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

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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. © 2012 The Authors. Clinical Microbiology and Infection © 2012 European Society of

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

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Zhu, Lingxiang; Yan, Zhongqiang; Zhang, Zhaojun; Zhou, Qiming; Zhou, Jinchun; Wakeland, Edward K; Fang, Xiangdong; Xuan, Zhenyu; Shen, Dingxia; Li, Quan-Zhen

2013-01-01

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. 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. Our comparative analysis on currently completed Acinetobacter baumannii

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

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Lingxiang Zhu

Full Text Available 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.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.Our comparative analysis on currently completed

Determination antimicrobial resistance profile of Acinetobacter strains isolated from hospitalized patients in Different Part of Taleghani Hospital (Ahvaz, Iran

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Khadijah Ahmadi

2014-10-01

Full Text Available Background: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections such as meningitis, endocarditis, skin and soft tissue infections, urinary tract infection, conjunctivitis, burn wound infection and bacteremia. This organism has been shown resistance to different antimicrobial agents. The aim of this study was to determination antibiotic resistance profile of Acinetobacter strains isolated from hospitalized patients in Taleghani hospital (Ahvaz, Iran. Materials and Methods: This cross-sectional study was conducted on 43 Acinetobacter strains isolated from hospitalized patients. Clinical specimens were cultured on microbiological media. Subsequently, drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Results: Acinetobacter strains were isolated from different specimens consisting biopsy 24 (55.8%, wound 13 (30/2% and blood 6 (14%. In antimicrobial susceptibility testing, colistin exhibited the greatest activity (60.5% against isolated strains. 33 (76/7% isolates demonstrated resistance to imipenem. Conclusion: In outbreak situations, surveillance cultures of patients involved in the outbreak or who are deemed at risk for colonization/infection with the outbreak organism are often parts of the planned intervention.

Pan Drug-Resistant Environmental Isolate of Acinetobacter baumannii from Croatia.

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Goic-Barisic, Ivana; Seruga Music, Martina; Kovacic, Ana; Tonkic, Marija; Hrenovic, Jasna

2017-06-01

Acinetobacter baumannii is an emerging nosocomial pathogen with also emerging resistance to different antibiotics. Multidrug and pan drug-resistant clinical isolates were reported worldwide. Here we report the first evidence of pan drug-resistant environmental isolate of A. baumannii. The isolate was recovered from the effluent of secondary treated municipal wastewater of the City of Zagreb, Croatia. The isolate was resistant to penicillins/β-lactamase inhibitors, carbapenems, fluoroquinolones, aminoglycosides, folate pathway inhibitors, and polymyxins, except intermediately susceptible to minocycline and tigecycline. Intrinsic chromosomally located bla OXA-51-like gene and acquired plasmid-located bla OXA-23-like gene were related to clinical isolates. Pan drug-resistant A. baumannii can occur in natural environments outside of the hospital. Secondary treated municipal wastewater represents a potential epidemiological reservoir of pan drug-resistant A. baumannii and carbapenem resistance gene.

Studying the Relationship between the Ability of Biofilm Formation and Antibiotic Resistance in Acinetobacter baumannii Clinical and Environmental Isolates in Tehran, 2015

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Faegheh Teymori

2017-07-01

Full Text Available Abstract Background: Acinetobacters are aerobic gram-negative bacteria which are distributed widespread in soil and water. The bacteria are isolated from cultured skin, mucous membranes, secretions and hospital environment. Acinetobacter baumannii, is a strain that more frequently isolated. Acinetobacter strains are often resistant against antimicrobial agents. Materials and Methods: The method of this study was based on field, observation and test. On August and October 2015, samples were isolated from the soil and water of the Sadeghieh Square river in Tehran, respectively, and were transferred to the laboratory in the ice pack. 50 baumannii samples were isolated by biochemical methods (TSI, SIM, OF and gram test. November 1394, 100 clinical samples were isolated from Imam Khomeini hospital by biochemical method, and in the culture media Mueller Hinton agar plates were transferred to the laboratory. Antibiogram test for 150 baumannii samples was performed. Biofilms formation of Acinetobacter baumannii environmental and clinical samples was investigated by Congo red agar and culture plate methods. Results: In all samples (clinical and soil, most of antibiotic resistance was 92% for imipenem and the resistance of water samples to imipenem was 99.9%. Biofilm formation by Congo red agar in water, soil, and clinical samles was resprctively 44%, 40% and 1%. All isolates were negative biofilm culture plate. Conclusion: Considering Acinetobacter baumannii resistance to antibiotics and the lack of biofilm formation of in clinical and environmental isolates, it was concluded that there wasn’t any relationship between antibiotic resistance and biofilm formation.

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

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

2015-07-01

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

Nosocomial infections due to Acinetobacter calcoaceticus.

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Zaer F

1989-01-01

Full Text Available Fifty four isolates of Acinetobacter calcoaceticus were studied in a period of 6 months. Maximum isolates were from burns cases and environmental sampling from burns ward also grew the same organism, indicating their role as nosocomial pathogen. Acinetobacter may initially be mistaken for Neisseria species. As the organisms show multidrug resistance to commonly used antibiotics their correct identification is important.

Nosocomial infections due to Acinetobacter calcoaceticus.

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Zaer, F; Deodhar, L

1989-01-01

Fifty four isolates of Acinetobacter calcoaceticus were studied in a period of 6 months. Maximum isolates were from burns cases and environmental sampling from burns ward also grew the same organism, indicating their role as nosocomial pathogen. Acinetobacter may initially be mistaken for Neisseria species. As the organisms show multidrug resistance to commonly used antibiotics their correct identification is important.

Use of Comparative Genomics To Characterize the Diversity of Acinetobacter baumannii Surveillance Isolates in a Health Care Institution

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Wallace, Lalena; Daugherty, Sean C.; Nagaraj, Sushma; Johnson, J. Kristie; Harris, Anthony D.

2016-01-01

Despite the increasing prevalence of the nosocomial pathogen Acinetobacter baumannii, little is known about which genomic components contribute to clinical presentation of this important pathogen. Most whole-genome comparisons of A. baumannii have focused on specific genomic regions associated with phenotypes in a limited number of genomes. In this work, we describe the results of a whole-genome comparative analysis of 254 surveillance isolates of Acinetobacter species, 203 of which were A. baumannii, isolated from perianal swabs and sputum samples collected as part of an infection control active surveillance program at the University of Maryland Medical Center. The collection of surveillance isolates includes both carbapenem-susceptible and -resistant isolates. Based on the whole-genome phylogeny, the A. baumannii isolates collected belong to two major phylogenomic lineages. Results from multilocus sequence typing indicated that one of the major phylogenetic groups of A. baumannii was comprised solely of strains from the international clonal lineage 2. The genomic content of the A. baumannii isolates was examined using large-scale BLAST score ratio analysis to identify genes that are associated with carbapenem-susceptible and -resistant isolates, as well as genes potentially associated with the source of isolation. This analysis revealed a number of genes that were exclusive or at greater frequency in each of these classifications. This study is the most comprehensive genomic comparison of Acinetobacter isolates from a surveillance study to date and provides important information that will contribute to our understanding of the success of A. baumannii as a human pathogen. PMID:27458211

UV light-induced survival response in a highly radiation-resistant isolate of the Moraxella-acinetobacter group

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Keller, L.C.; Thompson, T.L.; Maxcy, R.B.

1982-01-01

A highly radiation-resistant member of the Moraxella-Acinetobacter group, isolate 4, obtained from meat, was studied to determine the effect of preexposure to UV radiation on subsequent UV light resistance. Cultures that were preexposed to UV light and incubated for a short time in plate count broth exhibited increased survival of a UV light challenge dose. This response was inhibited in the presence of chloramphenicol. Frequencies of mutation to streptomycin, trimethoprim, and sulfanilamide resistance remained the same after the induction of this survival response and were not altered by treatment with mutagens, with the exception of mutation to streptomycin resistance after γ-irradiation or nitrosoguanidine or methyl methane sulfonate treatment. The results indicated that isolate 4 has a UV light-inducible UV light resistance mechanism which is not associated with increased mutagenesis. The characteristics of the radiation resistance response in this organism are similar to those of certain other common food contaminants. Therefore, considered as part of the total microflora of meat, isolate 4 and the other radiation-resistant Moraxella-Acinetobacter isolates should not pose unique problems in a proposed radappertizaton process

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

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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.

Isolation and Whole-genome Sequence Analysis of the Imipenem Heteroresistant Acinetobacter baumannii Clinical Isolate HRAB-85.

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Li, Puyuan; Huang, Yong; Yu, Lan; Liu, Yannan; Niu, Wenkai; Zou, Dayang; Liu, Huiying; Zheng, Jing; Yin, Xiuyun; Yuan, Jing; Yuan, Xin; Bai, Changqing

2017-09-01

Heteroresistance is a phenomenon in which there are various responses to antibiotics from bacterial cells within the same population. Here, we isolated and characterised an imipenem heteroresistant Acinetobacter baumannii strain (HRAB-85). The genome of strain HRAB-85 was completely sequenced and analysed to understand its antibiotic resistance mechanisms. Population analysis and multilocus sequence typing were performed. Subpopulations grew in the presence of imipenem at concentrations of up to 64μg/mL, and the strain was found to belong to ST208. The total length of strain HRAB-85 was 4,098,585bp with a GC content of 39.98%. The genome harboured at least four insertion sequences: the common ISAba1, ISAba22, ISAba24, and newly reported ISAba26. Additionally, 19 antibiotic-resistance genes against eight classes of antimicrobial agents were found, and 11 genomic islands (GIs) were identified. Among them, GI3, GI10, and GI11 contained many ISs and antibiotic-resistance determinants. The existence of imipenem heteroresistant phenotypes in A. baumannii was substantiated in this hospital, and imipenem pressure, which could induce imipenem-heteroresistant subpopulations, may select for highly resistant strains. The complete genome sequencing and bioinformatics analysis of HRAB-85 could improve our understanding of the epidemiology and resistance mechanisms of carbapenem-heteroresistant A. baumannii. Copyright © 2017. Published by Elsevier Ltd.

Enrichment of Acinetobacter spp. from food samples.

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

2016-05-01

Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p enrichment. Next, the Dijkshoorn's enrichment followed by direct plating on CHROMagar™ Acinetobacter was applied to detect Acinetobacter spp. in different foods. Fourteen different presumptive acinetobacters were recovered and assumed to represent nine different strains on the basis of REP-PCR typing. Eight of these strains were identified by rpoB gene analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecular characterization of Ambler class A to D β-lactamases, ISAba1, and integrons reveals multidrug-resistant Acinetobacter spp. isolates in northeastern China.

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Sun, Xiaoyu; Liu, Bin; Chen, Yan; Huang, Honglan; Wang, Guoqing; Li, Fan; Ni, Zhaohui

2016-12-01

The prevalence of various Ambler class A to D β-lactamases, ISAba1, and class 1 and 2 integrons as well as the clonal relatedness in 105 Acinetobacter spp. isolates found in northeastern China was investigated. All 105 Acinetobacter spp. isolates were determined to be multidrug resistant (MDR), and the resistance rates to carbapenem agents were approximately 50%. PER, IMP, AmpC, and OXA-23 were found to be dominant β-lactamases belonging to different classes, respectively. This is the first report of the coexistence of bla PER , bla IMP , bla AmpC , and bla OXA-23-like genes in Acinetobacter spp. isolates from northeastern China. ISAba1 was found upstream of the bla OXA-23-like gene in 87.8% (36/41) strains and upstream of the bla OXA-51-like gene in 26.5% (13/49) strains. ISAba3-like element was found upstream of the bla OXA-58-like gene in one bla OXA-58-like -positive strain. The presence of IntI1 was detected in 63.8% (67/105) of the isolates and the most prevalent gene cassettes were aacA4, aadA1, and catB8. The highly prevalent isolates belong to international clonal lineage (ICL)-II. These results indicate that the wide horizontal and clonal spread of MDR Acinetobacter spp. isolates harbouring multiple β-lactamase genes has become a serious problem in northeastern China.

Isolation of a bacterial strain, Acinetobacter sp. from centrate wastewater and study of its cooperation with algae in nutrients removal.

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Liu, Hui; Lu, Qian; Wang, Qin; Liu, Wen; Wei, Qian; Ren, Hongyan; Ming, Caibing; Min, Min; Chen, Paul; Ruan, Roger

2017-07-01

Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp. Removal efficiencies of some nutrients were improved significantly by the co-cultivation of algae and Acinetobacter sp. After treatment, residual nutrients in centrate wastewater reached the permissible discharge limit. The cooperation between algae and Acinetobacter sp. was in part attributed to the exchange of carbon dioxide and oxygen between the algae and bacteria. This synergetic relationship between algae and Acinetobacter sp. provided a promising way to treat the wastewater by improving the nutrients removal and biomass production. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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Dinesh M Fernando

2016-11-01

Full Text Available Acinetobacter baumannii, a Gram-negative opportunistic pathogen, is known to cause multidrug resistant infections. This organism has primarily been isolated from clinical environments and its environmental reservoirs remain largely unknown. In the present study, we recovered seven isolates of A. baumannii growing under conditions selective for Campylobacter spp. (microaerophilic at 42 oC and in the presence of antibiotics from dairy cattle manure storage tank or surface water impacted by livestock effluents. Antibiotic susceptibility tests revealed that all of these isolates were less susceptible to at least two different clinically relevant antibiotics, compared to the type strain A. baumannii ATCC17978. Expression of resistance-nodulation-division efflux pumps, an important mechanism of intrinsic resistance in these organisms, was analyzed and adeB was found to be overexpressed in one and adeJ was overexpressed in three isolates. Comparison of these isolates using genomic DNA Macro-Restriction Fragment Pattern Analysis (MRFPA revealed relatively low relatedness among themselves or with some of the clinical isolates from previous studies. This study suggests that A. baumannii isolates are capable of growing under selective conditions for Campylobacter spp. and that this organism can be present in manure and water.

Antimicrobial susceptibility pattern of acinetobacter species-one year experience in a tertiary care setting

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Qureshi, Z.A.; Abbasi, S.A.; Mirza, I.A.; Malik, N.; Sattar, A.

2012-01-01

Objective: To find out antimicrobial susceptibility pattern of Acinetobacter species isolated from 1 January 2009 through 31 December 2009 at Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi. Materials and Methods: A total of 276 isolates of Acinetobacter spp yielded from various clinical specimens during the study period were included Routine conventional methods were used to identify various species of Acinetobacter and modified Kirby-Bauer disk diffusion method was used for susceptibility testing. Out of total 276 isolates, 176 (63.8%) turned out to be Acinetobacter baumannii and 100 (36.2%) were Acinetobacter johnsonii. Overall sensitivity of Acinetobacter spp against piperacillin/sulbactam, tigecycline, sulbactam/cefoperazone, piperacillin/tazobactam, imipenem, doxycycline, ceftazidime, ciprofloxacin, chloramphenicol, trimethoprim /sulfamethoxazole, ampicillin, gentamycin, ceftriaxone, amoxicillin/clavulanic acid and ampicillin were 64%,63%, 48%, 47%, 41%,39%,35%, 34%, 32%, 31 %, 29%, 19%, 18% and 5% respectively. Out of 276 isolates, 181 (66 %) were multidrug resistant while 33 (18 %) isolates were pan-drug resistant. (author)

Propolis as an antibacterial agent against clinical isolates of mdr-acinetobacter baumannii

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Hannan, A.; Batool, A.; Qamar, U.; Khalid, F.

2015-01-01

Multidrug resistant (MDR) Acinetobacter baumannii has emerged as an important health care problem. The organism is now identified as an important nosocomial pathogen particularly in the intensive care settings. The therapeutic options to treat this pathogen are limited; thus it needs testing for alternatives, like those of plant origin or natural products. Propolis is one of such products which have been tested against this organism. Methods: A. baumannii (n=32) were collected from Fatima Memorial Hospital, Lahore. The isolates were identified on the basis of their morphology, cultural characteristics and biochemical profile. The susceptibility of the isolates to various antimicrobials was evaluated as per Kirby-Bauer disc diffusion method according to (CLSI 2010). An ethanolic extract of propolis was prepared by the ultrasonic extraction method and its antibacterial activity was evaluated by the agar well diffusion technique. Minimum inhibitory concentration (MIC) was also determined by the agar dilution technique. Results: The isolates were found to be resistant to most of the commonly used anti-acinetobacter antimicrobials; doxycycline however was the exception. Propolis from Sargodha (EPS) and Lahore (EPL) showed zones of inhibition of 21.8 ± .29 mm and 15.66 ± 2.18 mm respectively. MIC ranges of EPS and EPL similarly was from 1.5-2.0 mg/ml and 4.0-4.5 mg/ml respectively. Conclusion: It is clear that EPS has potential edge of activity as compared to EPL. Nevertheless the potential efficacy of propolis must be subjected to pharmaceutical kinetics and dynamics to precisely determine its potential antimicrobial usefulness. (author)

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

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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.

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

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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). Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

PREVALENCE OF MBL AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF ACINETOBACTER ISOLATES FROM A TERTIARY CARE HOSPITAL, ASSAM, INDIA

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Monjuri Kataki

2017-02-01

Full Text Available BACKGROUND Acinetobacter infection have been clinically prominent pathogen in tropical countries have caused recurrent problems during wars and natural disasters and have recently caused multihospital outbreaks. Rational use of antimicrobial agents is clinically important to prevent Acinetobacter infections as well as to avoid poor outcomes. 1 The aim of the study is to see the prevalence of Acinetobacter as a pathogen in this tertiary care hospital, their susceptibility pattern along with prevalence of metallo-beta-lactamase. MATERIALS AND METHODS The samples were processed for a period of one year. Samples were collected from ICU including urine, sputum, endotracheal aspirate, BAL, blood, pus, body fluids (pleural fluid, CSF, etc. and the stool specimens were plated using appropriate culture media (MAC, BA, CLED, XLD. RESULTS Shows Acinetobacter baumannii is the significant species isolated is ICU among 700 cases, which yielded only 100% sensitivity to commonly used antibiotics. So, it is the need of the hour to implement infection control measures in a serious and intensive way. CONCLUSION So, it is the need of the hour to implement infection control measures in a serious and intensive way.

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

International Nuclear Information System (INIS)

Manab Sarma, P.; Bhattacharya, D.; Krishnan, S.; Lal, B.

2004-01-01

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

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.

Effect of multipurpose solutions against Acinetobacter carrying QAC genes.

Science.gov (United States)

Boost, Maureen V; Chan, Jessica; Shi, Guang-sen; Cho, Pauline

2014-03-01

Acinetobacter has low virulence but causes infections in subjects with reduced immunity. It has been reported in ocular infections including those of patients using contact lenses. Treatment is difficult because Acinetobacter is frequently multidrug resistant. Antibiotic-resistant strains frequently also harbor genes for antiseptic resistance (quaternary ammonium compound [QAC]) genes. Because Acinetobacter is part of the normal flora, it may contaminate contact lens and accessories. This study aims to investigate carriage rates of QAC genes in household and clinical isolates of Acinetobacter and to determine the effectiveness of two multipurpose solutions (MPSs) for soft lenses against organisms carrying QAC genes. DNA was extracted from 11 bathroom isolates and 15 clinical isolates and amplified by polymerase chain reaction to determine the presence of qacEΔ1. Gene-positive and gene-negative control strains were used to challenge the two MPSs, and minimum inhibitory concentrations (MICs) of these organisms to benzalkonium chloride and chlorhexidine gluconate were determined. More than 90% of isolates carried qacEΔ1. The MICs of clinical isolates were higher than those of isolates of bathrooms. Both MPSs were able to produce a 3-log reduction in the numbers of all isolates. Although most isolates carried qacEΔ1 and elevated MICs to benzalkonium chloride and chlorhexidine gluconate were observed, all were susceptible to both MPSs tested. However, if there were to be poor compliance with care procedures, it is probable that such organisms could survive in the presence of diluted or expired solutions.

Molecular characterization of β-lactamase genes in clinical isolates of carbapenem-resistant Acinetobacter baumannii.

Science.gov (United States)

Raible, Kevin M; Sen, Bhaswati; Law, Nancy; Bias, Tiffany E; Emery, Christopher L; Ehrlich, Garth D; Joshi, Suresh G

2017-11-16

Acinetobacter baumannii is a nosocomial pathogen which is establishing as a major cause of morbidity and mortality within the healthcare community. The success of this pathogen is largely due to its ability to rapidly gain resistance to antimicrobial therapies and its capability to persist in an abiotic environment through the production of a biofilm. Our tertiary-care hospital has showed high incidence of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates. In this study we explore both genotypic and phenotypic properties of 26 CRAB isolates: 16 isolates were collected from January 2010 to March 2011, and 10 were collected between February and May 2015. We determined that all 26 CRAB isolates possessed multiple β-lactamase genes, including genes from Groups A, C, and D. Specifically, 42% of the isolates possesses the potentially plasmid-borne genes of OXA-23-like or OXA-40-like β-lactamase. The presence of mobile gene element integron cassettes and/or integrases in 88% of the isolates suggests a possible mechanism of dissemination of antibiotic resistance genes. Additionally, the location of insertion sequence (IS) ISAba1 in promotor region of of the OXA-51-like, ADC-7, and ampC genes was confirmed. Multilocus sequence typing (MLST) demonstrated that all 26 CRAB isolates were either sequence type (ST)-229 or ST-2. Interestingly, ST-2 went from being the minority CRAB strain in the 2010-2011 isolates to the predominant strain in the 2015 isolates (from 32 to 90%). We show that the ST-2 strains have an enhanced ability to produce biofilms in comparison to the ST-229 strains, and this fact has potentially led to more successful colonization of the clinical environment over time. This study provides a longitudinal genetic and phenotypic survey of two CRAB sequence types, and suggests how their differing phenotypes may interact with the selective pressures of a hospital setting effecting strain dominance over a 5-year period.

High Proportions of Multidrug-Resistant Acinetobacter spp. Isolates in a District in Western India: A Four-Year Antibiotic Susceptibility Study of Clinical Isolates

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Ingvild Odsbu

2018-01-01

Full Text Available The purpose of the study was to determine the proportions of multidrug-resistant (MDR Acinetobacter spp. isolates from the district of Nashik in Western India during the period from 2011–2014. Antibacterial susceptibility testing of isolates from inpatients and outpatients was performed using Kirby–Bauer disc diffusion method to determine inhibitory zone diameters. Proportions of non-susceptible isolates were calculated from the antibacterial susceptibility data. MDR was defined as an isolate being non-susceptible to at least one antibacterial agent in at least three antibacterial categories. The change in proportions of MDR isolates; extended-spectrum β-lactamase (ESBL-producing isolates; and non-susceptible isolates to specific antibacterial categories over calendar time was investigated by logistic regression. The proportions of MDR and ESBL-producing isolates ranged from 89.4% to 95.9% and from 87.9% to 94.0%; respectively. The proportions of non-susceptible isolates to aminoglycosides; carbapenems; antipseudomonal penicillins/β-lactamase inhibitors; cephalosporins; folate pathway inhibitors; or penicillins/β-lactamase inhibitors exceeded 77.5%. Proportions of fluoroquinolone and tetracycline non-susceptible isolates ranged from 65.3% to 83.3% and from 71.3% to 75.9%; respectively. No changes in trends were observed over time; except for a decreasing trend in fluoroquinolone non-susceptible isolates (OR = 0.75 (95% CI, 0.62–0.91. Significantly higher proportions of non-susceptible; MDR and ESBL-producing isolates were found among isolates from the respiratory system compared to isolates from all other specimen types (p < 0.05. High proportions of MDR Acinetobacter spp. isolates were observed in the period from 2011–2014. Antimicrobial stewardship programmes are needed to prevent the emergence and spread of antibiotic resistance.

The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

DEFF Research Database (Denmark)

Agersø, Yvonne; Petersen, Andreas

2007-01-01

Objectives: To determine the genetic basis for tetracycline and sulphonamide resistance and the prevalence of class I and II integrons in oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Methods: A total of 222 isolates were screened for tetracycline resistance...... and Southern blots with sulII and tet(39) probes were performed on selected isolates. Results: The recently identified tetracycline resistance gene tet(39) was demonstrated in 75% (166/222) of oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Isolates that were also...

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...

Emergence of Oxacillinases in Environmental Carbapenem-Resistant Acinetobacter baumannii Associated with Clinical Isolates.

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Goic-Barisic, Ivana; Hrenovic, Jasna; Kovacic, Ana; Musić, Martina Šeruga

2016-10-01

Six carbapenem-resistant isolates of Acinetobacter baumannii were recovered from untreated and treated municipal wastewater of the capital city of Zagreb, Croatia. Molecular identification of environmental isolates of A. baumannii was performed by amplification, sequencing, and phylogenetic analyses of rpoB gene. The presence of bla OXA genes encoding OXA-type carbapenemases (OXA-51-like, OXA-23, and OXA-40-like) was confirmed by multiplex PCR and sequencing. Phylogenetic analyses corroborated the affiliation of detected bla OXA genes to three different clusters and showed association of environmental OXAs with those described from clinical isolates. This result suggests that isolates recovered from municipal wastewater are most probably of clinical origin. Furthermore, the presence of OXA-40-like (OXA-72) in an environmental A. baumannii isolate is reported for the first time. Persistence of A. baumannii harboring the clinically important OXAs in the wastewater treatment process poses a potentially significant source for horizontal gene transfer and implications for wider spread of antibiotic resistance genes.

Multi-drug-resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex infection outbreak in dogs and cats in a veterinary hospital.

Science.gov (United States)

Kuzi, S; Blum, S E; Kahane, N; Adler, A; Hussein, O; Segev, G; Aroch, I

2016-11-01

Members of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex cause severe outbreaks in humans, and are increasingly reported in animals. A retrospective study, describing a severe outbreak in dogs and cats caused by a multidrug resistant member of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex in a veterinary hospital, between July 2010 and November 2012. The study included 19 dogs and 4 cats. Acinetobacter calcoaceticus-Acinetobacter baumannii complex bacteria were isolated from urine (9 animals), respiratory tract (11), tissues (3) and blood (1). The most common infection-associated findings included fever, purulent discharge from endotracheal tubes, hypotension, and neutropaenia. Infections led to pneumonia, urinary tract infection, cellulitis and sepsis. Infection was transmitted in the intensive care unit, where 22 of 23 animals were initially hospitalised. The mortality rate was 70% (16 of 23 animals), and was higher in cases of respiratory infection compared to other infections. Aggressive environmental cleaning and disinfection, with staff education for personal hygiene and antisepsis, sharply decreased the infection incidence. Health care-associated outbreaks with multidrug resistant Acinetobacter calcoaceticus-Acinetobacter baumannii complex in dogs and cats are potentially highly fatal and difficult to eradicate, warranting monitoring, antiseptic techniques and judicious antibiotic use. © 2016 British Small Animal Veterinary Association.

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

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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.

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

Science.gov (United States)

Jin, Hao; Qiu, Fan; Ji, Hong Jian; Lu, Qiang

2016-04-01

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, Ppolicies are essential to control the emergence of multidrug-resistance Acinetobacter baumannii .

Infections caused by Acinetobacter species and their susceptibility to ...

African Journals Online (AJOL)

Thirty-seven (63%) and 17 (30%) of the Acinetobacter isolates were from wound infections and UTI respectively. All the infections were nosocomially acquired and were associated with compromised host immunity, defective body defence, surgery or urinary catheterization; with Acinetobacter baumannii being the ...

Frequency and antimicrobial susceptibility of acinetobacter species isolated from blood samples of paediatric patients

International Nuclear Information System (INIS)

Javed, A.; Zafar, A.; Ejaz, H.; Zubair, M.

2012-01-01

Objective: Acinetobacter species is a major nosocomial pathogen causing serious infections in immuno-compromised and hospitalized patients. The aim of this study was to determine the frequency and antimicrobial susceptibility pattern of Acinetobacter species in blood samples of paediatric patients. Methodology: This cross sectional observational study was conducted during January to October, 2011 at The Children's Hospital and Institute of Child Health, Lahore. A total number of 12,032 blood samples were analysed during the study period. Acinetobacter species were Bauer disc diffusion method. Results: The blood cultures showed growth in 1,141 cultures out of which 46 (4.0%) were Acinetobacter species. The gender distribution of Acinetobacter species was 29 (63.0%) in males and 17 (37.0%) in females. A good antimicrobial susceptibility pattern of Acinetobacter species was seen with sulbactam-cefoperazone (93.0%), imepenem and meropenem (82.6% (30.4%) was poor. Conclusion: The results of the present study shows high rate of resistance of Acinetobacter species with cephalosporins in nosocomial infections. The sulbactam-cefoperazone, carbapenems and piperacillin-tazobactam showed effective antimicrobial susceptibility against Acinetobacter species. (author)

Interlaboratory reproducibility of DiversiLab rep-PCR typing and clustering of Acinetobacter baumannii isolates.

Science.gov (United States)

Higgins, Paul G; Hujer, Andrea M; Hujer, Kristine M; Bonomo, Robert A; Seifert, Harald

2012-01-01

We have investigated the reproducibility of DiversiLab rep-PCR fingerprints between two laboratories with the aim of determining if the fingerprints and clustering are laboratory-specific or portable. One-hundred non-duplicate Acinetobacter baumannii isolates were used in this study. DNA isolation and rep-PCR were each performed separately in two laboratories and rep-PCR patterns generated in laboratory A were compared with those from laboratory B. Twelve A. baumannii isolates processed in laboratory A showed ≥98 % pattern similarity with the corresponding 12 isolates tested in laboratory B and were considered identical. Sixty-four isolates showed 95-97.9 % similarity with their corresponding isolates. Twenty-three isolates showed 90-94 % similarity with the corresponding isolates, while one isolate showed only 87.4 % similarity. However, intra-laboratory clustering was conserved: isolates that clustered in laboratory A also clustered in laboratory B. While clustering was conserved and reproducible at two different laboratories, demonstrating the robustness of rep-PCR, interlaboratory comparison of individual isolate fingerprints showed more variability. This comparison allows conclusions regarding clonality to be reached independent of the laboratory where the analysis is performed.

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 bla OXA 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 bla OXA-58 , bla OXA-24 , and bla OXA-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 bla OXA-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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

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

Science.gov (United States)

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

2014-10-01

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

Emerging Trend of Acinetobacter Nosocomial Infection in Northeast of Iran

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Samaneh Saed

2015-10-01

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

Phenotypic characterization and colistin susceptibilities of carbapenem-resistant of Pseudomonas aeruginosa and Acinetobacter spp.

Science.gov (United States)

Mohanty, Srujana; Maurya, Vijeta; Gaind, Rajni; Deb, Monorama

2013-11-15

Pseudomonas aeruginosa and Acinetobcter spp. are important nosocomial pathogens and carbapenem resistance is an emerging threat. Therapeutic options for infections with these isolates include colistin. This study was conducted to determine the prevalence of carbapenem resistance in P. aeruginosa and Acinetobacter spp. bloodstream isolates, phenotypically characterize the resistance mechanisms and evaluate the in vitro activity of colistin. Consecutive 145 (95 P.aeruginosa and 50 Acinetobacter spp.) non-repeat isolates were included. Antibiotic susceptibility testing was performed per CLSI guidelines. MIC for carbapenems and colistin was performed using Etest. Isolates showing reduced susceptibility or resistance to the carbapenems were tested for metallo-β-lactamase (MBL) production using imipenem-EDTA combined disk and MBL Etest. Carbapenem resistance was observed in 40% P. aeruginosa and 66.0% Acinetobacter spp. Carbapenem-resistant (CA-R) isolates were significantly (p carbapenem-susceptible isolates. Approximately half of the CA-R strains were multidrug-resistant, and 3.1-5.5% were resistant to all antibiotics tested. MBL was found in 76.3% and 69.7% of the P. aeruginosa and Acinetobacter spp., respectively. Colistin resistance was observed in three (6.0%) Acinetobacter isolates and eight (8.4%) P. aeruginosa. MIC50 for carbapenems were two to four times higher for MBL-positive compared to MBL-negative isolates, but no difference was seen in MIC for colistin. Carbapenem resistance was observed to be mediated by MBL in a considerable number of isolates. Colistin is an alternative for infections caused by CA-R isolates; however, MIC testing should be performed whenever clinical use of colistin is considered.

Association of biofilm production with colonization among clinical isolates of Acinetobacter baumannii.

Science.gov (United States)

Ryu, Seong Yeol; Baek, Won-Ki; Kim, Hyun Ah

2017-03-01

The pathogen Acinetobacter baumannii is increasingly causing healthcare-associated infections worldwide, particularly in intensive care units. Biofilm formation, a factor contributing to the virulence of A. baumannii , is associated with long-term persistence in hospital environments. The present study investigates the clinical impact of biofilm production on colonization and acquisition after patient admission. Forty-nine A. baumannii isolates were obtained between August and November 2013 from Keimyung University Dongsan Medical Center, Daegu, Korea. All isolates were obtained from sputum samples of new patients infected or colonized by A. baumannii . The microtiter plate assay was used to determine biofilm formation. Twenty-four A. baumannii isolates (48%) demonstrated enhanced biofilm formation capacity than that of the standard A. baumannii strain (ATCC 19606). All isolates were resistant to carbapenem, 38 isolates (77%) were collected from patients in an intensive care unit, and 47 isolates (95%) were from patients who had been exposed to antibiotics in the previous month. The median duration of colonization was longer for biofilm-producing isolates than that of the biofilm non-biofilm producing isolates (18 days vs. 12 days, p < 0.05). Simultaneous colonization with other bacteria was more common for biofilm-producing isolates than that for the non-biofilm producing isolates. The most prevalent co-colonizing bacteria was Staphylococcus aureus . Biofilm-producing isolates seem to colonize the respiratory tract for longer durations than the non-biofilm producing isolates. During colonization, biofilm producers promote co-colonization by other bacteria, particularly S. aureus . Additional research is required to determine possible links between biofilm formation and nosocomial infection.

Commensal Staphylococcus spp., Acinetobacter spp. and ...

African Journals Online (AJOL)

ANTHONY

2012-07-31

Jul 31, 2012 ... Intermittent assessment of resistance genes in the ecosystem should be ..... among resistant Acinetobacter spp. isolated from integrated fish .... independent studies on the emerging phylogenetic view of bacterial .... Functional.

Pathogenic Acinetobacter: from the Cell Surface to Infinity and Beyond

Science.gov (United States)

Weber, Brent S.; Harding, Christian M.

2015-01-01

The genus Acinetobacter encompasses multiple nosocomial opportunistic pathogens that are of increasing worldwide relevance because of their ability to survive exposure to various antimicrobial and sterilization agents. Among these, Acinetobacter baumannii, Acinetobacter nosocomialis, and Acinetobacter pittii are the most frequently isolated in hospitals around the world. Despite the growing incidence of multidrug-resistant Acinetobacter spp., little is known about the factors that contribute to pathogenesis. New strategies for treating and managing infections caused by multidrug-resistant Acinetobacter strains are urgently needed, and this requires a detailed understanding of the pathobiology of these organisms. In recent years, some virulence factors important for Acinetobacter colonization have started to emerge. In this review, we focus on several recently described virulence factors that act at the bacterial surface level, such as the capsule, O-linked protein glycosylation, and adhesins. Furthermore, we describe the current knowledge regarding the type II and type VI secretion systems present in these strains. PMID:26712938

[Inventory building of phages against extensively drug-resistant Acinetobacter baumannii isolated from wounds of patients with severe burn and related characteristic analysis].

Science.gov (United States)

Yang, Z C; Deng, L Y; Gong, Y L; Yin, S P; Jiang, B; Huang, G T; Peng, Y Z; Hu, F Q

2016-09-20

To build inventory of phages against extensively drug-resistant Acinetobacter Baumannii isolated from wounds of inpatients of burn ICU and analyze related characteristics. In 2014 and 2015, 131 strains of extensively drug-resistant Acinetobacter Baumannii were isolated from wounds of inpatients of burn ICU from one hospital in Chongqing. In 2015, 98 strains of extensively drug-resistant Acinetobacter Baumannii were isolated from wounds of inpatients of burn ICU from 6 hospitals in Guangdong province. Above-mentioned 229 strains were collected for conducting experiments as follows: (1) Multilocus sequence typing (MLST) of strains isolated from Chongqing and Guangdong province was analyzed. (2) Sewage co-culture method was applied for isolation of phages with above-mentioned strains and sewage from Chongqing and Guangdong province. Numbers of isolated phages and times of successful isolation and unsuccessful isolation were recorded. (3) The most prevalent subtypes of strains from Chongqing and Guangdong province in 2015 were collected, and their phages respectively underwent cross infection with all strains from Chongqing and those from Guangdong province. The lysis ability of phage was observed when phage underwent cross infection with the same subtype of strain or not the same, and the lytic ratio was calculated. (4) Fluid of phage in one type was randomly selected and equally divided into 3 parts, and its titer was determined by double dilution method. Then each part of phage fluid was subdivided into 3 small parts, which were cultured with LB fluid medium and respectively stored under the condition of -20 ℃, 4 ℃, and room temperature. After being stored for 1 month and 2 months, the titer of phage was determined for evaluating stability of phage. Data were processed with Fisher's exact test, chi-square test, and one-way analysis of variance. (1) The major type of strains from Chongqing in 2014 was ST368 (45%, 31/69), and major types of strains from Chongqing

Investigation of colistin sensitivity via three different methods in Acinetobacter baumannii isolates with multiple antibiotic resistance.

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Sinirtaş, Melda; Akalin, Halis; Gedikoğlu, Suna

2009-09-01

In recent years there has been an increase in life-threatening infections caused by Acinetobacter baumannii with multiple antibiotic resistance, which has lead to the use of polymyxins, especially colistin, being reconsidered. The aim of this study was to investigate the colistin sensitivity of A. baumannii isolates with multiple antibiotic resistance via different methods, and to evaluate the disk diffusion method for colistin against multi-resistant Acinetobacter isolates, in comparison to the E-test and Phoenix system. The study was carried out on 100 strains of A. baumannii (colonization or infection) isolated from the microbiological samples of different patients followed in the clinics and intensive care units of Uludağ University Medical School between the years 2004 and 2005. Strains were identified and characterized for their antibiotic sensitivity by Phoenix system (Becton Dickinson, Sparks, MD, USA). In all studied A. baumannii strains, susceptibility to colistin was determined to be 100% with the disk diffusion, E-test, and broth microdilution methods. Results of the E-test and broth microdilution method, which are accepted as reference methods, were found to be 100% consistent with the results of the disk diffusion tests; no very major or major error was identified upon comparison of the tests. The sensitivity and the positive predictive value of the disk diffusion method were found to be 100%. Colistin resistance in A. baumannii was not detected in our region, and disk diffusion method results are in accordance with those of E-test and broth microdilution methods.

First Detection of GES-5 Carbapenemase-Producing Acinetobacter baumannii Isolate.

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Al-Agamy, Mohamed H; Jeannot, Katy; El-Mahdy, Taghrid S; Shibl, Atef M; Kattan, Wael; Plésiat, Patrick; Courvalin, Patrice

2017-07-01

This study was conducted to investigate the molecular epidemiology of resistance in Acinetobacter baumannii isolates collected at a hospital in Riyadh, Saudi Arabia, from January through December 2010. Twenty-seven A. baumannii were highly resistant (MIC 90 > 256 μg/ml) to ceftazidime, cefepime, and aztreonam. Imipenem resistance was seen in 24 isolates, of which 18 had an minimum inhibitory concentration (MIC) >32 μg/mL. Ciprofloxacin, gentamicin, and amikacin resistance was found in 93%, 52%, and 37% of all the isolates, respectively. Moreover, 8 (30%) isolates showed colistin resistance, and 15 (56%) were found to have MICs ≥4 μg/mL for tigecycline. The frequency of ADC, GES-1, GES-11, and GES-5 were 96.3% (n = 26), 18.5% (n = 5), 11% (n = 3), and 3.7% (n = 1), respectively. OXA-23 was found in 63% (n = 17) of the isolates; ISAba1 was found upstream of OXA-23 in 16. OXA-24/40 was detected in only one strain. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) analysis revealed that the 27 strains were distributed in 8 sequence types (STs) and 16 clonal pulsotypes (A-P). Five singleton STs were identified, including ST15 and ST113-ST116. The emergence of multidrug-resistant A. baumannii is becoming a major concern in Saudi Arabia. Metallo-β-lactamases have no role in carbapenem resistance in this collection. The spread of OXA-23 in our strains occurred across different STs and pulsotypes, unlike what has been observed in many other countries. PFGE typing was more discriminatory than MLST. The high frequency of colistin and tigecycline resistance found in the isolates calls for continuous monitoring. This study describes the first identification of GES-5 conferring carbapenem resistance in A. baumannii.

Short communication: Multidrug-resistant Acinetobacter baumannii-calcoaceticus complex isolated from infant milk formula and utensils in a nursery in Rio de Janeiro, Brazil.

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Araújo, B C; Moraes, M S; Costa, L E O; Nascimento, J S

2015-04-01

Infant milk formulas are not sterile products, and pathogenic bacteria can survive and multiply in these products. This study was performed, initially, to detect the presence of Salmonella spp. in reconstituted infant milk formula and on utensils previously sanitized used in their preparation or distribution in a nursery of a public hospital in Rio de Janeiro. None of the samples tested carried Salmonellaspp. However, further identification of colonies growing on the selective media revealed the presence of several other gram-negative bacteria. Seventeen isolates were identified as belonging to Acinetobacter baumannii-calcoaceticus complex. Fourteen isolates presented a multidrug-resistance profile, by disc diffusion assays, and one of them--JE4--was also resistant to imipenem. The detection of Acinetobacter isolates in this work demonstrates inadequate hygiene practices in the preparation or distribution of infant milk formula. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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

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Yesim Cekin

2014-03-01

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

In vitro efficacy of doripenem against pseudomonas aeruginosa and acinetobacter baumannii by e-test

International Nuclear Information System (INIS)

Gilani, M.; Munir, T.; Latif, M.; Rehman, S.

2015-01-01

To assess the in vitro efficacy of doripenem against Pseudomonas aeruginosa and Acinetobacter baumannii using Epsilometer strips. Study Design: Cross-sectional study. Place and Duration of Study: Department of Microbiology, Army Medical College, Rawalpindi and National University of Sciences and Technology, Islamabad, from May 2014 to September 2014. Methodology: A total of 60 isolates of Acinetobacter baumannii and Pseudomonas aeruginosa collected from various clinical samples received from Military Hospital were included in the study. The specimens were inoculated onto blood, MacConkey and chocolate agars. The isolates were identified using Gram staining, motility, catalase test, oxidase test and API 20NE (Biomeriux, France). Organisms identified as Acinetobacter baumannii and Pseudomonas aeruginosa were included in the study. Bacterial suspensions equivalent to 0.5 McFarland turbidity standard of the isolates were prepared and applied on Mueller Hinton agar. Epsilometer strip was placed in the center of the plate and incubated for 18-24 hours. Minimum Inhibitory Concentration (MIC) was taken to be the point where the epsilon intersected the E-strip. MIC of all the isolates was noted. Results: For Pseudomonas aeruginosa isolates, MIC50 was 12 micro g/mL and MIC90 was 32 micro g/mL. For Acinetobacter baumannii MIC 50 and MIC90 was 32 micro g/mL. Conclusion: Doripenem is no more effective against Pseudomonas aeruginosa and Acinetobacter baumannii in our setting. (author)

Identification of genus Acinetobacter: Standardization of in-house PCR and its comparison with conventional phenotypic methods.

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Kulkarni, Sughosh S; Madalgi, Radhika; Ajantha, Ganavalli S; Kulkarni, Raghavendra D

2017-01-01

Acinetobacter is grouped under nonfermenting Gram-negative bacilli. It is increasingly isolated from pathological samples. The ability of this genus to acquire drug resistance and spread in the hospital settings is posing a grave problem in healthcare. Specific treatment protocols are advocated for Acinetobacter infections. Hence, rapid identification and drug susceptibility profiling are critical in the management of these infections. To standardize an in-house polymerase chain reaction (PCR) for identification of genus Acinetobacter and to compare PCR with two protocols for its phenotypic identification. A total of 96 clinical isolates of Acinetobacter were included in the study. An in-house PCR for genus level identification of Acinetobacter was standardized. All the isolates were phenotypically identified by two protocols. The results of PCR and phenotypic identification protocols were compared. The in-house PCR standardized was highly sensitive and specific for the genus Acinetobacter . There was 100% agreement between the phenotypic and molecular identification of the genus. The preliminary identification tests routinely used in clinical laboratories were also in complete agreement with phenotypic and molecular identification. The in-house PCR for genus level identification is specific and sensitive. However, it may not be essential for routine identification as the preliminary phenotypic identification tests used in the clinical laboratory reliably identify the genus Acinetobacter .

Virulence factors and antibiotic susceptibility pattern of Acinetobacter species in a tertiary care hospital in Bangladesh

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Azizun Nahar

2012-01-01

Full Text Available Acinetobacter species are aerobic Gram variable coccobacilli that are now emerging as an important nosocomial pathogen. Infections caused by them are difficult to control due to multidrug resistance. The purpose of this study was to detect virulence factors namely gelatinase production, biofilm formation and antibiotic susceptibility of Acinetobacter species. Two hundred fifty six clinical samples collected from Bangabandhu Sheikh Mujib medical University (BSMMU and from burn unit of Dhaka Medical College Hospital were included in the study. Gelatinase production was seen on Luria Bertani agar media containing gelatin (30 gm/l and biofilm formation was detected in microtiter plate assay. Out of 256 clinical samples, 52 (20.3% were Acinetobacter species. Out of 52 Acinetobacter isolates, none were gelatinase producer but 39 (75% were found biofilm producers. Acinetobacter isolates were 100% resistant to ceftazidime, cefotaxime cefuroxime and ceftriaxone. High level of resistance was also recorded for amoxicillin (98.1%, aztreonam (98.1%, gentamicin (90.4%, ciprofloxacin (73.1%, amikacin (57.6%, netilmicin (53.8% and imipenem (44.2%. Susceptibility to colistin was maximum (96.2%. The present study demonstrated a high propensity of biofilm formation by the clinical isolates of Acinetobacter species and most of the Acinetobacter were multidrug resistant. Ibrahim Med. Coll. J. 2012; 6(1: 27-30

Acinetobacter Infection and Resistance Profile of Intensive Care Units In a City of Northwestern Anatolia

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İsa Yıldız

2016-09-01

Full Text Available INTRODUCTION: Determination of suitable antibiotics in treatment of Acinetobacter infections is through the hospital ascertaining the resistance state to bacteria causing the problem. In this study, the evaluation of antibiotics sensitivity of Acinetobacter strains isolated as infection factor in patients hospitalized in intensive care units is aimed. METHODS: Acinetobacter strains isolated from the samples of patients hospitalized in the 2nd and 3rd Stage adult intensive care units of a province in in northwestern Anatolia have been studied. RESULTS: A total of 165 patients were included in the study. The most isolated samples were respiratory tract samples, blood and urine. The antibiotics which the factors were most sensitive were cholistin (66,1% gentamicin (22,4% and trimethoprim sulfamethoxazole (18,2%. DISCUSSION AND CONCLUSION: We face increasing resistance ratios in Acinetobacter strains. Necessary precautions should be taken for this.

PREVALENCE OF ACINETOBACTER BAUMANNII ISOLATED FROM CLINICAL SPECIMENS IN ADAM MALIK HOSPITAL

OpenAIRE

Evita Mayasari; Cherry Siregar

2014-01-01

AbstrakAcinetobacter baumannii merupakan spesies Acinetobacter spp. tersering diisolasi darimanusia, dan lebih sering dijumpai pada infeksi nosokomial dibandingkan dengan infeksi dikomunitas. Eksistensi bakteri ini di lingkungan terkait dengan keragaman reservoir, kemampuanmemperoleh gen pembawa sifat resisten antimikroba, dan sifat resisten terhadap pengeringan.Infeksi disebabkan strain A.baumannii yang resisten terhadap banyak antibiotik tidak mudahdikendalikan dan menjadi permasalahan di b...

[Identification and typing of hospital strains of Acinetobacter calcoaceticus-Acinetobacter baumanni complex].

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Nemec, A; Urbásková, P; Grimont, F; Vránková, J; Melter, O; Schindler, J

1996-05-01

A collection of 95 strains of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex, isolated between 1991 and 1993 in the Prague Burn Center (BC), was studied. Ninety-one strains were isolated from 43 patients: 50 of them from burnt sites, 22 from endotracheal tube, 13 from urine, 3 from blood and 3 from venous catheter, and 4 strains were isolated from the hospital environment and the nursing staff. The strains were classified by restriction endonuclease fingerprinting of total DNA, plasmid profile analysis, ribotyping, comparison of antibiograms, biotyping and according to epidemiological data, into 31 relatedness groups each of them including 1 to 29 strains, likely to be isolates of the same strain. None of the methods used enabled to distinguish all groups. The importance of the polyphasic approach is emphasized since three multiresistant strains, isolated almost simultaneously in the BC, needed at least two methods to be distinguished (e.g. ribotyping and biotyping). Twenty-eight representative strains of different groups were identified by ribotyping: 18 of them were allocated to genomospecies 2 (A. baumannii), 5 to genomospecies 3 and 5 to genomospecies 13 sensu Tjernberg and Ursing. Only A. baumannii was found to spread among patients. Strains of two multiresistant groups persisted in the BC throughout the period studied and strains of one of these groups were responsible for an outbreak in the autumn of 1993. The methods mentioned above were used to describe 12 multiresistant strains isolated in three hospital wards in other localities. When ribotyped these strains were identified as A. baumannii. The strains of the same origin were identical in their typing profiles while the strains of different origins were easy to differentiate using any of the above methods; nevertheless, 2 of these groups were almost identical to 2 groups of multiresistant strains isolated in the BC.

Distribution of adeB and NDM-1 genes in multidrug resistant Acinetobacter baumannii isolated from infected wound of patients admitted in a tertiary care hospital in Bangladesh.

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Hasan, M J; Shamsuzzaman, S M

2017-12-01

The adeB gene in Acinetobacter baumannii regulates the bacterial internal drug efflux pump that plays a significant role in drug resistance. The aim of our study was to determine the occurrence of adeB gene in multidrug resistant and New Delhi metallo-beta-lactamase-1 (NDM- 1) gene in imipenem resistant Acinetobacter baumannii isolated from wound swab samples in a tertiary care hospital of Bangladesh. A total of 345 wound swab samples were tested for bacterial pathogens. Acinetobacter baumannii was identified by culture and biochemical tests. Antimicrobial susceptibility pattern was determined by the disc diffusion method according to CLSI standards. Extended spectrum beta-lactamases were screened using the double disc synergy technique. Gene encoding AdeB efflux pump and NDM-1 were detected by Polymerase Chain Reaction (PCR). A total 22 (6.37%) Acinetobacter baumannii were identified from 345 wound swab samples and 20 (91%) of them were multidrug resistant. High resistance rates to some antibiotics were seen namely, cefotaxime (95%), amoxyclavulanic acid (90%) and ceftriaxone (82%). All the identified Acinetobacter baumannii were sensitive to colistin and 82% to imipenem. Two (9%) ESBL producing Acinetobacter baumannii strains were detected. adeB gene was detected in 16 (80%) out of 20 multidrug resistant Acinetobacter baumannii. 4 (18%) of 22 Acinetobacter baumannii were imipenem resistant. NDM-1 gene was detected in 2 (50%) of the imipenem resistant strains of Acinetobacter baumannii. The results of this study provide insight into the role of adeB gene as a potential regulator of drug resistance in Acinetobacter baumanni in Bangladesh. NDM-1 gene also contributes in developing such resistance for Acinetobacter baumannii.

Draft Genome Sequences of Six Multidrug-Resistant Clinical Strains of Acinetobacter baumannii, Isolated at Two Major Hospitals in Kuwait.

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Nasser, Kother; Mustafa, Abu Salim; Khan, Mohd Wasif; Purohit, Prashant; Al-Obaid, Inaam; Dhar, Rita; Al-Fouzan, Wadha

2018-04-19

Acinetobacter baumannii is an important opportunistic pathogen in global health care settings. Its dissemination and multidrug resistance pose an issue with treatment and outbreak control. Here, we present draft genome assemblies of six multidrug-resistant clinical strains of A. baumannii isolated from patients admitted to one of two major hospitals in Kuwait. Copyright © 2018 Nasser et al.

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

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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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acinetobacter spp. Infections in Malaysia: A Review of Antimicrobial Resistance Trends, Mechanisms and Epidemiology.

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Mohd Rani, Farahiyah; A Rahman, Nor Iza; Ismail, Salwani; Alattraqchi, Ahmed Ghazi; Cleary, David W; Clarke, Stuart C; Yeo, Chew Chieng

2017-01-01

Acinetobacter spp. are important nosocomial pathogens, in particular the Acinetobacter baumannii - calcoaceticus complex, which have become a global public health threat due to increasing resistance to carbapenems and almost all other antimicrobial compounds. High rates of resistance have been reported among countries in Southeast Asia, including Malaysia. In this review, we examine the antimicrobial resistance profiles of Acinetobacter spp. hospital isolates from Malaysia over a period of nearly three decades (1987-2016) with data obtained from various peer-reviewed publications as well as the Malaysian National Surveillance on Antibiotic Resistance (NSAR). NSAR data indicated that for most antimicrobial compounds, including carbapenems, the peak resistance rates were reached around 2008-2009 and thereafter, rates have remained fairly constant (e.g., 50-60% for carbapenems). Individual reports from various hospitals in Peninsular Malaysia do not always reflect the nationwide resistance rates and often showed higher rates of resistance. We also reviewed the epidemiology and mechanisms of resistance that have been investigated in Malaysian Acinetobacter spp. isolates, particularly carbapenem resistance and found that bla OXA-23 is the most prevalent acquired carbapenemase-encoding gene. From the very few published reports and whole genome sequences that are available, most of the Acinetobacter spp. isolates from Malaysia belonged to the Global Clone 2 (GC2) CC92 group with ST195 being the predominant sequence type. The quality of data and analysis in the national surveillance reports could be improved and more molecular epidemiology and genomics studies need to be carried out for further in-depth understanding of Malaysian Acinetobacter spp. isolates.

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

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

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

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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.

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

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Zhang, Chuanfu; Qiu, Shaofu; Wang, Yong; Qi, Lihua; Hao, Rongzhang; Liu, Xuelin; Shi, Yun; Hu, Xiaofeng; An, Daizhi; Li, Zhenjun; Li, Peng; Wang, Ligui; Cui, Jiajun; Wang, Pan; Huang, Liuyu; Klena, John D; Song, Hongbin

2014-01-01

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.

