Acinetobacter Baumannii In Hospital Research Articles

Isolation and Characterization of Novel Bacteriophages to Target Carbapenem-Resistant Acinetobacter baumannii.

The spread of multidrug-resistant Acinetobacter baumannii in hospitals and nursing homes poses serious healthcare challenges. Therefore, we aimed to isolate and characterize lytic bacteriophages targeting carbapenem-resistant Acinetobacter baumannii (CRAB). Of the 21 isolated A. baumannii phages, 11 exhibited potent lytic activities against clinical isolates of CRAB. Based on host spectrum and RAPD-PCR results, 11 phages were categorized into four groups. Three phages (vB_AbaP_W8, vB_AbaSi_W9, and vB_AbaSt_W16) were further characterized owing to their antibacterial efficacy, morphology, and whole-genome sequence and were found to lyse 37.93%, 89.66%, and 37.93%, respectively, of the 29 tested CRAB isolates. The lytic spectrum of phages varied depending on the multilocus sequence type (MLST) of the CRAB isolates. The three phages contained linear double-stranded DNA genomes, with sizes of 41,326-166,741 bp and GC contents of 34.4-35.6%. Genome-wide phylogenetic analysis and single gene-based tree construction revealed no correlation among the three phages. Moreover, no genes were associated with lysogeny, antibiotic resistance, or bacterial toxins. Therefore, the three novel phages represent potential candidates for phage therapy against CRAB infections.

Contribution of different mechanisms to aminoglycoside resistance in clinical isolates of Acinetobacter baumannii

The antibiotics overuse for infection treatment was the sparkle in the spreading of multi-drug resistance Acinetobacter baumannii in hospitals. In our study, we evaluated the contribution of the aminoglycoside resistance mechanisms of A. baumannii to the resistance surge in some selected Egyptian hospitals with a checkerboard assay application to retrieve the aminoglycoside activity. The resistance profile analysis of collected 200 A. baumannii isolates revealed a multidrug-resistant pattern with limited susceptibilities to aminoglycosides. Analysis of the prevalence of aminoglycoside-modifying enzyme (AMEs) genes revealed the presence of the six AMEs genes either singly or in combination in selected isolates and aph (3)-VIa gene was the predominant one. At the same time, four efflux pump genes of AdeABC and AdeKJL family showed significant (P < 0.001) up-regulation levels. Moreover, the implementation of combination strategy showed fourteen synergistic activities against two high-level aminoglycoside-resistance (HLAR) A. baumannii isolates. The findings highlighted the alarming levels of aminoglycoside resistance in A. baumannii isolates, which proved that a common enzymatic modification mechanism acts synergistically with decreased antibiotic accumulation in acquiring aminoglycoside resistance. Additionally, the study provides useful information for the promising synergistic combination therapy that reduces the therapeutic dose of aminoglycosides used and subsequently increases their clinical application.

Molecular analysis of the prevalence of Acinetobacter baumannii in hospitals and the surrounding environments: a cross-sectional study

Acinetobacter baumannii is widely recognized in clinical environments due to its infectious capacity, antimicrobial adaptability, and lethality. Analyzing the prevalence of this agent in intra- and extra-hospital environments may reveal target indicators for appropriate management interventions. In this observational cross-sectional study, we evaluated the prevalence of A. baumannii within hospitals with intensive care units and in their external surroundings in a macro-health region of Brazil. Samples of Columba livia (pigeon) droppings from the external environment of four hospitals (n = 40), from floor surfaces (n = 20), and door handles (n = 20) of different hospital wards were collected based on random sampling, all of which were evaluated for the presence of A. baumannii using polymerase chain reactions (PCR). The sensitivity and specificity of the technique was verified after the collected samples were contaminated with clinical samples positive for A. baumannii. We detected a significantly higher A. baumannii prevalence (87.50%, CI = 71.29–100.00) in samples collected within the hospital environment compared with those obtained from the external environment (12.50%, CI = 0.00–28. 71) (p = 0.003). In addition, samples collected from floor surfaces contained bacterial densities (181.3 ± 11.58) that exceeded those in environmental (93.32 ± 1.56) and door handle (142.70 ± 17.14) samples by 94% and 78.71%, respectively. The findings of this study will enhance our understanding of the spatial distribution of A. baumannii and additionally, validate the efficiency of PCR for diagnosis of this infectious agent.

