Abstract

*Kwashie Ajibade Ako-Nai, Olubunmmi Titi Attah and A. I. Akinyoola

ABSTRACT

Background: This study determined the effects of host, bacteria and environmental factors on the outcome of clean orthopedic wounds, antibiotic resistance profiles of selected bacterial isolates recovered from host and the environment, the operating room and the ward at Obafemi Awolowo University Hospitals Teaching complex, Ile-Ife. This was with a view to identify the factors associated with post-operative wound infections. Material and method: Seventy five (75) subjects with clean orthopedic wounds were recruited. Swabs were obtained from the surgical site before skin preparation, at incision, post incision and from the surgical site at the emergence of infection using sterile cotton- tipped applicators. Each applicator was inoculated into freshly prepared thioglycolate broth and incubated aerobically at 37OC for 48h. A loopful of culture was streaked on different bacteriologic media and isolates characterized by conventional methods. Settle plates containing different bacteriologic media were also exposed at strategic locations in the theatre for the period of each surgical procedure as well as under the patient’s bed on return of patient to the ward after the surgical procedure. Randomly selected bacterial isolates were screened by disk diffusion for antibiotic susceptibility using seventeen different antibiotics. Data generated from the study were analyzed using student’s t-test (paired and unpaired), ANOVA and CHI square. Correlation analyses were used to show linear relationship between resistance patterns of various bacterial isolates to the different antibiotics. Results: Altogether, 162 bacterial isolates were recovered; one hundred and fifty six (156) from the operative site comprising of 68 from pre incision, 36 at incision and 52 from post incision sites while the last six (6) were from the three (3) patients with post-operative infection. The predominant isolates from both operative site and the infected site were Staphylococcus aureus, and Corynebacterium pseudodiphtheriticum. Two hundred and ninety one (291) bacterial isolates were recovered from the settle media plates exposed at four strategic locations in the operating room. Sixty-one (61) from location 1, 73 from location 2, 79 from location 3 and 78 from location 4. The predominant isolates were Bacillus subtilis, Corynebacterium jeikeium, Staphylococcus aureus and Corynebacterium pseudodiphtheriticum. Fifty (50) bacterial isolates were recovered from the ward environment; mainly B. subtilis, C. pseudodiphtheriticum and S. aureus. Conclusion: The study revealed high level of multiresistance in bacterial isolates from both the host and the environment. The results also identified some factors that predict post-operative infection tho?gh some were not statistically significant in this study. Six Staphylococcus aureus strains were subjected to RAPD – PCR to determine relatedness while thirty of the isolates were screened to detect resistance and virulence genes. The incidence of post-operative infection in clean orthopaedic wound in this study was 4%. Staphylococcus aureus was the commonest pathogen in the study.