WorldWideScience

Sample records for acinetobacter baumannii isolates

  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. 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...

  3. 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.

  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. 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.

  6. Antibiotic Resistance in Acinetobacter Baumannii Strains Isolated from Nosocomial Infections

    National Research Council Canada - National Science Library

    Pinar Korkmaz

    2016-01-01

    ...%. In this study, it was aimed to assess the frequency of Acinetobacter baumannii species which were considered to be causative agents of nosocomial infection and their resistance to antimicrobial...

  7. 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.

  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. Dissemination of multidrug-resistant, class 1 integron-carrying Acinetobacter baumannii isolates in Taiwan

    National Research Council Canada - National Science Library

    Huang, L.-Y; Chen, T.-L; Lu, P.-L; Tsai, C.-A; Cho, W.-L; Chang, F.-Y; Fung, C.-P; Siu, L. K

    2008-01-01

    In this study, 283 multidrug-resistant Acinetobacter baumannii (MDR-AB) bloodstream isolates were collected between 1996 and 2004, from three teaching hospitals located in different regions of Taiwan...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

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

    Science.gov (United States)

    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)).

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

    Science.gov (United States)

    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

  17. 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.

  18. [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.

  19. 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.

  20. Identification of OXA-23 carbapenemases: novel variant OXA-239 in Acinetobacter baumannii ST758 clinical isolates in Mexico

    Science.gov (United States)

    Tamayo-Legorreta, E M; Garza-Ramos, U; Barrios-Camacho, H; Sanchez-Perez, A; Galicia-Paredes, A; Meza-Chavez, A; Silva-Sanchez, J

    2014-01-01

    A collection of 15 carbapenem-resistance Acinetobacter baumannii clinical isolates was analysed on two tertiary hospitals in Mexico. The OXA-51 was identified in all isolates, followed by OXA-239 and OXA-58; OXA-239 is described as a new OXA-23-like allele. These carbapenemases were identified on four clonal groups, distributed between two neighbouring hospitals. Acinetobacter baumannii is poorly studied in Mexico; this situation urges the implementation of strategies to prevent its dissemination. PMID:25566396

  1. Identification of OXA-23 carbapenemases: novel variant OXA-239 in Acinetobacter baumannii ST758 clinical isolates in Mexico

    Directory of Open Access Journals (Sweden)

    E.M. Tamayo-Legorreta

    2014-11-01

    Full Text Available A collection of 15 carbapenem-resistance Acinetobacter baumannii clinical isolates was analysed on two tertiary hospitals in Mexico. The OXA-51 was identified in all isolates, followed by OXA-239 and OXA-58; OXA-239 is described as a new OXA-23-like allele. These carbapenemases were identified on four clonal groups, distributed between two neighbouring hospitals. Acinetobacter baumannii is poorly studied in Mexico; this situation urges the implementation of strategies to prevent its dissemination.

  2. 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.

  3. Characterisation of successive Acinetobacter baumannii isolates from a deceased haemophagocytic lymphohistiocytosis patient.

    Science.gov (United States)

    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.

  4. Aptamer-nanobody based ELASA for specific detection of Acinetobacter baumannii isolates.

    Science.gov (United States)

    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.

  5. 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...

  6. Diversity of polymyxin resistance mechanisms among Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Girardello, Raquel; Visconde, Marina; Cayô, Rodrigo; Figueiredo, Regina Célia Bressan Queiroz de; Mori, Marcelo Alves da Silva; Lincopan, Nilton; Gales, Ana Cristina

    2017-01-01

    Polymyxins have become drugs of last resort for treatment of multi-drug resistant (MDR) Gram-negative infections. However, the mechanisms of resistance to this compound have not been completely elucidated. In this study, we evaluated the mechanisms of resistance to this antimicrobial in two A. baumannii clinical isolates, respectively, susceptible (A027) and resistant (A009) to polymyxin B before and after polymyxin B exposure (A027(ind) and A009(ind)). The pmrAB and lpxACD were sequenced and their transcriptional levels were analyzed by qRT-PCR. The bacterial cell morphology was evaluated by transmission electronic microscopy (TEM) and the membrane potential was measured using Zeta-potential analyzer. The virulence of strains was studied using a Caenorhabditis elegans model. Both clinical isolates exhibited an elevation of the polymyxin B MIC after exposure to this compound. On the other hand, A027(ind) showed decreased values of MIC for β-lactams, aminoglycosides, vancomycin, teicoplanin, oxacillin and erythromycin. A027(ind) harbored two mutations in pmrB and the ISAba125 disrupting the lpxA. In contrast, A009(ind) strain exhibited increase of pmrB transcriptional level, after polymyxin B exposure, despite the absence of mutations in the pmrAB genes. The TEM images revealed a thicker and more electron-dense peptidoglycan layer for A009 than that of A027. The exposure to polymyxin B induced a strong condensation and darkening of intracellular material, mainly in A009(ind). In addition, the surface charge of A009 was significantly less negative than the one of A027. Using the C. elegans model, only A027(ind) strain showed a reduction on virulence. The diversity of polymyxin B resistance mechanisms among A. baumannii strains evaluated in this study confirms the complexity of these mechanisms, which may vary depending of the background of each strain.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Antibacterial activity of Hibiscus sabdariffa L. calyces against hospital isolates of multidrug resistant Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    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.

  12. Isolation and characterization of Acinetobacter baumannii recovered from Campylobacter selective medium.

    Directory of Open Access Journals (Sweden)

    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.

  13. 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

  14. Clinical isolates of Acinetobacter baumannii from a Portuguese hospital: PFGE characterization, antibiotic susceptibility and biofilm-forming ability.

    Science.gov (United States)

    Duarte, Andreia; Ferreira, Susana; Almeida, Sofia; Domingues, Fernanda C

    2016-04-01

    Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections that in addition has shown an increasing resistance to antibiotics. In this work the genetic diversity of A. baumannii isolates from a Portuguese hospital, their antibiotic resistance profiles and ability to form biofilms was studied. Seventy-nine clinical A. baumannii isolates were characterized by pulsed-field gel electrophoresis (PFGE) with 9 different PFGE profiles being obtained. Concerning the antimicrobial susceptibility, all A. baumannii isolates were resistant to 12 of the 17 tested antibiotics and classified as multidrug-resistant (MDR). In addition, 74.7% of the isolates showed biofilm formation ability, however no statistical significance with antibiotic resistance was observed. In contrast, urine samples isolates were more likely to form biofilms than strains isolated from other sources. Our findings highlight the high number of MDR A. baumannii isolates and the importance of the formation of biofilms as a potential virulence factor.

  15. [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.

  16. Distribution and expression of the Ade multidrug efflux systems in Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Pagdepanichkit, Sirawit; Tribuddharat, Chanwit; Chuanchuen, Rungtip

    2016-09-01

    One hundred Acinetobacter baumannii clinical isolates were examined for inhibitory effect of reserpine and carbonyl cyanide m-chlorophenylhydrazone (CCCP) on the antimicrobial susceptibility and expression of 4 resistant-nodulation-cell division (RND)-type multidrug efflux systems, including AdeABC, AdeDE, AdeIJK, and AdeFGH, using RT-PCR. Ten A. baumannii isolates expressing AdeABC, AdeIJK, or AdeFGH were randomly selected for determination of transcription level and regulatory mutations. While all the isolates were resistant to multiple drugs, the reserpine and CCCP experiment showed that the multidrug resistance phenotype in most A. baumannii isolates was associated with efflux pumps. Most isolates expressed at least one of the RND-type efflux pumps tested (97%). AdeIJK expression was most common (97%), but none of the isolates produced AdeDE. Fifty-two percent of the A. baumannii isolates simultaneously produced up to 3 RND-type efflux systems (i.e., AdeABC, AdeFGH, and AdeIJK). No good correlation between the expression of RND-type efflux pumps and the type of antimicrobial resistance was observed. Overexpression of AdeABC, AdeIJK, and AdeFGH was not always related to the presence of mutations in their corresponding regulatory genes. This study highlights (i) the universal presence of the RND-type efflux pumps with variable levels of expression level among the A. baumannii in this collection and (ii) the complexity of their regulation of expression.

  17. Systematic Review of Antimicrobial Resistance of Clinical Acinetobacter baumannii Isolates in Iran: An Update.

    Science.gov (United States)

    Razavi Nikoo, Hadi; Ardebili, Abdollah; Mardaneh, Jalal

    2017-01-13

    Treatment of Acinetobacter baumannii has become a medical challenge because of the increasing incidence of multiresistant strains and a lack of viable treatment alternatives. This systematic review attempts to investigate the changes in resistance of A. baumannii to different classes of antibiotics in Iran, with emphasis on the antimicrobial activity of polymyxin B (PMB) and colistin (COL). Biomedical databases were searched for English-published articles evaluating microbiological activity of various antimicrobial agents, including PMB and COL. Then, the available data were extracted and analyzed. Thirty-one studies, published from 2009 to 2015, were identified which contain data for 3,018 A. baumannii clinical isolates. With the exception of polymyxins and tigecycline (TIG), there was a high rate of resistance to various groups of antibiotics, including carbapenems. The minimum inhibitory concentration (MIC) ranges for PMB and COL on A. baumannii isolates tested were 0.12-64 μg/ml and 0.001-128 μg/ml, respectively. Polymyxins showed adequate activity with no significant trends in the resistance rate during most of the study period. The incidence of resistance to TIG was estimated low from 2% to 38.4% among the majority of A. baumannii. The present systematic review of the published literatures revealed that multidrug-resistant (including carbapenem-resistant) strains of A. baumannii have increased in Iran. In these circumstances, the older antibiotics, such as COL or PMB, preferably in combination with other antimicrobials (rifampicin, meropenem), could be considered as the therapeutic solution against the healthcare-associated infections. Designing rational dosage regimens for patients to maximize the antimicrobial activity and minimize the emergence and prevalence of resistance is recommended.

  18. Acinetobacter baumannii in intensive care unit: A novel system to study clonal relationship among the isolates

    Directory of Open Access Journals (Sweden)

    Leonardis Francesca

    2008-06-01

    Full Text Available Abstract Background The nosocomial infections surveillance system must be strongly effective especially in highly critic areas, such as Intensive Care Units (ICU. These areas are frequently an epidemiological epicentre for transmission of multi-resistant pathogens, like Acinetobacter baumannii. As an epidemic outbreak occurs it is very important to confirm or exclude the genetic relationship among the isolates in a short time. There are several molecular typing systems used with this aim. The Repetitive sequence-based PCR (REP-PCR has been recognized as an effective method and it was recently adapted to an automated format known as the DiversiLab system. Methods In the present study we have evaluated the combination of a newly introduced software package for the control of hospital infection (VIGI@ct with the DiversiLab system. In order to evaluate the reliability of the DiversiLab its results were also compared with those obtained using f-AFLP. Results The combination of VIGI@ct and DiversiLab enabled an earlier identification of an A. baumannii epidemic cluster, through the confirmation of the genetic relationship among the isolates. This cluster regards 56 multi-drug-resistant A. baumannii isolates from several specimens collected from 13 different patients admitted to the ICU in a ten month period. The A. baumannii isolates were clonally related being their similarity included between 97 and 100%. The results of the DiversiLab were confirmed by f-AFLP analysis. Conclusion The early identification of the outbreak has led to the prompt application of operative procedures and precautions to avoid the spread of pathogen. To date, 6 months after the last A. baumannii isolate, no other related case has been identified.

  19. 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

  20. Emergence and clonal dissemination of carbapenem-hydrolysing OXA-58-producing Acinetobacter baumannii isolates in Bolivia.

    Science.gov (United States)

    Sevillano, Elena; Fernández, Elena; Bustamante, Zulema; Zabalaga, Silvia; Rosales, Ikerne; Umaran, Adelaida; Gallego, Lucía

    2012-01-01

    Acinetobacter baumannii is an emerging multidrug-resistant pathogen and very little information is available regarding its imipenem resistance in Latin American countries such as Bolivia. This study investigated the antimicrobial resistance profile of 46 clinical strains from different hospitals in Cochabamba, Bolivia, from March 2008 to July 2009, and the presence of carbapenemases as a mechanism of resistance to imipenem. Isolates were obtained from 46 patients (one isolate per patient; 30 males,16 females) with an age range of 1 day to 84 years, and were collected from different sample types, the majority from respiratory tract infections (17) and wounds (13). Resistance to imipenem was detected in 15 isolates collected from different hospitals of the city. These isolates grouped into the same genotype, named A, and were resistant to all antibiotics tested including imipenem, with susceptibility only to colistin. Experiments to detect carbapenemases revealed the presence of the OXA-58 carbapenemase. Further analysis revealed the location of the bla(OXA-58) gene on a 40 kb plasmid. To our knowledge, this is the first report of carbapenem resistance in A. baumannii isolates from Bolivia that is conferred by the OXA-58 carbapenemase. The presence of this gene in a multidrug-resistant clone and its location within a plasmid is of great concern with regard to the spread of carbapenem-resistant A. baumannii in the hospital environment in Bolivia.

  1. Multiple drug resistant carbapenemases producing Acinetobacter baumannii isolates harbours multiple R-plasmids

    Directory of Open Access Journals (Sweden)

    Rajagopalan Saranathan

    2014-01-01

    Full Text Available Background & objectives: The nosocomial human pathogen Acinetobacter baumannii has high propensity to develop resistance to antimicrobials and to become multidrug resistant (MDR, consequently complicating the treatment. This study was carried out to investigate the presence of resistant plasmids (R-plasmids among the clinical isolates of A. baumannii. In addition, the study was performed to check the presence of common β-lactamases encoding genes on these plasmids. Methods: A total of 55 clinical isolates of A. baumannii were included in the study and all were subjected to plasmid DNA isolation, followed by PCR to check the presence of resistance gene determinants such as blaOXA-23 , blaOXA-51, blaOXA-58 and blaIMP-1 on these plasmids that encode for oxacillinase (OXA and metallo-β-lactamase (MBL type of carbapenemases. Plasmid curing experiments were carried out on selected isolates using ethidium bromide and acridine orange as curing agents and the antibiotic resistance profiles were evaluated before and after curing. Results: All the isolates were identified as A. baumannii by 16SrDNA amplification and sequencing. Plasmid DNA isolated from these isolates showed the occurrence of multiple plasmids with size ranging from 500bp to ≥ 25 kb. The percentage of blaOXA-51 and blaOXA-23 on plasmids were found to be 78 and 42 per cent, respectively and 20 isolates (36% carried blaIMP-1 gene on plasmids. Significant difference was observed in the antibiograms of plasmid cured isolates when compared to their parental ones. The clinical isolates became susceptible to more than two antibiotic classes after curing of plasmids indicating plasmid borne resistance. Interpretation & conclusions: Our study determined the plasmid mediated resistance mechanisms and occurrence of different resistance genes on various plasmids isolated from MDR A. baumannii. The present findings showed the evidence for antibiotic resistance mediated through multiple plasmids in

  2. Isolation and Characterization of a Virulent Bacteriophage AB1 of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Jia Shiru

    2010-04-01

    Full Text Available Abstract Background Acinetobacter baumannii is an emerging nosocomial pathogen worldwide with increasing prevalence of multi-drug and pan-drug resistance. A. baumannii exists widely in natural environment, especially in health care settings, and has been shown difficult to be eradicated. Bacteriophages are often considered alternative agent for controlling bacterial infection and contamination. In this study, we described the isolation and characterization of one virulent bacteriophage AB1 capable of specifically infecting A. baumannii. Results A virulent bacteriophage AB1, specific for infecting a clinical strain A. baumannii KD311, was first isolated from marine sediment sample. Restriction analysis indicated that phage AB1 was a dsDNA virus with an approximate genome size of 45.2 kb to 46.9 kb. Transmission electron microscopy showed that phage AB1 had an icosahedral head with a non-contractile tail and collar or whisker structures, and might be tentatively classified as a member of the Siphoviridae family. Proteomic pattern of phage AB1, generated by SDS-PAGE using purified phage particles, revealed five major bands and six minor bands with molecular weight ranging from 14 to 80 kilo-dalton. Also determined was the adsorption rate of phage AB1 to the host bacterium, which was significantly enhanced by addition of 10 mM CaCl2. In a single step growth test, phage AB1 was shown having a latent period of 18 minutes and a burst size of 409. Moreover, pH and thermal stability of phage AB1 were also investigated. At the optimal pH 6.0, 73.2% of phages survived after 60 min incubation at 50°C. When phage AB1 was used to infect four additional clinical isolates of A. baumannii, one clinical isolate of Stenotrophomonas maltophilia, and Pseudomonas aeruginosa lab strains PAK and PAO1, none of the tested strains was found susceptible, indicating a relatively narrow host range for phage AB1. Conclusion Phage AB1 was capable of eliciting efficient lysis

  3. Emergence of Carbapenem-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Clinical Isolates Collected from Some Libyan Hospitals.

    Science.gov (United States)

    Mathlouthi, Najla; Areig, Zaynab; Al Bayssari, Charbel; Bakour, Sofiane; Ali El Salabi, Allaaeddin; Ben Gwierif, Salha; Zorgani, Abdulaziz A; Ben Slama, Karim; Chouchani, Chedly; Rolain, Jean-Marc

    2015-06-01

    The aim of the present study was to investigate the molecular mechanism of carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates recovered from Libyan hospitals between April 2013 and April 2014. In total, 49 strains (24 P. aeruginosa and 25 A. baumannii) were isolated, including 21 P. aeruginosa and 22 A. baumannii isolates (87.75%) resistant to imipenem (minimum inhibitory concentrations ≥16 μg/ml). The blaVIM-2 gene was detected in 19 P. aeruginosa isolates. All imipenem-resistant P. aeruginosa isolates showed the presence of OprD mutations. Acquired OXA-carbapenemase-encoding genes were present in all A. baumannii isolates: blaOXA-23 (n=19) and blaOXA-24 (n=3). Finally, a total of 13 and 17 different sequence types were assigned to the 21 P. aeruginosa and the 22 A. baumannii carbapenem-resistant isolates, respectively. This study is the first report describing imipenem-resistant P. aeruginosa and A. baumannii isolated from patients in Libya. We report the first case of co-occurrence of blaVIM-2 with oprD porin loss in identical isolates of P. aeruginosa in Libya and demonstrate that these oprD mutations can be used as a tool to study the clonality in P. aeruginosa isolates. We also report the first identification of multidrug-resistant A. baumannii isolates harboring blaOXA-23-like, blaOXA-24-like, and blaOXA-48-like genes in Libya.

  4. Molecular Epidemiology and Characterization of Genotypes of Acinetobacter baumannii Isolates from Regions of South China.

    Science.gov (United States)

    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.

  5. Activity of Gallium Meso- and Protoporphyrin IX against Biofilms of Multidrug-Resistant Acinetobacter baumannii Isolates

    Directory of Open Access Journals (Sweden)

    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.

  6. 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.

  7. Antimicrobial susceptibility profiling and genomic diversity of Acinetobacter baumannii isolates: A study in western Iran.

    Directory of Open Access Journals (Sweden)

    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

  8. 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.

  9. Molecular Characterization of Reduced Susceptibility to Biocides in Clinical Isolates of Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Fei Lin

    2017-09-01

    Full Text Available Active efflux is regarded as a common mechanism for antibiotic and biocide resistance. However, the role of many drug efflux pumps in biocide resistance in Acinetobacter baumannii remains unknown. Using biocide-resistant A. baumannii clinical isolates, we investigated the incidence of 11 known/putative antimicrobial resistance efflux pump genes (adeB, adeG, adeJ, adeT1, adeT2, amvA, abeD, abeM, qacE, qacEΔ1, and aceI and triclosan target gene fabI through PCR and DNA sequencing. Reverse transcriptase quantitative PCR was conducted to assess the correlation between the efflux pump gene expression and the reduced susceptibility to triclosan or chlorhexidine. The A. baumannii isolates displayed high levels of reduced susceptibility to triclosan, chlorhexidine, benzalkonium, hydrogen peroxide, and ethanol. Most tested isolates were resistant to multiple antibiotics. Efflux resistance genes were widely distributed and generally expressed in A. baumannii. Although no clear relation was established between efflux pump gene expression and antibiotic resistance or reduced biocide susceptibility, triclosan non-susceptible isolates displayed relatively increased expression of adeB and adeJ whereas chlorhexidine non-susceptible isolates had increased abeM and fabI gene expression. Increased expression of adeJ and abeM was also demonstrated in multiple antibiotic resistant isolates. Exposure of isolates to subinhibitory concentrations of triclosan or chlorhexidine induced gene expression of adeB, adeG, adeJ and fabI, and adeB, respectively. A point mutation in FabI, Gly95Ser, was observed in only one triclosan-resistant isolate. Multiple sequence types with the major clone complex, CC92, were identified in high level triclosan-resistant isolates. Overall, this study showed the high prevalence of antibiotic and biocide resistance as well as the complexity of intertwined resistance mechanisms in clinical isolates of A. baumannii, which highlights the

  10. Analysis of Genes Encoding Penicillin-Binding Proteins in Clinical Isolates of Acinetobacter baumannii ▿ †

    Science.gov (United States)

    Cayô, Rodrigo; Rodríguez, María-Cruz; Espinal, Paula; Fernández-Cuenca, Felipe; Ocampo-Sosa, Alain A.; Pascual, Álvaro; Ayala, Juan A.; Vila, Jordi; Martínez-Martínez, Luis

    2011-01-01

    There is limited information on the role of penicillin-binding proteins (PBPs) in the resistance of Acinetobacter baumannii to β-lactams. This study presents an analysis of the allelic variations of PBP genes in A. baumannii isolates. Twenty-six A. baumannii clinical isolates (susceptible or resistant to carbapenems) from three teaching hospitals in Spain were included. The antimicrobial susceptibility profile, clonal pattern, and genomic species identification were also evaluated. Based on the six complete genomes of A. baumannii, the PBP genes were identified, and primers were designed for each gene. The nucleotide sequences of the genes identified that encode PBPs and the corresponding amino acid sequences were compared with those of ATCC 17978. Seven PBP genes and one monofunctional transglycosylase (MGT) gene were identified in the six genomes, encoding (i) four high-molecular-mass proteins (two of class A, PBP1a [ponA] and PBP1b [mrcB], and two of class B, PBP2 [pbpA or mrdA] and PBP3 [ftsI]), (ii) three low-molecular-mass proteins (two of type 5, PBP5/6 [dacC] and PBP6b [dacD], and one of type 7 (PBP7/8 [pbpG]), and (iii) a monofunctional enzyme (MtgA [mtgA]). Hot spot mutation regions were observed, although most of the allelic changes found translated into silent mutations. The amino acid consensus sequences corresponding to the PBP genes in the genomes and the clinical isolates were highly conserved. The changes found in amino acid sequences were associated with concrete clonal patterns but were not directly related to susceptibility or resistance to β-lactams. An insertion sequence disrupting the gene encoding PBP6b was identified in an endemic carbapenem-resistant clone in one of the participant hospitals. PMID:21947403

  11. Acinetobacter baumannii Isolated from Lebanese Patients: Phenotypes and Genotypes of Resistance, Clonality, and Determinants of Pathogenicity

    Science.gov (United States)

    Dahdouh, Elias; Hajjar, Micheline; Suarez, Monica; Daoud, Ziad

    2016-01-01

    Introduction: Acinetobacter baumannii is a nosocomial pathogen that usually affects critically ill patients. High mortality rates have been associated with MDR A. baumannii infections. Carbapenem resistance among these isolates is increasing worldwide and is associated with certain International Clones (ICs) and oxacillinases (OXAs). Moreover, this organism possesses a wide range of virulence factors, whose expression is not yet fully understood. In this study, clinical A. baumannii isolates are characterized in terms of antibiotic resistance, mechanisms of carbapenem resistance, clonality, and virulence. Materials and Methods: A. baumannii clinical isolates (n = 90) where obtained from a tertiary care center in Beirut, Lebanon. API 20NE strips in addition to the amplification of blaOXA−51−like were used for identification. Antibiotic susceptibility testing by disk diffusion was then performed in addition to PCRs for the detection of the most commonly disseminated carbapenemases. Clonality was determined by tri-locus PCR typing and doubling times were determined for isolates with varying susceptibility profiles. Biofilm formation, hemolysis, siderophore production, proteolytic activity, and surface motility was then determined for all the isolates. Statistical analysis was then performed for the determination of associations. Results and Discussion: 81 (90%) of the isolates were resistant to carbapenems. These high rates are similar to other multi-center studies in the country suggesting the need of intervention on a national level. 74 (91.3%) of the carbapenem resistant isolates harbored blaOXA−23−like including two that also harbored blaOXA−24−like. 88.9% of the A. baumannii isolates pertained to ICII and three other international clones were detected, showing the wide dissemination of clones into geographically distinct locations. Virulence profiles were highly diverse and no specific pattern was observed. Nevertheless, an association between

  12. Detection of class 1 integron in Acinetobacter baumannii isolates collected from nine hospitals in Turkey

    Institute of Scientific and Technical Information of China (English)

    Ayşegül Çopur ÇİÇek; Yasemin Ay Alıtntop; Ahmet Çalışkan; Yelda Yazıcı; Cemal Sandallı; Azer Özad Düzgün; Ayşegül Saral; Tuba Kayman; Zeynep Çİzmecİ; Pervin Özlem Balcı; Tuba Dal; Mehmet Fırat; İsmail Tosun

    2013-01-01

    Objective: To investigate the antibiotic resistance genes inserted into class 1 and class 2 integrons in Acinetobacter baumannii (A. baumannii) isolates obtained from nine different cities in Turkey. Methods: A collection of 281 A. baumannii clinical isolates were collected from nine diferent state hospitals in Turkey and were confirmed as A. baumannii by conventional biochemical, API testing and bla-OXA-51 specific PCR. The isolates were examined by PCR for existence of class 1 and 2 integron gene cassettes. Results: They were characterized by antimicrobial susceptibility testing and the highest resistance rates were determined for piperacillin (90.03%), ciprofloxacin (87.54%), cefepime and trimethoprim/sulfamethoxazole (81.13%). The lowest resistance rates was for cefotaxime (3.55%). class I integrons were detected in 6.4%(18/281) of A. baumannii strains and no class 2 integron was detected. The gene cassettes of class 1 integrons AacC1-AAC(3)I-aadA1, AacC1-aadA1, AAC(3)-I, AAC(3)-I-AAC(3)-I-aadA1, TEM-1, AAC(3)-I-aadA1-AAC(3)-I-AAC(3)-I, AAC(3)-I-AAC(3)-I-AAC(3)-I-aadA1, AAC(3)-I-aadA1, AAC(3)-I-AAC(3)-I, AAC(3)-I-aadA1- AAC(3)-I-aadA1, AAC(3)-I- AAC(3)-I-aadA1-AAC(3)-I-aadA1 were detected in eighteen strains. The aac genes family were most frequently found integrated into the class 1 integrons and it was followed by aadA genes and TEM-1 genes. Conclusions: This is an extensive study on the distribution of class 1 integron among A. baumannii in Turkey. In addition to these, two new alleles were observed. Their percentage rates of similarity to other cassettes are 95%aadA1 ( TKA18) and 89%aadA1 (ANKA3).

  13. Evaluate the frequency distribution of nonadhesive virulence factors in carbapenemase-producing Acinetobacter baumannii isolated from clinical samples in Kermanshah.

    Science.gov (United States)

    Mohajeri, Parviz; Sharbati, Saba; Farahani, Abbas; Rezaei, Zhaleh

    2016-01-01

    Acinetobacter baumannii which is a Gram-negative bacterium can cause several different infections. The appearance of carbapenemase-producing A. baumannii in recent years has made the treatment process more difficult. The identification of virulence factors (VFs), such as nonadhesives in A. baumannii, helps to fight against related infections. A total of 104 samples from teaching hospitals in Kermanshah, Iran, were collected during a 24 months period (2011-2013). Sample identification was first carried out by biochemical tests, and then their susceptibility to carbapenems was determined using the Kirby-Bauer method. For confirmation of carbapenemase-producing A. baumannii, polymerase chain reaction (PCR) was done for carbapenemase-encoding genes. In addition, the frequency of nonadhesive VFs in carbapenemase-producing isolates was determined by PCR. There were 50 isolates that were identified as carbapenemase-producing A. baumannii. The PCR results showed; 40 isolates (80%) for traT, 17 isolates (34%) for cvaC, and 8 isolates (16%) for iutA, and these encode serum resistance, colicin V and aerobactin, respectively. No significant correlation was observed between these three genes. The mechanism of A. baumannii virulence has always been in question. The role of VFs has also been recognized in other Gram-negative bacteria. According to the prevalence of traT, cvaC and iutA, as nonadhesive VFs, we can suggest that they could be the main mechanism of carbapenemase-producing A. baumannii pathogenesis.

  14. 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.

  15. 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.

  16. Antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii from Tehran, Iran

    Institute of Scientific and Technical Information of China (English)

    Reza Mirnejad; Sepideh Mostofi; Faramaz Masjedian

    2013-01-01

    Objective: To investigate antibiotic resistance and carriage class 1 and 2 integrons in clinical isolates of Acinetobacter baumannii (A. baumannii) from Tehran, Iran. Methods: Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Results:Among isolated A. baumannii strains, 82%were multidrug resistant, 27 samples (54%) were resistant to three or more than three antibiotics and 16 samples (32%) showed resistance to two antibiotics. Integrons were detected from 44 of 50 isolates (88%), with classes 1 and 2 being observed in 42% (21/50) and 82%(41/50) of isolates, respectively. Integron-positive A. baumannii isolates showed higher antibiotic resistance than integron-negative isolates and all showed a multidrug-resistant phenotype. Conclusions:Our findings show that classes 1 and 2 integrons, and especially classes 2 integrons are widely disseminated among A. baumannii strains isolated from Tehran and these structures are playing a major role in the acquisition of multidrug resistance in these strains. So monitoring of drug resistance with investigating carriage class 1 and 2 integrons is very important to plan specific infection control measures due to multidrug resistance A. baumannii in Iran hospitals.

  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. Molecular epidemiology and mechanisms of tigecycline resistance in clinical isolates of Acinetobacter baumannii from a Chinese university hospital.

    Science.gov (United States)

    Deng, Mei; Zhu, Man-Hua; Li, Jun-Jie; Bi, Sheng; Sheng, Zi-Ke; Hu, Fei-Shu; Zhang, Jia-Jie; Chen, Wei; Xue, Xiao-Wei; Sheng, Ji-Fang; Li, Lan-Juan

    2014-01-01

    Because of its remarkable ability to acquire antibiotic resistance and to survive in nosocomial environments, Acinetobacter baumannii has become a significant nosocomial infectious agent worldwide. Tigecycline is one of the few therapeutic options for treating infections caused by A. baumannii isolates. However, tigecycline resistance has increasingly been reported. Our aim was to assess the prevalence and characteristics of efflux-based tigecycline resistance in clinical isolates of A. baumannii collected from a hospital in China. A total of 74 A. baumannii isolates, including 64 tigecycline-nonsusceptible A. baumannii (TNAB) and 10 tigecycline-susceptible A. baumannii (TSAB) isolates, were analyzed. The majority of them were determined to be positive for adeABC, adeRS, adeIJK, and abeM, while the adeE gene was found in only one TSAB isolate. Compared with the levels in TSAB isolates, the mean expression levels of adeB, adeJ, adeG, and abeM in TNAB isolates were observed to increase 29-, 3-, 0.7-, and 1-fold, respectively. The efflux pump inhibitors (EPIs) phenyl-arginine-β-naphthylamide (PAβN) and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could partially reverse the resistance pattern of tigecycline. Moreover, the tetX1 gene was detected in 12 (18.8%) TNAB isolates. To our knowledge, this is the first report of the tetX1 gene being detected in A. baumannii isolates. ST208 and ST191, which both clustered into clonal complex 92 (CC92), were the predominant sequence types (STs). This study showed that the active efflux pump AdeABC appeared to play important roles in the tigecycline resistance of A. baumannii. The dissemination of TNAB isolates in our hospital is attributable mainly to the spread of CC92.

  19. 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.

  20. 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...

  1. 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

    2015-01-01

    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...

  2. Antimicrobial Resistance Mechanisms and Genetic Diversity of Multidrug-Resistant Acinetobacter baumannii Isolated from a Teaching Hospital in Malaysia.

    Science.gov (United States)

    Biglari, Shirin; Hanafiah, Alfizah; Mohd Puzi, Shaliawani; Ramli, Ramliza; Rahman, Mostafizur; Lopes, Bruno Silvester

    2017-07-01

    Multidrug-resistant (MDR) Acinetobacter baumannii has increasingly emerged as an important nosocomial pathogen. The aim of this study was to determine the resistance profiles and genetic diversity in A. baumannii clinical isolates in a tertiary medical center in Malaysia. The minimum inhibitory concentrations of carbapenems (imipenem and meropenem), cephalosporins (ceftazidime and cefepime), and ciprofloxacin were determined by E-test. PCR and sequencing were carried out for the detection of antibiotic resistance genes and mutations. Clonal relatedness among A. baumannii isolates was determined by REP-PCR. Sequence-based typing of OXA-51 and multilocus sequence typing were performed. One hundred twenty-five of 162 (77.2%) A. baumannii isolates had MDR phenotype. From the 162 A. baumannii isolates, 20 strain types were identified and majority of A. baumannii isolates (66%, n = 107) were classified as strain type 1 and were positive for ISAba1-blaOXA-23 and ISAba1-blaADC and had mutations in both gyrA and parC genes at positions, 83 and 80, resulting in serine-to-leucine conversion. REP-PCR analysis showed 129 REP types that generated 31 clones with a 90% similarity cutoff value. OXA-66 variant of the blaOXA-51-like genes was predominantly detected among our A. baumannii clinical isolates belonging to ST195 (found in six clones: 1, 8, 9, 19, 27, and 30) and ST208 (found in clone 21). The study helps us in understanding the genetic diversity of A. baumannii isolates in our setting and confirms that international clone II is the most widely distributed clone in Universiti Kebangsaan Malaysia Medical Centre, Malaysia.

  3. Higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals in Beijing.

    Directory of Open Access Journals (Sweden)

    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.

  4. Surveillance of multidrug resistance-associated genes in Acinetobacter baumannii isolates from elderly patients

    Directory of Open Access Journals (Sweden)

    Zhe DONG

    2012-03-01

    Full Text Available Objective To understand the status of multidrug resistance-associated genes carried by Acinetobacter baumannii isolates from elderly patients in our hospital in order to provide a basis for surveillance of drug-resistance and inflection control. Methods One hundred and twenty A. baumannii isolates were collected from elderly patients between 2008 and 2010. The mean age of the patients was 85 (65 to 95 years. Whonet 5.6 software was used to analyze the resistance rate of 16 antimicrobial agents. Polymerase chain reaction (PCR and the sequencing method were adopted to detect 10 kinds of resistance genes (blaOXA-51-like, blaOXA- 23-like, blaOXA-24-like, blaOXA-58-like, blaTEM, blaampC, armA, ISAba1, intI 1, and intI 2. The corresponding resistance gene profiling(RGP was analyzed and designated according to the status of resistance genes. Results The resistance rates to the remaining 15 kinds of antibiotics varied between 70.8% and 97.5%, with the exception of the sensitivity rate to polymyxin B by up to more than 90%. The positivity rates of blaOXA-51-like, blaOXA-23-like, blaOXA-58-like, blaTEM, blaampC, armA, ISAba1 and intI 1 were 100%, 81.7%, 0.8%, 10.8%, 91.7%, 81.7%, 86.7%, and 83.3% respectively. A total of 18 kinds of drug-resistant gene maps were found, but blaOXA-24-like and intI 2 were not detected. Among these gene maps, the rate of RGP1 (blaOXA-23-like+blaampC+armA+ISAba1+ intI 1 was as high as 60.8%. Conclusions A. baumannii isolates from elderly patients have a higher carrying rate of drug-resistant genes, resulting in severe multidrugresistant conditions. Therefore, full-time infection control personnel and clinical physicians should actively participate in the surveillance, prevention, and control of infections caused by A. baumannii in the elderly.

  5. Antibiotic resistance and OXA-type carbapenemases-encoding genes in airborne Acinetobacter baumannii isolated from burn wards.

    Science.gov (United States)

    Gao, Jing; Zhao, Xiaonan; Bao, Ying; Ma, Ruihua; Zhou, Yufa; Li, Xinxian; Chai, Tongjie; Cai, Yumei

    2014-03-01

    The study was conducted to investigate drug resistance, OXA-type carbapenemases-encoding genes and genetic diversity in airborne Acinetobacter baumannii (A. baumannii) in burn wards. Airborne A. baumannii were collected in burn wards and their corridors using Andersen 6-stage air sampler from January to June 2011. The isolates susceptibility to 13 commonly used antibiotics was examined according to the CLSI guidelines; OXA-type carbapenemases-encoding genes and molecular diversity of isolates were analyzed, respectively. A total of 16 non-repetitive A. baumannii were isolated, with 10 strains having a resistance rate of greater than 50% against the 13 antibiotics. The resistance rate against ceftriaxone, cyclophosvnamide, ciprofloxacin, and imipenem was 93.75% (15/16), but no isolate observed to be resistant to cefoperazone/sulbactam. Resistance gene analyses showed that all 16 isolates carried OXA-51, and 15 isolates carried OXA-23 except No.15; but OXA-24 and OXA-58 resistance genes not detected. The isolates were classified into 13 genotypes (A-M) according to repetitive extragenic palindromic sequence PCR (REP-PCR) results and only six isolates had a homology ≥90%. In conclusion, airborne A. baumannii in the burn wards had multidrug resistance and complex molecular diversity, and OXA-23 and OXA-51 were dominant mechanisms for resisting carbapenems.

  6. Persistence of Multidrug-Resistant Acinetobacter baumannii Isolates Harboring blaOXA-23 and bap for 5 Years.

    Science.gov (United States)

    Sung, Ji Youn; Koo, Sun Hoe; Kim, Semi; Kwon, Gye Cheol

    2016-08-28

    The emergence and dissemination of carbapenemase-producing Acinetobacter baumannii isolates have been reported worldwide, and A. baumannii isolates harboring blaOXA-23 are often resistant to various antimicrobial agents. Antimicrobial resistance can be particularly strong for biofilm-forming A. baumannii isolates. We investigated the genetic basis for carbapenem resistance and biofilm-forming ability of multidrug-resistant (MDR) clinical isolates. Ninety-two MDR A. baumannii isolates were collected from one university hospital located in the Chungcheong area of Korea over a 5-year period. Multiplex PCR and DNA sequencing were performed to characterize carbapenemase and bap genes. Clonal characteristics were analyzed using REP-PCR. In addition, imaging and quantification of biofilms were performed using a crystal violet assay. All 92 MDR A. baumannii isolates involved in our study contained the blaOXA-23 and bap genes. The average absorbance of biomass in Bap-producing strains was much greater than that in non-Bap-producing strains. In our study, only three REP-PCR types were found, and the isolates showing type A or type B were found more than 60 times among unique patients during the 5 years of surveillance. These results suggest that the isolates have persisted and colonized for 5 years, and biofilm formation ability has been responsible for their persistence and colonization.

  7. [Antibiotic resistance of Acinetobacter baumannii strains isolated from clinical specimens in the "Marius Nasta" Pneumology Institute, Bucharest].

    Science.gov (United States)

    Moisoiu, Adriana; Ionită, Monica; Sârbu, Lăcrămioara; Stoica, Corina; Grigoriu, Liliana

    2014-01-01

    Acinetobacter baumannii (A. baumannii) is one of the leading causes of morbidity and mortality in patients who are in critical condition in hospitals and especially in intensive care units (ICU). Long time considered a bacterium with low virulence, A. baumannii has more recently become a cause for major concern in clinical practice due to its high level of antimicrobial resistance. The extend of infections with Acinetobacter baumannii in ICU is caused by multiple factors, such as mechanical ventilation, invasive procedures, the use of a large number of broad spectrum antibiotics and transmission through the hands of medical staff In this study we evaluated the resistance to antibiotics of 213 non-duplicated strains of A. baumannii isolated in the bacteriology laboratory of the "Marius Nasta" lnstitute of Pneumophtisiology (IPMN) from January 2012 to December 2013. These strains originated from patients in medical wards (56), ICU (143) and surgery (14). Strains identification was performed by classical methods on multitest media and with API kits (Bio Merieux). The antibiotic sensitivity was performed on Mueller-Hinton media in accordance with CLSI2013. Analysis of the resistance to antibiotics was the following: carbenicilin (87.3%), ceftriaxone (87.3%), cefoperazone with sulbactam (84.9%), ceftazidime (79.3%), carbapenems (imipenem and/or meropenem--75.1%), fluoroquinolones (ciprofloxacin and/orlevofloxacin--73.7%), cefepime (66.6%), piperacilin with tazobactam (62.4%), amikacin (50.2%), netilmicin (45%), gentamicin (42.7%) and tobramycin (35.6%). In our study, we only found two strains of Acinetobacter baumannii with resistance to colistin and 70 (32.8%) strains sensitive only to colistin, but resistant to all other antibiotics tested. A. baumannii is a pathogen with rapid spread and extended resistance to even newer antimicrobial agents. Due to its ability to survive in the hospital environment, A. baumannii has the immense potential to cause nosocomial

  8. Detection of OXA-Type Carbapenemase Genes in Acinetobacter baumannii Isolates from Nosocomial Infections in Isfahan Hospitals, Iran

    Directory of Open Access Journals (Sweden)

    Vajihe Karbasizade

    2016-02-01

    Full Text Available "> 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 nosocomial infections in Isfahan hospitals.Methods: A total number of 456 clinical specimens were collected from nosocomial infections andevaluated in order to isolate A. baumannii strains. After identification of the isolates, the antibioticsensitivity to carbapenems was assessed using disk diffusion method. The resistance genes of blaOXA-23, 24, 51, and 58 were detected by multiplex PCR method.Results: Fifty A. baumannii isolates were isolated from clinical specimens. Fifty two percent ofthe isolates showed phenotypic resistance to the carbapenems (imipenem and meropenem.According to PCR results, 88% of resistant isolates had ≥1 blaOXA gene. The frequency of resistantisolates bearing blaOXA-23, blaOXA-24 and blaOXA-58 were 77%, 38% and 15% respectively.Conclusions: This study showed the high frequency of carbapenem resistance genes among A.baumannii isolates. Therefore, adopting an appropriate strategy to confine the spreading of thesestrains and also implementing new treatment regimens are necessary.

  9. [Antimicrobial susceptibility and molecular characterization of multidrug-resistant Acinetobacter baumannii isolated in an university hospital].

    Science.gov (United States)

    Direkel, Şahin; Çopur Çiçek, Ayşegül; Karagöz, Alper; Aydoğan Ejder, Nebahat; Oktay, Efdal; Delialioğlu, Nuran; Özgümüş, Osman Birol; Durmaz, Rıza

    2016-10-01

    Acinetobacter baumannii, an aerobic, non-motile, gram-negative bacterium is an important nosocomial pathogen which shows resistance to the most antibiotics. Carbapenems are the most commonly used antibiotics for the treatment of infections caused by this pathogen. However the emergence of resistance against carbapenems in an increasing rate generates serious problems for antimicrobial therapy. The aims of this study were to detect the antibiotic susceptibility, and the presence of blaOXA resistance genes of clinical A.baumannii isolates and to determine the clonal relationship between these isolates. A total of 79 A.baumannii strains isolated from various clinical specimens (37 respiratory tract samples, 11 wound, 10 blood, 8 catheters, 6 tissue, 5 urine, 2 abscess) of the patients admitted to Mersin University Medical School Hospital between May 2012-January 2013, were included in the study. The isolates were identified by conventional methods and Vitek®2 Compact automated system. Antibiotic susceptibilities of the isolates were determined by Kirby-Bauer disk diffusion method and evaluated according to CLSI criteria. The presence of blaOXA-51, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58 genes were detected by an in-house polymerase chain reaction (PCR), and the clonal relationship between the isolates were identified by pulsed-field gel electroforesis (PFGE) using the ApaI restriction enzyme. In our study, all of the isolates were susceptible to colistin, while the resistance rates against piperacillin-tazobactam, ciprofloxacin, imipenem, meropenem, cefoperazone/sulbactam, trimethoprim-sulfamethoxazole, ceftazidime, levofloxacin, gentamicin, tetracycline, ampicillin-sulbactam, amikacin, netilmicin and tigecycline were 97.5%, 96.2%, 94.9%, 94.9%, 93.6%, 91.1%, 88.6%, 86%, 83.6%, 77.2%, 69.6%, 55.7%, 27.8% and 3.8%, respectively. All the isolates were identified as A.baumannii with the OXA-specific PCR and OXA16S rDNA sequence analysis. All of the isolates (100

  10. The resistance and transmission mechanism of Acinetobacter baumannii isolates in a tertiary care hospital, China.

    Science.gov (United States)

    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.

  11. Methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii on computer interface surfaces of hospital wards and association with clinical isolates.

    Science.gov (United States)

    Lu, Po-Liang; Siu, L K; Chen, Tun-Chieh; Ma, Ling; Chiang, Wen-Gin; Chen, Yen-Hsu; Lin, Sheng-Fung; Chen, Tyen-Po

    2009-10-01

    Computer keyboards and mice are potential reservoirs of nosocomial pathogens, but routine disinfection for non-water-proof computer devices is a problem. With better hand hygiene compliance of health-care workers (HCWs), the impact of these potential sources of contamination on clinical infection needs to be clarified. This study was conducted in a 1600-bed medical center of southern Taiwan with 47 wards and 282 computers. With education and monitoring program of hand hygiene for HCWs, the average compliance rate was 74% before our surveillance. We investigated the association of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Acinetobacter baumannii, three leading hospital-acquired pathogens, from ward computer keyboards, mice and from clinical isolates in non-outbreak period by pulsed field gel electrophoresis and antibiogram. Our results revealed a 17.4% (49/282) contamination rate of these computer devices by S. aureus, Acinetobacter spp. or Pseudomonas spp. The contamination rates of MRSA and A. baumannii in the ward computers were 1.1% and 4.3%, respectively. No P. aeruginosa was isolated. All isolates from computers and clinical specimens at the same ward showed different pulsotypes. However, A. baumannii isolates on two ward computers had the same pulsotype. With good hand hygiene compliance, we found relatively low contamination rates of MRSA, P. aeruginosa and A. baumannii on ward computer interface, and without further contribution to nosocomial infection. Our results suggested no necessity of routine culture surveillance in non-outbreak situation.