Evaluation of genetic diversity of colistin-resistant Acinetobacter baumannii by BOX-PCR and ERIC-PCR: the first report.

Aim: To control the spread of Acinetobacter baumannii in hospitals, it is necessary to identify the reservoir of organisms and the way they are transmitted. This study analyzed samples by BOX-PCR and enterobacterial repetitive intergenic consensus PCR techniques. Methods: Isolated strains were identified using the Microgen kit and blaOXA-51 gene. The genetic diversity of strains that weresensitive or resistant to colistin was evaluated by BOX-PCR and enterobacterial repetitive intergenic consensus PCR methods. Results: A total of 13% of the isolates were resistant to colistin, whereas 87% of the strains were sensitive to this medication. A. baumannii strains that wereresistant or sensitive to colistin were divided into five groups using the BOX-PCR method and six groups using the enterobacterial repetitive intergenic consensus PCR method. Conclusion: Rapid identification and the use of appropriate tools to control colistin-resistant clones are essential to prevent the further spread of A. baumannii.

Evaluating the Effectiveness of Hospital Antiseptics on Multidrug-Resistant Acinetobacter baumannii: Understanding the Relationship between Microbicide and Antibiotic Resistance.

Acinetobacter baumannii hospital infections are difficult to treat due to the rapid emergence of multidrug-resistant (MDR) strains. In addition, A. baumannii can survive in numerous adverse environments, including in the presence of common hospital antiseptics. We hypothesized that in addition to accumulating drug resistance determinants, MDR A. baumannii strains also accumulate mutations that allow for greater microbicide tolerance when compared to pan-susceptible (PS) strains. To test this hypothesis, we compared the survival of five MDR and five PS patient isolates when exposed to bleach, ethanol, quaternary ammonium compounds, chlorhexidine gluconate, and povidone. We evaluated bacteria in a free-living planktonic state and under biofilm conditions. Each disinfectant eliminated 99.9% of planktonic bacteria, but this was not the case for bacterial biofilms. Next, we characterized strains for the presence of the known microbicide-resistance genes cepA, qacEΔ1, qacE, and qacA. MDR strains did not survive more than PS strains in the presence of microbicides, but microbicide-resistant strains had higher survival rates under some conditions. Interestingly, the PS strains were more likely to possess microbicide-resistance genes. Microbicide resistance remains an important topic in healthcare and may be independent of antimicrobial resistance. Hospitals should consider stricter isolation precautions that take pan-susceptible strains into account.

Acinetobacter baumannii – a problematic microorganism with increasing antibiotic resistance

Introduction In the last years, the growing antibiotic resistance of Acinetobacter baumannii isolates has been registered all over the world, incl. in our country. This increases the cost of treatment, burdens health care facilities and staff, and - on an individual level - worsens the quality of life of patients, especially the risk of death. The aim of this study is to discuss up-to-date data on the problematic and increasing antibiotic resistance of Acinetobacter baumannii and their containment. Materials and Methods Information from the last five years is selected from scientific databases: CDC, ECDC, Elsevier, PubMed, Sciencedirect, BulSTAR, Medical Institute of Ministry of Internal Affairs. Results and Discussion According to experts, emergence of carbapenem-resistant A. baumannii should be contained using complex measures: screening of risky patients, increased measures in infection control and antimicrobial stewardship. The COVID-19 pandemic over the past year has contributed to increase in resistance due to the heightened and in many cases irrational use of often broad-spectrum antibiotics. The need for laboratory testing of susceptibility/ resistance of carbapenem-resistant Acinetobacter baumannii hospital isolates to antimicrobials is frequently overlooked. Conclusions Strict control of infections is needed to limit the increasing resistance of Acinetobacter baumannii, including through monitoring, and an early and accurate laboratory diagnosis. It is necessary to raise the level of awareness regarding antibiotic policy, both among medical professionals and among people in society as a whole, through information events and materials.

