Phenotypic and Genotypic Characterization of Pseudomonas Aeruginosa Isolates from Burn Patients

Abstract

Background: Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen that still develops life threatening infections in patients with immunological system defects like burns. It has been estimated that 75% of all deaths following burns are due to infections. Objectives: This study was designed to evaluate the prevalence and drug susceptibility profile of P. aeruginosa in patients admitted to a burns unit and to investigate the potential sources of infection in burn patients by genotyping using pulsed field gel electrophoresis (PFGE). Methodology: The study was performed in King Fahd Hospital (KFH), Almadinah Almunwarah during a ten month period. A total of 106 burn wound infection (BWI), 40 environmental and 10 health care workers (HCWs) samples were isolated then identified by conventional biochemical methods and API 20E system. Antibiotyping was performed by disc diffusion. Molecular relatedness of P. aeruginosa strains was investigated by pulsed field gel electrophoresis. Results: The most isolated organism was P. aeruginosa (31.6%), followed by Methicillin–Resistant Staphylococcus aureus (MRSA) (21%) and Acinetobacter baumannii (A.baumanii) (17.5). Colistin (100%) was the most effective drug against P. aeruginosa while the least effective drug was ticarcillin (48.1%). Typing of 27 isolates by PFGE revealed four pulso-types A, B, C and D and pulsotype B revealed 3 subtypes, subtypes B 1 , B 2 and B 3 . The isolates showed that 77.7% of isolates (from patients and environmental specimens) were genetically related. Also, Six patients had the same pulsotypes which were not detected in the environment. Conclusion: P.aeruginosa became one of the major concern in our hospital and implementation of infection control strategies is a major concern to avoid the spread of this threat. Environmental sources may have a significant role in spread of P. aeruginosa among hospitalized patients.