ABSTRACT
BACKGROUND: The increasing incidence and prevalence of carbapenem-resistant Enterobacter cloacae complex (CREC) poses great challenges to infection prevention and disease treatment. However, much remains unknown about the clinical characteristics of CREC isolates. Our objective was to characterize antimicrobial resistance and, carbapenemase production in CREC with 36 CREC isolates collected from a tertiary hospital in Shandong, China. RESULTS: Three types of carbapenemases (NDM, IMP and VIM) were detected in these isolates. Among them, NDM carbapenemases were most prevalent, with a 61.2% (22/36) detection rate for NDM-1, 27.8% (10/36) for NDM-5 and 2.8% (1/36) for NDM-7. IMP-4 was found in two isolates and VIM-1 in only one isolate. The MLST analysis identified 12 different sequence types (STs), of which ST171 (27.8%) was the most prevalent, followed by ST418 (25.0%). ST171 isolates had significantly higher rates of resistance than other STs to gentamicin and tobramycin (Ps < 0.05), and lower rates of resistance to aztreonam than ST418 and other STs (Ps < 0.05). Among 17 carbapenemase-encoding genes, the blaNDM-5 gene was more frequently detected in ST171 than in ST418 and other isolates (Ps < 0.05). In contrast, the blaNDM-1 gene was more frequently seen in ST418 than in ST171 isolates. One novel ST (ST1965) was identified, which carried the blaNDM-1 gene. CONCLUSION: NDM-5 produced by ST171 and NDM-1 carbapenemase produced by ST418 were the leading cause of CREC in this hospital. This study enhances the understanding of CREC strains and helps improve infection control and treatment in hospitals.
Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Enterobacteriaceae Infections , Humans , Enterobacter cloacae/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Carbapenems/pharmacology , Tertiary Care Centers , Multilocus Sequence Typing , Enterobacteriaceae Infections/epidemiology , beta-Lactamases/genetics , Bacterial Proteins/genetics , Carbapenem-Resistant Enterobacteriaceae/genetics , China/epidemiology , Microbial Sensitivity TestsABSTRACT
Epidemiological characteristics and molecular features of carbapenem-resistant Enterobacter (CR-Ent) species remain unclear in China. In this study, we performed a genomic study on 92 isolates from Enterobacter-caused infections from a multicenter study in China. Whole genome sequencing (WGS) was used to determine the genome sequence of 92 non-duplicated CR-Ent strains collected from multiple tertiary health centres. The precise species of Enterobacter strains were identified by average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH). Molecular features of high-risk CR-Ent sequence type (ST) lineages and carbapenemase-encoding plasmids were determined. The result revealed that the most common human-source CR-Ent species in China was E. xiangfangensis (66/92, 71.93%), and the proportion of carbapenemase-producing Enterobacter (CP-Ent) in CR-Ent was high (72/92, 78.26%) in comparison to other global regions. Furthermore, ST171 and ST116 E. xiangfangensis were the major lineages of CP-Ent strains, and ST171 E. xiangfangensis was more likely to cause infections in older patients. Genomic analysis also highlighted the likelihood of intra-hospital/inter-hospital clonal transmission of ST171 and ST116 E. xiangfangensis. In addition, the blaNDM-harbouring IncX3-type plasmid was identified as the prevalent carbapenemase-encoding plasmid carried by CR-Ent strains, and was experimentally confirmed to be able to self-transfer with high frequency. This study detailed the genomic and clinical characteristics of CR-Ent in China in the form of multicenter for the first time. The high risk of carbapenemase-producing ST171 and ST116 E. xiangfangensis, and the blaNDM-harbouring IncX3-type plasmid were detected and emphasized.
Subject(s)
Carbapenem-Resistant Enterobacteriaceae , Enterobacter , Enterobacteriaceae Infections , Aged , Humans , Bacterial Proteins/genetics , beta-Lactamases/genetics , Carbapenem-Resistant Enterobacteriaceae/genetics , Carbapenem-Resistant Enterobacteriaceae/isolation & purification , China/epidemiology , Enterobacter/genetics , Enterobacter/isolation & purification , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae Infections/microbiology , Genomics , Microbial Sensitivity Tests , Plasmids/geneticsABSTRACT
We report the complete genome sequence and analysis of an invasive Corynebacterium diphtheriae strain that caused endocarditis in Rio de Janeiro, Brazil. It was selected for sequencing on the basis of the current relevance of nontoxigenic strains for public health. The genomic information was explored in the context of diversity, plasticity and genetic relatedness with other contemporary strains.