Risk factors for nosocomial rectal colonization with carbapenem-resistant Acinetobacter baumannii in hospital: a matched case\u2013control study

BackgroundDuring the last decade carbapenem-resistant Acinetobacter baumannii (CRAB) became hyper-endemic in hospitals due to difficult to control spreading. Our aim is to identify risk factors for nosocomial rectal CRAB colonization in an endemic hospital.MethodsA retrospective matched case–control study (ratio 1:2) with a prospective inclusion of cases and concurrent selection of controls was conducted from January 2017 to December 2018 in a tertiary-care hospital. Universal active surveillance for CRAB was implemented. Univariate and multivariate logistic regression was carried out using a stepwise selection method to compare prognostic factors between cases and controls. A sub-analysis was carried out according to the type of department.ResultsForty-five cases with nosocomial rectal CRAB colonization and 90 controls were included. One hundred and two (75%) patients were hospitalized in medical departments. At multivariable analysis significant risk factors associated with CRAB colonization were: use of permanent devices (OR 10.15, 95% CI 2.27–45.39; P = 0.002), mechanical ventilation (OR 40.01, 95% CI 4.05–395.1; P = 0.002), urinary catheters (OR 4.9, 95% CI 1.52–16.19; P = 0.008), McCabe score (OR 5.45, 95% CI 1.87–15.89; P = 0.002), length of stay (OR 1.03, 95% CI 1.01–1.05; P = 0.002), carbapenem use (OR 5.39, 95% CI 1.14–25.44; P = 0.033). The sub-analysis showed that patients admitted to different departments had different risk factors. In geriatric department a fatal disease and a longer hospital stay represented significant risk factors both in univariate and multivariate analysis, while in internal medicine department the use of permanent devices, current antibiotic therapy and antibiotic polytherapy represented significant risk factors for CRAB at the univariate analysis, also confirmed in multivariate analysis.ConclusionsOur data suggest that active surveillance for rectal CRAB colonization should be addressed to patients with an unfavourable prognosis, longer hospitalizations and carriers of multiple devices. To counter CRAB spreading in endemic settings, clinicians must limit the use of carbapenems, and reinforce interventions aimed at proper use of devices.

Mycobacterium Tuberculosis, Culturing and PCR Optimization

The genus Acinetobacter baumannii has undergone substantial taxonomic modifications over the last 30 years. Acinetobacter baumannii is one of the most important representatives of the genus and pathogen for healthcare facilities globally. Over the last 15 years, its clinical significance shows that it has the ability to acquire resistance against antibiotics in this threatening antibiotic era. Naturally A.baumannii can easily be isolated from different sources throughout whole world, found mostly in water, soil, sputum and many healthcare environments, is a non-fermenting, non-spore forming and gram negative coccobacilli. Pneumonia caused by MDR strains of Acinetobacter baumannii creating serious issues for Physicians to treat it properly. Risk factor for two types of patients recognized to pneumonia infection Acinetobacter baumannii hospital associated pneumonia (AHAP) and Acinetobacter baumannii ventilator associated pneumonia (AVAP), by univariate analysis prior to ceftazidime treatment. It is to be reported that potential risk factors for AVAP includes, imipenem resistance, long duration of hospital stay and fluoroquinolones exposure.

Whole genome sequencing of Acinetobacter baumannii hospital isolates from Terengganu, Malaysia: Prevalence of the GC2 ST195 clone in 2011–2012

Whole genome sequencing of Acinetobacter baumannii hospital isolates from Terengganu, Malaysia: Prevalence of the GC2 ST195 clone in 2011–2012

Multidrug resistant and extensively drug resistant Acinetobacter baumannii hospital infection associated with high mortality: a retrospective study in the pediatric intensive care unit

