas citronellolis. The potential of WS/DGAT as a selective therapeutic target of mycobacterial infections is discussed.

  1. Plant growth-promoting bacterium Acinetobacter calcoaceticus P23 increases the chlorophyll content of the monocot Lemna minor (duckweed) and the dicot Lactuca sativa (lettuce).

    Science.gov (United States)

    Suzuki, Wakako; Sugawara, Masayuki; Miwa, Kyoko; Morikawa, Masaaki

    2014-07-01

    Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium that was isolated from the surface of duckweed (Lemna aoukikusa). The bacterium was observed to colonize on the plant surfaces and increase the chlorophyll content of not only the monocotyledon Lemna minor but also the dicotyledon Lactuca sativa in a hydroponic culture. This effect on the Lactuca sativa was significant in nutrient-poor (×1/100 dilution of H2 medium) and not nutrient-rich (×1 or ×1/10 dilutions of H2 medium) conditions. Strain P23 has the potential to play a part in the future development of fertilizers and energy-saving hydroponic agricultural technologies.

  2. OXA-carbapenemases present in clinical acinetobacter baumannii-calcoaceticus complex isolates from patients in kurdistan region, Iraq

    NARCIS (Netherlands)

    Ganjo, A.R. (Aryann R.); D.M. Maghdid (Delshad); Mansoor, I.Y. (Isam Y.); Kok, D.J. (Dik J.); J.A. Severin (Juliëtte); H.A. Verbrugh (Henri); D. Kreft; Fatah, M.H.; Alnakshabandi, A.A.; Dlnya, A. (Asad); Hammerum, A.M. (Anette M.); Ng, K. (Kim); W.H.F. Goessens (Wil)

    2016-01-01

    markdownabstractIn addition to intrinsic resistance in Acinetobacter baumannii, many different types of acquired resistance mechanisms have been reported, including the presence of VIM and IMP metallo β-lactamases and also of blaOXA-23-like and blaOXA-58-like enzymes. In the Kurdistan region of Iraq

  3. Emergence of New Delhi metallo-beta-lactamase 1 and other carbapenemase-producing Acinetobacter calcoaceticus-baumannii complex among patients in hospitals in Ha Noi, Viet Nam.

    Science.gov (United States)

    Tran, D N; Tran, H H; Matsui, M; Suzuki, M; Suzuki, S; Shibayama, K; Pham, T D; Van Phuong, T T; Dang, D A; Trinh, H S; Loan, C T; Nga, L T V; van Doorn, H R; Wertheim, H F L

    2017-02-01

    Acinetobacter baumannii is an important cause of multidrug-resistant hospital acquired infections in the world. Here, we investigate the presence of NDM-1 and other carbapenemases among carbapenem-resistant A. baumannii isolated between August 2010 and December 2014 from three large hospitals in Hanoi, Vietnam. We identified 23/582 isolates (4 %) (11 from hospital A, five from hospital B, and seven from hospital C) that were NDM-1 positive, and among them 18 carried additional carbapenemase genes, including seven isolates carrying NDM-1, IMP-1, and OXA-58 with high MICs for carbapenems. Genotyping indicated that NDM-1 carrying A. baumannii have expanded clonally in these hospitals. Five new STs (ST1135, ST1136, ST1137, ST1138, and ST1139) were identified. One isolate carried NDM-1 on a plasmid belonging to the N-repA replicon type; no NDM-1-positive plasmids were identified in the other isolates. We have shown the extent of the carbapenem resistance and the local clonal spread of A. baumannii carrying NDM-1 in these hospitals; coexistence of NDM-1 and IMP-1 is reported for the first time from Vietnam here, and this will further seriously limit future therapeutic options.

  4. Novel Therapies for Acinetobacter Osteomyelitis

    Science.gov (United States)

    2009-01-01

    Acinetobacter baumannii , Osteomyelitis, Colistin 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF...Words: Multi-Drug Resistant, Acinetobacter baumannii , Osteomyelitis, Colistin Page 1 of 21 John Wiley & Sons, Inc. Journal of Orthopaedic Research 1...which is responsible for >80% of OM infections, 12 Acinetobacter baumannii -calcoaceticus complex (ABC) are Gram-negative, non-fermentative, non-spore

  5. Enrichment of Acinetobacter spp. from food samples.

    Science.gov (United States)

    Carvalheira, Ana; Ferreira, Vânia; Silva, Joana; Teixeira, Paula

    2016-05-01

    Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p Acinetobacter was applied to detect Acinetobacter spp. in different foods. Fourteen different presumptive acinetobacters were recovered and assumed to represent nine different strains on the basis of REP-PCR typing. Eight of these strains were identified by rpoB gene analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species.

  6. Development and Evaluation of Species-Specific PCR for Detection of Nine Acinetobacter Species.

    Science.gov (United States)

    Li, Xue Min; Choi, Ji Ae; Choi, In Sun; Kook, Joong Ki; Chang, Young-Hyo; Park, Geon; Jang, Sook Jin; Kang, Seong Ho; Moon, Dae Soo

    2016-05-01

    Molecular methods have the potential to improve the speed and accuracy of Acinetobacter species identification in clinical settings. The goal of this study is to develop species-specific PCR assays based on differences in the RNA polymerase beta-subunit gene (rpoB) to detect nine commonly isolated Acinetobacter species including Acinetobacter baumannii, Acinetobacter calcoaceticus, Acinetobacter pittii, Acinetobacter nosocomialis, Acinetobacter lwoffii, Acinetobacter ursingii, Acinetobacter bereziniae, Acinetobacter haemolyticus, and Acinetobacter schindleri. The sensitivity and specificity of these nine assays were measured using genomic DNA templates from 55 reference strains and from 474 Acinetobacter clinical isolates. The sensitivity of A. baumannii-specific PCR assay was 98.9%, and the sensitivity of species-specific PCR assays for all other species was 100%. The specificities of A. lwoffii- and A. schindleri-specific PCR were 97.8 and 98.9%, respectively. The specificity of species-specific PCR for all other tested Acinetobacter species was 100%. The lower limit of detection for the nine species-specific PCR assays developed in this study was 20 or 200 pg of genomic DNA from type strains of each species. The Acinetobacter species-specific PCR assay would be useful to determine the correct species among suggested candidate Acinetobacter species when conventional methods including MALDI-TOF MS identify Acinetobacter only to the genus level. The species-specific assay can be used to screen large numbers of clinical and environmental samples obtained for epidemiologic study of Acinetobacter for the presence of target species.

  7. Rapid identification of Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii with a multiplex PCR assay.

    Science.gov (United States)

    Chen, Te-Li; Lee, Yi-Tzu; Kuo, Shu-Chen; Yang, Su-Pen; Fung, Chang-Phone; Lee, Shou-Dong

    2014-09-01

    Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii are clinically relevant members of the Acinetobacter calcoaceticus-A. baumannii (Acb) complex and important nosocomial pathogens. These three species are genetically closely related and phenotypically similar; however, they differ in their epidemiology, antibiotic resistance and pathogenicity. In this study, we investigated the use of a multiplex PCR-based assay designed to detect internal fragments of the 16S-23S rRNA intergenic region and the gyrB and recA genes. The assay was capable of differentiating A. baumannii, A. nosocomialis and A. pittii in a reliable manner. In 23 different reference strains and 89 clinical isolates of Acinetobacter species, the assay accurately identified clinically relevant Acb complex species except those 'between 1 and 3' or 'close to 13TU'. None of the non-Acb complex species was misidentified. In an analysis of 1034 positive blood cultures, the assay had a sensitivity of 92.4 % and specificity of 98.2 % for Acb complex identification. Our results show that a single multiplex PCR assay can reliably differentiate clinically relevant Acb complex species. Thus, this method may be used to better understand the clinical differences between infections caused by these species.

  8. Clinical outcomes of hospital-acquired infection with Acinetobacter nosocomialis and Acinetobacter pittii.

    Science.gov (United States)

    Chusri, Sarunyou; Chongsuvivatwong, Virasakdi; Rivera, Jesabel I; Silpapojakul, Kachornsakdi; Singkhamanan, Kamonnut; McNeil, Edward; Doi, Yohei

    2014-07-01

    The role of Acinetobacter nosocomialis and Acinetobacter pittii, which belong to the A. calcoaceticus-A. baumannii complex, in hospital-acquired infections is increasingly recognized. Here we describe a retrospective cohort study of hospital-acquired A. calcoaceticus-A. baumannii complex infections at a university hospital in Thailand. A total of 222 unique cases were identified between January 2010 and December 2011. The genomospecies of the A. calcoaceticus-A. baumannii complex isolates were classified as follows: A. baumannii, 197 (89%); A. nosocomialis, 18 (8%); and A. pittii, 7 (3%). All A. nosocomialis and A. pittii isolates were susceptible to imipenem and meropenem. The patients infected with A. nosocomialis and A. pittii had lower 30-day mortality than those infected with carbapenem-susceptible A. baumannii (P = 0.025) and carbapenem-resistant A. baumannii (P = 0.013). The factors influencing 30-day mortality were infection with non-baumannii A. calcoaceticus-A. baumannii complex (hazard ratio [HR], 0.12; 95% confidence interval [CI], 0.03 to 0.51; P = 0.004), infection with carbapenem-resistant A. baumannii (HR, 1.57; 95% CI, 0.89 to 2.79; P = 0.105), appropriate empirical antimicrobial therapy (HR, 0.38; 95% CI, 0.23 to 0.61; P infected with A. nosocomialis or A. pittii than for those infected with either carbapenem-susceptible A. baumannii or carbapenem-resistant A. baumannii, but no differences in survival rates were observed between carbapenem-susceptible A. baumannii and carbapenem-resistant A. baumannii. These findings suggest intrinsic differences in virulence between non-baumannii A. calcoaceticus-A. baumannii complex species and A. baumannii but not between carbapenem-susceptible and resistant A. baumannii.

  9. [Problem of treatment for pyo-inflammatory complications caused by Acinetobacter].

    Science.gov (United States)

    Bogomolova, N S; Bol'shakov, L V; Kuznetsova, S M

    2014-01-01

    The article deals with analysis of a detection frequency and antibacterial treatment resistance of Acinetobacter spp.of different species affiliation. Strains of bacteria detected in patients with pyo-inflammatory complications after surgeries (period from 2010 to 2012) were involved in the study 137 strains of Acinetobacter spp. were detected and studied Fraction of Acinetobacter spp. in 2010, 2011 and 2012 was 2.3, 3 and 3.4% respectively. Fraction of P. aeruginosain all non-fermentative Gram-negative bacteria (NFGNB) decreased by 120% and fraction of Acinetobacter spp. increased by 200-250%. Acinetobacter spp. detection frequency was not significantly changed in the period from 2006 to 2012. However the fraction of Acinetobacter spp. in NFGNB increased by 150% and was 29% in 2012. Detection frequency of A. baumanii sharply increased in 2012. A study of antibacterial treatment resistance of Acinetobacter spp. (10 antibacterial medicines) showed that Polymyxin B and E (Colistin) was the most effective medicine for A. baumanii and A. calcoaceticus infection. 85-95% of Acinetobacter spp.strains kept sensitivity to this antibacterial medicine. 66-88.9% of A. baumanii strains, 66.7-81.8% of A. alcoaceticus and 66.6% of other Acinetobacter spp. were sensitive to Tigecycline. Dioxidine effectiveness was close to Tigecycline in 66.7-80% of A. baumanii strains. 85-100% of A. calcoaceticus strains were sensitive to Dioxidine. There is a trend of decreasing of A. baumanii sensitivity to Carbapenems by 200%. Fraction of strains sensitive to Meropenem and Imipenem in 2012 was 21.4% and 16.7% respectively. All studied strains of A. lwoffi and A. haemolyticus kept sensitivity to Carbapenems. In 2012 23.8% of A. baumanii and 50% of A. calcoaceticus strains were sensitivity to Amikacin, meanwhile A. lwoffi and A. haemolyticus were not sensitive to this medicine. 31.3% of A. baumanii and 50% of A. calcoaceticus strains were sensitive to Ceftazidime/Sulbactam. 5.3% of A. baumanii

  10. Molecular epidemiology of Acinetobacter baumannii and Acinetobacter nosocomialis in Germany over a 5-year period (2005-2009).

    Science.gov (United States)

    Schleicher, X; Higgins, P G; Wisplinghoff, H; Körber-Irrgang, B; Kresken, M; Seifert, H

    2013-08-01

    To investigate the species distribution within the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and the molecular epidemiology of A. baumannii and Acinetobacter nosocomialis, 376 Acinetobacter isolates were collected prospectively from hospitalized patients at 15 medical centres in Germany during three surveillance studies conducted over a 5-year period. Species identification was performed by molecular methods. Imipenem minimum inhibitory concentrations (MIC) were determined by broth microdilution. The prevalence of the most common carbapenemase-encoding genes was investigated by oxacillinase (OXA) -multiplex polymerase chain reaction (PCR). The molecular epidemiology was investigated by repetitive sequence-based PCR (rep-PCR; DiversiLab™). Acinetobacter pittii was the most prevalent Acinetobacter species (n = 193), followed by A. baumannii (n = 140), A. calcoaceticus (n = 10) and A. nosocomialis (n = 8). The majority of A. baumannii was represented by sporadic isolates (n = 70, 50%) that showed unique rep-PCR patterns, 25 isolates (18%) clustered with one or two other isolates, and only 45 isolates (32%) belonged to one of the previously described international clonal lineages. The most prevalent clonal lineage was international clone (IC) 2 (n = 34) and IC 1 (n = 6). According to CLSI, 25 A. baumannii isolates were non-susceptible to imipenem (MIC ≥ 8 mg/L), all of which produced an OXA-58-like or OXA-23-like carbapenemase. The rate of imipenem susceptibility among A. baumannii isolates decreased from 96% in 2005 to 76% in 2009. All other Acinetobacter isolates were susceptible to imipenem. The population structure of carbapenem-susceptible A. baumannii in Germany is highly diverse. Imipenem non-susceptibility was strongly associated with the clonal lineages IC 2 and IC 1. These data underscore the high clonality of carbapenem-resistant A. baumannii isolates.

  11. A cluster of Acinetobacter Pneumonia in foundry workers

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    Cordes, L.G.; Brink, E.W.; Checko, P.J.; Lentnek, A.; Lyons, R.W.; Hayes, P.S.; Wu, T.C.; Tharr, D.G.; Fraser, D.W.

    1981-12-01

    In a 3-month period, three men who had worked for 5 to 19 years as welders or grinders of steel castings in a foundry acquired pneumonia caused by Acinetobacter calcoaceticus variety anitratus serotype 7J. Two of the men died, and postmortem examination showed mixed-dust pneumoconiosis with iron particles in the lungs. A calcoaceticus variety anitratus serotype 7J was isolated from the air in the foundry but the source was not found. The prevalence of antibody titers of 64 or greater to the 7J strain was significantly higher among foundry workers (15%) than among community controls (2%) (p less than 0.01). Sampling showed that the concentrations of total and metallic particles (especially iron) and of free silica in air inhaled by welders and grinders at the foundry frequently exceeded acceptable levels. These findings suggest that chronic exposure to such particles may increase susceptibility to infection by this organism, which rarely affects healthy people.

  12. The success of acinetobacter species; genetic, metabolic and virulence attributes.

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    Anton Y Peleg

    Full Text Available An understanding of why certain Acinetobacter species are more successful in causing nosocomial infections, transmission and epidemic spread in healthcare institutions compared with other species is lacking. We used genomic, phenotypic and virulence studies to identify differences between Acinetobacter species. Fourteen strains representing nine species were examined. Genomic analysis of six strains showed that the A. baumannii core genome contains many genes important for diverse metabolism and survival in the host. Most of the A. baumannii core genes were also present in one or more of the less clinically successful species. In contrast, when the accessory genome of an individual A. baumannii strain was compared to a strain of a less successful species (A. calcoaceticus RUH2202, many operons with putative virulence function were found to be present only in the A. baumannii strain, including the csu operon, the acinetobactin chromosomal cluster, and bacterial defence mechanisms. Phenotype microarray analysis showed that compared to A. calcoaceticus (RUH2202, A. baumannii ATCC 19606(T was able to utilise nitrogen sources more effectively and was more tolerant to pH, osmotic and antimicrobial stress. Virulence differences were also observed, with A. baumannii ATCC 19606(T, A. pittii SH024, and A. nosocomialis RUH2624 persisting and forming larger biofilms on human skin than A. calcoaceticus. A. baumannii ATCC 19606(T and A. pittii SH024 were also able to survive in a murine thigh infection model, whereas the other two species were eradicated. The current study provides important insights into the elucidation of differences in clinical relevance among Acinetobacter species.

  13. Carbapenem resistance in a human clinical isolate identified to be closely related to Acinetobacter indicus.

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    Bonnin, Rémy A; Poirel, Laurent; van der Reijden, Tanny J K; Dijkshoorn, Lenie; Lescat, Mathilde; Nordmann, Patrice

    2014-10-01

    Here we report a case of carbapenem resistance in a human clinical isolate that was found to be closely related to the newly described environmental species Acinetobacter indicus. This strain harboured the blaOXA-23 carbapenemase gene located on a conjugative plasmid. Partial sequencing of 16S rDNA and rpoB genes, together with matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) analysis, showed that this strain was distantly related to the Acinetobacter baumannii-calcoaceticus complex and was closely related to A. indicus.

  14. Combination of ARDRA and RAPD genotyping techniques in identification of Acinetobacter spp. genomic species

    Institute of Scientific and Technical Information of China (English)

    Yong ZHANG; Yuqing CHEN; Yingchun TANG; Kouxing ZHANG

    2008-01-01

    A total of 10 non-repetitive multi-drug-resist-ant Acinetobacter strains were collected. With reference to A. calcoaceticus (ATCC23055), A. baumannii (ATCC19606), A. lwoffii (ATCC17986), and A. junii (NCTC5866), DNA fingerprint technique, amplified ribo-somal DNA restriction analysis (ARDRA), and random amplified polymorphism DNA (RAPD) were carried out to identify the genomic species of Acinetobacter spp. The distances between them were calculated by the unweighted pair group method with arithmetic (UPGMA). Genotypes ofAcinetobacter spp. were effectively classified and an A. junii together with nine A. baumannii isolates was genomically identified. The combination of ARDRA and RAPD DNA-fingerprint technique shows high com-plementarity, and could be a useful tool in Acinetobacter genomic species identification.

  15. Blood stream infections caused by Acinetobacter baumannii group in Japan - Epidemiological and clinical investigation.

    Science.gov (United States)

    Fujikura, Yuji; Yuki, Atsushi; Hamamoto, Takaaki; Kawana, Akihiko; Ohkusu, Kiyofumi; Matsumoto, Tetsuya

    2016-06-01

    Acinetobacter calcoaceticus-Acinetobacter baumannii complex, especially A. baumannii, Acinetobacter pittii and Acinetobacter nosocomialis, constitutes an important group of nosocomial pathogens; however, epidemiological or clinical characteristics and prognosis is limited in Japan. From 2009 to 2013, 47 blood stream infection cases resulting from A. baumannii group were reviewed at the National Defense Medical College, an 800-bed tertiary hospital. To determine the genospecies, further comparative nucleotide sequence analyses of the RNA polymerase b-subunit (rpoB) gene were performed. Sequence analysis of rpoB gene showed that 25 (49.0%), 17 (33.3%) and 5 (9.8%) cases were caused by A. baumannii, A. pittii and A. nosocomialis, respectively. The 30-day and in-hospital mortality rates of A. baumannii were 8.5% and 25.5%, respectively, and there were no significant differences between Acinetobacter species. Clinical characteristics were statistically insignificant. Multidrug-resistant Acinetobacter species were detected in 3 cases (5.9%) with same pulsed-field gel electrophoresis (PFGE) pattern and A. baumannii was less susceptible to amikacin and levofloxacin. In this study, the mortality and clinical characteristics were similar among A. baumannii group isolate cases despite some showing drug resistance. However, identification of Acinetobacter species helps to initiate appropriate antibiotic therapy in earlier treatment phase, because A. baumannii shows some drug resistance.

  16. Coaggregation between Rhodococcus and Acinetobacter strains isolated from the food industry.

    Science.gov (United States)

    Møretrø, Trond; Sharifzadeh, Shahab; Langsrud, Solveig; Heir, Even; Rickard, Alexander H

    2015-07-01

    In this study, coaggregation interactions between Rhodococcus and Acinetobacter strains isolated from food-processing surfaces were characterized. Rhodococcus sp. strain MF3727 formed intrageneric coaggregates with Rhodococcus sp. strain MF3803 and intergeneric coaggregates with 2 strains of Acinetobacter calcoaceticus (MF3293, MF3627). Stronger coaggregation between A. calcoaceticus MF3727 and Rhodococcus sp. MF3293 was observed after growth in batch culture at 30 °C than at 20 °C, after growth in tryptic soy broth than in liquid R2A medium, and between cells in exponential and early stationary phases than cells in late stationary phase. The coaggregation ability of Rhodococcus sp. MF3727 was maintained even after heat and Proteinase K treatment, suggesting its ability to coaggregate was protein independent whereas the coaggregation determinants of the other strains involved proteinaceous cell-surface-associated polymers. Coaggregation was stable at pH 5-9. The mechanisms of coaggregation among Acinetobacter and Rhodococcus strains bare similarity to those displayed by coaggregating bacteria of oral and freshwater origin, with respect to binding between proteinaceous and nonproteinaceous determinants and the effect of environmental factors on coaggregation. Coaggregation may contribute to biofilm formation on industrial food surfaces, protecting bacteria against cleaning and disinfection.

  17. Acinetobacter seifertii Isolated from China: Genomic Sequence and Molecular Epidemiology Analyses.

    Science.gov (United States)

    Yang, Yunxing; Wang, Jianfeng; Fu, Ying; Ruan, Zhi; Yu, Yunsong

    2016-03-01

    Clinical infections caused by Acinetobacter spp. have increasing public health concerns because of their global occurrence and ability to acquire multidrug resistance. Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex encompasses A. calcoaceticus, A. baumannii, A. pittii (formerly genomic species 3), and A nosocomial (formerly genomic species 13TU), which are predominantly responsible for clinical pathogenesis in the Acinetobacter genus. In our previous study, a putative novel species isolated from 385 non-A. baumannii spp. strains based on the rpoB gene phylogenetic tree was reported. Here, the putative novel species was identified as A. seifertii based on the whole-genome phylogenetic tree. A. seifertii was recognized as a novel member of the ACB complex and close to A. baumannii and A. nosocomials. Furthermore, we studied the characteristics of 10 A. seifertii isolates, which were distributed widely in 6 provinces in China and mainly caused infections in the elderly or children. To define the taxonomic status and characteristics, the biochemical reactions, antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequence analysis were performed. The phenotypic characteristics failed to distinguish A. serfertii from other species in the ACB complex. Most of the A. seifertii isolates were susceptible to antibiotics commonly used for nosocomial Acinetobacter spp. infections, but one isolate (strain A362) was resistant to ampicillin/sulbactam, ceftazidime and amikacin. The different patterns of MLST and PFGE suggested that the 10 isolates were not identical and lacked clonal relatedness. Our study reported for the first time the molecular epidemiological and genomic features of widely disseminated A. seifertii in China. These observations could enrich the knowledge of infections caused by non-A. baumannii and may provide a scientific basis for future clinical treatment.

  18. Species distribution and physiological characterization of Acinetobacter genospecies from healthy human skin of tribal population in India

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    Yavankar S

    2007-01-01

    Full Text Available Background: Various reports on distribution of Acinetobacter spp. from healthy human skin restricted to urban population. However, no such data is available from healthy human skin of tribal population not exposed to modern antibiotics during their life time. Purpose: Isolation, biotyping, distribution and physiological characterisation of Acinetobacter spp. from healthy human skin of tribal population. Methods: Tribal population of Toranmal area of Satpuda Ranges, Maharashtra, India were sampled for ten body sites. Tentative Acinetobacter isolates were confirmed to the genus level by chromosomal DNA transformation assay and to species level using Bouvet and Grimont system. Novel physiological characteristics like pH, temperature and salt tolerance were studied. All strains were screened for production of various enzymes. Results: One hundred and eighteen strains were isolated, which belonged to nine Acinetobacter genospecies. A. haemolyticus was most abundant followed by A. calcoaceticus and A. genospecies 1-3. Higher percentage of Acinetobacter was recovered from skin of nose, Pawara tribe and female volunteers. They showed wide variation in temperature, salt and pH tolerance. Most of the strains could produce enzymes viz, lipase, esterase, urease and amylase. Conclusions: Acinetobacter spp. belonging to nine genospecies were obtained in the present study. Physiological characteristics including high salt, temperature and acidic pH tolerance were helpful to differentiate between the commensal and pathogenic species of Acinetobacter genus.

  19. Staring at the cold sun: blue light regulation is distributed within the genus Acinetobacter.

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    Adrián Golic

    Full Text Available We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1 BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility.

  20. The Acinetobacter baumannii group: a systemic review

    OpenAIRE

    Zhang, Hua-Zhong; Zhang, Jin-Song; Qiao, Li

    2013-01-01

    BACKGROUND: The Acinetobacter baumannii group, including Acinetobacter baumannii, Acinetobacter genomospecies 3 and 13TU, is phenotypically indistinguishable and uniformly identified as Acinetobacter baumannii by laboratories of clinical microbiology. This review aimed to demonstrate the differences among them. METHODS: Literatures associated with the Acinetobacter baumannii group were identified and selected from PubMed databases and relevant journals. RESULTS: Acinetobacter genospecies 3 an...

  1. Lettuce and fruits as a source of multidrug resistant Acinetobacter spp.

    Science.gov (United States)

    Carvalheira, Ana; Silva, Joana; Teixeira, Paula

    2017-06-01

    The role of ready-to-eat products as a reservoir of pathogenic species of Acinetobacter remains unclear. The objective of the present study was to evaluate the presence of Acinetobacter species in lettuces and fruits marketed in Portugal, and their susceptibility to antimicrobials. Acinetobacter spp. were isolated from 77.9% of the samples and these microorganisms were also found as endophytes (i.e. present within the plant tissue) in 12 of 20 samples of lettuces analysed. Among 253 isolates that were identified as belonging to this genus, 181 presented different PFGE profiles, representing different strains. Based on the analysis of the partial sequence of rpoB, 175 strains were identified as members of eighteen distinct species and the remaining six strains may represent five new candidate species since their rpoB sequence similarities with type strains were less than 95%. Acinetobacter calcoaceticus and Acinetobacter johnsonii were the most common species, both with the frequency of 26.5%; and 11% of the strains belong to the Acinetobacter baumannii group (i.e. A. baumannii, Acinetobacter pittii, Acinetobacter seifertii and Acinetobacter nosocomialis), which is most frequently associated with nosocomial infections. Overall, the strains were least susceptible to piperacillin (80.1%), piperacillin-tazobactam (64.1%), ceftazidime (43.1%), ciprofloxacin (16.6%), trimethoprim-sulfamethoxazole (14.9%), imipenem (14.4%) and colistin (13.3%). The most active antimicrobials were minocycline and tetracycline, with 0.6% and 3.9% of strains resistant, respectively. About 29.8% of the strains were classified as multidrug-resistant (MDR), 4.4% as extensively drug-resistant (XDR) and the prevalence of MDR strains within the A. baumannii group (25%) was similar to other species (30.4%). The presence of clinically important species as well as MDR strains in lettuces and fruits may be a threat to public health considering that they may transmit these pathogens to environments

  2. Antimicrobial susceptibility pattern in nosocomial infections caused by Acinetobacter species in Asir Region, Saudi Arabia.

    Science.gov (United States)

    Abdalla, Nazar M; Osman, Amani A; Haimour, Waleed O; Sarhan, Mohammed A A; Mohammed, Mohammed N; Zyad, Eyhab M; Al-Ghtani, Abdalla M

    2013-03-15

    This study aimed at evaluating the sensitivity of antibiotics towards nosocomial infections caused by Acinetobacter species. The study took place during the period Dec. 2011- Dec. 2012 at Assir Central Hospital in collaboration with the department of microbiology, college of medicine, King Khalid University, Abha. A prospective study involving 150 patients presented with nosocomial infections due to Acinetobacter species detected by bacteriological tests; direct microscopy, culture in blood agar media, fermentation test in MacConkey media and MIC (minimum inhibitory concentration) for antibiotics sensitivity using Muller Hinton media and Chemical test using API 20. A 150 nosocomial infections in this study showed gram-negative coccobacilli, non motile, glucose-negative fermentor and oxidase negative. All isolates showed 100% sensitivity to: Imipramine, Meropenem, Colistin. From the rest of tested antibiotics the higher resistant ones were; Nitrofurantoin 87% and Cefoxitin 85%. The least resistant antibiotics; Imipenem 3% and Ticarcillin 7%. While variable resistance in the rest of tested antimicrobials. A 47 patients (31.3%) have used antibiotics prior to this study. The high rate of usage occurred in elder patients. The frequency of Acinetobacter calcoaceticus baumannii complex multi-drugs resistance ABCMDR is rising including almost all commonly used antibiotics. Only few antibiotics exert 100% sensitivity towards these bacteria.

  3. Radiation resistance of clinical Acinetobacter spp. : A need for concern

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    Christensen, E.A.; Gerner-Smidt, P.; Kristensen, H. (Control Department, Statens Seruminstitut, Copenhagen (Denmark))

    1991-06-01

    As part of an epidemiological investigation of hospital infections caused by Acinetobacter spp. the radiation resistance of 15 clinical isolates and four reference strains was assessed. The radiation resistance (in D-6 values, viz. the dose necessary for reducing the initial number of colony forming units by a factor of 10(6)) was, in general, higher in the isolates of A. radioresistens than in the isolates of the A. calcoaceticus-A. baumannii complex and of A. lwoffi. However, the least resistant isolates of A. radioresistens had a D-6 value equal to or lower than the most resistant isolates of the other groups. The lowest D-6 values found were for two of the reference strains. The highest D-6 value was 35 kGy. Three isolates of A. johnsonii could not survive long enough in a dried preparation to make an assessment of the D-6 values possible. The radiation resistance of the 15 clinical isolates in the present study was higher than the resistance found in a study of similar isolates in 1970.

  4. Clinical strains of acinetobacter classified by DNA-DNA hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Tjernberg, I.; Ursing, J. (Department of Medical Microbiology, University of Lund, Malmoe General Hospital, Malmoe (Sweden))

    1989-01-01

    A collection of Acinetobacter strains consisting of 168 consecutive clinical strains and 30 type and reference strains was studied by DNA-DNA hybridization and a few phenotypic tests. The field strains could be allotted to 13 DNA groups. By means of reference strains ten of these could be identified with groups described by Bouvet and Grimont (1986), while three groups were new; they were given the numbers 13-15. The type strain of A. radioresistens- recently described by Nishimura et al. (1988) - was shown to be a member of DNA group 12, which comprised 31 clinical isolates. Of the 19 strains of A. junii, eight showed hemolytic acitivity on sheep and human blood agar and an additional four strains on human blood agar only. Strains of this species have previously been regarded as non-hemolytic. Reciprocal DNA pairing data for the reference strains of the DNA gropus were treated by UPGMA clustering. The reference strains for A. calcoaceticus, A. baumannii and DNA groups 3 and 13 formed a cluster with about 70% relatedness within the cluster. Other DNA groups joined at levels below 60%. (author).

  5. Utility of Whole-Genome Sequencing in Characterizing Acinetobacter Epidemiology and Analyzing Hospital Outbreaks.

    Science.gov (United States)

    Fitzpatrick, Margaret A; Ozer, Egon A; Hauser, Alan R

    2016-03-01

    Acinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The band-based techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts.

  6. Urban riverine environment is a source of multidrug-resistant and ESBL-producing clinically important Acinetobacter spp.

    Science.gov (United States)

    Maravić, Ana; Skočibušić, Mirjana; Fredotović, Željana; Šamanić, Ivica; Cvjetan, Svjetlana; Knezović, Mia; Puizina, Jasna

    2016-02-01

    Some Acinetobacter species have emerged as very important opportunistic pathogens in humans. We investigated Acinetobacter spp. from the polluted urban riverine environment in Croatia in regard to species affiliation, antibiotic resistance pattern, and resistance mechanisms. Considerable number of isolates produced acquired extended-spectrum β-lactamase(s) (ESBLs), CTX-M-15 solely or with TEM-116. By Southern blot hybridization, bla TEM-116 was identified on plasmids ca. 10, 3, and 1.2 kb in Acinetobacter junii, A. gandensis, and A. johnsonii. The bla TEM-116-carrying plasmid in A. gandensis was successfully transferred by conjugation to azide-resistant Escherichia coli J53. A. radioresistens isolate also carried an intrinsic carbapenemase gene bla OXA-133 with ISAba1 insertion sequence present upstream to promote its expression. Majority of ESBL-producing isolates harbored integrases intI1 and/or intI2 and the sulfamethoxazole resistance gene sul1. Almost all isolates had overexpressed resistance-nodulation-cell division (RND) efflux system, indicating that this mechanism may have contributed to multidrug resistance phenotypes. This is the first report of environmental CTX-M-15-producing Acinetobacter spp. and the first identification of CTX-M-15 in A. johnsonii, A. junii, A. calcoaceticus, A. gandensis, A. haemolyticus, and A. radioresistens worldwide. We identified, also for the first time, the environmental Acinetobacter-producing TEM ESBLs, highlighting the potential risk for human health, and the role of these bacteria in maintenance and dissemination of clinically important antibiotic resistance genes in community through riverine environments.

  7. [Toxigenic effect of Acinetobacter baumannii isolated from children with acute diarrhoea].

    Science.gov (United States)

    Polanco, Nina; Manzi, Lorna

    2008-03-01

    Diarrheal diseases with diarrhea are the most frequent cause of morbidity and mortality in children; however the causative agent cannot be identified always, which suggests the presence of unknown enteropathogens inducing diarrhea. The isolation of Acinetobacter sp. from feces of children with acute diarrhea, unrelated to known enteropathogens motivated this investigation to detect a possible enterotoxigenic effect on HT-29 cells. The study population comprised 150 children with an age range from 0 to 5 years old; 120 were assisted in the "Hospital Materno Infantil del Este'' with gastrointestinal syndrome and 30 healthy controls who went to the center for routine analysis. In 25% of symptomatic patients were diagnosed parasites and bacteria, identified routinely. From four symptomatic patients were isolated three Acinetobacter baumannii strains and two A. calcoaceticus strains. The strains were cultured in brain-heart infusion for 24 and 48 hrs, at 35 degrees C, and the supernatants were obtained by centrifugation and filtration and their activity tested on HT-29 cell monolayers. The supernatants of the three strains of A. baumannii induced alterations of the cell monolayer, showed by detachments of cell monolayers, cell segregation, cell rounding and swelling. These effects were more intense with the 48 h culture exoproducts of the 016 strain, which were higher than the positive control. This toxigenic effect of A. baumannii, could represent a pathogenic mechanism whose definition requires more studies to determine the possible role in the pathogenicity of this bacillus.

  8. Insights into Acinetobacter baumannii pathogenicity.

    Science.gov (United States)

    Cerqueira, Gustavo M; Peleg, Anton Y

    2011-12-01

    Acinetobacter spp. have justifiably received significant attention from the public, scientific, and medical communities. Over recent years, Acinetobacter, particularly Acinetobacter baumannii, has become a "red-alert" human pathogen, primarily because of its exceptional ability to develop resistance to all currently available antibiotics. This characteristic is compounded by its unique abilities to survive in a diverse range of environments, including those within healthcare institutions, leading to problematic outbreaks. Historically, the virulence of the organism has been questioned, but recent clinical reports suggest that Acinetobacter can cause serious, life-threatening infections. Furthermore, its metabolic adaptability gives it a selective advantage in harsh hospital environments. This review focuses on current understanding of A. baumannii pathogenesis and the model systems used to study this interesting organism.

  9. Carbapenem resistance in Acinetobacter baumannii and other Acinetobacter spp. causing neonatal sepsis: focus on NDM-1 and its linkage to ISAba125

    Directory of Open Access Journals (Sweden)

    Somdatta Chatterjee

    2016-08-01

    Full Text Available Carbapenem-resistant determinants and their surrounding genetic structure were studied in Acinetobacter spp. from neonatal sepsis cases collected over 7 years at a tertiary care hospital. Acinetobacter spp. (n=68 were identified by ARDRA followed by susceptibility tests. Oxacillinases, metallo-β-lactamases (MBLs, extended-spectrum β-lactamases and AmpCs, were detected phenotypically and/or by PCR followed by sequencing. Transconjugants possessing the blaNDM-1 (New Delhi metallo-β-lactamases underwent further analysis for plasmids, integrons and associated genes. Genetic environment of the carbapenemases were studied by PCR mapping and sequencing. Multivariate logistic regression was used to identify risk factors for sepsis caused by NDM-1-harbouring organisms. A. baumannii (72% was the predominant species followed by A. calcoaceticus (10%, A. lwoffii (6%, 13TU (3%, A. junni (3%, 15TU (3%, A. haemolyticus (2% and 14TU (2%. Fifty six percent of the isolates were meropenem-resistant. Oxacillinases present were OXA-23-like, OXA-58-like and OXA-51-like, predominately in A. baumannii. NDM-1 was the dominant MBL (22% across different Acinetobacter spp. Isolates harbouring NDM-1 also possessed bla(VIM-2, PER-1, VEB-2, CTX-M-15, armA, aac(6’Ib, aac(6’Ib-cr genes. blaNDM-1 was organised in a composite transposon between two copies of ISAba125 in the isolates irrespective of the species. Further, OXA-23-like gene and OXA-58-like genes were linked with ISAba1 and ISAba3 respectively. Isolates were clonally diverse. Integrons were variable in sequence but not associated with carbapenem resistance. Most commonly found genes in the 5’ and 3’conserved segment were aminoglycoside resistance genes (aadB, aadA2, aac4’, non-enzymatic chloramphenicol resistance gene (cmlA1g and ADP-ribosylation genes (arr2, arr3. Outborn neonates had a significantly higher incidence of sepsis due to NDM-1 harbouring isolates than their inborn counterparts. This study

  10. Carbapenem Resistance in Acinetobacter baumannii and Other Acinetobacter spp. Causing Neonatal Sepsis: Focus on NDM-1 and Its Linkage to ISAba125

    Science.gov (United States)

    Chatterjee, Somdatta; Datta, Saswati; Roy, Subhasree; Ramanan, Lavanya; Saha, Anindya; Viswanathan, Rajlakshmi; Som, Tapas; Basu, Sulagna

    2016-01-01

    Carbapenem-resistant determinants and their surrounding genetic structure were studied in Acinetobacter spp. from neonatal sepsis cases collected over 7 years at a tertiary care hospital. Acinetobacter spp. (n = 68) were identified by ARDRA followed by susceptibility tests. Oxacillinases, metallo-β-lactamases (MBLs), extended-spectrum β-lactamases and AmpCs, were detected phenotypically and/or by PCR followed by DNA sequencing. Transconjugants possessing the blaNDM−1(New Delhi metallo-β-lactamase) underwent further analysis for plasmids, integrons and associated genes. Genetic environment of the carbapenemases were studied by PCR mapping and DNA sequencing. Multivariate logistic regression was used to identify risk factors for sepsis caused by NDM-1-harboring organisms. A. baumannii (72%) was the predominant species followed by A. calcoaceticus (10%), A. lwoffii (6%), A. nosocomialis (3%), A. junni (3%), A. variabilis (3%), A. haemolyticus (2%), and 14TU (2%). Fifty six percent of the isolates were meropenem-resistant. Oxacillinases present were OXA-23-like, OXA-58-like and OXA-51-like, predominately in A. baumannii. NDM-1 was the dominant MBL (22%) across different Acinetobacter spp. Isolates harboring NDM-1 also possessed bla(VIM−2, PER−1, VEB−2, CTX−M−15), armA, aac(6′)Ib, aac(6′)Ib-cr genes. blaNDM−1was organized in a composite transposon between two copies of ISAba125 in the isolates irrespective of the species. Further, OXA-23-like gene and OXA-58-like genes were linked with ISAba1 and ISAba3 respectively. Isolates were clonally diverse. Integrons were variable in sequence but not associated with carbapenem resistance. Most commonly found genes in the 5′ and 3′conserved segment were aminoglycoside resistance genes (aadB, aadA2, aac4′), non-enzymatic chloramphenicol resistance gene (cmlA1g) and ADP-ribosylation genes (arr2, arr3). Outborn neonates had a significantly higher incidence of sepsis due to NDM-1 harboring isolates than

  11. 醋酸钙-鲍曼不动杆菌复合体的精确鉴定与药敏分析%Species identification and antimicrobial susceptibility analysis of Acinetobacter calcoacelicus-Acinetobacter baumannii complex

    Institute of Scientific and Technical Information of China (English)

    聂璐; 白银磊; 李聪然; 游雪甫

    2013-01-01

    Objective To identify the exact species of Acinetobacter calcoacelicus-Acinetobacter baumannii complex and determine susceptibility of the isolates to aminoglycosides and carbapenems.Methods Species identification of clinical Acinetobacter spp.was performed using VITEK 2 instrument and isolates with Acinetobacter calcoacelicus-Acinetobacter baumannii complex results were further subjected to 16S rRNA sequence analysis identification.The susceptibility of Acinetobacter baumannii isolates and Acinetobacter calcoacelicus isolates to five antibiotics (amikacin,gentamicin,tobramycin,imipenem,ertapenem) was determined using VITEK 2 instrument or by mirodilution method,and the results were analyzed.Results Totally 232 Acinetobacter spp.was involved in species identification by VITEK 2 instrument,and 195 were identified as Acinetobacter calcoacelicus-Acinetobacter baumannii complex.Further species identification of the 195 Acinetobacter baumannii by 16S sequence analysis revealed that 173 isolates were Acinetobacter baumannii and 22 isolates were Acinetobacter calcoaceticus.Susceptibility testing of the 173 Acinetobacter baumannii and 22 Acinetobacter calcoacelicus to five antibiotics (amikacin,gentamicin,tobramycin,imipenem and ertapenem) were performed using VITEK 2 and by microdilution method respectively.The results with microdilution method demonstrated that 173 Acinetobacter baumannii were resistant to the three aminoglycosides,while relatively susceptible to the two carbapenems; 22 Acinetobacter calcoaceticus were susceptible to the three aminoglycosdes and two carbapenems,with susceptible rates of 77.27%-100%.As comparison to the results with microdilution method,the susceptibility results with VITEK 2 showed testing error of various degrees,with amikacin of the highest very major error rate (35.84%) in Acinetobacter baumannii susceptibility test and ertapenem of the highest major error rate (40.91%) in Acinetobacter calcoacelicus susceptibility test

  12. Acinetobacter: an underrated foodborne pathogen?

    Science.gov (United States)

    Amorim, Angelo Maximo Batista de; Nascimento, Janaína Dos Santos

    2017-02-28

    The increasing prevalence of foodborne diseases observed in developing countries has been linked to a rise in the consumption of raw foods. However, unlike the classical pathogens that are commonly implicated in foodborne illnesses, members of the genus Acinetobacter are rarely associated with diarrheal disease, probably because of the difficulty in isolating these Gram-negative bacteria from food sources. Nevertheless, several species of Acinetobacter, especially A. baumannii, possess many of the characteristics associated with successful pathogens and exhibit a prodigious ability to acquire the multiple-drug resistance (MDR) phenotype. In this mini-review, we summarize the epidemiological data relating to MDR Acinetobacter and consider evidence suggesting that contaminated dairy products, along with raw fruit and vegetables, constitute extra-hospital reservoirs of this underrated pathogen, and may represent an increased risk to immunocompromised individuals and young children in healthcare settings.

  13. Laboratory Maintenance of Acinetobacter baumannii.

    Science.gov (United States)

    Jacobs, Anna C; Zurawski, Daniel V

    2014-11-03

    Acinetobacter baumannii has recently drawn great interest in the microbiology research community due to the increase in clinical antibiotic resistance of this organism, and persistence of this bacterial species in the hospital environment. This unit outlines protocols for the growth and maintenance of A. baumannii in the laboratory.

  14. Substitutions of Ser83Leu in GyrA and Ser80Leu in ParC Associated with Quinolone Resistance in Acinetobacter pittii.

    Science.gov (United States)

    Gu, Dan-xia; Hu, Yun-jian; Zhou, Hong-wei; Zhang, Rong; Chen, Gong-xiang

    2015-06-01

    To investigate the prevalence and the mechanism of quinolone-resistant Acinetobacter pittii, 634 Acinetobacter calcoaceticus-Acinetobacter baumannii complex isolates were collected throughout Zhejiang Province. Identification of isolates was conducted by matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS), blaOXA-51-like gene, and partial RNA polymerase β-subunit (rpoB) amplification. Twenty-seven isolates of A. pittii were identified. Among the 634 isolates, A. baumannii, A. pittii, Acinetobacter nosocomialis, and A. calcoaceticus counted for 87.22%, 4.26%, 8.20%, and 0.32%, respectively. Antimicrobial susceptibility of nalidixic acid, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, levofloxacin, sparfloxacin, moxifloxacin, and gatifloxacin for 27 A. pittii were determined by the agar dilution method. Detection of quinolone-resistant determining regions of gyrA, gyrB, parC, and parE was performed for the A. pittii isolates. In addition, plasmid-mediated quinolone resistance (PMQR) determinants (qnrA, qnrB, qnrS, qnrC, qnrD, aac(6')-Ib-cr, qepA, oqxA, and oqxB) were investigated. All the 27 isolates demonstrated a higher minimum inhibitory concentration (MIC) to old quinolones than the new fluoroquinolones. No mutation in gyrA, gyrB, parC, or parE was detected in 20 ciprofloxacin-susceptible isolates. Seven ciprofloxacin-resistant A. pittii were identified with a Ser83Leu mutation in GyrA. Among them, six isolates with simultaneous Ser83Leu amino acid substitution in GyrA and Ser80Leu in ParC displayed higher MIC values against ciprofloxacin. Additionally, three were identified with a Met370Ile substitution in ParE, and two were detected with a Tyr317His mutation in ParE, which were reported for the first time. No PMQR determinants were identified in the 27 A. pittii isolates. In conclusion, mutations in chromosome play a major role in quinolone resistance in A. pittii, while resistance mechanisms mediated by plasmid have

  15. Comparison of the Virulence-Associated Phenotypes of Five Species of Acinetobacter baumannii Complex.

    Science.gov (United States)

    Na, In Young; Chung, Eun Seon; Jung, Chang-Yun; Kim, Dae Hun; Shin, Juyoun; Kang, KyeongJin; Kim, Seong-Tae; Ko, Kwan Soo

    2016-01-01

    In this study, we compared the virulence-associated factors of Acinetobacter baumannii complex species. Sixty-three isolates of five A. baumannii complex species, including 19 A. baumannii, 15 A. nosocomialis, 13 A. seifertii, 13 A. pittii, and 3 A. calcoaceticus isolates, were included in this study. For all isolates, biofilm formation, A549 cell adherence, resistance to normal human serum, and motility were evaluated. A. baumannii complex isolates showed diversity in biofilm formation, A549 cell adherence, and serum resistance, and no strong positive relationships among these virulence characteristics. However, A. seifertii showed relatively consistent virulence-associated phenotypes. In addition, A. baumannii clone ST110 exhibited consistently high virulence-associated phenotypes. Motility was observed in seven isolates, and all four A. baumannii ST110 isolates showed twitching motility. Although some inconsistencies in virulence-associated phenotypes were seen, high virulence characteristics were observed in A. seifertii, which has been mainly reported in Korea and shows high rates of colistin resistance.

  16. Reservoirs of Non-baumannii Acinetobacter Species

    OpenAIRE

    Ahmad eAl Atrouni; Monzer eHamze; Marie-Laure eJoly-Guillou; Marie eKEMPF

    2016-01-01

    Acinetobacter spp. are ubiquitous gram negative and non-fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non-baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described....

  17. Reservoirs of Non-baumannii Acinetobacter Species.

    Science.gov (United States)

    Al Atrouni, Ahmad; Joly-Guillou, Marie-Laure; Hamze, Monzer; Kempf, Marie

    2016-01-01

    Acinetobacter spp. are ubiquitous gram negative and non-fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non-baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described. In the present review, we summarize the recent data about the natural reservoir of non-baumannii Acinetobacter including the novel species that have been described for the first time from environmental sources and reported during the last years.

  18. Reservoirs of non-baumannii Acinetobacter species

    Directory of Open Access Journals (Sweden)

    Ahmad eAl Atrouni

    2016-02-01

    Full Text Available Acinetobacter spp are ubiquitous gram negative and non fermenting coccobacilli that have the ability to occupy several ecological niches including environment, animals and human. Among the different species, Acinetobacter baumannii has evolved as global pathogen causing wide range of infection. Since the implementation of molecular techniques, the habitat and the role of non baumannii Acinetobacter in human infection have been elucidated. In addition, several new species have been described. In the present review, we summarize the recent data about the natural reservoir of non-baumannii Acinetobacter including the novel species that have been described for the first time from environmental sources and reported during the last years.

  19. High prevalence of blaOXA-23 in Acinetobacter spp. and detection of blaNDM-1 in A. soli in Cuba: report from National Surveillance Program (2010–2012)

    Science.gov (United States)

    Quiñones, D.; Carvajal, I.; Perez, Y.; Hart, M.; Perez, J.; Garcia, S.; Salazar, D.; Ghosh, S.; Kawaguchiya, M.; Aung, M.S.; Kobayashi, N.

    2015-01-01

    As a first national surveillance of Acinetobacter in Cuba, a total of 500 Acinetobacter spp. isolates recovered from 30 hospitals between 2010 and 2012 were studied. Acinetobacter baumannii–calcoaceticus complex accounted for 96.4% of all the Acinetobacter isolates, while other species were detected at low frequency (A. junii 1.6%, A. lwoffii 1%, A. haemolyticus 0.8%, A. soli 0.2%). Resistance rates of isolates were 34–61% to third-generation cephalosporins, 49–50% to β-lactams/inhibitor combinations, 42–47% to aminoglycosides, 42–44% to carbapenems and 55% to ciprofloxacin. However, resistance rates to colistin, doxycycline, tetracycline and rifampin were less than 5%. Among carbapenem-resistant isolates, 75% harboured different blaOXA genes (OXA-23, 73%; OXA-24, 18%; OXA-58, 3%). The blaNDM-1 gene was identified in an A. soli strain, of which the species was confirmed by sequence analysis of 16S rRNA gene, rpoB, rpoB–rpoC and rpoL–rpoB intergenic spacer regions and gyrB. The sequences of blaNDM-1 and its surrounding genes were identical to those reported for plasmids of A. baumannii and A. lwoffi strains. This is the first report of blaNDM-1 in A. soli, together with a high prevalence of OXA-23 carbapenemase for carbapenem resistance in Acinetobacter spp. in Cuba. PMID:26236494

  20. High prevalence of blaOXA-23 in Acinetobacter spp. and detection of blaNDM-1 in A. soli in Cuba: report from National Surveillance Program (2010–2012

    Directory of Open Access Journals (Sweden)

    D. Quiñones

    2015-09-01

    Full Text Available As a first national surveillance of Acinetobacter in Cuba, a total of 500 Acinetobacter spp. isolates recovered from 30 hospitals between 2010 and 2012 were studied. Acinetobacter baumannii–calcoaceticus complex accounted for 96.4% of all the Acinetobacter isolates, while other species were detected at low frequency (A. junii 1.6%, A. lwoffii 1%, A. haemolyticus 0.8%, A. soli 0.2%. Resistance rates of isolates were 34–61% to third-generation cephalosporins, 49–50% to β-lactams/inhibitor combinations, 42–47% to aminoglycosides, 42–44% to carbapenems and 55% to ciprofloxacin. However, resistance rates to colistin, doxycycline, tetracycline and rifampin were less than 5%. Among carbapenem-resistant isolates, 75% harboured different blaOXA genes (OXA-23, 73%; OXA-24, 18%; OXA-58, 3%. The blaNDM-1 gene was identified in an A. soli strain, of which the species was confirmed by sequence analysis of 16S rRNA gene, rpoB, rpoB–rpoC and rpoL–rpoB intergenic spacer regions and gyrB. The sequences of blaNDM-1 and its surrounding genes were identical to those reported for plasmids of A. baumannii and A. lwoffi strains. This is the first report of blaNDM-1 in A. soli, together with a high prevalence of OXA-23 carbapenemase for carbapenem resistance in Acinetobacter spp. in Cuba.

  1. Carbapenem Susceptibility Testing Errors Using Three Automated Systems, Disk Diffusion, Etest, and Broth Microdilution and Carbapenem Resistance Genes in Isolates of Acinetobacter baumannii-calcoaceticus Complex

    Science.gov (United States)

    2016-06-07

    DISCUSSION ABC is an important nosocomial pathogen seen with in- creasing frequency throughout medical facilities . The ability of ABC to acquire extensive...settings because of their efficiency and convenience . However, the accuracy of automated methods for testing the susceptibilities of ABC isolates to

  2. Radiation resistance of acinetobacter spp.

    Science.gov (United States)

    Whitby, James L.

    1995-02-01

    The radiation resistance of 78 different strains of Acinetobacter sp. 42 from clinical isolates and 36 from other sources were compared with 15 clinical isolates and 12 other strains from Denmark. None of the Canadian strains was as resistant as resistant-enhanced Danish strains. Four strains had D 10 values of 3.1-3.6 kGy. Irradiated and unirradiated cells from all strains grew well, when cultured in Trypticase-Soy Broth at 30°C. Most cultures grew after overnight incubation. It was concluded that there would be no difficulty in detecting these strains, using ISO methodology for establishing the radiation sterilization dose for devices.

  3. A case of disseminated intravascular coagulation secondary to Acinetobacter lwoffii and Acinetobacter baumannii bacteremia

    OpenAIRE

    Candice Baldeo; Carmen Isache; Cherisse Baldeo; Abubakr Bajwa

    2015-01-01

    Bacteremia is currently one of the infections with the highest mortality in hospitals [1]. Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin [1]. Acinet...

  4. A case of disseminated intravascular coagulation secondary to Acinetobacter lwoffii and Acinetobacter baumannii bacteremia

    Directory of Open Access Journals (Sweden)

    Candice Baldeo

    2015-01-01

    Full Text Available Bacteremia is currently one of the infections with the highest mortality in hospitals [1]. Acinetobacter lwoffii and Acinetobacter baumannii are gram-negative bacteria and both represent opportunistic pathogens. In certain cases, the management can be challenging since these organisms can be highly resistant to antimicrobial agents. Clinical illnesses associated with Acinetobacter include pneumonia, meningitis, peritonitis, endocarditis and infections of the urinary tract and skin [1]. Acinetobacter bacteremia represents a serious and ever increasing problem because of the high associated morbidity and mortality.

  5. Sequence and organization of pMAC, an Acinetobacter baumannii plasmid harboring genes involved in organic peroxide resistance.

    Science.gov (United States)

    Dorsey, Caleb W; Tomaras, Andrew P; Actis, Luis A

    2006-09-01

    Acinetobacter baumannii 19606 harbors pMAC, a 9540-bp plasmid that contains 11 predicted open-reading frames (ORFs). Cloning and transformation experiments using Acinetobacter calcoaceticus BD413 mapped replication functions within a region containing four 21-bp direct repeats (ori) and ORF 1, which codes for a predicted replication protein. Subcloning and tri-parental mating experiments mapped mobilization functions to the product of ORF 11 and an adjacent predicted oriT. Three ORFs code for proteins that share similarity to hypothetical proteins encoded by plasmid genes found in other bacteria, while the predicted products of three others do not match any known sequence. The product of ORF 8 is similar to Ohr, a hydroperoxide reductase responsible for organic peroxide detoxification and resistance in bacteria. This ORF is immediately upstream of a coding region whose product is related to the MarR family of transcriptional regulators. Disk diffusion assays showed that A. baumannii 19606 is resistant to the organic peroxide-generating compounds cumene hydroperoxide (CHP) and tert-butyl hydroperoxide (t-BHP), although to levels lower than those detected in Pseudomonas aeruginosa PAO1. Cloning and introduction of the ohr and marR ORFs into Escherichia coli was associated with an increase in resistance to CHP and t-BHP. This appears to be the first case in which the genetic determinants involved in organic peroxide resistance are located in an extrachromosomal element, a situation that can facilitate the horizontal transfer of genetic elements coding for a function that protects bacterial cells from oxidative damage.

  6. Diversity of Acinetobacter baumannii in four French military hospitals, as assessed by multiple locus variable number of tandem repeats analysis.

    Directory of Open Access Journals (Sweden)

    Yolande Hauck

    Full Text Available BACKGROUND: Infections by A. calcoaceticus-A. baumannii (ACB complex isolates represent a serious threat for wounded and burn patients. Three international multidrug-resistant (MDR clones (EU clone I-III are responsible for a large proportion of nosocomial infections with A. baumannii but other emerging strains with high epidemic potential also occur. METHODOLOGY/PRINCIPAL FINDINGS: We automatized a Multiple locus variable number of tandem repeats (VNTR analysis (MLVA protocol and used it to investigate the genetic diversity of 136 ACB isolates from four military hospitals and one childrens hospital. Acinetobacter sp other than baumannii isolates represented 22.6% (31/137 with a majority being A. pittii. The genotyping protocol designed for A.baumannii was also efficient to cluster A. pittii isolates. Fifty-five percent of A. baumannii isolates belonged to the two international clones I and II, and we identified new clones which members were found in the different hospitals. Analysis of two CRISPR-cas systems helped define two clonal complexes and provided phylogenetic information to help trace back their emergence. CONCLUSIONS/SIGNIFICANCE: The increasing occurrence of A. baumannii infections in the hospital calls for measures to rapidly characterize the isolates and identify emerging clones. The automatized MLVA protocol can be the instrument for such surveys. In addition, the investigation of CRISPR/cas systems may give important keys to understand the evolution of some highly successful clonal complexes.

  7. Postcataract surgery endophthalmitis caused by acinetobacter lwoffii.

    Science.gov (United States)

    Roy, Rupak; Das, Debmalya; Kumar, Saurabh; Mukherjee, Anjan

    2015-01-01

    Acinetobacter lwoffii is a rare cause of endophthalmitis. We report a case of acute postoperative endophthalmitis in a female, who was treated successfully with pars plana vitrectomy and intravitreal antibiotics.

  8. Hemolytic uremic syndrome associated with Acinetobacter hemolyticus.

    Science.gov (United States)

    da Silva, Paulo Sérgio Lucas; Lipinski, Rubens Wolfe

    2014-08-01

    Shiga toxin-producing Escherichia coli and Shigella dysenteriae have been associated with bloody diarrhea and hemolytic uremic syndrome (HUS) in humans. However, there have been only a couple of reports describing bloody diarrhea associated with Acinetobacter spp. and there are no reports of these bacteria causing HUS in children. Here, we report the case of a nine-month-old boy with bloody diarrhea who developed non-oliguric renal failure. The clinical and laboratory findings supported the diagnosis of Acinetobacter hemolyticus infection associated with HUS. The patient responded favorably to antibiotic therapy plus conservative treatment. In conclusion, Acinetobacter infection should be considered as a plausible cause of HUS in cases where E. coli infection is not involved. The rapid transformation ability of Acinetobacter is a matter of concern.

  9. Biofilm formation in Acinetobacter baumannii.

    Science.gov (United States)

    Longo, Francesca; Vuotto, Claudia; Donelli, Gianfranco

    2014-04-01

    Acinetobacter baumannii has received much attention in recent years because of its increasing involvement in a number of severe infections and outbreaks occurring in clinical settings, and presumably related to its ability to survive and persist in hospital environments. The treatment of infections caused by A. baumannii nosocomial strains has become increasingly problematic, due to their intrinsic and/or acquired resistance to multiple classes of antibiotics. Furthermore, the demonstrated ability of nosocomial strains to grow as biofilm is believed to play a significant role in their persistence and antibiotic resistance. This review summarises current knowledge on A. baumannii biofilm formation and its clinical significance, as well as the related genetic determinants and the regulation of this process.

  10. Radiation resistance of Acinetobacter spp.

    Energy Technology Data Exchange (ETDEWEB)

    Whitby, J.L. [University of Western Ontario, London, ON (Canada)

    1995-10-01

    The radiation resistance of 78 different strains of Acinetobacter sp. 42 from clinical isolates and 36 from other sources were compared with 15 clinical isolates and 12 other strains from Denmark. None of the Canadian strains was as resistant as resistant-enhanced Danish strains. Four strains had D{sub 10} values of 3.1-3.6 kGy. Irradiated and unirradiated cells from all strains grew well, when cultured in Trypticase-Soy Broth at 30{sup o}C. Most cultures grew after overnight incubation. It was concluded that there would be no difficulty in detecting these strains, using ISO methodology for establishing the radiation sterilization dose for devices. (Author).

  11. Identification of NDM-1 in a Putatively Novel Acinetobacter Species ("NB14") Closely Related to Acinetobacter pittii.

    Science.gov (United States)

    Espinal, Paula; Mosqueda, Noraida; Telli, Murat; van der Reijden, Tanny; Rolo, Dora; Fernández-Orth, Dietmar; Dijkshoorn, Lenie; Roca, Ignasi; Vila, Jordi

    2015-10-01

    In this study, we describe the molecular characterization of a plasmid-located blaNDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. blaNDM-1 was carried by a conjugative plasmid widespread among non-baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species.

  12. High frequency of Acinetobacter soli among Acinetobacter isolates causing bacteremia at a tertiary hospital in Japan.

    Science.gov (United States)

    Endo, Shiro; Yano, Hisakazu; Kanamori, Hajime; Inomata, Shinya; Aoyagi, Tetsuji; Hatta, Masumitsu; Gu, Yoshiaki; Tokuda, Koichi; Kitagawa, Miho; Kaku, Mitsuo

    2014-03-01

    Acinetobacter baumannii is generally the most frequently isolated Acinetobacter species. Sequence analysis techniques allow reliable identification of Acinetobacter isolates at the species level. Forty-eight clinical isolates of Acinetobacter spp. were obtained from blood cultures at Tohoku University Hospital. These isolates were identified at the species level by partial sequencing of the RNA polymerase β-subunit (rpoB), 16S rRNA, and gyrB genes. Then further characterization was done by using the PCR for detection of OXA-type β-lactamase gene clusters, metallo-β-lactamases, and carO genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing were also performed. The most frequent isolate was Acinetobacter soli (27.1%). Six of the 13 A. soli isolates were carbapenem nonsusceptible, and all of these isolates produced IMP-1. PFGE revealed that the 13 A. soli isolates were divided into 8 clusters. This study demonstrated that A. soli accounted for a high proportion of Acinetobacter isolates causing bacteremia at a Japanese tertiary hospital. Non-A. baumannii species were identified more frequently than A. baumannii and carbapenem-nonsusceptible isolates were found among the non-A. baumannii strains. These results emphasize the importance of performing epidemiological investigations of Acinetobacter species.

  13. Clinical implications of glycoproteomics for Acinetobacter baumannii.

    Science.gov (United States)

    Kinsella, Rachel L; Scott, Nichollas E; Feldman, Mario F

    2015-02-01

    The opportunistic human pathogen Acinetobacter baumannii persists in the healthcare setting because of its ability to survive exposure to various antimicrobial and sterilization agents. A. baumannii's ability to cause multiple infection types complicates diagnosis and treatment. Rapid detection of A. baumannii infections would likely improve treatment outcomes. Recently published Acinetobacter glycoproteomic data show the prevalence of O-linked glycoproteins, suggesting the possibility for an O-glycan-based detection technology. O-glycan biosynthesis is required for protein glycosylation and capsular polysaccharide production in A. baumannii. Recent publications demonstrate key roles for protein glycosylation and capsular polysaccharide in the pathogenicity of A. baumannii. Targeted antimicrobial development against O-glycan biosynthesis may produce new effective treatment options for A. baumannii infections. Here, we discuss how the data gathered through Acinetobacter glycoproteomics can be used to develop technologies for rapid diagnosis and reveal potential antimicrobial targets. In addition, we consider the efficacy of glycoconjugate vaccine development against A. baumannii.

  14. NOSOCOMIAL ACINETOBACTER INFECTIONS IN INTENSIVE CARE UNIT

    Directory of Open Access Journals (Sweden)

    Nwadike V. Ugochukwu

    2013-01-01

    Full Text Available Acinetobacter plays an important role in the infection of patients admitted to hospitals. Acinetobacter are free living gram-negative coccobacilli that emerge as significant nosocomial pathogens in the hospital setting and are responsible for intermittent outbreaks in the Intensive Care Unit. The aim of this study was to determine the prevalence of Acinetobacter in patients admitted into the Intensive Care Unit and determine their role in infections in the ICU. A total of one hundred patients were recruited for the study, catheter specimen urine, tracheal aspirate and blood culture were collected aseptically from the patients. The specimens were cultured on blood and MacConkey and the organisms identified using Microbact 12E (0xoid. The Plasmid analysis was done using the TENS miniprep method. Fourteen (14% of the 100 patients recruited into the study, developed Acinetobacter infection. Acinetobacter spp constituted 9% of the total number of isolates. Twelve (86% of the isolates were recovered from tracheal aspirate, 1(7% from urine and 1(7% from blood. All of the isolates harbor plasmids of varying molecular sizes. Ten of the fourteen Acinetobacter were isolated at about the same period of time in the ICU with 6(42.7% having plasmid size in the 23.1kb band and all showed similar pattern revealing that the isolates exhibit some relatedness. The clonal nature of the isolates suggest that strict infection control practices must be adopted in ICU, also an antibiotic policy must be developed for the ICU to prevent abuse of antibiotics that may lead to selection of resistant bacteria.

  15. Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond.

    Science.gov (United States)

    Weber, Brent S; Harding, Christian M; Feldman, Mario F

    2015-12-28

    The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains.

  16. Antimicrobial resistance and clonality in Acinetobacter baumannii

    NARCIS (Netherlands)

    Nemec, Alexandr

    2009-01-01

    The aim of this thesis was to obtain insight into the epidemiology and molecular basis of multidrug resistance of Acinetobacter baumannii at the population level. To this aim a number of studies were performed on strains mainly from the Czech Republic (CR) which have shown in particular that (i) the

  17. A new double digestion ligation mediated suppression PCR method for simultaneous bacteria DNA-typing and confirmation of species: an Acinetobacter sp. model.

    Directory of Open Access Journals (Sweden)

    Karolina Stojowska

    Full Text Available We have designed a new ddLMS PCR (double digestion Ligation Mediated Suppression PCR method based on restriction site polymorphism upstream from the specific target sequence for the simultaneous identification and differentiation of bacterial strains. The ddLMS PCR combines a simple PCR used for species or genus identification and the LM PCR strategy for strain differentiation. The bacterial identification is confirmed in the form of the PCR product(s, while the length of the PCR product makes it possible to differentiate between bacterial strains. If there is a single copy of the target sequence within genomic DNA, one specific PCR product is created (simplex ddLMS PCR, whereas for multiple copies of the gene the fingerprinting patterns can be obtained (multiplex ddLMS PCR. The described ddLMS PCR method is designed for rapid and specific strain differentiation in medical and microbiological studies. In comparison to other LM PCR it has substantial advantages: enables specific species' DNA-typing without the need for pure bacterial culture selection, is not sensitive to contamination with other cells or genomic DNA, and gives univocal "band-based" results, which are easy to interpret. The utility of ddLMS PCR was shown for Acinetobacter calcoaceticus-baumannii (Acb complex, the genetically closely related and phenotypically similar species and also important nosocomial pathogens, for which currently, there are no recommended methods for screening, typing and identification. In this article two models are proposed: 3' recA-ddLMS PCR-MaeII/RsaI for Acb complex interspecific typing and 5' rrn-ddLMS PCR-HindIII/ApaI for Acinetobacter baumannii intraspecific typing. ddLMS PCR allows not only for DNA-typing but also for confirmation of species in one reaction. Also, practical guidelines for designing a diagnostic test based on ddLMS PCR for genotyping different species of bacteria are provided.

