Molecular Epidemiology of Carbapenem-Resistant Acinetobacter baumannii Isolates in the Gulf Cooperation Council States: Dominance of OXA-23-Type Producers

Abstract

The molecular epidemiology and mechanisms of resistance of carbapenem-resistant Acinetobacter baumannii (CRAB) were determined in hospitals in the countries of the Gulf Cooperation Council (GCC), namely, Saudi Arabia, United Arab Emirates, Oman, Qatar, Bahrain, and Kuwait. Isolates were subjected to PCR-based detection of antibiotic-resistance genes and repetitive sequence-based PCR (rep-PCR) assessments of clonality. Selected isolates were subjected to multilocus sequence typing (MLST). 117 isolates found resistant to carbapenem antibiotics (either imipenem or meropenem) were investigated. All isolates were positive for OXA-51. The most common carbapenemases were of the OXA-23-type in 107 isolates followed by OXA-40-type (OXA-24-type) in 5 isolates; 3 isolates were found to carry the ISAba1 element upstream of bla_OXA-51-type. No OXA-58-type, NDM-type, VIM-type, or IMP-type producers were detected. Multiple clones were detected with 16 clusters of clonally related CRAB. Some clusters involved hospitals in different countries. MLST analysis of 15 representative isolates from different clusters identified seven different sequence types; ST195, ST208, ST229, ST436, ST450, ST452 and ST499, as well as three novel STs. The vast majority of the isolates in this study (84%) were associated with healthcare exposure. Awareness of multidrug resistant organisms in GCC countries has important implications for optimizing infection control practices, establishing antimicrobial stewardship programs within hospital, community, and agricultural settings, and reemphasizing the need for establishing regional active surveillance systems. This will help to control the spread of CRAB in the Middle East and in hospitals accommodating transferred patients from this region.