Molecular detection of aminoglycoside-modifying enzyme genes in Acinetobacter baumannii clinical isolates.

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Heidary, Mohsen; Salimi Chirani, Alireza; Khoshnood, Saeed; Eslami, Gita; Atyabi, Seyyed Mohammad; Nazem, Habibollah; Fazilati, Mohammad; Hashemi, Ali; Soleimani, Saleh

2017-06-01

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.

Draft Genome Sequence of the Plant Growth–Promoting Rhizobacterium Acinetobacter radioresistens Strain SA188 Isolated from the Desert Plant Indigofera argentea

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Lafi, Feras Fawzi; Alam, Intikhab; Bisseling, Ton; Geurts, Rene; Bajic, Vladimir B.; Hirt, Heribert; Saad, Maged

2017-01-01

Acinetobacter radioresistens strain SA188 is a plant endophytic bacterium, isolated from root nodules of the desert plants Indigofera spp., collected in Jizan, Saudi Arabia. Here, we report the 3.2-Mb draft genome sequence of strain SA188, highlighting characteristic pathways for plant growth–promoting activity and environmental adaptation.

Draft Genome Sequence of the Plant Growth–Promoting Rhizobacterium Acinetobacter radioresistens Strain SA188 Isolated from the Desert Plant Indigofera argentea

KAUST Repository

Lafi, Feras Fawzi

2017-03-03

Acinetobacter radioresistens strain SA188 is a plant endophytic bacterium, isolated from root nodules of the desert plants Indigofera spp., collected in Jizan, Saudi Arabia. Here, we report the 3.2-Mb draft genome sequence of strain SA188, highlighting characteristic pathways for plant growth–promoting activity and environmental adaptation.

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

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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

Acinetobacter baumannii displays inverse relationship between meropenem resistance and biofilm production.

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Perez, Leandro Reus Rodrigues

2015-02-01

In this study the ability for biofilm production among meropenem (MEM)-resistant and -susceptible Acinetobacter baumannii isolates was verified. MEM susceptibility and biofilm production were screened in 116 isolates. Meropenem-resistant A. baumannii isolates showed a reduced ability to produce biofilms compared to those susceptible to MEM (Pbaumanni isolates.

Comparative analysis of Acinetobacters: three genomes for three lifestyles.

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David Vallenet

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

Acinetobacter infections prevalence and frequency of the antibiotics ...

African Journals Online (AJOL)

More than a half of the isolates were from the ICUs and were obtained from 293 infected patients of which 65, 2% (191 cases) were males (sex ratio = 1.9) and the median age was 56 years (interquartile range: 42-68 years). Acinetobacter clinical isolates were obtained from respiratory samples (44.67%) followed by blood ...

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

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Chuanfu Zhang

Full Text Available Multidrug resistant microbes present in the environment are a potential public health risk. In this study, we investigate the presence of New Delhi metallo-β-lactamase 1 (NDM-1 producing bacteria in the 99 water samples in Beijing City, including river water, treated drinking water, raw water samples from the pools and sewage from 4 comprehensive hospitals. For the bla NDM-1 positive isolate, antimicrobial susceptibility testing was further analyzed, and Pulsed Field Gel Electrophoresis (PFGE was performed to determine the genetic relationship among the NDM-1 producing isolates from sewage and human, as well as the clinical strains without NDM-1. The results indicate that there was a higher isolation of NDM-1 producing Acinetobacter baumannii from the sewage of the hospitals, while no NDM-1 producing isolates were recovered from samples obtained from the river, drinking, or fishpond water. Surprisingly, these isolates were markedly different from the clinical isolates in drug resistance and pulsed field gel electrophoresis profiles, suggesting different evolutionary relationships. Our results showed that the hospital sewage may be one of the diffusion reservoirs of NDM-1 producing bacteria.

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

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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.

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.

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Kobs, Vanessa Cristine; Ferreira, Jéssica Augustini; Bobrowicz, Thaís Alexandra; Ferreira, Leslie Ecker; Deglmann, Roseneide Campos; Westphal, Glauco Adrieno; França, Paulo Henrique Condeixa de

2016-01-01

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. 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. 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. 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.

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

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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.

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

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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.

Distribution and Molecular Characterization of Acinetobacter baumannii International Clone II Lineage in Japan.

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Matsui, Mari; Suzuki, Masato; Suzuki, Masahiro; Yatsuyanagi, Jun; Watahiki, Masanori; Hiraki, Yoichi; Kawano, Fumio; Tsutsui, Atsuko; Shibayama, Keigo; Suzuki, Satowa

2018-02-01

Multidrug-resistant (MDR) Acinetobacter spp. have been globally disseminated in association with the successful clonal lineage Acinetobacter baumannii international clone II (IC II). Because the prevalence of MDR Acinetobacter spp. in Japan remains very low, we characterized all Acinetobacter spp. ( n = 866) from 76 hospitals between October 2012 and March 2013 to describe the entire molecular epidemiology of Acinetobacter spp. The most prevalent species was A. baumannii ( n = 645; 74.5%), with A. baumannii IC II ( n = 245) accounting for 28.3% of the total. Meropenem-resistant isolates accounted for 2.0% ( n = 17) and carried IS Aba1-bla OXA-23-like ( n = 10), bla IMP ( n = 4), or IS Aba1-bla OXA-51-like ( n = 3). Multilocus sequence typing of 110 representative A. baumannii isolates revealed the considerable prevalence of domestic sequence types (STs). A. baumannii IC II isolates were divided into the domestic sequence type 469 (ST469) ( n = 18) and the globally disseminated STs ST208 ( n = 14) and ST219 ( n = 4). ST469 isolates were susceptible to more antimicrobial agents, while ST208 and ST219 overproduced the intrinsic AmpC β-lactamase. A. baumannii IC II and some A. baumannii non-IC II STs (e.g., ST149 and ST246) were associated with fluoroquinolone resistance. This study revealed that carbapenem-susceptible A. baumannii IC II was moderately disseminated in Japan. The low prevalence of acquired carbapenemase genes and presence of domestic STs could contribute to the low prevalence of MDR A. baumannii A similar epidemiology might have appeared before the global dissemination of MDR epidemic lineages. In addition, fluoroquinolone resistance associated with A. baumannii IC II may provide insight into the significance of A. baumannii epidemic clones. Copyright © 2018 American Society for Microbiology.

Acinetobacter baumannii and A. pittii clinical isolates lack adherence and cytotoxicity to lung epithelial cells in vitro.

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Lázaro-Díez, María; Navascués-Lejarza, Teresa; Remuzgo-Martínez, Sara; Navas, Jesús; Icardo, José Manuel; Acosta, Felix; Martínez-Martínez, Luis; Ramos-Vivas, José

2016-09-01

The molecular and genetic basis of Acinetobacter baumannii and Acinetobacter pittii virulence remains poorly understood, and there is still lack of knowledge in host cell response to these bacteria. In this study, we have used eleven clinical Acinetobacter strains (A. baumannii n = 5; A. pittii n = 6) to unravel bacterial adherence, invasion and cytotoxicity to human lung epithelial cells. Our results showed that adherence to epithelial cells by Acinetobacter strains is scarce and cellular invasion was not truly detected. In addition, all Acinetobacter strains failed to induce any cytotoxic effect on A549 cells. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

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

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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.

Biofilm and metallo beta-lactamase production among the strains of Pseudomonas aeruginosa and Acinetobacter spp. at a Tertiary Care Hospital in Kathmandu, Nepal

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Bandana Baniya

2017-11-01

Full Text Available Abstract Introduction Pseudomonas aeruginosa and Acinetobacter spp. are found to be associated with biofilm and metallo-β-lactamase production and are the common causes of serious infections mainly in hospitalized patients. So, the main aims of this study were to determine the rates of biofilm production and metallo beta-lactamase production (MBL among the strains of Pseudomonas aeruginosa and Acinetobacter spp. isolated from hospitalized patients. Methods A total of 85 P. aeruginosa isolates and 50 Acinetobacter spp. isolates isolated from different clinical specimens from patients admitted to Shree Birendra Hospital, Kathmandu, Nepal from July 2013 to May 2014 were included in this study. The bacterial isolates were identified with the help of biochemical tests. Modified Kirby-Bauer disc diffusion technique was used for antimicrobial susceptibility testing. Combined disc diffusion technique was used for the detection of MBL production, while Congo red agar method and tube adherence method were used for detection of biofilm production. Results Around 16.4% of P. aeruginosa isolates and 22% of the strains of Acinetobacter spp. were metallo β-lactamase producers. Out of 85 P. aeruginosa isolates, 23 (27.05% were biofilm producers according to tube adherence test while, only 13 (15.29% were biofilm producers as per Congo red agar method. Similarly, out of 50 Acinetobacter spp. 7 (14% isolates were biofilm producers on the basis of tube adherence test, while only 5 (10% were positive for biofilm production by Congo red agar method. Highest rates of susceptibility of P. aeruginosa as well as Acinetobacter spp. were seen toward colistin. Conclusion In our study, biofilm production and metallo beta-lactamase production were observed among Pseudomonas aeruginosa and Acinetobacter spp. However, no statistically significant association could be established between biofilm production and metallo beta-lactamase production.

Characterization of a novel plasmid type and various genetic contexts of bla OXA-58 in Acinetobacter spp. from multiple cities in China.

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Yiqi Fu

Full Text Available BACKGROUND/OBJECTIVE: Several studies have described the epidemiological distribution of blaOXA-58-harboring Acinetobacter baumannii in China. However, there is limited data concerning the replicon types of blaOXA-58-carrying plasmids and the genetic context surrounding blaOXA-58 in Acinetobacter spp. in China. METHODOLOGY/PRINCIPAL FINDINGS: Twelve non-duplicated blaOXA-58-harboring Acinetobacter spp. isolates were collected from six hospitals in five different cities between 2005 and 2010. The molecular epidemiology of the isolates was carried out using PFGE and multilocus sequence typing. Carbapenemase-encoding genes and plasmid replicase genes were identified by PCR. The genetic location of blaOXA-58 was analyzed using S1-nuclease method. Plasmid conjugation and electrotransformation were performed to evaluate the transferability of blaOXA-58-harboring plasmids. The genetic structure surrounding blaOXA-58 was determined by cloning experiments. The twelve isolates included two Acinetobacter pittii isolates (belong to one pulsotype, three Acinetobacter nosocomialis isolates (belong to two pulsotypes and seven Acinetobacter baumannii isolates (belong to two pulsotypes/sequence types. A. baumannii ST91 was found to be a potential multidrug resistant risk clone carrying both blaOXA-58 and blaOXA-23. blaOXA-58 located on plasmids varied from ca. 52 kb to ca. 143 kb. All plasmids can be electrotransformed to A. baumannii recipient, but were untypeable by the current replicon typing scheme. A novel plasmid replicase named repAci10 was identified in blaOXA-58-harboring plasmids of two A. pittii isolates, three A. nosocomialis isolates and two A. baumannii isolates. Four kinds of genetic contexts of blaOXA-58 were identified. The transformants of plasmids with structure of IS6 family insertion sequence (ISOur1, IS1008 or IS15-ΔISAba3-like element-blaOXA-58 displayed carbapenem nonsusceptible, while others with structure of intact ISAba3-like element

First case of bacteraemia due to Acinetobacter schindleri harbouring blaNDM-1 in an immunocompromised patient

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S. Montaña

2018-01-01

Full Text Available Clinically significant NDM-1-producing Acinetobacter schindleri has not yet been described in the literature. We report the first case of bacteraemia due to an A. schindleri strain harbouring blaNDM-1 recovered from an immunocompromised patient. Our report reinforces the fact that NDM-1 can easily be acquired by Acinetobacter species. Keywords: Acinetobacter schindleri, bacteraemia, blaNDM-1, clinically significant isolate, immunocompromised patient

Genome Sequence of Jumbo Phage vB_AbaM_ME3 of Acinetobacter baumanni

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Buttimer, Colin; O?Sullivan, Lisa; Elbreki, Mohamed; Neve, Horst; McAuliffe, Olivia; Ross, R. Paul; Hill, Colin; O?Mahony, Jim; Coffey, Aidan

2016-01-01

Bacteriophage (phage) vB_AbaM_ME3 was previously isolated from wastewater effluent using the propagating host Acinetobacter baumannii DSM 30007. The full genome was sequenced, revealing it to be the largest Acinetobacter bacteriophage sequenced to date with a size of 234,900 bp and containing 326 open reading frames (ORFs).

RESISTENCIA A LOS ANTIBIÓTICOS EN CEPAS DE KLEBSIELLA PNEUMONIAE, SERRATIA SPP. Y ACINETOBACTER SPP.AISLADAS DE PACIENTES CON INFECCIÓN DEL TRACTO URINARIO - LIMA, PERU

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Luján Roca DA

2013-01-01

Full Text Available INFECTION - LIMA, PERU Introduction: Urinary tract infection (UTI is one of the most common infections in clinical practice. Gram negative bacteria as Klebsiella pneumoniae, Serratia spp. and Acinetobacter spp. can cause UTI. Objective: To study antibiotic resistance in K. pneumoniae, Serratia spp. and Acinetobacter spp. strains isolated from UTI Material and methods: Urine cultures were collected from January 2003 to December 2003. Identification of isolated bacteria included biochemical characteristics. Bauer-Kirby disc diffusion test was performed. Results: A total of 106 strains were evaluated (41 of K. pneumoniae, 28 of Serratia spp. and 37 of Acinetobacter spp.. Among K. pneumoniae isolates resistance to ampicillin (83% was remarkable. The Serratia spp. isolates displayed a high level of resistance to nalidixic acid (79% and gentamicin (75%. In Acinetobacter spp. isolates high resistance rates were observed against amikacin (81%, gentamicin (67% and trimethoprim/sulfamethoxazole(71%. Conclusions: In general, antibiotic resistance patterns were high. Acinetobacter spp. showed elevated resistance rates (>50% against antibiotics included.

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

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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

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

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Yesim Cekin

2014-01-01

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 ...

Contamination of Ambient Air with Acinetobacter baumannii on Consecutive Inpatient Days.

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Shimose, Luis A; Doi, Yohei; Bonomo, Robert A; De Pascale, Dennise; Viau, Roberto A; Cleary, Timothy; Namias, Nicholas; Kett, Daniel H; Munoz-Price, L Silvia

2015-07-01

Acinetobacter-positive patients had their ambient air tested for up to 10 consecutive days. The air was Acinetobacter positive for an average of 21% of the days; the rate of contamination was higher among patients colonized in the rectum than in the airways (relative risk [RR], 2.35; P = 0.006). Of the 6 air/clinical isolate pairs available, 4 pairs were closely related according to rep-PCR results. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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

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Fitzpatrick, Margaret A.; Hauser, Alan R.

2015-01-01

Acinetobacter baumannii frequently causes nosocomial infections and outbreaks. Whole-genome sequencing (WGS) is a promising technique for strain typing and outbreak investigations. We compared the performance of conventional methods with WGS for strain typing clinical Acinetobacter isolates and analyzing a carbapenem-resistant A. baumannii (CRAB) outbreak. We performed two band-based typing techniques (pulsed-field gel electrophoresis and repetitive extragenic palindromic-PCR), multilocus sequence type (MLST) analysis, and WGS on 148 Acinetobacter calcoaceticus-A. baumannii complex bloodstream isolates collected from a single hospital from 2005 to 2012. Phylogenetic trees inferred from core-genome single nucleotide polymorphisms (SNPs) confirmed three Acinetobacter species within this collection. Four major A. baumannii clonal lineages (as defined by MLST) circulated during the study, three of which are globally distributed and one of which is novel. WGS indicated that a threshold of 2,500 core SNPs accurately distinguished A. baumannii isolates from different clonal lineages. The band-based techniques performed poorly in assigning isolates to clonal lineages and exhibited little agreement with sequence-based techniques. After applying WGS to a CRAB outbreak that occurred during the study, we identified a threshold of 2.5 core SNPs that distinguished nonoutbreak from outbreak strains. WGS was more discriminatory than the band-based techniques and was used to construct a more accurate transmission map that resolved many of the plausible transmission routes suggested by epidemiologic links. Our study demonstrates that WGS is superior to conventional techniques for A. baumannii strain typing and outbreak analysis. These findings support the incorporation of WGS into health care infection prevention efforts. PMID:26699703

Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites

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Silambarasan, Sivagnanam [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Vangnai, Alisa S., E-mail: alisa.v@chula.ac.th [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok 10330 (Thailand)

2016-01-25

Highlights: • Acinetobacter sp. AVLB2 is a PGPB able to degrade high concentration of 4-NA. • Growth and degradation kinetics for 4-NA removal by AVLB2 were studied. • A novel biodegradation pathway for 4-nitroaniline has been proposed. • Toxicological studies revealed non-toxic nature of 4-NA biodegraded metabolites. • Acinetobacter sp. AVLB2 could maintain PGP traits under 4-NA stress. - Abstract: 4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μ{sub max}, K{sub s} and K{sub i}, were determined to be 0.039 h{sup −1}, 6.623 mg L{sup −1} and 25.57 mg L{sup −1}, respectively using Haldane inhibition model, while the maximum biodegradation rate (V{sub max}) of 4-NA was at 0.541 mg L{sup −1} h{sup −1} and 0.551 mg L{sup −1} h{sup −1}, following Michaelis–Menten and Hanes–Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment.

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

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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.

Genome Sequence of Jumbo Phage vB_AbaM_ME3 of Acinetobacter baumanni.

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Buttimer, Colin; O'Sullivan, Lisa; Elbreki, Mohamed; Neve, Horst; McAuliffe, Olivia; Ross, R Paul; Hill, Colin; O'Mahony, Jim; Coffey, Aidan

2016-08-25

Bacteriophage (phage) vB_AbaM_ME3 was previously isolated from wastewater effluent using the propagating host Acinetobacter baumannii DSM 30007. The full genome was sequenced, revealing it to be the largest Acinetobacter bacteriophage sequenced to date with a size of 234,900 bp and containing 326 open reading frames (ORFs). Copyright © 2016 Buttimer et al.

Prevalence of Ambler class A β-lactamases and ampC expression in cephalosporin-resistant isolates of Acinetobacter baumannii.

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Rezaee, Mohammad Ahangarzadeh; Pajand, Omid; Nahaei, Mohammad Reza; Mahdian, Reza; Aghazadeh, Mohammad; Ghojazadeh, Morteza; Hojabri, Zoya

2013-07-01

We examined the prevalence of various cephalosporins' resistance mechanisms in Acinetobacter baumannii clinical isolates. Phenotypic and molecular detection of Ambler classes A, B and D β-lactamases was performed on 75 isolates. Clonal relatedness was defined using Repetitive Extragenic Palindromic PCR. PCR mapping was used to examine the linkage of insertion sequences and the ampC gene, and ampC expression was analyzed by TaqMan reverse transcriptase-PCR. Twenty-six (37%) isolates carried at least one of the blaPER-1 or blaTEM-1. Sixty-nine (98.5%) out of 70 cephalosporin-resistant isolates had insertions upstream of the ampC gene, of which 48 (69%) and 6 (8%) were identified as ISAba1and ISAba125, respectively. Higher level of expression was obtained in resistant isolates lacking ISAba1/ampC combination in comparison with that in positive ones. The ability to up-regulate the expression of ampC gene in association with different insertion elements has become an important factor in A. baumannii resistance to cephalosporins. Copyright © 2013 Elsevier Inc. All rights reserved.

Isolation and characterization of diesel degrading bacteria, Sphingomonas sp. and Acinetobacter junii from petroleum contaminated soil

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Zhang, Qiuzhuo; Wang, Duanchao; Li, Mengmeng; Xiang, Wei-Ning; Achal, Varenyam

2014-03-01

Two indigenous bacteria of petroleum contaminated soil were characterized to utilize diesel fuel as the sole carbon and energy sources in this work. 16S rRNA gene sequence analysis identified these bacteria as Sphingomonas sp. and Acinetobacter junii. The ability to degrade diesel fuel has been demonstrated for the first time by these isolates. The results of IR analyses showed that Sphingomonas sp. VA1 and A. junii VA2 degraded up to 82.6% and 75.8% of applied diesel over 15 days, respectively. In addition, Sphingomonas sp. VA1 possessed the higher cellular hydrophobicities of 94% for diesel compared to 81% by A. junii VA2. The isolates Sphingomonas sp. VA1 and A. junii VA2 exhibited 24% and 18%, respectively emulsification activity. This study reports two new diesel degrading bacterial species, which can be effectively used for bioremediation of petroleum contaminated sites.

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

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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.

Acinetobacter Peritoneal Dialysis Peritonitis: A Changing Landscape over Time

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Chao, Chia-Ter; Lee, Szu-Ying; Yang, Wei-Shun; Chen, Huei-Wen; Fang, Cheng-Chung; Yen, Chung-Jen; Chiang, Chih-Kang; Hung, Kuan-Yu; Huang, Jenq-Wen

2014-01-01

Background Acinetobacter species are assuming an increasingly important role in modern medicine, with their persistent presence in health-care settings and antibiotic resistance. However, clinical reports addressing this issue in patients with peritoneal dialysis (PD) peritonitis are rare. Methods All PD peritonitis episodes caused by Acinetobacter that occurred between 1985 and 2012 at a single centre were retrospectively reviewed. Clinical features, microbiological data, and outcomes were analysed, with stratifications based upon temporal periods (before and after 2000). Results Acinetobacter species were responsible for 26 PD peritonitis episodes (3.5% of all episodes) in 25 patients. A. baumannii was the most common pathogen (54%), followed by A. iwoffii (35%), with the former being predominant after 2000. Significantly more episodes resulted from breaks in exchange sterility after 2000, while those from exit site infections decreased (P = 0.01). The interval between the last and current peritonitis episodes lengthened significantly after 2000 (5 vs. 13.6 months; P = 0.05). All the isolates were susceptible to cefepime, fluoroquinolone, and aminoglycosides, with a low ceftazidime resistance rate (16%). Nearly half of the patients (46%) required hospitalisation for their Acinetobacter PD-associated peritonitis, and 27% required an antibiotic switch. The overall outcome was fair, with no mortality and a 12% technique failure rate, without obvious interval differences. Conclusions The temporal change in the microbiology and origin of Acinetobacter PD-associated peritonitis in our cohort suggested an important evolutional trend. Appropriate measures, including technique re-education and sterility maintenance, should be taken to decrease the Acinetobacter peritonitis incidence in PD patients. PMID:25314341

Acinetobacter peritoneal dialysis peritonitis: a changing landscape over time.

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Chia-Ter Chao

Full Text Available Acinetobacter species are assuming an increasingly important role in modern medicine, with their persistent presence in health-care settings and antibiotic resistance. However, clinical reports addressing this issue in patients with peritoneal dialysis (PD peritonitis are rare.All PD peritonitis episodes caused by Acinetobacter that occurred between 1985 and 2012 at a single centre were retrospectively reviewed. Clinical features, microbiological data, and outcomes were analysed, with stratifications based upon temporal periods (before and after 2000.Acinetobacter species were responsible for 26 PD peritonitis episodes (3.5% of all episodes in 25 patients. A. baumannii was the most common pathogen (54%, followed by A. iwoffii (35%, with the former being predominant after 2000. Significantly more episodes resulted from breaks in exchange sterility after 2000, while those from exit site infections decreased (P = 0.01. The interval between the last and current peritonitis episodes lengthened significantly after 2000 (5 vs. 13.6 months; P = 0.05. All the isolates were susceptible to cefepime, fluoroquinolone, and aminoglycosides, with a low ceftazidime resistance rate (16%. Nearly half of the patients (46% required hospitalisation for their Acinetobacter PD-associated peritonitis, and 27% required an antibiotic switch. The overall outcome was fair, with no mortality and a 12% technique failure rate, without obvious interval differences.The temporal change in the microbiology and origin of Acinetobacter PD-associated peritonitis in our cohort suggested an important evolutional trend. Appropriate measures, including technique re-education and sterility maintenance, should be taken to decrease the Acinetobacter peritonitis incidence in PD patients.

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

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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.

Impact of terminal cleaning and disinfection on isolation of Acinetobacter baumannii complex from inanimate surfaces of hospital rooms by quantitative and qualitative methods.

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Manian, Farrin A; Griesnauer, Sandra; Senkel, Diane

2013-04-01

Quantitative broth cultures were obtained from hospital rooms newly vacated by patients positive for multidrug-resistant Acinetobacter baumannii complex (ABC) before and after terminal cleaning and disinfection. Of 10 ABC-positive precleaned room surfaces, 6 (60%) remained culture-positive after terminal cleaning and disinfection. Of a total of 16 room surfaces with detectable ABC by the quantitative method, 5 (31.2%; 95% confidence interval, 13.9%-55.8%) were also culture-positive by the qualitative technique. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

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.

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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.

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

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Neda Farahani

2013-03-01

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

Isolation and characterization of ZZ1, a novel lytic phage that infects Acinetobacter baumannii clinical isolates

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Jin Jing

2012-07-01

Full Text Available Abstract Background Acinetobacter baumannii, a significant nosocomial pathogen, has evolved resistance to almost all conventional antimicrobial drugs. Bacteriophage therapy is a potential alternative treatment for multidrug-resistant bacterial infections. In this study, one lytic bacteriophage, ZZ1, which infects A. baumannii and has a broad host range, was selected for characterization. Results Phage ZZ1 and 3 of its natural hosts, A. baumanni clinical isolates AB09V, AB0902, and AB0901, are described in this study. The 3 strains have different sensitivities to ZZ1, but they have the same sensitivity to antibiotics. They are resistant to almost all of the antibiotics tested, except for polymyxin. Several aspects of the life cycle of ZZ1 were investigated using the sensitive strain AB09V under optimal growth conditions. ZZ1 is highly infectious with a short latent period (9 min and a large burst size (200 PFU/cell. It exhibited the most powerful antibacterial activity at temperatures ranging from 35°C to 39°C. Moreover, when ZZ1 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 9 and at extreme temperatures (between 50°C and 60°C. ZZ1 possesses a 100-nm icosahedral head containing double-stranded DNA with a total length of 166,682 bp and a 120-nm long contractile tail. Morphologically, it could be classified as a member of the Myoviridae family and the Caudovirales order. Bioinformatic analysis of the phage whole genome sequence further suggested that ZZ1 was more likely to be a new member of the Myoviridae phages. Most of the predicted ORFs of the phage were similar to the predicted ORFs from other Acinetobacter phages. Conclusion The phage ZZ1 has a relatively broad lytic spectrum, high pH stability, strong heat resistance, and efficient antibacterial potential at body temperature. These characteristics greatly increase the utility of this phage as an antibacterial agent

Isolation and characterization of ZZ1, a novel lytic phage that infects Acinetobacter baumannii clinical isolates.

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Jin, Jing; Li, Zhen-Jiang; Wang, Shu-Wei; Wang, Shan-Mei; Huang, De-Hai; Li, Ya-Hui; Ma, Yun-Yun; Wang, Jin; Liu, Fang; Chen, Xiang-Dong; Li, Guang-Xing; Wang, Xiao-Ting; Wang, Zhong-Quan; Zhao, Guo-Qiang

2012-07-28

Acinetobacter baumannii, a significant nosocomial pathogen, has evolved resistance to almost all conventional antimicrobial drugs. Bacteriophage therapy is a potential alternative treatment for multidrug-resistant bacterial infections. In this study, one lytic bacteriophage, ZZ1, which infects A. baumannii and has a broad host range, was selected for characterization. Phage ZZ1 and 3 of its natural hosts, A. baumanni clinical isolates AB09V, AB0902, and AB0901, are described in this study. The 3 strains have different sensitivities to ZZ1, but they have the same sensitivity to antibiotics. They are resistant to almost all of the antibiotics tested, except for polymyxin. Several aspects of the life cycle of ZZ1 were investigated using the sensitive strain AB09V under optimal growth conditions. ZZ1 is highly infectious with a short latent period (9 min) and a large burst size (200 PFU/cell). It exhibited the most powerful antibacterial activity at temperatures ranging from 35°C to 39°C. Moreover, when ZZ1 alone was incubated at different pHs and different temperatures, the phage was stable over a wide pH range (4 to 9) and at extreme temperatures (between 50°C and 60°C). ZZ1 possesses a 100-nm icosahedral head containing double-stranded DNA with a total length of 166,682 bp and a 120-nm long contractile tail. Morphologically, it could be classified as a member of the Myoviridae family and the Caudovirales order. Bioinformatic analysis of the phage whole genome sequence further suggested that ZZ1 was more likely to be a new member of the Myoviridae phages. Most of the predicted ORFs of the phage were similar to the predicted ORFs from other Acinetobacter phages. The phage ZZ1 has a relatively broad lytic spectrum, high pH stability, strong heat resistance, and efficient antibacterial potential at body temperature. These characteristics greatly increase the utility of this phage as an antibacterial agent; thus, it should be further investigated.

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

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Dann Turner

Full Text Available 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.

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

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Dwibedi, Chinmay Kumar; Sjöström, Karin; Edquist, Petra; Wai, Sun Nyunt; Uhlin, Bernt Eric

2016-01-01

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. PMID:26824943

Acinetobacter infections as an emerging threat in intensive care units

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Tahseen, U.; Talib, M.T.

2015-01-01

Nosocomial infections caused by Acinetobacter species (Spp.) is an emerging threat in health care setups especially intensive care units (ICU). The objective of this observational study was to determine the pattern of Acinetobacter infections and its association with length of stay in patients admitted to our medical ICU from January to August 2011. Methods: All patients above 16 years of age with stay of more than 48 hours were checked for any development of new infections not present or incubating at the time of admission. Nosocomial infections were documented in the light of clinical findings and lab results. Data was analysed using statistical software SPSS 15.0. Results: A total of 146 patients had a stay of at least 48 hours; frequency of nosocomial infection was 30.8% out of which 57.8% were Acinetobacter infections. Respiratory system was most commonly involved. Acinetobacter Spp showed high resistance (96.2%) to penicillins, cephalosporins and even extended spectrum antibiotics including carbepenems, quinolones and piperacillin plus tazobactam. Extended drug resistance was seen in 92.3% isolates; while we found high susceptibility to tigecycline (88.5%) and polymyxins (100%). Acinetobacter Spp. infected patients had mean length of stay (LOS) of 12.92 days when compared to patients with other nosocomial infections and no infection with mean LOS of 7.05 days (p=0.05) and 4.86 days (p=0.00) respectively. Conclusions: Acinetobacter Spp infections increase with longer duration of stay in ICU. Emergence of multi-drug and extended-drug resistant Acinetobacter Spp is alarming and overwhelming at this rate for already stretched out health system with its economic and health implications. (author)

PCR Assay Based on the gyrB Gene for Rapid Identification of Acinetobacter baumannii-calcoaceticus Complex at Specie Level.

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Teixeira, Aline B; Barin, Juliana; Hermes, Djuli M; Barth, Afonso L; Martins, Andreza F

2017-05-01

The genus Acinetobacter sp. comprises more than 50 species, and four are closely related and difficult to be distinguished by either phenotypic or genotypic methods: the Acinetobacter calcoaceticus-baumannii complex (ABC). The correct identification at species level is necessary mainly due to the epidemiological aspects. We evaluated a multiplex PCR for gyrB gene to identify the species of the ABC using the sequencing of the ITS 16S-23S fragment as a gold standard. Isolates identified as Acinetobacter calcoaceticus-baumannii from three hospitals at southern Brazil in 2011 were included in this study. A total of 117 isolates were obtained and 106 (90.6%) were confirmed as A. baumannii, 6 (5.1%) as A. nosocomialis and 4 (3.4%) as A. pittii by PCR for gyrB gene. Only one isolate did not present a product of the PCR for the gyrB gene; this isolate was identified as Acinetobacter genospecie 10 by sequencing of ITS. We also noted that the non-A. baumannii isolates were recovered from respiratory tract (8/72.7%), blood (2/18.2%) and urine (1/9.1%), suggesting that these species can cause serious infection. These findings evidenced that the multiplex PCR of the gyrB is a feasible and simple method to identify isolates of the ABC at the species level. © 2016 Wiley Periodicals, Inc.

Copper Resistance of the Emerging Pathogen Acinetobacter baumannii

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Williams, Caitlin L.; Neu, Heather M.; Gilbreath, Jeremy J.; Michel, Sarah L. J.; Zurawski, Daniel V.

2016-01-01

ABSTRACT Acinetobacter baumannii is an important emerging pathogen that is capable of causing many types of severe infection, especially in immunocompromised hosts. Since A. baumannii can rapidly acquire antibiotic resistance genes, many infections are on the verge of being untreatable, and novel therapies are desperately needed. To investigate the potential utility of copper-based antibacterial strategies against Acinetobacter infections, we characterized copper resistance in a panel of recent clinical A. baumannii isolates. Exposure to increasing concentrations of copper in liquid culture and on solid surfaces resulted in dose-dependent and strain-dependent effects; levels of copper resistance varied broadly across isolates, possibly resulting from identified genotypic variation among strains. Examination of the growth-phase-dependent effect of copper on A. baumannii revealed that resistance to copper increased dramatically in stationary phase. Moreover, A. baumannii biofilms were more resistant to copper than planktonic cells but were still susceptible to copper toxicity. Exposure of bacteria to subinhibitory concentrations of copper allowed them to better adapt to and grow in high concentrations of copper; this copper tolerance response is likely achieved via increased expression of copper resistance mechanisms. Indeed, genomic analysis revealed numerous putative copper resistance proteins that share amino acid homology to known proteins in Escherichia coli and Pseudomonas aeruginosa. Transcriptional analysis revealed significant upregulation of these putative copper resistance genes following brief copper exposure. Future characterization of copper resistance mechanisms may aid in the search for novel antibiotics against Acinetobacter and other highly antibiotic-resistant pathogens. IMPORTANCE Acinetobacter baumannii causes many types of severe nosocomial infections; unfortunately, some isolates have acquired resistance to almost every available antibiotic

Copper Resistance of the Emerging Pathogen Acinetobacter baumannii.

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Williams, Caitlin L; Neu, Heather M; Gilbreath, Jeremy J; Michel, Sarah L J; Zurawski, Daniel V; Merrell, D Scott

2016-10-15

Acinetobacter baumannii is an important emerging pathogen that is capable of causing many types of severe infection, especially in immunocompromised hosts. Since A. baumannii can rapidly acquire antibiotic resistance genes, many infections are on the verge of being untreatable, and novel therapies are desperately needed. To investigate the potential utility of copper-based antibacterial strategies against Acinetobacter infections, we characterized copper resistance in a panel of recent clinical A. baumannii isolates. Exposure to increasing concentrations of copper in liquid culture and on solid surfaces resulted in dose-dependent and strain-dependent effects; levels of copper resistance varied broadly across isolates, possibly resulting from identified genotypic variation among strains. Examination of the growth-phase-dependent effect of copper on A. baumannii revealed that resistance to copper increased dramatically in stationary phase. Moreover, A. baumannii biofilms were more resistant to copper than planktonic cells but were still susceptible to copper toxicity. Exposure of bacteria to subinhibitory concentrations of copper allowed them to better adapt to and grow in high concentrations of copper; this copper tolerance response is likely achieved via increased expression of copper resistance mechanisms. Indeed, genomic analysis revealed numerous putative copper resistance proteins that share amino acid homology to known proteins in Escherichia coli and Pseudomonas aeruginosa Transcriptional analysis revealed significant upregulation of these putative copper resistance genes following brief copper exposure. Future characterization of copper resistance mechanisms may aid in the search for novel antibiotics against Acinetobacter and other highly antibiotic-resistant pathogens. Acinetobacter baumannii causes many types of severe nosocomial infections; unfortunately, some isolates have acquired resistance to almost every available antibiotic, and treatment options

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

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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.

Unusual genetic heterogeneity of Acinetobacter baumannii isolates in a university hospital in Italy.

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Villari, P; Iacuzio, L; Vozzella, E A; Bosco, U

1999-06-01

Acinetobacter baumannii has become an increasingly important nosocomial pathogen, particularly in intensive care units (ICUs). The aim of this investigation was to study the molecular epidemiology of A baumanii in a university hospital in Italy. All A baumanii isolates were collected and typed with phenotypic and genotypic methods during a 7-month period. A 1-year prospective surveillance of ICU-acquired infections was performed by using the National Nosocomial Infections Surveillance methodology. A baumanni accounted for 28.4% of all infections and 46.7% of all pneumonia acquired in the ICU, with a nosocomial infection rate of 12.4% or 8 infections per 1000 patient-days. Risk factors for A baumannii acquisition in the ICU were mechanical ventilation and previous use of broad-spectrum antibiotics, whereas administration of carbapenems showed a significant protective effect. Pulsed-field gel electrophoresis of genomic Apa I digests identified at least 5 outbreaks in the ICU caused by 5 different clones, one replacing the other in a well-defined temporal order. Whereas the sequential temporal cluster of epidemic clones in the ICU is intriguing and requires further research, the clear evidence of cross-contamination of A baumannii isolates involved with infections in the ICU demands extensive preventive efforts.

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

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Nitin Kumar Singh

2014-12-01

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

Changes in antimicrobial resistance of clinical isolates of Acinetobacter baumannii group isolated in Greece, 2010-2015.

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Dafopoulou, K; Tsakris, A; Pournaras, S

2018-04-01

In recent years, hospitals in southeastern Europe have faced dramatically high rates of antibiotic-resistant Acinetobacter baumannii. We analysed the evolution of resistance among clinical isolates of A. baumannii group obtained from nine tertiary hospitals throughout Greece over 6 years (2010-2015). Identification and antimicrobial susceptibility testing were performed using Vitek 2 or Microscan walkaway automated systems. Between 2010 and 2015, resistance to ampicillin/sulbactam increased from 46.2 to 88.2 % (P=0.021), resistance to gentamicin increased from 69.3 to 86.4 % (P=0.014) and resistance to tobramycin increased from 59.8 to 76.8 % (P=0.011). Imipenem resistance rates were consistently very high, ranging from 90.3 % in 2010 to 94.5 % in 2015 (P=0.198), while meropenem resistance rates increased from 82.6 % in 2010 to 94.8 % in 2015 (P=0.006). Resistance rates to trimethoprim/sulfamethoxazole showed a remarkable decreasing trend, declining from 90.2 % in 2010 to 69.1 % in 2015 (P=0.035). These evolutions render the treatment of A. baumannii infections particularly challenging and underline the need for enhanced infection control measures.

Activities of colistin- and minocycline-based combinations against extensive drug resistant Acinetobacter baumannii isolates from intensive care unit patients

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Li Jian

2011-04-01

Full Text Available Abstract Background Extensive drug resistance of Acinetobacter baumannii is a serious problem in the clinical setting. It is therefore important to find active antibiotic combinations that could be effective in the treatment of infections caused by this problematic 'superbug'. In this study, we analyzed the in vitro activities of three colistin-based combinations and a minocycline-based combination against clinically isolated extensive drug resistant Acinetobacter baumannii (XDR-AB strains. Methods Fourteen XDR-AB clinical isolates were collected. The clonotypes were determined by polymerase chain reaction-based fingerprinting. Susceptibility testing was carried out according to the standards of the Clinical and Laboratory Standards Institute. Activities of drug combinations were investigated against four selected strains and analyzed by mean survival time over 12 hours (MST12 h in a time-kill study. Results The time-kill studies indicated that the minimum inhibitory concentration (MIC of colistin (0.5 or 0.25 μg/mL completely killed all strains at 2 to 4 hours, but 0.5×MIC colistin showed no bactericidal activity. Meropenem (8 μg/mL, minocycline (1 μg/mL or rifampicin (0.06 μg/mL did not show bactericidal activity. However, combinations of colistin at 0.5×MIC (0.25 or 0.125 μg/mL with each of the above were synergistic and shown bactericidal activities against all test isolates. A combination of meropenem (16 μg/mL with minocycline (0.5×MIC, 4 or 2 μg/mL was synergitic to all test isolates, but neither showed bactericidal activity alone. The MST12 h values of drug combinations (either colistin- or minocycline-based combinations were significantly shorter than those of the single drugs (p Conclusions This study indicates that combinations of colistin/meropenem, colistin/rifampicin, colistin/minocycline and minocycline/meropenem are synergistic in vitro against XDR-AB strains.

Genetic relatedness and molecular characterization of multidrug resistant Acinetobacter baumannii isolated in central Ohio, USA

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Tadesse Daniel

2009-06-01

Full Text Available Abstract Background Over the last decade, nosocomial infections due to Acinetobacter baumannii have been described with an increasing trend towards multidrug resistance, mostly in intensive care units. The aim of the present study was to determine the clonal relatedness of clinical isolates and to elucidate the genetic basis of imipenem resistance. Methods A. baumannii isolates (n = 83 originated from two hospital settings in central Ohio were used in this study. Pulsed-field gel electrophoresis genotyping and antimicrobial susceptibility testing for clinically relevant antimicrobials were performed. Resistance determinants were characterized by using different phenotypic (accumulation assay for efflux and genotypic (PCR, DNA sequencing, plasmid analysis and electroporation approaches. Results The isolates were predominantly multidrug resistant (>79.5% and comprised of thirteen unique pulsotypes, with genotype VII circulating in both hospitals. The presence of blaOXA-23 in 13% (11/83 and ISAba1 linked blaOXA-66 in 79.5% (66/83 of clinical isolates was associated with high level imipenem resistance. In this set of OXA producing isolates, multidrug resistance was bestowed by blaADC-25, class 1 integron-borne aminoglycoside modifying enzymes, presence of sense mutations in gyrA/parC and involvement of active efflux (with evidence for the presence of adeB efflux gene. Conclusion This study underscores the major role of carbapenem-hydrolyzing class D β-lactamases, and in particular the acquired OXA-23, in the dissemination of imipenem-resistant A. baumannii. The co-occurrence of additional resistance determinant could also be a significant threat.

Degradation of dibenzofuran via multiple dioxygenation by a newly isolated Agrobacterium sp. PH-08.

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Le, T T; Murugesan, K; Nam, I-H; Jeon, J-R; Chang, Y-S

2014-03-01

To demonstrate the biodegradation of dibenzofuran (DF) and its structural analogs by a newly isolated Agrobacterium sp. PH-08. To assess the biodegradation potential of newly isolated Agrobacterium sp. PH-08, various substrates were evaluated as sole carbon sources in growth and biotransformation experiments. ESI LC-MS/MS analysis revealed the presence of angular degrading by-products as well as lateral dioxygenation metabolites in the upper pathway. The metabolites in the lower pathway also were detected. In addition, the cometabolically degraded daughter compounds of DF-related compounds such as BP and dibenzothiophene (DBT) in dual substrate degradation were observed. Strain PH-08 exhibited the evidence of meta-cleavage pathway as confirmed by the activity and gene expression of catechol-2,3-dioxygenase. Newly isolated bacterial strain, Agrobacterium sp. PH-08, grew well with and degraded DF via both angular and lateral dioxygenation as demonstrated by metabolites identified through ESI LC-MS/MS and GC-MS analyses. The other heterocyclic pollutants were also cometabolically degraded. Few reports have described the complete degradation of DF by a cometabolic lateral pathway. Our study demonstrates the novel results that the newly isolated strain utilized the DF as a sole carbon source and mineralized it via multiple dioxygenation. © 2013 The Society for Applied Microbiology.

DNA fingerprinting and antimicrobial susceptibility pattern of clinical and environmental Acinetobacter baumannii isolates: a multicentre study.

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Salimizand, Himen; Menbari, Shaho; Ramazanzadeh, Rashid; Khonsha, Masomeh; Saleh Vahedi, Mohammad

2016-08-01

The aims of this study were to establish antibiotic profile and the molecular epidemiology of Acinetobacter baumannii isolates, with considering the effectiveness of control infection measures across three hospitals in the Kurdistan, west part of Iran. Fifty-four A. baumannii isolates were collected from patients and environmental specimens. Antibiotic susceptibility patterns (Antibio-type) were evaluated for 17 different antibiotics and MIC for imipenem was done. Isolates were assessed for the presence of metallo-beta-lactamases (MBLs), class 1 and 2 integrons, and integrated gene cassettes and blaOXA-likefamilies genes. Repetitive-sequence-based PCR (REP-PCR) was done for analysing clonality and relativeness of isolates (REP-type). Antibiotic susceptibility patterns distinguished 11 distinct Antibio-types and REP-PCR showed three clusters with 20 subclusters, mostly belonged to two clonal subgroups, A1 and B1. blaOXA-51 and blaOXA-23 were detected in 100% (54/54) and 52% (28/54), respectively, while blaOXA-24-like and blaOXA-58 were not present in isolates. MBLs were not detected, but, however, high rate of imipenem resistance was observed (52%). MIC90 of imipenem was 16 mg/ml. Class 1 integrons were detected in 11% (6/54) of isolates followed by 24% (13/54) of class 2. Both classes of integron genes were detected in 15% (8/54) of isolates. Integrated gene cassettes were in low level (11% of class 1 harboring isolates). Two arrays of gene cassettes were revealed, dfrA5-like and dfrA17-aadA5. Infection control surveillance should be considered as a serious manner, even the superficial eradication of hospital acquired pathogens. MBL genes were not induced carbapenem resistance in studied hospital settings, but blaOXA-51 & 23 contributed in imipenem resistant. Integrons had a little share in resistance of A. baumannii isolates.

Imipenem Treatment Induces Expression of Important Genes and Phenotypes in a Resistant Acinetobacter baumannii Isolate.

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Dhabaan, Ghulam Nasser; AbuBakar, Sazaly; Cerqueira, Gustavo Maia; Al-Haroni, Mohammed; Pang, Sui Ping; Hassan, Hamimah

2015-12-14

Acinetobacter baumannii has emerged as a notorious multidrug-resistant pathogen, and development of novel control measures is of the utmost importance. Understanding the factors that play a role in drug resistance may contribute to the identification of novel therapeutic targets. Pili are essential for A. baumannii adherence to and biofilm formation on abiotic surfaces as well as virulence. In the present study, we found that biofilm formation was significantly induced in an imipenem-resistant (Imp(r)) strain treated with a subinhibitory concentration of antibiotic compared to that in an untreated control and an imipenem-susceptible (Imp(s)) isolate. Using microarray and quantitative PCR analyses, we observed that several genes responsible for the synthesis of type IV pili were significantly upregulated in the Imp(r) but not in the Imp(s) isolate. Notably, this finding is corroborated by an increase in the motility of the Imp(r) strain. Our results suggest that the ability to overproduce colonization factors in response to imipenem treatment confers biological advantage to A. baumannii and may contribute to clinical success. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

SHORT COMMUNICATION: Non-Fermenters in Human Infections with Special Reference to Acinetobacter Species in a Tertiary Care Hospital from North Karnataka, India

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Prashant K. Parandekar

2012-01-01

Full Text Available Background: Non-fermenters are a group of aerobic non-spore forming gram negative bacilli that are either incapable of utilizingcarbohydrates as a source of energy or degrade them via oxidative rather than fermentative pathway. These are increasingly been reported from the cases of nosocomial infections. Aims and Objectives: This study was undertaken aiming to identify, characterize all nonfermenters and further study of Acinetobacterisolates. Materials and Methods: A total 116 non-fermenters isolated from various specimens obtained from the patients in tertiarycare hospital. Gram negative bacilli which failed to produce acid on Triple Sugar Iron Agar (TSI were identified by employing battery oftests. The Acinetobacter isolates were further speciated and antimicrobial susceptibility testing done by Kirby Bauer disc diffusion technique. Results: Non-fermenters isolated were Pseudomonas aerugionsa (69.8%, Acinetobacter species (18.9%,Stenotrophomonas maltophilia (4.3%, Burkholderia cepacia (3.4%, Alcaligenes fecalis (1.7% and Pseudomonas fluorescens (1.7%. Most of the isolates showed susceptibility to imipenem (86.3% whereasnone of the isolates were sensitive to cephalexin and co-trimoxazole. Conclusion: This study highlights that, after Pseudomonas aeruginosa, Acinetobacter species is the most common non-fermenter. Majority of the isolates of Acinetobacter Species were ofnosocomial origin and were multidrug resistant, which underlines the importance of proper vigilance of these infections in hospital setting.

Drug resistance patterns of acinetobacter baumannii in makkah, saudi arabia

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Khan, M.A.; Ashshi, A.M.; Mahomed, M.F.

2012-01-01

Background: Acinetobacter baumannii causes infections of respiratory, urinary tract, blood stream and surgical sites. Its clinical significance has increased due to its rapidly developing resistance to major groups of antibiotics used for its treatment. There is limited data available on antimicrobial susceptibility of A. baumannii from Saudi Arabia. Objectives: To determine the patterns of drug resistance of Acinetobacter baumannii and predisposing factors for its acquisition.Subjects and Methods: In this descriptive study, 72 hospitalized patients infected with A baumannii were studied. The clinical and demographic data of the patients were collected using a predesigned questionnaire. Isolation and identification of A.baumannii from all clinical specimens were done using standard microbiological methods. Antibiotic susce ptibility testing was performed by disk diffusion method recommended by Clinical Laboratory Standards Institute. Results: Majority of the isolates (61.1%) were from respiratory tract infections. A.baumannii isolates showed high drug resistance to piperacil lin (93.1%), aztreonam (80.5%), ticarcillin, ampicillin, and tetracycline (76.4%, each) and cefotaxime (75%). Only amikacin showed low rate of resistance compared to other antibiotics (40.3%). About 36% patients had some underlying diseases with diabetes mellitus (11%) being the predominant underlying disease. Conclusions: High antimicrobial resistance to commonly used antibiotics was seen against A.baumannii isolates. Only amikacin was most effective against it. (author)

Acinetobacter baumannii-Infected Vascular Catheters Collected from Horses in an Equine Clinic

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Vaneechoutte, Mario; Devriese, Luc A.; Dijkshoorn, Lenie; Lamote, Benedicte; Deprez, Piet; Verschraegen, Gerda; Haesebrouck, Freddy

2000-01-01

Acinetobacter baumannii was isolated from tips clipped from seven intravenous jugular catheters collected from horses in the Ghent University equine clinic. They originated from seven different horses. Three of the seven showed evidence of local infection.

Microbiological features and clinical impact of the type VI secretion system (T6SS) in Acinetobacter baumannii isolates causing bacteremia.

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Kim, Jungok; Lee, Ji-Young; Lee, Haejeong; Choi, Ji Young; Kim, Dae Hun; Wi, Yu Mi; Peck, Kyong Ran; Ko, Kwan Soo

2017-10-03

We investigated the genetic background and microbiological features of T6SS-positive Acinetobacter baumannii isolates and clinical impact of the T6SS in patients with A. baumannii bacteremia. One hundred and 62 A. baumannii isolates from patients with bacteremia in 2 tertiary-care hospitals in Korea were included in this study. Approximately one-third (51/162, 31.5%) of the A. baumannii clinical isolates possessed the hcp gene, and the hcp-positive isolates were found in several genotypes in multilocus sequence typing. The expression and secretion of Hcp protein varied among the clinical isolates. A. baumannii isolates with detectable Hcp secretion (T6SS+) could better outcompete Escherichia coli compared with T6SS- isolates, including hcp-negative and inactivated hcp-positive isolates. In addition, T6SS+ isolates showed higher biofilm-forming activity and better survival in the presence of normal human serum than the T6SS- isolates. T6SS+ isolates were more frequently detected in patients with catheter-related bloodstream infection, haematopoietic stem cell transplant recipients, and patients receiving immunosuppressive agents. However, T6SS was not a prognostic factor for mortality. Our results suggest that the T6SS of A. baumannii is associated with virulence and contributes to infections in immunocompromised patients and those with implanted medical devices.

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

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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. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

ISAba1 Regulated OXA-23 Carbapenem Resistance in Acinetobacter baumannii Strains in Durban, South Africa.

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Agoba, Esther Eyram; Govinden, Usha; Peer, Abdool Kader Cassim; Osei Sekyere, John; Essack, Sabiha Yusuf

2018-03-20

This study investigated the molecular mechanisms of resistance to carbapenems and cephalosporins in 24 consecutive, multidrug-resistant Acinetobacter baumannii (MDRAB) isolates collected between January and April 2015 by a private sector laboratory in Durban, South Africa. All isolates were resistant to all carbapenems tested. bla OXA-23 and bla OXA-51 genes were found in 23 isolates, while bla OXA-24 , bla OXA-48 , and bla OXA-58 were absent in all isolates. The most prevalent extended-spectrum β-lactamase was TEM-116 (92%). bla ADC was present in 83.3% of isolates, of which two were new variants with three and five amino acid differences compared to Acinetobacter-derived cephalosporinase (ADC)-1, the first at positions 64E → K, 341N → T, and 342R → G and the second at positions 24G → D, 167S → P, 283R → F, 341N → T, and 342R → G, respectively. All isolates were negative for bla PER , bla CMY , bla GES , bla KPC , bla CTX-M , and bla SHV . Metallo-β-lactamase IMP and VIM were absent in all isolates, and NDM-1 was present in 1 isolate. ISAba1 was located upstream bla OXA-23 in all isolates and upstream bla ADC (30, 78, 79, 87 and the ADC variants) in 54.2% of the ADC-carrying isolates. None of the isolates had ISAba1 inserted upstream bla OXA-51 gene. Four isolates were clonally related and showed two clusters (A and B), while 20 isolates remained unclustered. There was no direct relationship between the clusters and the hospitals they were isolated from. This study reports the first NDM-1-producing carbapenem resistant Acinetobacter baumannii isolate in South Africa and highlights the presence of OXA-23, the known ADCs (ADC-30, ADC-78, ADC-79, and ADC-87), and two new ADC variants associated with ISAba1 from the private health sector in Durban, South Africa. The complexity and diversity of MDRAB severely limit treatment options.

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

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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.

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

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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. Copyright © 2016. Published by Elsevier Ltd.

Correlation between ability of biofilm formation with their responsible genes and MDR patterns in clinical and environmental Acinetobacter baumannii isolates.