BackgroundMultidrug resistant (MDR) and extensively drug resistant (XDR) Acinetobacter baumannii presents challenges for clinical treatment and causes high mortality in children. We aimed to assess the risk factors and overall mortality for MDR/XDR Acinetobacter baumannii infected pediatric patients.MethodsThis retrospective study included 102 pediatric patients who developed MDR/XDR Acinetobacter baumannii infection in the pediatric intensive care unit (PICU) of Shanghai Children’s Hospital in China from December 2014 to May 2018.Acinetobacter baumannii clinical isolates were recovered from different specimens including blood, sputum, bronchoalveolar lavage fluid, cerebrospinal fluid, ascites, hydrothorax, and urine. Antibiotic susceptibility test was determined according to the Clinical and Laboratory Standards Institute interpretive criteria. Clinical and biological data were obtained from the patients’ medical records.Results102 patients with Acinetobacter baumannii infection were enrolled. The median age was 36 (9.6, 98.8) months, and there were 63 male in the case group. The overall mortality rate was 29.4%, while the Acinetobacter baumannii-associated mortality rate was 16.7% (17/102, 12 bloodstream infections, 4 meningitis and 1 intra-abdominal infection). Bloodstream infections occurred in 28 patients (27.5%), and 10 patients (9.8%) among them had central line-associated bloodstream infections (6 central venous catheters, 2 PICCs, 1 venous infusion port and 1 arterial catheter). Cerebrospinal fluid (CSF) cultures were positive in 4(3.9%) patients. 14(13.7%) patients got positive cultures in ascites and hydrothorax. Lower respiratory isolates (56/102) accounted for 54.9% of all patients. Non-survival patients appeared to have a lower NK cell activity (6.2% ± 3.61% vs. 9.15% ± 6.21%, P = 0.029), higher CD4+ T cell ratio (39.67% ± 12.18% vs. 32.66% ± 11.44%, P = 0.039),and a higher serum level of interlukin-8 (IL-8, 15.25 (1.62, 47.22)pg/mL vs. 0.1 (0.1, 22.99)pg/mL, P = 0.01) when Acinetobacter baumannii infection developed. Multivariate logistic analysis indicated that high serum level of Cr (RR, 0.934, 95%CI, 0.890–0.981; P = 0.007) and high BUN/ALB level (RR, 107.893, 95%CI, 1.425–870.574; p = 0.005) were associated with high risk of mortality in MDR/XDR Acinetobacter baumannii infected patients.ConclusionMDR/XDR Acinetobacter baumannii infection is a serious concern in pediatric patients with high mortality. Bloodstream and central nervous system infection accounted for high risk of death. Acute kidney injury is associated with high risk of mortality.

Whole-Genome-Sequence-Based Characterization of Extensively Drug-Resistant Acinetobacter baumannii Hospital Outbreak.

Carbapenem-resistant Acinetobacter baumannii (CRAB) is an important opportunistic pathogen linked to a variety of nosocomial infections and hospital outbreaks worldwide. This study aimed at investigating and characterizing a CRAB outbreak at a large tertiary hospital in Lebanon. A total of 41 isolates were collected and analyzed using pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing (WGS) was performed on all the isolates, and long-read PacBio sequencing was used to generate reference genomes. The multilocus sequence types (MLST), repertoire of resistance genes, and virulence factors were determined from the sequencing data. The plasmid content was analyzed both in silico and using the A. baumannii PCR-based replicon typing (AB-PBRT) method. Genome analysis initially revealed two clones, one carrying blaOXA-23 on Tn2006 (ST-1305, ST-195, and ST-218) and another carrying blaOXA-72 on pMAL-1 (ST-502 and ST-2059, a new ST), with the latter having two subclones, as revealed using the Bayesian transmission network. All isolates were extensively drug resistant (XDR). WGS analysis revealed the transmission pathways and demonstrated the diversity of CRAB isolates and mobile genetic elements in this health care setting. Outbreak detection using WGS and immediate implementation of infection control measures contribute to restraining the spread and decreasing mortality.IMPORTANCE Carbapenem-resistant Acinetobacter baumannii (CRAB) has been implicated in hospital outbreaks worldwide. Here, we present a whole-genome-based investigation of an extensively drug-resistant CRAB outbreak rapidly spreading and causing high incidences of mortality at numerous wards of a large tertiary hospital in Lebanon. This is the first study of its kind in the region. Two circulating clones were identified using a combination of molecular typing approaches, short- and long-read sequencing and Bayesian transmission network analysis. One clone carried blaOXA-23 on Tn2006 (ST-1305, ST-195, and ST-218), and another carried blaOXA-72 on a pMAL-1 plasmid (ST-502 and ST-2059, a new ST). A pMAL-2 plasmid was circulating between the two clones. The approaches implemented in this study and the obtained findings facilitate the tracking of outbreak scenarios in Lebanon and the region at large.

