Emergence of Carbapenem-Resistant ST244, ST292, and ST2446 Clones in Burn Patients in Yunnan Province.

INTRODUCTION

The prevalence of carbapenem-resistant is increasing persistently, particularly in burn ward isolates. Here, we investigate the prevalence of carbapenem-resistant in a burn ward of a provincial-level hospital at Kunming, Yunnan province, China.

METHODS

A total of 118 strains were isolated from 57 hospitalized patients, and their MICs were measured. Carbapenem-resistant isolates were selected for multilocus sequence typing (MLST). Carbapenem-resistance mechanisms were identified by examining carbapenemase genes and OprD protein and Carba-NP testing. Representative isolates were further characterized by de novo sequencing for carbapenemase molecular background.

RESULTS

Among 118 isolates, 54 (54/118,45.8%) were carbapenem-resistant , and 3 genotypes were found (ST292, ST244, and ST2446). Non-carbapenemase-producing ST292 was the most prevalent ST, followed by ST2446 and ST244. A novel 13-bp deletion was found in the ST292 clone, which formed the truncated outer membrane protein and may cause carbapenem resistance. ST244 and ST2446 harbored and , respectively. is located in a megaplasmid, together with / and lead to extensive drug resistance. ST2446 contains a carbapenem-resistant gene on the chromosome and is acquired by a novel gene cassette array () of class 1 integron.

DISCUSSION

For the first time, ST244, ST292 and ST2446 are reported emerging in burn patients, with distinctive carbapenem-resistance mechanisms, respectively. The obtained results highlight the need to surveillance carbapenem-resistant isolates in burn patients.