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Bardbari, Ali Mohammadi; Arabestani, Mohammad Reza; Karami, Manoochehr; Keramat, Fariba; Alikhani, Mohammad Yousef; Bagheri, Kamran Pooshang

2017-07-01

Acinetobacter baumannii potential to form biofilm and exhibit multiple antibiotic resistances may be responsible in its survival in hospital environment. Accordingly, our study was aimed to determine the correlation between ability of biofilm formation and the frequency of biofilm related genes with antibiotic resistance phenotypes, and also the categorization of their patterns in clinical and environmental isolates. A total of 75 clinical and 32 environmental strains of the A. baumannii were collected and identified via API 20NE. Antibiotic susceptibility was evaluated by disk diffusion and microdilution broth methods. Biofilm formation assay was performed by microtiter plate method. OXA types and biofilm related genes including Bla OXA-51 , Bla OXA-23 , Bla OXA-24 , Bla OXA-58 , bap, bla PER-1 , and ompA were amplified by PCR. The rate of MDR A. baumannii in clinical isolates (100%) was higher than environmental (81.2%) isolates (p baumannii isolates was associated with biofilm formation. There was a significant correlation between multiple drug resistance and biofilm formation. The clinical isolates had a higher ability to form strong biofilms compared to the environmental samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro activities of carbapenems in combination with amikacin, colistin, or fosfomycin against carbapenem-resistant Acinetobacter baumannii clinical isolates.

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Singkham-In, Uthaibhorn; Chatsuwan, Tanittha

2018-01-31

Carbapenem-resistant Acinetobacter baumannii clinical isolates (n=23) were investigated for carbapenem resistance mechanisms and in vitro activities of carbapenems in combination with amikacin, colistin, or fosfomycin. Major carbapenem resistance mechanism was OXA-23 production. The vast majority of these isolates were OXA-23-producing A. baumannii ST195 and ST542, followed by novel STs, ST1417, and ST1423. The interuption of carO by a novel insertion sequence, ISAba40, was found in two isolates. The combinations of imipenem and fosfomycin, meropenem and amikacin, imipenem and amikacin, and imipenem and colistin were synergistic against carbapenem-resistant A. baumannii by 65.2%, 46.2%, 30.8%, and 17.4%, respectively. Surprisingly, the combination of imipenem and fosfomycin was the most effective in this study against A. baumannii, which is intrinsically resistant to fosfomycin. Imipenem and fosfomycin inhibit cell wall synthesis; therefore, fosfomycin may be an adjuvant and enhance the inhibition of cell wall synthesis of carbapenem-resistant A. baumannii when combined with imipenem. Copyright © 2018. Published by Elsevier Inc.

Limited genetic diversity and extensive antimicrobial resistance in clinical isolates of Acinetobacter baumannii in north-east Iran.

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Farsiani, Hadi; Mosavat, Arman; Soleimanpour, Saman; Nasab, Mahbobeh Naderi; Salimizand, Himen; Jamehdar, Saeid Amel; Ghazvini, Kiarash; Aryan, Ehsan; Baghani, Ali-Asghar

2015-07-01

This study determined the mechanisms and patterns of antimicrobial resistance among the isolates obtained from different wards of a teaching hospital in the city of Mashhad in north-east Iran. Between January 2012 and the end of June 2012, 36 isolates of Acinetobacter baumannii were collected from different wards of Ghaem Hospital. Antimicrobial susceptibility testing and epsilometer testing (E-test) were performed. The genetic resistance determinants of A, B and D classes of β-lactamases, aminoglycoside modifying enzymes (AMEs), efflux pumps and ISAba1 elements were assessed by PCR. Repetitive extragenic palindromic element (REP)-PCR was performed to find the genetic relatedness of the isolates. Colistin was the most effective antibiotic of those tested, where all isolates were susceptible. E-test results revealed high rates of resistance to imipenem, ceftazidime and ciprofloxacin. The majority of isolates (97  %) were multidrug-resistant. OXA-51, OXA-23 and tetB genes were detected in all isolates, but OXA-58, IMP and tetA were not detected. The prevalence of OXA-24, bla(TEM), bla(ADC), bla(VIM) and adeB were 64, 95, 61, 64 and 86  %, respectively. ISAba1 was found to be inserted into the 5' end of OXA-23 in 35 isolates (97  %). Of the AMEs, aadA1 (89  %) was the most prevalent, followed by aphA1 (75  %). The band patterns reproduced by REP-PCR showed that 34 out of 36 isolates belonged to one clone and two singletons were identified. The results confirmed that refractory A. baumannii isolates were widely distributed and warned the hospital infection control team to exert strict measures to control the infection. An urgent surveillance system should be implemented.

Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry rapid detection of carbapenamase activity in Acinetobacter baumannii isolates

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Noha Abouseada

2017-01-01

Full Text Available Introduction: Carbapenamase-producing Acinetobacter baumannii are an increasing threat in hospitals and Intensive Care Units. Accurate and rapid detection of carbapenamase producers has a great impact on patient improvement and aids in implementation of infection control measures. Aim: In this study, we describe the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI TOF MS to identify carbapenamase-producing A. baumannii isolates in up to 3 h. Isolates and Methods: A total of 50 A. baumannii isolates (of which 39 were carabapenamase producers were tested using MALDI TOF MS. Isolates were incubated for 3 h with 0.25 mg/ml up to 2 mg/ml of imipenem (IMP at 37°C. Supernatants were analysed by MALDI TOF to analyse peaks corresponding to IMP (300 Da and an IMP metabolite (254 Da using UltrafleXtreme (Bruker Daltonics, Bremen, Germany. Results: All carbapenamase-producing isolates were evidenced by the disappearance or reduction in intensity of the 300 Da peak of IPM and the appearance of a 254 Da peak of the IPM metabolite. In isolates that did not produce carbapenamase, the IPM 300 Da peak remained intact. Conclusion: MALDI TOF is a promising tool in the field of diagnostic microbiology that has the ability to transfer identification and antimicrobial susceptibility testing time from days to hours.

Extrahuman Epidemiology of Acinetobacter baumannii in Lebanon

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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

Occurrence of bla genes encoding carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii from Intensive Care Unit in a tertiary care hospital.

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Subramaniyan, Jayanthi Siva; Sundaram, Jeya Meenakshi

2018-01-01

ICU shows increasing incidence of infection associated with the use of invasive procedures for the diagnostic purpose as well as the indiscriminate use of antibiotics. Pseudomonas aeruginosa and Acinetobacter species are "very successful" pathogen and the emergence of the Metallo-β-Lactamases (MBL) is becoming a therapeutic challenge. To isolate the Nonfermenting Gram negative bacilli from the ICU samples. To identify the metallo betalactamase producers and to detect the bla gene presence among the Pseudomonas aeruginosa and Acinetobacter baumannii . The Nonfermenting Gram negative bacilli isolates from the ICU samples were taken over for 5 years (2009-2014) in a tertiary care hospital. The isolates of Pseudomonas species and Acinetobacter species were confirmed by API analyser and processed according to standard procedures. Detection of the MBL producers were done by E strip method and subjected for bla gene detection by PCR method. In our study a total of 195 isolates of NFGNB were obtained from various ICU. Of these MBL producers, 26 % were Pseudomonas aeruginosa and 25 % were Acinetobacter baumannii . The subtypes of bla VIM MBL producing P.aeruginosa were 26%. The predominant gene coding for MBL activity in A.baumannii were found to be bla OXA gene 11.9%. The gene accession numbers were KF975367, KF975372. We have to control the development and dissemination of these superbugs among the ICU's.

The Prevalence of ESBL Isolates of Acinetobacter baumannii Using Pulsed-Field Gel Electrophoresis

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Parviz Mohajeri

2014-12-01

Full Text Available Background: Antibiotics such as fluoroquinolones are used for treating infections caused by Gram-negative bacteria, including Acinetobacter baumannii strains some time have extended-spectrum β-lactamase (ESBL, but ESBL production is rather rare. Resistance to fluoroquinolones antibiotics is mediated by lactamases and other mechanisms of resistance. The aim of the present study was to investigate of the prevalence of ESBL production and clonal relatedness of A. baumannii in Iran. Materials and Methods: A. baumannii isolates identified from patients at hospitals in Kermanshah, Iran, were studied. The double disk method was used for detection of ESBL production. The susceptibility to different antibiotics was determined by the disk diffusion method (CLSI. Clonal relatedness was determined by pulsed-field gel electrophoresis (PFGE and processed by Bionumerics 7.0 software. Statistical analyses were performed using SPSS-16.0. Results: This study showed high prevalence of resistance to ampicillin and cefpodoxim (98.1 and 92.3%. Fifty-two of the 84 isolates were identified as ESBL producers. Only colistin and tigecycline remained active against all isolates tested. The PFGE identified eight distinct pulsotypes: A (N=9, B (N=10, C (N=2, D (N=5, E (N=9, F (N=15, G (N=1 and H (N=1. The PFGE profiles A, B and F were believed to be endemic (specially clone F that was dominant across different wards of the hospitals and appeared to be endemic in the ICU, emergency, pediatric and infection area throughout the years. Conclusion: Early and timely detection of ESBL-producing A. baumannii clones is useful for preventing their spread within the hospital. PFGE analysis is helpful for detection of common strains in different wards and prevention of further spread of these pulsotypes to other hospital environment.

Effects of Carbapenem consumption on the prevalence of Acinetobacter infection in intensive care unit patients.

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Ogutlu, Aziz; Guclu, Ertugrul; Karabay, Oguz; Utku, Aylin Calica; Tuna, Nazan; Yahyaoglu, Mehmet

2014-01-09

The consumption of carbapenems has increased worldwide, together with the increase in resistant gram negative bacilli. Subsequently, the prevalence of carbapenem-resistant Acinetobacter infections has increased rapidly and become a significant problem particularly in intensive care unit patients. The aim of the present study was to evaluate the changes in the prevalence of Acinetobacter infection by restricting the consumption of carbapenems in intensive care unit patients. This study was conducted between May 1, 2011 and February 28, 2013. The amount of carbapenem consumption and the number of patients with multi-drug resistant Acinetobacter baumannii (MDRAB) isolates during the study period were retrospectively obtained from the records of the patients, who were hospitalized in the intensive care unit. The study period was divided into two periods named as: Carbapenem non-restricted period (CNRP) and carbapenem-restricted period (CRP). During CNRP, no restrictions were made on the use of carbapenems. During CRP, the use of carbapenems was not allowed if there was an alternative to carbapenems. Primary Endpoint: MDRAB infection after ICU admission. The definition of nosocomial infections related to Acinetobacter spp. was based on the criteria of the Center for Disease Control (CDC). The correlation between the amount of carbapenem consumption and the number of infections with MDRAB strains between the two periods were evaluated. During the study period, a total of 1822 patients' (1053 patients in CNRP and 769 patients in CRP) records were evaluated retrospectively. A total of 10.82 defined daily dose (DDD/100 ICU days) of anti-pseudomonal carbapenem were used in CNRP, and this figure decreased to 6.95 DDD/100 ICU days in CRP. In the 8-month CNRP, 42 (3.98%) MDRAB-related nosocomial infections were detected, and 14 (1.82%) infections were detected in CRP (p = 0.012). The prevalence of MDRAB strains isolated in the CNRP was 2.24-fold higher than the prevalence in

Isolation and Characterization of a Virulent Bacteriophage AB1 of Acinetobacter baumannii

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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

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

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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

Draft Genome Sequence of Acinetobacter johnsonii C6, an Environmental Isolate Engaging in Interspecific Metabolic Interactions

DEFF Research Database (Denmark)

Kaas, Rolf Sommer; Mordhorst, Hanne; Leekitcharoenphon, Pimlapas

2017-01-01

Acinetobacter johnsonii C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with Pseudomonas putida in biofilms. The draft genome of A. johnsonii C6 is 3.7 Mbp and was shaped by mobile genetic elements. It reveals genes facilitating the biodegrad......Acinetobacter johnsonii C6 originates from creosote-polluted groundwater and performs ecological and evolutionary interactions with Pseudomonas putida in biofilms. The draft genome of A. johnsonii C6 is 3.7 Mbp and was shaped by mobile genetic elements. It reveals genes facilitating...

OXA beta-lactamase-mediated carbapenem resistance in Acinetobacter baumannii

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S M Amudhan

2011-01-01

Full Text Available Objectives: Acinetobacter baumannii is a significant pathogen in health care settings. In recent years, an increase in carbapenem resistance among A. baumannii due to Ambler class B metallo-beta-lactamases or class D OXA carbapenamases has been reported. In this study we detected the presence of OXA carbapenamases and coproduction of metallo-beta-lactamases (blaVIM and blaIMP by phenotypic and genotypic methods in carbapenem resistant clinical isolates of Acinetobacter baumannii. Materials and Methods: A total of 116 consecutive, non-duplicate carbapenem resistant A. baumannii isolated from various clinical specimens were included in the study. The modified Hodge test and inhibitor potentiated disk diffusion tests were done for the screening of carbapenamase and metallo-beta-lactamase production, respectively. Polymerase chain reaction (PCR was performed for the detection of OXA (blaOXA 23 like, blaOXA 24 like, blaOXA-51 like and blaOXA-58 like genes and metallo-beta-lactamases (blaVIM and blaIMP genes. Gene sequencing was performed for representative isolates. Results: Among 116 A. baumannii, OXA genes were detected in 106 isolates. BlaOXA 51 like (n = 99 and blaOXA -23 like (n = 95 were the most common and they coexisted in 89 isolates. blaOXA-24 like gene was detected in two isolates of which one also carried blaOXA-51 like and blaOXA-58 like genes. The modified Hodge test was positive in 113 isolates. The metallo-beta-lactamase screening test was positive in 92 isolates. blavim was detected in 54 isolates of which 1 also carried the blaIMP gene. Conclusions: blaOXA-23 like and bla OXA 51 like genes are the most common types of OXA carbapenamases while the blaVIM type is the most common type of metallo-beta-lactamase contributing to carbapenem resistance in clinical isolates of A. baumannii. The coproduction of OXA and metallo-beta-lactamases is not an uncommon phenomenon in A. baumannii.

PER-8, a Novel Extended-Spectrum β-Lactamase PER Variant, from an Acinetobacter baumannii Clinical Isolate in Nepal.

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Tada, Tatsuya; Shrestha, Shovita; Shimada, Kayo; Ohara, Hiroshi; Sherchand, Jeevan B; Pokhrel, Bharat M; Kirikae, Teruo

2017-03-01

A novel PER-type extended-spectrum β-lactamase, PER-8, was identified in an Acinetobacter baumannii clinical isolate obtained in Nepal. The amino acid sequence of PER-8 has a substitution at position 39 (Gly to Glu) compared with that of PER-7. The k cat / K m ratio of PER-8 for aztreonam was lower than that of PER-7, while the k cat / K m ratio of PER-8 for imipenem was higher than that of PER-7. The genomic environment surrounding bla PER-8 was intI1 bla PSE-1 qacEDI sulI IS CR1-bla PER-8 gts sulI orfX on a 100-kb plasmid. Copyright © 2017 American Society for Microbiology.

In vitro evaluation of the susceptibility of Acinetobacter baumannii isolates to antiseptics and disinfectants: comparison between clinical and environmental isolates

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Sanae Lanjri

2017-04-01

Full Text Available Abstract Background This study aims to assess the susceptibility of Acinetobacter baumannii isolates to the antiseptics and disinfectants commonly used, and to the non-approved product. Methods This is a prospective study carried out from February to August 2015, in the Bacteriology department of Mohammed V Military Teaching hospital of Rabat on A.baumannii isolates collected from colonized and/or infected patients and environmental samples. The antiseptics and disinfectants susceptibility testing was assessed using the micromethod validated in our department. The antiseptics and disinfectants studied were: 70% ethyl alcohol, chlorhexidine, povidone-iodine, didecyldimethylammonium chloride and a commercial product which was presented as a hospital disinfectant (non-registered product. Results Povidone-iodine, 0.5% chlorhexidine digluconate, 70% ethyl alcohol and didecyl dimethyl ammonium chloride in combination with N- (3-aminopropyl -N-dodecylpropane-1, 3-diamine were effective against all the 81 A.baumannii isolates tested, and their logarithmic reduction ≥ 5 were observed in 100% of the isolates in their undiluted form. The strains isolated from patients were more resistant than environmental strains: at a dilution of ½ for 70% ethyl alcohol (37.77% vs 11.11%, p = 0.007 and at a dilution of 1/10 (100% vs 69.44%, p < 0.001 for povidone iodine. The non-registered product was ineffective with a resistance rate of 96.29% at a dilution of 1/50, 45.67% at a dilution of 1/10 and 13.58% in its purest form. Conclusion Our study revealed the effectiveness of the main disinfectants and antiseptics used in Morocco; three antiseptics tested were effective in their purest form against the 81 A.baumannii isolates. Regarding disinfectants, our results showed an efficacy of didecyl dimethyl ammonium at the recommended use concentration and in its purest form. This study emphasizes the need for using disinfectants and antiseptics in dilutions

First report of blaNDM-1-producing Acinetobacter baumannii isolated in Lebanon from civilians wounded during the Syrian war.

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Rafei, Rayane; Dabboussi, Fouad; Hamze, Monzer; Eveillard, Matthieu; Lemarié, Carole; Mallat, Hassan; Rolain, Jean-Marc; Joly-Guillou, Marie-Laure; Kempf, Marie

2014-04-01

The emergence of carbapenem-resistant Acinetobacter baumannii has been observed worldwide. We describe the first detection of A. baumannii carrying the blaNDM-1 gene in Lebanon, isolated from Syrian patients wounded during the civil war. Four carbapenem-resistant A. baumannii strains isolated in 2012 in the Tripoli Government Hospital, Lebanon, from civilians wounded during the Syrian war, were analysed. Susceptibility was determined by disk diffusion testing, and resistance to carbapenems was confirmed by Etest. The presence of blaOXA-23-like, blaOXA-24-like, blaOXA-58-like, blaOXA-143-like, and blaNDM was investigated by PCR. Clonal relationships were studied by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and blaOXA-51 sequence-based typing. All isolates harboured the blaNDM-1 gene and were negative for other tested carbapenemases. They all belonged to the sequence type 85 and formed a single cluster by PFGE. Finally, blaOXA-51-like gene sequencing revealed the presence of the blaOXA-94 variant in all four isolates. These findings show that Syria constitutes a reservoir for NDM-1-producing bacteria. These results also highlight the need for effective measures to stop the threatening spread of such strains. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Influence of regular reporting on local Pseudomonas aeruginosa and Acinetobacter spp. sensitivity to antibiotics on consumption of antibiotics and resistance patterns.

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Djordjevic, Z M; Folic, M M; Jankovic, S M

2017-10-01

Regular surveillance of antimicrobial resistance is an important component of multifaceted interventions directed at the problem with resistance of bacteria causing healthcare-associated infections (HAIs) in intensive care units (ICUs). Our aim was to analyse antimicrobial consumption and resistance among isolates of Pseudomonas aeruginosa and Acinetobacter spp. causing HAIs, before and after the introduction of mandatory reporting of resistance patterns to prescribers. A retrospective observational study was conducted between January 2011 and December 2015, at an interdisciplinary ICU of the Clinical Centre Kragujevac, Serbia. The intervention consisted of continuous resistance monitoring of all bacterial isolates from ICU patients and biannual reporting of results per isolate to prescribers across the hospital. Both utilization of antibiotics and density of resistant isolates of P. aeruginosa and Acinetobacter spp. were followed within the ICU. Resistance densities of P. aeruginosa to all tested antimicrobials were lower in 2015, in comparison with 2011. Although isolates of Acinetobacter spp. had lower resistance density in 2015 than in 2011 to the majority of investigated antibiotics, a statistically significant decrease was noted only for piperacillin/tazobactam. Statistically significant decreasing trends of consumption were recorded for third-generation cephalosporins, aminoglycosides and fluoroquinolones, whereas for the piperacillin/tazobactam, ampicillin/sulbactam and carbapenems, utilization trends were decreasing, but without statistical significance. In the same period, increasing trends of consumption were observed for tigecycline and colistin. Regular monitoring of resistance of bacterial isolates in ICUs and reporting of summary results to prescribers may lead to a significant decrease in utilization of some antibiotics and slow restoration of P. aeruginosa and Acinetobacter spp. susceptibility. © 2017 John Wiley & Sons Ltd.

Prevalence of metallo-beta-lactamase among Pseudomonas aeruginosa and Acinetobacter baumannii isolated from burn wounds and in vitro activities of antibiotic combinations against these isolates.

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Altoparlak, Ulku; Aktas, Ferda; Celebi, Demet; Ozkurt, Zulal; Akcay, Mufide N

2005-09-01

The prevalence of metallo-beta-lactamases (MBLs) produced by isolates of Pseudomonas aeruginosa and Acinetobacter baumannii and the activities of various antmicrobial combinations against MBL producer strains were investigated. During the period from June 2003 till July 2004, 120 P. aeruginosa and 9 A. baumannii nonduplicate isolates were obtained from burn wounds. Forty strains (37 P. aeruginosa, 3 A. baumannii) were selected because of resistance to carbapenems. Screening for MBL production was performed in the latter isolates by the combined disk method which depends on comparing the zones given by disks containing imipenem with and without ethylenediaminetetraacetic acid (EDTA). Of imipenem resistant P. aeruginosa strains, 21 and 1 of A. baumannii were found metallo-beta-lactamase producers. Disk approximation studies were then performed to test for in vitro activities of various antimicrobial combinations. For a total of 21 P. aeruginosa strains, synergy was demonstrated predominantly by ciprofloxacin in combination with ceftazidime and imipenem, by ofloxacin in combination with astreonam. Against MBL producer A. baumannii strain, synergy was detected only with imipenem-ofloxacin combination. None of the combinations were antagonistic. These results suggest that MBL producing P. aeruginosa and A. baumanni strains have been introduced into burn centers, and to prevent the further spread of MBL producers, it is essential for carbapenem resistant isolates to be screened for MBLs.

Reservoirs of Non-baumannii Acinetobacter Species

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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. PMID:26870013

Multidrug‑resistant acinetobacter infection and their susceptibility ...

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Results: Major infections found in different medical wards, surgical wards and ICU were due to Acinetobacter baumannii (74.02%), A. lowfii (14.2%), A. haemolyticus (7.79%), A. junii (3.8%) among Acinetobacter spices. Acinetobacter showed increased resistant against majority of commercially available drugs imipenem ...

Three distinct clones of carbapenem-resistant Acinetobacter baumannii with high diversity of carbapenemases isolated from patients in two hospitals in Kuwait

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N.A. Al-Sweih

2012-02-01

Full Text Available Summary: Objectives: This study was undertaken to investigate the clonal relatedness of multidrug-resistant (MDR Acinetobacter baumannii isolates collected from patients in two teaching hospitals in Kuwait. Materials and methods: Clinically significant consecutive isolates of A. baumannii obtained from patients in the Mubarak (36 and Adan (58 hospitals over a period of 6 months were studied. These isolates were identified using molecular methods, and their antimicrobial susceptibility was determined by the Etest method. The mechanism of resistance to carbapenem was investigated by PCR, and pulsed-field gel electrophoresis (PFGE was used to determine the clonal relatedness of MDR isolates. Results: Of the 94 isolates investigated, 80 (85.1% were multidrug resistant (MDR. The A. baumannii PFGE clone A and subclone A1 were the most prevalent in patients infected with MDR isolates. Fifty-five (94.8% and 15 (41.7% of the MDR isolates from the Adan and Mubarak hospitals, respectively, belonged to PFGE clone A; isolates in this group showed higher resistance rates to antibiotics than isolates form other groups. Of the 94 isolates, 40 (42.6% were resistant to either imipenem or meropenem or to both (CRAB. Most CRAB isolates (29/40 or 72.5% carried bla genes, which code for MBL (VIM-2 and IMP-1 enzymes. Two isolates harbored blaOXA-23. Conclusion: Three distinct clones of CRAB were isolated, providing evidence of a high diversity of carbapenemases among our geographically related isolates. Keywords: MDR A. baumannii, Genotypes, bla genes, Kuwait hospitals

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

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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-bla OXA-23 and ISAba1-bla ADC 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 bla OXA-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.

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

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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. Keywords: Acinetobacter baumannii, Multi-drug resistance, Paediatric

Comprehensive study to investigate the role of various aminoglycoside resistance mechanisms in clinical isolates of Acinetobacter baumannii.

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Sheikhalizadeh, Vajihe; Hasani, Alka; Ahangarzadeh Rezaee, Mohammad; Rahmati-Yamchi, Mohammad; Hasani, Akbar; Ghotaslou, Reza; Goli, Hamid Reza

2017-02-01

Therapeutic resistance towards most of the current treatment regime by Acinetobacter baumannii has reduced the prescribing antibiotic pattern and option is being re-shifted towards more toxic agents including aminoglycosides. The present investigation aimed at to study various mechanisms towards aminoglycoside non-susceptibility in clinical isolates of A. baumannii. The bacteria were subjected to genetic basis assessment for the presence of aminoglycoside modifying enzymes (AME), 16S rRNA methylase encoding genes and relative expression of AdeABC and AbeM efflux pumps in relation to their susceptibility to five aminoglycosides. When isolates were subjected to typing by repetitive extragenic palindromic (REP) PCR, isolates could be separated into thirteen definite clones. The majority of isolates (94%) were positive for AME encoding genes. Possession of ant(2')-Ia correlated with non-susceptibility towards gentamicin, amikacin, kanamycin, tobramycin; while, presence of aph(3')-VIa attributed to resistance towards amikacin, kanamycin; possession of aac(3')-Ia allied with non-susceptibility to amikacin, tobramycin and presence of aac(3')IIa correlated with kanamycin non-susceptibility. Presence of armA was detected in 34.4%, 34.2%, 29.2%, 40.3%, and 64.2% of isolates showing non-susceptibility to gentamicin, amikacin, kanamycin, tobramycin and netilmicin, respectively. No isolates were found to carry rmtB or rmtC. Amikacin non-susceptibility in comparison to other aminoglycosides correlated with over production of adeB. Overall, the results represented a definitive correlation between presence of AME encoding genes as well as armA and resistance of A. baumannii towards aminoglycosides. On the other hand, the up-regulation of AdeABC and AbeM systems was found to have only the partial role in development of aminoglycoside resistance. Copyright © 2016 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All

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

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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 bla OXA-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 bla OXA-23-like including two that also harbored bla OXA-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 motility

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

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Priyendu Asim

2016-01-01

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

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

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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.

Detection of Ambler class A, B and D ß-lactamases among Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates from burn patients.

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Hakemi Vala, M; Hallajzadeh, M; Hashemi, A; Goudarzi, H; Tarhani, M; Sattarzadeh Tabrizi, M; Bazmi, F

2014-03-31

In this study, we evaluated the existence of classes A, B and D ß-lactamases among Pseudomonas aeruginosa (P.aeruginosa) and Acinetobacter baumannii (A.baumannii) strains isolated from burn patients in Tehran during the years 2012 and 2013. From these strains, the frequency of MBL (metallo-beta-lactamase) and ESBL (extended-spectrum beta-lactamase) producers were evaluated using CDDT (Combined Disk Diffusion Tests). The prevalence of some related genes, including blaIMP, blaVIM, blaSPM, blaKPC, blaGIM, blaDIM, blaBIC, blaOXA-48, blaCTX-M-15 and blaNDM genes, was evaluated using PCR and sequencing methods. Of the 75 non-fermenter isolates, 47 P.aeruginosa and 28 A.baumannii were isolated and identified. A high rate of resistance to common antibiotics was detected among A.baumannii isolates in particular, showing 100% resistance to 9 tested antibiotics. CDDT showed that 21 (28%) and 25 (34.25%) of the non-fermenter isolates were ESBL and MBL producers respectively. The prevalence of blaCTX-M-15 and blaIMP genes among the 75 non-fermenter isolates was 7 (9.3%) and 1 (1.3%), respectively. Fortunately, no other genes were detected in either of the non-fermenters. The mortality rate due to MBL-producing isolates was 5 (20%). This study showed specific resistance genes exist among some MBL and ESBL gram-negative non-fermenters which were isolated from burn patients in Tehran.

Xylanase production by a newly isolated Aspergillus niger SS7 in submerged culture.

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Bakri, Yasser; Al-Jazairi, Manal; Al-Kayat, Ghassan

2008-01-01

Xylanase production by a newly isolated Aspergillus niger SS7 was studied in submerged culture. The optimum initial pH for xylanase production was found to be 7.0. Different agricultural and industrial wastes were evaluated for their ability to induce xylanase production by this isolate. The best xylanase production (293.82 IU/ml) was recorded at 3% (w/v) corn cob hulls after 120 h of incubation. The Aspergillus niger SS7 isolate grown in a simple medium, proved to be a promising microorganism for xylanase production.

Endemic Acinetobacter baumannii in a New York hospital.

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Scott A Weisenberg

Full Text Available 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.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.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.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.

Endophthalmitis caused by Acinetobacter baumanni: a case series.

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Roy, R; Panigrahi, P; Malathi, J; Pal, S S; Nandi, K; Patil, A; Nigam, E; Arora, V

2013-03-01

To profile the etiology, clinical outcomes and drug sensitivity patterns in endophthalmitis caused by Acinetobacter baumanni. Retrospective analysis of all the cases of Acinetobacter baumanni endophthalmitis presenting to tertiary referral care ophthalmic hospital in Eastern India from January 2009 to December 2011 were done. A total of four cases were included in the study. Out of the four cases one was post traumatic and the rest were post cataract surgery. All the cases underwent vitreoretinal surgical intervention followed by intravitreal antibiotics. A. Baumanni was isolated from vitreous in all the cases. Among all the drugs tested bacteria were found sensitive to ciprofloxacin (100 %) whereas all tested resistant to ceftazidime. Out of the four cases one had to be eviscerated, another developed retinal detachment post vitrectomy, one was phthisical at final followup, and only one patient achieved a vision of 20/200 with clear media and attached retina at final visit. A. Baumanni is a very rare cause of endophthalmitis with poor visual and anatomical outcomes. Ciprofloxacin should be considered as first the line intravitreal antibiotic.

Distribution of different efflux pump genes in clinical isolates of multidrug-resistant Acinetobacter baumannii and their correlation with antimicrobial resistance.

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Lin, Ming-Feng; Lin, Yun-You; Tu, Chi-Chao; Lan, Chung-Yu

2017-04-01

Efflux pumps are one of the major mechanisms of antimicrobial resistance in Acinetobacter baumannii. This study aimed to understand the distribution of different types of pump genes in clinical isolates of multidrug-resistant A. baumannii (MDRAB) and to reveal the relationship between their presence and expression with antimicrobial resistance. MDRAB isolates were collected from five hospitals in Taiwan. Different categories of pump genes, including adeB, adeJ, macB, abeM, abeS, emrA-like, emrB-like, and craA, were chosen, and their presence in the collected isolates was determined. Three induced resistant strains of A. baumannii ATCC 17978 to tigecycline, imipenem, and amikacin were also included. The expressions of the selected pump genes were determined using quantitative reverse transcription-polymerase chain reaction. Twenty-one MDRAB clinical isolates were obtained from five hospitals. All of the studied pump genes were present in the collected MDRAB isolates except one isolate that lacked the emrA-like gene. The gene expression of these efflux pumps was variable among the strains. The upregulation of the adeB, adeJ, and macB genes was responsible for tigecycline resistance, and the increased abeS expression was strongly related to amikacin resistance. Of all the antibiotics studied, tigecycline was the strongest inducer of gene expression for many efflux pumps in A. baumannii. Efflux pump genes are universally present in the collected clinical MDRAB isolates. The upregulation of the adeB, adeJ, macB and abeS genes is more related with antibiotic resistance. Copyright © 2015. Published by Elsevier B.V.

Acinetobacter Species Infections among Navy and Marine Corps Beneficiaries: 2014 Annual Report

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2015-07-20

microbiology data were used to identify Acinetobacter cases. These isolates were matched to three databases. Microbiology records were matched to...Data Record (SIDR) database to determine exposure associations within the healthcare system. Microbiology records were matched to the Defense...that they could establish a community reservoir. Veterinary nosocomial spread has been described among animals, mainly in veterinary hospital intensive

Single-step selection of drug resistant Acinetobacter baylyi ADP1 mutants reveals a functional redundancy in the recruitment of multidrug efflux systems.

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Anthony J Brzoska

Full Text Available Members of the genus Acinetobacter have been the focus recent attention due to both their clinical significance and application to molecular biology. The soil commensal bacterium Acinetobacter baylyi ADP1 has been proposed as a model system for molecular and genetic studies, whereas in a clinical environment, Acinetobacter spp. are of increasing importance due to their propensity to cause serious and intractable systemic infections. Clinically, a major factor in the success of Acinetobacter spp. as opportunistic pathogens can be attributed to their ability to rapidly evolve resistance to common antimicrobial compounds. Whole genome sequencing of clinical and environmental Acinetobacter spp. isolates has revealed the presence of numerous multidrug transporters within the core and accessory genomes, suggesting that efflux is an important host defense response in this genus. In this work, we used the drug-susceptible organism A. baylyi ADP1 as a model for studies into the evolution of efflux mediated resistance in genus Acinetobacter, due to the high level of conservation of efflux determinants across four diverse Acinetobacter strains, including clinical isolates. A single exposure of therapeutic concentrations of chloramphenicol to populations of A. baylyi ADP1 cells produced five individual colonies displaying multidrug resistance. The major facilitator superfamily pump craA was upregulated in one mutant strain, whereas the resistance nodulation division pump adeJ was upregulated in the remaining four. Within the adeJ upregulated population, two different levels of adeJ mRNA transcription were observed, suggesting at least three separate mutations were selected after single-step exposure to chloramphenicol. In the craA upregulated strain, a T to G substitution 12 nt upstream of the craA translation initiation codon was observed. Subsequent mRNA stability analyses using this strain revealed that the half-life of mutant craA mRNA was significantly

Molecular characterization of extended-spectrum beta-lactamases (ESBLs) produced by clinical isolates of Acinetobacter baumannii in Saudi Arabia.

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Alyamani, Essam J; Khiyami, Mohamed A; Booq, Rayan Y; Alnafjan, Basel M; Altammami, Musaad A; Bahwerth, Fayez S

2015-08-20

Acinetobacter baumannii is a common opportunistic pathogen that causes major nosocomial infections in hospitals. In this study, we hypothesized a high prevalence of A. baumanni ESBL (extended-spectrum beta-lactamase) among all collected isolates. A. baumannii isolates (n = 107) from ICU (Intensive care unit) of local hospitals in Makkah were phenotypically and genotypically characterized. The identity and antibiotic susceptibility of A. baumannii strains were determined using the Vitek-2 system. The identified ESBL producers were further analyzed by PCR and sequencing followed by MLST typing. bla TEM , bla SHV , and the bla CTX-M-group genes 1, 2, 8, 9, and 25 were investigated. Furthermore, bla OXA51-like and bla OXA23-like genes were also examined in the carbapenem-resistant A. baumannii isolates. Our data indicated a high prevalence of A. baumannii ESBL producers among the collected strains. Of the 107 A. baumannii isolates, 94 % were found to be resistant to cefepime and ceftazidime, and aztreonam using the Vitek 2 system. The genes detected encoded TEM, OXA-51-like and OXA-23-like enzymes, and CTX-M-group proteins 1, 2, 8, 9, and 25. MLST typing identified eight sequence type (ST) groups. The most dominant STs were ST195 and ST557 and all of them belong to worldwide clonal complex (CC) 2. This study has shown that there is a high prevalence of antimicrobial resistance in A. baumannii. The diversity of STs may suggest that new ESBL strains are constantly emerging. The molecular diversity of the ESBL genes in A. baumannii may have contributed to the increased antimicrobial resistance among all isolates.

Antimicrobial activity of the imipenem/rifampicin combination against clinical isolates of Acinetobacter baumannii grown in planktonic and biofilm cultures.

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Wang, Yang; Bao, Wanguo; Guo, Na; Chen, Haiying; Cheng, Wei; Jin, Kunqi; Shen, Fengge; Xu, Jiancheng; Zhang, Qiaoli; Wang, Chao; An, Yanan; Zhang, Kaiyu; Wang, Feng; Yu, Lu

2014-12-01

To investigate the antimicrobial activity of imipenem and rifampicin alone and in combination against clinical isolates of Acinetobacter baumannii grown in planktonic and biofilm cultures. Minimum inhibitory concentrations were determined for each isolate grown in suspension and in biofilm using a microbroth dilution method. Chequerboard assays and the agar disk diffusion assay were used to determine synergistic, indifferent or antagonistic interactions between imipenem and rifampicin. We used the tissue culture plate method for A. baumannii biofilm formation to measure the percentage of biofilm inhibition and the amount of extracellular DNA after the treatment. To understand the synergistic mechanisms, we conducted hydroxyl radical formation assays. The results were verified by confocal laser scanning microscopy. Imipenem and rifampicin showed effective antimicrobial activity against suspensions and biofilm cultures of A. baumannii, respectively. Synergistic antimicrobial effects between imipenem and rifampicin were observed in 13 and 17 of the 20 clinical isolates when in suspension and in biofilms, respectively. Imipenem and rifampicin alone and in combination generated hydroxyl radicals, which are highly reactive oxygen forms and the major components of bactericidal agents. Furthermore, treatment with imipenem and rifampicin individually or in combination has obvious antibiofilm effects. The synergistic activity of imipenem and rifampicin against clinical isolates of A. baumannii (in suspension and in biofilms) was observed in vitro. Therefore, we conclude that imipenem combined with rifampicin has the potential to be used as a combinatorial therapy for the treatment of infectious diseases caused by A. baumannii.

Emission of extensively-drug-resistant Acinetobacter baumannii from hospital settings to the natural environment.

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Seruga Music, M; Hrenovic, J; Goic-Barisic, I; Hunjak, B; Skoric, D; Ivankovic, T

2017-08-01

Acinetobacter baumannii is a leading emerging pathogen that is frequently recovered from patients during hospital outbreaks. The role of environmental A. baumannii reservoirs is therefore of great concern worldwide. To investigate the connection between A. baumannii causing hospital outbreaks and environmental isolates from hospital wastewater, urban sewage and river water as the final natural recipient of wastewaters. Clinical isolates from patients with hospital-acquired pneumonia and environmental isolates from water were collected during a two-month monitoring period. Recovery of A. baumannii was performed using CHROMagar Acinetobacter plates, incubated at 42°C for 48 h. Identification was performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and analyses of rpoB gene. The antibiotic resistance profiles were interpreted according to criteria given for clinical isolates of A. baumannii. The sequence types (ST) were retrieved by multi-locus sequence typing. Fourteen of 19 isolates recovered from patients, hospital wastewaters, urban sewage and river water belonged to ST-195. The remaining five isolates recovered from patients and river water were assigned to ST-1421. All isolates showed very strong relatedness and clustered into CC92, which corresponds to IC2. All isolates were non-susceptible to at least one agent in all but two or fewer antimicrobial categories, and thus were classified as 'extensively-drug-resistant' (XDR). Heteroresistance to colistin was found in two isolates from hospital wastewater. Close relatedness of clinical and environmental isolates suggests the emission of XDR A. baumannii via the untreated hospital wastewater in the natural environment. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery

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Dong, Hao; Xia, Wenjie; Dong, Honghong; She, Yuehui; Zhu, Panfeng; Liang, Kang; Zhang, Zhongzhi; Liang, Chuanfu; Song, Zhaozheng; Sun, Shanshan; Zhang, Guangqing

2016-01-01

Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9, and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR. PMID:27872613

Rhamnolipids produced by indigenous Acinetobacter junii from petroleum reservoir and its potential in enhanced oil recovery

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Hao Dong

2016-11-01

Full Text Available Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS. The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C26H48O9, C28H52O9 and C32H58O13. The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

Rhamnolipids Produced by Indigenous Acinetobacter junii from Petroleum Reservoir and its Potential in Enhanced Oil Recovery.

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Dong, Hao; Xia, Wenjie; Dong, Honghong; She, Yuehui; Zhu, Panfeng; Liang, Kang; Zhang, Zhongzhi; Liang, Chuanfu; Song, Zhaozheng; Sun, Shanshan; Zhang, Guangqing

2016-01-01

Biosurfactant producers are crucial for incremental oil production in microbial enhanced oil recovery (MEOR) processes. The isolation of biosurfactant-producing bacteria from oil reservoirs is important because they are considered suitable for the extreme conditions of the reservoir. In this work, a novel biosurfactant-producing strain Acinetobacter junii BD was isolated from a reservoir to reduce surface tension and emulsify crude oil. The biosurfactants produced by the strain were purified and then identified via electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS). The biosurfactants generated by the strain were concluded to be rhamnolipids, the dominant rhamnolipids were C 26 H 48 O 9 , C 28 H 52 O 9 , and C 32 H 58 O 13 . The optimal carbon source and nitrogen source for biomass and biosurfactant production were NaNO 3 and soybean oil. The results showed that the content of acid components increased with the progress of crude oil biodegradation. A glass micromodel test demonstrated that the strain significantly increased oil recovery through interfacial tension reduction, wettability alteration and the mobility of microorganisms. In summary, the findings of this study indicate that the newly developed BD strain and its metabolites have great potential in MEOR.

Characterization of resistance mechanisms and genetic relatedness of carbapenem-resistant Acinetobacter baumannii isolated from blood, Italy.

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Migliavacca, Roberta; Espinal, Paula; Principe, Luigi; Drago, Monica; Fugazza, Giulia; Roca, Ignasi; Nucleo, Elisabetta; Bracco, Silvia; Vila, Jordi; Pagani, Laura; Luzzaro, Francesco

2013-02-01

The aim of this study was to characterize the resistance mechanisms and genetic relatedness of 21 carbapenem-resistant Acinetobacter baumannii blood isolates collected in Italy during a 1-year multicenter prospective surveillance study. Genes coding for carbapenemase production were identified by polymerase chain reaction (PCR) and sequencing. Pulsed-field gel electrophoresis (PFGE), multiplex PCRs for group identification, and multilocus sequence typing (MLST) were used to determine genetic relationships. Carbapenem resistance was consistently related to the production of oxacillinases, mostly the plasmid-mediated OXA-58 enzyme. Strains producing the OXA-23 enzyme (chromosomally mediated) were also detected. Seven PFGE clones were identified, some of which being related to international (ICL- I and ICL-II) or national clonal lineages. Multiplex PCRs identified 4 different groups (group 2 being dominant), further distinguishable in 6 sequence types by MLST. The heterogeneity of profiles highlights the diffusion of international and national clonal lineages in Italy. Continuous surveillance is needed for monitoring the spread of these worrisome strains equipped with multiple drug resistance mechanisms. Copyright © 2013 Elsevier Inc. All rights reserved.

Drug-resistant post-neurosurgical nosocomial Acinetobacter ...

African Journals Online (AJOL)

Drug-resistant post-neurosurgical nosocomial Acinetobacter baumannii meningitis in two Iranian hospitals. ... Vol 11, No 17 (2012) >. Log in or Register to get access to full text downloads. ... Acinetobacter baumannii may cause meningitis and ventriculitis, particularly after head trauma and/or neurosurgery. The rate of ...

Identification of Acinetobacter baumannii of Human and Animal Origins by a Gene-Specific PCR.

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Hamouda, Ahmed

2017-09-01

Acinetobacter baumannii is a notorious nosocomial pathogen known for its ability to cause severe infections, especially in intensive care units. The identification of a conserved gene encoding a hypothetical protein in A. baumannii isolates but not in other Acinetobacter species during a comparative genomic analysis was reported. For the purpose of this study, we call this gene, A.b_hyp gene. The aim of this study was to report the results of screening for the presence of the A.b_hyp gene in a worldwide collection of well-characterized A. baumannii collected from clinical and animal specimens. A total of 83 clinical, animal, and type strains were used. These comprised 73 A. baumannii isolates of clinical (n = 60) and animal origin (n = 13), and ten type strains, including a positive control strain, A. baumannii ATCC 19606. All isolates were examined by PCR amplification of the A.b_hyp gene. The A.b_hyp gene was detected in 72 isolates (99%) of A. baumannii but one clinical isolate failed to produce an amplicon. The control strain, A. baumannii ATCC 19606, was also positive for this gene. No bands were detected in non-A. baumannii species and therefore the isolates are thought to be negative for the gene. No bands were detected in non-A. baumannii isolates and therefore they are thought to be negative for the gene. The PCR A.b_ hyp method provides evidence that detection of this gene can be used as a reliable, easy, and low-cost biomarker for A. baumannii identification.

Acinetobacter spp. as nosocomial pathogens: Epidemiology and resistance features

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Saad B. Almasaudi

2018-03-01

Full Text Available The genus Acinetobacter is a major cause of nosocomial infections; it is increasingly being associated with various epidemics and has become a widespread concern in a variety of hospitals worldwide. Multi-antibiotic resistant Acinetobacter baumannii, is now recognized to be of great clinical significance. Numerous reports relay to the spread of A. baumannii in the hospital settings which leads to enhanced nosocomial outbreaks associated with high death rates. However, many other Acinetobacter spp. also can cause nosocomial infections. This review focused on the role of Acinetobacter spp. as nosocomial pathogens in addition to their persistence, antimicrobial resistance patterns and epidemiology. Keywords: Acinetobacter, Nosocomial infections, Multi-drug resistance, Epidemiology, Characteristics

Cadmium tolerant characteristic of a newly isolated Lactococcus lactis subsp. lactis.

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Sheng, Yao; Wang, Ying; Yang, Xuan; Zhang, Boyang; He, Xiaoyun; Xu, Wentao; Huang, Kunlun

2016-12-01

Environmental contamination caused by heavy metals poses a major threat to the wildlife and human health for their toxicity and intrinsically persistent nature. Some specific food grade bacteria have properties that enable them to eliminate heavy metals from food and water. Lactococcus lactis subsp. lactis, newly isolated from pickles, is a cadmium (Cd) tolerant bacteria. Cd resistant properties of the lactis was evaluated under different Cd stresses. Cd accumulation in different cellular parts was determined by ICP-MS and cell morphology changes were measured by SEM-EDS and TEM-EDS. In addition, functional groups associated with Cd resistance were detected by infrared spectroscopic analysis. The results indicated that Cd mainly accumulated in the cell surface structures including cytoderm and cytomembrane. Functional groups such as OH and NH 2 in the cell surface played essential roles in Cd biosorption. The elements of O, P, S, and N of polysaccharide, membrane protein and phosphatidate in the cell surface structures might be responsible for Cd biosorption for their strong electronegativity. This study indicated that ultrastructural analysis can be a supplemental method to study heavy metal resistance mechanism of microorganism and the newly isolated lactococcus lactis subsp. lactis has great potential to be applied to decontamination of heavy metals. Copyright © 2016 Elsevier B.V. All rights reserved.

Antibacterial Activity of Pinus pinaster Bark Extract and its Components Against Multidrug-resistant Clinical Isolates of Acinetobacter baumannii

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Mirna Ćurković-Perica

2015-07-01

Full Text Available The aim of this research was to test the antibacterial activity of Pinus pinaster aqueous bark extract (PABE and its basic components against multidrug-resistant isolates of Acinetobacter baumannii belonging to European clone I and II, isolated previously from the clinical outbreaks. The minimum bactericidal concentration of PABE against both clones of A. baumannii was 200 mg ml–1, while lower concentrations showed high antibacterial activity. After 24 h of treatment with 100, 50 or 10 mg ml–1 of extract, the reduction in the number of A. baumannii isolates belonging to European clone I and II was 85.8 ± 2.5 %, 78.5 ± 1.1 %, 66.3 ± 2.5 % and 90.2 ± 1.7 %, 78.6 ± 1.2 %, 69.8 ± 0.7 %, respectively. Several basic components: caffeic acid, catechin, epicatechin, gallic acid and vanillin, detected in the extract by high performance liquid chromatography, contributed to the antibacterial activity of the extract against both clones of A. baumannii. However, the antibacterial activity of extract was higher than that of each tested basic component suggesting that proanthocyanidins, which were present in quite a large amount in the extract, might have also contributed to the activity of the extract. Antibacterial activity of PABE against A. baumannii reveals that complex and inexpensive natural product might be useful in combat against naturally competent bacteria that easily acquire resistance against antibiotics.

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

International Nuclear Information System (INIS)

Christensen, E.A.; Gerner-Smidt, P.; Kristensen, H.

1991-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1991-06-01

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

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 bla OXA-23-like and bla OXA-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 bla OXA-51-like , bla OXA-23-like , bla OXA-24-like , and bla OXA-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 bla OXA-51-like genes. One hundred one out of 110 (92%) imipenem (IMP)-resistant A. baumannii-calcoaceticus complex isolates additionally carried the bla OXA-23-like gene and four isolates (3%) were positive for bla OXA-24-like. All 101 bla OXA-23-like -positive isolates had the ISAba1 insertion sequence, 1,600 bp upstream of the bla OXA-23-like gene. The bla OXA-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

Colonization of long term care facility patients with MDR-Gram-negatives during an Acinetobacter baumannii outbreak

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Ines Zollner-Schwetz

2017-05-01

Full Text Available Abstract Background We aimed to determine the prevalence of colonization by multidrug-resistant Gram-negative bacteria including ESBL-producing enterobacteriaceae, carbapenem-resistant enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii at two wards caring long term for patients with disorder of consciousness at the Geriatric Health Centers Graz, Austria. During our study we detected two A. baumannii outbreaks. Methods In August 2015, we conducted a point-prevalence study. Inguinal and perianal swabs were taken from 38 patients and screened for multidrug-resistant Gram-negative rods using standard procedures. Six months after the initial investigation all patients were sampled again and use of antibiotics during the past 6 months and mortality was registered. Genetic relatedness of bacteria was evaluated by DiversiLab system. Results Fifty percent of patients were colonized by multidrug-resistant Gram-negative isolates. Five patients harboured ESBL-producing enterobacteriaceae. No carbapenem-resistant enterobacteriaceae were detected. 13/38 patients were colonized by A. baumannii isolates (resistant to ciprofloxacin but susceptible to carbapenems. There was a significant difference in the prevalence of colonization by A. baumannii between ward 2 and ward 1 (60% vs. 5.6%, p < 0.001. Two clusters of A. baumannii isolates were identified including one isolate detected on a chair in a patient’s room. Conclusions We detected a high prevalence of two multidrug-resistant A. baumannii strains in patients with disorder of consciousness at a LTCF in Graz, Austria. Our findings strongly suggest nosocomial cross-transmission between patients. An active surveillance strategy is warranted to avoid missing newly emerging pathogens.

Colonization of long term care facility patients with MDR-Gram-negatives during an Acinetobacter baumannii outbreak.

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Zollner-Schwetz, Ines; Zechner, Elisabeth; Ullrich, Elisabeth; Luxner, Josefa; Pux, Christian; Pichler, Gerald; Schippinger, Walter; Krause, Robert; Leitner, Eva

2017-01-01

We aimed to determine the prevalence of colonization by multidrug-resistant Gram-negative bacteria including ESBL-producing enterobacteriaceae, carbapenem-resistant enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii at two wards caring long term for patients with disorder of consciousness at the Geriatric Health Centers Graz, Austria. During our study we detected two A. baumannii outbreaks. In August 2015, we conducted a point-prevalence study. Inguinal and perianal swabs were taken from 38 patients and screened for multidrug-resistant Gram-negative rods using standard procedures. Six months after the initial investigation all patients were sampled again and use of antibiotics during the past 6 months and mortality was registered. Genetic relatedness of bacteria was evaluated by DiversiLab system. Fifty percent of patients were colonized by multidrug-resistant Gram-negative isolates. Five patients harboured ESBL-producing enterobacteriaceae. No carbapenem-resistant enterobacteriaceae were detected. 13/38 patients were colonized by A. baumannii isolates (resistant to ciprofloxacin but susceptible to carbapenems). There was a significant difference in the prevalence of colonization by A. baumannii between ward 2 and ward 1 (60% vs. 5.6%, p  < 0.001). Two clusters of A. baumannii isolates were identified including one isolate detected on a chair in a patient's room. We detected a high prevalence of two multidrug-resistant A. baumannii strains in patients with disorder of consciousness at a LTCF in Graz, Austria. Our findings strongly suggest nosocomial cross-transmission between patients. An active surveillance strategy is warranted to avoid missing newly emerging pathogens.

Molecular Characterization and Antibiotic Susceptibility Pattern of Acinetobacter Baumannii Isolated in Intensive Care Unit Patients in Al-Hassa, Kingdom of Saudi Arabia.

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Alhaddad, Mohammed Sami; AlBarjas, Afnan Khalifah; Alhammar, Lolowah Ebraheem; Al Rashed, Abdullatif Sami; Badger-Emeka, Lorina Ineta

2018-01-01

Acinetobacter baumannii , is an emerging nosocomial multidrug resistance pathogen with the rapid spread of clones being reported in health-care settings and hospitals worldwide. Carbapenem resistance in this bacterium has been attributed to D OXA β-lactamases with OXA-51-like β-lactamase, being present in all A. baumannii isolate. The present study looks into the antibiotics susceptibility and molecular characterization of clinical A. baumannii isolates from Intensive Care Unit (ICU) samples in Al-Hofuf, South-eastern region of Saudi Arabia. Eleven strains of ICU A. baumanni i isolates were used for the investigation. Bacteria isolation was by basic microbiological techniques. Organisms identification and antibiogram susceptibility testing was by the BioMerieux VITEK 2 compact automated system (BioMerieux, Marcy I'Etoile France), according to the manufacturers guidelines. Confirmation of A. baumannii was by the presence of the OX-51 gene, also, carbapenemase encoding resistant genesbla OXA-23 , bla OXA-40 , and bla OXA-51 , were analyzed using multiplex PCR. The Student's t test was used to analyze the obtained data for between group comparisons with statistically significance level set at P < 0.05. Eight of the isolates were confirmed to be A. baumannii . Five of which were resistant to the carbapenems against which they had been tested. One isolate was resistant to tigecycline, whereas three tested intermediate to the drug. OXA-23 was detected in isolates 1, 4, 5, 6, and 7. It can, therefore, be concluded that the probable predominate carbapenems resistant genes in ICU isolates from the present investigation, are those associated with OXA-23.

Comparative Analysis of 37 Acinetobacter Bacteriophages

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Dann Turner

2017-12-01

Full Text Available Members of the genus Acinetobacter are ubiquitous in the environment and the multiple-drug resistant species A. baumannii is of significant clinical concern. This clinical relevance is currently driving research on bacterial viruses infecting A. baumannii, in an effort to implement phage therapy and phage-derived antimicrobials. Initially, a total of 42 Acinetobacter phage genome sequences were available in the international nucleotide sequence databases, corresponding to a total of 2.87 Mbp of sequence information and representing all three families of the order Caudovirales and a single member of the Leviviridae. A comparative bioinformatics analysis of 37 Acinetobacter phages revealed that they form six discrete clusters and two singletons based on genomic organisation and nucleotide sequence identity. The assignment of these phages to clusters was further supported by proteomic relationships established using OrthoMCL. The 4067 proteins encoded by the 37 phage genomes formed 737 groups and 974 orphans. Notably, over half of the proteins encoded by the Acinetobacter phages are of unknown function. The comparative analysis and clustering presented enables an updated taxonomic framing of these clades.

