Multidrug resistant profiles of clinical isolates of Escherichia coli, Salmonella typhi and Shigella species

Abstract

In order to determine the antibiotic susceptibility pattern and multi antibiotic resistance index of E.coli, Salmonella typhi and Shigella species, a total of 32 pre-identified clinical isolates were obtained and subjected to conventional biochemical and gram staining reaction for confirmation. Antibiotic susceptibility testing to ten commonly prescribed antibiotics (Amplicin (PN:30 mcg), Gentamicin (GEN:10 mcg), Streptomycin (STR:30 mcg), Septrin (SXT:30 mcg), Nalidixic acid (NAL:30 mcg), Ciprofloxacin (CIP:10 mcg), Augmentin (AU:30 mcg), Reflacin (PEF:10 mcg), Tarivid (OFX:10mcg), and Ceporexin (CEP:10 mcg) was considered using disc agar diffusion method and reported with the Clinical and Laboratory Standard Institute Interpretative chart. Zones of inhibition were measured and Multiple Antibiotic Resistance index was calculated. Salmonella isolates demonstrated a high rate of susceptibility to Tarivid (90%), Reflaxin (90%), Gentamycin (80%), ciprofloxacin (60%), Augmentin (80%) and moderately susceptible to Streptomycin (40%) and Septrin (20%) with high resistance to Nalidixic acid (90%), Amplicin (90%) and Ceporexin (70%). Nearly all Shigella isolates were susceptible to Augmentin (80%), Reflaxin (90%), Tarivid (80%), intermediate susceptibility was also noted in Streptomycin (40%) and Ceporexin (50%) while high resistance to ciprofloxacin (80%), Amplicin (90%), Septrin (70%) and Nalidixi acid (90%). High rate of resistance was observed to nearly five antibiotics in E,coli with low susceptibility rate to all the antibiotics tested. All the isolates had Multiple Antibiotic Resistance index greater than 0.2 and above. This may be as a result of previous exposure to antibiotics and development of resistance to commonly prescribed antibiotics, hence, antimicrobial susceptibility testing is imperative in selecting therapeutic options.