  18. Rapid species identification and epidemiological analysis of carbapenem-resistant Acinetobacter spp. by a PCR-based open reading frame typing method.

    Science.gov (United States)

    Yamada, Yuki; Endo, Kentaro; Sawase, Kaori; Anetai, Marie; Narita, Kazuya; Hatakeyama, Yuji; Ishifuji, Katsunori; Kurota, Makiko; Suwabe, Akira

    2016-09-01

    The spread of carbapenem-resistant Acinetobacter spp. has become a global problem. In this study, 18 carbapenem-resistant Acinetobacter calcoaceticus-baumannii (ACB) complexes, identified using a conventional biochemical method at our hospital during 2004-2013, were studied for species identification and epidemiological analyses. Species identification was performed using matrix-assisted laser desorption ionization-time-of-flight MS, a partial sequence analysis of rpoB and a PCR-based ORF typing (POT) method. The POT method can not only identify the species of ACB complexes but also simultaneously determine the international epidemic clones and the genetic identities of Acinetobacterbaumannii in several hours. Carbapenem resistance gene detection by PCR, molecular epidemiological analysis by PFGE and Pasteur Institute multilocus sequence typing (MLST) analysis were performed. All three methods identified 18 isolates as A. baumannii (n=10), Acinetobacterpittii (n=4) and Acinetobacternosocomialis (n=4). A metallo-β-lactamase gene in all strains of A. pittii and A. nosocomialis and an ISAba1 gene in the upstream of the blaOXA-51-like gene in eight strains of A. baumannii were detected, respectively, as carbapenemase-related genes. Results from PFGE demonstrated that nine strains of A. baumannii were closely related genetically. Results of MLST analysis showed that A. baumannii are classifiable to sequence type 2. These results were consistent with those obtained using the POT method. This POT method can easily and rapidly identify the international epidemic clones and the identities of A. baumannii. It can be a useful tool for infection control.

  19. Advances in diagnosis and treatment of pulmonary infection with Acinetobacter

    Directory of Open Access Journals (Sweden)

    Yi SHI

    2011-08-01

    Full Text Available Acinetobacter,especially Acinetobacter baumannii has emerged in recent years as a major cause of nosocomial infections,especially in intensive care units(ICUs,due to its multidrug-resistance(MDR even pan-drug-resistance(PDR characteristics.Acinetobacter infection may lead to high mortality,and it is serious and detrimental to patients.In the year 2009,CHINET antimicrobial surveillance showed that lung was the most commonly infected organ,and SENTRY antimicrobial surveillance showed that Acinetobacter had become the top fifth cause of hospital-acquired pneumonia(HAP,and its antibiotic resistance had gradually increased in these years.Colonization or infection of Acinetobacter should be determined at once when the bacteria were detected from culture of respiratory secretions.Generally,antibacterial treatment is not recommended if no clinical symptoms appear or imaging evidence unavailable.Since the resistance rate of Acinetobacter baumannii to most of the antibiotics reached 50% and above,an effective antibiotics should be carefully selected based on susceptibility test.Sulbactam or sulbactam-based composition is recommended for the carbapenem-resistant bacteria infection,particularly for infections caused by pan-resistant strains.As the first glycylcycline was approved to use in clinic,the anti-bacterial activity of Tigecycline against anti-carbapenem-resistant Acinetobacter has already been proven in vitro.In addition,the most important measure in controlling Acinetobacter pneumonia is to prevent the outbreak of Acinetobacter in medical institutions.

  20. Osteomyelitis in Military Personnel Wounded in Iraq and Afghanistan

    Science.gov (United States)

    2008-02-01

    of Osteomyelitis Initial Episode n 103 (%) Recurrence n 36 (%) Any gram-negative bacteria* 94 (91) 12 (33) Acinetobacter baumannii -calcoaceticus...indicates male; F, female; Abc, Acinetobacter baumannii -calcoaceticus complex; E. coli, Eschericia coli; P. aeruginosa, Pseudomonas aeruginosa; CNS...Gray PJ. Multidrug-resistant Acinetobacter extremity infections in soldiers. Emerg Infect Dis. 2005;11:1218–1224. 8. Acinetobacter baumannii infections

  1. Diversity of acinetobacter baumannii isolates from Egypt

    OpenAIRE

    Al-Hassan, Leena

    2013-01-01

    Acinetobacter baumannii is an important nosocomial pathogen, frequently associated with morbidity and mortality in immunocompromised patients due to the immuno-ablative treatments, neutropenia and prolonged hospitalization. The ability of A. baumannii to survive in the healthcare setting makes it a frequent problematic pathogen in cancer centres. Much of the interest in A. baumannii has been attributed to its remarkable rapid acquisition of resistance mechanisms A. baumannii is...

  2. Proteome Analysis of the Adaptation of a Phenol-Degrading Bacterium Acinetobacter sp. EDP3 to the Variation of Phenol Loadings%蛋白质组学方法分析不同苯酚浓度下菌株Acinetobacter sp.EDP3的应激机理

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Strain EDP3 was isolated from an industrial-activated sludge. It belonged to the gamma group of Proteobacteria with an identity of 97.0% to Acinetobacter calcoaceticus according to the 1 6S rRNA gene sequences. It can tolerate up to 1000mg.L-1 phenol at room temperature with a much longer lag phase. This indicates that higher phenol concentration has induced some physiological and genotypic changes in the bacterium. The aim of this study is,therefore,to investigate these responses to phenol concentration variations in strain EDP3. Proteome analysis is conducted by means of a two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was conducted to obtain a deeper insight into the adaptive responses inside the bacterium. Comparative analysis of the proteome profiles of strain EDp3 the higher phenol concentration,oxidative stress proteins were dominant. The synthesis of a heat shock protein,600O0 chaperonin GroEL,was also amplified. In addition,the expression of one membrane protein,adenosine 5'-triphosphate (ATP)-binding cassette (ABC) type sugar transporter,was found up-regulated. The inhibition of adenosine 5'-triphosphate (ATP) and RNA/protein synthesis was also observed.

  3. Quantitative proteomics to study carbapenem resistance in Acinetobacter baumannii.

    Science.gov (United States)

    Tiwari, Vishvanath; Tiwari, Monalisa

    2014-01-01

    Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create significant health problems and is responsible for high morbidity and mortality. With the development of quantitative proteomics, a considerable progress has been made in the study of carbapenem resistance of Acinetobacter baumannii. Recent updates showed that quantitative proteomics has now emerged as an important tool to understand the carbapenem resistance mechanism in Acinetobacter baumannii. Present review also highlights the complementary nature of different quantitative proteomic methods used to study carbapenem resistance and suggests to combine multiple proteomic methods for understanding the response to antibiotics by Acinetobacter baumannii.

  4. Quantitative Proteomics to study Carbapenem Resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Vishvanath eTiwari

    2014-09-01

    Full Text Available Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create significant health problems and is responsible for high morbidity & mortality. With the development of quantitative proteomics, a considerable progress has been made in the study of carbapenem resistance of Acinetobacter baumannii. Recent updates showed that quantitative proteomics has now emerged as an important tool to understand the carbapenem resistance mechanism in Acinetobacter baumannii. Present review also highlights the complementary nature of different quantitative proteomic methods used to study carbapenem resistance and suggests to combine multiple proteomic methods for understanding the response to antibiotics by Acinetobacter baumannii.

  5. Worldwide dissemination of acquired carbapenem-hydrolysing class D β-lactamases in Acinetobacter spp. other than Acinetobacter baumannii.

    Science.gov (United States)

    Zander, Esther; Fernández-González, Ana; Schleicher, Xenia; Dammhayn, Cathrin; Kamolvit, Witchuda; Seifert, Harald; Higgins, Paul G

    2014-04-01

    The aim of this study was to identify acquired OXA-type carbapenemases in Acinetobacter spp. other than Acinetobacter baumannii. From a total of 453 carbapenem-susceptible and -resistant Acinetobacter isolates collected worldwide, 23 were positive for blaOXA genes by multiplex PCR. These isolates were identified as Acinetobacter pittii (n=18), Acinetobacter nosocomialis (n=2), Acinetobacter junii (n=1) and Acinetobacter genomic species 14TU/13BJ (n=2). The blaOXA genes and associated insertion sequence (IS) elements were sequenced by primer walking. In 11 of these isolates, sequencing of the PCR products revealed that they were false-positive for blaOXA. The remaining 12 isolates, originating from Europe, Asia, South America, North America and South Africa, harboured OXA-23 (n=4), OXA-58 (n=5), OXA-40-like (n=1) and OXA-143-like (n=1); one A. pittii isolate harboured both OXA-23 and OXA-58. IS elements were associated with blaOXA in 10 isolates. OXA multiplex PCR showed a high degree of false-positive results (47.8%), indicating that detection of blaOXA in non-baumanniiAcinetobacter spp. should be confirmed using additional methods.

  6. Development of immunization trials against Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Tarek A. Ahmad

    2016-01-01

    Full Text Available Acinetobacter baumannii has recently crossed all lines once considered harmless, pushing its way as a nosocomial pathogen. It had acquired resistance to almost all available chemotherapies and mainly targets intensive care residents; causing pneumonia and major outbreaks with high mortality rates. This urged the need for preventive methods, which include infection control, non-specific immune-therapy, passive, and active immunization in order to offer vulnerable immune-compromised patients a flare in the dark. Several attempts were done for constructing effective vaccines with promising results. These are precisely classified, documented, and discussed in this up-to-date review.

  7. Characterization of blaOXA-143 variants in Acinetobacter baumannii and Acinetobacter pittii.

    Science.gov (United States)

    Zander, Esther; Bonnin, Rémy A; Seifert, Harald; Higgins, Paul G

    2014-05-01

    The acquired carbapenem-hydrolyzing oxacillinase (OXA) OXA-143 has thus far been detected only in Acinetobacter baumannii isolates from Brazil. The aim of this study was to characterize three OXA-143 variants: OXA-231 and OXA-253 from carbapenem-resistant A. baumannii isolates and OXA-255 in a carbapenem-susceptible Acinetobacter pittii isolate originating from Brazil, Honduras, and the United States, respectively. The 5' rapid amplification of cDNA ends (RACE) technique identified the same transcription initiation site for all blaOXA-143-like genes and revealed differences in the putative promoter regions. However, all cloned OXA-143 variants conferred carbapenem resistance on A. baumannii ATCC 17978 and OXA-255 conferred carbapenem resistance on A. pittii SH024, which was correlated with blaOXA-255 gene expression. This is the first description of OXA-143-like outside A. baumannii. Detection of OXA-143-like in the United States and Honduras indicates its dissemination through the American continent.

  8. Association of class 1 and 2 integrons with multidrug-resistant Acinetobacter baumannii international clones and Acinetobacter nosocomialis isolates.

    Science.gov (United States)

    Martins, Natacha; Picão, Renata Cristina; Adams-Sapper, Sheila; Riley, Lee W; Moreira, Beatriz Meurer

    2015-01-01

    The Acinetobacter baumannii clonal complex 113/79 (CC113/79) and class 2 integrons predominate in Latin America; a relationship between these characteristics was explored. The presence of integrases was determined in successive hospital Acinetobacter isolates (163 A. baumannii isolates and 72 Acinetobacter nosocomialis isolates). Most isolates had integrons, but class 1 and 2 integrons were present significantly more often in CC109/1 and CC113/79, respectively. The high prevalence of CC113/79 in Latin America may account for the predominance of class 2 integrons.

  9. Nanoparticles for Control of Biofilms of Acinetobacter Species

    Directory of Open Access Journals (Sweden)

    Richa Singh

    2016-05-01

    Full Text Available Biofilms are the cause of 80% of microbial infections. Acinetobacter species have emerged as multi- and pan-drug-resistant bacteria and pose a great threat to human health. These act as nosocomial pathogens and form excellent biofilms, both on biotic and abiotic surfaces, leading to severe infections and diseases. Various methods have been developed for treatment and control of Acinetobacter biofilm including photodynamic therapy, radioimmunotherapy, prophylactic vaccines and antimicrobial peptides. Nanotechnology, in the present scenario, offers a promising alternative. Nanomaterials possess unique properties, and multiple bactericidal mechanisms render them more effective than conventional drugs. This review intends to provide an overview of Acinetobacter biofilm and the significant role of various nanoparticles as anti-biofouling agents, surface-coating materials and drug-delivery vehicles for biofilm control and treatment of Acinetobacter infections.

  10. Systematic Review of Invasive Acinetobacter Infections in Children

    Directory of Open Access Journals (Sweden)

    Jia Hu

    2010-01-01

    Full Text Available INTRODUCTION: Clinicians are generally familiar with Acinetobacter as an etiological agent for serious nosocomial infections in intensive care units. However, there are no previous reviews of the full spectrum of invasive infections in children.

  11. A longitudinal study of Acinetobacter in three Australian hospitals.

    Science.gov (United States)

    Marshall, C; Richards, M; Black, J; Sinickas, V; Dendle, C; Korman, T; Spelman, D

    2007-11-01

    Acinetobacter has recently risen in prominence as a nosocomial pathogen, particularly due to increasing antibiotic resistance. The aim of this study was to describe changes in rates and antibiotic susceptibility patterns of Acinetobacter in three Melbourne hospitals. This was a retrospective review of microbiology records over five years. The rates of new clinical isolates of Acinetobacter per 10 000 discharges per quarter were calculated. Other information collected included antibiotic susceptibility patterns, age, gender, length of stay and ward [intensive care unit (ICU) or non-ICU]. Rates increased substantially at two hospitals, but not at the third. Increasing numbers at one hospital were associated with antibiotic resistance. Most first isolates were identified while the patient was in the ICU. Many isolates were from respiratory specimens, although a significant proportion was from blood. This study documents the establishment of Acinetobacter as a nosocomial pathogen in two Melbourne hospitals and serves as a warning for the future.

  12. Acinetobacter junii as an aetiological agent of corneal ulcer.

    Science.gov (United States)

    Broniek, G; Langwińska-Wośko, E; Szaflik, J; Wróblewska, M

    2014-12-01

    Rods of the Acinetobacter genus are present mainly in the external environment (e.g. water, soil) and in animals, while in humans they may comprise physiological flora. The main pathogenic species is Acinetobacter baumannii complex, which constitutes a common cause of nosocomial infections, particularly in patients with underlying diseases and risk factors (e.g. prior broad-spectrum antibiotic therapy, malignancy, central venous catheter, mechanical ventilation); however, infections of the eye caused by strains of Acinetobacter spp. are very rare. We report a unique case of community-acquired corneal ulcer caused by Acinetobacter non-baumannii (possibly A. junii), in a patient with no risk factors identified. The case highlights the need for obtaining a sample from the cornea for bacteriological culture in the case of suspected ophthalmic infection as identification of the pathogen, and assessment of its susceptibility profile enables proper antibiotic therapy, improves the outcome and may constitute an eyesight-saving management.

  13. A review of intravenous minocycline for treatment of multidrug-resistant Acinetobacter infections.

    Science.gov (United States)

    Ritchie, David J; Garavaglia-Wilson, Alexandria

    2014-12-01

    Options for treatment of multidrug-resistant (MDR) Acinetobacter baumannii infections are extremely limited. Minocycline intravenous is active against many MDR strains of Acinetobacter, and Clinical and Laboratory Standards Institute breakpoints exist to guide interpretation of minocycline susceptibility results with Acinetobacter. In addition, minocycline intravenous holds a US Food and Drug Administration indication for treatment of infections caused by Acinetobacter. There is an accumulating amount of literature reporting successful use of minocycline intravenous for treatment of serious MDR Acinetobacter infections, particularly for nosocomial pneumonia. These results, coupled with the generally favorable tolerability of minocycline intravenous, support its use as a viable therapeutic option for treatment of MDR Acinetobacter infections.

  14. Quantitative Proteomics to study Carbapenem Resistance in Acinetobacter baumannii

    OpenAIRE

    Vishvanath eTiwari; Monalisa eTiwari

    2014-01-01

    Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create signific...

  15. Quantitative proteomics to study carbapenem resistance in Acinetobacter baumannii

    OpenAIRE

    Tiwari, Vishvanath; Tiwari, Monalisa

    2014-01-01

    Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create signific...

  16. Mortality Audit of Neonatal Sepsis Secondary to Acinetobacter

    OpenAIRE

    Anuradha S De; Rathi, Madhuri R; Mathur, Meenakshi M

    2013-01-01

    Background: Multidrug resistant Acinetobacter infection has emerged as an important pathogen in neonatal sepsis in the recent years causing morbidity as well as mortality. Materials and Methods: A retrospective analysis was performed over a one and a half year period of all neonates admitted with sepsis in our neonatal intensive care unit (NICU), who developed Acinetobacter infection and to identify mortality-associated risk factors in these neonates. Results: Incidence of neonatal septicaemi...

  17. Prevalence of Aminoglycoside Resistance Genes in Acinetobacter baumannii Isolates

    OpenAIRE

    Aliakbarzade, Katayun; Farajnia, Safar; Karimi Nik, Ashraf; Zarei, Farzaneh; Tanomand, Asghar

    2014-01-01

    Background: Acinetobacter baumannii is one of the major causes of nosocomial infections and is resistant to most available antibiotics. Aminoglycosides remain as drugs of choice for treatment of Acinetobacter infections yet resistance to aminoglycosides has increased in the recent years. Objectives: The present study investigated the prevalence of genes encoding aminoglycoside-modifying enzymes in A. baumannii strains isolated from patients of Tabriz city, northwest of Iran. Materials and Met...

  18. Emerging Trend of Acinetobacter Nosocomial Infection in Northeast of Iran

    Directory of Open Access Journals (Sweden)

    Samaneh Saed

    2015-10-01

    Full Text Available Background: Acinetobacter spp. emerged as an opportunistic pathogen for hospital-acquired infections. Recently, increasing antibiotic resistance among Acinetobacter spp. has worsened the problem. The aim of this study was to investigate  the  emerging  trend  of  infection  due  to Acinetobacter  in Ghaem University Hospital, Mashhad during 2006-2012.Methods: The demographic data and information about redisposing factors was collected. Appropriate bacteriological samples were collected and Acinetobacter spp. was isolated. Antibiotics susceptibility pattern of these isolates againstdifferent antimicrobials agents was determined.Results: Results confirmed that Acinetobacter spp. cause 20.9% of nosocomial infection during this period. The trend of Acinetobacter nosocomial infection was increasing and patients with risk factors such as COPD, bronchectasia, diabetes   mellitus   were   more   prone   to   infection.  There   was   significant association   between   these   infections   and   invasive   procedures   such   as catheterization, mechanical ventilation and broad-spectrum antibiotics usage. Conclusion:  Understanding  trends  in  causative  organisms  of  nosocomial infection can help us to better define our infection control policy.

  19. Multidrug-Resistant Bacterial Colonization of Combat-Injured Personnel at Admission to Medical Centers After Evacuation from Afghanistan and Iraq

    Science.gov (United States)

    2011-07-01

    mul-tidrug-resistant [MDR] bacteria) infections, including those secondary to Acinetobacter baumannii -calcoaceticus complex, extended spectrum...REFERENCES 1. Scott P, Deye G, Srinivasan A, et al. An outbreak of multidrug-resistant Acinetobacter baumannii -calcoaceticus complex infection in the US...Hospenthal DR, Wortmann GW, Murray CK. Factors associated with recovery of Acinetobacter baumannii in a combat support hospital. Infect Control Hosp

  20. Bloodstream infection caused by extensively drug-resistant Acinetobacter baumannii in cancer patients: high mortality associated with delayed treatment rather than with the degree of neutropenia.

    Science.gov (United States)

    Freire, M P; de Oliveira Garcia, D; Garcia, C P; Campagnari Bueno, M F; Camargo, C H; Kono Magri, A S G; Francisco, G R; Reghini, R; Vieira, M F; Ibrahim, K Y; Rossi, F; Hajjar, L; Levin, A S; Hoff, P M; Pierrotti, L C; Abdala, E

    2016-04-01

    This study aimed to describe severe infections with extensively drug-resistant Acinetobacter baumannii-calcoaceticus complex (XDR-ABC), as well as to investigate risk factors for mortality, in cancer patients. It was a retrospective study including all patients diagnosed with XDR-ABC bacteraemia during hospitalization in the intensive care unit of a cancer hospital between July 2009 and July 2013. Surveillance cultures were collected weekly during the study period, and clonality was analysed using pulsed field gel electrophoresis (PFGE). We analysed underlying diseases, oncology therapy, neutrophil counts, infection site and management of infection, in terms of their correlation with 30-day mortality. During the study period, 92 patients with XDR-ABC bacteraemia were identified, of whom 35 (38.0%) were patients with haematological malignancy. We identified XDR-ABC strains with four different profile patterns, 91.3% of patients harbouring the predominant PFGE type. Of the 92 patients with XDR-ABC bacteraemia, 66 (71.7%) had central line-associated bloodstream infections; infection occurred during neutropenia in 22 (23.9%); and 58 (63.0%) died before receiving the appropriate therapy. All patients were treated with polymyxin, which was used in combination therapy in 30 of them (32.4%). The 30-day mortality rate was 83.7%. Multivariate analysis revealed that septic shock at diagnosis of XDR-ABC infection was a risk factor for 30-day mortality; protective factors were receiving appropriate therapy and invasive device removal within the first 48 h. Among cancer patients, ineffective management of such infection increases the risk of death, more so than do features such as neutropenia and infection at the tumour site.

  1. Genotypic analysis of Acinetobacter bloodstream infection isolates in a Turkish university hospital.

    NARCIS (Netherlands)

    Alp, E.; Esel, D.; Yildiz, O.; Voss, A.; Melchers, W.J.G.; Doganay, M.

    2006-01-01

    Acinetobacter baumannii is a significant pathogen of bloodstream infections in hospital patients that frequently causes single clone outbreaks. We aimed to evaluate the genetic relatedness and antimicrobial susceptibility of Acinetobacter spp. bloodstream isolates, in order to obtain insight into th

  2. Acinetobacter Baumannii in Intensive Care Units: prevention –nursing watch over

    OpenAIRE

    Mpitsiori Z

    2013-01-01

    Introduction: Acinetobacter Baumannii belongs to the large family of Acinetobacter, comes from the Greek word still, and for this reason it is called ‘Akinitovaktiridio’. Purpose: to review the recent literature on the genus Acinetobacter Baumannii in ICU and preventive measures against hospital infections. Methods: review from the Greek and foreign literature using keywords. Results: Acinetobacter ,during the last three decades , is of great interest in the medical community, because of the ...

  3. Multidrug-resistant Acinetobacter Infection Mortality Rate and Length of Hospitalization

    OpenAIRE

    Sunenshine, Rebecca H.; Wright, Marc-Oliver; Maragakis, Lisa L.; Harris, Anthony D.; Song, Xiaoyan; Hebden, Joan; Cosgrove, Sara E.; Anderson, Ashley; Carnell, Jennifer; Jernigan, Daniel B.; Kleinbaum, David G.; Perl, Trish M.; Standiford, Harold C.; Srinivasan, Arjun

    2007-01-01

    Acinetobacter infections have increased and gained attention because of the organism’s prolonged environmental survival and propensity to develop antimicrobial drug resistance. The effect of multidrug-resistant (MDR) Acinetobacter infection on clinical outcomes has not been reported. A retrospective, matched cohort investigation was performed at 2 Baltimore hospitals to examine outcomes of patients with MDR Acinetobacter infection compared with patients with susceptible Acinetobacter infectio...

  4. Acinetobacter Species Infections among Navy and Marine Corps Beneficiaries: 2012 Annual Report

    Science.gov (United States)

    2013-11-18

    January 2008. 2. Peleg, Anton; Harald Seifert and David Patterson. Acinetobacter baumannii : Emergence of a Successful Pathogen. Clinical Microbiology...Disease. 2(3): 291-304, 2010. 5. Perez, Federico et al. Minireview: Global Challenge of Multi-Drug Resistant Acinetobacter baumannii . Antimicrobial... Acinetobacter baumannii : Promising Theraputic Options for Treatment of Infection with Colisitin- Resistant Strains. Clinical Infectious Disease. 45: 594-598

  5. Clinical and economic outcomes of Acinetobacter vis a vis non-Acinetobacter infections in an Indian teaching hospital

    Directory of Open Access Journals (Sweden)

    Priyendu Asim

    2016-01-01

    Full Text Available Context: Acinetobacter infections are a major nosocomial infection causing epidemics of infection in the Intensive Care Units (ICU. Aims: This study estimates the clinical and economic outcomes of Acinetobacter infections and compares them with those of non-Acinetobacter bacterial infections. Settings and Design: Prospective cross-sectional observational study carried out for 6 months in the medicine ICU of a tertiary care hospital. Materials and Methods: Patients were divided in two groups, one group with Acinetobacter infections and the other with non-Acinetobacter infections. The data was collected for infection, length of stay (LOS, mortality and cost along with patient demographics from the hospital records for analysis. Statistical Analysis Used: The data was analyzed using Statistical Package for the Social Sciences Version 15.0. The LOS and cost of treatment (COT for the two groups were compared using the nonparametric Mann–Whitney U-test. Results: A total of 220 patients were studied out of which 91 had Acinetobacter infections. The median LOS was 20 days in Group-A and 12 days in Group-B (P < 0.0001. The median COT was INR 125,862 in Group-A and INR 68,228 in the Group-B (P < 0.0001. Mortality in Group-A and Group-B was 32.97 and 32.56 (P = 0.949 respectively. Conclusion: The burden of Acinetobacter infections in ICUs is increasing with the increase in LOS and COT for the patients. The infection control team has to play a major role in reducing the rate of nosocomial infections.

  6. Taxonomy of haemolytic and/or proteolytic strains of the genus Acinetobacter with the proposal of Acinetobacter courvalinii sp. nov. (genomic species 14 sensu Bouvet & Jeanjean), Acinetobacter dispersus sp. nov. (genomic species 17), Acinetobacter modestus sp. nov., Acinetobacter proteolyticus sp. nov. and Acinetobacter vivianii sp. nov.

    Science.gov (United States)

    Nemec, Alexandr; Radolfova-Krizova, Lenka; Maixnerova, Martina; Vrestiakova, Eliska; Jezek, Petr; Sedo, Ondrej

    2016-04-01

    We aimed to define the taxonomic status of 40 haemolytic and/or proteolytic strains of the genus Acinetobacter which were previously classified into five putative species termed as genomic species 14BJ (n=9), genomic species 17 (n=9), taxon 18 (n=7), taxon 19 (n=6) and taxon 20 (n=9). The strains were recovered mostly from human clinical specimens or soil and water ecosystems and were highly diverse in geographical origin and time of isolation. Comparative analysis of the rpoB and gyrB gene sequences of all strains, and the whole-genome sequences of selected strains, showed that these putative species formed five respective, well-supported clusters within a distinct clade of the genus Acinetobacter which typically, although not exclusively, encompasses strains with strong haemolytic activity. The whole-genome-based average nucleotide identity (ANIb) values supported the species status of each of these clusters. Moreover, the distinctness and coherence of the clusters were supported by whole-cell profiling based on MALDI-TOF MS. Congruent with these findings were the results of metabolic and physiological testing. We conclude that the five putative taxa represent respective novel species, for which the names Acinetobacter courvalinii sp. nov. (type strain ANC 3623T=CCUG 67960T=CIP 110480T=CCM 8635T), Acinetobacter dispersus sp. nov. (type strain ANC 4105T=CCUG 67961T=CIP 110500T=CCM 8636T), Acinetobacter modestus sp. nov. (type strain NIPH 236T=CCUG 67964T=CIP 110444T=CCM 8639T), Acinetobacter proteolyticus sp. nov. (type strain NIPH 809T=CCUG 67965T=CIP 110482T = CCM 8640T) and Acinetobacter vivianii sp. nov. (type strain NIPH 2168T=CCUG 67967T=CIP 110483T=CCM 8642T) are proposed.

  7. Acinetobacter baumannii: evolution of a global pathogen.

    Science.gov (United States)

    Antunes, Luísa C S; Visca, Paolo; Towner, Kevin J

    2014-08-01

    Acinetobacter baumannii is an opportunistic nosocomial pathogen and one of the six most important multidrug-resistant microorganisms in hospitals worldwide. This human pathogen is responsible for a vast array of infections, of which ventilator-associated pneumonia and bloodstream infections are the most common, and mortality rates can reach 35%. Community-acquired infections have also been reported, but few strains have been recovered from environmental sources and infection reservoirs external to the hospital have not been identified. The majority of A. baumannii infections are caused by two main population clones with worldwide distribution. Infection outbreaks are often associated with multidrug resistance, including the recent emergence of strains resistant to all available antibiotics. Nevertheless, A. baumannii virulence traits and pathogenic potential have mostly remained elusive. The recent expansion of A. baumannii sequenced genomes has permitted the development of large-array phylogenomic and phenotypic analyses, which can offer valuable insights into the evolution and adaptation of A. baumannii as a human pathogen. This review summarises these recent advances, with particular focus on A. baumannii evolutionary and genomic aspects, and proposes new avenues of research.

  8. Iron and Acinetobacter baumannii Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Valentina Gentile

    2014-08-01

    Full Text Available Acinetobacter baumannii is an emerging nosocomial pathogen, responsible for infection outbreaks worldwide. The pathogenicity of this bacterium is mainly due to its multidrug-resistance and ability to form biofilm on abiotic surfaces, which facilitate long-term persistence in the hospital setting. Given the crucial role of iron in A. baumannii nutrition and pathogenicity, iron metabolism has been considered as a possible target for chelation-based antibacterial chemotherapy. In this study, we investigated the effect of iron restriction on A. baumannii growth and biofilm formation using different iron chelators and culture conditions. We report substantial inter-strain variability and growth medium-dependence for biofilm formation by A. baumannii isolates from veterinary and clinical sources. Neither planktonic nor biofilm growth of A. baumannii was affected by exogenous chelators. Biofilm formation was either stimulated by iron or not responsive to iron in the majority of isolates tested, indicating that iron starvation is not sensed as an overall biofilm-inducing stimulus by A. baumannii. The impressive iron withholding capacity of this bacterium should be taken into account for future development of chelation-based antimicrobial and anti-biofilm therapies.

  9. A case of community-acquired Acinetobacter junii-johnsonii cellulitis.

    Science.gov (United States)

    Henao-Martínez, Andrés F; González-Fontal, Guido R; Johnson, Steven

    2012-06-01

    Acinetobacter skin and soft tissue infection outside of the traumatic wound setting are rare occurrences. The majority of cases occur in the presence of significant comorbilities and by Acinetobacter baumanii. Herein a case is reported of community-onset, health-care-associated, non-traumatic cellulitis caused by Acinetobacter, species junii-johnsonii with bacteremia. This is the first reported case of Acinetobacter junii-johnsonii skin and soft tissue infection. Hemorrhagic bullae might be one of the clinical features of Acinetobacter cellulitis.

  10. Morphine, but not trauma, sensitizes to systemic Acinetobacter baumannii infection.

    Science.gov (United States)

    Breslow, Jessica M; Monroy, M Alexandra; Daly, John M; Meissler, Joseph J; Gaughan, John; Adler, Martin W; Eisenstein, Toby K

    2011-12-01

    Acinetobacter baumannii is an important nosocomial pathogen in civilian intensive care units. Recently the incidence has increased in wounded military personnel. Morphine is documented in numerous animal studies to be immunosuppressive and to sensitize to infection. The hypotheses were tested that morphine, administered for analgesia in the battlefield, predisposes to Acinetobacter infection, and that the opioid may have an additive or synergistic effect with trauma. To test these hypotheses, an intraperitoneal infection model was established in mice using several Acinetobacter strains. Morphine administered for 48 h by implantation of a slow-release morphine pellet increased mortality compared to animals receiving a placebo pellet, an effect that was blocked by the mu-opioid receptor antagonist, naltrexone. Acinetobacter burdens in the blood, spleens, livers, and lungs of morphine-treated mice, were significantly higher than those in placebo-treated animals, confirming that mortality was due to potentiated growth of the bacteria. There were also elevated levels of pro-inflammatory cytokines in morphine-treated versus placebo-treated mice. Morphine caused a reduction in the total number of cells in the peritoneal cavity, a decrease in the percentage and total numbers of neutrophils, and a decrease in the total number of macrophages. Morphine treatment also suppressed levels of the neutrophil-inducing molecules, IL-17A and KC/CXCL1. However, IL-17A(-/-) mice given morphine were not sensitized to Acintobacter infection to a greater degree than similarly treated wild-type mice. Trauma alone did not sensitize to Acinetobacter infection, and there was no additive effect between morphine and trauma. These results support the hypothesis that morphine potentiates Acinetobacter infection.

  11. Acinetobacter septicemia in neonates admitted to intensive care units

    Directory of Open Access Journals (Sweden)

    Vishal B Shete

    2009-01-01

    Results: A total of 26 Acinetobacter septicemia cases were identified by blood culture. Acb complex strains predominated. Institutional birth and preterm birth were identified as the most frequent significant risk factors. 11.3% mortality rate was recorded. Acb complex strains exhibited a multi-drug resistant pattern. No carbapenem resistance was observed. Conclusion: Acinetobacter should be added to the list of organisms causing severe nosocomial infection in neonatal intensive care units. Continuous bacteriological surveillance, implementation of infection control policies, careful disinfection of intensive care equipment, and rational antibiotic use are required for control of such infections.

  12. Regulation of Acinetobacter baumannii biofilm formation.

    Science.gov (United States)

    Gaddy, Jennifer A; Actis, Luis A

    2009-04-01

    Acinetobacter baumannii is a Gram-negative opportunistic nosocomial pathogen. This microorganism survives in hospital environments despite unfavorable conditions such as desiccation, nutrient starvation and antimicrobial treatments. It is hypothesized that its ability to persist in these environments, as well as its virulence, is a result of its capacity to form biofilms. A. baumannii forms biofilms on abiotic surfaces such as polystyrene and glass as well as biotic surfaces such as epithelial cells and fungal filaments. Pili assembly and production of the Bap surface-adhesion protein play a role in biofilm initiation and maturation after initial attachment to abiotic surfaces. Furthermore, the adhesion and biofilm phenotypes of some clinical isolates seem to be related to the presence of broad-spectrum antibiotic resistance. The regulation of the formation and development of these biofilms is as diverse as the surfaces on which this bacterium persists and as the cellular components that participate in this programmed multistep process. The regulatory processes associated with biofilm formation include sensing of bacterial cell density, the presence of different nutrients and the concentration of free cations available to bacterial cells. Some of these extracellular signals may be sensed by two-component regulatory systems such as BfmRS. This transcriptional regulatory system activates the expression of the usher-chaperone assembly system responsible for the production of pili, needed for cell attachment and biofilm formation on polystyrene surfaces. However, such a system is not required for biofilm formation on abiotic surfaces when cells are cultured in chemically defined media. Interestingly, the BfmRS system also controls cell morphology under particular culture conditions.

  13. Contribution of Acinetobacter-derived cephalosporinase-30 to sulbactam resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Shu-Chen eKuo

    2015-03-01

    Full Text Available The sulbactam resistance rate in Acinetobacter baumannii has increased worldwide. Previous reports have shown that the β-lactamase blaTEM-1 confers resistance to sulbactam in A. baumannii. The purpose of this study was to examine whether other β-lactamases including, the Acinetobacter-derived cephalosporinase (ADC, OXA-23, OXA-24/72, and OXA-58 families, also contribute to sulbactam resistance in A. baumannii. The correlation between these β-lactamases and the sulbactam minimal inhibitory concentration (MIC was determined using A. baumannii clinical isolates from diverse clonality, which were collected in a nationwide surveillance program from 2002 to 2010 in Taiwan. A possible association between the genetic structure of ISAba1-blaADC-30 and sulbactam resistance was observed because this genetic structure was detected in 97% of sulbactam-resistant strains compared with 10% of sulbactam-susceptible strains. Transformation of ISAba1-blaADC-30 into susceptible strains increased the sulbactam MIC from 2 to 32 μg/ml, which required blaADC-30 overexpression using an upstream promoter in ISAba1. Flow cytometry showed that ADC-30 production increased in response to sulbactam, ticarcillin, and ceftazidime treatment. This effect was regulated at the RNA level but not by an increase in the blaADC-30 gene copy number as indicated by quantitative PCR. Purified ADC-30 decreased the inhibitory zone created by sulbactam or ceftazidime, similarly to TEM-1. In conclusion, ADC-30 overexpression conferred resistance to sulbactam in diverse clinical A. baumannii isolates.

  14. Confronting multidrug-resistant Acinetobacter baumannii: a review.

    Science.gov (United States)

    Neonakis, Ioannis K; Spandidos, Demetrios A; Petinaki, Efthimia

    2011-02-01

    Multidrug-resistant Acinetobacter baumannii (MDR-AB) infections are difficult to treat owing to the extremely limited armamentarium. The present review reports all available treatment options against MDR-AB, including single molecules, combination schemes, and alternative modes of antimicrobial administration. Additionally, a group of recently reported peptides with anti-MDR-AB activity is described.

  15. Carbapenem-resistant Acinetobacter baumannii: epidemiology, surveillance and management.

    Science.gov (United States)

    Pogue, Jason M; Mann, Tal; Barber, Katie E; Kaye, Keith S

    2013-04-01

    Carbapenem-resistant Acinetobacter baumannii pose a significant threat to hospitalized patients, as therapeutic options are scarse. Alarmingly, rates of carbapenem-resistance in A. baumannii are on the rise and are slowly becoming a routine phenotype for this organism. This review focuses on infection control strategies for identification and control of A. baumannii, as well the available therapeutic options.

  16. Acinetobacter plantarum sp. nov. isolated from wheat seedlings plant.

    Science.gov (United States)

    Du, Juan; Singh, Hina; Yu, Hongshan; Jin, Feng-Xie; Yi, Tae-Hoo

    2016-07-01

    Strain THG-SQM11(T), a Gram-negative, aerobic, non-motile, coccus-shaped bacterium, was isolated from wheat seedlings plant in P. R. China. Strain THG-SQM11(T) was closely related to members of the genus Acinetobacter and showed the highest 16S rRNA sequence similarities with Acinetobacter junii (97.9 %) and Acinetobacter kookii (96.1 %). DNA-DNA hybridization showed 41.3 ± 2.4 % DNA reassociation with A. junii KCTC 12416(T). Chemotaxonomic data revealed that strain THG-SQM11(T) possesses ubiquinone-9 as the predominant respiratory quinone, C18:1 ω9c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C16:0 as the major fatty acids. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. The DNA G+C content was 41.7 mol %. These data, together with phenotypic characterization, suggest that the isolate represents a novel species, for which the name Acinetobacter plantarum sp. nov. is proposed, with THG-SQM11(T) as the type strain (=CCTCC AB 2015123(T) =KCTC 42611(T)).

  17. [Activity of doripenem against Pseudomonas spp. and Acinetobacter spp. rods].

    Science.gov (United States)

    Bogiel, Tomasz; Deptuła, Aleksander; Gospodarek, Eugenia

    2009-01-01

    Doripenem, the newest carbapenem was approved in 2008 by the European Medicines Agency for the treatment of complicated intra-abdominal infections and complicated urinary tract infections. Its spectrum of activity is similar to that of meropenem and imipenem/cilastatin. The aim of this study was to compare in vitro activity of doripenem against nonfermentative Gram-negative rods. A total of 235 strains of Pseudomonas spp. (74.9%) and Acinetobacter spp. (25.1%) were included into the study. Strains were isolated in The Department of Clinical Microbiology of the University Hospital No 1 in Bydgoszcz and identified using ID GN tests (bioMérieux). To determine susceptibility to doripenem and other carbapenems disc-diffusion method was applied. Percentage of doripenem resistant strains reached 28.4% and 39.0% for Pseudomonas spp. and Acinetobacter spp, respectively. All doripenem sensitive or intermediate Acinetobacter spp. strains were simultaneously sensitive to imipenem and meropenem. Activity of imipenem and meropenem among doripenem resistant Acinetobacter spp. were represented by 60.9% and 56.5% strains, respectively. Activity of imipenem and meropenem among doripenem resistant Pseudomonas spp. strains were represented by 12.0% and 18.0%, respectively. Occurence of one doripenem sensitive Pseudomonas spp. strain simultaneously resistant to imipenem and meropenem was observed.

  18. Acinetobacter species in the hospital environment : tracing and epidemiology.

    NARCIS (Netherlands)

    L. Dijkshoorn-de Bruin (Lenie)

    1990-01-01

    textabstractIn the course of the investigation a new taxonomic classification of Acinetobacter strains was introduced. The groups of this classification were established on the basis of DNA-DNA hybridization data of strains. In a final study of the present thesis, we investigated whether cell envelo

  19. A Pathogenic Potential of Acinetobacter baumannii-Derived Membrane Vesicles

    Directory of Open Access Journals (Sweden)

    Jong Suk Jin

    2011-12-01

    Full Text Available Acinetobacter baumannii secretes outer membrane vesicles (OMVs. A. baumannii OMVs deliver many virulence factors to host cells and then induce cytotoxicity and innate immune response. OMVs secreted from bacteria contribute directly to host pathology during A. baumannii infection.

  20. Acinetobacter infection--an emerging threat to human health.

    Science.gov (United States)

    Visca, Paolo; Seifert, Harald; Towner, Kevin J

    2011-12-01

    The genus Acinetobacter comprises a complex and heterogeneous group of bacteria, many of which are capable of causing a range of opportunistic, often catheter-related, infections in humans. However, Acinetobacter baumannii, as well as its close relatives belonging to genomic species 3 ("Acinetobacter pittii") and 13TU ("Acinetobacter nosocomialis"), are important nosocomial pathogens, often associated with epidemic outbreaks of infection, that are only rarely found outside of a clinical setting. These organisms are frequently pandrug-resistant and are capable of causing substantial morbidity and mortality in patients with severe underlying disease, both in the hospital and in the community. Several epidemic clonal lineages of A. baumannii have disseminated worldwide and seem to have a selective advantage over non-epidemic strains. The reasons for the success of these epidemic lineages remain to be elucidated, but could be related to the potential of these organisms to achieve very dynamic reorganization and rapid evolution of their genome, including the acquisition and expression of additional antibiotic resistance determinants, under fluctuating environmental and selective conditions.

  1. Acinetobacter indicus sp. nov., isolated from a hexachlorocyclohexane dump site.

    Science.gov (United States)

    Malhotra, Jaya; Anand, Shailly; Jindal, Swati; Rajagopal, Raman; Lal, Rup

    2012-12-01

    The taxonomic position of a Gram-negative, non-motile, oxidase negative and catalase positive strain, A648(T), isolated from a hexachlorocyclohexane (HCH) dump site located in Lucknow, India, was ascertained by using a polyphasic approach. A comparative analysis of a partial sequence of the rpoB gene and the 16S rRNA gene sequence revealed that strain A648(T) belonged to the genus Acinetobacter. DNA-DNA relatedness values between strain A648(T) and other closely related members (16S rRNA gene sequence similarity greater than 97%), namely Acinetobacter radioresistens DSM 6976(T), A. venetianus ATCC 31012(T), A. baumannii LMG 1041(T), A. parvus LMG 21765(T) A. junii LMG 998(T) and A. soli JCM 15062(T), were found to be less than 8%. The major cellular fatty acids of strain A648(T) were 18:1ω9c (19.6%), summed feature 3 (15.9%), 16:0 (10.6%) and 12:0 (6.4%). The DNA G+C content was 40.4 mol%. The polar lipid profile of strain A648(T) indicated the presence of diphosphatidylglycerol, phosphatidylethanolamine, followed by phosphatidylglycerol and phosphatidylcholine. The predominant polyamine of strain A648(T) was 1,3-diaminopropane and moderate amounts of putrescine, spermidine and spermine were also detected. The respiratory quinone consisted of ubiquinone with nine isoprene units (Q-9). On the basis of DNA-DNA hybridization, phenotypic characteristics and chemotaxonomic and phylogenetic comparisons with other members of the genus Acinetobacter, strain A648(T) is found to be a novel species of the genus Acinetobacter, for which the name Acinetobacter indicus sp. nov. is proposed. The type strain is A648(T) ( = DSM 25388(T) = CCM 7832(T)).

  2. Characterization of Acinetobacter baumannii biofilm associated components

    Science.gov (United States)

    Brossard, Kari A.

    Acinetobacter baumannii is a Gram-negative aerobic coccobaccillus that is a major cause of nosocomial infections worldwide. Infected individuals may develop pneumonia, urinary tract, wound, and other infections that are associated with the use of indwelling medical devices such as catheters and mechanical ventilation. Treatment is difficult because many A. baumannii isolates have developed multi-drug resistance and the bacterium can persist on abiotic surfaces. Persistence and resistance may be due to formation of biofilms, which leads to long-term colonization, evasion of the host immune system and resistance to treatment with antibiotics and disinfectants. While biofilms are complex multifaceted structures, two bacterial components that have been shown to be important in formation and stability are exopolysaccharides (EPS) and the biofilm-associated protein (Bap). An EPS, poly-beta-1,6-N-acetylglucosamine, PNAG, has been described for E. coli and S. epidermidis. PNAG acts as an intercellular adhesin. Production of this adhesin is dependent on the pga/icaABCD locus. We have identified a homologous locus in A. baumannii 307-0294 that is involved in production of an exopolysaccharide, recognized by an anti-PNAG antibody. We hypothesized that the A. baumannii pgaABCD locus plays a role in biofilm formation, and protection against host innate defenses and disinfectants suggesting that PNAG is a possible virulence factor for the organism. The first aim of this thesis will define the pgaABCD locus. We have previously identified Bap, a protein with similarity to those described for S. aureus and we have demonstrated that this protein is involved in maintaining the stability of biofilms on glass. We hypothesized that A. baumannii Bap plays a role in persistence and pathogenesis and is regulated by quorum sensing. In our second aim we will examine the role of Bap in attachment and biofilm formation on medically relevant surfaces and also determine if Bap is involved in

  3. Multidrug-Resistant Gram-Negative Bacteria Colonization of Healthy US Military Personnel in the US and Afghanistan

    Science.gov (United States)

    2013-02-05

    7 (7) 27 (35) 65 (99) 85 (188) Acinetobacter baumannii -calcoaceticus complex 0 1 (1) 0 0 1 (1) 4 (4) 2 (2) 8 (8) Acinetobacter lwoffii 0 1 (1) 0 1...0 1 0.50 Perirectal 2 9 0.03 All bacteria Acinetobacter baumannii -calcoaceticus complex 8 4 0.24 Acinetobacter lwoffii 8 13 0.24... baumannii - calcoaceticus complex 0 0 0 0 1 (1) 3 (3) 0 4 (4) Acinetobacter lwoffii 0 0 3 (3) 2 (2) 5 (5) 5 (5) 1 (1) 13 (16) Alcaligenes species 0 1

  4. The activity of silver nanoparticles (Axonnite) on clinical and environmental strains of Acinetobacter spp.

    Science.gov (United States)

    Łysakowska, Monika E; Ciebiada-Adamiec, Anna; Klimek, Leszek; Sienkiewicz, Monika

    2015-03-01

    Acinetobacter baumannii isolates are responsible for a high number of wound infections. The reason of this study was to evaluate the activity of silver nanoparticles obtained by microexplosion against wide range of Acinetobacter spp. Susceptibility to silver nanoparticles was tested by microdilution method, susceptibility to antibiotics was evaluated by the disc-diffusion method. All strains of Acinetobacter spp. were sensitive to AgNPs at low concentrations. The values of the MIC for strains of Acinetobacter spp. were 0.39 and 0.78μg/mL. In general, strains inhibited by 0.78μg/mL of AgNPs were more resistant to antibiotics than Acinetobacter strains for which MIC=0.39μg/mL (p=0.023). The AgNPs in Axonnite seems to be a good alternative for other antimicrobials to treat wound infections caused by multidrug resistant Acinetobacter spp. strains because of its high activity.

  5. Unusual features of the sequences of copies of the 16S-23S rRNA internal transcribed spacer regions of Acinetobacter bereziniae, Acinetobacter guillouiae and Acinetobacter baylyi arise from horizontal gene transfer events.

    Science.gov (United States)

    Maslunka, Christopher; Gürtler, Volker; Seviour, Robert

    2015-02-01

    The highly variable nature of the internal transcribed spacer region (ITS) has been claimed to represent an ideal target for designing species-specific probes/primers capable of differentiating between closely related Acinetobacter species. However, several Acinetobacter species contain multiple ITS copies of variable lengths, and these include Acinetobacter bereziniae, Acinetobacter guillouiae and Acinetobacter baylyi. This study shows these length variations result from inter-genomic insertion/deletion events (indels) involving horizontal transfer of ITS fragments of other Acinetobacter species and possibly unrelated bacteria, as shown previously by us. In some instances, indel incorporation results in the loss of probe target sites in the recipient cell ITS. In other cases, some indel sequences contain target sites for probes designed from a single ITS sequence to target other Acinetobacter species. Hence, these can generate false positives. The largest of the indels that remove probe sites is 683 bp (labelled bay/i1-0), and it derives from the horizontal transfer of a complete ITS between A. bereziniae BCRC15423(T) and A. baylyi strain ADP1. As a consequence, ITS sequencing or fingerprinting cannot be used to distinguish between the 683 bp ITS in these two strains.

  6. Acinetobacter baumannii Septicemia in a Recipient of an Allogeneic Hematopoietic Stem Cell Transplantation

    Science.gov (United States)

    Al-Anazi, Khalid Ahmed; Abdalhamid, Baha; Alshibani, Zeyad; Awad, Khalid; Alzayed, Abdullah; Hassan, Hoda; Alsayiegh, Mohammed

    2012-01-01

    Acinetobacter baumannii is a gram-negative, nonfermentative coccobacillus that causes infections in immunocompromised and chronically ill patients and is associated with multidrug resistance. Two days before receiving her nonmyeloablative stem cell allograft, a patient with acute myeloid leukemia developed Acinetobacter baumannii bacteremia that caused septic shock which was successfully treated with imipenem and removal of the central venous catheter. To our knowledge, this is the first report of Acinetobacter baumannii septicemia in a hematopietic stem cell transplantation recipient. PMID:23259136

  7. Molecular Epidemiology of Aminoglycosides Resistance in Acinetobacter Spp. with Emergence of Multidrug-Resistant Strains

    OpenAIRE

    MH Nazem Shirazi; Gh Shajari; R Kheltabadi Farahani; R Moniri; A Ghasemi

    2010-01-01

    Background: Acinetobacter spp. is characterized as an important nosocomial pathogen and increasing antimicrobial resistance. Our aim was to evaluate antimicrobial susceptibility and aminoglycosides resistance genes of Acinetobacter spp. isolated from hospitalized patients. Methods: Sixty isolates were identified as Acinetobacter species. The isolates were tested for antibiotic resistance by disc diffusion method for 12 antimicrobials. The presence of aphA6, aacC1 aadA1, and aadB genes were de...

  8. Acinetobacter gandensis sp. nov. isolated from horse and cattle.

    Science.gov (United States)

    Smet, Annemieke; Cools, Piet; Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Haesebrouck, Freddy; Kempf, Marie; Nemec, Alexandr; Vaneechoutte, Mario

    2014-12-01

    We previously reported the presence of an OXA-23 carbapenemase in an undescribed species of the genus Acinetobacter isolated from horse dung at the Faculty of Veterinary Medicine, Ghent University, Belgium. Here we include six strains to corroborate the delineation of this taxon by phenotypic characterization, DNA-DNA hybridization, 16S rRNA gene and rpoB sequence analysis, % G+C determination, MALDI-TOF MS and fatty acid analysis. The nearly complete 16S rRNA gene sequence of strain UG 60467(T) showed the highest similarities with those of the type strains of Acinetobacter bouvetii (98.4 %), Acinetobacter haemolyticus (97.7 %), and Acinetobacter schindleri (97.2 %). The partial rpoB sequence of strain UG 60467(T) showed the highest similarities with 'Acinetobacter bohemicus' ANC 3994 (88.6 %), A. bouvetii NIPH 2281 (88.6 %) and A. schindleri CIP 107287T (87.3 %). Whole-cell MALDI-TOF MS analyses supported the distinctness of the group at the protein level. The predominant fatty acids of strain UG 60467(T) were C12 : 0 3-OH, C12 : 0, C16 : 0, C18 : 1ω9c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). Strains UG 60467(T) and UG 60716 showed a DNA-DNA relatedness of 84 % with each other and a DNA-DNA relatedness with A. schindleri LMG 19576(T) of 17 % and 20 %, respectively. The DNA G+C content of strain UG 60467(T) was 39.6 mol%. The name Acinetobacter gandensis sp. nov. is proposed for the novel taxon. The type strain is UG 60467(T) ( = ANC 4275(T) = LMG 27960(T) = DSM 28097(T)).

  9. NCBI nr-aa BLAST: CBRC-TTRU-01-0810 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TTRU-01-0810 ref|ZP_06056093.1| DMT family permease [Acinetobacter calcoacetic...us RUH2202] gb|EEY77392.1| DMT family permease [Acinetobacter calcoaceticus RUH2202] ZP_06056093.1 0.16 27% ...

  10. NCBI nr-aa BLAST: CBRC-PCAP-01-0812 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-PCAP-01-0812 ref|ZP_06057936.1| ribonucleotide reductase [Acinetobacter calcoa...ceticus RUH2202] gb|EEY79235.1| ribonucleotide reductase [Acinetobacter calcoaceticus RUH2202] ZP_06057936.1 4.5 38% ...

  11. Genetic tools for manipulating Acinetobacter baumannii genome: an overview.

    Science.gov (United States)

    Biswas, Indranil

    2015-07-01

    Acinetobacter baumannii is an emerging nosocomial pathogen involved in a variety of infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteraemia. A. baumannii has become resistant to most of the commonly used antibiotics and multidrug-resistant isolates are becoming a severe problem in the healthcare setting. In the past few years, whole-genome sequences of >200 A. baumannii isolates have been generated. Several methods and molecular tools have been used for genetic manipulation of various Acinetobacter spp. Here, we review recent developments of various genetic tools used for modification of the A. baumannii genome, including various ways to inactivate gene function, chromosomal integration and transposon mutagenesis.

  12. Two case reports of gastroendoscopy-associated Acinetobacter baumannii bacteremia

    OpenAIRE

    Chen, Chang-Hua; Wu, Shun-Sheng; Huang, Chieh-Chen

    2013-01-01

    Two cases of gastroendoscopy-associated Acinetobacter baumannii (A. baumannii) bacteremia were discovered at the study hospital. The first case was a 66-year-old woman who underwent endoscopic retrograde cholangiopancreatography and endoscopic retrograde papillotomy, and then A. baumannii bacteremia occurred. The second case was a 70-year-old female who underwent endoscopic retrograde biliary drainage due to obstruction of intra-hepatic ducts, and bacteremia occurred due to polymicrobes (Esch...

  13. Proteomic insights into Acinetobacter baumannii drug resistance and pathogenesis.

    Science.gov (United States)

    Long, Quanxin; Huang, Changwu; Liao, Pu; Xie, Jianping

    2013-01-01

    Acinetobacter baumannii is an important opportunist pathogen, due to severe antibiotic resistance and nosocomial infection. The epidemiology and antibiotic resistance of A.baumannii have been extensively reviewed, but the pathogenesis and virulence remain unclear. Proteomics analysis has been applied to study the mechanism of drug resistance, biofilm, micronutrient acquisition, and the extracellular compartment. This review summarizes applications of proteomics in A. baumannii, aiming to summarize novel insights into the mechanism of A. baumannii pathogenesis and drug resistance.

  14. [Ecological aspects and prophylaxis of Acinetobacter baumannii nosocomial infection].

    Science.gov (United States)

    Boukadida, J

    2000-01-01

    Acinetobacter Baumannii is an aerobic strit gram negative bacteria cause of epidemic infection in intensive care units this bacteria is isolated from the patient and its environment. The detection of AB infection require the isolation of patients and decontamination of the material despite the virulence of the germ, these measures are necessary due to the rapid extension of epidemic in the absence of adequate means.

  15. Caracterización de los plásmidos presentes en tres aislamientos multirresistentes de: Acinetobacter baumannii, Acinetobacter nosocomialis y Acinetobacter pittii obtenidos en hospitales colombianos.

    OpenAIRE

    Rodríguez Méndez, Tatiana

    2014-01-01

    En las últimas décadas, el control de las infecciones asociadas al cuidado de la salud causadas por bacterias del género Acinetobacter se ha convertido en un problema global, ya que un gran porcentaje de aislamientos hospitalarios presentan resistencia a la mayoría de antibióticos de uso común, incluyendo: Penicilinas, cefalosporinas, aminoglicósidos, quinolonas, tetraciclinas, cloranfenicol y carbapenémicos; existen gran cantidad de estudios a nivel mundial que relacionan la presencia de ele...

  16. Molecular characteristics of Multidrug Resistant Acinetobacter baumannii Isolates from US soldiers from Iraq at the National Naval Medical Center

    Science.gov (United States)

    Background: Infections with A. baumannii-calcoaceticus complex (ABC) have complicated the care of combat casualties, and the spread and global dissemination of imipenem resistant (IR) clones of ABC have been reported in recent years. However, the epidemiological features of the IR-ABCs in military t...

  17. Molecular analysis of imipenem-resistant Acinetobacter baumannii isolated from US service members wounded in Iraq, 2003–2008

    Science.gov (United States)

    Clonal spread and global dissemination of imipenem resistant (IR) A. baumannii-A. calcoaceticus complex (ABC) have been reported in recent years. However, the epidemiological features of the IR-ABCs in military treatment facilities (MTFs) have not been systematically studied. In this study, 298 ABC...

  18. Incidence of Acinetobacter species other than A. baumannii among clinical isolates of Acinetobacter: evidence for emerging species.

    Science.gov (United States)

    Turton, Jane F; Shah, Jayesh; Ozongwu, Chika; Pike, Rachel

    2010-04-01

    Six hundred ninety nonduplicate isolates of Acinetobacter species were identified using a combination of detection of bla(OXA-51-like) and rpoB sequence cluster analysis. Although most isolates were identified as A. baumannii (78%), significant numbers of other species, particularly A. lwoffii/genomic species 9 (8.8%), A. ursingii (4%), genomic species 3 (1.7%), and A. johnsonii (1.7%), were received, often associated with bacteremias.

  19. Acinetobacter Species Infections Among Navy and Marine Corps Beneficiaries: 2013 Annual Report

    Science.gov (United States)

    2014-11-19

    Health Level 7 (HL7) formatted microbiology data were used to identify Acinetobacter cases. These isolates were then matched to three databases... Microbiology records were matched to HL7 formatted pharmacy data to assess prescribing practices associated with Acinetobacter cases. Cases were also...matched to the Standard Inpatient Data Record (SIDR) database to determine exposure associations within the healthcare system. Microbiology records

  20. Genetic Environment and Transcription of ampC in an Acinetobacter baumannii Clinical Isolate

    OpenAIRE

    Segal, Heidi; Nelson, E.C.; Elisha, B. Gay

    2004-01-01

    An ampC gene was cloned from a clinical isolate of Acinetobacter baumannii (strain RAN). DNA sequencing and primer extension studies showed that ampC is transcribed from a promoter contained within a putative insertion sequence element which has been found to abut several different genes in Acinetobacter spp.

  1. Draft genome sequence of Acinetobacter pittii ST643 shared by cystic fibrosis patients

    Science.gov (United States)

    Rocha, Géssica A; Ferreira, Alex G; Lima, Danielle F; Leão, Robson S; Carvalho-Assef, Ana Paula D; Folescu, Tânia W; Albano, Rodolpho M; Marques, Elizabeth A

    2016-01-01

    Acinetobacter pittii has emerged as an important hospital pathogen that is associated with outbreaks and drug resistance. In cystic fibrosis (CF) patients, the detection of Acinetobacter spp. is rare; however, we isolated the A. pittii sequence type ST643 in several Brazilian CF patients treated in the same centre. The current study describes the draft genome of A. pittii ST643. PMID:27653362

  2. Acinetobacter sp. isolates from emergency departments in two hospitals of South Korea.

    Science.gov (United States)

    Choi, Ji-Young; Ko, Eun Ah; Kwon, Ki Tae; Lee, Shinwon; Kang, Choel In; Chung, Doo-Ryeon; Peck, Kyong Ran; Song, Jae-Hoon; Ko, Kwan Soo

    2014-10-01

    A total of 114 Acinetobacter sp. isolates were collected from patients in the emergency departments (EDs) of two Korean hospitals. Most isolates belonged to the Acinetobacter baumannii complex (105 isolates, 92.1 %). Imipenem resistance was found in 39 isolates (34.2 %) of the Acinetobacter sp. isolates, and 6 colistin-resistant isolates were also identified. Species distribution and antimicrobial-resistance rates were different between the two hospitals. In addition, two main clones were identified in the imipenem-resistant A. baumannii isolates from hospital B, but very diverse and novel genotypes were found in those from hospital A. Many Acinetobacter sp. isolates, including the imipenem-resistant A. baumannii, are considered to be associated with the community. The evidence of high antimicrobial resistance and different features in these Acinetobacter sp. isolates between the two EDs suggests the need for continuous testing to monitor changes in epidemiology.

  3. [Frequency and antimicrobial resistance of Acinetobacter species in a university hospital of Buenos Aires City].

    Science.gov (United States)

    Rodríguez, Carlos Hernán; Nastro, Marcela; Dabos, Laura; Vay, Carlos; Famiglietti, Angela

    2014-01-01

    Two-hundred Acinetobacter isolates belonging to 200 patients admitted to Hospital de Clínicas José de San Martín during the period March 2013-June 2014 were analyzed. The identification was performed by mass spectrometry and was confirmed by molecular methods. Susceptibility to antimicrobials was studied by the Vitek-2 system. A 94% correlation of both identification methods was found. Multidrug resistant Acinetobacter baumannii was the predominant genomic species (92.6%) in hospital-acquired infections, whereas Acinetobacter pitti and Acinetobacter nosocomialis accounted for 3.5% and 0.5% of the isolates recovered, respectively. In community-acquired infections a major predominance of the different genomic species was observed. Acinetobacter johnsonii and A. baumannii are the most frequent species, accounting for 45.9% of the isolates recovered. Resistance to carbapenems and minocycline was only observed in A. baumannii. Mass spectrophotometry was an effective tool for the identification of the different genomic species.

  4. [Current approaches to explain the virulence of Acinetobacter baumannii].

    Science.gov (United States)

    Aşık, Gülşah

    2011-04-01

    Acinetobacter baumannii which is one of the most frequent nosocomial pathogens, has drawn attention in the last years owing to multi-drug resistant strains. A.baumannii may give rise to nosocomial epidemics especially in intensive care units and may lead to treatment failure due to its increasing antimicrobial resistance. These gram-negative non-fermentative coccobacilli may be encountered also in community associated infections. However, they are frequently isolated in pneumonia, urinary tract infection, bacteremia, meningitis and wound infections that develop in patients hospitalized for serious diseases. Although detailed data about the epidemiology and antimicrobial resistance patterns related to this bacteria exist, relatively limited data is present about the virulence factors and environmental physiology of A.baumannii. The role of some bacterial virulence factors in the pathogenesis of Acinetobacter infections have been enlightened by recent investigations. Among these virulence factors, production of extracellular enzymes with lipolytic and cytolytic activities, outer membrane protein (AbOmpA) with apoptotic effects on epithelial cells, adhesion molecules (fimbria and AbOmpA) that function during attachment to epithelial cells, K1 type capsular structure, type-1 pili and AbOmpA induced biofilm formation, siderophore (acinetobactin) or hemin mediated iron acquisition mechanisms, quorum sensing system that functions by the help of N-acyl homoserine lacton signal molecules and cellular components that enable Acinetobacter species to live under inappropriate environmental conditions like dryness, low temperature, restricted nutritional elements, can be counted. New information about the virulence factors will help better understanding of the adaptive response of A.baumannii in the host setting. This review is focused on the current information about the virulence factors of of A.baumannii.

  5. Proliferation of spacecraft-associated Acinetobacter on alcohol solvents

    Science.gov (United States)

    Mogul, Rakesh; Cepeda, Ivonne; Brasali, Hania; Gornick, Trevor; Jain, Chirag; Kim, Eun Jin; Nguyen, Vinh Bao; Oei, Alex; Rodriguez, Joseph; Walker, Jillian; Savla, Gautam

    The Acinetobacter are the most abundant Gram-negative and non-spore forming bacteria found in the cleanroom facilities for Mars spacecraft. The spacecraft-associated Acinetobacter are extremotolerant towards hydrogen peroxide and have been shown to increase in abundance as a result of the spacecraft assembly process. To better understand the oligotrophic growth in the cleanroom environments, we have measured the growth of several Acinetobacter strains against ethanol and isopropanol, which are cleaning solvents used in the spacecraft assembly process. Our studies show that A. radioresistens 50v1, which was isolated from Mars Odyssey orbiter, optimally proliferates on 300 mM ethanol under minimal conditions at a growth rate that is 2-fold higher than that of the A. radioresistens type strain (strain 43998 (T) ). The impact of transition metals on the growth rates followed the trend of Fe (2+) > Mn (2+) > Zn (2+) , where Zn (2+) was inhibitory. In contrast, no growth on ethanol was observed for the novel species A. phoenicis 2P01AA, which was isolated from the facilities for the Mars Phoenix lander. Alcohol dehydrogenase activities measured in rich and minimal media paralleled these observations with the 50v1 strain possessing higher specific activities than the type strain, and the 2P01AA strain displaying no measurable activity in rich media. Preliminary studies indicate that isopropanol is insufficient as an energy source when in culture. The significance of these results as well as the observed differences between the Odyssey and Phoenix-associated strains will be discussed.

  6. Identification of Lama glama as Reservoirs for Acinetobacter lwoffii

    Science.gov (United States)

    Ledesma, Martín M.; Díaz, Ailén M.; Barberis, Claudia; Vay, Carlos; Manghi, Marcela A.; Leoni, Juliana; Castro, Marisa S.; Ferrari, Alejandro

    2017-01-01

    South American Camelids have an increasing relevance in local economies, worldwide. These animals are bred for their meat, fur and as companion and therapy animals. Thus, their sanitary status should be well-established. According to the OIE (World Organization for Animal Health), respiratory infections mainly produced by Pasteurella spp. have been reported for camelids. It has been stated that this microorganism causes a mild disease, although many authors report it is an important cause of mortality among alpacas. Nevertheless, the incidence of infection by Pasteurella spp. in camelids still needs to be investigated. The aim of the present study was to analyze the occurrence of nasopharyngeal colonization of Lama glama by respiratory bacteria, and to assess the usefulness of serological tests for clinical diagnosis. The colonization was studied by culture techniques carried out with material taken by nasopharyngeal swabs. Bacterial isolates were first phenotypically characterized and then identified by MALDI/TOF-MS. The presence of specific serum antibodies was studied by ELISA and Western blot. In the present work Pasteurella spp. was not found. Nevertheless, we report for the first time, the colonization of L. glama by bacteria of the Acinetobacter lwoffii, at a reliable level in 19.4% of the animals. Acinetobacter species are found in different environmental sources, as well as vegetables, animals, and humans, and their role in infections has recently gained relevance. The results presented herein contribute to a better understanding of the respiratory microbiota in camelids, and increase the knowledge about environmental distribution of Acinetobacter non-baumanii species. Given that these respiratory bacteria might be the cause of infection among cattle, and even humans, this report highlights the need for further research. PMID:28303121

  7. Two case reports of gastroendoscopy-associated Acinetobacter baumannii bacteremia.

    Science.gov (United States)

    Chen, Chang-Hua; Wu, Shun-Sheng; Huang, Chieh-Chen

    2013-05-14

    Two cases of gastroendoscopy-associated Acinetobacter baumannii (A. baumannii) bacteremia were discovered at the study hospital. The first case was a 66-year-old woman who underwent endoscopic retrograde cholangiopancreatography and endoscopic retrograde papillotomy, and then A. baumannii bacteremia occurred. The second case was a 70-year-old female who underwent endoscopic retrograde biliary drainage due to obstruction of intra-hepatic ducts, and bacteremia occurred due to polymicrobes (Escherichia coli, viridans streptococcus, and A. baumannii). After a literature review, we suggest that correct gastroendoscopy technique and skill in drainage procedures, as well as antibiotic prophylaxis, are of paramount importance in minimizing the risk of gastroendoscopy-associated bacteremia.

