Evaluation of the Potency of Commercial and Locally Prepared Antibiotic Discs on Clinical Bacterial Isolates in Calabar, Nigeria

Ofonime M. Ogba, Nsikak I. Udo, Paul C. Inyang-Etoh, Oluwayemisi A. Olorode


Antibiotic susceptibility discs are used for vitro susceptibility testing of antimicrobial agents to fast growing bacteria and fastidious species by agar diffusion method. It is a semi quantitative method. This study was designed to assess the efficacy of commercial antibiotic discs over in-house prepared discs. Identified clinical isolates were obtained in house in the Department of Medical Microbiology/Parasitology, University of Calabar Teaching Hospital, Nigeria. Staphylococcus aureus (ATCC 7553) and Escherichia Coli (ATCC 25922) were obtained and used as controls. The antibiotics tested includes; Ciprofloxacin, Erythromycin, Amoxicillin, Gentamicin, Zinacef.These were obtained commercially from Pharmacy shops. The local antibiotic dics were prepared with Whatman filter paper number 3. The antibiotic susceptibility testing was done using Kirby-Bauer method. Out of the 40 clinical isolates tested, 15(37.5%) were Staphylococcus aureus while 10(12.5%) each were Escherichia coli and Pseudomonas aeruginosa respectively. Only 5 isolates of Proteus vulgaris were used. The susceptibility profile of isolates to the commonly used local antibiotic discs ranged between 66.7% to 100%, while the range for commercial discs was 53.3% to 86.7%. Locally prepared discs were found to be more effective than commercial discs. The high resistance rates (0.0% to 33.3%) of clinical isolates to the commercial discs may be attributed to prolong exposure to environmental factors such as heat, moisture, sunlight as well as humidity when transported to retailers and the final users. There is need for constant monitoring and quality controls of susceptibility testing in our laboratories for the production of quality results and efficient patient care. Antibiotic susceptibility discs can be prepared locally for routine laboratory use; this may indirectly reduce importation of commercial discs and the burden on foreign exchange.

Keywords: Antibiotic susceptibility testing, discs, potency.

Full Text:



Daniel, P. N., Kitshbaum, A., Kramer J. (2014): The assay and control of antibiotic discs, Antiobiotic chemo-therapy: 10:249-258

Silva, E., Díaz, JA., Arias, MJ., Hernández, AP., Torre, A. (2010). BMC Clinical Pharmacology 2010, 10:3 http://www.biomedcentral.com/1472-6904/10/3

Center for Disease Control (2011) measurements and significance of antibiotic activity in the urine. P.. 41-49

Vineetha N, Vignesh RA, Sridhar D. (2015). Preparation, Standardization of Antibiotic Discs and Study of Resistance Pattern for First-Line Antibiotics in Isolates from Clinical Samples. International Journal of Applied Science; 1(11): 624-631

Ekundayo EO, Omodamiro OD. (2008). Evaluation of locally manufactured antimicrobial susceptibility testing discs in South Eastern Nigeria. African Journal of Clinical and Experimental Microbiology. 2008;99(3):122-128.

Sudha V, Prasad A, Khare S, Bhatia R. (2001). Antimicrobial susceptibility testing in India – A status survey. Indian Journal of Medical Microbiology;19:222-223.

Greenberg L, Fitzpatrick KM, Branch A.(1957). The Status of the antibiotic disc in Canada. Canadian Medical Academic Journal. 1957;76:194-198.

Eze PM, Ajaegbu EE, Esimone CO. (2014). Evaluation of the paper quality of antibacterial discs commercially available in Nigeria. Journal of Scientific Research and Reports; 3(8):1079-1087.

John FA & Rippers RA. (2012). Preparation and control of antiobiotic susceptibility discs and other devices containing antiobiotic. Pp. 41-48

Clinical and Laboratory Standards Institute (CLSI) (2010a). Approved standard M2-A10. Performance standards for antimicrobial susceptibility tests, 10th ed. CLSI, Wayne, Pa.

Ogba OM, Mandor BI & Omang HM. (2014). Antibiotic susceptibility pattern of Serratia marcescens isolates from wound infections in a tertiary health institution in Calabar, Nigeria. El Mednifico Journal, (S.l.) 2(3): 223-226. July 2014. http://www.mednifico.com/index.php/elmedj/article/view/201/136

Clinical and Laboratory Standards Institute (CLSI) (2010b). CLSI document M100-S19. Performance standards for antimicrobial susceptibility testing, 20th informational supplement, Wayne, Pa.

Ayiegoro, JI, Daniel UV & Thomas VO. (2008). Efficacy of different antibiotics on gram negative organisms. Pp. 41-48.

Waksman, P. E., Shrivatsava, S. Chaudhary, M. (2009) ceftraixone sulbactam combination: Microbial analysis by variation of ratios and comparative disc diffusion. Current Resistant in Bacteriology 2: 505.

Epoke, J., Igumbor, E. O., Asuquo, A. E. & Tichawowona, C. (2003). Locally prepared antibiotic sensitivity discs: a substitute for imported commercial discs. Global Journal of Pure and Applied Sciences 9 (4): 453-456.


  • There are currently no refbacks.

International Journal of Biomedicine & Life Sciences (IJBLS) is licensed under a Creative Commons Attribution 4.0 International License Based on a work at http://www.ijbls.ielas.org

Copyright © 2016-2022 International Journal of Biomedicine & Life Sciences (IJBLS)

ISSN (online) 2545-4129

Disclaimer: Articles on International Journal of Biomedicine & Life Sciences (IJBLS) have been previewed and authenticated by the Authors before sending for the publication. The Journal, Chief Editor and the editorial board are not entitled or liable to either justify or responsible for inaccurate and misleading data if any. It is the sole responsibility of the Author concerned.