Local characteristics of molecular epidemiolgy of Acinetobacter baumannii in Jilin province (northeast China).

A. Baumannii is an opportunistic nosocomial pathogen which has severe antibiotic resistance. However, the epidemiology is less clearly understood in Jilin province and China. Thus, 89 A. baumannii isolates from a single hospital in Jilin province between 2013-2017 were performed by MLST. In order to better understanding of the epidemiology of Jilin isolates, Chinese strains originated from other domestic regions and worldwide isolates in MLST database were analyzed by silico phylogenetic tools together. A total of 22 STs in Jilin were identified, and 10 STs were found to be novel. The top three predominant sequence types are ST195 (n = 34, 38.2%), ST208 (n = 14, 15.7%) and ST540 (n = 13, 14.6%). ST369 is predicted to be group founder and ST195, ST540 are subgroup founders of the majority STs in Jilin Province. Some newly discovered singletons showed close relationship with strains from other countries, which suggest that nation-cross transmission is one of important origin of Jilin strains. The majority of Jilin STs showed clonality and close relationship with the majorities from other regions of China. But occupation of individual STs in Jilin were different from that of other domestic regions. The aggregation trend and genetic relationship proved that predominant Jilin STs continue to mutate during transmission. Drug resistance facilitated transmission of Jilin A.baumannii isolates because more than 94% of isolates are resistant to at least one carbapenem and the STs with strong resistance to carbapenems usually has more isolates. In conclusion, high diversity and different occupation of STs, and occupation of novel STs proved that epidemiology of A. baumannii in Jilin has special regional characteristics, and drug resistance facilitated transmission of domestic strains and foreign strains.