Abstract

This study investigated the isolation rate and antimicrobial susceptibility of Escherichia coliand other coliforms from asymptomatic male and female students of Niger Delta University in Bayelsa State, Nigeria. E. coli and other coliforms from midstream clean-catch urine samples of asymptomatic male and female students were isolated and tested for their susceptibility to commonly used antimicrobial agents using the disk diffusion protocol described by the Clinical Laboratory Standards Institute (CLSI). Of the few subjects that harbored E. coli, more were males. Zone sizes for both isolate groups from males were higher than those from females. E. coli were more susceptible to the antimicrobials than the non - E. coli (unclassified coliform) isolates for both subjects, although the overall susceptibility of both isolate groups was poor. Gentamicin was the most active (64.5% for E. coli and 33.3% for unclassified coliforms) while tetracycline was the least (22.7% for E. coli and 0% for unclassified coliforms). The most common resistance phenotypes were “ATCtGSNa” (for E. coli) and “ATCtGSNaNC” (for unclassified coliforms); “ATCtGSNaNC” was observed in both isolate groups. Multiple antibiotic resistances were observed significantly in both E. coli (83.9%) and the unclassified coliforms (100%). As against 9.7% of the E. coli isolates, 40% of the unclassified coliforms were resistant to all the antimicrobials. MAR indices were very high (all above 0.2) in both isolate groups. Although asymptomatic male students of Niger Delta University harbored more E. coli than the female students, isolates from the female students pose greater risk of antimicrobial resistance owing to their lower susceptibility to antimicrobials compared with those from their male counterparts. The prior exposure of all the isolates to antibiotics as suggested by their high MAR indices provides justification for continuous monitoring of bacterial susceptibility to antibiotics before prescription in order to ensure adequate treatment of infections arising from urinary pathogens and reduction in the spread of bacteria resistant strain.

Key words: Escherichia coli, urine, asymptomatic, antimicrobial susceptibility.