SOURCE OF AN EPIDEMIC IN AN ORTHOPAEDIC SURGERY UNIT DISCLOSED BY AN UNCOMMON ANTIBIOTIC SUSCEPTIBILITY PATTERN OF THE CAUSAL STAPHYLOCOCCUS AUREUS STRAIN

Abstract

Purpose: Operative site infections can have catastrophic consequences after orthopaedic surgery. Prevention is particularly difficult due to the large number of factors involved. We describe here an exceptional epidemic of meti-R Staphylococcus aureus (MRSA) operative site infections whose source was successfully identified and eradicated.

Material and methods: The epidemic affected seven patients who underwent orthopaedic surgery during a thirteen-month period. All patients developed acute MRSA operative site infection. The epidemic nature of the infections was confirmed by the bacteriological study which identified the causal germ as a specific MRSA strain very different from strains generally identified in hospital infections. The causal strain was sensitive to quinolones and resistant to amikacin. Antibiotic therapy prescribed in all cases was combined with surgical lavage in four patients. Search was undertaken to identify an environmental or human source. An audit of the operating theatre was performed and nasal swabs were obtained from all personnel present at the last operation complicated by operative site infection. One non-medical assistant was found to be a carrier of the same MRSA strain incriminated as the cause of the epidemic. Nasal application of mupirocin successfully eradicated the carrier-state. No new case of operative site infection was noted for more than fourteen months.

Discussion: Operative site infections in orthopaedic surgery led to longer inpatient care and can compromise functional outcome. These nosocomial infections have a significant impact on mortality and constitute a major cost burden for hospitals. Prevention, control and treatment of MRSA nosocomial infections is a major challenge in hospitals throughout the world. Most operative site infections are caused by direct contamination during the operation. This epidemic highlights the importance of strict application of rigorous preventive measures not only by the surgical team but also by all healthcare workers and hospital personnel in general.

Conclusion: The specific antibiotic susceptibility pattern of a Staphylococcus aureus strain incriminated in several operating site infections enabled identification of the source of the epidemic and its eradication.