INVESTIGATIONS OF THE BACTERIOLOGICAL FACTORS IN CERVICAL DISK SURGERY

A study was undertaken to evaluate the potential risk of wound infecti on in cervical disk disease, the appropriateness of the current prophy lactic regimen of intravenous cefazolin at Good Samaritan Hospital, an d the increasing resistance of coagulase-negative staphylococci in nos ocomial infections. In addition, the methodology used in three prior s tudies was used to verify that double-gloving is a more effective barr ier to bacterial contamination than single-gloving and that topical st reptomycin lavage is superior to constant irrigation with plain saline . No wound infections were documented in the 40 patients who underwent cervical disk surgery in a 12-month period. Coagulase-negative Staphy lococcus species were the most common bacterial isolate, but only 20% were resistant to cefazolin. Of the 11 S. aureus isolates, 9 were sens itive to cefazolin and 2 were methicillin resistant. A remarkable 95% (114/120) of the intraoperative wound cultures were free of bacteria. In only 2 cases was there a serial increase in colonies of the same or ganism over the course of the operation. There was one positive glove culture-coagulase-negative Staphylococcus sensitive to cefazolin. The patient's skin was identified as the source of contamination in 3 intr aoperative cultures of the wound and 2 cultures of the ambient operati ng room air. Neither individual biotyping of bacteria nor antimicrobia l susceptibility testing uncovered any consistent source or pattern to account for the organisms in the surgical wound or ambient operating room air. Bacteria resistant to cefazolin were found in 36% of the int raoperative environmental cultures but in only 16% of the isolates fro m patients' skin. The decision of the neurosurgical service at Good Sa maritan Hospital was to continue a single parenteral dose of cefazolin and to add topical streptomycin to the regimen of antimicrobial proph ylaxis.