Isolation and Antibiogram of Shiga Toxin-Producing Escherichia coli O157:H7 from Diarrhoeic HIV/AIDS Patients in Lafia, Central Nigeria

Abstract

This study assessed the prevalence and antibiogram of Shiga Toxin-Producing Escherichia coli O157:H7 from Diarrhoeic HIV/AIDS Patients in Lafia, Central Nigeria. E. coli O157:H7 from stools of consenting HIV/AIDS patients were isolated by culture based, biochemical and serological assays. Confirmed isolates were tested for their susceptibility to commonly used antimicrobial agents using the disk diffusion method as described by the Clinical and Laboratory Standards Institute (CLSI). The prevalence of E. coli O157:H7 from Diarrhoeic HIV/AIDS patients was 1.9% of which 33.3% and 66.7% were from males and females respectively. The cumulative antibiotic resistance frequency of the isolates was 56.7%. All the 3(100%) E. coli O157:H7 isolates were resistant to Amoxicillin and Augmentin, 2(66.7%) to Cotrimoxazole, Sparfloxacin, Ofloxacin and Streptomycin. The isolates showed lower frequencies of resistance to Chloramphenicol (33.3%), Ciprofloxacin (33.3%), Gentamicin (33.3%), and Pefloxacin (0.0%). Resistance phenotypes recorded were: Cotrimoxazole-Chloramphenicol- Spafloxacin-Ciprofloxacin-Amoxicillin-Augmentin-Streptomycin; Spafloxacin-Amoxicillin-Augmentin- Gentamicin-Ofloxacin and Cotrimoxazole-Amoxicillin-Augmentin-Ofloxacin-Streptomycin with the same frequency (33.3%). There was joint resistance of E. coli O157:H7 isolates to almost all antibiotics tested, with the Multiple Antibiotic Resistance (MAR) index of 0.5 and 0.7 which indicates that these isolates were exposed to these antimicrobial agents. The high degree of antibiotic resistance and MAR indices suggests the need for continuous surveillance of antimicrobial resistance trends in immunocompromised patients who are highly susceptible to opportunistic infections with Shiga Toxin- Producing E. coli O157:H7.