Integron types, gene cassettes and antimicrobial resistance profile of Acinetobacter baumannii isolated from BAL samples in Babol, north of Iran.

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Akrami, Fariba; Shahandashti, Elaheh Ferdosi; Yahyapour, Yousef; Sadeghi, Mohsen; Khafri, Soraya; Pournajaf, Abazar; Rajabnia, Ramazan

2017-08-01

Multi-drug resistant isolates of Acinetobacter baumannii have created therapeutic problems worldwide. This current study was intended to determine the Integron types, gene cassettes and antimicrobial resistance profile of A. baumannii isolated from BAL samples in Babol, north of Iran. During a 15-month period, 35 A. baumannii isolates were studied. Different classes of antimicrobial agents were used to determine the resistance ratios. Multiplex-PCR was used to detect different types of integrons and associated gene cassettes. The resistance rates to GM, FEP, AK, TOB, CP, PIP, SAM, IPM, SXT, CTX, CAZ, CL, TIM, MEM, and TZP were 85.7%, 100%, 91.4%, 68.5%, 94.3%, 88.5%, 97.1%, 94.3%, 100%, 100%, 100%, 0.0%, 91.4%, 94.3% and 91.4%, respectively. The distribution analysis of int genes showed that 25.7%, 88.6% and 28.6% of isolates carried the intI, intII and intIII genes, respectively. The prevalence of aadB, dfrA1, bla-OXA 30 and aadA1 genes were 94.3%, 77.1%, 40% and 5.7%, respectively. The current study showed that a high level of A. baumannii isolates harbor integrons in our therapeutic center, which may lead to distribution of multiple antimicrobial resistance. The different types of gene cassette arrays in the present study highlight the important role of geographical features in MDR isolates dissemination which could be credited to different profiles of drug consumption in different areas. The findings emphasized that the need for continuous surveillance to prevent distribution of multidrug resistance among A. baumannii strains in Iran. Copyright © 2017. Published by Elsevier Ltd.

Immune Regulatory Effect of Newly Isolated Lactobacillus delbrueckii from Indian Traditional Yogurt.

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Hong, Yi-Fan; Lee, Yoon-Doo; Park, Jae-Yeon; Jeon, Boram; Jagdish, Deepa; Jang, Soojin; Chung, Dae Kyun; Kim, Hangeun

2015-08-01

Lactic acid bacteria (LAB) are microorganisms that are believed to provide health benefits. Here, we isolated LAB from Indian fermented foods, such as traditional Yogurt and Dosa. LAB from Yogurt most significantly induced TNF-α and IL-1β production, whereas LAB from Dosa induced mild cytokine production. After 16S rRNA gene sequencing and phylogenetic analysis, a Yogurt-borne lactic acid bacterium was identified and classified as Lactobacillus delbrueckii subsp. bulgaricus, and it was renamed L. delbrueckii K552 for the further studies. Our data suggest that the newly isolated L. delbrueckii can be used for the treatment of immune deficiency disorders.

Prevalence and risk factors of metallo β-lactamase producing Pseudomonas aeruginosa and Acinetobacter species in burns and surgical wards in a tertiary care hospital

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Simit H Kumar

2012-01-01

Full Text Available Introduction: The production of Metallo-β-lactamases (MBLs is one of the resistance mechanisms of Pseudomonas aeruginosa and Acinetobacter species. There is not much Indian data on the prevalence of MBLs in burns and surgical wards. Materials and Methods: A total of 145 non-duplicate isolates of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter species, isolated from pus/wound swabs and endotracheal secretions from burns and surgical wards, were tested for MBL production by modified ethylene diamine tetra acetic acid (EDTA disc synergy and double disc synergy tests. Results: Prevalence of MBLs was 26.9% by both the above tests. All MBL-positive isolates were multidrug resistant. Only 6.06% (2/33 P.aeruginosa and 16.67% (1/06 Acinetobacter species were susceptible to piperacillin-tazobactam and netilmycin, respectively. These patients had multiple risk factors like >8 days hospital stay, catheterization, IV lines, previous antibiotic use, mechanical ventilation, etc. Graft application and surgical intervention were significant risk factors in MBL-positive patients. Overall mortality in MBL-positive patients was 34.21%. Conclusion: Emergence of MBL-producing Pseudomonas aeruginosa and Acinetobacter species in this hospital is alarming, which reflect excessive use of carbapenems and at the same time, pose a therapeutic challenge to clinicians as well as to microbiologists. Therefore, a strict antibiotic policy and implementation of proper infection control practices will go a long way to prevent further spread of MBLs. Detection of MBLs should also become mandatory in all hospitals.

Bioorthogonal Chemistry for the Isolation and Study of Newly Synthesized Histones and Their Modifications.

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Arnaudo, Anna M; Link, A James; Garcia, Benjamin A

2016-03-18

The nucleosome is an octamer containing DNA wrapped around one histone H3-H4 tetramer and two histone H2A-H2B dimers. Within the nucleosome, histones are decorated with post-translational modifications. Previous studies indicate that the H3-H4 tetramer is conserved during DNA replication, suggesting that old tetramers serve as a template for the modification of newly synthesized tetramers. Here, we present a method that merges bioorthogonal chemistry with mass spectrometry for the study of modifications on newly synthesized histones in mammalian cells. HeLa S3 cells are dually labeled with the methionine analog azidohomoalanine and heavy (13)C6,(15)N4 isotope labeled arginine. Heavy amino acid labeling marks newly synthesized histones while azidohomoalanine incorporation allows for their isolation using bioorthogonal ligation. Labeled mononucleosomes were covalently linked via a copper catalyzed reaction to a FLAG-GGR-alkyne peptide, immunoprecipitated, and subjected to mass spectrometry for quantitative modification analysis. Mononucleosomes containing new histones were successfully isolated using this approach. Additionally, the development of this method highlights the potential deleterious effects of azidohomoalanine labeling on protein PTMs and cell cycle progression, which should be considered for future studies utilizing bioorthogonal labeling strategies in mammalian cells.

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

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Emad Mohamed Abdallah

2016-11-01

Full Text Available Objective: To evaluate the antibacterial activity of methanol extract of Hibiscus sabdariffa (H. sabdariffa calyces employed in Sudanese folk medicine against five hospital isolates of multidrug resistant Acinetobacter baumannii (MDR A. baumannii. Methods: The antibacterial activity of 80% methanol extract (v/v of H. sabdariffa calyces was evaluated by agar disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration methods. Antibiotic susceptibility of selected A. baumannii strains was tested. Results: In the present investigation, the methanol extract from the calyces of H. sabdariffa exhibited significant antibacterial properties against the non-MDR A. baumannii as well as the MDR A. baumannii strains with a zone of inhibition ranging from (11.3 ± 0.3 to (13.6 ± 0.3 mm. The relative percentage inhibition of H. sabdariffa extract (10 mg/disc with respect to gentamicin (10 mg/disc had potent antibacterial properties and was much more effective than gentamicin. Values of minimum inhibitory concentration and minimum bactericidal concentration ranged from 25 to 50 and 50 to 100 mg/mL, respectively, revealing the potential bactericidal properties of the extract. Conclusions: According to the present study, the calyces of H. sabdariffa can be used as a substitute source of the current ineffective synthetic antibiotics used against MDR A. baumannii.

Resistência a β-lactâmicos em Acinetobacter spp isolados de efluente hospitalar no sul do Brasil Resistance to β-lactams among Acinetobacter spp isolated from hospital sewage in southern Brazil

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Carolina de Souza Gusatti

2009-04-01

Full Text Available Acinetobacter spp é um importante patógeno causador de infecções nosocomiais que acomete pacientes imunocomprometidos e capaz de adquirir resistência a antimicrobianos com facilidade. Os esgotos hospitalares são importantes disseminadores de genes de resistência a antimicrobianos para a microbiota ambiental. Neste contexto, 30 cepas de Acinetobacter spp provenientes de efluente de um hospital em Porto Alegre, RS, foram analisados quanto ao perfil de susceptibilidade a β-lactamases, quinolonas e aminoglicosídeos através de antibiograma e testes de triagem para metalo beta-lactamases e β-lactamases de espectro estendido. O perfil encontrado revela cepas multi-resistentes e que mecanismos de resistência como a produção de β-lactamases de espectro estendido e bombas de efluxo podem estar presentes nesses isolados.Acinetobacter spp is an important pathogen that is responsible for nosocomial infections affecting immunocompromised patients, and it can easily acquire resistance to antimicrobial agents. Hospital sewage is an important means for disseminating genes for resistance to antimicrobial agents, to the microbiota of the environment. Within this context, 30 strains of Acinetobacter spp from the sewage of a hospital in Porto Alegre, Rio Grande do Sul, were analyzed regarding their profile of susceptibility to β-lactams, quinolones and aminoglycosides, by means of an antibiogram and tests to screen for metallo-β-lactamases and extended-spectrum β-lactamases. The profile obtained revealed the presence of multidrug-resistant strains and showed that resistance mechanisms such as the production of extended-spectrum β-lactamases and efflux pumps may be present in these strains.

Reduction in chlorhexidine efficacy against multi-drug-resistant Acinetobacter baumannii international clone II.

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Hayashi, M; Kawamura, K; Matsui, M; Suzuki, M; Suzuki, S; Shibayama, K; Arakawa, Y

2017-03-01

Nosocomial infections caused by Acinetobacter baumannii international clone II (IC II) can cause severe clinical outcomes. Differential evaluation of bactericidal efficacy of chlorhexidine gluconate (CHX) and benzethonium chloride (BZT) disinfectants against IC II and non-IC II isolates. Minimum inhibitory concentrations (MICs) of CHX and BZT were determined for 137 A. baumannii IC II, 99 non-IC II and 69 non-baumannii isolates, further classified according to MIC values into disinfectant-reduced susceptible (DRS) and disinfectant-susceptible (DS) groups. Time-kill curves and minimum bactericidal concentrations (MBCs) were evaluated for representative isolates in each group. CHX and BZT MIC 90 s for IC II isolates were 100 and 175mg/L, respectively, but those for non-IC II and non-baumannii isolates were <100mg/L. Nevertheless, time-kill curves indicated that CHX and BZT reduced live bacterial cell number by 5 log 10 for IC II and non-IC II isolates within 30s when used at 1000mg/L, comparable to practical use concentrations. CHX MBC at 30s was 1000mg/L for IC II and non-IC II isolates, and was not influenced by addition of 3% bovine serum albumin (BSA); BZT MBC at 30s was 100mg/L without BSA and increased up to 500mg/L upon addition of BSA. No significant differences in BSA were found between DRS and DS isolates. CHX and BZT were effective against Acinetobacter spp. including IC II at a concentration of 1000mg/L and exposure for at least 30s, but their concentrations should be considered carefully to ensure sufficient effects in both clinical and healthcare settings. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

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

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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.

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

Nanoparticles for Control of Biofilms of Acinetobacter Species

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Richa Singh

2016-05-01

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

Epidemic Dissemination of a Carbapenem-Resistant Acinetobacter baumannii Clone Carrying armA Two Years After Its First Isolation in an Italian Hospital.

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Milan, Annalisa; Furlanis, Linda; Cian, Franca; Bressan, Raffaela; Luzzati, Roberto; Lagatolla, Cristina; Deiana, Maria Luisa; Knezevich, Anna; Tonin, Enrico; Dolzani, Lucilla

2016-12-01

This study describes the dissemination of a carbapenem-resistant Acinetobacter baumannii (CRAB) strain in a university hospital in Northeast Italy. Characterization of the outbreak strain was combined with a retrospective analysis of all CRAB isolates collected in the same hospital during the 5 years preceding the outbreak, with the aim of elucidating the origin of the epidemic spread. The outbreak strain was shown to belong to the International Clone II and carry the bla OXA-23 gene, flanked by two ISAba1 sequences in opposite orientation (Tn2006 arrangement). The epidemic clone harbored also the bla OXA-66 allele of the carbapenemase intrinsic to A. baumannii, the determinant of ArmA 16S rRNA methylase and a class 1 integron, with the aacA4, catB8, and aadA1 cassette array. Genotype analysis, performed by macrorestriction analysis and VRBA, revealed that isolates related to outbreak strain had been sporadically collected from inpatients in the 2 years preceding outbreak start. Carriage of bla OXA-66 , armA, and the integron further supported relatedness of these isolates to the outbreak clone. Outbreak initially involved three medical wards, typically hosting elderly patients with a history of prolonged hospitalization. The study highlights the need to adopt strict infection control measures also when CRAB isolation appears to be a sporadic event.

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

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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.

Insertions in the OCL1 locus of Acinetobacter baumannii lead to shortened lipooligosaccharides

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Kenyon, Johanna J.; Holt, Kathryn E.; Pickard, Derek; Dougan, Gordon; Hall, Ruth M.

2014-01-01

Genomes of 82 Acinetobacter baumannii global clones 1 (GC1) and 2 (GC2) isolates were sequenced and different forms of the locus predicted to direct synthesis of the outer core (OC) of the lipooligosaccharide were identified. OCL1 was in all GC2 genomes, whereas GC1 isolates carried OCL1, OCL3 or a new locus, OCL5. Three mutants in which an insertion sequence (ISAba1 or ISAba23) interrupted OCL1 were identified. Isolates with OCL1 intact produced only lipooligosaccharide, while the mutants produced lipooligosaccharide of reduced molecular weight. Thus, the assignment of the OC locus as that responsible for the synthesis of the OC is correct. PMID:24861001

Informing Antibiotic Treatment Decisions: Evaluating Rapid Molecular Diagnostics To Identify Susceptibility and Resistance to Carbapenems against Acinetobacter spp. in PRIMERS III.

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Evans, Scott R; Hujer, Andrea M; Jiang, Hongyu; Hill, Carol B; Hujer, Kristine M; Mediavilla, Jose R; Manca, Claudia; Tran, Thuy Tien T; Domitrovic, T Nicholas; Higgins, Paul G; Seifert, Harald; Kreiswirth, Barry N; Patel, Robin; Jacobs, Michael R; Chen, Liang; Sampath, Rangarajan; Hall, Thomas; Marzan, Christine; Fowler, Vance G; Chambers, Henry F; Bonomo, Robert A

2017-01-01

The widespread dissemination of carbapenem-resistant Acinetobacter spp. has created significant therapeutic challenges. At present, rapid molecular diagnostics (RMDs) that can identify this phenotype are not commercially available. Two RMD platforms, PCR combined with electrospray ionization mass spectrometry (PCR/ESI-MS) and molecular beacons (MB), for detecting genes conferring resistance/susceptibility to carbapenems in Acinetobacter spp. were evaluated. An archived collection of 200 clinical Acinetobacter sp. isolates was tested. Predictive values for susceptibility and resistance were estimated as a function of susceptibility prevalence and were based on the absence or presence of beta-lactamase (bla) NDM, VIM, IMP, KPC, and OXA carbapenemase genes (e.g., bla OXA-23 , bla OXA-24/40 , and bla OXA-58 found in this study) against the reference standard of MIC determinations. According to the interpretation of MICs, 49% (n = 98) of the isolates were carbapenem resistant (as defined by either resistance or intermediate resistance to imipenem). The susceptibility sensitivities (95% confidence interval [CI]) for imipenem were 82% (74%, 89%) and 92% (85%, 97%) for PCR/ESI-MS and MB, respectively. Resistance sensitivities (95% CI) for imipenem were 95% (88%, 98%) and 88% (80%, 94%) for PCR/ESI-MS and MB, respectively. PRIMERS III establishes that RMDs can discriminate between carbapenem resistance and susceptibility in Acinetobacter spp. In the context of a known prevalence of resistance, SPVs and RPVs can inform clinicians regarding the best choice for empiric antimicrobial therapy against this multidrug-resistant pathogen. Copyright © 2016 American Society for Microbiology.

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

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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.

Pneumonia caused by extensive drug-resistant Acinetobacter baumannii among hospitalized patients: genetic relationships, risk factors and mortality.

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Li, Yu Jun; Pan, Chu Zhi; Fang, Chang Quan; Zhao, Zhu Xiang; Chen, Hui Ling; Guo, Peng Hao; Zhao, Zi Wen

2017-05-30

The clonal spread of multiple drug-resistant Acinetobacter baumannii is an emerging problem in China. We analysed the molecular epidemiology of Acinetobacter baumanni isolates at three teaching hospitals and investigated the risk factors, clinical features, and outcomes of hospital-acquired pneumonia caused by extensive drug-resistant Acinetobacter baumannii (XDRAB) infection in Guangzhou, China. Fifty-two A. baumannii isolates were collected. Multilocus sequence typing (MLST) was used to assess the genetic relationships among the isolates. The bla OXA-51-like gene was amplified using polymerase chain reaction (PCR) and sequencing. The resistance phenotypes were determined using the disc diffusion method. A retrospective case-control study was performed to determine factors associated with XDRAB pneumonia. Most of the 52 A. baumannii isolates (N = 37, 71.2%) were collected from intensive care units (ICUs). The respiratory system was the most common bodily site from which A. baumannii was recovered (N = 45, 86.5%). Disc diffusion classified the isolates into 17 multidrug-resistant (MDR) and 35 extensively drug-resistant (XDR) strains. MLST grouped the A. baumannii isolates into 5 existing sequence types (STs) and 7 new STs. ST195 and ST208 accounted for 69.2% (36/52) of the isolates. The clonal relationship analysis showed that ST195 and ST208 belonged to clonal complex (CC) 92. According to the sequence-based typing (SBT) of the bla OXA-51-like gene, 51 A. baumannii isolates carried OXA-66 and the rest carried OXA-199. There were no significant differences with respect to the resistance phenotype between the CC92 and non-CC92 strains (P = 0.767). The multivariate analysis showed that the APACHE II score, chronic obstructive pulmonary disease (COPD) and cardiac disease were independent risk factors for XDRAB pneumonia (P < 0.05). The mortality rate of XDRAB pneumonia was high (up to 42.8%), but pneumonia caused by XDRAB was not associated with in

CARBAPENEM-RESISTANT ACINETOBACTER BAUMANII POSTOPERATIVE MENINGITIS

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Laura Ghibu; Egidia Miftode; Olivia Dorneanu; Carmen Dorobat

2011-01-01

Acinetobacter baumannii is an opportunistic pathogen of increasing relevance in hospital infections during the last 15 years.This organism causes a wide range of infection .Extensive use of antibiotics within hospitals has contribute to the emergence of multidrug-resistent A.baumannii strains that exhibit resistance to a wide range of antibiotics ,including carbapenems.We report the case of an 37 years old man diagnosed with Acinetobacter multidrug-resistant post-neurosurgical meningitis with...

Mortalidad por Acinetobacter baumannii en unidades de cuidados intensivos en Colombia Acinetobacter baumannii - related mortality in intensive care units in Colombia

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Elkin V Lemos

2011-10-01

Full Text Available OBJETIVO: Comparar la mortalidad en pacientes infectados por Acinetobacter baumannii multisensibles con pacientes infectados por A. baumannii multirresistentes hospitalizados en unidades de cuidados intensivos (UCI de Colombia. MÉTODOS: Estudio prospectivo, observacional y multicéntrico. Se incluyó a 165 pacientes ingresados en las UCIs participantes entre abril de 2006 y abril de 2010. Se comparó la mortalidad de los pacientes con aislamientos clínicos de A. baumannii multirresistentes frente a aquellos multisensibles al día 14 y 30 de hospitalización. RESULTADOS: De los 165 pacientes adultos que presentaron infecciones asociadas al cuidado en salud (IACS por A. baumannii, en 62 se encontraron bacterias multisensibles y en 103, multirresistentes. No se hallaron diferencias estadísticamente significativas en la mortalidad al día 14 de hospitalización en UCI. Sí se observaron en cambio diferencias significativas (P OBJECTIVE: Compare mortality in multidrug-susceptible Acinetobacter baumannii infected patients and multidrug-resistant A. baumannii-infected patients hospitalized in intensive care units (ICUs in Colombia. METHODS: A prospective, observational, and multicenter study. A total of 165 patients admitted to the participating ICUs from April 2006 to April 2010 were included. On day 14 and day 30 of hospitalization, mortality in multidrug-resistant patients with clinical isolates of A. baumannii was compared with that in multidrug-susceptible patients. RESULTS: Of the 165 adult patients who had health care-associated infections (HAI caused by A. baumannii, multidrug-susceptible bacteria were found in 62 patients and multidrug-resistant bacteria in 103. Statistically significant differences in mortality on day 14 of hospitalization in the ICU were not found. On the other hand, significant differences (P < 0.05 in mortality on day 30 of hospitalization were observed between patients with multidrug-resistant isolates and those with

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

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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.

Characterization of Acinetobacter baumannii clinical isolates carrying bla(OXA-23) carbapenemase and 16S rRNA methylase armA genes in Yemen.

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Bakour, Sofiane; Alsharapy, Samer Ahmed; Touati, Abdelaziz; Rolain, Jean-Marc

2014-12-01

The aim of this study was to investigate the molecular support of resistance to carbapenems, aminoglycosides, and fluoroquinolones in Acinetobacter baumannii clinical isolates collected from Yemen hospital. Three A. baumannii were isolated in February 2013 from three patients hospitalized at Al-Thawra University Hospital in Sana'a, Yemen. Antibiotic susceptibility testing was performed using the disk diffusion and E-test methods. Carbapenemase production was carried out by the modified Hodge test (MHT) and imipenem-ethylenediaminetetraacetic acid (EDTA) methods. Carbapenem, aminoglycoside, and fluoroquinolone resistance determinants were studied by polymerase chain reaction and sequencing. The epidemiological relatedness of the three strains was studied using multilocus sequence typing (MLST). The isolates were resistant to almost all antibiotics tested with very high imipenem, amikacin, and ciprofloxacin minimum inhibitory concentrations (>32, >256, and >32 mg/L, respectively). The microbiological tests showed that the three A. baumannii were MHT positive, besides, the activity of β-lactamases was not inhibited by EDTA. All the three isolates contained the naturally occurring bla(OXA-51)-like gene and the bla(OXA-23)-like carbapenemase-encoding gene. The 16S rRNA methylase armA gene was detected in the three isolates. In addition, screening for genes encoding the aminoglycoside-modifying enzymes (AMEs) demonstrated that one isolate contained the acetyltransferase gene aac(6')-Ib. Fluoroquinolone resistance was associated with a single mutation Ser83Leu in the quinolone resistance determining region of the gyrA gene in all isolates. The MLST showed that the sequence type (ST) obtained corresponds to ST2 for the three strains. Here we report the first identification of multidrug-resistant A. baumannii isolates harboring the bla(OXA-23)-like gene, AMEs [aac(6')-Ib], and the 16S rRNA methylase (armA) in the Yemen hospital.

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

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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.

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

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Bilocq, Florence; Jennes, Serge; Verbeken, Gilbert; Rose, Thomas; Keersebilck, Elkana; Bosmans, Petra; Pieters, Thierry; Hing, Mony; Heuninckx, Walter; De Pauw, Frank; Soentjens, Patrick; Merabishvili, Maia; Deschaght, Pieter; Vaneechoutte, Mario; Bogaerts, Pierre; Glupczynski, Youri; Pot, Bruno; van der Reijden, Tanny J.; Dijkshoorn, Lenie

2016-01-01

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. PMID:27223476

Time dependent enhanced resistance against antibiotics & metal salts by planktonic & biofilm form of Acinetobacter haemolyticus MMC 8 clinical isolate

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Sharvari Vijaykumar Gaidhani

2014-01-01

Full Text Available Background & objectives: Available literature shows paucity of reports describing antibiotic and metal resistance profile of biofilm forming clinical isolates of Acinetobacter haemolyticus. The present study was undertaken to evaluate the antibiotic and metal resistance profile of Indian clinical isolate of A. haemolyticus MMC 8 isolated from human pus sample in planktonic and biofilm form. Methods: Antibiotic susceptibility and minimum inhibitory concentration were determined employing broth and agar dilution techniques. Biofilm formation was evaluated quantitatively by microtiter plate method and variation in complex architecture was determined by scanning electron microscopy. Minimum biofilm inhibiting concentration was checked by Calgary biofilm device. Results: Planktonic A. haemolyticus MMC 8 was sensitive to 14 antibiotics, AgNO 3 and HgC1 2 resistant to streptomycin and intermediately resistant to netilmycin and kanamycin. MMC 8 exhibited temporal variation in amount and structure of biofilm. There was 32 - 4000 and 4 - 256 fold increase in antibiotic and metal salt concentration, respectively to inhibit biofilm over a period of 72 h as against susceptible planktonic counterparts. Total viable count in the range of 10 5 -10 6 cfu / ml was observed on plating minimum biofilm inhibiting concentration on Muller-Hinton Agar plate without antimicrobial agents. Biofilm forming cells were several folds more resistant to antibiotics and metal salts in comparison to planktonic cells. Presence of unaffected residual cell population indicated presence of persister cells. Interpretation & conclusions: The results indicate that biofilm formation causes enhanced resistance against antibiotics and metal salts in otherwise susceptible planktonic A. haemolyticus MMC 8.

Molecular characterization and antimicrobial susceptibility of Acinetobacter baumannii isolates obtained from two hospital outbreaks in Los Angeles County, California, USA.

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Warner, Wayne A; Kuang, Shan N; Hernandez, Rina; Chong, Melissa C; Ewing, Peter J; Fleischer, Jen; Meng, Jia; Chu, Sheena; Terashita, Dawn; English, L'Tanya; Chen, Wangxue; Xu, H Howard

2016-05-04

Antibiotic resistant strains of Acinetobacter baumannii have been responsible for an increasing number of nosocomial infections including bacteremia and ventilator-associated pneumonia. In this study, we analyzed 38 isolates of A. baumannii obtained from two hospital outbreaks in Los Angeles County for the molecular epidemiology, antimicrobial susceptibility and resistance determinants. Pulsed field gel electrophoresis, tri-locus multiplex PCR and multi-locus sequence typing (Pasteur scheme) were used to examine clonal relationships of the outbreak isolates. Broth microdilution method was used to determine antimicrobial susceptibility of these isolates. PCR and subsequent DNA sequencing were employed to characterize antibiotic resistance genetic determinants. Trilocus multiplex PCR showed these isolates belong to Global Clones I and II, which were confirmed to ST1 and ST2, respectively, by multi-locus sequence typing. Pulsed field gel electrophoresis analysis identified two clonal clusters, one with 20 isolates (Global Clone I) and the other with nine (Global Clone II), which dominated the two outbreaks. Antimicrobial susceptibility testing using 14 antibiotics indicated that all isolates were resistant to antibiotics belonging to four or more categories of antimicrobial agents. In particular, over three fourth of 38 isolates were found to be resistant to both imipenem and meropenem. Additionally, all isolates were found to be resistant to piperacillin, four cephalosporin antibiotics, ciprofloxacin and levofloxacin. Resistance phenotypes of these strains to fluoroquinolones were correlated with point mutations in gyrA and parC genes that render reduced affinity to target proteins. ISAba1 was detected immediately upstream of the bla OXA-23 gene present in those isolates that were found to be resistant to both carbapenems. Class 1 integron-associated resistance gene cassettes appear to contribute to resistance to aminoglycoside antibiotics. The two outbreaks were

Production and properties of biosurfactants from a newly isolated Pseudomonas fluorescens HW-6 growing on hexandecane

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Vasileva-Tonkova, E.; Galabova, D. [Bulgarian Academy of Sciences, Dept. of Microbial Biochemistry, Sofia (Bulgaria); Stoimenova, E.; Lalchev, Z. [Dept. of Biochemistry, Sofia Univ. ' ' St. Kliment Ohridski' ' , Sofia (Bulgaria)

2006-07-15

The newly isolated from industrial wastewater Pseudomonas fluorescens strain HW-6 produced glycolipid biosurfactants at high concentrations (1.4-2.0 g 1{sup -1}) when grown on hexadecane as a sole carbon source. Biosurfactants decreased the surface tension of the air/water interface by 35 mN m{sup -1} and possessed a low critical micelle concentration value of 20 mg 1{sup -1}, which indicated high surface activity. They efficiently emulsified aromatic hydrocarbons, kerosene, n-paraffins and mineral oils. Biosurfactant production contributed to a significant increase in cell hydrophobicity correlated with an increased growth of the strain on hexadecane. The results suggested that the newly isolated strain of Ps. fluorescens and produced glycolipid biosurfactants with effective surface and emulsifying properties are very promising and could find application for bioremediation of hydrocarbon-polluted sites. (orig.)

In vitro activity of colistin in antimicrobial combination against carbapenem-resistant Acinetobacter baumannii isolated from patients with ventilator-associated pneumonia in Vietnam.

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Le Minh, Vien; Thi Khanh Nhu, Nguyen; Vinh Phat, Voong; Thompson, Corinne; Huong Lan, Nguyen Phu; Thieu Nga, Tran Vu; Thanh Tam, Pham Thi; Tuyen, Ha Thanh; Hoang Nhu, Tran Do; Van Hao, Nguyen; Thi Loan, Huynh; Minh Yen, Lam; Parry, Christopher M; Trung Nghia, Ho Dang; Campbell, James I; Hien, Tran Tinh; Thwaites, Louise; Thwaites, Guy; Van Vinh Chau, Nguyen; Baker, Stephen

2015-10-01

Acinetobacter baumannii has become one of the major infection threats in intensive care units (ICUs) globally. Since 2008, A. baumannii has been the leading cause of ventilator-associated pneumonia (VAP) in our ICU at an infectious disease hospital in southern Vietnam. The emergence of this pathogen in our setting is consistent with the persistence of a specific clone exhibiting resistance to carbapenems. Antimicrobial combinations may be a strategy to treat infections caused by these carbapenem-resistant A. baumannii. Therefore, we assessed potential antimicrobial combinations against local carbapenem-resistant A. baumannii by measuring in vitro interactions of colistin with four antimicrobials that are locally certified for treating VAP. We first performed antimicrobial susceptibility testing and multilocus variable number tandem repeat analysis (MLVA) genotyping on 74 A. baumannii isolated from quantitative tracheal aspirates from patients with VAP over an 18-month period. These 74 isolates could be subdivided into 21 main clusters by MLVA and >80 % were resistant to carbapenems. We selected 56 representative isolates for in vitro combination synergy testing. Synergy was observed in four (7 %), seven (13 %), 20 (36 %) and 38 (68 %) isolates with combinations of colistin with ceftazidime, ceftriaxone, imipenem and meropenem, respectively. Notably, more carbapenem-resistant A. baumannii isolates (36/43; 84 %) exhibited synergistic activity with a combination of colistin and meropenem than carbapenem-susceptible A. baumannii isolates (2/13; 15 %) (P = 0.023; Fisher's exact test). Our findings suggest that combinations of colistin and meropenem should be considered when treating carbapenem-resistant A. baumannii infections in Vietnam, and we advocate clinical trials investigating combination therapy for VAP.

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

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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.

5,7-Di-N-acetyl-8-epiacinetaminic acid: A new non-2-ulosonic acid found in the K73 capsule produced by an Acinetobacter baumannii isolate from Singapore.

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Kenyon, Johanna J; Notaro, Anna; Hsu, Li Yang; De Castro, Cristina; Hall, Ruth M

2017-09-12

Nonulosonic acids are found in the surface polysaccharides of many bacterial species and are often implicated in pathogenesis. Here, the structure of a novel 5,7-diacetamido-3,5,7,9-tetradeoxynon-2-ulosonic acid recovered from the capsular polysaccharide of a multiply antibiotic resistant Acinetobacter baumannii isolate was determined. The isolate carries a sugar synthesis module that differs by only a single gene from the module for the synthesis of 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulosonic acid or 5,7-di-N-acetylacinetaminic acid, recently discovered in the capsule of another A. baumannii isolate. The new monosaccharide is the C8-epimer of acinetaminic acid (8eAci; 5,7-diacetamido-3,5,7,9-tetradeoxy-D-glycero-L-altro-non-2-ulosonic acid) and the C7-epimer of legionaminic acid. This monosaccharide had not previously been detected in a biological sample but had been synthesized chemically.

Molecular and epidemiological characterisation of clinical isolates of carbapenem-resistant Acinetobacter baumannii from public and private sector intensive care units in Karachi, Pakistan.

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Irfan, S; Turton, J F; Mehraj, J; Siddiqui, S Z; Haider, S; Zafar, A; Memon, B; Afzal, O; Hasan, R

2011-06-01

The purpose of this study was to identify molecular and epidemiological characteristics of hospital-acquired carbapenem-resistant Acinetobacter baumannii (CRAB) from two different intensive care unit (ICU) settings in Karachi, Pakistan. A cross-sectional study was performed in the adult ICUs of a private sector tertiary care hospital (PS-ICU) and of a government sector hospital (GS-ICU) between November 2007 and August 2008. Deduplicated CRAB isolates from clinical specimens were examined for carbapenemase and class 1 integrase genes. Isolates were typed using sequence-based multiplex polymerase chain reaction, pulsed-field gel electrophoresis (PFGE) and variable number tandem repeat (VNTR). A total of 50 patients (33 from PS-ICU and 17 from GS-ICU) were recruited. There were statistically significant differences between patients in the two ICUs in terms of mean age, comorbidities, the presence of central venous pressure lines, urinary catheters, and average length of stay. bla(OxA-23-like) acquired-oxacillinase genes were found in 47/50 isolates. Class 1 integrase genes were found in 50% (25/50) of the organisms. The majority of isolates belonged to strains of European clones I and II. PFGE typing grouped the isolates into eight distinct clusters, three of which were found in both hospitals. Most of the isolates within each PFGE cluster shared identical or highly similar VNTR profiles, suggesting close epidemiological association. Irrespective of differences in risk factors and infection control policies and practices, the extent of clonality among CRAB isolates was very similar in both ICU settings. Copyright © 2011 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Phenotypic and Genotypic Detection of Metallo-beta-lactamases among Imipenem-Resistant Gram Negative Isolates

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Mohammad Mohammadzadeh

2016-08-01

Full Text Available Background:   Imipenem-resistant gram negative bacteria, resulting from metallo-beta-lactamase (MBLs-producing strains have been reported to be among the important causes of nosocomial infections and of serious therapeutic problem worldwide. Because of their broad range, potent carbapenemase activity and resistance to inhibitors, these enzymes can confer resistance to almost all beta-lactams. The prevalence of metallo-beta-lactamase among imipenem-resistant Acinetobacter spp., Pseudomonas spp. and Enerobacteriaceae isolates is determined.Methods:   In this descriptive study 864 clinical isolates of Acinetobacter spp., Pseudomonas spp. and Enterobacteriaceae, were initially tested for imipenem susceptibility. The metallo-beta-lactamase production was detected using combined disk diffusion, double disk synergy test, and Hodge test. Then all imipenem resistant isolates were tested by PCR for imp, vim and ndm genes. Results:   Among 864 isolates, 62 (7.17 % were imipenem-resistant. Positive phonetypic test for metallo-beta-lactamase was 40 (64.5%, of which 24 (17.1% and 16 (9.2% isolates were Acinetobacter spp. and Pseudomonas spp., respectively. By PCR method 30 (48.4% of imipenem resistant Acinetobacter, and Pseudomonas isolates were positive for MBL-producing genes. None of the Enterobacteriaceae isolates were positive for metallo-beta-lactamase activity. Conclusion:   The results of this study are indicative of the growing number of nosocomial infections associated with multidrug-resistant gram negative bacteria in this region leading to difficulties in antibiotic therapy. Thereby, using of phenotypic methods can be helpful for management of this problem.

[Community-acquired Acinetobacter pneumonia].

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Bernasconi, E; Wüst, J; Speich, R; Flury, G; Krause, M

1993-08-21

We report the history of a 38-year-old male native of Sri Lanka admitted to the emergency ward because of chest pain and shortness of breath. On physical and radiographic examination a bilateral predominantly right-sided pneumonia was found. The patient was admitted to the medical ICU and an antibiotic regimen with amoxicillin/clavulanic acid and erythromycin was initiated. Shortly afterwards septic shock developed. The patient was intubated and received high doses of catecholamines. He died 30 hours after admission to the hospital. Cultures from sputum, tracheal aspirate and blood grew Acinetobacter baumanni. Acinetobacter is an ubiquitous gram-negative rod with coccobacillary appearance in clinical specimens, that may appear gram-positive due to poor discoloration on Gram-stain. It is a well known causative agent of nosocomial infections, particularly in intensive care units. Community-acquired pneumonias, however, are quite rare. Sporadic cases have been reported from the US, Papua-New Guinea and Australia. Interestingly, these pneumonias are fulminant and have a high mortality. Chronic obstructive lung disease, diabetes, and tobacco and alcohol consumption appear to be predisposing factors. Due to the rapid course and poor prognosis, prompt diagnosis and adequate antibiotic treatment are indicated. Antibiotics use for community-acquired pneumonias, such as amoxicillin/clavulanic acid or macrolides, are not sufficient. Appropriate antibiotics for the initial treatment of suspected Acinetobacter infections include imipenem and carboxy- and ureidopenicillins combined with an aminoglycoside.

Molecular Epidemiology of Carbapenem Non-Susceptible Acinetobacter baumannii in France

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Jeannot, Katy; Diancourt, Laure; Vaux, Sophie; Thouverez, Michelle; Ribeiro, Amandina; Coignard, Bruno; Courvalin, Patrice; Brisse, Sylvain

2014-01-01

Carbapenem-resistant Acinetobacter baumannii have emerged globally. The objective of this study was to investigate the epidemiology, clonal diversity and resistance mechanisms of imipenem non-susceptible A. baumannii isolates in France. Between December 2010 and August 2011, 132 notifications were collected, including 37 outbreaks corresponding to 242 cases (2 to 55 per cluster). Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on 110 non-repetitive isolates. Gene bla OXA-23 was the most frequently detected (82%), followed by bla OXA-24 (11%) and bla OXA-58 (7%). Eleven sequence types (ST) were distinguished, among which sequence types ST1, ST2 (64%), ST20, ST25, ST85 and ST107. Isolates from epidemiological clusters had the same ST and resistance genes, indicating probable transmission within centres. In contrast, PFGE types of isolates differed among centres, arguing against transmission among centers. This study provides the first epidemiological snapshot of the population of A. baumannii with reduced susceptibility to carbapenems from France, and further underlines the predominance of international clones. PMID:25517732

Identification of Tet 39, a novel class of tetracycline resistance determinant in Acinetobacter spp. of environmental and clinical origin

DEFF Research Database (Denmark)

Agersø, Yvonne; Guardabassi, L.

2005-01-01

A novel tetracycline resistance determinant named Tet 39 was found in unrelated Acinetobacter strains isolated from freshwater trout farms (n=4) and sewage (n=6) in Denmark, and from a clinical specimen in the Netherlands (n=1). The determinant was located on transferable plasmids and consisted o...

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

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Maraki, Sofia; Mantadakis, Elpis; Mavromanolaki, Viktoria Eirini; Kofteridis, Diamantis P; Samonis, George

2016-09-01

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. 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. 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. Nevertheless, with the exception of colistin

Over expression of AdeABC and AcrAB-TolC efflux systems confers tigecycline resistance in clinical isolates of Acinetobacter baumannii and Klebsiella pneumoniae

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Yin Yuhan

2016-04-01

Full Text Available Abstract: INTRODUCTION: Due to the wide use of tigecycline in the treatment of severe infections caused by multidrug-resistant (MDR bacteria, clinical resistance to tigecycline has increased in recent years. Here, we investigated the relationship between tigecycline resistance and the expression of efflux pumps. METHODS: Clinical isolates of Acinetobacter baumannii and Klebsiella pneumoniae were consecutively collected from hospitalized patients in three hospitals. The minimum inhibitory concentration (MIC of tigecycline was determined using the broth microdilution method. Expression levels of efflux pump genes and regulators were examined by quantitative real-time reverse transcription polymerase chain reaction. The correlations between tigecycline MICs and gene expression levels were analyzed. RESULTS: Overall, 1,026 A. baumannii and 725 K. pneumoniae strains were collected. Most strains were isolated from sputum. The tigecycline resistance rate was 13.4% in A. baumannii isolates and 6.5% in K. pneumoniae isolates. Overexpression of AdeABC and AcrAB-TolC efflux systems was observed found in clinical tigecycline-resistant isolates. The tigecycline MIC had a linear relationship with the adeB expression level in A. baumannii isolates, but not with the acrB expression level in K. pneumoniae isolates. There were significant linear trends in the overexpression of ramA as the tigecycline MIC increased in K. pneumoniae isolates. CONCLUSIONS: Tigecycline resistance in A. baumannii and K. pneumoniae was strongly associated with the overexpression of efflux systems. More studies are needed to elucidate whether there are other regulators that affect the expression of adeB in A. baumannii and how ramA affects the expression of acrB in K. pneumoniae.

Detailed adsorption mechanism of plasmid DNA by newly isolated cellulose from waste flower spikes of Thypa latifolia using quantum chemical calculations.

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Mujtaba, Muhammad; Kaya, Murat; Akyuz, Lalehan; Erdonmez, Demet; Akyuz, Bahar; Sargin, Idris

2017-09-01

Current study was designed to use the newly obtained cellulose from waste flower spikes of Thypa latifolia plant for plasmid DNA adsorption. Cellulose was isolated according to a previously described method including acid and base treatment, and cellulose content was recorded as 17%. T. latifolia cellulose was physicochemically characterized via FT-IR, TGA and SEM techniques. Detailed mechanism of plasmid DNA adsorption by newly isolated cellulose was described using chemical quantum calculations. To check the effect of Cu ++ immobilization on the affinity of cellulose for plasmid DNA, copper ions were immobilized onto T. latifolia cellulose. pUC18 plasmid DNA was used for adsorption studies. Membranes prepared with only T. latifolia cellulose and Cu ++ immobilized T. latifolia cellulose revealed different adsorption ratios as 43.9 and 86.9% respectively. This newly isolated cellulose from waste flower spikes of T. latifolia can be utilized as a suitable carrier for plasmid DNA. Copyright © 2017 Elsevier B.V. All rights reserved.

Production and Characterization of Tannase from a newly isolated bacillus subtilis

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Aftab, M. N.; Mukhtar, H.; Haq, I.

2016-01-01

The work describes the production and characterization of tannase from a newly isolated Bacillus subtilis. The strain was isolated from the garden soil and was capable of producing tannase at particular temperature (41 degree C) and pH (5) in 24 h. Addition of 10 % glucose as a carbon source and 12% tannic acid as an inducer resulted in the improved rate of enzyme production. The enzyme was purified up to 4.86 fold with 96.25% yield. It exhibited optimal temperature and pH tolerance of 45 degree C and 5, respectively. However, the enzyme was found to be notably more functional in a broad range of temperature (20-80 degree C) and pH (3-10). Furthermore it remained remarkably stable at wide range of pH (3-8) and at a higher salt concentration (3M). The shelf life of enzyme was also prolonged and remained stable up to a maximum of 8 months. (author)

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

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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 bla OXA-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 bla OXA-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. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights

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

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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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rapid molecular characterization of Acinetobacter baumannii clones with rep-PCR and evaluation of carbapenemase genes by new multiplex PCR in Hospital District of Helsinki and Uusimaa.

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Tanja Pasanen

Full Text Available Multidrug-resistant Acinetobacter baumannii (MDRAB is an increasing problem worldwide. Prevalence of carbapenem resistance in Acinetobacter spp. due to acquired carbapenemase genes is not known in Finland. The purpose of this study was to examine prevalence and clonal spread of multiresistant A. baumannii group species, and their carbapenemase genes. A total of 55 Acinetobacter isolates were evaluated with repetitive PCR (DiversiLab to analyse clonality of isolates, in conjunction with antimicrobial susceptibility profile for ampicillin/sulbactam, colistin, imipenem, meropenem, rifampicin and tigecycline. In addition, a new real-time PCR assay, detecting most clinically important carbapenemase genes just in two multiplex reactions, was developed. The assay detects genes for KPC, VIM, IMP, GES-1/-10, OXA-48, NDM, GIM-1, SPM-1, IMI/NMC-A, SME, CMY-10, SFC-1, SIM-1, OXA-23-like, OXA-24/40-like, OXA-58 and ISAbaI-OXA-51-like junction, and allows confident detection of isolates harbouring acquired carbapenemase genes. There was a time-dependent, clonal spread of multiresistant A. baumannii strongly correlating with carbapenamase gene profile, at least in this geographically restricted study material. The new carbapenemase screening assay was able to detect all the genes correctly suggesting it might be suitable for epidemiologic screening purposes in clinical laboratories.

A reliable combination method to identification and typing of epidemic and endemic clones among clinical isolates of Acinetobacter baumannii.

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Piran, Arezoo; Shahcheraghi, Fereshteh; Solgi, Hamid; Rohani, Mahdi; Badmasti, Farzad

2017-10-01

The multi-drug resistant (MDR) Acinetobacter baumannii as an important nosocomial pathogen has emerged a global health concern in recent years. In this study, we applied three easier, faster, and cost-effective methods including PCR-based open reading frames (ORFs) typing, sequence typing of bla OXA-51-like and RAPD-PCR method to rapid typing of A. baumannii strains. Taken together in the present study the results of ORFs typing, PCR-sequencing of bla OXA-51-like genes and MLST sequence typing revealed there was a high prevalence (62%, 35/57) of ST2 as international and successful clone which detected among clinical isolates of multi-drug resistant A. baumannii with ORF pattern B and bla OXA-66 gene. Only 7% (4/57) of MDR isolates belonged to ST1 with ORF pattern A and bla OXA-69 gene. Interestingly, we detected singleton ST513 (32%, 18/57) that encoded bla OXA-90 and showed the ORF pattern H as previously isolated in Middle East. Moreover, our data showed RAPD-PCR method can detect divergent strains of the STs. The Cl-1, Cl-2, Cl-3, Cl-4, Cl-10, Cl-11, Cl-12, Cl-13 and Cl-14 belonged to ST2. While the Cl-6, Cl-7, Cl-8 and Cl-9 belonged to ST513. Only Cl-5 belonged to ST1. It seems that the combination of these methods have more discriminatory than any method separately and could be effectively applied to rapid detection of the clonal complex (CC) of A. baumannii strains without performing of MLST or PFGE. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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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.

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

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Chin-Soon Chee

2014-01-01

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

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

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

2014-01-01

Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) of Acinetobacter calcoaceticus strain PHEA-2, respectively. PMID:24892084

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

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

2013-03-15

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

Carbapenem Breakpoints for Acinetobacter baumannii Group: Supporting Clinical Outcome Data from Patients with Bacteremia.

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Lee, Yi-Tzu; Chiang, Mei-Chun; Kuo, Shu-Chen; Wang, Yung-Chih; Lee, I-Hsin; Chen, Te-Li; Yang, Ya-Sung

2016-01-01

The carbapenem breakpoints set by different organizations for Acinetobacter are discordant, but supporting clinical data are lacking. This study aimed to provide the first clinical outcome data to support the carbapenem breakpoints for Acinetobacter baumannii (Ab) group in patients with bacteremia. This study included 117 adults who received carbapenems for treatment of Ab group bacteremia in Taipei Veterans General Hospital over an 8-year period. We analyzed 30-day mortality rates among patient groups acquiring isolates with different carbapenem minimal inhibitory concentrations (MICs). The carbapenem MIC breakpoint derived from classification and regression tree (CART) analysis to delineate the risk of 30-day mortality was between MICs of ≤ 4 mg/L and ≥ 8 mg/L. Mortality rate was higher in patients acquiring isolates with carbapenem MIC ≥ 8 mg/L than ≤ 4 mg/L, by bivariate (54.9% [28/51] vs 25.8% [17/66]; P = 0.003) and survival analysis (P = 0.001 by log-rank test). Multivariate analysis using logistic regression and Cox regression models including severity of illness indices demonstrated that treating patients with Ab group bacteremia caused by isolates with a carbapenem MIC ≥ 8 mg/L with carbapenem was an independent predictor of 30-day mortality (odds ratio, 5.125; 95% confidence interval [CI], 1.946-13.498; P = 0.001, and hazard ratio, 2.630; 95% CI, 1.431-4.834; P = 0.002, respectively). The clinical outcome data confirmed that isolates with MIC ≤ 4 mg/L were susceptible to carbapenem, and those with MIC ≥ 8 mg/L were resistant in patients with Ab group bacteremia.

Pesquisa de Acinetobacter sp e Pseudomonas aeruginosa produtores de metalo-β-lactamase em hospital de emergência de Porto Alegre, Estado do Rio Grande do Sul, Brasil Investigation of metallo-β-lactamase-producing Acinetobacter sp and Pseudomonas aeruginosa at an emergency hospital in Porto Alegre, State of Rio Grande do Sul, Brazil

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Vani Dos Santos Laranjeira

2010-08-01

Full Text Available INTRODUÇÃO: O aparecimento de Pseudomonas aeruginosa e Acinetobacter sp produtores de metalo-β-lactamases (MBLs é um desafio para os hospitais. MÉTODOS: Verificou-se a produção de MBL em cepas clínicas de Pseudomonas aeruginosa e Acinetobacter sp de um hospital de emergência de Porto Alegre pelo método de aproximação de disco e E-test MBL. Os genes bla foram pesquisados pela PCR. RESULTADOS: Duas cepas de Pseudomonas aeruginosa e oito Acinetobacter sp demonstraram fenótipo de MBLs. A amplificação do gene blaSPM-1 confirmou a enzima em P. aeruginosa.. CONCLUSÕES: Deve-se ter cautela ao avaliar testes fenotípicos utilizados na detecção rotineira de metalo-enzima.INTRODUCTION: The appearance of metallo-β-lactamase (MBL-producing Pseudomonas aeruginosa and Acinetobacter sp. is a challenge for hospitals. METHODS: The production of MBL in clinical isolates of Pseudomonas aeruginosa and Acinetobacter sp. From an emergency hospital in Porto Alegre was investigated using the disk approximation test and MBL E-test. The bla genes were determined using PCR. RESULTS: Two strains of Pseudomonas aeruginosa and eight of Acinetobacter sp were shown to be MBL phenotypes. Amplification of the blaSPM-1 gene confirmed the presence of the enzyme in P. aeruginosa. CONCLUSIONS: Caution is needed in evaluating phenotype tests used for routine detection of metallo-β-lactamases.

Isolation and characterization of an n-hexadecane degrading Acinetobacter baumannii KSS1060 from a petrochemical wastewater treatment plant

International Nuclear Information System (INIS)

Shiri, Z.; Kermanshahi, R. K.; Soudi, M. R.; Farajzadeh, D.

2015-01-01

Hydrocarbons are widespread in the environment, but because of the massive utilization of petroleum products, they are nowadays strongly involved in environmental pollution. Bioremediation is the obliging technology for the treatment of hydrocarbon-contaminated sites. Therefore, to investigate the potential of petrochemical hydrocarbon (HC)-degrading indigenous microorganisms in wastewater samples collected from Fajr petrochemical wastewater treatment plants, a strain of Acinetobacter baumannii was isolated from this hydrocarbon-contaminated wastewater and examined for its ability to utilize hexadecane. This strain was capable to grow on n-hexadecane as the sole source of carbon and energy. The ability of the isolate to degrade n-hexadecane was assessed by growth assays and gas chromatography/mass spectrometry analysis. Using GC analysis, it was shown that the strain KSS1060 was able to degrade 62 % of n-hexadecane within 6 days, which mostly (51.6 %) occurred within the first 24 h. Identification of this hexadecane-degrader bacterium was carried out using 16S rDNA sequence analysis. Additionally, characterization of chemical composition of wastewater samples by the use of gas chromatography/mass spectrometry analysis indicated the presence of Hexanal, Benzene methanol, Indanol, 1,2-benzenedicarboxylic acid diethyl ester, diisobutyl phthalate, and Phenol,4,4′-(1-methylethylidene) in the major constituents of wastewater. In conclusion, this study can focus on more cost-efficient applications of native bacterial strains for the large-scale biodegradation of wastewater samples from petrochemical plant in industry, where it causes disturbing problems due to its harmful effects on different organisms and human beings.

Acinetobacter pneumonia: Is the outcome different from the pneumonias caused by other agents

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Edis Ebru

2010-01-01

Full Text Available Background : The principal aim of the present study was to determine whether Acinetobacter spp. pneumonia differs from hospital-acquired pneumonias (HAPs caused by other agents with respect to therapeutic success and survival rate. METHODS : This study includes 140 adult patients diagnosed with HAPs caused by identified etiologic agents between March 2005 and February 2006. These patients were divided into two groups according to the agent responsible for their infection (Acinetobacter spp. [n = 63] or non-Acinetobacter spp. [n = 77]. The groups were compared in terms of risk factors, therapeutic success and six-week survival rates. Results : Previous antibiotic use and the risk of aspiration were independent factors responsible for the development of Acinetobacter spp. pneumonia. Hypoalbuminemia, steroid use and the use of a mechanical ventilator were determined to be mortality-associated independent risk factors for Acinetobacter spp. pneumonia. The clinical success rate at the end of therapy was 41.6% and, at the sixth week, the survival rate was 35% among patients in whom Acinetobacter spp. was the causative agent. Conversely, in the control group, these values were 43 and 32%, respectively ( P > 0.05. We found that the use of the appropriate antibiotics for the treatment of Acinetobacter spp. pneumonia was an important factor in survival ( P < 0.001. Conclusion : The outcomes of Acinetobacter spp. pneumonia do not differ from HAPs associated with non-Acinetobacter spp. in terms of therapeutic success and survival rates.

Infection with Acinetobacter baumannii in an intensive care unit in the Western part of Romania.

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Lăzureanu, Voichița; Poroșnicu, Mirela; Gândac, Ciprian; Moisil, Teodora; Bădițoiu, Luminița; Laza, Ruxandra; Musta, Virgil; Crișan, Alexandru; Marinescu, Adelina-Raluca

2016-03-08

Acinetobacter baumannii is one of the main causes of morbidity and mortality in critical condition patients. The pathogen's ability to survive under a wide range of environment conditions and to persist for long periods of time on areas represents a frequent cause of endemic infection hotbeds especially in the Intensive Care Unit. The objectives of the study are: determining the 5-year incidence of A. baumannii infection in patients admitted in the ICU which needed mechanical ventilation; the analysis of these cases regarding pathological antecedents; processing the data regarding these cases; gradual analysis of the susceptibility/resistance of isolated A. baumannii strains; observing the emergence of A. baumannii infection in patients transferred into the ICU. We have performed an observational retrospective study regarding the incidence of Acinetobacter baumannii infections in the Intensive Care Unit of the Hospital of Infectious Diseases and Pneumophtisiology "Victor Babes" Timisoara, Clinic II Infectious Diseases, during June 2011 - June 2015. We have identified a high prevalence of Acinetobacter baumannii infection, with an average period of 6 days. Bronchial suction was the most common pathological product in the study (90 % of the cases). Resistance to antimicrobials has been determined: the lowest resistance was recorded for ampicillin + sulbactam (81.1 %), and the highest resistance rate was recorded for ceftazidime and imipenem (94.6 % each). When comparing resistance to third generation cephalosporins, the difference was not statistically significant (94.6 % for ceftazidime vs. 86.5 % for cefoperazone, p = 0.117). Within the present study we were able to observe a significantly high resistance of the germ to carbapenems, with a good sensitivity to aminoglycosides, and to colistin. Only one strain of Acinetobacter baumannii was resistant to all classes of tested antibiotics. Generally, carbapenems represented the elective treatment in

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

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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.