Virulence characteristics of multidrug resistant biofilm forming Acinetobacter baumannii isolated from intensive care unit patients

BackgroundNosocomial infections and persistence of multidrug resistant biofilm forming Acinetobacter baumannii in hospitals has made it as a serious problem in healthcare settings worldwide.MethodsA total of 100 A. baumannii clinical isolates from immunocompromised patients hospitalized in ICU were investigated for biofilm formation, the presence of biofilm related genes (bap, ompA, csuE, fimH, epsA, blaPER-1, bfmS, ptk, pgaB, csgA, kpsMII), integron characterization and molecular typing based on REP-PCR.ResultsAll isolates were resistant to three or more categories of antibiotics and considered as multidrug resistant (MDR). A total of 32 isolates were resistant to all tested antibiotics and 91% were extensively drug-resistance (XDR). All isolates were able to produce biofilm and 58% of isolates showed strong ability to biofilm formation. All strong biofilm forming A. baumannii isolates were XDR. All A. baumannii isolates carried at least one biofilm related gene. The most prevalent gene was csuE (100%), followed by pgaB (98%), epsA and ptk (95%), bfmS (92%) and ompA (81%). 98% of isolates carried more than 4 biofilm related genes, simultaneously. Class I integron (67%) was more frequent in comparison with class II (10%) (P < 0.05). The REP-PCR patterns were classified as 8 types (A-H) and 21 subtypes. The A1 (23%) and C1 (15%) clusters were the most prevalent among A. baumannii isolates (P < 0.05). According to the REP-PCR patterns, 23% of all isolates had a clonal relatedness.ConclusionOur study revealed the high frequency of biofilm forming XDR A. baumannii in ICU patients, with a high prevalence of biofilm related genes of csuE and pgaB. It seems that the appropriate surveillance and control measures are essential to prevent the emergence and transmission of XDR A. baumannii in our country.

Acinetobacter baumannii Hospital Acquired Infections.

Abstract not available&#x0D; Bangladesh J Med Microbiol 2019; 13 (1): 1-3

Transition of blaOXA-58-like to blaOXA-23-like in Acinetobacter baumannii Clinical Isolates in Southern China: An 8-Year Study.

BackgroundThe prevalence of carbapenem-resistant Acinetobacter baumannii in hospitals has been increasing worldwide. This study aims to investigate the carbapenemase genes and the clonal relatedness among A. baumannii clinical isolates in a Chinese hospital.MethodsCarbapenemase genes and the upstream locations of insertion sequences were detected by polymerase chain reaction (PCR), and the clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing.ResultsA total of 231 nonduplicate carbapenemase gene-harboring A. baumannii clinical isolates recovered from Shenzhen People’s Hospital, were investigated between 2002 and 2009. bla OXA-23-like, bla OXA-58-like, bla OXA-40-like, and ISAba1-bla OXA-51-like were identified in 119, 107, 1, and 4 isolates, respectively. IS1008-ΔISAba3, ISAba3, and ISAba1 were detected upstream of the bla OXA-58-like gene in 69, 35, and 3 isolates, respectively. All bla OXA-23-like genes but one had an upstream insertion of ISAba1. bla OXA-58-like was the most common carbapenemase gene in A.baumannii before 2008, thereafter bla OXA-23-like became rapidly prevalent and replaced bla OXA-58-like in 2009. The majority of bla OXA-58-like-carrying isolates showed lower level of resistance to imipenem and meropenem (minimum inhibitory concentrations (MICs), 1 μg/ml to 16 μg/ml), compared with the majority of bla OXA-23-like-carrying isolates (MICs, 16 μg/ml to 64 μg/ml for both imipenem and meropenem). All 231 bla OXA carbapenemase gene-harboring isolates belonged to 14 PFGE types (A–N), and three dominant clones A, J, and H accounted for 43.3%, 42.0%, and 8.2% of the tested isolates, respectively. Clone A (sequence type ST92/ST208) with bla OXA-58-like was the most prevalent before 2008. Clone H (ST229) with bla OXA-23-like became striking between 2007 and 2008. Clone J (ST381) with bla OXA-23-like rapidly spread and replaced clones A and H in 2009.ConclusionThis study is the first to reveal that the distinct bla OXA-23-like-carrying A. baumannii ST381 displaced the previously prevalent bla OXA-58-like-carrying A. baumannii ST92/ST208, resulting in the rapidly increasing resistance to carbapenems in A. baumannii in Shenzhen People’s Hospital in 2009.

