Antimicrobial susceptibility of bacterial isolates from burn units in Gaza

Bacterial infections continue to be a leading cause of morbidity and mortality among burn patients despite intensive prophylaxis and treatment. Often treatment is complicated by the emergence of antimicrobial resistance pathogens. There are no reports or published data on the susceptibility profiles of bacteria isolated from burn patients in the Gaza strip.

A cross sectional study was performed in the two burn units of Al-Shifa and Naser hospitals for 6 months from October 2010 to March 2011. A total of 118 wound samples from burn patients, 97 environmental samples and 28 samples from health care workers (HCWs) were collected and cultured according to the standard microbiological procedures. The bacterial isolates were identified by conventional methods and the antibiotic susceptibility profiles were determined by the standard disc diffusion method according to CLSI guidelines.

The overall percentage of positive cultures from both hospitals was 45.8%, where Nasser burn unit revealed higher positive cultures than Al-Shifa burn unit. Pseudomonas aeruginosa was the most common pathogen isolated (50%) followed by Enterobacter cloacae (28.3%). Meanwhile, fingers and nasal samples that collected from HCWs showed 78.6% and 32.3% positive cultures respectively, where P. aeruginosa was the highest pathogen isolated (32.3%), followed by Coagulase Negative Staphylococci (CoNS) (29%). Environmental samples also showed higher isolation rate of Pseudomonas and CoNS. Pseudomonas isolates from patients samples were found to be resistant to most of antimicrobials used except for piperacillin-tazobactam. The family Enterobacteriaceae isolated from patients and environmental samples were resistant to most of the tested antimicrobials. However, the Enterobacteriaceae isolates from HCWs samples were sensitive to the most of the tested antimicrobials. The incidence of methicillin-resistant Staphylococci according to oxacillin sensitivity test was 60% in patient's samples, 77.8% in HCWs samples and 90% in environmental samples.

High percentage of resistance was found among clinical isolates in general to the commonly used antibiotics with a notable increase in MRSA incidence among both patients and environmental samples as well as HCWs.