Study of the carbapenem resistance mechanisms in clinical isolates of Acinetobacter baumannii: Comparison of burn and non-burn strains

Burns ◽  
2013 ◽  
Vol 39 (7) ◽  
pp. 1414-1419 ◽  
Author(s):  
Omid Pajand ◽  
Mohammad Ahangarzadeh Rezaee ◽  
Mohammad Reza Nahaei ◽  
Reza Mahdian ◽  
Mohammad Aghazadeh ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates

scholarly journals Prevalence of OXA-Type β-Lactamase Genes among Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates in Thailand

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 864
Author(s):  
Krit Thirapanmethee ◽  
Thayapa Srisiri-a-nun ◽  
Jantana Houngsaitong ◽  
Preecha Montakantikul ◽  
Piyatip Khuntayaporn ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Tertiary Care ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Health Concern ◽  
Drug Of Choice ◽  
Carbapenem Resistant ◽  
Resistance Rates ◽  
Tertiary Care Hospitals

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a critical health concern for the treatment of infectious diseases. The aim of this study was to investigate the molecular epidemiology of CRAB emphasizing the presence of oxacillinase (OXA)-type β-lactamase-encoding genes, one of the most important carbapenem resistance mechanisms. In this study, a total of 183 non-repetitive CRAB isolates collected from 11 tertiary care hospitals across Thailand were investigated. As a result, the blaoxa-51-like gene, an intrinsic enzyme marker, was detected in all clinical isolates. The blaoxa-23-like gene was presented in the majority of isolates (68.31%). In contrast, the prevalence rates of blaoxa-40/24-like and blaoxa-58-like gene occurrences in CRAB isolates were only 4.92% and 1.09%, respectively. All isolates were resistant to carbapenems, with 100% resistance to imipenem, followed by meropenem (98.91%) and doripenem (94.54%). Most isolates showed high resistance rates to ciprofloxacin (97.81%), ceftazidime (96.72%), gentamicin (91.26%), and amikacin (80.87%). Interestingly, colistin was found to be a potential drug of choice due to the high susceptibility of the tested isolates to this antimicrobial (87.98%). Most CRAB isolates in Thailand were of ST2 lineage, but some belonged to ST25, ST98, ST129, ST164, ST215, ST338, and ST745. Further studies to monitor the spread of carbapenem-resistant OXA-type β-lactamase genes from A. baumannii in hospital settings are warranted.

Diversity of polymyxin resistance mechanisms among Acinetobacter baumannii clinical isolates

2017 ◽  
Vol 87 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Raquel Girardello ◽  
Marina Visconde ◽  
Rodrigo Cayô ◽  
Regina Célia Bressan Queiroz de Figueiredo ◽  
Marcelo Alves da Silva Mori ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Resistance Mechanisms ◽  
Clinical Isolates

scholarly journals Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates from Egyptian Patients

2020 ◽  
Author(s):  
Reem M Hassan ◽  
Sherifa T Salem ◽  
Saly Ismail Mostafa Hassan ◽  
Asmaa Sayed Hegab ◽  
Yasmine S Elkholy
Keyword(s):  
Acinetobacter Baumannii ◽  
Molecular Characterization ◽  
Antimicrobial Agents ◽  
Treatment Options ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Common Mechanism ◽  
Carbapenem Resistant ◽  
Egyptian Patients ◽  
Global Threat