  8. Successful Eradication of Multidrug Resistant Acinetobacter in the Helsinki Burn Centre.

    Science.gov (United States)

    Lindford, Andrew; Kiuru, Valtteri; Anttila, Veli-Jukka; Vuola, Jyrki

    2015-01-01

    Multidrug-resistant (MDR) Acinetobacter is an important pathogen implicated in nosocomial infections in healthcare environments. Virulence factors, resistance mechanisms, and limited therapeutic options make this pathogen a major problem currently facing burn intensive care units (ICUs) worldwide. The purpose of this study was to assess the effect of infection control measures taken in Helsinki Burn Centre in 2001 on MDR Acinetobacter prevalence in ICU burn patients. Data were retrospectively collected from patient files from 1998 to 2012. ICU burn patients were defined as those with either over 30% of total body surface area burnt or requiring mechanical ventilation. Inclusion criteria consisted of patients who tested positive for Acinetobacter sp. in routine bacterial cultures or cultures taken because of a clinically suspected infection. Infection control interventions performed in 2001 consisted of various shower room renovations and changes in hospital hygiene and burn treatment regimes. Between 1998 and 2012, 75 patients were diagnosed with Acinetobacter sp. colonization. Following the infection control interventions the incidence of Acinetobacter sp. radically declined. Between 1998 and 2001, there were 31 cases of MDR Acinetobacter colonizations diagnosed, but from 2002 to 2012 no MDR strains were found. Changes to hospital hygiene and wound treatment protocols as well as structural changes to the hospital environment can have a major impact on preventing and treating Acinetobacter outbreaks in burn centers.

  9. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii.

    Science.gov (United States)

    Kröger, Carsten; Kary, Stefani C; Schauer, Kristina; Cameron, Andrew D S

    2016-12-28

    Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance.

  10. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens.

    Science.gov (United States)

    Tiwari, Vishvanath; Roy, Ranita; Tiwari, Monalisa

    2015-01-01

    Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem.

  11. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Carsten Kröger

    2016-12-01

    Full Text Available Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance.

  12. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens

    Directory of Open Access Journals (Sweden)

    Vishvanath eTiwari

    2015-06-01

    Full Text Available Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem.

  13. Acinetobacter baumannii in Localised Cutaneous Mycobacteriosis in Falcons

    Directory of Open Access Journals (Sweden)

    Margit Gabriele Muller

    2010-01-01

    Full Text Available Between May 2007 and April 2009, 29 falcons with identically localized, yellowish discolored cutaneous lesions in the thigh and lateral body wall region were presented at Abu Dhabi Falcon Hospital. Out of 18 falcons integrated in this study, 16 tested positive to Mycobacterium. avium complex. The 2 negative falcons tested positive in the Mycobacterium genus PCR. Moreover, 1 falcon tested positive to M. avium. paratuberculosis in tissue samples by PCR. In all cases, blood and fecal samples tested negative. In the acid-fast stain, all samples showed the for mycobacteriosis typical rods. Moreover, in 13 samples Acinetobacter baumannii was detected by PCR and proven by DNA sequencing. Clinical features included highly elevated WBCs, heterophilia, lymphocytopenia, monocytosis, severe anemia and weight loss. A. baumannii, a gram-negative bacillus with the ability to integrate foreign DNA, has emerged as one of the major multidrug resistant bacteria. In veterinary medicine, it has so far been detected in dogs, cats, horses and wild birds. To the authors' knowledge, this is the first report of an A. baumannii infection in falcons and of a veterinary Mycobacterium-Acinetobacter coinfection.

  14. Genetic Regulation of Virulence and Antibiotic Resistance in Acinetobacter baumannii

    Science.gov (United States)

    Kröger, Carsten; Kary, Stefani C.; Schauer, Kristina; Cameron, Andrew D. S.

    2016-01-01

    Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance. Here, we review current knowledge regarding the regulation of virulence genes and antibiotic resistance in Acinetobacter baumannii. A survey of the two-component systems AdeRS, BaeSR, GacSA and PmrAB explains how each contributes to antibiotic resistance and virulence gene expression, while BfmRS regulates cell envelope structures important for pathogen persistence. A. baumannii uses the transcription factors Fur and Zur to sense iron or zinc depletion and upregulate genes for metal scavenging as a critical survival tool in an animal host. Quorum sensing, nucleoid-associated proteins, and non-classical transcription factors such as AtfA and small regulatory RNAs are discussed in the context of virulence and antibiotic resistance. PMID:28036056

  15. Integrated Detection of Pathogens and Host Biomarkers for Wounds

    Science.gov (United States)

    2012-04-01

    EB471A Acinetobacter baumannii Acinetobacter SUN plasmid pRAY Stenotrophomonas sp. ET662B None None HP561A None None HP561B None None IS711A None...None Alloicoccus otidis None JR281A Acinetobacter baumannii / calcoaceticus complex None JR342A Acinetobacter baumanii Acinetobacter baumannii ...None None TN631B Enterococcus faecium None ZB191B Enterobacter cloacae Acinetobacter baumannii Enterobacter cloacae plasmid pEC01 These initial

  16. Antibiotic susceptibility of Acinetobacter species in intensive care unit in Montenegro.

    Science.gov (United States)

    Mijovic, Gordana; Pejakov, Ljubica; Vujosevic, Danijela

    2016-08-01

    The global increase in multidrug resistance of Acinetobacter has created widespread problems in the treatment of patients in intensive care units (ICUs). The aim of this study was to assess the current level of antimicrobial susceptibility of Acinetobacter species in ICU of Clinical Centre of Montenegro and determine their epidemiology. Antibiotic susceptibility was tested in 70 isolates of Acinetobacter collected from non-repeating samples taken from 40 patients. The first nine isolates were genotyped by repetitive sequence-based PCR (rep-PCR). Tigecycline was found to be the most active antimicrobial agent with 80.6% of susceptibility. All the isolates were multidrug resistant with fully resistance to cefalosporinas, piperacillin and piperacillin/tazobactam. More than half of them (58.5%) were probably extensively resistant. Seven out of nine examined strains were clonally related by rep-PCR. Our results showed extremely high rate of multidrug resistance (MDR) of Acinetobacter isolates and high percentage of its clonally spreading.

  17. Occurrence of High Catalase-containing Acinetobacter in Spacecraft Assembly Facilities

    Science.gov (United States)

    McCoy, K. B.; Derecho, I.; La Duc, M. T.; Vaishampayan, P.; Venkateswaran, K. J.; Mogul, R.

    2010-04-01

    In summary, the measurement of high catalase specific activity values for spacecraft-associated Acinetobacter strains is potentially the result of adaptation towards the harsh conditions of the clean rooms and assembly process.

  18. Study of Antimicrobial Resistance of Acinetobacter Strains Isolated From Blood Cultures

    Directory of Open Access Journals (Sweden)

    H Zandi

    2007-06-01

    Full Text Available Background: Acinetobacter spp are associated with various nosocomial infections like as septicemia and are isolated form blood cultures in hospitalized patients. Methods: In this study, 45 Acinetobacter strains were isolated from blood samples in Yazd shahid sadoughi hospital from 21 March 2005 to 20 September 2006 and were identified by biochemical tests. Antibiotic susceptibility of the strains was tested by standard disk diffusion method. Results: In this research, 45 isolates identified as Acinetobacter and of isolated strains, 88.8% of them found sensitive to imipenem and 80% to ciprofloxacin. Also 51.5% to nalidixic Acid 24.5% to trimethoprim/sulphametoxazole, 11.1% to ceftazidim and ceftriaxone, 8.8% to cefotaxime and cefexime and also 6.6% to ceftizoxime. Conclusion: Because of increasing of drug resistance in Acinetobacter spp. Isolated from blood samples, it is necessary to perform susceptibility testing, also imipenem and ciprofloxacin recommended for drug therapy.

  19. The first cases of human bacteremia caused by Acinetobacter seifertii in Japan.

    Science.gov (United States)

    Kishii, Kozue; Kikuchi, Ken; Tomida, Junko; Kawamura, Yoshiaki; Yoshida, Atsushi; Okuzumi, Katsuko; Moriya, Kyoji

    2016-05-01

    Acinetobacter seifertii, a novel species of Acinetobacter, was first reported in 2015. A. seifertii strains were isolated from human clinical specimens (blood, respiratory tract, and ulcer) and hospital environments. Here, we report the first cases of bacteremia caused by A. seifertii in patients with catheter-related bloodstream infection in Japan. The patients favorably recovered, without any complications, after removal of the peripheral intravenous catheters and administration of antibiotics. The pathogens were initially identified as Acinetobacter baumannii, using phenotypic methods and the MicroScan Walkaway System; however, rpoB gene sequence analysis indicated 99.54% similarity to A. seifertii. Moreover, antimicrobial susceptibility testing revealed that one of the strains was not susceptible to gentamicin and ceftazidime. Our report shows that Acinetobacter species other than A. baumannii can also cause nosocomial infections and that accurate methods for the identification of causative agents should be developed.

  20. Evaluation of the effect of appropriate antimicrobial therapy on mortality associated with Acinetobacter nosocomialis bacteraemia.

    Science.gov (United States)

    Kuo, Shu-Chen; Lee, Yi-Tzu; Yang, Su-Pen; Chiang, Mei-Chun; Lin, Yi-Tsung; Tseng, Fan-Chen; Chen, Te-Li; Fung, Chang-Phone

    2013-07-01

    Appropriate antimicrobial therapy is effective for severe infections caused by Acinetobacter baumannii, but efficacy for other Acinetobacter species remains to be established. The current study was designed to determine whether appropriate antimicrobial therapy reduces the mortality of patients with Acinetobacter nosocomialis bacteraemia. A 9-year retrospective study of 266 patients with monomicrobial A. nosocomialis bacteraemia was conducted at a large teaching hospital in Taiwan. Multivariable analysis was performed to evaluate the impact on 14-day mortality according to clinical characteristics, severity of disease and use of appropriate antimicrobial therapy. The influence of APACHE II score on the impact of appropriate antimicrobial therapy was analysed by including an interaction term. The overall 14-day mortality was 9.4%. Multivariable analysis revealed that APACHE II score was the only factor significantly associated with mortality (odds ratio, 1.18; 95% confidence interval, 1.11-1.25; p infections caused by two phenotypically undifferentiated Acinetobacter.

  1. Genome sequencing and annotation of Acinetobacter gerneri strain MTCC 9824T

    Directory of Open Access Journals (Sweden)

    Nitin Kumar Singh

    2014-12-01

    Full Text Available The genus Acinetobacter consists of 31 validly published species ubiquitously distributed in nature and primarily associated with nosocomial infection. We report the 4.4 Mb genome of Acinetobacter gerneri strain MTCC 9824T. The genome has a G + C content of 38.0% and includes 3 rRNA genes (5S, 23S16S and 64 aminoacyl-tRNA synthetase genes.

  2. Left-Sided Endocarditis Associated with Multi-Drug Resistance Acinetobacter Lwoffii

    Directory of Open Access Journals (Sweden)

    Naghmeh Moshtaghi

    2009-09-01

    Full Text Available Acinetobacter lwoffii, an important nosocomial pathogen, is a gram-negative aerobic bacillus that is a component of the normal flora on the skin, oropharynx, and perineum of about 20-25% of healthy individuals. We herein present a case of a 66-year-old man with combined mitral and aortic valve endocarditis associated with multi-drug resistance acinetobacter lowffii bacteremia.

  3. Draft Genome Sequences of Acinetobacter baumannii Isolates from Wounded Military Personnel.

    Science.gov (United States)

    Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

    2016-08-25

    Acinetobacter baumannii is a Gram-negative bacterium capable of causing hospital-acquired infections that has been grouped with Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as ESKAPE pathogens because of their extensive drug resistance phenotypes and increasing risk to human health. Twenty-four multidrug-resistant A. baumannii strains isolated from wounded military personnel were sequenced and annotated.

  4. Prognostic differences between VAP caused by Acinetobacter baumannii and VAP caused by other microorganisms

    OpenAIRE

    Di Bonito, Marianna; Caiazzo, Simona; Iannazzone, Marta; Miccichè, Viviana; De Marco, Giuseppe; De Robertis, Edoardo; Tufano, Rosalba; Piazza, Ornella

    2012-01-01

    Nosocomial infection, in particular pneumonia, is an important risk factor for hospital mortality and morbidity. Acinetobacter baumannii is a common multi-resistant microorganism responsible of Ventilator Associated Pneumonia (VAP). Currently Colistin is a rescue therapy for this pathogen. The purpose of this study is to compare the outcome of VAP caused by Acinetobacter baumannii and VAP by other microorganisms in critical patients. Comorbidity, prognostic scores, mortality and eradication f...

  5. Prognostic differences between VAP from Acinetobacter baumanii and VAP from other microorganisms

    OpenAIRE

    Di Bonito, Marianna; Caiazzo, Simona; Iannazzone, Marta; Miccichè, Viviana; De Marco, Giuseppe; De Robertis, Edoardo; Tufano, Rosalba; Piazza, Ornella

    2012-01-01

    Nosocomial infection, in particular pneumonia, is an important risk factor for hospital mortality and morbidity. Acinetobacter baumanii is a common multi-resistant microorganism responsible of Ventilator Associated Pneumonia (VAP). Currently Colistin is a rescue therapy for this pathogen. The purpose of this retrospective study is to compare the outcome of VAP caused by Acinetobacter baumanii and VAP from other microorganisms in critical patients. Comorbidity, prognostic scores, mortality and...

  6. Characterization and identification of newly isolated Acinetobacter baumannii strain serdang 1 for phenol removal

    Science.gov (United States)

    Yadzir, Z. H. M.; Shukor, M. Y.; Nazir, M. S.; Abdullah, M. A.

    2012-09-01

    A new indigenous bacterial strain from Malaysian soil contaminated with petroleum waste had been successfully isolated, characterized and identified for phenol removal. The gram negative bacteria showed 98% identity with Acinetobacter baumannii based on Biolog{trade mark, serif} Identification System and the determination of a partial 16S ribosomal RNA (rRNA) sequence. The isolate clustered with species belonging to Acinetobacter clade in a 16S rDNA-based neighbour-joining phylogenetic tree.

  7. Genome sequencing and annotation of Acinetobacter gyllenbergii strain MTCC 11365T

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    Nitin Kumar Singh

    2014-12-01

    Full Text Available The genus Acinetobacter consists of 31 validly published species ubiquitously distributed in nature and primarily associated with nosocomial infection. We report 4.3 Mb genome of the Acinetobacter gyllenbergii strain MTCC 11365T. The draft genome of A. gyllenbergii has a G + C content of 41.0% and includes 3 rRNA genes (5S, 23S, 16S and 67 aminoacyl-tRNA synthetase genes.

  8. Towards an explanation for the success of Acinetobacter baumannii in the human host

    OpenAIRE

    Breij, Anastasia (Anna)

    2012-01-01

    Acinetobacter baumannii is an important nosocomial pathogen responsible for outbreaks of infection worldwide. The studies presented in this thesis aimed to gain further insight into the bacterial and host factors associated with the pathogenesis of A. baumannii to seek an explanation for the clinical success of A. baumannii. We demonstrated that both A. baumannii and less virulent Acinetobacter species can adhere to surfaces and form a biofilm, albeit with a wide variation among strains of ea...

  9. Acinetobacter Baumannii in Intensive Care Units: prevention –nursing watch over

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    Mpitsiori Z

    2013-04-01

    Full Text Available Introduction: Acinetobacter Baumannii belongs to the large family of Acinetobacter, comes from the Greek word still, and for this reason it is called ‘Akinitovaktiridio’. Purpose: to review the recent literature on the genus Acinetobacter Baumannii in ICU and preventive measures against hospital infections. Methods: review from the Greek and foreign literature using keywords. Results: Acinetobacter ,during the last three decades , is of great interest in the medical community, because of the increasing infections in most hospital caused by this bacterium and the difficulties in its treatment: often severe with long hospitalization, antibiotic resistance , high treatment costs and mortality . There are reports concerning Acinetobacter epidemics in different hospitals, both in Greece and abroad. Epidemics of these patients in ICU may be linked, at least in part, to the increasingly invasive diagnostic and therapeutic techniques used in the ICU in the last two decades. The main infections it causes are: urinary tract and respiratory tract infections, bacteremia and meningitis are observed often amongst patients in the ICU. An important predisposing factor is previous antibiotic therapy. Conclusions: Carbapenems are considered the antibiotics of choice for the treatment of these infections. However, the past few years an increasing number of Carbapenems resistant Acinetobacter spp has been reported. The majority of Carbapenems resistant Acinetobacter spp involved in hospital infections belong to the species Acinetobacter Baumannii. In conclusion, the molecular epidemiology of strains is indispensable because it provides a useful reference at the dispersion of the hospital staff and rapid detection of new strains to take the necessary measures in time.

  10. Analysis of drug resistance in 1,861 strains of Acinetobacter baumannii

    OpenAIRE

    JIN, HAO; Qiu, Fan; JI, HONG JIAN; Lu, Qiang

    2016-01-01

    Acinetobacter baumannii is an emerging human pathogen that causes hospital-acquired infections. The trend in increased antimicrobial resistance limits the choice of effective antimicrobial agents. The present study reports the resistance to Acinetobacter baumannii and analyzes the associations between antibiotic use and resistance rates at a general hospital between 2010 and 2014. A total of 1,861 isolates were obtained from clinical cultures, accounting for 10.33% of all detected bacteria (1...

  11. Combined therapy for multi-drug-resistant Acinetobacter baumannii infection--is there evidence outside the laboratory?

    Science.gov (United States)

    Tuon, Felipe F; Rocha, Jaime L; Merlini, Alexandre B

    2015-09-01

    Acinetobacter are among the most common bacteria isolated in hospital infections, especially in developing countries. Multi-drug, extended-drug or pan-drug resistance makes treatment a real medical challenge. In the present review, the authors describe clinical and experimental data in order to present different current and potential future strategies to treat infections caused by multi-drug-resistant Acinetobacter. The therapeutic options for carbapenem-resistant Acinetobacter are scarce, and the current options have poor pharmacokinetic aspects and several side effects. Combined therapy has been an alternative for multi-drug-resistant Acinetobacter. However, this issue is always controversial. In some studies combined therapy has shown superiority for some strains of Acinetobacter in animal models and in vitro studies. However, studies with humans are scarce and too poor quality to suggest the best approach for the treatment of infections caused by multi-drug-resistant Acinetobacter baumannii.

  12. The role of Acinetobacter in the pathogenesis of multiple sclerosis examined by using Popper sequences.

    Science.gov (United States)

    Ebringer, Alan; Rashid, Taha; Wilson, Clyde

    2012-06-01

    Multiple sclerosis (MS) is an autoimmune neurological disorder. The role of 'Acinetobacter' has been examined using the method of Karl Popper and involves nine "Popper sequences". (1) The frequency of MS increases with latitudes in the Northern Hemisphere, and the reverse is found in the Southern Hemisphere. (2) Sinusitis is found frequently at colder latitudes. (3) Sinusitis occurs frequently in patients with MS. (4) Specific sequences of bovine myelin when injected into experimental animals will produce a neurological disorder resembling MS which is called "experimental allergic encephalomyelitis". (5) Computer analysis of myelin shows molecular mimicry with sequences found in Acinetobacter. (6) Antibodies to Acinetobacter bacteria are found in MS patients. (7) Acinetobacter bacteria are located on human skin and in the nasal sinuses. (8) IgA antibodies are preferentially elevated in the sera of MS patients, thereby suggesting the trigger microbe is acting across a mucosal surface probably located in the nasal sinuses. (9) Only Acinetobacter bacteria and no other microbes evoke statistically significant titres of antibodies in MS patients. These nine Popper sequences suggest that MS is most probably caused by infections with Acinetobacter bacteria in the nasal sinuses, and this could have therapeutic implications.

  13. Acinetobacter bohemicus sp. nov. widespread in natural soil and water ecosystems in the Czech Republic.

    Science.gov (United States)

    Krizova, Lenka; Maixnerova, Martina; Sedo, Ondrej; Nemec, Alexandr

    2014-10-01

    We investigated the taxonomic status of a phenetically unique group of 25 Acinetobacter strains which were isolated from multiple soil and water samples collected in natural ecosystems in the Czech Republic. Based on the comparative sequence analyses of the rpoB, gyrB, and 16S rRNA genes, the strains formed a coherent and well separated branch within the genus Acinetobacter. The genomic uniqueness of the group at the species level was supported by the low average nucleotide identity values (≤77.37%) between the whole genome sequences of strain ANC 3994(T) (NCBI accession no. APOH00000000) and the representatives of the known Acinetobacter species. Moreover, all 25 strains created a tight cluster clearly separated from all hitherto described species based on whole-cell protein profiling by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and shared a unique combination of metabolic and physiological properties. The capacity to assimilate l-histidine and the inability to grow at 35°C differentiated them from their phenotypically closest neighbor, Acinetobacter johnsonii. We conclude that the 25 strains represent a novel Acinetobacter species, for which the name Acinetobacter bohemicus sp. nov. is proposed. The type strain of A. bohemicus is ANC 3994(T) (=CIP 110496(T)=CCUG 63842(T)=CCM 8462(T)).

  14. Antimicrobial susceptibility of Acinetobacter clinical isolates and emerging antibiogram trends for nosocomial infection management

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    Muhammad Sohail

    2016-06-01

    Full Text Available Abstract: Introduction: The drug resistant Acinetobacter strains are important causes of nosocomial infections that are difficult to control and treat. This study aimed to determine the antimicrobial susceptibility patterns of Acinetobacter strains isolated from different clinical specimens obtained from patients belonging to different age groups. METHODS: In total, 716 non-duplicate Acinetobacter isolates were collected from the infected patients admitted to tertiary-care hospitals at Lahore, Pakistan, over a period of 28 months. The Acinetobacter isolates were identified using API 20E, and antimicrobial susceptibility testing was performed and interpreted according to Clinical and Laboratory Standards Institute (CLSI guidelines. RESULTS: The isolation rate of Acinetobacter was high from the respiratory specimens, followed by wound samples. Antibiotic susceptibility analyses of the isolates revealed that the resistance to cefotaxime and ceftazidime was the most common, in 710 (99.2% specimens each, followed by the resistance to gentamicin in 670 (93.6% isolates, and to imipenem in 651 (90.9% isolates. However, almost all isolates were susceptible to tigecycline, colistin, and polymyxin B. CONCLUSIONS: The present study showed the alarming trends of resistance of Acinetobacter strains isolated from clinical specimens to the various classes of antimicrobials. The improvement of microbiological techniques for earlier and more accurate identification of bacteria is necessary for the selection of appropriate treatments.

  15. Analysis of drug resistance in 1,861 strains of Acinetobacter baumannii

    Science.gov (United States)

    JIN, HAO; QIU, FAN; JI, HONG JIAN; LU, QIANG

    2016-01-01

    Acinetobacter baumannii is an emerging human pathogen that causes hospital-acquired infections. The trend in increased antimicrobial resistance limits the choice of effective antimicrobial agents. The present study reports the resistance to Acinetobacter baumannii and analyzes the associations between antibiotic use and resistance rates at a general hospital between 2010 and 2014. A total of 1,861 isolates were obtained from clinical cultures, accounting for 10.33% of all detected bacteria (1,861/18,016). The strains were mainly from respiratory samples (1,628 isolates, 87.5%) and the intensive care unit (696 isolates, 37.4%). The resistance rates of Acinetobacter baumannii to the majority of antibiotics were >50%, particularly the resistance rate to cefoperazone/sulbactam increased from 47.37 in 2011 to 89.25% in 2014. However, the rates of imipenem and cilastatin sodium decreased from 81.03 to 69.44% due to the antibiotic policy. There were Pearson significant associations between the use of three antibiotics and resistance in Acinetobacter baumannii to this drug, piperacillin/tazobactam (r=0.976, P<0.01), gentamicin (r=0.870, P<0.01) and cefoxitin (r=0.741, P<0.05). Therefore, a combination of drugs should be adopted to treat Acinetobacter baumannii infections. Microbiology laboratory support and surveillance policies are essential to control the emergence of multidrug-resistance Acinetobacter baumannii. PMID:27073633

  16. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii.

    Science.gov (United States)

    Merabishvili, Maia; Vandenheuvel, Dieter; Kropinski, Andrew M; Mast, Jan; De Vos, Daniel; Verbeken, Gilbert; Noben, Jean-Paul; Lavigne, Rob; Vaneechoutte, Mario; Pirnay, Jean-Paul

    2014-01-01

    Based on genotyping and host range, two newly isolated lytic bacteriophages, myovirus vB_AbaM_Acibel004 and podovirus vB_AbaP_Acibel007, active against Acinetobacter baumannii clinical strains, were selected from a new phage library for further characterization. The complete genomes of the two phages were analyzed. Both phages are characterized by broad host range and essential features of potential therapeutic phages, such as short latent period (27 and 21 min, respectively), high burst size (125 and 145, respectively), stability of activity in liquid culture and low frequency of occurrence of phage-resistant mutant bacterial cells. Genomic analysis showed that while Acibel004 represents a novel bacteriophage with resemblance to some unclassified Pseudomonas aeruginosa phages, Acibel007 belongs to the well-characterized genus of the Phikmvlikevirus. The newly isolated phages can serve as potential candidates for phage cocktails to control A. baumannii infections.

  17. Stress responses in the opportunistic pathogen Acinetobacter baumannii.

    Science.gov (United States)

    Fiester, Steven E; Actis, Luis A

    2013-03-01

    Acinetobacter baumannii causes a wide range of severe infections among compromised and injured patients worldwide. The relevance of these infections are, in part, due to the ability of this pathogen to sense and react to environmental and host stress signals, allowing it to persist and disseminate in medical settings and the human host. This review summarizes current knowledge on the roles that environmental and cellular stressors play in the ability of A. baumannii to resist nutrient deprivation, oxidative and nitrosative injury, and even the presence of the commonly used antiseptic ethanol, which could serve as a nutrient- and virulence-enhancing signal rather than just being a convenient disinfectant. Emerging experimental evidence supports the role of some of these responses in the pathogenesis of the infections A. baumannii causes in humans and its capacity to resist antibiotics and host response effectors.

  18. Optimum treatment strategies for carbapenem-resistant Acinetobacter baumannii bacteremia.

    Science.gov (United States)

    Garnacho-Montero, José; Amaya-Villar, Rosario; Ferrándiz-Millón, Carmen; Díaz-Martín, Ana; López-Sánchez, José María; Gutiérrez-Pizarraya, Antonio

    2015-06-01

    Carbapenem-resistant Acinetobacter baumannii (CRAB) constitutes an increasing problem worldwide. CRAB bacteremia is associated with a high fatality rate and its optimal treatment has not been established. Early institution of appropriate therapy is shown to improve survival of patients with CRAB bloodstream infection. Regrettably, treatment options are limited. Little information exists about the efficacy of sulbactam for the treatment of CRAB bacteremia. Colistin and tigecycline possess good in vitro activity and represent in many cases the only therapeutic options although clinical data are scarce. The need for a loading dose of colistin has been recently demonstrated to rapidly achieve therapeutic levels. The use of combination therapy is also a matter of debate but current evidence do not support its routine use.

  19. Community-acquired Acinetobacter baumannii: clinical characteristics, epidemiology and pathogenesis.

    Science.gov (United States)

    Dexter, Carina; Murray, Gerald L; Paulsen, Ian T; Peleg, Anton Y

    2015-05-01

    Community-acquired Acinetobacter baumannii (CA-Ab) is a rare but serious cause of community-acquired pneumonia in tropical regions of the world. CA-Ab infections predominantly affect individuals with risk factors, which include excess alcohol consumption, diabetes mellitus, smoking and chronic lung disease. CA-Ab pneumonia presents as a surprisingly fulminant course and is characterized by a rapid onset of fever, severe respiratory symptoms and multi-organ dysfunction, with a mortality rate reported as high as 64%. It is unclear whether the distinct clinical syndrome caused by CA-Ab is because of host predisposing factors or unique bacterial characteristics, or a combination of both. Deepening our understanding of the drivers of overwhelming CA-Ab infection will provide important insights into preventative and therapeutic strategies.

  20. OXA-type carbapenemases in Acinetobacter baumannii in South America.

    Science.gov (United States)

    Opazo, Andrés; Domínguez, Mariana; Bello, Helia; Amyes, Sebastian G B; González-Rocha, Gerardo

    2012-04-13

    Acinetobacter baumannii is an opportunistic pathogen that is frequently involved in outbreaks of infection, occurring mostly in intensive care units. The increasing incidence of carbapenem resistance in A. baumannii worldwide is a concern since it limits drastically the range of therapeutic alternatives. The most important mechanism of carbapenem resistance is the enzymatic hydrolysis mediated by carbapenemases. In A. baumannii these enzymes are usually OXA-type carbapenemases, and belong to class D according to the classification of Ambler. The OXA-type carbapenemases are divided into five subgroups, four of which correspond to acquired carbapenemases, which accounts for the distribution of genes blaOXA in different geographic areas. In this work we review the different types of OXA-type carbapenemases present in A. baumannii, emphasizing the current situation in South America with special mention to the findings in Chile.

  1. Current molecular methods in epidemiological typing of Acinetobacter baumannii.

    Science.gov (United States)

    Rafei, Rayane; Kempf, Marie; Eveillard, Matthieu; Dabboussi, Fouad; Hamze, Monzer; Joly-Guillou, Marie-Laure

    2014-01-01

    The emergence of Acinetobacter baumannii during recent decades as an important nosocomial pathogen responsible of worldwide, intensively documented, outbreaks has resulted in a need for effective epidemiological typing methods. Throughout the years, many typing methods for A. baumannii epidemiological studies have been proposed from phenotypic to molecular methods. Currently, the use of phenotypic typing methods have declined considerably and been progressively replaced by molecular methods. In this review, we introduce the current molecular methods available for A. baumannii typing. Each method has its own advantages and disadvantages, and the selection of an appropriate genotyping method depends on studied objectives. This review sheds light on questions in different epidemiological settings and most molecular methods used to fit these objectives.

  2. The structure of alanine racemase from Acinetobacter baumannii.

    Science.gov (United States)

    Davis, Emily; Scaletti-Hutchinson, Emma; Opel-Reading, Helen; Nakatani, Yoshio; Krause, Kurt L

    2014-09-01

    Acinetobacter baumannii is an opportunistic Gram-negative bacterium which is a common cause of hospital-acquired infections. Numerous antibiotic-resistant strains exist, emphasizing the need for the development of new antimicrobials. Alanine racemase (Alr) is a pyridoxal 5'-phosphate dependent enzyme that is responsible for racemization between enantiomers of alanine. As D-alanine is an essential component of the bacterial cell wall, its inhibition is lethal to prokaryotes, making it an excellent antibiotic drug target. The crystal structure of A. baumannii alanine racemase (AlrAba) from the highly antibiotic-resistant NCTC13302 strain has been solved to 1.9 Å resolution. Comparison of AlrAba with alanine racemases from closely related bacteria demonstrates a conserved overall fold. The substrate entryway and active site of the enzymes were shown to be highly conserved. The structure of AlrAba will provide the template required for future structure-based drug-design studies.

  3. In vitro activity of ceftobiprole against Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Marti, Sara; Sánchez-Céspedes, Javier; Espinal, Paula; Vila, Jordi

    2009-09-01

    Acinetobacter baumannii is a multiresistant opportunistic nosocomial pathogen responsible for outbreaks worldwide. The main infection caused by this microorganism is nosocomial pneumonia, in particular ventilator-associated pneumonia in patients in Intensive Care Units. Treatment of these nosocomial infections is becoming problematic because the level of resistance to antimicrobial agents is rising. Ceftobiprole is a new cephalosporin with activity against Gram-positive and Gram-negative pathogens. This study evaluated the in vitro activity of ceftobiprole against a collection of 58 A. baumannii clinical isolates and showed that the activity of ceftobiprole was superior to ceftazidime and cefepime when the bla(ADC)-like gene was not expressed or was expressed at a low level.

  4. Characterization of newly isolated lytic bacteriophages active against Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Maia Merabishvili

    Full Text Available Based on genotyping and host range, two newly isolated lytic bacteriophages, myovirus vB_AbaM_Acibel004 and podovirus vB_AbaP_Acibel007, active against Acinetobacter baumannii clinical strains, were selected from a new phage library for further characterization. The complete genomes of the two phages were analyzed. Both phages are characterized by broad host range and essential features of potential therapeutic phages, such as short latent period (27 and 21 min, respectively, high burst size (125 and 145, respectively, stability of activity in liquid culture and low frequency of occurrence of phage-resistant mutant bacterial cells. Genomic analysis showed that while Acibel004 represents a novel bacteriophage with resemblance to some unclassified Pseudomonas aeruginosa phages, Acibel007 belongs to the well-characterized genus of the Phikmvlikevirus. The newly isolated phages can serve as potential candidates for phage cocktails to control A. baumannii infections.

  5. Comparative analysis of Acinetobacters: three genomes for three lifestyles.

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    David Vallenet

    Full Text Available Acinetobacter baumannii is the source of numerous nosocomial infections in humans and therefore deserves close attention as multidrug or even pandrug resistant strains are increasingly being identified worldwide. Here we report the comparison of two newly sequenced genomes of A. baumannii. The human isolate A. baumannii AYE is multidrug resistant whereas strain SDF, which was isolated from body lice, is antibiotic susceptible. As reference for comparison in this analysis, the genome of the soil-living bacterium A. baylyi strain ADP1 was used. The most interesting dissimilarities we observed were that i whereas strain AYE and A. baylyi genomes harbored very few Insertion Sequence elements which could promote expression of downstream genes, strain SDF sequence contains several hundred of them that have played a crucial role in its genome reduction (gene disruptions and simple DNA loss; ii strain SDF has low catabolic capacities compared to strain AYE. Interestingly, the latter has even higher catabolic capacities than A. baylyi which has already been reported as a very nutritionally versatile organism. This metabolic performance could explain the persistence of A. baumannii nosocomial strains in environments where nutrients are scarce; iii several processes known to play a key role during host infection (biofilm formation, iron uptake, quorum sensing, virulence factors were either different or absent, the best example of which is iron uptake. Indeed, strain AYE and A. baylyi use siderophore-based systems to scavenge iron from the environment whereas strain SDF uses an alternate system similar to the Haem Acquisition System (HAS. Taken together, all these observations suggest that the genome contents of the 3 Acinetobacters compared are partly shaped by life in distinct ecological niches: human (and more largely hospital environment, louse, soil.

  6. Bacteremic nosocomial pneumonia caused by Acinetobacter baumannii and Acinetobacter nosocomialis: a single or two distinct clinical entities?

    Science.gov (United States)

    Lee, Y-T; Kuo, S-C; Yang, S-P; Lin, Y-T; Chiang, D-H; Tseng, F-C; Chen, T-L; Fung, C-P

    2013-07-01

    The phenotypically indistinguishable Acinetobacter baumannii and Acinetobacter nosocomialis have become leading pathogens causing nosocomial pneumonia in critically ill patients. A. baumannii and A. nosocomialis nosocomial pneumonias were grouped as a single clinical entity previously. This study aimed to determine whether they are the same or a different clinical entity. A total of 121 patients with A. baumannii and 131 with A. nosocomialis bacteremic nosocomial pneumonia were included during an 8-year period. Despite the similar Charlson co-morbidity scores at admission, patients with A. baumannii pneumonia were more likely to have abnormal haematological findings, lobar pneumonia, significantly higher Acute Physiology and Chronic Health Evaluation II scores and higher frequency of shock at the onset of bacteraemia than those with A. nosocomialis pneumoni. A. baumannii isolates were resistant to more classes of antimicrobials, except colistin, and therefore the patients with A. baumannii pneumonia were more likely to receive inappropriate antimicrobial therapy. The 14-day mortality was significantly higher in patients with A. baumannii pneumonia (34.7% vs. 15.3%, p 0.001). A. baumannii was an independent risk factor for mortality (OR, 2.03; 95% CI, 1.05-3.90; p 0.035) in the overall cohort after adjustment for other risk factors for death, including inappropriate antimicrobial therapy. The results demonstrated the difference in clinical presentation, microbial characteristics and outcomes between A. baumannii and A. nosocomialis nosocomial pneumonia, and supported that they are two distinct clinical entities.

  7. The Antibacterial Activity Evaluation of the Nanoparticles of Silver on Acinetobacter Baumannii

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    Seyedeh Nasim Karimipour

    2016-09-01

    Full Text Available Background & Objective: Due to the high drug resistance in Acinetobacter baumannii, in this research, antibacterial properties of nano silver was evaluated for Acinetobacter baumannii. Materials & Methods: The nano silver with approximate diameter of 20 nanometer from Pishtazan Inc. Mashad, Iran and 5 nanometer from the Department of Chemistry in Maragheh University were prepared. Its concentration was determined by spectroscopy method in Tabriz Chemistry University.  Antimicrobial effects were determined by Mean Inhibitory Concentration (MIC and Minimal Bacterial Concentration (MBC by micro-broth-dilution method, disc diffusion and well diffusion methods. Anti-bacterial activity of nano-silver was tested for Acinetobacter baumannii NCTC12516 on 20 clinical strains (collected from Imam Reza Hospital in Tabriz. Results: The results showed the MIC and MBC of 20nm nanoparticles were 1250 ppm and 2500 ppm, respectively. On the other hand, the MIC and MBC of 5 nm nanoparticles were 156 ppm and 312 ppm, respectively. According to these findings, the MIC and MBC identified for clinical Acinetobacter baumannii strains under study along with the NCTC12516 strain did not show a significant difference. Yet the amount of inhibition for the 20nm nanoparticles in the density of 20000 ppm of clinical Acinetobacter baumannii and NCTC12516 strains was 11 millimeter with the disc diffusion method and 9.5 millimeter for the well diffusion method with the same concentration. The amount of inhibition of 5nm nanoparticles in the 250-ppm concentration with both disc diffusion and well diffusion methods was 9.5 millimeter. Conclusions: Acinetobacter baumannii is susceptible to nano-silver. Also the same MIC and MBC in multiple clinical strains suggests that there is not resistance to silver nanoparticles in Acinetobacter baumannii

  8. Characterization of plasmids in extensively drug-resistant acinetobacter strains isolated in India and Pakistan.

    Science.gov (United States)

    Jones, Lim S; Carvalho, Maria J; Toleman, Mark A; White, P Lewis; Connor, Thomas R; Mushtaq, Ammara; Weeks, Janis L; Kumarasamy, Karthikeyan K; Raven, Katherine E; Török, M Estée; Peacock, Sharon J; Howe, Robin A; Walsh, Timothy R

    2015-02-01

    The blaNDM-1 gene is associated with extensive drug resistance in Gram-negative bacteria. This probably spread to Enterobacteriaceae from Acinetobacter spp., and we characterized plasmids associated with blaNDM-1 in Acinetobacter spp. to gain insight into their role in this dissemination. Four clinical NDM-1-producing Acinetobacter species strains from India and Pakistan were investigated. A plasmid harboring blaNDM-1, pNDM-40-1, was characterized by whole-genome sequencing of Acinetobacter bereziniae CHI-40-1 and comparison with related plasmids. The presence of similar plasmids in strains from Pakistan was sought by PCR and sequencing of amplicons. Conjugation frequency was tested and stability of pNDM-40-1 investigated by real-time PCR of isolates passaged with and without antimicrobial selection pressure. A. bereziniae and Acinetobacter haemolyticus strains contained plasmids similar to the pNDM-BJ01-like plasmids identified in Acinetobacter spp. in China. The backbone of pNDM-40-1 was almost identical to that of pNDM-BJ01-like plasmids, but the transposon harboring blaNDM-1, Tn125, contained two short deletions. Escherichia coli and Acinetobacter pittii transconjugants were readily obtained. Transconjugants retained pNDM-40-1 after a 14-day passage experiment, although stability was greater with meropenem selection. Fragments of pNDM-BJ01-like plasmid backbones are found near blaNDM-1 in some genetic contexts from Enterobacteriaceae, suggesting that cross-genus transfer has occurred. pNDM-BJ01-like plasmids have been described in isolates originating from a wide geographical region in southern Asia. In vitro data on plasmid transfer and stability suggest that these plasmids could have contributed to the spread of blaNDM-1 into Enterobacteriaceae.

  9. Multidrug resistant Acinetobacter baumannii: a descriptive study in a city hospital

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    Pratap Siddharth

    2010-07-01

    Full Text Available Abstract Background Multidrug resistant Acinetobacter baumannii, (MRAB is an important cause of hospital acquired infection. The purpose of this study is to determine the risk factors for MRAB in a city hospital patient population. Methods This study is a retrospective review of a city hospital epidemiology data base and includes 247 isolates of Acinetobacter baumannii (AB from 164 patients. Multidrug resistant Acinetobacter baumannii was defined as resistance to more than three classes of antibiotics. Using the non-MRAB isolates as the control group, the risk factors for the acquisition of MRAB were determined. Results Of the 247 AB isolates 72% (177 were multidrug resistant. Fifty-eight percent (143/247 of isolates were highly resistant (resistant to imipenem, amikacin, and ampicillin-sulbactam. Of the 37 patients who died with Acinetobacter colonization/infection, 32 (86% patients had the organism recovered from the respiratory tract. The factors which were found to be significantly associated (p ≤ 0.05 with multidrug resistance include the recovery of AB from multiple sites, mechanical ventilation, previous antibiotic exposure, and the presence of neurologic impairment. Multidrug resistant Acinetobacter was associated with significant mortality when compared with sensitive strains (p ≤ 0.01. When surgical patients (N = 75 were considered separately, mechanical ventilation and multiple isolates remained the factors significantly associated with the development of multidrug resistant Acinetobacter. Among surgical patients 46/75 (61% grew a multidrug resistant strain of AB and 37/75 (40% were resistant to all commonly used antibiotics including aminoglycosides, cephalosporins, carbepenems, extended spectrum penicillins, and quinolones. Thirty-five percent of the surgical patients had AB cultured from multiple sites and 57% of the Acinetobacter isolates were associated with a co-infecting organism, usually a Staphylococcus or Pseudomonas. As

  10. A selective medium for the isolation of the acinetobacter genus bacteria Um Meio Seletivo para o Isolamento de Bactérias do Gênero Acinetobacter

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    Altair A. Zebral

    1980-12-01

    Full Text Available A selective and differencial medium was developed for the isolation of Acinetobacter genus bacteria. This Acinobacter Agar Medium (p.H + 7.4 contains in grams per litre: thiotone, 10; yeast extract, 3; naC1, 5; saccharose, 10; mannitol, 10; sodium citrate, 0.5; sodium desoxycholate, 0.1; crystal violet, 0.00025; phenol red, 0.04 and agar-agar 15. This medium has the advantage of inhibiting the growth of cocci and Gram-positive bacilli, by the use of sodium citrate and sodium desoxycholate associated with the crystal violet; and of differentiating the Gram-negative bacilli from the Enterobacteriaceae, through the fermentative activity upon the saccharose and/or mannitol, contrasting with the complete inactivity of the Acinetobacter genus bacteria over those substances.Um meio seletivo e diferenciador foi desenvolvido para facilitar o isolamento das bactérias do gênero Acinetobacter. Este meio (Agar Acinetobacter contém em gramas por litro: Tiotone (BBL, 10; extrato de levedura (BBL, 3; NaC1, 5; sacarose, 10; manitol, 10; citrato de sódio, 0,5; desoxicolato de sódio, 0,1; cristal violeta, 0,00025; vermelho de fenol, 0,04 e pH 7,4. Apresenta a vantagem de impedir o crescimento dos cocos e bacilos Gram positivos, pelo emprego do citrato de sódio e do desoxicolato de sódio, associados ao cristal violeta e de diferenciar os bacilos Gram negativos da família Enterobacteriaceae, pela sua atividade fermentativa sobre a sacarose e/ou manitol, em contraste com a completa inatividade das bactérias do gênero Acinetobacter sobre os mesmos substratos.

  11. Outbreak of multidrug-resistant Acinetobacter baumannii in an intensive care unit.

    Science.gov (United States)

    Dettori, Marco; Piana, Andrea; Deriu, Maria Grazia; Lo Curto, Paola; Cossu, Andrea; Musumeci, Rosario; Cocuzza, Clementina; Astone, Vito; Contu, Maria Antonietta; Sotgiu, Giovanni

    2014-04-01

    Acinetobacter baumannii is a ubiquitous microrganism often able to colonize and survive in different environments. Currently it is one of the most common pathogens responsible for nosocomial infections, including outbreaks, especially in long-term care facilities. The aim of this study was to show the results of an environmental investigation and genotyping analysis of multidrug-resistant Acinetobacter baumannii associated with an outbreak in an intensive care unit of a tertiary hospital located in Northern Sardinia, Italy. Positive cultures of MDR Acinetobacter baumannii were reported during the month of June 2012, after the collection of biological samples from ten patients. Acinetobacter baumannii was isolated during the following environmental investigation from the headboard of two beds. All the strains were genotyped by performing multiplex PCR to identify the presence of genes encoding carbapenemases. The results showed specific bands of bla(OXA-51-like) gene and of the bla(OXA-23-like) gene. PFGE highlighted minimal differences in genomic fingerprints, while the cluster analysis grouped the isolated microorganisms into two closely related clusters, characterized by Dice's similarity coefficient equal to 95.1%. MLST showed that the strains belonged to ST31. The results of the study highlight the need, especially in high-risk areas, to adopt strict hygiene practices, particularly hand hygiene, and to ensure an appropriate turnover of personal protective equipment, which could be responsible for the spread of biological agents, such as MDR Acinetobacter baumannii.

  12. Description of Acinetobacter populi sp. nov. isolated from symptomatic bark of Populus x euramericana canker.

    Science.gov (United States)

    Li, Yong; Chang, Jupu; Guo, Li-min; Wang, Hai-Ming; Xie, Shou-jiang; Piao, Chun-gen; He, Wei

    2015-12-01

    Five Gram-negative, non-motile, rod-shaped bacterial strains were isolated from cankers of Populus x euramericana collected from different locations in Puyang city, Henan Province, China. The five strains were characterized by nutritional and physiological testing and DNA sequence analysis. Haemolysis was not observed on agar media supplemented with sheep erythrocytes. The strains could be distinguished from members of most species of the genus Acinetobacter by their inability to assimilate L-arginine and benzoate. The five strains formed a single branch in phylogenetic trees based on 16S rRNA, gyrB and rpoB individual gene sequence analysis,indicating that they all belonged to a single taxon within the genus Acinetobacter. DNA-DNA hybridization results indicated that the five isolates represented to a single species that was separate from Acinetobacter puyangensis. On the basis of the phenotypic, genotypic and phylogenetic characteristics, the five strains are considered to represent a novel species of the genus Acinetobacter, for which the name Acinetobacter populi sp. nov. is proposed. The typestrain of A. populi sp. nov. is PBJ7T (CFCC 11170T=KCTC 42272T).

  13. Extremotolerant survival and proteomics of Acinetobacter isolated from spacecraft assembly facilities

    Science.gov (United States)

    Mogul, Rakesh; Vaishampayan, Parag; Venkateswaran, Kasthuri; McCoy, Kelly; Derecho, Ivy; Dallal, Freida

    2012-07-01

    Herein, we report on the extreme hydrogen peroxide resistance of Acinetobacter isolated from the assembly facilities for the Mars Odyssey orbiter and Phoenix lander. Specific activity experiments on 10 different spacecraft-associated Acinetobacter strains show that the catalase contents are 15-250-fold greater than that of E. coli. Among this group, the highest and lowest catalase-containing strains, which were Acinetobacter nov. sp. 2P01AA and Acinetobacter radioresistens 50v1, demonstrated no significant and 2-log reductions in survivability upon exposure to 100 mM hydrogen peroxide (1 hr), respectively. These survivals are among the highest reported for non-spore forming Gram-negative bacteria. Comparative proteomics on these strains reveals that alkyl hydroperoxide reductase, ATP synthase, dihydrolipoamide dehydrogenase, and peptidyl-tRNA hydrolase also contribute to the hydrogen peroxide extremotolerance. Together, the survival and metabolic features of the spacecraft-associated Acinetobacter indicate that survival in the dry and low-nutrient environments of clean rooms is supported by factors such as oxidant degradation, energy management, and protein biosynthesis.

  14. Characterisation and genome sequence of the lytic Acinetobacter baumannii bacteriophage vB_AbaS_Loki

    Science.gov (United States)

    Wand, Matthew E.; Briers, Yves; Lavigne, Rob; Sutton, J. Mark; Reynolds, Darren M.

    2017-01-01

    Acinetobacter baumannii has emerged as an important nosocomial pathogen in healthcare and community settings. While over 100 of Acinetobacter phages have been described in the literature, relatively few have been sequenced. This work describes the characterisation and genome annotation of a new lytic Acinetobacter siphovirus, vB_AbaS_Loki, isolated from activated sewage sludge. Sequencing revealed that Loki encapsulates a 41,308 bp genome, encoding 51 predicted open reading frames. Loki is most closely related to Acinetobacter phage IME_AB3 and more distantly related to Burkholderia phage KL1, Paracoccus phage vB_PmaS_IMEP1 and Pseudomonas phages vB_Pae_Kakheti25, vB_PaeS_SCH_Ab26 and PA73. Loki is characterised by a narrow host range, among the 40 Acinetobacter isolates tested, productive infection was only observed for the propagating host, A. baumannii ATCC 17978. Plaque formation was found to be dependent upon the presence of Ca2+ ions and adsorption to host cells was abolished upon incubation with a mutant of ATCC 17978 encoding a premature stop codon in lpxA. The complete genome sequence of vB_AbaS_Loki was deposited in the European Nucleotide Archive (ENA) under the accession number LN890663. PMID:28207864

  15. Characterisation and genome sequence of the lytic Acinetobacter baumannii bacteriophage vB_AbaS_Loki.

    Science.gov (United States)

    Turner, Dann; Wand, Matthew E; Briers, Yves; Lavigne, Rob; Sutton, J Mark; Reynolds, Darren M

    2017-01-01

    Acinetobacter baumannii has emerged as an important nosocomial pathogen in healthcare and community settings. While over 100 of Acinetobacter phages have been described in the literature, relatively few have been sequenced. This work describes the characterisation and genome annotation of a new lytic Acinetobacter siphovirus, vB_AbaS_Loki, isolated from activated sewage sludge. Sequencing revealed that Loki encapsulates a 41,308 bp genome, encoding 51 predicted open reading frames. Loki is most closely related to Acinetobacter phage IME_AB3 and more distantly related to Burkholderia phage KL1, Paracoccus phage vB_PmaS_IMEP1 and Pseudomonas phages vB_Pae_Kakheti25, vB_PaeS_SCH_Ab26 and PA73. Loki is characterised by a narrow host range, among the 40 Acinetobacter isolates tested, productive infection was only observed for the propagating host, A. baumannii ATCC 17978. Plaque formation was found to be dependent upon the presence of Ca2+ ions and adsorption to host cells was abolished upon incubation with a mutant of ATCC 17978 encoding a premature stop codon in lpxA. The complete genome sequence of vB_AbaS_Loki was deposited in the European Nucleotide Archive (ENA) under the accession number LN890663.

  16. A new subclass of intrinsic aminoglycoside nucleotidyltransferases, ANT(3")-II, is horizontally transferred among Acinetobacter spp. by homologous recombination

    Science.gov (United States)

    Zhang, Gang; Leclercq, Sébastien Olivier; Tian, Jingjing; Wang, Chao; Ai, Guomin; Liu, Shuangjiang

    2017-01-01

    The emergence and spread of antibiotic resistance among Acinetobacter spp. have been investigated extensively. Most studies focused on the multiple antibiotic resistance genes located on plasmids or genomic resistance islands. On the other hand, the mechanisms controlling intrinsic resistance are still not well understood. In this study, we identified the novel subclass of aminoglycoside nucleotidyltransferase ANT(3")-II in Acinetobacter spp., which comprised numerous variants distributed among three main clades. All members of this subclass can inactivate streptomycin and spectinomycin. The three ant(3")-II genes, encoding for the three ANT(3")-II clades, are widely distributed in the genus Acinetobacter and always located in the same conserved genomic region. According to their prevalence, these genes are intrinsic in Acinetobacter baumannii, Acinetobacter pittii, and Acinetobacter gyllenbergii. We also demonstrated that the ant(3")-II genes are located in a homologous recombination hotspot and were recurrently transferred among Acinetobacter species. In conclusion, our findings demonstrated a novel mechanism of natural resistance in Acinetobacter spp., identified a novel subclass of aminoglycoside nucleotidyltransferase and provided new insight into the evolutionary history of intrinsic resistance genes. PMID:28152054

  17. Bloodstream infection caused by Acinetobacter junii in a patient with acute lymphoblastic leukaemia after allogenic haematopoietic cell transplantation.

    Science.gov (United States)

    Cayô, Rodrigo; Yañez San Segundo, Lucrecia; Pérez del Molino Bernal, Inmaculada Concepción; García de la Fuente, Celia; Bermúdez Rodríguez, Maria Aranzazu; Calvo, Jorge; Martínez-Martínez, Luis

    2011-03-01

    Acinetobacter junii is a rare human pathogen associated with bacteraemia in neonates and paediatric oncology patients. We present a case of A. junii causing bacteraemia in an adult transplant patient with leukaemia. The correct identification of Acinetobacter species can highlight the clinical significance of the different species of this genus.

  18. Genomic and phenotypic characterization of the species Acinetobacter venetianus

    Science.gov (United States)

    Fondi, Marco; Maida, Isabel; Perrin, Elena; Orlandini, Valerio; La Torre, Laura; Bosi, Emanuele; Negroni, Andrea; Zanaroli, Giulio; Fava, Fabio; Decorosi, Francesca; Giovannetti, Luciana; Viti, Carlo; Vaneechoutte, Mario; Dijkshoorn, Lenie; Fani, Renato

    2016-01-01

    Crude oil is a complex mixture of hydrocarbons and other organic compounds that can produce serious environmental problems and whose removal is highly demanding in terms of human and technological resources. The potential use of microbes as bioremediation agents is one of the most promising fields in this area. Members of the species Acinetobacter venetianus have been previously characterized for their capability to degrade n-alkanes and thus may represent interesting model systems to implement this process. Although a preliminary experimental characterization of the overall hydrocarbon degradation capability has been performed for five of them, to date, the genetic/genomic features underlying such molecular processes have not been identified. Here we have integrated genomic and phenotypic information for six A. venetianus strains, i.e. VE-C3, RAG-1T, LUH 13518, LUH 7437, LUH 5627 and LUH 8758. Besides providing a thorough description of the A. venetianus species, these data were exploited to infer the genetic features (presence/absence patterns of genes) and the short-term evolutionary events possibly responsible for the variability in n-alkane degradation efficiency of these strains, including the mechanisms of interaction with the fuel droplet and the subsequent catabolism of this pollutant. PMID:26902269

  19. Genomic and phenotypic characterization of the species Acinetobacter venetianus.

    Science.gov (United States)

    Fondi, Marco; Maida, Isabel; Perrin, Elena; Orlandini, Valerio; La Torre, Laura; Bosi, Emanuele; Negroni, Andrea; Zanaroli, Giulio; Fava, Fabio; Decorosi, Francesca; Giovannetti, Luciana; Viti, Carlo; Vaneechoutte, Mario; Dijkshoorn, Lenie; Fani, Renato

    2016-02-23

    Crude oil is a complex mixture of hydrocarbons and other organic compounds that can produce serious environmental problems and whose removal is highly demanding in terms of human and technological resources. The potential use of microbes as bioremediation agents is one of the most promising fields in this area. Members of the species Acinetobacter venetianus have been previously characterized for their capability to degrade n-alkanes and thus may represent interesting model systems to implement this process. Although a preliminary experimental characterization of the overall hydrocarbon degradation capability has been performed for five of them, to date, the genetic/genomic features underlying such molecular processes have not been identified. Here we have integrated genomic and phenotypic information for six A. venetianus strains, i.e. VE-C3, RAG-1(T), LUH 13518, LUH 7437, LUH 5627 and LUH 8758. Besides providing a thorough description of the A. venetianus species, these data were exploited to infer the genetic features (presence/absence patterns of genes) and the short-term evolutionary events possibly responsible for the variability in n-alkane degradation efficiency of these strains, including the mechanisms of interaction with the fuel droplet and the subsequent catabolism of this pollutant.

  20. Pregnancy and Perinatal Outcomes Associated with Acinetobacter baumannii Infection

    Directory of Open Access Journals (Sweden)

    Mai He

    2013-05-01

    Full Text Available Objective - To determine perinatal and pregnancy outcomes of Acinetobacter baumannii infection using clinicopathologic material from pregnant women, neonates, and perinatal postmortem examinations with positive cultures. Study Design - This is a retrospective record review with placental and postmortem examination. Results - During a 5-year period, 40 positive cultures were found. Three pregnancies with positive cultures close in the peripartum period were all associated with adverse outcomes including spontaneous abortion, preterm labor, and one full-term birth with histological chorioamnionitis. Two positive cultures were found in preterm neonates in the neonatal intensive care unit. Two of three cases of perinatal death grew pure cultures from blood and/or fetal tissue with placental or fetal examination demonstrating evidence of infection/inflammation with fetal inflammatory response. Conclusion - This is the first case series report of A. baumannii-positive cultures in maternal, fetal, and neonatal specimen, with histopathologic evidence of infection. The results suggest a significant role of A. baumannii infection in adverse pregnancy and perinatal outcomes.

  1. First steps towards a vaccine against Acinetobacter baumannii.

    Science.gov (United States)

    Garcia-Quintanilla, Meritxell; Pulido, Marina R; McConnell, Michael J

    2013-01-01

    Acinetobacter baumannii has become an important cause of human infections, most notably in the hospital setting. In addition, the global dissemination of multidrug resistant strains has complicated effective antibiotic therapy of infections produced by this pathogen, necessitating the development of novel treatment and prevention strategies. Active and passive immunization approaches have begun to be explored in experimental animal models as potential alternative therapies for A. baumannii. In the present review, we discuss the advantages and disadvantages of each therapeutic strategy with respect to A. baumannii infections, and summarize the recent studies that have explored these approaches. The single antigen candidates that have been tested include, the outer membrane protein OmpA, the membrane transporter Ata, the biofilm-associated protein Bap, the K1 capsular polysaccharide and the membrane associated polysaccharide poly-N-acetyl-β -(1-6)-glucosamine. Strategies employing multicomponent antigens include inactivated whole cells, outer membrane complexes and outer membrane vesicles. The strengths and limitations of each approach are discussed and the challenges that remain to be addressed for successful A. baumannii vaccine development are highlighted.

  2. Tetracyclines for multidrug-resistant Acinetobacter baumannii infections.

    Science.gov (United States)

    Falagas, Matthew E; Vardakas, Konstantinos Z; Kapaskelis, Anastasios; Triarides, Nikolaos A; Roussos, Nikolaos S

    2015-05-01

    Multidrug-resistant (MDR) Acinetobacter baumannii infections have emerged as a serious threat worldwide. As novel agents have yet to be developed, understanding the effectiveness and safety of older antibiotics has become a priority. The purpose of this systematic review was to summarise the available clinical evidence on the use of tetracyclines for the treatment of A. baumannii infections. Ten retrospective studies regarding doxycycline and minocycline for the treatment of 185 A. baumannii infections (of which 65.4% were respiratory infections and 13% were bloodstream infections) in 156 patients were available. In most cases (86.4%), tetracyclines were administered in combination with another agent. The usual dosage of doxycycline or minocycline was 100mg intravenous or per os twice daily (usually with a 200mg loading dose for minocycline). Clinical success was achieved in 120 (76.9%) of 156 patients; in 87 (71.9%) of 121 respiratory infections and in 21 (87.5%) of 24 bloodstream infections. Twenty-two deaths occurred in 100 recorded cases. Microbiological eradication was attained in 72 (71.3%) of 101 available cases and documented microbiological eradication was reached in 59 (66.3%) of 89 available cases. Adverse events were noted in only 1 of 88 cases. Overall, although tetracycline-containing regimens showed encouraging results, more data from larger comparative trials are required to establish a role for these antibiotics in the treatment of MDR A. baumannii infections.

  3. Biodegradation of methyl parathion by Acinetobacter radioresistens USTB-04

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Biodegradation of methyl parathion (MP), a widely used organophosphorus pesticide, was investigated using a newly isolated bacterium strain Acinetobacter radioresistens USTB-04. MP at an initial concentration of 1200 mg/L could be totally biodegraded by A. radioresistens USTB-04 as the sole carbon source less than 4 d in the presence of phosphate and urea as phosphorus and nitrogen sources, respectively. Biodegradation of MP was also achieved using cell-free extract of A. radioresistens USTB-04. MP at an initial concentration of 130 mg/L was completely biodegraded in 2 h in the presence of cell-free extract with a protein concentration of 148.0mg/L, which was increased with the increase of pH from 5.0 to 8.0. Contrary to published reports, no intermediate or final degradation metabolites of MP could be observed. Thus we suggest that the cleavage of C-C bond on the benzene ring other than P-O bond may be the biodegradation pathway of MP by A. radioresistens USTB-04.

  4. Stereochemical insignificance discovered in Acinetobacter baumannii quorum sensing.

    Directory of Open Access Journals (Sweden)

    Amanda L Garner

    Full Text Available Stereochemistry is a key aspect of molecular recognition for biological systems. As such, receptors and enzymes are often highly stereospecific, only recognizing one stereoisomer of a ligand. Recently, the quorum sensing signaling molecules used by the nosocomial opportunistic pathogen, Acinetobacter baumannii, were identified, and the primary signaling molecule isolated from this species was N-(3-hydroxydodecanoyl-L-homoserine lactone. A plethora of bacterial species have been demonstrated to utilize 3-hydroxy-acylhomoserine lactone autoinducers, and in virtually all cases, the (R-stereoisomer was identified as the natural ligand and exhibited greater autoinducer activity than the corresponding (S-stereoisomer. Using chemical synthesis and biochemical assays, we have uncovered a case of stereochemical insignificance in A. baumannii and provide a unique example where stereochemistry appears nonessential for acylhomoserine lactone-mediated quorum sensing signaling. Based on previously reported phylogenetic studies, we suggest that A. baumannii has evolutionarily adopted this unique, yet promiscuous quorum sensing system to ensure its survival, particularly in the presence of other proteobacteria.

  5. Endemic Acinetobacter baumannii in a New York hospital.

    Directory of Open Access Journals (Sweden)

    Scott A Weisenberg

    Full Text Available BACKGROUND: Acinetobacter baumannii is an increasingly multidrug-resistant (MDR cause of hospital-acquired infections, often associated with limited therapeutic options. We investigated A. baumannii isolates at a New York hospital to characterize genetic relatedness. METHODS: Thirty A. baumannii isolates from geographically-dispersed nursing units within the hospital were studied. Isolate relatedness was assessed by repetitive sequence polymerase chain reaction (rep-PCR. The presence and characteristics of integrons were assessed by PCR. Metabolomic profiles of a subset of a prevalent strain isolates and sporadic isolates were characterized and compared. RESULTS: We detected a hospital-wide group of closely related carbapenem resistant MDR A. baumannii isolates. Compared with sporadic isolates, the prevalent strain isolates were more likely to be MDR (p = 0.001. Isolates from the prevalent strain carried a novel Class I integron sequence. Metabolomic profiles of selected prevalent strain isolates and sporadic isolates were similar. CONCLUSION: The A. baumannii population at our hospital represents a prevalent strain of related MDR isolates that contain a novel integron cassette. Prevalent strain and sporadic isolates did not segregate by metabolomic profiles. Further study of environmental, host, and bacterial factors associated with the persistence of prevalent endemic A. baumannii strains is needed to develop effective prevention strategies.

  6. Transcriptome Remodeling of Acinetobacter baumannii during Infection and Treatment

    Science.gov (United States)

    Wright, Meredith S.; Jacobs, Michael R.; Bonomo, Robert A.

    2017-01-01

    ABSTRACT Acinetobacter baumannii is an increasingly common multidrug-resistant pathogen in health care settings. Although the genetic basis of antibiotic resistance mechanisms has been extensively studied, much less is known about how genetic variation contributes to other aspects of successful infections. Genetic changes that occur during host infection and treatment have the potential to remodel gene expression patterns related to resistance and pathogenesis. Longitudinal sets of multidrug-resistant A. baumannii isolates from eight patients were analyzed by RNA sequencing (RNA-seq) to identify differentially expressed genes and link them to genetic changes contributing to transcriptional variation at both within-patient and population levels. The number of differentially expressed genes among isolates from the same patient ranged from 26 (patient 588) to 145 (patient 475). Multiple patients had isolates with differential gene expression patterns related to mutations in the pmrAB and adeRS two-component regulatory system genes, as well as significant differences in genes related to antibiotic resistance, iron acquisition, amino acid metabolism, and surface-associated proteins. Population level analysis revealed 39 genetic regions with clade-specific differentially expressed genes, for which 19, 8, and 3 of these could be explained by insertion sequence mobilization, recombination-driven sequence variation, and intergenic mutations, respectively. Multiple types of mutations that arise during infection can significantly remodel the expression of genes that are known to be important in pathogenesis. PMID:28270585

  7. Once-Daily Amikacin Dosing in Burn Patients Treated with Continuous Venovenous Hemofiltration

    Science.gov (United States)

    2011-10-01

    previously documented inaccuracies with the Vitek 2 instrument (1), all Acinetobacter baumannii isolates reported as susceptible to amikacin were confirmed...64 Acinetobacter baumannii (35) 39.1% 23 64/64 Other Enterobacteriaciae (43) Stenotrophomonas maltophilia (11), Enterobacter aerogenes (9...al. 2010. Aminoglycoside resistance and susceptibility testing errors in Acinetobacter baumannii -calcoaceticus complex. J. Clin. Microbiol. 48:1132

  8. Rapid Dispersion of Polymicrobial Wound Biofilms with Depolymerase Enzymes

    Science.gov (United States)

    2012-11-01

    Gram-negative bacteria including Acinetobacter baumannii -calcoaceticus complex, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Additionally...composition and linkage analysis. Sample ID: BAA1605 Source: EPS carbohydrate from Acinetobacter baumannii 04/10/12 ~7 mg Sample ID...BAA1878 Source: EPS carbohydrate from Acinetobacter baumannii 04/10/12 ~5 mg Sample ID: 700831 Source: EPS carbohydrate from Klebsiella

  9. Comparison of PCR/Electron Spray Ionization-Time-of-Flight-Mass Spectrometry versus Traditional Clinical Microbiology for Active Surveillance of Organisms Contaminating High-Use Surfaces in a Burn Intensive Care Unit, an Orthopedic Ward and Healthcare Workers

    Science.gov (United States)

    2012-10-10

    Enterobacter spp., Streptococcus spp. (68% viridans group), Pseudomonas aeruginosa, and Acinetobacter baumannii -calcoaceticus complex; the proportions of these...Staphylococcus aureus and Acinetobacter baumannii on computer interface surfaces of hospital wards and association with clinical isolates. BMC Infect Dis 2009, 9...Cursino MR, Sinto S: Environmental contamination by multidrug resistant Acinetobacter baumannii in an intensive care unit. Infect Control Hosp Epidemiol

  10. Host-microbe interactions that shape the pathogenesis of Acinetobacter baumannii infection.

    Science.gov (United States)

    Mortensen, Brittany L; Skaar, Eric P

    2012-09-01

    Acinetobacter baumannii is an opportunistic pathogen that has emerged as a prevalent source of nosocomial infections, most frequently causing ventilator-associated pneumonia. The emergence of pan-drug resistant strains magnifies the problem by reducing viable treatment options and effectively increasing the mortality rate associated with Acinetobacter infections. In light of this rising threat, research on A. baumannii epidemiology, antibiotic resistance, and pathogenesis is accelerating. The recent development of both in vitro and in vivo models has enabled studies probing the host-Acinetobacter interface. Bacterial genetic screens and comparative genomic studies have led to the identification of several A. baumannii virulence factors. Additionally, investigations into host defence mechanisms using animal models or cell culture have provided insight into the innate immune response to infection. This review highlights some of the key attributes of A. baumannii virulence with an emphasis on bacterial interactions with the innate immune system.

