Prevalence and Drug-Resistance Patterns of Enterotoxigenic <i>Escherichia coli</i> and <i>Shigella</i> Species among Children with Diarrhea in Merida City, Mexico

Abstract

Enterotoxigenic Escherichia coli (ETEC) and Shigella are two of the leading causes of diarrhea among children in developing countries. The prevalence of ETEC and Shigella species resistant to antimicrobial agents is increasing. The aim of this study was to determine prevalence and antimicrobial resistance patterns of ETEC and Shigella species among under-five children with diarrhea in an urban region of southeastern Mexico. A cross-sectional study was conducted among under-five children with acute diarrhea from January 2013 to January 2014 at Merida city. Isolation, identification and antimicrobial susceptibility test of ETEC and Shigella species were performed using standard bacteriological protocols. Of 200 stool samples collected, 18 (9.0%) ETEC and 12 (6.0%) Shigella strains were isolated. Among 12 Shigella species Shigellaflexneri founded as 8 (66.7%), followed by Shigellaboydii 4 (33.3%). One hundred percent of ETEC and Shigella isolates showed resistance to ampicillin, carbenicillin and cephalothin. Also, high frequency of resistance for both ETEC and Shigella isolates was observed to nitrofurantoin (100%, 83.3%), respectively. However, when we analyzed the resistance patterns of Shigella by species, S. boydii showed more resistance (8 of 12 antimicrobials tested) in comparison to S. flexneri isolates. Multidrug resistance (MDR) (≥3 drugs) was observed among all ETEC and Shigella isolates, being the aminoglycosides the more effective drugs against these pathogens. In conclusion, these findings indicate that ETEC and Shigella spp. are important etiological agents of diarrhea among under-five children and a high rate of drug resistance, including MDR, to the commonly used drugs was observed in our region.