Extracellular laccase production and phenolic degradation by an olive mill wastewater isolate

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R. Kumar

2018-03-01

Full Text Available Olive mill wastewater (OMWW presents a challenge to the control of effluents due to the presence of a high organic load, antimicrobial agents (monomeric-polymeric phenols, volatile acids, polyalcohols, and tannins, salinity and acidity. In this study, the production of extracellular laccase, monomeric or polymeric phenol, from an OMWW isolate based on its ability to biodegrade phenols and gallic acid as a model of phenolic compounds in OMWW was investigated. Phylogenetic analysis of the 16S RNA gene sequences identified the bacterial isolate (Acinetobacter REY as being closest to Acinetobacter pittii. This isolate exhibited a constitutive production of extracellular laccase with an activity of 1.5 and 1.3 U ml/L when supplemented with the inducers CuSO4 and CuSO4+phenols, respectively. Batch experiments containing minimal media supplemented with phenols or gallic acid as the sole carbon and energy source were performed in order to characterize their phenolic biodegradability. Acinetobacter REY was capable of biodegrading up to 200 mg/L of phenols and gallic acid both after 10 h and 72 h, respectively.

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

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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

The mazEF toxin-antitoxin system as a novel antibacterial target in Acinetobacter baumannii.

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Ghafourian, Sobhan; Good, Liam; Sekawi, Zamberi; Hamat, Rukman Awang; Soheili, Sara; Sadeghifard, Nourkhoda; Neela, Vasanthakumari

2014-07-01

Although analysis of toxin-antitoxin (TA) systems can be instructive, to date, there is no information on the prevalence and identity of TA systems based on a large panel of Acinetobacter baumannii clinical isolates. The aim of the current study was to screen for functional TA systems among clinical isolates of A. baumannii and to identify the systems' locations. For this purpose, we screened 85 A. baumannii isolates collected from different clinical sources for the presence of the mazEF, relBE and higBA TA genes. The results revealed that the genes coding for the mazEF TA system were commonly present in all clinical isolates of A. baumannii. Reverse transcriptase-polymerase chain reaction analysis showed that transcripts were produced in the clinical isolates. Our findings showed that TA genes are prevalent, harboured by chromosomes and transcribed within A. baumannii. Hence, activation of the toxin proteins in the mazEF TA system should be investigated further as an effective antibacterial strategy against this bacterium.

Clinical and antimicrobial profile of Acinetobacter spp.: An emerging nosocomial superbug

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Purti C Tripathi

2014-01-01

Conclusion: Acinetobacter nosocomial infections resistant to most antimicrobials have emerged, especially in ICU. Early identification and continued surveillance of prevalent organism will help prevent the spread of Acinetobacter in hospital environment.

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

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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.

Virulence profiles and innate immune responses against highly lethal, multidrug-resistant nosocomial isolates of Acinetobacter baumannii from a tertiary care hospital in Mexico

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Gayosso-Vázquez, Catalina; Fernández-Vázquez, José Luis; Jarillo-Quijada, Ma Dolores; Rivera-Benítez, César; Santos-Preciado, José Ignacio

2017-01-01

Virulence profiles and innate immune responses were studied in Acinetobacter baumannii from nosocomial infections collected over one year in a tertiary care hospital in Mexico. A. baumannii were identified by VITEK 2 System followed by susceptibility tests. Carbapenemase genes, active efflux mechanism to imipenem and meropenem and outer membrane proteins profile were analyzed to evaluate their role on the activity of carbapenem resistance. All isolates were genotyped by pulsed field gel electrophoresis. The ability to form biofilm was determined on a polystyrene surface. The resistance to complement was determined with a pooled human normal serum and TNFα release by infected macrophages was determined by ELISA. The 112 isolates from this study were associated with a 52% of mortality. All were resistance to β-lactams, fluoroquinolones, and trimethroprim-sulfamethoxal, 96 and 90% were resistant to meropenem and imipenem, respectively, but with high susceptibility to polymyxin B, colistin and tigecyclin. Isolates were classified in 11 different clones. Most isolates, 88% (99/112), were metallo-β-lactamases and carbapenemases producers, associated in 95% with the presence of blaOXA-72 gene. Only 4/99 and 1/99 of the carbapenem-resistant isolates were related to efflux mechanism to meropenem or imipenem resistance, respectively. The loss of expression of 22, 29, and/or 33-36-kDa proteins was detected in 8/11 of the clinical isolates with resistance to carbapenem. More than 96% (108/112) of the isolates were high producers of biofilms on biotic surfaces. Finally, all isolates showed variable resistance to normal human serum activity and were high inductors of TNFα release by macrophages. In summary, these results suggest that multidrug-resistant A. baumannii can persist in the hospital environment through its ability to form biofilms. The high mortality observed was due to their ability to survive normal human serum activity and capability to induce potent

Epidemiological characteristics of blaNDM-1 in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex in China from 2011 to 2012.

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Weimei Ou

Full Text Available The study aimed to investigate the prevalence and epidemiological characteristics of blaNDM-1 (encoding New Delhi metallo-β-lactamase 1 in Enterobacteriaceae and the Acinetobacter calcoaceticus-Acinetobacter baumannii complex (ABC in China from July 2011 to June 2012.PCR was used to screen for the presence of blaNDM-1 in all organisms studied. For blaNDM-1-positive strains, 16S rRNA analysis and Analytical Profile Index (API strips were used to identify the bacterial genus and species. The ABCs were reconfirmed by PCR detection of blaOXA-51-like. Antibiotic susceptibilities of the bacteria were assessed by determining minimum inhibitory concentration (MIC of them using two-fold agar dilution test, as recommended by the Clinical and Laboratory Standards Institute (CLSI. Molecular typing was performed using pulsed-field gel electrophoresis (PFGE. S1 nuclease-pulsed-field gel electrophoresis (S1-PFGE and Southern blot hybridization were conducted to ascertain the gene location of blaNDM-1. Conjugation experiments were conducted to determine the transmission of blaNDM-1-positive strains.Among 2,170 Enterobacteriaceae and 600 ABCs, seven Enterobacteriaceae strains and two A. calcoaceticus isolates from five different cities carried the blaNDM-1 gene. The seven Enterobacteriaceae strains comprised four Klebsiella pneumoniae, one Enterobacter cloacae, one Enterobacter aerogen and one Citrobacter freundii. All seven were non-susceptible to imipenem, meropenem or ertapenem. Two A. calcoaceticus species were resistant to imipenem and meropenem. Three K. pneumoniae showed the same PFGE profiles. The blaNDM-1 genes of eight strains were localized on plasmids, while one was chromosomal.Compared with previous reports, the numbers and species containing the blaNDM-1 in Enterobacteriaceae have significantly increased in China. Most of them are able to disseminate the gene, which is cause for concern. Consecutive surveillance should be implemented and should

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

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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.

Real-Time Fluorescence Loop Mediated Isothermal Amplification for the Detection of Acinetobacter baumannii

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Wang, Qinqin; Zhou, Yanbin; Li, Shaoli; Zhuo, Chao; Xu, Siqi; Huang, Lixia; Yang, Ling; Liao, Kang

2013-01-01

Background Detection of Acinetobacter baumannii has been relying primarily on bacterial culture that often fails to return useful results in time. Although DNA-based assays are more sensitive than bacterial culture in detecting the pathogen, the molecular results are often inconsistent and challenged by doubts on false positives, such as those due to system- and environment-derived contaminations. In addition, these molecular tools require expensive laboratory instruments. Therefore, establishing molecular tools for field use require simpler molecular platforms. The loop-mediated isothermal amplification method is relatively simple and can be improved for better use in a routine clinical bacteriology laboratory. A simple and portable device capable of performing both the amplification and detection (by fluorescence) of LAMP in the same platform has been developed in recent years. This method is referred to as real-time loop-mediated isothermal amplification. In this study, we attempted to utilize this method for rapid detection of A. baumannii. Methodology and Significant Findings Species-specific primers were designed to test the utility of this method. Clinical samples of A. baumannii were used to determine the sensitivity and specificity of this system compared to bacterial culture and a polymerase chain reaction method. All positive samples isolated from sputum were confirmed to be the species of Acinetobacter by 16S rRNA gene sequencing. The RealAmp method was found to be simpler and allowed real-time detection of DNA amplification, and could distinguish A. baumannii from Acinetobacter calcoaceticus and Acinetobacter genomic species 3. DNA was extracted by simple boiling method. Compared to bacterial culture, the sensitivity and specificity of RealAmp in detecting A. baumannii was 98.9% and 75.0%, respectively. Conclusion The RealAmp assay only requires a single unit, and the assay positivity can be verified by visual inspection. Therefore, this assay has

Characterization of a highly virulent and antimicrobial-resistant Acinetobacter baumannii strain isolated from diseased chicks in China.

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Liu, Dong; Liu, Zeng-Shan; Hu, Pan; Hui, Qi; Fu, Bao-Quan; Lu, Shi-Ying; Li, Yan-Song; Zou, De-Ying; Li, Zhao-Hui; Yan, Dong-Ming; Ding, Yan-Xia; Zhang, Yuan-Yuan; Zhou, Yu; Liu, Nan-Nan; Ren, Hong-Lin

2016-08-01

Poultry husbandry is a very important aspect of the agricultural economy in China. However, chicks are often susceptible to infectious disease microorganisms, such as bacteria, viruses and parasites, causing large economic losses in recent years. In the present study, we isolated an Acinetobacter baumannii strain, CCGGD201101, from diseased chicks in the Jilin Province of China. Regression analyses of virulence and LD50 tests conducted using healthy chicks confirmed that A. baumannii CCGGD201101, with an LD50 of 1.81 (±0.11) × 10(4) CFU, was more virulent than A. baumannii ATCC17978, with an LD50 of 1.73 (±0.13) × 10(7) CFU. Moreover, TEM examination showed that the pili of A. baumannii CCGGD201101 were different from those of ATCC17978. Antibiotic sensitivity analyses showed that A. baumannii CCGGD201101 was sensitive to rifampicin but resistant to most other antibiotics. These results imply that A. baumannii strain CCGGD201101 had both virulence enhancement and antibiotic resistance characteristics, which are beneficial for A. baumannii survival under adverse conditions and enhance fitness and invasiveness in the host. A. baumannii CCGGD20101, with its high virulence and antimicrobial resistance, may be one of the pathogens causing death of diseased chicks. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

Extremophilic Acinetobacter Strains from High-Altitude Lakes in Argentinean Puna: Remarkable UV-B Resistance and Efficient DNA Damage Repair

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Albarracín, Virginia Helena; Pathak, Gopal P.; Douki, Thierry; Cadet, Jean; Borsarelli, Claudio Darío; Gärtner, Wolfgang; Farias, María Eugenia

2012-06-01

High-Altitude Andean Lakes (HAAL) of the South American Andes are almost unexplored ecosystems of shallow lakes. The HAAL are recognized by a remarkably high UV exposure, strong changes in temperature and salinity, and a high content of toxic elements, especially arsenic. Being exposed to remarkably extreme conditions, they have been classified as model systems for the study of life on other planets. Particularly, Acinetobacter strains isolated from the HAAL were studied for their survival competence under strong UV-B irradiation. Clinical isolates, Acinetobacter baumannii and Acinetobacter johnsonii, served as reference material. Whereas the reference strains rapidly lost viability under UV-B irradiation, most HAAL-derived strains readily survived this exposure and showed less change in cell number after the treatment. Controls for DNA repair activity, comparing dark repair (DR) or photo repair (PR), gave evidence for the involvement of photolyases in the DNA repair. Comparative measurements by HPLC-mass spectrometry detected the number of photoproducts: bipyrimidine dimers under both PR and DR treatments were more efficiently repaired in the HAAL strains (up to 85 % PR and 38 % DR) than in the controls (31 % PR and zero DR ability). Analysis of cosmid-cloned total genomic DNA from the most effective DNA-photorepair strain (Ver3) yielded a gene (HQ443199) encoding a protein with clear photolyase signatures belonging to class I CPD-photolyases. Despite the relatively low sequence similarity of 41 % between the enzymes from Ver3 and from E. coli (PDB 1DNPA), a model-building approach revealed a high structural homology to the CPD-photolyase of E. coli.

CipA of Acinetobacter baumannii Is a Novel Plasminogen Binding and Complement Inhibitory Protein.

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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. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Production and partial characterization of lipases from a newly isolated Penicillium sp. using experimental design.

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Wolski, E; Rigo, E; Di Luccio, M; Oliveira, J V; de Oliveira, D; Treichel, H

2009-07-01

The objective of this work was to investigate the lipase production by a newly isolated Penicillium sp., using experimental design technique, in submerged fermentation using a medium based on peptone, yeast extract, NaCl and olive oil, as well as to characterize the crude enzymatic extracts obtained. Lipase activity values of 9.5 U ml(-1) in 96 h of fermentation was obtained at the maximized operational conditions of peptone, yeast extract, NaCl and olive oil concentrations (g l(-1)) of 20.0, 5.0, 5.0 and of 10.0 respectively. The partial characterization of crude enzymatic extract obtained by submerged fermentation showed optimum activity at pH range from 4.9 to 5.5 and temperature from 37 degrees C to 42 degrees C. The crude extract maintained its initial activity at freezing temperatures up to 100 days. A newly isolated strain of Penicillium sp. used in this work yielded good lipase activities compared to the literature. The growing interest in lipase production is related to the potential biotechnological applications that these enzymes present. New lipase producers are relevant to finding enzymes with different catalytic properties of commercial interest could be obtained, without using genetically modified organisms (GMO).

Related structures of neutral capsular polysaccharides of Acinetobacter baumannii isolates that carry related capsule gene clusters KL43, KL47, and KL88.

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Shashkov, Alexander S; Kenyon, Johanna J; Arbatsky, Nikolay P; Shneider, Mikhail M; Popova, Anastasiya V; Miroshnikov, Konstantin A; Hall, Ruth M; Knirel, Yuriy A

2016-11-29

Capsular polysaccharides were recovered from four Acinetobacter baumannii isolates, and the following related structures of oligosaccharide repeating units were established by sugar analyses along with 1D and 2D 1 H and 13 C NMR spectroscopy: NIPH 60 and LUH5544 (K43) NIPH 601 (K47) The K locus for capsule biosynthesis in the genome sequences available for NIPH 60 and LUH5544, designated KL43, was found to be related to gene clusters KL47 in NIPH 601 and KL88 in LUH5548. The three clusters share most gene content differing in only a small portion that includes an additional glycosyltransferase genes in KL47 and KL88, as well as genes encoding distinct Wzy polymerases that were found to form the same α-d-GlcpNAc-(1 → 6)-α-d-GlcpNAc linkage in K43 and K47. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quorum sensing signal profile of Acinetobacter strains from nosocomial and environmental sources Perfil de sensores de quórum en cepas nosocomiales y ambientales de Acinetobacter

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R. H. González

2009-06-01

Full Text Available A set of 43 strains corresponding to 20 classified and unclassified genomic Acinetobacter species was analyzed for the production of typical N-acyl homoserine lactone quorum sensing molecules in culture broths. A large percentage of the strains (74% displayed quorum sensing signals that could be separated into three statistically significantly different chromatographic groups (p Rf2 > Rf1. None of the three signals could be specifically assigned to a particular species in the genus; furthermore, no distinction could be made between the quorum sensing signals secreted by typical opportunistic strains of the A. calcoaceticus-A. baumannii complex, isolated from patients, with respect to the other species of the genus, except for the Rf1 signal which was present in all the QS positive strains belonging to this complex and DNA group 13 TU. In conclusion, quorum sensors in Acinetobacter are not homogenously distributed among species and one of them is present in most of the A. calcoaceticus-baumannii complex.Se analizó la producción de moléculas típicas de N-acil homoserina lactona con actividad de quorum sensing en cultivos líquidos de un grupo de 43 cepas correspondientes a 20 especies genómicas clasificadas y no clasificadas de Acinetobacter. Un porcentaje alto de las cepas (74% mostraron señales de quorum sensing que pudieron ser separadas en tres grupos cromatográficos significativamente diferentes entre sí (p Rf2 > Rf1. Ninguna de las tres señales pudo ser asignada a una especie en particular dentro del género; es más, no se encontró diferencia entre las señales producidas por las cepas típicamente oportunistas (complejo A. calcoaceticus-A. baumannii aisladas de pacientes respecto de las producidas por otras cepas del mismo género, excepto para el caso de Rf1, que se encontró presente en todos los aislamientos quorum sensing positivos del mencionado complejo y en las cepas del grupo de DNA 13TU. En conclusión, los sensores de

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

NARCIS (Netherlands)

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

2017-01-01

Acinetobacter baumannii is an important cause of multidrug-resistant hospital acquired infections in the world. Here, we investigate the presence of NDM-1 and other carbapenemases among carbapenem-resistant A. baumannii isolated between August 2010 and December 2014 from three large hospitals in

Prevalence of multi drug resistant Acinetobacter baumannii in the clinical samples from Tertiary Care Hospital in Islamabad, Pakistan.

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Begum, Shahzeera; Hasan, Fariha; Hussain, Shagufta; Ali Shah, Aamer

2013-09-01

Acinetobacter baumannii can cause a wide range of infections, including bacteremia, pneumonia, urinary tract infection, peritonitis, etc. This organism is becoming resistant to a large group of antibiotics, especially β-lactam antibiotics. The reason for multi-drug resistance may be the production of extended- spectrum β-lactamses (ESBLs), carbapenemases/metallo β-lactamases or AmpC β-lactamases. The aim of the present study was to determine the prevalence of multi-drug resistant Acinetobacter baumannii isolated from the patients in Surgical Intensive Care Units (SICUs) of Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan. A total of 91 A. baumanni isolates were collected from PIMS during the period from February 2011 to December 2011. The antibiotic susceptibility testing was performed by standard disc diffusion method as recommended by CLSI. Combination disc method, Modified Hodge test, EDTA disc synergy test and AmpC disc test were performed for detection of ESBLs, carbapenemases, metallo β-lactamases, and AmpC β-lactamases, respectively. The prevalence of MDRs was reported 100% among A. baumannii. The antibiotic susceptibility profile showed that minocycline and tigecycline were the most effective drugs against A. baumannii. Almost all of A. baumannii isolates were carbapenemase and metallo β-lactamase producers. AmpC prevalence was observed in 41.76%, while none of the isolates was ESBL producer. Antibiogram and minimal inhibitory concentrations (MICs) indicated tetracycline is relatively effective against A. baumanii. Increased frequency of multi-drug resistance supports the need for continuous surveillance to determine prevalence and evolution of these enzymes in Pakistan.

Identification of antigens from nosocomial Acinetobacter baumannii clinical isolates in sera from ICU staff and infected patients using the antigenome technique.

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Nafarieh, Tina; Bandehpour, Mojgan; Hashemi, Ali; Taheri, Sodabeh; Yardel, Vahid; Jamaati, Hamidreza; Moosavi, Seyed Mahdi; Mosaffa, Nariman

2017-09-30

Nosocomial infections with a bacterial origin are considered one of the most dangerous threats to global health. Among the causes of these infections, Acinetobacter baumannii is playing a significant role, and the present study aimed‏ to determine the immunogenic proteins of this bacteria. Clinical isolates of A. baumannii were obtained from positive sputum cultures of intensive care unit (ICU) patients confirmed by Polymerase chain reaction (PCR) of the OXA-51 gene, and sera was obtained from 20 colonized patients. In addition, 20 and 30 serum samples were collected from ICU nurses and healthy controls, respectively. All the samples were screened in the presence of antibodies against A. baumannii by enzyme-linked immunosorbent assay (ELISA). IgG purified from the serum samples by affinity chromatography was used to isolate the bacteria by the Magnetic-activated cell sorting (MACS) procedure. After the bacteria were cultured, the identified antigen proteins were studied by western blotting and Mass spectrometry (MS). The MS results were analyzed with MASCOT software and revealed a 35 KD protein, which corresponds to outer membrane protein A (OmpA) of A. baumannii, a 25 KD band, which is a carbapenem-associated resistance protein precursor, and a 60 KD protein band, identified as a stress-induced bacterial acidophilic repeat motif protein. According to the properties of immunogen antigens and bio informatics tools, the outer membrane proteins (OMPs) can be used as a vaccine candidate in animal models.

The mazEF toxin-antitoxin system as a novel antibacterial target in Acinetobacter baumannii

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Sobhan Ghafourian

2014-07-01

Full Text Available Although analysis of toxin-antitoxin (TA systems can be instructive, to date, there is no information on the prevalence and identity of TA systems based on a large panel of Acinetobacter baumannii clinical isolates. The aim of the current study was to screen for functional TA systems among clinical isolates of A. baumannii and to identify the systems’ locations. For this purpose, we screened 85 A. baumannii isolates collected from different clinical sources for the presence of the mazEF, relBE and higBA TA genes. The results revealed that the genes coding for the mazEF TA system were commonly present in all clinical isolates of A. baumannii. Reverse transcriptase-polymerase chain reaction analysis showed that transcripts were produced in the clinical isolates. Our findings showed that TA genes are prevalent, harboured by chromosomes and transcribed within A. baumannii. Hence, activation of the toxin proteins in the mazEF TA system should be investigated further as an effective antibacterial strategy against this bacterium.

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

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Nielsen, Travis B.; Bonomo, Robert A.; Pantapalangkoor, Paul; Luna, Brian; Spellberg, Brad

2016-01-01

SUMMARY Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)–Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed. PMID:27974412

A medically relevant capsular polysaccharide in Acinetobacter baumannii is a potential vaccine candidate.

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Yang, Feng-Ling; Lou, Tze-Chi; Kuo, Shu-Chen; Wu, Wan-Ling; Chern, Jeffy; Lee, Yi-Tzu; Chen, Shui-Tsung; Zou, Wei; Lin, Nien-Tsung; Wu, Shih-Hsiung

2017-03-07

Concerns of Acinetobacter baumannii infection have increased due to the emergence of multi-drug resistance. In the present study, we determined the capsular polysaccharide (CPS) structure of A. baumannii SK44, a clinical isolate from Taiwan, to consist of pentasaccharide repeats. We found that CPS-induced antibody provided 55% protection against challenge in an animal model. The CPS-specific antibody reacted with the surface components of about 62% clinical isolates (342/554 strains) from cross-sectional and longitudinal studies by dot-immunoassay. Pulsed-field gel electrophoresis of positive strains showed the antibody covered different clonalites of A. baumannii clinical isolates. Meanwhile, using the CPS antibody as a probe, we found a number of outer membrane proteins bound to the antibody, including OmpA/motB, TonB-dependent receptor, and Omp38, indicating their association with CPS. These results might lead to the use of the capsular polysaccharide as a vaccine to prevent A. baumannii infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

A five year study on the susceptibility of isolates from various parts of ...

African Journals Online (AJOL)

STORAGESEVER

2008-10-06

Oct 6, 2008 ... faecalis 200, Enterobacter aerogenes 175, Acinetobacter baumannii 150, Proteus vulgaris 110,. Providencia stuartii 101, Streptococcus pneumoniae 16, Citrobacter freundii 51. The isolates varied widely in their susceptibility pattern. Almost all the isolates were about 100% resistant to cloxacillin,.

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.

Epidemiology of Multiresistant Acinetobacter Infections in Bulgaria

International Nuclear Information System (INIS)

Savov, E.; Borisova, M.; Michailova, G.

2007-01-01

Evolution of bacteria towards resistance to antimicrobial drugs, including these with multidrug resistance, is very important issue for hospital epidemiology in all over the world. There are many papers about an increasing number of Acinetobacter baumannii blood stream and other type of infections in patients at military medical facilities in the Iraq / Kuwait region and in Afghanistan during Operation Enduring Freedom /OEF /. It has now become also a one of the major cause of hospital acquired infections in Bulgaria which due to its remarkable propensity to rapidly acquire resistance determinants to a wide range of antimicrobial drugs. According to the data obtained in Bulgaria, it can be concluded that the majority of the A.baumannii isolates was strikingly resistant, including the 3rd generation of cephalosporins, quinolones and also carbapenems, in the last years. Different methods / phenotypical and molecular methods, including PCR/ for a multidrug A.baumannii investigation and its clonality determination are needed, especially when the strains are not epidemiological related.(author)

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

OpenAIRE

Vajihe Karbasizade; Leila Heidari; Reyhaneh Jafari

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...

Antibacterial activity of epigallocatechin-3-gallate (EGCG) and its synergism with β-lactam antibiotics sensitizing carbapenem-associated multidrug resistant clinical isolates of Acinetobacter baumannii.

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Lee, Spencer; Razqan, Ghaida Saleh Al; Kwon, Dong H

2017-01-15

Infections caused by Acinetobacter baumannii were responsive to conventional antibiotic therapy. However, recently, carbapenem-associated multidrug resistant isolates have been reported worldwide and present a major therapeutic challenge. Epigallocatechin-3-Gallate (EGCG) extracted from green tea exhibits antibacterial activity. We evaluated the antibacterial activity of EGCG and possible synergism with antibiotics in carbapenem-associated multidrug resistant A. baumannii. A potential mechanism for synergism was also explored. Seventy clinical isolates of A. baumannii collected from geographically different areas were analyzed by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EGCG. Checkerboard and time-killing assays were performed to exam the synergism between EGCG and antibiotics. The effects of EGCG on a multidrug efflux pump inhibitor (1-[1-naphthylmethyl] piperazine; NMP) and β-lactamase production were also examined in A. baumannii. Sixty-three of 70 clinical isolates of A. baumannii carried carbapenemase-encoding genes with carbapenem-associated multidrug resistance. Levels of MIC and MBC of EGCG ranged from 64 to 512µg/ml and from 128 to ≥1024µg/ml, respectively among the clinical isolates. MIC 90 and MBC 86 levels were 256µg/ml and 512µg/ml of EGCG, respectively. Subinhibitory concentration of EGCG in combination with all antibiotics tested, including carbapenem, sensitized (MICs fall≤1.0µg/ml) all carbapenem-associated multidrug resistant isolates. Checkerboard and time-killing assays showed synergism between EGCG and meropenem (or carbenicillin) counted as fractional inhibitory concentration of 2log10 within 12h, respectively. EGCG significantly increased the effect of NMP but was unrelated to β-lactamase production in A. baumannii, suggesting EGCG may be associated with inhibition of efflux pumps. Overall we suggest that EGCG-antibiotic combinations might provide an alternative approach to treat

Delayed identification of Acinetobacter baumannii during an outbreak owing to disrupted blaOXA-51-like by ISAba19.

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Ahmadi, Amjad; Salimizand, Himen

2017-07-01

Early detection of Acinetobacter baumannii, an emerging pathogen in hospital settings, is of interest. The bla OXA-51-like family had been used as a marker to detect A. baumannii. During an infection outbreak, 14 isolates produced a 1.7-kb PCR band instead of 353 bp for this marker. This work sought the reasons behind the increased marker size. Characterisation of isolates was done by API-20NE, gyrB multiplex PCR and 16S-23S rRNA ITS sequencing. The 1.7-kb band generated and the complete bla OXA-51-like variant were sequenced to find the probable integrated element. Susceptibility testing to various antimicrobials was performed by microdilution. bla OXA-like , metallo-β-lactamases (MBLs), the ISAba1 element and the presence of ISAba1 adjacent to bla OXA-like were sought. rep-PCR, global clonal (GC) lineage determination and multilocus sequence typing (MLST) were performed to analyse the relationship among isolates. Isolates were characterised as Acinetobacter baumannii-calcoaceticus complex by API-20NE. gyrB multiplex PCR and 16S-23S ITS sequencing verified the isolates as A. baumannii. Sequencing of the 1.7-kb band revealed ISAba19 as the disrupting element. The bla OXA-51 variant was bla OXA-66 , which was elongated to 2.2 kb due to ISAba19. The bla OXA-23-like family was found in 67% of isolates. MBL genes were not detected; however, ISAba1-bla OXA-23-like was characterised in carbapenem-resistant isolates (53%; 8/15). Isolates were divided into three clusters by rep-PCR. All strains were ST2 and all but one belonged to GC II. Identification of A. baumannii based only on bla OXA-51-like is not reliable. Besides bla OXA-51-like , multiplex PCR of gyrB and rpoB could provide rapid and cost-effective results. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

The Environmental Acinetobacter baumannii Isolate DSM30011 Reveals Clues into the Preantibiotic Era Genome Diversity, Virulence Potential, and Niche Range of a Predominant Nosocomial Pathogen

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Viale, Alejandro M.; Borges, Vítor; Cameranesi, María M.; Taib, Najwa; Espariz, Martín; Brochier-Armanet, Céline; Gomes, João Paulo; Salcedo, Suzana P.

2017-01-01

Abstract Acinetobacter baumannii represents nowadays an important nosocomial opportunistic pathogen whose reservoirs outside the clinical setting are obscure. Here, we traced the origins of the collection strain A. baumannii DSM30011 to an isolate first reported in 1944, obtained from the enriched microbiota responsible of the aerobic decomposition of the resinous desert shrub guayule. Whole-genome sequencing and phylogenetic analysis based on core genes confirmed DSM30011 affiliation to A. baumannii. Comparative studies with 32 complete A. baumannii genomes revealed the presence of 12 unique accessory chromosomal regions in DSM30011 including five encompassing phage-related genes, five containing toxin genes of the type-6 secretion system, and one with an atypical CRISPRs/cas cluster. No antimicrobial resistance islands were identified in DSM30011 agreeing with a general antimicrobial susceptibility phenotype including folate synthesis inhibitors. The marginal ampicillin resistance of DSM30011 most likely derived from chromosomal ADC-type ampC and blaOXA-51-type genes. Searching for catabolic pathways genes revealed several clusters involved in the degradation of plant defenses including woody tissues and a previously unreported atu locus responsible of aliphatic terpenes degradation, thus suggesting that resinous plants may provide an effective niche for this organism. DSM30011 also harbored most genes and regulatory mechanisms linked to persistence and virulence in pathogenic Acinetobacter species. This strain thus revealed important clues into the genomic diversity, virulence potential, and niche ranges of the preantibiotic era A. baumannii population, and may provide an useful tool for our understanding of the processes that led to the recent evolution of this species toward an opportunistic pathogen of humans. PMID:28934377

Variation in the complex carbohydrate biosynthesis loci of Acinetobacter baumannii genomes.

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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.

Screening and characterization of a novel alkaline lipase from Acinetobacter calcoaceticus 1-7 isolated from Bohai Bay in China for detergent formulation

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Haikuan Wang

2012-03-01

Full Text Available A novel alkaline lipase-producing strain 1-7 identified as Acinetobacter calcoaceticus was isolated from soil samples collected from Bohai Bay, China, using an olive oil alkaline plate, which contained olive oil as the sole carbon source. The lipase from strain 1-7 showed the maximum activity at pH 9.0 under 40ºC. One interesting feature of this enzyme is that it exhibits lipase activity over a broad range of temperatures and good stability. It is also stable at a broad range of pHs from 4.0 to 10.0 for 24 h. Its catalytic activity was highly enhanced in the presence of Ca2+, Mg2+ and K+, but partially inhibited by Cu2+, Al3+, Fe3+ , Ba2+and Zn2+. The fact that it displays marked stability and activity in the presence of TritonX-100, Tween-20, Tween-80, SDS, Hydrogen peroxide, Sodium perborate, Sodium hypochlorite, Sodium citrate, Sodium taurocholate, Glycerine and NaCl suggests that this lipase is suitable as an additive in detergent formulations.

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

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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

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

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Seyedeh Nasim Karimipour

2016-09-01

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

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

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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.

Acinetobacter: environmental and biotechnological applications ...

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Among microbial communities involved in different ecosystems such as soil, freshwater, wastewater and solid wastes, several strains belonging to the genus of Acinetobacter have been attracting growing interest from medical, environmental and a biotechnological point of view. Bacteria of this genus are known to be ...

Acinetobacter species as model microorganisms in environmental microbiology: current state and perspectives.

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Jung, Jaejoon; Park, Woojun

2015-03-01

Acinetobacter occupies an important position in nature because of its ubiquitous presence in diverse environments such as soils, fresh water, oceans, sediments, and contaminated sites. Versatile metabolic characteristics allow species of this genus to catabolize a wide range of natural compounds, implying active participation in the nutrient cycle in the ecosystem. On the other hand, multi-drug-resistant Acinetobacter baumannii causing nosocomial infections with high mortality has been raising serious concerns in medicine. Due to the ecological and clinical importance of the genus, Acinetobacter was proposed as a model microorganism for environmental microbiological studies, pathogenicity tests, and industrial production of chemicals. For these reasons, Acinetobacter has attracted significant attention in scientific and biotechnological fields, but only limited research areas such as natural transformation and aromatic compound degradation have been intensively investigated, while important physiological characteristics including quorum sensing, motility, and stress response have been neglected. The aim of this review is to summarize the recent achievements in Acinetobacter research with a special focus on strain DR1 and to compare the similarities and differences between species or other genera. Research areas that require more attention in future research are also suggested.

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

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Saghi; Bahador; Khaledi; Ataee Kachoei; Amiri Dastjerdi; Esmaeili

2015-01-01

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 Esc...

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

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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. © 2015 APMIS. Published by John Wiley & Sons Ltd.

Ethanol production from biodiesel-derived crude glycerol by newly isolated Kluyvera cryocrescens

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Choi, Won Jae; Hartono, Maria Regina; Chan, Weng Heng; Yeo, Suan Siong [Agency for Science, Technology and Research (A*STAR), Jurong Island (Singapore). Inst. of Chemical and Engineering Sciences

2011-02-15

The rapidly expanding market for biodiesel has increased the supply and reduced the cost of glycerol, making it an attractive sustainable feed stock for the fuel and chemical industry. Glycerol-based biorefinery is the microbial fermentation of crude glycerol to produce fuels and chemicals. A major challenge is to obtain microbes tolerant to inhibitors such as salts and organic solvents present in crude glycerol. Microbial screening was attempted to isolate novel strain capable of growing on crude glycerol as a sole carbon source. The newly isolated bacteria, identified as nonpathogenic Kluyvera cryocrescens S26 could convert biodiesel-derived crude glycerol to ethanol with high yield and productivity. The supplementation of nutrients such as yeast extract resulted in distinguished enhancement in cell growth as well as ethanol productivity under anaerobic condition. When glycerol fermentation is performed under microaerobic condition, there is also a remarkable improvement in cell growth, ethanol productivity and yield, compared with those under strict anaerobic condition. In batch fermentation under microaerobic condition, K. cryocrescens S26 produced 27 g/l of ethanol from crude glycerol with high molar yield of 80% and productivity of 0.61 g/l/h. (orig.)

Acinetobacter baumannii isolate BAL_212 from Vietnam produces the K57 capsular polysaccharide containing a rarely occurring amino sugar N-acetylviosamine.

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Kenyon, Johanna J; Kasimova, Anastasiya A; Shashkov, Alexander S; Hall, Ruth M; Knirel, Yuriy A

2018-02-01

The structures of capsular polysaccharides (CPSs) produced by different Acinetobacter baumannii strains have proven to be invaluable in confirming the role of specific genes in the synthesis of rare sugars through the correlation of genetic content at the CPS biosynthesis locus with sugars found in corresponding CPS structures. A module of four genes (rmlA, rmlB, vioA and vioB) was identified in the KL57 capsule biosynthesis gene cluster of A. baumannii isolate BAL_212 from Vietnam. These genes were predicted to direct the synthesis of 4-acetamido-4,6-dideoxy-d-glucose (N-acetylviosamine, d-Qui4NAc) and the K57 CPS was found to contain this monosaccharide. The K57 structure was determined and, in addition to d-Qui4NAc, included three N-acetylgalactosamine residues in the main chain, with a single glucose side branch. The KL57 gene cluster has not been found in any other A. baumannii genomes, but the rmlA-rmlB-vioA-vioB module is present in the KL119 gene cluster that would likely produce a d-Qui4NAc-containing CPS.

Isolation, Genome Phylogenetic Analysis and In vitro Rescue of a Newly Emerging Porcine Circovirus Type 2

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Weijuan Zhu and Xiaofeng Ren*

2012-05-01

Full Text Available Porcine circovirus type 2 (PCV2 is the major causative agent of post-weaning multisystemic wasting syndrome (PMWS. Infection by PCV2 may cause heavy losses in pig industry. In this study, we report the isolation of a newly emerging PCV2 from northeastern China. The complete genome of the PCV2 isolate named PCV2-LJR contains 1766 nucleotides and was compared with reference sequences published in GenBank followed by topology analysis of the resulting phylogenetic tree. The data indicated that the prevalent PCV2 isolates in the northeastern China had close relationship, although various genotypes of PCV2 existed. In addition, by gene recombination and transfection techniques, the PCV2 infectious clone was achieved and was able to rescue virus in vitro determined by indirect immunofluorescence assay and PCR. The obtained biological materials may be used for biological characterization of PCV2.

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

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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.

Plasmid borne Carbapenem-Hydrolyzing Class D β-Lactamases (CHDLs) and AdeABC efflux pump conferring carbapenem-tigecycline resistance among Acinetobacter baumannii isolates harboring TnAbaRs.

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Savari, Mohammad; Ekrami, Alireza; Shoja, Saeed; Bahador, Abbas

2017-03-01

Here we studied the prevalence and mechanisms of simultaneous resistance to carbapenem and tigecycline and accumulation of resistance determinants reservoirs in genome of Acinetobacter baumannii (A. baumannii) clinical isolates. Susceptibility of the isolates were measured to 18 antimicrobial agents. Genetic diversity of the microbial population was determined using the International Clonal lineage typing (IC typing), multiple locus VNTR analysis (MLVA) and plasmid profiling methods. To detect the AbaRs, Carbapenem-Hydrolyzing Class D β-Lactamases (CHDLs) genes, AdeABC efflux pump genes and resistance determinants, PCR was used. Filter mating experiments were used to prove that if carbapenem resistance genes are located on conjugative plasmids or not. Among the A. baumannii clinical isolates, 40.8% were carbapenem-tigecycline resistant and in this population, 46.9% were belonging to IC I, IC II or IC III and 53.1% were IC variants. These isolates had fallen in 40 MLVA types and were harboring plasmids in multiple numbers and sizes. In this study, bla OXA-23-like was the most prevalent CHDL and conjugation analysis proved that the carbapenem resistance genes are located on conjugative plasmids. All efflux pump genes, except for adeC, were detected in all carbapenem-tigecycline resistant A. baumannii (CTRAb) isolates. Resistance determinants were distributed in both TnAbaRs and R plasmids with a shift toward the R plasmids. Emerging of carbapenem resistant A. baumannii (CRAB) with simultaneous resistance to the last line therapy including tigecycline represent emerging of extensively drug resistance (XDR) and pandrug resistance (PDR) phenotypes that would be a great threat to our public health system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-drug resistant Acinetobacter infections in critically injured Canadian forces soldiers

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Brisebois Ronald

2007-08-01

Full Text Available Abstract Background Military members, injured in Afghanistan or Iraq, have returned home with multi-drug resistant Acinetobacter baumannii infections. The source of these infections is unknown. Methods Retrospective study of all Canadian soldiers who were injured in Afghanistan and who required mechanical ventilation from January 1 2006 to September 1 2006. Patients who developed A. baumannii ventilator associated pneumonia (VAP were identified. All A. baumannii isolates were retrieved for study patients and compared with A. baumannii isolates from environmental sources from the Kandahar military hospital using pulsed-field gel electrophoresis (PFGE. Results During the study period, six Canadian Forces (CF soldiers were injured in Afghanistan, required mechanical ventilation and were repatriated to Canadian hospitals. Four of these patients developed A. baumannii VAP. A. baumannii was also isolated from one environmental source in Kandahar – a ventilator air intake filter. Patient isolates were genetically indistinguishable from each other and from the isolates cultured from the ventilator filter. These isolates were resistant to numerous classes of antimicrobials including the carbapenems. Conclusion These results suggest that the source of A. baumannii infection for these four patients was an environmental source in the military field hospital in Kandahar. A causal linkage, however, was not established with the ventilator. This study suggests that infection control efforts and further research should be focused on the military field hospital environment to prevent further multi-drug resistant A. baumannii infections in injured soldiers.

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

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

2013-12-01

MALDI-TOF MS is currently becoming the method of choice for rapid identification of bacterial species in routine diagnostics. Yet, this method suffers from the inability to differentiate reliably between some closely related bacterial species including those of the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex, namely A. baumannii and Acinetobacter nosocomialis. In the present study, we evaluated a protocol which was different from that used in the Bruker Daltonics identification system (MALDI BioTyper) to improve species identification using a taxonomically precisely defined set of 105 strains representing the four validly named species of the ACB complex. The novel protocol is based on the change in matrix composition from alpha-cyano-4-hydroxycinnamic acid (saturated solution in water:acetonitrile:trifluoroacetic acid, 47.5:50:2.5, v/v) to ferulic acid (12.5mgml(-1) solution in water:acetonitrile:formic acid 50:33:17, v/v), while the other steps of sample processing remain unchanged. Compared to the standard protocol, the novel one extended the range of detected compounds towards higher molecular weight, produced signals with better mass resolution, and allowed the detection of species-specific signals. As a result, differentiation of A. nosocomialis and A. baumannii strains by cluster analysis was improved and 13 A. nosocomialis strains, assigned erroneously or ambiguously by using the standard protocol, were correctly identified. Copyright © 2013 Elsevier GmbH. All rights reserved.

Insights into the extremotolerance of Acinetobacter radioresistens 50v1, a gram-negative bacterium isolated from the Mars Odyssey spacecraft.

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McCoy, K B; Derecho, I; Wong, T; Tran, H M; Huynh, T D; La Duc, M T; Venkateswaran, K; Mogul, R

2012-09-01

The microbiology of the spacecraft assembly process is of paramount importance to planetary exploration, as the biological contamination that can result from remote-enabled spacecraft carries the potential to impact both life-detection experiments and extraterrestrial evolution. Accordingly, insights into the mechanisms and range of extremotolerance of Acinetobacter radioresistens 50v1, a Gram-negative bacterium isolated from the surface of the preflight Mars Odyssey orbiter, were gained by using a combination of microbiological, enzymatic, and proteomic methods. In summary, A. radioresistens 50v1 displayed a remarkable range of survival against hydrogen peroxide and the sequential exposures of desiccation, vapor and plasma phase hydrogen peroxide, and ultraviolet irradiation. The survival is among the highest reported for non-spore-forming and Gram-negative bacteria and is based upon contributions from the enzyme-based degradation of H(2)O(2) (catalase and alkyl hydroperoxide reductase), energy management (ATP synthase and alcohol dehydrogenase), and modulation of the membrane composition. Together, the biochemical and survival features of A. radioresistens 50v1 support a potential persistence on Mars (given an unintended or planned surface landing of the Mars Odyssey orbiter), which in turn may compromise the scientific integrity of future life-detection missions.

Antibacterial activity of a newly developed peptide-modified lysin against Acinetobacter baumannii and Pseudomonas aeruginosa

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Hang eYang

2015-12-01

Full Text Available The global emergence of multidrug-resistant (MDR bacteria is a growing threat to public health worldwide. Natural bacteriophage lysins are promising alternatives in the treatment of infections caused by Gram-positive pathogens, but not Gram-negative ones, like Acinetobacter baumannii and Pseudomonas aeruginosa, due to the barriers posed by their outer membranes. Recently, modifying a natural lysin with an antimicrobial peptide was found able to break the barriers, and to kill Gram-negative pathogens. Herein, a new peptide-modified lysin (PlyA was constructed by fusing the cecropin A peptide residues 1–8 (KWKLFKKI with the OBPgp279 lysin and its antibacterial activity was studied. PlyA showed good and broad antibacterial activities against logarithmic phase A. baumannii and P. aeruginosa, but much reduced activities against the cells in stationary phase. Addition of outer membrane permeabilizers (EDTA and citric acid could enhance the antibacterial activity of PlyA against stationary phase cells. Finally, no antibacterial activity of PlyA could be observed in some bio-matrices, such as culture media, milk, and sera. In conclusion, we reported here a novel peptide-modified lysin with significant antibacterial activity against both logarithmic (without OMPs and stationary phase (with OMPs A. baumannii and P. aeruginosa cells in buffer, but further optimization is needed to achieve broad activity in diverse bio-matrices.

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

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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.

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

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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.

Stereochemical insignificance discovered in Acinetobacter baumannii quorum sensing.

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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.

Evaluation of antibacterial effect of Myrtus communis against Acinetobacter baumannii clinical strains

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Venous Akhavan

2016-09-01

Full Text Available Because of inappropriate use of antibiotics and prevalence of resistant bacteria, there is urgent need for antibacterial drugs that have fewer side effects than antibiotics. Myrtus communis is a medicinal plant which had many uses in traditional medicine. In this study, ethanol leave extract of this plant is tested on Acinetobacter baumannii. In the case of antimicrobial evaluation of plants, one of the effecting factors on effectiveness of the microbial inhibition is extraction techniques. In the presents study, the antibacterial activity of the Ethanol, Methanol, and Ethyl acetate extracts of M. communis plant was evaluated at seven different concentrations by broth microdilution method. The results of this study showed that the antimicrobial effect of M. communis extract is concentration dependent. Different extracts were obtained by the maceration method. Extracts of the plant exhibited antibacterial activity at varied levels against A. baumannii. Obtained results from our antibacterial experiments showed that all extracts have anti-bacterial activity against tested bacterial isolates According to the results, the ethyl acetate extracted fraction showed the highest level of activity at a MIC 400 mg/ml for A. baumannii. The results of this study indicate that, different extracts had growth inhibitory effect on A. baumannii. Therefore this plant has the potential to be evaluated as an alternative or adjunct to antibiotics to treat Acinetobacter infections.

Evolution of a Pathogen: A Comparative Genomics Analysis Identifies a Genetic Pathway to Pathogenesis in Acinetobacter

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Sahl, Jason W.; Gillece, John D.; Schupp, James M.; Waddell, Victor G.; Driebe, Elizabeth M.; Engelthaler, David M.; Keim, Paul

2013-01-01

Acinetobacter baumannii is an emergent and global nosocomial pathogen. In addition to A. baumannii, other Acinetobacter species, especially those in the Acinetobacter calcoaceticus-baumannii (Acb) complex, have also been associated with serious human infection. Although mechanisms of attachment, persistence on abiotic surfaces, and pathogenesis in A. baumannii have been identified, the genetic mechanisms that explain the emergence of A. baumannii as the most widespread and virulent Acinetobacter species are not fully understood. Recent whole genome sequencing has provided insight into the phylogenetic structure of the genus Acinetobacter. However, a global comparison of genomic features between Acinetobacter spp. has not been described in the literature. In this study, 136 Acinetobacter genomes, including 67 sequenced in this study, were compared to identify the acquisition and loss of genes in the expansion of the Acinetobacter genus. A whole genome phylogeny confirmed that A. baumannii is a monophyletic clade and that the larger Acb complex is also a well-supported monophyletic group. The whole genome phylogeny provided the framework for a global genomic comparison based on a blast score ratio (BSR) analysis. The BSR analysis demonstrated that specific genes have been both lost and acquired in the evolution of A. baumannii. In addition, several genes associated with A. baumannii pathogenesis were found to be more conserved in the Acb complex, and especially in A. baumannii, than in other Acinetobacter genomes; until recently, a global analysis of the distribution and conservation of virulence factors across the genus was not possible. The results demonstrate that the acquisition of specific virulence factors has likely contributed to the widespread persistence and virulence of A. baumannii. The identification of novel features associated with transcriptional regulation and acquired by clades in the Acb complex presents targets for better understanding the

Genomic and proteomic evidences unravel the UV-resistome of the poly-extremophile Acinetobacter sp. Ver3.

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Kurth, Daniel; Belfiore, Carolina; Gorriti, Marta F; Cortez, Néstor; Farias, María E; Albarracín, Virginia H

2015-01-01

Ultraviolet radiation can damage biomolecules, with detrimental or even lethal effects for life. Even though lower wavelengths are filtered by the ozone layer, a significant amount of harmful UV-B and UV-A radiation reach Earth's surface, particularly in high altitude environments. high-altitude Andean lakes (HAALs) are a group of disperse shallow lakes and salterns, located at the Dry Central Andes region in South America at altitudes above 3,000 m. As it is considered one of the highest UV-exposed environments, HAAL microbes constitute model systems to study UV-resistance mechanisms in environmental bacteria at various complexity levels. Herein, we present the genome sequence of Acinetobacter sp. Ver3, a gammaproteobacterium isolated from Lake Verde (4,400 m), together with further experimental evidence supporting the phenomenological observations regarding this bacterium ability to cope with increased UV-induced DNA damage. Comparison with the genomes of other Acinetobacter strains highlighted a number of unique genes, such as a novel cryptochrome. Proteomic profiling of UV-exposed cells identified up-regulated proteins such as a specific cytoplasmic catalase, a putative regulator, and proteins associated to amino acid and protein synthesis. Down-regulated proteins were related to several energy-generating pathways such as glycolysis, beta-oxidation of fatty acids, and electronic respiratory chain. To the best of our knowledge, this is the first report on a genome from a polyextremophilic Acinetobacter strain. From the genomic and proteomic data, an "UV-resistome" was defined, encompassing the genes that would support the outstanding UV-resistance of this strain.

Genomic and proteomic evidences unravel the UV-resistome of the poly-extremophile Acinetobacter sp. Ver3

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Daniel eKurth

2015-04-01

Full Text Available Ultraviolet radiation can damage biomolecules, with detrimental or even lethal effects for life. Even though lower wavelengths are filtered by the ozone layer, a significant amount of harmful UV-B and UV-A radiation reach Earth’s surface, particularly in high altitude environments. High-Altitude Andean Lakes (HAAL are a group of disperse shallow lakes and salterns, located at the Dry Central Andes region in South America at altitudes above 3,000 m. As it is considered one of the highest UV-exposed environments, HAAL microbes constitute model systems to study UV-resistance mechanisms in environmental bacteria at various complexity levels. Herein, we present the genome sequence of Acinetobacter sp. Ver3, a gammaproteobacterium isolated from Lake Verde (4,400 m, together with further experimental evidence supporting the phenomenological observations regarding this bacterium ability to cope with increased UV-induced DNA damage. Comparison with the genomes of other Acinetobacter strains highlighted a number of unique genes, such as a novel cryptochrome. Proteomic profiling of UV-exposed cells identified up-regulated proteins such as a specific cytoplasmic catalase, a putative regulator, and proteins associated to amino acid and protein synthesis. Down-regulated proteins were related to several energy-generating pathways such as glycolysis, beta-oxidation of fatty acids and electronic respiratory chain. To the best of our knowledge, this is the first report on a genome from a polyextremophilic Acinetobacter strain. From the genomic and proteomic data, an UV-resistome was defined, encompassing the genes that would support the outstanding UV-resistance of this strain.

Genome sequencing and annotation of Acinetobacter gerneri strain MTCC 9824T

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Nitin Kumar Singh

2014-12-01

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

Acinetobacter baumannii in Southern Croatia: clonal lineages, biofilm formation, and resistance patterns.

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Kaliterna, Vanja; Kaliterna, Mariano; Hrenović, Jasna; Barišić, Zvonimir; Tonkić, Marija; Goic-Barisic, Ivana

2015-01-01

Acinetobacter baumannii is one of the most prevalent causes of severe hospital-acquired infections and is responsible for the dramatic increase in carbapenem resistance in Croatia in the last 5 years. Such data have encouraged multicenter research focused on the organism's ability to form biofilm, susceptibility to antibiotics, and particular genotype lineage. Biofilm formation in 109 unrelated clinical isolates of A. baumannii recovered in six cities of Southern Croatia was investigated. Genotyping was performed by pulsed-field gel electrophoresis and antibiotic profile was tested by applying the disc diffusion method and confirmed by determining the minimum inhibitory concentrations. The ability to form biofilm in vitro was determined from overnight cultures of the collected isolates on microtiter plates, after staining with crystal violet, and quantified at 570 nm after solubilization with ethanol. The statistical relevance was calculated in an appropriate program with level of statistical confidence. There was no significant difference in biofilm formation due to the genotype lineage. Isolates collected from intensive care units (ICUs) and isolated from respiratory samples were more likely to create a biofilm compared with isolates from other departments and other samples. There was a significant difference in the ability to produce biofilm in relation to antibiotic resistance pattern. A large proportion of A. baumannii isolates that were resistant to ampicillin/sulbactam, carbapenems, and amikacin were found to be biofilm-negative. In contrast, isolates susceptible and intermediately susceptible to ampicillin/sulbactam, carbapenems, and amikacin were biofilm producers. Clinical isolates of A. baumannii from respiratory samples in ICUs with a particular susceptibility pattern are more prone to form biofilm.

Acinetobacter phage genome is similar to Sphinx 2.36, the circular DNA copurified with TSE infected particles.

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Longkumer, Toshisangba; Kamireddy, Swetha; Muthyala, Venkateswar Reddy; Akbarpasha, Shaikh; Pitchika, Gopi Krishna; Kodetham, Gopinath; Ayaluru, Murali; Siddavattam, Dayananda

2013-01-01

While analyzing plasmids of Acinetobacter sp. DS002 we have detected a circular DNA molecule pTS236, which upon further investigation is identified as the genome of a phage. The phage genome has shown sequence similarity to the recently discovered Sphinx 2.36 DNA sequence co-purified with the Transmissible Spongiform Encephalopathy (TSE) particles isolated from infected brain samples collected from diverse geographical regions. As in Sphinx 2.36, the phage genome also codes for three proteins. One of them codes for RepA and is shown to be involved in replication of pTS236 through rolling circle (RC) mode. The other two translationally coupled ORFs, orf106 and orf96, code for coat proteins of the phage. Although an orf96 homologue was not previously reported in Sphinx 2.36, a closer examination of DNA sequence of Sphinx 2.36 revealed its presence downstream of orf106 homologue. TEM images and infection assays revealed existence of phage AbDs1 in Acinetobacter sp. DS002.

