RESUMEN
Burned patients are at increased risk for hospital-acquired infections. Pseudomonas aeruginosa is the most common bacterial pathogen involved in these infections. Epidemiologic typing is needed to discover the source of infection. Phenotypic characteristics of Pseudomonas aeruginosa could be used for this purpose. However, the genomic fingerprinting methods are now regarded as more accurate typing methods. Random amplified polymorphic DNA is thought to be an efficient genetic typing method. In the Burn Unit of Menoufyia University Hospital this study was carried out in order to overview the problem of hospital acquired infections in this unit, to identify the most common pathogen and to find out probable sources of infections. Fifty-three cases of nosocomial burn wound infections, ten medical personnels and thirty-one environmental samples were screened, bacterial isolates were identified. Epidemiologic study for the most common isolate [Pseudomonas aeruginosa] was done using antibiogram and pyocin production in addition to some genetic studies as plasmid profile and random amplification polymorphic DNA [RAPD] typing. Total number of Pseudomonas aeurginosa strains isolated from burn wound infections, medical staff and Burn Unit environment and equipments was 36. These P. aeurginosa strains were mostly sensitive to imipinem [69.5%] followed by amikin [61.2%]. Antibiogram typing classified these isolates into 9 groups. beta lactamase prduction was proved in 58% of strains. Pyocin typing revealed 5 types. Sixteen strains had plasmids with 7 different profiles. According to RAPD 24 different patterns were distinguished. Identical clones of Pseudomonas aeurginosa were identified: two clones were related to environmental sources [Hydrotherapy tub and stretcher of hydrotherapy]. Horizontal acquisition through health care worker [finger tips] was proved.Endogenous colonization was also found in two cases. The RAPD method is simple, fast and has high discriminatory power suitable for application in epidemiologic studies. Stringent infection control policies and education campaign are urgently needed