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-ß-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.

Prevalence and phenotypic characterization of carbapenem-resistant Klebsiella pneumoniae strains recovered from sputum and fecal samples of ICU patients in Zhejiang Province, China.

OBJECTIVE: To understand the prevalence and transmission of carbapenem-resistant Klebsiella pneumoniae (CRKP) in ICU patients in Zhejiang Province, China, and determined the genetic and phenotypic characteristics of these CRKP strains. MATERIALS AND METHODS: A total of 202 ICU patients from eight tertiary hospitals were recruited and 55 non-duplicate CRKP strains were collected during July and August in 2017. These strains were subjected to determination of MICs, carriage of carbapenemase genes and tet(A) variants, PFGE, MLST and virulence potential using G. mellonella larvae infection model. RESULTS: A total of 55 CRKP strains were recovered from 42 patients, representing a carriage rate of 20.8%. CRKP strains were recovered from both the intestinal and respiratory tract of 13 patients. Importantly, strains isolated from sputum and fecal samples often displayed identical PFGE profiles, suggesting that CRKP may also colonize the respiratory tract. The most dominant ST type of these CRKP strains was ST11, accounting for 78% (43/55) of the test strains. The majority of CRKP strains were resistant to multiple antibiotics, with the exception of tigecycline and ceftazidime/avibactam. Interestingly, 32 strains were found to harbor the tet(A) variant, which is known to confer reduced tigecycline susceptibility. Assessment of the virulence potential of these CRKP strains by string test showed that results were negative for 53 of the 55 test strains. However, further assessment of virulence potential using a G. mellonella larvae infection model showed that CRKP isolated from sputum consistently exhibited a higher virulence level than strains recovered from fecal samples. CONCLUSION: CRKP is highly prevalent in ICU patients in Zhejiang Province with strains isolated from respiratory exhibiting higher virulence potential than those from GI tract. These data provide essential insight into development of new infection control measures to halt the transmission of CRKP in clinical settings.