COMPARATIVE SUSCEPTIBILITIES OF 0 - LACTAMASE PRODUCING ISOLATES OF PROTEUS MIRABILIS TO CEFTRIAXONE ALONE AND IN COMBINATION WITH SULBACTAM

Objective: To evaluate the increase in Susceptibilities of Ceftriaxone resistant clinical isolates of Proteus mirabilis by combining sulbactam with ceftriaxone. Material and Methods: An institution based analytic observational study was carried out at Department of Microbiology, Khyber Medical College Peshawar. b - lactamase producing Proteus mirabilis were identified and cultured in Mueller Hinton medium in Petri dishes. The antibiotics disks containing ceftriaxone alone and in combination with sulbactam were placed in the same Petri dishes about 24 -30mm apart. The zones of inhibition were measured by following National Committee for Clinical Laboratory Standards zone diameter criteria in using disk diffusion method. Results: The disks containing the combination of ceftriaxone and sulbactam showed larger zones of inhibition. The ceftriaxone alone had some anti bacterial activity against Proteus mirabilis. But by combining 20, 30 and 40 ^g ceftriaxone with sulbactam in 1:1 ratio, the sensitivity was increased by 32.5%, 55% and 62.5% respectively. In 2:1 ratio, the combination produced 47.5%, 60% and 67.5% increase in sensitivity. Conclusion: The sensitivities of Proteus mirabilis to Ceftriaxone can be restored by adding sulbactam.