  12. Clonal relatedness and biofilm formation of OXA-23-producing carbapenem resistant Acinetobacter baumannii isolates from hospital environment.

    Science.gov (United States)

    Aliramezani, Amir; Douraghi, Masoumeh; Hajihasani, Azade; Mohammadzadeh, Mona; Rahbar, Mohammad

    2016-10-01

    Carbapenem-resistant Acinetobacter baumannii (CRAB) is a serious threat for hospitalized patients and it can survive for long periods in hospital settings, particularly on inanimate surfaces. The environment occupied by these resistant and resilient isolates may act as a reservoir for cross-colonization and outbreaks. Here, we aimed to determine the distribution of CRAB in the hospital environment and to characterize their clonal relatedness, susceptibility profile, carriage of blaOXA genes, and biofilm formation. A total of 1080 samples were collected from various environmental surfaces and equipment of two referral hospitals in Tehran, Iran. The A. baumannii isolates were subjected to gyrB multiplex PCR, antibiotic susceptibility testing, biofilm formation assay, pulsed field gel electrophoresis (PFGE), and multiplex PCR for blaOXA-58, blaOXA-24, and blaOXA-23 genes. Eighteen Acinetobacter spp. were isolated; 8 were identified as A. baumannii and 10 as A. lwoffii. Five of A. baumannii isolates were CRAB and exhibited the multidrug-resistant (MDR) phenotype as well. All CRAB isolates produced biofilm, albeit with different levels. Four of CRAB isolates harbored the blaOXA-23. The CRAB isolates were clustered into 3 distinct pulsotypes (PTs). The CRAB isolates belonging to PT1 were detected in two geographically distinct hospitals whereas those belonging to PT3 were found in two different units of same hospital. This study revealed the presence of clonally related OXA-23-producing CRAB in high risk units of referral hospitals as inter- or intra-hospital dissemination. The distribution of multiresistant A. baumannii on several surfaces and areas may increase the risk of transmission of resistant isolates to vulnerable patients.

  13. 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.

  14. 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.

  15. Tn7::In2-8 dispersion in multidrug resistant isolates of Acinetobacter baumannii from Chile Dispersión de Tn7::In2-8 en aislamientos multirresistentes de Acinetobacter baumannii de Chile

    Directory of Open Access Journals (Sweden)

    M. S. Ramírez

    2010-06-01

    Full Text Available Acinetobacter baumannii is considered an important pathogen in our hospital environment having a well-known capacity to acquire different mechanisms of antibiotic resistance. Previous studies in our laboratory had exposed the high dispersion of class 2 integrons in this species. In the present study, we analyzed 7 multiresistant intI2 positive A. baumannii isolates, 6 of which were found to harbour the Tn7::In2-8 element. Our results demonstrate the unusually high distribution of Tn7::In2-8 among different A. baumannii clones from Chile, suggesting a particular behavior of these elements at geographical level.Acinetobacter baumannii, patógeno de importancia clínica en el ámbito hospitalario, es reconocido como un microorganismo que posee la capacidad de evolucionar rápidamente hacia la multirresistencia. Estudios previos efectuados en nuestro laboratorio han demostrado la alta dispersión de los integrones de clase 2 en aislamientos de esta especie. En el presente trabajo se analizaron 7 aislamientos de Acinetobacter baumannii multirresistentes portadores de la integrasa de clase 2, 6 de los cuales portaban el inusual arreglo Tn7::In2-8. Nuestros resultados muestran una elevada frecuencia de dispersión del elemento Tn7::In2-8 en diferentes clones circulantes en Chile, lo que sugiere un comportamiento geográfico particular.

  16. [Homology and carbapenemase gene in Acinetobacter baumannii].

    Science.gov (United States)

    Yan, Qun; Deng, Shuang; Li, Hongling; Zou, Mingxiang

    2012-11-01

    To study the antibiotic resistance evolution, homology, phenotypes and genotypes of carbapenemase in Acinetobacter baumannii from clinical isolates. A total of 72 strains of Acinetobacter baumannii were isolated from Xiangya Hospital of Central South University from March to May 2012. Antimicrobial susceptibility test was carried out by automatic microorganism clinical analytical system VITEK-II. The homology of the 72 strains was analyzed by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). Modified Hodge test was used to screen carbapenemases of the strains. Carbapenemase genes blaOXA-23, blaOXA-40 and blaOXA-58 were also amplified and sequenced. The 72 strains of Acinetobacter baumannii remained sensitive to cefoperazone/sulbactam (resistance rate 8.33%), followed by Amikacin. Otherwise, they were resistant to most of the antimicrobial agents (resistance rate more than 70%). The 72 strains were identified as 7 epidemic clones, A-G, by means of ERIC-PCR and the phylogenetic relationship among D, E, F and G was very close, suggesting a nosocomial infection possibility. Totally 56 strains produced carbapenemase; 61 strains were positive for carbapenemase gene blaOXA-23 and 1 strain positive for blaOXA-58. All strains were negative for carbapenemase gene blaOXA-40. Acinetobacter baumannii strains isolated clinically are resistant to most of the antimicrobial agents and nosocomial infection had been observed. Most of the strains produce carbapenemase, among which, blaOXA-23 gene is the main carbapenemase gene. blaOXA-58 gene exists in the Acinetobacter baumannii isolates from Hunan Province.

  17. Draft genome sequence of a multidrug-resistant Acinetobacter baumannii ST15 (CC15) isolated from Brazil

    Science.gov (United States)

    Chagas, Thiago Pavoni Gomes; Silveira, Melise Chaves; Albano, Rodolpho Mattos; Carvalho-Assef, Ana Paula D’Alincourt; Asensi, Marise Dutra

    2015-01-01

    Acinetobacter baumannii is an important pathogen frequently associated with nosocomial outbreaks around the world. In Brazil, A. baumannii has become particularly problematic because of its prevalence and the carbapenems resistance. Here, we report the draft genome sequence of a multidrug-resistant A. baumannii (ST15/CC15) isolated in 2009 from the state of Espírito Santo (Southeast Brazil). We observed important resistance determinant genes in an estimated genome size of 4,102,788 bp with 3,862 predicted coding regions. A detailed report of the genomic data analysis might help to understand the specific features of highly successful strains belonged to a relevant complex clonal in different Brazilian geographical regions. PMID:26132428

  18. Epidemiological characterization of Acinetobacter baumannii bloodstream isolates from a Chinese Burn Institute: A three-year study.

    Science.gov (United States)

    Huang, Guangtao; Yin, Supeng; Xiang, Lijuan; Gong, Yali; Sun, Kedai; Luo, Xiaoqiang; Zhang, Cheng; Yang, Zichen; Deng, Liuyang; Jiang, Bei; Jin, Shouguang; Chen, Jing; Peng, Yizhi

    2016-11-01

    Acinetobacter baumannii infection is a serious threat to burn patients. Bacteremia due to A. baumannii is becoming the most common cause of mortality following burn. However, the epidemiology of A. baumannii causing burn-related bloodstream infections has rarely been reported. We retrospectively collected 81 A. baumannii isolates from the bloodstream of burn patients over a three-year period. Antibiotic susceptibility tests, the prevalence of antibiotic-resistant genes and sequence typing (ST) were conducted to characterize these strains. Most of the isolates showed an extensive drug-resistant phenotype. The resistance frequencies to imipenem and meropenem were 94% and 91%, respectively. The blaOXA-23-like gene, AmpC, IS-AmpC, PER and SIM are the five most prevalent resistant genes, and their prevalence rates are 93% (75/81), 86% (70/81), 73% (59/81), 73% (59/81) and 52% (42/81), respectively. The 81 isolates were grouped into 10 known and 18 unknown ST types, with ST368 (38%) being the most prevalent. Except for ST457 and four new types (STn2, STn6, STn11 and STn14), the remaining 23 ST types belonged to one clonal complex 92, which is most common among clinical isolate in China. The above results indicated that ST368 isolates possessing both the blaOXA-23-like gene and ampC gene were the main culprits of the increasing nosocomial A. baumannii infection in this study. More attention should be paid to monitoring the molecular epidemiology of A. baumannii isolates from burn patients to prevent further distribution. Such information may help clinicians with therapeutic decisions and infection control in the Burns Institute.

  19. Assessment of intra-species diversity among strains of Acinetobacter baumannii isolated from sites contaminated with petroleum hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Manab Sarma, P.; Bhattacharya, D.; Krishnan, S. [TERI School of Advanced Studies, Center of Bioresources and Biotechnology, New Delhi (India); Lal, B. [TERI School of Advanced Studies, Microbial Biotechnology Division, New Delhi (India)

    2004-06-01

    Intra-species diversity among Acinetobacter baumannii strains isolated from crude oil-contaminated soils from different geographic regions in India was assessed, including their capability to degrade different fractions of total petroleum hydrocarbons. A total of 96 strains were isolated from five different sites. Of the 96 isolates, 25 strains were identified as Acinetobacter baumannii; all of these strains were biochemically profiled and grouped into eight phenovars on the basis of multivariate analysis of their substrate utilization profiles. All strains were able to degrade the total petroleum hydrocarbon fractions of crude oil. Intraspecies relatedness among the 25 strains was determined using tRNA intergenic spacer length polymorphism. Specific variants among the strains with different degradation capacities for different fractions of crude oil were detected. Environmental influences that cause intra-species diversity, such as functional resilience, within the selected strains of A. baumannii were also noted. It is suggested that such diversities may make it possible to select contaminant-specific strains for efficient biotechnological strategies in environmental remediation. 19 refs., 4 tabs., 3 figs.

  20. A 5-year Surveillance Study on Antimicrobial Resistance of Acinetobacter baumannii Clinical Isolates from a Tertiary Greek Hospital

    Science.gov (United States)

    2016-01-01

    Background Acinetobacter baumannii has emerged as a major cause of nosocomial outbreaks. It is particularly associated with nosocomial pneumonia and bloodstream infections in immunocompromised and debilitated patients with serious underlying pathologies. Over the last two decades, a remarkable rise in the rates of multidrug resistance to most antimicrobial agents that are active against A. baumannii has been noted worldwide. We evaluated the rates of antimicrobial resistance and changes in resistance over a 5-year period (2010–2014) in A. baumannii strains isolated from hospitalized patients in a tertiary Greek hospital. Materials and Methods Identification of A. baumannii was performed by standard biochemical methods and the Vitek 2 automated system, which was also used for susceptibility testing against 18 antibiotics: ampicillin/sulbactam, ticarcillin, ticarcillin/clavulanic acid, piperacillin, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, gentamicin, amikacin, tobramycin, ciprofloxacin, tetracycline, tigecycline, trimethoprim/sulfamethoxazole, and colistin. Interpretation of susceptibility results was based on the Clinical and Laboratory Standards Institute criteria, except for tigecycline, for which the Food and Drug Administration breakpoints were applied. Multidrug resistance was defined as resistance to ≥3 classes of antimicrobial agents. Results Overall 914 clinical isolates of A. baumannii were recovered from the intensive care unit (ICU) (n = 493), and medical (n = 252) and surgical (n = 169) wards. Only 4.9% of these isolates were fully susceptible to the antimicrobials tested, while 92.89% of them were multidrug resistant (MDR), i.e., resistant to ≥3 classes of antibiotics. ICU isolates were the most resistant followed by isolates from surgical and medical wards. The most effective antimicrobial agents were, in descending order: colistin, amikacin, trimethoprim/sulfamethoxazole, tigecycline, and tobramycin

  1. Antibacterial Effects of Origanum vulgare Essence Against Multidrug-Resistant Acinetobacter baumannii Isolated From Selected Hospitals of Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Saghi

    2015-02-01

    Full Text Available Background Infection due to Acinetobacter baumannii has become a significant challenge to modern healthcare systems. The rapid emergence and global dissemination of A. baumannii as a major nosocomial pathogen is remarkable and it demonstrates its successful adaptation to the 21st century hospital environment. Recent studies have discussed about essential oil of Origanum vulgare against a range of bacteria, including various species of Staphylococcus, Pseudomonas, Bacillus and Escherichia coli. Objectives The present study aimed to investigate the inhibitory effects O. vulgare essence against multidrug-resistant (MDR strains of A. baumannii from selected hospitals in Tehran, Iran. Materials and Methods This oil was obtained using the hydrodistillation method and analyzed by gas chromatography mass spectrography (GC/MS. The antimicrobial activity against MDR isolates was achieved using disc diffusion method and macro-broth dilution assay. Results Analysis of the essential oil revealed the presence of pulegone (68.59% piperitone (7.8%, piperitenone (7.8%, 1, 8-cineole (1.3%, and carvacrol (1.6% as the major components. The results showed a significant activity against MDR A. baumannii with inhibition zones and minimal inhibitory concentration values in the ranges of 7-15 mm and 20-35 µL/mL respectively. Conclusions This investigation showed that the essence oil of O. vulgare had a potent antimicrobial activity against MDR A. baumannii. Further research is required to evaluate the practical values of therapeutic applications.

  2. Characterization of integrons and associated gene cassettes in Acinetobacter baumannii strains isolated from intensive care unit in Tehran, Iran

    Institute of Scientific and Technical Information of China (English)

    Hossein Goudarzi; Mehdi Azad; Sima Sadat Seyedjavadi; Hadi Azimi; Alireza Salimi Chirani; Vahid Fallah Omrani; Mehdi Goudarzi

    2016-01-01

    Objective: To determine the antimicrobial susceptibility patterns, the frequency of integrons and associated gene cassettes in Acinetobacter baumannii (A. baumannii) strains isolated from selected hospital intensive care units. Methods: During a ten-month period, 120 A. baumannii isolates were studied. The resistance rates to different classes of antimicrobial agents were determined. PCR was used to detect different types of integrons and associated gene cassettes. Results: The resistance rates to the majority of antibiotics tested were found to be be-tween 39.3% and 99.1%. No isolate was observed to be resistant to colistin and poly-myxin B. The rate of extensive drug-resistance among these clinical isolates was 62.5%. The prevalence of class 1 and 2 integrons was found to be 74.1% and 12.5%, respec-tively. Seven different gene cassettes (ampC, aacA4-catB8, ISAba1-blaOXA-23-GES-14, aadA2-cm1A6-GES-14-qacF, VIM-25-GES-24-qacF, dfrA5-ISAba1-blaOXA-51-blaOXA-40 and aadA2-GES-11-IMP-1) were observed in Class 1 integron-carrying strains. Three gene cassettes (IMP-4, VIM-2-VEB-aacA4 and dfrA2-sat-2-aadA4) were detected in class 2 integron-bearing A. baumannii strains. Conclusions: A high prevalence of integron was described among multidrug resistant A. baumannii in the hospital. The findings highlighted the need for continuous surveillance in order to prevent dissemination of multidrug resistance among A. baumannii strains in Iran.

  3. Characteriz ation of integrons and associated gene cassettes in Acinetobacter baumannii strains isolated from intensive care unit in Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Hossein Goudarzi

    2016-09-01

    Full Text Available Objective: To determine the antimicrobial susceptibility patterns, the frequency of integrons and associated gene cassettes in Acinetobacter baumannii (A. baumannii strains isolated from selected hospital intensive care units. Methods: During a ten-month period, 120 A. baumannii isolates were studied. The resistance rates to different classes of antimicrobial agents were determined. PCR was used to detect different types of integrons and associated gene cassettes. Results: The resistance rates to the majority of antibiotics tested were found to be between 39.3% and 99.1%. No isolate was observed to be resistant to colistin and polymyxin B. The rate of extensive drug-resistance among these clinical isolates was 62.5%. The prevalence of class 1 and 2 integrons was found to be 74.1% and 12.5%, respectively. Seven different gene cassettes (ampC, aacA4-catB8, ISAba1-blaOXA-23-GES-14, aadA2-cm1A6-GES-14-qacF, VIM-25-GES-24-qacF, dfrA5-ISAba1-blaOXA-51-blaOXA-40 and aadA2-GES-11-IMP-1 were observed in Class 1 integron-carrying strains. Three gene cassettes (IMP-4, VIM-2-VEB-aacA4 and dfrA2-sat-2-aadA4 were detected in class 2 integron-bearing A. baumannii strains. Conclusions: A high prevalence of integron was described among multidrug resistant A. baumannii in the hospital. The findings highlighted the need for continuous surveillance in order to prevent dissemination of multidrug resistance among A. baumannii strains in Iran.

  4. Molecular epidemiology of multidrug-resistant Acinetobacter baumannii isolates in a university hospital in Nepal reveals the emergence of a novel epidemic clonal lineage.

    Science.gov (United States)

    Shrestha, Shovita; Tada, Tatsuya; Miyoshi-Akiyama, Tohru; Ohara, Hiroshi; Shimada, Kayo; Satou, Kazuhito; Teruya, Kuniko; Nakano, Kazuma; Shiroma, Akino; Sherchand, Jeevan Bdr; Rijal, Basista Psd; Hirano, Takashi; Kirikae, Teruo; Pokhrel, Bharat Mani

    2015-11-01

    The emergence of multidrug-resistant (MDR) Acinetobacter baumannii has become a serious medical problem worldwide. To clarify the genetic and epidemiological properties of MDR A. baumannii strains isolated from a medical setting in Nepal, 246 Acinetobacter spp. isolates obtained from different patients were screened for MDR A. baumannii by antimicrobial disk susceptibility testing. Whole genomes of the MDR A. baumannii isolates were sequenced by MiSeq™ (Illumina), and the complete genome of one isolate (IOMTU433) was sequenced by PacBio RS II. Phylogenetic trees were constructed from single nucleotide polymorphism concatemers. Multilocus sequence types were deduced and drug resistance genes were identified. Of the 246 Acinetobacter spp. isolates, 122 (49.6%) were MDR A. baumannii, with the majority being resistant to aminoglycosides, carbapenems and fluoroquinolones but not to colistin and tigecycline. These isolates harboured the 16S rRNA methylase gene armA as well as bla(NDM-1), bla(OXA-23) or bla(OXA-58). MDR A. baumannii isolates belonging to clonal complex 1 (CC1) and CC2 as well as a novel clonal complex (CC149) have spread throughout a medical setting in Nepal. The MDR isolates harboured genes encoding carbapenemases (OXA and NDM-1) and a 16S rRNA methylase (ArmA).

  5. Molecular Characterization of Multidrug Resistant Strains of Acinetobacter baumannii Isolated from Intensive Care Units in West of Iran

    Science.gov (United States)

    Mohajeri, Parviz; Farahani, Abbas

    2017-01-01

    Introduction According to the results of various studies using phenotypic methods, the prevalence of Multidrug Resistant (MDR) Acinetobacter baumannii (A. baumannii) isolates has been increasing worldwide. Pulsed-Field Gel Electrophoresis (PFGE) technique is known as the gold standard method to determine clonal characterization of bacterial species, especially A. baumannii. Aim To determine the clonal relatedness and investigate the prevalence of integron classes 1 and 2 and genes encoding OXA-23 and 24 in A.baumanii isolates. Materials and Methods A cross-sectional study was conducted from November 2011 to January 2013. A total of 140 A.baumannii isolates collected from three hospitals of Kermanshah were considered out of which 75 ICU isolates were included in this study. Antibiotics susceptibility test was done by disk diffusion method. Polymerase Chain Reaction (PCR) was performed in order to detect class 1 and 2 integrons and blaOXA-23-like, blaOXA-24-like genes. Isolates identified as MDR from a total of 75 Intensive Care Units (ICU) strains were subjected to genotyping for clonal relatedness. Results A total of 37 isolates among 75 ICU isolates were identified as MDR. The maximum drug resistance was observed against ceftriaxone, mezlocycline, cefotaxime, piperacilin, ciprofloxacin and imipenem. Frequency of Class 1 and Class 2 Integrons, blaOXA-23-like and blaOXA-24-like genes were 33(44%), 27(36%), 60(80%) and 14(18.6%) respectively. Four clusters with high level of similarity were obtained showing homogeneity among MDR isolates. Conclusion Significant correlation between presence of integrons and resistance to different classes of antibiotic was observed in this study. Monitoring of drug resistance using gene integrase PCR and blaOXA gene by cluster analysis is very important to plan specific infection control measures due to MDR A. baumannii.

  6. Antimicrobial susceptibility profiling and genomic diversity of multidrug-resistant Acinetobacter baumannii isolates from a teaching hospital in Malaysia.

    Science.gov (United States)

    Kong, Boon Hong; Hanifah, Yasmin Abu; Yusof, Mohd Yasim Mohd; Thong, Kwai Lin

    2011-01-01

    The resistance phenotypes and genomic diversity of 185 Acinetobacter baumannii isolates obtained from the intensive care unit (ICU) of a local teaching hospital in Kuala Lumpur from 2006 to 2009 were determined using antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Antibiogram analyses showed that the isolates were fully resistant to β-lactam antimicrobials and had high resistance rates to the other antimicrobial agents tested. However, the isolates were susceptible to polymyxin B. Resistance to cefoperazone/sulbactam was only detected in strains isolated from 2007 to 2009. Some environmental isolates and an isolate from the hands of a healthcare worker (HCW) had identical resistance profiles and PFGE profiles that were closely related to patient isolates. Cluster analyses based on the PFGE profiles showed there was a persistent clone of endemic isolates in the ICU environment. The transmission route from HCWs to fomites to patients, which caused a long-term infection in the ICU of the University Malaya Medical Centre, was observed in this study. These data provide a better understanding of A. baumannii epidemiology within the hospital and the possible transmission routes. Knowledge of changes in the resistance rates of A. baumannii in our local hospital will improve antimicrobial therapy.

  7. Synergistic effect of Myrtus communis L. essential oils and conventional antibiotics against multi-drug resistant Acinetobacter baumannii wound isolates.

    Science.gov (United States)

    Aleksic, Verica; Mimica-Dukic, Neda; Simin, Natasa; Nedeljkovic, Natasa Stankovic; Knezevic, Petar

    2014-10-15

    Acinetobacter baumannii is a rapidly emerging, highly resistant clinical pathogen with increasing prevalence. In recent years, the limited number of antimicrobial agents available for treatment of infections with multi-drug resistant (MDR) strains reinforced tendency for discovery of novel antimicrobial agents or treatment strategies. The aim of the study was to determine antimicrobial effectiveness of three Myrtus communis L. essential oils, both alone and in combination with conventional antibiotics, against MDR A. baumannii wound isolates. The results obtained highlighted the occurrence of good antibacterial effect of myrtle oils when administered alone. Using checkerboard method, the combinations of subinhibitory concentrations of myrtle essential oils and conventional antibiotics, i.e. polymixin B and ciprofloxacine were examined. The results proved synergism among M. communis L. essential oils and both antibiotics against MDR A. baumannii wound isolates, with a FIC index under or equal 0.50. Combination of subinhibitory concentrations of essential oils and ciprofloxacin most frequently reduced bacterial growth in synergistic manner. The similar has been shown for combination with polymyxin B; furthermore, the myrtle essential oil resulted in re-sensitization of the MDR wound isolates, i.e. MICs used in combination were below the cut off for the sensitivity to the antibiotic. Time-kill curve method confirmed efficacy of myrtle essential oil and polymyxin B combination, with complete reduction of bacterial count after 6h. The detected synergy offers an opportunity for future development of treatment strategies for potentially lethal wound infections caused by MDR A. baumannii.

  8. OXA-23 and ISAba1-OXA-66 class D β-lactamases in Acinetobacter baumannii isolates from companion animals.

    Science.gov (United States)

    Ewers, Christa; Klotz, Peter; Leidner, Ursula; Stamm, Ivonne; Prenger-Berninghoff, Ellen; Göttig, Stephan; Semmler, Torsten; Scheufen, Sandra

    2017-01-01

    Acinetobacter baumannii is recognised as a major pathogen of nosocomial infections that frequently show resistance to last-resort antimicrobials. To investigate whether A. baumannii from companion animals harbour carbapenem resistance mechanisms, 223 clinical isolates obtained from veterinary clinics between 2000 and 2013 in Germany were screened for carbapenem-non-susceptibility employing meropenem-containing Mueller-Hinton agar plates. Minimum inhibitory concentration (MIC) data were obtained using the VITEK(®)2 system. Assignment to international clones (ICs) was done by multiplex PCR or repetitive sequence-based PCR employing the DiversiLab system. Clonality was studied using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Genes encoding carbapenemases and aminoglycoside-modifying enzymes were detected by PCR. In three samples from dogs, carbapenem-resistant A. baumannii carrying the blaOXA-23 gene on plasmids and located on transposon Tn2008 were identified. The isolates belonged to sequence type ST1(P) (clonal complex CC1/IC1/pulsotype II) and ST10(P) (CC10/IC8/pulsotype IV) according to the Pasteur MLST scheme, and to ST231(Ox) (CC109) and ST585(Ox) (CC447) following the Oxford scheme. Insertion sequence ISAba1 was identified upstream of blaOXA-66 in 58 A. baumannii isolates. MLST referred them to ST2(P) (CC2/IC2/pulsotypes I and III), ST208(Ox), ST350(Ox) and ST556(Ox) (all CC118), respectively. PFGE suggested nosocomial spread of these highly related strains, which frequently demonstrated a multidrug-resistant phenotype, in one veterinary clinic. These data show that A. baumannii from companion animals reveal resistance determinants and clonal lineages of strains globally emerging in humans. This suggests an interspecies transmission and warrants molecular surveillance of A. baumannii in veterinary clinics to mitigate its further spread.

  9. Molecular epidemiology and antimicrobial resistance phenotypes of Acinetobacter baumannii isolated from patients in three hospitals in southern Vietnam.

    Science.gov (United States)

    Tuan Anh, Nguyen; Nga, Tran Vu Thieu; Tuan, Huynh Minh; Tuan, Nguyen Si; Y, Dao Minh; Vinh Chau, Nguyen Van; Baker, Stephen; Duong, Ho Huynh Thuy

    2017-01-01

    Multidrug resistance in the nosocomial pathogen Acinetobacter baumannii limits therapeutic options and impacts on clinical care. Resistance against carbapenems, a group of last-resort antimicrobials for treating multidrug-resistant (MDR) A. baumannii infections, is associated with the expression (and over-expression) of carbapenemases encoded by the blaOXA genes. The aim of this study was to determine the prevalence of antimicrobial-resistant A. baumannii associated with infection in three hospitals in southern Vietnam and to characterize the genetic determinants associated with resistance against carbapenems. We recovered a total of 160 A. baumannii isolates from clinical samples collected in three hospitals in southern Vietnam from 2012 to 2014. Antimicrobial resistance was common; 119/160 (74 %) of isolates were both MDR and extensively drug resistant (XDR). High-level imipenem resistance (>32 µg ml-1) was determined for 109/117 (91.6 %) of the XDR imipenem-nonsusceptible organisms, of which the majority (86.7 %) harboured the blaOXA-51 and blaOXA-23 genes associated with an ISAba1 element. Multiple-locus variable number tandem repeat analysis segregated the 160 A. baumannii into 107 different multiple-locus variable number tandem repeat analysis types, which described five major clusters. The biggest cluster was a clonal complex composed mainly of imipenem-resistant organisms that were isolated from all three of the study hospitals. Our study indicates a very high prevalence of MDR/XDR A. baumannii causing clinically significant infections in hospitals in southern Vietnam. These organisms commonly harboured the blaOXA-23 gene with ISAba1 and were carbapenem resistant; this resistance phenotype may explain their continued selection and ongoing transmission within the Vietnamese healthcare system.

  10. Methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii on computer interface surfaces of hospital wards and association with clinical isolates

    Directory of Open Access Journals (Sweden)

    Ma Ling

    2009-10-01

    Full Text Available Abstract Background Computer keyboards and mice are potential reservoirs of nosocomial pathogens, but routine disinfection for non-water-proof computer devices is a problem. With better hand hygiene compliance of health-care workers (HCWs, the impact of these potential sources of contamination on clinical infection needs to be clarified. Methods This study was conducted in a 1600-bed medical center of southern Taiwan with 47 wards and 282 computers. With education and monitoring program of hand hygiene for HCWs, the average compliance rate was 74% before our surveillance. We investigated the association of methicillin-resistant Staphylococcus aureus (MRSA, Pseudomonas aeruginosa and Acinetobacter baumannii, three leading hospital-acquired pathogens, from ward computer keyboards, mice and from clinical isolates in non-outbreak period by pulsed field gel electrophoresis and antibiogram. Results Our results revealed a 17.4% (49/282 contamination rate of these computer devices by S. aureus, Acinetobacter spp. or Pseudomonas spp. The contamination rates of MRSA and A. baumannii in the ward computers were 1.1% and 4.3%, respectively. No P. aeruginosa was isolated. All isolates from computers and clinical specimens at the same ward showed different pulsotypes. However, A. baumannii isolates on two ward computers had the same pulsotype. Conclusion With good hand hygiene compliance, we found relatively low contamination rates of MRSA, P. aeruginosa and A. baumannii on ward computer interface, and without further contribution to nosocomial infection. Our results suggested no necessity of routine culture surveillance in non-outbreak situation.

  11. Association of biofilm production with multidrug resistance among clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa from intensive care unit

    Directory of Open Access Journals (Sweden)

    Jeetendra Gurung

    2013-01-01

    Full Text Available Background and Aims: Given choice, bacteria prefer a community-based, surface-bound colony to an individual existence. The inclination for bacteria to become surface bound is so ubiquitous in diverse ecosystems that it suggests a strong survival strategy and selective advantage for surface dwellers over their free-ranging counterparts. Virtually any surface, biotic or abiotic (animal, mineral, or vegetable is suitable for bacterial colonization and biofilm formation. Thus, a biofilm is "a functional consortium of microorganisms organized within an extensive exopolymeric matrix." Materials and Methods: The present study was undertaken to detect biofilm production from the repertoire stocks of Acinetobacter baumannii (A. baumannii and Pseudomonas aeruginosa (P. aeruginosa obtained from clinical specimens. The tube method was performed to qualitatively detect biofilm production. Results: A total of 109 isolates of both organisms were included in the study, out of which 42% (46/109 isolates showed biofilm detection. Among the biofilm producers, 57% of P. aeruginosa and 73% of A. baumannii showed multidrug resistance (MDR pattern which was statistically significant in comparison to nonbiofilm producers (P < 0.001. Conclusion: To the best of our knowledge, this is the only study to have tested the biofilm production in both P. aeruginosa and A. baumannii in a single study. Biofilm production and MDR pattern were found to be significantly higher in A. baumannii than P. aeruginosa. Antibiotic resistance was significantly higher among biofilm producing P. aeruginosa than non producers. Similarly, antibiotic resistance was significantly higher among biofilm producing A. baumannii than non producers.

  12. In vitro antimicrobial synergy of colistin with rifampicin and carbapenems against colistin-resistant Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Hong, Duck Jin; Kim, Jung Ok; Lee, Hyukmin; Yoon, Eun-Jeong; Jeong, Seok Hoon; Yong, Dongeun; Lee, Kyungwon

    2016-10-01

    Increased use of colistin in a clinical setting had resulted in the emergence of colistin-resistant (CoR) Acinetobacter baumannii. Combination therapy has been studied as a new approach to treat infections caused by A. baumannii. Here, we investigated the in vitro antimicrobial synergistic activities of several antimicrobial agent combinations against CoR A. baumannii. A total of 41 non-duplicate clinical isolates of CoR A. baumannii from a tertiary care hospital in Korea were prospectively collected from April 2012 to December 2014. As a control group, 41 carbapenem-resistant but colistin-susceptible (CoS) A. baumannii strains were also evaluated. Minimum inhibitory concentrations (MICs) of antimicrobial agents were determined by Etest in triplicate, and in vitro synergy tests were performed by the Etest MIC:MIC ratio method. Synergistic activity was determined as the sum of each antimicrobial agent's fractional inhibitory concentration evaluated (ΣFIC): synergy, ≤0.5; indifference, >0.5-4; and antagonism, >4. Synergistic activities were more frequently observed in the CoR group than the CoS group for combinations of colistin-rifampicin (80.5% vs. 14.6%, Pbaumannii clinical isolates to the susceptible range (≤ 2 μg/mL) more frequently (61.0%, 25/41, both) than combination with imipenem (29.3%, 12/41). Clinical trials are needed to prove the in vivo efficacy of those antimicrobial combinations that exhibited significant in vitro antimicrobial synergistic effects against CoR A. baumannii.

  13. 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.

  14. First occurrence of blaOXA-58 in Acinetobacter baumannii isolated from a clinical sample in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Carolina de Souza Gusatti

    2012-03-01

    Full Text Available This is the first report of an Acinetobacter baumannii from clinical origin carrying the blaOXA-58 gene in Brazil. The isolate included in this study was from a patient during an outbreak in Porto Alegre, RS, Southern Brazil, in 2007. It was resistant to most of the beta-lactams tested, it has also the blaOXA-65 gene and the ISAba1 sequence located upstream to both blaOXA genes detected and it has a MIC of imipenem of 64 μg/mL.

  15. 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.

  16. Characterization of NDM-1- and OXA-23-producing Acinetobacter baumannii isolates from inanimate surfaces in a hospital environment in Algeria.

    Science.gov (United States)

    Zenati, K; Touati, A; Bakour, S; Sahli, F; Rolain, J M

    2016-01-01

    Investigation of several outbreaks of multidrug-resistant Acinetobacter baumannii infection has demonstrated that contamination of the inanimate hospital environment could be implicated in the spread of these multidrug-resistant strains. To investigate the occurrence of carbapenem-resistant A. baumannii on inanimate surfaces and possible dissemination in the hospital environment in Algeria as a potential source of infection in humans. A. baumannii strains were isolated from the hospital environment and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility was determined using disc diffusion and E-test methods. Carbapenemase activity was detected using microbiological tests, including modified Hodge test, modified Carba NP test, and EDTA test. Carbapenem resistance determinants were studied by polymerase chain reaction (PCR) and sequencing. Clonal relatedness was determined using multi-locus sequence typing (MLST). A total of 67 A. baumannii isolates were obtained from 868 environmental samples and identified by MALDI-TOF MS. Among them, 61 isolates were resistant to imipenem with minimum inhibitory concentration >32 μg/mL and positive by the modified Hodge test and modified Carba NP test. In addition, the activity of carbapenemase was inhibited by EDTA in 32 strains. PCR and sequencing showed the presence of blaOXA-23 gene in 29 strains, and the blaNDM-1 gene in 32 isolates. MLST demonstrated the presence of five types of ST (ST19, ST2, ST85, ST98, and ST115). Our study demonstrated the dissemination of carbapenemase-producing A. baumannii strains recovered from inanimate surfaces in a hospital environment, surrounding patients, healthcare workers and visitors, in Algeria as a potential source for nosocomial infection. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  17. Emergence of Colistin- and Carbapenem-Resistant Acinetobacter baumannii ST2 Clinical Isolate in Algeria: First Case Report.

    Science.gov (United States)

    Bakour, Sofiane; Olaitan, Abiola Olumuyiwa; Ammari, Houria; Touati, Abdelaziz; Saoudi, Souad; Saoudi, Kenza; Rolain, Jean-Marc

    2015-06-01

    The aim of this study was to investigate the prevalence and the mechanisms of carbapenem and colistin resistance in Acinetobacter baumannii clinical isolates in an Algerian hospital. Twelve isolates were collected between October 2013 and March 2014. All isolates were resistant to almost all antibiotics tested with a high-level resistance to imipenem (minimum inhibitory concentrations [MICs] >32 mg/L) with one strain showing resistance to colistin (MIC=16 mg/L). The results of the modified Hodge test and the modified Carba NP test were positive for all isolates. Besides, the activity of β-lactamases was inhibited by EDTA in only two isolates. All the 12 isolates contained the naturally occurring blaOXA-51-like gene. Ten of them harbored the OXA β-lactamases: blaOXA-23 (six isolates) and blaOXA-24 (four isolates) genes, while two isolates were positive for blaNDM-1 gene. The colistin-resistant isolate producing OXA-24 enzyme harbored a single mutation in the pmrB gene. Multilocus sequence typing demonstrated that the 12 isolates belonged to 2 clones: 10 to ST2 and 2 to ST85. Here, we describe the mechanisms of carbapenem resistance and we report the first colistin and carbapenemase-producing A. baumannii clinical isolate from a patient in Algeria.

  18. Genome organization of epidemic Acinetobacter baumannii strains

    Directory of Open Access Journals (Sweden)

    Triassi Maria

    2011-10-01

    Full Text Available Abstract Background Acinetobacter baumannii is an opportunistic pathogen responsible for hospital-acquired infections. A. baumannii epidemics described world-wide were caused by few genotypic clusters of strains. The occurrence of epidemics caused by multi-drug resistant strains assigned to novel genotypes have been reported over the last few years. Results In the present study, we compared whole genome sequences of three A. baumannii strains assigned to genotypes ST2, ST25 and ST78, representative of the most frequent genotypes responsible for epidemics in several Mediterranean hospitals, and four complete genome sequences of A. baumannii strains assigned to genotypes ST1, ST2 and ST77. Comparative genome analysis showed extensive synteny and identified 3068 coding regions which are conserved, at the same chromosomal position, in all A. baumannii genomes. Genome alignments also identified 63 DNA regions, ranging in size from 4 o 126 kb, all defined as genomic islands, which were present in some genomes, but were either missing or replaced by non-homologous DNA sequences in others. Some islands are involved in resistance to drugs and metals, others carry genes encoding surface proteins or enzymes involved in specific metabolic pathways, and others correspond to prophage-like elements. Accessory DNA regions encode 12 to 19% of the potential gene products of the analyzed strains. The analysis of a collection of epidemic A. baumannii strains showed that some islands were restricted to specific genotypes. Conclusion The definition of the genome components of A. baumannii provides a scaffold to rapidly evaluate the genomic organization of novel clinical A. baumannii isolates. Changes in island profiling will be useful in genomic epidemiology of A. baumannii population.

  19. Extrahuman Epidemiology of Acinetobacter baumannii in Lebanon

    Science.gov (United States)

    Rafei, Rayane; Hamze, Monzer; Pailhoriès, Hélène; Eveillard, Matthieu; Marsollier, Laurent; Joly-Guillou, Marie-Laure; Dabboussi, Fouad

    2015-01-01

    The presence of Acinetobacter baumannii outside hospitals is still a controversial issue. The objective of our study was to explore the extrahospital epidemiology of A. baumannii in Lebanon. From February 2012 to October 2013, a total of 73 water samples, 51 soil samples, 37 raw cow milk samples, 50 cow meat samples, 7 raw cheese samples, and 379 animal samples were analyzed by cultural methods for the presence of A. baumannii. Species identification was performed by rpoB gene sequencing. Antibiotic susceptibility was investigated, and the A. baumannii population was studied by two genotyping approaches: multilocus sequence typing (MLST) and blaOXA-51 sequence-based typing (SBT). A. baumannii was detected in 6.9% of water samples, 2.7% of milk samples, 8.0% of meat samples, 14.3% of cheese samples, and 7.7% of animal samples. All isolates showed a susceptible phenotype against most of the antibiotics tested and lacked carbapenemase-encoding genes, except one that harbored a blaOXA-143 gene. MLST analysis revealed the presence of 36 sequence types (STs), among which 24 were novel STs reported for the first time in this study. blaOXA-51 SBT showed the presence of 34 variants, among which 21 were novel and all were isolated from animal origins. Finally, 30 isolates had new partial rpoB sequences and were considered putative new Acinetobacter species. In conclusion, animals can be a potential reservoir for A. baumannii and the dissemination of new emerging carbapenemases. The roles of the novel animal clones identified in community-acquired infections should be investigated. PMID:25616788

  20. Novel Aminoglycoside Resistance Transposons and Transposon-Derived Circular Forms Detected in Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates.

    Science.gov (United States)

    Karah, Nabil; Dwibedi, Chinmay Kumar; Sjöström, Karin; Edquist, Petra; Johansson, Anders; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2016-01-11

    Acinetobacter baumannii has emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates of A. baumannii collected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (n = 16) and CC25 (n = 7). Resistance to carbapenems was related to blaOXA-23 (20 isolates), blaOXA-24/40-like (6 isolates), blaOXA-467 (1 isolate), and ISAba1-blaOXA-69 (1 isolate). Ceftazidime resistance was associated with blaPER-7 in the CC25 isolates. Two classical point mutations were responsible for resistance to quinolones in all the isolates. Isolates with high levels of resistance to aminoglycosides carried the 16S rRNA methylase armA gene. The isolates also carried a variety of genes encoding aminoglycoside-modifying enzymes. Several novel structures involved in aminoglycoside resistance were identified, including Tn6279, ΔTn6279, Ab-ST3-aadB, and different assemblies of Tn6020 and TnaphA6. Importantly, a number of circular forms related to the IS26 or ISAba125 composite transposons were detected. The frequent occurrence of these circular forms in the populations of several isolates indicates a potential role of these circular forms in the dissemination of antibiotic resistance genes.

  1. Outbreak Caused by blaOXA-72-Producing Acinetobacter baumannii ST417 Detected in Clinical and Environmental Isolates.

    Science.gov (United States)

    Tamayo-Legorreta, Elsa; Turrubiartes-Martínez, Edgar; Garza-Ramos, Ulises; Niño-Moreno, Perla; Barrios, Humberto; Sánchez-Pérez, Alejandro; Reyna-Flores, Fernando; Tovar-Oviedo, Juana; Magaña-Aquino, Martin; Cevallos, Miguel Angel; Silva-Sanchez, Jesus

    2016-03-01

    We characterized an outbreak of imipenem-resistant Acinetobacter baumannii with clinical and environmental isolates from a tertiary care hospital in San Luis Potosi, Mexico. During a 4-month period, a total of 32 nonrepetitive imipenem-resistant clinical isolates of A. baumannii were collected. All isolates were susceptible to colistin and tigecycline and resistant to cefepime, ceftazidime, ceftriaxone, imipenem, and meropenem. Genotyping by pulsed-field gel electrophoresis showed a major clone (A). Multilocus sequence type (MLST) analysis was performed, revealing sequence type (ST) 417 (ST417) and 208 (ST208). The blaIMP-, blaVIM-, blaGIM-, blaSIM-, blaNDM-type, and blaOXA-type (blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, and blaOXA-58-like) genes were screened and showed that the blaOXA-51-like and blaOXA-24-like genes were present in all isolates. Sequencing and southern hybridization were performed, confirming the presence of the blaOXA-72 gene and its plasmid-borne nature. In addition, the blaOXA-72-XerC/XerD-like association was identified. These findings indicate that a clonal spread of blaOXA-72-producing A. baumannii ST417 had occurred throughout the hospital. The ST417 corresponded with a previous ST described in the United States.

  2. Bioprospecting of marine Streptomycetes sp. for its antagonistic activity on MDR Pseudomonas aeruginosa and Acinetobacter baumannii isolates

    Directory of Open Access Journals (Sweden)

    Shanthi John

    2014-02-01

    Full Text Available Objective: To assess the antimicrobial activity of the Actinobacteria bioactive secondary metabolite and characterize the drug resistance mechanisms of Pseudomonas aeruginosa (P. aeruginosa and Acinetobacter baumannii (A. baumannii. Methods: Potential marine Actinobacteria were isolated and the crude extract was purified using thin layer chromatography, the fractions were tested for antimicrobial activity and phylogeny of the selected strain was analyzed. Isolated pathogenic strains were screened for extended spectrum beta-lactamase, mannan-binding lectin, AmpC production, efflux mechanism and polymerase chain reaction. The cephalosporin and carbapenem antibiotics were synergistically tested along with Streptomyces sp. PM49 fraction by combination disc test and double-disc synergy test. Heterogeneous susceptibility assay, minimum inhibitory concentration and expression of DnaK (Hsp70 were determined. Results: Streptomyces sp. PM49 active fraction of Rfvalue 0.69 showed antimicrobial activity and an inhibitory zone of 15 to 7 mm obtained. About 34.1% of P. aeruginosa and 4.8% of A. baumannii were multiple drug resistant. AmpC β-lactamase was found in 12% of A. baumannii, efflux mechanism was putatively positive in 8/23 of P. aeruginosa and 3/20 of A. baumannii. Combination disc test and double-disc synergy test with both PM49 compound and antibiotics showed an increase in the inhibitory zone of <3 mm to 4 mm, three P. aeruginosa isolates expressed blaIMP. Heteroresistant subcolonies grew at a frequency of 3 ×10-5 to 1 ×10-5. Stress induction analysis showed increase of DnaK during heat shock at 52 °C, the levels of protein doubled after exposure to the antibiotics. Conclusions: Novel unexplored Streptomyces spp. antimicrobial constituents can be developed as an inhibitor and can be substituted along with the available antibiotics to combat the drug resistant pathogens.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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....

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

    Science.gov (United States)

    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. 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.

