Journal of Al-Nahrain University Vol.10(2), December, 2007, pp.94-97 Science 94 ISOLATION AND IDENTIFICATION OF AEROBIC PATHOGENIC BACTERIA FROM BURN WOUND INFECTIONS Sinai W. Mohammed Biological Research, Unit Collage of Science, Baghdad University. Abstract This study was carried out at Al-Yarmouk teaching hospital in Baghdad, during the period 1/10/2003 to 30/3/2004. A total of 306 specimens were obtained from patients bedding in surgical wards suffering from burn wound infections, the most common single isolated pathogen was Pseudomonas spp (36.7%) as well as Klebsiella spp. (36.7%), and as mixed isolates (64.7%). Pseudomonas spp. & Klebsiella spp. were highly resistant to Cefixime (100%) and sensitive to Norfloxain (67.7%, 56.3%) and Ciprofloxacin (41.7%, 53.8%) in this study. Key words: burn wound–infection Introduction Burn wound infections are one of the most important and potentially serious complic- ations that occur in the acute period following injury (1, 2). These wounds are subsequently colonized with microorganisms, including gram-positive bacteria, gram-negative bacteria and yeasts, which derived from the host’s normal flora (gastrointestinal flora, upper respiratory flora) and from the hospital environment (3, 4, 5, and 6). Microorganisms may also be transferred to a patient’s skin surface via contact with contaminated external environmental surfaces, water, fomites, air, hydrotherapy treatment, and the soiled hands of health care workers (7, 8). The risk of invasive burn wound infection is influenced by the extent and depth of the burn injury, various host factors, and the quantity and virulence of the microbial flora colonizing the wound (8). The common burn wound pathogens are Pseudomonas aeruginosa, Klebsiella spp. and Staphylococcus aureus, which produce a number of virulence factors that are important in the pathogenesis of invasive infection (9, 10, and 11). The aim of this study was to determine the causative microorganisms of burn wound infection and antibiotic sensitivity. Method and material 1. About 306 specimens were collected from Al-Yarmouk Teaching Hospital in Baghdad, during the period from 1/10/2003–30/3/2004. The specimens were taken from patients undergoing surgical operation or burn in surgical wards. 2. All swabs obtained were cultured directly on blood agar and MacConkey agar for isolation of aerobic bacteria. Cultured plates were examined after overnight incubation at 37 o C, if no growth obtained on plates they were re-incubated for another 24 hrs. (12). 3. Identification of pathogenic bacteria was based on gram stained smear, biochemical test and culture media (13). 4. Antibiotics sensitivity was carried out by using Muller-Hinton medium, 5-10 colonies of each isolate were picked up with sterile loop and suspended into 2.5ml of sterile distilled water, suspension was taken by a sterile cotton swab then streaked the surface of all the plate in three different planes. By using the sterile forceps, the disks were placed on the inoculated plates and pressed firmly but gently into surface of the agar and then incubated at 37 o C for 18-24 hrs. After incubation the diameter of complete inhibition zones were measured using reflected light and ruler (14). 5. The statistic method used for analysis the result of this study was Chi-square test. Results & Discussion About 306 swabs were collected from burn-wound patients attending the surgical wards at Al- Yarmouk teaching hospital. The identification and differentiation of bacteria isolates from burn- wound swabs were done depending on Bergey's manual of