Kyaw Phyoe Sunn. Phenotypic and genotypic characteristics of extended-spectrum beta-lactamase (ESBL) production and colistin-resistance in salmonella enterica and escherichia coli isolated from pigs and thier meat products in the border provinces between Thailand and Cambodia, Lao PDR and Myanmar. Master's Degree(Veterinary Science and Technology). Chulalongkorn University. Office of Academic Resources. : Chulalongkorn University, 2018.
Phenotypic and genotypic characteristics of extended-spectrum beta-lactamase (ESBL) production and colistin-resistance in salmonella enterica and escherichia coli isolated from pigs and thier meat products in the border provinces between Thailand and Cambodia, Lao PDR and Myanmar
Abstract:
A total of 809 samples of pig rectal swab from slaughterhouses (n=441) and pork from retail market (n=368) were collected in the border provinces among Thailand, Cambodia, Lao PDR and Myanmar between October 2016 and March 2017. The objective of this study was to determine resistance to extended-spectrum ß-lactams (ESBLs) and colistin in Salmonella enterica and Escherichia coli. A total of Salmonella (n=463) and E. coli (n=767) were collected and determined for the ESBL-production and for the Minimum Inhibitory Concentrations (MICs) of colistin and; the presence of ESBL gene and mcr gene. The results showed that the prevalence of Salmonella was highest in Cambodia (65.8%) and lowest in Myanmar (13.6%). Serovar Rissen was mostly observed. The prevalence of E. coli in pork was above 87% in all countries. ESBL-producing Salmonella (1.9%) and E. coli (6.3%) were detected at low level. Five bacterial isolates (1 Salmonella and 4 E. coli) were simultaneously resistant to colistin produced by ESBL enzymes. Among the ESBL genes tested, blaCTX-M and blaTEM genes were found in all countries. Twelve Salmonella and 68 E. coli isolates were positive to mcr-1 gene. One Salmonella and 31 E. coli isolates harbored mcr-3 gene. In addition, one Salmonella isolate from pork in Lao PDR carried both mcr-1 and blaCTX-M. One E. coli isolate from pigs in Thailand and one E. coli isolate from pig and pork in Cambodia belonged to mcr-3 and blaCTX-M. These findings demonstrated that pigs and pork serve as reservoirs for the next-generation cephalosporins and colistin-resistant Salmonella and E. coli. Monitoring of resistance to these antibiotics in food animals is needed.