  10. In vitro activity of tigecycline and comparators against carbapenem-susceptible and resistant Acinetobacter baumannii clinical isolates in Italy

    Directory of Open Access Journals (Sweden)

    Carattoli Alessandra

    2008-02-01

    Full Text Available Abstract Background In a recent multi-centre Italian survey (2003–2004, conducted in 45 laboratories throughout Italy with the aim of monitoring microorganisms responsible for severe infections and their antibiotic resistance, Acinetobacter baumannii was isolated from various wards of 9 hospitals as one of the most frequent pathogens. One hundred and seven clinically significant strains of A. baumannii isolates were included in this study to determine the in vitro activity of tigecycline and comparator agents. Methods Tests for the susceptibility to antibiotics were performed by the broth microdilution method as recommended by CLSI guidelines. The following antibiotics were tested: aztreonam, piperacillin/tazobactam, ampicillin/sulbactam, ceftazidime, cefepime, imipenem, meropenem tetracycline, doxycycline, tigecycline, gentamicin, amikacin, ciprofloxacin, colistin, and trimethoprim/sulphametoxazole. The PCR assay was used to determine the presence of OXA, VIM, or IMP genes in the carbapenem resistant strains. Results A. baumannii showed widespread resistance to ceftazidime, ciprofloxacin and aztreonam in more than 90% of the strains; resistance to imipenem and meropenem was 50 and 59% respectively, amikacin and gentamicin were both active against about 30% of the strains and colistin about 99%, with only one strain resistant. By comparison with tetracyclines, tigecycline and doxycycline showed a higher activity. In particular, tigecycline showed a MIC90 value of 2 mg/L and our strains displayed a unimodal distribution of susceptibility being indistinctly active against carbapenem-susceptible and resistant strains, these latter possessed OXA-type variant enzymes. Conclusion In conclusion, tigecycline had a good activity against the MDR A. baumannii strains while maintaining the same MIC90 of 2 mg/L against the carbapenem-resistant strains.

  11. Complete genome analysis of three Acinetobacter baumannii clinical isolates in China for insight into the diversification of drug resistance elements.

    Directory of Open Access Journals (Sweden)

    Lingxiang Zhu

    Full Text Available BACKGROUND: The emergence and rapid spreading of multidrug-resistant Acinetobacter baumannii strains has become a major health threat worldwide. To better understand the genetic recombination related with the acquisition of drug-resistant elements during bacterial infection, we performed complete genome analysis on three newly isolated multidrug-resistant A. baumannii strains from Beijing using next-generation sequencing technology. METHODOLOGIES/PRINCIPAL FINDINGS: Whole genome comparison revealed that all 3 strains share some common drug resistant elements including carbapenem-resistant bla OXA-23 and tetracycline (tet resistance islands, but the genome structures are diversified among strains. Various genomic islands intersperse on the genome with transposons and insertions, reflecting the recombination flexibility during the acquisition of the resistant elements. The blood-isolated BJAB07104 and ascites-isolated BJAB0868 exhibit high similarity on their genome structure with most of the global clone II strains, suggesting these two strains belong to the dominant outbreak strains prevalent worldwide. A large resistance island (RI of about 121-kb, carrying a cluster of resistance-related genes, was inserted into the ATPase gene on BJAB07104 and BJAB0868 genomes. A 78-kb insertion element carrying tra-locus and bla OXA-23 island, can be either inserted into one of the tniB gene in the 121-kb RI on the chromosome, or transformed to conjugative plasmid in the two BJAB strains. The third strains of this study, BJAB0715, which was isolated from spinal fluid, exhibit much more divergence compared with above two strains. It harbors multiple drug-resistance elements including a truncated AbaR-22-like RI on its genome. One of the unique features of this strain is that it carries both bla OXA-23 and bla OXA-58 genes on its genome. Besides, an Acinetobacter lwoffii adeABC efflux element was found inserted into the ATPase position in BJAB0715. CONCLUSIONS

  12. Complete genome sequence of Acinetobacter baumannii XH386 (ST208, a multi-drug resistant bacteria isolated from pediatric hospital in China

    Directory of Open Access Journals (Sweden)

    Youhong Fang

    2016-03-01

    Full Text Available Acinetobacter baumannii is an important bacterium that emerged as a significant nosocomial pathogen worldwide. The rise of A. baumannii was due to its multi-drug resistance (MDR, while it was difficult to treat multi-drug resistant A. baumannii with antibiotics, especially in pediatric patients for the therapeutic options with antibiotics were quite limited in pediatric patients. A. baumannii ST208 was identified as predominant sequence type of carbapenem resistant A. baumannii in the United States and China. As we knew, there was no complete genome sequence reproted for A. baumannii ST208, although several whole genome shotgun sequences had been reported. Here, we sequenced the 4087-kilobase (kb chromosome and 112-kb plasmid of A. baumannii XH386 (ST208, which was isolated from a pediatric hospital in China. The genome of A. baumannii XH386 contained 3968 protein-coding genes and 94 RNA-only encoding genes. Genomic analysis and Minimum inhibitory concentration assay showed that A. baumannii XH386 was multi-drug resistant strain, which showed resistance to most of antibiotics, except for tigecycline. The data may be accessed via the GenBank accession number CP010779 and CP010780.

  13. Structural determination of the K14 capsular polysaccharide from an ST25 Acinetobacter baumannii isolate, D46.

    Science.gov (United States)

    Kenyon, Johanna J; Hall, Ruth M; De Castro, Cristina

    2015-11-19

    The structure of the capsular polysaccharide (CPS) recovered from D46, an extensively antibiotic resistant ST25 Acinetobacter baumannii clinical isolate, was elucidated. The structure was resolved on the basis of NMR spectroscopy and chemical analyses, and was found to contain a branched neutral pentasaccharide with a backbone composed of GalpNAc and Galp residues, all d configured, and a d-Glcp side group. The KL14 gene cluster found in the D46 genome includes genes for four glycosyltransferases but no modules for synthesis of complex sugars, and this is consistent with the structure of K14. The K14 structure and KL14 sequence clarify the relationship between the structure and K locus sequence for A. nosocomialis isolate LUH5541. The identity of the first sugar of the K14 repeat unit (K unit), and the functions of the four encoded glycosyltransferases and Wzy polymerase were predicted.

  14. Prevalence PER and VEB beta-lactamase Genes among Acinetobacter baumannii Isolated from Patients in Tehran by PCR

    Directory of Open Access Journals (Sweden)

    Abbas Nazari Monazam

    2014-12-01

    Full Text Available Background and Aim: According to numerous reports of infections caused by spectrum beta lactamases (ESBLs producing Acinetobacter baumannii in our country in recent years, this study was performed to define the antibiotic susceptibility patterns and detect the prevalence PER  and VEB beta-lactamase genes among  A.baumannii isolated from patients in Tehran by PCR. Materials and Methods: 100 A.baumannii clinical isolates collected from various hospitals in Tehran during a year, using special culture media and biochemical tests were identified. The antibiograms of the isolates against 11 antibiotics by disk diffusion method (Disk diffusion according to Clinical and Laboratory Standards Institute (CLSI guidelines was performed. Then minimum inhibitory concentrations (MIC was determined for cefepime and ceftazidime and for the identification of ESBL-producing strains was used in combination disk method, and finally to assess the prevalence of PER and VEB beta-lactamase genes using specific primers PCR was performed. Results: Antibiograms results showed that the greatest resistance to the antibiotics amikacin, cefepime, and less resistance to polymyxin B were obtained. Rates of multi-drug resistant strains of about 70% was achieved. Of the isolates studied, the MIC of ceftazidime in 84% and for cefepime in 91% were ≥ 128 μg/ml. The results of the combined-disk test demonstrated that 20% of samples were ESBL positive. The PCR results showed that 47% and 32% of our isolates had PER and VEB genes respectively. Conclusions: Regarding to existence of PER and VEB genes in this bacterium and possibility of transformation of these genes to the other bacteria, reconsideration in antibiotics consumption patterns and more attention to nosocomial infections control criteria are inevitable.

  15. COST-EFFECTIVE PRODUCTION OF THE BIO-PLASTIC POLY-β-HYDROXYBUTYRATE USING ACINETOBACTER BAUMANNII ISOLATE P39

    Directory of Open Access Journals (Sweden)

    Noha Salah Elsayed

    2016-06-01

    Full Text Available Being biodegradable and biocompatible natural polymer, poly-β-hydroxybutyrate (PHB drew the attention of scientists to substitute synthetic plastics in our daily lives. However, its industrial production is hampered by its high cost. In this study, an extensive screening program was done to isolate bacteria with high PHB productivity from agricultural fields and develop a cost-effective PHB production. A promising bacterial isolate Acinetobacter baumannii P39 was recovered and identified using 16S ribosomal gene sequencing. It produced 24% PHB per dry weight after 48 h. Several experiments were conducted to optimize the composition of the culture medium and environmental factors for the selected isolate. Results revealed that 60% aeration, 28°C incubation temperature and initial pH 7.5 showed the highest productivity. Besides, 0.7% corn oil and 0.1 g/L peptone were the best carbon and nitrogen sources, respectively. Substituting glucose with corn oil led to a 23% reduction in total input cost and an estimate price for 1kg PHB is 20.5 L.E. Strain improvement by UV mutation succeeded in improving PHB production by two fold in the selected mutant P39M2. Finally, this study valorizes usage of Acinetobacter isolate in PHB production in addition to solving the critical problem of high cost of production.

  16. 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...

  17. Incidence of Acinetobacter baumannii and other pathogens isolated from Intensive Care Unit of the Hospital San Carlo, Genoa - Voltri

    Directory of Open Access Journals (Sweden)

    Silvana Delfino

    2010-12-01

    Full Text Available Acinetobacter baumannii is an emerging pathogen of great impact especially in nosocomial settings due to its complex epidemiology that makes its control very difficult. In this study the strains isolated from the Intensive Care Unite were analysed. Materials and methods. All the patients admitted into intensive care of San Carlo Hospital,Voltri, Genoa, Italy (ASL 3 in the period from May to December 2009 were considered.A total of 63 patients were studied including 31 women and 32 men, with an average of 73 years old.The study considered the following biological samples (N: bronchial aspirate and sputum (84, urine (55, blood (28, and other materials (36.The positive samples were processed for strain identification and evaluations of its antibiotic susceptibility pattern by standard VITEK2 system, following the Clinical and Laboratory Standard Institute Guidelines. Results and Conclusions. From samples taken into account, the prevalent percentage of bacterial species collected was registered by Gram negative (46.3%, followed by Gram positive (36.4%, and fungi (17.3%. Considering Gram negative isolates A. baumannii and Escherichia coli resulted among the prevalent pathogens (23.4 and 24.5% respectively. This microorganism was collected especially from bronchial aspirate (13 followed by urines (4, blood cultures (2 and other materials (3. On the basis of the analysis of the antibiotic susceptibility tests, colistin was active on the totality (100% of A. baumannii, followed by tigecycline (96.77%.Amikacin resulted also active against a large proportion of these isolates (93.3%. Present findings confirm the great multidrug resistance phenotype of A. baumanii against the main classes of antimicrobial agents and its dangerous diffusion in the Intensive Care Units. For these reasons a continuous surveillance of the evolution of this pathogen toward antibiotic resistance is requested. In this contest it will be important an evaluation of antibiotic

  18. In vitro activities of nontraditional antimicrobials against multiresistant Acinetobacter baumannii strains isolated in an intensive care unit outbreak.

    Science.gov (United States)

    Appleman, M D; Belzberg, H; Citron, D M; Heseltine, P N; Yellin, A E; Murray, J; Berne, T V

    2000-04-01

    Fifteen multiresistant Acinetobacter baumannii isolates from patients in intensive care units and 14 nonoutbreak strains were tested to determine in vitro activities of nontraditional antimicrobials, including cefepime, meropenem, netilmicin, azithromycin, doxycycline, rifampin, sulbactam, and trovafloxacin. The latter five drugs were further tested against four of the strains for bactericidal or bacteriostatic activity by performing kill-curve studies at 0.5, 1, 2, and 4 times their MICs. In addition, novel combinations of drugs with sulbactam were examined for synergistic interactions by using a checkerboard configuration. MICs at which 90% of the isolates tested were inhibited for antimicrobials showing activity against the multiresistant A. baumannii strains were as follows (in parentheses): doxycycline (1 microg/ml), azithromycin (4 microg/ml), netilmicin (1 microg/ml), rifampin (8 microg/ml), polymyxin (0.8 U/ml), meropenem (4 microg/ml), trovafloxacin (4 microg/ml), and sulbactam (8 microg/ml). In the kill-curve studies, azithromycin and rifampin were rapidly bactericidal while sulbactam was more slowly bactericidal. Trovafloxacin and doxycycline were bacteriostatic. None of the antimicrobials tested were bactericidal against all strains tested. The synergy studies demonstrated that the combinations of sulbactam with azithromycin, rifampin, doxycycline, or trovafloxacin were generally additive or indifferent.

  19. High Prevalence of Iron Acquisition Genes Among Acinetobacter baumannii Strains Isolated From Patients With Urinary Tract Infections in Southeast of Iran

    Directory of Open Access Journals (Sweden)

    Ali Abdi

    2015-11-01

    Full Text Available Background Acinetobacter baumannii is the most clinically prominent species of the Acinetobacter genus and is commonly found in hospital environments. In mammals, the iron element is virtually unavailable to invading bacteria, being mainly incorporated into iron transport and storage proteins. Therefore, iron acquisition systems are important factors for the pathogenicity of A. baumannii strains. Objectives The aim of this study was to determine the frequency of iron acquisition genes among A. baumannii isolates, collected from patients with urinary tract infections, for the first time in Iran. Patients and Methods A total of 100 A. baumannii isolates were collected from patients with urinary tract infections in Zabol, southeast of Iran. All isolates were evaluated to determine the prevalence of iron acquisition genes, including tonB (TonB-dependent receptor, barA (acinetobactin ABC transporter, feoB (ferrous iron transport protein B, entA (acinetobactin siderophore precursor, A1S_2563 (siderophore-interacting protein, and hemO (heme oxygenase using the multiplex polymerase chain reaction (PCR method. Results A high prevalence of genes encoding iron acquisition systems were observed in A. baumannii isolates. The frequency of tonB, barA, feoB, entA, A1S_2563, and hemO genes were 85, 97, 99, 98, 99, and 95%, respectively. Based on the distribution of the various iron acquisition genes, all the studied isolates exhibited seven gene profile patterns. Conclusions This is the first report on the prevalence of iron acquisition genes among A. baumannii isolates collected from patients with urinary tract infections. The high prevalence of iron acquisition genes in A. baumannii isolates suggests that these virulence factors play an important role in the development of urinary tract infections.

  20. Microbicides Alter the Expression and Function of RND-Type Efflux Pump AdeABC in Biofilm-Associated Cells of Acinetobacter baumannii Clinical Isolates.

    Science.gov (United States)

    Krishnamoorthy, Suvarna; Shah, Bhavikkumar P; Lee, Hiu Ham; Martinez, Luis R

    2015-10-12

    Acinetobacter baumannii is a Gram-negative bacterium that causes nosocomial infections worldwide. This microbe's propensity to form biofilms allows it to persist and to survive on clinical abiotic surfaces for long periods. In fact, A. baumannii biofilm formation and its multidrug-resistant nature severely compromise our capacity to care for patients in hospital environments. In contrast, microbicides such as cetrimide (CT) and chlorhexidine (CHX) play important roles in the prevention and treatment of infections. We assessed the efficacy of CT and CHX, either alone or in combination, in eradicating A. baumannii biofilms formed by clinical isolates, by using stainless steel washers to mimic hard abiotic surfaces found in hospital settings. We demonstrated that increasing amounts of each microbicide, alone or in combination, were able to damage and to reduce the viability of A. baumannii biofilms efficaciously. Interestingly, the adeB gene of the resistance-nodulation-cell division (RND) family is predominantly associated with acquired resistance to antimicrobials in A. baumannii. We showed that CT and CHX adversely modified the expression and function of the RND-type efflux pump AdeABC in biofilm-associated A. baumannii cells. Furthermore, we established that these microbicides decreased the negative charges on A. baumannii cell membranes, causing dysregulation of the efflux pump and leading to cell death. Our findings suggest that CT and CHX, alone or in combination, can be used efficaciously for eradication of A. baumannii from hospital surfaces, in order to reduce infections caused by this nosocomial agent.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. Survey of Antibiotic Resistance and Frequency of blaOXA-23 and blaOXA-24 Oxacillinase in Acinetobacter baumannii Isolated from Tracheal Tube Specimens of Patients Hospitalized in Intensive Care Units in Isfahan city

    OpenAIRE

    M Ghalebi; Eslami, G.; H Zandi; Farhang, A; Vakili, M.; N. Mohammadi; A Dehghan Banadkouki

    2017-01-01

    Introduction: Acinetobacter baumannii is a non-fermentative gram-negative coccobacill that is prevalent in intensive care units. Carbapenem resistant A.baumannii isolates have been reported worldwide. Oxasillinase beta-lactamase enzymes are involved in bacterial resistance to carbapenem. This study aimed to determine the prevalence of blaOXA-23 and blaOXA-24 genes in A. baumannii isolated from tube discharge specimens of hospitalized patients in the intensive care units of the hospitals in Is...

  6. 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

  7. An Investigation of Antibacterial Resistance Patterns Among Acinetobacter baumannii and Pseudomonas aeruginosa Isolates Collected from Intensive Care Units of a University-Affiliated Hospital in Ahvaz, Iran

    Science.gov (United States)

    Izadpour, Farrokh; Ranjbari, Nastaran; Aramesh, Mohammad-Reza; Moosavian, Mojtaba; ShahAli, Shiva; Larki, Farzaneh; Tabesh, Hamed; Morvaridi, Afrooz

    2016-01-01

    Background In recent decades, multidrug-resistant non-fermenting Gram-negative pathogens, particularly Acinetobacter baumannii and Pseudomonas aeruginosa, have been recognized as a major cause of healthcare-associated and nosocomial infections and outbreaks. Objectives The aim of this study was to determine the prevalence and pattern of antibiotic resistance in A. baumannii and P. aeruginosa isolates collected from intensive care units (ICUs). Methods One hundred fifty-five clinical isolates, including 80 (51.6%) isolates of A. baumannii and 75 (48.4%) isolates of P. aeruginosa, from hospitalized patients in the ICUs of a teaching hospital in Ahvaz, Iran, were collected from January 1 to December 30, 2013. The organisms were identified with conventional bacteriological methods, and antimicrobial susceptibility testing was performed on all isolates in accordance with clinical laboratory and standards institute (CLSI) guidelines. Results The maximum resistance rates among A. baumannii isolates were observed for ciprofloxacin and trimethoprim-sulfamethoxazole (96.9% and 95.2%, respectively). For P. aeruginosa isolates, the maximum resistance rates were reported for ceftriaxone and trimethoprim-sulfamethoxazole (97.2% and 92.4%, respectively). Conclusions The majority of A. baumannii and P. aeruginosa isolates were found to be resistant to commonly recommended antibiotics. Therefore, surveillance of antibiotic consumption and proper antibiotic administration guidelines are essential for preventing major outbreaks in the future. PMID:27800136

  8. Iron limitation enhances acyl homoserine lactone (AHL) production and biofilm formation in clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Modarresi, Farzan; Azizi, Omid; Shakibaie, Mohammad Reza; Motamedifar, Mohammad; Mosadegh, Ellahe; Mansouri, Shahla

    2015-01-01

    Acinetobacter baumannii is an important source of infections in intensive care units (ICUs) of our hospitals in Kerman, Iran and the most frequently isolated strains produce biofilm. There is a little information about role of iron (Fe) levels on acyl homoserine lactone (AHL) production and biofilm formation in this microorganism. In the present study, we investigated the influence of iron-III limitation on AHL, siderophore, catechol and virulence factors in the biofilm forming clinical strains of A. baumannii. A total of 65 non-duplicated multidrug resistance (MDR) strains of A. baumannii were isolated from patients in ICUs of 2 hospitals in Kerman, Iran. Antibiotic susceptibility, siderophore and other iron chelators, hemolysis, cell twitching motility, capsule, gelatinase and DNase were studied. Presence of quorum sensing, LuxI and LuxR genes was detected by multiplex-PCR. AHL activity quantified by colorimetric method and the functional groups were determined by Fourier Transform Infra-Red Spectroscopy (FT-IR). Biofilm formation was detected by microtiter plate technique. All of the isolates were resistant to third generation of cephalosporins, ciprofloxacin, levofloxacin, tetracycline, whereas, 78% and 81% were resistant to amikacin and carbapenems, respectively. The siderophore activity was highest at 20 μM Fe(3+) (70%); however, it decreased to 45% as concentration of Fe(3+) increased to 80 μM. Furthermore, screening of the isolates for LuxI and LuxR genes showed that presence of both genes required in the isolates with high AHL activity. FT-IR analysis indicated C=O bond of the lactone ring and primary amides. Significantly, a higher amount of AHL (70%) was detected in the presence of low concentration of iron-III (20 μM); as iron concentration increased to 80 μM, the AHL activity was reduced to 40% (P ≤ 0.05). All the isolates exhibited twitching motility and had a capsule. No any gelatinase or DNase activity was detected. Quantification of the

  9. Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical Isolate Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Kok-Gan Chan

    2014-01-01

    Full Text Available Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs. These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL and N-octanoyl-homoserine lactone (C8-HSL, was detected.

  10. 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.

  11. Antibiotic Resistance and the Frequency of Extended-Spectrum B-Lactamase in Acinetobacter baumannii Isolated from Clinical Samples through Phenotypic Methods

    Directory of Open Access Journals (Sweden)

    Somayeh Vafaei

    2013-07-01

    Full Text Available AbstractBackground and objectives: Nowadays Acinetobacter baumannii is as one of the problematic opportunistic pathogens, especially in intensive care because of the incidence of drug-resistant strains in the world. The purpose of current study was to define the antibiotic susceptibility patterns and detect the prevalence of producing strains of extended-spectrum β-lactamase (ESBL in A. baumannii isolates which had been isolated from clinical samples with combined disk test.Materials and methods: This study was conducted in 3 major hospitals in Tehran on 500 clinical samples during 6 months. After identification of isolates in species level using cultural and biochemical methods, in order to determine sensitivity of 100 isolates of A. baumannii to 11 antibiotics, the susceptibility tests were carried out according to CLSI guidelines using disk diffusion method. Also MIC (Minimum inhibitory concentrations was determined for cefepime and ceftazidime, and finally to identify of producing strains of ESBL was applied phenotypic method of combined disk. Results: In this survey, 100 A. baumannii strains, 30 A. lwoffii strains and other Acinetobacter species were isolated from patients. The majority of isolates were from blood specimens. Isolates of A.baumannii revealed the highest resistance to cefepime, ceftriaxone, amikacin, imipenem, piperacillin - tazobactam, meropenem, gentamicin, tobramycina and tetracycline, respectively. Ampicillin - sulbactam and polymyxin B considered as effective drugs in this study. Multi-drug resistance in these strains was 70%. The Total isolates studied the Minimum inhibitory concentrations of ceftazidime in 84% samples was MIC ≥ 128 μg/ml and Minimum inhibitory concentrations of cefepime in 91% samples was MIC≥ 128 μg/ml. According to the results of combined disk test, 20% of total samples were demonstrated to be ESBL positive.Conclusion: Regarding to produce of ESBL in this bacterium and possibility of

  12. Detection of AdeABC efflux pump genes in tetracycline-resistant Acinetobacter baumannii isolates from burn and ventilator-associated pneumonia patients

    Directory of Open Access Journals (Sweden)

    Maryam Beheshti

    2014-01-01

    Full Text Available Purpose: Acinetobacter baumannii is the most prevalent nosocomial pathogen which have been emerged in the past three decades worldwide. The aim of this study was to assess the distribution of the AdeABC efflux pump genes, associated with tetracycline resistance in Acinetobacter baumannii isolates collected from burn infection and Ventilator Associated Pneumonia (VAP. Materials and Methods: Ninety-eight A. baumannii isolates were collected from two different hospitals in Tehran, Iran. Tetracycline susceptibility testing was performed by disk diffusion and agar dilution methods according to the CLSI guidelines. The presence of adeSR, adeB, drug efflux system genes in resistant isolates was assessed by polymerase chain reaction (PCR. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP was used as a chemical inhibitor agent to assess the contribution of AdeABC efflux pump in tetracycline resistance isolates. Results: Approximately 48% (47 out of 98 of isolates showed resistance to tetracycline which 14 (14.2% isolates were corresponded to burn infection and the remaining 33 (33.8% strains were isolated from VAP. All tetracycline resistant isolates have AdeABC in PCR assay. The reduction of tetracycline MICs by using 50 μg/ml CCCP were as follows: in 18 isolates 2-4 fold reduction in MICs, 26 isolates showed 8 fold reduction,1 isolate showed 16 fold, 1 isolate showed 32 fold and the remaining 1 isolate showed 128 fold reduction in MICs. Conclusion: The results showed significant correlation between tetracycline resistance and AdeABC efflux pump genes in resistant A. baumannii isolates.

  13. Genomic comparison of multi-drug resistant invasive and colonizing Acinetobacter baumannii isolated from diverse human body sites reveals genomic plasticity

    Directory of Open Access Journals (Sweden)

    Hsiao William W

    2011-06-01

    Full Text Available Abstract Background Acinetobacter baumannii has recently emerged as a significant global pathogen, with a surprisingly rapid acquisition of antibiotic resistance and spread within hospitals and health care institutions. This study examines the genomic content of three A. baumannii strains isolated from distinct body sites. Isolates from blood, peri-anal, and wound sources were examined in an attempt to identify genetic features that could be correlated to each isolation source. Results Pulsed-field gel electrophoresis, multi-locus sequence typing and antibiotic resistance profiles demonstrated genotypic and phenotypic variation. Each isolate was sequenced to high-quality draft status, which allowed for comparative genomic analyses with existing A. baumannii genomes. A high resolution, whole genome alignment method detailed the phylogenetic relationships of sequenced A. baumannii and found no correlation between phylogeny and body site of isolation. This method identified genomic regions unique to both those isolates found on the surface of the skin or in wounds, termed colonization isolates, and those identified from body fluids, termed invasive isolates; these regions may play a role in the pathogenesis and spread of this important pathogen. A PCR-based screen of 74 A. baumanii isolates demonstrated that these unique genes are not exclusive to either phenotype or isolation source; however, a conserved genomic region exclusive to all sequenced A. baumannii was identified and verified. Conclusions The results of the comparative genome analysis and PCR assay show that A. baumannii is a diverse and genomically variable pathogen that appears to have the potential to cause a range of human disease regardless of the isolation source.

  14. Epidemiology and resistance features of Acinetobacter baumannii isolates from the ward environment and patients in the burn ICU of a Chinese hospital.

    Science.gov (United States)

    Gong, Yali; Shen, Xiaodong; Huang, Guangtao; Zhang, Cheng; Luo, Xiaoqiang; Yin, Supeng; Wang, Jing; Hu, Fuquan; Peng, Yizhi; Li, Ming

    2016-08-01

    Acinetobacter baumannii is an important opportunistic pathogen that causes severe nosocomial infections, especially in intensive care units (ICUs). Over the past decades, an everincreasing number of hospital outbreaks caused by A. baumannii have been reported worldwide. However, little attention has been directed toward the relationship between A. baumannii isolates from the ward environment and patients in the burn ICU. In this study, 88 A. baumannii isolates (26 from the ward environment and 62 from patients) were collected from the burn ICU of the Southwest Hospital in Chongqing, China, from July through December 2013. Antimicrobial susceptibility testing results showed that drug resistance was more severe in isolates from patients than from the ward environment, with all of the patient isolates being fully resistant to 10 out of 19 antimicrobials tested. Isolations from both the ward environment and patients possessed the β-lactamase genes bla OXA-51, bla OXA-23, bla AmpC, bla VIM, and bla PER. Using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), these isolates could be clustered into 4 major PFGE types and 4 main sequence types (ST368, ST369, ST195, and ST191) among which, ST368 was the dominant genotype. Epidemiologic and molecular typing data also revealed that a small-scale outbreak of A. baumannii infection was underway in the burn ICU of our hospital during the sampling period. These results suggest that dissemination of β-lactamase genes in the burn ICU might be closely associated with the high-level resistance of A. baumannii, and the ICU environment places these patients at a high risk for nosocomial infection. Cross-contamination should be an important concern in clinical activities to reduce hospitalacquired infections caused by A. baumannii.

  15. 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.

  16. Acinetobacter baumannii and multiple antibiotic resistances

    Directory of Open Access Journals (Sweden)

    Yeni Arroyave

    2012-06-01

    Full Text Available Acinetobacter baumannii is a strict aerobic gran negative coccobacillus, able to acquire multiple resistance to broad-spectrum antibiotics due to its ability to take fragments of genetic material from other bacteria, for further incorporation of this material into its own chromosome. Acinetobacter baumannii is the cause of several nosocomial infections and of numerous outbreaks in hospitals over different continents. This paper includes a literature review of scientific articles published since January 2010 about this microorganism, its environment, mechanisms of resistance and virulence, as well as commonly used treatment.

  17. Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

    Directory of Open Access Journals (Sweden)

    Ebrahim Babapour

    2016-06-01

    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.

  18. Preliminary evaluation of adherence on abiotic and cellular surfaces of Acinetobacter baumannii strains isolated from catheter tips

    Directory of Open Access Journals (Sweden)

    Gislaine Franco de Moura Costa

    Full Text Available The cell surface hydrophobicity and adhesion to abiotic and cellular surfaces was tested in five clinical strains of Acinetobacter baumannii isolated from catheter tips. Biochemical and molecular characteristics of these strains were also studied. Hydrophobicity was characterized by a test for affinity to xylene. Adhesion to abiotic surfaces (polystyrene, formica, latex and glass was evaluated in Petri plates using the stamp technique. Buccal epithelial cells were used for tests of adhesion to cellular surfaces. Adhesion to the catheter was evaluated by repeatedly rinsing the catheters and rolling them over nutrient agar. Molecular typing of the strains was done by the ERIC-PCR technique. The degree of hydrophobicity of the strains varied from hydrophobic to hydrophilic. All the strains adhered to the cell surfaces and to the catheters, and three of them strongly adhered to latex, polystyrene and formica. Catheter adhesion was reduced by meropenem. We found a direct relationship between the degree of bacterial hydrophobicity and adhesion to the abiotic surfaces, but not with adhesion to cellular surfaces, which suggests that different mechanisms are involved in adherence.

  19. Preliminary evaluation of adherence on abiotic and cellular surfaces of Acinetobacter baumannii strains isolated from catheter tips

    Directory of Open Access Journals (Sweden)

    Gislaine Franco de Moura Costa

    2006-10-01

    Full Text Available The cell surface hydrophobicity and adhesion to abiotic and cellular surfaces was tested in five clinical strains of Acinetobacter baumannii isolated from catheter tips. Biochemical and molecular characteristics of these strains were also studied. Hydrophobicity was characterized by a test for affinity to xylene. Adhesion to abiotic surfaces (polystyrene, formica, latex and glass was evaluated in Petri plates using the stamp technique. Buccal epithelial cells were used for tests of adhesion to cellular surfaces. Adhesion to the catheter was evaluated by repeatedly rinsing the catheters and rolling them over nutrient agar. Molecular typing of the strains was done by the ERIC-PCR technique. The degree of hydrophobicity of the strains varied from hydrophobic to hydrophilic. All the strains adhered to the cell surfaces and to the catheters, and three of them strongly adhered to latex, polystyrene and formica. Catheter adhesion was reduced by meropenem. We found a direct relationship between the degree of bacterial hydrophobicity and adhesion to the abiotic surfaces, but not with adhesion to cellular surfaces, which suggests that different mechanisms are involved in adherence.

  20. Characterization, sequencing and comparative genomic analysis of vB_AbaM-IME-AB2, a novel lytic bacteriophage that infects multidrug-resistant Acinetobacter baumannii clinical isolates.

    Science.gov (United States)

    Peng, Fan; Mi, Zhiqiang; Huang, Yong; Yuan, Xin; Niu, Wenkai; Wang, Yahui; Hua, Yuhui; Fan, Huahao; Bai, Changqing; Tong, Yigang

    2014-07-05

    With the use of broad-spectrum antibiotics, immunosuppressive drugs, and glucocorticoids, multidrug-resistant Acinetobacter baumannii (MDR-AB) has become a major nosocomial pathogen species. The recent renaissance of bacteriophage therapy may provide new treatment strategies for combatting drug-resistant bacterial infections. In this study, we isolated a lytic bacteriophage vB_AbaM-IME-AB2 has a short latent period and a small burst size, which clear its host's suspension quickly, was selected for characterization and a complete genomic comparative study. The isolated bacteriophage vB_AbaM-IME-AB2 has an icosahedral head and displays morphology resembling Myoviridae family. Gel separation assays showed that the phage particle contains at least nine protein bands with molecular weights ranging 15-100 kDa. vB_AbaM-IME-AB2 could adsorb its host cells in 9 min with an adsorption rate more than 99% and showed a short latent period (20 min) and a small burst size (62 pfu/cell). It could form clear plaques in the double-layer assay and clear its host's suspension in just 4 hours. Whole genome of vB_AbaM-IME-AB2 was sequenced and annotated and the results showed that its genome is a double-stranded DNA molecule consisting of 43,665 nucleotides. The genome has a G + C content of 37.5% and 82 putative coding sequences (CDSs). We compared the characteristics and complete genome sequence of all known Acinetobacter baumannii bacteriophages. There are only three that have been sequenced Acinetobacter baumannii phages AB1, AP22, and phiAC-1, which have a relatively high similarity and own a coverage of 65%, 50%, 8% respectively when compared with our phage vB_AbaM-IME-AB2. A nucleotide alignment of the four Acinetobacter baumannii phages showed that some CDSs are similar, with no significant rearrangements observed. Yet some sections of these strains of phage are nonhomologous. vB_AbaM-IME-AB2 was a novel and unique A. baumannii bacteriophage. These findings suggest a common

  1. Transcriptomic analysis of colistin-susceptible and colistin-resistant isolates identifies genes associated with colistin resistance in Acinetobacter baumannii.

    Science.gov (United States)

    Park, Y K; Lee, J-Y; Ko, K S

    2015-08-01

    The emergence of colistin-resistant Acinetobacter baumannii is concerning, as colistin is often regarded as the last option for treating multidrug-resistant (MDR) A. baumannii infections. Using mRNA sequencing, we compared whole transcriptomes of colistin-susceptible and colistin-resistant A. baumannii strains, with the aim of identifying genes involved in colistin resistance. A clinical colistin-susceptible strain (06AC-179) and a colistin-resistant strain (07AC-052) were analysed in this study. In addition, a colistin-resistant mutant (06AC-179-R1) derived from 06AC-179 was also included in this study. High throughput mRNA sequencing was performed with an Illumina HiSeq TM 2000. In total, six genes were identified as associated with colistin resistance in A. baumannii. These six genes encode PmrAB two-component regulatory enzymes, PmrC (a lipid A phosphoethanolamine transferase), a glycosyltransferase, a poly-β-1,6-N-acetylglucosamine deacetylase, and a putative membrane protein. Matrix-assisted laser desorption/ionization time of flight mass spectrometry revealed that all three colistin-resistant strains used in this study had modified lipid A structure by addition of phosphoethanolamine. As genes found in our results are all associated with either lipopolysaccharide biosynthesis or electrostatic changes in the bacterial cell membrane, lipopolysaccharide modification might be one of the principal modes of acquisition of colistin resistance in some A. baumannii strains.

  2. Evaluation of the antibacterial effect of Echium amoenum Fisch. et Mey. against multidrug resistant Acinetobacter baumannii strains isolated from burn wound infection

    Directory of Open Access Journals (Sweden)

    Mandana Sabour

    2015-02-01

    Full Text Available Introduction and aims: Acinetobacter baumannii in recent decay has become an increasing concern in hospitals for its ability to acquire antibiotic resistance determinants rapidly and becoming resistant to almost all of the antibiotic classes. Borage (Echium amoenum  Fisch. et Mey, is a wild annual plant of Boraginaceae family, grows in northern mountains of Iran and has largely been used by Iranian folk as a mood enhancer, anti anxiolytic, anti inflammatory, a laxative, an emollients and also it has been used  for treatment of infectious diseases. So, in this study the methanolic extract of dried flowers of Echium amoenom were tested against the isolates of Acinetobacter baumannii from wound of burn patients.Materials and methods: 30 drug resistant Acinetobacter baumannii strains which were isolated from burn wounds at the Motahari hospital of Tehran were selected. Antibacterial activity of the methanolic extract was evaluated by the disc diffusion method based on CLSI protocol 2012Results: The mean diameter of the inhibition zone for different extracts  were; 9.967±6.139 mm at the concentration of 4000 ppm, at the concentration of 400 ppm 13.37±5.45 mm, 13.53±5.49 mm at the concentration of 200 ppm, 14.77±5.17mm  at the concentration of 100 ppm and 14.13±5.7806mm  at the concentration of 50 ppm.Conclusion: clinical strains of the A. baumannii were almost highly resistant to imipenem which is the common choice of antibiotic therapy in the hospitals. Due to the calculated p value ≤ 0.05 in this study, it can say that borage extract can be as good as or even better than the imipenem which is used in the hospitals now.

  3. Nosocomial infection by sequence type 357 multidrug-resistant Acinetobacter baumannii isolates in a neonatal intensive care unit in Daejeon, Korea.

    Science.gov (United States)

    Sung, Ji Youn; Koo, Sun Hoe; Cho, Hye Hyun; Kwon, Kye Chul

    2013-07-01

    Acinetobacter baumannii is an important microorganism responsible for a number of nosocomial outbreaks, in particular, in intensive care units (ICUs). We investigated a nosocomial infection caused by multidrug-resistant (MDR) A. baumannii in a neonatal intensive care unit (NICU) in Korea. A. baumannii isolates were characterized using Etest (AB Biodisk, Sweden), two multiplex PCR assays, and multilocus sequence typing (MLST) scheme. PCR and PCR mapping experiments were performed for detecting and characterizing the determinants of antimicrobial resistance. Eight strains isolated from an NICU belonged to European (EU) clone II and revealed only one sequence type (ST), namely, ST357. All the isolates were susceptible to imipenem but were resistant to amikacin, gentamicin, ceftazidime, cefepime, and ciprofloxacin. To the best of our knowledge, this is the first report of a nosocomial infection in an NICU in Korea caused by ST357 MDR/carbapenem-susceptible A. baumannii strains. This result demonstrates that nosocomial outbreaks of MDR/carbapenem-susceptible strains as well as MDR/carbapenem-resistant isolates may occur in NICUs.

  4. Spread of the blaOXA–23-Containing Tn2008 in Carbapenem-Resistant Acinetobacter baumannii Isolates Grouped in CC92 from China

    Science.gov (United States)

    Chen, Yisheng; Gao, Jing; Zhang, Haomin; Ying, Chunmei

    2017-01-01

    The rapid expansion of carbapenem-resistant Acinetobacter baumannii (CRAB) clinical isolates is a big issue. We investigated the antibiotic susceptibility, molecular epidemiology and resistance gene of A. baumannii collected at two hospitals in Shanghai, China. Besides, the A. baumannii PCR-based replicon typing method (AB-PBRT) was conducted to categorize the plasmids into homogeneous groups on the basis of replicase genes. Most CRAB isolates showed high-level resistance to almost all antibiotics but retain susceptibility to colistin and tigecycline. A total of 101 isolates carried blaOXA-51-like gene. Sequencing identified the presence of blaOXA-66 for CRAB isolates. blaOXA–23 gene were discovered in all CRAB isolates. Each CRAB isolate contained 1–3 of 19 different plasmid replicase (rep) gene homology groups (GRs) and the GR6 (repAci6) was ubiquitous. Genotyping by Multilocus Sequence Typing (MLST) showed seven defined MLST patterns and three novel STs were found. eBURST analysis indicated they were all grouped in CC92 (GCII) with the most frequent ST208 (50%). Two blaOXA–23-bearing transposons were found: Tn2006 and Tn2008. Tn2008 were detected in 54 (96.4%) isolates and Tn2006 in two remaining isolates. The blaOXA–23 carbapenem gene was vitally associated with repAci6 plasmid belong to CC92 clonal group. Our survey revealed severe drug resistance in A. baumannii isolates. Tn2008-containing CC92 A. baumannii were endemic, which may facilitate the blaoxa23 dissemination. PMID:28220115

  5. 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

  6. Acinetobacter baumannii neonatal mastitis: a case report.

    Science.gov (United States)

    Mohr, Emma L; Berhane, Abeba; Zora, John Gregory; Suchdev, Parminder S

    2014-09-25

    Neonatal mastitis is a rare infection. When it does occur, infants younger than 2 months of age are typically affected and the majority of cases are caused by Staphylococcus aureus. We present the first reported case of neonatal mastitis caused by Acinetobacter baumannii, an unusual organism for this type of infection. A 15-day-old full-term Caucasian male neonate presented to our emergency room following fever at home and was admitted for routine neonatal sepsis evaluation. After admission, he developed purulent drainage from his right nipple, was diagnosed with mastitis, and was started on empiric therapy with clindamycin and cefotaxime with presumed coverage for S. aureus. Drainage culture identified pan-susceptible Acinetobacter baumannii/haemolyticus and antibiotic therapy was changed to ceftazidime. He was discharged after 5 days of ceftazidime with complete resolution of his symptoms. This case illustrates the importance of obtaining drainage cultures in mastitis cases because of the possibility of organisms besides S. aureus causing infection. Acinetobacter baumannii is considered part of the normal human flora and is associated with serious infections in intensive care units. This is the first case report describing Acinetobacter baumannii as an etiologic agent of neonatal mastitis and highlights the importance of including unusual organisms in the differential for infectious etiologies for general practitioners.

  7. 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

  8. 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.

  9. Characteristics of antibiotic resistance and sequence type of Acinetobacter baumannii clinical isolates in Japan and the antibacterial activity of DS-8587.

    Science.gov (United States)

    Higuchi, Saito; Shikata, Mototsugu; Chiba, Megumi; Hoshino, Kazuki; Gotoh, Naomasa

    2014-04-01

    DS-8587 is a novel broad-spectrum fluoroquinolone with extended antimicrobial activity against both Gram-positive and Gram-negative pathogens. In this study, we evaluated the antibacterial activity and mechanism of DS-8587 in 31 quinolone-resistant Acinetobacter baumannii clinical isolates. Efflux pump and qnr genes, mutations in quinolone resistance-determining regions of target enzymes, and sequence types determined by multilocus sequence typing were analyzed. Forty-two quinolone-susceptible clinical isolates were analyzed for comparison. For susceptibility testing, DS-8587 exhibited more effective antibacterial activity when compared with ciprofloxacin and levofloxacin. When combined with the efflux pump inhibitor 1-(1-napthylmethyl)-piperazine, the MIC of DS-8587 was less affected when compared with the MIC exhibited by combined ciprofloxacin and 1-(1-napthylmethyl)-piperazine. The efflux pump genes adeA/adeB/adeC and regulatory elements adeR/adeS were detected in 23 of 31 quinolone-resistant isolates. The qnrA/qnrB/qnrS genes were not detected in any A. baumannii isolates analyzed. Mutations in quinolone resistance-determining regions were observed in all 31 quinolone-resistant isolates. Multilocus sequence typing analyses revealed that 22 of 31 quinolone-resistant isolates belonged to ST-2, corresponding to international clonal lineage II. In conclusion, DS-8587 exhibits potent antibacterial activity against quinolone-resistant A. baumannii isolates that harbor mutations in quinolone resistance-determining regions. In the presence of the efflux pump inhibitor 1-(1-napthylmethyl)-piperazine, no significant changes were observed in the MIC for DS-8587. DS-8587 should be considered as a treatment option for A. baumannii including ST-2 strains that are predominant among the quinolone-resistant A. baumannii isolates found in Japan. Copyright © 2013 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd

  10. 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.

  11. [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.

  12. Nickel biosorption by Acinetobacter baumannii and Pseudomonas aeruginosa isolated from industrial wastewater Bioadsorção de niquel por Acinetobacter baumannii e Pseudomonas aeruginosa isoladas de águas residuais industriais

    Directory of Open Access Journals (Sweden)

    Carlos E. Rodríguez

    2006-12-01

    Full Text Available Nickel biosorption ability was evaluated in two bacterial strains: Acinetobacter baumannii UCR-2971 and Pseudomonas aeruginosa UCR-2957, resulting in greatest adsorption at pH 4.5 and a residence time of 100 minutes. Biosorption isotherms showed that the process follows the Langmuir model. The maximum adsorption rates (Nmax were 8.8 and 5.7 mg·g-1 for A. baumannii and P. aeruginosa, respectively; however, affinity constants suggest that P. aeruginosa (K=1.28 has higher affinity for nickel than A. baumannii (K=0.68. It is suggested that both strains could be used for wastewater treatment, as long as the concentration of Ni2+ is within the range of mg·L-1.Foi avaliada a capacidade de adsorção do Ni2+ por duas bactérias, Acinetobacter baumannii e Pseudomonas aeruginosa, em pH 4.5 com tempo de contato de 100 minutos. Isotermas de adsorção foram calculadas com as duas linhagens. Observou-se que, para ambas, o processo de adsorção está de acordo com o modelo fisicoquímico de Langmuir. A captação máxima do Ni2+ (Nmax foi 5.7 e 8.8 mg Ni2+ g-1 para P. aeruginosa e A. baumannii, respectivamente. Não obstante, P. aeruginosa apresenta uma constante de afinidade (K=1.28 maior que A. baumannii (K=0.68. Estes resultados indicam que ambas as linhagens são adequadas para o tratamento de águas contaminadas, desde que a concentração de níquel seja da ordem de mg·L-1.

