Nationwide Surveillance of Clinical Carbapenem-resistant Enterobacteriaceae (CRE) Strains in China.

The increasing incidence of carbapenem-resistant Enterobacteriaceae (CRE) - mediated hospital infections in China prompted a need to investigate the genetic basis of emergence of such strains. A nationwide survey was conducted in China covering a total of 1105 CRE strains collected from 25 geographical locales with results showing that acquisition of two carbapenemase genes, blaKPC-2 and blaNDM, was responsible for phenotypic resistance in 90% of the CRE strains tested (58% and 32% respectively), among which several major strain types, such as ST11 of K. pneumoniae and ST131/ST167 of E. coli, were identified, suggesting that dissemination of specific resistant clones is mainly responsible for emergence of new CRE strains. Prevalence of the fosA3 gene which mediates fosfomycin resistance, was high, while the colistin resistance determinant mcr-1 was rarely present in these isolates. Consistently, the majority of the blaNDM-bearing plasmids recoverable from the test strains belonged to IncX3, which contained a common core structure, blaNDM-blaMBL-trpF. Likewise, the core structure of ISKpn27-blaKPC-2-ISKpn2 was observed among plasmids harboring the blaKPC-2 gene, although they were genetically more divergent. In conclusion, the increasing prevalence of CRE strains in China is attributed to dissemination of conservative mobile elements carrying blaNDM or blaKPC-2 on conjugative and non-conjugative plasmids.

Zhang R ，Liu L ，Zhou H ，Chan EW ，Li J ，Fang Y ，Li Y ，Liao K ，Chen S ... -  《EBioMedicine》

Molecular characterization of carbapenem-resistant Enterobacteriaceae and emergence of tigecycline non-susceptible strains in the Henan province in China: a multicentrer study.

Yan WJ ，Jing N ，Wang SM ，Xu JH ，Yuan YH ，Zhang Q ，Li AL ，Chen LH ，Zhang JF ，Ma B ，Ma Q ，Li Y ... -  《-》

High prevalence and genomic characteristics of carbapenem-resistant Enterobacteriaceae and colistin-resistant Enterobacteriaceae from large-scale rivers in China.

The widespread presence of carbapenem-resistant Enterobacteriaceae (CRE) and mcr-positive Escherichia coli (MCREC) poses a huge threat to both animal and human health. River water environments are vital reservoirs of antibiotic resistance genes, however, the prevalence and characteristics of CRE and MCREC from large-scale rivers in China have not been reported. In the current study, we sampled 86 rivers from four cities in Shandong Province, China in 2021 and analyzed the prevalence of CRE and MCREC. The blaNDM/blaKPC-2/mcr-positive isolates were characterized with methods including PCR, antimicrobial susceptibility testing, conjugation, replicon typing, whole-genome sequencing and phylogenetic analysis. We found that the prevalence of CRE and MCREC in 86 rivers was 16.3% (14/86) and 27.9% (24/86), respectively and eight rivers carried both mcr-1 and blaNDM/blaKPC-2. A total of 48 Enterobacteriaceae isolates (10 ST11 Klebsiella pneumoniae with blaKPC-2, 12 blaNDM-positive E. coli and 26 MCREC carrying only mcr-1) were obtained in this study and 47 displayed multidrug resistance (MDR). Notably, 10 of the 12 blaNDM-positive E. coli isolates also harbored the mcr-1 gene. The blaKPC-2 gene was located within mobile element ISKpn27-blaKPC-2-ISKpn6 on novel F33:A-:B- non-conjugative MDR plasmids in ST11 K. pneumoniae. The dissemination of blaNDM was mediated by transferable MDR IncB/O plasmids or IncX3 plasmids while mcr-1 was primarily disseminated by highly similar IncI2 plasmids. Notably, these waterborne IncB/O, IncX3 and IncI2 plasmids were all highly similar to previously identified plasmids from animal and human isolates. A phylogenomic analysis revealed that the CRE and MCREC isolates from water environments might be derived from animals and trigger infections in humans. The high prevalence of CRE and MCREC in large-scale environmental rivers is alarming and needs sustained surveillance due to the potential risk for transmission to humans via the food chain (irrigation) or direct contact.

Guo CH ，Liu YQ ，Li Y ，Duan XX ，Yang TY ，Li FY ，Zou M ，Liu BT ... -  《-》

Rapid Increase in Prevalence of Carbapenem-Resistant Enterobacteriaceae (CRE) and Emergence of Colistin Resistance Gene mcr-1 in CRE in a Hospital in Henan, China.

The global spread of carbapenem-resistant Enterobacteriaceae (CRE) is one of the most severe threats to human health in a clinical setting. The recent emergence of plasmid-mediated colistin resistance gene mcr-1 among CRE strains greatly compromises the use of colistin as a last resort for the treatment of infections caused by CRE. This study aimed to understand the current epidemiological trends and characteristics of CRE from a large hospital in Henan, the most populous province in China. From 2014 to 2016, a total of 7,249 Enterobacteriaceae isolates were collected from clinical samples, among which 18.1% (1,311/7,249) were carbapenem resistant. Carbapenem-resistant Klebsiella pneumoniae and carbapenem-resistant Escherichia coli were the two most common CRE species, with Klebsiella pneumoniae carbapenemases (KPC) and New Delhi metallo-β-lactamases (NDM), respectively, responsible for the carbapenem resistance of the two species. Notably, >57.0% (n = 589) of the K. pneumoniae isolates from the intensive care unit were carbapenem resistant. Furthermore, blaNDM-5 and mcr-1 were found to coexist in one E. coli isolate, which exhibited resistance to almost all tested antibiotics. Overall, we observed a significant increase in the prevalence of CRE isolates during the study period and suggest that carbapenems may no longer be considered to be an effective treatment for infections caused by K. pneumoniae in the studied hospital.

Li Y ，Sun QL ，Shen Y ，Zhang Y ，Yang JW ，Shu LB ，Zhou HW ，Wang Y ，Wang B ，Zhang R ，Wang S ，Shen Z ... -  《-》

Phenotypic and Genotypic Characterization of Carbapenem-resistant Enterobacteriaceae: Data From a Longitudinal Large-scale CRE Study in China (2012-2016).

Wang Q ，Wang X ，Wang J ，Ouyang P ，Jin C ，Wang R ，Zhang Y ，Jin L ，Chen H ，Wang Z ，Zhang F ，Cao B ，Xie L ，Liao K ，Gu B ，Yang C ，Liu Z ，Ma X ，Jin L ，Zhang X ，Man S ，Li W ，Pei F ，Xu X ，Jin Y ，Ji P ，Wang H ... -  《-》