Molecular characterization of multidrug-resistant ESKAPEE pathogens from clinical samples in Chonburi, Thailand (2017-2018).

BACKGROUND: ESKAPEE pathogens Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli are multi-drug resistant (MDR) bacteria that present increasing treatment challenges for healthcare institutions and public health worldwide. METHODS: 431 MDR ESKAPEE pathogens were collected from Queen Sirikit Naval Hospital, Chonburi, Thailand between 2017 and 2018. Species identification and antimicrobial resistance (AMR) phenotype were determined following CLSI and EUCAST guidelines on the BD Phoenix System. Molecular identification of antibiotic resistant genes was performed by polymerase chain reaction (PCR), real-time PCR assays, and whole genome sequencing (WGS). RESULTS: Of the 431 MDR isolates collected, 1.2% were E. faecium, 5.8% were S. aureus, 23.7% were K. pneumoniae, 22.5% were A. baumannii, 4.6% were P. aeruginosa, 0.9% were Enterobacter spp., and 41.3% were E. coli. Of the 401 Gram-negative MDR isolates, 51% were carbapenem resistant, 45% were ESBL producers only, 2% were colistin resistance and ESBLs producers (2%), and 2% were non-ESBLs producers. The most prevalent carbapenemase genes were blaOXA-23 (23%), which was only identified in A. baumannii, followed by blaNDM (17%), and blaOXA-48-like (13%). Beta-lactamase genes detected included blaTEM, blaSHV, blaOXA, blaCTX-M, blaDHA, blaCMY, blaPER and blaVEB. Seven E. coli and K. pneumoniae isolates showed resistance to colistin and carried mcr-1 or mcr-3, with 2 E. coli strains carrying both genes. Among 30 Gram-positive MDR ESKAPEE, all VRE isolates carried the vanA gene (100%) and 84% S. aureus isolates carried the mecA gene. CONCLUSIONS: This report highlights the prevalence of AMR among clinical ESKAPEE pathogens in eastern Thailand. E. coli was the most common MDR pathogen collected, followed by K. pneumoniae, and A. baumannii. Carbapenem-resistant Enterobacteriaceae (CRE) and extended spectrum beta-lactamases (ESBLs) producers were the most common resistance profiles. The co-occurrence of mcr-1 and mcr-3 in 2 E. coli strains, which did not affect the level of colistin resistance, is also reported. The participation of global stakeholders and surveillance of MDR remain essential for the control and management of MDR ESKAPEE pathogens.

First Report: Colistin Resistance Gene mcr-3.1 in Salmonella enterica Serotype Choleraesuis Isolated from Human Blood Sample from Thailand.

This study describes the first finding of Salmonella enterica serotype Choleraesuis (Salmonella Choleraesuis) isolate harboring mobile colistin resistance (mcr)-3.1 obtained from human blood sample. The clinical relevant blood sample was collected during October 2018. The phenotypic identification and antimicrobial susceptibility testing (AST) were studied by using automate microbiology platform (Phoenix M50, BD), and in-depth characterization by whole genome sequencing. The phenotypic identification was reported Salmonella Choleraesuis. AST result demonstrated that this isolate had high minimum inhibitory concentrations (MICs) against colistin, fluoroquinolone, and cephalosporin III and IV, which are first-line antibiotic treatment choices for Gram-negative bacterial pathogen infections. This Salmonella Choleraesuis is harboring mcr-3.1 and presented a diversity carbapenemase including blaTEM and blactx-m-55. Regarding the multilocus sequence typing result, this Salmonella presented ST139 that related to the Choleraesuis variant sensu stricto. Swine is not the host specific for the Salmonella Choleraesuis since it also causes enteric and other diseases in human. Hence, the presence of the mobile plasmid colistin mcr-3.1 resistant gene in human sample is resulting to the public health concerns due to the fact that it is enable to transmit to other hosts and distribute into an environment.