  13. Antimicrobial Resistance Patterns of Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus Isolated From Patients With Nosocomial Infections Admitted to Tehran Hospitals

    Directory of Open Access Journals (Sweden)

    Fallah

    1970-01-01

    Full Text Available Background Nosocomial infections constitute a global health problem, leading to a high rate of morbidity and mortality. The choice of antimicrobial treatment for nosocomial infections is often empirical and based on the knowledge of local antimicrobial activity patterns of the most common bacteria causing such infections. Objectives The aim of this study was to determine the 3 most prevalent bacterial pathogens including Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus causing nosocomial infections and their antimicrobial resistant profiles in patients admitted to three hospitals in Tehran city, Iran. Materials and Methods In this cross-sectional study, the A. baumannii, P. aeruginosa and S. aureus isolates were obtained from different samples of patients with nosocomial infections admitted to different wards of three hospitals including Milad, Motahary and Loghman from November 2014 to April 2015. Nosocomial infections were defined as a culture-proven infection, which occurred more than 48 hours after admission. Antimicrobial susceptibility testing was performed using the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI guidelines. Results In total, 539 samples were collected during the study period from patients with nosocomial infections. Overall, 198, 75 and 98 A. baumannii, P. aeruginosa and S. aureus isolates were obtained, respectively. Cefepim and meropenem were found to be the most effective antibiotics for nosocomial infections caused by S. aureus with only 1 resistant isolate. Resistance to gentamicin and amikacin and susceptibility to cefepim was the highest compared to other antibiotics amongst P. aeruginosa isolates which is in consistent with the fact that cephalosporins remain useful agents for the management of nosocomial infections caused by P. aeruginosa. Acinetobacter baumannii isolates showed lower susceptibility rates to imipenem and ciprofloxacin than other

  14. 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.

  15. Phenotypic Detection of Metallo-Beta-Lactamases in Carbapenem Resistant Acinetobacter baumannii Isolated from Pediatric Patients in Pakistan

    Directory of Open Access Journals (Sweden)

    Muneeza Anwar

    2016-01-01

    Full Text Available Multidrug resistant A. baumannii has emerged as an important and problematic human pathogen as it is the causative agent of several types of infections especially in neonates and immunocompromised patients because they have least capacity to fight against infections. Carbapenems are used as last resort antibiotics for treating these infections but currently resistance against carbapenems due to MBL production is on the rise. The objective of this study was to determine the frequency of antibiotic resistance in A. baumannii and also to compare the efficacy of combined disk test and double disk synergy test for detection of metallo-beta-lactamases. A total of 112 A. baumannii were identified from various clinical samples and antibiotic susceptibility profile was determined by Kirby-Bauer Disk Diffusion method. Out of 112, 66 (58.9% isolates were resistant to both imipenem and meropenem (OXOID. These resistant isolates were tested for carbapenemase production, and 55 (83.3% were carbapenemase producers by Modified Hodge Test. These isolates were further tested for MBL production by combined disk test and double disk synergy test. Out of 66, 49 isolates were positive by both methods, CDT and DDST, and only one isolate was detected as negative (with kappa value = 0.038. All MBL producing strains showed remarkable resistance to cephalosporins, fluoroquinolones, aminoglycosides, and piperacillin/tazobactam (OXOID. The antibiotic resistance was very high in A. baumannii which were isolated from children in Pakistan specially attending a nephrology unit.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. Molecular detection of AdeABC efflux pump genes in clinical isolates of Acinetobacter baumannii and their contribution in imipenem resistance

    Directory of Open Access Journals (Sweden)

    Ali Reza JaponiNejad

    2014-11-01

    Full Text Available Backgrand: Multi-drug resistance due to Acinetobacter baumannii strains has become a significant challenge. Efflux pump plays a vital role in the development of resistance in this bacteria. The aim of this study was to evaluate the frequency of the AdeABC efflux pump genes and its role in resistance to imipenem in clinical isolates of A.baumannii. Materials and methods: A total of 56 isolates of A.baumannii were collected from different clinical specimens of Valiasr hospital in the Arak –Iran and all isolates were identified by standard biochemical tests. The Antimicrobial susceptibility patterns were determined by disk diffusion method and minimum inhibitory concentrations of imipenemin via E-test strips with and without CCCP efflux pump inhibitor were determined according to CLSI guidelines. The PCR test was used to detect the AdeABC efflux pump genes in isolates. Results: All A.bumannii isolates were resistant to cefotaxim, ceftazidim, cefepim, cefoxitin, azteronam, piperacillin-tazobactam and ciprofloxacin, as well as all isolates were resistant to imipenem according to the results of the E-test method. Imipenem MIC with efflux pump inhibitor not reduced in all isolates and showed no differences in imipenem activity. The adeA, adeB and adeC genes were found in 100%, 100% and 96.5% of isolates, respectively. Conclusion: AdeABC efflux system contributes to resistance to other antibiotics and resistance to imipenem has not been involved with this efflux system in A.baumanni isolates in current study and other mechanism such as carbapenemase enzymes play vital role to imipenem resistance in A.baumanni isolates.

  1. Prevalence of 16S rRNA methylase, modifying enzyme, and extended-spectrum beta-lactamase genes among Acinetobacter baumannii isolates.

    Science.gov (United States)

    Liu, Zhenru; Ling, Baodong; Zhou, Liming

    2015-08-01

    Multidrug-resistant Acinetobacter baumannii has become a worldwide problem, and methylation of 16S rRNA has recently emerged as a new mechanism of resistance to aminoglycosides, which is mediated by a newly recognized group of 16S rRNA methylases. 16S rRNA methylase confers a high-level resistance to all 4,6-substituted deoxystreptamine aminoglycosides that are currently used in clinical practice. Some of the A. baumannii isolates have been found to coproduce extended-spectrum beta-lactamases (ESBLs), contributing to their multidrug resistance. The aim of this study was to detect the determinants of the 16S rRNA methylase genes armA, rmtA, rmtB, rmtC, rmtD, rmtE, and npmA, the modifying enzyme genes aac(6')-Ib, ant(3″)-Ia, aph(3')-I, and the extended-spectrum beta-lactamase genes bla(TEM), bla(SHV), and bla(CTX-M-3) among A. baumannii isolates in northeastern Sichuan, China. Minimum inhibitory concentrations (MICs) of 21 different antimicrobial agents against the A. baumannii isolates were determined. The clinical isolates showed a high level of resistance (MIC≧256 μg/ml) to aminoglycosides, which ranged from 50·1 to 83·8%. The resistances to meropenem and imipenem, two of the beta-lactam antibiotics and the most active antibiotics against A. baumannii, were 9·1 and 8·2%, respectively. Among 60 amikacin-resistant isolates, only the 16S rRNA methylase gene armA was found to be prevalent (66·7%), but the other 16S rRNA methylase genes rmtA, rmtB, rmtC, rmtD, rmtE, and npmA were not detected. The prevalences of the modifying enzyme genes aac (6')-Ib, ant (3″)-Ia, and aph (3')-I were 51·7, 81·7, and 58·3%, respectively, which are different from a previous study in which the occurrences of these genes were 3, 64, and 72%, respectively. Among the 40 isolates that were armA-positive, the prevalences of bla(TEM), bla(SHV), and bla(CTX-M-3) genes were detected for the first time in China, and their occurrences were 45, 65, and 52·5%, respectively. In all, A

  2. 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

  3. Outbreak of extensively drug-resistant Acinetobacter baumannii indigo-pigmented strains

    OpenAIRE

    Vilacoba, Elisabet; Almuzara, Marisa; Gulone, Lucia; Rodriguez, Rocio; Pallone, Elida; Bakai, Romina; Centron, Daniela; Ramirez, Maria Soledad

    2016-01-01

    Acinetobacter baumannii pigmented strains are not common in clinical settings. In the present work we report an outbreak caused by indigo-pigmented A. baumannii strains isolated in an acute hospital in Argentina from March to September 2012. Pan-PCR assays exposed a unique pattern belonging to the recently described regional CC113B/CC79P that confirms the relevant relationships among the indigo-pigmented A. baumannii strains. All of them were extensively drug-resistant and harbored different ...

  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. Co-occurrence of blaNDM-1 with blaOXA-23 or blaOXA-58 in clinical multidrug-resistant Acinetobacter baumannii isolates in Algeria.

    Science.gov (United States)

    Ramoul, Abir; Loucif, Lotfi; Bakour, Sofiane; Amiri, Sabrina; Dekhil, Mazouz; Rolain, Jean-Marc

    2016-09-01

    The aim of this study was to characterise the mechanisms of carbapenem resistance in Acinetobacter baumannii strains isolated in an Algerian hospital. A total of 43 imipenem-resistant A. baumannii clinical isolates collected between 2010 and 2013 were identified using API 20NE and were confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed by the disk diffusion and Etest methods. Carbapenemase activity was detected using microbiological tests and PCR. Genetic transfer of the blaNDM-1 gene was performed by conjugation using sodium azide-resistant Escherichia coli J53 as recipient strain. Clonal relationships were studied by multilocus sequence typing (MLST) using partial sequences of the csuE and blaOXA-51 genes. All 43 A. baumannii isolates were resistant to imipenem with high minimum inhibitory concentrations (MICs) (>32μg/mL). The strains harboured blaOXA-23, blaNDM-1, blaOXA-58 and/or blaOXA-24 genes. Co-existence of blaNDM-1 and blaOXA-23 or blaOXA-58 was detected in two isolates and one isolate, respectively. NDM-1 plasmid transfer to E. coli J53 was successful only for one of the three strains harbouring both blaNDM-1 and blaOXA-23 or blaOXA-58. The phylogenetic tree obtained from concatenation of the partial sequences of csuE and blaOXA-51 showed that there was no genetic relationship between the isolates and the blaNDM-1 resistance gene. Here we report for the first time the co-occurrence of blaNDM-1 along with blaOXA-23 or blaOXA-58 in recent clinical isolates of A. baumannii from Northeast Algeria. These findings re-emphasise the dissemination and rapid spread of blaNDM-1 carbapenemase genes in multidrug-resistant clinical A. baumannii isolates in Algeria.

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Isolation and characterization of φkm18p, a novel lytic phage with therapeutic potential against extensively drug resistant Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Gwan-Han Shen

    Full Text Available AIMS: To isolate phages against extensively drug resistant Acinetobacter baumannii (XDRAB and characterize the highest lytic capability phage as a model to evaluate the potential on phage therapy. METHODS AND RESULTS: Eight phages were isolated from hospital sewage and showed narrow host spectrum. Phage φkm18p was able to effectively lyse the most XDRAB. It has a dsDNA genome of 45 kb in size and hexagonal head of about 59 nm in diameter and no tail. Bacterial population decreased quickly from 10(8 CFU ml(-1 to 10(3 CFU ml(-1 in 30 min by φkm18p. The 185 kDa lysis protein encoded by φkm18p genome was detected when the extracted protein did not boil before SDS-PAGE; it showed that the lysis protein is a complex rather than a monomer. Phage φkm18p improved human lung epithelial cells survival rates when they were incubated with A. baumannii. Combination of phages (φkm18p, φTZ1 and φ314 as a cocktail could lyse all genotype-varying XDRAB isolates. CONCLUSION: Infections with XDRAB are extremely difficult to treat and development of a phage cocktails therapy could be a therapeutic alternative in the future. Phage φkm18p is a good candidate for inclusion in phage cocktails.

  15. Effect of iron on expression of efflux pump (adeABC) and quorum sensing (luxI, luxR) genes in clinical isolates of Acinetobacter baumannii.

    Science.gov (United States)

    Modarresi, Farzan; Azizi, Omid; Shakibaie, Mohammad Reza; Motamedifar, Mohammad; Valibeigi, Behnaz; Mansouri, Shahla

    2015-11-01

    Resistance-nodulation-division efflux system (RND) adeABC contributes to intrinsic resistance to various drug classes in Acinetobacter baumannii. Similarly, quorum sensing (QS) plays an important role in the biofilm formation and pathogenicity of this bacterium. The aims of this study were to evaluate the influence of iron limitation on the expression of efflux pump (adeABC) genes and QS (luxI, luxR) system by relative quantitative real-time polymerase chain reaction (qRT-PCR). In addition, DNA sequence and phylogenetic relatedness of biofilm-associated protein (Bap) gene was also investigated. Sixty-five multidrug-resistant isolates of A. baumannii were recovered from ICU patients of three hospitals in Kerman, Iran. The isolates were highly resistant to at least 11 antibiotics (MIC ≥64 μg/mL); however, 87% and 89% were susceptible to colistin and tigecycline, respectively (MIC 0.05 μg/mL) (p ≤ 0.05). We detected the presence of RND efflux pump, QS, and bap genes with the frequencies of 92% (adeA), 61.5% (adeB), 84.6% (adeC), 80% (luxI), 61% (luxR), and 66% (bap), respectively. qRT-PCR analysis showed that in some isolates, expression of both adeABC and luxI/R was increased more than fourfold in the presence of low iron (20 μm), suggesting the additional regulatory role of iron on both efflux pump and QS system. Alignment and phylogenetic analysis on the strong biofilm forming isolates confirmed that the fragments amplified were indeed part of bap gene and deduced sequence was similar to A. baumannii K9B410.

  16. 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.

  17. [Carbapenem-resistant Acinetobacter baumannii strains].

    Science.gov (United States)

    Bogiel, Tomasz; Kwiecińska-Piróg, Joanna; Jachna-Sawicka, Katarzyna; Gospodarek, Eugenia

    2010-01-01

    A. baumannii rods are opportunistic pathogens responsible generally for nosocomial infections. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to evaluate the frequency of isolation and susceptibility to antibiotics of resistant to imipenem and/or meropenem A. baumannii strains isolated between 2007 and 2009 from patients of University Hospital of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń. Study shows increasing frequency of isolation that type of strains from 4 in 2007 to 95 in 2008 and 67 in 2009. Percentage of imipenem-resistant isolates raised to 27.6% in 2008 and 31.0% in 2009. Meropenem-resistant A. baumannii isolates frequency changed from 2.1% in 2007 to 31.2% and 34.6%, in 2008 and 2009, respectively. The majority of strains were obtained from patients of the Intensive Care Units and surgery clinics. Examined A. baumannii strains were generally isolated from bronchoalveolar lavage (25.3%) and wound (18.1%) or throat (12.0%) swabs samples. The isolates demonstrated full resistance to norfloxacin, ciprofloxacin, and chloramphenicol. Ampicillin/sulbactam (24.8%), tobramycin (8.1%) and colistin (1.5%) presented the highest in vitro activity against isolated strains.

  18. The pmrCAB operon mediates polymyxin resistance in Acinetobacter baumannii ATCC 17978 and clinical isolates through phosphoethanolamine modification of lipid A.

    Science.gov (United States)

    Arroyo, Luis A; Herrera, Carmen M; Fernandez, Lucia; Hankins, Jessica V; Trent, M Stephen; Hancock, Robert E W

    2011-08-01

    The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA. Knockout of the pmrB gene in two mutants and two clinical isolates led to a decrease in the polymyxin B susceptibility of these strains, which could be restored with the cloned pmrAB genes from the mutants but not from the wild type. Reverse transcription-quantitative PCR (RT-qPCR) analysis also showed a correlation between the expression of pmrC and polymyxin B resistance. Characterization of lipid A species from the mutant strains, by thin-layer chromatography and mass spectrometry, indicated that the addition of phosphoethanolamine to lipid A correlated with resistance. This addition is performed in Salmonella enterica serovar Typhimurium by the product of the pmrC gene, which is a homolog of the pmrC gene from Acinetobacter. Knockout of this gene in the mutant R2 [pmrB(T235I)] reversed resistance as well as phosphoethanolamine modification of lipid A. These results demonstrate that specific alterations in the sequence of the pmrCAB operon are responsible for resistance to polymyxins in A. baumannii.

  19. The pmrCAB Operon Mediates Polymyxin Resistance in Acinetobacter baumannii ATCC 17978 and Clinical Isolates through Phosphoethanolamine Modification of Lipid A▿

    Science.gov (United States)

    Arroyo, Luis A.; Herrera, Carmen M.; Fernandez, Lucia; Hankins, Jessica V.; Trent, M. Stephen; Hancock, Robert E. W.

    2011-01-01

    The emergence of multidrug resistance among Acinetobacter baumannii is leading to an increasing dependence on the use of polymyxins as last-hope antibiotics. Here, we utilized genetic and biochemical methods to define the involvement of the pmrCAB operon in polymyxin resistance in this organism. Sequence analysis of 16 polymyxin B-resistant strains, including 6 spontaneous mutants derived from strain ATCC 17978 and 10 clinical isolates from diverse sources, revealed that they had independent mutations in the pmrB gene, encoding a sensor kinase, or in the response regulator PmrA. Knockout of the pmrB gene in two mutants and two clinical isolates led to a decrease in the polymyxin B susceptibility of these strains, which could be restored with the cloned pmrAB genes from the mutants but not from the wild type. Reverse transcription-quantitative PCR (RT-qPCR) analysis also showed a correlation between the expression of pmrC and polymyxin B resistance. Characterization of lipid A species from the mutant strains, by thin-layer chromatography and mass spectrometry, indicated that the addition of phosphoethanolamine to lipid A correlated with resistance. This addition is performed in Salmonella enterica serovar Typhimurium by the product of the pmrC gene, which is a homolog of the pmrC gene from Acinetobacter. Knockout of this gene in the mutant R2 [pmrB(T235I)] reversed resistance as well as phosphoethanolamine modification of lipid A. These results demonstrate that specific alterations in the sequence of the pmrCAB operon are responsible for resistance to polymyxins in A. baumannii. PMID:21646482

  20. Nosocomial Acinetobacter baumannii Infections and Changing Antibiotic Resistance.

    Science.gov (United States)

    Necati Hakyemez, Ismail; Kucukbayrak, Abdulkadir; Tas, Tekin; Burcu Yikilgan, Aslihan; Akkaya, Akcan; Yasayacak, Aliye; Akdeniz, Hayrettin

    2013-09-01

    In the intensive care setting, Acinetobacter baumannii causes ventilator-associated pneumonia and other nosocomial infections that are difficult to treat. Objective of this study was to investigate nosocomial A. baumannii infections and its changing antibiotic resistance. A total of 56 patients diagnosed with A.baumannii infections between January 2009 and December 2011 were included in the study. Diagnosis for nosocomial infections was established according to the CDC (Centers for Disease Control and Prevention) criteria. Identification of the agents isolated was carried out using conventional methods and VITEK 2 automated system, while antibiotic sensitivity testing was performed through VITEK 2 AST-N090 automated system. The most common infection was nosocomial pneumonia by 43%, among which 46% were ventilator-associated pneumonia. Considering all years, the most effective antibiotics on the isolated strains were found as colistin, tigecycline, imipenem and meropenem. However resistance to imipenem and meropenem was observed to increase over years. The issue of increased resistance to antibiotics poses difficulty in treatment of A. baumannii infections which in turn increases the rate of mortality and cost. In order to prevent development of resistance, antibiotics must be used in an appropriate way in accompanied with proper guidance.

  1. Genomic sequencing of a strain of Acinetobacter baumannii and potential mechanisms to antibiotics resistance.

    Science.gov (United States)

    Zhao, Lei; Li, Hongru; Zhu, Ziwen; Wakefield, Mark R; Fang, Yujiang; Ye, Ying

    2017-06-01

    Acinetobacter baumannii has been becoming a great challenge to clinicians due to their resistance to almost all available antibiotics. In this study, we sequenced the genome from a multiple antibiotics resistant Acinetobacter baumannii stain which was named A. baumannii-1isolated from China by SMRT sequencing technology to explore its potential mechanisms to antibiotic resistance. We found that several mechanisms might contribute to the antibiotic resistance of Acinetobacter baumannii. Specifically, we found that SNP in genes associated with nucleotide excision repair and ABC transporter might contribute to its resistance to multiple antibiotics; we also found that specific genes associated with bacterial DNA integration and recombination, DNA-mediated transposition and response to antibiotics might contribute to its resistance to multiple antibiotics; Furthermore, specific genes associated with penicillin and cephalosporin biosynthetic pathway and specific genes associated with CHDL and MBL β-lactamase genes might contribute to its resistance to multiple antibiotics. Thus, the detailed mechanisms by which Acinetobacter baumannii show extensive resistance to multiple antibiotics are very complicated. Such a study might be helpful to develop new strategies to control Acinetobacter baumannii infection. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. 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.

  3. Beta-Lactamase Encoded Genes blaTEM and blaCTX Among Acinetobacter baumannii Species Isolated From Medical Devices of Intensive Care Units in Tehran Hospitals

    Science.gov (United States)

    Khalilzadegan, Sara; Sade, Mojtaba; Godarzi, Hussein; Eslami, Gita; Hallajzade, Masoumeh; Fallah, Fatemeh; Yadegarnia, Davood

    2016-01-01

    Background Excessive consumption of antimicrobial materials in hospitals is considered as the main encoder leading to the emergence, development and acquisition of new bacterial resistance to beta-lactamase. Objectives Owing to the lack of proper information regarding the mechanism of the bacterial resistance to antibiotics and responsible genes in the country, the current study aimed to consider the resistance or sensitivity of the Acinetobacter baumannii multi drug resistant (MDR) isolates facing 2% glutaraldehyde. The study was conducted in the selected intensive care units in Tehran hospitals, Iran, in 2013. Materials and Methods In this study conducted over a period of 10 months, A. baumannii species were isolated by bacterial culture following biochemical tests from intensive care units (ICUs) of some hospitals in Tehran, Iran (Fayazbaksh, Taleghani, Imam Khomeini, Valiasr, Labafinejad). The resistance and sensitivity of the isolates to antibiotics were considered according to the clinical and laboratory standard institute CLSI (2012) guidelines. By multiplex PCR method, blaCTX and blaTEM genes were detected and finally, MDR strains were treated with 2% glutaraldehyde. PCR was used for each strain of MDR using specific primers. Results In the current study, 131 A. baumannii isolates (22.3%) out of 588 were studied. The level of resistance to various antibiotics was in the range of 69.4% to 100%. The frequencies of blaTEM and blaCTX genes were 3.2% and 19.4%, respectively. MIC50% and MIC90% of imipenem and meropenem antibiotics were 32 ± 1 µg/mL and 64 ± 1 µg/mL, respectively (P < 0.9). However no resistance to glutaraldehyde was observed. Different bands of MDR strains were observed in the PCR product by electrophoresis. Conclusions It seems that besides the variety and prevalence of blaTEM and blaCTX, enormous mechanisms such as porin and leaking systems (efflux pumps) are responsible for the information of the A. baumannii resistance to disinfectants

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Sandra Yamile Saavedra

    Full Text Available 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.

  6. Study of the effect of essential oil of Salvia glutinosa L. on microbial biofilm formation by clinical isolates of Acinetobacter baumannii

    Science.gov (United States)

    Tutar, Uǧur

    2016-04-01

    Acinetobacter baumannii is becoming a serious concern in the treatment of infections that can develop resistance to many antibiotics. This persistence may be explained by its capacity to form biofilms. In our study, the essential oil (EO) of the Salvia glutinosa plant, was obtained through the hydrodistillation method. Antimicrobial and antibiofilm activities of the EO on the 20 multi-drug resistant (MDR) A.baumannii isolates were researched. Broth microdilution methods were applied for the determination of the antimicrobial activity. For the determined antibiofilm activity, the Minimal Biofilm Inhibition Concentration (MBIC) test was implemented with the microtiter plate method. Photometric assay was applied for the identification of the antioxidant capacity and colorimetric assay was used to specify the cytotoxicity of the EO of S. glutinosa on L929 cells. In our study, Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values between 1.25-2.5 µl/mL and 5-10 µl/mL respectively. MBIC value of the EO was found as 0.3-2.5 µl/mL. IC50= = 24.4±0.66 µl/mL was found as the antioxidant capacity of the EO. At 25%, 12.5% and 6.25% EO concentrations, no cytotoxicity appeared for the fibroblast cells in terms of the cytotoxic activities (p>0.05). According to the findings obtained in our study, antibiofilm, antimicrobial and antioxidant activities of the S. glutinosa EO seem remarkable. These findings seem promising for the development of potential phytotherapeutic agents in the treatment of the multi-drug resistance (MDR) A.baumannii infections.

  7. Analysis on drug-resistance and molecular epidemiology of Acinetobacter baumannii isolated from the clinical samples in two Chinese hospitals

    Institute of Scientific and Technical Information of China (English)

    WEI FENG SHI; ZHI MI HUANG; NING XU

    2006-01-01

    In the present study, the drug-resistance genes encoding β-lactamases, aminoglycoside modifying enzymes, DNA topoisomerases and integron as well as their molecular epidemiology were investigated by means of analyzing the drug-resistance and molecular epidemiology of Acinebacter baumannii isolated from the clinical samples in two hospitals in Changzhou and Huzhou city of Jiangsu and Zhejiang province from July 2000 to March 2005. The minimal inhibitory concentrations (MICs) of these 307 isolates were detected by automatic microbiological system, and 35 strains against 5-fluoroquinolones were performed by agar dilution assay. Meanwhile, the resistant genes in 80 isolates were amplified by PCR with identification by DNA sequencer. It was found that most of the 307 isolates of A. baumannii were resistant to multiple antibiotics tested, in which the resistance rates of the isolates against piperacillin, piperacillin/tazobactam, amoxacillin/clavulanic acid, cefotaxime, ceftazidime,cefepime, gentamicin, amikacin, ciprofloxacin, chloramphenicol and sulfamethoxazole/trimethoprim were all above 35%, but those of imipenem and meropenem were quite low, ranged only 2.6% and 3.3 %. In addition, it was also demonstrated that the positive rates of TEM and SHV β-lactamase genes accounted for 93.8% and 22.5% respectively, and those of the aminoglycoside-modifying enzyme genes including aacC1, aacC2, aacC3, aacC4, aacC4A, aphA6, ant(2")-Ⅰ and ant(3")-Ⅰ were 58.8%, 8.8%, 7.5%, 28.8%, 45.0%, 2.5%, 28.8% and 65.0% respectively. The mutations in the quinolone-resistant determining region (QRDR) of gyrA and parC genes indicated that substitution in Ser-83 residue of GyrA protein was most frequently occurred among strains with MIC for ciprofloxacin of more than 4 μg/ml, whereas a double mutation at Ser-83 residue of gyrA and Ser-80 of parC was found in strains with MIC of ciprofloxacin of more than 8 μg/ml. As to the positive rates of class 1 integron (Int Ⅰ -1) and qacE△1-sul

  8. 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...

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

    Directory of Open Access Journals (Sweden)

    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.  

  10. 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.

  11. Detection of disinfectant-resistant gene in acinetobacter baumannii isolated in clinic%临床分离鲍曼不动杆菌耐消毒剂基因携带情况分析及消毒对策

    Institute of Scientific and Technical Information of China (English)

    于文静; 闻海丰; 秦瑾; 冯忠军

    2014-01-01

    Objective To investigate the drug resistance characteristics of acinetobacter baumannii isolated in clinic and the disinfectant-resistant gene (qacEΔ1-sul1) taken along with acinetobacter baumannii ,and to explore its sensitivity to chlorine-containing disinfectant .Methods Antibiotic susceptibility was detected by Kirby -Bauer agar scrip diffusion method.Polymerase chain reaction (PCR) was used to examine qacEΔ1-sul1 and broth dilution method was used to determine the minimum inhibitory concentration .Results Among the clinically isolated 73 strains of acinetobacter baumannii ,37 strains were found to be positive in qacEΔ1-sul1gene, and positive rate was 50.68%.The average MIC of chlorine-containing disinfectant to acinetobacter baumannii was 365.07mg/L.Conclusion Clinically isolated acinetobacter baumannii is multidrug resistant bacteria , and its qacEΔ1-sul1 positive rate is higher , but the chlorine-containing disinfectant in practical concentration can kill acinetobacter baumannii .%目的:了解临床分离的鲍曼不动杆菌的耐药特性和耐消毒剂基因qacEΔ1-sul1的携带情况及其对含氯消毒剂的敏感性。方法采用K-B琼脂纸片扩散法检测抗菌药物的敏感性,采用聚合酶链反应( PCR)检测耐消毒剂基因qacEΔ1-sul1,用肉汤稀释法检测菌株的最低抑菌浓度( MIC)。结果73株鲍曼不动杆菌中,37株(50帋.68%) qacEΔ1-sul1阳性,含氯消毒剂对鲍曼不动杆菌的平均MIC 值为365.07 mg/L。结论临床分离的鲍曼不动杆菌为多重耐药菌,qacEΔ1-sul1基因携带率较高,但临床常用浓度的含氯消毒剂可将鲍曼不动杆菌杀灭。

  12. 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.

  13. 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...

  14. Nosocomial Acinetobacter baumannii Infections and Changing Antibiotic Resistance

    OpenAIRE

    Necati Hakyemez, Ismail; Kucukbayrak, Abdulkadir; Tas, Tekin; Burcu Yikilgan, Aslihan; Akkaya, Akcan; Yasayacak, Aliye; Akdeniz, Hayrettin

    2013-01-01

    Objectives: In the intensive care setting, Acinetobacter baumannii causes ventilator-associated pneumonia and other nosocomial infections that are difficult to treat. Objective of this study was to investigate nosocomial A. baumannii infections and its changing antibiotic resistance. Methods: A total of 56 patients diagnosed with A.baumannii infections between January 2009 and December 2011 were included in the study. Diagnosis for nosocomial infections was established according to the CDC (C...

  15. 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.

  16. 湖南衡阳地区鲍曼不动杆菌的分布和耐药性分析%Analysis on the distribution and antibiotic resistance of Acinetobacter baumannii isolated in Hengyang region, Hunan

    Institute of Scientific and Technical Information of China (English)

    任林; 陈超群; 张秋桂; 谢海涛

    2012-01-01

    OBJECTIVE To investigate the distribution and antibiotic resistance of Acinetobacter baumannii during the last four years in our hospital for the purpose of providing reference for rational use of antibiotics. METHODS The strains isolated from the specimens of the inpatients in our hospital were collected from January 2007 to December 2010. The API system was used to identify the pathogenic bacteria and conduct antibiotic susceptibility test. The results were analyzed with WHONET 5.4 software. RESULTS Acinetobacter baumannii was mainly isolated from sputum, and the samples were mainly obtained from ICU. Except sensitive to imipenem and meropenem, Acinetobacter baumannii to the other antibiotics resistance rate was high. The drug resistance rate of Acinetobacter baumannii to imipenem and meropenem in ICU was higher than that in the general ward. CONCLUSION Acinetobacter baumannii is majorly caused respiratory tract infection of inpatients in ICU and neurosurgery. And the resistance rate of Acinetobacter baumannii is very serious.%目的 了解某院近4年鲍曼不动杆菌的感染分布及其耐药性,为临床合理用药提供依据.方法 收集该院2007年1月~2010年12月住院患者送检标本,采用API鉴定系统进行菌株鉴定及药敏试验,用WHONET 5.4分析试验结果.结果 该院鲍曼不动杆菌主要分离自痰标本,以重症监护病房(ICU)最多见.鲍曼不动杆菌除对亚胺培南和美罗培南耐药率较低外,对其他抗菌药物耐药率均较高.在ICU分离的鲍曼不动杆菌对亚胺培南和美罗培南的耐药率明显高于普通病房.结论 鲍曼不动杆菌感染主要引起ICU和神经外科病房患者的呼吸道感染,且耐药性十分严重.

  17. 2007~2010年长沙市某医院鲍曼不动杆菌的分离情况及耐药性分析%Isolation and Drug Resistance of Acinetobacter Baumannii in 2007~2010

    Institute of Scientific and Technical Information of China (English)

    汤渝玲; 周志国; 李榜龙; 李科宇; 王建湘

    2011-01-01

    [Objective] To investigate the diversity of antibiotic resistance of acinetobacter baumannii isolated in our hospital and provide the reference for the rational use of antibiotics. [Methods] Acinetobacter baumannii isolated from the clinical specimens of the inpatients in our hospital between 2007 and 2010 were analyzed retrospectively. [Results] In the recent 4 years, the constituent ratio of infections caused by acinetobacter baumannii ( P <0. 01). Meanwhile, the resistance to antimicrobial drugs increased significantly ( P < 0. 01). But imipenem and Polymyxin still had good antibacterial effect for acinetobacter baumannii(R<30%). [Conclusion] Acinetobacter baumannii is one of the fundamental composition of clinical pathogenic bacteria. The resistance rate of acinetobacter baumannii to common antibiotics increases year by year. The rate of multi-drug resistance also increases obviously. Antibiotics should be rationally applied in order to reduce the production of multidrug resistant strains.%[目的]了解本医院住院患者鲍曼不动杆菌的耐药性变迁,为临床合理使用抗菌药物提供依据.[方法]对2007~2010年本院住院患者各类标本分离的鲍曼不动杆菌进行回顾性统计分析.[结果]近4年来,鲍曼不动杆菌感染占临床分离革兰阴性杆菌的构成比逐年增加(P<0.01),对抗菌药物的耐药性显著提高,但亚胺培南、多粘菌素对鲍曼氏不动杆菌仍有较好的抗菌作用(耐受率<30%).[结论]鲍曼不动杆菌是临床病原菌的重要组成之一,其对临床常用抗菌药物的耐药性呈逐年上升趋势,多重耐药菌比例明显增加.应重视合理使用抗生素,减少多重耐药菌株的产生.

  18. The complete genome and phenome of a community-acquired Acinetobacter baumannii.

    Science.gov (United States)

    Farrugia, Daniel N; Elbourne, Liam D H; Hassan, Karl A; Eijkelkamp, Bart A; Tetu, Sasha G; Brown, Melissa H; Shah, Bhumika S; Peleg, Anton Y; Mabbutt, Bridget C; Paulsen, Ian T

    2013-01-01

    Many sequenced strains of Acinetobacter baumannii are established nosocomial pathogens capable of resistance to multiple antimicrobials. Community-acquired A. baumannii in contrast, comprise a minor proportion of all A. baumannii infections and are highly susceptible to antimicrobial treatment. However, these infections also present acute clinical manifestations associated with high reported rates of mortality. We report the complete 3.70 Mbp genome of A. baumannii D1279779, previously isolated from the bacteraemic infection of an Indigenous Australian; this strain represents the first community-acquired A. baumannii to be sequenced. Comparative analysis of currently published A. baumannii genomes identified twenty-four accessory gene clusters present in D1279779. These accessory elements were predicted to encode a range of functions including polysaccharide biosynthesis, type I DNA restriction-modification, and the metabolism of novel carbonaceous and nitrogenous compounds. Conversely, twenty genomic regions present in previously sequenced A. baumannii strains were absent in D1279779, including gene clusters involved in the catabolism of 4-hydroxybenzoate and glucarate, and the A. baumannii antibiotic resistance island, known to bestow resistance to multiple antimicrobials in nosocomial strains. Phenomic analysis utilising the Biolog Phenotype Microarray system indicated that A. baumannii D1279779 can utilise a broader range of carbon and nitrogen sources than international clone I and clone II nosocomial isolates. However, D1279779 was more sensitive to antimicrobial compounds, particularly beta-lactams, tetracyclines and sulphonamides. The combined genomic and phenomic analyses have provided insight into the features distinguishing A. baumannii isolated from community-acquired and nosocomial infections.

  19. Phenotypic detection of metallo-β-lactamases in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from hospitalized patients in São Luis, State of Maranhão, Brazil

    Directory of Open Access Journals (Sweden)

    Roberto Morais Luz de Carvalho

    2013-07-01

    Full Text Available Introduction Acquired metallo-β-lactamases (MβL are emerging determinants of resistance in Pseudomonas aeruginosa and Acinetobacter baumannii. The objectives of this study were to phenotypically detect MβL in imipenem-resistant P. aeruginosa and A. baumannii, to investigate the association between MβL-positive strains and hospitals, and to compare the resistance profiles of MβL-producing and non-MβL-producing strains. Methods The approximation disk and combined disk assay methods were used in this study. Results A total of 18 (38.3% P. aeruginosa isolates and 1 (5.6% A. baumannii isolate tested positive for the presence of MβL. Conclusions These results demonstrate the need for strict surveillance and for the adoption of preventive measures to reduce the spread of infection and potential outbreaks of disease caused by MβL-producing microorganisms.

  20. 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...

  1. 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.

  2. RND-type efflux pumps in multidrug-resistant clinical isolates of Acinetobacter baumannii: major role for AdeABC overexpression and AdeRS mutations.

    Science.gov (United States)

    Yoon, Eun-Jeong; Courvalin, Patrice; Grillot-Courvalin, Catherine

    2013-07-01

    Increased expression of chromosomal genes for resistance-nodulation-cell division (RND)-type efflux systems plays a major role in the multidrug resistance (MDR) of Acinetobacter baumannii. However, the relative contributions of the three most prevalent pumps, AdeABC, AdeFGH, and AdeIJK, have not been evaluated in clinical settings. We have screened 14 MDR clinical isolates shown to be distinct on the basis of multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) for the presence and overexpression of the three Ade efflux systems and analyzed the sequences of the regulators AdeRS, a two-component system, for AdeABC and AdeL, a LysR-type regulator, for AdeFGH. Gene adeB was detected in 13 of 14 isolates, and adeG and the intrinsic adeJ gene were detected in all strains. Significant overexpression of adeB was observed in 10 strains, whereas only 7 had moderately increased levels of expression of AdeFGH, and none overexpressed AdeIJK. Thirteen strains had reduced susceptibility to tigecycline, but there was no correlation between tigecycline MICs and the levels of AdeABC expression, suggesting the presence of other mechanisms for tigecycline resistance. No mutations were found in the highly conserved LysR regulator of the nine strains expressing AdeFGH. In contrast, functional mutations were found in conserved domains of AdeRS in all the strains that overexpressed AdeABC with two mutational hot spots, one in AdeS near histidine 149 suggesting convergent evolution and the other in the DNA binding domain of AdeR compatible with horizontal gene transfer. This report outlines the high incidence of AdeABC efflux pump overexpression in MDR A. baumannii as a result of a variety of single mutations in the corresponding two-component regulatory system.

  3. 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.

  4. 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

  5. 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.

  6. 北京某院2014年鲍曼不动杆菌的耐药性分析%Drug resistance ananlysis of Acinetobacter baumannii strains isolated during 2014 in a hospital of Beijing

    Institute of Scientific and Technical Information of China (English)

    邢献国; 杜新; 孟岩

    2015-01-01

    目的:了解该院2014年临床分离鲍曼不动杆菌对各类抗菌药物的耐药性,以指导临床合理用药。方法按常规方法进行细菌培养,对临床分离病原菌进行鉴定和药敏试验,使用 Whonet5.6软件进行数据统计分析。结果该院2014年1~12月共分离到鲍曼不动杆菌226株,该菌对米诺环素、头孢哌酮/舒巴坦耐药率最低,分别为23.0%和30.1%,对其他抗菌药物的耐药率均高于50.0%。不同科室分离株对抗菌药物的耐药率不同,其中以 ICU 分离株耐药率最高。多重耐药和泛耐药鲍曼不动杆菌分别达到了71.2%、19.0%。结论鲍曼不动杆菌对多种抗菌药物耐药率高,应加强鲍曼不动杆菌耐药性监测,隔离泛耐药鲍曼不动杆菌感染者,防止医院内传播。%Objective To investigate the drug resistance of Acinetobacter baumannii strains isolated during 2014 in a hospital of Beijing.Methods Isolated bacteria were cultured by routine method,identified and performed drug susceptibility test by bacteria a-nalysis system.Statistical analysis of Acinetobacter baumannii was conducted by Whonet5.6 software.Results A total of 226 Acin-etobacter baumannii strains were isolated from January 2014 to December 2014 in Fengtai Teaching Hospital of Capital Medical U-niversity.These strains showed the lowest resistance rates to minocycline and Cefoperazone-sulbactam(23.0% and 30.1%).The other antimicrobial resistance rates were more than 50.0%.The resistance rate of Acinetobacter baumannii varied from one depart-ment to another.Pandrug-resistant and multi-drug resistant Acinetobacter baumannii were 71.2%,1 9.0% respectively. Conclusion The resistant rates of Acinetobacter baumannii strains to a variety of antibiotics are high.It is essential to strengthen monitoring the drug resistance of Acinetobacter baumannii,as well as use antibiotics reasonable and separate patients to control Acinetobacter baumannii infection.

  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. Detection of blaNDM, blaDIM, blaIMP, blaVIM and blaCTX-M-15 beta-lactamase Genes among Pseudomonas aeruginosa and Acinetobacter baumannii Strains Isolated from Two Hospitals of Tehran, Iran

    Directory of Open Access Journals (Sweden)

    Tahere Farajzadeh Alan

    2016-10-01

    Full Text Available Background: In this study, we evaluated the existence of blaNDM ,  blaDIM, blaIMP, blaVIM, blaCTX-M-15 beta-lactamase  genes among Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from hospitalized patients.Materials and Methods: From June 2013 to May 2014, thirty-four nonduplicate nonconsecutive isolates of A. baumannii and P. aeruginosa were isolated from blood, respiratory tract, wound, sputum and urine samples of patients from hospitalized in two hospitals in Tehran, Iran. Antibiotic susceptibility test was performed by Kirby-Bauer disc diffusion method according to CLSI guidelines. In this study, the frequency of MBL (metallo-beta-lactamase producers was evaluated by CDDT (Combined disk diffusion test and prevalence of blaNDM, blaDIM, blaIMP, blaVIM and blaCTX-M-15  genes were evaluated  by PCR and sequencing methods among P. aeruginosa and  A. baumannii strains isolated from  hospitalized patient of Tehran during 2013 -2014 years.Results: Of thirty-four non-fermenter isolates, 24 (70.58% P. aeruginosa and 10 (29.41% as A. baumannii were isolated and identified. High rate of resistance to common antibiotics were detected specially among A. baumannii isolates that showed 100% resistance to 4 of tested antibiotics. The CDDT results reveal that 4 (16.66% of the P. aeruginosa isolates and 1 (10% of the A.baumannii were positive for production of MBLs. The prevalence of blaCTX-M-15 gene among 10 A. baumannii isolates was 4 (40%, and for IMP-1, 2 (20%. The OXA-51 has been investigated and was detected in all A. baumannii isolates. Also the prevalence of blaCTX-M-15 gene among 24 P.aeruginosa isolates was 11 (45.83%, and for IMP-1, 3(12.5%. Fortunately, NDM, blaVIM, blaDIM gene was not detected in all isolates.Conclusion: The detection of MBL-producing A. baumannii and P. aeruginosa strains detected in this research is of great concern and highlights the need of infection control measures, including antimicrobial

  9. 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.

  10. Structure of ADC-68, a novel carbapenem-hydrolyzing class C extended-spectrum β-lactamase isolated from Acinetobacter baumannii.

    Science.gov (United States)

    Jeon, Jeong Ho; Hong, Myoung Ki; Lee, Jung Hun; Lee, Jae Jin; Park, Kwang Seung; Karim, Asad Mustafa; Jo, Jeong Yeon; Kim, Ji Hwan; Ko, Kwan Soo; Kang, Lin Woo; Lee, Sang Hee

    2014-11-01

    Outbreaks of multidrug-resistant bacterial infections have become more frequent worldwide owing to the emergence of several different classes of β-lactamases. In this study, the molecular, biochemical and structural characteristics of an Acinetobacter-derived cephalosporinase (ADC)-type class C β-lactamase, ADC-68, isolated from the carbapenem-resistant A. baumannii D015 were investigated. The blaADC-68 gene which encodes ADC-68 was confirmed to exist on the chromosome via Southern blot analysis and draft genome sequencing. The catalytic kinetics of β-lactams and their MICs (minimum inhibitory concentrations) for A. baumannii D015 and purified ADC-68 (a carbapenemase obtained from this strain) were assessed: the strain was resistant to penicillins, narrow-spectrum and extended-spectrum cephalosporins, and carbapenems, which were hydrolyzed by ADC-68. The crystal structure of ADC-68 was determined at a resolution of 1.8 Å. The structure of ADC-68 was compared with that of ADC-1 (a non-carbapenemase); differences were found in the central part of the Ω-loop and the C-loop constituting the edge of the R1 and R2 subsites and are close to the catalytic serine residue Ser66. The ADC-68 C-loop was stabilized in the open conformation of the upper R2 subsite and could better accommodate carbapenems with larger R2 side chains. Furthermore, a wide-open conformation of the R2-loop allowed ADC-68 to bind to and hydrolyze extended-spectrum cephalosporins. Therefore, ADC-68 had enhanced catalytic efficiency against these clinically important β-lactams (extended-spectrum cephalosporins and carbapenems). ADC-68 is the first reported enzyme among the chromosomal class C β-lactamases to possess class C extended-spectrum β-lactamase and carbapenemase activities.

  11. Extremely high prevalence of antiseptic resistant Quaternary Ammonium Compound E gene among clinical isolates of multiple drug resistant Acinetobacter baumannii in Malaysia

    OpenAIRE

    Babaei, Mohammad Reza; Sulong, Anita; Hamat, Rukman Awang; Nordin, Syafinaz Amin; Neela, Vasantha Kumari

    2015-01-01

    Background Antiseptics are commonly used for the management of MDR (multiple drug resistance) pathogens in hospitals. They play crucial roles in the infection control practices. Antiseptics are often used for skin antisepsis, gauze dressing, preparation of anatomical sites for surgical procedure, hand sterilization before in contact with an infected person, before an invasive procedure and as surgical scrub. Methods We screened 122 multiple drug resistant Acinetobacter baumannii (MDRAB) isola...

  12. Prevalence of Genes of OXA-23 Carbapenemase and AdeABC Efflux Pump Associated with Multidrug Resistance of Acinetobacter baumannii Isolates in the ICU of a Comprehensive Hospital of Northwestern China.

    Science.gov (United States)

    Jia, Wei; Li, Caiyun; Zhang, Haiyun; Li, Gang; Liu, Xiaoming; Wei, Jun

    2015-08-21

    The objective of this study was to explore the molecular epidemiology and the genetic support of clinical multidrug resistant (MDR) Acinetobacter baumannii (A. baumannii) isolates in an ICU ward of a comprehensive hospital. A total of 102 non-duplicate drug-resistant A. baumannii isolates were identified and 93 (91.1%) of them were MDR strains. Molecular analysis demonstrated that carbapenemase genes blaOXA-23 and blaOXA-51 were presented in all 93 MDR isolates (100%), but other carbapenemase genes, including blaOXA-24, blaOXA-58, blaIMP-1, blaIMP-4, blaSIM, and blaVIM genes were completely absent in all isolates. In addition, genes of AdeABC efflux system were detected in 88.2% (90/102) isolates. Interestingly, an addition to efflux pump inhibitor, reserpine could significantly enhance the susceptibility of MDR isolates to moxifloxacin, cefotaxime, and imipenem (p baumannii, and the co-expression of oxacillinase and efflux pump proteins are thus considered to be the important reason for the prevalence of this organism in the ICU of this hospital.

