Comparative Study on Effectiveness of Commercial Antibiotic Discs in Federal Capital Territory (FCT), Nigeria

Clinically, antimicrobial susceptibility testing results provide guidance in the choice of antimicrobial agents in patient care. The accuracy of results from antimicrobial susceptibility testing can be affected by multiple factors including the media, antimicrobial discs or preparations, inoculum’s size, plate reading and incubation conditions. Misleading results from antimicrobial susceptibility test leads to the indiscriminate and irrational use of antibiotics and have impacted grossly to the global challenge of antimicrobial resistance. The objectives of this study were to compare the efficacy of different brands of locally and foreign manufactured multi-antibiotic discs on bacteria and assess any significant variation. Two brands each of locally and foreign manufactured multi-antibiotic discs were purchased from retail stores within the FCT. The antibacterial susceptibility of Staphylococcus aureus ATCC 25923, Salmonella typhi ATCC 9150, Klebsiella pneumonia, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli ATCC 25922 and Streptococcus pyogenes were carried out using agar diffusion method. There were differences between the diameter zones of inhibition produced by the local brands and the foreign brands of antibiotic discs. Amoxicillin/clavulanic acid (30 µg) disc produced the highest variation within the four brands with zones of inhibition range 12.0 – 20.0 mm against the test organisms. There is need for regulatory bodies like NAFDAC and SON to routinely validate and assess the qualities of these products in the market.