Molecular characterization of carbapenem-resistant Acinetobacter ...

African Journals Online (AJOL)

Purpose: To survey the molecular characteristics of imipenem-resistant Acinetobacter baumannii obtained from pediatric burns patients in a teaching hospital in Tehran, Iran. Methods: Over a 10-month period, 73 non-duplicate A. baumannii strains were collected from pediatric burns patients admitted to Motahari Burn and ...

Nosocomial imipenem-resistant Acinetobacter baumannii infections ...

African Journals Online (AJOL)

Imipenem-resistant Acinetobacter baumannii (A. baumannii) (IRAB) has emerged as a challenging nosocomial pathogen particularly in intensive care units (ICUs). Studying the risk factors associated with IRAB infection is of paramount importance for appropriate control of IRAB spread. The aim of this study was to assess ...

Wide Distribution of Carbapenem Resistant Acinetobacter baumannii in Burns Patients in Iran

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zahra eFarshadzadeh

2015-10-01

Full Text Available Antimicrobial resistance in carbapenem non-susceptible Acinetobacter baumannii (CNSAb is a major public health concern globally. This study determined the antibiotic resistance and molecular epidemiology of CNSAb isolates from a referral burn center in Tehran, Iran.Sixty-nine CNSAb isolates were tested for susceptibility to antimicrobial agents using the E-test methodology. Multiple locus variable number tandem repeat analysis (MLVA, Multilocus sequence typing and multiplex PCR were performed. PCR assays tested for ambler classes A, B, and D β-lactamases. Detection of ISAba1, characterization of integrons, and biofilm formation were investigated.Fifty-three (77% isolates revealed XDR phenotypes. High prevalence of blaOXA-23-like (88% and blaPER-1 (54% were detected. ISAba1 was detected upstream of blaADC, blaOXA-23-like and blaOXA51-like genes in, 97, 42 and 26% of isolates, respectively. Thirty-one (45% isolates were assigned to International Clone (IC variants. MLVA identified 56 distinct types with 6 clusters and 53 singleton genotypes. Forty previously known MLST sequence types forming 5 clonal complexes were identified. The Class 1 integron (class 1 integrons gene was identified in 84% of the isolates. The most prevalent (33% cassette combination was aacA4-catB8-aadA1. The IC variants were predominant in the A. baumannii lineage with the ability to form strong biofilms.The XDR-CNSAb from burned patients

Ecology and resistance of Moraxella-Acinetobacter

International Nuclear Information System (INIS)

Gulistani, A.W.

1977-01-01

The diverse microenvironments of foods, changing with processing and preservation, might provide conditions that would enhance the growth of microorganisms which are the principal cause of spoilage, off-odor and unpleasant flavor in foods. Radiation is a potential process which may provide a product with far superior microbial quality for food preservation, by reduction of microbial population; elimination of food-borne pathogens; extension of shelf-life; and reduction of spoilage. The aim of irradiation at low dose level is to eliminate certain microorganisms, especially spoilage types and those of public health significance. But, the radurization dose allows the outgrowth of radioresistant bacteria. Certain strains of Moraxella-Acinetobacter (M-A) groups have been recognized as radioresistant bacteria (Welch and Maxcy, 1975), which may have gone unnoticed by food microbiologists, since these bacteria have not been associated with problems and are present in relatively small numbers. However, irrradiation with radurization doses reduces the number of organisms and brings the M-A group into prominence, which may cause problems in irradiated foods. When M-A isolate No. 4 was grown in PCB and TSB media at 32 0 C and on PCA at ambient temperature and ambient RH, as well as when its resistance was observed in a film of various soiling materials on stainless steel surfaces at ambient temperature and room RH, it was concluded that these bacteria were resistant under various conditions for long periods of time. Other tests in which M-A isolates were observed were salt tolerance, various pH levels, quats, chlorine, antibiotic sensitivity, effects of dyes and hydrogen peroxide

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

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Ebringer, Alan; Rashid, Taha; Wilson, Clyde

2012-06-01

Multiple sclerosis (MS) is an autoimmune neurological disorder. The role of 'Acinetobacter' has been examined using the method of Karl Popper and involves nine "Popper sequences". (1) The frequency of MS increases with latitudes in the Northern Hemisphere, and the reverse is found in the Southern Hemisphere. (2) Sinusitis is found frequently at colder latitudes. (3) Sinusitis occurs frequently in patients with MS. (4) Specific sequences of bovine myelin when injected into experimental animals will produce a neurological disorder resembling MS which is called "experimental allergic encephalomyelitis". (5) Computer analysis of myelin shows molecular mimicry with sequences found in Acinetobacter. (6) Antibodies to Acinetobacter bacteria are found in MS patients. (7) Acinetobacter bacteria are located on human skin and in the nasal sinuses. (8) IgA antibodies are preferentially elevated in the sera of MS patients, thereby suggesting the trigger microbe is acting across a mucosal surface probably located in the nasal sinuses. (9) Only Acinetobacter bacteria and no other microbes evoke statistically significant titres of antibodies in MS patients. These nine Popper sequences suggest that MS is most probably caused by infections with Acinetobacter bacteria in the nasal sinuses, and this could have therapeutic implications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genome sequencing and annotation of Acinetobacter gyllenbergii strain MTCC 11365T

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Nitin Kumar Singh

2014-12-01

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

Coexistence of blaOXA-23 with armA in quinolone-resistant Acinetobacter baumannii from a Chinese university hospital.

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Shen, Min; Luan, Guangxin; Wang, Yanhong; Chang, Yaowen; Zhang, Chi; Yang, Jingni; Deng, Shanshan; Ling, Baodong; Jia, Xu

2016-03-01

A total of 101 Acinetobacter baumannii isolates were collected to determine the mechanisms of quinolone resistance and investigate the occurrence of carbapenem and high-level aminoglycoside resistance genes among quinolone-resistant strains. Among 77 quinolone-resistant A. baumannii harbored mutations of gyrA and parC, 41 isolates, which belonged to European clone II, had resistance to aminoglycosides and carbapenems due to the expression of armA and acquisition of blaOXA-23. Most of sequence type belonged to clonal complex 92. These results suggested hospital dissemination of multidrug-resistant A. baumannii carrying blaOXA-23, armA, and mutations of quinolone resistance-determining regions in western China. Copyright © 2016 Elsevier Inc. All rights reserved.

Isolation, identification and diesel-oil biodegradation capacities of indigenous hydrocarbon-degrading strains of Cellulosimicrobium cellulans and Acinetobacter baumannii from tarball at Terengganu beach, Malaysia.

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Nkem, Bruno Martins; Halimoon, Normala; Yusoff, Fatimah Md; Johari, Wan Lufti Wan; Zakaria, Mohamad Pauzi; Medipally, Srikanth Reddy; Kannan, Narayanan

2016-06-15

In this study, we isolated two indigenous hydrocarbon-degrading bacteria from tarball found in Rhu Sepuluh beach, Terengganu, Malaysia. These bacteria were identified based on their physiological characteristic and 16S rRNA gene sequence analysis, and they showed 99% similarity with Cellulosimicrobium cellulans DSM 43879 and Acinetobacter baumannii ATCC 19606 respectively. Their hydrocarbon-degrading capabilities were tested using diesel-oil as sole carbon source. Results analysed using GC-MS, showed diesel-oil alkanes were degraded an average 64.4% by C. cellulans and 58.1% by A. baumannii with medium optical density reaching 0.967 (C. cellulans) and 1.515 (A. baumannii) in minimal salt media at 32°C for 10days. Individual diesel-oil alkanes were degraded between 10%-95.4% by C. cellulans and 0.2%-95.9% by A. baumannii. Both strains utilized diesel-oil for growth. The study suggests both strains are part of indigenous hydrocarbon-degrading bacteria in tarball with potential for bioremediation of oil-polluted marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioinformatic analysis of phage AB3, a phiKMV-like virus infecting Acinetobacter baumannii.

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Zhang, J; Liu, X; Li, X-J

2015-01-16

The phages of Acinetobacter baumannii has drawn increasing attention because of the multi-drug resistance of A. baumanni. The aim of this study was to sequence Acinetobacter baumannii phage AB3 and conduct bioinformatic analysis to lay a foundation for genome remodeling and phage therapy. We isolated and sequenced A. baumannii phage AB3 and attempted to annotate and analyze its genome. The results showed that the genome is a double-stranded DNA with a total length of 31,185 base pairs (bp) and 97 open reading frames greater than 100 bp. The genome includes 28 predicted genes, of which 24 are homologous to phage AB1. The entire coding sequence is located on the negative strand, representing 90.8% of the total length. The G+C mol% was 39.18%, without areas of high G+C content over 200 bp in length. No GC island, tRNA gene, or repeated sequence was identified. Gene lengths were 120-3099 bp, with an average of 1011 bp. Six genes were found to be greater than 2000 bp in length. Genomic alignment and phylogenetic analysis of the RNA polymerase gene showed that similar to phage AB1, phage AB3 is a phiKMV-like virus in the T7 phage family.

Molecular mechanisms associated with nosocomial carbapenem-resistant Acinetobacter baumannii in Mexico.

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Alcántar-Curiel, María Dolores; García-Torres, Luis Francisco; González-Chávez, María Inés; Morfín-Otero, Rayo; Gayosso-Vázquez, Catalina; Jarillo-Quijada, Ma Dolores; Fernández-Vázquez, José Luis; Giono-Cerezo, Silvia; Rodríguez-Noriega, Eduardo; Santos-Preciado, José Ignacio

2014-10-01

Acinetobacter baumannii is an emerging pathogen worldwide that is most commonly associated with nosocomial infections and multi-drug resistance. In the present study we determined the mechanisms of carbapenem resistance and clonal diversity of A. baumannii nosocomial isolates in Hospital Civil de Guadalajara, Mexico. A total of 303 clinical isolates of A. baumannii identified during a period expanding from 2004-2011 were analyzed for carbapenem resistance using several microbiological and molecular methods. Clonal relatedness of these isolates was determined using pulsed-field gel electrophoresis. Of the 303 isolates, 84% were resistant to meropenem, 71.3% to imipenem and 78.3% the resistant isolates were positive for metallo-β-lactamases as determined by the phenotypic assay. In addition, 49.6% of carbapenem-intermediate or -resistant isolates carried the blaOXA-72 gene and 1.2% carried the blaVIM-1 gene. Efflux pump phenotype was responsible for reduced susceptibility to meropenem in 14.5% and to imipenem in 31.6% of the resistant isolates, respectively in the presence of the efflux pump inhibitor, carbonyl cyanide 3-chlorophenylhydrazone. Strains representing different carbapenem-resistant patterns exhibited reduced expression of 22, 29, 33, and 43 kDa OMPs. Among the bacterial collection studied, 48 different clones were identified, two of which were predominant and persistently transmitted. Carbapenemase production in combination with efflux pump expression, reduction in OMPs expression and the cross-transmission of clones appear to be major contributors to the high frequency of carbapenem-resistance observed in A. baumannii. To our knowledge, this is the first study to define the molecular mechanisms associated with carbapenem-resistance in A. baumannii in Mexico. Copyright © 2014 IMSS. Published by Elsevier Inc. All rights reserved.

Spread of carbapenem-resistant Acinetobacter baumannii global clone 2 in Asia and AbaR-type resistance islands.

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Kim, Dae Hun; Choi, Ji-Young; Kim, Hae Won; Kim, So Hyun; Chung, Doo Ryeon; Peck, Kyong Ran; Thamlikitkul, Visanu; So, Thomas Man-Kit; Yasin, Rohani M D; Hsueh, Po-Ren; Carlos, Celia C; Hsu, Li Yang; Buntaran, Latre; Lalitha, M K; Song, Jae-Hoon; Ko, Kwan Soo

2013-11-01

In this surveillance study, we identified the genotypes, carbapenem resistance determinants, and structural variations of AbaR-type resistance islands among carbapenem-resistant Acinetobacter baumannii (CRAB) isolates from nine Asian locales. Clonal complex 92 (CC92), corresponding to global clone 2 (GC2), was the most prevalent in most Asian locales (83/108 isolates; 76.9%). CC108, or GC1, was a predominant clone in India. OXA-23 oxacillinase was detected in CRAB isolates from most Asian locales except Taiwan. blaOXA-24 was found in CRAB isolates from Taiwan. AbaR4-type resistance islands, which were divided into six subtypes, were identified in most CRAB isolates investigated. Five isolates from India, Malaysia, Singapore, and Hong Kong contained AbaR3-type resistance islands. Of these, three isolates harbored both AbaR3- and AbaR4-type resistance islands simultaneously. In this study, GC2 was revealed as a prevalent clone in most Asian locales, with the AbaR4-type resistance island predominant, with diverse variants. The significance of this study lies in identifying the spread of global clones of carbapenem-resistant A. baumannii in Asia.

Improved production of isomaltulose by a newly isolated mutant of Serratia sp. cells immobilized in calcium alginate.

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Kim, Yonghwan; Koo, Bong-Seong; Lee, Hyeon-Cheol; Yoon, Youngdae

2015-03-01

Isomaltulose, also known as palatinose, is produced by sucrose isomerase and has been highlighted as a sugar substitute due to a number of advantageous properties. For the massive production of isomaltulose, high resistance to sucrose and stability of sucrose isomerase as well as sucrose conversion yields would be critical factors. We describe a series of screening procedures to isolate the mutant strain of Serratia sp. possessing enhanced isomaltulose production with improved stability. The new Serratia sp. isolated from a series of screening procedures allowed us to produce isomaltulose from 60% sucrose solution, with over 90% conversion yield. Moreover, when this strain was immobilized in calcium alginate beads and placed in a medium containing 60% sucrose, it showed over 70% sucrose conversion yields for 30 cycles of repeated-batch reactions. Thus, improved conversion activity and stability of the newly isolated Serratia sp. strain in the present study would be highly valuable for industries related to isomaltulose production.

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...

Simultaneous Microcystis Algicidal and Microcystin Degrading Capability by a Single Acinetobacter Bacterial Strain.

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Li, Hong; Ai, Hainan; Kang, Li; Sun, Xingfu; He, Qiang

2016-11-01

Measures for removal of toxic harmful algal blooms often cause lysis of algal cells and release of microcystins (MCs). In this study, Acinetobacter sp. CMDB-2 that exhibits distinct algal lysing activity and MCs degradation capability was isolated. The physiological response and morphological characteristics of toxin-producing Microcystis aeruginosa, the dynamics of intra- and extracellular MC-LR concentration were studied in an algal/bacterial cocultured system. The results demonstrated that Acinetobacter sp. CMDB-2 caused thorough decomposition of algal cells and impairment of photosynthesis within 24 h. Enhanced algal lysis and MC-LR release appeared with increasing bacterial density from 1 × 10 3 to 1 × 10 7 cells/mL; however, the MC-LR was reduced by nearly 94% within 14 h irrespective of bacterial density. Measurement of extracellular and intracellular MC-LR revealed that the toxin was decreased by 92% in bacterial cell incubated systems relative to control and bacterial cell-free filtrate systems. The results confirmed that the bacterial metabolite caused 92% lysis of Microcystis aeruginosa cells, whereas the bacterial cells were responsible for approximately 91% reduction of MC-LR. The joint efforts of the bacterium and its metabolite accomplished the sustainable removal of algae and MC-LR. This is the first report of a single bacterial strain that achieves these dual actions.

Enantioselective hydrolysis of racemic styrene oxide and its substituted derivatives using newly-isolated Sphingopyxis sp. exhibiting a novel epoxide hydrolase activity.

Science.gov (United States)

Woo, Jung-Hee; Lee, Eun Yeol

2014-02-01

(S)-Styrene oxide, (S)-2-chlorostyrene oxide (CSO), (S)-3-CSO and (S)-4-CSO with 99.9 %ee were obtained with a yield of 20.6, 39.3, 28.7 and 26.8 % from 4 mM corresponding racemic substrates using 10 mg cells of a newly-isolated Sphingopyxis sp. at pH 8.0 and 25 °C in 1 ml 100 mM Tris/HCl buffer after 420, 100, 120 and 55 min, respectively. For racemic 2CSO, well-known for one of the racemates that is difficult to obtained in enantiomerically pure form, (S)-2-CSO with 99.9 %ee, 39.3 % yield (theoretical yield 50 %) and enantiomeric ratio of 42.1 was obtained. The newly-isolated strain can thus be used as whole-cell biocatalyst in the production of various (S)-CSO with a chlorine group at different positions.

[Nosocomial infection/colonization of the respiratory tract caused by Acinetobacter baumannii in an Internal Medicine ward].

Science.gov (United States)

Salas Coronas, J; Cabezas Fernández, T; Alvarez-Ossorio García de Soria, R; Rogado González, M C; Delgado Fernández, M; Díez García, F

2002-10-01

To present the epidemiology of the outbreak and the description of patients with infection or colonization of the respiratory tract caused by A. baumannii in an Internal Medicine ward. 20 consecutively patients hospitalized in the Internal Medicine ward were studied during 18 months with isolation of multiresistant A. baumanni in respiratory tract specimens with or without clinical signs of infection. Starting on an index case, that was a patient coming from other hospital with diagnosis of nosocomial Acinetobacter pneumonia, we detected 20 patients. The age of the patients ranged from 48 to 95 years, with a mean of 71.4 years. Eighty percent were males. The clinical features were similar: advanced age, with chronic diseases (35 percent diabetics, 45 percent with chronic lung diseases), and use of broad-spectrum antibiotics agents, fundamentally third generation cephalosporin (70 percent), clarithromycin (55 percent) and quinolones (30 percent). 75 percent of patients were in the same ward. Eight (40 percent) of the patients with chronic lung diseases were subjects with COPD, two with asthma and chronic glucocorticoids treatment, and one with a sleep apnea. In four cases the isolation was considered a colonization. The mean stay was 26.15 days, and the mortality 40 percent. The nosocomial infection caused by Acinetobacter baumannii is responsible of a high morbi-mortality between the patients hospitalized in an Internal Medicine ward, and produce an increase in length of stay. It is necessary a combination of control measures to prevent the transmission in the hospital and the outbreak of new multiresistant strains.

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

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Mortensen, Brittany L.; Skaar, Eric P.

2013-01-01

Summary 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 defense 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. PMID:22640368

Multidrug Resistant Acinetobacter Infection and Their Antimicrobial ...

African Journals Online (AJOL)

Background: Acinetobacter baumannii, a non-glucose fermenting Gram negative bacillus, has emerged in the last three decades as a major etiological agent of hospital-associated infections giving rise to significant morbidity and mortality particularly in immunocompromised patients. Multidrug resistant A. baumannii ...

Trend of extensively drug-resistant Acinetobacter baumannii and the remaining therapeutic options: a multicenter study in Tehran, Iran over a 3-year period.

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Jasemi, S; Douraghi, M; Adibhesami, H; Zeraati, H; Rahbar, M; Boroumand, M A; Aliramezani, A; Ghourchian, S; Mohammadzadeh, M

2016-12-01

Comprehensive data on drug-resistant patterns of Acinetobacter baumannii isolates in developing countries is limited. We conducted a multihospital study to assess the rate and trend of drug-resistant phenotypes in Ac. baumannii using standardized definitions and to determine the remaining therapeutic options against resistant phenotypes. The 401 nonduplicate isolates were collected from six hospitals which are geographically distributed across Tehran, Iran over a 3-year period. Following PCR of bla OXA -51-like gene, susceptibility testing was performed against nine antimicrobial agent categories. Three hundred and ninety (97%) isolates were resistant to least two carbapenems; carbapenem-resistant Ac. baumannii. The majority of isolates (366, 91·3%) were extensively drug resistant (XDR) and the rest of the isolates were classified as multidrug resistant (26, 6·8%) and susceptible (9, 2·2%). The rate of XDR-AB slightly decreased from 93·8% in 2011 to 89·8% in 2013. A considerable decrease in resistance to doxycycline, minocycline and tigecycline was demonstrated. The XDR-AB isolates showed susceptibility to gentamicin (10·4%), tobramycin (23%), ampicilin-sulbactam (30·1%), minocycline (32·8%), tigecycline (10·7%), doxycycline (21·6%), colistin (100%) and polymixin B (100%). We demonstrated the rising trend of resistance to all antibiotic categories except tetracyclines and folate pathway inhibitors. We found that the treatment options against XDR-AB are extremely limited and each treatment alternative including even old, but safe, antibiotics might be considered. The high frequency of drug-resistant phenotypes including carbapenem-resistant Acinetobacter baumannii, multidrug-resistant, and extensively resistant has been demonstrated in Ac. baumannii isolates tested here. As the antibiotic resistance pattern of isolates varies in different geographical regions, this study can provide comprehensive information about the antibiotic resistance profile of Ac

In vitro Evaluation of the Colistin-Carbapenem Combination in Clinical Isolates of A. baumannii Using the Checkerboard, Etest, and Time-Kill Curve Techniques.

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Soudeiha, Micheline A H; Dahdouh, Elias A; Azar, Eid; Sarkis, Dolla K; Daoud, Ziad

2017-01-01

The worldwide increase in the emergence of carbapenem resistant Acinetobacter baumannii (CRAB) calls for the investigation into alternative approaches for treatment. This study aims to evaluate colistin-carbapenem combinations against Acinetobacter spp., in order to potentially reduce the need for high concentrations of antibiotics in therapy. This study was conducted on 100 non-duplicate Acinetobacter isolates that were collected from different patients admitted at Saint George Hospital-University Medical Center in Beirut. The isolates were identified using API 20NE strips, which contain the necessary agents to cover a panel of biochemical tests, and confirmed by PCR amplification of bla OXA-51-like . Activities of colistin, meropenem and imipenem against Acinetobacter isolates were determined by ETEST and microdilution methods, and interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. In addition, PCR amplifications of the most common beta lactamases contributing to carbapenem resistance were performed. Tri locus PCR-typing was also performed to determine the international clonality of the isolates. Checkerboard, ETEST and time kill curves were then performed to determine the effect of the colistin-carbapenem combinations. The synergistic potential of the combination was then determined by calculating the Fractional Inhibitory Concentration Index (FICI), which is an index that indicates additivity, synergism, or antagonism between the antimicrobial agents. In this study, 84% of the isolates were resistant to meropenem, 78% to imipenem, and only one strain was resistant to colistin. 79% of the isolates harbored bla OXA-23-like and pertained to the International Clone II. An additive effect for the colistin-carbapenem combination was observed using all three methods. The combination of colistin-meropenem showed better effects as compared to colistin-imipenem ( p carbapenems could be a promising antimicrobial strategy in

The change of antibiotic resistance profiles over the years in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from intensive care units

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M. Cem Şirin

2015-09-01

Full Text Available Objective: The aim of this study was to determine the antibiotic resistance profiles of Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from patients in our hospital intensive care units (ICUs between the years 2011-2014 and to investigate the changes of these profiles over the years. Methods: Identification and antibiotic susceptibility testing of the strains were performed by automated system. Cefoperazone-sulbactam and tigecycline susceptibility was determined by disk diffusion method. Imipenem, meropenem and colistin resistance was confirmed by E-test method. Chi-square and Fisher's exact test were used to compare the antibiotic susceptibilities statistically. Results: The highest resistance rates were determined for imipenem (50.2%, meropenem (51.9% and piperacillin-tazobactam (64.0% in P. aeruginosa strains (n=722. The changes in the rates of antibiotic resistance were not statistically significant in P. aeruginosa strains between the years 2011 and 2014. The decrease in gentamicin, amikacin and trimethoprim-sulfamethoxazole resistance and the increase in cefoperazone-sulbactam and tigecycline resistance was found to be statistically significant in A. baumannii strains (n=1044 between the years 2011 and 2014. The increase in imipenem and meropenem resistance was found to be statistically significant between the years 2012 and 2013. Piperacillin-tazobactam, ceftazidime, cefepime, imipenem and meropenem resistances in A. baumannii strains were found to be over 95% in all the years. Colistin was found to be the most effective antimicrobial agent for both bacteria. Conclusion: The determination of considerably high antibiotic resistance rates in P. aeruginosa and A. baumannii strains isolated from our hospital ICUs has indicated that rational antibiotic use policies and more effective infection control programs should be applied along with monitoring the antibiotic susceptibility profiles constantly. J Clin Exp Invest 2015

Clinical and Epidemiological Significance of Carbapenem Resistance in Acinetobacter baumannii Infections.

Science.gov (United States)

Tal-Jasper, Ruthy; Katz, David E; Amrami, Nadav; Ravid, Dor; Avivi, Dori; Zaidenstein, Ronit; Lazarovitch, Tsilia; Dadon, Mor; Kaye, Keith S; Marchaim, Dror

2016-05-01

Carbapenems are considered the treatment of choice for Acinetobacter baumannii infections. Many facilities implement preventive measures toward only carbapenem-resistant A. baumannii (CRAB). However, the independent role of the carbapenem resistance determinant on patient outcomes remains controversial. In a 6-year analysis of adults with A. baumannii bloodstream infection (BSI), the outcomes of 149 CRAB isolates were compared to those of 91 patients with carbapenem-susceptible A. baumannii In bivariable analyses, CRAB BSIs were significantly associated with worse outcomes and with a delay in the initiation of appropriate antimicrobial therapy (DAAT). However, in multivariable analyses, carbapenem resistance status was no longer associated with poor outcomes, while DAAT remained an independent predictor. The epidemiological significance of A. baumannii should not be determined by its resistance to carbapenems. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Differential Role of the T6SS in Acinetobacter baumannii Virulence

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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

Differential Role of the T6SS in Acinetobacter baumannii Virulence.

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Guillermo D Repizo

Full Text Available Gram-negative bacteria, such as Acinetobacter baumannii, are an increasing burden in hospitals worldwide with an alarming spread of multi-drug resistant (MDR strains. Herein, we compared a type strain (ATCC17978, a non-clinical isolate (DSM30011 and MDR strains of A. baumannii implicated in hospital outbreaks (Ab242, Ab244 and Ab825, revealing distinct patterns of type VI secretion system (T6SS functionality. The T6SS genomic locus is present and was actively transcribed in all of the above strains. However, only the A. baumannii DSM30011 strain was capable of killing Escherichia coli in a T6SS-dependent manner, unlike the clinical isolates, which failed to display an active T6SS in vitro. In addition, DSM30011 was able to outcompete ATCC17978 as well as Pseudomonas aeruginosa and Klebsiella pneumoniae, bacterial pathogens relevant in mixed nosocomial infections. Finally, we found that the T6SS of DSM30011 is required for host colonization of the model organism Galleria mellonella suggesting that this system could play an important role in A. baumannii virulence in a strain-specific manner.

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

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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. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

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

DEFF Research Database (Denmark)

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

2014-01-01

nature of glycan biogenesis we investigated the composition, diversity, and properties of the Acinetobacter glycoproteome. Utilizing global and targeted mass spectrometry methods, we examined 15 strains and found extensive glycan diversity in the O-linked glycoproteome of Acinetobacter. Comparison......-linked glycosylation favors short (three to five residue) glycans with limited branching containing negatively charged sugars such as GlcNAc3NAcA4OAc or legionaminic/pseudaminic acid derivatives. These observations suggest that although highly diverse, the capsule/O-linked glycan biosynthetic pathways generate glycans...

Glucose availability enhances lipopolysaccharide production and immunogenicity in the opportunistic pathogen Acinetobacter baumannii.

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Rossi, Elio; Longo, Francesca; Barbagallo, Marialuisa; Peano, Clelia; Consolandi, Clarissa; Pietrelli, Alessandro; Jaillon, Sebastian; Garlanda, Cecilia; Landini, Paolo

2016-01-01

Acinetobacter baumannii can cause sepsis with high mortality rates. We investigated whether glucose sensing might play a role in A. baumannii pathogenesis. We carried out transcriptome analysis and extracellular polysaccharide determination in an A. baumannii clinical isolate grown on complex medium with or without glucose supplementation, and assessed its ability to induce production of inflammatory cytokines in human macrophages. Growth in glucose-supplemented medium strongly enhanced A. baumannii sugar anabolism, resulting in increasing lipopolysaccharide biosynthesis. In addition, glucose induced active shedding of lipopolysaccharide, in turn triggering a strong induction of inflammatory cytokines in human macrophages. Finally, hemolytic activity was strongly enhanced by growth in glucose-supplemented medium. We propose that sensing of exogenous glucose might trigger A. baumannii pathogenesis during sepsis.

Frequency and antibiotic resistance patterns of isolated bacteria from positive blood culture of hospitalized patients

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Azadeh Vahedi

2018-03-01

Conclusion: The most prevalent bacterial isolate among the blood cultures of patients was Pseudomonas. The patients more than 50 years were more susceptible to blood stream infections. The most bacteria were isolated from the internal medicine department of hospital. The antibiotic resistance was also increasing especially in Acinetobacter, Staphylococcus coagulase negative, Escherichia coil and Klebsiella

Isolation, molecular and biochemical characterization of oil degrading bacteria from contaminated soil at an oil refinery

International Nuclear Information System (INIS)

AL-Deeb, T.M.; Malkawi, H.I.

2009-01-01

Biodegradation using microorganisms is considered to be cost-effective and environmentally friendly treatment of oil-contaminated sites. Oil-biodegrading bacterial strains were isolated, identified and characterized from oil contaminated soil samples at oil refinery in Zarqa (Jordan). Thirty four bacterial isolates were grown on mineral salt media supplemented with crude oil, but 16 showed positive biodegradation of diesel. All the 34 bacterial isolates were characterized at the molecular and bio-chemical levels, and showed positive polymerase chain reaction (PCR) amplification product size of 1500 bp when 16s rDNA bacterial universal primers were used. Eighteen bacterial isolates showed positive PCR amplification product size of 150 bp specific for the genus Pseudomonas and 3 bacterial isolates showed positive amplification product size of 1500 bp specific for the genus Acinetobacter. Biochemical and physiological characterization performed on the 34 bacterial isolates revealed the presence of oil biodegrading bacterial genera and species of Pseudomonas Acidovorans, P. aeruginosa, P. vesicularis, Acinetobacter calcoaceticus, Ac. lowffii, Micro-ococcus luteus, M. varians, M. lylae, M. roseus, Alcaligenes denitrificians, Bacillus megaterium, Comamonas sp., Moralxella sp., Bordetella sp., P. putida, P. stutzeri and P. mallei. (au)

Clonal diversity and detection of carbapenem resistance encoding genes among multidrug-resistant Acinetobacter baumannii isolates recovered from patients and environment in two intensive care units in a Moroccan hospital

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Jean Uwingabiye

2017-09-01

Full Text Available Abstract Background Carbapenem-resistant Acinetobacter baumannii has recently been defined by the World Health Organization as a critical pathogen. The aim of this study was to compare clonal diversity and carbapenemase-encoding genes of A. baumannii isolates collected from colonized or infected patients and hospital environment in two intensive care units (ICUs in Morocco. Methods The patient and environmental sampling was carried out in the medical and surgical ICUs of Mohammed V Military teaching hospital from March to August 2015. All A. baumannii isolates recovered from clinical and environmental samples, were identified using routine microbiological techniques and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed using disc diffusion method. The carbapenemase-encoding genes were screened for by PCR. Clonal relatedness was analyzed by digestion of the DNA with low frequency restriction enzymes and pulsed field gel electrophoresis (PFGE and the multi locus sequence typing (MLST was performed on two selected isolates from two major pulsotypes. Results A total of 83 multidrug-resistant A. baumannii isolates were collected: 47 clinical isolates and 36 environmental isolates. All isolates were positive for the bla OXA51-like and bla OXA23-like genes. The coexistence of bla NDM-1 /bla OXA-23-like and bla OXA 24-like /bla OXA-23-like were detected in 27 (32.5% and 2 (2.4% of A. baumannii isolates, respectively. The environmental samples and the fecally-colonized patients were significantly identified (p < 0.05 as the most common sites of isolation of NDM-1-harboring isolates. PFGE grouped all isolates into 9 distinct clusters with two major groups (0007 and 0008 containing up to 59% of the isolates. The pulsotype 0008 corresponds to sequence type (ST 195 while pulsotype 0007 corresponds to ST 1089.The genetic similarity between the clinical and environmental isolates

Database for the ampC alleles in Acinetobacter baumannii.

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Nabil Karah

Full Text Available Acinetobacter baumannii is a troublesome opportunistic pathogen with a high capacity for clonal dissemination. We announce the establishment of a database for the ampC locus in A. baumannii, in which novel ampC alleles are differentiated based on the occurrence of ≥ 1 nucleotide change, regardless of whether it is silent or missense. The database is openly accessible at the pubmlst platform for A. baumannii (http://pubmlst.org/abaumannii/. Forty-eight distinctive alleles of the ampC locus have so far been identified and deposited in the database. Isolates from clonal complex 1 (CC1, according to the Pasteur multilocus sequence typing scheme, had a variety of the ampC locus alleles, including alleles 1, 3, 4, 5, 6, 7, 8, 13, 14, 17, and 18. On the other hand, isolates from CC2 had the ampC alleles 2, 3, 19, 20, 21, 22, 23, 24, 26, 27, 28, and 46. Allele 3 was characteristic for sequence types ST3 or ST32. The ampC alleles 10, 16, and 25 were characteristic for CC10, ST16, and CC25, respectively. Our study points out that novel gene databases, in which alleles are numbered based on differences in their nucleotide identities, should replace traditional records that use amino acid substitutions to define new alleles.

A five year study on the susceptibility of isolates from various parts of ...

African Journals Online (AJOL)

tests. The various isolates for the five-year period were Staphylococcus aureus 1000, Klebsiella pneumoniae 340, Proteus mirabilis 38 Escherichia coli 295, Pseudomonas aeroginosa 240, Alcaligenes faecalis 200, Enterobacter aerogenes 175, Acinetobacter baumannii 150, Proteus vulgaris 110, Providencia stuartii 101, ...

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

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Adrián Golic

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

Staring at the Cold Sun: Blue Light Regulation Is Distributed within the Genus Acinetobacter

Science.gov (United States)

Golic, Adrián; Vaneechoutte, Mario; Nemec, Alexandr; Viale, Alejandro M.; Actis, Luis A.; Mussi, María Alejandra

2013-01-01

We previously showed that the opportunistic nosocomial pathogen Acinetobacter baumannii is able to sense and respond to light via BlsA, a BLUF (Blue-Light-sensing Using FAD)-domain photoreceptor protein. Here, we extend our previous studies showing that light regulation is not restricted to A. baumannii, but rather widespread within the genus Acinetobacter. First, we found that blue light modulates motility and biofilm formation in many species of the genus, including members of the Acinetobacter calcoaceticus-A. baumannii complex. In many of these species blue light acts as a key factor guiding the decision between motility or sessility at 24°C, whereas in A. baumannii, light inhibits both motility and biofilm formation. We also show that light regulation of motility occurred not only at 24°C but also at 37°C in non-A. baumannii species, contrasting the situation of A. baumannii which only shows photoregulation at 24°C. Second, we show that Acinetobacter baylyi (strain ADP1) BLUF-photoreceptors can functionally replace in vivo the A. baumannii 17978 BlsA protein and that the pathways leading to biofilm formation are inversely regulated at 24°C between these two microorganisms. Finally, we found the presence of predicted genes coding BLUF-containing proteins in all Acinetobacter sequenced genomes, even though the copy number is variable among them. Phylogenetic analysis suggests a common origin for all BLUF domains present in members of this genus, and could distinguish well-differentiated clusters that group together BLUF homologs from different species, a situation particularly clear for members of the ACB complex. Despite a role played by these BLUF domain-containing proteins in the photoregulation observed in the members of the genus Acinetobacter is a likely scenario given our findings in A. baumannii and A. baylyi, further research will contribute to confirm this possibility. PMID:23358859

Identification of a new geographically widespread multiresistant Acinetobacter baumannii clone from European hospitals.

Science.gov (United States)

van Dessel, Helke; Dijkshoorn, Lenie; van der Reijden, Tanny; Bakker, Nancy; Paauw, Armand; van den Broek, Peterhans; Verhoef, Jan; Brisse, Sylvain

2004-03-01

The aim of the study was to investigate the genetic diversity of Acinetobacter baumannii clinical strains that had previously been allocated to three major groups based on automated ribotyping. Forty-seven isolates from European hospitals and one isolate from a South African hospital, geographically representative of the three ribogroups (ribogroups 1, 2 and 3 with 10, 23 and 15 isolates, respectively), were analysed using the highly discriminatory fingerprinting methods AFLP and pulsed-field gel electrophoresis (PFGE). Based on AFLP data, the isolates clustered into three main groups, each corresponding to one ribogroup. Inclusion of reference strains of the previously described clones I and II, responsible for outbreaks in northwestern European hospitals, showed that ribogroups 1 and 2 correspond to clones I and II, respectively, whereas ribogroup 3 apparently represents a new clone. This clone III was found in France, The Netherlands, Italy and Spain. Clones I and II were not limited to northwestern European countries, as they were also recovered from Spain, South Africa, Poland and Italy (clone I) and from Spain, Portugal, South Africa, France, Greece and Turkey (clone II). Combined AFLP and PFGE data showed intraclonal diversity and led to the distinction of 23 different genotypes. Three genotypes, two of them belonging to clone II and one to clone III, were found in different hospitals and may correspond to subsets of isolates with a more recent clonal relationship, which emphasizes the epidemic potential of these organisms.

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

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Amreeta Dhanoa

2015-01-01

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

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

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Junyan Qu

2016-01-01

Full Text Available This study aimed to analyze the clinical characteristics of patients and molecular mechanisms of the first outbreak mainly caused by sequence types (STs 208 multidrug resistant (MDR Acinetobacter baumannii in China. A total of 10 clinical samples were collected from 5 patients who were involved in the outbreak. Bacterial identification and antibiotic sensitivity tests were performed by the VITEK-2 COMPACT automated system. MICs of tigecycline for clinical isolates were determined using broth microdilution. The clonal relatedness of A. baumannii clinical isolates in our local settings was determinated by pulsed-field gel electrophoresis (PFGE and multilocus sequence typing (MLST. A total of 7 A. baumannii strains were isolated and all were MDR strains; two of them were carbapenem-nonsusceptible strains. blaOXA-23 was the only acquired carbapenemase gene in the isolates. The isolates belonged to a single clonal pulsotype determined by PFGE and two sequences types (STs determined by MLST. The isolates belonged to the globally disseminated clonal complex 92, among which ST195 and ST208 were the most common sequence types (71.43% and 28.57%. The outbreak was successfully controlled by stringent infection control measures, especially improving the hand hygiene compliance and enhancing antimicrobial stewardship. In conclusion, this is the first description of an outbreak caused mainly by A. baumannii of ST208 in China. Infection control measures should be strengthened when infection outbreaks in hospital.

CHROMagar COL-APSE: a selective bacterial culture medium for the isolation and differentiation of colistin-resistant Gram-negative pathogens

DEFF Research Database (Denmark)

Abdul Momin, Muhd Haziq F; Bean, David C; Hendriksen, Rene S.

2017-01-01

Purpose. A selective chromogenic culture medium for the laboratory isolation and differentiation of colistin resistant Acinetobacter, Pseudomonas, Stenotrophomonas and Enterobacteriaceae spp. (CHROMagar COL-APSE) was developed, evaluated and compared to an existing selective bacterial culture......-resistant non-fermentative bacteria (Acinetobacter, Pseudomonas and Stenotrophomonas). CHROMagar COL-APSE was also more sensitive in supporting the growth of Enterobacteriaceae with COL resistance associated with the carriage of mcr-1. Conclusion. CHROMagar COL-APSE is a sensitive and specific medium...

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

Characterization and Testing the Efficiency of Acinetobacter baumannii Phage vB-GEC_Ab-M-G7 as an Antibacterial Agent

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Ia Kusradze

2016-10-01

Full Text Available Acinetobacter baumannii is a gram-negative, non-motile bacterium that, due to its multidrug resistance, has become a major nosocomial pathogen .The increasing number of multidrug resistant (MDR strains has renewed interest in phage therapy. The aim of our study was to assess the effectiveness of phage administration in Acinetobacter baumannii wound infections in an animal model to demonstrate phage therapy as non-toxic, safe and alternative antibacterial remedy. Using classical methods for the study of bacteriophage properties, we characterized phage vB-GEC_Ab-M-G7 as a dsDNA myovirus with a 90kb genome size. Important characteristics of vB-GEC_Ab-M-G7include a short latent period and large burst size, wide host range, resistance to chloroform and thermal and pH stability. In a rat wound model, phage application effectively decreased the number of bacteria isolated from the wounds of successfully treated animals. This study highlights the effectiveness of the phage therapy and provides further insight into treating infections caused by MDR strains using phage administration.

Isolation of Electrogenic Microorganisms with Potential to Reduce Hexavalent Chromium

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Alexander Mora Collazos

2017-01-01

Full Text Available Isolation of cultivable microorganisms was made from the biofilm formed on the anode of a microbial fuel cell put into operation for 30 days; isolated microorganisms were evaluated for their ability to produce energy and reduce the hexavalent chromium Cr (VI. Five microorganisms were isolated, which were characterized by analysis of 16S rRNA gene, placing them in four bacterial genera: Exiguobacterium (CrMFC1, Acinetobacter (CrMFC2, Aeromonas (CrMFC3 and CrMFC5 and Serratia (CrMFC4. All isolates showed electrogenic activity and ability to reduce hexavalent chromium; the Acinetobacter CrMFC1 strain showed the best electrochemical performance registering a maximum power density of 18.61 mW/m2; the other strains showed values of maximum power density between 4.6 mW/m2and 7.1 mW/m2. Strains Aeromonas CrMFC5 and Exiguobacterium CrMFC1 showed the best rates of chromium reduction being able to reduce 100 % of the Cr (VI in less than 24 hours, the Aeromonas CrMFC5 strain was the most efficient, reducing 100 % of Cr (VI in 10 hours; the other strains reduced 100% of the contaminant after 28 to 30 hours. The microorganisms isolated in this study are hardly known for their electrogenic capacity and for reducing Cr (VI; however, show promise for their use in combined systems involving energy production system coupled to bioremediation of chromium contaminated water.

Epidemiology of nosocomial colonization/infection caused by Acinetobacter spp. in patients of six surgical clinics in war and peacetime.

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Suljagić, Vesna; Jevtić, Miodrag; Djordjević, Boban; Romić, Predrag; Ilić, Radoje; Stanković, Nebojsa; Milović, Novak; Novaković, Marijan; Kozarski, Jefta; Roganović, Zoran; Popović, Zoran; Jovelić, Aleksandra

2011-08-01

Acinetobacter spp. has emerged as nosocomial pathogen during the past few decades in hospitals all over the world, but it has increasingly been implicated as a serious nosocomial pathogen in military hospitals. The aim of this study was to analyse and compare the surveillance data on Acinetobacter nosocomial colonization/infection (NCI) collected during the wartime with the data collected in peacetime. We conducted a prospective study of incidence of Acinetobacter spp. colonization/infection. Also, the two nested case-control studies were conducted. The patients with nosocomial infection (cases) were compared with those with nosocomial colonization (controls) during the two different periods, wartime and peacetime. The patients with NCI by Acinetobacter spp. were identified by the case-based surveillance. The surveillance covered all the patients in 6 surgical clinics. During the study periods a total of 166 patients had cultures that grew Acinetobacter spp. and the pooled rates of Acinetobacter spp. colonization and infection were significantly higher in wartime. When patients with NCI in wartime were compared with those with NCI in peacetime significant differences were observed. In the war year, the patients were more significantly males (p war and peace period.

Factors influencing survival in patients with multidrug-resistant Acinetobacter baumannii infection

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Mariana Lima Prata-Rocha

Full Text Available Multidrug-resistant (MDR Acinetobacter baumannii (Acb is a rapidly emerging pathogen in healthcare settings. The aim of this study was to evaluate the predictors of poor outcome in patients with MDR Acb. This is the first report documenting factors influencing survival in patients with MDR Acb in this tertiary hospital. This study is a prospective of the hospital epidemiology database. A total of 73 patients with 84 Acb isolates were obtained between August 2009 and October 2010 in this hospital. In the present study, the 30-day mortality rate was 39.7%. Of 84 Acb isolates, 50 (59% were MDR, nine (11% were pan-resistant, and 25 (30% were non-MDR. The non-MDR isolates were used as the control group. The factors significantly associated with multidrug resistance included previous surgeries, presence of comorbidity (renal disease, use of more than two devices, parenteral nutrition, and inappropriate antimicrobial therapy. Significant predictors of 30-day mortality in the univariate analysis included pneumonia, diabetes mellitus, renal disease, use of more than two devices, and inappropriate antimicrobial therapy administered within two days of the onset of infection. The factors associated with mortality in patients with MDR Acb infection in this study were: age > 60 years, pneumonia, diabetes mellitus, renal disease, use of more than two invasive procedures, and inappropriate antimicrobial therapy. Vigilance is needed to prevent outbreaks of this opportunistic and deadly pathogen.

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

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Bindu Subhadra

2016-02-01

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

Effect of carbapenem consumption patterns on the molecular epidemiology and carbapenem resistance of Acinetobacter baumannii.

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Mózes, Julianna; Ebrahimi, Fatemeh; Gorácz, Orsolya; Miszti, Cecília; Kardos, Gábor

2014-12-01

This study investigated the molecular epidemiology of Acinetobacter baumannii in the University of Debrecen in relation to antibiotic consumption. Overall and ward-specific antibiotic consumption was measured by the number of defined daily doses (DDD) per 100 bed-days between 2002 and 2012. Consumption was analysed against the number of A. baumannii positive patients per 100 bed-days, number of isolates per positive sample, and proportion of carbapenem resistant A. baumannii, using time-series analysis. Altogether 160 A. baumannii isolates from different wards were collected and analysed. Carbapenemase genes bla(OXA-23-like), bla(OXA-24-like), bla(OXA-48-like), bla(OXA-51-like), bla(OXA-58-like) and integrons were sought by PCR. Relatedness of isolates was assessed by PFGE. Prevalence and carbapenem resistance of A. baumannii were statistically associated with carbapenem consumption. Prevalence data followed carbapenem usage with three quarterly lags (r = 0.51-0.53, Pcarbapenem consumption was associated with the carbapenem-susceptible cluster, as well as with the carbapenem-susceptible isolates in the cluster with variable susceptibility. Wards with high carbapenem usage almost exclusively harboured isolates from carbapenem-resistant clusters. All clusters were dominated by isolates of one or two wards, but most wards were represented in multiple clusters. Increases in prevalence and carbapenem resistance of A. baumannii were associated with usage of meropenem and ertapenem but not of imipenem, which led to the spread of multiple clones in the University. © 2014 The Authors.

Characterization of multi-drug resistant ESBL producing nonfermenter bacteria isolated from patients blood samples using phenotypic methods in Shiraz (Iran

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Maneli Amin Shahidi

2015-10-01

Full Text Available Background and Aim: The emergence of  nonfermenter bacteria that are resistant to multidrug resistant ESBL  are  nowadays a principal problem  for hospitalized patients. The present study aimed at surveying the emergence of nonfermenter bacteria resistant to multi-drug ESBL producing isolated from patients blood samples using BACTEC 9240 automatic system in Shiraz. Materials and Methods: In this cross-sectional study, 4825 blood specimens were collected from hospitalized patients in Shiraz (Iran, and positive samples were detected by means of  BACTEC 9240 automatic system. The isolates  containing nonfermenter bacteria were identified based on biochemical tests embedded in the API-20E system. Antibiotic sensitivity  test was performed  and identification of  ESBL producing strains were done  using phenotypic detection of extended spectrum beta-lactamase producing isolates(DDST according to CLSI(2013 guidelines.   Results: Out of 4825 blood samples, 1145 (24% specimen were gram-positive using BACTEC system. Among all isolated microorganisms, 206 isolates were non-fermenting gram- negative bacteria. The most common non-fermenter isolates were Pseudomonas spp. (48%, Acinetobacter spp. (41.7% ,and Stenotrophomonas spp. (8.2%. Seventy of them (81.4% were  Acinetobacter spp. which were ESBL positive. Among &beta-lactam antibiotics, Pseudomonas spp. showed  the best sensitivity to piperacillin-tazobactam (46.5%.  Conclusion: It was found that  &beta-lactam antibiotics are not effective against more than 40% of Pseudomonas spp. infections and 78% Acinetobacter infections. Emergence of multi-drug resistant strains that are resistant to most antibiotic classes is a major public health problem in Iran. To resolve this problem using of practical guidelines is critical.

Reducing the spread of Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus on a burns unit through the intervention of an infection control bundle.

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Barbut, Frédéric; Yezli, Saber; Mimoun, Maurice; Pham, Julien; Chaouat, Marc; Otter, Jonathan A

2013-05-01

Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii are major nosocomial pathogens in burns units. We investigated the impact of an infection control bundle on the incidence of nosocomial MRSA and A. baumannii in our burns unit, comparing a pre-intervention period (December 2006-August 2008) with an intervention period (September 2008-December 2009). The bundle comprised regular hydrogen peroxide vapour (HPV) disinfection of the rooms following discharge of patients colonized or infected by multidrug-resistant bacteria, pre-emptive cohort isolation of newly admitted patients before being proven culture negative, cohorting of colonized or infected patients, installation of two air disinfection systems in the corridors of the unit and improvement of material storage. We also investigated the microbiological efficacy of HPV disinfection by sampling the environment before and after HPV treatments. HPV disinfection eliminated pathogens from the environment and significantly reduced total bacterial surface counts, and total fungal air and surface counts, on both a unit and room scale. The incidence of nosocomial MRSA infection or colonization fell by 89.3% from 7.22 to 0.77 cases/1000 patient days (pcontrol bundle resulted in a significant reduction in the incidence of nosocomial MRSA and A. baumannii in our burns unit and prevented further outbreaks of these organisms. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

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

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Renata Souto

2014-06-01

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

Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus

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Zakaria, Zainul Akmar; Zakaria, Zainoha; Surif, Salmijah; Ahmad, Wan Azlina

2007-01-01

Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L -1 of Cr(VI) was reduced at a flow rate of 8.0 mL min -1 . The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment

Biological detoxification of Cr(VI) using wood-husk immobilized Acinetobacter haemolyticus

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Zakaria, Zainul Akmar; Zakaria, Zainoha [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Surif, Salmijah [Department of Environmental Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Ahmad, Wan Azlina [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)], E-mail: azlina@kimia.fs.utm.my

2007-09-05

Acinetobacter haemolyticus, a Gram-negative aerobic locally isolated bacterium, immobilized on wood-husk showed the ability to detoxify Cr(VI) to Cr(III). Wood-husk, a natural cellulose-based support material, packed in an upward-flow column was used as support material for bacterial attachment. Around 97% of the Cr(VI) in wastewater containing 15 mg L{sup -1} of Cr(VI) was reduced at a flow rate of 8.0 mL min{sup -1}. The wastewater containing Cr(VI) was added with liquid pineapple wastewater as nutrient source for the bacteria. Electron microscopic examinations of the wood-husk after 42 days of column operation showed gradual colonization of the wood-husk by bacterial biofilm. The use of 0.1% (v/v) formaldehyde as a disinfecting agent inhibited growth of bacteria present in the final wastewater discharge. This finding is important in view of the ethical code regarding possible introduction of exogenous bacterial species into the environment.

Dissemination of carbapenem-resistant Acinetobacter baumannii in patients with burn injuries.

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Shoja, Saeed; Moosavian, Mojtaba; Rostami, Soodabeh; Farahani, Abbas; Peymani, Amir; Ahmadi, Khadijeh; Ebrahimifard, Nasim

2017-04-01

Carbapenem-resistant Acinetobacter baumannii has emerged as an important cause of infection in burn patients. This study aimed to characterize the antimicrobial susceptibility pattern, determine the prevalence of oxacillinase and metallo-beta-lactamase (MBL) genes, and type the A. baumannii isolates obtained from burn patients. During a 1-year period, a total of 40 nonduplicated isolates of A. baumannii were obtained from burn patients who were hospitalized in the Taleghani Burn Hospital in Ahvaz, in the southwest of Iran. Testing for antimicrobial susceptibility was carried out by disk diffusion and E-test. To screen MBL production, a double disk synergy and MBL E-test were performed. The presence of bla OXA-23-like , bla OXA-24-like , bla OXA-51-like and bla OXA-58-like , bla VIM , bla IMP and bla SPM , and bla NDM was sought by polymerase chain reaction (PCR). Repetitive extragenic palindromic sequence-based PCR was carried out for determination of isolates clonality. Overall, 92.5% of isolates were carbapenem-resistant. Polymyxin B, colistin, and ampicillin-sulbactam were the most effective agents in vitro, with a susceptibility rate of 100%, 97.5%, and 72.5%, respectively. According to the double disk synergy and E-test, 55.6% and 97.3% of isolates were MBL producers, respectively. Furthermore, 70% of isolates harbored bla OXA-23-like and 20% were positive for bla OXA-24-like. However, no encoding genes were detected for bla VIM , bla IMP and bla SPM , bla NDM , and bla OXA-58-like . Repetitive extragenic palindromic sequence-based PCR revealed that carbapenem-resistant isolates belonged to four clones, including A, B, C, and D; the predominant clones were B and C. The rate of carbapenem resistance was high, and it appeared that bla OXA-23-like and bla OXA-24-like contributed to the carbapenem resistance of A. baumannii isolates. This result suggests that the two predominant clones of A. baumannii were spread among burn patients. In order to prevent future

Synergy of imipenem/colistin methanesulfonate combinations against imipenem-nonsusceptible multidrug-resistant Acinetobacter baumannii.