  13. In vitro antimicrobial synergy studies of carbapenem-resistant Acinetobacter baumannii isolated from intensive care units of a tertiary care hospital in Egypt.

    Science.gov (United States)

    Nageeb, Wedad; Metwally, Lobna; Kamel, Mahmoud; Zakaria, Sahar

    2015-01-01

    The increasing prevalence of multidrug-resistant and pan drug-resistant Acinetobacter baumannii as a cause of nosocomial infections has led to the need for the reassessment of novel combinations of antibiotics as our only current viable option for handling such infections until a new therapeutic option becomes available. Two of the most commonly used methods for testing antimicrobial synergy are the Time-kill assay method and the E-test method, and these were the methods used in this study. Antibiotic combinations tested in this study were azithromycin and polymyxin, tobramycin and polymyxin, polymyxin and rifampicin, and tobramycin and rifampicin. The azithromycin and polymyxin combination showed synergy, while the rifampicin and polymyxin combination showed antagonism. The synergy was achieved at lower MIC values than using each of the single agents alone against the same isolates. Synergy testing results varied according to the method used, and it is difficult to establish which method is more accurate. The use of these lower MIC values as a guide to determine effective therapeutic doses used in combination therapy can help to decrease the emergence of resistance and can also minimize the side effects associated with using a single agent at a higher dose. Further research is still required to predict in vivo efficacy of such combinations.

  14. In vitro activity of aminoglycosides against clinical isolates of Acinetobacter baumannii complex and other nonfermentative Gram-negative bacilli causing healthcare-associated bloodstream infections in Taiwan.

    Science.gov (United States)

    Liu, Jyh-You; Wang, Fu-Der; Ho, Mao-Wang; Lee, Chen-Hsiang; Liu, Jien-Wei; Wang, Jann-Tay; Sheng, Wang-Huei; Hseuh, Po-Ren; Chang, Shan-Chwen

    2016-12-01

    Aminoglycosides possess in vitro activity against aerobic and facultative Gram-negative bacilli. However, nationwide surveillance on susceptibility data of Acinetobacter baumannii complex and Pseudomonas aeruginosa to aminoglycosides was limited, and aminoglycoside resistance has emerged in the past decade. We study the in vitro susceptibility of A. baumannii complex and other nonfermentative Gram-negative bacilli (NFGNB) to aminoglycosides. A total of 378 NFGNB blood isolates causing healthcare-associated bloodstream infections during 2008 and 2013 at four medical centers in Taiwan were tested for their susceptibilities to four aminoglycosides using the agar dilution method (gentamicin, amikacin, tobramycin, and isepamicin) and disc diffusion method (isepamicin). A. baumannii was highly resistant to all four aminoglycosides (range of susceptibility, 0-4%), whereas >80% of Acinetobacter nosocomialis and Acinetobacter pittii blood isolates were susceptible to amikacin (susceptibility: 96% and 91%, respectively), tobramycin (susceptibility: 92% and 80%, respectively), and isepamicin (susceptibility: 96% and 80%, respectively). All aminoglycosides except gentamicin possessed good in vitro activity (>94%) against P. aeruginosa. Amikacin has the best in vitro activity against P. aeruginosa (susceptibility, 98%), followed by A. nosocomialis (96%), and A. pittii (91%), whereas tobramycin and isepamicin were less potent against A. pittii (both 80%). Aminoglycoside resistances were prevalent in Stenotrophomonas maltophilia and Burkholderia cepacia complex blood isolates in Taiwan. Genospecies among the A. baumannii complex had heterogeneous susceptibility profiles to aminoglycosides. Aminoglycosides, except gentamicin, remained good in vitro antimicrobial activity against P. aeruginosa. Further in vivo clinical data and continuous resistance monitoring are warranted for clinical practice guidance. Copyright © 2015. Published by Elsevier B.V.

  15. 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.

  16. 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.

  17. 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

  18. Nosocomial Infections Caused by Acinetobacter baumannii: Are We Losing the Battle?

    Science.gov (United States)

    Protic, Dragana; Pejovic, Aleksa; Andjelkovic, Dragana; Djukanovic, Nina; Savic, Dragana; Piperac, Pavle; Markovic Denic, Ljiljana; Zdravkovic, Marija; Todorovic, Zoran

    2016-04-01

    The incidence of nosocomial infections caused by multi-drug- and extended-drug resistant strains of Acinetobacter is constantly increasing all over the world, with a high mortality rate. We analyzed the in-hospital data on the sensitivity of Acinetobacter baumannii isolates and correlated them with antibiotic treatment and clinical outcomes of nosocomial infections over a 17-mo period. Retrospective analysis was performed at the Clinical Center "Bezanijska kosa," Belgrade, Serbia. Microbiologic data (number and sensitivity of A. baumannii isolates) and clinical data (medical records of 41 randomly selected patients who developed nosocomial infection caused by A. baumannii) were matched. Acinetobacter baumannii, detected in 279 isolates and obtained from 19 patients (12% of all samples), was resistant to almost all antibiotics tested, including carbapenems, with the exception of colistin and tigecycline. It was obtained most often from the respiratory tract samples. Empiric treatment of the nosocomial infections (pneumonia in 75% of cases) involved cephalosporins, metronidazole, and carbapenems (80%, 66%, and 61% of patients, respectively), whereas tigecyclin and colistin were used primarily in targeted therapy (20% and 12% of patients, respectively). The mortality rate of patients treated empirically was significantly higher (p Nosocomial A. baumannii infections represent a significant clinical problem because of their high incidence, lack of susceptibility to the most commonly used antibiotics, and the often inappropriate treatment, which favors the development of multi-drug-resistant strains.

  19. Isolated from ICU secondary infection in different samples of Acinetobacter baumannii resistance analysis%从ICU 继发感染者不同标本中分离鲍曼不动杆菌耐药性分析

    Institute of Scientific and Technical Information of China (English)

    温国辉

    2015-01-01

    目的:分析从IC U重症患者不同标本类型中分离出的鲍曼不动杆菌的耐药性差异,为有效预防和控制IC U内鲍曼不动杆菌感染提供依据。方法回顾性分析本院2010年1月至2014年12月住院IC U患者送检标本中分离的568株鲍曼不动杆菌临床资料。结果从IC U感染患者中分离的鲍曼不动杆菌主要来源为痰液(60.0%);药敏试验表明鲍曼不动杆菌对常用抗菌药物的耐药率呈普遍多重耐药,对替加环素、头孢哌酮/舒巴坦最敏感,耐药率小于40.0%;从痰液和无菌体液中分离的鲍曼不动杆菌对亚胺培南、美罗培南、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、环丙沙星、左氧氟沙星、阿米卡星的耐药率普遍高于血液和尿液,差异有统计学意义(P<0.05)。结论鲍曼不动杆菌对常用抗菌药物多重耐药,在ICU中不同标本类型的耐药性存在差异,临床必须加强耐药性监测,治疗该菌感染时首选替加环素、头孢哌酮/舒巴坦。%Objective Analysis isolated from ICU patients with severe types of different samples of Acinetobacter baumannii re‐sistance difference ,for effective prevention and control of Acinetobacter baumannii infection in ICU .Methods Retrospective analy‐sis of the college from January 2010 to December 2014 568 strains isolated from hospitalized ICU patients samples Acinetobacter baumannii clinical data .Results Isolated from ICU patients infected with Acinetobacter baumannii main source of sputum (60 .0% );drug sensitive test showed that Acinetobacter baumannii resistance to commonly used antimicrobial agents were generally multiple drug resistance ,the most sensitive to tigecycline ,cefoperazone/sulbactam ,resistance rate of less than 40 .0% ;isolated from sputum and sterile body fluid in Acinetobacter baumannii was generally higher than that of blood and urine to imipenem ,meropen‐em ,cefoperazone

  20. ANTIMICROBIAL SENSITIVITY OF MULTIDRUG-RESISTANT ACINETOBACTER BAUMANNII IN A TERTIARY CARE HOSPITAL OF PATNA

    Directory of Open Access Journals (Sweden)

    Keshav Kumar Bimal

    2017-06-01

    Full Text Available BACKGROUND Acinetobacter spp. has emerged as an important nosocomial pathogen especially in ICU settings. Acinetobacter baumannii is the most commonly isolated species among different Acinetobacters and is associated with variety of human infections. A. baumannii exhibits resistance not only to beta-lactams and cephalosporins, but also to other groups of antibiotics including carbapenems and this has resulted in the emergence of multidrug-resistance A. baumannii species, which is now widespread. To know the prevalence and antimicrobial susceptibility pattern of A. baumannii is crucial for the optimal antimicrobial therapy and to resist the spread of MDR Acinetobacter spp. The aim of the study is to study the antimicrobial susceptibility pattern of A. baumannii isolated from various clinical specimens and to explore the risk factors for multidrug-resistant A. baumannii infections. MATERIALS AND METHODS The present study was conducted from August 2015 to July 2016 at Indira Gandhi Institute of Medical Sciences, Patna. Antimicrobial susceptibility testing was done by Kirby-Bauer’s disc diffusion method. The zones of inhibition were interpreted for antibiotic sensitivity as per the CLSI guidelines 2014. Data regarding patients demographic and clinical status was obtained from medical records and possible risk factors for multidrug-resistant A. baumannii infections was evaluated for their statistical significance. Statistical analysis used- Microsoft excel sheet 2007 and Epi Info software (version 7.2.0.1 was used for different statistical analysis including Pearson’s x 2 test and simple logistic regression. RESULTS A. baumannii was isolated predominantly from respiratory samples (35.3%. Majority of the isolates were from different inpatient departments (59.1%, followed by different ICUs (40.9%. The A. baumannii isolates showed most sensitivity to colistin (100% followed by polymyxin B (90.20% and least sensitive to ampicillin (5.19%. Most of the

  1. 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.

  2. 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

  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. The population structure of Acinetobacter baumannii: expanding multiresistant clones from an ancestral susceptible genetic pool.

    Directory of Open Access Journals (Sweden)

    Laure Diancourt

    Full Text Available Outbreaks of hospital infections caused by multidrug resistant Acinetobacter baumannii strains are of increasing concern worldwide. Although it has been reported that particular outbreak strains are geographically widespread, little is known about the diversity and phylogenetic relatedness of A. baumannii clonal groups. Sequencing of internal portions of seven housekeeping genes (total 2,976 nt was performed in 154 A. baumannii strains covering the breadth of known diversity and including representatives of previously recognized international clones, and in 19 representatives of other Acinetobacter species. Restricted amounts of diversity and a star-like phylogeny reveal that A. baumannii is a genetically compact species that suffered a severe bottleneck in the recent past, possibly linked to a restricted ecological niche. A. baumannii is neatly demarcated from its closest relative (genomic species 13TU and other Acinetobacter species. Multilocus sequence typing analysis demonstrated that the previously recognized international clones I to III correspond to three clonal complexes, each made of a central, predominant genotype and few single locus variants, a hallmark of recent clonal expansion. Whereas antimicrobial resistance was almost universal among isolates of these and a novel international clone (ST15, isolates of the other genotypes were mostly susceptible. This dichotomy indicates that antimicrobial resistance is a major selective advantage that drives the ongoing rapid clonal expansion of these highly problematic agents of nosocomial infections.

  5. Association between mutations in gyrA and parC genes of Acinetobacter baumannii clinical isolates and ciprofloxacin resistance

    Directory of Open Access Journals (Sweden)

    Abdollah Ardebili

    2015-06-01

    Conclusion: Simultaneous mutations in gyrA and parC genes are expected to play a major role in high-level fluoroquinolone resistance in A. baumannii; albeit a single mutation in DNA topoisomerase IV could occasionally be associated with intermediate-resistance to these antimicrobials.

  6. 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...

  7. 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...

  8. 不同时间段临床分离的鲍曼不动杆菌的耐药性及分布%Drug-resistance and distribution of Acinetobacter baumannii isolated in clinical at different times

    Institute of Scientific and Technical Information of China (English)

    李琳

    2014-01-01

    目的:分析院内不同时间段临床分离的鲍曼不动杆菌的耐药性及标本来源,以指导临床合理使用抗菌药物。方法对2012年10月至2012年12月(2012年第4季度)分离的157株鲍曼不动杆菌、2013年1月至2013年3月(2013年第1季度)分离的184株鲍曼不动杆菌、2013年4月至2013年6月(2013年第2季度)分离的127株鲍曼不动杆菌、2013年7月至2013年9月(2013年第3季度)分离的154株鲍曼不动杆菌,用WalkAway 96 PLUS NC50药敏板检测菌株对亚胺培南等13种抗菌药物的耐药性,并对检测结果分别进行分析。结果2012年第4季度和2013年第1季度分离的鲍曼不动杆菌对阿米卡星的耐药率分别为33.8%(53/157)和39.1%(72/184),对妥布霉素的耐药率分别为43.9%(69/157)和46.7%(86/184),对复方新诺明、环丙沙星、左氧氟沙星、头孢吡肟、庆大霉素、头孢他啶、哌拉西林、哌拉西林/他唑巴坦、头孢噻肟、亚胺培南和美罗培南耐药率为50.3%~93.5%,2013年第2季度和2013年第3季度对亚胺培南等13种抗菌药物的耐药率为44.8%~66.1%。不同阶段分离的鲍曼不动杆菌90.91%~95.54%的标本来源于痰液。结论连续4个季度监测本院院内分离的鲍曼不动杆菌对临床常用抗菌药物耐药率均很高,临床医师应根据药敏试验治疗鲍曼不动杆菌引起的感染。%Objective To investigate the drug-resistance and specimen source of Acinetobacter baumannii isolated in clinical at different times, so as to guide the clinical rational use of antimicrobial drugs. Methods Total of 157 strains of Acinetobacter baumannii were isolated from October 2012 to December 2012 (the fourth quarter of 2012), 184 strains of Acinetobacter baumannii isolated from January 2013 to March 2013 (the ifrst quarter of 2013), 127 strains of Acinetobacter baumannii isolated from April 2013 to June 2013 (the second quarter of 2013) and 154 strains of

  9. Drug resistance of carbapenems - resistant Acinetobacter baumannii isolates and detection of metallo - β - lactamase%我院耐碳青霉烯类鲍曼不动杆菌的耐药性分析

    Institute of Scientific and Technical Information of China (English)

    雷红; 黄留玉; 董梅

    2011-01-01

    目的 了解我院耐碳青霉烯类鲍曼不动杆菌的耐药性及其产金属β-内酰胺酶(MBLs)菌株的情况.方法 采用MicroScan WalkAway 96检测耐碳青霉烯类鲍曼不动杆菌对23种抗菌药物的耐药性;采用Etest MBLs检测耐碳青霉烯类鲍曼不动杆菌产金属β3-内酰胺酶.结果 42株耐碳青霉烯类鲍曼不动杆菌仅对头孢派酮/舒巴坦和米诺环素耐药率较低,分别为16%和32%;对氨曲南、阿米卡星、头孢噻肟、头孢他啶等21种抗菌药物高度耐药,耐药率均为93%以上.42株中有40株产金属β-内酰胺酶,其检出率为95%.结论 耐碳青霉烯类鲍曼不动杆菌耐药现象极其严重,甚至呈泛耐药;产金属β-内酰胺酶是耐碳青霉烯类鲍曼不动杆菌的重要耐药机制之一;临床应根据药敏结果合理选用抗菌药物.%Objective To investigate the resistance characteristics of carbapenems - resistant Acinetobacler baumannii in clinical isolates and the production of metallo - β - lactamase. Methods Antimicrobial susceptibility was tested by McrioScan WalkAway 96. E test was used to screen metallo - β - laclamase positive isolates from carbapenems - resistant Acinetobacter baumannii. Results The resistance rate to sulperazone and minocyciine was as low as 16% and 32% repectively. Carbapenems - resistant Acinetobacter baumannii showed strong resistance to a variety of antibiotics. The rate of resistance was over 93.0% . A total of 42 carbapenems - resistant Acinetobacler baumannii were isolated. In addition, 40 of the 42 carbapenems - resistant Acinetobacter baumannii were identified with metallo - β - lactamase. Conclusions Carbapenems - resistant Acinetobacter baumannii is pan - drug resistant.. The production of metallo - lactamase represents one of the main mechanisms of resistance to carbapenems in Acinetobacter baumannii, suggesting that more attention should be. Paid to the resistance of Acinetohacter baumannii ant! Reasonable

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Lul Raka

    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.

  12. 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.

  13. Insufficient Discriminatory Power of Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry Dendrograms to Determine the Clonality of Multi-Drug-Resistant Acinetobacter baumannii Isolates from an Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    John Hoon Rim

    2015-01-01

    Full Text Available While pulsed-field gel electrophoresis (PFGE is recognized as the gold standard method for clonality analysis, MALDI-TOF MS has recently been spotlighted as an alternative tool for species identification. Herein, we compared the dendrograms of multi-drug-resistant (MDR Acinetobacter baumannii isolates by using MALDI-TOF MS with those by using PFGE. We used direct colony and protein extraction methods for MALDI-TOF MS dendrograms. The isolates with identical PFGE patterns were grouped into different branches in MALDI-TOF MS dendrograms. Among the isolates that were classified as very close isolates in MALDI-TOF MS dendrogram, PFGE band patterns visually showed complete differences. We numeralized similarity among isolates by measuring distance levels. The Spearman rank correlation coefficient values were 0.449 and 0.297 between MALDI-TOF MS dendrogram using direct colony and protein extraction method versus PFGE, respectively. This study is the first paper focusing solely on the dendrogram function of MALDI-TOF MS compared with PFGE. Although MALDI-TOF MS is a promising tool to identify species in a rapid manner, our results showed that MALDI-TOF MS dendrograms could not substitute PFGE for MDR Acinetobacter baumannii clonality analysis.

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

    Directory of Open Access Journals (Sweden)

    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

  15. 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.

  16. Prevalence of Genes of OXA-23 Carbapenemase and AdeABC Efflux Pump Associated with Multidrug Resistance of Acinetobacter baumannii Isolates in the ICU of a Comprehensive Hospital of Northwestern China

    Directory of Open Access Journals (Sweden)

    Wei Jia

    2015-08-01

    Full Text Available The objective of this study was to explore the molecular epidemiology and the genetic support of clinical multidrug resistant (MDR Acinetobacter baumannii (A. baumannii isolates in an ICU ward of a comprehensive hospital. A total of 102 non-duplicate drug-resistant A. baumannii isolates were identified and 93 (91.1% of them were MDR strains. Molecular analysis demonstrated that carbapenemase genes blaOXA-23 and blaOXA-51 were presented in all 93 MDR isolates (100%, but other carbapenemase genes, including blaOXA-24, blaOXA-58, blaIMP-1, blaIMP-4, blaSIM, and blaVIM genes were completely absent in all isolates. In addition, genes of AdeABC efflux system were detected in 88.2% (90/102 isolates. Interestingly, an addition to efflux pump inhibitor, reserpine could significantly enhance the susceptibility of MDR isolates to moxifloxacin, cefotaxime, and imipenem (p < 0.01. Clonal relationship analysis further grouped these clinical drug-resistant isolates into nine clusters, and the MDR strains were mainly in clusters A, B, C, and D, which include 16, 13, 25, and 15 isolates, respectively. This study demonstrated that clinical isolates carrying carbapenemase-encoding genes blaOXA-23 and AdeABC efflux pump genes are the main prevalent MDR A. baumannii, and the co-expression of oxacillinase and efflux pump proteins are thus considered to be the important reason for the prevalence of this organism in the ICU of this hospital.

  17. 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.

  18. The complete genome and phenome of a community-acquired Acinetobacter baumannii.

    Directory of Open Access Journals (Sweden)

    Daniel N Farrugia

    Full Text Available Many sequenced strains of Acinetobacter baumannii are established nosocomial pathogens capable of resistance to multiple antimicrobials. Community-acquired A. baumannii in contrast, comprise a minor proportion of all A. baumannii infections and are highly susceptible to antimicrobial treatment. However, these infections also present acute clinical manifestations associated with high reported rates of mortality. We report the complete 3.70 Mbp genome of A. baumannii D1279779, previously isolated from the bacteraemic infection of an Indigenous Australian; this strain represents the first community-acquired A. baumannii to be sequenced. Comparative analysis of currently published A. baumannii genomes identified twenty-four accessory gene clusters present in D1279779. These accessory elements were predicted to encode a range of functions including polysaccharide biosynthesis, type I DNA restriction-modification, and the metabolism of novel carbonaceous and nitrogenous compounds. Conversely, twenty genomic regions present in previously sequenced A. baumannii strains were absent in D1279779, including gene clusters involved in the catabolism of 4-hydroxybenzoate and glucarate, and the A. baumannii antibiotic resistance island, known to bestow resistance to multiple antimicrobials in nosocomial strains. Phenomic analysis utilising the Biolog Phenotype Microarray system indicated that A. baumannii D1279779 can utilise a broader range of carbon and nitrogen sources than international clone I and clone II nosocomial isolates. However, D1279779 was more sensitive to antimicrobial compounds, particularly beta-lactams, tetracyclines and sulphonamides. The combined genomic and phenomic analyses have provided insight into the features distinguishing A. baumannii isolated from community-acquired and nosocomial infections.

  19. 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.

  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. Mobile genetic elements related to carbapenem resistance in Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Mariana Pagano

    Full Text Available Abstract Acinetobacter baumannii is widely recognized as an important pathogen associated with nosocomial infections. The treatment of these infections is often difficult due to the acquisition of resistance genes. A. baumannii presents a high genetic plasticity which allows the accumulation of these resistance determinants leading to multidrug resistance. It is highlighted the importance of the horizontal transfer of resistance genes, through mobile genetic elements and its relationship with increased incidence of multidrug resistant A. baumannii in hospitals. Considering that resistance to carbapenems is very important from the clinical and epidemiological point of view, the aim of this article is to present an overview of the current knowledge about genetic elements related to carbapenem resistance in A. baumannii such as integrons, transposons, resistance islands and insertion sequences.

  2. Changes of drug resistance of Acinetobacter baumannii isolated from our hospital in recent three years%某院近3年鲍曼不动杆菌耐药性变迁

    Institute of Scientific and Technical Information of China (English)

    马明炎; 廖利雅; 熊中政

    2013-01-01

    目的分析垫江县人民医院2010~2012年鲍曼不动杆菌的耐药性变迁,为临床合理用药并有效控制鲍曼不动杆菌感染提供依据。方法针对该院2010~2012年临床分离的鲍曼不动杆菌耐药情况及患者的感染情况进行回顾性统计分析。结果鲍曼不动杆菌的临床分离率从2010年的218例(12.19%)增高到2012年的741例(18.48%)。18种抗菌药物耐药率基本都在70%以上,重症监护病房、神经科等科室出现泛耐药菌株。抗菌药物的选择性压力是细菌发生耐药性变迁的主要动因之一,年龄、基础疾病、住院时间及侵入性操作等是患者感染的高危因素。结论医院应加强医疗环境、医疗器械及医护人员的消毒,加强医院感染监测,合理使用抗菌药物等一系列措施,可有效控制鲍曼不动杆菌的感染。%Objective To analyze the changes of drug resistance of Acinetobacter baumannii in our hospital during 2010-2012 to provide reference for clinical rational drug use and the effective control of Acinetobacter baumannii infection .Methods The drug resistance of Acinetobacter baumannii clinically isolated from 2010 to 2012 and its infection situation were retrospectively performed the statistical analysis .Results The clinical isolation rate of Acinetobacter baumannii in our hospital was increased from 218 cases (12 .19% ) to 741 cases (18 .48% ) in 2012 .The resistance rates of 18 kinds of antibiotics were almost more than 70% ,and pan-drug-resistant Acinetobacter baumannii appeared in some clinical departments ,such as ICU and neurology .The selective pressure of antibiotic was one of the main motive causes of drug resistance change ,and age ,underlying diseases ,duration of hospitalization and invasive procedures were the high risk factors in patients infection .Conclusion Hospital should enhance a series of measures including reinforcing the disinfection of the medical environment

  3. Estudo da Similaridade Genética de Amostras de Acinetobacter baumannii Produtoras de Carbapenemases do Tipo OXA Isoladas em Diversos Hospitais Brasileiros

    OpenAIRE

    Werneck, Jessica Sanchez de Freitas [UNIFESP

    2010-01-01

    In this dissertation we present two studies involving carbapenem-resistant Acinetobacter baumannii clinical isolates due to the production of carbapenems modifying enzymes, the OXA-type carbapenemases. The first study aimed to determine the genetic relationship of multi-drug-resistant A. baumannii producing OXA-23 that was isolated in distinct Brazilian cities. A total of 91 A. baumannii clinical isolates were recovered from 17 medical centers located at eight cities, namely São Paulo (SP), R...

  4. High Frequency of OXA-253-Producing Acinetobacter baumannii in Different Hospitals in Recife, Brazil

    Science.gov (United States)

    de Sá Cavalcanti, Felipe Lira; Mendes-Marques, Carina Lucena; Vasconcelos, Crhisllane Rafaele dos Santos; de Lima Campos, Túlio; Rezende, Antonio Mauro; Xavier, Danilo Elias; Leal, Nilma Cintra; de-Melo-Neto, Osvaldo Pompilio; de Morais, Marcia Maria Camargo

    2016-01-01

    ABSTRACT Here, we report the isolation of 31 Acinetobacter baumannii strains producing OXA-253 in a single large Brazilian city. These strains belonged to five different sequence types (STs), including 4 STs not previously associated with blaOXA-253. In all strains, the blaOXA-253 gene was located in a plasmid within a genetic environment similar to what was found previously in Brazil and Italy. The reported data emphasize the successful transmission of the blaOXA-253 gene through a large area and the tendency for this resistance determinant to remain in the A. baumannii population. PMID:27855080

  5. Ability of bacteriophage in resolving wound infection caused by multidrug-resistant Acinetobacter baumannii in uncontrolled diabetic rats.

    Science.gov (United States)

    Shivaswamy, VinodKumar Chickmangalure; Kalasuramath, Suneeta Basavaraj; Sadanand, Chethan Kumar; Basavaraju, Abhishek Kilagere; Ginnavaram, Varsha; Bille, Sumanth; Ukken, Sanjay Saju; Pushparaj, Usha Nandini

    2015-04-01

    Acinetobacter baumannii, a substantial nosocomial pathogen, has developed resistance to almost all available antimicrobial drugs. Bacteriophage therapy is a possible alternative treatment for multidrug-resistant (MDR) bacterial infections. In this study, we have successfully isolated bacteriophage active against clinical strains of A. baumannii by enrichment from hospital sewage sludge using representatives of those strains. The bacteriophage isolated against A. baumannii formed plaques against beta-lactamases producing strains of A. baumannii. The utility of bacteriophage specific for A. baumannii to resolve wound infection in uncontrolled diabetic rats was evaluated. Five groups of uncontrolled diabetic rats were used. Group I was noninfected (Control), Group II was infected with MDR A. baumannii and challenged with bacteriophage, Group III was infected with MDR A. baumannii, Group IV was infected with MDR A. baumannii and challenged with antibiotic colistin, and Group V consisted of noninfected rats and sprayed with phage (Phage control). A significant decrease in infection, period of epithelization, and wound contraction was observed in the phage-challenged group when compared with antibiotic-treated uncontrolled diabetic rats and the control group. To conclude the study, new insights are provided into the biology of the broad host range of A. baumannii phage, demonstrating that A. baumannii phage has prospects for the treatment of infections caused by the MDR A. baumannii.

  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. 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...

  8. Assessment of Minocycline and Polymyxin B Combination against Acinetobacter baumannii

    Science.gov (United States)

    Bowers, Dana R.; Cao, Henry; Zhou, Jian; Ledesma, Kimberly R.; Sun, Dongxu; Lomovskaya, Olga

    2015-01-01

    Antimicrobial resistance among Acinetobacter baumannii is increasing worldwide, often necessitating combination therapy. The clinical utility of using minocycline with polymyxin B is not well established. In this study, we investigated the activity of minocycline and polymyxin B against 1 laboratory isolate and 3 clinical isolates of A. baumannii. Minocycline susceptibility testing was performed with and without an efflux pump inhibitor, phenylalanine-arginine β-naphthylamide (PAβN). The intracellular minocycline concentration was determined with and without polymyxin B (0.5 μg/ml). Time-kill studies were performed over 24 h using approximately 106 CFU/ml of each strain with clinically relevant minocycline concentrations (2 μg/ml and 8 μg/ml), with and without polymyxin B (0.5 μg/ml). The in vivo efficacy of the combination was assessed in a neutropenic murine pneumonia model. Infected animals were administered minocycline (50 mg/kg), polymyxin B (10 mg/kg), or both to achieve clinically equivalent exposures in humans. A reduction in the minocycline MIC (≥4×) was observed in the presence of PAβN. The intracellular concentration and in vitro bactericidal effect of minocycline were both enhanced by polymyxin B. With 2 minocycline-susceptible strains, the bacterial burden in lung tissue at 24 h was considerably reduced by the combination compared to monotherapy with minocycline or polymyxin B. In addition, the combination prolonged survival of animals infected with a minocycline-susceptible strain. Polymyxin B increased the intracellular concentration of minocycline in bacterial cells and enhanced the bactericidal activity of minocycline, presumably due to efflux pump disruption. The clinical utility of this combination should be further investigated. PMID:25712362

  9. 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

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  12. Comparison of Acinetobacter baumannii isolates from the United Kingdom and the United States that were associated with repatriated casualties of the Iraq conflict.

    Science.gov (United States)

    Turton, Jane F; Kaufmann, Mary E; Gill, Martin J; Pike, Rachel; Scott, Paul T; Fishbain, Joel; Craft, David; Deye, Gregory; Riddell, Scott; Lindler, Luther E; Pitt, Tyrone L

    2006-07-01

    Acinetobacter isolates associated with casualties from the Iraq conflict from the United States were compared with those from the United Kingdom by pulsed-field gel electrophoresis and integron analysis. Representatives of the main outbreak strain associated with casualties from both countries were indistinguishable in DNA profile. Two further outbreak strains were common to both sets of isolates.

  13. 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

  14. 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.

  15. 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.

  16. 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 ...

  17. Bulgecin A as a β-lactam enhancer for carbapenem-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii clinical isolates containing various resistance mechanisms

    Directory of Open Access Journals (Sweden)

    Skalweit MJ

    2016-09-01

    Full Text Available Marion J Skalweit,1–5 Mei Li2 1Department of Medicine, 2Research Section, 3Infectious Diseases Section, Louis Stokes Cleveland Department of Veterans, 4Department of Medicine, 5Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, USA Abstract: Genetic screening of Pseudomonas aeruginosa (PSDA and Acinetobacter ­baumannii (ACB reveals genes that confer increased susceptibility to β-lactams when disrupted, suggesting novel drug targets. One such target is lytic transglycosylase. Bulgecin A (BlgA is a natural product of Pseudomonas mesoacidophila and a lytic transglycosolase inhibitor that works synergistically with β-lactams targeting PBP3 for Enterobacteriaceae. BlgA also weakly inhibits di-Zn2+ metallo-β-lactamases like L1 of Stenotrophomonas maltophilia. We hypothesized that because of its unique mechanism of action, BlgA could restore susceptibility to carbapenems in carbapenem-resistant PSDA (CR-PSDA and carbapenem-resistant ACB, as well as ACB resistant to sulbactam. A BlgA-containing extract was prepared using a previously published protocol. CR-PSDA clinical isolates demonstrating a variety of carbapenem resistance mechanisms (VIM-2 carbapenemases, efflux mechanisms, and AmpC producer expression were characterized with agar dilution minimum inhibitory concentration (MIC testing and polymerase chain reaction. Growth curves using these strains were prepared using meropenem, BlgA extract, and meropenem plus BlgA extract. A concentrated Blg A extract combined with low concentrations of meropenem, was able to inhibit the growth of clinical strains of CR-PSDA for strains that had meropenem MICs ≥8 mg/L by agar dilution, and a clinical strain of an OXA-24 producing ACB that had a meropenem MIC >32 mg/L and intermediate ampicillin/sulbactam susceptibility. Similar experiments were conducted on a TEM-1 producing ACB strain resistant to sulbactam. BlgA with ampicillin/sulbactam inhibited the growth

  18. 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.

  19. 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.

  20. 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.

  1. 337株呼吸道鲍氏不动杆菌体外药敏结果分析%In vitro drug susceptibility of 337 strains of Acinetobacter baumannii isolated from sputum samples

    Institute of Scientific and Technical Information of China (English)

    张齐武; 黄晓文; 牛淼; 刘登科; 王延伟

    2011-01-01

    OBJECTIVE To investigate the drug sensitivity of 337 Acinetobacter baumannii strains isolated from sputum samples to common antibiotics, and then to provide evidence for reasonable use of antibiotics in clinical practice. METHODS The microbial sensitivity tests of the 337 strains of Acinetobacter baumannii isolated from our hospital from Jun 2008 to Dec 2010 were reviewed and analyzed. RESULTS Minocycline, meropenem and imipenem were the top three active agents against A. Baumannii among those antibiotics tested. The sensitivities of A. Baumannii to minocycline, meropenem and imipenem were 86. 4%. 23.. 1%, 22, 3%, respectively. Tetracycline had the highest intermediate sensitive rate (14. 2%) and minocycline the lowest resistance rate (6.5%) among those antibiotics tested. Resistance rates of the other antibiotics fluctuated between 71. 2% ~ 84. 9%. CONCLUSION A. Baumannii is resistant to most antibiotics tested, it should strengthen the monitoring and use antibiotics rationally in accordance with the drug susceptibility.%目的 分析鲍氏不动杆菌的药敏结果,指导临床合理使用抗菌药物.方法 收集并分析2008年6月-2010年12月从临床标本中分离的337株鲍氏不动杆菌药敏资料.结果 鲍氏不动杆菌对米诺环素敏感率最高,达86.4%;美罗培南敏感率23.1%,占第2位;亚胺培南敏感率22.3%,排第3位;四环素中介率最高,为14.2%;米诺环素耐药率最低,为6.5%;其他抗菌药耐药率波动在71.2%~84.9%.结论 鲍氏不动杆菌耐药问题非常严重,应加强监测,根据药敏结果合理使用抗菌药物.

  2. Huellas digitales de cepas de Acinetobacter baumannii procedentes de pacientes hospitalizados en la Caja Petrolera de Salud de Obrajes, mediante el método de Pulsed Field Gel Electrophoresis (PFGE, La Paz, Bolivia. Marzo 2015

    Directory of Open Access Journals (Sweden)

    García-Rada Giovanni

    2017-08-01

    Full Text Available Acinetobacter baumannii, worldwide is considered an opportunistic microorganism, present in several cases of hospital-acquired infections. In the Caja Petrolera de Salud of Obrajes Hospital was made the isolation of four Acinetobacter baumannii strains. Identification was confirmed by biochemical tests. Then, the PFGE molecular technique was applied for the identification of genomic fingerprints using Apa I restriction en-zyme.

  3. 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.

  4. Distribution and molecular profiling of class 1 integrons in MDR Acinetobacter baumannii isolates and whole genome-based analysis of antibiotic resistance mechanisms in a representative strain.

    Science.gov (United States)

    Zhu, Yuying; Yi, Yong; Liu, Fei; Lv, Na; Yang, Xi; Li, Jing; Hu, Yongfei; Zhu, Baoli

    2014-11-01

    The class 1 integron is an important driver of the nosocomial dissemination of multidrug-resistant (MDR) bacteria, such as Acinetobacters. In this study, we characterized the gene cassette arrays of class 1 integrons in Acinetobacter baumannii, where the detailed structure of these integrons for 38 clinical strains was analyzed. The results showed that there are three types of gene cassette arrays that are carried by different class 1 integrons, among them the aac(6')-IId-catB8-aadA1 array was the most prevalent. For detailed analysis of the integron structure, whole genome sequencing was carried out on strain AB16, and it was found that a single integron on its chromosome has a partial Tn21 transposon in its 5' flanking region and two complete copies of the insertion element IS26 in both the 5' and 3' flanking regions, indicating that the integron could be acquired by horizontal gene transfer. Furthermore, there is one resistance island AbaR22, one bla gene containing a transposon, four intrinsic resistant genes and one efflux pump that together confer six types of antibiotic resistance.

  5. Identification of Genomic Species of Acinetobacter Isolated from Burns of ICU Patients.

    Science.gov (United States)

    Shaykh Baygloo, Nima; Bouzari, Majid; Rahimi, Fateh; Abedini, Fereydoon; Yadegari, Sima; Soroushnia, Mohsen; Beigi, Fahimeh

    2015-10-01

    The worldwide emergence of multi-drug resistant (MDR) bacteria in recent years has caused many problems for hospitals and patients, especially intensive care unit patients. Among these clinically important MDR bacteria are Acinetobacter baumannii complex species (A. baumannii, Acinetobacter genomic species 3 and Acinetobacter genomic species 13TU) that cause a wide range of infections. The sequencing and bioinformatics analysis of a part of the Zone 1 of rpoB gene was performed for species identification of Acinetobacter isolates obtained from ICU patients with infected burns hospitalized in a hospital in Isfahan, Iran, over a 9-month period. Antibiotic sensitivity of Acinetobacter isolates was investigated using the disk diffusion method and different classes of antibiotics including amikacin, cefotaxime, ceftriaxone, ciprofloxacin, imipenem and piperacillin. Acinetobacter spp. were isolated from 10 of 80 (12.5%) investigated patients. All of the 10 Acinetobacter isolates were identified as Acinetobacter baumannii and multi-drug resistant according to antibiotic susceptibility tests. Of the Acinetobacter baumannii complex members, only A. baumannii species was identified among the isolates obtained from patients with infected burns in an Isfahan hospital over a 9-month period.

  6. 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.

  7. Bactericidal activity of herbal volatile oil extracts against multidrug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Intorasoot, Amornrat; Chornchoem, Piyaorn; Sookkhee, Siriwoot; Intorasoot, Sorasak

    2017-01-01

    The aim of the study is to investigate the antibacterial activity of 10 volatile oils extracted from medicinal plants, including galangal (Alpinia galanga Linn.), ginger (Zingiber officinale), plai (Zingiber cassumunar Roxb.), lime (Citrus aurantifolia), kaffir lime (Citrus hystrix DC.), sweet basil (Ocimum basilicum Linn.), tree basil (Ocimum gratissimum), lemongrass (Cymbopogon citratus DC.), clove (Syzygium aromaticum), and cinnamon (Cinnamomum verum) against four standard strains of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and 30 clinical isolates of multidrug-resistant A. baumannii (MDR-A. baumannii). Agar diffusion, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) were employed for the determination of bactericidal activity of water distilled medicinal plants. Tea tree oil (Melaleuca alternifolia) was used as positive control in this study. The results indicated the volatile oil extracted from cinnamon exhibited potent antibacterial activity against the most common human pathogens, S. aureus, E. coli, P. aeruginosa, and A. baumannii. Most of volatile oil extracts were less effective against non-fermentative bacteria, P. aeruginosa. In addition, volatile oil extracted from cinnamon, clove, and tree basil possessed potent bactericidal activity against MDR-A. baumannii with MBC90 of 0.5, 1, and 2 mg/mL, respectively. The volatile oil extracts would be useful as alternative natural product for the treatment of the most common human pathogens and MDR-A. baumannii infections.

  8. 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

  9. Control of a Multi-Drug-Resistant Acinetobacter baumannii Outbreak after Orthopedics Department Relocation

    Science.gov (United States)

    Gogou, Vasiliki; Meletis, Georgios; Tsitouras, Dimosthenis

    2013-01-01

    Acinetobacter baumannii clinical isolates have the ability to survive in the hospital niche for prolonged time periods and to develop resistance against multiple antimicrobial agents. Therefore, A. baumannii has emerged as an important cause of nosocomial outbreaks worldwide, especially in critical-care environments such as intensive care units. In the present communication, we report a multi-drug-resistant A. baumannii outbreak that occurred in an orthopedics department in Greece after the admission of a patient previously hospitalized in the intensive care unit of a Greek tertiary care hospital. Despite the implementation of infection control measures, 29 patients were infected, significantly raising their hospitalization periods and treatment costs. Interestingly, the outbreak was put under control after the department’s previously programmed relocation. PMID:27694769

  10. Acinetobacter baumannii in critically ill patients: Molecular epidemiology, clinical features and predictors of mortality.

    Science.gov (United States)

    Garnacho-Montero, José; Gutiérrez-Pizarraya, Antonio; Díaz-Martín, Ana; Cisneros-Herreros, José Miguel; Cano, María Eugenia; Gato, Eva; Ruiz de Alegría, Carlos; Fernández-Cuenca, Felipe; Vila, Jordi; Martínez-Martínez, Luis; Tomás-Carmona, M Del Mar; Pascual, Álvaro; Bou, Germán; Pachón-Diaz, Jerónimo; Rodríguez-Baño, Jesús

    2016-11-01

    The main aim of this study was to assess changes in the epidemiology and clinical presentation of Acinetobacter baumannii over a 10-year period, as well as risk factors of mortality in infected patients. Prospective, multicentre, hospital-based cohort studies including critically ill patients with A. baumannii isolated from any clinical sample were included. These were divided into a first period ("2000 study") (one month), and a second period ("2010 study") (two months). Molecular typing was performed by REP-PCR, PFGE and MSLT. The primary endpoint was 30-day mortality. In 2000 and 2010, 103 and 108 patients were included, and the incidence of A. baumannii colonization/infection in the ICU decreased in 2010 (1.23 vs. 4.35 cases/1000 patient-days; pEnfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  11. Multilocus sequence typing of 125 carbapenem-resistant Acinetobacter baumannii isolates%125株耐碳青霉烯类抗菌药物鲍氏不动杆菌多位点序列分型

    Institute of Scientific and Technical Information of China (English)

    徐杰; 陈永德; 陈泽良; 刘世巍; 郭洁; 王丽丽; 王玉飞; 苑锡铜; 袁静; 宋宏彬; 黄留玉; 张宁

    2012-01-01

    目的 了解医院耐碳青霉烯类鲍氏不动杆菌的遗传特征.方法 选取耐碳青霉烯类鲍氏不动杆菌分离株,进行多位点序列分型(MLST).结果 选取的125株耐碳青霉烯类鲍氏不动杆菌,7个看家基因中6个等位基因数为1,gpi的等位基因数为3,可变位点数为3;125株菌MLST分析,3个ST型,其中ST 75型有82株,ST92型有20株,ST138型有23株,ST75、ST92与ST138属于同一克隆群.结论 医院耐碳青霉烯类鲍氏不动杆菌相对进化较慢,对多种抗菌药物耐药,应严格消毒措施及无菌操作,减少由耐碳青霉烯类鲍氏不动杆菌引起的医院感染;减少抗菌药物的使用,减缓泛耐药菌的产生.%OBJECTIVE To explore the genetic characteristics of carbapenem-resistant Acinetobacter baumannii isolated from the hospital. METHODS Carbapenem-resistant A. Baumannii isolates were selected for multilocus sequence typing (MLST). RESULTS Of the 125 carbapenem-resistant A. Baumannii isolates selected, the valuse of six alleles were 1 in the 7 housekeeping genes, and 3 in gpi gene alleles with 3 variable sites; The MLST analysis of carbapenem-resistant isolates showed that there were 3 types of ST, including ST75 in 82 strains, ST92 in 20 srtains, and ST138 in 23 strains. ST75, ST92, and ST138 belonged to the same clonal complex. CONCLUSION The evolution of carbapenem-resistant A. Baumannii isolates, which are resistant to most types of antibiotics, is relatively low; strict adherence to disinfection measures and the aseptic operation should be encouraged to control the nosocomial infections caused by carbapenem-resistant A. Baumannii isolates. Reduceing the use of the antibiotics may slow down the occurrence of resistant strains.

  12. 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.

  13. Diversity of multi-drug resistant Acinetobacter baumannii population in a major hospital in Kuwait

    Directory of Open Access Journals (Sweden)

    Leila eVali

    2015-07-01

    Full Text Available Acinetobacter baumannii is one of the most important opportunistic pathogens that causes serious health care associated complications in critically ill patients. In the current study we report on the diversity of the clinical multi-drug resistant A. baumannii in Kuwait by molecular characterization. One hundred A. baumannii were isolated from one of the largest governmental hospitals in Kuwait. Following the identification of the isolates by molecular methods, the amplified blaOXA-51-like gene product of one isolate (KO-12 recovered from blood showed the insertion of the ISAba19 at position 379 in blaOXA-78. Of the 33 multi-drug resistant isolates, 28 (85% contained blaOXA-23, 2 (6% blaOXA-24 and 6 (18% blaPER-1 gene. We did not detect blaOXA-58, blaVIM, blaIMP, blaGES, blaVEB and blaNDM genes in any of the tested isolates. In 3 blaPER-1 positive isolates the genetic environment of blaPER-1 consisted of two copies of ISPa12 (tnpiA1 surrounding the blaPER-1 gene on a highly stable plasmid of ca. 140-kb. MLST analysis of the 33 A. baumannii isolates identified 20 different STs, of which 6 (ST-607, ST-608, ST-609, ST-610, ST-611 and ST-612 were novel. Emerging STs such as ST15 (identified for the first time in the Middle East, ST78 and ST25 were also detected. The predominant clonal complex was CC2. PFGE and MLST defined the MDR isolates as multi-clonal with diverse lineages. Our results lead us to believe that A. baumannii is diverse in clonal origins and / or is undergoing clonal expansion continuously while multiple lineages of MDR A. baumannii circulate in hospital wards simultaneously.

  14. 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.

