Background

In the last decade, incidences of carbapenem-resistant Acinetobacter baumannii have been increasingly reported worldwide. Consequently, A. baumannii was included in the World Health Organization’s new list of critical pathogens, for which new drugs are desperately needed. The objective of this research is to study the molecular epidemiology and antimicrobial susceptibility of clinical carbapenem-resistant A. baumannii isolated from Jordanian hospitals.

Methods

A total of 78 confirmed A. baumanni and 8 Acinetobacter spp. isolates were collected from 3 major hospitals in Jordan during 2018. Disc diffusion and microdilution methods were used to test their susceptibility against 19 antimicrobial agents. Multilocus sequence typing (MLST) was performed using the Pasteur scheme, followed by eBURST analysis for all isolates. PCR was used to detect β-lactam resistance genes, blaOXA-23-like, blaOXA-51-like and blaNDM-1.

Results

Of the 86 tested isolates, 78 (90.6%) exhibited resistance to carbapenems, while no resistance was recorded to tigecycline or polymyxins. Based on the resistance profiles, (10.4%) and (84.8%) of isolates were classified into multi-drug resistant (MDR) or, Extensively-drug resistant (XDR), respectively. The most prevalent carbapenems resistance genes among isolates were blaOXA-51-Like (89.5%), followed by blaOXA-23-Like (88.3%) and blaNDM-1 (10.4%). MLST revealed the presence of 19 sequence types (ST), belonging to 8 different international complexes. The most commonly detected clonal complex (CC) was CC2, representing 64% of all typed isolates.

Conclusions

This is the first study to report the clonal diversity of A. baumannii isolates in Jordan. A high incidence of carbapenem resistance was detected in the isolates investigated. In addition, our findings provided evidence for the wide spread of blaOXA-23-like harboring carbapenem-resistant A. baumannii belonging to CC2. The number of XDR isolates identified in this study is alarming. Thus, periodic surveillance and molecular epidemiological studies of resistance factors are important to improve treatment outcomes and prevent the spread of A. baumannii infections.