Co-infections a threat in the treatment of Staphylococcus aureus isolated from topical wounds of both HIV positive and HIV negative patients
AbstractBackground: Staphylococcus aureus (S. aureus) is documented as an opportunistic pathogen in HIV/AIDS infection. Increasing prevalence of resistance by S. aureus to commonly prescribed antimicrobials pose a threat in its treatment, resulting to increased morbidity and mortality. The importance of each pathogen in resistance of S. aureus to antimicrobials has not been established.
Objectives: To identify, characterised and determine bacteria associated with wound infection. To determine the relationship between HIV and infectors of wounds and the correlation of co-infection in S. aureus and drug susceptibility.
Design: A cross-sectional study conducted for over five years from 2003-2007. Setting: Centre for infections and parasitic disease Control Research, Kenya Medical Research Institute Clinic.
Subject: Outpatient who were 18 years and above presenting with topical wounds at CIPDCR- Busia; Kenya Medical Research Institute (KEMRI) clinic.
Results: A total of 175 isolates were obtained. One hundred and four (59.4%) were S. aureus, 28(16.0%) Proteus spp, 25(14.3%) E. coli and 18(10.3) Pseudomonas spp. 59(49.2%) wounds had one bacteria, 58(48.3%) had more than one and three (2.5%) had none. Out of the 70 HIV + patients, 38(54.3%) had one bacteria and 32(45.7%) had more than one bacteria. Out of the 50 HIV - patients, 21(42.0%) had one bacteria and 26(52.0%) had more than one bacteria. Resistances of S. aureus from co-infected (with more than one bacteria) wounds were higher than those S. aureus from singly infected wounds that is, MRSA in single infection and co-infections showed significance differences as follows: [P values = 0.045, odds =5.5 (1-29.2) for S. aureus versus S. aureus and E.
coli], [P values = 0.032, odds =9.0 (1.0-8.0); S. aureus versus S. aureus and Proteus], [P values = 0.046, odds = 8.0 (0.88-72.1); S. aureus versus S. aureus and Pseudomonas]. Significant drug susceptibility difference between HIV+ and HIV- patients was shown by chloramphenicol with P =0.027, odds= 5.7(1.3-24.1). Thus HIV + patients are five fold likely to develop resistance to chloramphenicol as compared to HIV – patients. Conclusion: More antibiotic susceptibility studies need to be done to elucidate the pathogenic mechanisms of S. aureus that is isolated from co-infected wounds.