African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5136

Full Length Research Paper

Microbial susceptibility of bacteria isolated from open fracture wounds presenting to the err of black-lion hospital, Addis Ababa University, Ethiopia

Yishak Abraham and Biruk L. Wamisho
1Department of Microbiology, Immunology and Parasitology, Addis Ababa University, Faculty of Medicine (AAU-MF), Ethiopia. 2Orthopedic Surgery, AAU-MF, Orthopedic Department, Ethiopia.
Email: [email protected]

  •  Accepted: 28 September 2009
  •  Published: 31 December 2009

Abstract

Sixty to seventy percent of compound fractures are believed to be contaminated with bacteria at the time of injury from both skin and environment. Infection of open fractures depends on the environmental, microbial and host factors. In developing countries like Ethiopia, a high incidence of open fracture wound infection is suspected though the magnitude of the problem is not known. No documented report on bacterial isolates from open fracture wounds and their drug resistance pattern. In set-ups where immediate culture and sensitivity tests are difficult, sound epidemiological knowledge of microbes helps in rationally selecting antibiotics for prophylaxis and empiric treatment as well. To profile the antimicrobial susceptibility pattern (Culture and sensitivity) of the bacterial isolates from open fracture wounds to the commonly used antibiotics. Addis Ababa University, Black-Lion (‘Tikur Anbessa’) Hospital-BLH, is the country’s highest tertiary level referral and teaching Hospital. The Hospital has a newly established separate ER to receive trauma patients. 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, - a tertiary University Hospital, Addis Ababa, Ethiopia. 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. A total of 162 bacterial pathogens were isolated from the 200 open fracture wounds sampled. Staphylococcus aureus was the dominant isolate (14.8%) followed by Acinetobacter spp. (11.4%). Of the culture-positive wounds, 51.2% showed mono-microbial growth (single bacterial type) and 48.8% showed polymicrobial (more than one bacterial type) growth. The gram-positive and -negative bacteria accounted for 34.0 and 66.0%, respectively (p < 0.05). All gram-positive bacterial isolates showed low level of resistance (<60%) to all antibiotics tested except for ampicillin and penicillin to which they showed intermediate level of resistance (60 - 80%). Most gram-positive isolates, 29/55 (52.7%) showed multiple drug resistance (resistance to three or more drugs). 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 resistants (MDR). Staphylococcus aureus was the commonest isolate associated with open fracture wound contamination. Gentamicin, ciprofloxacin and norfloxacin were the most effective drugs against the tested gram- positive and -negative bacteria and should be considered in empirical antibiotic selection. 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.

 

Key words: Compound fracture, open fracture wounds, bacterial isolates, antimicrobial susceptibility testing.