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

Leila Vali,Khaled Al Obaid,Khadija Dashti,Ali A Dashti,Andrés F Opazo-Capurro,Benjamin A Evans

doi:10.3389/fmicb.2015.00743

Abstract

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 (MDR) 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 MDR 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 three 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. Multilocus-sequence typing (MLST) analysis of the 33 A. baumannii isolates identified 20 different STs, of which six (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. Pulsed-field gel electrophoresis 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 ward simultaneously.

Highlights

Acinetobacter baumannii is one of the most important opportunistic pathogens that causes outbreaks in hospitals and serious health care associated complications in critically ill patients
In the case of infections caused by multidrug resistant (MDR) strains, tigecycline and colistin are recommended as the last therapeutic options either alone or in combination therapy (Talbot et al, 2006)
In the current study we report on the diversity of the clinical MDR A. baumannii isolated from one of the largest governmental hospitals in Kuwait

Summary

Introduction

Acinetobacter baumannii is one of the most important opportunistic pathogens that causes outbreaks in hospitals and serious health care associated complications in critically ill patients. The ability to acquire multiple antibiotic resistance genes and to survive in inanimate environments are important characteristics of this nosocomial pathogen (Corbella et al, 2000). The guidelines for the antimicrobial therapy for the treatment of Acinetobacter infections comprise of broad spectrum cephalosporins, the β-lactamase inhibitor sulbactam, Diversity of MDR A. baumannii quinolones, carbapenems, amikacin, doxycycline, and minocycline. In the case of infections caused by multidrug resistant (MDR) strains, tigecycline and colistin are recommended as the last therapeutic options either alone or in combination therapy (Talbot et al, 2006). Some A. baumannii isolates have become resistant to almost all the currently available antibiotics including colistin (Magiorakos et al, 2012). Acquisition of resistance to colistin is mostly due to modifications of the lipopolysaccharide (LPS) biosynthesis pathway (Potron et al, 2015)

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