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Leu, Hsieh-Shong; Ye, Jung-Jr; Lee, Ming-Hsun; Su, Lin-Hui; Huang, Po-Yen; Wu, Tsu-Lan; Huang, Ching-Tai

2014-10-01

The optimal combination ratio of imipenem to colistin methanesulfonate (CMS) against imipenem-nonsusceptible multidrug-resistant Acinetobacter baumannii (INS-MDRAB) has not been determined in previous studies. To provide an alternative therapeutic option for clinical INS-MDRAB isolates, we investigated whether clinically achievable serum concentrations of CMS in combination with imipenem enhance the in vitro activity of imipenem against the INS-MDRAB isolates. Fifty-nine INS-MDRAB isolates with imipenem minimal inhibitory concentration (MIC) values of ≥8 mg/L were selected randomly from the Clinical Microbiology Laboratory at a university-affiliated medical center between July 1998 and May 2005. The in vitro activity of imipenem among these 59 clinical isolates was explored via serial two-fold dilutions containing a range of imipenem concentration from 0.125 mg/L to 256 mg/L, in combination with two fixed CMS concentrations at 0.5 mg/L and 1 mg/L. Genotype classification was performed using the pulsed-field gel electrophoresis method and infrequent-restriction-site polymerase chain reaction. A significant reversal of imipenem resistance (i.e., MICs ≤ 4 mg/L) was observed in 34 (57.6%) isolates and 44 (74.6%) isolates with the tests of CMS concentrations at 0.5 mg/L and 1 mg/L, respectively (p = 0.041). Genotype 1 was predominant (43 isolates, 72.9%) with imipenem resistance reversal rates of 51.2% and 79.1% (p = 0.004) in the tests of CMS at 0.5 mg/L and 1 mg/L, respectively. The synergy of imipenem/CMS against INS-MDRAB was significantly better for the CMS concentration at 1 mg/L than that at 0.5 mg/L, especially in our predominant clone. Our results provided insightful information for treating INS-MDRAB infections in clinical practice. Copyright © 2013. Published by Elsevier B.V.

Weigle Reactivation in Acinetobacter Calcoaceticus

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Berenstein, Dvora

1982-01-01

phage and host survivals of about 5 times 10-6 and 1 times 10-1, respectively. Intracellular development of W-reactivated P78 was followed by one-step growth experiments. Conditions which allowed maximal W-reactivation also extended the period of phage production and yielded a somewhat reduced burst......Weigle (W)-reactivation was demonstrated in Acinetobacter calcoaceticus for the UV-irra-diated lysogenic phage P78. The reactivation factor (survival of irradiated phage on irradiated bacteria/ survival on unirradiated bacteria) reached a maximum value of 20. This was obtained at UV-doses giving...

Screening and Evaluation of the Bioremediation Potential of Cu/Zn-Resistant, Autochthonous Acinetobacter sp. FQ-44 from Sonchus oleraceus L.

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Fang, Qing; Fan, Zhengqiu; Xie, Yujing; Wang, Xiangrong; Li, Kun; Liu, Yafeng

2016-01-01

The quest for new, promising and indigenous plant growth-promoting rhizobacteria and a deeper understanding of their relationship with plants are important considerations in the improvement of phytoremediation. This study focuses on the screening of plant beneficial Cu/Zn-resistant strains and assessment of their bioremediation potential (metal solubilization/tolerance/biosorption and effects on growth of Brassica napus seedlings) to identify suitable rhizobacteria and examine their roles in microbes-assisted phytoremediation. Sixty Cu/Zn-resistant rhizobacteria were initially isolated from Sonchus oleraceus grown at a multi-metal-polluted site in Shanghai, China. From these strains, 19 isolates that were all resistant to 300 mg⋅L -1 Cu as well as 300 mg⋅L -1 Zn, and could simultaneously grow on Dworkin-Foster salt minimal medium containing 1-aminocyclopropane-1-carboxylic acid were preliminarily selected. Of those 19 isolates, 10 isolates with superior plant growth-promoting properties (indole-3-acetic acid production, siderophore production, and insoluble phosphate solubilization) were secondly chosen and further evaluated to identify those with the highest bioremediation potential and capacity for bioaugmentation. Strain S44, identified as Acinetobacter sp. FQ-44 based on 16S rDNA sequencing, was specifically chosen as the most favorable strain owing to its strong capabilities to (1) promote the growth of rape seedlings (significantly increased root length, shoot length, and fresh weight by 92.60%, 31.00%, and 41.96%, respectively) under gnotobiotic conditions; (2) tolerate up to 1000 mg⋅L -1 Cu and 800 mg⋅L -1 Zn; (3) mobilize the highest concentrations of water-soluble Cu, Zn, Pb, and Fe (16.99, 0.98, 0.08, and 3.03 mg⋅L -1 , respectively); and (4) adsorb the greatest quantities of Cu and Zn (7.53 and 6.61 mg⋅g -1 dry cell, respectively). Our findings suggest that Acinetobacter sp. FQ-44 could be exploited for bacteria-assisted phytoextraction

A Pathogenic Potential of Acinetobacter baumannii-Derived Membrane Vesicles

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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.

Antimicrobial Resistance and Resistance Genes in Aerobic Bacteria Isolated from Pork at Slaughter.

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Li, Lili; Heidemann Olsen, Rikke; Ye, Lei; Yan, He; Nie, Qing; Meng, Hecheng; Shi, Lei

2016-04-01

The aim of this study was to investigate the phenotypic and genotypic antimicrobial resistance, integrons, and transferability of resistance markers in 243 aerobic bacteria recovered from pork at slaughter in the People's Republic of China. The organisms belonged to 22 genera of gram-negative bacteria (92.2%) and gram-positive bacteria (7.8%). High levels of resistance were detected to tetracycline, trimethoprim-sulfamethoxazole, and ampicillin (36.2 to 54.3%), and lower levels were detected to nitrofurantoin, cefotaxime, gentamicin, ciprofloxacin, and chloramphenicol (7.8 to 29.2%). Across species, genes conferring antimicrobial resistance were observed with the following frequencies: blaTEM, 40.7%; blaCMY-2, 15.2%; blaCTX-M, 11.5%; sul2, 27.2%; sul1, 14.4%; tet(A), 5.4%; tet(L), 5.4%; tet(M), 5.0%; tet(E), 3.7%; tet(C), 3.3%; tet(S), 2.5%; and tet(K), 0.8%. Various antimicrobial resistance genes were found in new carriers: blaTEM in Lactococcus garvieae, Myroides odoratimimus, Aeromonas hydrophila, Staphylococcus sciuri, Raoultella terrigena, Macrococcus caseolyticus, Acinetobacter ursingii, Sphingobacterium sp., and Oceanobacillus sp.; blaCMY-2 in Lactococcus lactis, Klebsiella oxytoca, Serratia marcescens, Acinetobacter baumannii, and Myroides phaeus; tet(L) in M. caseolyticus; sul1 in Vibrio cincinnatiensis; sul2 in Acinetobacter bereziniae, Acinetobacter johnsonii, and V. cincinnatiensis; and the class 1 integron and gene cassette aadA2 in V. cincinnatiensis. Approximately 6.6% of isolates contained class 1 integrons, and one isolate harbored class 2 integrons. Plasmid associated intI1 and androgen receptor- encoding genes were transferred into Escherichia coli J53 and E. coli DH5α by conjugation and transformation experiments, respectively. Our study highlights the importance of aerobic bacteria from pork as reservoirs for antimicrobial resistance genes and mobile genetic elements that can readily be transferred intra- and interspecies.

Characterization of the Extended-Spectrum beta-Lactamase Producers among Non-Fermenting Gram-Negative Bacteria Isolated from Burnt Patients

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Mojdeh Hakemi Vala

2013-09-01

Full Text Available Please cite this article as: Hakemi Vala M, Hallajzadeh M, Fallah F, Hashemi A, Goudarzi H. Characterization of the extended-spectrum beta-lactamase producers among non-fermenting gram-negative bacteria isolated from burnt patients. Arch Hyg Sci 2013;2(1:1-6. Background & Aims of the Study: Extended-spectrum beta-Lactamases (ESBLs represent a major group of beta-lactamases which are responsible for resistance to oxyimino-cephalosporins and aztreonam and currently being identified in large numbers throughout the world. The objective of this study was to characterize ESBL producers among non-fermenter gram-negative bacteria isolated from burnt patients. Materials & Methods: During April to July 2012, 75 non-fermenter gram-negative bacilli were isolated from 240 bacterial cultures collected from wounds of burnt patients admitted to the Burn Unit at Shahid Motahari Hospital (Tehran, Iran. Bacterial isolation and identification was done using standard methods. Antimicrobial susceptibility testing was performed by disk diffusion method for all strains against selected antibiotics and minimum inhibitory concentration was determined by microdilution test. The ability to produce ESBL was detected through double disk synergy test among candidate strains. Results: Of 75 non-fermenter isolates, 47 Pseudomonas aeruginosa and 28 Acinetobacter baumannii were identified. The resistance of P. aeruginosa isolates to tested antibiotics in antibiogram test were 100% to cefpodoxime, 82.98% to ceftriaxone, 78.73% to imipenem, 75% to meropenem, 72.72% to gentamicin, 69.23% to ciprofloxacin and aztreonam, 67.57% to cefepime, 65.95% to ceftazidime, and 61.53% to piperacillin. The results for Acinetobacter baumannii were 100% to ceftazidime, cefepime, ciprofloxacin, imipenem, meropenem, cefpodoxime, and cefotaxim, 96.85% to gentamicin, 89.65% to ceftriaxone, 65.51% to aztreonam, and 40% to piperacillin. Double disk synergy test showed that 21 (28% of non

The Genomic Diversification of the Whole Acinetobacter Genus: Origins, Mechanisms, and Consequences

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Touchon, Marie; Cury, Jean; Yoon, Eun-Jeong; Krizova, Lenka; Cerqueira, Gustavo C.; Murphy, Cheryl; Feldgarden, Michael; Wortman, Jennifer; Clermont, Dominique; Lambert, Thierry; Grillot-Courvalin, Catherine; Nemec, Alexandr; Courvalin, Patrice; Rocha, Eduardo P.C.

2014-01-01

Bacterial genomics has greatly expanded our understanding of microdiversification patterns within a species, but analyses at higher taxonomical levels are necessary to understand and predict the independent rise of pathogens in a genus. We have sampled, sequenced, and assessed the diversity of genomes of validly named and tentative species of the Acinetobacter genus, a clade including major nosocomial pathogens and biotechnologically important species. We inferred a robust global phylogeny and delimited several new putative species. The genus is very ancient and extremely diverse: Genomes of highly divergent species share more orthologs than certain strains within a species. We systematically characterized elements and mechanisms driving genome diversification, such as conjugative elements, insertion sequences, and natural transformation. We found many error-prone polymerases that may play a role in resistance to toxins, antibiotics, and in the generation of genetic variation. Surprisingly, temperate phages, poorly studied in Acinetobacter, were found to account for a significant fraction of most genomes. Accordingly, many genomes encode clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems with some of the largest CRISPR-arrays found so far in bacteria. Integrons are strongly overrepresented in Acinetobacter baumannii, which correlates with its frequent resistance to antibiotics. Our data suggest that A. baumannii arose from an ancient population bottleneck followed by population expansion under strong purifying selection. The outstanding diversification of the species occurred largely by horizontal transfer, including some allelic recombination, at specific hotspots preferentially located close to the replication terminus. Our work sets a quantitative basis to understand the diversification of Acinetobacter into emerging resistant and versatile pathogens. PMID:25313016

Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii.

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Xiao, Shu-Zhen; Chu, Hai-Qing; Han, Li-Zhong; Zhang, Zhe-Min; Li, Bing; Zhao, Lan; Xu, Liyun

2016-09-01

The aim of the study was to investigate the resistant mechanisms and homology of imipenem-resistant Acinetobacter baumannii (A. baumannii). A total of 46 non-duplicate imipenem‑resistant A. baumannii clinical isolates were collected from three tertiary hospitals between July, 2011 and June, 2012. The minimal inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Phenylalanine‑arginine β-naphthylamide was used to detect the presence of the efflux pump-mediated resistant mechanism. Polymerase chain reaction was employed to amplify genes associated with drug resistance, including β‑lactamase genes, efflux pump genes and outer membrane protein gene CarO. A few amplicons were randomly selected and sequenced. Multilocus sequence analysis (MLST) was employed in typing A. baumanni. A. baumannii was resistant to imipenem, simultaneously showing resistance to several other antimicrobials. In addtition, 13 A. baumannii were found to mediate drug resistance through operation of the efflux pump. Of the various drug resistance genes tested, blaOXA‑51 was present in 46 isolates, blaOXA‑23 gene was present in 44 isolates and blaNDM gene was found in only one strain. Other drug resistant‑associated genes, including blaKPC, blaIMP, blaOXA-24, blaOXA‑58, blaSHV, blaGIM and blaVIM were not detected. Mutation of adeS and outer membrane protein gene CarO were found in a few of the imipenem‑resistant isolates. The MLST analysis revealed that all 46 clinical isolates were clustered into 11 genotypes and the most frequent genotype was ST208. In conclusion, β‑lactamase genes, genes involved in efflux pump and mutation of outer membrane protein encoding gene may be important in mediating imipenem resistance in A. baumannii. Of the 11 different genotypes, ST11 was shared by the majority of A. baumannii, which may be due to horizontal transfer of patients from hospitals.

In vitro Evaluation of the Colistin-Carbapenem Combination in Clinical Isolates of A. baumannii Using the Checkerboard, Etest, and Time-Kill Curve Techniques

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Micheline A. H. Soudeiha

2017-05-01

Full Text Available The worldwide increase in the emergence of carbapenem resistant Acinetobacter baumannii (CRAB calls for the investigation into alternative approaches for treatment. This study aims to evaluate colistin-carbapenem combinations against Acinetobacter spp., in order to potentially reduce the need for high concentrations of antibiotics in therapy. This study was conducted on 100 non-duplicate Acinetobacter isolates that were collected from different patients admitted at Saint George Hospital-University Medical Center in Beirut. The isolates were identified using API 20NE strips, which contain the necessary agents to cover a panel of biochemical tests, and confirmed by PCR amplification of blaOXA−51−like. Activities of colistin, meropenem and imipenem against Acinetobacter isolates were determined by ETEST and microdilution methods, and interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. In addition, PCR amplifications of the most common beta lactamases contributing to carbapenem resistance were performed. Tri locus PCR–typing was also performed to determine the international clonality of the isolates. Checkerboard, ETEST and time kill curves were then performed to determine the effect of the colistin-carbapenem combinations. The synergistic potential of the combination was then determined by calculating the Fractional Inhibitory Concentration Index (FICI, which is an index that indicates additivity, synergism, or antagonism between the antimicrobial agents. In this study, 84% of the isolates were resistant to meropenem, 78% to imipenem, and only one strain was resistant to colistin. 79% of the isolates harbored blaOXA−23−like and pertained to the International Clone II. An additive effect for the colistin-carbapenem combination was observed using all three methods. The combination of colistin-meropenem showed better effects as compared to colistin-imipenem (p < 0.05. The colistin-meropenem and

Rare cutaneous infection by Acinetobacter baumannii in an immunocompetent patient: a case report

OpenAIRE

Cirino, Pablo Vitoriano; Guimarães, Newton Sales; Follador, Ivonise

2008-01-01

O Acinetobacter baumanni é patógeno oportunista antigamente considerado de baixa virulência. Atualmente está envolvido em processos infecciosos que acometem pacientes imunocomprometidos,grandes queimados e pacientes em unidades de terapia intensiva que fazem uso de ventilação mecânica. Esse relato de caso chama atenção para infecção cutânea rara por essa bactéria em paciente imunocompetente.Acinetobacter baumannii is an oportunistic pathogen that used to be considered as having low virulence;...

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

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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.

A novel mutation in pmrB mediates colistin resistance during therapy of Acinetobacter baumannii.

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Dahdouh, Elias; Gómez-Gil, Rosa; Sanz, Sonia; González-Zorn, Bruno; Daoud, Ziad; Mingorance, Jesús; Suárez, Monica

2017-06-01

Acinetobacter baumannii is a highly versatile nosocomial pathogen. Multidrug resistance among A. baumannii isolates led to the use of colistin, subsequently giving rise to colistin-resistant strains. In this study, the genetic and phenotypic profiles of two colistin-resistant A. baumannii isolates were investigated. Two A. baumannii isolates were obtained from Patient 1 (C071 and C440) and three isolates were obtained from Patient 2 (C080, C314 and C428). Susceptibility profiles were determined by VITEK ® 2 and Etest. Clonality was determined by RAPD analysis and trilocus multiplex PCR. The pmrCAB operon was sequenced and common carbapenemase genes were screened for by PCR. Doubling times, haemolysis, surface motility, biofilm formation, siderophore production and proteolytic activity were phenotypically determined. Finally, whole-genome sequencing was performed for all five isolates. Isolates C440 and C428 were resistant to colistin and were clonally identical to their sensitive counterparts. The cause of colistin resistance was traced to the previously described P233S mutation in pmrB of C440 and to a novel ΔI19 mutation in pmrB of C428. bla OXA-58-like and bla GES-5 from the strains of Patients 1 and 2, respectively, were also detected. C440 had attenuated proteolytic activity and was positive for siderophore production compared with C071. No difference in in vitro virulence was detected between isolates C080, C314 and C428. In conclusion, one common and one novel mutation were encountered in pmrB from two distinct colistin-resistant A. baumannii isolates. These mutations caused colistin resistance during therapy in two distinct clones, and only one of them had altered in vitro virulence. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Antimicrobial resistance of Escherichia coli isolated in newly-hatched chickens and effect of amoxicillin treatment during their growth.

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Jiménez-Belenguer, Ana; Doménech, Eva; Villagrá, Arantxa; Fenollar, Alejandro; Ferrús, Maria Antonia

2016-08-01

The use of antimicrobials in food animals is the major determinant for the propagation of resistant bacteria in the animal reservoir. However, other factors may also play a part, and in particular vertical spread between the generations has been suggested to be an important transmission pathway. The objective of this paper was to determine the resistance patterns of Escherichia coli isolated from newly-hatched chickens as well as to study the antibiotic pressure effect when amoxicillin was administered during their growing period. With this aim, meconium from 22 one-day-old Ross chickens was analysed. In addition, during their growth period, amoxicillin treatments at days 7, 21 and 35 were carried out. Results showed a high number of E. coli-resistant strains were isolated from the treated one-day-old chickens, and were the highest for β-lactams group, followed by quinolone and tetracyclines. After treatment with amoxicillin, the highest percentage of resistances were detected for this antibiotic compared to the others analysed, with significant differences in resistance percentages between control and treated broilers detected in relation to ampicillin, cephalothin, streptomycin, kanamycin, gentamicin, chloramphenicol and tetracycline. Differences in resistances to ciprofloxacin and nalidixic acid between control and treated animals were not observed and there was lack of resistance for amikacin and ceftriaxone. These results suggest the possibility of vertical transmission of resistant strains to newly-hatched chicks from parent flocks, and seem to indicate that the treatment with amoxicillin increased the resistance of E. coli to other antibiotics.

Investigation of Extensively Drug-Resistant blaOXA-23-Producing Acinetobacter baumannii Spread in a Greek Hospital.

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Mavroidi, Angeliki; Katsiari, Maria; Palla, Eleftheria; Likousi, Sofia; Roussou, Zoi; Nikolaou, Charikleia; Platsouka, Evangelia D

2017-06-01

A rapid increase was observed in the incidence of extensively drug-resistant Acinetobacter baumannii (XDR Aba) isolates in a Greek hospital during 2014. To investigate the causes of this rise, the antimicrobial resistance profiles of all carbapenem-resistant (CARB-R) Aba isolates recovered during 2014-2015 were determined. Selected XDR Aba isolates (n = 13) were characterized by molecular methods. XDR Aba (48 isolates) represented 21.4% of the 224 CARB-R Aba recovered during the study period. The 13 selected XDR Aba isolates were positive for the blaOXA-23, the intrinsic blaOXA-51, and the adeB gene of the AdeABC efflux pump, and all belonged to the 3LST ST101, corresponding to the international clone II. Three bloodstream isolates possessed two amino acid substitutions (A138T+A226V) in the deduced amino acid sequences of the pmrB gene, which may be implicated in colistin resistance. This study demonstrates that this clone still evolves by obtaining an ever-increasing arsenal of antibiotic resistance mechanisms. The clinical characteristics of the intensive care unit (ICU) patients with XDR Aba were reviewed retrospectively. Infected ICU patients with XDR Aba displayed higher death rates compared with infected ICU patients susceptible to colistin and tigecycline CARB-R Aba, although there were no statistically significant differences. Conclusively, continuous surveillance and molecular characterization of XDR Aba, combined with strict infection control measures are mandatory for combating nosocomial infections caused by this organism.

Detection of blaOXA-23-like and blaNDM-1 in Acinetobacter baumannii from the Eastern Region, Saudi Arabia.

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El-Mahdy, Taghrid S; Al-Agamy, Mohamed H; Al-Qahtani, Ahmed A; Shibl, Atef M

2017-01-01

Acinetobacter baumannii is currently considered as one of the most common successful pathogens in the healthcare system due to its ability to quickly develop resistance. Ten carbapenem-resistant A. calcoaceticus-baumannii complex were isolated from the eastern region, Saudi Arabia in 2014. All isolates were resistant to ciprofloxacin, however, 8 of 10 isolates were tigecycline resistant. Susceptibility test was also carried out for three aminoglycosides, resistance to gentamicin was 80%, amikacin was 90%, and tobramycin was 50%. Colistin susceptibility was seen in all isolates. The 10 isolates harbored bla OXA-23-like and ISAba1 and 9 of them also carried bla ADC . Three isolates of 10 harbored bla NDM-1 coding for NDM metallo-β-lactamase (MBL) with coexistence of bla ADC together with either bla GES or bla TEM or both. Those three isolates exhibited negative Etest MBL screening test. Pulsed-field gel electrophoresis revealed the high clonal variability of the isolates, although two isolates were indistinguishable. The risk of dissemination of carbapenem resistance through presence of ISAba1 upstream of OXA-23-like in all isolates raises the concern about emergence of higher carbapenem prevalence rates in the future in our region. This study also demonstrated the importance of molecular surveillance to provide accurate and reliable data about the resistance rates of A. baumannii. Finally, the high incidence of NDM-1 among our isolates requires a routine surveillance to monitor the future prevalence of this enzyme in the region.

Molecular detection of Acinetobacter species in lice and keds of domestic animals in Oromia Regional State, Ethiopia.

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Bersissa Kumsa

Full Text Available This study was conducted to determine the presence of Acinetobacter and Rickettsia species DNA in lice and Melophagus ovinus (sheep ked of animals from Oromia Regional State in Ethiopia. From September through November 2011, a total of 207 cattle, 85 sheep, 47 dogs and 16 cats were examined for ectoparasites. Results of morphological identification revealed several species of ectoparasites: Linognathus vituli (L. vituli, Bovicola bovis (B. bovis and Solenopotes capillatus (S. capillatus on cattle; B. ovis and Melophagus ovinus (M. ovinus on sheep; and Heterodoxus spiniger (H. spiniger on dogs. There was a significantly (p≤0.0001 higher prevalence of L. vituli observed in cattle than both S. capillatus and B. bovis. Molecular identification of lice using an 18S rRNA gene analysis confirms the identified lice species by morphological methods. We detected different Acinetobacter species among lice (11.1% and keds (86.4% including A. soli in L. vituli of cattle, A. lowffii in M. ovinus of sheep, A. pittii in H. spiniger of dogs, 1 new Acinetobacter spp. in M. ovinus and 2 new Acinetobacter spp. in H. spiniger of dogs using partial rpoB gene sequence analysis. There was a significantly higher prevalence of Acinetobacter spp. in keds than in lice (p≤0.00001. Higher percentage of Acinetobacter spp. DNA was detected in H. spiniger than in both B. ovis and L. vituli (p≤0.00001. Carbapenemase resistance encoding genes for blaOXA-23, blaOXA-24, blaOXA-58, blaNDM-1 and blaOXA-51 were not found in any lice and keds. These findings suggest that synanthropic animals and their ectoparasites might increase the risk of human exposure to zoonotic pathogens and could be a source for Acinetobacter spp. infections in humans. However, additional epidemiological data are required to determine whether ectoparasites of animals can act as environmental reservoirs and play a role in spreading these bacteria to both animal and human hosts.

Molecular detection of Acinetobacter species in lice and keds of domestic animals in Oromia Regional State, Ethiopia.

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Kumsa, Bersissa; Socolovschi, Cristina; Parola, Philippe; Rolain, Jean-Marc; Raoult, Didier

2012-01-01

This study was conducted to determine the presence of Acinetobacter and Rickettsia species DNA in lice and Melophagus ovinus (sheep ked) of animals from Oromia Regional State in Ethiopia. From September through November 2011, a total of 207 cattle, 85 sheep, 47 dogs and 16 cats were examined for ectoparasites. Results of morphological identification revealed several species of ectoparasites: Linognathus vituli (L. vituli), Bovicola bovis (B. bovis) and Solenopotes capillatus (S. capillatus) on cattle; B. ovis and Melophagus ovinus (M. ovinus) on sheep; and Heterodoxus spiniger (H. spiniger) on dogs. There was a significantly (p≤0.0001) higher prevalence of L. vituli observed in cattle than both S. capillatus and B. bovis. Molecular identification of lice using an 18S rRNA gene analysis confirms the identified lice species by morphological methods. We detected different Acinetobacter species among lice (11.1%) and keds (86.4%) including A. soli in L. vituli of cattle, A. lowffii in M. ovinus of sheep, A. pittii in H. spiniger of dogs, 1 new Acinetobacter spp. in M. ovinus and 2 new Acinetobacter spp. in H. spiniger of dogs using partial rpoB gene sequence analysis. There was a significantly higher prevalence of Acinetobacter spp. in keds than in lice (p≤0.00001). Higher percentage of Acinetobacter spp. DNA was detected in H. spiniger than in both B. ovis and L. vituli (p≤0.00001). Carbapenemase resistance encoding genes for blaOXA-23, blaOXA-24, blaOXA-58, blaNDM-1 and blaOXA-51 were not found in any lice and keds. These findings suggest that synanthropic animals and their ectoparasites might increase the risk of human exposure to zoonotic pathogens and could be a source for Acinetobacter spp. infections in humans. However, additional epidemiological data are required to determine whether ectoparasites of animals can act as environmental reservoirs and play a role in spreading these bacteria to both animal and human hosts.

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

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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.

Celulitis por Acinetobacter junii-johnsonii adquirida en la comunidad: una presentación de caso

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Andrés F. Henao-Martínez

2012-06-01

Full Text Available La infección de piel y tejidos blandos por Acinetobacter no relacionada con trauma es una presentación inusual. La mayoría de los casos descritos presentan enfermedades concomitantes y son causados por Acinetobacter baumanii. Se describe un caso de celulitis no traumática por A. junii-johnsonii con bacteriemia, de inicio en la comunidad y asociado con el tratamiento médico. De acuerdo con nuestro conocimiento, éste sería el primer caso reportado de infección de tejidos blandos y piel por A. juniijohnsonii.La vesícula hemorrágica podría ser una característica clínica de celulitis por Acinetobacter.   doi: http://dx.doi.org/10.7705/biomedica.v32i2.652

Pneumonia adquirida na comunidade numa criança saudável por Acinetobacter

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G. Moreira Silva

2012-03-01

Full Text Available Resumo: O género Acinetobacter tem sido implicado numa grande variedade de doenças infecciosas, em particular, nas infecções associadas aos cuidados de saúde. Actualmente há evidência a enfatizar o papel deste microrganismo nas infecções adquiridas na comunidade.É relatado o caso de uma criança previamente saudável, de 28 meses de idade, internada por febre associada a tosse e dor localizada no hemitórax esquerdo e cuja radiografia torácica revelou pneumonia necrotisante do lobo inferior. A investigação diagnóstica efetuada permitiu o diagnóstico de Pneumonia adquirida na comunidade a Acinetobacter lwoffii.A criança partilhava frequentemente o seu equipamento respiratório com familiares idosos com doença pulmonar crónica obstrutiva. Dado não terem sido apurados outros factores de risco, considera-se que a partilha do equipamento poderá ter sido o foco infeccioso.Os autores pretendem alertar para a possibilidade de Pneumonia adquirida na comunidade por Acinetobacter lwoffii, numa criança previamente saudável, relacionada com o mau uso e limpeza dos nebulizadores. Este caso realça o papel emergente desta bactéria, mesmo no contexto comunitário. Abstract: Acinetobacter is involved in a variety of infectious diseases primarily associated with healthcare. Recently there has been increasing evidence of the important role these pathogens play in community acquired infections.We report on the case of a previously healthy child, aged 28 months, admitted for fever, cough and pain on the left side of the chest, which on radiographic examination corresponded to a lower lobe necrotizing pneumonia. After detailed diagnostic work–up, community acquired Acinetobacter lwoffii pneumonia was diagnosed.The child had frequently shared respiratory equipment with elderly relatives with chronic obstructive pulmonary disease. As there were no other apparent risk factors, it could

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. PMID:23527001

Acinetobacter species in the hospital environment : tracing and epidemiology.

NARCIS (Netherlands)

L. Dijkshoorn-de Bruin (Lenie)

1990-01-01

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

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

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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.

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

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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. Copyright © 2016 Elsevier B.V. All rights reserved.

Antimicrobial activity of photodynamic therapy in combination with colistin against a pan-drug resistant Acinetobacter baumannii isolated from burn patient.

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Boluki, Ebrahim; Kazemian, Hossein; Peeridogaheh, Hadi; Alikhani, Mohammad Yousef; Shahabi, Sima; Beytollahi, Leili; Ghorbanzadeh, Roghayeh

2017-06-01

Nosocomially-acquired multi-, extensively-, and pandrug resistant (MDR, XDR, and PDR) strains of microorganisms such as Acinetobacter baumannii remain a serious cause of infection and septic mortality in burn patients. Treatment of patients with nosocomial burn wound infections is often complicated by drug-resistant strains of A. baumannii. Today, many researchers are focusing on the investigation of novel non-antibiotic strategies such as photodynamic therapy (PDT). We report a new PDT strategy that suppresses colistin resistance in PDR A. baumannii by interfering with the expression of a pmrA/pmrB two-component system. In the current study, A. baumannii with a PDR feature isolated from a burn patient was used as a test strain. PDT was carried out using toluidine blue O (TBO) and light-emitting diode (LED) as a photosensitizer and radiation source, respectively. The antimicrobial susceptibility profiles were assessed for cells surviving PDT. The effects of sub-lethal PDT (sPDT) on the expression of the pmrA/pmrB two-component signal transduction system were evaluated by real-time quantitative reverse transcription PCR. Results of drug susceptibly testing (DST) in LED and TBO groups separately showed that the bacteria were resistant to all tested antibiotics, while the DST result of the LED+TBO group showed highly declining bacterial growth when compared with the control group. Reduction in the expression of pmrA and pmrB was observed in the treated strains after sPDT. This represents the first conclusive example of a direct role for the PDT in breaking antibiotic resistance by directly modulating two-component system activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Clinical strains of acinetobacter classified by DNA-DNA hybridization

International Nuclear Information System (INIS)

Tjernberg, I.; Ursing, J.

1989-01-01

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

Clinical strains of acinetobacter classified by DNA-DNA hybridization

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

1989-01-01

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

High-temperature ethanol production using thermotolerant yeast newly isolated from Greater Mekong Subregion

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Atiya Techaparin

Full Text Available Abstract The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. Two hundred and thirty-four yeast isolates from Greater Mekong Subregion (GMS countries, i.e., Thailand, The Lao People's Democratic Republic (Lao PDR and Vietnam were obtained. Five thermotolerant yeasts, designated Saccharomyces cerevisiae KKU-VN8, KKU-VN20, and KKU-VN27, Pichia kudriavzevii KKU-TH33 and P. kudriavzevii KKU-TH43, demonstrated high temperature and ethanol tolerance levels up to 45 °C and 13% (v/v, respectively. All five strains produced higher ethanol concentrations and exhibited greater productivities and yields than the industrial strain S. cerevisiae TISTR5606 during high-temperature fermentation at 40 °C and 43 °C. S. cerevisiae KKU-VN8 demonstrated the best performance for ethanol production from glucose at 37 °C with an ethanol concentration of 72.69 g/L, a productivity of 1.59 g/L/h and a theoretical ethanol yield of 86.27%. The optimal conditions for ethanol production of S. cerevisiae KKU-VN8 from sweet sorghum juice (SSJ at 40 °C were achieved using the Box-Behnken experimental design (BBD. The maximal ethanol concentration obtained during fermentation was 89.32 g/L, with a productivity of 2.48 g/L/h and a theoretical ethanol yield of 96.32%. Thus, the newly isolated thermotolerant S. cerevisiae KKU-VN8 exhibits a great potential for commercial-scale ethanol production in the future.

'Synthetic lipase' production from a newly isolated Sporidiobolus pararoseus strain by submerged fermentation

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Alessandra Smaniotto

2012-12-01

Full Text Available The lipase produced by a newly isolate Sporidiobolus pararoseus strain has potential catalysis ability for esterification reactions. In order to improve its synthetic activity, this work aimed at optimizing 'synthetic lipase' production by submerged fermentation of a conventional media based on peptone, yeast extract, NaCl and olive oil using experimental design technique. According to the results obtained in the first experimental design (2(4-1, yeast extract and NaCl concentrations were tested to further optimization by response surface methodology. The maximum 'synthetic lipase' activity obtained was 26.9 U/mL in the optimized media (5.0, 6.8, 7.0 and 1.0% (wt/v of peptone, yeast extract, NaCl and olive oil, respectively, representing a 6.36-fold increase compared to the initial medium. The time course of 'synthetic lipase' production in the optimized condition was evaluated in terms of synthetic activity, protease activity, biomass and total carbon and the maximum synthetic activity was observed during the stationary phase of growth.

Effect of heavy metals ondecolorization of reactive brilliant red by newly isolated microorganisms

International Nuclear Information System (INIS)

Nosheen, S.; Arshad, M.

2011-01-01

This study involves aerobic decolorisation of reactive azo dye reactive brilliant red 2KBP by newly isolated microbial strains (two bacterial and one fungal strain) in presence of heavy metals including cobalt chloride, ferric chloride, zinc sulphate, copper sulphate and nickel chloride. Many heavy metals are necessary for microbial growth and are required in very small amounts however at higher levels they become toxic. So was the objective of present work to check the effect of concentration of heavy metals on the potential of microbial strains to decolorize azo dyes. All the heavy metals under consideration were added in range of 0.5 gl-1-2.5gl/sup -1/. All heavy metals showed inhibitory effect on decolorization capacity of bacterial as well as fungal strain .At optimum conditions bacterial strains named as B1 and B2 removed 84% and 78% while fungal strain decolorized 90.4% of dye. Cobalt and nickel showed greater inhibitors on% decolorization of dyes than Zinc and iron. Fungal strain showed greater negative effect. Heavy metals might affect enzyme activities and thus reducing removal of dye. (author)

K19 capsular polysaccharide of Acinetobacter baumannii is produced via a Wzy polymerase encoded in a small genomic island rather than the KL19 capsule gene cluster.

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Kenyon, Johanna J; Shneider, Mikhail M; Senchenkova, Sofya N; Shashkov, Alexander S; Siniagina, Maria N; Malanin, Sergey Y; Popova, Anastasiya V; Miroshnikov, Konstantin A; Hall, Ruth M; Knirel, Yuriy A

2016-08-01

Polymerization of the oligosaccharides (K units) of complex capsular polysaccharides (CPSs) requires a Wzy polymerase, which is usually encoded in the gene cluster that directs K unit synthesis. Here, a gene cluster at the Acinetobacter K locus (KL) that lacks a wzy gene, KL19, was found in Acinetobacter baumannii ST111 isolates 28 and RBH2 recovered from hospitals in the Russian Federation and Australia, respectively. However, these isolates produced long-chain capsule, and a wzy gene was found in a 6.1 kb genomic island (GI) located adjacent to the cpn60 gene. The GI also includes an acetyltransferase gene, atr25, which is interrupted by an insertion sequence (IS) in RBH2. The capsule structure from both strains was →3)-α-d-GalpNAc-(1→4)-α-d-GalpNAcA-(1→3)-β-d-QuipNAc4NAc-(1→, determined using NMR spectroscopy. Biosynthesis of the K unit was inferred to be initiated with QuiNAc4NAc, and hence the Wzy forms the β-(1→3) linkage between QuipNAc4NAc and GalpNAc. The GalpNAc residue is 6-O-acetylated in isolate 28 only, showing that atr25 is responsible for this acetylation. The same GI with or without an IS in atr25 was found in draft genomes of other KL19 isolates, as well as ones carrying a closely related CPS gene cluster, KL39, which differs from KL19 only in a gene for an acyltransferase in the QuiNAc4NR synthesis pathway. Isolates carrying a KL1 variant with the wzy and atr genes each interrupted by an ISAba125 also have this GI. To our knowledge, this study is the first report of genes involved in capsule biosynthesis normally found at the KL located elsewhere in A. baumannii genomes.

The genomic diversification of the whole Acinetobacter genus: origins, mechanisms, and consequences.

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Touchon, Marie; Cury, Jean; Yoon, Eun-Jeong; Krizova, Lenka; Cerqueira, Gustavo C; Murphy, Cheryl; Feldgarden, Michael; Wortman, Jennifer; Clermont, Dominique; Lambert, Thierry; Grillot-Courvalin, Catherine; Nemec, Alexandr; Courvalin, Patrice; Rocha, Eduardo P C

2014-10-13

Bacterial genomics has greatly expanded our understanding of microdiversification patterns within a species, but analyses at higher taxonomical levels are necessary to understand and predict the independent rise of pathogens in a genus. We have sampled, sequenced, and assessed the diversity of genomes of validly named and tentative species of the Acinetobacter genus, a clade including major nosocomial pathogens and biotechnologically important species. We inferred a robust global phylogeny and delimited several new putative species. The genus is very ancient and extremely diverse: Genomes of highly divergent species share more orthologs than certain strains within a species. We systematically characterized elements and mechanisms driving genome diversification, such as conjugative elements, insertion sequences, and natural transformation. We found many error-prone polymerases that may play a role in resistance to toxins, antibiotics, and in the generation of genetic variation. Surprisingly, temperate phages, poorly studied in Acinetobacter, were found to account for a significant fraction of most genomes. Accordingly, many genomes encode clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems with some of the largest CRISPR-arrays found so far in bacteria. Integrons are strongly overrepresented in Acinetobacter baumannii, which correlates with its frequent resistance to antibiotics. Our data suggest that A. baumannii arose from an ancient population bottleneck followed by population expansion under strong purifying selection. The outstanding diversification of the species occurred largely by horizontal transfer, including some allelic recombination, at specific hotspots preferentially located close to the replication terminus. Our work sets a quantitative basis to understand the diversification of Acinetobacter into emerging resistant and versatile pathogens. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society

Characterization and plasmid elimination of NDM-1-producing Acinetobacter calcoaceticus from China.

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Yang Sun

Full Text Available The presence of multidrug-resistant bacterial pathogens in the environment poses a serious threat to public health. The opportunistic Acinetobacter spp. are among the most prevalent causes of nosocomial infections. Here, we performed complete genome sequencing of the Acinetobacter calcoaceticus strain XM1570, which was originally cultivated from the sputum of a patient diagnosed with pneumonia in Xiamen in 2010. We identified carbapenem resistance associated gene bla(NDM-1 located on a 47.3-kb plasmid. Three methods--natural reproduction, sodium dodecyl sulfate treatment and nalidixic acid treatment--were used to eliminate the bla(NDM-1-encoding plasmid, which achieved elimination rates of 3.32% (10/301, 83.78% (278/332, and 84.17% (298/354, respectively. Plasmid elimination dramatically increased antibiotic sensitivity, reducing the minimum bacteriostatic concentration of meropenem from 256 µg/ml in the clinical strain to 0.125 µg/ml in the plasmid-eliminated strain. Conjugation transfer assays showed that the bla(NDM-1-containing plasmid could be transferred into Escherichia coli DH5α:pBR322 in vitro as well as in vivo in mice. The bla(NDM-1 genetic environment was in accordance with that of other bla(NDM-1 genes identified from India, Japan, and Hong-Kong. The multilocus sequence type of the isolate was identified as ST-70. Two novel genes encoding intrinsic OXA and ADC were identified and named as OXA-417 and ADC-72. The finding of bla(NDM-1 in species like A. calcoaceticus demonstrates the wide spread of this gene in gram-negative bacteria which is possible by conjugative plasmid transfer. The results of this study may help in the development of a treatment strategy for controlling NDM-1 bacterial infection and transmission.

First report of an OXA-58 carbapenemase-producing Acinetobacter ...

African Journals Online (AJOL)

S. Natoubi

2016-11-18

Nov 18, 2016 ... urinary tract infection, in Morocco. Acinetobacter baumannii are organisms frequently found in the environment. This bacterium causes several types of infections, such as bacteremia, pneumonia and urinary tract infection [1]. Carbapenem resistance in A. baumannii is more often caused by the production of ...

Pattern Of Polymicrobial Isolates And Antimicrobial Susceptibility From Blood

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Shabbir, S.; Jamil, S.; Hafiz, S.

2016-01-01

Objective: To determine the pattern of polymicrobial isolates in blood cultures and antimicrobial susceptibility in a tertiary care hospital of Karachi. Study Design: Cross-sectional study. Place and Duration of Study: Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan, from September to November 2014. Methodology: Blood culture samples were received from patients, which were processed by BACTEC 9240 system (Becton Dickinson). All positive blood samples were further analyzed. Susceptibility to antimicrobial agents was determined according to the Clinical and Laboratory Standards Institute (CLSI) criteria of the year. Identification of growth was based on Gram staining, colony morphology and appropriate biochemical tests. Antibiotic susceptibility was done as per Clinical and Laboratory Standards Institute (CLSI) recommendations. Results: Out of the 7251 samples submitted, 2931 (40.42 percent) were positive for growth, 2389 (81.5 percent) samples were monomicrobial, whereas 542 (18.5 percent) samples were polymicrobial. Among the polymicrobial isolates, 468 (86.34 percent) blood culture samples yielded two, 66 (12.17 percent) yielded three, and 8 (1.47 percent) yielded four organisms. Gram positive isolates were 281 (51.84 percent) and Gram negative were 261 (48.15 percent). The most frequent isolates in polymicrobial blood stream infection were Acinetobacterspp. (51/542, 9.4 percent) and Coagulase negative Staphylococcus(84/542, 15.5 percent), respectively. Staphylococcus aureus isolates, which were resistant to Methicillin, accounted for 24.65 percent. Third generation Cephalosporins resistance in Klebsiella spp. and Eschericia (E.) coli was found to be 63.6 percent and 58 percent, respectively. Carbapenem resistance was seen in 5.9 percent of Pseudomonas aeruginosa and 17.6 percent Acinetobacter spp. Conclusion: Gram positive bacteria were more commonly involved in polymicrobial blood stream infections with Coagulase negative Staphylococcus

Mutations in the β-Subunit of the RNA Polymerase Impair the Surface-Associated Motility and Virulence of Acinetobacter baumannii.

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Pérez-Varela, María; Corral, Jordi; Vallejo, Juan Andrés; Rumbo-Feal, Soraya; Bou, Germán; Aranda, Jesús; Barbé, Jordi

2017-08-01

Acinetobacter baumannii is a major cause of antibiotic-resistant nosocomial infections worldwide. In this study, several rifampin-resistant spontaneous mutants obtained from the A. baumannii ATCC 17978 strain that differed in their point mutations in the rpoB gene, encoding the β-subunit of the RNA polymerase, were isolated. All the mutants harboring amino acid substitutions in position 522 or 540 of the RpoB protein were impaired in surface-associated motility and had attenuated virulence in the fertility model of Caenorhabditis elegans The transcriptional profile of these mutants included six downregulated genes encoding proteins homologous to transporters and metabolic enzymes widespread among A. baumannii clinical isolates. The construction of knockout mutants in each of the six downregulated genes revealed a significant reduction in the surface-associated motility and virulence of four of them in the A. baumannii ATCC 17978 strain, as well as in the virulent clinical isolate MAR002. Taken together, our results provide strong evidence of the connection between motility and virulence in this multiresistant nosocomial pathogen. Copyright © 2017 American Society for Microbiology.

Diversity of biosurfactant producing microorganisms isolated from soils contaminated with diesel oil.

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Menezes Bento, Fátima; de Oliveira Camargo, Flavio A; Okeke, Benedict C; Frankenberger, William T

2005-01-01

Biosurfactant production is a desirable property of hydrocarbon-degrading microorganisms (HDM). We characterized biosurfactant producing microbial populations from a Long Beach soil, California (USA) and a Hong Kong soil (China), contaminated with diesel oil. A total of 33 hydrocarbon-utilizing microorganisms were isolated from the soils. Twelve isolates and three defined consortia were tested for biosurfactant production and emulsification activity. The highest reduction of surface tension was achieved with a consortium of L1, L2 and L3 isolates from a Long Beach soil (41.4mN m(-1)). Isolate L1 (Acinetobacter junii) displayed the highest reduction of surface tension (46.5 mN m(-1)). The emulsifying capacity evaluated by the E24 emulsification index was highest in the culture of isolate L5 (74%). No substantial emulsification was achieved with the cell-free extracts, indicating that the emulsifying activity was not extracellular. Based on surface tension and the E24 index results, isolates F1, F2, F3, F4, L1, L2, L3 and L4 were identified by 16S rRNA gene sequencing as Bacillus cereus, Bacillus sphaericus, B. fusiformis, Acinetobacter junii, a non-cultured bacterium, Pseudomonas sp. and B. pumilus, respectively. Cluster analyses of 16S rRNA gene sequences of the bacterial isolates revealed 70% similarity amongst hydrocarbon-degrading bacterial community present in both soils. Five isolates (isolates F1, F2, F3, F4 and L4) belong to the Firmicutes order, two isolates (L1 and L3) belong to the Proteobacteria order and one isolate (L2) is an Actinomyces sp. Simpson's index (1 - D) and the Shannon-Weaver index (H) revealed more diversity of HDM in the Hong Kong soil, while evenness (E) and the equitability (J) data indicated that there was not a dominant population. Bacterial isolates displaying substantial potential for production of biosurfactants can be applied in the bioremediation of soils contaminated with petroleum hydrocarbons.

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

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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.

CRISPR-cas Subtype I-Fb in Acinetobacter baumannii: Evolution and Utilization for Strain Subtyping

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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. PMID:25706932

Molecular epidemiology of carbapenem non-susceptible Acinetobacter nosocomialis in a medical center in Taiwan.

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Yang, Ya-Sung; Lee, Yi-Tzu; Wang, Yung-Chih; Chiu, Chun-Hsiang; Kuo, Shu-Chen; Sun, Jun-Ren; Yin, Ti; Chen, Te-Li; Lin, Jung-Chung; Fung, Chang-Phone; Chang, Feng-Yee

2015-04-01

The mechanism by which carbapenem non-susceptible Acinetobacter nosocomialis (CNSAN) is disseminated is rarely described in the literature. In this study, we delineated the molecular epidemiology of CNSAN isolated from patients in a medical center in Taiwan. Fifty-four non-duplicate bloodstream isolates of CNSAN were collected at the Taipei Veterans General Hospital between 2001 and 2007. Pulsed-field gel electrophoresis (PFGE) was performed to determine their clonal relationship. Carbapenem-resistance genes and associated genetic structures were detected by polymerase chain reaction (PCR) mapping. Southern hybridization was performed to determine the plasmid location of carbapenem-resistance genes. Transmissibility of these genes to Acinetobacterbaumannii was demonstrated by conjugation tests. The overall carbapenem non-susceptibility rate among A. nosocomialis isolates during the study period was 21.6% (54/250). PFGE revealed three major pulsotypes: H (n=23), I (n=10), and K (n=8). The most common carbapenem-resistance gene was blaOXA-58 (43/54, 79.6%), containing an upstream insertion sequence IS1006 and a truncated ISAba3 (IS1006-ΔISAba3-like-blaOXA-58). All isolates belonging to the pulsotypes H, I, and K carried plasmid located IS1006-ΔISAba3-like-blaOXA-58. A common plasmid carrying ISAba1-blaOXA-82 was found in six isolates, which belonged to five pulsotypes. A type 1 integron that carried blaIMP-1 was detected in different plasmids of seven isolates, which belonged to five pulsotypes. Plasmids carrying these carbapenem-resistant determinants were transmissible from A. nosocomialis to A. baumannii via conjugation. In this medical center, CNSAN mainly emerged through clonal dissemination; propagation of plasmids and integrons carrying carbapenem-resistant determinants played a minor role. This study showed that plasmids carrying carbapenem-resistant determinants are transmissible from A. nosocomialis to A. baumannii. Copyright © 2015 Elsevier B.V. All

Acinetobacter baumannii in Localised Cutaneous Mycobacteriosis in Falcons

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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.

Place of Colistin-Rifampicin Association in the Treatment of Multidrug-Resistant Acinetobacter Baumannii Meningitis: A Case Study

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Dahraoui Souhail

2016-01-01

Full Text Available Treatment of Acinetobacter baumannii meningitis is an important challenge due to the accumulation of resistance of this bacteria and low meningeal diffusion of several antimicrobial requiring use of an antimicrobial effective combination to eradicate these species. We report a case of Acinetobacter baumannii multidrug-resistant nosocomial meningitis which was successfully treated with intravenous and intrathecal colistin associated with rifampicin.

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

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Anton Y Peleg

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

The Success of Acinetobacter Species; Genetic, Metabolic and Virulence Attributes

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Peleg, Anton Y.; de Breij, Anna; Adams, Mark D.; Cerqueira, Gustavo M.; Mocali, Stefano; Galardini, Marco; Nibbering, Peter H.; Earl, Ashlee M.; Ward, Doyle V.; Paterson, David L.; Seifert, Harald; Dijkshoorn, Lenie

2012-01-01

An understanding of why certain Acinetobacter species are more successful in causing nosocomial infections, transmission and epidemic spread in healthcare institutions compared with other species is lacking. We used genomic, phenotypic and virulence studies to identify differences between Acinetobacter species. Fourteen strains representing nine species were examined. Genomic analysis of six strains showed that the A. baumannii core genome contains many genes important for diverse metabolism and survival in the host. Most of the A. baumannii core genes were also present in one or more of the less clinically successful species. In contrast, when the accessory genome of an individual A. baumannii strain was compared to a strain of a less successful species (A. calcoaceticus RUH2202), many operons with putative virulence function were found to be present only in the A. baumannii strain, including the csu operon, the acinetobactin chromosomal cluster, and bacterial defence mechanisms. Phenotype microarray analysis showed that compared to A. calcoaceticus (RUH2202), A. baumannii ATCC 19606T was able to utilise nitrogen sources more effectively and was more tolerant to pH, osmotic and antimicrobial stress. Virulence differences were also observed, with A. baumannii ATCC 19606T, A. pittii SH024, and A. nosocomialis RUH2624 persisting and forming larger biofilms on human skin than A. calcoaceticus. A. baumannii ATCC 19606T and A. pittii SH024 were also able to survive in a murine thigh infection model, whereas the other two species were eradicated. The current study provides important insights into the elucidation of differences in clinical relevance among Acinetobacter species. PMID:23144699

Antibiotic resistance of microbial contaminations isolated from husbandry animals and foodstuffs

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Lukáš Hleba

2014-05-01

Full Text Available In this paper the antibiotic resistance of microbial contaminations isolated from husbandry animals and foodstuffs were investigated. Microorganisms isolated from animals and foodstuffs were contaminations of selective media as MacConkey agar for Enterobacteriaceae genera and MRS agar for lactobacilli strains. Microorganisms were isolated and puryfied by agar four ways streak plate method. Identification of isolated microorganisms was done by mass-spectrometry method in MALDI-TOF MS Biotyper. For investigation of antibiotic resistance disc diffusion method by EUCAST was used. In this study Gram-negative and Gram-positive bacteria were identified. The most resistant or multi-resistant bacteria as Pseudomonas aeruginosa, Acinetobacter lwoffi, Lysinibacillus sphaericus, Staphylococcus aureus and Staphylococcus epidermis were determined. Other identified microorganisms were resistant to one antibiotic or not at all.

Dissemination of imipenem-resistant Acinetobacter baumannii with new plasmid-borne bla(OXA-72) in Taiwan.

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Kuo, Shu-Chen; Yang, Su-Pen; Lee, Yi-Tzu; Chuang, Han-Chuan; Chen, Chien-Pei; Chang, Chi-Ling; Chen, Te-Li; Lu, Po-Liang; Hsueh, Po-Ren; Fung, Chang-Phone

2013-07-13

The systemic surveillance of imipenem-resistant Acinetobacter baumannii (IRAB) from multicenters in Taiwan revealed the emergence of isolates with bla(OXA-72). This study described their genetic makeup, mechanism of spread, and contribution to carbapenem resistance. Two hundred and ninety-one non-repetitive isolates of A. baumannii were collected from 10 teaching hospitals from different geographical regions in Taiwan from June 2007 to September 2007. Minimal inhibitory concentrations (MICs) were determined by agar dilution. Clonality was determined by pulsed-field gel electrophoresis. Plasmid was extracted and digested by restriction enzymes, and subsequently analyzed by electrophoresis and Southern blot for bla(OXA-72). The flanking regions of bla(OXA-72) were determined by inverse PCR. The contribution of bla(OXA-72) to imipenem MIC was determined by transforming plasmids carrying bla(OXA-72) into imipenem-susceptible A. baumannii. Among 142 IRAB in Taiwan, 27 harbored bla(OXA-72); 22 originated from Southern Taiwan, 5 from Central Taiwan, and none from Northern Taiwan. There were two major clones. The bla(OXA-72) was identified in the plasmids of all isolates. Two genetic structures flanking plasmid-borne bla(OXA-72) were identified and shared identical sequences in certain regions; the one described in previous literature was present in only one isolate, and the new one was present in the remaining isolates. Introduction of bla(OXA-72) resulted in an increase of imipenem MIC in the transformants. The overexpression of bla(OXA-72) mRNA in response to imipenem further supported the contribution of bla(OXA-72). In conclusion, isolates with new plasmid-borne blaOXA-72 were found to be disseminated successfully in Southern Taiwan. The spread of the resistance gene depended on clonal spread and dissemination of a new plasmid. Bla(OXA-72) in these isolates directly led to their imipenem-resistance.

Standardization and interlaboratory reproducibility assessment of pulsed-field gel electrophoresis-generated fingerprints of Acinetobacter baumannii.