Prevalence of digestive tract colonization of carbapenem-resistant Acinetobacter baumannii in hospitals in Saudi Arabia.

Carbapenem-resistant Acinetobacter baumannii is a major health problem worldwide, especially in intensive care units (ICUs). This study aimed to detect the prevalence of A. baumannii colonization of the gastrointestinal tract of patients admitted to the ICU in two hospitals in Saudi Arabia. In addition, it aimed to characterize the molecular mechanisms of carbapenem resistance in these isolates. From January to June 2014, 565 rectal swab specimens were screened for Acinetobacer strains and carbapenem resistance using CHROMagar Acinetobacter and CHROMagar KPC agar plates, respectively. Organism identification and susceptibility were detected using the Vitek 2 system. A total of 47 Acinetobacter spp. were detected, and 35 were resistant to carbapenem, making the prevalence of Acinetobacter spp. 8.3% (47/565) and carbapenem resistance (6.2%, 35/565). The 47 strains showed remarkable clonal diversity as revealed by PFGE. Using PCR, OXA-51, a chromosomal marker for A. baumannii, was detected in 46 strains. OXA-23 β-lactamase was detected in all 35 carbapenem-resistant A. baumannii. No IMP, VIM, SPM, SIM, GIM, KPC or NDM β-lactamases were detected in these isolates. Thus, OXA-23 was the main mechanism of carbapenem resistance in these isolates. To the best of our knowledge, this is the first study to detect the prevalence of Acinetobacter colonization in the digestive tract of ICU patients in Saudi Arabia. This study revealed the importance of having well-established protocols for early identification of these multidrug-resistant organisms, optimizing infection-control strategies and having active surveillance studies to reduce morbidity, mortality and cost.

Analysis of drug-resistant gene detection of blaOXA-like genes from Acinetobacter baumannii

Our study determines the resistance gene profile of a set of Acinetobacter baumannii hospital isolates. A. baumannii is responsible for nosocomial outbreaks and sporadic infections. We extracted and PCR amplified bacterial DNA isolated from patients with ages below 60 years (23.36%) and above 60 years (76.64%). Most of the patients were admitted in the ICU (36.13%) and pneumology departments (28.47%). Of 164 isolated strains, 16 (9.75%) contained OXA-51, 8 (4.88%) contained OXA-58, and 140 (85.37%) contained both OXA-51 and OXA-23. Additionally, 8 (7.41%) strains containing OXA-58 and 100 (92.59%) strains containing both OXA-51 and OXA-23 showed multidrug-resistance. Drug resistance rates of A. baumannii to amikacin, tobramycin-levofloxacin, and cotrimoxazole were above 90%, while drug resistance rates to ampicillin, cefotetan, cefazolin, cefoperazone, and nitrofurantoin were 100%. In conclusion, we found that isolated strains containing OXA-51 and OXA-23 were more likely to be resistant or have decreased sensitivity to carbapenems.

In Vitro Activity of Tigecycline and Colistin against clinical isolates of Acinetobacter baumannii in Hospitals in Tehran and Bandar-Abbas, Iran.