AbstractAcinetobacter baumannii (A. baumannii) represents a global threat owing to its ability to resist most of the currently available antimicrobial agents. Moreover, emergence of carbapenem resistant A. baumannii (CR-AB) isolates limits the available treatment options. Enzymatic degradation by variety of ß-lactamases, have been identified as the most common mechanism of carbapenem resistance in A. baumannii. The alarming increase in the prevalence of CR-AB necessitates continuous screening and molecular characterization to appreciate the problem. The present study was performed to assess the prevalence and characterize carbapenemases among 206 CR-AB isolated from various clinical specimens collected from different intensive care units at Kasr Al-Aini Hospital.All isolates were confirmed to be A. baumannii by detection of the blaOXA-51-like gene. Molecular screening of 13 common Ambler class bla carbapenemases genes in addition to insertion sequence (IS-1) upstream OXA-23 was performed by using four sets of multiplex PCR, followed by identification using gene sequencing technology. Among the investigated genes, the prevalence of blaOXA-23, and blaOXA-58 were 77.7%, and 1.9%, respectively. The ISAba1 was detected in 10% of the blaOXA-23 positive isolates. The prevalence of metallo-β-lactamases (MBLs) studied; blaNDM-1, blaSPM, blaVIM, blaSIM-1 were 11.7%, 6.3%, 0.5%, and 0.5% respectively. One of class A; bla KPC was detected in 10.7% of the investigated isolates. blaOXA-24/40, blaIMP, blaGES, blaVEB and blaGIM were not detected in any of the studied isolates. Moreover, 18.4% of the isolates have shown to harbor two or more of the screened bla genes. We concluded that the most prevalent type of ß-lactamases genes among CR-AB isolates collected from Egyptian patients were blaOXA-23 followed by blaNDM-1 and blaKPC.Author summaryCarbapenem-resistant A. baumannii has become a real global health threat. The aim of the present study was to characterize and to assess the prevalence of carbapenemases among 206 CR-AB clinical isolates from Egyptian patients. We concluded that the most prevalent type of ß-lactamases genes among CR-AB isolates collected from Egyptian patients were blaOXA-23 followed by blaNDM-1 and blaKPC. In this study, ISAba1 was detected upstream 10% of blaOXA-23 positive isolates only which indicates that the spread of resistance among Acinetobacter isolates could be either chromosomal or plamid-mediated.

Distribution of carbapenem resistance mechanisms in clinical isolates of XDR Pseudomonas aeruginosa

2019 ◽  
Vol 38 (8) ◽  
pp. 1547-1552 ◽  
Author(s):  
Annalisa De Rosa ◽  
Nico T. Mutters ◽  
Claudio M. Mastroianni ◽  
Stefan J. Kaiser ◽  
Frank Günther
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates

scholarly journals Problematic clinical isolates of Pseudomonas aeruginosa from the university hospitals in Sofia, Bulgaria: current status of antimicrobial resistance and prevailing resistance mechanisms

2007 ◽  
Vol 56 (7) ◽  
pp. 956-963 ◽  
Author(s):  
Tanya Strateva ◽  
Vessela Ouzounova-Raykova ◽  
Boyka Markova ◽  
Albena Todorova ◽  
Yulia Marteva-Proevska ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Current Status ◽  
University Hospitals ◽  
Active Efflux ◽  
Genes Encoding

A total of 203 clinical isolates of Pseudomonas aeruginosa was collected during 2001–2006 from five university hospitals in Sofia, Bulgaria, to assess the current levels of antimicrobial susceptibility and to evaluate resistance mechanisms to antipseudomonal antimicrobial agents. The antibiotic resistance rates against the following antimicrobials were: carbenicillin 93.1 %, azlocillin 91.6 %, piperacillin 86.2 %, piperacillin/tazobactam 56.8 %, ceftazidime 45.8 %, cefepime 48.9 %, cefpirome 58.2 %, aztreonam 49.8 %, imipenem 42.3 %, meropenem 45.5 %, amikacin 59.1 %, gentamicin 79.7 %, tobramycin 89.6 %, netilmicin 69.6 % and ciprofloxacin 80.3 %. A total of 101 of the studied P. aeruginosa isolates (49.8 %) were multidrug resistant. Structural genes encoding class A and class D β-lactamases showed the following frequencies: bla VEB-1 33.1 %, bla PSE-1 22.5 %, bla PER-1 0 %, bla OXA-groupI 41.3 % and bla OXA-groupII 8.8 %. IMP- and VIM-type carbapenemases were not detected. In conclusion, the studied clinical strains of P. aeruginosa were problematic nosocomial pathogens. VEB-1 extended-spectrum β-lactamases appear to have a significant presence among clinical P. aeruginosa isolates from Sofia. Carbapenem resistance was related to non-enzymic mechanisms such as a deficiency of OprD proteins and active efflux.

