ABSTRACT

Susceptibility of organisms to antibiotics needs to be monitored because of rising antibiotic resistance. For this purpose, disc diffusion technique was employed in this study. In this study, low cost antibiotic discs (BMDR antibiotic discs) were prepared by impregnation of antibiotic solution onto What man filter paper grade TSfo.1. After the preparation of the disc, they were standardized by comparing their efficacy with the commercially available Abtek discs. Both Categories of discs were tested repeatedly against typed strains of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923 as well clinical isolates of same organisms in the vitro antimicrobial susceptibility testing. The zones of inhibition in the range of 9mm - 27mm produced by the respective antibiotics on the BMDR discs compared favorably with that of the standard discs presenting zone sizes within the range of 13mm to 23mm for the clinical isolates, it was also observed from this study that in one of the isolates which exhibited complete resistance to all the antibiotics on the Abtek disc, a similar trend was visible on the BMDR antibiotic discs. Both test organisms (Escherichia coli and Staphylococcus aureus) showed 100% resistance to ampicillin on both disc types. In as much, this study demonstrate that, local and foreign discs appear to be producing distinct zones of inhibition, further studies are needed on periodic basis to substantiate the result observed in this study, which was on a small scale.