Subject(s)
Cat Diseases , Dog Diseases , Animals , Cat Diseases/epidemiology , Cats , Cefotaxime/pharmacology , Dog Diseases/epidemiology , Dogs , Enterobacteriaceae , ThailandABSTRACT
This study was undertaken to assess the prevalence of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) among blow fly (Chrysomya megacephala) populations in Northern Thailand. Of 600 blow flies collected from rural (n = 400) and urban (n = 200) areas, 334 blow flies carried ESBL-EC (55.7%). Prevalence of ESBL-EC in blow flies captured from rural areas was significantly higher than that from urban region (72.5% vs. 22.0%, p < 0.001). Susceptibility tests revealed that 68.6% of ESBL-EC possessed multidrug-resistant phenotypes. Coresistance to gentamicin (85%) was common, while resistance to ciprofloxacin was relatively low (18.0%). Of the 334 isolates, 253 isolates (75.7%) harbored blaCTX-M, in which blaCTX-M group 1 was predominant (56.5%), followed by blaCTX-M group 9 (39.1%). Interestingly, a single isolate was found to carry blaCTX-M-5, which resided on the IncA/C conjugative plasmid. This is the first report of blaCTX-M-5 from Thailand and its first identification in blow fly. Pulsed field gel electrophoresis (PFGE) demonstrated high genetic diversity among ESBL-EC isolates. Nevertheless, identical and closely related PFGE profiles were detected among isolates within the same regions and the regions which are several kilometers apart, suggesting that clonal transmission has occurred. Moreover, epidemiologically related isolates were observed between ESBL-EC from blow flies and human intestinal tract. This study provides evidences that blow flies, C. megacephala, are important reservoirs for ESBL-EC and could potentially act as vectors for the spread of ESBL-EC in a Thai community.
Subject(s)
Anti-Bacterial Agents/pharmacology , Calliphoridae/microbiology , Escherichia coli/drug effects , Escherichia coli/genetics , beta-Lactamases/genetics , Animals , Drug Resistance, Multiple, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Escherichia coli/enzymology , Microbial Sensitivity Tests , Phenotype , Prevalence , Thailand/epidemiologyABSTRACT
Sixty-eight cefotaxime-resistant Escherichia coli isolates were recovered from different water environments in Northern Thailand. Isolates were mostly resistant to ceftazidime and aztreonam (>90%). The most common extended-spectrum ß-lactamase-encoding gene was blaCTX-M-group 1 (75%) followed by blaCTX-M-group 9 (13.2%). The co-existence of blaCTX-M and AmpC-type ß-lactamase genes was detected in 4 isolates (5.9%). Two E. coli isolates carrying blaCTX-M from canal and river water samples belonged to the phylogenetic group B2-ST131, which is known to be pathogenic. This is the first study on blaCTX-M and blaCMY-2-carrying E. coli and the emergence of ST131 from water environments in Thailand.
