Staphylococcus aureus colonization and surgical site infection in patients admitted to a South African academic hospital for elective total joint arthroplasty

Pietrzak, Jurek Rafal Tomasz
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Introduction: Peri-prosthetic joint infections (PJIs) are a major source of morbidity and mortality for patients undergoing Total Joint Arthroplasty (TJA). Staphylococcus aureus (S. aureus) colonization, either Methicillin Sensitive S. aureus (MSSA) or Methicillin Resistant S. aureus (MRSA) is an independent, modifiable risk factor for PJIs. Post-operative infections are reported to be ten times greater in S. aureus carriers than in non-carriers in developed countries though recorded data is lacking for the developing world. This study aims to determine the prevalence of S. aureus colonization in patients awaiting TJA in South Africa. Materials and Methods: We prospectively assessed 119 patients awaiting Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA) between October and December 2016. We screened three separate anatomical sites, namely the axilla, groin and anterior nares, on each patient for both MSSA and MRSA. Patients with positive cultures were treated with intra-nasal mupirocin ointment and chlorhexidine body wash. All patients were followed up for 30-, 60- and 90-days re-admissions and subsequently for a minimum of two years for any evidence of complications. Univariate and comparative statistical analyses to determine risk factors for colonization were conducted using t-test, Fisher’s exact test, and chi squared analyses. Results: The overall prevalence of MSSA-colonization was 31.9% (n=38). There were no patients colonized with MRSA. Nasal swabs returned a yield of 81.6% (n=31), with groin swabs and axillary swabs at 39.5% (n=15) and 28.9% (n=11), respectively. Eradication was successful in 94.74% (n=36) after five days treatment. All patients (100%) were decolonized after counseling and repeat eradication treatment. The overall complication rate was 7.6% (n=9). The 30-days re-admission rate in the S. aureus -colonized group was 7.9% (n=3) as opposed to 7.4% (n=6) in the non-colonized cohort. There were no 60- and 90-days re-admissions and no cases were revised at a mean follow-up of 2.26 years. Conclusion: The rate of S. aureus colonization in patients undergoing elective TJA in a developing country was 3 1.9% and is equivalent to reported rates in developed countries. We recommend that the anterior nares should always be included in the sites being analyzed for colonization. The combination of intra-nasal mupirocin ointment and chlorhexidine baths is an effective decolonization strategy for eradicating S. aureus colonization
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Medicine in Orthopaedic Surgery, 2021