Fecal carriage and molecular epidemiology of carbapenem-resistant Enterobacteriaceae isolated from children in Henan Province, China

Abstract

Abstract Background: This study sought to investigate the carrier rate of intestinal carbapenem-resistant Enterobacteriaceae (CRE) in children, in Henan Province. Methods: In a prospective study, 1019 non-repetitive fecal samples were consecutively obtained from outpatient (n = 710) and inpatient children (n = 309). Isolates were cultured in MacConkey medium from fecal specimens, and matrix-assisted laser desorption ionization-time of flight mass spectrometry was used for strain identification. Imipenem and meropenem E-test strips were used for CRE screening, and antimicrobial susceptibility was determined using VITEK-2 AST GN335. Resistance genes and multilocus sequence types were identified by whole-genome sequencing. Results: The overall CRE colonization rates in children were 1.5%. Five CRE were isolated from outpatient children with a colonization rate of 0.7%. Strains were mainly NDM-5 producing Escherichia coli, which belonged to ST410, ST1193, and ST10885. Ten CRE were isolated from hospitalized children with a colonization rate of 3.2%, mainly NDM-producing K. pneumoniae and NDM-5-producing E. coli. The NDM-producing K. pneumoniae belonged to subtypes, including ST70, ST357, ST491, and ST2864. The blaNDM-5 gene was the major carbapenemase gene harbored by gastrointestinal CRE strains, followed by blaKPC-2. Furthermore, extended-spectrum b-lactamase genes (blaCTX-M, blaTEM, and blaSHV) and AmpC genes (blaDHA-1 and blaCMY-2) were detected. All CRE strains showed high resistance to most of the routinely used antibiotics, except for polymyxin B and tigecycline. Conclusions: The intestinal CRE colonization rate of children in Henan is very low, and the production of blaNDM carbapenemase was the main mechanism of carbapenem resistance. Different from the main epidemic types of clinically isolated CRE strains, the types of CRE colonizing isolates show diversity.