OBJECTIVE:
The present study was undertaken to assess 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 female. Collected samples are of four origins; pus, urine, blood and ear swabs and sensitivity testing is done by 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 antibiotics resistant strains. Therefore clinicians should avoid readministration of previously prescribe antibiotics

KEY WORDS:
Antibiotic susceptibility, P.aeruginosa, Ciprofloxacin, Nosocomial infections.