P867 Carbapenem resistance mechanisms in Norwegian clinical isolates of Pseudomonas aeruginosa

2007 ◽  
Vol 29 ◽  
pp. S223-S224
Author(s):  
Ø. Samuelsen ◽  
L. Buarø ◽  
B. Aasnæs ◽  
C.G. Giske ◽  
B. Haldorsen ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates

scholarly journals Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) beta-lactamase enzymes in Acinetobacter baumannii

2020 ◽  
Author(s):  
Yuiko Takebayashi ◽  
Jacqueline Findlay ◽  
Kate J. Heesom ◽  
Philip J. Warburton ◽  
Matthew B. Avison ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Efflux Pump ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Beta Lactamase ◽  
Resistance Factors ◽  
Evolution Analysis ◽  
Ms Analysis ◽  
Additional Resistance

ABSTRACTObjectivesThis study aimed to measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterise the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC-MS/MS.MethodsDisc susceptibility and MIC broth microdilution tests were performed on ten clinical A. baumannii isolates and interpreted according to CLSI guidelines. Imipenem and meropenem MICs were evaluated for all oxaAb variants cloned into susceptible A. baumannii CIP70.10 and increased adeABC efflux pump gene expression BM4547 backgrounds, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC-MS/MS analysis.ResultsOxaAb(82), OxaAb(83), OxaAb(107), and OxaAb(110) carrying I129L and L167V substitutions increased carbapenem MICs when transferred into susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC-MS/MS analysis on the original clinical isolates showed no differences in expression levels of proteins commonly associated with carbapenem resistance.ConclusionsISAba1-driven overexpression of OxaAb variants with substitutions I129L and L167V confers carbapenem resistance with no need for additional resistance mechanisms.

scholarly journals Variability in carbapenemase activity of intrinsic OxaAb (OXA-51-like) β-lactamase enzymes in Acinetobacter baumannii

2020 ◽  
Author(s):  
Yuiko Takebayashi ◽  
Jacqueline Findlay ◽  
Kate J Heesom ◽  
Philip J Warburton ◽  
Matthew B Avison ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Acinetobacter Baumannii ◽  
Active Site ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Resistance Factors ◽  
Resistance Determinants ◽  
Evolution Analysis ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests

Abstract Objectives To measure the variability in carbapenem susceptibility conferred by different OxaAb variants, characterize the molecular evolution of oxaAb and elucidate the contribution of OxaAb and other possible carbapenem resistance factors in the clinical isolates using WGS and LC–MS/MS. Methods Antimicrobial susceptibility tests were performed on 10 clinical Acinetobacter baumannii isolates. Carbapenem MICs were evaluated for all oxaAb variants cloned into A. baumannii CIP70.10 and BM4547, with and without their natural promoters. Molecular evolution analysis of the oxaAb variants was performed using FastTree and SplitsTree4. Resistance determinants were studied in the clinical isolates using WGS and LC–MS/MS. Results Only the OxaAb variants with I129L and L167V substitutions, OxaAb(82), OxaAb(83), OxaAb(107) and OxaAb(110) increased carbapenem MICs when expressed in susceptible A. baumannii backgrounds without an upstream IS element. Carbapenem resistance was conferred with the addition of their natural upstream ISAba1 promoter. LC–MS/MS analysis on the original clinical isolates confirmed overexpression of the four I129L and L167V variants. No other differences in expression levels of proteins commonly associated with carbapenem resistance were detected. Conclusions Elevated carbapenem MICs were observed by expression of OxaAb variants carrying clinically prevalent substitutions I129L and L167V. To drive carbapenem resistance, these variants required overexpression by their upstream ISAba1 promoter. This study clearly demonstrates that a combination of IS-driven overexpression of oxaAb and the presence of particular amino acid substitutions in the active site to improve carbapenem capture is key in conferring carbapenem resistance in A. baumannii and other mechanisms are not required.

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