RESUMEN
To assess antibiotic resistance of Pseudomonas aeruginosa isolates from four types of clinical specimen at Al-Shifa hospital, and to compare susceptibilities of those isolates according to their source. Clinical specimens from Al-Shifa hospital in Gaza were analyzed between January and December 2002. Pseudomonas aeruginosa were isolated and identified by conventional methods. The antibiotic resistance rates were measured by modified Kirby-Bauer disk diffusion method. Data were analyzed statistically using SPSS [version 11]. The number of isolated P. aeruginosa was 541, obtained from 4 types of clinical specimens. Pus was the major source of P. aeruginosa isolates [64%], followed by urine [24%], sputum [7.0%] and Blood [5.0%]. However, considering the number of specimens cultured, sputum showed the highest Pseudomonas isolation rate [49%], followed by Pus [23%], urine [8.0%] and Blood [6.0%]. The highest percentage rates of resistance were found against amoxicillin [99% of all isolates], cephalexin [98.5%], cefaclor [97.4%], doxycycline [96.2%], trimethoprim/ sulfamethoxazole [94.7%] and nalidixic acid [93.5%]. Ciprofloxacin was the most effective of all the tested antimicrobials, followed by Gentamicin and Amikacin. Significant statistical [P >/= 0.05] difference in isolated strain susceptibility was detected among some of the antimicrobials depending on the specimen source. This study showed that antimicrobial resistance of Pseudomonas aeruginosa was high and alarming. Significant difference in the resistance pattern of isolates from different specimen type can be useful in clearing the picture of resistance problem and suggests that due care must be taken in hospital settings to adequately diagnose pseudomonal infections and prescribe the antibiotic treatment most effective in preventing the increase in multidrug resistant organisms