  15. Carbapenem-resistant Acinetobacter baumannii from Serbia: revision of CarO classification.

    Directory of Open Access Journals (Sweden)

    Katarina Novovic

    Full Text Available Carbapenem-resistant A. baumannii present a significant therapeutic challenge for the treatment of nosocomial infections in many European countries. Although it is known that the gradient of A. baumannii prevalence increases from northern to southern Europe, this study provides the first data from Serbia. Twenty-eight carbapenem-resistant A. baumannii clinical isolates were collected at a Serbian pediatric hospital during a 2-year period. The majority of isolates (67.68% belonged to the sequence type Group 1, European clonal complex II. All isolates harbored intrinsic OXA-51 and AmpC cephalosporinase. OXA-23 was detected in 16 isolates (57.14%, OXA-24 in 23 isolates (82.14% and OXA-58 in 11 isolates (39.29%. Six of the isolates (21.43% harbored all of the analyzed oxacillinases, except OXA-143 and OXA-235 that were not detected in this study. Production of oxacillinases was detected in different pulsotypes indicating the presence of horizontal gene transfer. NDM-1, VIM and IMP were not detected in analyzed clinical A. baumannii isolates. ISAba1 insertion sequence was present upstream of OXA-51 in one isolate, upstream of AmpC in 13 isolates and upstream of OXA-23 in 10 isolates. In silico analysis of carO sequences from analyzed A. baumannii isolates revealed the existence of two out of six highly polymorphic CarO variants. The phylogenetic analysis of CarO protein among Acinetobacter species revised the previous classification CarO variants into three groups based on strong bootstraps scores in the tree analysis. Group I comprises four variants (I-IV while Groups II and III contain only one variant each. One half of the Serbian clinical isolates belong to Group I variant I, while the other half belongs to Group I variant III.

  16. 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.

  17. 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

  18. 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

  19. The First Outbreak Caused by Acinetobacter baumannii ST208 and ST195 in China

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Transposons and integrons in colistin-resistant clones of Klebsiella pneumoniae and Acinetobacter baumannii with epidemic or sporadic behaviour.

    Science.gov (United States)

    Arduino, Sonia M; Quiroga, María Paula; Ramírez, María Soledad; Merkier, Andrea Karina; Errecalde, Laura; Di Martino, Ana; Smayevsky, Jorgelina; Kaufman, Sara; Centrón, Daniela

    2012-10-01

    Multiple transposons, integrons and carbapenemases were found in Klebsiella pneumoniae colistin-resistant isolates as well as a genomic resistance island of the AbaR type in Acinetobacter baumannii colistin-resistant isolates from different hospitals from Buenos Aires City. PFGE analysis showed a polyclonal dissemination of antimicrobial resistance mechanisms among K. pneumoniae isolates, while in A. baumannii isolates the epidemic clone 1 from South America was found. Resistance determinants associated with horizontal gene transfer are contributing to the evolution to pandrug resistance in both epidemic and sporadic clones.

  5. Genetic Mechanisms of Antimicrobial Resistance of Acinetobacter baumannii.

    Science.gov (United States)

    Esterly, John S; Richardson, Chad L; Eltoukhy, Noha S; Qi, Chao; Scheetz, Marc H

    2011-02-01

    To summarize published data identifying known genetic mechanisms of antibiotic resistance in Acinetobacter baumannii and the correlating phenotypic expression of antibiotic resistance. MEDLINE databases (1966-July 15, 2010) were searched to identify original reports of genetic mechanisms of antibiotic resistance in A. baumannii. Numerous genetic mechanisms of resistance to multiple classes of antibiotics are known to exist in A. baumannii, a gram-negative bacterium increasingly implicated in nosocomial infections. Mechanisms may be constitutive or acquired via plasmids, integrons, and transposons. Methods of resistance include enzymatic modification of antibiotic molecules, modification of antibiotic target sites, expression of efflux pumps, and downregulation of cell membrane porin channel expression. Resistance to β-lactams appears to be primarily caused by β-lactamase production, including extended spectrum β-lactamases (b/aTEM, blaSHV, b/aTX-M,b/aKPC), metallo-β-lactamases (blaMP, blaVIM, bla, SIM), and most commonly, oxacillinases (blaOXA). Antibiotic target site alterations confer resistance to fluoroquinolones (gyrA, parC) and aminoglycosides (arm, rmt), and to a much lesser extent, β-lactams. Efflux pumps (tet, ade, abe) contribute to resistance against β-lactams, tetracyclines, fluoroquinolones, and aminoglycosides. Finally, porin channel deletion (carO, oprD) appears to contribute to β-lactam resistance and may contribute to rarely seen polymyxin resistance. Of note, efflux pumps and porin deletions as solitary mechanisms may not render clinical resistance to A. baumannii. A. baumannii possesses copious genetic resistance mechanisms. Knowledge of local genotypes and expressed phenotypes for A. baumannii may aid clinicians more than phenotypic susceptibilities reported in large epidemiologic studies. © 2011 SAGE Publications.

  6. OXA- and GES-type β-lactamases predominate in extensively drug-resistant Acinetobacter baumannii isolates from a Turkish University Hospital.

    Science.gov (United States)

    Cicek, A C; Saral, A; Iraz, M; Ceylan, A; Duzgun, A O; Peleg, A Y; Sandalli, C

    2014-05-01

    We determined the antibiotic susceptibility and genetic mechanisms of resistance in clinical strains of Acinetobacter baumannii from Istanbul, Turkey. A total of 101 clinical strains were collected between November 2011 and July 2012. Antimicrobial susceptibility was performed using the Vitek 2 Compact system and E-test. Multiplex PCR was used for detecting bla(OXA -51-like), bla(OXA -23-like), bla(OXA -40-like) and bla(OXA -58-like) genes. ISAba1, bla(IMP -like), bla(VIM -like), bla(GES), bla(VEB), bla(PER -2), aac-3-Ia and aac-6'-Ib and NDM-1 genes were detected by PCR and sequencing. By multiplex PCR, all strains were positive for bla(OXA -51), 79 strains carried bla(OXA -23) and one strain carried bla(OXA -40). bla(OXA -51) and bla(OXA -23) were found together in 79 strains. ISAba1 element was detected in 81 strains, and in all cases it was found upstream of blaOXA -51 . GES-type carbapenemases were found in 24 strains (GES-11 in 16 strains and GES-22 in 8 strains) while bla(PER -2), bla(VEB -1), bla(NDM -1), blaIMP - and blaVIM -type carbapenemases were not observed. Aminoglycoside modifying enzyme (aac-3-Ia and aac-6'Ib) genes were detected in 13 and 15 strains, respectively. Ninety-seven (96%) A. baumannii strains were defined as MDR and of these, 98% were extensively drug resistant (sensitive only to colistin). Colistin remains the only active compound against all clinical strains. As seen in other regions, OXA-type carbapenemases, with or without an upstream ISAba1, predominate but GES-type carbapenemases also appear to have a significant presence. REP-PCR analysis was performed for molecular typing and all strains were collected into 12 different groups. To our knowledge, this is the first report of GES-11 and OXA-40 in A. baumannii from Turkey.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Rapid detection of Acinetobacter baumannii and molecular epidemiology of carbapenem-resistant A.baumannii in two comprehensive hospitals of Beijing, China

    Directory of Open Access Journals (Sweden)

    Puyuan eLi

    2015-09-01

    Full Text Available Acinetobacter baumannii is an important opportunistic pathogen associated with a variety of nosocomial infections. A rapid and sensitive molecular detection in clinical isolates is quite needed for the appropriate therapy and outbreak control of A. baumannii. Group 2 carbapenems have been considered the agents of choice for the treatment of multiple drug resistant A. baumannii. But the prevalence of carbapenem-resistant A. baumannii (CRAB has been steadily increasing in recent years. Here, we developed a loop-mediated isothermal amplification (LAMP assay for the rapid detection of A. baumannii in clinical samples by using high-specificity primers of the blaOXA-51 gene. Then we investigated the OXA-carbapenemases molecular epidemiology of A. baumannii isolates in 2 comprehensive hospitals in Beijing. The results showed that the LAMP assay could detect target DNA within 60 min at 65°C. The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR. Furthermore, this method could distinguish A. baumannii from the homologous A. nosocomialis and A. pittii. A total of 228 positive isolates were identified by this LAMP-based method for A. baumannii from 335 ICU patients with clinically suspected multi-resistant infections in 2 hospitals in Beijing. The rates of CRAB are on the rise and are slowly becoming a routine phenotype for A. baumannii. Among the CRABs, 92.3% harbored both the blaOXA-23 and blaOXA-51 genes. Thirty-three pulsotypes were identified by pulsed-field gel electrophoresis, and the majority belonged to clone C. In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research. We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.

  12. Effect of Chlorine Exposure on the Survival and Antibiotic Gene Expression of Multidrug Resistant Acinetobacter baumannii in Water

    Directory of Open Access Journals (Sweden)

    Deepti Prasad Karumathil

    2014-02-01

    Full Text Available Acinetobacter baumannii is a multidrug resistant pathogen capable of causing a wide spectrum of clinical conditions in humans. Acinetobacter spp. is ubiquitously found in different water sources. Chlorine being the most commonly used disinfectant in water, the study investigated the effect of chlorine on the survival of A. baumannii in water and transcription of genes conferring antibiotic resistance. Eight clinical isolates of A. baumannii, including a fatal meningitis isolate (ATCC 17978 (~108 CFU/mL were separately exposed to free chlorine concentrations (0.2, 1, 2, 3 and 4 ppm with a contact time of 30, 60, 90 and 120 second. The surviving pathogen counts at each specified contact time were determined using broth dilution assay. In addition, real-time quantitative PCR (RT-qPCR analysis of the antibiotic resistance genes (efflux pump genes and those encoding resistance to specific antibiotics of three selected A. baumannii strains following exposure to chlorine was performed. Results revealed that all eight A. baumannii isolates survived the tested chlorine levels during all exposure times (p > 0.05. Additionally, there was an up-regulation of all or some of the antibiotic resistance genes in A. baumannii, indicating a chlorine-associated induction of antibiotic resistance in the pathogen.

  13. 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

  14. 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.

  15. Synergistic effects of sulbactam in multi-drug-resistant Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    Fatih Temocin

    2015-12-01

    Full Text Available Abstract Acinetobacter baumannii is a frequently isolated etiologic agent of nosocomial infections, especially in intensive care units. With the increase in multi-drug resistance of A. baumannii isolates, finding appropriate treatment alternatives for infections caused by these bacteria has become more difficult, and available alternate treatments include the use of older antibiotics such as colistin or a combination of antibiotics. The current study aimed to evaluate the in vitro efficacy of various antibiotic combinations against multi-drug resistant A. baumannii strains. Thirty multi-drug and carbapenem resistant A. baumannii strains isolated at the Ankara Training and Research Hospital between June 2011 and June 2012 were used in the study. Antibiotic susceptibility tests and species-level identification were performed using conventional methods and the VITEK 2 system. The effects of meropenem, ciprofloxacin, amikacin, tigecycline, and colistin alone and in combination with sulbactam against the isolates were studied using Etest (bioMérieux in Mueller-Hinton agar medium. Fractional inhibitory concentration index (FIC was used to determine the efficacy of the various combinations. While all combinations showed a predominant indifferent effect, a synergistic effect was also observed in 4 of the 5 combinations. Synergy was demonstrated in 43% of the isolates with the meropenem-sulbactam combination, in 27% of the isolates with tigecycline-sulbactam, and in 17% of the isolates with colistin-sulbactam and amikacin-sulbactam. No synergy was detected with the sulbactam-ciprofloxacin combination and antagonism was detected only in the sulbactam-colistin combination (6.66% of the isolates. Antibiotic combinations can be used as an alternative treatment approach in multi-drug resistant A. baumannii infections.

  16. 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.

  17. 鲍氏不动杆菌临床分离株的耐药性变迁%Change of antimicrobial resistance of clinical isolates of Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    王军; 余清源; 刘华; 瞿秀

    2014-01-01

    目的:探讨2010-2012年山区医院临床分离的鲍氏不动杆菌(ABA )耐药性变迁,为临床选择抗菌药物提供实验室参考依据。方法对医院2010-2012年分离的353株ABA耐药性进行了回顾性调查分析;ABA分离培养严格按《全国临床检验操作规程》进行;采用法国生物梅里埃公司VITEK-32全自动微生物分析仪和配套鉴定试剂盒进行菌种鉴定;采用CLSI推荐的纸片扩散法(K-B法)进行药敏试验,并依据CLSI标准判读药敏结果,应用WHONET 5.5软件进行数据处理。结果医院ABA在呼吸道标本中检出率最高,占67.1%,其次是脓性分泌物和尿液,分别占11.1%和9.1%;ABA对临床常用抗菌药物的耐药性呈逐年升高趋势,对阿米卡星、亚胺培南、美罗培南、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦耐药率在12.6%~20.6%;2010-2012年泛耐药ABA检出率分别为12.6%、14.4%、16.3%;耐亚胺培南ABA检出率分别为14.9%、17.6%、17.7%。结论医院鲍氏不动杆菌的耐药性总体呈逐年上升态势,应严格执行卫生部《抗菌药物临床应用管理办法》,将ABA列入医院监控的重点菌株,实行医院细菌耐药性预警公示制度,扭转山区医院细菌耐药性上升的不良现状。%OBJECTIVE To approach the change of drug resistance of clinical isolates of A cinetobacter baumannii in mountain area so as to provide laboratory basis for clinical use of antibiotics .METHODS The drug resistance of 353 strains of A .baumannii isolated from 2010 to 2012 was retrospectively investigated ,then the isolation and culture of the A .baumannii strains were carried out by referring to National Guide to Clinical Laboratory Operation Proce-dures ,the strains were identified by using VITEK-32 automatic microorganism analyzer of BioMérieux ,France and matched identification detergent kit ,the drug susceptibility testing was

  18. 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.

  19. Anthelmintic closantel enhances bacterial killing of polymyxin B against multidrug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Tran, Thien B; Cheah, Soon-Ee; Yu, Heidi H; Bergen, Phillip J; Nation, Roger L; Creek, Darren J; Purcell, Anthony; Forrest, Alan; Doi, Yohei; Song, Jiangning; Velkov, Tony; Li, Jian

    2016-06-01

    Polymyxins, an old class of antibiotics, are currently used as the last resort for the treatment of multidrug-resistant (MDR) Acinetobacter baumannii. However, recent pharmacokinetic and pharmacodynamic data indicate that monotherapy can lead to the development of resistance. Novel approaches are urgently needed to preserve and improve the efficacy of this last-line class of antibiotics. This study examined the antimicrobial activity of novel combination of polymyxin B with anthelmintic closantel against A. baumannii. Closantel monotherapy (16 mg l(-1)) was ineffective against most tested A. baumannii isolates. However, closantel at 4-16 mg l(-1) with a clinically achievable concentration of polymyxin B (2 mg l(-1)) successfully inhibited the development of polymyxin resistance in polymyxin-susceptible isolates, and provided synergistic killing against polymyxin-resistant isolates (MIC ⩾4 mg l(-1)). Our findings suggest that the combination of polymyxin B with closantel could be potentially useful for the treatment of MDR, including polymyxin-resistant, A. baumannii infections. The repositioning of non-antibiotic drugs to treat bacterial infections may significantly expedite discovery of new treatment options for bacterial 'superbugs'.

  20. 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.

  1. Antibiotic resistance of acinetobacter baumannii isolated from 2007 to 2009:a dynamic analysis%2007-2009年鲍氏不动杆菌的耐药动态分析

    Institute of Scientific and Technical Information of China (English)

    王飞; 俞建; 严伟

    2011-01-01

    OBJECTIVE To monitor drug resistance of Acinetobacter baumannii in hospital from 2007 to 2009 in order to provide evidence to proper use antibacterial drug in clinics. METHODS A. baumannii isolates were collected from 2007 to 2009. Antibiotic susceptibility testing was performed by K-B method. RESULTS The isolating rate of A. baumannii from 2007 to 2009 was 4. 86%, 4. 98% and 5. 12%, respectively. There was a elevated tendency of the resistance rates to common antibacterials in A. baumannii during the past3a. The resistance rates of A. baumannii to cefoperazone-sulbactam and tobramycin were less than 50%, the others were more than 50. 00%. The increasing resistance rates of ceftriaxone, ciprofloxacin cefoperazone-sulbactam were very quickly. The resistance rates of antibacterials added β-lactamase inhibitors were lower than that without β-lactamase inhibitors. The sensitivity of A. baumannii to imipenem was decreased. CONCLUSION To prevent the A. baumannii infection outbreak, it is very important to monitor the drug sensitive test of bacteria and advocate the reasonable medication before beginning the treatment of infection caused by A. baumannii.%目的 监测医院临床标本鲍氏不动杆菌的耐药情况,指导临床合理用药. 方法 回顾性调查2007-2009年从患者不同标本分离的鲍氏不动杆菌,采用K-B纸片扩散法对常用的抗菌药物进行耐药动态分析. 结果 鲍氏不动杆菌3年检出率分别为4.86%、4.98%、5.12%;对常用抗菌药物的耐药率总体呈上升趋势,其中头孢哌酮/舒巴坦和妥布霉素的耐药率最低,3年来均保持<50.00%,其他药物的耐药率均有>50.00%的现象;头孢曲松、环丙沙星、头孢哌酮/舒巴坦的耐药率上升最快;加酶抑制剂的抗菌药物的耐药率相对较低;亚胺培南的敏感度已下降. 结论 动态监测鲍氏不动杆菌的耐药谱变化,及时调整治疗方案,有助于有效减少和控制鲍氏不动杆菌引起的医院感染.

  2. 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.

  3. Emergence of multidrug-resistant Acinetobacter baumannii producing OXA-23 Carbapenemase in Qatar

    Directory of Open Access Journals (Sweden)

    J.-M. Rolain

    2016-05-01

    Full Text Available The objective of our study was to describe the molecular support of carbapenem resistance from randomly selected clinical isolates of multidrug-resistant (MDR Acinetobacter baumannii as a pilot study from the Hamad Medical Corporation (HMC, Qatar. Results of our report will be used to study carbapenemases using molecular techniques in all isolated MDR A. baumannii. Forty-eight MDR A. baumannii were randomly selected from isolates preserved at HMC. Identification of all isolates was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic resistance was tested phenotypically by Phoenix and confirmed by Etest. The molecular support of carbapenemases (blaOXA-23, blaOXA-24, blaOXA-58, blaNDM was investigated by real-time PCR. The epidemiologic relatedness of the isolates was verified by phylogenetic analysis based on partial sequences of CsuE and blaOXA-51 genes. All 48 isolates were identified as A. baumannii and were confirmed to be resistant to most antibiotics, especially meropenem, imipenems, ciprofloxacin, levofloxacin, amikacin, gentamicin and most of the β-lactams; they were sensitive to colistin. All the isolates were positive for blaOXA-23 and negative for the other tested carbapenemase genes. Clonality analysis demonstrated that different lineages were actually circulating in Qatar; and we suggest that an outbreak occurred in the medical intensive care unit of HMC between 2011 and 2012. Here we report the emergence of MDR A. baumannii producing the carbapenemase OXA-23 in Qatar.

  4. The influence of carbapenem resistance on mortality in solid organ transplant recipients with Acinetobacter baumannii infection

    Directory of Open Access Journals (Sweden)

    de Gouvêa Erika

    2012-12-01

    Full Text Available Abstract Background Infection with carbapenem-resistant Acinetobacter baumannii has been associated with high morbidity and mortality in solid organ transplant recipients. The main objective of this study was to assess the influence of carbapenem resistance and other potential risk factors on the outcome of A. baumannii infection after kidney and liver transplantation. Methods Retrospective study of a case series of A. baumannii infection among liver and renal transplant recipients. The primary outcome was death associated with A. baumannii infection. Multivariate logistic regression was used to assess the influence of carbapenem resistance and other covariates on the outcome. Results Forty-nine cases of A. baumannii infection affecting 24 kidney and 25 liver transplant recipients were studied. Eighteen cases (37% were caused by carbapenem-resistant isolates. There were 17 (35% deaths associated with A. baumannii infection. In unadjusted analysis, liver transplantation (p = 0.003, acquisition in intensive care unit (p = 0.001, extra-urinary site of infection (p A. baumannii infection. The number of deaths associated with A. baumannii infection was higher among patients infected with carbapenem-resistant isolates, but the difference was not significant (p = 0.28. In multivariate analysis, the risk of A. baumannii-associated mortality was higher in patients with infection acquired in the intensive care unit (odds ratio [OR] = 34.8, p = 0.01 and on mechanical ventilation (OR = 15.2, p = 0.04. Appropriate empiric antimicrobial therapy was associated with significantly lower mortality (OR = 0.04, p = 0.03, but carbapenem resistance had no impact on it (OR = 0.73, p = 0.70. Conclusion These findings suggest that A. baumannii-associated mortality among liver and kidney transplant recipients is influenced by baseline clinical severity and by the early start of appropriate therapy, but not by carbapenem

  5. Repeated local emergence of carbapenem-resistant Acinetobacter baumannii in a single hospital ward

    Science.gov (United States)

    Pham Thanh, Duy; Tran Do Hoan, Nhu; Wick, Ryan R.; Ingle, Danielle J.; Hawkey, Jane; Edwards, David J.; Kenyon, Johanna J.; Phu Huong Lan, Nguyen; Campbell, James I.; Thwaites, Guy; Thi Khanh Nhu, Nguyen; Hall, Ruth M.; Fournier-Level, Alexandre; Baker, Stephen; Holt, Kathryn E.

    2016-01-01

    We recently reported a dramatic increase in the prevalence of carbapenem-resistant Acinetobacter baumannii infections in the intensive care unit (ICU) of a Vietnamese hospital. This upsurge was associated with a specific oxa23-positive clone that was identified by multilocus VNTR analysis. Here, we used whole-genome sequence analysis to dissect the emergence of carbapenem-resistant A. baumannii causing ventilator-associated pneumonia (VAP) in the ICU during 2009–2012. To provide historical context and distinguish microevolution from strain introduction, we compared these genomes with those of A. baumannii asymptomatic carriage and VAP isolates from this same ICU collected during 2003–2007. We identified diverse lineages co-circulating over many years. Carbapenem resistance was associated with the presence of oxa23, oxa40, oxa58 and ndm1 genes in multiple lineages. The majority of resistant isolates were oxa23-positive global clone GC2; fine-scale phylogenomic analysis revealed five distinct GC2 sublineages within the ICU that had evolved locally via independent chromosomal insertions of oxa23 transposons. The increase in infections caused by carbapenem-resistant A. baumannii was associated with transposon-mediated transmission of a carbapenemase gene, rather than clonal expansion or spread of a carbapenemase-harbouring plasmid. Additionally, we found evidence of homologous recombination creating diversity within the local GC2 population, including several events resulting in replacement of the capsule locus. We identified likely donors of the imported capsule locus sequences amongst the A. baumannii isolated on the same ward, suggesting that diversification was largely facilitated via reassortment and sharing of genetic material within the localized A. baumannii population.

  6. Clinical epidemiology and resistance mechanisms of carbapenem-resistant Acinetobacter baumannii, French Guiana, 2008-2014.

    Science.gov (United States)

    Mahamat, Aba; Bertrand, Xavier; Moreau, Brigitte; Hommel, Didier; Couppie, Pierre; Simonnet, Christine; Kallel, Hatem; Demar, Magalie; Djossou, Felix; Nacher, Mathieu

    2016-07-01

    This study investigated the clinical epidemiology and resistance mechanisms of Acinetobacter baumannii and characterised the clonal diversity of carbapenem-resistant A. baumannii (CRAB) during an ICU-associated outbreak at Cayenne Hospital, French Guiana. All non-duplicate A. baumannii isolates from 2008 to 2014 were tested for antibiotic susceptibility by disk diffusion. Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on CRAB. Of the 441 A. baumannii isolates, most were from males (54.0%) and were detected mainly from the ICU (30.8%) and medicine wards (21.8%). In the ICU, strains were mainly isolated from the respiratory tract (44.1%) and bloodstream (14.0%), whereas in medicine wards they mainly were from wound/drainage (36.5%) and bloodstream (25.0%). A. baumannii showed the greatest susceptibility to piperacillin/tazobactam (92.7%), imipenem (92.5%), colistin (95.6%) and amikacin (97.2%), being lower in the ICU and medicine wards compared with other wards. An outbreak of OXA-23-producing CRAB occurred in the 13-bed ICU in 2010. CRAB strains were more co-resistant to other antimicrobials compared with non-CRAB. Molecular genetics analysis revealed five sequence types [ST78, ST107 and ST642 and two new STs (ST830 and ST831)]. Analysis of PFGE profiles indicated cross-transmissions of CRAB within the ICU, between the ICU and one medicine ward during transfer of patients, and within that medicine ward. This study provides the first clinical and molecular data of A. baumannii from French Guiana and the Amazon basin. The ICU was the highest risk unit of this nosocomial outbreak of OXA-23-producing CRAB, which could subsequently disseminate within the hospital.

  7. Epidemiological and clinical features associated with colonisation/infection by Acinetobacter baumannii with phenotypic heterogeneous resistance to carbapenems.

    Science.gov (United States)

    Fernández-Cuenca, Felipe; Gómez-Sánchez, M; Rodríguez-Baño, Jesús; Martínez-Martínez, Luis; Vila, Jordi; Bou, Germán; Pascual, Alvaro

    2012-09-01

    The objective of this study was to identify risk factors for the acquisition of Acinetobacter baumannii with phenotypic heterogeneous resistance (PHR) to carbapenems and to determine whether these factors are similar to those associated with A. baumannii not showing this phenotype. Microbiological and clinical data from 211 patients included in the GEIH-Ab 2000 project were used. Isolates of A. baumannii were studied for their susceptibility to imipenem (IPM) by microdilution and for PHR to IPM as determined by the presence of colonies growing within the inhibition zone of IPM disks. Isolates were divided into three groups: (i) IPM-PHR isolates, i.e. susceptible and non-susceptible A. baumannii displaying PHR to IPM; (ii) non-IPM-PHR isolates, i.e. susceptible A. baumannii showing an inhibition halo but no colonies growing within it; and (iii) IPM-FR isolates, i.e. fully resistant A. baumannii displaying no halo of inhibition. IPM-PHR isolates of A. baumannii were more commonly isolated from respiratory tract samples and less commonly from urine, and were more frequently causes of infection than were IPM-FR isolates. Independent risk factors identified in patients with IPM-PHR isolates were Intensive Care Unit admission, surgery, and previous use of piperacillin/tazobactam or carbapenems, whilst risk factors for IPM-FR and IPM-PHR were previous use of cephalosporins and isolation from a urine sample. In conclusion, risk factors associated with colonisation/infection by isolates of A. baumannii with PHR to carbapenems are similar to those previously described for isolates resistant to carbapenems.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Early detection of metallo-β-lactamase NDM-1- and OXA-23 carbapenemase-producing Acinetobacter baumannii in Libyan hospitals.

    Science.gov (United States)

    Mathlouthi, Najla; El Salabi, Allaaeddin Ali; Ben Jomàa-Jemili, Mariem; Bakour, Sofiane; Al-Bayssari, Charbel; Zorgani, Abdulaziz A; Kraiema, Abdulmajeed; Elahmer, Omar; Okdah, Liliane; Rolain, Jean-Marc; Chouchani, Chedly

    2016-07-01

    Acinetobacter baumannii is an opportunistic pathogen causing various nosocomial infections. The aim of this study was to characterise the molecular support of carbapenem-resistant A. baumannii clinical isolates recovered from two Libyan hospitals. Bacterial isolates were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antibiotic susceptibility testing was performed using disk diffusion and Etest methods, and carbapenem resistance determinants were studied by PCR amplification and sequencing. Multilocus sequence typing (MLST) was performed for typing of the isolates. All 36 imipenem-resistant isolates tested were identified as A. baumannii. The blaOXA-23 gene was detected in 29 strains (80.6%). The metallo-β-lactamase blaNDM-1 gene was detected in eight isolates (22.2%), showing dissemination of multidrug-resistant (MDR) A. baumannii in Tripoli Medical Center and Burn and Plastic Surgery Hospital in Libya, including one isolate that co-expressed the blaOXA-23 gene. MLST revealed several sequence types (STs). Imipenem-resistant A. baumannii ST2 was the predominant clone (16/36; 44.4%). This study shows that NDM-1 and OXA-23 contribute to antibiotic resistance in Libyan hospitals and represents the first incidence of the association of these two carbapenemases in an autochthonous MDR A. baumannii isolated from patients in Libya, indicating that there is a longstanding infection control problem in these hospitals.

  13. Differential Role of the T6SS in Acinetobacter baumannii Virulence.

    Directory of Open Access Journals (Sweden)

    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.

  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. Changes in resistance percentage to antibiotics in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from blood cultures of intensive care unit patients

    Directory of Open Access Journals (Sweden)

    Berrin Uzun

    2014-05-01

    was found in resistance percentage of cefepime and amikacin in the second period compared with the first (p values were 0.0003, 0.0000. Resistance percentage of ampicillin-sulbactam, piperacillin-tazobactam and imipenem was increased (p values were 0.0003, 0.0210, 0.0033. There was no colistin resistance determined in both species. Tigecycline resistance was not found in A. baumannii isolates.[¤]CONCLUSION[|]Active surveillance of antibiotic resistance percentages of isolated strains especially in ICUs serves to determine empirical treatment regimens in every institution. The present study emphasized that antibiotic usage policy is an important step to combat hospital infections. Consequently, infection control measures should be taken, empirical treatment regimens should be constantly reviewed, and should be determined according to active surveillance data in order to decrease resistance percentages.[¤

  16. Outbreak of resistant Acinetobacter baumannii: measures and proposal for prevention and control

    Directory of Open Access Journals (Sweden)

    Roberta Maia de Castro Romanelli

    2009-10-01

    Full Text Available Acinetobacter baumannii colonization and infection, frequent in Intensive Care Unit (ICU patients, is commonly associated with high morbimortality. Several outbreaks due to multidrug-resistant (MDR A. baumanii have been reported but few of them in Brazil. This study aimed to identify risk factors associated with colonization and infection by MDR and carbapenem-resistant A. baumannii strains isolated from patients admitted to the adult ICU at HC/UFMG. A case-control study was performed from January 2007 to June 2008. Cases were defined as patients colonized or infected by MDR/carbapenem-resistant A. baumannii, and controls were patients without MDR/carbapenem-resistant A. baumannii isolation, in a 1:2 proportion. For statistical analysis, due to changes in infection control guidelines, infection criteria and the notification process, this study was divided into two periods. During the first period analyzed, from January to December 2007, colonization or infection by MDR/carbapenem-resistant A. baumannii was associated with prior infection, invasive device utilization, prior carbapenem use and clinical severity. In the multivariate analysis, prior infection and mechanical ventilation proved to be statistically significant risk factors. Carbapenem use showed a tendency towards a statistical association. During the second study period, from January to June 2008, variables with a significant association with MDR/carbapenem-resistant A. baumannii colonization/infection were catheter utilization, carbapenem and third-generation cephalosporin use, hepatic transplantation, and clinical severity. In the multivariate analysis, only CVC use showed a statistical difference. Carbapenem and third-generation cephalosporin use displayed a tendency to be risk factors. Risk factors must be focused on infection control and prevention measures considering A. baumanni dissemination.

  17. Predictors of mortality in patients with extensively drug-resistant Acinetobacter baumannii pneumonia receiving colistin therapy.

    Science.gov (United States)

    Choi, Ik Sung; Lee, Yu Ji; Wi, Yu Mi; Kwan, Byung Soo; Jung, Kae Hwa; Hong, Woong Pyo; Kim, June Myong

    2016-08-01

    The ratio of the area under the free (unbound) concentration-time curve to minimum inhibitory concentration (fAUC/MIC) was proposed to be the pharmacokinetic/pharmacodynamic index most strongly linked to the antibacterial effect of colistin against Acinetobacter baumannii. A retrospective study of patients who received colistin to treat pneumonia caused by extensively drug-resistant (XDR) A. baumannii over a 4-year period was performed to assess the impact of the colistin MIC on mortality. A total of 227 patients were included in the analysis. The 7-day and 14-day mortality rates of patients with XDR A. baumannii pneumonia receiving colistin therapy were 15.0% and 23.8%, respectively. In the multivariate analysis, Acute Physiology and Chronic Health Evaluation (APACHE) II score, days from index culture to first dose of colistin, underlying tumour and septic shock at presentation were independent predictors of mortality in patients with XDR A. baumannii pneumonia receiving colistin therapy. In the univariate analysis, the colistin dose based on ideal body weight (IBW) correlated with patient outcome. Therefore, the use of IBW appeared to be more appropriate to calculate the colistin dosage. In addition, these results highlight the clinical significance of colistin MIC in patients with XDR A. baumannii pneumonia receiving colistin therapy. Although MICs were in the 'susceptible' range, patients infected with isolates with high colistin MICs showed a poorer clinical response rate than patients infected with isolates with low colistin MICs. Further clinical studies are needed to evaluate the roles of colistin MIC for predicting mortality in XDR A. baumannii pneumonia with a high colistin MIC.

  18. Outbreak of resistant Acinetobacter baumannii- measures and proposal for prevention and control.

    Science.gov (United States)

    Romanelli, Roberta Maia de Castro; Jesus, Lenize Adriana de; Clemente, Wanessa Trindade; Lima, Stella Sala Soares; Rezende, Edna Maria; Coutinho, Rosane Luiza; Moreira, Ricardo Luiz Fontes; Neves, Francelli Aparecida Cordeiro; Brás, Nelma de Jesus

    2009-10-01

    Acinetobacter baumannii colonization and infection, frequent in Intensive Care Unit (ICU) patients, is commonly associated with high morbimortality. Several outbreaks due to multidrug-resistant (MDR) A. baumanii have been reported but few of them in Brazil. This study aimed to identify risk factors associated with colonization and infection by MDR and carbapenem-resistant A. baumannii strains isolated from patients admitted to the adult ICU at HC/UFMG. A case-control study was performed from January 2007 to June 2008. Cases were defined as patients colonized or infected by MDR/carbapenem-resistant A. baumannii, and controls were patients without MDR/carbapenem-resistant A. baumannii isolation, in a 1:2 proportion. For statistical analysis, due to changes in infection control guidelines, infection criteria and the notification process, this study was divided into two periods. During the first period analyzed, from January to December 2007, colonization or infection by MDR/carbapenem-resistant A. baumannii was associated with prior infection, invasive device utilization, prior carbapenem use and clinical severity. In the multivariate analysis, prior infection and mechanical ventilation proved to be statistically significant risk factors. Carbapenem use showed a tendency towards a statistical association. During the second study period, from January to June 2008, variables with a significant association with MDR/carbapenem-resistant A. baumannii colonization/infection were catheter utilization, carbapenem and third-generation cephalosporin use, hepatic transplantation, and clinical severity. In the multivariate analysis, only CVC use showed a statistical difference. Carbapenem and third-generation cephalosporin use displayed a tendency to be risk factors. Risk factors must be focused on infection control and prevention measures considering A. baumanni dissemination.

  19. Repurposing the anticancer drug mitomycin C for the treatment of persistent Acinetobacter baumannii infections.

    Science.gov (United States)

    Cruz-Muñiz, Martha Yumiko; López-Jacome, Luis Esau; Hernández-Durán, Melissa; Franco-Cendejas, Rafael; Licona-Limón, Paula; Ramos-Balderas, Jose Luis; Martinéz-Vázquez, Mariano; Belmont-Díaz, Javier A; Wood, Thomas K; García-Contreras, Rodolfo

    2017-01-01

    Acinetobacter baumannii is an emergent opportunistic bacterial pathogen responsible for recalcitrant infections owing to its high intrinsic tolerance to most antibiotics; therefore, suitable strategies to treat these infections are needed. One plausible approach is the repurposing of drugs that are already in use. Among them, anticancer drugs may be especially useful due their cytotoxic activities and ample similarities between bacterial infections and growing tumours. In this work, the effectiveness of four anticancer drugs on the growth of A. baumannii ATTC BAA-747 was evaluated, including the antimetabolite 5-fluorouracil and three DNA crosslinkers, namely cisplatin, mitomycin C (MMC) and merphalan. MMC was the most effective drug, having a minimum inhibitory concentration for 50% of growth in Luria-Bertani medium at ca. 7 µg/mL and completely inhibiting growth at 25 µg/mL. Hence, MMC was tested against a panel of 21 clinical isolates, including 18 multidrug-resistant (MDR) isolates, 3 of which were sensitive only to colistin. The minimum inhibitory concentrations and minimum bactericidal concentrations of MMC in all tested strains were found to be similar to those of A. baumannii ATCC BAA-747, and MMC also effectively killed stationary-phase, persister and biofilm cells. Moreover, MMC was able to increase survival of the insect larvae Galleria mellonella against an otherwise lethal A. baumannii infection from 0% to ≥53% for the antibiotic-sensitive A. baumannii ATCC BAA-747 strain and the MDR strains A560 and A578. Therefore, MMC is highly effective at killing the emergent opportunistic pathogen A. baumannii.

  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. Clinical distribution and drug-resistance analysis of Acinetobacter baumannii isolated from our hospital in 2014%某院2014年鲍曼不动杆菌感染的临床分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    周廷栋; 刘周; 管世鹤

    2016-01-01

    Objective To analyze the clinical characteristics of acinetobacter baumannii infection and drug resistance tendency of our hospital in 2014 ,so as to promote the clinical rational use of antibiotics .Methods The study was a retrospective review ,the re‐sults of clinical distribution and drug resistance of acinetobacter baumannii isolated from our hospital in 2014 were analyzed .The an‐timicrobial susceptibility testing(AST) of acinetobacter baumannii was determined by K‐B disk diffusion method and minimal inhib‐itory concentration(MIC) test ,respectively .The AST was performed as recommended by CLSI 2010 .Results A total of 299 strains of acinetobacter baumannii were isolated from clinical specimens throughout the year .Of the 299 Acinetobacter baumannii isolates , 268 strains(89 .63% ) were isolated from sputum ,165 strains(55 .18% ) of Acinetobacter baumannii were from intensive care unit (ICU) and 52 strains(17 .39% ) were from neurosurgery .The resistance rate of Acinetobacter baumannii to cefoperazone/sulbactam was 5 .02% while its resistance to Imipenem and Meropenem significantly increased to 52 .17% and 56 .86% ,respectively .And the resistance rates ofβ‐lactams ,fluoroquinolones and aminoglycosides were higher than 60% .Conclusion The isolation rate of Acine‐tobacter baumannii is increasing in recent year in our hospital ,as well the resistance rate to the common Antibiotics .Monitoring the resistance of Acinetobacter baumannii should be strengthened for preventing resistant bacteria from spreading .%目的:分析该院2014年鲍曼不动杆菌感染的临床特点及耐药趋势,从而促进临床合理使用抗菌药物。方法对2014年该院临床标本中分离的鲍曼不动杆菌进行回顾性分析。应用MicroScan WalkAway‐40SI的NC31板对分离出的细菌进行鉴定,并以M IC法及K‐B法进行药物敏感试验,按CLSI 2010年版标准对药敏结果进行判断。结果全年共分离鉴定鲍曼不动杆菌299

  2. 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.

  3. 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.

  4. 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.

  5. Isolation and antimicrobial resistance of imipenem/cilastatin-resistant Acinetobacter baumannii%耐亚胺培南/西司他丁鲍曼不动杆菌的分离及耐药性

    Institute of Scientific and Technical Information of China (English)

    欧阳育琪; 史文元; 黄红卫; 林应标; 黄强; 熊劲芝

    2011-01-01

    Objective To study the isolation and antimicrobial resistance of imipenem/cilastatin (IPM)-resistant Acinetobacter baumannii (A. Baumannii) in a hospital. Methods Clinical specimens were collected from January 2006 to December 2010, except the blood culture was performed with United States BD BACTEC9120 system, the other specimens were cultured and isolated bacteria with routine method ; strains were identified and performed drug sensitive test with Phoenix 100 automatic analysis system and reagents. The metallo-j3-lactamases were detected with 2-mercaptopropanoic acid inhibited assays. Results One hundred and fifty-four (74. 03%) IPM-resistant A. Baumannii strains were mainly isolated from sputum and throat swabs, strains mainly distributed in the following departments: intensive care unit (98 isolates,63. 64%),. Department of neurology (25,16. 23%), burn unit (13, 8.44%), respiratory department(8, 5. 19%), geriatrics department (4, 2. 60%), department of general surgery (3,1. 95%), and hematological department(3,1. 95%) . IPM-resistant A. Baumannii had the lowest resistant rate to cefoperazone/sulbactam (42. 21%), and the resistant rates to the other antimicrobial agents were all >65 %. The rate of metallo-fMactamase-producing strains was 14. 94%(23/154). Conclusion The IPM-resistant A. Baumannii are chiefly from specimens in respiratory tract infection, and the susceptibility to antimicrobial agents is low. The strengthening of the monitor and optimization use of antimicrobial agents is important for controlling the prevalence of IPM-resistant A. Baumannii in hospitals.%目的 了解耐亚胺培南/西司他丁(IPM)鲍曼不动杆菌(Ab)在某院的分离及其耐药性.方法 收集该院2006年1月-2010年12月临床各类标本,除血培养采用美国BD公司BACTEC9120进行检测,其余标本按常规方法培养分离细菌;在Phoenix 100全自动分析系统和配套试剂中,对菌株进行鉴定及药敏试验.采用2-巯基丙酸抑

  6. Development of TaqMan real-time polymerase chain reaction for the detection of the newly emerging form of carbapenem resistance gene in clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    V Manchanda

    2011-01-01

    Full Text Available Purpose: The newly emerging form of the so-called New Delhi Metallo-beta-lactamases (NDM-1 has been reported recently from patients worldwide and broadly thought as a potential source for the major global health problem. Thus, it is important to study the epidemiology of the so-called NDM-1 harbouring bacteria to prevent its further spread and to place effective control measures. The present study describes the use of the real-time polymerase chain reaction (PCR assay for the detection of the bla NDM-1 gene using TaqMan probes among clinical isolates. Materials and Methods: Clinical isolates of Escherichia coli (11 strains, Klebsiella pneumoniae (17 strains and Acinetobacter baumannii (six strains that were resistant to either of the carbapenems (meropenem or imipenem were included in the study. The presence of carbapenemases in such strains was confirmed using the modified Hodge test. A real-time PCR assay was optimized for the detection of NDM-1 using a cloned synthetic gene fragment followed by testing of the clinical isolates. The findings were further confirmed using PCR and gene sequencing. Results: TaqMan probe assay displayed a good detection limit with analytical sensitivity of the assay up to 10 copies of bla NDM-1 gene per reaction. The isolates of E. coli and K. pneumoniae revealed narrow range crossing point values (Cp values between (12-17 cycles (mean Cp value 14, indicating number of bla NDM-1 gene copies of 106-108. The wider range of Cp values (15-34 cycles with a higher mean Cp value (23.6 was observed in A. baumannii with number of bla NDM-1 gene copies of 103-108. Conclusions: The study demonstrates that real-time PCR assay based on TaqMan chemistry is a useful technique for the detection of bla NDM-1 harbouring clinical isolates of E. coli, K. pneumoniae and A. baumannii. The assay has great precision in measuring the number of bla NDM-1 gene copies per specimen of DNA.

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

    Directory of Open Access Journals (Sweden)

    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. 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. Small, Enigmatic Plasmids of the Nosocomial Pathogen, Acinetobacter baumannii: Good, Bad, Who Knows?

    Directory of Open Access Journals (Sweden)

    Soo Sum Lean

    2017-08-01

    Full Text Available Acinetobacter baumannii is a Gram-negative nosocomial pathogen that has become a serious healthcare concern within a span of two decades due to its ability to rapidly acquire resistance to all classes of antimicrobial compounds. One of the key features of the A. baumannii genome is an open pan genome with a plethora of plasmids, transposons, integrons, and genomic islands, all of which play important roles in the evolution and success of this clinical pathogen, particularly in the acquisition of multidrug resistance determinants. An interesting genetic feature seen in majority of A. baumannii genomes analyzed is the presence of small plasmids that usually ranged from 2 to 10 kb in size, some of which harbor antibiotic resistance genes and homologs of plasmid mobilization genes. These plasmids are often overlooked when compared to their larger, conjugative counterparts that harbor multiple antibiotic resistance genes and transposable elements. In this mini-review, we will examine our current knowledge of these small A. baumannii plasmids and look into their genetic diversity and phylogenetic relationships. Some of these plasmids, such as the Rep-3 superfamily group and the pRAY-type, which has no recognizable replicase genes, are quite widespread among diverse A. baumannii clinical isolates worldwide, hinting at their usefulness to the lifestyle of this pathogen. Other small plasmids especially those from the Rep-1 superfamily are truly enigmatic, encoding only hypothetical proteins of unknown function, leading to the question of whether these small plasmids are “good” or “bad” to their host A. baumannii.

  10. Iron-Regulated Phospholipase C Activity Contributes to the Cytolytic Activity and Virulence of Acinetobacter baumannii

    Science.gov (United States)

    Fiester, Steven E.; Schmidt, Robert E.; Beckett, Amber C.; Ticak, Tomislav; Carrier, Mary V.; Ghosh, Rajarshi; Ohneck, Emily J.; Metz, Maeva L.; Sellin Jeffries, Marlo K.; Actis, Luis A.

