Microbiology of post-operative wound infection in implant surgery

Abstract

Background: Open reduction and internal fixation (ORIF) of fractures with implants and prosthesis has become the first line in the management of fractures in most trauma centres. Incidentally, this is associated with post-operative wound infection which is accompanied by significant morbidity, cost and mortality. The objective of this paper was to identify the pattern of the bacteriological isolates responsible and their antimicrobial sensitivity
Method: We prospectively studied two hundred and fifty-four patients who had ORIF with implants and prosthesis that fulfilled a set of inclusion criteria. Post-operative wound infection was diagnosed based on the criteria of the National Research Council and follow-up was for twelve weeks. Aerobic and anaerobic cultures were carried out on each specimen.
Results: Two hundred and fifty-four patients were recruited and 19 had post-operative wound infection. The infection rate was 7.5%.Plates and screws were the commonest implant. Thirty-six bacterial isolates were recovered. Staphylococcus aureus was the commonest in 16 cases (44%), Bacteroides fragilis 4(11%), Escherichia coli 4(11%), Proteus spp.4 (11%).Others were Pseudomonas spp, Klebsiella spp. and Peptostreptococcus. Cephalosporins were found to be the most potent against Staphylococcus aureus while the anaerobes responded favourably to metronidazole.
Conclusion: Staphylococcus aureus remains the most important microorganism responsible for POWI in implants and prosthesis. Resistant strains have emerged and previously reserved drugs have become first line. Anaerobic organisms remain important isolates were such are feasible. Metronidazole should be a component of the antibiotic regimen where such cultures are not feasible.