Biofilm Production by Multi Drug Resistant Bacterial Pathogens IsolatedFrom Patients in Intensive Care Units in Egyptian Hospitals

Abstract

Antibiotic resistance among Multi drug resistant (MDR) Gram negative bacteria causing hospital acquired infections poses a great threat in ICU patients. The treatment of such infections has become increasingly problematic, due to their intrinsic and/or acquired resistance to variable classes of antibiotics. Moreover, the demonstrated ability of these bacteria to grow as biofilm is believed to have a major role in their ability to resist various antibiotics. The aim of this study is to evaluate the role of the selected genes in biofilm formation in 3 significant MDR bacterial isolates (Acinetobacter baumannii and Pseudomonas aeruginosa and Stenotrophomonas maltophilia). In this study a total of 625 non replicated Gram negative non-fermenter bacterial isolates were isolated from different clinical specimens from intensive care units from hospitals in Egypt. These bacterial isolates were identified biochemically, API20E and genetically. The antibiogram of all isolates was determined and revealed that all isolates were MDR and colistin was the most potent antibiotic against all A. baumannii and P. aeruginosa isolates. While trimethoprim/sulfamethoxazole combination was the most potent against all S. maltophilia isolates. Detection of biofilm formation of isolates was done by Tube method. While, Quantification of biofilm formation was done by the microtiter plate method using crystal violet (CV) assay. Screening for some selected genes responsible for biofilm formation was done by PCR as bap gene which is responsible for biofilm formation in A. baumannii, rhlI gene in P. aeruginosa strains and rmlA, spgM, rpfF genes in S. maltophilia. The results revealed the presence of these genes in both strong and weak biofilm producer isolates. These final results showed the significance of these genes in biofilm formation.