ABSTRACT
Background: Pseudomonas aeruginosa is a common pathogen that causes nosocomial infections in intensive care units. Strain typing is an extremely useful tool in tracking the source of infection. The present study aimed to elucidate the epidemiology of P. aeruginosa isolates in intensive care units [ICUs] in both Egypt and Saudi Arabia
Palients, Materials and Methods: two hundreds and seventy clinical and environmental samples were collected from adult lCUs of both Zagazig University Hospital, Egypt and King Abdulaziz University Hospital, Saudi Arabia. Isolates have been typed using both antibiogram and enterobacterial repetitive intergenic consensus-polymerasr chain reaction [ERIC-PCR]. Also, testing for metallo-beta-lactamase [MBL] production was done
Results: The study showed that in Egypt and Saudi Arabia, the isolation rates of P. aeruginosa from patients, staff hands and environmental samples were [32.8%, 10.0 %and 25.0 %] and [30.0%, 6.7 %and 23.3%]; respectively. In Egypt, the highest rate was from burn exudates [66.7%] while in Saudi Arabia, it was from endotracheal aspirate [33.3%]. As regards the isolation rate from the environmental samples, in Egypt was 25.0% where it was highest [57.1%] from suction apparatus tubing. In Saudi Arabia, it was 23.3% and was highest [42.9%] from both suction apparatus tubing and artificial ventilation [AV] machine tubes. In Egypt and Saudi Arabia, the highest rate of antibiotic resistance of clinical isolates was to aztreonam [96.6% and 98.1%] followed by cefepime [76.3%] and tobramycin [67.8%] in Egypt whereas in Saudi Arabia it was to meropenem [72.2%] and ceftazidime [70.4%]. On the other hand, the highest rate of antibiotic resistance of enviromental isolates was 100% to aztreonam and ceftazidime in Egypt and ceftazidime and cefepime in Saudi Arabia. Notably, colistin was the only antibiotic to which nearly all strains were sensitive. As regards screening for MBLs production in IMP-resistant strains, in Egypt and Saudi Arabia, it was 16/29 [55.2%] and 36/54 [66.7%]; respectively in clinical isolates, 2/3 [66.7%] in environmental strains and was not detected in staff hand strains with statistically significant difference [P < 0.001]. In both Egypt and Saudi Arabia. ERIC typing method gave higher discriminatory index [0.801] and [0.785] than antibiogram that gave the lower discriminatory index [0.7123] and [0.728]; respectively. In Egypt, suction apparatus tubing, artificial ventilation [AV] machine tubes and drainage basin while in Saudi Arabia the former two sources have a central role in the spread of organism in the ICUs. In addition, the patients MBL-producing strains were epidemiologically linked to suction apparatus tubing and AV machine tubes in both Egypt and Saudi Arabia
Conclusions: ERIC molecular typing was superior to antibiogram typing and should be used in tracing source of injection when available