In this study, an assessment of the efficacies, potencies and qualities of 11 brands of 5 different antibiotics including 3 brands of ampiclox and 2 brands each of ciprofolxacin, gentamicin, rifampicin and tetracylcine sold in Calabar, South-South region of Nigeria was carried out using the agar diffusion technique (sensitivity testing). The efficacies, potencies and qualities of these antibiotics were tested against some clinical isolates which include Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes in vitro. The overall mean zones of inhibition for the test organisms ranged from 33.0 -34.7 mm, with 33 mm for E. coli, 20.9 mm for K. pneumoniae, 34.7 mm for P. aeruginosa, 31.4 mm for S. aureus and 17.6 mm for S. pyogenes. The result showed that 3 (60%) of the antibiotics (alaclox, ciprofloxacin and rifampicin) tested showed lower potency against the test organisms compared with the standard controls. Alaclox produced significantly (P < 0.05) lower zones of inhibition compared to the other brands of ampiclox (superclox and vitaclox) on S. aureus and S. pyogenes. However, significant differences (P = 0.007, P = 0.026, P = 0.050, P = 0.012) were observed between the zones of inhibition of the test antibiotics and standard controls for the 3 brands of ampiclox tested on all the test organisms except for K. pneumoniae. There were also significant differences (P = 0.038, P = 0.038, P = 0.049, P = 0.025, P = 0.032) between the zones of inhibition observed for ciprofloxacin and their standard controls. Both brands of rifampicin (vitals and medifampi) produced significantly (P = 0.020, P = 0.038) lower zones of inhibition on E. coli and S. pyogenes compared to their standard controls. Our result also showed there were no significant differences (P > 0.05) between the observed zones of inhibition and standard controls of the brands of gentamicin (richem) and tetracycline. These overall and mean potencies of the test antibiotics showed differences in their efficacies, potencies and qualities. This confirmed that some brands of ampiclox, ciprofloxacin and rifampicin antibiotics sold in Nigeria do not contain the acclaimed quantity of active ingredients to exert bacteriocidal or bacteriostatic effect on common pathogens. © 2010 Academic Journals.