  11. Identification of KPC-Producing Pseudomonas Aeruginosa and Acinetobacter Baumanniiin a Burned Infant: A Case Report

    Directory of Open Access Journals (Sweden)

    Abdolaziz Rastegar Lari

    2012-03-01

    Full Text Available The objective of this study was to determine the phenotypic characteristics of KPC-producing Pseudomonas aeruginosa and Acinetobacter baumannii isolates. A case report study was performed at a tertiary burn care centre in Tehran, Iran. Nine isolates of Pseudomonas aeruginosa and Acinetobacter baumannii from a hospitalized case were isolated. The identity of isolates was confirmed and their antibiotic susceptibility testing was performed. Eight out of nine Pseudomonas aeruginosa and Acinetobacter baumannii isolates were resistant to Imipenem. Three out of 8 imipenem resistant isolates were also positive for KPC test. Findings of this study highlight the importance of implementation of an effective infection control strategy in order to prevent and reduce the emergence and spread of gram negative Carbapenemase-producing organisms in Iran.

  12. Antimicrobial susceptibility profile of Acinetobacter species isolated from blood cultures in two Japanese university hospitals.

    Science.gov (United States)

    Kishii, Kozue; Kikuchi, Ken; Yoshida, Atsushi; Okuzumi, Katsuko; Uetera, Yushi; Yasuhara, Hiroshi; Moriya, Kyoji

    2014-02-01

    Carbapenem-resistant Acinetobacter baumannii has rapidly spread worldwide. This study investigated antibiotic susceptibility and genotypic resistance of 123 consecutive blood culture isolates of Acinetobacter species collected between 2003 and 2011 in two Japanese hospitals. The isolates were assigned to 13 species. Carbapenem resistance was detected in four isolates. Only one A. baumannii isolate had blaOXA-23 together with ISAba1; the remaining three isolates had IMP-1 metallo-β-lactamase. Quinolone resistance was detected in five isolates that had point mutations in the quinolone resistance-determining region. The predominance of various non-A. baumannii species and low prevalence of carbapenem resistance among blood culture isolates of Acinetobacter species in two Japanese hospitals were confirmed.

  13. Diversity Within the O-linked Protein Glycosylation Systems of Acinetobacter Species

    DEFF Research Database (Denmark)

    Scott, N. E.; Kinsella, R. L.; Edwards, A. V. G.

    2014-01-01

    The opportunistic human pathogen Acinetobacter baumannii is a concern to health care systems worldwide because of its persistence in clinical settings and the growing frequency of multiple drug resistant infections. To combat this threat, it is necessary to understand factors associated...... with disease and environmental persistence of A. baumannii. Recently, it was shown that a single biosynthetic pathway was responsible for the generation of capsule polysaccharide and O-linked protein glycosylation. Because of the requirement of these carbohydrates for virulence and the non-template driven...... nature of glycan biogenesis we investigated the composition, diversity, and properties of the Acinetobacter glycoproteome. Utilizing global and targeted mass spectrometry methods, we examined 15 strains and found extensive glycan diversity in the O-linked glycoproteome of Acinetobacter. Comparison...

  14. Early dissemination of OXA-72-producing Acinetobacter baumannii strain in Colombia: a case report.

    Science.gov (United States)

    Saavedra, Sandra Yamile; Cayô, Rodrigo; Gales, Ana Cristina; Leal, Aura Lucia; Saavedra, Carlos Humberto

    2014-01-01

    Nosocomial infections caused by carbapenem-resistant Acinetobacter baumannii isolates have reached epidemic levels in past decades. Currently this microorganism is responsible for outbreaks of difficult eradication and with high mortality rates worldwide. We herein report a rare case of an OXA-72-producing A. baumannii isolate colonizing a 47-year-old male patient with peritonitis due to abdominal stab wound, four years earlier than the first report of this carbapenemase in Acinetobacter pittii in Colombia. Although OXA-72 presents a low prevalence compared with OXA-23, our study demonstrated that A. baumannii isolates carrying the blaOXA-72 gene were present in the hospital environment in Colombia and could act as a reservoir for further spread to other Acinetobacter species, like A. pittii, causing carbapenem-resistance.

  15. CLINICAL AND ANTIMICROBIAL PROFILE OF ACINETOBACTER SPECIES AT TERTIARY CARE HOSPITAL IN CENTRAL INDIA

    Directory of Open Access Journals (Sweden)

    Apoorva

    2014-07-01

    Full Text Available BACKGROUND: Acinetobacter are the “superbugs” of the modern hospital environment causing significant proportion of infections and in particular nosocomial infections with high mortality rates. The aim of this study was to isolate Acinetobacter species from clinical specimens and to study the antimicrobial susceptibility pattern of Acinetobacter isolates. MATERIAL AND METHODS: Two hundred and four clinical isolates of Acinetobacter species were processed for species identification by standard microbiological procedures. Antimicrobial susceptibility of these isolates was performed by Kirby-Bauer disc diffusion method. RESULTS: Out of 204 Acinetobacter isolates, 125(61.27% isolates were from ICU and 79(38.72% were from general wards. A baumannii was the most common species isolated (74.50%, followed by A.lwoffii (24.50% and A.haemolyticus (0.98%. A.baumannii showed maximum sensitivity to IPM (52.63% followed by MRP(36.18%, AK(28.28%, PIT(26.31%, TCC(21.71%, CIP(21.05% G(17.76% and COT(05.26%. Maximum resistance was observed to CTX(1.31% followed by CAZ(1.97%, CTR(1.97% and CPM(1.97% respectively. A.lwoffii showed maximum sensitivity to IPM(94% followed by AK(90%, and MRP(84%. Statistically significant difference (p value <0.001 was noticed between antibiotic resistance of A.baumannii and A.lwoffii. CONCLUSION: Continued surveillance of drug resistant strains in ICUs, combined with preventive measures remains absolutely essential to prevent or limit the spread of Acinetobacter species in hospital.

  16. In vitro susceptibility pattern of acinetobacter species to commonly used cephalosporins, quinolones, and aminoglycosides

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    Prashanth K

    2004-01-01

    Full Text Available PURPOSE: Acinetobacter spp. is an emerging important nosocomial pathogen. Clinical isolates of this genus are often resistant to many antibiotics. The in vitro susceptibility of Acinetobacter isolates obtained from patients were tested for currently used antibiotics. In addition, the study aimed at biotyping of Acinetobacter baumannii. METHODS: A total of 66 isolates were phenotypically characterised through a large panel of 25 carbon assimilation tests and susceptibility through disc diffusion method with 10 antimicrobial agents were tested. MICs were determined only for second line broad-spectrum drugs such as cefotaxime, ceftazidime, amikacin, ciprofloxacin, and ofloxacin using NCCLS guidelines. RESULTS: Multiple drug resistance (MDR was only witnessed in A. baumannii and not in other Acinetobacter species. Aminoglycosides such as amikacin, netilmicin were most active against the MDR isolates tested (60% susceptibility. Ceftazidime was more active than cefotaxime. MDR A. baumannii strains were susceptible only to amikacin, netilmicin and ceftadizime. Ciprofloxacin had poor activity irrespective of isolates belonging to different DNA groups tested (58% resistance overall, 79% among A. baumannii. Strains of Biotypes 6 and 19 of A. baumannii showed broader resistance than those of biotype 10 and others. CONCLUSIONS: Strains of A. baumannii from patients in our hospital, were generally more resistant to quinolones, -lactam antibiotics, first and second generation cephalosporins and partially resistant to third generation cephalosporins and aminoglycosides. The strains belonging to other DNA groups of Acinetobacter were comparatively less resistant than A.baumannii, except ciprofloxacin. This study suggests that, a combination therapy, using a third generation cephalosporin and amikacin, would be best choice for treating Acinetobacter infections.

  17. Short communication: Genetic characterization of antimicrobial resistance in Acinetobacter isolates recovered from bulk tank milk.

    Science.gov (United States)

    Tamang, M D; Gurung, M; Nam, H M; Kim, S R; Jang, G C; Jung, S C; Lim, S K

    2014-02-01

    A total of 176 Acinetobacter isolates, including 57 Acinetobacter baumannii originally obtained from 2,287 bulk tank milk (BTM) samples in Korea was investigated for the genetic basis of antimicrobial resistance using molecular methods. In addition, the occurrence and cassette content of integrons were examined and the genetic diversity of A. baumannii strains identified was evaluated. Aminoglycoside-modifying enzyme genes were detected in 15 (88.2%) of the 17 aminoglycoside-resistant Acinetobacter isolates tested. The most common aminoglycoside-modifying enzyme gene identified was adenylyltransferase gene aadB (n = 9), followed by phosphotransferase genes aphA6 (n = 7) and aphA1 (n = 5). Of the 31 isolates resistant to tetracycline, tet(39) was detected in 20 of them. The genetic basis of resistance to sulfonamide was identified in 15 (53.6%) of 28 trimethoprim-sulfamethoxazole-resistant isolates and 9 (32.1%) of them carried both sul1 and sul2 genes. A blaADC-7-like gene was detected in 1 β-lactam-resistant A. baumannii. Furthermore, class 1 integron was identified in 11 Acinetobacter isolates. Two gene cassettes dfrA15, conferring resistance to trimethoprim, and aadA2, conferring resistance to aminoglycosides, were identified in 8 Acinetobacter isolates. None of the isolates was positive for class 2 or class 3 integrons. Pulsed-field gel electrophoresis revealed that most of the A. baumannii strains from BTM samples were genetically diverse, indicating that the occurrence of A. baumannii strains in BTM was not the result of dissemination of a single clone. Elucidation of resistance mechanisms associated with the resistance phenotype and a better understanding of resistance genes may help in the development of strategies to control infections, such as mastitis, and to prevent further dissemination of antibiotic resistance genes. To the best of our knowledge, this is the first report of molecular characterization of antimicrobial-resistant Acinetobacter spp. from

  18. Prognostic differences between VAP from Acinetobacter baumanii and VAP from other microorganisms

    Science.gov (United States)

    Di Bonito, Marianna; Caiazzo, Simona; Iannazzone, Marta; Miccichè, Viviana; De Marco, Giuseppe; De Robertis, Edoardo; Tufano, Rosalba; Piazza, Ornella

    2012-01-01

    Nosocomial infection, in particular pneumonia, is an important risk factor for hospital mortality and morbidity. Acinetobacter baumanii is a common multi-resistant microorganism responsible of Ventilator Associated Pneumonia (VAP). Currently Colistin is a rescue therapy for this pathogen. The purpose of this retrospective study is to compare the outcome of VAP caused by Acinetobacter baumanii and VAP from other microorganisms in critical patients. Comorbidity, prognostic scores, mortality and eradication frequency did not turn out significantly different between the two study groups. Colistin safety was tested. PMID:23905048

  19. Neglected Fournier's Gangrene Caused by Acinetobacter baumannii: A Rare Case Report

    Science.gov (United States)

    Emre, Arif; Sertkaya, Mehmet; Duman, Yakup; Kale, Ilhami Taner

    2016-01-01

    Fournier's gangrene, rare but life threatening disease, is characterized by an acute necrotic infection of the scrotum, penis, or perineum. Fournier's gangrene is a mixed infection caused by both aerobic and anaerobic bacteria. Fournier's gangrene caused by multidrug resistant Acinetobacter baumannii have been reported rarely. The mainstay of treatment is prompt recognition and a combination of antibiotics with radical debridement. We describe a case of a 56-year-old male patient presenting with neglected Fournier's gangrene caused by Acinetobacter baumannii. Many treatment modalities including broad-spectrum antibiotics, aggressive debridement, negative pressure wound therapy, diversion colostomy, and partial-thickness skin grafts were applied to save the patient's life. PMID:27725892

  20. Biofilm formation at the solid-liquid and air-liquid interfaces by Acinetobacter species

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    Seifert Harald

    2011-01-01

    Full Text Available Abstract Background The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections. Among them, Acinetobacter baumannii has emerged as the most common pathogenic species involved in hospital-acquired infections. One reason for this emergence may be its persistence in the hospital wards, in particular in the intensive care unit; this persistence could be partially explained by the capacity of these microorganisms to form biofilm. Therefore, our main objective was to study the prevalence of the two main types of biofilm formed by the most relevant Acinetobacter species, comparing biofilm formation between the different species. Findings Biofilm formation at the air-liquid and solid-liquid interfaces was investigated in different Acinetobacter spp. and it appeared to be generally more important at 25°C than at 37°C. The biofilm formation at the solid-liquid interface by the members of the ACB-complex was at least 3 times higher than the other species (80-91% versus 5-24%. In addition, only the isolates belonging to this complex were able to form biofilm at the air-liquid interface; between 9% and 36% of the tested isolates formed this type of pellicle. Finally, within the ACB-complex, the biofilm formed at the air-liquid interface was almost 4 times higher for A. baumannii and Acinetobacter G13TU than for Acinetobacter G3 (36%, 27% & 9% respectively. Conclusions Overall, this study has shown the capacity of the Acinetobacter spp to form two different types of biofilm: solid-liquid and air-liquid interfaces. This ability was generally higher at 25°C which might contribute to their persistence in the inanimate hospital environment. Our work has also demonstrated for the first time the ability of the members of the ACB-complex to form biofilm at the air-liquid interface, a feature that was not

  1. Relationship between antimicrobial resistance and aminoglycoside-modifying enzyme gene expressions in Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    SHI Wei-feng; JIANG Jian-ping; MI Zu-huang

    2005-01-01

    Background Acinetobacter baumannii is one of the main gram-negative bacilli in clinical practice. Nosocomial infections caused by multi-drug resistance Acinetobacter baumannii is very difficult to treat. This study was designed to investigate the antimicrobial resistance characteristics and four resistant gene expressions of aminoglycoside-modifying enzymes including N-acetyltransferases and O-phosphotransferases in Acinetobacter baumannii. Methods Bacterial identification and antimicrobial susceptibility test were performed by PhoenixTM system in 247 strains of Acinetobacter baumannii. Minimal inhibitory concentrations (MICs) of seven aminoglycosides including gentamicin, amikacin, kanamycin, tobramycin, netilmicin, neomycin and streptomycin in 15 strains of multi-drug resistant Acinetobacter baumannii were detected by agar dilution. Four aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction (PCR) and verified by DNA sequencer.Results The resistance rates of 247 strains of Acinetobacter baumannii against cefotaxime, levofloxacin, piperacillin, aztreonam, tetracycline, ciprofloxacin and chloramphenicol were more than 50%. Imipenem and meropenem showed high antibacterial activities with resistance rates of 3.2% and 4.1%. MIC50 and MIC90 of gentamicin, amikacin, streptomycin and kanamycin in 15 strains of multi-drug resistant Acinetobacter baumanii were all more than 1024 mg/L, and the resistance rates were 100%, 100%, 100% and 93.3%, respectively. But their resistance rates to tobramycin, netilmicin and neomycin were 86.7%, 93.3% and 46.7%, respectively. Three modifying enzyme genes, including aacC1, aacC2 and aacA4 genes, were found in 15 strains, but aphA6 had not been detected. Their positive rates were 93.3%, 20.0% and 20.0%, respectively. These three genes existed simultaneously in No.19 strain. Nucleotide sequences of aacC1, aacC2 and aacA4 genes shared 100%, 97.9% and 99.7% identities with GenBank genes (AY307113, S68058 and AY

  2. Genome sequencing and annotation of Acinetobacter guillouiae strain MSP 4-18

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    Nitin Kumar Singh

    2014-12-01

    Full Text Available The genus Acinetobacter consists of 31 validly published species ubiquitously distributed in nature and primarily associated with nosocomial infection. We report the 4.8 Mb genome of Acinetobacter guillouiae MSP 4-18, isolated from a mangrove soil sample from Parangipettai (11°30′N, 79°47′E, Tamil Nadu, India. The draft genome of A. guillouiae MSP 4-18 has a G + C content of 38.0% and includes 3 rRNA genes (5S, 23S, 16S and 69 aminoacyl-tRNA synthetase genes.

  3. Regional differences and trends in antimicrobial susceptibility of Acinetobacter baumannii.

    Science.gov (United States)

    Lob, Sibylle H; Hoban, Daryl J; Sahm, Daniel F; Badal, Robert E

    2016-04-01

    Acinetobacter baumannii, although representing a small percentage of Gram-negative bacilli isolates in intra-abdominal infections (IAIs) and urinary tract infections (UTIs), is frequently multidrug-resistant (MDR) and can pose difficult therapeutic challenges. From 2011 to 2014, 2337 A. baumannii were collected from IAIs and UTIs at 453 hospital sites in 48 countries as part of the SMART ongoing surveillance initiative. Current susceptibility and multidrug resistance, defined as resistance to at least three of the tested drug classes, were determined in a subset of 1011 isolates from 2013 to 2014. A. baumannii comprised 0.7-4.6% of all aerobic and facultative Gram-negative bacilli isolated in six global regions. MDR rates were lowest in North America (47%) and highest in Europe and the Middle East (>93%), with higher rates in ICUs than in non-ICU wards in almost all regions. Antimicrobial susceptibility profiles varied by region but resistance was high everywhere, with no drug inhibiting >70% of A. baumannii isolates in any region. Susceptibility to imipenem was highest in North America (64%) and lowest in Europe and the Middle East (≤11%). Amikacin overall was the most active of the studied agents, including against MDR isolates (of which 11-38% were susceptible). Trend analysis of only those countries that contributed isolates in each study year (2011-2014) demonstrated an increasing trend in MDR rates in the Middle East as well as decreasing susceptibility to several single antimicrobial agents in Africa, Europe and the Middle East. These patterns and trends can help direct antimicrobial therapy and infection control efforts.

  4. Inverse PCR for subtyping of Acinetobacter baumannii carrying ISAba1.

    Science.gov (United States)

    Kim, Shukho; Park, Yun-Ju; Kim, Jungmin

    2016-05-01

    Acinetobacter baumannii has been prevalent in nosocomial infections, often causing outbreaks in intensive care units. ISAba1 is an insertion sequence that has been identified only in A. baumannii and its copy number varies among strains. It has been reported that ISAba1 provides a promoter for bla(OXA-51-like), bla(OXA-23-like), and bla(ampC), which are associated with the resistance of A. baumannii to carbapenems and cephalosporins. The main purpose of this study was to develop a novel inverse PCR method capable of typing A. baumannii strains. The method involves three major steps: cutting of genomic DNA with a restriction enzyme, ligation, and PCR. In the first step, bacterial genomic DNA was digested with DpnI. In the second step, the digested genomic DNAs were ligated to form intramolecular circular DNAs. In the last step, the ligated circular DNAs were amplified by PCR with primers specific for ISAba1 and the amplified PCR products were electrophoresed. Twenty-two clinical isolates of A. baumannii were used for the evaluation of the inverse PCR (iPCR) typing method. Dendrogram analysis revealed two major clusters, similar to pulsed-field gel electrophoresis (PFGE) results. Three ISAba1-associated genes--bla(ampC), bla(OXA-66-like), and csuD--were amplified and detected in the clinical isolates. This novel iPCR typing method is comparable to PFGE in its ability to discriminate A. baumannii strains, and is a promising molecular epidemiological tool for investigating A. baumannii carrying ISAba1.

  5. Acinetobacter baumannii: biology and drug resistance - role of carbapenemases.

    Science.gov (United States)

    Nowak, Pawel; Paluchowska, Paulina

    2016-01-01

    Acinetobacter baumannii is a Gram-negative, glucose-non-fermenting, oxidase-negative coccobacillus, most commonly associated with the hospital settings. The ability to survive in adverse environmental conditions as well as high level of natural and acquired antimicrobial resistance make A. baumannii one of the most important nosocomial pathogens. While carbapenems have long been considered as antimicrobials of last-resort, the rates of clinical A. baumannii strains resistant to these antibiotics are increasing worldwide. Carbapenem resistance among A. baumannii is conferred by coexisting mechanisms including: decrease in permeability of the outer membrane, efflux pumps, production of beta-lactamases, and modification of penicillin-binding proteins. The most prevalent mechanism of carbapenem resistance among A. baumannii is associated with carbapenem-hydro-lysing enzymes that belong to Ambler class D and B beta-lactamases. In addition, there have also been reports of resistance mediated by selected Ambler class A carbapenemases among A. baumannii strains. Resistance determinants in A. baumannii are located on chromosome and plasmids, while acquisition of new mechanisms can be mediated by insertion sequences, integrons, transposons, and plasmids. Clinical relevance of carbapen-em resistance among strains isolated from infected patients, carriers and hospital environment underlines the need for carbapenemase screening. Currently available methods vary in principle, accuracy and efficiency. The techniques that deserve particular attention belong to both easily accessible unsophisticated methods as well as advanced techniques based on mass spectrometry or molecular biology. While carbapenemases limit the therapeutic options in A. baumannii infections, studies concerning novel beta-lactamase inhibitors offer a new insight into effective therapy.

  6. Antibiotic modulation of capsular exopolysaccharide and virulence in Acinetobacter baumannii.

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    Edward Geisinger

    2015-02-01

    Full Text Available Acinetobacter baumannii is an opportunistic pathogen of increasing importance due to its propensity for intractable multidrug-resistant infections in hospitals. All clinical isolates examined contain a conserved gene cluster, the K locus, which determines the production of complex polysaccharides, including an exopolysaccharide capsule known to protect against killing by host serum and to increase virulence in animal models of infection. Whether the polysaccharides determined by the K locus contribute to intrinsic defenses against antibiotics is unknown. We demonstrate here that mutants deficient in the exopolysaccharide capsule have lowered intrinsic resistance to peptide antibiotics, while a mutation affecting sugar precursors involved in both capsule and lipopolysaccharide synthesis sensitizes the bacterium to multiple antibiotic classes. We observed that, when grown in the presence of certain antibiotics below their MIC, including the translation inhibitors chloramphenicol and erythromycin, A. baumannii increases production of the K locus exopolysaccharide. Hyperproduction of capsular exopolysaccharide is reversible and non-mutational, and occurs concomitantly with increased resistance to the inducing antibiotic that is independent of the presence of the K locus. Strikingly, antibiotic-enhanced capsular exopolysaccharide production confers increased resistance to killing by host complement and increases virulence in a mouse model of systemic infection. Finally, we show that augmented capsule production upon antibiotic exposure is facilitated by transcriptional increases in K locus gene expression that are dependent on a two-component regulatory system, bfmRS. These studies reveal that the synthesis of capsule, a major pathogenicity determinant, is regulated in response to antibiotic stress. Our data are consistent with a model in which gene expression changes triggered by ineffectual antibiotic treatment cause A. baumannii to transition

  7. Kinetic properties and inhibition of Acinetobacter glutaminase-asparaginase.

    Science.gov (United States)

    Steckel, J; Roberts, J; Philips, F S; Chou, T C

    1983-03-15

    Kinetic parameters, substrate specificity and exclusivity of ligands at binding sites of L-glutaminase-L-asparaginase purified from Acinetobacter glutaminasificans were studied in order to gain knowledge about the dual activities of this enzyme and its inhibition by structural analogs. Both L-glutamine and L-asparagine, which showed similar Km (4 approximately 7 X 10(-5) M) and Vmax (molecular activity 1.0 min-1) values, were competitive with each other for the substrate binding site. The products, L-glutamic acid and L-aspartic acid, showed competitive inhibition with respect to either L-glutamine or L-asparagine as substrates. Multiple inhibition of the glutaminase activity by L-glutamic acid and L-aspartic acid indicated that these ligands are mutually exclusive at the product-releasing site. The initial rates of both of the enzyme's activities were competitively inhibited by the following inhibitors (in rates of both of the enzyme's activities were competitively inhibited by the following inhibitors (in decreasing order of activity): 6-diazo-5-oxo-L-norleucine (DON), L-methionine sulfoximine, azaserine, and Acivicin. DON and azaserine inhibited both the asparaginase and glutaminase activities in a time-dependent and irreversible manner. The kinetic data suggest an ordered mechanism with glutamine or asparagine as the first substrate and glutamic acid or aspartic acid, respectively, as the last product. These results also suggest that a single mechanism and a single set of binding sites are responsible for catalyzing both of the enzyme's activities. The data also showed that succinylated enzyme, which has a 10-fold increase of plasma half-life in animals and humans and, thus, has benefit as a cancer chemotherapeutic agent, retained its catalytic activity and maintained Km and Vmax values similar to the native enzyme.

  8. A taxonomically unique Acinetobacter strain with proteolytic and hemolytic activities recovered from a patient with a soft tissue injury.

    Science.gov (United States)

    Almuzara, Marisa; Traglia, German Matías; Krizova, Lenka; Barberis, Claudia; Montaña, Sabrina; Bakai, Romina; Tuduri, Alicia; Vay, Carlos; Nemec, Alexandr; Ramírez, María Soledad

    2015-01-01

    A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter.

  9. The changing epidemiology of Acinetobacter spp. producing OXA carbapenemases causing bloodstream infections in Brazil: a BrasNet report.

    Science.gov (United States)

    Vasconcelos, Ana Tereza R; Barth, Afonso L; Zavascki, Alexandre P; Gales, Ana C; Levin, Anna S; Lucarevschi, Bianca R; Cabral, Blenda G; Brasiliense, Danielle M; Rossi, Flavia; Furtado, Guilherme H C; Carneiro, Irna Carla R S; da Silva, Juliana O; Ribeiro, Julival; Lima, Karla V B; Correa, Luci; Britto, Maria H; Silva, Mariama T; da Conceição, Marília L; Moreira, Marina; Martino, Marinês D V; de Freitas, Marise R; Oliveira, Maura S; Dalben, Mirian F; Guzman, Ricardo D; Cayô, Rodrigo; Morais, Rosângela; Santos, Sânia A; Martins, Willames M B S

    2015-12-01

    We evaluated the epidemiology of Acinetobacter spp. recovered from patients diagnosed with bloodstream infections in 9 tertiary hospitals located in all Brazilian geographic regions between April and August 2014. Although OXA-23-producing Acinetobacter baumannii clones were disseminated in most hospitals, it was observed for the first time the spread of OXA-72 among clonally related A. baumannii isolated from distinct hospitals. Interestingly, Acinetobacter pittii was the most frequent species found in a Northern region hospital. Contrasting with the multisusceptible profile displayed by A. pittii isolates, the tetracyclines and polymyxins were the only antimicrobials active against all A. baumannii isolates.

  10. Draft Genome Sequences of Clinical Isolates of Multidrug-Resistant Acinetobacter baumannii

    Science.gov (United States)

    Erickson, Keesha E.; Madinger, Nancy E.

    2017-01-01

    ABSTRACT We report here the draft genome sequences of two clinically isolated Acinetobacter baumannii strains. These samples were obtained from patients at the University of Colorado Hospital in 2007 and 2013 and encode an estimated 20 and 13 resistance genes, respectively. PMID:28153899

  11. Quorum sensing in Acinetobacter: with special emphasis on antibiotic resistance, biofilm formation and quorum quenching

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    Bindu Subhadra

    2016-02-01

    Full Text Available Acinetobacter is an important nosocomial, opportunistic human pathogen that is gradually gaining more attention as a major health threat worldwide. Quorum sensing (QS is a cell-cell communication system in which specific signaling molecules called autoinducers accumulate in the medium as the population density grows and control various physiological processes including production of virulence factors, biofilm and development of antibiotic resistance. The complex QS machinery in Acinetobacter is mediated by a two-component system which is homologous to the typical LuxI/LuxR system found in Gram-negative bacteria. This cell signaling system comprises of a sensor protein that functions as autoinducer synthase and a receptor protein which binds to the signal molecules, acyl homoserine lactones inducing a cascade of reactions. Lately, disruption of QS has emerged as an anti-virulence strategy with great therapeutic potential. Here, we depict the current understanding of the existing QS network in Acinetobacter and describe important anti-virulent strategies developed in order to effectively tackle this pathogen. In addition, the prospects of quorum quenching to control Acinetobacter infections is also been discussed.

  12. Ultraviolet C Light for Acinetobacter baumannii Wound Infections in Mice: Potential Use for Battlefield Wound Decontamination?

    Science.gov (United States)

    2012-01-01

    BACKGROUND: Since the beginning of the conflicts in the Middle East, US Army physicians have noted a high rate of multidrug-resistant Acinetobacter ... baumannii infections among US soldiers wounded and initially treated in Iraq. In this study, we investigated the use of ultraviolet C (UVC) light for

  13. Draft Genome of the Multidrug-Resistant Acinetobacter baumannii Strain A155 Clinical Isolate.

    Science.gov (United States)

    Arivett, Brock A; Fiester, Steven E; Ream, David C; Centrón, Daniela; Ramírez, Maria S; Tolmasky, Marcelo E; Actis, Luis A

    2015-03-26

    Acinetobacter baumannii is a bacterial pathogen with serious implications on human health, due to increasing reports of multidrug-resistant strains isolated from patients. Total DNA from the multidrug-resistant A. baumannii strain A155 clinical isolate was sequenced to greater than 65× coverage, providing high-quality contig assemblies.

  14. Acinetobacter lactucae sp. nov., isolated from iceberg lettuce (Asteraceae: Lactuca sativa).

    Science.gov (United States)

    Rooney, Alejandro P; Dunlap, Christopher A; Flor-Weiler, Lina B

    2016-09-01

    Strain NRRL B-41902T and three closely related strains were isolated from iceberg lettuce. The strain was found to consist of strictly aerobic, Gram-stain-negative rods that formed cocci in late stationary phase. 16S rRNA gene sequence analysis showed that strain NRRL B-41902T was most closely related to species within the genera Acinetobacter, and that a grouping of it and the three other closely related strains was most closely related to the type strain of Acinetobacter pittii, which was also confirmed through a phylogenomic analysis. Moreover, in silico DNA-DNA hybridization analysis revealed a substantial amount of genomic divergence (39.1 %) between strain NRRL B-41902T and the type strain of A. pittii, which is expected if the strains represent distinct species. Further phenotypic analysis revealed that strain NRRL B-41902T was able to utilize a combination of l-serine, citraconic acid and citramalic acid, which differentiated it from other, closely related Acinetobacter species. Therefore, strain NRRL B-41902T (=CCUG 68785T) is proposed as the type strain of a novel species, Acinetobacter lactucae sp. nov.

  15. Isolation and characterization of a novel n-alkane-degrading strain, Acinetobacter haemolyticus AR-46

    Energy Technology Data Exchange (ETDEWEB)

    Bihari, Z.; Balazs, M.; Bartos, P.; Kesserue, P.; Kiss, I.; Mecs, I. [Bay Zoltan Foundation for Applied Research, Szeged (Hungary). Inst. for Biotechnology; Pettko-Szandtner, A. [Hungarian Academy of Sciences, Szeged (Hungary). Inst. of Plant Biology; Csanadi, G. [Szeged Univ. (Hungary). Dept. of Biotechnology

    2007-03-15

    Strain AR-46, isolated and identified as Acinetobacter haemolyticus, evolutionally distant from the known hydrocarbon-degrading Acinetobacter spp., proved to have excellent long-chain n-alkane-degrading ability. This is the first detailed report on an n-alkane-utilizing strain belonging to this species. The preferred substrate is n-hexadecane, with an optimal temperature of 37 C under aerobic conditions. Five complete and two partial open reading frames were sequenced and correlated with the early steps of monoterminal oxidation-initiated n-alkane mineralization. The encoded protein sequences and the arrangement of these genes displayed high similarity to those found in Acinetobacter sp. M-1, but AR-46 seemed to have only one alkane hydroxylase gene, with a completely different induction profile. Unique behaviour was also observed in n-alkane bioavailability. Substrate uptake occurred through the hydrophobic surface of n-alkane droplet-adhered cells possessing long, thick fimbriae, which were presumed to play a major role in n-alkane solubilization. A majority of the cells was in detached form, with thick, but short fimbriae. These free cells were permanently hydrophilic, unlike the cells of other Acinetobacter strains. (orig.)

  16. PHENOTYPIC DETECTION OF CARBAPENEM RESISTANCE IN CLINICAL ISOLATES OF ACINETOBACTER BAUMANII IN KANCHIPURAM

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    Sivasankari S

    2014-03-01

    Full Text Available Acinctobacter species are common non fermentative gram negative bacilli isolated in clinical laboratory most frequently encountered species. Acinetobacter resistance is develop due to acquired resistance. Because of frequent multidrug resistance isolates carbapenems have become important for treating resistant strains. There is a need for rapid screening & detection of MBL in Acinetobacter to modify the treatment. The present study was aim to determine the resistance of A.baumanii complese to various classes of drugs and to carbapenems and MBL production. Samples such as urine, blood, sputum, pus & body fluids. All samples were processed as per CLSI guidelines. Meropenem resistant strains were screened for carbapenemase and MBL production. Out of 92 Acinetobacter 85 (92.39% were Acinetobacter baumanii. More than 80% resistance is seen in 3rd generation Cephalosporins. Out of 21 meropenem resistant strains 14 were carbapenemase positive and 3 were MBL producers. Our study shows raising trend of multidrug resistance and carbapenem. This will help in early detection and better treatment modalities.

  17. Cryo-electron tomography analysis of membrane vesicles from Acinetobacter baumannii ATCC19606(T)

    NARCIS (Netherlands)

    Koning, Roman I.; de Breij, Anna; Oostergetel, Gert T.; Nibbering, Peter H.; Koster, Abraham J.; Dijkshoorn, Lenie

    2013-01-01

    Acinetobacter baumannii is an important nosocomial pathogen responsible for colonization and infection of critically ill patients. Its virulence attributes together with the condition of the host determine the pathogenicity of A. baumannii. These virulence factors may be delivered to host cells by m

  18. Towards an explanation for the success of Acinetobacter baumannii in the human host

    NARCIS (Netherlands)

    Breij, Anastasia (Anna)

    2012-01-01

    Acinetobacter baumannii is an important nosocomial pathogen responsible for outbreaks of infection worldwide. The studies presented in this thesis aimed to gain further insight into the bacterial and host factors associated with the pathogenesis of A. baumannii to seek an explanation for the clinica

  19. Mutant Prevention Concentrations of Imipenem and Meropenem against Pseudomonas aeruginosa and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    E. Dahdouh

    2014-01-01

    Full Text Available The aim of this study was to determine the usefulness of the MPC of carbapenems against clinical isolates of Pseudomonas spp. and Acinetobacter spp. and to assess its possible relationship with mechanisms of resistance. Detection of the mechanisms of resistance was performed using Antibiotic Susceptibility Testing, Double Disk Synergy, disk antagonism, addition of NaCl to the medium, addition of PBA or EDTA to Carbapenem disks, addition of PBA to Cefoxitin disks, and CCCP test for 10 Pseudomonas spp. and Acinetobacter baumannii strains. The MIC and MPC were determined using the broth macrodilution and plate dilution methods, respectively. Four Acinetobacter baumannii strains produced MBL. Two of them produced Oxacillinase and one produced ESBL. Two Pseudomonas spp. isolates produced both KPC and MBL. The resistant Acinetobacter spp. and Pseudomonas spp. strains had higher MPC values than susceptible ones. However, the Mutant Selection Window was found to be dependent on the degree of resistance but not on a particular mechanism of resistance. The usefulness of the MPC was found to be dependent on its value. Based on our data, we recommend determining the MPC for each isolate before using it during treatment. Furthermore, the use of T>MSW instead of T>MIC is suggested.

  20. Epidemiology of multiple Acinetobacter outbreaks in The Netherlands during the period 1999-2001

    NARCIS (Netherlands)

    van den Broek, P. J.; Arends, J.; Bernards, A. T.; De Brauwer, E.; Mascini, E. M.; van der Reijden, T. J. K.; Spanjaard, L.; Thewessen, E. A. P. M.; van der Zee, A.; van Zeijl, J. H.; Dijkshoorn, L.

    2006-01-01

    An increase in the number of outbreaks of Acinetobacter infection was notified in The Netherlands during 1999-2001. The present study compared the outbreaks at the species and strain levels, and analysed the epidemiology and control measures at the different locations. For each institute, three repr

  1. Global transcriptome and physiological responses of Acinetobacter oleivorans DR1 exposed to distinct classes of antibiotics.

    Directory of Open Access Journals (Sweden)

    Aram Heo

    Full Text Available The effects of antibiotics on environment-originated nonpathogenic Acinetobacter species have been poorly explored. To understand the antibiotic-resistance mechanisms that function in nonpathogenic Acinetobacter species, we used an RNA-sequencing (RNA-seq technique to perform global gene-expression profiling of soil-borne Acinetobacter oleivorans DR1 after exposing the bacteria to 4 classes of antibiotics (ampicillin, Amp; kanamycin, Km; tetracycline, Tc; norfloxacin, Nor. Interestingly, the well-known two global regulators, the soxR and the rpoE genes are present among 41 commonly upregulated genes under all 4 antibiotic-treatment conditions. We speculate that these common genes are essential for antibiotic resistance in DR1. Treatment with the 4 antibiotics produced diverse physiological and phenotypic changes. Km treatment induced the most dramatic phenotypic changes. Examination of mutation frequency and DNA-repair capability demonstrated the induction of the SOS response in Acinetobacter especially under Nor treatment. Based on the RNA-seq analysis, the glyoxylate-bypass genes of the citrate cycle were specifically upregulated under Amp treatment. We also identified newly recognized non-coding small RNAs of the DR1 strain, which were also confirmed by Northern blot analysis. These results reveal that treatment with antibiotics of distinct classes differentially affected the gene expression and physiology of DR1 cells. This study expands our understanding of the molecular mechanisms of antibiotic-stress response of environment-originated bacteria and provides a basis for future investigations.

  2. Multidrug resistant Acinetobacter baumannii reaches a new frontier: prosthetic hip joint infection.

    Science.gov (United States)

    Hischebeth, G T R; Wimmer, M D; Molitor, E; Seifert, H; Gravius, S; Bekeredjian-Ding, I

    2015-02-01

    Acinetobacter baumannii is an emerging nosocomial pathogen primarily in countries with a high prevalence of multidrug resistance. Here we report the detection of a bla OXA23 carbapenemase-producing A. baumannii strain in a German patient with prosthetic hip joint infection following several hip joint surgeries but no history of foreign travel.

  3. Severe Community-Acquired Bloodstream Infection with Acinetobacter ursingii in Person who Injects Drugs.

    Science.gov (United States)

    Salzer, Helmut J F; Rolling, Thierry; Schmiedel, Stefan; Klupp, Eva-Maria; Lange, Christoph; Seifert, Harald

    2016-01-01

    We report a community-acquired bloodstream infection with Acinteobacter ursingii in an HIV-negative woman who injected drugs. The infection was successfully treated with meropenem. Species identification was performed by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Improved identification of Acinetobacter spp. by using this method will help identify clinical effects of this underdiagnosed pathogen.

  4. Meta-analysis of colistin for the treatment of Acinetobacter baumannii infection.

    Science.gov (United States)

    Chen, Zhijin; Chen, Yu; Fang, Yaogao; Wang, Xiaotian; Chen, Yanqing; Qi, Qingsong; Huang, Fang; Xiao, Xungang

    2015-11-24

    Multidrug resistant among Acinetobacter baumannii infection is associated with a high mortality rate and limits the therapeutic options. The aim of this study was to assess the safety and efficacy of colistin monotherapy vs. other single antibiotic therapy AND colistin-based combination therapy (with other antibiotics) vs. colistin alone for the treatment of Acinetobacter baumannii infection. Online electronic database were searched for studies evaluating colistin with or without other antibiotics in treatment of patients with drug-resistant Acinetobacter baumannii infection. Totally, twelve studies met the inclusion criteria. For colistin-based combination therapy, six articles including 668 patients were included. Our results showed that the overall clinical response did not differ significantly between colistin-based combination therapy and monotherapy (OR = 1.37, 95% CI = 0.86-2.19, P = 0.18). This insignificance was also detected in ICU mortality, length of stay and nephrotoxicity (P > 0.05). However, the colistin-based combination therapy was shown increasing the microbiological response (OR = 2.14, 95% CI = 1.48-3.07, P Acinetobacter baumannii infection.

  5. Colistin-Resistant Acinetobacter baumannii Clinical Strains with Deficient Biofilm Formation

    Science.gov (United States)

    Dafopoulou, Konstantina; Xavier, Basil Britto; Hotterbeekx, An; Janssens, Lore; Lammens, Christine; Dé, Emmanuelle; Goossens, Herman; Tsakris, Athanasios; Malhotra-Kumar, Surbhi

    2015-01-01

    In two pairs of clinical colistin-susceptible/colistin-resistant (Csts/Cstr) Acinetobacter baumannii strains, the Cstr strains showed significantly decreased biofilm formation in static and dynamic assays (P Cstr strain and a frameshift mutation in CarO and the loss of a 47,969-bp element containing multiple genes associated with biofilm production in the other. PMID:26666921

  6. Comparative analysis of fecal microflora of healthy full-term Indian infants born with different methods of delivery (vaginal vs cesarean): Acinetobacter sp. prevalence in vaginally born infants

    Indian Academy of Sciences (India)

    Prashant Kumar Pandey; Pankaj Verma; Himanshu Kumar; Ashish Bavdekar; Milind S Patole; Yogesh S Shouche

    2012-12-01

    In this study fecal microflora of human infants born through vaginal delivery (VB) and through cesarean section (CB) were investigated using culture-independent 16S rDNA cloning and sequencing approach. The results obtained clearly revealed that fecal microbiota of VB infants distinctly differ from those in their counterpart CB infants. The intestinal microbiota of infants delivered by cesarean section appears to be more diverse, in terms of bacteria species, than the microbiota of vaginally delivered infants. The most abundant bacterial species present in VB infants were Acinetobacter sp., Bifidobacterium sp. and Staphylococcus sp. However, CB infant’s fecal microbiota was dominated with Citrobacter sp., Escherichia coli and Clostridium difficile. The intestinal microbiota of cesarean section delivered infants in this study was also characterized by an absence of Bifidobacteria species. An interesting finding of our study was recovery of large number of Acinetobacter sp. consisting of Acinetobacter pittii (former Acinetobacter genomic species 3), Acinetobacter junii and Acinetobacter baumannii in the VB infants clone library. Among these, Acinetobacter baumannii is a known nosocomial pathogen and Acinetobacter pittii (genomic species 3) is recently recognized as clinically important taxa within the Acinetobacter calcoaceticus–Acinetobacter baumannii (ACB) complex. Although none of the infants had shown any sign of clinical symptoms of disease, this observation warrants a closer look.

  7. Susceptibility, phenotypes of resistance, and extended-spectrum β-lactamases in Acinetobacter baumannii strains

    Directory of Open Access Journals (Sweden)

    Elzbieta Tryniszewska

    2012-04-01

    Full Text Available Acinetobacter baumannii plays an increasing role in the pathogenesis of infections in humans. The bacilli are frequently isolated from patients treated in intensive care units. A growing resistance to antibiotics is leading to the emergence of strains that are multidrug-resistant and resistant to all available agents. The objective of this study was to assess susceptibility to antibiotics and to determine the presence and current level of the extended-spectrum β-lactamases (ESBLs and attempt to isolate the Acinetobacter baumannii strain carrying the blaPER gene. A total of 51 strains of A. baumannii identified by phenotypic features were examined. That the strains belonged to the species was confirmed by the presence of the blaOXA-51-like; gene. A broth microdilution method was used for antibacterial susceptibility testing. The occurrence of ESBLs was determined using phenotypic double-disk synergy tests. The PCR technique was used to confirm the presence of the blaPER-1; gene encoding ESBL. The most active antibiotics were meropenem, cefepime and ampicillin/sulbactam, with susceptibility shown by 76.5%, 60.8% and 56.9% of the strains, respectively. The strains exhibited the highest resistance (> 75% to piperacillin, tetracycline, ciprofloxacin and cefotaxime. Phenotypic tests revealed ESBL mechanism of resistance in approximately 20% of Acinetobacter baumannii isolates. However, the PCR technique did not confirm the presence of the blaPER-1; gene in any of the Acinetobacter baumannii strains examined in our hospital. Acinetobacter baumannii strains demonstrate considerable resistance to many groups of antibiotics. Our findings indicate the involvement of enzymes belonging to families other than PER β-lactamase in resistance to β-lactams in A. baumannii.

  8. Acinetobacter apis sp. nov., isolated from the intestinal tract of a honey bee, Apis mellifera.

    Science.gov (United States)

    Kim, Pil Soo; Shin, Na-Ri; Kim, Joon Yong; Yun, Ji-Hyun; Hyun, Dong-Wook; Bae, Jin-Woo

    2014-08-01

    A novel Gram-negative, obligate aerobic, non-motile, and both coccobacillus- and bacillus-shaped bacterium, designated strain HYN18(T), was isolated from the intestinal tract of a honey bee (Apis mellifera). The isolate was oxidase-negative and catalase-positive. Strain HYN18(T) showed optimum growth at 25°C, pH 6-7, and in the presence of 1% (w/v) NaCl in trypticase soy broth medium. The isolate was negative for hydrolyses of starch, casein, gelatin and urea, indole production from tryptone and hemolysis on sheep blood agar. A phylogenetic analysis based on the 16S rRNA gene and rpoB gene sequence showed that strain HYN18(T) was most closely related to Acinetobacter nectaris SAP 763.2(T) and A. boissieri SAP 284.1(T) with 98.3% and 98.1% similarity (16S rRNA gene), respectively, and 84.4% similarity with Acinetobacter nectaris SAP 763.2(T) (rpoB gene). The major cellular fatty acids were summed features 3 (comprising C16:1ω7c /C16:1ω6c ), C12:0 and C16:0. The main isoprenoid quinone was ubiquinone-9 (Q-9). The polar lipids of strain HYN18(T) were phosphatidylethanolamine, three unidentified lipids, an unidentified phospholipid and an unidentified glycolipid. The DNA G+C content was 40.6 mol%. DNA-DNA hybridization experiments indicated less than 33 ± 10% relatedness to the closest phylogenetic species, Acinetobacter nectaris SAP 763.2(T). Thus, the phenotypic, phylogenetic and genotypic analyses indicate that strain HYN18(T) is a novel species within the genus Acinetobacter, for which the name Acinetobacter apis is proposed. The type strain is HYN18(T) (=KACC 16906(T) =JCM 18575(T)).

  9. Acinetobacter variabilis sp. nov. (formerly DNA group 15 sensu Tjernberg & Ursing), isolated from humans and animals.

    Science.gov (United States)

    Krizova, Lenka; McGinnis, Jana; Maixnerova, Martina; Nemec, Matej; Poirel, Laurent; Mingle, Lisa; Sedo, Ondrej; Wolfgang, William; Nemec, Alexandr

    2015-03-01

    We aimed to define the taxonomic status of 16 strains which were phenetically congruent with Acinetobacter DNA group 15 described by Tjernberg & Ursing in 1989. The strains were isolated from a variety of human and animal specimens in geographically distant places over the last three decades. Taxonomic analysis was based on an Acinetobacter-targeted, genus-wide approach that included the comparative sequence analysis of housekeeping, protein-coding genes, whole-cell profiling based on matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), an array of in-house physiological and metabolic tests, and whole-genome comparative analysis. Based on analyses of the rpoB and gyrB genes, the 16 strains formed respective, strongly supported clusters clearly separated from the other species of the genus Acinetobacter. The distinctness of the group at the species level was indicated by average nucleotide identity values of ≤82 % between the whole genome sequences of two of the 16 strains (NIPH 2171(T) and NIPH 899) and those of the known species. In addition, the coherence of the group was also supported by MALDI-TOF MS. All 16 strains were non-haemolytic and non-gelatinase-producing, grown at 41 °C and utilized a rather limited number of carbon sources. Virtually every strain displayed a unique combination of metabolic and physiological features. We conclude that the 16 strains represent a distinct species of the genus Acinetobacter, for which the name Acinetobacter variabilis sp. nov. is proposed to reflect its marked phenotypic heterogeneity. The type strain is NIPH 2171(T) ( = CIP 110486(T) = CCUG 26390(T) = CCM 8555(T)).

  10. Colistin and tigecycline for management of external ventricular device-related ventriculitis due to multidrug-resistant Acinetobacter baumannii

    Science.gov (United States)

    Shrestha, Gentle Sunder; Tamang, Sushil; Paneru, Hem Raj; Shrestha, Pramesh Sunder; Keyal, Niraj; Acharya, Subhash Prasad; Marhatta, Moda Nath; Shilpakar, Sushil

    2016-01-01

    Acinetobacter baumannii is an important cause of nosocomial ventriculitis associated with external ventricular device (EVD). It is frequently multidrug resistant (MDR), carries a poor outcome, and is difficult to treat. We report a case of MDR Acinetobacter ventriculitis treated with intravenous and intraventricular colistin together with intravenous tigecycline. The patient developed nephrotoxicity and poor neurological outcome despite microbiological cure. Careful implementation of bundle of measures to minimize EVD-associated ventriculitis is valuable. PMID:27365967

  11. Identification of Acinetobacter baumannii by detection of the blaOXA-51-like carbapenemase gene intrinsic to this species.

    Science.gov (United States)

    Turton, Jane F; Woodford, Neil; Glover, Judith; Yarde, Susannah; Kaufmann, Mary E; Pitt, Tyrone L

    2006-08-01

    bla(OXA-51-like) was sought in clinical isolates of Acinetobacter species in a multiplex PCR, which also detects bla(OXA-23-like) and class 1 integrase genes. All isolates that gave a band for bla(OXA-51-like) identified as A. baumannii. This gene was detected in each of 141 isolates of A. baumannii but not in those of 22 other Acinetobacter species.

  12. Resistência a β-lactâmicos em Acinetobacter spp isolados de efluente hospitalar no sul do Brasil

    OpenAIRE

    Gusatti, Carolina Souza; Ferreira, Alessandra Einsfeld; Fuentefria,Daiane Bopp; Corção, Gertrudes

    2009-01-01

    Acinetobacter spp é um importante patógeno causador de infecções nosocomiais que acomete pacientes imunocomprometidos e capaz de adquirir resistência a antimicrobianos com facilidade. Os esgotos hospitalares são importantes disseminadores de genes de resistência a antimicrobianos para a microbiota ambiental. Neste contexto, 30 cepas de Acinetobacter spp provenientes de efluente de um hospital em Porto Alegre, RS, foram analisados quanto ao perfil de susceptibilidade a β-lactamases, quino...

  13. Prevalence of Pseudomonas aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with chronic periodontal infection

    Directory of Open Access Journals (Sweden)

    Renata Souto

    2014-06-01

    Full Text Available P. aeruginosa and Acinetobacter spp. are important pathogens associated with late nosocomial pneumonia in hospitalized and institutionalized individuals. The oral cavity may be a major source of these respiratory pathogens, particularly in the presence of poor oral hygiene and periodontal infection. This study investigated the prevalence of P. aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with periodontal disease or health. Samples were obtained from 55 periodontally healthy (PH and 169 chronic periodontitis (CP patients. DNA was obtained from the samples and detection of P. aeruginosa and Acinetobacter spp. was carried out by multiplex and nested PCR. P. aeruginosa and Acinetobacter spp. were detected in 40% and 45% of all samples, respectively. No significant differences in the distribution of these microorganisms between men and women, subgingival biofilm and saliva samples, patients 35 years of age, and smokers and non-smokers were observed regardless periodontal status (p > 0.05. In contrast, the frequencies of P. aeruginosa and Acinetobacter spp. in saliva and biofilm samples were significantly greater in CP than PH patients (p < 0.01. Smokers presenting P. aeruginosa and high frequencies of supragingival plaque were more likely to present CP than PH. P. aeruginosa and Acinetobacter spp. are frequently detected in the oral microbiota of CP. Poor oral hygiene, smoking and the presence of P. aeruginosa are strongly associated with periodontitis.

  14. Prevalence of Pseudomonas aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with chronic periodontal infection.

    Science.gov (United States)

    Souto, Renata; Silva-Boghossian, Carina M; Colombo, Ana Paula Vieira

    2014-01-01

    P. aeruginosa and Acinetobacter spp. are important pathogens associated with late nosocomial pneumonia in hospitalized and institutionalized individuals. The oral cavity may be a major source of these respiratory pathogens, particularly in the presence of poor oral hygiene and periodontal infection. This study investigated the prevalence of P. aeruginosa and Acinetobacter spp. in subgingival biofilm and saliva of subjects with periodontal disease or health. Samples were obtained from 55 periodontally healthy (PH) and 169 chronic periodontitis (CP) patients. DNA was obtained from the samples and detection of P. aeruginosa and Acinetobacter spp. was carried out by multiplex and nested PCR. P. aeruginosa and Acinetobacter spp. were detected in 40% and 45% of all samples, respectively. No significant differences in the distribution of these microorganisms between men and women, subgingival biofilm and saliva samples, patients ≤ 35 and > 35 years of age, and smokers and non-smokers were observed regardless periodontal status (p > 0.05). In contrast, the frequencies of P. aeruginosa and Acinetobacter spp. in saliva and biofilm samples were significantly greater in CP than PH patients (p Acinetobacter spp. are frequently detected in the oral microbiota of CP. Poor oral hygiene, smoking and the presence of P. aeruginosa are strongly associated with periodontitis.

  15. Iron acquisition functions expressed by the human pathogen Acinetobacter baumannii.

    Science.gov (United States)

    Zimbler, Daniel L; Penwell, William F; Gaddy, Jennifer A; Menke, Sharon M; Tomaras, Andrew P; Connerly, Pamela L; Actis, Luis A

    2009-02-01

    Acinetobacter baumannii is a gram-negative bacterium that causes serious infections in compromised patients. More recently, it has emerged as the causative agent of severe infections in military personnel wounded in Iraq and Afghanistan. This pathogen grows under a wide range of conditions including iron-limiting conditions imposed by natural and synthetic iron chelators. Initial studies using the type strain 19606 showed that the iron proficiency of this pathogen depends on the expression of the acinetobactin-mediated iron acquisition system. More recently, we have observed that hemin but not human hemoglobin serves as an iron source when 19606 isogenic derivatives affected in acinetobactin transport and biosynthesis were cultured under iron-limiting conditions. This finding is in agreement with the observation that the genome of the strain 17978 has a gene cluster coding for putative hemin-acquisition functions, which include genes coding for putative hemin utilization functions and a TonBExbBD energy transducing system. This system restored enterobactin biosynthesis in an E. coli ExbBD deficient strain but not when introduced into a TonB mutant. PCR and Southern blot analyses showed that this hemin-utilization gene cluster is also present in the 19606 strain. Analysis of the 17978 genome also showed that this strain harbors genes required for acinetobactin synthesis and transport as well as a gene cluster that could code for additional iron acquisition functions. This hypothesis is in agreement with the fact that the inactivation of the basD acinetobactin biosynthetic gene did not affect the growth of A. baumannii 17978 cells under iron-chelated conditions. Interestingly, this second iron uptake gene cluster is flanked by perfect inverted repeats and includes transposase genes that are expressed transcriptionally. Also interesting is the observation that this additional cluster could not be detected in the type strain 19606, an observation that suggests some

  16. Peritoneal dialysis-related peritonitis with Acinetobacter baumannii: a review of seven cases.

    Science.gov (United States)

    Zhang, Wei; Wu, Yong-Gui; Qi, Xiang-Ming; Dai, Hong; Lu, Wen; Zhao, Min

    2014-05-01

    Peritonitis is still known as an important complication of continuous ambulatory peritoneal dialysis (CAPD). Multi-drug resistant (MDR) Acinetobacter baumannii is an increasing problem worldwide. Moreover, the increasing reports of carbapenem-resistant A. baumannii strains is common. Although peritoneal dialysis-related peritonitis with MDR A. baumannii is rarely reported, infection with this organism always results in serious peritonitis and increases the possibility of dropout or mortality. Here, we present 7 cases of peritonitis caused by A. baumannii species. Among those 7 cases, 2 involved MDR A. baumannii, and 1 involved a carbapenem-resistant strain. All the MDR bacterial infections failed treatment. We also review the literature about Acinetobacter peritonitis and current treatment protocols.

  17. Multidrug-resistant Acinetobacter baumannii ventriculitis: successful treatment with intraventricular colistin.

    Science.gov (United States)

    López-Alvarez, B; Martín-Láez, R; Fariñas, M C; Paternina-Vidal, B; García-Palomo, J D; Vázquez-Barquero, A

    2009-11-01

    Acinetobacter baumannii has emerged as an important nosocomial pathogen that can cause a multitude of severe infections. In neurosurgical patients the usual presentation is ventriculitis associated with external ventricular drainage. Carbapenems have been considered the gold standard for the treatment of Acinetobacter baumannii ventriculitis, but resistant isolates are increasing worldwide, reducing the therapeutic options. In many cases polymyxins are the only possible alternative, but their poor blood-brain barrier penetration could require them to be directly administered intraventricularly and clinical experience with this route is limited. We review the literature concerning intraventricular use of colistin (polymyxin E) for A. baumannii ventriculitis and add three cases successfully treated with this method. Our experience suggests that intraventricular colistin is a potentially effective and safe therapy for the treatment of multidrug-resistant A. baumannii central nervous system infections.

  18. Cloning, Expression, and Purification of Nucleoside Diphosphate Kinase from Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Juhi Sikarwar

    2013-01-01

    Full Text Available Acinetobacter baumannii is a multidrug resistant pathogenic bacteria associated with hospital acquired infections. This bacterium possesses a variety of resistance mechanisms which makes it more difficult to control the bacterium with conventional drugs, and, so far no effective drug treatment is available against it. Nucleoside diphosphate kinase is an important enzyme, which maintains the total nucleotide triphosphate pool inside the cell by the transfer of γ-phosphate from NTPs to NDPs. The role of nucleoside diphosphate kinase (Ndk has also been observed in pathogenesis in other organisms. However, intensive studies are needed to decipher its other putative roles in Acinetobacter baumannii. In the present study, we have successfully cloned the gene encoding Ndk and achieved overexpression in bacterial host BL-21 (DE3. The overexpressed protein is further purified by nickel-nitrilotriacetic acid (Ni-NTA chromatography.

  19. Cloning, Expression, and Purification of Nucleoside Diphosphate Kinase from Acinetobacter baumannii

    Science.gov (United States)

    Sikarwar, Juhi; Kaushik, Sanket; Sinha, Mau; Kaur, Punit; Sharma, Sujata; Singh, Tej P.

    2013-01-01

    Acinetobacter baumannii is a multidrug resistant pathogenic bacteria associated with hospital acquired infections. This bacterium possesses a variety of resistance mechanisms which makes it more difficult to control the bacterium with conventional drugs, and, so far no effective drug treatment is available against it. Nucleoside diphosphate kinase is an important enzyme, which maintains the total nucleotide triphosphate pool inside the cell by the transfer of γ-phosphate from NTPs to NDPs. The role of nucleoside diphosphate kinase (Ndk) has also been observed in pathogenesis in other organisms. However, intensive studies are needed to decipher its other putative roles in Acinetobacter baumannii. In the present study, we have successfully cloned the gene encoding Ndk and achieved overexpression in bacterial host BL-21 (DE3). The overexpressed protein is further purified by nickel-nitrilotriacetic acid (Ni-NTA) chromatography. PMID:23662205

  20. Neglected Fournier’s Gangrene Caused by Acinetobacter baumannii: A Rare Case Report

    Directory of Open Access Journals (Sweden)

    Arif Emre

    2016-01-01

    Full Text Available Fournier’s gangrene, rare but life threatening disease, is characterized by an acute necrotic infection of the scrotum, penis, or perineum. Fournier’s gangrene is a mixed infection caused by both aerobic and anaerobic bacteria. Fournier’s gangrene caused by multidrug resistant Acinetobacter baumannii have been reported rarely. The mainstay of treatment is prompt recognition and a combination of antibiotics with radical debridement. We describe a case of a 56-year-old male patient presenting with neglected Fournier’s gangrene caused by Acinetobacter baumannii. Many treatment modalities including broad-spectrum antibiotics, aggressive debridement, negative pressure wound therapy, diversion colostomy, and partial-thickness skin grafts were applied to save the patient’s life.

  1. Toll-Like Receptor 9 Contributes to Defense against Acinetobacter baumannii Infection.

    Science.gov (United States)

    Noto, Michael J; Boyd, Kelli L; Burns, William J; Varga, Matthew G; Peek, Richard M; Skaar, Eric P

    2015-10-01

    Acinetobacter baumannii is a common nosocomial pathogen capable of causing severe diseases associated with significant morbidity and mortality in impaired hosts. Pattern recognition receptors, such as the Toll-like receptors (TLRs), play a key role in pathogen detection and function to alert the immune system to infection. Here, we examine the role for TLR9 signaling in response to A. baumannii infection. In a murine model of A. baumannii pneumonia, TLR9(-/-) mice exhibit significantly increased bacterial burdens in the lungs, increased extrapulmonary bacterial dissemination, and more severe lung pathology compared with those in wild-type mice. Following systemic A. baumannii infection, TLR9(-/-) mice have significantly increased bacterial burdens in the lungs, as well as decreased proinflammatory cytokine and chemokine production. These results demonstrate that TLR9-mediated pathogen detection is important for host defense against the opportunistic pathogen Acinetobacter baumannii.

  2. Bacteremia due to Acinetobacter ursingii in infants: Reports of two cases.

    Science.gov (United States)

    Yakut, Nurhayat; Kepenekli, Eda Kadayifci; Karaaslan, Ayse; Atici, Serkan; Akkoc, Gulsen; Demir, Sevliya Ocal; Soysal, Ahmet; Bakir, Mustafa

    2016-01-01

    Acinetobacter ursingii is an aerobic, gram-negative, opportunistic microorganism which is rarely isolated among Acinetobacter species. We present two immunocompetent infants who developed bacteremia due to A. ursingii. The first patient is a two -month- old boy who had been hospitalized in pediatric surgery unit for suspected tracheo-esophageal fistula because of recurrent aspiration pneumonia unresponsive to antibiotic therapy. The second patient is a fourteen -month- old boy with prolonged vomiting and diarrhea. A. ursingii was isolated from their blood cultures. They were successfully treated with ampicillin-sulbactam. Although A. ursingii has recently been isolated from a clinical specimen; reports of infection with A. ursingii in children are rare. A. ursingii should be kept in mind as an opportunistic microorganism in children.

  3. Prevalence of antibiotic resistance among Acinetobacter baumannii isolates from Aleppo, Syria.

    Science.gov (United States)

    Hamzeh, Abdul Rezzak; Al Najjar, Mona; Mahfoud, Maysa

    2012-10-01

    This study describes and analyzes Acinetobacter baumannii antibiotic susceptibly profile in Aleppo, Syria, thus providing vital information for guiding treatment of A baumannii infections. Two hundred sixty nonrepetitive A baumannii isolates were studied over 3.5 years. Resistance rates are at the higher end of globally reported levels. Newer cephalosporins and β-lactamase-resistant agents are becoming practically ineffective. Better activity is limited to carbapenems and colistin, which elicited the highest susceptibility levels.

  4. Antibiotic-Resistant Acinetobacter baumannii Increasing Success Remains a Challenge as a Nosocomial Pathogen

    OpenAIRE

    Ana Maria Gonzalez-Villoria; Veronica Valverde-Garduno

    2016-01-01

    Antibiotic-resistant infectious bacteria currently imply a high risk and therefore constitute a strong challenge when treating patients in hospital settings. Characterization of these species and of particular strains is a priority for the establishment of diagnostic tests and preventive procedures. The relevance of Acinetobacter baumannii as a problematic microorganism in inpatient facilities, particularly intensive care units, has increased over time. This review aims to draw attention to (...

  5. Peritoneal Dialysis-Related Peritonitis with Acinetobacter baumannii: A Review of Seven Cases

    OpenAIRE

    Zhang, Wei; Wu, Yong-Gui; Qi, Xiang-Ming; Dai, Hong; Lu, Wen; Zhao, Min

    2014-01-01

    Peritonitis is still known as an important complication of continuous ambulatory peritoneal dialysis (CAPD). Multi-drug resistant (MDR) Acinetobacter baumannii is an increasing problem worldwide. Moreover, the increasing reports of carbapenem-resistant A. baumannii strains is common. Although peritoneal dialysis-related peritonitis with MDR A. baumannii is rarely reported, infection with this organism always results in serious peritonitis and increases the possibility of dropout or mortality....

  6. Relación entre virulencia y resistencia antimicrobiana en Acinetobacter baumannii

    OpenAIRE

    Zuñiga, Andres E; Chávez, Mónica; Gómez, Romel F.; Cristina E Cabrera; Corral, Raúl E; López, Bertha

    2010-01-01

    Acinetobacter baumanni causa frecuentemente infecciones intrahospitalarias y actualmente se ha relacionado con el desarrollo de infecciones severas adquiridas en la comunidad. La capacidad de colonizar diversos hábitats y la versatilidad en su metabolismo ha influido en el incremento del número de infecciones nosocomiales, siendo responsable del desarrollo de enfermedades como: sepsis, neumonías y meningitis. Estas infecciones aparecen en forma de brotes, dominados por clones epidémicos con m...

  7. Carbapenem-resistant Acinetobacter pittii strain harboring blaOXA-72 from Brazil.

    Science.gov (United States)

    Chagas, Thiago Pavoni Gomes; Tavares E Oliveira, Thamirys Rachel; D'Alincourt Carvalho-Assef, Ana Paula; Albano, Rodolpho M; Asensi, Marise Dutra

    2017-02-06

    In this study, we report the isolation of OXA-72-producing Acinetobacter pittii in Brazil. A carbapenem-resistant A. pittii strain was recovered from a hospitalized female patient from Espírito Santo, Southeastern Brazil. PCR screening and DNA sequencing allowed us to identify the presence of blaOXA-72. We observed blaOXA-72 in a ~11kb plasmid and flanked by XerC/XerD-binding sites.

  8. Phylogenetic signal in phenotypic traits related to carbon source assimilation and chemical sensitivity in Acinetobacter species.

    Science.gov (United States)

    Van Assche, Ado; Álvarez-Pérez, Sergio; de Breij, Anna; De Brabanter, Joseph; Willems, Kris A; Dijkshoorn, Lenie; Lievens, Bart

    2017-01-01

    A common belief is that the phylogeny of bacteria may reflect molecular functions and phenotypic characteristics, pointing towards phylogenetic conservatism of traits. Here, we tested this hypothesis for a large set of Acinetobacter strains. Members of the genus Acinetobacter are widespread in nature, demonstrate a high metabolic diversity and are resistant to several environmental stressors. Notably, some species are known to cause opportunistic human infections. A total of 133 strains belonging to 33 species with validly published names, two genomic species and species of an as-yet unknown taxonomic status were analyzed using the GENIII technology of Biolog, which allows high-throughput phenotyping. We estimated the strength and significance of the phylogenetic signal of each trait across phylogenetic reconstructions based on partial RNA polymerase subunit B (rpoB) and core genome sequences. Secondly, we tested whether phylogenetic distance was a good predictor of trait differentiation by Mantel test analysis. And finally, evolutionary model fitting was used to determine if the data for each phenotypic character was consistent with a phylogenetic or an essentially random model of trait distribution. Our data revealed that some key phenotypic traits related to substrate assimilation and chemical sensitivity are linked to the phylogenetic placement of Acinetobacter species. The strongest phylogenetic signals found were for utilization of different carbon sources such as some organic acids, amino acids and sugars, thus suggesting that in the diversification of Acinetobacter carbon source assimilation has had a relevant role. Future work should be aimed to clarify how such traits have shaped the remarkable ability of this bacterial group to dominate in a wide variety of habitats.

