Clonal diversity of Acinetobacter baumannii clinical isolates revealed by a snapshot study

Abstract

Abstract Background Acinetobacter baumannii is a notorious opportunistic pathogen mainly associated with hospital-acquired infections. Studies on the clonal relatedness of isolates could lay the foundation for effective infection control. A snapshot study was performed to investigate the clonal relatedness of A. baumannii clinical isolates in our local settings. Results Among 82 non-repetitive Acinetobacter spp. clinical isolates that were recovered during a period of four days in 13 hospitals in Sichuan, Southwest China, 67 isolates were identified as A. baumannii. Half of the 67 A. baumannii isolates were non-susceptible to carbapenems. bla OXA-23 was the only acquired carbapenemase gene detected, present in 40 isolates including five carbapenem-susceptible ones. The isolates belonged to 62 pulsotypes determined by PFGE and 31 sequence types (ST) by multi-locus sequence typing. Forty-three isolates belonged to the globally-disseminated clonal complex 92, among which ST75, ST92 and ST208 were the most common sequence types. Conclusions Clinical isolates of A. baumannii were diverse in clonality in this snapshot study. However, most of the isolates belonged to the globally-distributed clonal complex CC92. ST75, ST92 and ST208 were the most common types in our region. In particular, ST208 might be an emerging lineage carrying bla OXA-23.