Background:The Acinetobacter species, particularly A. baumannii, has emerged as one of the main causes of nosocomial infections in recent years. The high prevalence of drug resistance in A. baumannii limits the therapeutic options for treating infections caused by these bacteria. The objective of this study was to determine the in vitro activity of Tigecycline and Colistin against clinical isolates of A. baumannii in Tehran and Bandar Abbas, Iran.Methods:This study was conducted from March 2009 to November 2010 at three hospitals in Tehran and Bandar Abbas, Iran, using 165 Acinetobacter species isolated from clinical specimens. All isolates were subjected to PCR to detect blaOXA-51-like genes that are unique to Acinetobacter baumannii. Isolates that gave a band for the blaOXA-51-like genes were identified as A. baumannii. Anti-microbial susceptibility tests were performed for Tigecycline, Colistin, and other antibiotics.Results:Sensitivity rates to Colistin and Polymyxin-B were 100%. Resistance rates for Tigecycline were 4.2% in Tehran and 8.8% in Bandar-Abbas according to Jones criteria, whereas, according to U.S. FDA criteria, the resistance rates were 20.8% and 17.6%, respectively.Conclusions:New alternative drugs are needed for the treatment of drug resistant A. baumannii. Although Colistin appears to be a good choice, adverse reactions have limited its usage. Tigecycline is effective against A. baumannii isolates, and it shows promise for solving the problem.

334Emergence of OXA-23-possessing Acinetobacter baumannii in Hospitals in New York City

334Emergence of OXA-23-possessing Acinetobacter baumannii in Hospitals in New York City

Drug resistance analysis of pan-drug-resistant Acinetobacter baumannii in hospital

To investigate current situation of pan-drug-resistant Acinetobacter baumannii in hospital and its drug-resistance , then provide reference for rational use of antibiotics in clinic. All kinds of microbial test specimens from January 2009 to December 2012 of hospitalized patients were cultured and separated. VITEK 2-Compact fully automatic microorganism analyzer was used to identify and analyze drug sensitivity. Three hundred and seven strains pan-drug-resistant Acinetobacter baumannii were isolated in 4 years, the primarily source were sputum, accounted for 69.4%, followed by the wound secretion 14.7%. The highest three places of samples separation of extensive drug-resistant Acinetobacter baumannii positive was intensive care unit (ICU, accounted for 26.4%), department of respiratory medicine (accounted for 26.1%) and department of geriatrics (accounted for 23.1%). Extensive drug-resistant Acinetobacter baumannii almost completely resisted to clinical commonly used antimicrobial agents, drug resistant rate could be as high as 100% such as cefotaxime, meropenem, piperacillin, imipenem, ciprofloxacin, and tetracycline except for cefoperazone-sulbactam and polymyxin, and the rate of other drugs were all above 90%. Drug-resistant of cefoperazone-sulbactam was nearly 30% in our hospital, and sensitive rate was 100% to polymyxin. Pan-drug-resistant Acinetobacter baumannii is resistant for most clinical commonly used antimicrobial drug, antimicrobial agents were chosen according to drug susceptibility testing. Antibacterial drugs such as polymyxin and cefoperazone-sulbactam or sulbactam contained drugs can be selected for pan-drug-resistant.

Quantitative Profiling and Identification of Outer Membrane Proteins of β-Lactam Resistant Strain of Acinetobacter baumannii

In the recent past, Acinetobacter baumannii in hospitals has become increasingly resistant to a number of antibiotics including the latest carbapenems and this is of great concern. Here, for the first time, we report 2D-Differential In-Gel Electrophoresis (DIGE) analysis of outer membrane proteome of ATCC 19606 and carbapenem-resistant strain of A. baumannii. Using biological variance analysis (BVA), we identified 25 differentially expressed proteins with a fold difference >or=2; confidence >90% and statistical significance p <or= 0.05. By applying MALDI TOF/TOF and ESI MS/MS proteomic approach to carbapenem-resistant A. baumannii, we identified four porins whose expression was significantly downregulated and a large number of upregulated proteins with specific transport and enzymatic properties. All the following synergistically give advantage to the resistant A. baumannii for survival: (i) high expression of altered CarO isoforms with possible low influx efficiency, (ii) elevated levels of CsuA/B with high adhesive properties, (iii) overexpression of pivotal nutrient transporters, (iv) continued expression of the major OmpAb, and (v) induced production of proteins of hypothetical origin. This proteomic study provides a platform to understand the complex nature of beta-lactam resistance in A. baumannii.