  9. Metabolism of spacecraft cleaning reagents by Mars Odyssey and Phoenix-associated Acinetobacter

    Science.gov (United States)

    Mogul, Rakesh; Barding, Gregory; Baki, Ryan; Perkins, Nicole; Lee, Sooji; Lalla, Sid; Campos, Alexa; Sripong, Kimberly; Madrid, Steve

    2016-07-01

    The metabolomic and proteomic properties that promote microbial survival in spacecraft assembly facilities are important aspects to planetary protection and astrobiology. In this presentation, we will provide molecular and biological evidence that the spacecraft-associated Acinetobacter metabolize/degrade spacecraft cleaning reagents such as ethanol, 2-propanol, and Kleenol-30. Gas chromatography-mass spectrometry (GC-MS) studies on A. radioresistens 50v1 (Mars Odyssey) show that the metabolome is dependent upon growth conditions and that ^{13}C-labeled ethanol is incorporated into metabolites such as TCA/glyoxylate cycle intermediates, amino acids, monosaccharides, and disaccharides (e.g., trehalose). In fact, plate count assays show that ethanol is a sole carbon source under minimal conditions for several Mars Phoenix and Odyssey-associated Acinetobacter strains, which may explain why the Acinetobacter are among the most abundant genera found in spacecraft assembly facilities. Biochemical analyses support the enzymatic oxidation of ethanol and 2-propanol by a membrane-bound and NAD+/PQQ-dependent alcohol dehydrogenase, with current kinetic data providing similar apparent K _{M} and maximum growth rate values of ˜5 and 8 mM ethanol, respectively. Preliminary GC-MS analysis also suggests that Kleenol-30 is degraded by A. radioresistens 50v1 when grown in ethanol mixtures. Under minimal conditions, A. radioresistens 50v1 (˜10 ^{8} cfu/mL) also displays a remarkable oxidative extremotolerance (˜2-log reduction in 10 mM hydrogen peroxide), which suggests crucial roles for metabolites associated with oxidative stress (e.g., trehalose) and the observed appreciable catalase specific activities. In conclusion, these results provide key insights into the survival strategies of spacecraft-associated Acinetobacter and emphasize the importance of characterizing the carbon metabolism of forward contaminants.

  10. Transformation of Acinetobacter sp. strain BD413 by transgenic sugar beet DNA.

    Science.gov (United States)

    Gebhard, F; Smalla, K

    1998-04-01

    The ability of Acinetobacter sp. strain BD413(pFG4 delta nptII) to take up and integrate transgenic plant DNA based on homologous recombination was studied under optimized laboratory conditions. Restoration of nptII, resulting in kanamycin-resistant transformants, was observed with plasmid DNA, plant DNA, and homogenates carrying the gene nptII. Molecular analysis showed that some transformants not only restored the 317-bp deletion but also obtained additional DNA.

  11. Genomic and functional analysis of the type VI secretion system in Acinetobacter.

    Science.gov (United States)

    Weber, Brent S; Miyata, Sarah T; Iwashkiw, Jeremy A; Mortensen, Brittany L; Skaar, Eric P; Pukatzki, Stefan; Feldman, Mario F

    2013-01-01

    The genus Acinetobacter is comprised of a diverse group of species, several of which have raised interest due to potential applications in bioremediation and agricultural purposes. In this work, we show that many species within the genus Acinetobacter possess the genetic requirements to assemble a functional type VI secretion system (T6SS). This secretion system is widespread among Gram negative bacteria, and can be used for toxicity against other bacteria and eukaryotic cells. The most studied species within this genus is A. baumannii, an emerging nosocomial pathogen that has become a significant threat to healthcare systems worldwide. The ability of A. baumannii to develop multidrug resistance has severely reduced treatment options, and strains resistant to most clinically useful antibiotics are frequently being isolated. Despite the widespread dissemination of A. baumannii, little is known about the virulence factors this bacterium utilizes to cause infection. We determined that the T6SS is conserved and syntenic among A. baumannii strains, although expression and secretion of the hallmark protein Hcp varies between strains, and is dependent on TssM, a known structural protein required for T6SS function. Unlike other bacteria, A. baumannii ATCC 17978 does not appear to use its T6SS to kill Escherichia coli or other Acinetobacter species. Deletion of tssM does not affect virulence in several infection models, including mice, and did not alter biofilm formation. These results suggest that the T6SS fulfils an important but as-yet-unidentified role in the various lifestyles of the Acinetobacter spp.

  12. Genomic and functional analysis of the type VI secretion system in Acinetobacter.

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    Brent S Weber

    Full Text Available The genus Acinetobacter is comprised of a diverse group of species, several of which have raised interest due to potential applications in bioremediation and agricultural purposes. In this work, we show that many species within the genus Acinetobacter possess the genetic requirements to assemble a functional type VI secretion system (T6SS. This secretion system is widespread among Gram negative bacteria, and can be used for toxicity against other bacteria and eukaryotic cells. The most studied species within this genus is A. baumannii, an emerging nosocomial pathogen that has become a significant threat to healthcare systems worldwide. The ability of A. baumannii to develop multidrug resistance has severely reduced treatment options, and strains resistant to most clinically useful antibiotics are frequently being isolated. Despite the widespread dissemination of A. baumannii, little is known about the virulence factors this bacterium utilizes to cause infection. We determined that the T6SS is conserved and syntenic among A. baumannii strains, although expression and secretion of the hallmark protein Hcp varies between strains, and is dependent on TssM, a known structural protein required for T6SS function. Unlike other bacteria, A. baumannii ATCC 17978 does not appear to use its T6SS to kill Escherichia coli or other Acinetobacter species. Deletion of tssM does not affect virulence in several infection models, including mice, and did not alter biofilm formation. These results suggest that the T6SS fulfils an important but as-yet-unidentified role in the various lifestyles of the Acinetobacter spp.

  13. Antimicrobial Resistance of Acinetobacter baumannii to Imipenem in Iran: A Systematic Review and Meta-Analysis

    OpenAIRE

    Pourhajibagher, Maryam; Hashemi, Farhad B.; POURAKBARI, Babak; Aziemzadeh, Masoud; Bahador, Abbas

    2016-01-01

    Imipenem-resistant multi-drug resistant (IR-MDR) Acinetobacter baumannii has been emerged as a morbidity successful nosocomial pathogen throughout the world.To address imipenem being yet the most effective antimicrobial agent against A. baumannii to control outbreaks and treat patients, a systematic review and meta-analysis was performed to evaluate the prevalence of IR-MDR A. baumannii. We systematically searched Web of Science, PubMed, MEDLINE, Science Direct, EMBASE, Scopus, Cochrane Libra...

  14. [The review of carbapenem resistance in clinical isolates of Acinetobacter baumannii].

    Science.gov (United States)

    Goić-Barisić, Ivana; Tonkić, Marija

    2009-10-01

    Increasing reports of Acinetobacter infections that cause pneumonia, meningitis, endocarditis, and bacteriaemia underline the clinical importance of this pathogen. Members of the genus Acinetobacter, particularly Acinetobacter baumannii, are now recognized as significant nosocomial pathogens, particularly for the subset of critically-ill patients requiring mechanical ventilation in hospital intensive care units. A. baumannii has itself a quite high level of naturally-occurring antibiotic resistance. The organism can survive for long periods in the hospital environment including dry and humid areas. One of the most worrying antibiotic resistance problems in A. baumannii is the increasing trend of carbapenem resistance, present also in few Croatian hospitals. Infections caused by this Gram-negative bacillus are common in the intensive care units anticipated by colonized patients. The increasing trend of carbapenem resistance in A. baumannii could be mediated from metallo-beta-lactamases (VIM, IMP, and SIM), carbapenem-hydrolyzing oxacillinases (OXA), porin modifications for influx of carbapenems (33-kDa CarO protein) and/or often combined mechanisms of resistance. The investigation of the background of carbapenem resistance in relevant clinical isolates of A. baumannii from Split University Hospital confirmed present of carbapenem-hydrolyzing oxacillinases OXA-107 representing a more recent evolutionary adaptation OXA-51-like enzyme to antibiotic challenge with carbapenems.

  15. Molecular Typing of Acinetobacter Baumannii Clinical Strains in Tehran by Pulsed-Field Gel Electrophoresis

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    Neda Farahani

    2013-03-01

    Full Text Available Background & Objective : Currently, Acinetobacter baumannii is an important nosocomial pathogen insofar as its hospital outbreaks have been described from various geographical areas. Since the discrimination of strains within a species is important for delineating nosocomial outbreaks, this study was conducted with the aim of genotyping the A. baumannii clinical strains in Tehran via the pulsed-field gel electrophoresis (PFGE method, which is the most accurate method used for the typing of bacterial species.   Materials & methods: This study was performed on 70 isolates of acinetobacter baumannii isolated from patients from Baqiyatallah, Rasoole Akram, and Milad hospitals in Tehran. Cultural and biochemical methods were used for the identification of the isolates in species level, and then susceptibility tests were carried out on 50 isolates of A. baumannii using the disk diffusion method. The PFGE method was performed on the isolates by Apa I restriction enzyme. Finally, the results of the PFGE were analyzed. Result: Acinetobacter baumannii strains isolated from hospitals in Tehran showed seven different genetic patterns, two of which were sporadic . Also, genotypic profiles were different in each hospital, and different patterns of genetic resistance to common antibiotics were observed. Conclusion: A lthough diversity was observed among the strains of A. baumannii by the PFGE method in Tehran, no epidemic strains were found among them.  

  16. Salt adaptation in Acinetobacter baylyi: identification and characterization of a secondary glycine betaine transporter.

    Science.gov (United States)

    Sand, Miriam; de Berardinis, Veronique; Mingote, Ana; Santos, Helena; Göttig, Stephan; Müller, Volker; Averhoff, Beate

    2011-10-01

    Members of the genus Acinetobacter are well known for their metabolic versatility that allows them to adapt to different ecological niches. Here, we have addressed how the model strain Acinetobacter baylyi copes with different salinities and low water activities. A. baylyi tolerates up to 900 mM sodium salts and even higher concentrations of potassium chloride. Growth at high salinities was better in complex than in mineral medium and addition of glycine betaine stimulated growth at high salinities in mineral medium. Cells grown at high salinities took up glycine betaine from the medium. Uptake of glycine betaine was energy dependent and dependent on a salinity gradient across the membrane. Inspection of the genome sequence revealed two potential candidates for glycine betaine transport, both encoding potential secondary transporters, one of the major facilitator superfamily (MFS) class (ACIAD2280) and one of the betaine/choline/carnitine transporter (BCCT) family (ACIAD3460). The latter is essential for glycine betaine transport in A. baylyi. The broad distribution of ACIAD3460 homologues indicates the essential role of secondary transporters in the adaptation of Acinetobacter species to osmotic stress.

  17. Mechanisms of resistance to carbapenems in meropenem- resistant Acinetobacter isolates from clinical samples

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    Sinha M

    2007-01-01

    Full Text Available Purpose: To analyze the resistance mechanisms in Acinetobacter species by phenotypic methods. Methods: Antibiotic susceptibility profile for 150 clinical isolates of Acinetobacte r was determined by the standard disk diffusion method. Isolates detected to be meropenem resistant were tested further by broth microdilution minimum inhibitory concentration (MIC for meropenem. The resistant isolates were also tested for metallo β -lactamase (MBL production by the double-disk approximation test, for AmpC beta-lactamase production and efflux pump detection by agar microdilution MIC with and without reserpine. Results: Twenty-one isolates were found resistant to meropenem by the standard disk diffusion method. Nine samples were from patients admitted in intensive care units (ICUs. Broth microdilution MICs of the isolates revealed low-level resistance to meropenem. MBL was not produced by any of these isolates. AmpC β -lactamases were produced by nine (43% isolates. ′Efflux pump′-mediated resistance to meropenem was detected in two out of nine random isolates tested for the same . Conclusions: Carbapenem resistance is not uncommon in Acinetobacter isolates. AmpC production may cause carbapenem resistance. MBL and efflux pump may not be important causes of carbapenem resistance.

  18. Biodegradation of phenol by free and immobilized Acinetobacter sp.strain PD12

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; TIAN Ye; HAN Bin; ZHAO Hua-bing; BI Jian-nan; CAI Bao-li

    2007-01-01

    A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD 12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol (PVA) was used as a gel matrix to immobilize Acinetobacter sp. strain PD12 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4℃ for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD 12 possesses a good application potential in the treatment of phenol-containing wastewater.

  19. Characterization and molecular epidemiology of extensively prevalent nosocomial isolates of drug-resistant Acinetobacter spp.

    Science.gov (United States)

    Carvalho, A A; Cardoso, L L; Nogueira, H S; Menezes, E V; Xavier, M A S; Barreto, N A P; Fernandes, L F; Xavier, A R E O

    2016-08-19

    Acinetobacter sp isolates deserve special attention once they have emerged globally in healthcare institutions because they display numerous intrinsic and acquired drug-resistance mechanisms. This study assessed the antibiotic susceptibility profile, the presence of the genetic marker blaOXA-23, and the clonal relationship among 34 nosocomial isolates of Acinetobacter spp obtained at a hospital in southeastern Brazil. Antibiotic sensitivity analysis was performed by the standard disc-diffusion method. All isolates were found to be extensively resistant to several drugs, but sensitive to polymyxin B. A polymerase chain reaction (PCR) assay was used to detect the blaOXA-23 gene, which is associated with carbapenem resistance. The genetic profile and the clonal relationship among isolates were analyzed via enterobacterial repetitive intergenic consensus (ERIC)-PCR. The Acinetobacter spp were divided into four groups with 22 distinct genetic subgroups. ERIC-PCR analysis revealed the genetic diversity among isolates, which, despite having a heterogeneous profile, displayed 100% clonality among 56% (19/34) of them.

  20. Characterization of Patients with Acinetobacter baumannii Ventilator-associated Pneumonia in Progressive Care Units

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    Leonardo Maikel Gómez Carcassés

    2016-08-01

    Full Text Available Background: Acinetobacter baumannii has become one of the most important nosocomial pathogens. Objective: to characterize the patients diagnosed with ventilator-associated pneumonia due to Acinetobacter baumannii in the Progressive Care Units. Methods: a case series study of patients diagnosed with ventilator-associated pneumonia due to Acinetobacter baumannii was conducted in the Progressive Care Units of the Dr. Gustavo Aldereguía Lima Hospital of Cienfuegos from December 2013 through December 2014. The study variables included: age, sex, comorbid conditions, cause of admission, duration of ventilation, length of stay, antibiotic used, and status at discharge. Results: a total of 39 patients were studied, which accounted for 69.2% of the patients in Progressive Care Units. The mean age was 55.7 years. Males predominated. Sixty four point two percent of patients reported one or more past illnesses. Most admissions to emergency services were due to clinical reasons (51.3%. Sixty nine point two percent of patients received mechanical ventilation for 3 to 21 days. The average stay was 14.7 days. Seventy one point eight percent received a combined antimicrobial treatment and most of them were discharged alive (64.1%. Overall mortality was 35.9%. Conclusions: there was a predominance of males, patients over 60 years of age and clinical cases. The study patients needed mechanical ventilation for a medium length of time and combined antimicrobial treatment. Most patients were discharged alive, and mortality was within the range of that reported in the scientific literature.

  1. Molecular epidemiology of Acinetobacter baumannii in central intensive care unit in Kosova teaching hospital

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    Lul Raka

    2009-12-01

    Full Text Available Infections caused by bacteria of genus Acinetobacter pose a significant health care challenge worldwide. Information on molecular epidemiological investigation of outbreaks caused by Acinetobacter species in Kosova is lacking. The present investigation was carried out to enlight molecular epidemiology of Acinetobacterbaumannii in the Central Intensive Care Unit (CICU of a University hospital in Kosova using pulse field gel electrophoresis (PFGE. During March - July 2006, A. baumannii was isolated from 30 patients, of whom 22 were infected and 8 were colonised. Twenty patients had ventilator-associated pneumonia, one patient had meningitis, and two had coinfection with bloodstream infection and surgical site infection. The most common diagnoses upon admission to the ICU were politrauma and cerebral hemorrhage. Bacterial isolates were most frequently recovered from endotracheal aspirate (86.7%. First isolation occurred, on average, on day 8 following admission (range 1-26 days. Genotype analysis of A. baumannii isolates identified nine distinct PFGE patterns, with predominance of PFGE clone E represented by isolates from 9 patients. Eight strains were resistant to carbapenems. The genetic relatedness of Acinetobacter baumannii was high, indicating cross-transmission within the ICU setting. These results emphasize the need for measures to prevent nosocomial transmission of A. baumannii in ICU.

  2. Signature motifs identify an Acinetobacter Cif virulence factor with epoxide hydrolase activity.

    Science.gov (United States)

    Bahl, Christopher D; Hvorecny, Kelli L; Bridges, Andrew A; Ballok, Alicia E; Bomberger, Jennifer M; Cady, Kyle C; O'Toole, George A; Madden, Dean R

    2014-03-14

    Endocytic recycling of the cystic fibrosis transmembrane conductance regulator (CFTR) is blocked by the CFTR inhibitory factor (Cif). Originally discovered in Pseudomonas aeruginosa, Cif is a secreted epoxide hydrolase that is transcriptionally regulated by CifR, an epoxide-sensitive repressor. In this report, we investigate a homologous protein found in strains of the emerging nosocomial pathogens Acinetobacter nosocomialis and Acinetobacter baumannii ("aCif"). Like Cif, aCif is an epoxide hydrolase that carries an N-terminal secretion signal and can be purified from culture supernatants. When applied directly to polarized airway epithelial cells, mature aCif triggers a reduction in CFTR abundance at the apical membrane. Biochemical and crystallographic studies reveal a dimeric assembly with a stereochemically conserved active site, confirming our motif-based identification of candidate Cif-like pathogenic EH sequences. Furthermore, cif expression is transcriptionally repressed by a CifR homolog ("aCifR") and is induced in the presence of epoxides. Overall, this Acinetobacter protein recapitulates the essential attributes of the Pseudomonas Cif system and thus may facilitate airway colonization in nosocomial lung infections.

  3. Identification, genotypic relation, and clinical features of colistin-resistant isolates of Acinetobacter genomic species 13BJ/14TU from bloodstreams of patients in a university hospital.

    Science.gov (United States)

    Lee, Seung Yeob; Shin, Jong Hee; Park, Kyung Hwa; Kim, Ju Hee; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook; Kim, Soo Hyun

    2014-03-01

    Colistin resistance remains rare among clinical isolates of Acinetobacter species. We noted the emergence of colistin-resistant bloodstream isolates of the Acinetobacter genomic species (GS) 13BJ/14TU from patients at a university hospital between 2003 and 2011. We report here, for the first time, the microbiological and molecular characteristics of these isolates, with clinical features of Acinetobacter GS 13BJ/14TU bacteremia. All 11 available patient isolates were correctly identified as Acinetobacter GS 13BJ/14TU using partial rpoB gene sequencing but were misidentified using the phenotypic methods Vitek 2 (mostly as Acinetobacter baumannii), MicroScan (mostly as A. baumannii/Acinetobacter haemolyticus), and the API 20 NE system (all as A. haemolyticus). Most isolates were susceptible to commonly used antibiotics, including carbapenems, but all were resistant to colistin, for which it is unknown whether the resistance is acquired or intrinsic. However, the fact that none of the patients had a history of colistin therapy strongly suggests that Acinetobacter GS 13BJ/14TU is innately resistant to colistin. The phylogenetic tree of multilocus sequence typing (MLST) showed that all 11 isolates formed a separate cluster from other Acinetobacter species and yielded five sequence types. However, pulsed-field gel electrophoresis (PFGE) revealed 11 distinct patterns, suggesting that the bacteremia had occurred sporadically. Four patients showed persistent bacteremia (6 to 17 days), and all 11 patients had excellent outcomes with cleared bacteremia, suggesting that patients with Acinetobacter GS 13BJ/14TU-associated bacteremia show a favorable outcome. These results emphasize the importance of precise species identification, especially regarding colistin resistance in Acinetobacter species. In addition, MLST offers another approach to the identification of Acinetobacter GS 13BJ/14TU, whereas PFGE is useful for genotyping for this species.

  4. Origin in Acinetobacter guillouiae and dissemination of the aminoglycoside-modifying enzyme Aph(3')-VI.

    Science.gov (United States)

    Yoon, Eun-Jeong; Goussard, Sylvie; Touchon, Marie; Krizova, Lenka; Cerqueira, Gustavo; Murphy, Cheryl; Lambert, Thierry; Grillot-Courvalin, Catherine; Nemec, Alexandr; Courvalin, Patrice

    2014-10-21

    The amikacin resistance gene aphA6 was first detected in the nosocomial pathogen Acinetobacter baumannii and subsequently in other genera. Analysis of 133 whole-genome sequences covering the taxonomic diversity of Acinetobacter spp. detected aphA6 in the chromosome of 2 isolates of A. guillouiae, which is an environmental species, 1 of 8 A. parvus isolates, and 5 of 34 A. baumannii isolates. The gene was also present in 29 out of 36 A. guillouiae isolates screened by PCR, indicating that it is ancestral to this species. The Pnative promoter for aphA6 in A. guillouiae and A. parvus was replaced in A. baumannii by PaphA6, which was generated by use of the insertion sequence ISAba125, which brought a -35 sequence. Study of promoter strength in Escherichia coli and A. baumannii indicated that PaphA6 was four times more potent than Pnative. There was a good correlation between aminoglycoside MICs and aphA6 transcription in A. guillouiae isolates that remained susceptible to amikacin. The marked topology differences of the phylogenetic trees of aphA6 and of the hosts strongly support its recent direct transfer within Acinetobacter spp. and also to evolutionarily remote bacterial genera. Concomitant expression of aphA6 must have occurred because, contrary to the donors, it can confer resistance to the new hosts. Mobilization and expression of aphA6 via composite transposons and the upstream IS-generating hybrid PaphA6, followed by conjugation, seems the most plausible mechanism. This is in agreement with the observation that, in the recipients, aphA6 is carried by conjugative plasmids and flanked by IS that are common in Acinetobacter spp. Our data indicate that resistance genes can also be found in susceptible environmental bacteria. Importance: We speculated that the aphA6 gene for an enzyme that confers resistance to amikacin, the most active aminoglycoside for the treatment of nosocomial infections due to Acinetobacter spp., originated in this genus before

  5. Antibiogram Pattern of Acinetobacter Isolated from Clinical Samples at Tehran’s Araad Hospital (2009-2011

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    Kobra Eslami

    2014-03-01

    Full Text Available Absrtact Background and objective: Acinetobacter is common in nosocomial pathogen and it is a health care associated opportunistic multidrug resistant pathogen. The purpose of this study is to determine the sensivity and resistance of Acinetobacter strains that was isolated from clinical samples of patients who was admitted to Arad hospital in Tehran. Materials and methods: In this descriptive examination, after extracting Acinetobacter derivations from clinical samples (Urine, sond fuli, sputum, wound, blood and bronchial, Their sensitivity was measured using standard Kirby-Bauer test, in contract with following antibiotics Amikacin, Ciprofloxacin, Gentamicin, Imipenem, Ceftriaxone Sulfametoxazole Trimetoprime, Piperacilin and Cefotaxime and then the results analayzed. Results: In this study of 225 samples of Acinetobacter derivation isolated from clinical specimens, the most amount of sensivity was Piperacilin and Ciprofloxacin and the most amount of resistance was to Gentamicin and Amikacin. Conclusion: The results of this study are indicating that Acinetobacter strains resistance has increased against Gentamycin and Amikacin; presumably due to excessive consumption of these antibiotics. It is obvious that, with increasing consumption of antibiotics, and consequently, augmentation of antibacterial resistance, control of this resistance factor is necessary and inevitable, we recommended to avoid unnecessary usage of antibiotics.

  6. Distribution of carbapenem resistance determinants among epidemic and non-epidemic types of Acinetobacter species in Japan.

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    Matsui, Mari; Suzuki, Satowa; Yamane, Kunikazu; Suzuki, Masato; Konda, Toshifumi; Arakawa, Yoshichika; Shibayama, Keigo

    2014-06-01

    We performed a comparative molecular analysis on three types of clinically isolated Acinetobacter spp.: epidemic sequence types (STs) of Acinetobacter baumannii (epidemic ST-AB), non-epidemic sequence types of A. baumannii (non-epidemic ST-AB) and non-baumannii Acinetobacter spp. A total of 87 isolates - 46 A. baumannii, 25 A. pittii and 16 A. nosocomialis - from 43 hospitals were analysed. Of these, 31 A. baumannii isolates were ST1 or ST2 according to the Pasteur Institute multilocus sequence typing scheme and were defined as epidemic ST-AB. The other 15 A. baumannii isolates were defined as non-epidemic ST-AB. The epidemic ST-AB isolates harboured the blaOXA-23-like gene or had an ISAba1 element upstream of blaOXA-51-like, or both, whereas non-epidemic ST-AB and non-baumannii Acinetobacter spp. isolates harboured blaOXA-58-like or metallo-β-lactamase genes, or both. The proportion of multidrug-resistant isolates was significantly higher in the epidemic ST-AB isolates (48 %) than that in the other types of Acinetobacter isolates (5 %) (PAcinetobacter spp. isolates than with epidemic ST-AB isolates, regardless of bacterial species. In addition, this study revealed that, even in Japan, where IMP-type metallo-β-lactamase producers are endemic, epidemic ST-AB harbouring blaIMP have not yet emerged.

  7. Comparison of Disk Diffusion and E-Test Methods for Doripenem Susceptibility of Nosocomial Acinetobacter Baumannii Strains

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    Yesim Cekin

    2014-03-01

    Full Text Available Aim: Acinetobacter species are amoung the most common two cause of infections isolated from patients of intensive care unit in our hospital. Doripenem which acts by inhibiting cell wall synthesis is resently introduced for use in our country is broad spectrum antibiotic belonging to carbapenems. There are many studies investigating the susceptibility of doripenem of Acinetobacter baumannii which is isolated as a cause of ventilatory associated pneumonia in the literature. We aimed to compare e-test and disc diffusion methods for doripenem susceptibility of acinetobacter baumannii strains as nosocomial infections Acinetobacter baumanni isolates detected as nosocomial infection. Material and Method:. Between January to December, 2009 a total of 94 Acinetobacter baumanni strains isolated from different clinical specimens from intensive care units have been studied for doripenem susceptibility by disc diffusion and E-test methods. Minimal inhibitory consantrations (MIC were accepted as; sensitive %u22641 %u03BCg/ml, intermadiate 2-4 %u03BCg/ml, resistant >4 %u03BCg/ml and diameters of inhibition zone with 10 µg disc; sensitive

  8. Drug-resistant gene based genotyping for Acinetobacter baumannii in tracing epidemiological events and for clinical treatment within nosocomial settings

    Institute of Scientific and Technical Information of China (English)

    JIN Hui; XU Xiao-min; MI Zu-huang; MOU Yi; LIU Pei

    2009-01-01

    Background Acinetobacter baumannfi has emerged as an important pathogen related to serious infections and nosocomial outbreaks around the world. However, of the frequently used methods, pulsed-field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) in Acinetobacter baumannii genotyping lack the direct molecular proof of drug resistance. This study was conducted to establish a typing method based on drug resistant gene identification in contrast to traditional PFGE and AFLP in the period of nosocomial epidemic or outbreak.Methods From January 2005 to October 2005, twenty-seven strains of Acinetobacter species from Intensive Care Units, the Second Affiliated Hospital in Ningbo were isolated, including both epidemic and sporadic events. Susceptibility test, PFGE, AFLP and drug resistance gene typing (DRGT) were carded out to confirm the drug resistance and analyze the genotyping, respectively. PFGE was used as a reference to evaluate the typeability of DRGT and AFLP.Results Twenty-seven strains of Acinetobacter displayed multiple antibiotic resistance and drug resistant genes, and β-lactamase genes were detected in 85.2% strains. The result of DRGT was comparable to PFGE in Acinetobacter strains with different drug resistance though a little difference existed, and even suggested a molecular evolution course of different drug-resistant strains. AFLP showed great polymorphism between strains and had weak ability in distinguishing the drug resistance.Conclusion Compared to AFLP and PFGE, DRGT is useful to analyze localized molecular epidemiology of nosocomial infections and outbreaks, which would benefit clinical diagnosis and therapy.

  9. Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for species identification of Acinetobacter strains isolated from blood cultures.

    Science.gov (United States)

    Kishii, K; Kikuchi, K; Matsuda, N; Yoshida, A; Okuzumi, K; Uetera, Y; Yasuhara, H; Moriya, K

    2014-05-01

    The clinical relevance of Acinetobacter species, other than A. baumannii, as human pathogens has not been sufficiently assessed owing to the insufficiency of simple phenotypic clinical diagnostic laboratory tests. Infections caused by these organisms have different impacts on clinical outcome and require different treatment and management approaches. It is therefore important to correctly identify Acinetobacter species. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been introduced to identify a wide range of microorganisms in clinical laboratories, but only a few studies have examined its utility for identifying Acinetobacter species, particularly those of the non-Acinetobacter baumannii complex. We therefore evaluated MALDI-TOF MS for identification of Acinetobacter species by comparing it with sequence analysis of rpoB using 123 isolates of Acinetobacter species from blood. Of the isolates examined, we identified 106/123 (86.2%) to species, and 16/123 (13.0%) could only be identified as acinetobacters. The identity of one isolate could not be established. Of the 106 species identified, 89/106 (84.0%) were confirmed by rpoB sequence analysis, and 17/106 (16.0%) were discordant. These data indicate correct identification of 89/123 (72.4%) isolates. Surprisingly, all blood culture isolates were identified as 13 species of Acinetobacter, and the incidence of Acinetobacter pittii was unexpectedly high (42/123; 34.1%) and exceeded that of A. baumannii (22/123; 17.9%). Although the present identification rate using MALDI-TOF MS is not acceptable for species-level identification of Acinetobacter, further expansion of the database should remedy this situation.

  10. Control of an Outbreak of Acinetobacter baumannii in Burn Unit in a Tertiary Care Hospital of North India

    Directory of Open Access Journals (Sweden)

    Shweta Sharma

    2014-01-01

    Full Text Available Acinetobacter infection is increasing in hospitals and now it is considered as a global threat, as it can be easily transmitted and remain viable in the hospital environment for a long time due to its multidrug-resistant status, resistance to desiccation, and tendency to adhere to inanimate surfaces. Outbreaks caused by multidrug-resistant Acinetobacter baumannii (MDRAB are difficult to control and have substantial morbidity and mortality, especially in vulnerable host. Here we are describing an outbreak of multidrug-resistant Acinetobacter baumannii in burn unit of a tertiary care hospital in India followed by its investigation and infection control measures taken to curtail the outbreak. Outbreak investigation and environmental sampling are the key factors which help in deciding the infection control strategies for control of outbreak. Implementation of contact precautions, hand hygiene, personnel protective equipment, environmental disinfection, isolation of patients, and training of health care workers are effective measures to control the outbreak of MDRAB in burn unit.

  11. [Influence of poly-β-1-6-N-acetylglucosamine on biofilm formation and drug resistance of Acinetobacter baumannii].

    Science.gov (United States)

    Guo, Haina; Xiang, Jun

    2015-02-01

    Acinetobacter baumannii has emerged as one of the leading bacteria for nosocomial infections, especially in burn wards and ICUs. The bacteria can easily form biofilm and readily attach to abiotic and biotic surfaces, resulting in persistent biofilm-mediated infections. Being surrounded by self-produced extracellular polymeric substance (EPS), the microorganisms in biofilm can acquire protective property against detrimental environment and their tolerance toward antibiotics is increased. Poly-β-1-6-N-acetylglucosamine (PNAG), the common constituent of EPS in Acinetobacter baumannii, acts as the key virulence factor and plays a crucial role in biofilm formation process. This review describes the properties and functions of the PNAG and its influence on biofilm formation and drug resistance of Acinetobacter baumannii.

  12. Characterization of a Pseudomonas putida rough variant evolved in a mixed species biofilm with Acinetobacter sp. strain C6

    DEFF Research Database (Denmark)

    Hansen, Susse Kirkelund; Haagensen, Janus Anders Juul; Gjermansen, Morten

    2007-01-01

    biosynthesis. Here we investigate further the biofilm physiology and the phenotypic characteristics of the selected P. putida rough colony variants. The coexistence of the P. putida population in a mixed-species biofilm with Acinetobacter sp. strain C6 is dependent on the benzoate excreted from Acinetobacter...... was shown to evolve rapidly by natural selection of better-adapted variants in a mixed-species biofilm consortium (S. K. Hansen, P. B. Rainey, J. A. Haagensen, and S. Molin, Nature 445:533-536, 2007). Adaptation was caused by mutations in a wapH homolog (PP4943) involved in core lipopolysaccharide...... during the catabolism of benzyl alcohol, the sole carbon source. Examination of biofilm development and the dynamics of the wild-type consortium revealed that the biofilm environment became oxygen limited, possibly with low oxygen concentrations around Acinetobacter microcolonies. In contrast to P...

  13. Antimicrobial effects of Ferula gummosa Boiss gum against extended-spectrum β-lactamase producing Acinetobacter clinical isolates

    Science.gov (United States)

    Afshar, Fatemeh Farid; Saffarian, Parvaneh; Hosseini, Hamideh Mahmoodzadeh; Sattarian, Fereshteh; Amin, Mohsen; Fooladi, Abbas Ali Imani

    2016-01-01

    Background and Objectives: Acinetobacter spp. are important causes of nosocomial infections. They possess various antibiotic resistance mechanisms including extended spectrum beta lactamases (ESBLs). The aim of this study was to determine antibiotic resistance profile of Acinetobacter clinical isolates especially among ESBL-producing strains and to investigate the antimicrobial effects of oleo-gum-resin extract and essential oil of Ferula gummosa Boiss. Materials and Methods: 120 Acinetobacter strains were isolated from various clinical samples of hospitalized patients in Baqiyatallah hospital, Tehran during 2011–2012. Antibiotic susceptibility test was performed on the isolates using disk diffusion method. To detect and confirm the ESBL-positive isolates, phenotypic and genotypic tests were performed. Three types of F. gummosa oleo-gum-resin extracts and essential oils were prepared and the bioactive components of F. gummosa Boiss extracts were determined by GC-Mass chromatography. F. gummosa antimicrobial activity was evaluated against standard strain of Acinetobacter baumannii (ATCC19606) as well as Acinetobacter clinical isolates using well and disk diffusion methods. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution method. Results: 46 isolates were resistant to all tested antibiotics. All clinical isolates were resistant to cefotaxime. 12.94% of the isolates were phenotypically ESBL-producing among which 94.2% carried ESBL genes ( bla PER-1 , bla OXA-4 and bla CTX-M ) detected by PCR. Oleo-gum-resin of F. gummosa had significant antibacterial activity and alcoholic essential oil had higher inhibitory effect on Acinetobacter strains (MIC of 18.75 mg/ml). Conclusion: Ferula gummosa extract contained components with well-known antimicrobial effects.

  14. Effect of Acinetobacter sp on metalaxyl degradation and metabolite profile of potato seedlings (Solanum tuberosum L. alpha variety.

    Directory of Open Access Journals (Sweden)

    Fabiola G Zuno-Floriano

    Full Text Available One of the most serious diseases in potato cultivars is caused by the pathogen Phytophthora infestans, which affects leaves, stems and tubers. Metalaxyl is a fungicide that protects potato plants from Phytophthora infestans. In Mexico, farmers apply metalaxyl 35 times during the cycle of potato production and the last application is typically 15 days before harvest. There are no records related to the presence of metalaxyl in potato tubers in Mexico. In the present study, we evaluated the effect of Acinetobacter sp on metalaxyl degradation in potato seedlings. The effect of bacteria and metalaxyl on the growth of potato seedlings was also evaluated. A metabolite profile analysis was conducted to determine potential molecular biomarkers produced by potato seedlings in the presence of Acinetobacter sp and metalaxyl. Metalaxyl did not affect the growth of potato seedlings. However, Acinetobacter sp strongly affected the growth of inoculated seedlings, as confirmed by plant length and plant fresh weights which were lower in inoculated potato seedlings (40% and 27%, respectively compared to the controls. Acinetobacter sp also affected root formation. Inoculated potato seedlings showed a decrease in root formation compared to the controls. LC-MS/MS analysis of metalaxyl residues in potato seedlings suggests that Acinetobacter sp did not degrade metalaxyl. GC-TOF-MS platform was used in metabolic profiling studies. Statistical data analysis and metabolic pathway analysis allowed suggesting the alteration of metabolic pathways by both Acinetobacter sp infection and metalaxyl treatment. Several hundred metabolites were detected, 137 metabolites were identified and 15 metabolic markers were suggested based on statistical change significance found with PLS-DA analysis. These results are important for better understanding the interactions of putative endophytic bacteria and pesticides on plants and their possible effects on plant metabolism.

  15. Effect of Acinetobacter sp on Metalaxyl Degradation and Metabolite Profile of Potato Seedlings (Solanum tuberosum L.) Alpha Variety

    Science.gov (United States)

    Zuno-Floriano, Fabiola G.; Miller, Marion G.; Aldana-Madrid, Maria L.; Hengel, Matt J.; Gaikwad, Nilesh W.; Tolstikov, Vladimir; Contreras-Cortés, Ana G.

    2012-01-01

    One of the most serious diseases in potato cultivars is caused by the pathogen Phytophthora infestans, which affects leaves, stems and tubers. Metalaxyl is a fungicide that protects potato plants from Phytophthora infestans. In Mexico, farmers apply metalaxyl 35 times during the cycle of potato production and the last application is typically 15 days before harvest. There are no records related to the presence of metalaxyl in potato tubers in Mexico. In the present study, we evaluated the effect of Acinetobacter sp on metalaxyl degradation in potato seedlings. The effect of bacteria and metalaxyl on the growth of potato seedlings was also evaluated. A metabolite profile analysis was conducted to determine potential molecular biomarkers produced by potato seedlings in the presence of Acinetobacter sp and metalaxyl. Metalaxyl did not affect the growth of potato seedlings. However, Acinetobacter sp strongly affected the growth of inoculated seedlings, as confirmed by plant length and plant fresh weights which were lower in inoculated potato seedlings (40% and 27%, respectively) compared to the controls. Acinetobacter sp also affected root formation. Inoculated potato seedlings showed a decrease in root formation compared to the controls. LC-MS/MS analysis of metalaxyl residues in potato seedlings suggests that Acinetobacter sp did not degrade metalaxyl. GC–TOF–MS platform was used in metabolic profiling studies. Statistical data analysis and metabolic pathway analysis allowed suggesting the alteration of metabolic pathways by both Acinetobacter sp infection and metalaxyl treatment. Several hundred metabolites were detected, 137 metabolites were identified and 15 metabolic markers were suggested based on statistical change significance found with PLS-DA analysis. These results are important for better understanding the interactions of putative endophytic bacteria and pesticides on plants and their possible effects on plant metabolism. PMID:22363586

  16. Characterizing in vivo pharmacodynamics of carbapenems against Acinetobacter baumannii in a murine thigh infection model to support breakpoint determinations.

    Science.gov (United States)

    Macvane, Shawn H; Crandon, Jared L; Nicolau, David P

    2014-01-01

    Pharmacodynamic profiling data of carbapenems for Acinetobacter spp. are sparse. This study aimed to determine the pharmacodynamic targets of carbapenems for Acinetobacter baumannii based on a range of percentages of the dosing interval in which free drug concentrations remained above the MIC (fT>MIC) in the neutropenic murine thigh infection model. fT>MIC values of 23.7%, 32.8%, and 47.5% resulted in stasis, 1-log reductions, and 2-log reductions in bacterial density after 24 h, respectively. The pharmacodynamic targets of carbapenems for A. baumannii demonstrated in vivo are similar to those of other Gram-negative bacteria.

  17. Whole-Genome Sequence of a Colombian Acinetobacter baumannii Strain, a Coproducer of OXA-72 and OXA-255-Like Carbapenemases

    Science.gov (United States)

    Saavedra, Sandra Yamile; Prada-Cardozo, Diego; Pérez-Cardona, Hermes; Hidalgo, Andrea Melissa; González, María Nilse; Reguero, María T.; Valenzuela de Silva, Emilia M.; Mantilla, José R.; Falquet, Laurent; Barreto-Hernández, Emiliano; Duarte, Carolina

    2017-01-01

    ABSTRACT Colombian Acinetobacter baumannii strain ST920 was isolated from the sputum of a 68-year-old male patient. This isolate possessed blaOXA-72 and blaOXA-255-like genes. The assembled genome contained 4,104,098 pb and 38.79% G+C content. This is the first case reported of the coproduction (blaOXA-72 and blaOXA-255-like) of carbapenem-hydrolyzing class D β-lactamases (CHDLs) in Acinetobacter baumannii. PMID:28209815

  18. Productive degradation of the biocide benzylbenzoate by Acinetobacter sp. strain AG1 isolated from the River Elbe.

    Science.gov (United States)

    Göttsching, Anja; Schmidt, Stefan

    2007-04-01

    From water sampled in the River Elbe, we isolated a bacterial strain able to use the biocidal compound benzylbenzoate as its sole source of carbon and energy under aerobic conditions. This isolate was tentatively assigned to the genus Acinetobacter due to its morphological, physiological and partial SSU rRNA gene sequence properties. The productive bacterial degradation of the biocide benzylbenzoate was demonstrated, and the catabolic sequence was elucidated biochemically. Growth experiments, along with enzymatic studies, demonstrated that strain Acinetobacter sp. AG1 hydrolyzed benzylbenzoate enzymatically to yield benzylalcohol and benzoate. Benzylalcohol was further transformed to benzoate via benzaldehyde. Benzoate was subsequently channeled via catechol into the oxoadipate pathway for further degradation.

  19. Characterization of hydrogen peroxide-resistant Acinetobacter species isolated during the Mars Phoenix spacecraft assembly.

    Science.gov (United States)

    Derecho, I; McCoy, K B; Vaishampayan, P; Venkateswaran, K; Mogul, R

    2014-10-01

    The microbiological inventory of spacecraft and the associated assembly facility surfaces represent the primary pool of forward contaminants that may impact the integrity of life-detection missions. Herein, we report on the characterization of several strains of hydrogen peroxide-resistant Acinetobacter, which were isolated during the Mars Phoenix lander assembly. All Phoenix-associated Acinetobacter strains possessed very high catalase specific activities, and the specific strain, A. gyllenbergii 2P01AA, displayed a survival against hydrogen peroxide (no loss in 100 mM H2O2 for 1 h) that is perhaps the highest known among Gram-negative and non-spore-forming bacteria. Proteomic characterizations reveal a survival mechanism inclusive of proteins coupled to peroxide degradation (catalase and alkyl hydroperoxide reductase), energy/redox management (dihydrolipoamide dehydrogenase), protein synthesis/folding (EF-G, EF-Ts, peptidyl-tRNA hydrolase, DnaK), membrane functions (OmpA-like protein and ABC transporter-related protein), and nucleotide metabolism (HIT family hydrolase). Together, these survivability and biochemical parameters support the hypothesis that oxidative tolerance and the related biochemical features are the measurable phenotypes or outcomes for microbial survival in the spacecraft assembly facilities, where the low-humidity (desiccation) and clean (low-nutrient) conditions may serve as selective pressures. Hence, the spacecraft-associated Acinetobacter, due to the conferred oxidative tolerances, may ultimately hinder efforts to reduce spacecraft bioburden when using chemical sterilants, thus suggesting that non-spore-forming bacteria may need to be included in the bioburden accounting for future life-detection missions.

  20. Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem.

    Science.gov (United States)

    Minerdi, Daniela; Zgrablic, Ivan; Castrignanò, Silvia; Catucci, Gianluca; Medana, Claudio; Terlizzi, Maria Elena; Gribaudo, Giorgio; Gilardi, Gianfranco; Sadeghi, Sheila J

    2015-10-12

    Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance.

  1. Combination therapy in severe Acinetobacter baumannii infections: an update on the evidence to date.

    Science.gov (United States)

    Durante-Mangoni, Emanuele; Utili, Riccardo; Zarrilli, Raffaele

    2014-01-01

    Acinetobacter baumannii is a drug-resistant Gram-negative pathogen increasingly causing hospital-acquired infections in critically ill patients. In this review, we summarize the current mechanisms of antimicrobial resistance in A. baumannii and describe in detail recent in vitro and in vivo experimental data on the activity of antimicrobial combinations against this microorganism. We then introduce the rationale for the use of combination antibiotic therapy in resistant A. baumannii infections. Finally, we present and critically discuss both uncontrolled clinical studies and the few randomized clinical trials of combination antimicrobial therapy for these infections, with a special focus on ongoing multinational trials and optimal approach to future research in this field.

  2. Antibioterapia de largo espectro como factor de risco para o isolamento de acinetobacter baumanni multiresistente

    OpenAIRE

    2014-01-01

    Antibioterapia de largo espectro é reconhecida como um factor de risco para a infecções multiresistentes. O objectivo é avaliar a associaçao entre antibioterapia de largo espectro com Meropenem (MP) e Piperacilina/Tazobactam (PT) com o isolamento de Acinetobacter baumanni multiresistente (ABMR). Estudo caso-controlo retrospectivo. Incluidos os individuos com ABMR+ no nosso hospital em 2010. Calculamos a incidenca nos Serviços Cirúrgicos, Serviços Médicos e Unidades de Cuidados Intensi...

  3. Explorando el plegamiento metallo-beta-lactamasa en el genoma de Acinetobacter baumanni

    OpenAIRE

    Rodriguez-Calviño, Fabiola

    2012-01-01

    Acinetobacter baumannii fue considerado siempre como un patógeno de relativa baja virulencia, pero durante las dos últimas décadas, este microorganismo oportunista ha emergido como uno de los mayores problemas encarados por el sistema clínico en hospitales de todo el mundo. Como consecuencia inevitable de la presión selectiva impuesta por el uso abusivo de antibióticos en el tratamiento de infecciones, se han descrito cepas clínicas multirresistentes de A. baumannii, con una alta capacidad...

  4. Sepsis por Acinetobacter baumannii multirresistente: a propósito de un caso

    OpenAIRE

    Hernández Blanco, Javier Enrique; Arrieta Aguilera, Ana Milena; Arcón Medina, Dewitt Fabián; Castellano Orcasita, Juan Enrique

    2012-01-01

    En este artículo se revisa el caso clínico de un paciente con cuadro de infección nosocomial por Acinetobacter baumannii multirresistente, quien a pesar del tratamiento instaurado presentó deterioro de su condición clínica. Se realiza una revisión bibliográfica en diversas bases de datos con el fin de mencionar actualizaciones en el tema y describir el mecanismo de acción antibiótica y resistencia bacteriana que ha dificultado en los últimos años el manejo de estos pacientes. http://revist...

  5. Caracterización de integrones de clase I en aislamientos hospitalarios de acinetobacter baumannii

    OpenAIRE

    Gáfaro Montejo, Alexis

    2012-01-01

    Se analizaron 129 aislamientos de Acinetobacter baumannii obtenidos de hospitales colombianos de tercer nivel con el objetivo de detectar y caracterizar integrones de tipo I (elementos genéticos importantes por la capacidad de adquirir determinantes genéticos de resistencia a los antibióticos) y su relación con el fenotipo de resistencia antibiótica. De los aislamientos estudiados el 24% fueron positivos para la presencia del integrón de tipo I. La caracterización de estos últimos demostró...

  6. In Vivo Fitness Adaptations of Colistin-Resistant Acinetobacter baumannii Isolates to Oxidative Stress

    Science.gov (United States)

    Singh, Shweta S.; Alamneh, Yonas; Casella, Leila G.; Ernst, Robert K.; Lesho, Emil P.; Waterman, Paige E.; Zurawski, Daniel V.

    2016-01-01

    ABSTRACT The loss of fitness in colistin-resistant (CR) Acinetobacter baumannii was investigated using longitudinal isolates from the same patient. Early CR isolates were outcompeted by late CR isolates for growth in broth and survival in the lungs of mice. Fitness loss was associated with an increased susceptibility to oxidative stress since early CR strains had reduced in vitro survival in the presence of hydrogen peroxide and decreased catalase activity compared to that of late CR and colistin-susceptible (CS) strains. PMID:27993849

  7. Antibiotic Resistance and Carriage Integron Classes in Clinical Isolates of Acinetobacter Baumannii from Isfahan Hospitals, Iran

    Directory of Open Access Journals (Sweden)

    Fahimeh Nourbakhsh

    2017-01-01

    Full Text Available Background Acinetobacter baumannii is a significant nosocomial pathogen around the world, especially in the intensive care unit that most A. baumannii infections are caused by the outbreak strains. Objectives This study has been performed in Acinetobacter baumannii isolates, aimed to detect integron classes I, II, III and molecular typing of A. baumannii genes. Methods In this Cross-sectional study, Acinetobacter baumannii isolated from 150 patients in Isfahan hospitals then antibiotic resistance pattern was determined by disk diffusion method (Kirby Bauer. The presence of genes coding in antibiotic resistance and integrons class I, II, III were analyzed by using of M-PCR method. The data were analyzed by Chi-square, Fischer’s test and SPSS statistical software version 16. Results Antibiotic resistance pattern for Acinetobacter baumannii show that the high resistance was for ciprofloxacin with frequency of 98.3%, ceftazidime with 89.4%, and tetracycline with frequency of 87.3%. The most sensitive antibiotics were chloramphenicol, and nitrofurantoin with frequency of 3.5% and 3.2% resistance. The detection of dfrA1 (63.7%, sul1 (68.6%, aac (3-IV (54.4%, tet (B (22.4%, tet (A (78.3%, aadA1 (15.4%, CITM (17. %, vim (12.2%, Qnr (17.1%, blaSHV (19.8%, sim (7.8%, Oxa-24-like (13.2%, Oxa-51-like (11.9%, Oxa-58-like (39.4%, Oxa-23-like (12.6%, imp (9.2%, cmlA (19% and cat1 (8.6% were respectively reported too. Also in this study Frequency of integrons class 1, 2, 3 were (100%, (28%, (6.6% respectively. Conclusions High prevalence of integrons among Acinetobater baumannii isolated from Isfahan hospitals indicate the importance role of integron classes in multidrug resistance. Considering the increasing pattern of MDR infections is one of the important issues of treatment which can be effective strategy for curing.

  8. Clonal spread of blaOXA-72-carrying Acinetobacter baumannii sequence type 512 in Taiwan.

    Science.gov (United States)

    Kuo, Han-Yueh; Hsu, Po-Jui; Chen, Jiann-Yuan; Liao, Po-Cheng; Lu, Chia-Wei; Chen, Chang-Hua; Liou, Ming-Li

    2016-07-01

    This is the first report to show an insidious outbreak of armA- and blaOXA-72-carrying Acinetobacter baumannii sequence type 512 (ST512) at a study hospital in northern Taiwan. Multilocus sequence typing revealed that this was a ST512 clone. All of the isolates with ST512 carried a novel 12,056-bp repGR2 in combination with a repGR12-type plasmid. This plasmid, designated pAB-ML, had one copy of the blaOXA-72 gene that was flanked by XerC/XerD-like sites and conferred resistance to carbapenems.

  9. Carbapenem-resistance and pathogenicity of bovine Acinetobacter indicus-like isolates

    Science.gov (United States)

    Leidner, Ursula; Semmler, Torsten; Scheufen, Sandra; Ewers, Christa

    2017-01-01

    The objective of this study was to characterize blaOXA-23 harbouring Acinetobacter indicus-like strains from cattle including genomic and phylogenetic analyses, antimicrobial susceptibility testing and evaluation of pathogenicity in vitro and in vivo. Nasal and rectal swabs (n = 45) from cattle in Germany were screened for carbapenem-non-susceptible Acinetobacter spp. Thereby, two carbapenem resistant Acinetobacter spp. from the nasal cavities of two calves could be isolated. MALDI-TOF mass spectrometry and 16S rDNA sequencing identified these isolates as A. indicus-like. A phylogenetic tree based on partial rpoB sequences indicated closest relation of the two bovine isolates to the A. indicus type strain A648T and human clinical A. indicus isolates, while whole genome comparison revealed considerable intraspecies diversity. High mimimum inhibitory concentrations were observed for carbapenems and other antibiotics including fluoroquinolones and gentamicin. Whole genome sequencing and PCR mapping revealed that both isolates harboured blaOXA-23 localized on the chromosome and surrounded by interrupted Tn2008 transposon structures. Since the pathogenic potential of A. indicus is unknown, pathogenicity was assessed employing the Galleria (G.) mellonella infection model and an in vitro cytotoxicity assay using A549 human lung epithelial cells. Pathogenicity in vivo (G. mellonella killing assay) and in vitro (cytotoxicity assay) of the two A. indicus-like isolates was lower compared to A. baumannii ATCC 17978 and similar to A. lwoffii ATCC 15309. The reduced pathogenicity of A. indicus compared to A. baumannii correlated with the absence of important virulence genes encoding like phospholipase C1+C2, acinetobactin outer membrane protein BauA, RND-type efflux system proteins AdeRS and AdeAB or the trimeric autotransporter adhesin Ata. The emergence of carbapenem-resistant A. indicus-like strains from cattle carrying blaOXA-23 on transposable elements and revealing genetic

  10. The effect of terminal cleaning on environmental contamination rates of multidrug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Strassle, Paula; Thom, Kerri A; Johnson, J Kristie; Johnsonm, J Kristie; Leekha, Surbhi; Lissauer, Matthew; Zhu, Jingkun; Harris, Anthony D

    2012-12-01

    We evaluated the prevalence of multidrug-resistant Acinetobacter baumannii environmental contamination before and after discharge cleaning in rooms of infected/colonized patients. 46.9% of rooms and 15.3% of sites were found contaminated precleaning, and 25% of rooms and 5.5% of sites were found contaminated postcleaning. Cleaning significantly decreased environmental contamination of A baumannii; however, persistent contamination represents a significant risk factor for transmission. Further studies on this and more effective cleaning methods are needed.

  11. Genomic fingerprinting Acinetobacter baumannii: amplification of multiple inter-repetitive extragenic palindromic sequences.

    Science.gov (United States)

    Sheehan, C; Lynch, M; Cullen, C; Cryan, B; Greer, P; Fanning, S

    1995-09-01

    Acinetobacter species are important nosocomial pathogens. A rapid and sensitive identification system, capable of providing strain identity at the genetic level, is required to identify outbreak strains and facilitate the early implementation of infection control procedures. Repetitive extragenic palindromic (REP) elements, have been identified in numerous bacteria and these genomic sequences provide useful targets for DNA amplification. A method for amplifying inter-REP DNA sequences, REP-multiple arbitrary amplicon profiling (REP-MAAP), is described and applied to 29 Acinetobacter baumannii from clinical samples. Amplified polymorphic DNA patterns were demonstrated for all isolates and those displaying identical REP-MAAP patterns were considered identical at the genetic level. In the spring of 1993, 10 intensive care unit patients had endotracheal colonization with A. baumannii (five with REP-MAAP I and five with REP-MAAP II patterns). These findings suggested nosocomial transmission of organisms which was terminated by standard infection control measures. No further A. baumannii were detected until the winter of 1993 when isolates of different REP-MAAP groups emerged, suggesting that factors other than nosocomial transmission were implicated.

  12. Antibiotic-Resistant Acinetobacter baumannii Increasing Success Remains a Challenge as a Nosocomial Pathogen

    Directory of Open Access Journals (Sweden)

    Ana Maria Gonzalez-Villoria

    2016-01-01

    Full Text Available Antibiotic-resistant infectious bacteria currently imply a high risk and therefore constitute a strong challenge when treating patients in hospital settings. Characterization of these species and of particular strains is a priority for the establishment of diagnostic tests and preventive procedures. The relevance of Acinetobacter baumannii as a problematic microorganism in inpatient facilities, particularly intensive care units, has increased over time. This review aims to draw attention to (i the historical emergence of carbapenem-resistant Acinetobacter baumannii, (ii the current status of surveillance needs in Latin America, and (iii recent data suggesting that A. baumannii continues to spread and evolve in hospital settings. First, we present synopsis of the series of events leading to the discovery and precise identification of this microorganism in hospital settings. Then key events in the acquisition of antibiotic-resistant genes by this microorganism are summarized, highlighting the race between new antibiotic generation and emergence of A. baumannii resistant strains. Here we review the historical development of this species as an infectious threat, the current state of its distribution, and antibiotic resistance characteristics, and we discuss future prospects for its control.

  13. Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain.

    Science.gov (United States)

    Li, Hong; Ai, Hainan; Kang, Li; Sun, Xingfu; He, Qiang

    2016-11-01

    Measures for removal of toxic harmful algal blooms often cause lysis of algal cells and release of microcystins (MCs). In this study, Acinetobacter sp. CMDB-2 that exhibits distinct algal lysing activity and MCs degradation capability was isolated. The physiological response and morphological characteristics of toxin-producing Microcystis aeruginosa, the dynamics of intra- and extracellular MC-LR concentration were studied in an algal/bacterial cocultured system. The results demonstrated that Acinetobacter sp. CMDB-2 caused thorough decomposition of algal cells and impairment of photosynthesis within 24 h. Enhanced algal lysis and MC-LR release appeared with increasing bacterial density from 1 × 10(3) to 1 × 10(7) cells/mL; however, the MC-LR was reduced by nearly 94% within 14 h irrespective of bacterial density. Measurement of extracellular and intracellular MC-LR revealed that the toxin was decreased by 92% in bacterial cell incubated systems relative to control and bacterial cell-free filtrate systems. The results confirmed that the bacterial metabolite caused 92% lysis of Microcystis aeruginosa cells, whereas the bacterial cells were responsible for approximately 91% reduction of MC-LR. The joint efforts of the bacterium and its metabolite accomplished the sustainable removal of algae and MC-LR. This is the first report of a single bacterial strain that achieves these dual actions.

  14. Silver Nanocomposite Biosynthesis: Antibacterial Activity against Multidrug-Resistant Strains of Pseudomonas aeruginosa and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Klebson Silva Santos

    2016-09-01

    Full Text Available Bacterial resistance is an emerging public health issue that is disseminated worldwide. Silver nanocomposite can be an alternative strategy to avoid Gram-positive and Gram-negative bacteria growth, including multidrug-resistant strains. In the present study a silver nanocomposite was synthesized, using a new green chemistry process, by the addition of silver nitrate (1.10−3 mol·L−1 into a fermentative medium of Xanthomonas spp. to produce a xanthan gum polymer. Transmission electron microscopy (TEM was used to evaluate the shape and size of the silver nanoparticles obtained. The silver ions in the nanocomposite were quantified by flame atomic absorption spectrometry (FAAS. The antibacterial activity of the nanomaterial against Escherichia coli (ATCC 22652, Enterococcus faecalis (ATCC 29282, Pseudomonas aeruginosa (ATCC 27853 and Staphylococcus aureus (ATCC 25923 was carried out using 500 mg of silver nanocomposite. Pseudomonas aeruginosa and Acinetobacter baumannii multidrug-resistant strains, isolated from hospitalized patients were also included in the study. The biosynthesized silver nanocomposite showed spherical nanoparticles with sizes smaller than 10 nm; 1 g of nanocomposite contained 49.24 µg of silver. Multidrug-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii, and the other Gram-positive and Gram-negative bacteria tested, were sensitive to the silver nanocomposite (10–12.9 mm of inhibition zone. The biosynthesized silver nanocomposite seems to be a promising antibacterial agent for different applications, namely biomedical devices or topical wound coatings.

  15. The opportunistic human pathogen Acinetobacter baumannii senses and responds to light.

    Science.gov (United States)

    Mussi, María A; Gaddy, Jennifer A; Cabruja, Matías; Arivett, Brock A; Viale, Alejandro M; Rasia, Rodolfo; Actis, Luis A

    2010-12-01

    Light is a ubiquitous environmental signal that many organisms sense and respond to by modulating their physiological responses accordingly. While this is an expected response among phototrophic microorganisms, the ability of chemotrophic prokaryotes to sense and react to light has become a puzzling and novel issue in bacterial physiology, particularly among bacterial pathogens. In this work, we show that the opportunistic pathogen Acinetobacter baumannii senses and responds to blue light. Motility and formation of biofilms and pellicles were observed only when bacterial cells were incubated in darkness. In contrast, the killing of Candida albicans filaments was enhanced when they were cocultured with bacteria under light. These bacterial responses depend on the expression of the A. baumannii ATCC 17978 A1S_2225 gene, which codes for an 18.6-kDa protein that contains an N-terminal blue-light-sensing-using flavin (BLUF) domain and lacks a detectable output domain(s). Spectral analyses of the purified recombinant protein showed its ability to sense light by a red shift upon illumination. Therefore, the A1S_2225 gene, which is present in several members of the Acinetobacter genus, was named blue-light-sensing A (blsA). Interestingly, temperature plays a role in the ability of A. baumannii to sense and respond to light via the BlsA photoreceptor protein.

  16. Heterotrophic nitrogen removal by Acinetobacter sp. Y1 isolated from coke plant wastewater.

    Science.gov (United States)

    Liu, YuXiang; Hu, Tingting; Song, Yujie; Chen, Hongping; Lv, YongKang

    2015-11-01

    A strain of Acinetobacter sp. Y1, which exhibited an amazing ability to remove ammonium, nitrite and nitrate, was isolated from the activated sludge of a coking wastewater treatment plant. The aim of this work was to study the ability, influence factors and possible pathway of nitrogen removal by Acinetobacter sp. Y1. Results showed that maximum removal rate of NH4(+)-N by the strain was 10.28 mg-N/L/h. Carbon source had significant influence on the growth and ammonium removal efficiencies of strain Y1. Pyruvate, citrate and acetate were favourable carbon sources for the strain. Temperature, pH value and shaking speed could affect the growth and nitrogen removal ability. Nitrate or nitrite could be used as a sole nitrogen source for the growth and removed efficiently by the strain. N2 levels increased to 53.74%, 50.21% and 55.13% within 36 h when 100 mg/L NH4(+)-N, NO2(-)-N or NO3(-) -N was used as sole nitrogen source in the gas detection experiment. The activities of hydroxylamine oxidoreductase (HAO), nitrate reductase (NR) and nitrite reductase (NiR), which are key enzymes in heterotrophic nitrification and aerobic denitrification, were all detectable in the strain. Consequently, a possible pathway for ammonium removal by the strain was also suggested.

  17. Improved Triacylglycerol Production in Acinetobacter baylyi ADP1 by Metabolic Engineering

    Directory of Open Access Journals (Sweden)

    Karp Matti

    2011-05-01

    Full Text Available Abstract Background Triacylglycerols are used in various purposes including food applications, cosmetics, oleochemicals and biofuels. Currently the main sources for triacylglycerol are vegetable oils, and microbial triacylglycerol has been suggested as an alternative for these. Due to the low production rates and yields of microbial processes, the role of metabolic engineering has become more significant. As a robust model organism for genetic and metabolic studies, and for the natural capability to produce triacylglycerol, Acinetobacter baylyi ADP1 serves as an excellent organism for modelling the effects of metabolic engineering for energy molecule biosynthesis. Results Beneficial gene deletions regarding triacylglycerol production were screened by computational means exploiting the metabolic model of ADP1. Four deletions, acr1, poxB, dgkA, and a triacylglycerol lipase were chosen to be studied experimentally both separately and concurrently by constructing a knock-out strain (MT with three of the deletions. Improvements in triacylglycerol production were observed: the strain MT produced 5.6 fold more triacylglycerol (mg/g cell dry weight compared to the wild type strain, and the proportion of triacylglycerol in total lipids was increased by 8-fold. Conclusions In silico predictions of beneficial gene deletions were verified experimentally. The chosen single and multiple gene deletions affected beneficially the natural triacylglycerol metabolism of A. baylyi ADP1. This study demonstrates the importance of single gene deletions in triacylglycerol metabolism, and proposes Acinetobacter sp. ADP1 as a model system for bioenergetic studies regarding metabolic engineering.

  18. Biodegradation of phenol by using free and immobilized cells of Acinetobacter sp. BS8Y.

    Science.gov (United States)

    Jiang, Lichun; Ruan, Qiping; Li, Rulan; Li, Tiandong

    2013-03-01

    Strain BS8Y with high biodegradation activity and high tolerance of phenol was isolated from activated sludge in an insulating material plant of China. This strain was capable of removing 99.2% of the initial 600 mg/l phenol in liquid minimal medium within 24 h and tolerating phenol at concentrations of up to 1,200 mg/ml. DNA sequencing and homologous analysis of the 16S rRNA gene identified that the strain BS8Y belonged to an Acinetobacter species. Polyvinyl alcohol was used as gel matrix to immobilize the strain BS8Y. The factors affecting the phenol degradation by immobilized cells and the phenol removal efficiency of free and immobilized cells were investigated; the stability of the immobilized cells is also reported. The results show that the immobilized cells could tolerate a higher phenol level and protected the bacteria much more effectively against changes in temperature and pH. The phenol degradation efficiency was high at up to 96% within 30 h, with an initial concentration of 800 mg/l phenol, and the immobilized cells showed better performance than the suspended cells. Reusability tests revealed that the immobilized cells were stable enough even after reuse for ten times or storing at 4°C for 35 d. These results demonstrate that immobilized Acinetobacter sp. BS8Y possesses a good application potential in the treatment of phenol-containing wastewater.

  19. Risk factors and outcomes of imipenem-resistant Acinetobacter bloodstream infection in North-eastern Malaysia

    Institute of Scientific and Technical Information of China (English)

    Zakuan Zainy Deris; Mohd Nazri Shafei; Azian Harun

    2011-01-01

    Objective: To determine the risk factors and outcomes of imipenem-resistant Acinetobacterbaumannii (IRAB) bloodstream infection (BSI) cases, since there is very little publication on Acinetobacter baumannii infections from Malaysia. Methods: A cross sectional study of 41 cases (73.2%) of imipenem-sensitive Acinetobacter baumanii (ISAB) and 15 cases (26.8%) of IRAB was conducted in a teaching hospital which was located at North-Eastern state of Malaysia. Results:There was no independent risk factor for IRAB BSI identified but IRAB BSI was significantly associated with longer bacteraemic days [OR 1.23 (95% CI 1.01, 1.50)]. Although prior use of carbepenems and cephalosporin were higher among IRAB than ISAB group, statistically they were not significant. There was no significant difference in term of outcomes between the two groups. Conclusions: Although statistically not significant, this analysis compliments previous publication highlighting the importance of appropriate empiric antibiotic usage in hospital especially carbepenems and need further evaluation with bigger subjects.

  20. Growth inhibition and microcystin degradation effects of Acinetobacter guillouiae A2 on Microcystis aeruginosa.

    Science.gov (United States)

    Yi, Yang-Lei; Yu, Xiao-Bo; Zhang, Chao; Wang, Gao-Xue

    2015-01-01

    Strain A2 with algicidal activity against Microcystis aeruginosa was isolated and identified with the genus Acinetobacter on the basis of phenotypic tests and 16S rRNA gene analysis. It was identified with the species Acinetobactor guillouiae by partial rpoB sequence analysis. When 10% (v/v) of the bacterial culture was co-incubated with M. aeruginosa culture, algicidal efficiency reached 91.6% after 7 days. Supernatant of A2 culture showed similar algicidal activity, while the cell pellet had little activity, suggesting that Acinetobacter guillouiae A2 indirectly attacked M. aeruginosa cells by secreting an extracellular algicidal compound, which was characterized as heat-stable. A significant decrease in the microcystin (microcystin-LR) concentration was observed after 10% (v/v) addition of A2 culture. Transcription of three microcystin-related genes (mcyA, mcyD and mcyH) was also found to be inhibited. The algicidal compound 4-hydroxyphenethylamine was obtained by further isolation and purification using various chromatographic techniques. The EC50, 3d and EC50, 7d values of 4-hydroxyphenethylamine against M. aeruginosa were 22.5 and 10.3 mgL(-1), respectively. These results indicate that A. guillouiae strain A2 inhibits growth of M. aeruginosa and degrades microcystin production. The identified compound, 4-hydroxyphenethylamine, has potential for development as a new algicidal formulation or product.

