IngentaConnect Prevalence of Class 1 Integrons in Commensal Escherichia coli fro...

Authors: Phongpaichit, Souwalak¹; Liamthong, Sumalee²; Mathew, Alan G.³; Chethanond, Usa⁴

Source: Journal of Food Protection®, Volume 70, Number 2, February 2007 , pp. 292-299(8)

Publisher: International Association for Food Protection

Abstract:

Escherichia coli isolates (n = 617) from fecal samples of healthy and diarrheal pigs, pig farmers, and nonfarmers were analyzed for class 1 integrons. Three hundred ninety-two isolates (63.5%) were positive for class 1 integrons, based on the presence of intI1, with seventy-one of those isolates (11.5%) harboring all three conserved genes (intI1, qacEΔ1, and sul1) known to be associated with class 1 integrons. The presence of integrons was associated with isolate origin. Integrons were more prevalent in isolates from most pig groups than in isolates from pig farmers and nonfarmers. Selected integron-positive and integron-negative isolates were tested for resistance to 16 antimicrobials. All integron-positive swine isolates were multidrug resistant to at least three antimicrobial agents, demonstrating resistance to 14 different antibiotics that included sulphamethoxazole (100%), tetracycline (97.1%), ampicillin (92.8%), streptomycin (89.9%), trimethoprim-sulphamethoxazole (88.1%), nalidixic acid (60.9%), chloramphenicol (58.0%), kanamycin (55.1%), cephalothin (44.9%), gentamicin (39.1%), ciprofloxacin (33.3%), cefoxitin (8.7%), amoxicillin-clavulanic acid (5.8%), and amikacin (2.9%). All isolates were susceptible to ceftiofur and ceftriaxone. Forty-seven resistance patterns were observed among 69 integron-positive swine and swine farmer isolates. The most frequent pattern was tetracycline-ciprofloxacin-gentamicin-nalidixic acid-sulphamethoxazole-trimethoprim-sulphamethoxazole-kanamycin-ampicillin-streptomycin (10.1%), which was found in diarrheal and healthy pigs. This study shows that integrons and multidrug-resistant commensal bacteria are common and appear to be a significant aspect of microbial communities associated with pigs and humans in southern Thailand.

Document Type: Research article

Affiliations: 1: Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand 2: Department of Animal Science, University of Tennessee, Knoxville, Tennessee 37996, USA; Department of Biology, Faculty of Science and Technology, Nakhon Si Thammarat Rajabhat University, Nakhon Si Thammarat 80280, Thailand 3: Department of Animal Science, University of Tennessee, Knoxville, Tennessee 37996, USA 4: Department of Animal Science, Faculty of Natural Resources, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand

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Prevalence of Class 1 Integrons in Commensal Escherichia coli from Pigs and Pig Farmers in Thailand