Class 1 integrons and multidrug resistance among Escherichia coli isolates from human stools.
Three hundred and eighteen Escherichia coli isolates from stools of healthy volunteers and outpatients from a major university hospital in southern Thailand were tested for the presence of class 1 integrons using multiplex-PCR and for their susceptibility against 12 antimicrobial agents using standard disc diffusion method. Based on the presence of intl1, 162 isolates harbored class 1 integrons, which were more prevalent in isolates from outpatients compared with those from healthy volunteers. The majority (85%) of the isolates were resistant to at least one antimicrobial agent with the following percent resistance: streptomycin 66%, tetracycline 60%, sulphamethoxazole 59%, ampicillin 52%, trimethoprim/sulphamethoxazole 47%, kanamycin 30%, nalidixic acid 27%, ciprofloxacin 23%, norfloxacin 22%, amoxicillin/ clavulanic acid 16%, gentamicin 8%, and amikacin 2%. The most frequent pattern of multiresistant strains (11%) was sulphamethoxazole- trimethoprim/sulphamethoxazole -ampicillin-tetracycline-streptomycin. Multiple drug resistance was more frequent in integron-positive isolates (89%) than those in integron-negative E. coli (57%). These data indicate that human fecal E. coli is a reservoir of antibiotic-resistant genes that poses a significant risk of the spread of microbial resistance in the community.
Phongpaichit
Souwalak
S
Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand. souwalak.p@psu.ac.th
Wuttananupan
Kornvika
K
Samasanti
Wiwit
W
D016022:Case-Control Studies; D004197:Disease Reservoirs / Q000382:microbiology / Q000706:statistics & numerical data*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D005243:Feces / Q000382:microbiology; D006801:Humans; D032023:Integrons / Q000235:genetics; D008826:Microbial Sensitivity Tests; D010045:Outpatients; D011159:Population Surveillance; D015995:Prevalence; D013785:Thailand / Q000453:epidemiology