  1. Emergence of Acinetobacter pittii harboring New Delhi metallo-beta-lactamase genes in Daejeon, Korea.

    Science.gov (United States)

    Sung, Ji Youn; Koo, Sun Hoe; Kim, Semi; Kwon, Gye Cheol

    2015-09-01

    Carbapenemase production has been reported worldwide in gram-negative bacteria, including Acinetobacter species. We detected carbapenemase-producing Acinetobacter pittii in clinical isolates in Daejeon, Korea. Twenty-one ertapenem-resistant A. pittii isolates screened with a disk diffusion method were characterized by using the Epsilon test, four multiplex PCR assays, and a multilocus sequence typing (MLST) scheme. A total of 21 A. pittii isolates harbored the metallo-β-lactamase (MBL) gene bla(IMP-1) or bla(NDM-1). Nineteen isolates containing bla(IMP-1) were resistant to imipenem and meropenem, but two isolates harboring bla(NDM-1) were susceptible to them. The sequence types (STs) of the two New Delhi MBL (NDM-1)-producing A. pittii isolates were ST70 and ST207, which differed from the STs (ST63, ST119, ST396, and a novel ST) of the IMP-1-producing A. pittii. This is the first report on NDM-1-producing A. pittii isolates in Korea. Our results emphasize that the study of NDM-1-producing gram-negative bacteria should involve carbapenem-susceptible as well as carbapenem-resistant isolates.

  2. Novel use of antimicrobial hand sanitizer in treatment of nosocomial acinetobacter infection.

    Science.gov (United States)

    Donahue, Meghan; Watson, Luke R; Torress-Cook, Alfonso; Watson, Paul A

    2009-01-01

    Colonization of wounds with multidrug-resistant organisms is a difficult orthopedic problem. Acinetobacter infections are especially difficult because they are resistant to all currently available antibiotics. We present the use of a novel skin sanitizer, Stay Byotrol Clean (Byotrol Inc, Spartanburg, South Carolina), to treat a multidrug-resistant wound infection. A 31-year-old T10 paraplegic man presented with chronic bilateral stage IV decubitus trochanteric ulcers. Cultures grew methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The ulcers were initially treated with irrigation and debridement and vancomycin, levaquin, and cefepime. After 4 months of aggressive treatment, the cultures continued to be positive for Escherichia coli and Acinetobacter baumannii. The patient was started on amikacin and tigecycline. Despite 1 additional month of aggressive wound care, debridements, and intravenous antibiotics, the cultures continued to grow A baumannii and Pseudomonas aerug. The A baumannii was resistant to all available antibiotics tested. The ulcers were then treated with daily application of Stay Byotrol Clean hand and skin sanitizer. Four days later, cultures were negative for any bacterial growth, with no A baumannii. After 1 week, the ulcers showed new granulation tissue with no visible necrotic tissue. After 3 months of treatment, the ulcers had healed. Stay Byotrol Clean is nonirritating and contains no iodine or alcohol. It is currently being used for decolonization of patients on admission to the hospital, however, there is great potential for its use in wound treatment, preoperative surgical sterilization, and orthopedic devices.

  3. Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

    Institute of Scientific and Technical Information of China (English)

    Ebrahim Babapour; Azam Haddadi; Reza Mirnejad; Seyed-Abdolhamid Angaji; Nour Amirmozafari

    2016-01-01

    Objective: To check biofilm formation by Acinetobacter baumannii(A. baumannii)clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance.Methods: This study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Identifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods: culture on Congo red agar, microtiter plate, and test tube method.Results: From the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B.Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar.However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respectively. At least 92% of the biofilm forming isolates were multidrug resistant.Conclusions: Since most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment.

  4. Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

    Institute of Scientific and Technical Information of China (English)

    Ebrahim Babapour; Azam Haddadi; Reza Mirnejad; Seyed-Abdolhamid Angaji; Nour Amirmozafari

    2016-01-01

    Objective: To check biofilm formation by Acinetobacter baumannii (A. baumannii) clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance. Methods: This study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Iden-tifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods:culture on Congo red agar, microtiter plate, and test tube method. Results: From the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B. Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar. However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respec-tively. At least 92%of the biofilm forming isolates were multidrug resistant. Conclusions: Since most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment.

  5. Transcriptional Analysis of Acinetobacter sp. neg1 Capable of Degrading Ochratoxin A

    Science.gov (United States)

    Liuzzi, Vania C.; Fanelli, Francesca; Tristezza, Mariana; Haidukowski, Miriam; Picardi, Ernesto; Manzari, Caterina; Lionetti, Claudia; Grieco, Francesco; Logrieco, Antonio F.; Thon, Michael R.; Pesole, Graziano; Mulè, Giuseppina

    2017-01-01

    Ochratoxin A (OTA) is a nephrotoxic and potentially carcinogenic mycotoxin produced by several species of Aspergillus and Penicillium, contaminating grapes, wine and a variety of food products. We recently isolated from OTA contaminated soil vineyard a novel free-living strain of Acinetobacter sp. neg1, ITEM 17016, able to degrade OTA into the non-toxic catabolic product ochratoxin α. Biochemical studies suggested that the degradation reaction proceeds via peptide bond hydrolysis with phenylalanine (Phe) release. In order to identify genes responsible for OTA degradation we performed a differential gene expression analysis of ITEM 17016 grown in the presence or absence of the toxin. Among the differentially expressed genes, six peptidases up-regulated at 6 h were identified. The degrading activity of the carboxypeptidase PJ_1540 was confirmed in vitro in a heterologous system. The enrichment analysis for Gene Ontology terms confirmed that OTA degradation proceeds through peptidase activities and revealed the over-representation of pathways related to Phe catabolism. These results indicate that Phe may represent an energy source for this Acinetobacter sp. neg1 strain and that OTA degrading reaction triggers the modulation of further catabolic activities. PMID:28119679

  6. Research of Acinetobacter Baumannii Isolation From Clinical Samples in Second Step Hospital

    Directory of Open Access Journals (Sweden)

    Keramettin Yanik

    2015-11-01

    Full Text Available Aim: Due to existing multi drug resistance and subsequently acquired resistance Acinetobacter genus bacteria continuously actual. Other characteristics are increasing treatment costs, patient hospitalization period, mortality and morbidity. Risk factors like extended hospitalization period, background immune system disorders are increasing isolation frequency of this bacteria from patients. Extended spectrum antibiotic usage is known to be a major risk factor. Aim of our study is to investigate cause of growing A.baumanii isolation rate and cross contamination between this isolates in a state hospital. Material and Method: In this study analysed increasing isolation frequency by years and specimen occurrence in level 2 hospital. At the same time detected amount of used imipenem and meropenem in hospital during last three years. A.baumanii strains isolated from respiratory and sputum specimens of patients from intensive care unit and thoracal departament during last month of 2013 year%u2019s were tested using PFGE method for genotypic similarity. Results: Acinetobacters isolation frequency in years and carbapenem usage are subsequently increased. Specimens are generally from respiratory tract. Genotypic similarity not detected on studied 6 A.baumanii strain%u2019s PFGE image. This condition interpreted like this strains origins not from cross contamination.

  7. CipA of Acinetobacter baumannii Is a Novel Plasminogen Binding and Complement Inhibitory Protein.

    Science.gov (United States)

    Koenigs, Arno; Stahl, Julia; Averhoff, Beate; Göttig, Stephan; Wichelhaus, Thomas A; Wallich, Reinhard; Zipfel, Peter F; Kraiczy, Peter

    2016-05-01

    Acinetobacter baumannii is an emerging opportunistic pathogen, responsible for up to 10% of gram-negative, nosocomial infections. The global increase of multidrug-resistant and pan-resistant Acinetobacter isolates presents clinicians with formidable challenges. To establish a persistent infection,A. baumannii must overcome the detrimental effects of complement as the first line of defense against invading microorganisms. However, the immune evasion principles underlying serum resistance inA. baumannii remain elusive. Here, we identified a novel plasminogen-binding protein, termed CipA. Bound plasminogen, upon conversion to active plasmin, degraded fibrinogen and complement C3b and contributed to serum resistance. Furthermore, CipA directly inhibited the alternative pathway of complement in vitro, irrespective of its ability to bind plasminogen. A CipA-deficient mutant was efficiently killed by human serum and showed a defect in the penetration of endothelial monolayers, demonstrating that CipA is a novel multifunctional protein that contributes to the pathogenesis ofA. baumannii.

  8. Identification of Tet 39, a novel class of tetracycline resistance determinant in Acinetobacter spp. of environmental and clinical origin

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Guardabassi, L.

    2005-01-01

    A novel tetracycline resistance determinant named Tet 39 was found in unrelated Acinetobacter strains isolated from freshwater trout farms (n=4) and sewage (n=6) in Denmark, and from a clinical specimen in the Netherlands (n=1). The determinant was located on transferable plasmids and consisted o...

  9. Rapid discrimination of Acinetobacter baumannii international clone II lineage by pyrosequencing SNP analyses of bla(OXA-51-like) genes.

    Science.gov (United States)

    Matsui, Mari; Suzuki, Satowa; Suzuki, Masato; Arakawa, Yoshichika; Shibayama, Keigo

    2013-08-01

    We found that Acinetobacter baumannii international clone II generally possesses unique GTA sequence at nucleotide positions 106-108 in the bla(OXA-51-like) genes. We exploited this to develop an easy and rapid method for discrimination of international clone II from other A. baumannii by employing pyrosequencing analyses of single nucleotide polymorphisms.

  10. Determination antimicrobial resistance profile of Acinetobacter strains isolated from hospitalized patients in Different Part of Taleghani Hospital (Ahvaz, Iran

    Directory of Open Access Journals (Sweden)

    Khadijah Ahmadi

    2014-10-01

    Full Text Available Background: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections such as meningitis, endocarditis, skin and soft tissue infections, urinary tract infection, conjunctivitis, burn wound infection and bacteremia. This organism has been shown resistance to different antimicrobial agents. The aim of this study was to determination antibiotic resistance profile of Acinetobacter strains isolated from hospitalized patients in Taleghani hospital (Ahvaz, Iran. Materials and Methods: This cross-sectional study was conducted on 43 Acinetobacter strains isolated from hospitalized patients. Clinical specimens were cultured on microbiological media. Subsequently, drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Results: Acinetobacter strains were isolated from different specimens consisting biopsy 24 (55.8%, wound 13 (30/2% and blood 6 (14%. In antimicrobial susceptibility testing, colistin exhibited the greatest activity (60.5% against isolated strains. 33 (76/7% isolates demonstrated resistance to imipenem. Conclusion: In outbreak situations, surveillance cultures of patients involved in the outbreak or who are deemed at risk for colonization/infection with the outbreak organism are often parts of the planned intervention.

  11. Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites.

    Science.gov (United States)

    Silambarasan, Sivagnanam; Vangnai, Alisa S

    2016-01-25

    4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μmax, Ks and Ki, were determined to be 0.039 h(-1), 6.623 mg L(-1) and 25.57 mg L(-1), respectively using Haldane inhibition model, while the maximum biodegradation rate (Vmax) of 4-NA was at 0.541 mg L(-1) h(-1) and 0.551 mg L(-1) h(-1), following Michaelis-Menten and Hanes-Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment.

  12. A distinct alleles and genetic recombination of pmrCAB operon in species of Acinetobacter baumannii complex isolates.

    Science.gov (United States)

    Kim, Dae Hun; Ko, Kwan Soo

    2015-07-01

    To investigate pmrCAB sequence divergence in 5 species of Acinetobacter baumannii complex, a total of 80 isolates from a Korean hospital were explored. We evaluated nucleotide and amino acid polymorphisms of pmrCAB operon, and phylogenetic trees were constructed for each gene of prmCAB operon. Colistin and polymyxin B susceptibility was determined for all isolates, and multilocus sequence typing was also performed for A. baumannii isolates. Our results showed that each species of A. baumannii complex has divergent pmrCAB operon sequences. We identified a distinct pmrCAB allele allied with Acinetobacter nosocomialis in gene trees. Different grouping in each gene tree suggests sporadic recombination or emergence of pmrCAB genes among Acinetobacter species. Sequence polymorphisms among Acinetobacter species might not be associated with colistin resistance. We revealed that a distinct pmrCAB allele may be widespread across the continents such as North America and Asia and that sporadic genetic recombination or emergence of pmrCAB genes might occur.

  13. Whole-genome pyrosequencing of an epidemic multidrug-resistant Acinetobacter baumannii strain belonging to the European clone II group

    DEFF Research Database (Denmark)

    Iacono, M.; Villa, L.; Fortini, D.

    2008-01-01

    The whole-genome sequence of an epidemic, multidrug-resistant Acinetobacter baumannii strain (strain ACICU) belonging to the European clone II group and carrying the plasmid-mediated bla(OXA-58) carbapenem resistance gene was determined. The A. baumannii ACICU genome was compared with the genomes...

  14. A data-driven mathematical model of multi-drug resistant Acinetobacter baumannii transmission in an intensive care unit

    NARCIS (Netherlands)

    Wang, Xia; Chen, Yong; Zhao, Wei; Wang, Yan; Song, Qing; Liu, Hui; Zhao, Jingya; Han, Xuelin; Hu, Xiaohua; Grundmann, Hajo; Xiao, Yanni; Han, Li

    2015-01-01

    Major challenges remain when attempting to quantify and evaluate the impacts of contaminated environments and heterogeneity in the cohorting of health care workers (HCWs) on hospital infections. Data on the detection rate of multidrug-resistant Acinetobacter baumannii (MRAB) in a Chinese intensive c

  15. Genome Sequence of vB_AbaS_TRS1, a Viable Prophage Isolated from Acinetobacter baumannii Strain A118.

    Science.gov (United States)

    Turner, Dann; Wand, Matthew E; Sutton, J Mark; Centron, Daniela; Kropinski, Andrew M; Reynolds, Darren M

    2016-10-13

    A novel temperate phage, vB_AbaS_TRS1, was isolated from cultures of Acinetobacter baumannii strain A118 that had been exposed to mitomycin C. Phage TRS1 belongs to the Siphoviridae family of bacteriophages and encapsulates a 40,749-bp genome encoding 70 coding sequences and a single tRNA.

  16. 不动杆菌的耐药性分析%Analysis of Antibiotic Resistance of Acinetobacter Spp

    Institute of Scientific and Technical Information of China (English)

    崔嫚; 严兴耘; 郗建良; 张全华

    2012-01-01

    调查2010~2011年临床分离不动杆菌分布及耐药情况.按常规方法培养分离细菌,用VITEK32进行细菌鉴定和药敏,用纸片扩散法做补充药敏实验.结果显示临床不动杆菌分离率高,分离率>11%.分离标本主要为痰和咽拭子,构成比>80%.以鲍曼不动杆菌为主,构成比>75%.不动杆菌耐药广泛,对临床常见药物大多表现较高的耐药率,耐药率>50%.头孢哌酮/舒巴坦耐药率较低,耐药率<5%.治疗的推荐方案多用替加环素、碳青酶烯类联合舒巴坦、多粘菌素联合利福平或阿米卡星等.%To investigate the drug resistance rate of strains isolated from nosocomial infection paients with acinetobacter spp. Using conventional methods to isolate bacteria, using VITEK 32 microbiological analyzer to identify the bacteria and test drug sensitivity, using disc diffusion to study supplementary antimicrobial resistance. The results showed that acinetobacter spp isolated rate was high,the rate was >ll%. The acinetobacter spp were mainly isolated from sputum and pharyngeal swab, the constituent ratio was >80%. The main isolated of acinetobacter spp was bauman acinetobacter and the constituent ratio was >75%. Acinetobacter spp were multiple drug resistance widely,they mostly exhibited higher durg resistance rate 050%) on common clinical drugs. The durg resistance rate of cefoperazone/shubatan was low (<5%). The recommended drugs of treatment acinetobacter spp are tigecyclinccarbapenem combined with shuba-tan,polymyxin combined with rifampicin or amikacin.

  17. 鲍曼不动杆菌耐药性分析%Analysis of antibiotics resistance of Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    李海峰; 王志刚; 夏娴; 卓晓; 樊林科

    2012-01-01

    Objective:To investigate the distribution of Acinetobacter baumannii and the variation of its antibiotics resistance feature. Methods:The Acinetobacter baumannii were cultivated and isolated from the inspection specimens of inpatients received during January 2006 to December 2010, and the VITEK - 2 automatic microbial analyzer was used to perform the bacteria identification and drug sensitivity test. Results:The detection rate of Acinetobacter baumannii grew year by year. The antibiotics resistance rate of Acinetobacter baumannii also increased, nearly resistant to all tested antibiotics except Amikacin. Conclusion:The detection rate and the antibiotics resistance rate of Acinetobacter baumannii both increased year by year.%目的:了解鲍曼不动杆菌的分布及耐药性变迁情况.方法:调查2006年1月-2010年12月住院病人送检标本中培养分离出的鲍曼不动杆菌,利用VITEK -2型全自动微生物分析仪进行细菌鉴定和药敏试验.结果:鲍曼不动杆菌检出率呈逐年上升趋势.该菌对抗菌药物的耐药率亦呈逐年上升趋势,除丁胺卡那霉素外已接近几乎全部耐药.结论:鲍曼不动杆菌的检出率及耐药率逐年上升.

  18. In vitro and in vivo analysis of antimicrobial agents alone and in combination against multi-drug resistant Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Songzhe eHE

    2015-05-01

    Full Text Available Objective To investigate the in vitro and in vivo antibacterial activities of tigecycline and other 13 common antimicrobial agents, alone or in combination, against multi-drug resistant Acinetobacter baumannii.MethodsAn in vitro susceptibility test of 101 Acinetobacter baumannii was used to detect minimal inhibitory concentrations (MICs. A mouse lung infection model of multi-drug resistant Acinetobacter baumannii,established by the ultrasonic atomization method, was used to define in vivo antimicrobial activities.Results Multi-drug resistant Acinetobacter baumannii showed high sensitivity to tigecycline (98% inhibition, polymyxin B (78.2% inhibition, and minocycline (74.2% inhibition. However, the use of these antimicrobial agents in combination with other antimicrobial agents produced synergistic or additive effects. In vivo data showed that white blood cell (WBC counts in drug combination groups C (minocycline + amikacin and D (minocycline + rifampicin were significantly higher than in groups A (tigecycline and B (polymyxin B (P < 0.05, after administration of the drugs 24h post-infection. Lung tissue inflammation gradually increased in the model group during the first 24h after ultrasonic atomization infection; vasodilation, congestion with hemorrhage were observed 48h post infection. After three days of anti-infective therapy in groups A, B, C and D, lung tissue inflammation in each group gradually recovered with clear structures. The mortality rates in drug combination groups (groups C and D were much lower than in groups A and B.ConclusionThe combination of minocycline with either rifampicin or amikacin is more effective against multidrug-resistant Acinetobacter baumannii than single-agent tigecycline or polymyxin B. In addition, the mouse lung infection by ultrasonic atomization is a suitable model for drug screening and analysis of infection mechanism.

  19. Ventilator Associated Pneumonia in a Military Deployed Setting: The Impact of an Aggressive Infection Control Program

    Science.gov (United States)

    2008-02-01

    A, et al. An outbreak of multi-drug resistant Acinetobacter baumannii -calcoaceticus complex infections in the U.S. military health-care system...resistant Acinetobacter baumannii associated with pulsatile lavage wound treatment. JAMA. 2004;292:3006–3011. 7. Urban C, Segal-Maurer S, Rahal JJ...Considerations in control and treatment of nosocomial infections due to multidrug-resistant Acinetobacter baumannii . Clin Infect Dis. 2003;36:1268–1274. 8

  20. Axioms Altered With Research

    Science.gov (United States)

    2012-08-01

    Prevention (CDC): Acinetobacter baumannii infections among patients at military medical facilities treating injured U.S. service members, 2002–2004. MMWR...outbreak of multidrug-resistant Acinetobacter baumannii -calcoaceticus complex infection in the US military health care system associated with military...operations in Iraq. Clin Infect Dis 2007;44(12):1577-1584. 10. Turton JF, Kaufmann ME, Gill MJ, et al: Comparison of Acinetobacter baumannii isolates from

  1. Metallo-β-lactamase-producing clinical isolates of Acinetobacter species and Pseudomonas aeruginosa from intensive care unit patients of a tertiary care hospital

    Directory of Open Access Journals (Sweden)

    Irfan S

    2008-01-01

    Full Text Available Prompt detection of metallo-β-lactamase (MBL producing isolates is necessary to prevent their dissemination. Frequency of MBLs producing strains among multidrug resistant (MDR Acinetobacter species and Pseudomonas aeruginosa was evaluated in critical care patients using imipenem-EDTA disk method. One hundred MDR Acinetobacter spp. and 42 Pseudomonas aeruginosa were checked for MBL production, from January to June 2001. MBL was produced by 96.6 % of imipenem-resistant Acinetobacter isolates, whereas 100% imipenem-resistant Pseudomonas aeroginosa isolates were MBL producers. Carbapenem resistance in MDR Acinetobacter spp. and Pseudomonas aeruginosa isolates in this study was due to MBLs. This calls for strict infection control measures to prevent further dissemination.

  2. Species distribution and physiological characterization of Acinetobacter genospecies from healthy human skin of tribal population in India

    OpenAIRE

    Yavankar S; Pardesi K; Chopade B

    2007-01-01

    Background: Various reports on distribution of Acinetobacter spp. from healthy human skin restricted to urban population. However, no such data is available from healthy human skin of tribal population not exposed to modern antibiotics during their life time. Purpose: Isolation, biotyping, distribution and physiological characterisation of Acinetobacter spp. from healthy human skin of tribal population. Methods: Tribal population of Toranmal area of Satpuda Ranges, Maharashtra, India...

  3. AmiE, a novel N-acylhomoserine lactone acylase belonging to the amidase family, from the activated-sludge isolate Acinetobacter sp. strain Ooi24.

    Science.gov (United States)

    Ochiai, Seiji; Yasumoto, Sera; Morohoshi, Tomohiro; Ikeda, Tsukasa

    2014-11-01

    Many Gram-negative bacteria use N-acyl-l-homoserine lactones (AHLs) as quorum-sensing signal molecules. We have reported that Acinetobacter strains isolated from activated sludge have AHL-degrading activity. In this study, we cloned the amiE gene as an AHL-degradative gene from the genomic library of Acinetobacter sp. strain Ooi24. High-performance liquid chromatography analysis revealed that AmiE functions as an AHL acylase, which hydrolyzes the amide bond of AHL. AmiE showed a high level of degrading activity against AHLs with long acyl chains but no activity against AHLs with acyl chains shorter than eight carbons. AmiE showed homology with a member of the amidases (EC 3.5.1.4) but not with any known AHL acylase enzymes. An amino acid sequence of AmiE from Ooi24 showed greater than 99% identities with uncharacterized proteins from Acinetobacter ursingii CIP 107286 and Acinetobacter sp. strain CIP 102129, but it was not found in the draft or complete genome sequences of other Acinetobacter strains. The presence of transposase-like genes around the amiE genes of these three Acinetobacter strains suggests that amiE is transferred by a putative transposon. Furthermore, the expression of AmiE in Pseudomonas aeruginosa PAO1 reduced AHL accumulation and elastase activity, which were regulated by AHL-mediated quorum sensing.

  4. Synergistic activity of coriander oil and conventional antibiotics against Acinetobacter baumannii.

    Science.gov (United States)

    Duarte, A; Ferreira, S; Silva, F; Domingues, F C

    2012-02-15

    In this study we investigated the existence of synergistic antibacterial effect between coriander (Coriandrum sativum L.) essential oil and six different antibacterial drugs (cefoperazone, chloramphenicol, ciprofloxacin, gentamicin, tetracycline and piperacillin). The antibacterial activity of coriander oil was assessed using microdilution susceptibility testing and synergistic interaction by checkerboard assays. The association of coriander essential oil with chloramphenicol, ciprofloxacin, gentamicin and tetracycline against Acinetobacter baumannii showed in vitro effectiveness, which is an indicator of a possible synergistic interaction against two reference strains of A. baumannii (LMG 1025 and LMG 1041) (FIC index from 0.047 to 0.375). However, when tested the involvement between coriander essential oil and piperacillin or cefoperazone, the isobolograms and FIC index showed an additive interaction. The in vitro interaction could improve the antimicrobial effectiveness of ciprofloxacin, gentamicin and tetracycline and may contribute to resensitize A. baumannii to the action of chloramphenicol.

  5. Carbapenem resistance in Acinetobacter baumannii: laboratory challenges, mechanistic insights and therapeutic strategies.

    Science.gov (United States)

    Abbott, Iain; Cerqueira, Gustavo M; Bhuiyan, Saruar; Peleg, Anton Y

    2013-04-01

    Unprecedented levels of antimicrobial resistance in bacterial isolates have prompted great concerns globally. In 2012 the WHO released a publication outlining the evolving threat of antimicrobial resistance in order to raise awareness and to stimulate coordinated international efforts. The carbapenem class of antibiotics is largely considered as an antibiotic of last-resort when treating infections. Now carbapenem resistance further limits treatment options. In this article the authors discuss carbapenem resistance in Acinetobacter baumannii, a bacterial isolate often implicated in nosocomial infections. Virulence factors, intrinsic and acquired resistance mechanisms, together with laboratory challenges in the detection and antibiotic susceptibility testing of A. baumannii make this a truly problematic isolate. Therapeutic options are exceedingly limited, relying on polymyxins in combinations with other antibiotics, with few, if any, new active agents in the pipeline.

  6. Insights into the global molecular epidemiology of carbapenem non-susceptible clones of Acinetobacter baumannii.

    Science.gov (United States)

    Karah, Nabil; Sundsfjord, Arnfinn; Towner, Kevin; Samuelsen, Ørjan

    2012-08-01

    The global emergence of multidrug resistance (MDR) among Gram-negative bacteria has dramatically limited the therapeutic options. During the last two decades, Acinetobacter baumannii has become a pathogen of increased clinical importance due to its remarkable ability to cause outbreaks of infections and to acquire resistance to almost all currently used antibiotics, including the carbapenems. This review considers the literature on A. baumannii and data from multilocus sequence typing studies to explore the global population structure of A. baumannii and detect the occurrence of clonality, with the focus on the presence of specific resistance mechanisms such as the OXA-carbapenemases. The worldwide dissemination of MDR and carbapenem non-susceptible A. baumannii is associated with diverse genetic backgrounds, but predominated by a number of extensively distributed clones, such as CC92(B)/CC2(P) and CC109(B)/CC1(P), which have frequently been supplemented by acquired OXA-type carbapenemase genes.

  7. Antibacterial activity of copper-containing clinoptilolite/PVC composites toward clinical isolate of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Milenković Jelena K.

    2015-01-01

    Full Text Available The multidrug resistant bacteria Acinetobacter baumannii cause serious hospital infections. Commercial poly(vinyl chloride (PVC used for endotracheal tubes was modified in order to obtain the composite with antibacterial effect towards clinical isolate of A. baumannii ST145. The composites were prepared by addition of different amounts of copper-containing zeolite tuff (CuZ and by successive impregnation with D-Tyrosine (D-Tyr solution. The composites which were obtained by addition of CuZ (CuZ-PVC only did not exhibit antibacterial effect. The impregnation of the CuZ-PVC by D-Tyr resulted in an antibacterial effect which is explained by a synergistic effect of CuZ and D-Tyr. Rheological tests confirmed that the modification of PVC by CuZ does not affect its processability and reformability. [Projekat Ministarstva nauke Republike Srbije, br. 172018

  8. Enhancing the hexavalent chromium bioremediation potential of Acinetobacter junii VITSUKMW2 using statistical design experiments.

    Science.gov (United States)

    Pulimi, Mrudula; Jamwal, Subika; Samuel, Jastin; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2012-12-01

    The Cr(VI) removal capability of Acinetobacter junii VITSUKMW2 isolated from the Sukinda chromite mine site was evaluated and enhanced using statistical design techniques. The removal capacity was evaluated at different pH values (5-11) and temperatures (30-40 degrees C) and with various carbon and nitrogen sources. Plackett- Burman design was used to select the operational parameters for bioremediation of Cr(VI). Three parameters (molasses, yeast extract, and Cr(VI) concentration) were chosen for further optimization using central composite design. The optimal combination of parameters was found to be 14.85 g/l molasses, 4.72 g/l yeast extract, and 54 mg/l initial Cr(VI), with 99.95% removal of Cr(VI) in 12 h. A. junii VITSUKMW2 was shown to have significant potential for removal of Cr(VI).

  9. Distribution of AdeABC efflux system genes in genotypically diverse strains of clinical Acinetobacter baumannii.

    Science.gov (United States)

    Wieczorek, Piotr; Sacha, Paweł; Czaban, Sławomir; Hauschild, Tomasz; Ojdana, Dominika; Kowalczuk, Oksana; Milewski, Robert; Poniatowski, Bogusław; Nikliński, Jacek; Tryniszewska, Elżbieta

    2013-10-01

    Acinetobacter baumannii has emerged as a highly problematic hospital-associated pathogen. Different mechanisms contribute to the formation of multidrug resistance in A. baumannii, including the AdeABC efflux system. Distribution of the structural and regulatory genes encoding the AdeABC efflux system among genetically diverse clinical A. baumannii strains was achieved by using PCR and pulsed-field gel electrophoresis techniques. The distribution of adeABRS genes is extremely high among our A. baumannii strains, except the adeC gene. We have observed a large proportion of strains presenting multidrug-resistance phenotype for several years. The efflux pump could be an important mechanism in these strains in resistance to antibiotics.

  10. Genomic Island Location in Acinetobacter baumannii Strains by tRIP-PCR Technique

    Directory of Open Access Journals (Sweden)

    Suhadsaad

    2013-11-01

    Full Text Available This study was performed to detect the presence of genomic islands which usually insert in the tRNA genes and other non-coding RNA genes, in this study eight strains of Acinetobacter baumannii (AYE, A457, A14, A424 A473, A92, ACICU, A25 were tested by used of tRIP-(tRNA site Interrogation for Pathogeni city islands, prophases and other GIs-PCR method. The results of PCR and agarose gel electrophoresis for eight strains of two loci #7, #24 were: the results of #7 loci screening showed that all strains were positive except A. baumannii 457 strain was negative. While the results of #24 loci showed presence of foreign DNA in A. baumannii AYE, A457, A14, A424, A473, A92 except the results of (ACICU, A25 was positive.

  11. Isolation and characterization of diesel degrading bacteria, Sphingomonas sp. and Acinetobacter junii from petroleum contaminated soil

    Science.gov (United States)

    Zhang, Qiuzhuo; Wang, Duanchao; Li, Mengmeng; Xiang, Wei-Ning; Achal, Varenyam

    2014-03-01

    Two indigenous bacteria of petroleum contaminated soil were characterized to utilize diesel fuel as the sole carbon and energy sources in this work. 16S rRNA gene sequence analysis identified these bacteria as Sphingomonas sp. and Acinetobacter junii. The ability to degrade diesel fuel has been demonstrated for the first time by these isolates. The results of IR analyses showed that Sphingomonas sp. VA1 and A. junii VA2 degraded up to 82.6% and 75.8% of applied diesel over 15 days, respectively. In addition, Sphingomonas sp. VA1 possessed the higher cellular hydrophobicities of 94% for diesel compared to 81% by A. junii VA2. The isolates Sphingomonas sp. VA1 and A. junii VA2 exhibited 24% and 18%, respectively emulsification activity. This study reports two new diesel degrading bacterial species, which can be effectively used for bioremediation of petroleum contaminated sites.

  12. Effect of Acinetobacter glutaminase-asparaginase treatment on free amino acids in mouse tissues.

    Science.gov (United States)

    Holcenberg, J S; Tang, E; Dolowy, W C

    1975-05-01

    Acinetobacter glutaminase-asparaginase (AGA) and Escherichia coli asparaginase were compared for their effects on plasma and tissue levels of amino acids, ammonia, and glutamyl transferase activity in the mouse. Free asparagine was depleted similarly in plasma and tissues by both enzymes. AGA treatment produced partial depletion of glutamine concentrations in muscle, spleen, small intestine, and liver. Brain and kidney glutamine concentrations actually rose with treatment. Despite over 100-fold increase in plasma glutamate, only the kidney showed a substantial increase in free glutamate levels during AGA treatment. Glutamine biosynthesis measured by glutamyl transferase activity showed an appreciable increase only in the kidney. Ammonia levels in tissues and plasma rose 1.3- to 4.3-fold. In general, E. coli asparaginase treatment had much less effect on these measurements than did AGA. The changes in these levels are discussed in relation to sites of possible toxicity and antitumor effects.

  13. Ultrafast Structural Dynamics of BlsA, a Photoreceptor from the Pathogenic Bacterium Acinetobacter baumannii

    Science.gov (United States)

    2013-01-01

    Acinetobacter baumannii is an important human pathogen that can form biofilms and persist under harsh environmental conditions. Biofilm formation and virulence are modulated by blue light, which is thought to be regulated by a BLUF protein, BlsA. To understand the molecular mechanism of light sensing, we have used steady-state and ultrafast vibrational spectroscopy to compare the photoactivation mechanism of BlsA to the BLUF photosensor AppA from Rhodobacter sphaeroides. Although similar photocycles are observed, vibrational data together with homology modeling identify significant differences in the β5 strand in BlsA caused by photoactivation, which are proposed to be directly linked to downstream signaling. PMID:24723998

  14. The role of ISAba1 in expression of OXA carbapenemase genes in Acinetobacter baumannii.

    Science.gov (United States)

    Turton, Jane F; Ward, M Elaina; Woodford, Neil; Kaufmann, Mary E; Pike, Rachel; Livermore, David M; Pitt, Tyrone L

    2006-05-01

    ISAba1 was found in all widespread clones of Acinetobacter baumannii in the United Kingdom. All isolates studied had a blaOXA-51-like carbapenemase gene; some also had blaOXA-23-like and/or blaOXA-58-like. Among isolates with blaOXA-51-like as sole carbapenemase gene, only those with ISAba1 adjacent to blaOXA-51-like were carbapenem resistant. Minor differences in blaOXA-51-like sequence were observed in resistant and susceptible isolates. Isolates with blaOXA-23-like in addition were consistently resistant to carbapenems; in all of these ISAba1 lay upstream of blaOXA-23-like, but was not associated with blaOXA-51-like. These results suggest that ISAba1 is providing the promoter for blaOXA-51-like and, probably, for blaOXA-23-like.

  15. Biology of Acinetobacter baumannii: Pathogenesis, Antibiotic Resistance Mechanisms, and Prospective Treatment Options

    Science.gov (United States)

    Lee, Chang-Ro; Lee, Jung Hun; Park, Moonhee; Park, Kwang Seung; Bae, Il Kwon; Kim, Young Bae; Cha, Chang-Jun; Jeong, Byeong Chul; Lee, Sang Hee

    2017-01-01

    Acinetobacter baumannii is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant A. baumannii, few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of A. baumannii is important. In this review, we summarize current studies on the virulence factors that contribute to A. baumannii pathogenesis, including porins, capsular polysaccharides, lipopolysaccharides, phospholipases, outer membrane vesicles, metal acquisition systems, and protein secretion systems. Mechanisms of antibiotic resistance of this organism, including acquirement of β-lactamases, up-regulation of multidrug efflux pumps, modification of aminoglycosides, permeability defects, and alteration of target sites, are also discussed. Lastly, novel prospective treatment options for infections caused by multi-drug resistant A. baumannii are summarized. PMID:28348979

  16. Effects of silver nanoparticles in combination with antibiotics on the resistant bacteria Acinetobacter baumannii.

    Science.gov (United States)

    Wan, Guoqing; Ruan, Lingao; Yin, Yu; Yang, Tian; Ge, Mei; Cheng, Xiaodong

    2016-01-01

    Acinetobacter baumannii resistance to carbapenem antibiotics is a serious clinical challenge. As a newly developed technology, silver nanoparticles (AgNPs) show some excellent characteristics compared to older treatments, and are a candidate for combating A. baumannii infection. However, its mechanism of action remains unclear. In this study, we combined AgNPs with antibiotics to treat carbapenem-resistant A. baumannii (aba1604). Our results showed that single AgNPs completely inhibited A. baumannii growth at 2.5 μg/mL. AgNP treatment also showed synergistic effects with the antibiotics polymixin B and rifampicin, and an additive effect with tigecyline. In vivo, we found that AgNPs-antibiotic combinations led to better survival ratios in A. baumannii-infected mouse peritonitis models than that by single drug treatment. Finally, we employed different antisense RNA-targeted Escherichia coli strains to elucidate the synergistic mechanism involved in bacterial responses to AgNPs and antibiotics.

  17. Comparative Genomic Analysis of Rapid Evolution of an Extreme-Drug-Resistant Acinetobacter baumannii Clone

    DEFF Research Database (Denmark)

    Tan, Sean Yang-Yi; Chua, Song Lin; Liu, Yang

    2013-01-01

    , comparative genomics has been employed to analyze the rapid evolution of an EDR Acinetobacter baumannii clone from the intensive care unit (ICU) of Rigshospitalet at Copenhagen. Two resistant A. baumannii strains, 48055 and 53264, were sequentially isolated from two individuals who had been admitted to ICU...... within a 1-month interval. Multilocus sequence typing indicates that these two isolates belonged to ST208. The A. baumannii 53264 strain gained colistin resistance compared with the 48055 strain and became an EDR strain. Genome sequencing indicates that A. baumannii 53264 and 48055 have almost identical...... genomes—61 single-nucleotide polymorphisms (SNPs) were found between them. The A. baumannii 53264 strain was assembled into 130 contigs, with a total length of 3,976,592 bp with 38.93% GC content. The A. baumannii 48055 strain was assembled into 135 contigs, with a total length of 4,049,562 bp with 39...

  18. Antibiotic resistance determinants of a group of multidrug-resistant Acinetobacter baumannii in China.

    Science.gov (United States)

    Xiao-Min, Xu; You-Fen, Fan; Wei-Yun, Feng; Zu-Huang, Mi; Xing-Bei, Weng

    2014-06-01

    A group of Acinetobacter baumannii confers multidrug resistance, but the molecular epidemiology and multidrug resistance mechanisms are poorly understood. Nineteen isolates were identified, and the antimicrobial susceptibility profile was determined using the disc diffusion method. Then, PCR of 78 kinds of resistance-associated genes were performed. A novel variant of blaADC gene: blaADC-67 gene (Genbank accession No. JX169789) was prevalent in all 19 isolates. Moreover, ISAba1 could also provide strong promoter to upregulate the expression of blaADC67 to confer resistance to beta-lactam. This is the first report of emergence of blaADC-67 in A. baumannii worldwide, which might confer resistance to beta-lactam.

  19. Screening and deciphering antibiotic resistance in Acinetobacter baumannii: a state of the art.

    Science.gov (United States)

    Bonnin, Rémy A; Nordmann, Patrice; Poirel, Laurent

    2013-06-01

    Acinetobacter baumannii, recognized as a serious threat in healthcare facilities, has the ability to develop resistance to antibiotics quite easily. This resistance is related to either gene acquisition (horizontal gene transfer) or mutations in the genome, leading to gene disruption, over- or down-expression of genes. The clinically relevant antibiotic resistances in A. baumannii include resistance to aminoglycosides, broad-spectrum cephalosporins, carbapenems, tigecycline and colistin, which are the last resort antibiotics. The intrinsic and acquired resistance mechanisms of A. baumannii are presented here, with special focus on β-lactam resistance. The most up-to-date techniques for identification, including phenotypical and molecular tests, and screening of those emerging resistance traits are also highlighted. The implementation of early detection and identification of multidrug-resistant A. baumannii is crucial to control their spread.

  20. New Delhi metallo-beta-lactamase-1-producing Acinetobacter spp. infection: report of a survivor.

    Science.gov (United States)

    Schuelter-Trevisol, Fabiana; Schmitt, Graciane Jacinta; Araújo, Jane Martins de; Souza, Liliane Braga de; Nazário, Juliana Gomes; Januário, Raquel Landuchi; Mello, Rogério Sobroza de; Trevisol, Daisson José

    2016-02-01

    New Delhi metallo-beta-lactamase-1 (NDM-1) is a bacterial enzyme that renders the bacteria resistant to a variety of beta-lactam antibiotics. A 20-year-old man was hospitalized several times for surgical treatment and complications caused by a right-sided vestibular schwannoma. Although the patient acquired several multidrug-resistant infections, this study focuses on the NDM-1-producing Acinetobacter spp. infection. As it was resistant to all antimicrobials tested, the medical team developed a 20-day regimen of 750mg/day metronidazole, 2,000,000IU/day polymyxin B, and 100mg/day tigecycline. The treatment was effective, and the patient recovered and was discharged from the hospital.

  1. Characterization of Acinetobacter baumannii from intensive care units and home care patients in Palermo, Italy.

    Science.gov (United States)

    Mammina, C; Bonura, C; Aleo, A; Calà, C; Caputo, G; Cataldo, M C; Di Benedetto, A; Distefano, S; Fasciana, T; Labisi, M; Sodano, C; Palma, D M; Giammanco, A

    2011-11-01

    In this study 45 isolates of Acinetobacter baumannii identified from patients in intensive care units of three different hospitals and from pressure ulcers in home care patients in Palermo, Italy, during a 3-month period in 2010, were characterized. All isolates were resistant to at least three classes of antibiotics, but susceptible to colistin and tygecycline. Forty isolates were non-susceptible to carbapenems. Eighteen and two isolates, respectively, carried the bla(OXA-23-like) and the bla(OXA-58-like) genes. One strain carried the VIM-4 gene. Six major rep-PCR subtype clusters were defined, including isolates from different hospitals or home care patients. The sequence type/pulsed field gel electrophoresis group ST2/A included 33 isolates, and ST78/B the remaining 12. ST2 clone proved to be predominant, but a frequent involvement of the ST78 clone was evident.

  2. A multi-resistant Acinetobacter baumannii outbreak in a general intensive care unit.

    Science.gov (United States)

    Levidiotou, Stamatina; Galanakis, Emmanouil; Vrioni, Georgia; Papamichael, Dimitrios; Nakos, Georgios; Stefanou, Dimitrios

    2002-01-01

    In an Intensive Care Unit, three patients were found infected and two colonized with multiresistant Acinetobacter baumannii within a period of one week. To identify the outbreak source, two surveillance studies were performed concerning patients and the environment. Genotyping of isolates was performed by random amplification of polymorphic DNA analysis (RAPD). Environmental sampling failed to yield A. baumannii, with the exception of a single sample from a trunking. RAPD-fingerprinting yielded identical patterns for all patient isolates including the trunking isolate, thus confirming the suspected cluster. Since the strain from the trunking had a susceptibility pattern and a RAPD pattern identical to that of the strains isolated from the patients, we believe that this was the likely source of the outbreak. In conclusion, A. baumannii outbreaks may be quickly controlled by appropriate action of the hospital infection staff. RAPD-fingerprinting may provide a useful and rapid identification technique for the epidemiological investigation of a hospital outbreak.

  3. 鲍曼不动杆菌耐药性分析%Resistance analysis of Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    申丽婷; 胡艳宁; 韩欣欣; 谢伟峰; 曲彦

    2015-01-01

    目的:了解鲍曼不动杆菌临床分离菌株的耐药现状与耐药谱特征。方法收集分离的70株鲍曼不动杆菌,用K-B纸片法检测抗菌药物的耐药性。结果70株鲍曼不动杆菌中,40株(57.14%)为多重耐药菌,6株(8.57%)为泛耐药菌株。鲍曼不动杆菌对亚胺培南、阿米卡星的耐药率最低,分别为30.00%和32.86%;其次是美罗培南、头胞吡肟,耐药率分别为38.57%,41.43%;对其余抗菌药的耐药率大多超过50.00%。结论本院鲍曼不动杆菌临床分离菌株多重耐药情况严重。%Objective To investigate the antimicrobial resistance and drug-resistant spectrum characteristics of Acinetobacter baumannii clini-cal isolates.Methods Seventy strains of Acinetobacter baumannii were collected, and the K-B disk diffusion method were applied to analyze the antimicrobial resistance. Results Of all Acinetobacter baumannii strains, 40 strains were multi -drug resistant ( 57.14%) and 6 strains were pan-drug resistant ( 8.57%) .The antimicrobial resistant rates of Acinetobacter baumannii to imipenem, amikacin, meropenem and cefepime were 30.00%, 32.86%, 38.57%and 41.43%, respectively, which were lower than others.However, the antimicrobial resistant rates to other commonly used antibiotics were higher than 50.00%.Conclu-sion The multi -drug resistance of Acinetobacter baumannii collected from the hospital was serious, and abaI gene played an important role in the multi-drug resistant mechanism of Acinetobacter baumannii.

  4. Effects of silver nanoparticles in combination with antibiotics on the resistant bacteria Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Wan G

    2016-08-01

    Full Text Available Guoqing Wan,1,2 Lingao Ruan,2,3 Yu Yin,2,3 Tian Yang,2,3 Mei Ge,2 Xiaodong Cheng1,4 1School of Life Science and Technology, China Pharmaceutical University, Nanjing, 2Shanghai Laiyi Center for Biopharmaceutical R&D, 3School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People’s Republic of China; 4Department of Integrative Biology & Pharmacology, The University of Texas Health Science Center, Houston, TX, USA Abstract: Acinetobacter baumannii resistance to carbapenem antibiotics is a serious clinical challenge. As a newly developed technology, silver nanoparticles (AgNPs show some excellent characteristics compared to older treatments, and are a candidate for combating A. baumannii infection. However, its mechanism of action remains unclear. In this study, we combined AgNPs with antibiotics to treat carbapenem-resistant A. baumannii (aba1604. Our results showed that single AgNPs completely inhibited A. baumannii growth at 2.5 µg/mL. AgNP treatment also showed synergistic effects with the antibiotics polymixin B and rifampicin, and an additive effect with tigecyline. In vivo, we found that AgNPs–antibiotic combinations led to better survival ratios in A. baumannii-infected mouse peritonitis models than that by single drug treatment. Finally, we employed different antisense RNA-targeted Escherichia coli strains to elucidate the synergistic mechanism involved in bacterial responses to AgNPs and antibiotics. Keywords: Acinetobacter baumannii, AgNPs, synergistic, antibiotic combination, anti­sense RNA 

  5. Identification of Acinetobacter baumannii serum-associated antibiotic efflux pump inhibitors.

    Science.gov (United States)

    Blanchard, Catlyn; Barnett, Pamela; Perlmutter, Jessamyn; Dunman, Paul M

    2014-11-01

    Adaptive antibiotic resistance is a newly described phenomenon by which Acinetobacter baumannii induces efflux pump activity in response to host-associated environmental cues that may, in part, account for antibiotic treatment failures against clinically defined susceptible strains. To that end, during adaptation to growth in human serum, the organism induces approximately 22 putative efflux-associated genes and displays efflux-mediated minocycline tolerance at antibiotic concentrations corresponding to patient serum levels. Here, we show that in addition to minocycline, growth in human serum elicits A. baumannii efflux-mediated tolerance to the antibiotics ciprofloxacin, meropenem, tetracycline, and tigecycline. Moreover, using a whole-cell high-throughput screen and secondary assays, we identified novel serum-associated antibiotic efflux inhibitors that potentiated the activities of antibiotics toward serum-grown A. baumannii. Two compounds, Acinetobacter baumannii efflux pump inhibitor 1 (ABEPI1) [(E)-4-((4-chlorobenzylidene)amino)benezenesulfonamide] and ABEPI2 [N-tert-butyl-2-(1-tert-butyltetrazol-5-yl)sulfanylacetamide], were shown to lead to minocycline accumulation within A. baumannii during serum growth and inhibit the efflux potential of the organism. While both compounds also inhibited the antibiotic efflux properties of the bacterial pathogen Pseudomonas aeruginosa, they did not display significant cytotoxicity toward human cells or mammalian Ca(2+) channel inhibitory effects, suggesting that ABEPI1 and ABEPI2 represent promising structural scaffolds for the development of new classes of bacterial antibiotic efflux pump inhibitors that can be used to potentiate the activities of current and future antibiotics for the therapeutic intervention of Gram-negative bacterial infections.

  6. Association of plasmid typing to biotyping and antibiotyping in the characterization of outbreaks by Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Maria Cristina Bronharo Tognim

    1999-01-01

    Full Text Available During an outbreak at an University Hospital, from April to September, in 1994, sixteen strains of Acinetobacter baumannii were isolated from patients and one strain from an enteral solution. We afterwards analyzed the outbreak by means of plasmid typing, antibiotic resistance typing and biotyping. Two main plasmid profiles were identified. Twelve strains belonged to biotype 2, and five to biotype 19. Susceptibility to amikacin and to carbenicillin allowed classification of the strains into two groups. The results show that association of those three typing methods allowed the differentiation of what was at first considered as a single outbreak into two apparently unrelated outbreaks.Durante um surto ocorrido de abril a setembro de 1994 em um Hospital Universitário, dezesseis cepas de Acinetobacter baumannii foram isoladas de pacientes e uma de solução enteral. Nós posteriormente analizamos as cepas isoladas durante o surto pelos seguintes métodos de tipagem : perfil de DNA plasmidial, perfil de antibiograma e biotipagem. Dois padrões de tipagem foram identificados pela análise do perfil plasmidial. Doze cepas foram caracterizadas como sendo do biotipo 2, e cinco do biotipo 19. O padrão de sensibilidade a amicacina e a carbenicilina possibilitou a classificação das cepas em dois grupos. Os resultados demonstraram que estes três métodos de tipagem associados possibilitaram a diferenciação do que primeiramente foi considerado como um único surto, em dois surtos aparentemente não relacionados.

  7. Clinically Relevant Growth Conditions Alter Acinetobacter baumannii Antibiotic Susceptibility and Promote Identification of Novel Antibacterial Agents.

    Directory of Open Access Journals (Sweden)

    Jennifer M Colquhoun

    Full Text Available Biological processes that govern bacterial proliferation and survival in the host-environment(s are likely to be vastly different from those that are required for viability in nutrient-rich laboratory media. Consequently, growth-based antimicrobial screens performed in conditions modeling aspects of bacterial disease states have the potential to identify new classes of antimicrobials that would be missed by screens performed in conventional laboratory media. Accordingly, we performed screens of the Selleck library of 853 FDA approved drugs for agents that exhibit antimicrobial activity toward the Gram-negative bacterial pathogen Acinetobacter baumannii during growth in human serum, lung surfactant, and/or the organism in the biofilm state and compared those results to that of conventional laboratory medium. Results revealed that a total of 90 compounds representing 73 antibiotics and 17 agents that were developed for alternative therapeutic indications displayed antimicrobial properties toward the test strain in at least one screening condition. Of the active library antibiotics only four agents, rifampin, rifaximin, ciprofloxacin and tetracycline, exhibited antimicrobial activity toward the organism during all screening conditions, whereas the remainder were inactive in ≥ 1 condition; 56 antibiotics were inactive during serum growth, 25 and 38 were inactive toward lung surfactant grown and biofilm-associated cells, respectively, suggesting that subsets of antibiotics may outperform others in differing infection settings. Moreover, 9 antibiotics that are predominantly used for the treatment Gram-positive pathogens and 10 non-antibiotics lacked detectable antimicrobial activity toward A. baumannii grown in conventional medium but were active during ≥ 1 alternative growth condition(s. Such agents may represent promising anti-Acinetobacter agents that would have likely been overlooked by antimicrobial whole cell screening assays performed in

  8. Prevalence and analysis of microbiological factors associated with phenotypic heterogeneous resistance to carbapenems in Acinetobacter baumannii.

    Science.gov (United States)

    Fernández Cuenca, Felipe; Sánchez, M del Carmen Gómez; Caballero-Moyano, Francisco Javier; Vila, Jordi; Martínez-Martínez, Luis; Bou, Germán; Baño, Jesús Rodríguez; Pascual, Alvaro

    2012-06-01

    The objectives of this study were to determine the prevalence of Acinetobacter baumannii with phenotypic heterogeneous resistance (PHR) to carbapenems (colonies inside the halo of inhibition) and to analyse its association with several microbiological variables. Acinetobacter baumannii isolates collected in Spain were used to analyse: (i) minimum inhibitory concentrations (MICs) of carbapenems; (ii) heteroresistance to carbapenems; (iii) genes encoding β-lactamases (bla genes); (iv) insertion sequences; and (v) inactivation of genes encoding porins (CarO, OprD and Omp33-36) and genes associated with the AdeABC efflux system (adeB, adeR and adeS). Polymerase chain reaction (PCR) amplification was used for gene detection. The rate of PHR was 20% to imipenem and 24% to meropenem. Susceptibility to imipenem was observed in 39% of PHR isolates. MICs of carbapenems for colonies were similar (± 1 log(2) dilution) to those of their parental isolates. These colonies growing inside the inhibition halo also reproduced the PHR to carbapenems. Differences observed between PHR isolates and non-PHR isolates were: bla(OXA-58-like), 57% vs. 0%; oprD-like, 96% vs. 56%; adeB, 89% vs. 94%; adeR, 82% vs. 94%; adeS, 82% vs. 94%; ISAba2, 61% vs. 31%; and ISAba3, 57% vs. 0%. No interruption of genes encoding porins or the efflux-related genes (adeB, adeR and adeS) was observed. In conclusion, A. baumannii strains with PHR to carbapenems are widespread in Spain. This phenotype is present in carbapenem-susceptible isolates as well as those that are not susceptible to carbapenems. Heteroresistance cannot explain the PHR to carbapenems, which appears to relate more to persistence or tolerance to carbapenems. bla(OXA-58-like), bla(OXA-51-like), ISAba2 and ISAba3 are associated with PHR to carbapenems. Inactivation of genes encoding porins or genes related to AdeABC is infrequent.

  9. Variation in the complex carbohydrate biosynthesis loci of Acinetobacter baumannii genomes.

    Directory of Open Access Journals (Sweden)

    Johanna J Kenyon

    Full Text Available Extracellular polysaccharides are major immunogenic components of the bacterial cell envelope. However, little is known about their biosynthesis in the genus Acinetobacter, which includes A. baumannii, an important nosocomial pathogen. Whether Acinetobacter sp. produce a capsule or a lipopolysaccharide carrying an O antigen or both is not resolved. To explore these issues, genes involved in the synthesis of complex polysaccharides were located in 10 complete A. baumannii genome sequences, and the function of each of their products was predicted via comparison to enzymes with a known function. The absence of a gene encoding a WaaL ligase, required to link the carbohydrate polymer to the lipid A-core oligosaccharide (lipooligosaccharide forming lipopolysaccharide, suggests that only a capsule is produced. Nine distinct arrangements of a large capsule biosynthesis locus, designated KL1 to KL9, were found in the genomes. Three forms of a second, smaller variable locus, likely to be required for synthesis of the outer core of the lipid A-core moiety, were designated OCL1 to OCL3 and also annotated. Each K locus includes genes for capsule export as well as genes for synthesis of activated sugar precursors, and for glycosyltransfer, glycan modification and oligosaccharide repeat-unit processing. The K loci all include the export genes at one end and genes for synthesis of common sugar precursors at the other, with a highly variable region that includes the remaining genes in between. Five different capsule loci, KL2, KL6, KL7, KL8 and KL9 were detected in multiply antibiotic resistant isolates belonging to global clone 2, and two other loci, KL1 and KL4, in global clone 1. This indicates that this region is being substituted repeatedly in multiply antibiotic resistant isolates from these clones.

  10. Structural and bioinformatic characterization of an Acinetobacter baumannii type II carrier protein

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. Leigh; Gulick, Andrew M., E-mail: gulick@hwi.buffalo.edu [University at Buffalo, Buffalo, NY 14203 (United States)

    2014-06-01

    The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented. Microorganisms produce a variety of natural products via secondary metabolic biosynthetic pathways. Two of these types of synthetic systems, the nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), use large modular enzymes containing multiple catalytic domains in a single protein. These multidomain enzymes use an integrated carrier protein domain to transport the growing, covalently bound natural product to the neighboring catalytic domains for each step in the synthesis. Interestingly, some PKS and NRPS clusters contain free-standing domains that interact intermolecularly with other proteins. Being expressed outside the architecture of a multi-domain protein, these so-called type II proteins present challenges to understand the precise role they play. Additional structures of individual and multi-domain components of the NRPS enzymes will therefore provide a better understanding of the features that govern the domain interactions in these interesting enzyme systems. The high-resolution crystal structure of a free-standing carrier protein from Acinetobacter baumannii that belongs to a larger NRPS-containing operon, encoded by the ABBFA-003406–ABBFA-003399 genes of A. baumannii strain AB307-0294, that has been implicated in A. baumannii motility, quorum sensing and biofilm formation, is presented here. Comparison with the closest structural homologs of other carrier proteins identifies the requirements for a conserved glycine residue and additional important sequence and structural requirements within the regions that interact with partner proteins.

  11. Computational gene network study on antibiotic resistance genes of Acinetobacter baumannii.

    Science.gov (United States)

    Anitha, P; Anbarasu, Anand; Ramaiah, Sudha

    2014-05-01

    Multi Drug Resistance (MDR) in Acinetobacter baumannii is one of the major threats for emerging nosocomial infections in hospital environment. Multidrug-resistance in A. baumannii may be due to the implementation of multi-combination resistance mechanisms such as β-lactamase synthesis, Penicillin-Binding Proteins (PBPs) changes, alteration in porin proteins and in efflux pumps against various existing classes of antibiotics. Multiple antibiotic resistance genes are involved in MDR. These resistance genes are transferred through plasmids, which are responsible for the dissemination of antibiotic resistance among Acinetobacter spp. In addition, these resistance genes may also have a tendency to interact with each other or with their gene products. Therefore, it becomes necessary to understand the impact of these interactions in antibiotic resistance mechanism. Hence, our study focuses on protein and gene network analysis on various resistance genes, to elucidate the role of the interacting proteins and to study their functional contribution towards antibiotic resistance. From the search tool for the retrieval of interacting gene/protein (STRING), a total of 168 functional partners for 15 resistance genes were extracted based on the confidence scoring system. The network study was then followed up with functional clustering of associated partners using molecular complex detection (MCODE). Later, we selected eight efficient clusters based on score. Interestingly, the associated protein we identified from the network possessed greater functional similarity with known resistance genes. This network-based approach on resistance genes of A. baumannii could help in identifying new genes/proteins and provide clues on their association in antibiotic resistance.

  12. Infecção cutânea rara por Acinetobacter baumannii em imunocompetente: relato de um caso Rare cutaneous infection by Acinetobacter baumannii in an immunocompetent patient: a case report

    Directory of Open Access Journals (Sweden)

    Pablo Vitoriano Cirino

    2008-08-01

    Full Text Available O Acinetobacter baumanni é patógeno oportunista antigamente considerado de baixa virulência. Atualmente está envolvido em processos infecciosos que acometem pacientes imunocomprometidos,grandes queimados e pacientes em unidades de terapia intensiva que fazem uso de ventilação mecânica. Esse relato de caso chama atenção para infecção cutânea rara por essa bactéria em paciente imunocompetente.Acinetobacter baumannii is an oportunistic pathogen that used to be considered as having low virulence; however, it is currently known to be involved in infectious processes in patients with immunosuppression, large burns and those under mechanical ventilation in intensive care units. This case report emphasizes the possibility of cutaneous infection by A. baumanni in immunocompetent patients.

  13. Resistência a β-lactâmicos em Acinetobacter spp isolados de efluente hospitalar no sul do Brasil Resistance to β-lactams among Acinetobacter spp isolated from hospital sewage in southern Brazil

    Directory of Open Access Journals (Sweden)

    Carolina de Souza Gusatti

    2009-04-01

    Full Text Available Acinetobacter spp é um importante patógeno causador de infecções nosocomiais que acomete pacientes imunocomprometidos e capaz de adquirir resistência a antimicrobianos com facilidade. Os esgotos hospitalares são importantes disseminadores de genes de resistência a antimicrobianos para a microbiota ambiental. Neste contexto, 30 cepas de Acinetobacter spp provenientes de efluente de um hospital em Porto Alegre, RS, foram analisados quanto ao perfil de susceptibilidade a β-lactamases, quinolonas e aminoglicosídeos através de antibiograma e testes de triagem para metalo beta-lactamases e β-lactamases de espectro estendido. O perfil encontrado revela cepas multi-resistentes e que mecanismos de resistência como a produção de β-lactamases de espectro estendido e bombas de efluxo podem estar presentes nesses isolados.Acinetobacter spp is an important pathogen that is responsible for nosocomial infections affecting immunocompromised patients, and it can easily acquire resistance to antimicrobial agents. Hospital sewage is an important means for disseminating genes for resistance to antimicrobial agents, to the microbiota of the environment. Within this context, 30 strains of Acinetobacter spp from the sewage of a hospital in Porto Alegre, Rio Grande do Sul, were analyzed regarding their profile of susceptibility to β-lactams, quinolones and aminoglycosides, by means of an antibiogram and tests to screen for metallo-β-lactamases and extended-spectrum β-lactamases. The profile obtained revealed the presence of multidrug-resistant strains and showed that resistance mechanisms such as the production of extended-spectrum β-lactamases and efflux pumps may be present in these strains.

  14. Study on biological phosphorus removal process by Acinetobacter lwoffi: possibility to by-pass the anaerobic phase

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa (Italy)

    1998-03-01

    An Acinetobacter lwoffi culture has been submitted to anaerobic/aerobic conditions in a Sequencing Batch Reactor (SBR) in order to study the ability of this strain in biological phosphorus removal process. Even by feeding a pure sodium acetate substrate, no phosphorus release has been detected during anaerobiosis, while phosphorus uptake beyond metabolic needs has been recorded during the aerobic phase; the anaerobic phase seems to have no influence on the enhanced biological phosphorus removal mechanisms. Hence aerobic batch tests have been carried out in order to verify the ability of Acinetobacter lwoffi to remove phosphorus by ``luxury uptake`` and ``overplus accumulation`` without anaerobic stress. Obtained results revealed a phosphorus removal efficiency of 75-80%. (orig.) With 5 figs., 3 tabs., 18 refs.

  15. Development of a real-time PCR assay for the rapid detection of Acinetobacter baumannii from whole blood samples.

    Science.gov (United States)

    De Gregorio, Eliana; Roscetto, Emanuela; Iula, Vita Dora; Martinucci, Marianna; Zarrilli, Raffaele; Di Nocera, Pier Paolo; Catania, Maria Rosaria

    2015-04-01

    Acinetobacter baumannii is a multidrug-resistant pathogen associated with severe infections in hospitalized patients, including pneumonia, urinary and bloodstream infections. Rapid detection of A. baumannii infection is crucial for timely treatment of septicemic patients. The aim of the present study was to develop a specific marker for a quantitative polymerase chain reaction (PCR) assay for the detection of A. baumannii. The target gene chosen is the biofilm-associated protein (bap) gene, encoding a cell surface protein involved in biofilm formation. The assay is specific for A. baumannii, allowing its discrimination from different species of Acinetobacter and other clinically relevant bacterial pathogens. The assay is able to detect one genomic copy of A. baumannii, corresponding to 4 fg of purified DNA, and 20 colony-forming units/ml using DNA extracted from spiked whole blood samples.

  16. Differential roles of antimicrobials in the acquisition of drug resistance through activation of the SOS response in Acinetobacter baumannii.

    Science.gov (United States)

    Jara, Luis M; Cortés, Pilar; Bou, Germán; Barbé, Jordi; Aranda, Jesús

    2015-07-01

    The effect of antimicrobials on SOS-mediated mutagenesis induction depends on the bacterial species and the antimicrobial group. In this work, we studied the effect of different families of antimicrobial agents used in clinical therapy against Acinetobacter baumannii in the induction of mutagenesis in this multiresistant Gram-negative pathogen. The data showed that ciprofloxacin and tetracycline induce SOS-mediated mutagenesis, whereas colistin and meropenem, which are extensively used in clinical therapy, do not.

  17. Família Enterobacteriaceae, Acinetobacter baumannii e Pseudomonados na microbiota bucal de pacientes mantidos em unidades de terapia intensiva

    OpenAIRE

    GAETTI-JARDIM JÚNIOR Elerson; Okamoto, Ana Claudia [UNESP; Meca,Lívia Buzati; Silva, Paloma Pereira da [UNESP; Bombarda, Fábio; Schweitzer, Christiane Marie [UNESP

    2014-01-01

    Enteric organisms, pseudomonads and other opportunistic microorganisms in the oral microbiota have been linked to serious infections in patients hospitalized in intensive care units (ICU). The present study evaluated the presence of family Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii in the mouth of patients in ICU, correlating it with oral and systemic conditions. Data on health, socioeconomic status, medication use, drug addiction, medical and family histories of ...

  18. Detection of OXA-Type Carbapenemase Genes in Acinetobacter baumannii Isolates from Nosocomial Infections in Isfahan Hospitals, Iran

    OpenAIRE

    2016-01-01

    "> Background: Acinetobacter baumannii as one of the causes of nosocomial infections has becomeresistant to almost all antimicrobial agents. The emergence of resistance to carbapenems, one ofthe last drugs on the shelf, is the major concern about A. baumannii antimicrobial resistance.Resistance to carbapenems is mediated by production of class B and D carbapenemases. The aimof this study was to detect the resistance genes including blaOXA-23, 24, 51, and 58 in A. baumanniiisolates from nos...

  19. Emergence and Spread of Plasmid-Borne tet(B)::ISCR2 in Minocycline-Resistant Acinetobacter baumannii Isolates

    OpenAIRE

    Vilacoba, Elisabet; Almuzara, Marisa; Gulone, Lucía; Traglia, German Matias; Figueroa, Silvia A.; Sly, Gabriela Edith; Fernandez, Analia; Centron, Daniela; Ramirez, Maria Soledad

    2013-01-01

    Resistance to minocycline has emerged in multidrug-resistant Acinetobacter baumannii isolates from Buenos Aires Hospitals. Few reports about the description and dispersion of tet genes were published in this species. We observed the presence of tet(B) in all minocycline resistant isolates. This gene was found associated to the ISCR2 mobile element, which could in part explain its dispersion. Fil: Vilacoba, Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Co...

  20. Update on Acinetobacter species: mechanisms of antimicrobial resistance and contemporary in vitro activity of minocycline and other treatment options.

