Abstract

 

Infection of open fractures depends on the microbial environment, fracture handling and host factors. Sound knowledge of the bacteriological epidemiology and antimicrobial susceptibility helps to rationally select prophylactic antibiotics. To isolate and identify the bacterial agents present on compound (open) fracture wound and to determine the antimicrobial susceptibility pattern. Addis Ababa University, 'Tikur Anbessa' Specialized Hospital. During a period of November 2007 and May 2008, a cross-sectional prospective study was conducted to determine the bacteriology of open fracture wounds of 191 informed and consented patients (200 wounds) who visited the orthopedic department of 'Tikur Anbessa' Hospital. Wounds were graded using Gustilo-Anderson's classification. The detailed bacteriological profile of the wounds swabs collected by Levine's technique is documented. All of the wound specimens were processed for microscopic examination, culture and sensitivity testing. Of the 191 patients, 82.7% were males and the average age of the patients was 31.55 years (age range 4 to 75 years).Most of the open fractures were caused by road traffic injuries (37.2%) and occurred in lower extremity bones (60.0%). Twenty-three percent of the open fractures were Gustilo-Anderson grade I; 41.5% were grade II; 14.0% were grade IIIA; 5.5% were grade IIIB and 16.0% were grade IIIC. A total of 162 bacterial pathogens were isolated from the open fracture wounds sampled. Staphylococcus aureus was the dominant isolate (14.8%) and followed by Acinetobacter spp. (11.4%). The gram-positive and gram-negative bacteria accounted for 34.0% and 66.0%, respectively. 82 (41%) of the wounds were culture-positive of which 51.2% showed mono-microbial growth and 48.8% showed polymicrobial growth. All Clostridium spp. were susceptible to tetracycline, doxycycline, and kanamycin and showed low level of resistance (<60%) against chloramphenicol, clindamycin and penicillin. All gram-negative bacterial isolates showed low level of resistance (<60%) to all antibiotics tested except for ampicillin and amoxicillin (60-80%, intermediate level resistance). Fifty-one percent of the gram-negative bacterial isolates were identified as multiple drug resistant. Staphylococcus aureus was the commonest isolate followed by Acinetobacter species, E. coli and Pseudomonas species. Gentamicin, ciprofloxacin and norfloxacin were the most effective drugs against the tested gram positive and gram-negative bacteria. The findings underscore the need for routine microbiological investigation of open fracture wounds and monitoring antimicrobial resistance pattern for the use of prophylactic and therapeutic antibiotics. Keywords: Compound fracture, Open fracture wounds, Bacterial isolates, Antimicrobial susceptibility testing.