Emergence of Carbapenem-Resistant Acinetobacter baumannii ST195 Harboring bla OXA-23 Isolated from Bacteremia in Hong Kong

Aims: The aim of the study was to analyze the epidemiology of Acinetobacter baumannii and investigate the genetic characteristics of carbapenem-resistant A. baumannii (CRAB) isolates isolated from blood cultures in a regional hospital in Hong Kong. Results: Twenty blood culture isolates were collected from a regional hospital in Hong Kong from 2014 to 2017. Twenty isolates were grouped into five existing sequence types (STs) and five new STs within the following prevalence: ST195 was predominant with a prevalence of 45% ( n = 9), followed by ST373 and ST447 (10%; n = 2 each), and ST176 and ST345 (5%; n = 1 each). Resistance to carbapenem antibiotics was 55% ( n = 11). Six carbapenem-resistant isolates harbored bla OXA-23 genes and IS Aba1 mobile elements. Polymerase chain reaction confirmed that IS Aba 1 is located upstream to the bla OXA-23 genes, suggesting an association between IS Aba1 and bla OXA-23 genes with carbapenem resistance. Conclusion: This study is the first to report the emergence of CRAB ST195 harboring bla OXA-23 in Hong Kong.