OBJECTIVE: The present study was undertaken to evaluate the effect of previous antibiotic exposures and antimicrobial susceptibility patterns of pseudomonas.METHODOLOGY:To isolate pseudomonas species samples are collected from hospital patients and laboratories of Karachi, Pakistan of both males and females. Collected samples are of four origins; pus, urine, blood and ear swabs and their sensitivity testing is done by Agar Disc-diffusion method.RESULT: P.aeruginosa is most commonly isolated from hospital samples and it is leading cause of nosocomial infections. The highest number of Pseudomonas species are isolated from pus sample then in urine, blood and ear swabs while higher no.
of urine sample are found to be positive in females then in males. However Ciprofloxacin found highly effected for clinical isolates then hospitals associate samples.CONCLUSION:Due to significant use of antibiotics causes changes in microbial genes and leads to formation of multiple drug resistance (MDR) strains. Therefore clinicians should avoid re-administration of previously prescribe antibiotics.KEY WORDS:Antibiotic susceptibility, Disc-diffusion method, P.aeruginosa, Ciprofloxacin, Nosocomial infections.