Clonal Spread of Carbapenemase-Producing Enterobacteriaceae in a Region, China

Background: The increasing number of carbapenemase-producing Enterobacteriaceae (CPE) has become a serious problem globally. This study aimed to elucidate their geographically epidemiological characteristics. Results A total of 930 phenotypically confirmed carbapenem-resistant Enterobacteriaceae (CRE) isolates collected from 19 hospitals were genotypically characterised. K.pneumoniae (KP) and E.coli isolates were 785 (85.14%) and 96 (10.41%) among 922 CPE isolates. Two major carbapenemase genes KPC-2 and NDM in CPE isolates accounted for 84.6% (n = 780) and 13.77% (n = 127). ST11 comprised 86.83% (633/729) of KPC-2 KP isolates. The wzi typing method could further subdivide ST11 KP group into at least five subgroups, among which wzi 209 (69.83%, 442/633) was the most frequently isolated, followed by wzi 141 (25.28%, 160/633). Conjugation assays showed that high conjugation rates were observed in CPE (15.24%, 32/210) for NDM plasmids, but relatively low (8.1%, 17/210) for KPC-2 plasmids. No associations between the rates of antibiotics consumption and CPE prevalence were observed. The number of intra-hospital and inter-hospital transfers of CPE patients increased gradually from 18 (17.82%, 101) and 12 (11.88%, 101) in 2015 to 63 (30.73%, 205) and 51 (24.88%, 205) in 2018 ( p  = 0.016 and p  = 0.008), respectively. Evidence-based measures could effectively reduce the prevalence of ST11- wzi 209 clone but failed to control the dissemination of ST11- wzi 141 KP clone. Conclusions Clonal spread of CPE, especially KPC-2 ST11 KP was the key factor contributing to the CPE increase in the region. Continued vigilance for the importations should be maintained. Coordinated regional interventions are urgently needed to reduce CPE threat.