الملخص

Objectives: 1- To evaluate the incidence of Pseudomonas aeruginosa bacterial pathogens in burn patients. 2- To determine the antibiogram profile of Pseudomonas aeruginosa to selected antibacterial agents. 3- To assist their production of β-lactamases. Patients and methods: This study enrolled 90 burned patients including 63 (70%) females and 27 (30%) males. Pus and wound swabs were collected aseptically from these patients and assessed microbiologically. The isolates of P. aeruginosa were tested for their susceptibility to 10 selected antimicrobial agents, and evaluated for β-lactamases using iodometric and double disk approximation methods. Results: Out of the 90 studied patients with second and third degree burns, 60 (66.7%) yielded positive bacterial growth, while 30 (33.3%) were culture negative. From the total 105 bacterial isolates 88 (83.8%) were gram negative and the remaining 17 (16.2%) were gram positive. The predominant microorganism was P. aeruginosa (50%), whereas the least isolated one was Proteus (3.3%).The antibiogram study of P. aeruginosa showed that the least resistance was against piperacillin, while the highest resistance was noted in cases of carbencillin and cefoxitin. Multidrug resistance (MDR) P. aeruginosa formed 44.4% of the total isolates of P. aeruginosa and they had statistical association with ceftriaxone, meropenem, ceftazidime and amikacin consumption. Ninety percent of P. aeruginosa were β-lactamases producer and 10 % of them produced the inducible β-lactamases. Conclusion: The bacteria isolated from Burn Units are the best examples for the study of pathogenic bacterial species, specially Pseudomonas aeruginosa, other enteric bacilli and Staph. aureus which frequently responsible for human colonization. Also, Pseudomonas aeruginosa and other gram negative bacilli are frequently associated with nosocomial burn infection. Furthermore, most isolates of P. aeruginosa from Burn Units are β- lactamases producers and most of these isolates were MDR pseudomonas aeruginosa.