    Science.gov (United States)

    Castanheira, Mariana; Mendes, Rodrigo E; Jones, Ronald N

    2014-12-01

    Among Acinetobacter species, A. baumannii and other closely related species are commonly implicated in nosocomial infections. These organisms are usually multidrug resistant (MDR), and therapeutic options to treat A. baumannii infections are very limited. Clinicians have been resorting to older antimicrobial agents to treat infections caused by MDR A. baumannii, and some of these agents have documented toxicity and/or are not optimized for the infection type to be treated. Recent clinical experience supported by antimicrobial susceptibility data suggests that minocycline has greater activity than other tetracyclines and glycylcyclines against various MDR pathogens that have limited therapeutic options available, including Acinetobacter species. An intravenous formulation of minocycline has recently become available for clinical use, and in contrast to most older tetracyclines, minocycline has high activity against Acinetobacter species. In this report, we summarized some of the characteristics of the tetracycline class, and quantified the minocycline activity against contemporary (2007-2011) isolates and its potential therapeutic role against a collection of 5477 A. baumannii and other relevant gram-negative organisms when compared directly with tetracycline, doxycycline, and other broad-spectrum antimicrobial agents. Acinetobacter baumannii strains were highly resistant to all agents tested, with the exception of minocycline (79.1% susceptible) and colistin (98.8% susceptible). Minocycline (minimum inhibitory concentration that inhibits 50% and 90% of the isolates [MIC(50/90)]: 1/8 µg/mL) displayed greater activity than doxycycline (MIC(50/90): 2/>8 µg/mL) and tetracycline hydrochloride (HCL) (only 30.2% susceptible) against A. baumannii isolates, and was significantly more active than other tetracyclines against Burkholderia cepacia, Escherichia coli, Serratia marcescens, and Stenotrophomonas maltophilia isolates. In vitro susceptibility testing using

  1. Usefulness of phenotypic and genotypic methods for metallo-beta-lactamases detection in carbapenem-resistant Acinetobacter baumannii strains

    OpenAIRE

    2013-01-01

    Background Acinetobacter baumannii is an opportunistic microorganism with an increasing role in nosocomial outbreaks. For the last 2 decades, a growing number of carbapenem-resistant A. baumannii strains have been identified, including the metallo-beta-lactamases (MBLs) producers. The study aimed to investigate the genetic relatedness of, and MBLs production among, a collection of A. baumannii isolates from Poland. Material/Methods This study involved 78 clinical isolates of carbapenem-resist...

  2. OXA-207, a novel OXA-24 variant with reduced catalytic efficiency against carbapenems in Acinetobacter pittii from Spain.

    Science.gov (United States)

    Cayô, Rodrigo; Merino, María; Ruiz Del Castillo, Belén; Cano, María Eliecer; Calvo, Jorge; Bou, Germán; Martínez-Martínez, Luis

    2014-08-01

    A carbapenem-resistant Acinetobacter pittii strain carrying an OXA-24-like enzyme was isolated in northern Spain in 2008. Sequence analysis confirmed the presence of the novel bla(OXA-207) gene flanked by the site-specific XerC/XerD-like recombination binding sites and showing a unique Gly222Val substitution compared to OXA-24. Cloning and kinetic analysis showed that OXA-207 presents a reduction in the catalytic efficiency against carbapenems and a noticeable increase for oxacillin.

  3. Biodegradation of Medium Chain Hydrocarbons by Acinetobacter venetianus 2AW Immobilized to Hair-Based Adsorbent Mats (Postprint)

    Science.gov (United States)

    2010-09-01

    McDonagh M. Field evaluations of marine oil spill bioremediation . Microbiol Rev. 1996;60:342–365. 12. Reisfeld A, Rosenberg E, Gutnick D. Microbial...adsorbent, for in situ degradation of hydrocarbons, has practical application in the bioremediation of oil in water emulsions. acinetobacter...the rest comes from human activ- ities.1 Oil spills that occur as a result of accidents or envi- ronmental disturbances create significant economic

  4. Rapid detection of blaOXA in carbapenem-susceptible Acinetobacter radioresistens bacteremia leading to unnecessary antimicrobial administration.

    Science.gov (United States)

    Brady, Adam C; Lewis, James S; Pfeiffer, Christopher D

    2016-08-01

    Rapid molecular techniques to identify resistant pathogens are revolutionizing antibiotic stewardship; however, it is important to recognize the limitations of these techniques. Herein we describe two cases of bacteremia that were both initially identified by genotypic testing as carbapenem-resistant Acinetobacter spp. and subsequently identified phenotypically as carbapenem-susceptible A. radioresistens. The genotypic results prompted unnecessary broad-spectrum antibiotic use and infection control concerns.

  5. Innate immune responses to systemic Acinetobacter baumannii infection in mice: neutrophils, but not interleukin-17, mediate host resistance.

    Science.gov (United States)

    Breslow, Jessica M; Meissler, Joseph J; Hartzell, Rebecca R; Spence, Phillip B; Truant, Allan; Gaughan, John; Eisenstein, Toby K

    2011-08-01

    Acinetobacter baumannii is a nosocomial pathogen with a high prevalence of multiple-drug-resistant strains, causing pneumonia and sepsis. The current studies further develop a systemic mouse model of this infection and characterize selected innate immune responses to the organism. Five clinical isolates, with various degrees of antibiotic resistance, were assessed for virulence in two mouse strains, and between male and female mice, using intraperitoneal infection. A nearly 1,000-fold difference in virulence was found between bacterial strains, but no significant differences between sexes or mouse strains were observed. It was found that microbes disseminated rapidly from the peritoneal cavity to the lung and spleen, where they replicated. A persistent septic state was observed. The infection progressed rapidly, with mortality between 36 and 48 h. Depletion of neutrophils with antibody to Ly-6G decreased mean time to death and increased mortality. Interleukin-17 (IL-17) promotes the response of neutrophils by inducing production of the chemokine keratinocyte-derived chemoattractant (KC/CXCL1), the mouse homolog of human IL-8. Acinetobacter infection resulted in biphasic increases in both IL-17 and KC/CXCL1. Depletion of neither IL-17 nor KC/CXCL1, using specific antibodies, resulted in a difference in bacterial burdens in organs of infected mice at 10 h postinfection. Comparison of bacterial burdens between IL-17a(-/-) and wild-type mice confirmed that the absence of this cytokine did not sensitize mice to Acinetobacter infection. These studies definitely demonstrate the importance of neutrophils in resistance to systemic Acinetobacter infection. However, neither IL-17 nor KC/CXCL1 alone is required for effective host defense to systemic infection with this organism.

  6. Identification and characterisation of the putative phage-related endolysins through full genome sequence analysis in Acinetobacter baumannii ATCC 17978.

    Science.gov (United States)

    Lai, Meng-Jiun; Soo, Po-Chi; Lin, Nien-Tsung; Hu, Anren; Chen, You-Jie; Chen, Li-Kuang; Chang, Kai-Chih

    2013-08-01

    Acinetobacter baumannii has recently emerged as a major cause of healthcare-associated infections owing to an increase in its antimicrobial resistance to virtually all available drugs. The ability of endolysins (lysozymes) to digest cell walls when applied exogenously to bacterial cells has enabled their use as novel antibacterials. In order to utilise endolysins as a therapeutic alternative to antibiotics, we surveyed the genome sequence of A. baumannii ATCC 17978 and successfully identified two phage-related endolysin genes, A1S_1600 and A1S_2016 (termed lysAB3 and lysAB4, respectively). Following cloning and expression/purification, various antibacterial activities of these two phage-related endolysins were determined in vitro. Zymographic assays showed that only purified LysAB3 could lyse the peptidoglycan of the A. baumannii cell wall. When applied exogenously, both LysAB3 and LysAB4 were active against most Acinetobacter spp. tested but had virtually no activity against other non-Acinetobacter spp. Scanning electron microscopy revealed that exposure to 100μg/mL LysAB3 and LysAB4 for up to 60min caused a remarkable modification of the cell shape of A. baumannii. These results indicate that the genes encoding phage-related endolysins can be readily isolated from the bacterial genome and have potential for the development of novel antimicrobial agents.

  7. Optimization of fermentation medium for the production of atrazine degrading strain Acinetobacter sp. DNS(32) by statistical analysis system.

    Science.gov (United States)

    Zhang, Ying; Wang, Yang; Wang, Zhi-Gang; Wang, Xi; Guo, Huo-Sheng; Meng, Dong-Fang; Wong, Po-Keung

    2012-01-01

    Statistical experimental designs provided by statistical analysis system (SAS) software were applied to optimize the fermentation medium composition for the production of atrazine-degrading Acinetobacter sp. DNS(32) in shake-flask cultures. A "Plackett-Burman Design" was employed to evaluate the effects of different components in the medium. The concentrations of corn flour, soybean flour, and K(2)HPO(4) were found to significantly influence Acinetobacter sp. DNS(32) production. The steepest ascent method was employed to determine the optimal regions of these three significant factors. Then, these three factors were optimized using central composite design of "response surface methodology." The optimized fermentation medium composition was composed as follows (g/L): corn flour 39.49, soybean flour 25.64, CaCO(3) 3, K(2)HPO(4) 3.27, MgSO(4)·7H(2)O 0.2, and NaCl 0.2. The predicted and verifiable values in the medium with optimized concentration of components in shake flasks experiments were 7.079 × 10(8) CFU/mL and 7.194 × 10(8) CFU/mL, respectively. The validated model can precisely predict the growth of atrazine-degraing bacterium, Acinetobacter sp. DNS(32).

  8. Medically Relevant Acinetobacter Species Require a Type II Secretion System and Specific Membrane-Associated Chaperones for the Export of Multiple Substrates and Full Virulence.

    Science.gov (United States)

    Harding, Christian M; Kinsella, Rachel L; Palmer, Lauren D; Skaar, Eric P; Feldman, Mario F

    2016-01-01

    Acinetobacter baumannii, A. nosocomialis, and A. pittii have recently emerged as opportunistic human pathogens capable of causing severe human disease; however, the molecular mechanisms employed by Acinetobacter to cause disease remain poorly understood. Many pathogenic members of the genus Acinetobacter contain genes predicted to encode proteins required for the biogenesis of a type II secretion system (T2SS), which have been shown to mediate virulence in many Gram-negative organisms. Here we demonstrate that Acinetobacter nosocomialis strain M2 produces a functional T2SS, which is required for full virulence in both the Galleria mellonella and murine pulmonary infection models. Importantly, this is the first bona fide secretion system shown to be required for virulence in Acinetobacter. Using bioinformatics, proteomics, and mutational analyses, we show that Acinetobacter employs its T2SS to export multiple substrates, including the lipases LipA and LipH as well as the protease CpaA. Furthermore, the Acinetobacter T2SS, which is found scattered amongst five distinct loci, does not contain a dedicated pseudopilin peptidase, but instead relies on the type IV prepilin peptidase, reinforcing the common ancestry of these two systems. Lastly, two of the three secreted proteins characterized in this study require specific chaperones for secretion. These chaperones contain an N-terminal transmembrane domain, are encoded adjacently to their cognate effector, and their disruption abolishes type II secretion of their cognate effector. Bioinformatic analysis identified putative chaperones located adjacent to multiple previously known type II effectors from several Gram-negative bacteria, which suggests that T2SS chaperones constitute a separate class of membrane-associated chaperones mediating type II secretion.

  9. Antimicrobial susceptibility profiling and genomic diversity of Acinetobacter baumannii isolates: A study in western Iran.

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    Parviz Mohajeri

    2013-09-01

    Full Text Available Acinetobacter baumannii is an aerobic non-motile Gram-negative bacterial pathogen that is resistant to most antibiotics. Carbapenems are the most common antibiotics for the treatment of infections caused by this pathogen. Mechanisms of antibiotic-resistance in A. baumannii are mainly mediated by efflux pumps-lactamases. The aim of this study was to determine antibiotic susceptibility, the possibility of existence of OXAs genes and fingerprinting by Pulsed-Field Gel Electrophoresis (PFGE among clinical isolates of Acinetobacter collected from Kermanshah hospitals.One hundred and four isolates were collected from patients attending Imam Reza, Taleghani and Imam Khomeini hospitals of Kermanshah (Iran. Isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics was assessed with Kirby-Bauer disk diffusion method. PCR was performed for detection of bla OXA-23, bla OXA-24, bla OXA-51 and bla OXA-58 beta-lactamase genes. Clonal relatedness was estimated by PFGE (with the restriction enzyme Apa I and DNA patterns were analyzed by Gel compare II 6.5 software.All isolates showed high-level of resistance to imipenem, meropenem as well as to other antimicrobial agents, while no resistance to polymyxin B, colistin, tigecylcine and minocycline was observed. The bla OXA-23like and bla OXA-24 like were found among 77.9% and 19.2% of the isolates, respectively. All isolates were positive for bla OXA-51, but none produced any amplicon for bla OXA-58. PFGE genotype analysis suggested the existence of eight clones among the 104 strains [A (n = 35, B (n = 29, C (n = 19, D (n = 10, E (n = 4, F (n = 3, G (n = 3, H (n = 1]. Clone A was the dominant clone in hospital settings particularly infection wards so that the isolates in this group, compared to the other clones, showed higher levels of resistance to antibiotics.The bla OXA-51-like and bla OXA-23like were the predominant mechanisms of resistance to imipenem in A

  10. Paradoxical Effect of Polymyxin B: High Drug Exposure Amplifies Resistance in Acinetobacter baumannii

    Science.gov (United States)

    Landersdorfer, Cornelia B.; Lenhard, Justin R.; Cheah, Soon-Ee; Thamlikitkul, Visanu; Rao, Gauri G.; Holden, Patricia N.; Forrest, Alan; Bulitta, Jürgen B.; Nation, Roger L.; Li, Jian

    2016-01-01

    Administering polymyxin antibiotics in a traditional fashion may be ineffective against Gram-negative ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens. Here, we explored increasing the dose intensity of polymyxin B against two strains of Acinetobacter baumannii in the hollow-fiber infection model. The following dosage regimens were simulated for polymyxin B (t1/2 = 8 h): non-loading dose (1.43 mg/kg of body weight every 12 h [q12h]), loading dose (2.22 mg/kg q12h for 1 dose and then 1.43 mg/kg q12h), front-loading dose (3.33 mg/kg q12h for 1 dose followed by 1.43 mg/kg q12h), burst (5.53 mg/kg for 1 dose), and supraburst (18.4 mg/kg for 1 dose). Against both A. baumannii isolates, a rapid initial decline in the total population was observed within the first 6 h of polymyxin exposure, whereby greater polymyxin B exposure resulted in greater maximal killing of −1.25, −1.43, −2.84, −2.84, and −3.40 log10 CFU/ml within the first 6 h. Unexpectedly, we observed a paradoxical effect whereby higher polymyxin B exposures dramatically increased resistant subpopulations that grew on agar containing up to 10 mg/liter of polymyxin B over 336 h. High drug exposure also proliferated polymyxin-dependent growth. A cost-benefit pharmacokinetic/pharmacodynamic relationship between 24-h killing and 336-h resistance was explored. The intersecting point, where the benefit of bacterial killing was equal to the cost of resistance, was an fAUC0–24 (area under the concentration-time curve from 0 to 24 h for the free, unbound fraction of drug) of 38.5 mg · h/liter for polymyxin B. Increasing the dose intensity of polymyxin B resulted in amplification of resistance, highlighting the need to utilize polymyxins as part of a combination against high-bacterial-density A. baumannii infections. PMID:27067330

  11. 鲍曼不动杆菌医院感染现状研究%Current situation of nosocomial infection about Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    赖智双; 许能锋

    2010-01-01

    Acinetobacter baumannii exists widely in the environment.It is one of the most important nosocmial pathogens.The prevalence of Acinetobacter baumannii has generally increased worldwide in the last two decades.Nosoc-comiai Acinetobacter baumannii is frequently associated with respiratory tract infections.The main risk factors of Acineto-bacter baumannii infection are environmental objects,patients' age,long hospitalization time,serious primaty disease,invasive procedures and drug improper use.In the article,the detection rate of Acinetobacter baumannii,the location of infection and the risk factors are reviewed.%鲍曼不动杆菌广泛分布于自然环境,已成为最常见的医院感染致病菌之一,近十几年其检出率逐年上升,主要引起呼吸系统的感染.导致其感染发生的危险因素主要为环境因素、年龄因素、住院时间长、基础疾病重、侵入性操作及药物使用不当等.此文就鲍曼不动杆菌临床检出率、感染部位分布及感染危险因素进行综述.

  12. Prophage induction and differential RecA and UmuDAb transcriptome regulation in the DNA damage responses of Acinetobacter baumannii and Acinetobacter baylyi.

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    Janelle M Hare

    Full Text Available The SOS response to DNA damage that induces up to 10% of the prokaryotic genome requires RecA action to relieve LexA transcriptional repression. In Acinetobacter species, which lack LexA, the error-prone polymerase accessory UmuDAb is instead required for ddrR induction after DNA damage, suggesting it might be a LexA analog. RNA-Seq experiments defined the DNA damage transcriptome (mitomycin C-induced of wild type, recA and umuDAb mutant strains of both A. baylyi ADP1 and A. baumannii ATCC 17978. Of the typical SOS response genes, few were differentially regulated in these species; many were repressed or absent. A striking 38.4% of all ADP1 genes, and 11.4% of all 17978 genes, were repressed under these conditions. In A. baylyi ADP1, 66 genes (2.0% of the genome, including a CRISPR/Cas system, were DNA damage-induced, and belonged to four regulons defined by differential use of recA and umuDAb. In A. baumannii ATCC 17978, however, induction of 99% of the 152 mitomycin C-induced genes depended on recA, and only 28 of these genes required umuDAb for their induction. 90% of the induced A. baumannii genes were clustered in three prophage regions, and bacteriophage particles were observed after mitomycin C treatment. These prophages encoded esvI, esvK1, and esvK2, ethanol-stimulated virulence genes previously identified in a Caenorhabditis elegans model, as well as error-prone polymerase alleles. The induction of all 17978 error-prone polymerase alleles, whether prophage-encoded or not, was recA dependent, but only these DNA polymerase V-related genes were de-repressed in the umuDAb mutant in the absence of DNA damage. These results suggest that both species possess a robust and complex DNA damage response involving both recA-dependent and recA-independent regulons, and further demonstrates that although umuDAb has a specialized role in repressing error-prone polymerases, additional regulators likely participate in these species' transcriptional

  13. Protection against Acinetobacter baumannii infection via its functional deprivation of biofilm associated protein (Bap).

    Science.gov (United States)

    Fattahian, Yaser; Rasooli, Iraj; Mousavi Gargari, Seyed Latif; Rahbar, Mohammad Reza; Darvish Alipour Astaneh, Shakiba; Amani, Jafar

    2011-12-01

    Acinetobacter baumannii, a major nosocomial pathogen, has remarkable capacity to acquire antimicrobial resistance attributable to its biofilm formation ability. Biofilm associated protein (Bap), a specific cell surface protein, is directly involved in biofilm formation by A. baumannii and plays a major role in bacterial infectious processes. In the present study we cloned, expressed and purified a 371 amino acid subunit of Bap. Mice were immunized using recombinant Bap subunit. They were then challenged with A. baumannii to evaluate the immunogenicity and protectivity of Bap subunit. Humoral immune response to Bap was determined by ELISA. Injection of Bap subunit resulted in high antibody titers. Decrease in bacterial cell counts of the immunized mice was evident 18 h after challenge. Reaction of antibodies against Bap with several strains suggests that not only immunodominant regions of Bap in A. baumannii strains are conserved but also have the same epitope presenting pattern in different strains. Immunodominant region of Bap possesses target sites for a protective humoral immune response to A. baumannii. This seems to be a conserved region erecting efficacy of Bap as an appropriate vaccine candidate.

  14. Carbapenem resistance and mortality in patients with Acinetobacter baumannii infection: systematic review and meta-analysis.

    Science.gov (United States)

    Lemos, E V; de la Hoz, F P; Einarson, T R; McGhan, W F; Quevedo, E; Castañeda, C; Kawai, K

    2014-05-01

    Acinetobacter baumannii has emerged as a major cause of healthcare-associated infections. Controversy exists as to whether antimicrobial resistance increases the risk of mortality. We conducted a systematic review and meta-analysis to examine this association. We searched MEDLINE and EMBASE databases up to May 2013 to identify studies comparing mortality in patients with carbapenem-resistant A. baumannii (CRAB) vs. carbapenem-susceptible A. baumannii (CSAB). A random-effects model was used to pool Odds Ratios (OR). Heterogeneity was examined using I(2). We included 16 observational studies. There were 850 reported deaths (33%) among the 2546 patients. Patients with CRAB had a significantly higher risk of mortality than patients with CSAB in the pooled analysis of crude effect estimates (crude OR = 2.22; 95% CI = 1.66, 2.98), although substantial heterogeneity was evident (heterogeneity I(2) = 55%). The association remained significant in the pooled adjusted OR of 10 studies. Studies reported that patients with CRAB compared to patients with CSAB were more likely to have severe underlying illness and also to receive inappropriate empirical antimicrobial treatment, which increases the risk of mortality. Our study suggests that carbapenem resistance may increase the risk of mortality in patients with A. baumannii infection. However, cautious interpretation is required because of the residual confounding factors and inadequate sample size in most studies.

  15. The contribution of nutrient metal acquisition and metabolism to Acinetobacter baumannii survival within the host.

    Science.gov (United States)

    Mortensen, Brittany L; Skaar, Eric P

    2013-01-01

    Acinetobacter baumannii is a significant contributor to intensive care unit (ICU) mortality causing numerous types of infection in this susceptible ICU population, most notably ventilator-associated pneumonia. The substantial disease burden attributed to A. baumannii and the rapid acquisition of antibiotic resistance make this bacterium a serious health care threat. A. baumannii is equipped to tolerate the hostile host environment through modification of its metabolism and nutritional needs. Among these adaptations is the evolution of mechanisms to acquire nutrient metals that are sequestered by the host as a defense against infection. Although all bacteria require nutrient metals, there is diversity in the particular metal needs among species and within varying tissue types and bacterial lifecycles. A. baumannii is well-equipped with the metal homeostatic systems required for the colonization of a diverse array of tissues. Specifically, iron and zinc homeostasis is important for A. baumannii interactions with biotic surfaces and for growth within vertebrates. This review discusses what is currently known regarding the interaction of A. baumannii with vertebrate cells with a particular emphasis on the contributions of metal homeostasis systems. Overall, published research supports the utility of exploiting these systems as targets for the development of much-needed antimicrobials against this emerging infectious threat.

  16. Multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii: resistance mechanisms and implications for therapy.

    Science.gov (United States)

    Zavascki, Alexandre P; Carvalhaes, Cecília G; Picão, Renata C; Gales, Ana C

    2010-01-01

    Pseudomonas aeruginosa and Acinetobacter baumannii are major nosocomial pathogens worldwide. Both are intrinsically resistant to many drugs and are able to become resistant to virtually any antimicrobial agent. An increasing prevalence of infections caused by multidrug-resistant (MDR) isolates has been reported in many countries. The resistance mechanisms of P. aeruginosa and A. baumannii include the production of beta-lactamases, efflux pumps, and target-site or outer membrane modifications. Resistance to multiple drugs is usually the result of the combination of different mechanisms in a single isolate or the action of a single potent resistance mechanism. There are many challenges in the treatment of MDR P. aeruginosa and A. baumannii, especially considering the absence of new antimicrobials in the drug-development pipeline. In this review, we present the major resistance mechanisms of P. aeruginosa and A. baumannii, and discuss how they can affect antimicrobial therapy, considering recent clinical, microbiological, pharmacokinetic and pharmacodynamic findings of the main drugs used to treat MDR isolates.

  17. Epidemiology of Carbapenemase-Producing Enterobacteriaceae and Acinetobacter baumannii in Mediterranean Countries

    Directory of Open Access Journals (Sweden)

    Nassima Djahmi

    2014-01-01

    Full Text Available The emergence and global spread of carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii are of great concern to health services worldwide. These β-lactamases hydrolyse almost all β-lactams, are plasmid-encoded, and are easily transferable among bacterial species. They are mostly of the KPC, VIM, IMP, NDM, and OXA-48 types. Their current extensive spread worldwide in Enterobacteriaceae is an important source of concern. Infections caused by these bacteria have limited treatment options and have been associated with high mortality rates. Carbapenemase producers are mainly identified among Klebsiella pneumoniae, Escherichia coli, and A. baumannii and still mostly in hospital settings and rarely in the community. The Mediterranean region is of interest due to a great diversity and population mixing. The prevalence of carbapenemases is particularly high, with this area constituting one of the most important reservoirs. The types of carbapenemase vary among countries, partially depending on the population exchange relationship between the regions and the possible reservoirs of each carbapenemase. This review described the epidemiology of carbapenemases produced by enterobacteria and A. baumannii in this part of the world highlighting the worrisome situation and the need to screen and detect these enzymes to prevent and control their dissemination.

  18. Emergence of resistance to carbapenems in Acinetobacter baumannii in Europe: clinical impact and therapeutic options.

    Science.gov (United States)

    Kempf, Marie; Rolain, Jean-Marc

    2012-02-01

    Despite having a reputation of low virulence, Acinetobacter baumannii is an emerging multidrug-resistant (MDR) pathogen responsible for community- and hospital-acquired infections that are difficult to control and treat. Interest in this pathogen emerged about one decade ago because of its natural MDR phenotype, its capability of acquiring new mechanisms of resistance and the existence of nosocomial outbreaks. Recent advances in molecular biology, including full genome sequencing of several A. baumannii isolates, has led to the discovery of the extraordinary plasticity of their genomes, which is linked to their great propensity to adapt to any environment, including hospitals. In this context, as well as the increasing antimicrobial resistance amongst A. baumannii isolates to the last-line antibiotics carbapenems and colistin, therapeutic options are very limited or absent in some cases of infections with pandrug-resistant bacteria. However, a large proportion of patients may be colonised by such MDR bacteria without any sign of infection, leading to a recurrent question for clinicians as to whether antibiotic treatment should be given and will be effective in the presence of resistance mechanisms. The worldwide emergence of A. baumannii strains resistant to colistin is worrying and the increasing use of colistin to treat infections caused by MDR bacteria will inevitably increase the recovery rate of colistin-resistant isolates in the future. Current knowledge about A. baumannii, including biological and epidemiological aspects as well as resistance to antibiotics and antibiotic therapy, are reviewed in this article, in addition to therapeutic recommendations.

  19. Acinetobacter baumannii: human infections, factors contributing to pathogenesis and animal models.

    Science.gov (United States)

    McConnell, Michael J; Actis, Luis; Pachón, Jerónimo

    2013-03-01

    Acinetobacter baumannii has emerged as a medically important pathogen because of the increasing number of infections produced by this organism over the preceding three decades and the global spread of strains with resistance to multiple antibiotic classes. In spite of its clinical relevance, until recently, there have been few studies addressing the factors that contribute to the pathogenesis of this organism. The availability of complete genome sequences, molecular tools for manipulating the bacterial genome, and animal models of infection have begun to facilitate the identification of factors that play a role in A. baumannii persistence and infection. This review summarizes the characteristics of A. baumannii that contribute to its pathogenesis, with a focus on motility, adherence, biofilm formation, and iron acquisition. In addition, the virulence factors that have been identified to date, which include the outer membrane protein OmpA, phospholipases, membrane polysaccharide components, penicillin-binding proteins, and outer membrane vesicles, are discussed. Animal models systems that have been developed during the last 15 years for the study of A. baumannii infection are overviewed, and the recent use of these models to identify factors involved in virulence and pathogenesis is highlighted.

  20. Epidemiology of carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii in Mediterranean countries.

    Science.gov (United States)

    Djahmi, Nassima; Dunyach-Remy, Catherine; Pantel, Alix; Dekhil, Mazouz; Sotto, Albert; Lavigne, Jean-Philippe

    2014-01-01

    The emergence and global spread of carbapenemase-producing Enterobacteriaceae and Acinetobacter baumannii are of great concern to health services worldwide. These β-lactamases hydrolyse almost all β-lactams, are plasmid-encoded, and are easily transferable among bacterial species. They are mostly of the KPC, VIM, IMP, NDM, and OXA-48 types. Their current extensive spread worldwide in Enterobacteriaceae is an important source of concern. Infections caused by these bacteria have limited treatment options and have been associated with high mortality rates. Carbapenemase producers are mainly identified among Klebsiella pneumoniae, Escherichia coli, and A. baumannii and still mostly in hospital settings and rarely in the community. The Mediterranean region is of interest due to a great diversity and population mixing. The prevalence of carbapenemases is particularly high, with this area constituting one of the most important reservoirs. The types of carbapenemase vary among countries, partially depending on the population exchange relationship between the regions and the possible reservoirs of each carbapenemase. This review described the epidemiology of carbapenemases produced by enterobacteria and A. baumannii in this part of the world highlighting the worrisome situation and the need to screen and detect these enzymes to prevent and control their dissemination.

  1. Treatment options for carbapenem-resistant and extensively drug-resistant Acinetobacter baumannii infections.

    Science.gov (United States)

    Viehman, J Alexander; Nguyen, M Hong; Doi, Yohei

    2014-08-01

    Acinetobacter baumannii is a leading cause of healthcare-associated infections worldwide. Because of various intrinsic and acquired mechanisms of resistance, most β-lactam agents are not effective against many strains, and carbapenems have played an important role in therapy. Recent trends show many infections are caused by carbapenem-resistant or even extensively drug-resistant (XDR) strains, for which effective therapy is not well established. Evidence to date suggests that colistin constitutes the backbone of therapy, but the unique pharmacokinetic properties of colistin have led many to suggest the use of combination antimicrobial therapy. However, the combination of agents and dosing regimens that delivers the best clinical efficacy while minimizing toxicity is yet to be defined. Carbapenems, sulbactam, rifampin and tigecycline have been the most studied in the context of combination therapy. Most data regarding therapy for invasive, resistant A. baumannii infections come from uncontrolled case series and retrospective analyses, though some clinical trials have been completed and others are underway. Early institution of appropriate antimicrobial therapy is shown to consistently improve survival of patients with carbapenem-resistant and XDR A. baumannii infection, but the choice of empiric therapy in these infections remains an open question. This review summarizes the most current knowledge regarding the epidemiology, mechanisms of resistance, and treatment considerations of carbapenem-resistant and XDR A. baumannii.

  2. Carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii in the nosocomial setting in Latin America.

    Science.gov (United States)

    Labarca, Jaime A; Salles, Mauro José Costa; Seas, Carlos; Guzmán-Blanco, Manuel

    2016-01-01

    Increasing prevalence of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii strains in the nosocomial setting in Latin America represents an emerging challenge to public health, as the range of therapeutic agents active against these pathogens becomes increasingly constrained. We review published reports from 2002 to 2013, compiling data from throughout the region on prevalence, mechanisms of resistance and molecular epidemiology of carbapenem-resistant strains of P. aeruginosa and A. baumannii. We find rates of carbapenem resistance up to 66% for P. aeruginosa and as high as 90% for A. baumannii isolates across the different countries of Latin America, with the resistance rate of A. baumannii isolates greater than 50% in many countries. An outbreak of the SPM-1 carbapenemase is a chief cause of resistance in P. aeruginosa strains in Brazil. Elsewhere in Latin America, members of the VIM family are the most important carbapenemases among P. aeruginosa strains. Carbapenem resistance in A. baumannii in Latin America is predominantly due to the oxacillinases OXA-23, OXA-58 and (in Brazil) OXA-143. Susceptibility of P. aeruginosa and A. baumannii to colistin remains high, however, development of resistance has already been detected in some countries. Better epidemiological data are needed to design effective infection control interventions.

  3. Characteristics of multidrug-resistant Acinetobacter baumannii strains isolated in Geneva during colonization or infection.

    Science.gov (United States)

    Cherkaoui, Abdessalam; Emonet, Stéphane; Renzi, Gesuele; Schrenzel, Jacques

    2015-09-11

    This study determined the antibiotic susceptibility profile and genetic mechanisms of β-lactam resistance in 27 clinical strains of Acinetobacter baumannii isolated at the University Hospitals of Geneva, Switzerland. The antimicrobial susceptibility testing was performed using Etest and the disc diffusion method in accordance with CLSI guidelines. All of the strains were defined as multi-drug resistant (MDR) and were susceptible to colistin and moderately susceptible to tigecycline. Uniplex PCR assays were used to detect the following β-lactamase genes: four class D carbapenem-hydrolysing oxacillinases (blaOXA-51, blaOXA-23, blaOXA-24 and blaOXA-58), four class B metallo-β-lactamases genes (blaIMP, blaVIM, blaSPM and blaNDM) and two class A carbapenemases (blaKPC and blaGES). All of the strains were positive for blaOXA-51 (intrinsic resistance), 14/27 strains carried blaOXA-23, 2/27 strains carried a blaOXA-24-like gene, and 4/27 strains had a blaOXA-58 gene. blaGES-11 was found in three strains, and NDM-1-harbouring strains were identified in three patients. All of the A. baumannii isolates were typed by rep-PCR (DiversiLab) and excluded any clonality. Altogether, this analysis suggests a very high genetic diversity of imported MDR A. baumannii.

  4. Bacterial O-methylation of halogen-substituted phenols. [Rhodococcus; Acinetobacter

    Energy Technology Data Exchange (ETDEWEB)

    Allard, A.S.; Remberger, M.; Neilson, A.H.

    1987-04-01

    Two strains of bacteria capable of carrying out the O-methylation of phenolic compounds, one from the gram-positive genus Rhodococcus and one from the gram-negative genus Acinetobacter, were used to examine the O-methylation of phenols carrying fluoro-, chloro-, and bromo-substituents. Zero-order rates of O-methylation were calculated from data for the chloro- and bromophenols; there was no simple relationship between the rate of reaction and the structure of the substrates, and significant differences were observed in the responses of the two test organisms. For the gram-negative strain, the pattern of substitution was as important as the number of substituents. Hexachlorophene was resistant to O-methylation by both strains, and tetrabromobisphenol-A was O-methylated only by the gram-positive strain. It is suggested that in the natural environment, bacterial O-methylation of phenols carrying electron-attracting substituents might be a significant alternative to biodegradation.

  5. Survey of Phenantherene Biodegradation's Model inContaminated Soils by Acinetobacter SP

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    M Farzadkia

    2009-11-01

    Full Text Available Backgrounds and Objectives: Polycyclic aromatic hydrocarbons (PAHs are a group of hazardous pollutants which have carcinogenic and mutagenic properties and accumulated in environment by different actions, therefore treatment of them is important. Biological treatments are simple and cheep technologies. This technology was recommended as a cost- effective method for treatment of these pollutants. In order to investigate the trend of pollution reduction of petroleum hydrocarbons in bioremediation, the phenanthrene biodegradation's model in contaminated soils was studied."nMaterials and Methods: Firstly, PAHs capable degrading bacteria was isolated from petroleum contaminated soils and then their ability for biodegradation of phenanthrene was assessed in slurry phase. After that by using Acinetobacter which have the most potential of removing phenanthrene from soil, the biodegradation model was investigated in bench scale."nResults: Phenantherene removal efficiency was obtained 99.4% for 100 mg/kg and 96 % for 500 mg/kg concentrations in 33 and 60 days biodegradation period respectively. Phenantherene reduction rate varied from 2.99 to 8.86 and 1.4 to 11.09 mg/kg/day for 100 and 500 mg/kg concentrations, respectively."nConclusion: Rate of phenantherene removal is depended on primary concentration of contamination and by increasing of primary concentration, phenantherene removal rate was increased. Also removal efficiency followed zero and first order kinetic model with good correlation.

  6. Isolation and characterization of Acinetobacter baumannii recovered from Campylobacter selective medium.

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    Dinesh M Fernando

    2016-11-01

    Full Text Available Acinetobacter baumannii, a Gram-negative opportunistic pathogen, is known to cause multidrug resistant infections. This organism has primarily been isolated from clinical environments and its environmental reservoirs remain largely unknown. In the present study, we recovered seven isolates of A. baumannii growing under conditions selective for Campylobacter spp. (microaerophilic at 42 oC and in the presence of antibiotics from dairy cattle manure storage tank or surface water impacted by livestock effluents. Antibiotic susceptibility tests revealed that all of these isolates were less susceptible to at least two different clinically relevant antibiotics, compared to the type strain A. baumannii ATCC17978. Expression of resistance-nodulation-division efflux pumps, an important mechanism of intrinsic resistance in these organisms, was analyzed and adeB was found to be overexpressed in one and adeJ was overexpressed in three isolates. Comparison of these isolates using genomic DNA Macro-Restriction Fragment Pattern Analysis (MRFPA revealed relatively low relatedness among themselves or with some of the clinical isolates from previous studies. This study suggests that A. baumannii isolates are capable of growing under selective conditions for Campylobacter spp. and that this organism can be present in manure and water.

  7. Endogenous hydrogen peroxide increases biofilm formation by inducing exopolysaccharide production in Acinetobacter oleivorans DR1.

    Science.gov (United States)

    Jang, In-Ae; Kim, Jisun; Park, Woojun

    2016-02-17

    In this study, we investigated differentially expressed proteins in Acinetobacter oleivorans cells during planktonic and biofilm growth by using 2-dimensional gel electrophoresis combined with matrix-assisted laser desorption time-of-flight mass spectrometry. We focused on the role of oxidative stress resistance during biofilm formation using mutants defective in alkyl hydroperoxide reductase (AhpC) because its production in aged biofilms was enhanced compared to that in planktonic cells. Results obtained using an ahpC promoter-gfp reporter vector showed that aged biofilms expressed higher ahpC levels than planktonic cells at 48 h. However, at 24 h, ahpC expression was higher in planktonic cells than in biofilms. Deletion of ahpC led to a severe growth defect in rich media that was not observed in minimal media and promoted early biofilm formation through increased production of exopolysaccharide (EPS) and EPS gene expression. Increased endogenous H2O2 production in the ahpC mutant in rich media enhanced biofilm formation, and this enhancement was not observed in the presence of antioxidants. Exogenous addition of H2O2 promoted biofilm formation in wild type cells, which suggested that biofilm development is linked to defense against H2O2. Collectively, our data showed that EPS production caused by H2O2 stress enhances biofilm formation in A. oleivorans.

  8. Rhamnolipids produced by indigenous Acinetobacter junii from petroleum reservoir and its potential in enhanced oil recovery

    Directory of Open Access Journals (Sweden)

    Hao Dong

    2016-11-01

    Full Text Available Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS. The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9 and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

  9. Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

    Science.gov (United States)

    Dong, Hao; Xia, Wenjie; Dong, Honghong; She, Yuehui; Zhu, Panfeng; Liang, Kang; Zhang, Zhongzhi; Liang, Chuanfu; Song, Zhaozheng; Sun, Shanshan; Zhang, Guangqing

    2016-01-01

    Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9, and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

  10. Cloning, expression, crystallization and preliminary structural studies of dihydrodipicolinate reductase from Acinetobacter baumannii

    Science.gov (United States)

    Kaushik, Sanket; Singh, Avinash; Sinha, Mau; Kaur, Punit; Sharma, Sujata; Singh, Tej P.

    2013-01-01

    Acinetobacter baumannii is a virulent pathogenic bacterium that is resistant to most currently available antibiotics. Therefore, the design of drugs for the treatment of infections caused by A. baumannii is urgently required. Dihydrodipicolinate reductase (DHDPR) is an important enzyme which is involved in the biosynthetic pathway that leads to the production of l-lysine in bacteria. In order to design potent inhibitors against this enzyme, its detailed three-dimensional structure is required. DHDPR from A. baumannii (AbDHDPR) has been cloned, expressed, purified and crystallized. Here, the preliminary X-ray crystallographic data of AbDHDPR are reported. The crystals were grown using the hanging-drop vapour-diffusion method with PEG 3350 as the precipitating agent The crystals belonged to the orthorhombic space group P222, with unit-cell parameters a = 80.0, b = 100.8, c = 147.6 Å, and contained four molecules in the asymmetric unit. The complete structure determination of AbDHDPR is in progress. PMID:23722845

  11. Multidrug resistant Acinetobacter baumannii in veterinary medicine--emergence of an underestimated pathogen?

    Science.gov (United States)

    Müller, Stefanie; Janssen, Traute; Wieler, Lothar H

    2014-01-01

    The proportion of multidrug resistant bacteria causing infections in animals has continuously been increasing. While the relevance of ESBL (extended spectrum beta-lactamase)-producing Enterobacteriaceae spp. and MRSA (methicillin resistant Staphylococcus aureus) is unquestionable, knowledge about multidrug resistant Acinetobacter baumannii in veterinary medicine is scarce. This is a worrisome situation, as A. baumannii are isolated from veterinary clinical specimens with rising frequency. The remarkable ability of A. baumannii to develop multidrug resistance and the high risk of transmission are known in human medicine for years. Despite this, data regarding A. baumannii isolates of animal origin are missing. Due to the changing role of companion animals with closer contact between animal and owner, veterinary intensive care medicine is steadily developing. It can be assumed that the number of "high risk" patients with an enhanced risk for hospital acquired infections will be rising simultaneously. Thus, development and spread of multidrug resistant pathogens is envisioned to rise. It is possible, that A. baumannii will evolve into a veterinary nosocomial pathogen similar to ESBL-producing Enterobacteriaceae and MRSA. The lack of attention paid to A. baumannii in veterinary medicine is even more worrying, as first reports indicate a transmission between humans and animals. Essential questions regarding the role of livestock, especially as a potential source of multidrug resistant isolates, remain unanswered. This review summarizes the current knowledge on A. baumannii in veterinary medicine for the first time. It underlines the utmost significance of further investigations of A. baumannii animal isolates, particularly concerning epidemiology and resistance mechanisms.

  12. Molecular detection of aminoglycoside-modifying enzyme genes in Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Heidary, Mohsen; Salimi Chirani, Alireza; Khoshnood, Saeed; Eslami, Gita; Atyabi, Seyyed Mohammad; Nazem, Habibollah; Fazilati, Mohammad; Hashemi, Ali; Soleimani, Saleh

    2016-12-16

    Acinetobacter baumannii is a major opportunistic pathogen in healthcare settings worldwide. In Iran, there are only few reports on the prevalence of aminoglycoside resistance genes among A. baumannii isolates. The aim of this study was to investigate the existence of aminoglycoside-modifying enzyme (AME) genes from A. baumannii strains collected at a university teaching hospital in Iran. One hundred A. baumannii strains were collected between 2014 and 2015 from hospitalized patients at Loghman Hakim Hospital, Tehran, Iran. Antimicrobial susceptibility was determined by disk diffusion method according to the Clinical and Laboratory Standards Institute recommendations. The DNA was extracted using a kit obtained from Bioneer Co. (Korea) and was used as a template for polymerase chain reaction. The most active antimicrobial agent against these strains was colistin. The rate of extended-spectrum cephalosporin resistance was 97%. The aadA1, aadB, aac(6')-Ib, and aac(3)-IIa genes were found in 85%, 77%, 72%, and 68% of A. baumannii isolates, respectively. This study showed a high prevalence rate of AME genes in A. baumannii. This prevalence rate has explained that further aminoglycoside resistance genes may have role in the resistance of clinical isolates of A. baumannii. Therefore, control and treatment of serious infections caused by this opportunistic pathogen should be given more consideration.

  13. Multidrug Resistance of Acinetobacter Baumannii in Ladoke Akintola University Teaching Hospital, Osogbo, Nigeria

    Science.gov (United States)

    Odewale, G.; Adefioye, O. J.; Ojo, J.; Adewumi, F. A.; Olowe, O. A.

    2016-01-01

    Acinetobacter baumannii is a ubiquitous pathogen that has emerged as a major cause of healthcare-associated infections at Ladoke Akintola University Teaching Hospital. Isolates were assayed according to standard protocol. The isolates were subjected to molecular techniques to detect blaOXA, blaTEM, blaCTX-M, and blaSHV genes in strains of the A. baumannii isolates. The prevalence of A. baumannii was 8.5% and was most prevalent among patients in the age group 51–60 (36%); the male patients (63.6%) were more infected than their female counterparts. Patients (72.7%) in the intensive care unit (ICU) were most infected with this organism. The isolates showed 100% resistance to both amikacin and ciprofloxacin and 90.9% to both ceftriaxone and ceftazidime, while resistance to the other antibiotics used in this study were: piperacillin (81.8%), imipenem (72.7%), gentamycin (72.2%), and meropenem (63.6%). None of the isolates was, however, resistant to colistin. PCR results showed that blaOXA, blaTEM, and blaCTX-M genes were positive in some isolates, while blaSHV was not detected in any of the isolates. This study has revealed that the strains of A. baumannii isolated are multiple drug resistant. Regular monitoring, judicious prescription, and early detection of resistance to these antibiotics are, therefore, necessary to check further dissemination of the organism. PMID:27766173

  14. Differential Role of the T6SS in Acinetobacter baumannii Virulence

    Science.gov (United States)

    Foucault-Grunenwald, Marie-Laure; Borges, Vitor; Charpentier, Xavier; Limansky, Adriana S.; Gomes, João Paulo; Viale, Alejandro M.; Salcedo, Suzana P.

    2015-01-01

    Gram-negative bacteria, such as Acinetobacter baumannii, are an increasing burden in hospitals worldwide with an alarming spread of multi-drug resistant (MDR) strains. Herein, we compared a type strain (ATCC17978), a non-clinical isolate (DSM30011) and MDR strains of A. baumannii implicated in hospital outbreaks (Ab242, Ab244 and Ab825), revealing distinct patterns of type VI secretion system (T6SS) functionality. The T6SS genomic locus is present and was actively transcribed in all of the above strains. However, only the A. baumannii DSM30011 strain was capable of killing Escherichia coli in a T6SS-dependent manner, unlike the clinical isolates, which failed to display an active T6SS in vitro. In addition, DSM30011 was able to outcompete ATCC17978 as well as Pseudomonas aeruginosa and Klebsiella pneumoniae, bacterial pathogens relevant in mixed nosocomial infections. Finally, we found that the T6SS of DSM30011 is required for host colonization of the model organism Galleria mellonella suggesting that this system could play an important role in A. baumannii virulence in a strain-specific manner. PMID:26401654

  15. Prevalence and resistance ofAcinetobacter baumannii isolated at Hyatabad Medical Complex, Khyber Pakhtunkhwa, Pakistan

    Institute of Scientific and Technical Information of China (English)

    Said Hassan; Farhad Ali; Ibrar Alam; Rahmat Gul

    2016-01-01

    Objective:To assess the resistance against widely used antibiotics in case ofAcinetobacter baumannii (A. baumannii) infection. Methods:A total of 350 samples of pus, urine, swab and others from different patients were examined and the bacterial growth appeared in 50 samples. Each sample was inoculated on blood, MacConkey and cystine lactose electrolyte deficient agar. The antimicrobial susceptibility profile of the isolates was determined using agar plate method/disk-diffusion method (modified-Kirby Baur disc diffusion method). Results: In current study, a large number of isolates ofA. baumannii obtained from different specimens were resistant to avelox (56%), followed by tygacil (46%), augmentin (46%), cefspan (38%), cefixime (24%) and ampicillin (20%). However, the antibiogram ofA. baumannii also showed that most of the isolates (88%) were highly sensitive to cefalexin. Second maximum sensitivity ofA. baumanniiwas seen to amikacin (84%). The sensitivity of isolates against amikacin was followed by ticarcillin (80%). Meronem was found highly active against the tested isolates (78%). Sensitivity was observed for tienem (76%), sulzone (72%) followed by azactam (68%), cefobid (66%) to cefotaxime (66%) and ciproxin (62%). Conclusions:Results elucidate thatA. baumannii is a severe problem as it has become a highly resistant species in hospitalized patients and resistantA. baumannii infection turned out to have increased all-cause mortality.

  16. Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii in South America.

    Science.gov (United States)

    Rodríguez, Carlos Hernán; Balderrama Yarhui, Norah; Nastro, Marcela; Nuñez Quezada, Tamara; Castro Cañarte, Glenda; Magne Ventura, Raquel; Ugarte Cuba, Tayita; Valenzuela, Natalia; Roach, Freddy; Mota, María Inés; Burger, Noelia; Velázquez Aguayo, Gladys; Ortellado-Canese, Juana; Bruni, Geni; Pandolfo, Cecilia; Bastyas, Nadya; Famiglietti, Angela

    2016-10-01

    One hundred and twenty-six epidemiologically sequential, unrelated, carbapenem-resistant Acinetobacter baumannii isolates from nine hospitals in six countries of South America were collected between July 2013 and June 2014. Genes coding for Ambler class D and B carbapenemases were sought by PCR. All isolates were typed using the 3-locus sequence typing and blaOXA-51-like sequence-based typing techniques. The blaOXA-23 gene was recovered in all the participating hospitals and in all the isolates of seven of nine medical centres. The blaOXA-72 gene was only recovered in the two medical centres from Guayaquil city, Ecuador. Trilocus sequence typing revealed the presence of sequence groups SG2, SG4 and SG5. blaOXA-51-like sequence-based typing revealed the presence of blaOXA-132, blaOXA-65, blaOXA-69 and blaOXA-64. Our results showed that the population of carbapenem-resistant A. baumannii in South America was principally associated with ST79, ST25 and ST15 (92 %) and harboured the blaOXA-23 gene mainly. CC2 was not detected.

  17. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology

    Science.gov (United States)

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-01-01

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii (A. baumannii) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen. PMID:28230771

  18. Interaction of Acinetobacter baumannii 19606 and 1656-2 with Acanthamoeba castellanii.

    Science.gov (United States)

    Tamang, Migma Dorji; Kim, Shukho; Kim, Sung-Min; Kong, Hyun-Hee; Kim, Jungmin

    2011-10-01

    Acinetobacter baumannii is virtually avirulent for healthy people but maintains a high virulence among critically ill patients or immuno-compromised individuals. The ability of A. baumannii to adhere to cells and persist on surfaces as biofilms could be central to its pathogenicity. In the present study, we compared the virulence of the A. baumannii 1656-2 clinical strain, which is able to form a thick biofilm, with the virulence of the A. baumannii type strain (ATCC 19606(T)). Acanthamoeba castellanii, a single-celled organism, was used as the host model system to study the virulence of A. baumannii. Compared to A. baumannii ATCC 19606(T), A. baumannii 1656-2 exhibited a higher ability to adhere and invade A. castellanii cells and had a higher killing rate of A. castellanii cells. Furthermore, co-incubation of the amoeba cells and the cell-free supernatant of A. baumannii resulted in the cell death of the amoebae. Heat inactivation or proteinase K treatment of the supernatant did not eliminate its cytotoxicity, suggesting heat stable non-protein factors are responsible for its cytotoxicity to A. castellanii cells. In conclusion, this study for the first time has revealed the capacity of the A. baumannii strain and/or its metabolic products to induce cytotoxicity in A. castellanii cells.

  19. Detoxification of Indole by an Indole-Induced Flavoprotein Oxygenase from Acinetobacter baumannii.

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    Guang-Huey Lin

    Full Text Available Indole, a derivative of the amino acid tryptophan, is a toxic signaling molecule, which can inhibit bacterial growth. To overcome indole-induced toxicity, many bacteria have developed enzymatic defense systems to convert indole to non-toxic, water-insoluble indigo. We previously demonstrated that, like other aromatic compound-degrading bacteria, Acinetobacter baumannii can also convert indole to indigo. However, no work has been published investigating this mechanism. Here, we have shown that the growth of wild-type A. baumannii is severely inhibited in the presence of 3.5 mM indole. However, at lower concentrations, growth is stable, implying that the bacteria may be utilizing a survival mechanism to oxidize indole. To this end, we have identified a flavoprotein oxygenase encoded by the iifC gene of A. baumannii. Further, our results suggest that expressing this recombinant oxygenase protein in Escherichia coli can drive indole oxidation to indigo in vitro. Genome analysis shows that the iif operon is exclusively present in the genomes of A. baumannii and Pseudomonas syringae pv. actinidiae. Quantitative PCR and Western blot analysis also indicate that the iif operon is activated by indole through the AraC-like transcriptional regulator IifR. Taken together, these data suggest that this species of bacteria utilizes a novel indole-detoxification mechanism that is modulated by IifC, a protein that appears to be, at least to some extent, regulated by IifR.

  20. Nosocomial imipenem-resistant Acinetobacter baumannii infections: epidemiology and risk factors.

    Science.gov (United States)

    Dizbay, Murat; Tunccan, Ozlem Guzel; Sezer, Busra Ergut; Hizel, Kenan

    2010-10-01

    The incidence, clinical characteristics, risk factors, antimicrobial susceptibility, and outcomes of nosocomial imipenem-resistant A. baumannii (IRAB) infections during a 5-y period (2003-2007) were retrospectively analyzed. A total of 720 patients with 925 episodes of A. baumannii infection were included in the study. A. baumannii infections were seen mostly in intensive care units. The incidence was 6.2 per 1000 admissions. The most common infections were pneumonias and bloodstream infections. Imipenem resistance among Acinetobacter strains increased significantly each y of the study (from 43.3% to 72.9%). Mortality was related to the presence of imipenem resistance, stay in intensive care unit, female gender, old age, and pneumonia. Haemodialysis, malignancy, and mechanical ventilation were significant risk factors for IRAB infections. Imipenem resistance was higher in strains isolated from patients with pneumonia. IRAB strains showed higher resistance rates to other antibiotics than imipenem-susceptible strains. The most active antimicrobial agents against A. baumannii were cefoperazone-sulbactam and netilmicin. The incidence of A. baumannii infections and imipenem resistance increased during the study period. IRAB infections should be considered in patients on mechanical ventilation and haemodialysis and in patients with malignancies.

  1. Use of the accessory genome for characterization and typing of Acinetobacter baumannii.

    Science.gov (United States)

    Turton, Jane F; Baddal, Buket; Perry, Claire

    2011-04-01

    Outbreak strains of Acinetobacter baumannii are highly clonal, and cross-infection investigations can be difficult. We sought targets based on AbaR resistance islands and on other genes found in some, but not all, sequenced isolates of A. baumannii among a set of clinical isolates (n = 70) that included multiple representatives of a number of pulsed-field gel electrophoresis (PFGE)-defined types. These included representatives that varied in their profiles at two variable-number tandem repeat (VNTR) loci, which can provide discrimination within a PFGE cluster. Detection, or not, of each element sought provided some degree of discrimination among the set, with the presence or absence of genes coding for a phage terminase (ACICU_02185), a sialic acid synthase (ACICU_00080), a polysaccharide biosynthesis protein (AB57_0094), aphA1, bla(TEM), and integron-associated orfX (Kyoto Encyclopedia of Genes and Genomes [KEGG] no. K03830) proving the most helpful in discriminating between closely related isolates in our panel. The results support VNTR data in describing distinct populations of highly similar isolates. Such analysis, in combination with other typing methods, can inform epidemiological investigations and provide additional characterization of isolates. Most genotypes carrying bla(OXA-23-like) were PCR positive for a yeeA-bla(OXA-23) fragment found in an AbaR4-type island, suggesting that this is widespread.

  2. Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Yoko Miyasaki

    Full Text Available The number of fully active antibiotic options that treat nosocomial infections due to multidrug-resistant Acinetobacter baumannii (A. baumannii is extremely limited. Magnolia officinalis, Mahonia bealei, Rabdosia rubescens, Rosa rugosa, Rubus chingii, Scutellaria baicalensis, and Terminalia chebula plant extracts were previously shown to have growth inhibitory activity against a multidrug-resistant clinical strain of A. baumannii. In this study, the compounds responsible for their antimicrobial activity were identified by fractionating each plant extract using high performance liquid chromatography, and determining the antimicrobial activity of each fraction against A. baumannii. The chemical structures of the fractions inhibiting >40% of the bacterial growth were elucidated by liquid chromatography/mass spectrometry analysis and nuclear magnetic resonance spectroscopy. The six most active compounds were identified as: ellagic acid in Rosa rugosa; norwogonin in Scutellaria baicalensis; and chebulagic acid, chebulinic acid, corilagin, and terchebulin in Terminalia chebula. The most potent compound was identified as norwogonin with a minimum inhibitory concentration of 128 µg/mL, and minimum bactericidal concentration of 256 µg/mL against clinically relevant strains of A. baumannii. Combination studies of norwogonin with ten anti-Gram negative bacterial agents demonstrated that norwogonin did not enhance the antimicrobial activity of the synthetic antibiotics chosen for this study. In conclusion, of all identified antimicrobial compounds, norwogonin was the most potent against multidrug-resistant A. baumannii strains. Further studies are warranted to ascertain the prophylactic and therapeutic potential of norwogonin for infections due to multidrug-resistant A. baumannii.

  3. In vitro activities of antimicrobial agents, alone and in combination, against Acinetobacter baumannii isolated from blood.

    Science.gov (United States)

    Chang, S C; Chen, Y C; Luh, K T; Hsieh, W C

    1995-11-01

    In vitro activities of 15 antimicrobial agents against 90 strains of Acinetobacter baumannii isolated from blood cultures from hospitalized patients were determined using the agar dilution method. Imipenem, ofloxacin, and ciprofloxacin had the best antimicrobial activity with minimum inhibitory concentrations (MIC50s) of 0.25 mu g/ml and MIC90s of 0.5-1 mu g/ml. beta-lactam antibiotics other than imipenem had poor activity, with MIC50s ranging from 8 to 64 mu g/ml and MIC90s from 32 to > or = 256 mu g/ml. The checkerboard titration method was used to study the effects of combination of two antimicrobial agents. Combinations of ceftazidime, aztreonam, imipenem, or ciprofloxacin with amikacin showed either synergistic effects or partial synergistic effects for 40.9%-86.4% of 22 tested strains. The best in vitro activity was observed with the combination of imipenem and amikacin. No antagonistic effects were observed with the combination of imipenem and amikacin. Synergistic effects were confirmed by time-kill curve studies. In conclusion, imipenem, ofloxacin, and ciprofloxacin were the three most active agents against human blood isolates of A. baumannii. The combination of a beta-lactam or ciprofloxacin with amikacin was synergistic for some of the isolates.

  4. Acinetobacter baumannii biofilms: variations among strains and correlations with other cell properties.

    Science.gov (United States)

    McQueary, Christin N; Actis, Luis A

    2011-04-01

    Acinetobacter baumannii is an opportunistic pathogen that causes serious infections in humans by colonizing and persisting on surfaces normally found in hospital settings. The capacity of this pathogen to persist in these settings could be due to its ability to form biofilms on inanimate surfaces. This report shows that although the ATCC 19606(T) type strain and 8 different clinical isolates form biofilms, there are significant variations in the cell density and microscopic structures of these cell aggregates, with 3 of the isolates forming pellicles floating on the surface of stagnant broth cultures. PCR indicated that, like ATCC 19606(T), all 8 clinical isolates harbor all the genetic components of the CsuA/BABCDE chaperone-usher pili assembly system, which is needed for biofilm formation on plastic. Pili detection in cells of all strains examined supports the presence and function of a pilus assembly system. However, only one of them produced the putative ATCC 19606(T) CsuA/B pilin subunit protein. Hydrophobicity tests and motility assays also showed significant variations among all tested strains and did not result in direct correlations between the biofilm phenotype and cell properties that could affect biofilm formation on abiotic surfaces. This lack of correlation among these 3 phenotypes may reflect some of the variations already reported with this pathogen, which may pose a challenge in the treatment of the infections this pathogen causes in humans using biofilm formation on abiotic surfaces as a target.

  5. Multi-drug resistant Acinetobacter infections in critically injured Canadian forces soldiers

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    Brisebois Ronald

    2007-08-01

    Full Text Available Abstract Background Military members, injured in Afghanistan or Iraq, have returned home with multi-drug resistant Acinetobacter baumannii infections. The source of these infections is unknown. Methods Retrospective study of all Canadian soldiers who were injured in Afghanistan and who required mechanical ventilation from January 1 2006 to September 1 2006. Patients who developed A. baumannii ventilator associated pneumonia (VAP were identified. All A. baumannii isolates were retrieved for study patients and compared with A. baumannii isolates from environmental sources from the Kandahar military hospital using pulsed-field gel electrophoresis (PFGE. Results During the study period, six Canadian Forces (CF soldiers were injured in Afghanistan, required mechanical ventilation and were repatriated to Canadian hospitals. Four of these patients developed A. baumannii VAP. A. baumannii was also isolated from one environmental source in Kandahar – a ventilator air intake filter. Patient isolates were genetically indistinguishable from each other and from the isolates cultured from the ventilator filter. These isolates were resistant to numerous classes of antimicrobials including the carbapenems. Conclusion These results suggest that the source of A. baumannii infection for these four patients was an environmental source in the military field hospital in Kandahar. A causal linkage, however, was not established with the ventilator. This study suggests that infection control efforts and further research should be focused on the military field hospital environment to prevent further multi-drug resistant A. baumannii infections in injured soldiers.

  6. Quantification of chemotaxis-related alkane accumulation in Acinetobacter baylyi using Raman microspectroscopy.

    Science.gov (United States)

    Li, Hanbing; L Martin, Francis Luke; Zhang, Dayi

    2017-03-03

    Alkanes are one of the most widespread contaminants in the natural environment, primarily as a consequence of biological synthesis and oil spills. Many indigenous microbes metabolize alkanes, and the chemotaxis and accumulation in some strains has been identified. For the first time, we apply Raman microspectroscopy to identify such chemotaxis-related affinity, and quantify the alkane concentrations via spectral alterations. Raman spectral alterations were only found for the alkane chemo-attractant bacteria Acinetobacter baylyi ADP1, not for Pseudomonas fluorescence, which exhibits limited chemotaxis towards alkane. The significant alterations were attributed to the strong chemotactic ability of A. baylyi enhancing the affinity and accumulation of alkane molecules on cell membranes or cellular internalization. Spectral fingerprints of A. baylyi significantly altered after 1-h exposure to pure alkanes (dodecane or tetradecane) and alkane mixtures (mineral oil or crude oil), but not monocyclic aromatic hydrocarbons (MAHs) or polycyclic aromatic hydrocarbons (PAHs). A semi-log linear regression relationship between Raman spectral alterations and alkane concentrations showed its feasibility in quantifying alkane concentration in environmental samples. Pure alkanes or alkane mixtures exhibited different limits of detection and regression slopes, indicating that the chemotaxis-related alkane accumulation in A. baylyi is dependent on the carbon chain length. This work provides a novel biospectroscopy approach to characterize the chemotaxis-related alkane bioaccumulation, and has immense potential for fast and high-throughput screening bacterial chemotaxis.

  7. Crystal Structure of Hcp from Acinetobacter baumannii: A Component of the Type VI Secretion System.

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    Ruiz, Federico M; Santillana, Elena; Spínola-Amilibia, Mercedes; Torreira, Eva; Culebras, Esther; Romero, Antonio

    2015-01-01

    The type VI secretion system (T6SS) is a bacterial macromolecular machine widely distributed in Gram-negative bacteria, which transports effector proteins into eukaryotic host cells or other bacteria. Membrane complexes and a central tubular structure, which resembles the tail of contractile bacteriophages, compose the T6SS. One of the proteins forming this tube is the hemolysin co-regulated protein (Hcp), which acts as virulence factor, as transporter of effectors and as a chaperone. In this study, we present the structure of Hcp from Acinetobacter baumannii, together with functional and oligomerization studies. The structure of this protein exhibits a tight β barrel formed by two β sheets and flanked at one side by a short α-helix. Six Hcp molecules associate to form a donut-shaped hexamer, as observed in both the crystal structure and solution. These results emphasize the importance of this oligomerization state in this family of proteins, despite the low similarity of sequence among them. The structure presented in this study is the first one for a protein forming part of a functional T6SS from A. baumannii. These results will help us to understand the mechanism and function of this secretion system in this opportunistic nosocomial pathogen.

  8. Carbapenem-resistant Acinetobacter ventilator-associated pneumonia: Clinical characteristics and outcome

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    Mohan Gurjar

    2013-01-01

    Full Text Available Objective: To study the clinical characteristics and 28-days mortality in patients with ventilator-associated pneumonia (VAP due to carbapenem-resistant Acinetobacter (CRA. Design: Retrospective, observational, cohort study. Setting: Intensive care unit (ICU of a university hospital. Materials and Methods: Microbiologically confirmed VAP due to CRA infection. Intervention: None. Results: Out of 87 patients with VAP due to CRA, 60 (69% were male; whose median age was 51 years; 73 (84% patients were medical; 26 (30% had history of hospitalization in last 3 months; median acute physiology and chronic health evaluation (APACHE II was 15 and median SOFA 9 at admission; primary reason for ICU admission was respiratory failure (34%; 46 (53% patients had more than 2 organ failure at ICU admission; median length of ICU stay was 19 days; 66 (76% patients need vasoactive agents during ICU stay, whereas 55 (63% patients had renal failure; median duration of mechanical ventilation was 17 days; 22 (25% patients had acute respiratory distress syndrome (ARDS during ICU stay; 72 (83% patients had exposure to carbapenem before inclusion in the study; 33 (38% patients had same organism at other sites. In the follow-up, 47 (54% patient survived at 28 days after having VAP; whereas only 40 (46% patients were discharged from the hospital. Conclusions: CRA-VAP has high crude mortality. Advanced age; severity of illness and presence of pneumonia at ICU admission; and presence of shock, ARDS and renal failure have impact on outcome in these patients.

  9. Biodegradation of malathion by Acinetobacter johnsonii MA19 and optimization of cometabolism substrates

    Institute of Scientific and Technical Information of China (English)

    XIE Shan; LIU Junxin; LI Lin; QIAO Chuanling

    2009-01-01

    To enhance the removal efficiency of malathion in the wastewater from organophosphate pesticide mill, a bacterium, Acinetobacter johnsonii MA19, that could degrade malathion with cometabolism was isolated from malathion-polluted soil samples using enrichment culture techniques. Four kinds of additional compounds, sodium succinate, sodium acetate, glucose, and fructose were tested to choose a favorite carbon source for the cometabolism of strain MA19. The results showed that sodium succinate and sodium acetate could promote malathion biodegradation and cell growth. The investigation results of effects of sodium succinate concentrations on the malathion biodegradation indicated that the more sodium succinate supplied resulted in quick degradation ofmalathion and fast cells multiplied. Zero-order kinetic model was appropriate to describe the malathion biodegradation when the concentration of sodium succinate was more than 0.5144 g/L. The degradation rate constant (K) reached the maximum value of 3.5837 mg/(L·h) when the mass ratio of sodium succinate to malathion was 128.6 mg/mg. The aquatic toxicity of the malathion was evaluated using the test organism, Limnodrilus hoffmeisteri. The data obtained suggested that the toxicity of malathion could be ignored after 84 h biodegradation. Our result demonstrates the potential for using bacterium A. Johnsonii MA19 for malathion biodegradation and environmental bioremediation when some suitable conventional carbon sources are supplied.

  10. Inactivation of Acinetobacter baumannii Biofilms on Polystyrene, Stainless Steel, and Urinary Catheters by Octenidine Dihydrochloride

    Science.gov (United States)

    Narayanan, Amoolya; Nair, Meera S.; Karumathil, Deepti P.; Baskaran, Sangeetha A.; Venkitanarayanan, Kumar; Amalaradjou, Mary Anne Roshni

    2016-01-01

    Acinetobacter baumannii is a major nosocomial pathogen causing human infections with significant mortality rates. In most cases, infections are acquired through exposure to A. baumannii biofilms that persist on contaminated hospital equipment and surfaces. Thus, it is imperative to develop effective measures for controlling A. baumannii biofilms in nosocomial settings. This study investigated the efficacy of octenidine dihydrochloride (OH), a new generation disinfectant for reducing A. baumannii biofilms on polystyrene, stainless steel and catheters. OH at 0.3% (5 mM), 0.6% (10 mM), and 0.9% (15 mM) was effective in significantly inactivating A. baumannii biofilms on all tested surfaces (P < 0.05). Furthermore, OH was equally effective in inactivating biofilms of multidrug resistant and drug susceptible A. baumannii isolates. In addition, confocal imaging revealed the predominance of dead cells in the OH-treated samples in comparison to the control. Further, scanning electron microscopy of biofilms formed on catheters revealed that OH treatment significantly reduced A. baumannii biofilm populations in corroboration with our antibiofilm assay. These data underscore the efficacy of OH in inactivating A. baumannii biofilms, thereby suggesting its potential use as a disinfectant or a catheter lock solution to control A. baumannii infections. PMID:27375572

  11. Inactivation of Acinetobacter baumannii Biofilms on Polystyrene, Stainless Steel, and Urinary Catheters by Octenidine Dihydrochloride.