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Seifert, Harald; Dolzani, Lucilla; Bressan, Raffaela; van der Reijden, Tanny; van Strijen, Beppie; Stefanik, Danuta; Heersma, Herre; Dijkshoorn, Lenie

2005-09-01

A standard procedure for pulsed-field gel electrophoresis (PFGE) of macrorestriction fragments of Acinetobacter baumannii was set up and validated for its interlaboratory reproducibility and its potential for use in the construction of an Internet-based database for international monitoring of epidemic strains. The PFGE fingerprints of strains were generated at three different laboratories with ApaI as the restriction enzyme and by a rigorously standardized procedure. The results were analyzed at the respective laboratories and also centrally at a national reference institute. In the first phase of the study, 20 A. baumannii strains, including 3 isolates each from three well-characterized hospital outbreaks and 11 sporadic strains, were distributed blindly to the participating laboratories. The local groupings of the isolates in each participating laboratory were identical and allowed the identification of the epidemiologically related isolates as belonging to three clusters and identified all unrelated strains as distinct. Central pattern analysis by using the band-based Dice coefficient and the unweighted pair group method with mathematical averaging as the clustering algorithm showed 95% matching of the outbreak strains processed at each local laboratory and 87% matching of the corresponding strains if they were processed at different laboratories. In the second phase of the study, 30 A. baumannii isolates representing 10 hospital outbreaks from different parts of Europe (3 isolates per outbreak) were blindly distributed to the three laboratories, so that each laboratory investigated 10 epidemiologically independent outbreak isolates. Central computer-assisted cluster analysis correctly identified the isolates according to their corresponding outbreak at an 87% clustering threshold. In conclusion, the standard procedure enabled us to generate PFGE fingerprints of epidemiologically related A. baumannii strains at different locations with sufficient

Screening and Evaluation of the Bioremediation Potential of Cu/Zn-resistant, Autochthonous Acinetobacter sp. FQ-44 from Sonchus oleraceus L.

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Qing Fang

2016-09-01

Full Text Available The quest for new, promising and indigenous plant growth-promoting rhizobacteria and a deeper understanding of their relationship with plants are important considerations in the improvement of phytoremediation. This study focuses on the screening of plant beneficial Cu/Zn-resistant strains and assessment of their bioremediation potential (metal solubilization/tolerance/biosorption and effects on growth of Brassica napus seedlings to identify suitable rhizobacteria and examine their roles in microbes-assisted phytoremediation. Sixty Cu/Zn-resistant rhizobacteria were initially isolated from Sonchus oleraceus grown at a multi-metal-polluted site in Shanghai, China. From these strains, 19 isolates that were all resistant to 300 mg·L-1 Cu as well as 300 mg·L-1 Zn, and could simultaneously grow on Dworkin-Foster salt minimal medium containing 1-aminocyclopropane-1-carboxylic acid were preliminarily selected. Of those 19 isolates, 10 isolates with superior plant growth-promoting properties (indole-3-acetic acid production, siderophore production and insoluble phosphate solubilization were secondly chosen and further evaluated to identify those with the highest bioremediation potential and capacity for bioaugmentation. Strain S44, identified as Acinetobacter sp. FQ-44 based on 16S rDNA sequencing, was specifically chosen as the most favorable strain owing to its strong capabilities to (1 promote the growth of rape seedlings (significantly increased root length, shoot length and fresh weight by 92.60%, 31.00% and 41.96%, respectively under gnotobiotic conditions; (2 tolerate up to 1000 mg·L-1 Cu and 800 mg·L-1 Zn; (3 mobilize the highest concentrations of water-soluble Cu, Zn, Pb and Fe (16.99, 0.98, 0.08 and 3.03 mg·L-1, respectively; and (4 adsorb the greatest quantities of Cu and Zn (7.53 and 6.61 mg·g-1 dry cell, respectively. Our findings suggest that Acinetobacter sp. FQ-44 could be exploited for bacteria-assisted phytoextraction. Moreover

Degradation of polyisoprene rubber by newly isolated Bacillus sp. AF-666 from soil.

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Shah, A A; Hasan, F; Shah, Z; Mutiullah; Hameed, A

2012-01-01

Various microorganisms were screened for their ability to degrade polyisoprene rubber (natural rubber latex gloves). Strain AF-666, newly isolated from a soil sample, was selected as the best strain having the ability to grow on polyisoprene containing plates. The strain identified as Bacillus sp. AF-666, was found to degrade polyisoprene rubber, both on basal agar plates (latex overlay) as well as in liquid medium. Qualitative analysis of degradation was done through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy SEM showed changes in surface morphology, like appearance of pits and cracks, and marked difference in transmittance spectra of test and control due to changes in the functional groups, was detected through FTIR. CO2 evolution as a result of rubber degradation, was calculated gravimetrically by Sturm Test. About 4.43 g/1 of CO2 was produced in case of test, whereas, 1.57 g/1 in case of control. The viable number of cells (CFU/ml) was also higher in test than in control. Present study may provide an opportunity for further studies on the applications of biotechnological processes as a tool for rubber waste management.

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

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Fabiola G Zuno-Floriano

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

Coexistence of Extended Spectrum Beta-Lactamases, AmpC Beta-Lactamases and Metallo-Beta-Lactamases in Acinetobacter baumannii from burns patients: a report from a tertiary care centre of India

OpenAIRE

Gupta, V.; Garg, R.; Garg, S.; Chander, J.; Attri, A.K.

2013-01-01

Multidrug-resistant Acinetobacter baumanii is a major pathogen encountered in pyogenic infections, especially from burns patients in hospital settings. Often there is also coexistence of multiple beta-lactamase enzymes responsible for beta-lactam resistance in a single isolate, which further complicates treatment options. We conducted a study on burn wound pus samples obtained from the burns unit of our hospital. Phenotypic tests were used to determine the Extended Spectrum Beta-Lactamase, Am...

Westinghouse Hanford Company plan for certifying newly generated contact-handled transuranic waste for emplacement in the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Lipinski, R.M.; Sheehan, J.S.

1992-07-01

Westinghouse Hanford Company (Westinghouse Hanford) currently manages an interim storage site for Westinghouse Hanford and non-Westinghouse Hanford-generated transuranic (TRU) waste and operates TRU waste generating facilities within the Hanford Site in Washington State. Approval has been received from the Waste Acceptance Criteria Certification Committee (WACCC) and Westinghouse Hanford TRU waste generating facilities to certify newly generated contact-handled TRU (CH-TRU) solid waste to meet the Waste Acceptance Criteria (WAC). This document describes the plan for certifying newly generated CH-TRU solid waste to meet the WAC requirements for storage at the Waste Isolation Pilot Plant (WIPP) site. Attached to this document are facility-specific certification plans for the Westinghouse Hanford TRU waste generators that have received WACCC approval. The certification plans describe operations that generate CH-TRU solid waste and the specific procedures by which these wastes will be certified and segregated from uncertified wastes at the generating facilities. All newly generated CH-TRU solid waste is being transferred to the Transuranic Storage and Assay Facility (TRUSAF) and/or a controlled storage facility. These facilities will store the waste until the certified TRU waste can be sent to the WIPP site and the non-certified TRU waste can be sent to the Waste Receiving and Processing Facility. All non-certifiable TRU waste will be segregated and clearly identified

Bacillus subtilis from Soybean Food Shows Antimicrobial Activity for Multidrug-Resistant Acinetobacter baumannii by Affecting the adeS Gene.

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Wang, Tieshan; Su, Jianrong

2016-12-28

Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii . Nineteen multidrug-resistant A. baumannii strains were clinifcally isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii . The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis . Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

Characteristics of plasmids in multi-drug-resistant Enterobacteriaceae isolated during prospective surveillance of a newly opened hospital in Iraq.

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Xiao-Zhe Huang

Full Text Available BACKGROUND: Gram-negative multidrug-resistant (MDR bacteria are major causes of nosocomial infections, and antibiotic resistance in these organisms is often plasmid mediated. Data are scarce pertaining to molecular mechanisms of antibiotic resistance in resource constrained areas such as Iraq. METHODOLOGY/PRINCIPAL FINDINGS: In this study, all MDR Enterobacteriaceae (n = 38 and randomly selected non-MDR counterparts (n = 41 isolated from patients, healthcare workers and environmental surfaces in a newly opened hospital in Iraq were investigated to characterize plasmids found in these isolates and determine their contribution to antibiotic resistance. Our results demonstrated that MDR E. coli and K. pneumoniae isolates harbored significantly more (≥ 3 plasmids compared to their non-MDR counterparts, which carried ≤ 2 plasmids (p<0.01. Various large plasmids (~52 to 100 kb from representative isolates were confirmed to contain multiple resistance genes by DNA microarray analysis. Aminoglycoside (acc, aadA, aph, strA/B, and ksgA, β-lactam (bla(TEM1, bla(AMPC, bla(CTX-M-15, bla(OXA-1, bla(VIM-2 and bla(SHV, sulfamethoxazole/trimethoprim (sul/dfr, tetracycline (tet and chloramphenicol (cat resistance genes were detected on these plasmids. Additionally, multiple plasmids carrying multiple antibiotic resistance genes were found in the same host strain. Genetic transfer-associated genes were identified on the plasmids from both MDR and non-MDR isolates. Seven plasmid replicon types (FII, FIA, FIB, B/O, K, I1 and N were detected in the isolates, while globally disseminated IncA/C and IncHI1 plasmids were not detected in these isolates. CONCLUSIONS/SIGNIFICANCE: This is the first report of the characteristics of the plasmids found in Enterobacteriaceae isolated following the opening of a new hospital in Iraq. The information provided here furthers our understanding of the mechanisms of drug resistance in this specific region and their evolutionary

Isolation and characterization of antimicrobial compounds in plant extracts against multidrug-resistant Acinetobacter baumannii.

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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.

Molecular Analysis and Expression of bap Gene in Biofilm-Forming Multi-Drug-Resistant Acinetobacter baumannii

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Omid Azizi

2016-10-01

Full Text Available Background: Acinetobacter baumannii is commonly resistant to nearly all antibiotics due to presence of antibiotic resistance genes and biofilm formation. In this study we determined the presence of certain antibiotic-resistance genes associated with biofilm production and the influence of low iron concentration on expression of the biofilm-associated protein gene (bap in development of biofilm among multi-drug-resistant A. baumannii (MDRAB. Methods: Sixty-five MDRAB isolates from clinical samples were collected. Molecular typing was carried out by random amplified polymorphism DNA polymerase chain reaction (RAPD-PCR. Biofilm formation was assayed by the microtiter method. Results: The sequence of bap was determined and deposited in the GenBank database (accession no. KR080550.1. Expression of bap in the presence of low iron was analyzed by relative quantitative real time PCR (rqRT-PCR. Nearly half of the isolates belonged to RAPD-types A and B remaining were either small clusters or singleton. The results of biofilm formation revealed that 23 (35.4%, 18 (27.7%, 13 (20%, and 11 (16.9% of the isolates had strong, moderate, weak, and no biofilm activities, respectively. ompA and csuE genes were detected in all, while bap and blaPER-1 were detected in 43 (66% and 42 (64% of the isolates that showed strong and moderate biofilm activities (p ≤ 0.05, respectively. Analysis of bap expression by rqRT-PCR revealed five isolates with four-fold bap overexpression in the presence of low iron concentration (20 μM. Conclusion: The results suggest that bap overexpression may influence biofilm formation in presence of low iron concentration.

Ceftriaxone and ciprofloxacin restriction in an intensive care unit: less incidence of Acinetobacter spp. and improved susceptibility of Pseudomonas aeruginosa Restricción del uso de ceftriaxona y ciprofloxacino en una unidad de cuidados intensivos: menor incidencia de Acinetobacter spp. y mayor sensibilidad de Pseudomonas aeruginosa

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Julio César Medina Presentado

2011-12-01

Full Text Available OBJETIVO: To determine whether restricting the use of ceftriaxone and ciprofloxacin couldsignificantly reduce colonization and infection with resistant Gram-negative bacilli (r-GNB. METHODS: A two-phase prospective study (before/after design was conducted in an intensive care unit in two time periods (2004-2006. During phase 1, there was no antibiotic restriction. During phase 2, use of ceftriaxone or ciprofloxacin was restricted. RESULTS: Atotal of 200 patients were prospectively evaluated. In phase 2, the use of ceftriaxone was reduced by 93.6% (P = 0.0001 and that of ciprofloxacin by 65.1% (P = 0.041, accompanied by a 113.8% increase in use of ampicillin-sulbactam (P = 0.002.During phase 1, 48 GNB were isolated [37 r-GNB (77.1% and 11 non-r-GNB (22.9%], compared with a total of 64 during phase 2 [27 r-GNB (42.2% and 37 non-r-GNB (57.8%](P = 0.0002. Acinetobacter spp. was isolated 13 times during phase 1 and 3 times in phase 2 (P = 0.0018. The susceptibility of Pseudomonas aeruginosa to ciprofloxacin increased from 40.0% in phase 1 to 100.0% in phase 2 (P = 0.0108. CONCLUSIONS: Restriction of ceftriaxone and ciprofloxacin reduced colonization by Acinetobacter spp. and improved the susceptibility profile of P. aeruginosa.OBJETIVO: Determinar si la restricción del uso de ceftriaxona y ciprofloxacino reduce significativamente la colonización y la infección por bacilos gramnegativos resistentes. MÉTODOS: Se efectuó un estudio prospectivo de dos fases (diseño antes/después de la intervención en una unidad de cuidados intensivos en dos períodos sucesivos entre los años 2004 y 2006. Durante la fase 1, no hubo ninguna restricción de antibióticos. Durante la fase 2, se restringió el uso de ceftriaxona y ciprofloxacino. RESULTADOS: Se evaluó prospectivamente a 200 pacientes en total. En la fase 2, el uso de ceftriaxona se redujo en 93,6% (P = 0,0001 y el de ciprofloxacino en 65,1% (P = 0,041, lo que se acompañó de un aumento de 113,8% en

A new insight to adsorption and accumulation of high lead concentration by exopolymer and whole cells of lead-resistant bacterium Acinetobacter junii L. Pb1 isolated from coal mine dump.

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Kushwaha, Anamika; Rani, Radha; Kumar, Sanjay; Thomas, Tarence; David, Arun Alfred; Ahmed, Meraz

2017-04-01

A lead-resistant bacterial strain was isolated from coal mine dump and identified as Acinetobacter junii Pb1 on basis of 16S rRNA (ribosomal ribonucleic acid) gene sequencing. The minimum inhibitory concentration of lead for the strain was 16,000 mg l -1 and it showed antibiotic and multi metal resistance. In aqueous culture, at an initial lead (Pb(II)) concentration of 100 and 500 mg l -1 , lead adsorption and accumulation by the isolate was 100 and 60%, at pH 7 at 30 °C after 48 and 120 h, respectively. The two fractions of exopolysaccharide (EPS), loosely associated EPS (laEPS) and bound EPS (bEPS), and whole cells (devoid of EPS) showed high binding affinity towards Pb(II). The binding affinity of laEPS towards Pb(II) (1071 mg Pb g -1 ) was three times higher than that of bEPS (321.5 mg Pb g -1 ) and 6.5 times higher than that of whole cells (165 mg Pb g -1 ). The binding affinity of EPS and whole cells with Pb(II), reported in the current study, is considerably higher as compared to that reported in the literature, till date. SEM analysis, showed an increase in thickness of cells on exposure to Pb(II) and TEM analysis, revealed its accumulation (interior of cell) and its adsorption (with the external cell surface). The isolate was also found to be positive for indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase production which helps in promoting plant growth. Thus, this study provides a new understanding towards Pb(II) uptake by A. junii Pb1, highlighting its potential on the restoration of Pb(II) contaminated repositories.

An Increase of Abundance and Transcriptional Activity for Acinetobacter junii Post Wastewater Treatment

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Muhammad Raihan Jumat

2018-04-01

Full Text Available A membrane bioreactor (MBR-based wastewater treatment plant (WWTP in Saudi Arabia is assessed over a five-month period in 2015 and once in 2017 for bacterial diversity and transcriptional activity using metagenomics, metatranscriptomics and real time quantitative polymerase chain reaction (RT-qPCR. Acinetobacter spp. are shown to be enriched in the chlorinated effluent. Members of the Acinetobacter genus are the most abundant in the effluent and chlorinated effluent. At the species level, Acinetobacter junii have higher relative abundances post MBR and chlorination. RNA-seq analysis show that, in A. junii, 288 genes and 378 genes are significantly upregulated in the effluent and chlorinated effluent, respectively, with 98 genes being upregulated in both. RT-qPCR of samples in 2015 and 2017 confirm the upregulation observed in RNA-seq. Analysis of the 98 genes show that majority of the upregulated genes are involved in cellular repair and metabolism followed by resistance, virulence, and signaling. Additionally, two different subpopulations of A. junii are observed in the effluent and chlorinated effluent. The upregulation of cellular repair and metabolism genes, and the formation of different subpopulations of A. junii in both effluents provide insights into the mechanisms employed by A. junii to persist in the conditions of a WWTP.

An Increase of Abundance and Transcriptional Activity for Acinetobacter junii Post Wastewater Treatment

KAUST Repository

Jumat, Muhammad; Haroon, Muhammad; Aljassim, Nada I.; Cheng, Hong; Hong, Pei-Ying

2018-01-01

A membrane bioreactor (MBR)-based wastewater treatment plant (WWTP) in Saudi Arabia is assessed over a five-month period in 2015 and once in 2017 for bacterial diversity and transcriptional activity using metagenomics, metatranscriptomics and real time quantitative polymerase chain reaction (RT-qPCR). Acinetobacter spp. are shown to be enriched in the chlorinated effluent. Members of the Acinetobacter genus are the most abundant in the effluent and chlorinated effluent. At the species level, Acinetobacter junii have higher relative abundances post MBR and chlorination. RNA-seq analysis show that, in A. junii, 288 genes and 378 genes are significantly upregulated in the effluent and chlorinated effluent, respectively, with 98 genes being upregulated in both. RT-qPCR of samples in 2015 and 2017 confirm the upregulation observed in RNA-seq. Analysis of the 98 genes show that majority of the upregulated genes are involved in cellular repair and metabolism followed by resistance, virulence, and signaling. Additionally, two different subpopulations of A. junii are observed in the effluent and chlorinated effluent. The upregulation of cellular repair and metabolism genes, and the formation of different subpopulations of A. junii in both effluents provide insights into the mechanisms employed by A. junii to persist in the conditions of a WWTP.

An Increase of Abundance and Transcriptional Activity for Acinetobacter junii Post Wastewater Treatment

KAUST Repository

Jumat, Muhammad

2018-04-11

A membrane bioreactor (MBR)-based wastewater treatment plant (WWTP) in Saudi Arabia is assessed over a five-month period in 2015 and once in 2017 for bacterial diversity and transcriptional activity using metagenomics, metatranscriptomics and real time quantitative polymerase chain reaction (RT-qPCR). Acinetobacter spp. are shown to be enriched in the chlorinated effluent. Members of the Acinetobacter genus are the most abundant in the effluent and chlorinated effluent. At the species level, Acinetobacter junii have higher relative abundances post MBR and chlorination. RNA-seq analysis show that, in A. junii, 288 genes and 378 genes are significantly upregulated in the effluent and chlorinated effluent, respectively, with 98 genes being upregulated in both. RT-qPCR of samples in 2015 and 2017 confirm the upregulation observed in RNA-seq. Analysis of the 98 genes show that majority of the upregulated genes are involved in cellular repair and metabolism followed by resistance, virulence, and signaling. Additionally, two different subpopulations of A. junii are observed in the effluent and chlorinated effluent. The upregulation of cellular repair and metabolism genes, and the formation of different subpopulations of A. junii in both effluents provide insights into the mechanisms employed by A. junii to persist in the conditions of a WWTP.

Activity of levofloxacin in combination with colistin against Acinetobacter baumannii: In vitro and in a Galleria mellonella model

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Wenjuan Wei

2017-12-01

Full Text Available Background/Purpose: Treatment of Acinetobacter baumannii infections is challenging owing to widespread multidrug-resistant A. baumannii (MDR-AB and the lack of novel agents. Although recent data suggest that levofloxacin (LVX may have unique activity against MDR-AB in combination with colistin (CST, further preclinical work is needed. Methods: We used a A. baumannii type strain ATCC19606, a CST-resistant strain AB19606R, and two clinical isolates (GN0624 and GN1115 of MDR-AB to investigate the in vitro and in vivo efficacy of LVX–CST combination. Synergy studies were performed using the microtiter plate chequerboard assay and time–kill methodology. Inhibitory activity of antibiotics against biofilms and the mutant prevention concentrations were also studied in vitro. A simple invertebrate model (Galleria mellonella has been used to assess the in vivo activity of antimicrobial therapies. Results: The LVX–CST combination was bactericidal against the CST-susceptible clinical isolate (GN0624. In checkerboard assays, synergy (defined as a fractional inhibitory concentration index of < 0.5 was observed between CST and LVX in GN0624. The combination had antibiofilm properties on the preformed biofilms of four tested strains and could prevent the emergence of CST-resistant A. baumanni. Treatment of G. mellonella larvae infected with lethal doses of A. baumannii resulted in significantly enhanced survival rates when LVX was given with CST compared with CST treatment alone (p < 0.05. Conclusion: In summary, a synergistic or additive effect between CST and LVX was observed in vitro and in vivo against CST-susceptible A. baumannii strains, although not against CST-resistant ones. Keywords: Acinetobacter baumannii, antimicrobial synergy, invertebrate model, levofloxacin, polymyxins

Acquisition and clearance of multidrug resistant Acinetobacter baumannii on healthy young adults concurrently burned in a dust explosion in Taiwan: the implication for antimicrobial stewardship.

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Huang, Po-Yen; Shie, Shian-Sen; Ye, Jung-Jr; Lin, Shih-Pin; Liu, Tsui-Ping; Wu, Ting-Shu; Wu, Tsu-Lan; Chuang, Shiow-Shuh; Cheng, Ming-Huei; Hsieh, Yu-Chia; Huang, Ching-Tai

2017-08-30

Information is limited about the effect of restricted carbapenem use on clearance of multi-drug resistant Acinetobacter baumannii (MDRAB). We sought to determine the time effect of antibiotic exposure on multi-drug resistant Acinetobacter baumannii (MDRAB) acquisition and clearance. We conducted a retrospective observational study at the intensive care units of a tertiary medical center. Forty-two of a cohort of previously healthy young adults who were concurrently burned by a dust explosion was included. Cases consisted of those from whom MDRAB was isolated during hospitalization. Controls consisted of patients from whom MDRAB was not isolated in the same period. Use of antimicrobial agents was compared based on days of therapy per 1,000 patient-days (DOT/1,000PD). A 2-state Markov multi-state model was used to estimate the risk of acquisition and clearance of MDRAB. MDRAB was discovered in 9/42 (21.4%) individuals. The cases had significantly higher use of carbapenem (652 DOT/1,000PD vs. 385 DOT/1,000PD, P < 0.001) before MDRAB isolation. For the cases, clearance of MDRAB was associated with lower use of carbapenem (469 DOT/1,000PD vs. 708 DOT/1,000PD, P = 0.003) and higher use of non-carbapenem beta-lactam (612 DOT/1,000PD vs. 246 DOT/1,000PD, P <0.001). In multi-state model, each additional DOT of carbapenem increased the hazard of acquiring MDRAB (hazard ratio (HR), 1.08; 95% confidence interval (CI) 1.01-1.16) and each additional DOT of non-carbapenem beta-lactam increased the protection of clearing MDRAB (HR, 1.25; 95% CI 1.07-1.46). Both acquisition and clearance of MDRAB were related to antibiotic exposure in a homogeneous population. Our findings suggest that early discontinuation of carbapenem could be an effective measure in antibiotic stewardship for the control of MDRAB spreading.

Pattern of Bacterial Pathogens and Their Susceptibility Isolated from Surgical Site Infections at Selected Referral Hospitals, Addis Ababa, Ethiopia

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Walelign Dessie

2016-01-01

Full Text Available Background. The emergence of multidrug resistant bacterial pathogens in hospitals is becoming a challenge for surgeons to treat hospital acquired infections. Objective. To determine bacterial pathogens and drug susceptibility isolated from surgical site infections at St. Paul Specialized Hospital Millennium Medical College and Yekatit 12 Referral Hospital Medical College, Addis Ababa, Ethiopia. Methods. A cross-sectional study was conducted between October 2013 and March 2014 on 107 surgical site infected patients. Wound specimens were collected using sterile cotton swab and processed as per standard operative procedures in appropriate culture media; and susceptibility testing was done using Kirby-Bauer disc diffusion technique. The data were analyzed by using SPSS version 20. Result. From a total of 107 swabs collected, 90 (84.1% were culture positive and 104 organisms were isolated. E. coli (24 (23.1% was the most common organism isolated followed by multidrug resistant Acinetobacter species (23 (22.1%. More than 58 (75% of the Gram negative isolates showed multiple antibiotic resistance (resistance ≥ 5 drugs. Pan-antibiotic resistance was noted among 8 (34.8% Acinetobacter species and 3 (12.5% E. coli. This calls for abstinence from antibiotic abuse. Conclusion. Gram negative bacteria were the most important isolates accounting for 76 (73.1%. Ampicillin, amoxicillin, penicillin, cephazoline, and tetracycline showed resistance while gentamicin and ciprofloxacin were relatively effective antimicrobials.

The Genetic Analysis of an Acinetobacter johnsonii Clinical Strain Evidenced the Presence of Horizontal Genetic Transfer.

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Sabrina Montaña

Full Text Available Acinetobacter johnsonii rarely causes human infections. While most A. johnsonii isolates are susceptible to virtually all antibiotics, strains harboring a variety of β-lactamases have recently been described. An A. johnsonii Aj2199 clinical strain recovered from a hospital in Buenos Aires produces PER-2 and OXA-58. We decided to delve into its genome by obtaining the whole genome sequence of the Aj2199 strain. Genome comparison studies on Aj2199 revealed 240 unique genes and a close relation to strain WJ10621, isolated from the urine of a patient in China. Genomic analysis showed evidence of horizontal genetic transfer (HGT events. Forty-five insertion sequences and two intact prophages were found in addition to several resistance determinants such as blaPER-2, blaOXA-58, blaTEM-1, strA, strB, ereA, sul1, aacC2 and a new variant of blaOXA-211, called blaOXA-498. In particular, blaPER-2 and blaTEM-1 are present within the typical contexts previously described in the Enterobacteriaceae family. These results suggest that A. johnsonii actively acquires exogenous DNA from other bacterial species and concomitantly becomes a reservoir of resistance genes.

Current Trends of Drug Resistance Patterns of Acinetobacter baumannii Infection in Blood Transfusion-dependent Thalassemia Patients.

Science.gov (United States)

Almani, Suhail Ahmed; Naseer, Ali; Maheshwari, Sanjay Kumar; Maroof, Pir; Naseer, Raza; Khoharo, Haji Khan

2017-01-01

The present study aimed to evaluate the current trends of drug resistance patterns of Acinetobacter baumannii infection in blood transfusion-dependent thalassemia patients. This study was a cross sectional study, conducted at the Liaquat University of Medical and Health Sciences, Jamshoro/Hyderabad, Sindh, Pakistan from October 2014 to January 2016. Of 921 blood samples, A. baumannii strains were isolated from 100 blood samples. Blood samples were processed for the isolation, identification, and drugs sensitivity as per the Clinical and Laboratory Standards Institute. A. baumannii strains were identified by microbiological methods and Gram's staining. API 20 E kit (Biomeriuex, USA) was also used for identification. Data were analyzed on Statisti × 8.1 (USA). Mean ± standard deviation age was 11.5 ± 2.8 years. Nearly 70% were male and 30% were female ( P = 0.0001). Of 921 blood transfusion-dependent thalassemia patients, 100 (10.8%) patients showed growth of A. baumannii . Drug resistance was observed against the ceftazidime, cefixime, cefepime, imipenem, meropenem, amikacin, minocycline, tigecycline, and tazocin except for the colistin. The present study reports drug-resistant A. baumannii in blood transfusion-dependent thalassemia patients. National multicenter studies are recommended to estimate the size of the problem.

Comparison of the fuel oil biodegradation potential of hydrocarbon-assimilating microorganisms isolated from a temperate agricultural soil

International Nuclear Information System (INIS)

Chaineau, C.H.; Dupont, J.; Bury, E.; Oudot, J.; Morel, J.

1999-01-01

Strains of hydrocarbon-degrading microorganisms (bacteria and fungi) were isolated from an agricultural soil in France. In a field, a portion was treated with oily cuttings resulting from the drilling of an onshore well. The cuttings which were spread at the rate of 600 g HC m -2 contained 10% of fuel oil hydrocarbons (HC). Another part of the field was left untreated. Three months after HC spreading, HC adapted bacteria and fungi were isolated at different soil depths in the two plots and identified. The biodegradation potential of the isolated strains was monitored by measuring the degradation rate of total HC, saturated hydrocarbons, aromatic hydrocarbons and resins of the fuel. Bacteria of the genera Pseudomonas, Brevundimonas, Sphingomonas, Acinetobacter, Rhodococcus, Arthrobacter, Corynebacterium and fungi belonging to Aspergillus, Penicillium, Beauveria, Acremonium, Cladosporium, Fusarium, and Trichoderma were identified. The most active strains in the assimilation of saturates and aromatics were Arthrobacter sp., Sphingomonas spiritivorum, Acinetobacter baumanii, Beauveria alba and Penicillum simplicissimum. The biodegradation potential of the hydrocarbon utilizing microorganisms isolated from polluted or unpolluted soils were similar. In laboratory pure cultures, saturated HC were more degraded than aromatic HC, whereas resins were resistant to microbial attack. On an average, individual bacterial strains were more active than fungi in HC biodegradation. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Butyric acid production from red algae by a newly isolated Clostridium sp. S1.

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Lee, Kyung Min; Choi, Okkyoung; Kim, Ki-Yeon; Woo, Han Min; Kim, Yunje; Han, Sung Ok; Sang, Byoung-In; Um, Youngsoon

2015-09-01

To produce butyric acid from red algae such as Gelidium amansii in which galactose is a main carbohydrate, microorganisms utilizing galactose and tolerating inhibitors in hydrolysis including levulinic acid and 5-hydroxymethylfurfural (HMF) are required. A newly isolated bacterium, Clostridium sp. S1 produced butyric acid not only from galactose as the sole carbon source but also from a mixture of galactose and glucose through simultaneous utilization. Notably, Clostridium sp. S1 produced butyric acid and a small amount of acetic acid with the butyrate:acetate ratio of 45.4:1 and it even converted acetate to butyric acid. Clostridium sp. S1 tolerated 0.5-2 g levulinic acid/l and recovered from HMF inhibition at 0.6-2.5 g/l, resulting in 85-92% butyric acid concentration of the control culture. When acid-pretreated G. amansii hydrolysate was used, Clostridium sp. S1 produced 4.83 g butyric acid/l from 10 g galactose/l and 1 g glucose/l. Clostridium sp. S1 produces butyric acid from red algae due to its characteristics in sugar utilization and tolerance to inhibitors, demonstrating its advantage as a red algae-utilizing microorganism.

High resistance rate against 15 different antibiotics in aerobic gram-negative bacteria isolates of cardiology intensive care unit patients

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Küçükates E

2002-01-01

Full Text Available Aerobic gram negative bacteria were isolated and examined microbiologically from various clinical samples of 602 patients hospitalized between January 1997 and December 2000 in surgical and coronary intensive care units (ICUs. A total of 827 isolates were obtained from 602 patients. The majority of microorganisms were isolated from the respiratory tract (50.3% and blood (39.9%. Pseudomonas spp. were the most frequently isolated gram negative species (32.7%, followed by Acinetobacter spp. (24.0% and Klebsiella pneumoniae (19.4%. High resistance rates to all antibiotics studied were observed. Imipenem and meropenem were the most effective antibiotics against gram negatives.

A newly isolated probiotic Enterococcus faecalis strain from vagina microbiota enhances apoptosis of human cancer cells.

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Nami, Y; Abdullah, N; Haghshenas, B; Radiah, D; Rosli, R; Yari Khosroushahi, A

2014-08-01

This study aimed to describe probiotic properties and bio-therapeutic effects of newly isolated Enterococcus faecalis from the human vaginal tract. The Enterococcus faecalis strain was originally isolated from the vaginal microbiota of Iranian women and was molecularly identified using 16SrDNA gene sequencing. Some biochemical methodologies were preliminarily used to characterize the probiotic potential of Ent. faecalis, including antibiotic susceptibility, antimicrobial activity, as well as acid and bile resistance. The bio-therapeutic effects of this strain's secreted metabolites on four human cancer cell lines (AGS, HeLa, MCF-7 and HT-29) and one normal cell line (HUVEC) were evaluated by cytotoxicity assay and apoptosis scrutiny. The characterization results demonstrated into the isolated bacteria strain revealed probiotic properties, such as antibiotic susceptibility, antimicrobial activity and resistance under conditions similar to those in the gastrointestinal tract. Results of bio-therapeutic efficacy assessments illustrated acceptable apoptotic effects on four human cancer cell lines and negligible side effects on assayed normal cell line. Our findings revealed that the apoptotic effect of secreted metabolites mainly depended on proteins secreted by Ent. faecalis on different cancer cells. These proteins can induce the apoptosis of cancer cells. The metabolites produced by this vaginal Ent. faecalis strain can be used as alternative pharmaceutical compounds with promising therapeutic indices because they are not cytotoxic to normal mammalian cells. Accordingly, the physicochemical, structural and functional properties of the secreted anticancer substances should be further investigated before using them as anticancer therapeutics. This study aim to screen total bacterial secreted metabolites as a wealthy source to find the new active compounds to introduce as anticancer therapeutics in the future. © 2014 The Society for Applied Microbiology.

Molecular and Morphological Characterization of Fasciola spp. Isolated from Different Host Species in a Newly Emerging Focus of Human Fascioliasis in Iran

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Shafiei, Reza; Sarkari, Bahador; Sadjjadi, Seyed Mahmuod; Mowlavi, Gholam Reza; Moshfe, Abdolali

2014-01-01

The current study aimed to find out the morphometric and genotypic divergences of the flukes isolated from different hosts in a newly emerging focus of human fascioliasis in Iran. Adult Fasciola spp. were collected from 34 cattle, 13 sheep, and 11 goats from Kohgiluyeh and Boyer-Ahmad province, southwest of Iran. Genomic DNA was extracted from the flukes and PCR-RFLP was used to characterize the isolates. The ITS1, ITS2, and mitochondrial genes (mtDNA) of NDI and COI from individual liver flukes were amplified and the amplicons were sequenced. Genetic variation within and between the species was evaluated by comparing the sequences. Moreover, morphometric characteristics of flukes were measured through a computer image analysis system. Based on RFLP profile, from the total of 58 isolates, 41 isolates (from cattle, sheep, and goat) were identified as Fasciola hepatica, while 17 isolates from cattle were identified as Fasciola gigantica. Comparison of the ITS1 and ITS2 sequences showed six and seven single-base substitutions, resulting in segregation of the specimens into two different genotypes. The sequences of COI markers showed seven DNA polymorphic sites for F. hepatica and 35 DNA polymorphic sites for F. gigantica. Morphological diversity of the two species was observed in linear, ratios, and areas measurements. The findings have implications for studying the population genetics, epidemiology, and control of the disease. PMID:25018891

Molecular and Morphological Characterization of Fasciola spp. Isolated from Different Host Species in a Newly Emerging Focus of Human Fascioliasis in Iran

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Reza Shafiei

2014-01-01

Full Text Available The current study aimed to find out the morphometric and genotypic divergences of the flukes isolated from different hosts in a newly emerging focus of human fascioliasis in Iran. Adult Fasciola spp. were collected from 34 cattle, 13 sheep, and 11 goats from Kohgiluyeh and Boyer-Ahmad province, southwest of Iran. Genomic DNA was extracted from the flukes and PCR-RFLP was used to characterize the isolates. The ITS1, ITS2, and mitochondrial genes (mtDNA of NDI and COI from individual liver flukes were amplified and the amplicons were sequenced. Genetic variation within and between the species was evaluated by comparing the sequences. Moreover, morphometric characteristics of flukes were measured through a computer image analysis system. Based on RFLP profile, from the total of 58 isolates, 41 isolates (from cattle, sheep, and goat were identified as Fasciola hepatica, while 17 isolates from cattle were identified as Fasciola gigantica. Comparison of the ITS1 and ITS2 sequences showed six and seven single-base substitutions, resulting in segregation of the specimens into two different genotypes. The sequences of COI markers showed seven DNA polymorphic sites for F. hepatica and 35 DNA polymorphic sites for F. gigantica. Morphological diversity of the two species was observed in linear, ratios, and areas measurements. The findings have implications for studying the population genetics, epidemiology, and control of the disease.

Infecção cutânea rara por Acinetobacter baumannii em imunocompetente: relato de um caso Rare cutaneous infection by Acinetobacter baumannii in an immunocompetent patient: a case report

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Pablo Vitoriano Cirino

2008-08-01

Full Text Available O Acinetobacter baumanni é patógeno oportunista antigamente considerado de baixa virulência. Atualmente está envolvido em processos infecciosos que acometem pacientes imunocomprometidos,grandes queimados e pacientes em unidades de terapia intensiva que fazem uso de ventilação mecânica. Esse relato de caso chama atenção para infecção cutânea rara por essa bactéria em paciente imunocompetente.Acinetobacter baumannii is an oportunistic pathogen that used to be considered as having low virulence; however, it is currently known to be involved in infectious processes in patients with immunosuppression, large burns and those under mechanical ventilation in intensive care units. This case report emphasizes the possibility of cutaneous infection by A. baumanni in immunocompetent patients.

Metabolism of isoeugenol via isoeugenol-diol by a newly isolated strain of Bacillus subtilis HS8.

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Zhang, Yongmei; Xu, Ping; Han, Shuai; Yan, Haiqin; Ma, Cuiqing

2006-12-01

A bacterium designated as HS8 was newly isolated from soil based on its ability to degrade isoeugenol. The strain was identified as Bacillus subtilis according to its 16S rDNA sequence analysis and biochemical characteristics. The metabolic pathway for the degradation of isoeugenol was examined. Isoeugenol-diol, for the first time, was detected as an intermediate from isoeugenol to vanillin by a bacterial strain. Isoeugenol was converted to vanillin via isoeugenol-diol, and vanillin was then metabolized via vanillic acid to guaiacol by strain HS8. These metabolites, vanillin, vanillic acid, and guaiacol, are all valuable aromatic compounds in flavor production. At the same time, the bipolymerization of isoeugenol was observed, which produced dehydrodiisoeugenol and decreased the vanillin yield. High level of vanillic acid decarboxylase activity was detected in cell-free extract. These findings provided a detailed profile of isoeugenol metabolism by a B. subtilis strain for the first time, which would improve the production of valuable aromatic compounds by biotechnology.

The KL24 gene cluster and a genomic island encoding a Wzy polymerase contribute genes needed for synthesis of the K24 capsular polysaccharide by the multiply antibiotic resistant Acinetobacter baumannii isolate RCH51.

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Kenyon, Johanna J; Kasimova, Anastasiya A; Shneider, Mikhail M; Shashkov, Alexander S; Arbatsky, Nikolay P; Popova, Anastasiya V; Miroshnikov, Konstantin A; Hall, Ruth M; Knirel, Yuriy A

2017-03-01

The whole-genome sequence of the multiply antibiotic resistant Acinetobacter baumannii isolate RCH51 belonging to sequence type ST103 (Institut Pasteur scheme) revealed that the set of genes at the capsule locus, KL24, includes four genes predicted to direct the synthesis of 3-acetamido-3,6-dideoxy-d-galactose (d-Fuc3NAc), and this sugar was found in the capsular polysaccharide (CPS). One of these genes, fdtE, encodes a novel bifunctional protein with an N-terminal FdtA 3,4-ketoisomerase domain and a C-terminal acetyltransferase domain. KL24 lacks a gene encoding a Wzy polymerase to link the oligosaccharide K units to form the CPS found associated with isolate RCH51, and a wzy gene was found in a small genomic island (GI) near the cpn60 gene. This GI is in precisely the same location as another GI carrying wzy and atr genes recently found in several A. baumannii isolates, but it does not otherwise resemble it. The CPS isolated from RCH51, studied by sugar analysis and 1D and 2D 1H and 13C NMR spectroscopy, revealed that the K unit has a branched pentasaccharide structure made up of Gal, GalNAc and GlcNAc residues with d-Fuc3NAc as a side branch, and the K units are linked via a β-d-GlcpNAc-(1→3)-β-d-Galp linkage formed by the Wzy encoded by the GI. The functions of the glycosyltransferases encoded by KL24 were assigned to formation of specific bonds. A correspondence between the order of the genes in KL24 and other KL and the order of the linkages they form was noted, and this may be useful in future predictions of glycosyltransferase specificities.

Metabolic fingerprinting of bacterial strains isolated from northern areas of Pakistan

International Nuclear Information System (INIS)

Zaheer, A.; Latif, Z.

2017-01-01

The diversity of Plant Growth Promoting Rhizobacteria (PGPR) in the rhizosphere plays a key role in the maintenance of sustainable agricultural system. In this study, samples were obtained from northern areas of Pakistan. Thirty bacterial strains were isolated, purified, characterized biochemically and subjected to the metabolic fingerprinting by performing nitrogen fixation, phosphate solubilization, protease, indole acetic acid (IAA) production, antibiotic susceptibility and heavy metal resistance test, lead acetate assay for the H2S production. Strains showing distinct characteristics were further characterized by 16S rDNA sequencing and characterized as Bacillus pumilus (KT273321), Acinetobacter baumanii (KT273323), Acinetobacter junii (KT273324), Pseudomonas aeruginosa (KT273325), Bacillus circulans (KT273326) and Bacillus cereus (KT273327). As most of the strains show positive results for resistance against heavy metals, phosphate solubilization, nitrogen fixation, IAA production, and so these strains might be utilized for the removal of heavy metals from the ecosystem as well as biofertilizer in agriculture lands of northern areas. (author)

Colistin-Resistant Acinetobacter baumannii Clinical Strains with Deficient Biofilm Formation

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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

Outbreak of Acinetobacter baumannii in a neonatal intensive care unit: antimicrobial susceptibility and genotyping analysis.

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Touati, Arabella; Achour, Wafa; Cherif, Ahmed; Hmida, Hayet Ben; Afif, Firas Bou; Jabnoun, Sami; Khrouf, Naima; Hassen, Assia Ben

2009-06-01

We describe an outbreak of nosocomial respiratory infection caused by multi-drug resistant Acinetobacter baumannii in a neonatal intensive care unit (NICU) in Tunis and our investigation to determine the source. Between May 2006 and February 2007, 31 infants hospitalized in the NICU of the Centre of Maternity and Neonatology of La Rabta in Tunis developed A. baumannii pneumonia. A case (infected infant) was defined as any patient hospitalized in the NICU during the outbreak period, with clinical signs of pneumonia and isolation of A. baumannii from tracheal aspirate. Ten rectal swabs and 98 environmental specimens were collected for the epidemiological investigation. Thirty-nine A. baumannii isolates were collected: 31 clinical strains from tracheal aspirates (>10(3) colony-forming units [CFU]/mL), 3 environmental strains from incubators, and 5 from rectal swab. For the genotyping method, we used pulsed-field gel electrophoresis using ApaI restriction endonuclease. Thirty-one neonates developed multiple drug-resistant A. baumannii-associated pneumonia with 10 deaths due to A. baumannii infection, 48.4% had very low birth weight (isolates were resistant to all beta-lactams. Resistance rates to other antibiotics were, respectively, 94.9% for gentamicin, 87.2% for cotrimoxazole, 41% for netilmicin, and 5.1% for tobramycin. All the isolates were susceptible to colistin. Pulsed-field gel electrophoresis analysis of outbreak-isolates indicated the presence of only one clone (A) containing nine subtypes genetically related to the outbreak strain. The clonal diffusion of A. baumannii strains in an NICU was confirmed by molecular method. Control measures were reinforced to contain the outbreak.

Multidrug-resistant Acinetobacter meningitis in neurosurgical patients with intraventricular catheters: assessment of different treatments.

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Rodríguez Guardado, A; Blanco, A; Asensi, V; Pérez, F; Rial, J C; Pintado, V; Bustillo, E; Lantero, M; Tenza, E; Alvarez, M; Maradona, J A; Cartón, J A

2008-04-01

The treatment of multidrug-resistant Acinetobacter baumannii meningitis is a serious therapeutic problem due to the limited penetration of antibiotics into the CSF. We describe the clinical features and the outcome of a group of patients with nosocomial neurosurgical meningitis treated with different therapeutic options. All patients with nosocomial post-surgical meningitis due to A. baumannii diagnosed between 1990 and 2004 were retrospectively reviewed. During the period of study, 51 cases of this nosocomial infection were identified. Twenty-seven patients were treated with intravenous (iv) monotherapy: carbapenems (21 cases), ampicillin/sulbactam (4 cases) and other antibiotics (2 cases). Four patients were treated with iv combination therapy. Nineteen patients were treated with iv and intrathecal regimens: colistin by both routes (8 cases), carbapenems plus iv and intrathecal (4 cases) or only intrathecal (5 cases) aminoglycosides, and others (2 cases). Seventeen patients died due to the infection. One patient died without treatment. The mean (SD) duration of therapy was 17.4 (8.3) days (range 3-44). Although no patients treated with colistin died, we did not observe statistically significant differences in the mortality among the groups with different treatments. Nosocomial Acinetobacter meningitis has a high mortality. Combined therapy with iv and intrathecal colistin is a useful and safe option in the treatment of nosocomial Acinetobacter meningitis.

Isolation of nitrite-degrading strains from Douchi and their application to degrade high nitrite in Jiangshui.

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Guo, Xing; Liu, Bianfang; Gao, Lina; Zhou, Yuan; Shan, Yuanyuan; Lü, Xin

2018-06-01

Excessive nitrite in food is potentially harmful to human health because of its carcinogenic effects caused by nitroso-dervivatives. Douchi, which widely distributed throughout the country, is a traditional solid fermented soybean food with low nitrite content. In this study, bacterias which can degrade nitrite were isolated from Douchi and identified according to 16S rDNA sequence. Acinetobacter guillouiae, Acinetobacter bereziniae, Bacillus subtilis, Bacillus tequilensis, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus aryabhattai and Bacillus methylotrophicus were selected. It was shown that all strains have nitrite degradation capability, in which 99.41 % nitrite can be degraded by Bacillus subtilis NDS1. The enzyme activities of these strains were determined at 24 h and 48 h, which corresponded to their nitrite degradation rates. The strains were firstly tried to inoculate in Jiangshui, which is a kind of traditional fermented vegetable in northwest China and often has high nitrite content. It was found that Bacillus subtilis NDS1, Bacillus tequilensis NDS3, Acinetobacter bereziniae NDS4, Bacillus subtilis NDS6, Bacillus subtilis NDS12 can degrade nitrite in Jiangshui more quickly, among which Acinetobacter bereziniae NDS4 degraded almost all nitrite in 48 h while it took 180 h for control. These results indicated that the selected strains have potential to become nitrite degradition agent in food. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

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

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

2017-02-01

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

A Novel Low-Temperature Alkaline Lipase from Acinetobacter johnsonii LP28 Suitable for Detergent Formulation

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Hai Kuan Wang

2011-01-01

Full Text Available A strain LP28 that produces alkaline and low-temperature lipase was isolated from the soil collected from the Bay of Bohai, PR China and identified as Acinetobacter johnsonii using 16S rDNA sequencing. The lipase was purified to homogeneity by centrifugation, followed by ammonium sulphate precipitation, dialysis, ion exchange chromatography on cellulose DE-52 and gel filtration chromatography on Sephadex G-75. The enzyme was purified about 34-fold with a final yield of 13 % and the relative molecular mass of the enzyme was determined to be 53 kDa by SDS-PAGE. The purified enzyme exhibited maximum activity at 30 °C and pH=9.0, and retained 94.53 % of its maximum activity at 20 °C. The enzyme was stable at 50 °C and retained 80.9 % of its original activity for 30 min. It was also highly stable in a pH range of 8.0–11.0. The enzyme hydrolyzed a wide range of oils and showed a high level of lipase activity in hydrolyzing tributyrin. The enzyme activity was promoted in the presence of Na+, Ca2+, K+, Mg2+ and sodium citrate. Ba2+, Mn2+, Cr3+ and Co2+ did not affect the enzyme activity, whereas the presence of Al3+, Cu2+, Fe2+, Fe3+, Zn2+ and EDTA reduced the enzyme activity. Regarding the stability of detergent process, the enzyme was highly stable in the presence of various oxidizing agents, some commercial detergents and alkaline protease, and its activity was also promoted by most of the surfactants, viz. Tween 20, Tween 80, sodium cholate, sodium taurocholate and saponin. For these characteristics, the lipase from Acinetobacter johnsonii LP28 showed good potential as an additive in laundry detergent formulation.

PER-1 production in a urinary isolate of Providencia rettgeri.

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Bahar, G; Eraç, B; Mert, A; Gülay, Z

2004-08-01

A Providencia rettgeri strain resistant to extended-spectrum cephalosporins and intermediate to aztreonam was isolated from the urine of a patient hospitalized in the urology clinic of SSK Educational Hospital in Ankara. Clavulanic acid restored the activity of extended-spectrum cephalosporins, suggesting that the strain was harboring an extended-spectrum beta-lactamase. Since the PER-1 enzyme is widespread in Turkey, and had been already detected in a related species such as Proteus mirabilis, the Providencia strain was suspected of harboring a PER-1 enzyme, which was indeed detected by PCR. This is the first description in a P. rettgeri isolate of a PER-1 enzyme which is widespread among Acinetobacter baumanni and Pseudomonas aeruginosa strains in Turkey.

Identification of New Delhi metallo-β-lactamase 1 in Acinetobacter lwoffii of food animal origin.

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Yang Wang

Full Text Available BACKGROUND: To investigate the presence of metallo-β-lactamase (MBL genes and the genetic environment of the New Delhi metallo-β-lactamase gene bla(NDM-1 in bacteria of food animal origin. METHODOLOGY/PRINCIPAL FINDINGS: Gram-negative bacteria with low susceptibility to imipenem (MIC>8 µg/mL were isolated from swab samples collected from 15 animal farms and one slaughterhouse in eastern China. These bacteria were selected for phenotypic and molecular detection of known MBL genes and antimicrobial susceptibility testing. For the bla(NDM-1 positive isolate, conjugation and transformation experiments were carried out to assess plasmid transfer. Southern blotting was conducted to localize the bla(NDM-1 genes, and DNA sequencing was performed to determine the sequences of bla(NDM-1 and the flanking genes. In total, nine gram-negative bacteria of four different species presented a MBL phenotype. bla(NDM-1 was identified on a mobile plasmid named pAL-01 in an Acinetobacter lwoffii isolate of chicken origin. Transfer of pAL-01 from this isolate to E. coli J53 and JM109 resulted in resistance to multiple β-lactams. Sequence analysis revealed that the bla(NDM-1 gene is attached to an intact insertion element ISAba125, whose right inverted repeat (IR-R overlaps with the promoter sequence of bla(NDM-1. Thus, insertion of ISAba125 likely enhances the expression of bla(NDM-1. CONCLUSION: The identification of a bla(NDM-1- carrying strain of A. lwoffii in chickens suggests the potential for zoonotic transmission of bla(NDM-1 and has important implications for food safety.

Analysis of Acinetobacter baumannii resistance patterns in patients with chronic obstructive pulmonary disease (COPD) in terms of choice of effective empiric antibiotic therapy.

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Grochowalska, Aneta; Kozioł-Montewka, Maria; Sobieszczańska, Anna

2017-06-12

Introduction. Multi-resistant Acinetobacter baumannii isolated from patients has become one of the most hazardous pathogens in health care settings. The aim of the study was to analyze pneumonia caused by Acinetobacter baumannii in patients hospitalized because of exacerbation of chronic obstructive pulmonary diseases (COPD), who were admitted to the Pulmonology Ward of the Masovian Specialistic Hospital in Radom (MSS). The incidence and drug sensitivity of these non-fermenting rods were evaluated, and compliance with antimicrobial procedure with the algorithm of the guidelines in applicable recommendations, was estimated. This should result in determining the local patterns of resistance and verifying therapeutic procedures in accordance with the assumptions of hospital antibiotic policy. In addition, the study examined the effectiveness of empiric and targeted therapy according to the clinical condition of the patient, and the eradication of A. baumannii, in comparison with the aggravating factors of the patient. Materials and Method. The retrospective study included 90 patients with exacerbation of COPD whose etiological factor of infection was A. baumannii, hospitalized in the Department of Pulmonology (MSS) in 2012-2016. Results. Studies were conducted on 90 patients with COPD exacerbation from which A. baumannii was isolated. Co-infections with other bacterial species among 41 patients were additionally noted. The majority of A. baumannii strains showed a high resistance (90%) to fluoroquinolones, ceftazidime, piperacillin/tazobactam. For strains causing a co-infection, drug resistance was successively 44-56%, 44%, 44%. All of patients received empirical therapy. The most commonly used drug was amoxicillin with a clavulanic acid, often combined with fluoroquinolone. This type of therapy was effective among 10% of patients. The mortality in this group was determined at 29%. Among 79% of patients with COPD, a targeted therapy was performed which proved to be

Molecular identification of tigecycline- and colistin-resistant carbapenemase-producing Acinetobacter baumannii from a Greek hospital from 2011 to 2013.

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Mavroidi, Angeliki; Likousi, Sofia; Palla, Eleftheria; Katsiari, Maria; Roussou, Zoi; Maguina, Asimina; Platsouka, Evangelia D

2015-09-01

An alarming increase in the resistance rates of tigecycline and colistin among carbapenemase-producing Acinetobacter baumannii recovered from a Greek hospital over a 3-year period (2011-2013) was investigated. The antimicrobial resistance profiles and carbapenemase gene content were determined for a collection of colistin- and/or tigecycline-resistant carbapenemase-producing A. baumannii isolates (n = 42), which were recovered consecutively during the study period. A gradual increase in the incidence of blaOXA-23 producers was observed from 2011 to 2013. A cluster of 21 isolates comprised tigecycline-resistant blaOXA-23 producers displayed a single antimicrobial resistance pattern. The emergence of two blaOXA-23 producers resistant to both tigecycline and colistin was documented. Furthermore, determination of the mechanisms of colistin and tigecycline resistance and molecular typing by the tri-locus sequence typing (3LST) scheme for nine isolates recovered from bloodstream infections were performed. Out of nine isolates, five tigecycline- and two colistin-resistant isolates were blaOXA-23 producers of 3LST ST101 corresponding to the international clone II recovered during 2012-2013. All nine isolates were positive for the presence of the adeB gene of the AdeABC efflux pump. Three colistin-resistant isolates possessed novel substitutions in PmrB, which may be implicated in colistin resistance. To the best of our knowledge, this is the first report of the acquisition of tigecycline and colistin resistance among blaOXA-23-producing A. baumannii of 3LST ST101 in Greece; thus, continuous surveillance and molecular characterization, prudent use of antibiotics and implementation of infection control measures for A. baumannii are urgent.

A 4-year surveillance of antimicrobial resistance patterns of Acinetobacter baumanni in a university-affiliated hospital in China.