    2016-01-01

    Acinetobacter baumannii is an opportunistic Gram-negative pathogen that causes a wide range of infections including pneumonia, septicemia, necrotizing fasciitis and severe wound and urinary tract infections. Analysis of A. baumannii representative strains grown in Chelex 100-treated medium for hemolytic activity demonstrated that this pathogen is increasingly hemolytic to sheep, human and horse erythrocytes, which interestingly contain increasing amounts of phosphatidylcholine in their membranes. Bioinformatic, genetic and functional analyses of 19 A. baumannii isolates showed that the genomes of each strain contained two phosphatidylcholine-specific phospholipase C (PC-PLC) genes, which were named plc1 and plc2. Accordingly, all of these strains were significantly hemolytic to horse erythrocytes and their culture supernatants tested positive for PC-PLC activity. Further analyses showed that the transcriptional expression of plc1 and plc2 and the production of phospholipase and thus hemolytic activity increased when bacteria were cultured under iron-chelation as compared to iron-rich conditions. Testing of the A. baumannii ATCC 19606T plc1::aph-FRT and plc2::aph isogenic insertion derivatives showed that these mutants had a significantly reduced PC-PLC activity as compared to the parental strain, while testing of plc1::ermAM/plc2::aph demonstrated that this double PC-PLC isogenic mutant expressed significantly reduced cytolytic and hemolytic activity. Interestingly, only plc1 was shown to contribute significantly to A. baumannii virulence using the Galleria mellonella infection model. Taken together, our data demonstrate that both PLC1 and PLC2, which have diverged from a common ancestor, play a concerted role in hemolytic and cytolytic activities; although PLC1 seems to play a more critical role in the virulence of A. baumannii when tested in an invertebrate model. These activities would provide access to intracellular iron stores this pathogen could use during

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. Immunization against multidrug-resistant Acinetobacter baumannii effectively protects mice in both pneumonia and sepsis models.

    Directory of Open Access Journals (Sweden)

    Weiwei Huang

    Full Text Available OBJECTIVE: Acinetobacter baumannii is considered the prototypical example of a multi- or pan- drug-resistant bacterium. It has been increasingly implicated as a major cause of nosocomial and community-associated infections. This study proposed to evaluate the efficacy of immunological approaches to prevent and treat A. baumannii infections. METHODS: Mice were immunized with outer membrane vesicles (OMVs prepared from a clinically isolated multidrug-resistant strain of A. baumannii. Pneumonia and sepsis models were used to evaluate the efficacy of active and passive immunization with OMVs. The probable effective mechanisms and the protective potential of clonally distinct clinical isolates were investigated in vitro using an opsonophagocytic assay. RESULTS: Intramuscular immunization with OMVs rapidly produced high levels of OMV-specific IgG antibodies, and subsequent intranasal challenge with A. baumannii elicited mucosal IgA and IgG responses. Both active and passive immunization protected the mice from challenges with homologue bacteria in a sepsis model. Bacterial burden in bronchoalveolar lavage fluids (BALF, lung, and spleen, inflammatory cell infiltration in BALF and lung, and inflammatory cytokine accumulation in BALF was significantly suppressed in the pneumonia model by both active and passive immunization strategies. The antisera from immunized mice presented with significant opsonophagocytic activities in a dose-dependent manner against not only homologous strains but also five of the other six clonally distinct clinical isolates. CONCLUSIONS: Utilizing immunological characteristics of outer membrane proteins to elevate protective immunity and circumvent complex multidrug-resistance mechanisms might be a viable approach to effectively control A. baumannii infections.

  16. Analysis on the drug resistance and the distribution of clinical isolated Acinetobacter baumannii in a hospital from 2012 to 2014%2012至2014年某院临床分离的鲍曼不动杆菌的耐药性及分布

    Institute of Scientific and Technical Information of China (English)

    刘静; 姜梅杰; 王桂明

    2015-01-01

    目的:动态监测院内分离的鲍曼不动杆菌对临床常用抗菌药物耐药率的变化及分布,为院内感染控制提供理论依据。方法用WHONET 5.6对2012年1月至2014年12月山东省泰安市中心医院临床分离的鲍曼不动杆菌对亚胺培南等13种抗菌药物的耐药性及分布进行分析。结果2012年分离的616株鲍曼不动杆菌对亚胺培南等13种抗菌药物的耐药率(52.9%~94.0%)高于2013年分离的536株鲍曼不动杆菌对亚胺培南等13种抗菌药物的耐药率(37.7%~70.1%)。2014年分离的421株鲍曼不动杆菌对左旋氧氟沙星和妥布霉素的耐药率高于2013年分离的鲍曼不动杆菌对左旋氧氟沙星和妥布霉素的耐药率,但2014年分离的鲍曼不动杆菌对其余11种抗菌药物的耐药率(37.2%~65.6%)低于2013年分离的鲍曼不动杆菌的耐药率。院内3年间分离的鲍曼不动杆菌88.4%~92.5%的标本来源于痰液。结论3年间本院临床分离的鲍曼不动杆菌对多数常用抗菌药物的耐药率逐年下降。加强对多重耐药鲍曼不动杆菌的感染控制,可预防和减少院内多重耐药鲍曼不动杆菌的产生和传播。%Objective To monitoring dynamicly the distribution and drug resistances of clinical isolated Acinetobacter baumannii to the common antimicrobial, and to provide theoretical basis for nosocomial infection control. Methods The distribution and drug resistances of clinical isolated Acinetobacter baumannii collected from January 2012 to December 2014 to 13 antibacterial including imipenem were analyzed by WHONET 5.6, retrospectively. Results The drug resistances rates (52.9%-94.0%) of 616 strains Acinetobacter baumannii isolates collected during 2012 to 13 antibacterial were higher than the drug resistances of 536 strains Acinetobacter baumannii collected during 2013 (37.7%-70.1%). The drug resistances rates of 421 strains Acinetobacter baumannii isolates collected during 2014 to

  17. 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.

  18. 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

  19. 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

  20. 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

    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

  1. 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...

  2. 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....

  3. CRISPR-cas subtype I-Fb in Acinetobacter baumannii: evolution and utilization for strain subtyping.

    Science.gov (United States)

    Karah, Nabil; Samuelsen, Ørjan; Zarrilli, Raffaele; Sahl, Jason W; Wai, Sun Nyunt; Uhlin, Bernt Eric

    2015-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are polymorphic elements found in the genome of some or all strains of particular bacterial species, providing them with a system of acquired immunity against invading bacteriophages and plasmids. Two CRISPR-Cas systems have been identified in Acinetobacter baumannii, an opportunistic pathogen with a remarkable capacity for clonal dissemination. In this study, we investigated the mode of evolution and diversity of spacers of the CRISPR-cas subtype I-Fb locus in a global collection of 76 isolates of A. baumannii obtained from 14 countries and 4 continents. The locus has basically evolved from a common ancestor following two main lineages and several pathways of vertical descent. However, this vertical passage has been interrupted by occasional events of horizontal transfer of the whole locus between distinct isolates. The isolates were assigned into 40 CRISPR-based sequence types (CST). CST1 and CST23-24 comprised 18 and 9 isolates, representing two main sub-clones of international clones CC1 and CC25, respectively. Epidemiological data showed that some of the CST1 isolates were acquired or imported from Iraq, where it has probably been endemic for more than one decade and occasionally been able to spread to USA, Canada, and Europe. CST23-24 has shown a remarkable ability to cause national outbreaks of infections in Sweden, Argentina, UAE, and USA. The three isolates of CST19 were independently imported from Thailand to Sweden and Norway, raising a concern about the prevalence of CST19 in Thailand. Our study highlights the dynamic nature of the CRISPR-cas subtype I-Fb locus in A. baumannii, and demonstrates the possibility of using a CRISPR-based approach for subtyping a significant part of the global population of A. baumannii.

  4. CRISPR-cas subtype I-Fb in Acinetobacter baumannii: evolution and utilization for strain subtyping.

    Directory of Open Access Journals (Sweden)

    Nabil Karah

    Full Text Available Clustered regularly interspaced short palindromic repeats (CRISPR are polymorphic elements found in the genome of some or all strains of particular bacterial species, providing them with a system of acquired immunity against invading bacteriophages and plasmids. Two CRISPR-Cas systems have been identified in Acinetobacter baumannii, an opportunistic pathogen with a remarkable capacity for clonal dissemination. In this study, we investigated the mode of evolution and diversity of spacers of the CRISPR-cas subtype I-Fb locus in a global collection of 76 isolates of A. baumannii obtained from 14 countries and 4 continents. The locus has basically evolved from a common ancestor following two main lineages and several pathways of vertical descent. However, this vertical passage has been interrupted by occasional events of horizontal transfer of the whole locus between distinct isolates. The isolates were assigned into 40 CRISPR-based sequence types (CST. CST1 and CST23-24 comprised 18 and 9 isolates, representing two main sub-clones of international clones CC1 and CC25, respectively. Epidemiological data showed that some of the CST1 isolates were acquired or imported from Iraq, where it has probably been endemic for more than one decade and occasionally been able to spread to USA, Canada, and Europe. CST23-24 has shown a remarkable ability to cause national outbreaks of infections in Sweden, Argentina, UAE, and USA. The three isolates of CST19 were independently imported from Thailand to Sweden and Norway, raising a concern about the prevalence of CST19 in Thailand. Our study highlights the dynamic nature of the CRISPR-cas subtype I-Fb locus in A. baumannii, and demonstrates the possibility of using a CRISPR-based approach for subtyping a significant part of the global population of A. baumannii.

  5. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii?

    Science.gov (United States)

    Ho, Chester H; Johnson, Tova; Miklacic, Joan; Donskey, Curtis J

    2009-10-01

    Ho CH, Johnson T, Miklacic J, Donskey CJ. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii? To determine the extent of environmental contamination associated with low-pressure pulsatile lavage of stage III or IV pressure ulcers in patients with spinal cord injury (SCI) when routine infection control precautions are used for wounds colonized or infected with Acinetobacter baumannii. Prospective investigation in which pressure ulcer cultures and environmental cultures were obtained before and after low-pressure pulsatile lavage treatment, and before and after regular dressing changes. Environmental cultures included the patient's bedrail and settle plates placed 0.6, 1.5, and 2.4m from the wound to assess airborne spread of A. baumannii. SCI inpatient unit in a Department of Veterans Affairs Medical Center. Inpatients (N=15) with SCI receiving daily low-pressure pulsatile lavage treatment for stage III or IV pressure ulcers with standard dressing change, as well as regular dressing changes without low-pressure pulsatile lavage at other times of the day. Standard, regular dressing changes and dressing changes with low-pressure pulsatile lavage. Comparison of frequency of environmental contamination with A. baumannii associated with low-pressure pulsatile lavage versus regular dressing changes. Of the 15 SCI inpatients meeting inclusion criteria, 9 (60%) grew A. baumannii from their wounds. Of the 9 patients with wound cultures positive for A. baumannii, only 1 (11%) had environmental contamination with this organism after performance of low-pressure pulsatile lavage, and the same patient had environmental contamination after a standard dressing change. The antibiotic susceptibility patterns of the wound and environmental A. baumannii isolates were identical. Low-pressure pulsatile lavage using the infection control methods described is not associated with an increased

  6. 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.

  7. 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.

  8. 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.

  9. Rapid and sensitive detection of carbapenemase activity in Acinetobacter baumannii using superficially porous liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lin, Huei-Ru; Hu, Anren; Lai, Meng-Jiun; Chiang, Chih-Wei; Liao, Chao-Chuan; Chang, Kai-Chih

    2016-12-01

    The emergence and spread of carbapenem-resistant Acinetobacter baumannii poses a challenge for optimizing antibiotic therapies and preventing outbreaks. Traditional phenotypic assays such as the modified Hodge test (MHT) or polymerase chain reaction (PCR)-based detection of the carbapenemase genes are time-consuming and complicated. Therefore, new approaches for the efficient detection of carbapenemase-producing A. baumannii are urgently required. In this study, we used the superficially porous liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to measure carbapenem hydrolysis in a solution spiked with test strains of A. baumannii. The rate of carbapenem hydrolysis during incubation was expressed as the ratio of the carbapenem peak area of the test A. baumannii strains to the noncarbapenemase-producing A. baumannii ATCC 17978. This method can accurately measure the carbapenem hydrolysis rate and, therefore, can effectively identify carbapenemase-producing strains within 75 minutes. A total of 112 A. baumannii strains were used in this study, including 103 clinical isolates with 68 carbapenem-resistant strains and 35 carbapenem-susceptible strains, seven ATCC strains and two selected mutants. The results of the superficially porous LC-MS/MS assay showed higher detection sensitivity compared to the results of the MHT. Our results demonstrate the ability of the former method to routinely detect carbapenemase-producing A. baumannii. Copyright © 2015. Published by Elsevier B.V.

  10. 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.

  11. Pharmacokinetics and Pharmacodynamics of Minocycline against Acinetobacter baumannii in a Neutropenic Murine Pneumonia Model.

    Science.gov (United States)

    Zhou, Jian; Ledesma, Kimberly R; Chang, Kai-Tai; Abodakpi, Henrietta; Gao, Song; Tam, Vincent H

    2017-05-01

    Multidrug-resistant (MDR) Acinetobacter baumannii is increasingly more prevalent in nosocomial infections. Although in vitro susceptibility of A. baumannii to minocycline is promising, the in vivo efficacy of minocycline has not been well established. In this study, the in vivo activity of minocycline was evaluated in a neutropenic murine pneumonia model. Specifically, we investigated the relationship between minocycline exposure and bactericidal activity using five A. baumannii isolates with a broad range of susceptibility (MIC ranged from 0.25 mg/liter to 16 mg/liter). The pharmacokinetics of minocycline (single dose of 25 mg/kg of body weight, 50 mg/kg, 100 mg/kg, and a humanized regimen, given intraperitoneally) in serum and epithelial lining fluid (ELF) were characterized. Dose linearity was observed for doses up to 50 mg/kg and pulmonary penetration ratios (area under the concentration-time curve in ELF from 0 to 24 h [AUCELF,0-24]/area under the concentration time curve in serum from 0 to 24 h [AUCserum,0-24]) ranged from 2.5 to 2.8. Pharmacokinetic-pharmacodynamics (PK-PD) index values in ELF for various dose regimens against different A. baumannii isolates were calculated. The maximum efficacy at 24 h was approximately 1.5-log-unit reduction of pulmonary bacterial burdens from baseline. The AUC/MIC ratio was the PK-PD index most closely correlating to the bacterial burden (r(2) = 0.81). The required AUCELF,0-24/MIC for maintaining stasis and achieving 1-log-unit reduction were 140 and 410, respectively. These findings could guide the treatment of infections caused by A. baumannii using minocycline in the future. Additional studies to examine resistance development during therapy are warranted. Copyright © 2017 American Society for Microbiology.

  12. Diversity of mechanisms conferring resistance to β-lactams among OXA-23-producing Acinetobacter baumannii clones.

    Science.gov (United States)

    Cardoso, Juliana Provasi; Cayô, Rodrigo; Girardello, Raquel; Gales, Ana Cristina

    2016-05-01

    A total of 31 unrelated OXA-23-producing Acinetobacter baumannii strains isolated from 14 hospitals located in distinct Brazilian regions were evaluated in this study. These isolates were grouped into 12 different sequence types (STs), of which 7 had unique allelic sequences (ST188, ST189, ST190, ST191, ST192, ST228, and ST299). Most isolates belonged to the clonal complex CC79 followed by CC15 and CC1. Only polymyxin B and minocycline showed good activity against the OXA-23-producing A. baumannii clones. The ISAba1 upstream blaOXA-23, blaOXA-51-like, or ampC was found in 100%, 54.8%, and 77.4% of the isolates, respectively. High resistance rates to ceftazidime and cefotaxime were observed among those isolates possessing ISAba1 upstream ampC, in contrast to those isolates that did not carry this configuration. Moreover, a ≥2 Log2 decrease in the MICs of meropenem and ceftazidime was observed in the presence of phenyl-arginine-β-naphthylamide for 80.6% and 54.8% of isolates, respectively. Overexpression of the adeB was observed in 61.3% of isolates, particularly among those isolates belonging to the ST1 (CC1). It was also verified that ompW was down-regulated in all isolates belonging to the ST15 (CC15). On the other hand, carO and omp33-36 genes were overexpressed in 48.4% and 58.1% of the isolates, respectively. In this study, we show that overexpression of AdeABC system could significantly contribute for resistance to meropenem and ceftazidime among OXA-23-producing A. baumannii clones in Brazil, demonstrating the complexity involved in the β-lactam resistance in such isolates.

  13. 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.

  14. Changes of antimicrobial resistance among acinetobacter baumannii isolated from the patients in the year of 2008 to 2013%2008~2013年鲍曼不动杆菌的耐药性变迁

    Institute of Scientific and Technical Information of China (English)

    宋育明; 杨色娟; 吴秀益

    2015-01-01

    Objective:To analyze the trend of the antibiotic resistance of acinetobacter baumannii in my Hospital during 2007 to 2011. Methods:The identification of bacteria and susceptibility test were perfomed using automatic bicanalysis-Vitek-2. Results:Acinetobacter baumannii resistance increased year by year,acinetobacter baumannii have a higher resistance in addition to amikacin, Aztreonam up to 96. 8%. Conclusion:Acinetobacter baumannii resistance in severe and resistant rate to rise year by year,clinicians should take the necessary measures to slow down the deterioration,bacterial resistance.%目的:对某院2008年~2013年分离出的鲍曼不动杆菌的耐药性作回顾性分析,为临床合理选用抗菌药物提供依据。方法:应用VITEK2全自动微生物分析仪对菌株进行培养鉴定及药敏试验。结果:鲍曼不动杆菌的耐药率呈逐年上升趋势,除阿米卡星外均有较高的耐药性,氨曲南高达96.8%。结论:鲍曼不动杆菌的耐药性严重且耐药率逞逐年上升趋势,临床应采取必要措施,以减缓其耐药性的恶化。

  15. 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.

  16. 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.

  17. Clonal evolution multi-drug resistant Acinetobacter baumannii by pulsed-field gel electrophoresis

    Directory of Open Access Journals (Sweden)

    P Mohajeri

    2015-01-01

    Full Text Available Background: Acinetobacter baumannii is usually multi-drug resistant (MDR, including third generation cephalosporins, amino glycosides and fluoroquinolone. Resistance to these antibiotics is mediated by multiple factors such as: lactamases, efflux pumps and other mechanisms of resistance. Pulsed-field gel electrophoresis (PFGE was then used to investigate the genetic relationships among the MDR isolates. Aim: The aim of this study was to determine MDR isolates and the existence of OXAs genes among MDR isolates of A. baumannii collected from Kermanshah hospitals in west of Iran. Materials and Methods: Forty-two MDR A. baumannii were collected from patients at Kermanshah hospitals. The isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics by disk diffusion method was determined. Polymerase chain reaction (PCR was performed for detection of blaOXA-23-like , blaOXA-24-like , blaOXA-51-like and blaOXA-58-like betalactamase genes in isolates and clonal relatedness was done by PFGE (with the restriction enzyme ApaI and patterns analyzed by Bionumeric software. Results: This study showed high resistant to ciprofloxacin, piperacillin, ceftazidime and also resistant to other anti-microbial agents and more spread blaOXA-23-like gene (93% in MDR isolate. The PFGE method obtained six clones: A (10, B (9, C (5, D (4, E (11 and F (3 that clone E was outbreak and dominant in different wards of hospitals studied. Conclusion: An isolate from the emergency ward of these hospitals had indistinguishable isolates PFGE profile and similar resistance profile to isolates from intensive care unit (ICU, suggesting likely transmission from ICU to emergency via patient or hospital staff contact.

  18. Evaluación microbiológica y epidemiológica de los clones de Acinetobacter baumannii resistentes a los carbapenemes aislados en la unidad de cuidados intensivos de un Hospital Universitario de la ciudad de Buenos Aires Microbiological and epidemiological evaluation of carbapenem-resistant Acinetobacter baumannii clones isolated at an intensive care unit of a University Hospital in Buenos Aires city

    Directory of Open Access Journals (Sweden)

    C. H. Rodriguez

    2009-09-01

    Full Text Available Entre junio y diciembre de 2004 se estudiaron 33 aislamientos de Acinetobacter baumannii resistentes a los carbapenemes, aislados de materiales clínicos de 29 pacientes internados en la unidad de cuidados intensivos del Hospital de Clínicas de la Universidad de Buenos Aires. La distribución clonal de esos aislamientos fue la siguiente: clon I (n = 14, clon IV (n = 7, clon III (n = 6, clon VI (n = 3, clon II (n = 2 y clon X (n = 1.Veintiún aislamientos se recuperaron de materiales del tracto respiratorio inferior, 11 de ellos pertenecieron al clon I. Casi todos los aislamientos pertenecientes al clon III (5/6 se recuperaron de materiales no respiratorios, y todos los del clon IV se recuperaron de pacientes que no recibieron imipenem. En los aislamientos pertenecientes a los clones I y III se observó una mayor adherencia a catéteres, principalmente en los asociados con bacteriemias. La mayoría de los aislamientos de los clones I y IV sobrevivieron en materiales inertes durante un período superior a los 5 días. La totalidad de los aislamientos del clon III fueron sensibles a colistina, gentamicina y levofloxacina, mientras que los del clon I y la mayoría de los del clon IV sólo fueron sensibles a colistina y tetraciclinas.From June to December 2004, thirty-three carbapenem-resistant Acinetobacter baumannii isolates recovered from twenty nine patients at the intensive care unit in Hospital de Clínicas, Universidad de Buenos Aires, were studied. The isolates were categorized by molecular methods as: clone I (n = 14, clon IV (n = 7, clone III (n = 6, clone VI (n = 3, clone II (n = 2 and clone X (n = 1. Twenty one isolates were recovered from lower respiratory tract samples, 11 of which belonged to clon I. Clone III isolates were mainly recovered from non-respiratory samples (5/6. Clone IV isolates were recovered from patients not receiving previous imipenem therapy. The majority of the isolates belonging to clones I and IV were able to

  19. 产金属β-内酰胺酶的鲍氏不动杆菌在我国内地出现%Emerging metallo-β-lactamases in clinical isolates of Acinetobacter baumannii in China inland

    Institute of Scientific and Technical Information of China (English)

    宗志勇; 吕晓菊; 高燕渝; 俞汝佳

    2004-01-01

    Acquired metallo-β-lactamases (MBLs) are emerging globally and can confer resistance to near all β-lactams. Recently, MBLs were found in Pseudomonas aeruginosa and Citrobacter youngae from China inland, but not in Acinetobacter baumannii. In 2002 and 2003, a few imipenem-resistant and/or ceftazidime-highly-resistant A. baumannii were isolated from clinical specimens in West China Hospital, Sichuan University. By agar dilution method used imipenem with imipenem plus EDTA-1, 10-phenanthroline and/or ceftazidime with ceftazidime plus EDTA-1, 10-phenanthroline, MBLs were detected in 12 nonreplicate A. baumannii isolates. Most of the MBL producers were isolated from sputa of patients with ventilation-associated pneumonia in ICU. PCR for amplifying blaLMP-4 and blavLM-2 for the 12 MBL-producing isolates failed. It demonstrates that MBLs produced by the isolates are MBLs other than IMP-4, VIM-2, VIM-3 and VIM-6.This study is the first report that MBLs are found in A. baumannii in China inland.%获得性金属β-内酰胺酶(金属酶)已经在全球出现,并且能导致对几乎所有β-内酰胺类抗生素耐药.近来,金属酶已经在我国的铜绿假单胞菌和杨氏柠檬酸菌中发现,但尚未在鲍氏不动杆菌中发现.2002和2003年,从四川大学华西医院的临床标本中分离出一些亚胺培南耐药或头孢他啶高度耐药的鲍氏不动杆菌菌株.通过亚胺培南联合亚胺培南-EDTA-邻二氮菲或头孢他啶联合头孢他啶-EDTA-邻二氮菲的琼脂稀释法,检测出12株不重复的鲍氏不动杆菌产金属酶.这些产金属酶的菌株主要分离自机械通气相关性肺炎患者的痰标本.PCR扩增IMP-4和VIM-2的编码基因无阳性结果.说明这些菌株所产的金属酶并非IMP-4、VIM-2、VIM-3和VIM-6.这是首次在我国内地发现有产金属酶的鲍氏不动杆菌.

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  2. 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.

  3. 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.

  4. 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.

  5. Antimicrobial Activity of Gallium Protoporphyrin IX against Acinetobacter baumannii Strains Displaying Different Antibiotic Resistance Phenotypes.

    Science.gov (United States)

    Arivett, Brock A; Fiester, Steven E; Ohneck, Emily J; Penwell, William F; Kaufman, Cynthia M; Relich, Ryan F; Actis, Luis A

    2015-12-01

    A paucity of effective, currently available antibiotics and a lull in antibiotic development pose significant challenges for treatment of patients with multidrug-resistant (MDR) Acinetobacter baumannii infections. Thus, novel therapeutic strategies must be evaluated to meet the demands of treatment of these often life-threatening infections. Accordingly, we examined the antibiotic activity of gallium protoporphyrin IX (Ga-PPIX) against a collection of A. baumannii strains, including nonmilitary and military strains and strains representing different clonal lineages and isolates classified as susceptible or MDR. Susceptibility testing demonstrated that Ga-PPIX inhibits the growth of all tested strains when cultured in cation-adjusted Mueller-Hinton broth, with a MIC of 20 μg/ml. This concentration significantly reduced bacterial viability, while 40 μg/ml killed all cells of the A. baumannii ATCC 19606(T) and ACICU MDR isolate after 24-h incubation. Recovery of ATCC 19606(T) and ACICU strains from infected A549 human alveolar epithelial monolayers was also decreased when the medium was supplemented with Ga-PPIX, particularly at a 40-μg/ml concentration. Similarly, the coinjection of bacteria with Ga-PPIX increased the survival of Galleria mellonella larvae infected with ATCC 19606(T) or ACICU. Ga-PPIX was cytotoxic only when monolayers or larvae were exposed to concentrations 16-fold and 1,250-fold higher than those showing antibacterial activity, respectively. These results indicate that Ga-PPIX could be a viable therapeutic option for treatment of recalcitrant A. baumannii infections regardless of the resistance phenotype, clone lineage, time and site of isolation of strains causing these infections and their iron uptake phenotypes or the iron content of the media.

  6. 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

  7. 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.

  8. Immunization with lipopolysaccharide-deficient whole cells provides protective immunity in an experimental mouse model of Acinetobacter baumannii infection.

    Science.gov (United States)

    García-Quintanilla, Meritxell; Pulido, Marina R; Pachón, Jerónimo; McConnell, Michael J

    2014-01-01

    The increasing clinical importance of infections caused by multidrug resistant Acinetobacter baumannii warrants the development of novel approaches for prevention and treatment. In this context, vaccination of certain patient populations may contribute to reducing the morbidity and mortality caused by this pathogen. Vaccines against Gram-negative bacteria based on inactivated bacterial cells are highly immunogenic and have been shown to produce protective immunity against a number of bacterial species. However, the high endotoxin levels present in these vaccines due to the presence of lipopolysaccharide complicates their use in human vaccination. In the present study, we used a laboratory-derived strain of A. baumannii that completely lacks lipopolysaccharide due to a mutation in the lpxD gene (IB010), one of the genes involved in the first steps of lipopolysaccharide biosynthesis, for vaccination. We demonstrate that IB010 has greatly reduced endotoxin content (infection tissue bacterial loads and significantly lower serum levels of the pro-inflammatory cytokines IL-1β, TNF-α and IL-6 compared to control mice in a mouse model of disseminated A. baumannii infection. Importantly, immunized mice were protected from infection with the ATCC 19606 strain and an A. baumannii clinical isolate. These data suggest that immunization with inactivated A. baumannii whole cells deficient in lipopolysaccharide could serve as the basis for a vaccine for the prevention of infection caused by A. baumannii.

  9. Structure of shikimate kinase, an in vivo essential metabolic enzyme in the nosocomial pathogen Acinetobacter baumannii, in complex with shikimate.

    Science.gov (United States)

    Sutton, Kristin A; Breen, Jennifer; MacDonald, Ulrike; Beanan, Janet M; Olson, Ruth; Russo, Thomas A; Schultz, L Wayne; Umland, Timothy C

    2015-08-01

    Acinetobacter baumannii is an opportunistic Gram-negative pathogen that is an important cause of healthcare-associated infections exhibiting high mortality rates. Clinical isolates of multidrug-resistant (MDR) and extremely drug-resistant (XDR) A. baumannii strains are increasingly being observed. Compounding this concern is the dearth of new antibacterial agents in late-stage development that are effective against MDR and XDR A. baumannii. As part of an effort to address these concerns, two genes (aroA and aroC) of the shikimate pathway have previously been determined to be essential for the growth and survival of A. baumannii during host infection (i.e. to be essential in vivo). This study expands upon these results by demonstrating that the A. baumannii aroK gene, encoding shikimate kinase (SK), is also essential in vivo in a rat soft-tissue infection model. The crystal structure of A. baumannii SK in complex with the substrate shikimate and a sulfate ion that mimics the binding interactions expected for the β-phosphate of ATP was then determined to 1.91 Å resolution and the enzyme kinetics were characterized. The flexible shikimate-binding domain and LID region are compared with the analogous regions in other SK crystal structures. The impact of structural differences and sequence divergence between SKs from pathogenic bacteria that may influence antibiotic-development efforts is discussed.

  10. Fulminant endocarditis and disseminated infection caused by carbapenem-resistant Acinetobacter baumannii in a renal-pancreas transplant recipient

    Science.gov (United States)

    Patel, G.; Perez, F.; Hujer, A.M.; Rudin, S.D.; Augustine, J.J.; Jacobs, G.H.; Jacobs, M.R.; Bonomo, R.A.

    2015-01-01

    Acinetobacter baumannii is an important cause of healthcare-associated infections, and is particularly problematic among patients who undergo organ transplantation. We describe a case of fulminant sepsis caused by carbapenem-resistant A. baumannii harboring the blaOXA-23 carbapenemase gene and belonging to international clone II. This isolate led to the death of a patient 6 days after simultaneous kidney-pancreas transplantation. Autopsy findings revealed acute mitral valve endocarditis, myocarditis, splenic and renal emboli, peritonitis, and pneumonia. This case highlights the severe nature of certain A. baumannii infections and the vulnerability of transplanted patients to the increasingly intractable ‘high-risk’ clones of multidrug-resistant organisms. PMID:25661804

  11. High prevalence of extensively drug-resistant and metallo beta-lactamase-producing clinical Acinetobacter baumannii in Iran.

    Science.gov (United States)

    Maspi, Hossein; Mahmoodzadeh Hosseini, Hamideh; Amin, Mohsen; Imani Fooladi, Abbas Ali

    2016-09-01

    Acinetobacter species particularly Acinetobacter baumannii (A. baumannii) have been widely reported as broad-spectrum antibiotic resistant pathogens. Expression of various types of metallo beta-lactamases (MBL), classified as Ambler class B, has been associated with carbapenem resistance. Here, we attempted to assess the frequency of extensively drug-resistant (XDR) and MBL-producing A. baumannii among clinical isolates. 86 clinical A. baumannii strains were collected from 2014 to 2015 and their susceptibility to meropenem (10 μg), imipenem (10 μg), azteronem (30 μg), pipracillin (100 μg) tazobactam (110 μg), tobramycin (10 μg), fosfomycin (200 μg), rifampicin (5 μg), colistin (10 μg), tigecycline (15 μg), sulbactam/ampicillin (10 μg + 10 μg) and polymixin B (300 U) was evaluated using disk diffusion method. The MBL-producing isolates were screened using combined disc diffusion method. Furthermore, the presence of blaVIM, blaIMP, blaSPM, blaGIM, blaSIM and blaNDM was detected by PCR. 34.9% of isolates were recovered from bronchoalveolar lavage (BAL). 81 (94.2%) and 62 (71.2%) isolates were multidrug resistance (MDR) and XDR, respectively. 44 (51.2%) and 65 (75.6%) isolates were MBL-producing strains with resistance to imipenem and meropenem, respectively. 2 (2.3%), 13 (15.1%), 2 (2.3%), 4 (4.7%) and 2 (2.3%) isolates carried blaVIM, blaIMP, blaSPM, blaGIM and blaSIM genes, respectively. Our data showed that the rate of XDR and MBL A. baumannii is on the rise.

  12. Antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model: implications for prophylaxis and treatment of combat-related wound infections.

    Science.gov (United States)

    Zhang, Yunsong; Zhu, Yingbo; Gupta, Asheesh; Huang, Yingying; Murray, Clinton K; Vrahas, Mark S; Sherwood, Margaret E; Baer, David G; Hamblin, Michael R; Dai, Tianhong

    2014-06-15

    In this study, we investigated the utility of antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model. A bioluminescent clinical isolate of multidrug-resistant A. baumannii was obtained. The susceptibility of A. baumannii to blue light (415 nm)-inactivation was compared in vitro to that of human keratinocytes. Repeated cycles of sublethal inactivation of bacterial by blue light were performed to investigate the potential resistance development of A. baumannii to blue light. A mouse model of third degree burn infected with A. baumannii was developed. A single exposure of blue light was initiated 30 minutes after bacterial inoculation to inactivate A. baumannii in mouse burns. It was found that the multidrug-resistant A. baumannii strain was significantly more susceptible than keratinocytes to blue light inactivation. Transmission electron microscopy revealed blue light-induced ultrastructural damage in A. baumannii cells. Fluorescence spectroscopy suggested that endogenous porphyrins exist in A. baumannii cells. Blue light at an exposure of 55.8 J/cm(2) significantly reduced the bacterial burden in mouse burns. No resistance development to blue light inactivation was observed in A. baumannii after 10 cycles of sublethal inactivation of bacteria. No significant DNA damage was detected in mouse skin by means of a skin TUNEL assay after a blue light exposure of 195 J/cm(2).

  13. INHIBITION OF Acinetobacter baumannii ADHESION BY ANTI-FIMBRIAL ANTIBODY: THE FIMBRIAL ANTIGEN EFFECTIVENESS

    Directory of Open Access Journals (Sweden)

    Hadeel K. Musafer

    2013-01-01

    Full Text Available Collecting samples of Acinetobacter baumannii taken from different clinical cases of wounds, septicemia, and urinary tract infections. That was accomplished by taking (296 samples from Baghdad educational hospital and Ibn-al-Baladi hospital. Samples were cultured on solid media (McConkey and blood agars, and according to microscopical, cultural, and biochemical identification, in addition to using API 20-E system, (21 isolates of A. baumannii were identified and in percentage of 47.619, 9.523, 14.285, and 28.571 for wound, blood, sputum, and urine samples, respectively. Methods: detection of fimbriated bacterial isolates among 21 isolates, and all those isolated were fimbriae forming isolates; isolate number (9 was selected as an effective isolate in formation of fimbriae. Non-forming fimbriae isolate of Shigella flexneri is used as negative control. Results and Conclusion: the average of adherence of fimbriated bacterial cell with human epithelial cells was reached (50 adherent bacterial cell per epithelial cell compared with the average of adherence of control isolate (12 adherent bacterial cell per epithelial cell, the inhibition processes are performed: Inhibition of bacterial adherence by specific antibodies of fimbriae antigen showed inhibition effect of adherence in respect to fimbriated isolate A. baumannii 9 also the subminimum inhibitory concentration for four antibiotics (Gentamicin, Tobramycin, Cefepime, and Amikacin inhibit the adherence of fimbriated isolate. The isolates (used in the study have the ability to agglutinate Saccharomyces cerevisiae and human red blood corpuscles (RBCs. The study of effect of different fimbriae extract concentrations (25, 50, 100 μg/ml on immune cells; consequently, reached to the following results: Concentrations of (25, 50, 100 μg/ml showed a negative effect on lymphocyte and PMNs viability which increased significantly (P≤0.05 with increasing of fimbriae extract concentration. On the other hand

  14. Identification and characteristics of imipenem-resistant Acinetobacter baumannii in surgical wards in a Chinese university hospital.

    Science.gov (United States)

    Wang, Dalin; Ma, Linlin; Wu, Zhenyu; Li, Mingcheng; Li, Xiaohan; Zhang, Wei; Chen, Kun

    2015-03-01

    The aim of this study was to investigate the prevalence and characteristics of imipenem-resistant Acinetobacter baumanni isolated from surgical wards in a university hospital, China. A total of 143 non-duplicate A. baumannii were isolated from 517 inpatients in surgery intensive care units (ICUs), burn wards, and general surgery wards. Of these, 102 isolates of A. baumannii (71.3%) were resistant to imipenem. Among imipenem-resistant isolates, all isolates were resistant to almost all antimicrobial agents except polymyxin E, all isolates were positive for blaOXA-23 and blaOXA-51 in addition to ISAba1, 52 (51%) were positive for blaOXA-58, 8 (7.8%) contained blaVIM-2, which co-harbored with blaOXA-58. Molecular typing revealed the presence of three clones among imipenem-resistant isolates. This study confirmed that A. baumannii strains harboring OXA or VIM type β-lactamases are widely distributed throughout the surgery wards. The data demonstrate that there was a high prevalence of imipenem-resistant A. baumannii infection in the region.

  15. Concurrent outbreak of multidrug-resistant and susceptible subclones of Acinetobacter baumannii affecting different wards of a single hospital.

    Science.gov (United States)

    Maslow, Joel N; Glaze, Thomas; Adams, Pamela; Lataillade, Max

    2005-01-01

    Acinetobacter baumannii has emerged as an opportunistic pathogen among acutely ill patients, especially those with thermal injury. A prospective 8-month study was conducted to describe the clinical and molecular epidemiology of multidrug-resistant A. baumannii affecting a single hospital. Univariate analysis comparing SmaI macrorestriction patterns of A. baumannii generated by pulsed-field gel electrophoresis (PFGE) versus clinical and demographic risk factors. A total of 200 isolates from 76 patients were collected, of which 185 isolates from 76 patients were analyzed by PFGE. A total of 17 distinct PFGE clonal types were identified. One clonal type (strain A) represented 129 isolates from 49 patients. A group of related clonal types (strain A variants) were identified as 40 isolates from 20 patients. The only risk factor other than geographic location associated with the presence of strain A was prior treatment with antibiotics active against gram-negative bacteria (P = .0015). The two clonal types differed in antibiotic resistance profiles: 25% of strain A isolates, the dominant strain in the burn unit, were susceptible to at least one antibiotic tested. In contrast, approximately 80% of the other strain types were susceptible to at least one antibiotic and were cultured from patients admitted elsewhere in the hospital. No combination of antibiotics was observed to yield additive or synergistic activity. Clonally related strains of Acinetobacter that differ in susceptibility patterns may coexist within a single hospital, dependent on the selective pressure related to antibiotic exposure.

  16. Simultaneous identification of multiple β-lactamases in Acinetobacter baumannii in relation to carbapenem and ceftazidime resistance, using liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Trip, H.; Mende, K.; Majchrzykiewicz-Koehorst, J.A.; Sedee, N.J.A.; Hulst, A.G.; Jansen, H.J.; Murray, C.K.; Paauw, A.

    2015-01-01

    Shotgun proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to detect β-lactamases in clinical Acinetobacter baumannii isolates. The correlation of the detection of β-lactamase proteins (rather than PCR detection of the corresponding genes) with the resistance phen

  17. 脑外科 ICU 患者痰标本中鲍曼不动杆菌的临床意义分析%Analysis on clinical significance of Acinetobacter baumannii isolated from patients′sputum samples in cerebral surgery ICU

    Institute of Scientific and Technical Information of China (English)

    凌玲; 董兰梅

    2015-01-01

    目的:了解该院脑外科重症监护病房(ICU)患者痰标本中分离的112株鲍曼不动杆菌的临床分布和耐药情况,为临床治疗合理使用抗菌药物提供依据。方法对112例鲍曼不动杆菌进行回顾性分析,采用 VITEK2-Compact 全自动微生物分析仪进行细菌鉴定及药敏试验,结合 K-Β法作补充对照,使用 Whonet5.6软件进行统计分析。结果112株鲍曼不动杆菌中75株(67.0%)为多重耐药菌,8株(7.1%)为泛耐药菌。药敏结果中耐药率高达100%是美洛西林、哌拉西林以及呋喃妥因,耐药率较低的多粘菌素 B 为2.7%,米诺环素和头孢哌酮/舒巴坦次之,耐药率分别为4.5%和10.7%。结论脑外科 ICU 患者感染的鲍曼不动杆菌耐药现象严重,米诺环素、多黏菌素 B、头孢哌酮/舒巴坦对临床分离鲍曼不动杆菌具有良好的抗菌活性,可作为治疗选择药物,临床应加强检测,合理使用抗菌药物。%Objective To understand the clinical distribution and drug resistance situation of112 strains of Acinetobacter Bau-mannii isolated from the patients′sputum samples in cerebral surgery ICU in order to provide the basis for the rational use of anti-bacterial drugs in clinical therapy.Methods 112 strains of Acinetobacter Baumannii were performed the retrospective analysis.The VITEK2-Compact automatic microbiological analyzer was adopted to conduct the bacterial identification and the drug susceptibility test and the K-B method was combined as the supplement control.The Whonet 5.6 software was used for conducting the statistical analysis.Results Among 112 strains of Acinetobacter baumannii,75 strains(67.0%)were multi-drug resistant,8 strains(7.1%) were pan-resistant.The antimicrobial susceptibility tests showed that the resistant rates of Acinetobacter baumannii to mezlocillin, piperacillin and nitrofurantoin reached up to 100%.Acinetobacter Baumannii had the lower

  18. 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.

  19. Resistance and integron characterization of Acinetobacter baumannii in a teaching hospital in Chongqing, China

    Directory of Open Access Journals (Sweden)

    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.

  20. Detection and typing of integrons in epidemic strains of Acinetobacter baumannii found in the United Kingdom.

    Science.gov (United States)

    Turton, Jane F; Kaufmann, Mary E; Glover, Judith; Coelho, Juliana M; Warner, Marina; Pike, Rachel; Pitt, Tyrone L

    2005-07-01

    Integrons were sought in Acinetobacter isolates from hospitals in the United Kingdom by integrase gene PCR. Isolates were compared by pulsed-field gel electrophoresis, and most belonged to a small number of outbreak strains or clones of A. baumannii, which are highly successful in the United Kingdom. Class 1 integrons were found in all of the outbreak isolates but in none of the sporadic isolates. No class 2 integrons were found. Three integrons were identified among the main outbreak strains and clones. While a particular integron was usually associated with a strain or clone, some members carried a different integron. Some integrons were associated with more than one strain. The cassette arrays of two of the integrons were very similar, both containing gene aacC1, which confers resistance to gentamicin, two open reading frames coding for unknown products (orfX, orfX'), and gene aadA1a, which confers resistance to spectinomycin and streptomycin. The larger of these integrons had two copies of the first (orfX) of the gene cassettes coding for unknown products. The third integron, with a cassette array containing gene aacA4, which codes for amikacin, netilmicin, and tobramycin resistance; a chloramphenicol acetyltransferase, catB8; and gene aadA1, conferring resistance to spectinomycin and streptomycin, was associated with an OXA-23 carbapenemase-producing clone, which has spread rapidly in hospitals in the United Kingdom during 2003 and 2004. These integron cassette arrays have been found in other outbreak strains of A. baumannii from other countries. We conclude that integrons are useful markers for epidemic strains of A. baumannii and that integron typing provides valuable information for epidemiological studies.

  1. Analysis on the distribution and the drug resistance of clinical isolated Acinetobacter baumannii in our hospital from 2013 to 2015%2013~2015年临床分离的鲍曼不动杆菌的分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    吴振安

    2016-01-01

    目的:了解该院临床分离的鲍曼不动杆菌的分布特点及对临床常用抗菌药物耐药率的变化,为临床合理用药、院内感染控制提供依据。方法应用珠海迪尔体外细菌检测专用系统进行细菌鉴定和药敏试验,用WHONET 5.6软件进行数据分析。结果院内3年间分离的鲍曼不动杆菌主来源于痰液(82.98%~88.76%)。2015年分离的70株鲍曼不动杆菌对亚胺培南等17种抗菌药物的耐药率(5.7%~41.4%)低于2014年分离的94株鲍曼不动杆菌对亚胺培南等17种抗菌药物的耐药率(6.4%~47.9%) ,而高于2013年分离的89株鲍曼不动杆菌对亚胺培南等17种抗菌药物的耐药率(2.2%~18.0%)。鲍曼不动杆菌对米诺环素、多粘菌素B、头孢哌酮/舒巴坦、亚胺培南的总耐药率较低,分别为4.7%、5.1%、10.3%、15.4%;对四环素、氨苄西林/舒巴坦、哌拉西林、环丙沙星的总耐药率较高,分别为34.4%、31.2%、31.2%、29.3%。结论鲍曼不动杆菌主要引起呼吸道感染,本院临床分离的鲍曼不动杆菌对多数常用抗菌药物的耐药率均低于文献报道。加强耐药性监测,依据药敏试验结果合理使用抗菌药物,做好消毒隔离工作,可预防和减少院内多重耐药鲍曼不动杆菌的产生和传播。%Objective To investigate the distribution and drug resistances of clinical isolated Acinetobacter baumannii to the common antimicrobial ,and to provide theoretical basis for rational use of antibiotics and nosocomial infection control .Methods DL identification system was used for the identification of strains and drug sensitive test .The results of drug sensitivity were analyzed by WHONET 5 .6 software .Results Among the Acinetobacter baumannii isolates collected from 2013 to 2015 ,82 .98% -88 .76%were obtained from sputum .The drug resistances rates (5 .7%‐41 .4% ) of 70

  2. Spread of imipenem-resistant Acinetobacter baumannii co-expressing OXA-23 and GES-11 carbapenemases in Lebanon.

    Science.gov (United States)

    Hammoudi, D; Moubareck, C Ayoub; Hakime, N; Houmani, M; Barakat, A; Najjar, Z; Suleiman, M; Fayad, N; Sarraf, R; Sarkis, D Karam

    2015-07-01

    The acquisition of carbapenemases by Acinetobacter baumannii is reported increasingly worldwide, but data from Lebanon are limited. The aims of this study were to evaluate the prevalence of imipenem-resistant A. baumannii in Lebanon, identify resistance determinants, and detect clonal relatedness. Imipenem-resistant A. baumannii were collected from nine Lebanese hospitals during 2012. Antimicrobial susceptibility, the cloxacillin effect, and ethylenediaminetetraacetic acid (EDTA) synergy were determined. Genes encoding carbapenemases and insertion sequence ISAba1 were screened via PCR sequencing. ISAba1 position relative to genes encoding Acinetobacter-derived cephalosporinases (ADCs) and OXA-23 was studied by PCR mapping. Clonal linkage was examined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Out of 724 A. baumannii isolated in 2012, 638 (88%) were imipenem-resistant. Of these, 142 were analyzed. Clavulanic acid-imipenem synergy suggested carbapenem-hydrolyzing extended-spectrum β-lactamase. A positive cloxacillin test indicated ADCs, while EDTA detection strips were negative. Genotyping indicated that 90% of isolates co-harbored blaOXA-23 and blaGES-11. The remaining strains had blaOXA-23, blaOXA-24, blaGES-11, or blaOXA-24 with blaGES-11. ISAba1 was located upstream of blaADC and blaOXA-23 in 97% and 100% of isolates, respectively. ERIC-PCR fingerprinting revealed 18 pulsotypes spread via horizontal gene transfer and clonal dissemination. This survey established baseline evidence of OXA-23 and GES-11-producing A. baumannii in Lebanon, indicating the need for further surveillance. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Antimicrobial Activity of Nanoemulsion in Combination with Cetylpyridinium Chloride in Multidrug-Resistant Acinetobacter baumannii

    Science.gov (United States)

    2013-08-01

    enteric Gram - negative bacilli . J. Appl. Mi- crobiol. 89:397– 403. 10. Hemmila MR, Mattar A, Taddonio MA, Arbabi S, Hamouda T, Ward PA, Wang SC, Baker...utilization of nanoemulsions against the antibiotic-resistant forms of A. baumannii. Over the past 15 years, Acinetobacter baumannii (an aerobic, Gram ... negative coccobacillus) has become an emerging problematic pathogen with a wide array of antibiotic resistance (1), representing a serious threat not

  4. Facial ulcerations due to Acinetobacter baumannii: Vessel thrombosis with bacterial mycelia

    Directory of Open Access Journals (Sweden)

    Dong Ming Li

    2014-01-01

    Full Text Available A 14-year-old girl presented with a 2-week history of progressive facial ulcerations that did not respond to cephalexin and topical dexamethasone. Biopsy on the ulcer showed rod-shaped bacteria and actinomycetes-like mycelia in the vessel walls and within thrombi. Tissue culture yielded Acinetobacter baumannii, which was resistant to cephalexin. A favourite outcome was achieved with minocycline treatment. This is the first case report of A. baumannii-related vasculitis.

