The emergence of a novel sequence type of MDR Acinetobacter baumannii from the intensive care unit of an Egyptian tertiary care hospital

Background and aim of work: Acinetobacter baumannii is known for nosocomial outbreaks worldwide. In this study, we aimed to investigate the antibiotic susceptibility patterns and the clonal relationship of A. baumannii isolates from the intensive care unit (ICU) of an Egyptian hospital. Methods: In the present study, 50 clinical isolates of multidrug resistant (MDR)-A. baumannii were obtained from patients admitted into the ICU from June to December 2015. All isolates were analyzed for antimicrobial susceptibilities. Multiplex PCR was performed to detect genes encoding oxacillinase genes (bla(OXA-51)-like, bla(OXA-23)-like, bla(OXA-24)-like, and bla(OXA-58)-like). Multilocus sequence typing (MLST) based on the seven-gene scheme (gltA, gyrB, gdhB, recA, cpn60, gpi, rpoD) was used to examine these isolates. Results: All A. baumannii clinical isolates showed the same resistance pattern, characterized by resistance to most common antibiotics including imipenem (MIC >= 8 mu/mL), with the only exception being colistin. Most isolates were positive for bla(OXA-51)-like and bla(OXA-23)-like (100 and 96%, respectively); however, bla(OXA-24)-like and bla(OXA-58)-like were not detected. MLST analysis identified different sequence types (ST195, ST208, ST231, ST441, ST499, and ST723) and a new sequence type (ST13929) with other sporadic strains. Conclusions: MDR A. baumannii strains harboring bla(OXA-23)-like genes were widely circulating in this ICU. MLST was a powerful tool for identifying and epidemiologically typing our strains. Strict infection control measures must be implemented to contain the worldwide spread of MDR A. baumannii in ICUs.