Antibacterial Activity of three Broad Spectrum Antibiotics against some Clinical Bacterial Isolates

Antibiotics, either produced by microorganisms or formulated synthetically have a dynamic attribute of inhibiting Growth or completely suppressing the toxic effect of microorganisms. This study aimed to compare the antibacterial strength of three common antibiotics: Ciprofloxacin, Gentamycin and Erythromycin against Escherichia coli, Pseudomonas aeruginosaand Staphylococcus aureusisolated from clinical samples such as Nasal swab, wound swab, urine and high vaginal swab.The sensitivity test was carried out using the Disc diffusion method. A total of 25 isolates were obtained from these samples after culturing. Of the 25 isolates, 5(20%) yielded pseudomonas aeruginosa, 10(40%) yielded Staphylococcus aureusand Escherichia coli respectively. Gentamycin demonstrated the highest antibacterial activity against the test organisms with 100% activity against Pseudomonas aeruginosa and 90 and 70% activity against E. coli and S. aureus. It was followed by ciprofloxacin which had 60 and 70% activity against E. coli and S. aureusrespectively. Erythromycin was the antibiotic with the least activity, but it showed higher activity (80%) than ciprofloxacin (40%) against Pseudomonas aeruginosa. Therefore gentamycin is a better choice of antibacterial therapy against infections causedbyE. coli, P. aeruginosaand S. aureus.It exhibited the highest antibacterial effect on these organisms than the other antibiotics tested