Resistant Pseudomonas Aeruginosa is an emerging threat to patients in the Intensive Care Unit

Background: Pseudomonas aeruginosa infections in the ICU are a constant problem and its prevention is extremely important. P. aeruginosa colonization has been reported to originate from exogenous sources such as tap water, fomites and/or patient-to-patient transmission, or as an endogenous etiology related to antibiotic use. The aim of this study is rapid diagnosis of Pseudomonas aeruginosa and proper identification of the source of transmission using new molecular techniques with determining the presence of MBL (metallo-B-lactamase) producing Ps. aeruginosa and avoiding the existence of resistant strains in the ICU. Material and Methods: samples are taken from adult patients (50), health staff (18) and environment (100). After isolation and identification of pseudomonas, Antimicrobial susceptibility testing was performed for ten different therapeutically relevant antibiotics by the VITEK2 automated machine. Screening for metallo-B-lactamase (MBL) production was done. All the pseudomonas aeruginosa isolates were typed by RAPD-PCR (Randomly amplified polymorphic DNA PCR) typing method. The 124 to 127-bp enterobacterial repetitive intergenic consensus (ERIC) primers were performed. All fragments generated were analyzed for determining the RAPD-types and ERIC-types. Results: 32% of patient samples were positive for Pseudomonas and only 11% (n=2) of staff hand samples were positive. The highest frequency of Pseudomonas isolation from environmental samples was from suction apparatus bags (86%), water tap/sink (78%). The (MBL) producing Pseudomonas is much more resistant to all antibiotics tested except Colistin to which nearly all Pseudomonas strains are sensitive. ERIC typing method gave higher discriminatory index (0.7955) than RAPD (0.7706) and that the combination of both (0.7977) was superior to either alone. Antibiogram gave the lowest discriminatory index (0.7232). Conclusion: Hand hygiene, environmental cleaning and disinfection of patient objects could reduce environmental reservoirs of Ps. aeruginosa. It is better to limit the usage of antibiotics in the ICU as carbapenems to be used only when absolutely needed. RAPD and ERIC molecular typing methods were superior to antibiotic typing and should be used in tracing the source of infection.