Antimicirobial Susceptibility Patterns of Escherichia coli and Shigella sp Isolated from Diarrhoea Stool of Children

Abstract

A total of 56 and 24 strains of E. coli and Shigella sp. isolated from children less than five years with diarrhoea attending 3 different hospitals in South South Nigeria were screened for their antibiotic resistance patterns. Approximately 80% of E. coli and 70% of Shigella isolates were resistant to tetracycline. The most resistant pattern encountered was with amoxicillin, tetracycline and amoxicillin-clavulanic acid. About 92.9% of E. coli isolates and 87.5% of Shigella isolates were multidrug resistant (MDR). Plasmid curing and conjugation experiment were carried out on 31 selected E. coli donor isolates which were resistant to tetracycline and sensitive to nalidixic acid. Acridine orange was used as the curing agent. Curing of the selected donor isolates showed that tetracycline resistance in 87% of the isolates were plasmid mediated. Transfer rates of 77.4% (24/31) and 29.0% (9/31) were obtained for intra and inter-species tetracycline resistance respectively. The study revealed that tetracycline resistance and transfer among the isolates was quite high yet tetracycline is not commonly used to treat diarrhoea in ages 0-5 yrs. Therefore mechanisms other than selective pressure might exist for maintaining a resistant bacterial pool.