scholarly journals Identification and Isolation of Insertion Sequences, in Carbapenem Resistant Clinical Isolates of Acinetobacter baumannii from Tehran Hospitals

2017 ◽  
Vol 11 (6) ◽  
Author(s):  
Mina Owrang ◽  
Fatemeh Fallah ◽  
Shiva Irani ◽  
Mohammad Rahbar ◽  
Gita Eslami
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolates ◽  
Insertion Sequences ◽  
Carbapenem Resistant

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.

scholarly journals Colistin heteroresistance in carbapenem-resistant Acinetobacter baumannii clinical isolates from a Thai university hospital

2020 ◽  
Vol 36 (7) ◽  
Author(s):  
Khin Thet Thet ◽  
Kamonwan Lunha ◽  
Arpasiri Srisrattakarn ◽  
Aroonlug Lulitanond ◽  
Ratree Tavichakorntrakool ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolates ◽  
University Hospital ◽  
Carbapenem Resistant ◽  
Thai University

scholarly journals Population Structure Analysis of Carbapenem-Resistant Acinetobacter baumannii Clinical Isolates from Brazil Reveals Predominance of Clonal Complexes 1, 15, and 79

2016 ◽  
Vol 60 (4) ◽  
pp. 2545-2547 ◽  
Author(s):  
Carlos Henrique Camargo ◽  
Monique Ribeiro Tiba ◽  
Marta Regina Saes ◽  
Francielli Mahnic de Vasconcellos ◽  
Luis Fernando dos Santos ◽  
...  
Keyword(s):  
Population Structure ◽  
Acinetobacter Baumannii ◽  
Gel Electrophoresis ◽  
Multilocus Sequence Typing ◽  
Clonal Complex ◽  
Pulsed Field Gel Electrophoresis ◽  
Clinical Isolates ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Population Structure Analysis

ABSTRACTThe population structure of 71 carbapenem-resistantAcinetobacter baumanniiclinical isolates from several hospitals in Brazil was investigated by ApaI pulsed-field gel electrophoresis,blaOXA-51-like subtyping, and multilocus sequence typing (Institute Pasteur scheme). In addition to the predominance of strains carryingblaOXA-23, we detected the presence ofblaOXA-72andblaOXA-231. We observed a predominance of clonal complex 1 (CC1), CC15, and CC79 and representative strains of the worldwide-disseminated international clone I.

Carbapenem-susceptible Acinetobacter baumannii carrying the ISAba1 upstream blaOXA-51-like gene in Porto Alegre, southern Brazil

2012 ◽  
Vol 141 (2) ◽  
pp. 330-333 ◽  
Author(s):  
M. PAGANO ◽  
A. F. MARTINS ◽  
A. B. M. P. MACHADO ◽  
J. BARIN ◽  
A. L. BARTH
Keyword(s):  
Antimicrobial Resistance ◽  
Acinetobacter Baumannii ◽  
Clinical Isolates ◽  
High Morbidity ◽  
Southern Brazil ◽  
Porto Alegre ◽  
Integrase Gene ◽  
Carbapenem Resistant ◽  
High Prevalence ◽  
Class 1

SUMMARYOver the last decade, Acinetobacter baumannii resistant to carbapenems has emerged in many medical centres and is commonly associated with high morbidity and mortality. We investigated potential mechanisms contributing to antimicrobial resistance of 58 clinical isolates of A. baumannii collected during a prolonged city-wide outbreak in five different hospitals in southern Brazil. The integrase gene was detected in 51 (87·9%) isolates of which 36 harboured class 2 integrons alone and 14 had both class 1 and 2 integrons; all carbapenem-resistant isolates displayed class 2 integrons. ISAba1 was found upstream of blaOXA-23-like only in isolates resistant to carbapenems; however, ISAba1 upstream of blaOXA-51-like was present in both susceptible and resistant isolates. This is the first report of a high prevalence of class 2 integrons in A. baumannii in southern Brazil. Moreover, our study suggests that ISAba1/blaOXA-51-like alone is insufficient to confer resistance to carbapenems.

scholarly journals Genomic Analysis of Carbapenem-Resistant Acinetobacter baumannii Isolates Belonging to Major Endemic Clones in South America

2020 ◽  
Vol 11 ◽  
Author(s):  
Carolina Silva Nodari ◽  
Rodrigo Cayô ◽  
Ana Paula Streling ◽  
Felipe Lei ◽  
Julia Wille ◽  
...  
Keyword(s):  
South America ◽  
Acinetobacter Baumannii ◽  
Outer Membrane Proteins ◽  
Acquired Resistance ◽  
Clinical Isolates ◽  
Efflux System ◽  
Illumina Platform ◽  
Synonymous Mutations ◽  
Resistance Determinants ◽  
Carbapenem Resistant

Carbapenem-resistant Acinetobacter baumannii (CRAB) are emerging worldwide. In South America, clinical isolates presenting such a phenotype usually do not belong to the globally distributed international clone 2 (IC2). The majority of these isolates are also resistant to multiple other antimicrobials and are often designated extremely drug-resistant (XDR). The aim of this study was to characterize the resistance mechanisms presented by 18 carbapenem-resistant A. baumannii isolates from five different Brazilian hospitals. Species identification was determined by rpoB sequencing, and antimicrobial susceptibility was determined by broth microdilution. Isolates were submitted to whole genome sequencing using Illumina platform and genetic similarity was determined by PFGE, MLST, and cgMLST. Genome analysis was used to identify intrinsic and acquired resistance determinants, including mutations in the AdeRSABC efflux system and in outer membrane proteins (OMPs). All isolates were identified as A. baumannii and grouped into 4 pulsotypes by PFGE, which belonged to clonal complexes (CC) 15Pas/103Ox (n = 4) and 79Pas/113Ox (n = 14), corresponding to IC4 and IC5, respectively. High MIC values to carbapenems, broad-spectrum cephalosporins, amikacin, and ciprofloxacin were observed in all isolates, while MICs of ampicillin/sulbactam, gentamicin, and tigecycline varied among the isolates. Minocycline was the most active antimicrobial agent tested. Moreover, 12 isolates (66.7%) were considered resistant to polymyxins. Besides intrinsic OXA-51 and ADC variants, all isolates harbored an acquired carbapenem-hydrolyzing class D β-lactamase (CHDL) encoding gene, either blaOXA–23 or blaOXA–72. A diversity of aminoglycoside modifying enzymes and resistance determinants to other antimicrobial classes were found, as well as mutations in gyrA and parC. Non-synonymous mutations have also been identified in the AdeRSABC efflux system and in most OMPs, but they were considered natural polymorphisms. Moreover, resistance to polymyxins among isolates belonging to IC5 were associated to non-synonymous mutations in pmrB, but no known polymyxin resistance mechanism was identified in isolates belonging to IC4. In conclusion, A. baumannii clinical isolates belonging to South America’s major clones present a myriad of antimicrobial resistance determinants. Special attention should be paid to natural polymorphisms observed in each clonal lineage, especially regarding non-synonymous mutations in constitutive genes associated with distinct resistance phenotypes.

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