Surgical site infections linked to contaminated surgical instruments

This study describes an investigation into a sudden increase in surgical site infection rate following 'clean' surgery. The outbreak involved 15 orthopaedic patients following metal insertion, and five ophthalmology patients who developed endophthalmitis.

An outbreak committee was convened in order to find the cause of the sudden increase in surgical infections.

The investigation included epidemiological and patient analyses, and environmental and clinical audits of wards and theatres. Following reports of contaminated surgical sets, surgical instruments and their packaging were examined using a standardized laboratory protocol. Clinical staff visited the sterilization plant.

Skin flora including coagulase-negative staphylococci (CoNS) and Bacillus spp. were recovered from a range of patient specimens. Eleven patients required further surgical attention. Microbiological processing of surgical packs revealed CoNS and Bacillus spp. from inner packaging as well as from instruments themselves. Inspection of the sterilization plant highlighted inadequate maintenance of autoclave components and poor handling practices by staff. This was compounded by lapses in inspection of surgical sets by theatre staff. Cases terminated following a review of operator training, supervision and staffing at the sterilization plant, in conjunction with formal inspection and reporting of damp/stained sets by theatre staff.

Post-sterilization contamination of sets containing surgical instruments was linked with an increased rate of deep surgical site infections in orthopaedic and ophthalmic patients. The investigation demonstrates the importance of close collaboration and co-operation between sterile services providers, managers and clinical staff and offers guidance for reducing the risk of contaminated sterile surgical instruments.