Prevalence of Enteropathogenic Escherichia coli (EPEC) in Adult Diarrhea Cases and their Antibiotic Susceptibility Pattern

Introduction: Diarrheagenic Escherichia coli (DEC), an important etiologic agent of diarrhea is a major public health problem in developing countries. Relatively few studies have reported the role of enteropathogenic E. coli (EPEC) as etiological agent of adult diarrhea.
Objective: To know the prevalence of EPEC in adults and to know their antimicrobial susceptibility patterns.
Methods: Diarrheagenic stool samples (n=300), received at the department of Microbiology, Kasturba Medical College hospital, Mangalore, were cultured to isolate E. coli and other intestinal pathogens. Biochemically identified E. coli isolates were further characterized by polymerase chain reaction (PCR). Moreover, all the stool samples were subjected directly to PCR. Antibiotic susceptibility for EPEC was done by Kirby Bauer’s disk diffusion method.
Results: Of the 300 stool samples processed, 61 samples showed the growth of E. coli. Four samples had grown Shigella flexneri, three were Vibrio cholerae and One was Aeromonas hydrophila. Among the E. coli isolates characterized by PCR, four were typical EPEC, and atypical EPEC and one isolate was found to be Enterotoxigenic E. coli (ETEC). PCR performed directly on stool samples also yielded the same result. Antibiotic susceptibility testing revealed 42% of the E. coli other than DEC to be extended spectrum beta lactamase (ESBL) producers. However, one of the atypical EPEC was an ESBL producer.
Conclusions: In this study DEC, including EPEC types I and II, was found in a number of adult diarrheagenic stool samples and could be a possible cause of diarrhea in these patients. our study highlights the importance of PCR to differentiate atypical and typical EPEC. Presence of ESBL in commensal E. coli is a concern. Further characterization of these isolates from diarrheagenic individual and healthy controls is necessary to know their epidemiological significance.