    Science.gov (United States)

    Narayanan, Amoolya; Nair, Meera S; Karumathil, Deepti P; Baskaran, Sangeetha A; Venkitanarayanan, Kumar; Amalaradjou, Mary Anne Roshni

    2016-01-01

    Acinetobacter baumannii is a major nosocomial pathogen causing human infections with significant mortality rates. In most cases, infections are acquired through exposure to A. baumannii biofilms that persist on contaminated hospital equipment and surfaces. Thus, it is imperative to develop effective measures for controlling A. baumannii biofilms in nosocomial settings. This study investigated the efficacy of octenidine dihydrochloride (OH), a new generation disinfectant for reducing A. baumannii biofilms on polystyrene, stainless steel and catheters. OH at 0.3% (5 mM), 0.6% (10 mM), and 0.9% (15 mM) was effective in significantly inactivating A. baumannii biofilms on all tested surfaces (P < 0.05). Furthermore, OH was equally effective in inactivating biofilms of multidrug resistant and drug susceptible A. baumannii isolates. In addition, confocal imaging revealed the predominance of dead cells in the OH-treated samples in comparison to the control. Further, scanning electron microscopy of biofilms formed on catheters revealed that OH treatment significantly reduced A. baumannii biofilm populations in corroboration with our antibiofilm assay. These data underscore the efficacy of OH in inactivating A. baumannii biofilms, thereby suggesting its potential use as a disinfectant or a catheter lock solution to control A. baumannii infections.

  12. Characterization and Detection of Endolysin Gene from Three Acinetobacter baumannii Bacteriophages Isolated from Sewage Water.

    Science.gov (United States)

    Kitti, Thawatchai; Thummeepak, Rapee; Thanwisai, Aunchalee; Boonyodying, Kamala; Kunthalert, Duangkamol; Ritvirool, Pannika; Sitthisak, Sutthirat

    2014-12-01

    Acinetobacter baumannii is an opportunistic pathogen that exists in hospital environments. The emergence of multidrug resistant A. baumannii (MDRAB) has been reported worldwide. It is necessary to find a novel and effective treatment for MDRAB infection. In this study, three bacteriophages, designated as ØABP-01, ØABP-02 and ØABP-04 were selected for analysis. Transmission electron microscopy showed that bacteriophage ØABP-01 belonged to the Podoviridae family and bacteriophage ØABP-02 and ØABP-04 are classified into the family Myoviridae. ØABP-01 had the widest host range. ØABP-01, ØABP-02 and ØABP-04 exhibited a latent period of 15, 20 and 20 min. The burst sizes of the three bacteriophages were 110, 120 and 150 PFU/cell. DNA restriction analysis using EcoRI, HindIII, PstI, SphI, BamHI and SmaI showed different DNA fragment patterns between the three bacteriophages. ØABP-01 and ØABP-04 was positive for the endolysin gene as determined by PCR. In conclusion, bacteriophage ØABP-01 showed broad host-specificity, good lytic activity and a short latency period, making it an appropriate candidate for studying the control and diagnosis associated with MDRAB infections.

  13. Biotechnological tools to improve bioremediation of phenol by Acinetobacter sp. RTE1.4.

    Science.gov (United States)

    Paisio, Cintia E; Talano, Melina A; González, Paola S; Magallanes-Noguera, Cynthia; Kurina-Sanz, Marcela; Agostini, Elizabeth

    2016-09-01

    The use of native bacteria is a useful strategy to decontaminate industrial effluents as well as the environment. Acinetobacter sp. RTE1.4 was previously isolated from polluted environments and constitutes a promising alternative for this purpose due to its capability to remove phenol from synthetic solutions and industrial effluents. In this work, this strain was identified at species level as A. tandoii RTE1.4. Phenol degradation pathway was studied and some reaction intermediates were detected, confirming that this strain degraded phenol through ortho-cleavage of the aromatic ring. Phenol removal assays were carried out in a stirred tank bioreactor and a complete degradation of the contaminant was achieved after only 7 h, at an aeration rate of 3 vvm and at agitation of 600 rpm. Moreover, this bacterium was immobilized into calcium alginate beads and an increase in phenol biodegradation with respect to free cells was observed. The immobilized cells were reused for four consecutive cycles and stored at 4°C for 9 months, during which phenol removal efficiency was maintained. Post-removal solutions were evaluated by Microtox® test, showing a toxicity reduction after bacterial treatment. These findings demonstrated that A. tandoii RTE1.4 might be considered as a useful biotechnological tool for an efficient treatment of different solutions contaminated with phenol in bioreactors, using either free or immobilized cells.

  14. Thai ethnomedicinal plants as resistant modifying agents for combating Acinetobacter baumannii infections

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    Phatthalung Pinanong

    2012-04-01

    Full Text Available Abstracts Background Acinetobacter baumannii is well-recognized as an important nosocomial pathogen, however, due to their intrinsic resistance to several antibiotics, treatment options are limited. Synergistic effects between antibiotics and medicinal plants, particularly their active components, have intensively been studied as alternative approaches. Methods Fifty-one ethanol extracts obtained from 44 different selected medicinal plant species were tested for resistance modifying agents (RMAs of novobiocin against A. baumannii using growth inhibition assay. Results At 250 μg/ml, Holarrhena antidysenterica, Punica granatum, Quisqualis indica, Terminalia bellirica, Terminalia chebula, and Terminalia sp. that possessed low intrinsic antibacterial activity significantly enhanced the activity of novobiocin at 1 μg/ml (1/8xminimum inhibitory concentration against this pathogen. Holarrhena antidysenterica at 7.8 μg/ml demonstrated remarkable resistant modifying ability against A. baumannii in combination with novobiocin. The phytochemical study revealed that constituents of this medicinal plant contain alkaloids, condensed tannins, and triterpenoids. Conclusion The use of Holarrhena antidysenterica in combination with novobiocin provides an effective alternative treatment for multidrug resistant A. baumannii infections.

  15. Differential Role of the T6SS in Acinetobacter baumannii Virulence.

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    Guillermo D Repizo

    Full Text Available Gram-negative bacteria, such as Acinetobacter baumannii, are an increasing burden in hospitals worldwide with an alarming spread of multi-drug resistant (MDR strains. Herein, we compared a type strain (ATCC17978, a non-clinical isolate (DSM30011 and MDR strains of A. baumannii implicated in hospital outbreaks (Ab242, Ab244 and Ab825, revealing distinct patterns of type VI secretion system (T6SS functionality. The T6SS genomic locus is present and was actively transcribed in all of the above strains. However, only the A. baumannii DSM30011 strain was capable of killing Escherichia coli in a T6SS-dependent manner, unlike the clinical isolates, which failed to display an active T6SS in vitro. In addition, DSM30011 was able to outcompete ATCC17978 as well as Pseudomonas aeruginosa and Klebsiella pneumoniae, bacterial pathogens relevant in mixed nosocomial infections. Finally, we found that the T6SS of DSM30011 is required for host colonization of the model organism Galleria mellonella suggesting that this system could play an important role in A. baumannii virulence in a strain-specific manner.

  16. Production and characterization of L-fucose dehydrogenase from newly isolated Acinetobacter sp. strain SA-134.

    Science.gov (United States)

    Ohshiro, Takashi; Morita, Noriyuki

    2014-01-01

    Microorganisms producing L-fucose dehydrogenase were screened from soil samples, and one of the isolated bacterial strains SA-134 was identified as Acinetobacter sp. by 16S rDNA gene analysis. The strain grew well utilizing L-fucose as a sole source of carbon, but all other monosaccharides tested such as D-glucose and D-arabinose did not support the growth of the strain in the absence of L-fucose. D-Arabinose inhibited the growth even in the culture medium containing L-fucose. Although the strain grew on some organic acids and amino acids such as citric acid and L-alanine as sole sources of carbon, the enzyme was produced only in the presence of L-fucose. The fucose dehydrogenase was purified to apparently homogeneity from the strain, and the native enzyme was a monomer of 25 kD. L-Fucose and D-arabinose were good substrates for the enzyme, but L-galactose was a poor substrate. The enzyme acted on both NAD(+) and NADP(+) in the similar manner.

  17. The antibacterial activity of some essential oils against clinical isolates of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Mohaddese Mahboubi

    2014-10-01

    Full Text Available Acinetobacter baumannii is categorized as a red alert pathogen that is increasingly associated with a high mortality rate in infected patients due to its resistance to extensive antibiotics. In this study, we evaluated the antibacterial activities of some essential oils (Oliveria decumbens, Pelargonium graveolens, Eugenia caryophyllata, Ziziphora tenuir and Trachyspermum copticum oils against 32 clinical isolates of A. baumannii. The antibacterial evaluations and chemical composition of essential oils was determined. Thymol, eugenol, -terpineol, -citronellol and thymol were the chief portions of T. copticum, E. caryophyllata, Z. tenuir, O. decumbens and P. graveolens oils, respectively. The MIC values of oils against these clinical isolates revealed the three subsets of oils including 1- T. copticum, E. caryophyllata and O. decumbens, 2- Z. tenuir and 3- P. graveolens oils. These oils showed the synergistic activity with amikacin, the lower Fractional Inhibitory Concentration Index (FICI was for P. graveolens oil (0.23 and the higher FICI was for E. caryophyllata (0.325.

  18. Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, Zainul Akmar; Zakaria, Zainoha [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Surif, Salmijah [Department of Environmental Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Ahmad, Wan Azlina [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)], E-mail: azlina@kimia.fs.utm.my

    2007-09-05

    Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L{sup -1} of Cr(VI) was reduced at a flow rate of 8.0 mL min{sup -1}. The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment.

  19. Purification and Characterization of Catalase from Marine Bacterium Acinetobacter sp. YS0810

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    Xinhua Fu

    2014-01-01

    Full Text Available The catalase from marine bacterium Acinetobacter sp. YS0810 (YS0810CAT was purified and characterized. Consecutive steps were used to achieve the purified enzyme as follows: ethanol precipitation, DEAE Sepharose ion exchange, Superdex 200 gel filtration, and Resource Q ion exchange. The active enzyme consisted of four identical subunits of 57.256 kDa. It showed a Soret peak at 405 nm, indicating the presence of iron protoporphyrin IX. The catalase was not apparently reduced by sodium dithionite but was inhibited by 3-amino-1,2,4-triazole, hydroxylamine hydrochloride, and sodium azide. Peroxidase-like activity was not found with the substrate o-phenylenediamine. So the catalase was determined to be a monofunctional catalase. N-terminal amino acid of the catalase analysis gave the sequence SQDPKKCPVTHLTTE, which showed high degree of homology with those of known catalases from bacteria. The analysis of amino acid sequence of the purified catalase by matrix-assisted laser desorption ionization time-of-flight mass spectrometry showed that it was a new catalase, in spite of its high homology with those of known catalases from other bacteria. The catalase showed high alkali stability and thermostability.

  20. Hexavalent chromium reduction by Acinetobacter haemolyticus isolated from heavy-metal contaminated wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Zakaria, Zainul Akmar [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Zakaria, Zainoha [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Surif, Salmijah [Department of Environmental Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Ahmad, Wan Azlina [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)]. E-mail: azlina@kimia.fs.utm.my

    2007-07-19

    Possible application of a locally isolated environmental isolate, Acinetobacter haemolyticus to remediate Cr(VI) contamination in water system was demonstrated. Cr(VI) reduction by A. haemolyticus seems to favour the lower concentrations (10-30 mg/L). However, incomplete Cr(VI) reduction occurred at 70-100 mg/L Cr(VI). Initial specific reduction rate increased with Cr(VI) concentrations. Cr(VI) reduction was not affected by 1 or 10 mM sodium azide (metabolic inhibitor), 10 mM of PO{sub 4} {sup 3-}, SO{sub 4} {sup 2-}, SO{sub 3} {sup 2-}, NO{sub 3} {sup -} or 30 mg/L of Pb(II), Zn(II), Cd(II) ions. However, heat treatment caused significant dropped in Cr(VI) reduction to less than 20% only. A. haemolyticus cells loses its shape and size after exposure to 10 and 50 mg Cr(VI)/L as revealed from TEM examination. The presence of electron-dense particles in the cytoplasmic region of the bacteria suggested deposition of chromium in the cells.

  1. Cloning, expression, and characterization of a novel diketoreductase from Acinetobacter baylyi

    Institute of Scientific and Technical Information of China (English)

    Xuri Wu; Nan Liu; Yunmian He; Yijun Chen

    2009-01-01

    Reductions of carbonyl groups catalyzed by oxidoreduc-tases are involved in all biological processes and are often a class of important biocatalyst. In this article, we report a novel enzyme designated as diketoreductase (DKR) that was able to reduce two carbonyl groups in a diketo ester to corresponding dihydroxy ester with excel-lent stereoselectivity. The DKR was cloned from Acinetobacter baylyi by reverse genetic method, heteroge-neously expressed in Escherichia coli, and purified to homogeneity by two chromatographic steps. This novel enzyme exhibited dual cofactor specificity, with a prefer-ence of NADH over NADPH. The dihydroxy ester product catalyzed by the DKR was only 3R,5S-stereoi-somer with both diastereomeric excess and enantiomeric excess values more than 99.5%. In addition, some bio-chemical properties of the enzyme, such as the optimal pH and temperature, were also characterized. Furthermore, sequence analysis indicated that this new enzyme was homologous to bacterial 3-hydroxyacyl coenzyme-A dehydrogenase. More importantly, based on the unique catalytic activity and excellent stereoselec-tivity, the DKR could be utilized in the synthesis of valuable chiral drug intermediates, such as Lipitor .

  2. Emergence of Acinetobacter baumannii ST730 carrying the bla OXA-72 gene in Brazil

    Science.gov (United States)

    Pagano, Mariana; Rozales, Franciéli P; Bertolini, Diego; Rocha, Lisiane; Sampaio, Jorge LM; Barth, Afonso L; Martins, Andreza F

    2016-01-01

    Over the last decade, Acinetobacter baumannii resistant to carbapenems has emerged in many medical centres and has been commonly associated with high morbimortality. In Brazil, this resistance is mainly attributed to the spread of OXA-23-producing clones and, to a lesser extent, to OXA-143-producing clones. Here, we describe, for the first time, two OXA-72-producing A. baumannii isolates in southern Brazil to a broad spectrum of antibiotics, except polymyxin B and tigecycline. Molecular typing by multilocus sequence typing (MLST) demonstrated that both OXA-72-producing isolates belong to a new sequence type (ST), ST730, which was recently identified in OXA-23-producing A. baumannii isolates in São Paulo, Brazil. We demonstrate that the two A. baumannii ST730 isolates carrying blaOXA-72share a common ancestral origin with the blaOXA-23producers in Brazil. This observation reinforces the importance of strain-typing methods in order to clarify the dynamics of the emergence of new clones in a geographic region. PMID:27653364

  3. Modeling the impact of interventions against Acinetobacter baumannii transmission in intensive care units.

    Science.gov (United States)

    Doan, Tan N; Kong, David C M; Marshall, Caroline; Kirkpatrick, Carl M J; McBryde, Emma S

    2016-01-01

    The efficacy of infection control interventions against Acinetobacter baumannii remains unclear, despite such information being critical for effective prevention of the transmission of this pathogen. Mathematical modeling offers an alternative to clinical trials, which may be prohibitively expensive, unfeasible or unethical, in predicting the impact of interventions. Furthermore, it allows the ability to ask key "what if" questions to evaluate which interventions have the most impact. We constructed a transmission dynamic model to quantify the effects of interventions on reducing A. baumannii prevalence and the basic reproduction ratio (R0) in intensive care units (ICUs). We distinguished between colonization and infection, and incorporated antibiotic exposure and transmission from free-living bacteria in the environment. Under the assumptions and parameterization in our model, 25% and 18% of patients are colonized and infected with A. baumannii, respectively; and R0 is 1.4. Improved compliance with hand hygiene (≥87%), enhanced environmental cleaning, reduced length of ICU stay of colonized patients (≤ 10 days), shorter durations of antibiotic treatment of A. baumannii (≤6 days), and isolation of infected patients combined with cleaning of isolation rooms are effective, reducing R0 to below unity. In contrast, expediting the recovery of the intestinal microbiota (e.g. use of probiotics) is not effective. This study represents a biologically realistic model of the transmission dynamics of A. baumannii, and the most comprehensive analysis of the effectiveness of interventions against this pathogen. Our study provides important data for designing effective infection control interventions.

  4. Antimicrobial Resistance of Acinetobacter baumannii to Imipenem in Iran: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Pourhajibagher, Maryam; Hashemi, Farhad B; Pourakbari, Babak; Aziemzadeh, Masoud; Bahador, Abbas

    2016-01-01

    Imipenem-resistant multi-drug resistant (IR-MDR) Acinetobacter baumannii has been emerged as a morbidity successful nosocomial pathogen throughout the world.To address imipenem being yet the most effective antimicrobial agent against A. baumannii to control outbreaks and treat patients, a systematic review and meta-analysis was performed to evaluate the prevalence of IR-MDR A. baumannii. We systematically searched Web of Science, PubMed, MEDLINE, Science Direct, EMBASE, Scopus, Cochrane Library, Google Scholar, and Iranian databases to identify studies addressing the antibiotic resistance of A. baumannii to imipenem and the frequency of MDR strains in Iran. Out of 58 articles and after a secondary screening using inclusion and exclusion criteria and on the basis of title and abstract evaluation, 51 studies were selected for analysis. The meta-analysis revealed that 55% [95% confidence interval (CI), 53.0-56.5] of A. baumannii were resistant to imipenem and 74% (95% CI, 61.3-83.9) were MDR. The MDR A. baumannii population in Iran is rapidly changing toward a growing resistance to imipenem. Our findings highlight the critical need for a comprehensive monitoring and infection control policy as well as a national susceptibility review program that evaluates IR-MDR A. baumannii isolates from various parts of Iran.

  5. In vitro sensitivity of Acinetobacter baumannii and Pseudomonas aeruginosa to carbapenems among intensive care unit patients.

    Science.gov (United States)

    Guzek, A; Korzeniewski, K; Nitsch-Osuch, Aneta; Rybicki, Z; Prokop, E

    2013-01-01

    Acinetobacter baumannii and Pseudomonas aeruginosa pathogens are the most common causes of fatal pneumonia among patients treated in Intensive Care Units (ICU). Carbapenems remain a group of antibiotics characterized by the highest effectiveness in treatment of heavy infections of the lower respiratory tract. This study compared in vitro sensitivity of A. baumannii and P. aeruginosa to three carbapenems: imipenem, meropenem and doripenem. The material was collected from 71 patients treated in the ICU from April 2009 to January 2010. Bronchial tree was the predominant source of samples. Fifty-four strains of A. baumannii and 17 strains of P. aeruginosa were analyzed. Sensitivity to carbapenems was interpreted in line with Clinical and Laboratory Standard Institute (CLSI) and European Committee for Antimicrobial Susceptibility Testing (EUCAST) criteria (imipenem and meropenem) or in compliance with the Food and Drug Administration (FDA) and CLSI guidelines (doripenem). We found that A. baumannii was significantly more often sensitive to imipenem than to doripenem and meropenem, but only according to the CLSI and FDA and not EUCAST criteria. The sensitivity of P. aeruginosa was higher to imipenem than to doripenem and meropenem, according to both CLSI and EUCAST criteria (64.7 %). We conclude that the EUCAST criteria demonstrate a higher rigor than those of CLSI and FDA in the determination of carbapenems sensitivity. Imipenem appears more effective than doripenem and meropenem in treatment of A. baumannii and P. aeruginosa infections.

  6. Colistin Resistance in Acinetobacter baumannii MDR-ZJ06 Revealed by a Multiomics Approach

    Science.gov (United States)

    Hua, Xiaoting; Liu, Lilin; Fang, Youhong; Shi, Qiucheng; Li, Xi; Chen, Qiong; Shi, Keren; Jiang, Yan; Zhou, Hua; Yu, Yunsong

    2017-01-01

    Acinetobacter baumannii has emerged as an important opportunistic pathogen due to its ability to acquire resistance to most currently available antibiotics. Colistin is often considered as the last line of therapy for infections caused by multidrug-resistant A. baumannii (MDRAB). However, colistin-resistant A. baumannii strain has recently been reported. To explore how multiple drug-resistant A. baumannii responded to colistin resistance, we compared the genomic, transcriptional and proteomic profile of A. baumannii MDR-ZJ06 to the induced colistin-resistant strain ZJ06-200P5-1. Genomic analysis showed that lpxC was inactivated by ISAba1 insertion, leading to LPS loss. Transcriptional analysis demonstrated that the colistin-resistant strain regulated its metabolism. Proteomic analysis suggested increased expression of the RND efflux pump system and down-regulation of FabZ and β-lactamase. These alterations were believed to be response to LPS loss. In summary, the lpxC mutation not only established colistin resistance but also altered global gene expression. PMID:28275586

  7. Higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals in Beijing.

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    Chuanfu Zhang

    Full Text Available Multidrug resistant microbes present in the environment are a potential public health risk. In this study, we investigate the presence of New Delhi metallo-β-lactamase 1 (NDM-1 producing bacteria in the 99 water samples in Beijing City, including river water, treated drinking water, raw water samples from the pools and sewage from 4 comprehensive hospitals. For the bla NDM-1 positive isolate, antimicrobial susceptibility testing was further analyzed, and Pulsed Field Gel Electrophoresis (PFGE was performed to determine the genetic relationship among the NDM-1 producing isolates from sewage and human, as well as the clinical strains without NDM-1. The results indicate that there was a higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals, while no NDM-1 producing isolates were recovered from samples obtained from the river, drinking, or fishpond water. Surprisingly, these isolates were markedly different from the clinical isolates in drug resistance and pulsed field gel electrophoresis profiles, suggesting different evolutionary relationships. Our results showed that the hospital sewage may be one of the diffusion reservoirs of NDM-1 producing bacteria.

  8. OmpW is a potential target for eliciting protective immunity against Acinetobacter baumannii infections.

    Science.gov (United States)

    Huang, Weiwei; Wang, Shijie; Yao, Yufeng; Xia, Ye; Yang, Xu; Long, Qiong; Sun, Wenjia; Liu, Cunbao; Li, Yang; Ma, Yanbing

    2015-08-26

    Acinetobacter baumannii (A. baumannii) is an important conditioned pathogen that causes nosocomial and community-associated infections. In this study, we sought to investigate whether outer membrane protein W (OmpW) is a potential target for eliciting protective immunity against A. baumannii infections. Mice immunized with the fusion protein thioredoxin-OmpW generated strong OmpW-specific IgG responses. In a sepsis model, both active and passive immunizations against OmpW effectively protected mice from A. baumannii infections. This protection was demonstrated by a significantly improved survival rate, reduced bacterial burdens within organs, and the suppressed accumulation of inflammatory cytokines and chemokines in sera. Opsonophagocytic assays with murine macrophage RAW264.7 cells indicated that the bactericidal effects of the antisera derived from the immunized mice are mediated synergistically by specific antibodies and complement components. The antisera presented significant opsonophagocytic activities against homologous strains and clonally distinct clinical isolates in vitro. Protein data analysis showed that the sequence of OmpW, which has a molecule length of 183 amino acids, is more than 91% conserved in reported A. baumannii strains. In conclusion, we identified OmpW as a highly immunogenic and conserved protein as a valuable antigen candidate for the development of an effective vaccine or the preparation of antisera to control A. baumannii infections.

  9. The First Outbreak Caused by Acinetobacter baumannii ST208 and ST195 in China

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    Junyan Qu

    2016-01-01

    Full Text Available This study aimed to analyze the clinical characteristics of patients and molecular mechanisms of the first outbreak mainly caused by sequence types (STs 208 multidrug resistant (MDR Acinetobacter baumannii in China. A total of 10 clinical samples were collected from 5 patients who were involved in the outbreak. Bacterial identification and antibiotic sensitivity tests were performed by the VITEK-2 COMPACT automated system. MICs of tigecycline for clinical isolates were determined using broth microdilution. The clonal relatedness of A. baumannii clinical isolates in our local settings was determinated by pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST. A total of 7 A. baumannii strains were isolated and all were MDR strains; two of them were carbapenem-nonsusceptible strains. blaOXA-23 was the only acquired carbapenemase gene in the isolates. The isolates belonged to a single clonal pulsotype determined by PFGE and two sequences types (STs determined by MLST. The isolates belonged to the globally disseminated clonal complex 92, among which ST195 and ST208 were the most common sequence types (71.43% and 28.57%. The outbreak was successfully controlled by stringent infection control measures, especially improving the hand hygiene compliance and enhancing antimicrobial stewardship. In conclusion, this is the first description of an outbreak caused mainly by A. baumannii of ST208 in China. Infection control measures should be strengthened when infection outbreaks in hospital.

  10. Comparative transcriptomics analyses of the different growth states of multidrug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Li, Shuai; Li, Haitao; Qi, Tianjie; Yan, Xixin; Wang, Boli; Guan, Jitao; Li, Yu

    2017-01-01

    Multidrug-resistant (MDR) Acinetobacter baumannii is an important bacterial pathogen commonly associated with hospital acquired infections. A. baumannii can remain viable and hence virulent in the environment for a long period of time due primarily to its ability to form biofilms. A total of 459 cases of MDR A. baumannii our hospital collected from March 2014 to March 2015 were examined in this study, and a representative isolate selected for high-throughput mRNA sequencing and comparison of gene expression profiles under the biofilm and exponential growth conditions. Our study found that the same bacteria indeed exhibited differential mRNA expression under different conditions. Compared to the rapidly growing bacteria, biofilm bacteria had 106 genes upregulated and 92 genes downregulated. Bioinformatics analyses suggested that many of these genes are involved in the formation and maintenance of biofilms, whose expression also depends on the environment and specific signaling pathways and transcription factors that are absent in the log phase bacteria. These differentially expressed mRNAs might contribute to A. baumannii's unique pathogenicity and ability to inflict chronic and recurrent infections.

  11. Antibacterial activity of Hibiscus sabdariffa L. calyces against hospital isolates of multidrug resistant Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    Emad Mohamed Abdallah

    2016-01-01

    Objective: To evaluate the antibacterial activity of methanol extract of Hibiscus sab-dariffa (H. sabdariffa) calyces employed in Sudanese folk medicine against five hospital isolates of multidrug resistant Acinetobacter baumannii (MDR A. baumannii). Methods: The antibacterial activity of 80% methanol extract (v/v) of H. sabdariffa calyces was evaluated by agar disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration methods. Antibiotic susceptibility of selected A. baumannii strains was tested. Results: In the present investigation, the methanol extract from the calyces of H. sabdariffa exhibited significant antibacterial properties against the non-MDR A. baumannii as well as the MDR A. baumannii strains with a zone of inhibition ranging from (11.3 ± 0.3) to (13.6 ± 0.3) mm. The relative percentage inhibition of H. sabdariffa extract (10 mg/disc) with respect to gentamicin (10 mg/disc) had potent antibacterial properties and was much more effective than gentamicin. Values of mini-mum inhibitory concentration and minimum bactericidal concentration ranged from 25 to 50 and 50 to 100 mg/mL, respectively, revealing the potential bactericidal properties of the extract. Conclusions: According to the present study, the calyces of H. sabdariffa can be used as a substitute source of the current ineffective synthetic antibiotics used against MDR A. baumannii.

  12. Monoclonal antibodies against the iron regulated outer membrane Proteins of Acinetobacter baumannii are bactericidal

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    Goel Vikas

    2001-08-01

    Full Text Available Abstract Background Iron is an important nutrient required by all forms of life.In the case of human hosts,the free iron availability is 10-18M,which is far less than what is needed for the survival of the invading bacterial pathogen.To survive in such conditions, bacteria express new proteins in their outer membrane and also secrete iron chelators called siderophores. Results/ Discussion Acinetobacter baumannii ATCC 19606, a nosocomial pathogen which grows under iron restricted conditions, expresses four new outer membrane proteins,with molecular weight ranging from 77 kDa to 88 kDa, that are called Iron Regulated Outer Membrane Proteins (IROMPs. We studied the functional and immunological properties of IROMPs expressed by A.baumanii ATCC 19606.The bands corresponding to IROMPs were eluted from SDS-PAGE and were used to immunize BALB/c mice for the production of monoclonal antibodies. Hybridomas secreting specific antibodies against these IROMPs were selected after screening by ELISA and their reactivity was confirmed by Western Blot. The antibodies then generated belonged to IgM isotype and showed bactericidical and opsonising activities against A.baumanii in vitro.These antibodies also blocked siderophore mediated iron uptake via IROMPs in bacteria. Conclusion This proves that iron uptake via IROMPs,which is mediated through siderophores,may have an important role in the survival of A.baumanii inside the host,and helps establishing the infection.

  13. Molecular Epidemiology and Characterization of Genotypes of Acinetobacter baumannii Isolates from Regions of South China.

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    Ying, Jun; Lu, Junwan; Zong, Li; Li, Ailing; Pan, Ruowang; Cheng, Cong; Li, Kunpeng; Chen, Liqiang; Ying, Jianchao; Tou, Huifen; Zhu, Chuanxin; Xu, Teng; Yi, Huiguang; Li, Jinsong; Ni, Liyan; Xu, Zuyuan; Bao, Qiyu; Li, Peizhen

    2016-05-20

    The aim of this study was to analyze the molecular epidemiologic characteristics of Acinetobacter baumannii. A total of 398 isolates were collected in 7 regions of South China from January to June of 2012. Drug sensitivity was tested toward 15 commonly used antibiotics; thus, 146 multi-drug-resistant strains (resistant to more than 7 drugs) were identified, representing 36.7% of all isolates. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used for molecular subtyping. According to the PFGE results (with a cutoff of 70% similarity for the DNA electrophoretic bands), 146 strains were subdivided into 15 clusters, with cluster A being the largest (33.6%, distributed in all districts except Jiaxing). Cluster B was also widespread and included 14.4% of all strains. In addition, MLST results revealed 11 sequence types (ST), with ST208 being the most prevalent, followed by ST191 and ST729. Furthermore, 4 novel alleles and 6 novel STs were identified. Our results showed that multi-drug-resistant A. baumannii in South China shares the origin with other widespread strains in other countries. The nosocomial infections caused by A. baumannii have been severe in South China. Continuous monitoring and judicious antibiotic use are required.

  14. Antibacterial activity of Hibiscus sabdariffa L. calyces against hospital isolates of multidrug resistant Acinetobacter baumannii

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    Emad Mohamed Abdallah

    2016-11-01

    Full Text Available Objective: To evaluate the antibacterial activity of methanol extract of Hibiscus sabdariffa (H. sabdariffa calyces employed in Sudanese folk medicine against five hospital isolates of multidrug resistant Acinetobacter baumannii (MDR A. baumannii. Methods: The antibacterial activity of 80% methanol extract (v/v of H. sabdariffa calyces was evaluated by agar disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration methods. Antibiotic susceptibility of selected A. baumannii strains was tested. Results: In the present investigation, the methanol extract from the calyces of H. sabdariffa exhibited significant antibacterial properties against the non-MDR A. baumannii as well as the MDR A. baumannii strains with a zone of inhibition ranging from (11.3 ± 0.3 to (13.6 ± 0.3 mm. The relative percentage inhibition of H. sabdariffa extract (10 mg/disc with respect to gentamicin (10 mg/disc had potent antibacterial properties and was much more effective than gentamicin. Values of minimum inhibitory concentration and minimum bactericidal concentration ranged from 25 to 50 and 50 to 100 mg/mL, respectively, revealing the potential bactericidal properties of the extract. Conclusions: According to the present study, the calyces of H. sabdariffa can be used as a substitute source of the current ineffective synthetic antibiotics used against MDR A. baumannii.

  15. In Vitro Activity of Tigecycline Against Acinetobacter baumannii: Global Epidemiology and Resistance Mechanisms.

    Science.gov (United States)

    Pournaras, Spyros; Koumaki, Vasiliki; Gennimata, Vasiliki; Kouskouni, Evangelia; Tsakris, Athanassios

    2016-01-01

    Acinetobacter baumannii is a pathogen of increasing concern, commonly causing outbreaks in the hospital environment. Of particular concern, A. baumannii strains exhibiting resistance to carbapenems, which were previously considered the treatment of choice for infected patients, have dramatically increased worldwide, leaving a few antibacterial choices. Tigecycline, a broad-spectrum modified minocycline derivative, isconsidered as a last resort drug against multidrug-resistant A. baumannii. Though, resistance to tigecycline has emerged and is growing notably following increasing tigecycline usage. Comparative evaluation of the tigecycline resistance rates reported worldwide is challenging due to the absence of official interpretative criteria for in vitro susceptibility testing and the discrepancies among the different susceptibility methodologies used, with broth microdilution being considered the reference method. Tigecycline resistance is mainly associated with resistance-nodulation-cell division (RND)-type transporters, mainly the AdeABC, AdeFGH and AdeIJK efflux pumps, but other resistance mechanisms have also been implicated. Tigecycline is still an attractive choice for A. baumannii, but further investigations are warranted so that treatment of MDR Α. baumannii could be guided by validated in vitro data.

  16. Characterisation of successive Acinetobacter baumannii isolates from a deceased haemophagocytic lymphohistiocytosis patient.

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    Choi, Hyeon Jin; Kil, Min Cheol; Choi, Ji-Young; Kim, Sun Ju; Park, Ki-Sup; Kim, Yae-Jean; Ko, Kwan Soo

    2017-01-01

    In this study, 38 Acinetobacter baumannii isolates successively isolated from blood, skin swabs and tracheal aspirates from a single patient who died from haemophagocytic lymphohistiocytosis were investigated. The isolates were collected between March 2012 and August 2012. A. baumannii genotypes were determined by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In vitro antimicrobial susceptibility testing was performed and colistin heteroresistance and persistence were evaluated. The structure of AbaR resistance islands was explored, and serum sensitivity was determined. Based on MLST analysis, all 38 A. baumannii isolates showed the same sequence type (ST138). However, PFGE analysis showed that isolates from blood samples belonged to different genotypes depending on the isolation time: whilst blood isolates obtained at the early stages showed restriction patterns similar to those of isolates from other sources, isolates obtained at later stages exhibited a distinct pattern. All isolates were resistant to imipenem, cefepime, ciprofloxacin and piperacillin/tazobactam. Five isolates from tracheal aspirates and one from a skin swab were resistant to polymyxins, and two isolates from skin swabs and one from another source were non-susceptible to tigecycline. All colistin-susceptible isolates showed heteroresistance to colistin, and four were persisters. Isolates from blood showed higher survival rates against human serum than those from other sources. This study shows that the patient was infected with more than one A. baumannii strain. Heteroresistance, persistence or evasion of the innate immune response may explain the failure of antimicrobial treatments in this patient.

  17. Aptamer-nanobody based ELASA for specific detection of Acinetobacter baumannii isolates.

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    Rasoulinejad, Samaneh; Gargari, Seyed Latif Mousavi

    2016-08-10

    Acinetobacter baumannii has turned into an important threat in nosocomial outbreak infections and multidrug resistance leading to high mortality rates in the 21st century. In recent years its mortality has increased by 15% which in part could be due to lack of a rapid and sensitive diagnostic test. In this work we introduced a new detection test for A. baumannii with two highly specific aptamer and nanobody molecules. High binding affinity DNA oligonucleotide aptamers toward A. baumannii were selected through 12 rounds of whole cell System Evolution of Ligands by EXponential enrichment process (SELEX). The SELEX procedures was monitored by flow cytometry. The dissociation constant and binding efficiency of the selected aptamer Aci49 was 7.547±1:353pM and 47.50%, respectively. A sandwich enzyme linked aptamer sorbent assay (ELASA) was designed with the biotinylated Aci49 aptamer and our previously developed nanobody against biofilm associated protein (Bap). The assay system was optimized with A. baumannii (ATCC 19606) and 47 clinical isolates of A. baumannii were tested. The threshold of detection in sandwich ELASA process was10(3) CFU/ml. The sensitivity of test toward the clinical isolates was 95.47%. Our results reveal that the sandwich ELASA is sensitive and specific enough for the rapid detection of A. baumannii from clinical isolates.

  18. Contribution of EmrAB efflux pumps to colistin resistance in Acinetobacter baumannii.

    Science.gov (United States)

    Lin, Ming-Feng; Lin, Yun-You; Lan, Chung-Yu

    2017-02-01

    Efflux pumps play an important role in antimicrobial resistance for Acinetobacter baumannii. However, the function of the Emr pump system and the relationship between Emr and drug resistance has not been characterized in A. baumannii. In this study, four possible groups of emr-like genes were found by searching a genome database. Among them, A1S_1772 (emrB) and A1S_1773 (emrA) were demonstrated to be co-transcribed as a single operon. Moreover, during osmotic stress, A1S_1772 showed the largest change in gene expression compared to the other emrB-like genes, and deletion of A1S_1772 (AB ΔemrB) significantly slowed cell growth in 20% sucrose. Using a phenotypic microarray analysis, the AB ΔemrB mutant was more susceptible to colistin and nafcillin, paromomycin, spiramycin, and D,L-serine hydroxmate than the wild type. The spot assay, time kill assay and minimal inhibition concentration determination also indicated that the wild type could tolerate colistin better than the AB ΔemrB mutant. Finally, the increased expression levels of all emrB-like genes, including A1S_0775, A1S_0909, A1S_1772, and A1S_1799, in colistin resistance-induced A. baumannii further supported the possible involvement of the emrB genes in A. baumannii colistin resistance. Together, the Emr pump systems in A. baumannii contribute to adaptation to osmotic stress and resistance to colistin.

  19. Crystal Structure of Hcp from Acinetobacter baumannii: A Component of the Type VI Secretion System.

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    Federico M Ruiz

    Full Text Available The type VI secretion system (T6SS is a bacterial macromolecular machine widely distributed in Gram-negative bacteria, which transports effector proteins into eukaryotic host cells or other bacteria. Membrane complexes and a central tubular structure, which resembles the tail of contractile bacteriophages, compose the T6SS. One of the proteins forming this tube is the hemolysin co-regulated protein (Hcp, which acts as virulence factor, as transporter of effectors and as a chaperone. In this study, we present the structure of Hcp from Acinetobacter baumannii, together with functional and oligomerization studies. The structure of this protein exhibits a tight β barrel formed by two β sheets and flanked at one side by a short α-helix. Six Hcp molecules associate to form a donut-shaped hexamer, as observed in both the crystal structure and solution. These results emphasize the importance of this oligomerization state in this family of proteins, despite the low similarity of sequence among them. The structure presented in this study is the first one for a protein forming part of a functional T6SS from A. baumannii. These results will help us to understand the mechanism and function of this secretion system in this opportunistic nosocomial pathogen.

  20. Activity of Gallium Meso- and Protoporphyrin IX against Biofilms of Multidrug-Resistant Acinetobacter baumannii Isolates

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    David Chang

    2016-03-01

    Full Text Available Acinetobacter baumannii is a challenging pathogen due to antimicrobial resistance and biofilm development. The role of iron in bacterial physiology has prompted the evaluation of iron-modulation as an antimicrobial strategy. The non-reducible iron analog gallium(III nitrate, Ga(NO33, has been shown to inhibit A. baumannii planktonic growth; however, utilization of heme-iron by clinical isolates has been associated with development of tolerance. These observations prompted the evaluation of iron-heme sources on planktonic and biofilm growth, as well as antimicrobial activities of gallium meso- and protoporphyrin IX (Ga-MPIX and Ga-PPIX, metal heme derivatives against planktonic and biofilm bacteria of multidrug-resistant (MDR clinical isolates of A. baumannii in vitro. Ga(NO33 was moderately effective at reducing planktonic bacteria (64 to 128 µM with little activity against biofilms (≥512 µM. In contrast, Ga-MPIX and Ga-PPIX were highly active against planktonic bacteria (0.25 to 8 µM. Cytotoxic effects in human fibroblasts were observed following exposure to concentrations exceeding 128 µM of Ga-MPIX and Ga-PPIX. We observed that the gallium metal heme conjugates were more active against planktonic and biofilm bacteria, possibly due to utilization of heme-iron as demonstrated by the enhanced effects on bacterial growth and biofilm formation.

  1. The resistance and transmission mechanism of Acinetobacter baumannii isolates in a tertiary care hospital, China.

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    Sun, Fengjun; Ou, Qianyi; Wang, Qian; Feng, Wei; Qiu, Xuewen; Chen, Jianhong; Liu, Yao; Xia, Peiyuan

    2016-12-01

    The aim of this study was to analyse the resistance and epidemiological data of 117 Acinetobacter baumannii isolates from Southwest Hospital, Chongqing, China. Except for polymyxin B, tigecycline, minocycline, cefoperazone/sulbactam, amikacin and levofloxacin, the resistance rates of other antimicrobial agents were above 90%. All the clinical isolates had the blaOXA-51 gene and 114 isolates had the blaOXA-23 gene. Forty-nine isolates were found to contain the blaIMP-4 gene. PFGE data showed that 117 isolates were divided into 25 groups. Sixty-three (53.85%) were found to carry the class 1 integron, and the sequence analysis of the class 1 integron internal variable regions - five types, one of which had the blaIMP-4 gene. For the blaIMP-4 positive strain without class 1 integron, we found the flanking sequence had the TnpA gene. The result suggested that the resistance gene was widely distributed in our hospital; moreover, the modes of presence and transmission are different and complicated. The results of our study can improve the infection empirical treatment method and infection control programme.

  2. Antibacterial activity of a newly developed peptide-modified lysin against Acinetobacter baumannii and Pseudomonas aeruginosa

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    Hang eYang

    2015-12-01

    Full Text Available The global emergence of multidrug-resistant (MDR bacteria is a growing threat to public health worldwide. Natural bacteriophage lysins are promising alternatives in the treatment of infections caused by Gram-positive pathogens, but not Gram-negative ones, like Acinetobacter baumannii and Pseudomonas aeruginosa, due to the barriers posed by their outer membranes. Recently, modifying a natural lysin with an antimicrobial peptide was found able to break the barriers, and to kill Gram-negative pathogens. Herein, a new peptide-modified lysin (PlyA was constructed by fusing the cecropin A peptide residues 1–8 (KWKLFKKI with the OBPgp279 lysin and its antibacterial activity was studied. PlyA showed good and broad antibacterial activities against logarithmic phase A. baumannii and P. aeruginosa, but much reduced activities against the cells in stationary phase. Addition of outer membrane permeabilizers (EDTA and citric acid could enhance the antibacterial activity of PlyA against stationary phase cells. Finally, no antibacterial activity of PlyA could be observed in some bio-matrices, such as culture media, milk, and sera. In conclusion, we reported here a novel peptide-modified lysin with significant antibacterial activity against both logarithmic (without OMPs and stationary phase (with OMPs A. baumannii and P. aeruginosa cells in buffer, but further optimization is needed to achieve broad activity in diverse bio-matrices.

  3. Insights on the Horizontal Gene Transfer of Carbapenemase Determinants in the Opportunistic Pathogen Acinetobacter baumannii

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    Gabriela Jorge Da Silva

    2016-08-01

    Full Text Available Horizontal gene transfer (HGT is a driving force to the evolution of bacteria. The fast emergence of antimicrobial resistance reflects the ability of genetic adaptation of pathogens. Acinetobacter baumannii has emerged in the last few decades as an important opportunistic nosocomial pathogen, in part due to its high capacity of acquiring resistance to diverse antibiotic families, including to the so-called last line drugs such as carbapenems. The rampant selective pressure and genetic exchange of resistance genes hinder the effective treatment of resistant infections. A. baumannii uses all the resistance mechanisms to survive against carbapenems but production of carbapenemases are the major mechanism, which may act in synergy with others. A. baumannii appears to use all the mechanisms of gene dissemination. Beyond conjugation, the mostly reported recent studies point to natural transformation, transduction and outer membrane vesicles-mediated transfer as mechanisms that may play a role in carbapenemase determinants spread. Understanding the genetic mobilization of carbapenemase genes is paramount in preventing their dissemination. Here we review the carbapenemases found in A. baumannii and present an overview of the current knowledge of contributions of the various HGT mechanisms to the molecular epidemiology of carbapenem resistance in this relevant opportunistic pathogen.

  4. Imaging mass spectrometry for assessing temporal proteomics: analysis of calprotectin in Acinetobacter baumannii pulmonary infection.

    Science.gov (United States)

    Moore, Jessica L; Becker, Kyle W; Nicklay, Joshua J; Boyd, Kelli L; Skaar, Eric P; Caprioli, Richard M

    2014-04-01

    Imaging MS is routinely used to show spatial localization of proteins within a tissue sample and can also be employed to study temporal protein dynamics. The antimicrobial S100 protein calprotectin, a heterodimer of subunits S100A8 and S100A9, is an abundant cytosolic component of neutrophils. Using imaging MS, calprotectin can be detected as a marker of the inflammatory response to bacterial challenge. In a murine model of Acinetobacter baumannii pneumonia, protein images of S100A8 and S100A9 collected at different time points throughout infection aid in visualization of the innate immune response to this pathogen. Calprotectin is detectable within 6 h of infection as immune cells respond to the invading pathogen. As the bacterial burden decreases, signals from the inflammatory proteins decrease. Calprotectin is no longer detectable 96-144 h post infection, correlating to a lack of detectable bacterial burden in lungs. These experiments provide a label-free, multiplexed approach to study host response to a bacterial threat and eventual clearance of the pathogen over time.

  5. The contribution of nutrient metal acquisition and metabolism to Acinetobacter baumannii survival within the host

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    Brittany L Mortensen

    2013-12-01

    Full Text Available Acinetobacter baumannii is a significant contributor to intensive care unit (ICU mortality causing numerous types of infection in this susceptible ICU population, most notably ventilator-associated pneumonia. The substantial disease burden attributed to A. baumannii and the rapid acquisition of antibiotic resistance make this bacterium a serious health care threat. A. baumannii is equipped to tolerate the hostile host environment through modification of its metabolism and nutritional needs. Among these adaptations is the evolution of mechanisms to acquire nutrient metals that are sequestered by the host as a defense against infection. Although all bacteria require nutrient metals, there is diversity in the particular metal needs among species and within varying tissue types and bacterial lifecycles. A. baumannii is well-equipped with the metal homeostatic systems required for the colonization of a diverse array of tissues. Specifically, iron and zinc homeostasis is important for A. baumannii interactions with biotic surfaces and for growth within vertebrates. This review discusses what is currently known regarding the interaction of A. baumannii with vertebrate cells with a particular emphasis on the contributions of metal homeostasis systems. Overall, published research supports the utility of exploiting these systems as targets for the development of much-needed antimicrobials against this emerging infectious threat.

  6. Sheltering effect and indirect pathogenesis of carbapenem-resistant Acinetobacter baumannii in polymicrobial infection.

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    Liao, Yu-Ting; Kuo, Shu-Chen; Lee, Yi-Tzu; Chen, Chien-Pei; Lin, Shu-Wen; Shen, Li-Jiuan; Fung, Chang-Phone; Cho, Wen-Long; Chen, Te-Li

    2014-07-01

    The role of carbapenem-resistant Acinetobacter baumannii (CRAb) in polymicrobial infection remains elusive. Having observed the ability of CRAb to shelter other susceptible bacteria from carbapenem killing, we sought to determine the factors contributing to this sheltering effect by transforming different recombinant plasmids into recipient A. baumannii cells. The sheltering effects of CRAb were reproduced in recipient A. baumannii cells that highly expressed carbapenem-hydrolyzing class D β-lactamases (CHDLs) through their associated strong promoter. With the use of Western blot analysis and a bioassay, the highly expressed CHDLs were found to be extracellularly released and led to hydrolysis of carbapenem. The level of extracellular CHDLs increased after challenge with a higher concentration of CHDL substrates, such as carbapenem and ticarcillin. This increased CHDL may, in part, be attributed to cell lysis, as indicated by the presence of extracellular gyrase. In the planktonic condition, the sheltering effect for the cocultured susceptible bacteria might represent an indirect and passive effect of the CRAb self-defense mechanism, because coculture with the susceptible pathogen did not augment the amount of the extracellular CHDLs. Polymicrobial infection caused by CRAb and a susceptible counterpart exerted higher pathogenicity than monomicrobial infection caused by either pathogen alone in mice receiving carbapenem therapy. This study demonstrated that CHDL-producing CRAb appears to provide a sheltering effect for carbapenem-susceptible pathogens via the extracellular release of CHDLs and, by this mechanism, can enhance the pathogenesis of polymicrobial infection in the presence of carbapenem therapy.

  7. Factors influencing survival in patients with multidrug-resistant Acinetobacter baumannii infection

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    Mariana Lima Prata-Rocha

    2012-06-01

    Full Text Available Multidrug-resistant (MDR Acinetobacter baumannii (Acb is a rapidly emerging pathogen in healthcare settings. The aim of this study was to evaluate the predictors of poor outcome in patients with MDR Acb. This is the first report documenting factors influencing survival in patients with MDR Acb in this tertiary hospital. This study is a prospective of the hospital epidemiology database. A total of 73 patients with 84 Acb isolates were obtained between August 2009 and October 2010 in this hospital. In the present study, the 30-day mortality rate was 39.7%. Of 84 Acb isolates, 50 (59% were MDR, nine (11% were pan-resistant, and 25 (30% were non-MDR. The non-MDR isolates were used as the control group. The factors significantly associated with multidrug resistance included previous surgeries, presence of comorbidity (renal disease, use of more than two devices, parenteral nutrition, and inappropriate antimicrobial therapy. Significant predictors of 30-day mortality in the univariate analysis included pneumonia, diabetes mellitus, renal disease, use of more than two devices, and inappropriate antimicrobial therapy administered within two days of the onset of infection. The factors associated with mortality in patients with MDR Acb infection in this study were: age > 60 years, pneumonia, diabetes mellitus, renal disease, use of more than two invasive procedures, and inappropriate antimicrobial therapy. Vigilance is needed to prevent outbreaks of this opportunistic and deadly pathogen.

  8. Resistance and integron characterization of Acinetobacter baumannii in a teaching hospital in Chongqing, China

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    C. Huang

    2015-11-01

    Full Text Available A total of 189 Acinetobacter baumannii isolates were collected in 2011 from a teaching hospital in Chongqing, China. Susceptibility data showed strains carrying integrons were significantly more resistant to all tested antibiotics that strains lacking integrons. Five types of gene cassettes belonging to class I integrons were identified in this study, and for the first time two types of gene cassettes belonging to class II integrons are reported. Most of the cassettes belong to a class I integron (136/144 encoding arr3, aacA4, dfrA17, aadA5, aadB, cat, blaOXA10, aadA1, aadA2, dfrA and aacC1. Isolates contained a class I gene cassette; AadA2-HP-dfrA was the prevalent strain in this hospital. A class II integron was detected in eight strains, which contained the type IV fimbriae expression regulatory gene pilR and sulfate adenylyltransferase, suggesting a possible role in multidrug resistance. The major epidemic strains from intensive care unit patients belong to international clone 2. In conclusion, the presence of integrons was significantly associated with multiple drug resistance of A. baumannii in this hospital, and class I integron isolates bearing AadA2-HP-dfrA were the prevalent strain in this hospital.

  9. Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery

    Science.gov (United States)

    Dong, Hao; Xia, Wenjie; Dong, Honghong; She, Yuehui; Zhu, Panfeng; Liang, Kang; Zhang, Zhongzhi; Liang, Chuanfu; Song, Zhaozheng; Sun, Shanshan; Zhang, Guangqing

    2016-01-01

    Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9, and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR. PMID:27872613

  10. Natural genetic transformation in Acinetobacter sp. BD413 Biofilms: introducing natural genetic transformation as a tool for bioenhancement of biofilm reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickx, L.

    2002-07-01

    This study focussed on the localization and quantification of natural genetic transformation using neutral and disadvantageous genes in monoculture biofilms to investigate gene transfer and expression of the transferred genes in the absence of a selective advantage. Data obtained by this investigation were regarded as initial steps for evaluating the applicability of adding catabolic traits into the indigenous bacterial community of biofilm reactors by in situ natural genetic transformation. Because Acinetobacter spp. strains are readily found in waste water treatment plants and because Acinetobacter sp. BD413 possesses a high effective level of competence, natural genetic transformation was investigated in monoculture Acinetobacter sp. BD413 biofilms. The genes used for transformation encoded for the green fluorescent protein (GFP) and its variants. Monitoring of transformation events were performed with the use of automated confocal laser scanning microscopy (CLSM) and semi automated digital image processing and analysis. (orig.)

  11. A metallo-keratinase from a newly isolated Acinetobacter sp. R-1 with low collagenase activity and its biotechnological application potential in leather industry.

    Science.gov (United States)

    Zhang, Rong-Xian; Gong, Jin-Song; Zhang, Dan-Dan; Su, Chang; Hou, Ying-Shuo; Li, Heng; Shi, Jin-Song; Xu, Zheng-Hong

    2016-01-01

    Microbial keratinase is a well-recognized enzyme that can specifically degrade insoluble keratins. A keratinase-producing bacterium was isolated from a duck ranch soil and identified as Acinetobacter sp. R-1 based on the biochemical characteristics and 16S rDNA gene sequencing. It showed high keratinase activity and low collagenase activity. The keratinase was purified to electrophoretic homogeneity with 6.69% recovery, 2.68-fold purification and an estimated molecular weight of 25 kDa. Additionally, the keratinase showed optimal activity at 50 °C and pH11. Keratinase activity of Acinetobacter sp. significantly increased in the presence of Li(+), Na(+), and Ca(2+), while it was completely inhibited by EDTA, indicating it was a metallo-keratinase. Moreover, the crude keratinase from Acinetobacter sp. R-1 could thoroughly depilate goat skin and simultaneously modify the wool surface, which indicated its applicable potential in leather and textile industries.

  12. Mechanism of clinical antibiotic-resistant Acinetobacter baumannii%鲍曼不动杆菌对临床抗菌药物耐药机制

    Institute of Scientific and Technical Information of China (English)

    赵媛媛; 阎锡新

    2010-01-01

    Acinetobacter baumannii is one of the most common pathogens in nosocomial infection.In recent years,multi-drug resistant and pan-drug resistant Acinetobacter baumannii have been increasing,which seriously threatens clinical therapy. This article reviews the clinical antibiotic-resistant mechanisms of Acinetobacter baumannii.%鲍曼不动杆菌是医院感染最常见的病原菌之一.近年来,多重耐药及泛耐药鲍曼不动杆菌感染日渐增多,对临床构成严重威胁.本文就鲍曼不动杆菌对临床主要使用的抗菌药物的耐药机制作一综述.

  13. Colistin bladder instillation, an alternative way of treating multi-resistant Acinetobacter urinary tract infection: a case series and review of literature.

    Science.gov (United States)

    Giua, R; Pedone, C; Cortese, L; Antonelli Incalzi, R

    2014-02-01

    The multiresistant Acinetobacter species bacteria are frequently involved in urinary or respiratory tract infections, and one of the most effective drugs, colistine, is associated with significant nephrotoxicity and neurotoxicity. Given that very high concentrations of colistine into biological fluids are safe for the human organism, attempts have been made at delivering the drug topically, by aerosol, or, occasionally, intratechally or intraventricularly for meningitis. These topical treatments could eradicate the Pseudomonas sp. from the lung of patients with cystic fibrosis or bronchiectasis and the Acinetobacter baumannii from lung and meninges. However, only one case of colistin topic treatment in urinary tract infection is described. We report a case series of three patients successfully undergone colistin bladder instillations for multi drug resistant Acinetobacter urinary tract infection, and we review the literature about colistin topic treatment.

  14. Dissemination of blaOXA-23 in Acinetobacter spp. in China: main roles of conjugative plasmid pAZJ221 and transposon Tn2009.

    Science.gov (United States)

    Liu, Li-Lin; Ji, Shu-Juan; Ruan, Zhi; Fu, Ying; Fu, Yi-Qi; Wang, Yan-Fei; Yu, Yun-Song

    2015-04-01

    Production of the OXA-23 carbapenemase is the most common reason for the increasing carbapenem resistance in Acinetobacter spp. This study was conducted to reveal the genetic basis of blaOXA-23 dissemination in Acinetobacter spp. in China. A total of 63 carbapenem-resistant OXA-23-producing Acinetobacter sp. isolates, representing different backgrounds, were selected from 28 hospitals in 18 provinces for this study. Generally, two patterns of plasmids carrying blaOXA-23 were detected according to S1-nuclease pulsed-field gel electrophoresis and Southern blot hybridization. A ca. 78-kb plasmid, designated pAZJ221, was found in 23 Acinetobacter baumannii and three Acinetobacter nosocomialis isolates, while a novel ca. 50-kb plasmid was carried by only two other A. baumannii isolates. Three of these isolates had an additional copy of blaOXA-23 on the chromosome. Transformation of the two plasmids succeeded, but only pAZJ221 was conjugative. Plasmid pAZJ221 was sequenced completely and found to carry no previously known resistance genes except blaOXA-23. The blaOXA-23 gene of the remaining 35 isolates was chromosome borne. The blaOXA-23 genetic environments were correlated with Tn2009 in 57 isolates, Tn2008 in 5 isolates, and Tn2006 in 1 isolate. The MIC values for the carbapenems with these isolates were not significantly associated with the genomic locations or the copy numbers of blaOXA-23. Overall, these observations suggest that the plasmid pAZJ221 and Tn2009 have effectively contributed to the wide dissemination of blaOXA-23 in Acinetobacter spp. in China and that horizontal gene transfer may play an important role in dissemination of the blaOXA-23 gene.

  15. 101株鲍曼不动杆菌的耐药性分析%Analysis of drug resistance of acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    王仲书; 李玉梅; 王灿灿

    2011-01-01

    目的 了解鲍曼不动杆菌的临床分布及其对常用抗生素的耐药状况,为有效的临床治疗和医院感染控制提供实验室依据.方法 对2008年4月~2009年6月间某院分离出的101株鲍曼不动杆菌通过微量稀释法进行MIC测定.结果101株鲍曼不动杆菌大多分离自痰液,主要来自于ICU病房.鲍曼不动杆菌对复方新诺明耐药率最高,为91%,依次是环丙沙星89%,庆大霉素86%、头孢噻肟86%等.结论:我院鲍曼不动杆菌耐药情况严重,治疗首选碳青霉烯类抗生素,其次可选用替卡西林/克拉维酸、头孢哌酮/舒巴坦.%Objective To investigate the distribution and drug resistance of Acinetobacter baumanii. Methods The minimum inhibitory concentrations (MIC) of 101 acinetobacter baumannii isolated were measured by microdilution method. Results 101 Acinetobacter baummanii were mainly isolated from ICU, and most of them were from sputum. Antimicrobial susceptibility tests showed the resistant rate of Acinetobacter baumannii to Trimethoprim-Sulfamethoxazole was the highest (91%), folio wed by gentamicin (86%), cefotaxime (86%). Conclusion The drug resistance of Acinetobacter baummanii is serious. Carbapenem is the preferred antibacterial therapy for Acinetobacter baumannii.

  16. Isolation of Diesel Degrading Strain Acinetobacter sp. AK5 and Its Degrading Performance%柴油降解菌Acinetobacter sp. AK5的筛选及其降解性能研究

    Institute of Scientific and Technical Information of China (English)

    徐晓宇; 陈敬华

    2014-01-01

    从污水处理厂的活性污泥中分离到一株柴油降解菌,通过生理生化鉴定和16S rDNA序列分析,鉴定该菌为不动杆菌Acinetobacter sp. AK5。检测了不同pH值、NaCl浓度、培养时间和各种柴油浓度下Acinertobacter sp. AK5的柴油降解情况。结果表明,该菌的最适生长初始pH值为5-9,适合NaCl浓度为3%-4%,柴油浓度为5 g/L时,该菌7 d柴油降解率可达99%,柴油浓度为20 g/L时,7 d柴油降解率也可达67%。AK5在人工海水培养基中及无机盐培养基中生长状态良好,在海水和淡水石油污染的生物修复中具有很好的应用前景。%A diesel degradable bacterial strain was isolated from activated sludge and identified as Acinetobacter sp. AK5 through physiological, biochemical identification and 16S rDNA sequence analysis. Experiments of the different pH values, NaCl concentrations, culture time and diesel concentrations were detected to evaluate the diesel degradability by Acinetobacter sp. AK5. The results show that the optimal initial pH scope for the bacterial growth is from 5 to 9, the optimum NaCl concentrations is between 3%and 4%. When the diesel concentration is 5 g/L, the 7 d diesel degradation rate can reach 99%, while when the concentration of diesel is 20 g/L, 7 d diesel degradation rate can be 67%. The Acinetobacter sp. AK5 can grow well in artificial seawater medium and inorganic salt culture medium, therefore it has promising application prospect in seawater and freshwater oil pollution treatment.

  17. Characterization of a novel plasmid type and various genetic contexts of bla OXA-58 in Acinetobacter spp. from multiple cities in China.

    Directory of Open Access Journals (Sweden)

    Yiqi Fu

    Full Text Available BACKGROUND/OBJECTIVE: Several studies have described the epidemiological distribution of blaOXA-58-harboring Acinetobacter baumannii in China. However, there is limited data concerning the replicon types of blaOXA-58-carrying plasmids and the genetic context surrounding blaOXA-58 in Acinetobacter spp. in China. METHODOLOGY/PRINCIPAL FINDINGS: Twelve non-duplicated blaOXA-58-harboring Acinetobacter spp. isolates were collected from six hospitals in five different cities between 2005 and 2010. The molecular epidemiology of the isolates was carried out using PFGE and multilocus sequence typing. Carbapenemase-encoding genes and plasmid replicase genes were identified by PCR. The genetic location of blaOXA-58 was analyzed using S1-nuclease method. Plasmid conjugation and electrotransformation were performed to evaluate the transferability of blaOXA-58-harboring plasmids. The genetic structure surrounding blaOXA-58 was determined by cloning experiments. The twelve isolates included two Acinetobacter pittii isolates (belong to one pulsotype, three Acinetobacter nosocomialis isolates (belong to two pulsotypes and seven Acinetobacter baumannii isolates (belong to two pulsotypes/sequence types. A. baumannii ST91 was found to be a potential multidrug resistant risk clone carrying both blaOXA-58 and blaOXA-23. blaOXA-58 located on plasmids varied from ca. 52 kb to ca. 143 kb. All plasmids can be electrotransformed to A. baumannii recipient, but were untypeable by the current replicon typing scheme. A novel plasmid replicase named repAci10 was identified in blaOXA-58-harboring plasmids of two A. pittii isolates, three A. nosocomialis isolates and two A. baumannii isolates. Four kinds of genetic contexts of blaOXA-58 were identified. The transformants of plasmids with structure of IS6 family insertion sequence (ISOur1, IS1008 or IS15-ΔISAba3-like element-blaOXA-58 displayed carbapenem nonsusceptible, while others with structure of intact ISAba3-like element

  18. Impacts of some divalent cations on periplasmic nitrate reductase and dehydrogenase enzymes of Escherichia, Pseudomonas and Acinetobacter species

    Directory of Open Access Journals (Sweden)

    Christian E. Nwanyanwu

    2008-08-01

    Full Text Available The impacts of Hg2+, Cd2+ and Zn2+ on the activities of periplasmic nitrate reductase (NAP and dehydrogenase (DHA enzymes of three organisms isolated from soil and sediment-water interface were analysed in liquid culture studies. NAP and DHA activities were estimated from nitrite and triphenyl formazan were produced respectively after 4h incubation at 28 ± 2oC. Hg2+ completely inhibited NAP activity in Escherichia and Pseudomonas spp at all the concentrations (0.2 – 1mM while progressive inhibitions of NAP activity were observed in Escherichia and Pseudomonas spp with increasing concentrations of Zn2+ and Cd2+. Both metals were stimulatory to NAP of Acinetobacter sp at 0.2 – 1mM. Apart from stimulation of DHA activity by Zn2+ (0.2 – 1mM in Escherichia sp, Cd2+ (0.4 -1.0mM in Acinetobacter sp and (1.0mM in Pseudomonas sp, all the metals progressively inhibited DHA activities in the three organisms. In Escherichia sp, the activities of the two enzymes were negatively correlated on exposure to Zn2+ (r = -0.91 and positively correlated (r = >0.90 on exposure to Cd2+ and Hg2+. Based on IC50 values of the metals for the DHA and NAP enzymes, the most resistant of the three organisms were Escherichia sp and Acinetobacter sp respectively. Quantitatively, NAP with its lower IC50 values than DHA was a more sensitive toxicity measure for Hg2+ in all the organisms. The sensitivity of microbial metabolic enzymes to the toxic effects of metals varies with the type of enzyme, metal and the microorganism involved.

  19. Characterization and upregulation of bifunctional phosphoglucomutase/phosphomannomutase enzyme in an exobiopolymer overproducing strain of Acinetobacter haemolyticus.

    Science.gov (United States)

    Kaur, Taranpreet; Ghosh, Moushumi

    2015-12-01

    Several members of the Acinetobacter spp. produce exobiopolymer (EBP) of considerable biotechnological interest. In a previous study, we reported phosphate removal capacity of EBP produced by Acinetobacter haemolyticus. Insertional mutagenesis was attempted to develop EBP-overproducing strains of A. haemolyticus and mutant MG606 was isolated. In order to understand the underlying mechanism of overproduction, the EBP overproducing mutant MG606 was analyzed and compared with the wild type counterpart for its key EBP synthetic enzymes. The EBP produced by MG606 mutant was 650 mg/L compared to 220 mg/L in its wild type counterpart. Significantly high (p0.05). The up-regulation of PGM/PMM expression in mutant was further confirmed by real time reverse transcriptase (RT)-PCR of PGM/PMM transcripts. The optimal conditions for PGM/PMM activity were found to be 35 °C and pH 7.5; PGM/PMM activity was inhibited by ions such as lithium, zinc, nickel. Further, incubation of cells with a PGM inhibitor (lithium) resulted in a concentration-dependent decrease in EBP production further confirming the role of PGM/PMM overexpression in enhanced EBP production by the mutant. Overall the results of our study indicate a key role of PGM/PMM in enhanced EBP production, as evident from enhanced enzyme activity, increased PGM/PMM transcripts and reduction in EBP synthesis by a PGM inhibitor. We envisage a potential exploitation of the insights so obtained to effectively engineer strains of Acinetobacter for overproducing phosphate binding EBP.

  20. Risk factors and outcome for colistin-resistant Acinetobacter nosocomialis bacteraemia in patients without previous colistin exposure.

    Science.gov (United States)

    Wang, Y-C; Lee, Y-T; Yang, Y-S; Chen, C-T; Chiu, C-H; Yin, T; Kuo, S-C; Chen, T-L; Lin, J-C; Wang, F-D; Fung, C-P; Chang, F-Y

    2015-08-01

    The clinical characteristics of patients with colistin-resistant Acinetobacter baumannii bacteraemia have been documented, but those of patients with bacteraemia caused by other Acinetobacter species remain unknown. Previous exposure to colistin has been shown to be associated with the emergence of colistin resistance, but may be not the only predisposing factor. In the current study, we highlight the risk and outcome of patients without previous exposure to colistin who acquired colistin-resistant Acinetobacter nosocomialis (ColRAN) bacteraemia. This 11-year single-centre retrospective study analysed 58 patients with ColRAN bacteraemia and 213 patients with colistin-susceptible A. nosocomialis (ColSAN) bacteraemia. Antimicrobial susceptibilities were determined with an agar dilution method. The clonal relationship of ColRAN isolates was determined with pulsed-field gel electrophoresis. A conjugation mating-out assay was conducted to delineate the potential transfer of colistin resistance genes. Multivariable analysis was performed to evaluate the risk factors for ColRAN bacteraemia. Chronic obstructive pulmonary disease (COPD) was independently associated with ColRAN bacteraemia (OR 3.04; 95% CI 1.45-6.37; p 0.003). Patients with ColRAN bacteraemia had higher APACHE II scores, but the two groups showed no significant differences in 14-day mortality (10.3% vs. 10.3%) or 28-day mortality (15.5% vs. 15.0%). ColRAN isolates had greater resistance than ColSAN isolates to all antimicrobial agents except for ciprofloxacin (0% vs. 6.6%). There were 16 different ColRAN pulsotypes, and two major clones were found. Colistin resistance did not transfer to colistin-susceptible A. baumannii or A. nosocomialis. These results show that COPD is an independent risk factor for acquisition of ColRAN bacteraemia. The mortality rates were similar between patients with ColRAN and ColSAN bacteraemia.