Purpose: The aim of this study was to investigate whether domestic and imported fresh produce play a role as a carrier of ESBL/AmpC-producing Enterobacteriaceae.
Methods: Three hundred and sixty produce were purchased and analyzed for ESBL/AmpC-producing Enterobacteriaceae. Enterobacteriaceae isolated from produce was screened with a cefotoxime (1 mg/ml). Selected isolates were screened for ESBLs and AmpC production by Kirby Bauer disk diffusion method and suspected isolates were subjected to double disk synergy. ESBL was tested by using cefpodoxime and ceftriaxone antibiotic discs. Amoxicillin plus clavulanic acid in combination with cefpodoxime and ceftriaxone were used. Cefoxitin discs and Amp C disk tests were used to test for Amp C producers and confirmation of presumptive isolates, respectively. Colonies from produce were also tested for resistance with other antibiotics: cefoxitin, amikacin, azrithromycin, erythromycin, streptomycin, vancomycin, cefotaxime, and ciprofloxacin.
Results: Twenty-five isolates (16.6%) and twelve (4.6%) isolates out of 150 were ESBL and AmpC producers, respectively. Our results indicate that domestic and imported produce were positive for ESBL/AmpC-producing Enterobacteriaceae. Majority of the isolates (82%) demonstrated resistance to streptomycin (95.3%), erythromycin (80%), vancomycin (63.5%), and were statistically higher (P < 0.05) than in other antibiotics evaluated. Other antibiotics indicated resistance of less than 20%.
Significance: These findings suggest that domestic and imported produce in grocery stores is contaminated with ESBL/AmpC- producing Enterobacteriaceae. Improving hygiene, limited use of antibiotics, and post-harvest controls for foodborne pathogens in farms would be a measure to control the dissemination of ESBL/AmpC- Enterobacteriaceae.