  5. 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

  6. Variation in the OC locus of Acinetobacter baumannii genomes predicts extensive structural diversity in the lipooligosaccharide.

    Directory of Open Access Journals (Sweden)

    Johanna J Kenyon

    Full Text Available Lipooligosaccharide (LOS is a complex surface structure that is linked to many pathogenic properties of Acinetobacter baumannii. In A. baumannii, the genes responsible for the synthesis of the outer core (OC component of the LOS are located between ilvE and aspS. The content of the OC locus is usually variable within a species, and examination of 6 complete and 227 draft A. baumannii genome sequences available in GenBank non-redundant and Whole Genome Shotgun databases revealed nine distinct new types, OCL4-OCL12, in addition to the three known ones. The twelve gene clusters fell into two distinct groups, designated Group A and Group B, based on similarities in the genes present. OCL6 (Group B was unique in that it included genes for the synthesis of L-Rhamnosep. Genetic exchange of the different configurations between strains has occurred as some OC forms were found in several different sequence types (STs. OCL1 (Group A was the most widely distributed being present in 18 STs, and OCL6 was found in 16 STs. Variation within clones was also observed, with more than one OC locus type found in the two globally disseminated clones, GC1 and GC2, that include the majority of multiply antibiotic resistant isolates. OCL1 was the most abundant gene cluster in both GC1 and GC2 genomes but GC1 isolates also carried OCL2, OCL3 or OCL5, and OCL3 was also present in GC2. As replacement of the OC locus in the major global clones indicates the presence of sub-lineages, a PCR typing scheme was developed to rapidly distinguish Group A and Group B types, and to distinguish the specific forms found in GC1 and GC2 isolates.

  7. High prevalence of the PER-1 gene among carbapenem-resistant Acinetobacter baumannii in Riyadh, Saudi Arabia.

    Science.gov (United States)

    Aly, M M; Abu Alsoud, N M; Elrobh, M S; Al Johani, S M; Balkhy, H H

    2016-11-01

    The prevalence of carbapenem-resistant Acinetobacter baumannii in Saudi Arabia and their resistance genetic mechanisms are yet to be identified. We studied the prevalence and genetic diversity of extended-spectrum beta-lactamase genes, particularly the PER-1 gene, among carbapenem-resistant A. baumannii strains from patients at a tertiary care hospital in Riyadh, Saudi Arabia between 2006 and 2014. Fresh subcultured samples were tested for antimicrobial susceptibility minimum inhibitory concentration (MIC). Total genomic DNA was extracted from each isolate and further used for polymerase chain reaction (PCR) genotyping, sequence-based typing (SBT) of PER-1 and OXA-51-like gene, and multilocus sequence typing (MLST) of positive isolates. Randomly selected clinical isolates (n = 100) were subjected to MLST. A total of 503 isolates were characterized as multidrug-resistant (MDR) using the MIC. Isolates were further PCR tested for bla -TEM and bla -PER-1 resistance genes (n = 503). The genotyping results showed that 68/503 (14 %) isolates were positive to bla TEM. The genotyping results of PER-1-like genes showed that 384/503 (76.3 %) were positive among MDR Acinetobacter isolates. Based on SBT, the majority of these isolates were clustered into three main groups including isolates harboring PER-1: AB11 (bla -PER-1), isolate AB16 (bla -PER-1), and, finally, the plasmid pAB154 (bla -PER-7). Remarkably, many isolates were concealing the PER-1 gene and harboring the TEM resistance genes as well. MLST results for selected isolates (n = 100) identified four main sequence types (STs: 2, 19, 20, and 25) and four novel isolates (ST 486-489). We report 76.3 % prevalence of the PER-1 resistance gene among Acinetobacter clinical isolates from Riyadh, Saudi Arabia. Further work is needed to explore the clinical risks and patient outcome with such resistance related to healthcare-associated infections and investigate the genetic and molecular mechanisms that confer the MDR

  8. 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.

  9. Transmission Electron Microscopic Morphological Study and Flow Cytometric Viability Assessment of Acinetobacter baumannii Susceptible to Musca domestica cecropin

    Directory of Open Access Journals (Sweden)

    Shuiqing Gui

    2014-01-01

    Full Text Available Multidrug-resistant (MDR Acinetobacter baumannii infections are difficult to treat owing to the extremely limited armamentarium. Expectations about antimicrobial peptides' use as new powerful antibacterial agents have been raised on the basis of their unique mechanism of action. Musca domestica cecropin (Mdc, a novel antimicrobial peptide from the larvae of Housefly (Musca domestica, has potently active against Gram-positive and Gram-negative bacteria standard strain. Here we evaluated the antibacterial activity of Mdc against clinical isolates of MDR-A. baumannii and elucidate the related antibacterial mechanisms. The minimal inhibitory concentration (MIC of Mdc was 4 μg/mL. Bactericidal kinetics of Mdc revealed rapid killing of A. baumannii (30 min. Flow cytometry using viability stain demonstrated that Mdc causes A. baumannii membrane permeabilization in a concentration- and time-dependent process, which correlates with the bactericidal action. Moreover, transmission electron microscopic (TEM examination showed that Mdc is capable of disrupting the membrane of bacterial cells, resulting in efflux of essential cytoplasmic components. Overall, Mdc could be a promising antibacterial agent for MDR-A. baumannii infections.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Inspection and analysis of antibiotic resistance of Acinetobacter baumannii%临床鲍曼不动杆菌的耐药性监测与分析

    Institute of Scientific and Technical Information of China (English)

    卢亚林; 游升荣

    2012-01-01

    Objective: To investigate the isolate situation and antibiotic resistance of Acinetobacter baumannii in a "AAA" hospital in recent three years, so as to know the resistant trend of Acinetobacter baumannii. Methods: From January 2009 to December 2011, isolation rate and resistance rate for 15 antibiotics of Acinetobacter baumannii in some "AAA" hospital were calculated to analyze the antibiotic resistance and variance trend of Acinetobacter baumannii. Results: The isolate rates of Acinetobacter baumannii were7.4% , 10.5% and 14.0% in 2009,2010 and 2011. The resistant rate variance of eleven antibiotics had significant difference( P <0.05 ) . The proportion of Acinetobacter baumannii resistant to more than five antibiotics were 19. 4% ,33. 6% and 45. 9% ,showing uplifted trend year by year. Conclusion: Acinetobacter baumannii has become an important pathogen in clinical infection, whose resistance to common - used antibiotics rose year after year,and multi - drug resistance was more and more severe.%目的:调查3年来鲍曼不动杆菌的检出情况及其对常用抗生素的耐药现状,了解鲍曼不动杆菌的耐药性变迁趋势.方法:统计2009年1月-2011年12月某三甲医院鲍曼不动杆菌的检出及其对临床常用的15种抗生素的药敏情况,并对它们的耐药性及其变迁趋势进行分析.结果:3年来临床标本中鲍曼不动杆菌的检出率分别为7.4%、10.5%和14.0%,对其中11种抗生素的耐药率变化显著(P<0.05),耐5种以上抗生素的鲍曼不动杆菌所占比例分别为19.4%、33.6%和45.9%,呈现逐年明显上升的趋势.结论:鲍曼不动杆菌已成为临床感染重要的病原菌,对常用抗生素的耐药率逐年上升并日趋严重,多重耐药的情况正在进一步恶化.

  18. 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

  19. 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

  20. Acinetobacter baumannii Infection in the Neonatal Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    AMK AL Jarousha

    2008-09-01

    Full Text Available Background: To perform a prospective case control study of blood stream infection to determine the infection rate of Acine­tobac­ter baumannii and the risk factors associated with mortality."nMethods:   From February 2004 to January 2005, 579 consecutive episodes of blood stream infection were obtained at two neo­na­tal intensive care units Al Nasser and Al Shifa hospitals in Gaza City. Forty (6.9% isolates of A. baumannii were ob­tained from the neonates under 28 d. Most of the isolates (92% were from hospitalized patients in the intensive care units."nResults: Community acquired infection was 8%.  Sixty three percent of the patients were males. The isolates of A. bauman­nii were resistant to commonly used antibiotics while being sensitive to meropenem (92.5%, imipenem (90%, chloram­pheni­col (80%, ciprofloxacin (75%, gentamicin (57.5%, ceftriaxone (50%, amikacin (37.5%, cefuroxime and ce­fo­taxime (35%. Over all crude mortality rate was 20% with much higher crude mortality among patients with noso­co­mial infec­tion.  Based on logistic regression, the following factors were statistically significant: weight < 1500g, age < 7 d, mean of hospitalization equal 20 days, antibiotic use, and mechanical ventilation, when compared to the control group (P< 0.05."nConclusion:  Infection rate of nosocomial blood stream infection was considerable and alarming in neonatal intensive care unit infants and associated with a significant excess length of NICU stay and a significant economic burden.  

  1. 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.

  2. First Description of Two Sequence Type 2 Acinetobacter baumannii Isolates Carrying OXA-23 Carbapenemase in Pagellus acarne Fished from the Mediterranean Sea near Bejaia, Algeria.

    Science.gov (United States)

    Brahmi, Soumia; Touati, Abdelaziz; Cadière, Axelle; Djahmi, Nassima; Pantel, Alix; Sotto, Albert; Lavigne, Jean-Philippe; Dunyach-Remy, Catherine

    2016-04-01

    To determine the occurrence of carbapenem-resistantAcinetobacter baumanniiin fish fished from the Mediterranean Sea near the Bejaia coast (Algeria), we studied 300 gills and gut samples that had been randomly and prospectively collected during 1 year. After screening on selective agar media, using PCR arrays and whole-genome sequencing, we identified for the first time two OXA-23-producingA. baumanniistrains belonging to the widespread sequence type 2 (ST2)/international clone II and harboring aminoglycoside-modifying enzymes [aac(6')-Ib andaac(3')-I genes].

  3. Amplification of a single-locus variable-number direct repeats with restriction fragment length polymorphism (DR-PCR/RFLP) for genetic typing of Acinetobacter baumannii strains.

    Science.gov (United States)

    Nowak-Zaleska, Alicja; Krawczyk, Beata; Kotłowski, Roman; Mikucka, Agnieszka; Gospodarek, Eugenia

    2008-01-01

    In search of an effective DNA typing technique for Acinetobacter baumannii strains for hospital epidemiology use, the performance and convenience of a new target sequence was evaluated. Using known genomic sequences of Acinetobacter baumannii strains AR 319754 and ATCC 17978, we developed single-locus variable-number direct-repeat analysis using polymerase chain reaction-restriction fragment length polymorphism (DR-PCR/RFLP) method. A total of 90 Acinetobacter baumannii strains isolated from patients of the Clinical Hospital in Bydgoszcz, Poland, were examined. Initially, all strains were typed using macrorestriction analysis of the chromosomal DNA by pulsed-field gel electrophoresis (REA-PFGE). Digestion of the chromosomal DNA with the ApaI endonuclease and separation of the fragments by PFGE revealed 21 unique types. Application of DR-PCR/RFLP resulted in recognition of 12 clusters. The results showed that the DR-PCR/RFLP method is less discriminatory than REA-PFGE, however, the novel genotyping method can be used as an alternative technique for generating DNA profiles in epidemiological studies of intra-species genetic relatedness of Acinetobacter baumannii strains.

  4. A new trilocus sequence-based multiplex-PCR to detect major Acinetobacter baumannii clones.

    Science.gov (United States)

    Martins, Natacha; Picão, Renata Cristina; Cerqueira-Alves, Morgana; Uehara, Aline; Barbosa, Lívia Carvalho; Riley, Lee W; Moreira, Beatriz Meurer

    2016-08-01

    A collection of 163 Acinetobacter baumannii isolates detected in a large Brazilian hospital, was potentially related with the dissemination of four clonal complexes (CC): 113/79, 103/15, 109/1 and 110/25, defined by University of Oxford/Institut Pasteur multilocus sequence typing (MLST) schemes. The urge of a simple multiplex-PCR scheme to specify these clones has motivated the present study. The established trilocus sequence-based typing (3LST, for ompA, csuE and blaOXA-51-like genes) multiplex-PCR rapidly identifies international clones I (CC109/1), II (CC118/2) and III (CC187/3). Thus, the system detects only one (CC109/1) out of four main CC in Brazil. We aimed to develop an alternative multiplex-PCR scheme to detect these clones, known to be present additionally in Africa, Asia, Europe, USA and South America. MLST, performed in the present study to complement typing our whole collection of isolates, confirmed that all isolates belonged to the same four CC detected previously. When typed by 3LST-based multiplex-PCR, only 12% of the 163 isolates were classified into groups. By comparative sequence analysis of ompA, csuE and blaOXA-51-like genes, a set of eight primers was designed for an alternative multiplex-PCR to distinguish the five CC 113/79, 103/15, 109/1, 110/25 and 118/2. Study isolates and one CC118/2 isolate were blind-tested with the new alternative PCR scheme; all were correctly clustered in groups of the corresponding CC. The new multiplex-PCR, with the advantage of fitting in a single reaction, detects five leading A. baumannii clones and could help preventing the spread in healthcare settings.

  5. 鲍曼不动杆菌耐药性及碳青霉烯酶检测%The detection of Carbapenemase and resistance of Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    王中新; 李春; 沈继录

    2011-01-01

    目的 了解临床分离鲍曼不动杆菌对临床常用抗菌药物的耐药性及其产碳青霉烯酶情况,为临床抗感染治疗提供依据.方法 采用MicmScan WalkAway-40全自动微生物分析仪对240株临床分离的鲍曼不动杆菌进行鉴定和药敏试验,改良的Hodge试验检测耐碳青霉烯类鲍曼不动杆菌产生的碳青霉烯酶,并采用SPSS 13.0软件进行统计分析.结果 240株鲍曼不动杆菌对亚胺培南的耐药率最低(20.8%),对青霉素类、头孢菌素类、喹诺酮类、复方新诺明的耐药率均大于50%;耐碳青霉烯类鲍曼不动杆菌碳青霉烯酶的检出率为64.0%.结论 临床分离鲍曼不动杆菌耐药情况严重,碳青霉烯酶是鲍曼不动杆菌对碳青霉烯类抗菌药物耐药的主要原因.%Objective To investigate the resistance of Acinetobacter baumannii to antibiotics and Carbapenemase production of Carbapenem-resistant Acinetobacter baumannii and provide evidence for the clinical therapy of infections.Method The MicroScan WalkAway-40 system was used for identification and antibiotics susceptibility tests of 240 clinical isolated Acinetobacter baumannii; Hodge test was used to screen carbapenemases; SPSS 13.0 was used to perform the statistical analysis.Result The resistance rate of 240 Acinetobacter baumannii to Imipenem was the lowest (20.8%), and the resistant rates to Penicillin, Cephalcsporins, Quinolones and Sulfamethoxazolum-Trimethoprimum were more than 50%.Carbapenemase detection rate of Carbapenem resistant Acinetobacter baumannii was 61.7%.Conclusion The resistance of clinically isolated Acinetobacter baumannii is serious.Carbapenemase is the reason of the resistance of Acinetobacter baumannii to Carbapenem.

  6. 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.

  7. 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

  8. Emergence of rifampicin, tigecycline, and colistin-resistant Acinetobacter baumannii in Iran; spreading of MDR strains of novel International Clone variants.

    Science.gov (United States)

    Bahador, Abbas; Taheri, Mohammad; Pourakbari, Babak; Hashemizadeh, Zahra; Rostami, Hossein; Mansoori, Noormohamad; Raoofian, Reza

    2013-10-01

    Multidrug-resistant Acinetobacter baumannii infections are serious challenges for clinicians because of A. baumannii propensity to acquire resistance to a wide spectrum of antimicrobial agents. In this study, 91 A. baumannii isolates from patients in tertiary intensive care units of three university hospitals in the north, central, and south of Iran were selected and tested for susceptibility to 22 antimicrobials; amplified restriction fragment polymorphism and multiplex polymerase chain reaction methods were used to determine genetic relationships and International Clone (IC) of A. baumannii isolates, respectively. Twenty-four genotypes were identified in A. baumannii isolates. About 91.2% of isolates categorized into 4 distinct clusters; one was more heterogeneous and observed across the three locations. A considerable number of the isolates (27.5%) belonged to the novel IC variant, sequence group 7 (SG7), which was geographically widespread in three locations. The drug resistance pattern showed that 14.2%, 20%, and 77% of the A. baumannii isolates were resistant to colistin, tigecycline, and rifampicin, respectively. Nine percent of isolates (8) showed simultaneous resistance to colistin, rifampicin, and tigecycline. Interestingly, all of them were susceptible to ampicillin-sulbactam and/or tobramycin. According to our results, SG7 could be considered as a pan-Iranian clone.

  9. Antimicrobial photodynamic therapy in a mouse model of Acinetobacter baumannii burn infection

    Science.gov (United States)

    Dai, Tianhong; Tegos, George P.; Lu, Zongshun; Zhiyentayev, Timur; Huang, Liyi; Franklin, Michael J.; Baer, David G.; Hamblin, Michael R.

    2009-06-01

    Multi-drug resistant Acinetobacter baumanii infections represent a growing problem, especially in traumatic wounds and burns suffered by military personnel injured in Middle Eastern conflicts. Effective treatment using traditional antibiotics can be extremely difficult and new antimicrobial approaches are being investigated. One of these antimicrobial alternatives could be the combination of non-toxic photosensitizers (PS) and visible light known as photodynamic therapy (PDT). We report on the establishment of a new mouse model of full thickness thermal burns infected with a bioluminescent derivative of a clinical Iraqi isolate of A. baumannii and its PDT treatment by topical application of a PS produced by covalent conjugation chlorin(e6) to polyethylenimine followed by illumination of the burn surface with red light. Application of 108 A. baumannii cells to the surface of 10-second burns made on the dorsal surface of shaved female BALB/c mice led to chronic infections that lasted on average 22 days characterized by a remarkably stable bacterial bioluminescence. PDT carried out on day 0 soon after applying bacteria gave over three logs of loss of bacterial luminescence in a light exposure dependent manner, while PDT carried out on day 1 and day 2 gave approximately a 1.7-log reduction. Application of PS dissolved in 10% or 20% DMSO without light gave only modest reduction in bacterial luminescence from mouse burns. Some bacterial regrowth in the treated burn was observed but was generally modest. It was also found that PDT did not lead to inhibition of wound healing. The data suggest that PDT may be an effective new treatment for multi-drug resistant localized A. baumannii infections.

  10. 临床分离鲍曼不动杆菌生物被膜形成能力研究%Biofilm formation ability of clinically isolated acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    邹自英; 朱冰; 熊杰; 曾平; 汪璐; 吴艾霖; 陈莉

    2012-01-01

    Objective To study the biofilm formation ability of clinically isolated strains of acinetobacter baumannii (AB) in order to provide basis for the construction of AB biofilm detection platform and provide evidence for the prevention and control of hospital AB infection. Methods Semiquantitative crystal violet staining was used to detect the biofilm formation ability of AB isolated from clinical specimens. Results ( 1) Among 100 strains of AB, 81 ones had the ability of biofilm formation, in which the ability was weakly positive in 14 ones (17. 28% ) , positive in 21 ones (25. 93% ) and strongly positive in 46 ones (56. 79% ). The biofilm formation ability in other 19 strains was negative. (2) All AB isolated from different specimens had the ability of biofilm formation. (3) There was a negative correlation between the ability of bilfilm formation and drug resistance against antibacterials in vitro. Conclusion AB has strong ability of biofilm formation. Semiquantitative crystal violet staining is simple and convenient, which is a conventional method to detect biofilm formation ability of hospital AB infection.%目的 研究鲍曼不动杆菌(AB)临床分离菌株生物被膜形成能力,为医院感染AB生物被膜检测平台的建立奠定基础,为AB医院感染的预防和控制提供依据.方法 采用半定量结晶紫染色法,检测临床标本分离的AB生物被膜形成能力.结果 (1)100株AB中,81株具有生物被膜形成能力,其中形成能力弱阳性14株(17.28%),阳性21株(25.93%),强阳性46株(56.79%);另19株生物被膜形成检测试验阴性.(2)不同标本来源的AB均具有生物被膜形成能力.(3)AB生物被膜形成能力与体外抗菌药物耐药性呈负相关.结论 AB生物被膜形成能力较强.半定量结晶紫染色法简便易操作,无需特殊设备,可以作为监测医院感染AB生物被膜形成能力的常规方法.

  11. 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

  12. 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

  13. Clinical and microbiological characterization of carbapenem-resistant Acinetobacter baumannii bloodstream infections.

    Science.gov (United States)

    Song, Joon Young; Cheong, Hee Jin; Choi, Won Suk; Heo, Jung Yeon; Noh, Ji Yun; Kim, Woo Joo

    2011-05-01

    The incidence of carbapenem-resistant Acinetobacter baumannii infection is increasing, which might be associated with high morbidity and mortality among critically ill patients with limited therapeutic options. This study was conducted to evaluate the clinical and microbiological features of carbapenem-resistant A. baumannii bacteraemia. The medical records of 28 adult patients with this bacteraemia admitted to Korea University Guro Hospital, from January 2005 through December 2010, were reviewed. Using the 28 bloodstream isolates, we intended to detect genes encoding carbapenemases, and investigate the inoculum effect on each of the antimicrobial agents rifampicin, imipenem, colistin and tigecycline. With one blood isolate from a patient with pneumonia, rifampicin-inducible resistance was examined using the experimental mouse pneumonia model. Out of 28 carbapenem-resistant A. baumannii bloodstream infections (BIs), the most common primary focus was the central venous catheter (35.7 %) and then the lung (32.1 %). The 30 day overall mortality was 53.6 %; in most cases (80 %) the patients died within 10 days after the onset of the bacteraemia. By univariate analysis, inappropriate antimicrobial therapy (73.3 vs 30.8 %, P = 0.02), mechanical ventilation (53.3 vs 15.4 %, P = 0.04) and a high Pitt bacteraemia score (4.9±1.9 vs 2.2±1.2, P<0.01) were statistically significant risk factors for mortality, while only a high Pitt bacteraemia score (odds ratio 2.6; 95 % confidence interval 1.1-6.5) was independently associated with 30 day mortality by multivariate analysis. All 28 isolates had the bla(OXA-51)-like gene with upstream ISAbaI, 2 of which additionally had the bla(OXA-58)-like gene and the bla(OXA-23)-like gene. Inoculum effect and rifampicin inducible resistance were not detected. Considering the rapid progression to death in carbapenem-resistant A. baumannii BIs, early empirical antibiotic therapy would be warranted based on the local

  14. 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.

  15. Role of fibronectin in the adhesion of Acinetobacter baumannii to host cells.

    Directory of Open Access Journals (Sweden)

    Younes Smani

    Full Text Available Adhesion to host cells is an initial and important step in Acinetobacter baumannii pathogenesis. However, there is relatively little information on the mechanisms by which A. baumannii binds to and interacts with host cells. Adherence to extracellular matrix proteins, such as fibronectin, affords pathogens with a mechanism to invade epithelial cells. Here, we found that A. baumannii adheres more avidly to immobilized fibronectin than to control protein. Free fibronectin used as a competitor resulted in dose-dependent decreased binding of A. baumannii to fibronectin. Three outer membrane preparations (OMPs were identified as fibronectin binding proteins (FBPs: OMPA, TonB-dependent copper receptor, and 34 kDa OMP. Moreover, we demonstrated that fibronectin inhibition and neutralization by specific antibody prevented significantly the adhesion of A. baumannii to human lung epithelial cells (A549 cells. Similarly, A. baumannii OMPA neutralization by specific antibody decreased significantly the adhesion of A. baumannii to A549 cells. These data indicate that FBPs are key adhesins that mediate binding of A. baumannii to human lung epithelial cells through interaction with fibronectin on the surface of these host cells.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Drug resistance analysis on 694 strains of Acinetobacter baumannii%694株鲍曼不动杆菌的耐药性分析

    Institute of Scientific and Technical Information of China (English)

    官琳妹; 蔡溢; 孙悦波

    2012-01-01

    目的 了解大连市友谊医院临床分离的鲍曼不动杆菌的分布及耐药状况,为临床治疗鲍曼不动杆菌感染提供参考.方法 对该院2007年至2009年住院患者送检的标本中分离到的694株鲍曼不动杆菌的分布及药敏结果做回顾性分析.结果 鲍曼不动杆菌2007年检出112株(7.1%),2008年检出210(11.3%)株,2009年检出372(14.7%)株;在所有临床送检的标本中,痰标本中的检出率最高,占88.7%;在对13种抗生素的药敏试验中,对美罗培南最为敏感,其次对头孢哌酮/舒巴坦较为敏感.结论 鲍曼不动杆菌的检出率逐年增高,耐药率也逐年增高.%Objective To understand the clinical distribution and drug resistance characteristics of Acinetobacter baumannii in Dalian Municipal Friendship Hospital in order to provide reference for the clinical treatment of Acinetobacter baumannii infection. Method A retrospective statistical analysis was performed on the clinical distribution and drug resistance results of 694 Acinetobacter baumannii isolated from inpatient samples between 2007 and 2009. Result 112 strains of Acinetobacter baumannii (7.1% ) were detected in 2007, 210 strains (11.3% ) in 2008, and 372 strains in 2009. Detection rate of Acinetobacter baumannii was 88.7% in sputum specimens, which was the highest among all kinds of specimens. 13 kinds of antibiotics were used in antibiotic susceptibility test. The sensitivity of Acinetobacter baumannii to meropenemin was the highest, followed by cefoperazone/sulbactam. Conclusion Detection rate of Acinetobacter baumannii is increasing year by year, so is its drug resistance rate.

  19. ANALYSIS OF INFECTION DISTRIBUTION AND DRUG RESISTANCE OF ACINETOBACTER BAUMANNII%鲍曼不动杆菌感染分布及耐药性分析

    Institute of Scientific and Technical Information of China (English)

    燕成岭; 樊淑珍

    2014-01-01

    目的:了解我院鲍曼不动杆菌的感染分布与耐药情况,为临床治疗提供依据。方法:对住院病人送检样本中培养分离出的825株鲍曼不动杆菌的感染分布与耐药情况进行分析。采用稀释法进行药物敏感试验,结果按CLSI标准判定。结果:鲍曼不动杆菌主要分布在重症监护病房( ICU )和呼吸科,主要来自痰标本(90.6%),对丁胺卡那霉素的耐药率最低(16.28%),其次为亚胺培南(31.25%),对其他19种抗菌药物的耐药率均较高。结论:鲍曼不动杆菌主要引起呼吸道感染,对现有多种抗菌药物耐药严重,提示临床医师必须对该菌所致感染予以高度重视。%Objective:To investigate the clinical distribution and drug resistance of Acinetobacter baumannii in order to offer basis for the clinical therapeutics. Methods:Analyze the infection distribution and drug resistance of 825 samples of Acinetobacter baumannii that were isolated from various kinds of specimens from inpatients. The drug sensitivity test was done by means of dilution,and then the results were assessed with CLSI ( Clinical and Laboratory Standards Institute ) . Results:Acinetobacter baumannii samples were mainly distributed in ICU ward and Respiration department. The highest positive rate of Acinetobacter baumannii was in sputum ( 90 . 6%) . The resistance rates to Amikacin(16.28%). were the lowest,and to Imipenem(31.25%)came to be next. Acinetobacter baumannii were high resistant to other 19 tested antibiotics. Conclusions:Acinetobacter baumannii is a common pathogen of respiratory tract infection,which has a high resistance rate to the current clinical antibacterial agents. Consequently, clinical doctors should attach more importance to the infection resulted from Acinetobacter Baumannii.

  20. The comparison of genotyping, antibiogram, and antimicrobial resistance genes between carbapenem-susceptible and -resistant Acinetobacter baumannii.

    Science.gov (United States)

    Chen, Chih-Ming; Ke, Se-Chin; Li, Chia-Ru; Chang, Chao-Chin

    2014-12-01

    This study was conducted to explore the epidemiological and molecular differences between carbapenem-susceptible Acinetobacter baumannii (CSAB) and carbapenem-resistant A. baumannii (CRAB) isolates. Thirty-two CSAB and 55 CRAB isolates were collected in 2010. By multilocus sequence typing analysis, 31 (56%) CRAB isolates and 11 (34%) CSAB isolates belonged to ST2. Twenty-one (38%) CRAB isolates, and 4 (13%) CSAB isolates belonged to a new type, ST129. The blaIMP, blaVIM, and blaOXA-58-like were not detected in our study isolates. blaOXA-23 and blaOXA-24/40-like were not detected in all CSAB isolates. On the contrary, blaOXA-23 was detected in 51 (93%) CRAB isolates. Class 1 integron was detected in 19 (35%) CRAB isolates and 8 (25%) CSAB isolates (p>0.05). In conclusion, the ST2 and ST129 were the major sequence types in both CSAB and CRAB isolates. The blaOXA-23 is the primary carbapenem-resistance gene in CRAB isolates from hospitalized patients and the specimens collected from hospital environment.

  1. Isolation and Identification of One Strain of Acinetobacter baumannii in Infected Beef Cattle%1株感染肉牛的鲍氏不动杆菌的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    李能章; 邱荣蓉; 牛娟; 胡娟; 周伟; 彭远义

    2012-01-01

    [Objective]The research aimed to separate and identify the pathogens from beef cattle infected with mycoplasma pneumonia. [ Meth-od ] The pathogens were separated from the lung tissue of diseased cattle with mycoplasma pneumonia in a cattle farm where bovine mycoplasma pneumonia outbroke. And the pathogenicity detection and drug - sensitivity test were made on the isolated bacteria. And the pathogens were identified by the sequencing of 16S rDNA and phylogenetic analysis. [Result] FC - 1 strain was isolated along with Mycoplasma bovis. FC - 1 strain was a Gram - negative coccobacillus, with the drug - resistance to macrolides antibiotics and sensitivity to a minoglycosides and quinolones. 16S rDNA sequencing results showed that strain FC -1 belonged to the species Acinetobacter baumannii. [ Conclusion] The pathogens that caused bovine mycoplasma pneumonia might have the mixed infection with other pathogens except Mycoplasma bovis.%[目的]从疑似患有支原体肺炎肉牛中分离出致病茵,并对其进行鉴定.[方法]从爆发牛支原体肺炎的某牛场病牛肺组织中分离致病茵,并对其进行致病性检测和药敏试验.通过16S rDNA序列测定与系统进化分析,进行病原茵的鉴定.[结果]除分离到牛支原体外,还分离到1株致病性细菌FC-1.该茵革兰氏染色为阴性,球杆状,对大环内酯类药物具有耐药性,对氨基糖苷类及喹诺酮类抗生素敏感.16S rDNA序列测定结果表明该茵为1株鲍氏不动杆菌.[结论]导致牛支原体肺炎的病原除牛支原体外,还可能存在其他病原的混合感染.

  2. 泛耐药鲍曼不动杆菌的研究进展%Research advances on extensive-drug resistant Acinetobacter baumannii

    Institute of Scientific and Technical Information of China (English)

    孔海芳; 胡志东

    2015-01-01

    With the wide application of antibiotics,Acinetobacter baumannii infection has increased gradually.The clinical isolating rates of multidrug resistant (MDR),extensive-drug resistant (XDR) and even pandrug resistant (PDR) A.baumannii increase significantly.A.baumannii has become an important opportunistic pathogen in the nosocomial setting.The article reviews the resistance mechanism and therapeutic options of the extensive-drug resistant A.Baumannii.%随着抗生素的广泛应用,鲍曼不动杆菌的感染日趋上升,多重耐药、泛耐药、甚至全耐药鲍曼不动杆菌分离率明显增加,成为院内感染的重要条件致病菌.此文就泛耐药鲍曼不动杆菌的耐药机制以及治疗药物作一综述.

  3. 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.

  4. 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.

  5. 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.

  6. Analysis on the isolation rate and the trend of drug resistance of Acinetobacter Baumannii in our hospital from 2010 to 2012%我院2010年-2012年鲍曼不动杆菌检出率及耐药趋势分析

    Institute of Scientific and Technical Information of China (English)

    陈涛; 李阳敏; 宗安辉

    2014-01-01

    Objective In order to monitor the hospital infection and provide the basis for rational drug use,we monitored the detection rate and drug resistance of Acinetobacter Baumannii and pan-resistant Acinetobacter Baumannii isolated from clinical specimens in our hospital from 2010 to 2012. Methods Various infections specimens of patients in our hospital in the past three years were collected and isolated. Then, the Bacterial strainidentification and the minimum inhibitory concentration (MIC) were carried out by America DADE-MicroScan Neg Combo Type 31. At the same time, the MIC was repeatedlydetected using Agar disk diffusion (K-B) method as supplement. All data were analyzed statistically by WHONET5.6 software for excluding repetitive strain. Result In 2010 ~2012 Bauman Acinetobacter infection rates were 9.18%,6.92%,and 7.19%. The detection rates of pan drug resistant (XDR) Acinetobacter baumannii were 12.41%,26.47%,and 13.01%.Conclusion Since 2012,although we have strengthened the hospital infection control and the management of the rational use of antibiotics,Acinetobacter baumannii resistance rates showed an upward trend with the detecting rate ofpan drug resistant Acinetobacter Baumannii reducing.%目的:监测我院2010年-2012年从临床标本中分离的鲍曼不动杆菌及泛耐药鲍曼不动杆菌的检出率及对抗菌药物的耐药情况,为医院感染监测和临床合理用药提供依据。方法收集近3年来我院患者的各类感染标本,经微生物室培养后,用美国DADE-MicroScan Neg Combo Type 31细菌菌种鉴定和最低抑菌浓度(MIC)测定,补充药敏试验用琼脂纸片扩散(K-B)法进行检测。所有数据通过WHONET5.6软件进行统计学分析,以排除重复菌株。结果2010年-2012年鲍曼不动杆菌的检出率分别为9.18%,6.92%,7.19%,其中泛耐药(XDR)鲍曼不动杆菌在所分离出的鲍曼不动杆菌中的检出率分别为12.41%,26.47%,13.01%。结论自2012年我院

  7. Biosurfactant and enzyme mediated crude oil degradation by Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3

    National Research Council Canada - National Science Library

    Parthipan, Punniyakotti; Elumalai, Punniyakotti; Sathishkumar, Kuppusamy; Sabarinathan, Devaraj; Murugan, Kadarkarai; Benelli, Giovanni; Rajasekar, Aruliah

    2017-01-01

    The present study focuses on the optimization of biosurfactant (BS) production using two potential biosurfactant producer Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3 and role of enzymes in the biodegradation of crude oil...

  8. Characterization of surface antigen protein 1 (SurA1) from Acinetobacter baumannii and its role in virulence and fitness.

    Science.gov (United States)

    Liu, Dong; Liu, Zeng-Shan; Hu, Pan; Cai, Ling; Fu, Bao-Quan; Li, Yan-Song; Lu, Shi-Ying; Liu, Nan-Nan; Ma, Xiao-Long; Chi, Dan; Chang, Jiang; Shui, Yi-Ming; Li, Zhao-Hui; Ahmad, Waqas; Zhou, Yu; Ren, Hong-Lin

    2016-04-15

    Acinetobacter baumannii is a Gram-negative bacillus that causes nosocomial infections, such as bacteremia, pneumonia, and meningitis and urinary tract and wound infections. In the present study, the surface antigen protein 1 (SurA1) gene of A. baumannii strain CCGGD201101 was identified, cloned and expressed, and then its roles in fitness and virulence were investigated. Virulence was observed in the human lung cancer cell lines A549 and HEp-2 at one week after treatment with recombinant SurA1. One isogenic SurA1 knock-out strain, GR0015, which was derived from the A. baumannii strain CCGGD201101 isolated from diseased chicks in a previous study, highlighted the effect of SurA1 on fitness and growth. Its growth rate in LB broth and killing activity in human sera were significantly decreased compared with strain CCGGD201101. In the Galleria mellonella insect model, the isogenic SurA1 knock-out strain exhibited a lower survival rate and decreased dissemination. These results suggest that SurA1 plays an important role in the fitness and virulence of A. baumannii.

  9. Correlation Between ISAba1 Upstream ampC Gene and Resistance to Cefotaxime in Acinetobacter baumannii: A Serious Threat to Nosocomial Infections

    Directory of Open Access Journals (Sweden)

    Rezaee

    2016-01-01

    Full Text Available Background Infections due to Acinetobacter baumannii have become a significant challenge in modern healthcare systems. The global upsurge of multidrug resistance in A. baumannii has created widespread problems in the treatment of patients. Objectives We examined the prevalence ISAmpC and its correlation with cefotaxime resistance. Materials and Methods Standard biochemical tests were used to identify isolates. Genomic species of the genus Acinetobacter were confirmed by Amplified Ribosomal DNA Restriction Analysis (ARDRA. The susceptibility of 50 A. baumannii isolates to a variety of antimicrobial agents was determined using the disk diffusion method and E-test strips. PCR was used to investigate the connection of insertion sequences and the ampC gene. Clonal relatedness was determined by Repetitive Extragenic Palindromic PCR. Results ISAba1 located upstream of blaampC was found in 24 (48% of the A. baumannii isolates. In all of the studied isolates that had ISAmpC, the MIC for cefotaxime was 64 - 256 μg/mL. Based on the REP-PCR patterns among the resistant isolates, the highest number of ISAmpC positive isolates belonged to type B (n = 19 and type C (n = 12. Conclusions ISAba1 has become an important factor in A. baumannii’s resistance to cefotaxime.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. OXA-23 carbapenemase in multidrug-resistant Acinetobacter baumannii ST2 type: first identification in L'Aquila Hospital (Italy).

    Science.gov (United States)

    Perilli, Mariagrazia; Sabatini, Alessia; Pontieri, Eugenio; Celenza, Giuseppe; Segatore, Bernardetta; Bottoni, Carlo; Bellio, Pierangelo; Mancini, Alisia; Marcoccia, Francesca; Brisdelli, Fabrizia; Amicosante, Gianfranco

    2015-02-01

    In this study 114 extensively drug-resistant Acinetobacter baumannii clinical isolates were characterized. The strains were collected at L'Aquila Hospital after the earthquake in L'Aquila city (central Italy) on the 6th of April 2009. The genes blaOXA-23 and blaOXA-51 were detected in all clinical isolates analyzed, whereas blaTEM-1 allele was detected in 56/114 isolates. The blaOXA-23 gene is located downstream the ISAba region and is under control of a strong promoter. On 42/80 A. baumannii the presence of two class 1 integrons was ascertained on chromosomal DNA. Variable regions show different gene array: (1) aadB and aadA2, (2) aacA4, aac(6')-Ib-cr, and aadA1. Macrorestriction analysis using ApaI restriction endonuclease identifies three clusters (A, B, and C) according to pulsed-field gel electrophoresis profiles. All isolates analyzed belong to the clone A. baumannii sequence type 2.

  12. Molecular characterisation of antimicrobial resistance in Pseudomonas aeruginosa and Acinetobacter baumannii during 2014 and 2015 collected across India

    Directory of Open Access Journals (Sweden)

    A K Pragasam

    2016-01-01

    Full Text Available Background: Surveillance of antimicrobial resistance (AMR is of great importance. Pseudomonas aeruginosa and Acinetobacter baumannii are important pathogens and emergence of resistance in these have increased the morbidity and mortality rates. This surveillance study was initiated by the Government of India - Indian Council of Medical Research. The aim of this study is to determine the antimicrobial susceptibility profile and to characterise the enzyme mediated antimicrobial resistance such as extended spectrum beta-lactamases (ESBLs and carbapenemases among multidrug-resistant (MDR P. aeruginosa and A. baumannii. Materials and Methods: A multi-centric study was conducted from January 2014 to December 2015 with a total number of 240 MDR P. aeruginosa and 312 MDR A. baumannii isolated from blood, cerebrospinal fluid, respiratory, pus, urine and intra-abdominal infections. Kirby–Bauer disc diffusion was done to determine the antimicrobial susceptibility profile. Further, MDR isolates were characterised by multiplex polymerase chain reaction to determine the resistance genes for ESBLs and carbapenemases. Results: Among the ESBLs, blaVEB (23%, blaTEM (5% and blaSHV (0.4% in P. aeruginosa and blaPER (54%, blaTEM (16% and blaSHV (1% in A. baumannii were the most prevalent. Likewise, blaVIM (37%, blaNDM (14%, blaGES (8% and blaIMP (2% in P. aeruginosa and blaOXA-23like (98%, blaOXA-58like (2%, blaNDM (22% and blaVIM (3% in A. baumannii were found to be the most prevalent carbapenemases. blaOXA-51like gene, intrinsic to A. baumannii was present in all the isolates tested. Conclusion: The data shown highlight the wide difference in the molecular mechanisms of AMR profile between P. aeruginosa and A. baumannii. In P. aeruginosa, plasmid-mediated mechanisms are much lesser than the chromosomal mediated mechanisms. In A. baumannii, class D oxacillinases are more common than other mechanisms. Continuous surveillance to monitor the trends in AMR among MDR

  13. Genotyping of Carbapenem-resistant Acinetobacter Baumannii Strains Isolated from Intensive Care Units%重症监护室耐碳青酶烯类鲍曼不动杆菌的基因分型

    Institute of Scientific and Technical Information of China (English)

    郑培烝; 邹红; 傅芬蕊; 潘玉红; 黄心宏; 曹颖平

    2014-01-01

    目的:了解笔者医院重症监护室(ICU)分离的耐碳青霉烯类鲍曼不动杆菌(CRAB)的分子流行病学特点。方法收集2010年9月-2012年3月ICU分离的CRAB共34株,其中综合ICU 25株,烧伤ICU 9株,采用基于rep-PCR原理的DiversiLab系统进行基因分型分析。结果34株CRAB共分A、B、C和D 4型,烧伤IC U中存在A和D型,以A型为主且A型仅出现在烧伤IC U ;综合IC U中存在B ,C和D型,以D型为主且B和C型仅出现在综合ICU。结论烧伤ICU和综合ICU 中流行的CRAB基因型不同。D型CRAB同时存在两个IC U中提示IC U间可能存在交叉感染。%Objective To investigate the molecular epidemiology of carbapenem-resistant Acineto-bacter baumannii(CRAB) strains collected from intensive care units (ICUs) in our hospital . Methods 34 CRAB strains were collected and isolated at ICUs of our hospital during the period of September 2010 to April 2012 ,of which 25 from general ICU ,and 9 from Burn ICU . Genotyping was performed by Diversi-lab repetitive element PCR system . Results There were 4 types of CRAB strains ,including type A ,B , C and D . Type A and D CRAB strains existed in Burn ICU Type A dominated . Type B ,C and D CRAB strains were found in general ICU with Type D dominant . Conclusion The epidemic strains of CRAB in Burn ICU was different from that in general ICU ,and the type D CRAB strain appeared simultaneously in both the ICUs suggesting that a cross infection may prevail in the two ICUs .

  14. Spread of carbapenem-resistant international clones of Acinetobacter baumannii in Turkey and Azerbaijan: a collaborative study.

    Science.gov (United States)

    Ahmed, S S; Alp, E; Ulu-Kilic, A; Dinc, G; Aktas, Z; Ada, B; Bagirova, F; Baran, I; Ersoy, Y; Esen, S; Guven, T G; Hopman, J; Hosoglu, S; Koksal, F; Parlak, E; Yalcin, A N; Yilmaz, G; Voss, A; Melchers, W

    2016-09-01

    Epidemic clones of Acinetobacter baumannii, described as European clones I, II, and III, are associated with hospital epidemics throughout the world. We aimed to determine the molecular characteristics and genetic diversity between European clones I, II, and III from Turkey and Azerbaijan. In this study, a total of 112 bloodstream isolates of carbapenem-resistant Acinetobacter spp. were collected from 11 hospitals across Turkey and Azerbaij