Molecular epidemiology characteristics and detecting transmission of carbapenemase-producing enterobacterales in southwestern China.

Background: To investigate the genotype and clinical characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains in southwest China and provide information on the treatment stopping the spread of the infection.

Methods: The clinical information of CRE isolates was collected from 19 hospitals in 12 cities across Sichuan Province, China, between June 2018 and April 2019. The isolates were detected by DNA sequencing of genes encoding carbapenem enzymes and multilocus sequence types (MLSTs).

Results: A total of 166 nonrepetitive CRE isolates were isolated during the study period from sputum, blood, urine, and other samples. Klebsiella pneumoniae carbapenemase (KPC) was dominant in Klebsiella pneumoniae (53.9%), followed by New Delhi metallo-β-lactamase (NDM) (42.1%). A total of 43 STs were detected. The most common ST of K. pneumoniae was ST11, and that of Escherichia coli was ST410. Pairwise single nucleotide polymorphism (SNP) distances and the likelihood of local transmission by epidemiology were plotted for each species. About 65% of these pairs had ≤ 20 pairwise SNPs.

Conclusion: A large number of CRE strains carried carbapenemase. Although NDM-ST12 K. pneumoniae should not be disregarded, KPC-ST11is the predominant strain. Thus, the possibility of transmission between E. coli and K. pneumoniae could not be ignored.