EVALUATION OF VITRECTOMY MACHINES AS A SOURCE OF FALSE-POSITIVE CULTURE CONTAMINATION IN ENDOPHTHALMITIS

PURPOSE: We sought to determine whether a venturi-aspiration vitrectom y machine could contaminate a vitrectomy culture. METHODS: Ninety vitr ectomies were simulated in a hospital operating room and were cultured with standard techniques. An additional 90 control specimens were cul tured in the exact same manner, but the vitrectomy machine was not use d. Instead, the control specimens were placed directly into a sterile vitrectomy cassette. Contamination rates in the two groups were compar ed. RESULTS: Contamination occurred in four of 90 vitrectomy-simulatio n cultures and in three of 90 control cultures. This difference in con tamination rate was not statistically significant. CONCLUSIONS: Althou gh the result of a culture of the vitrectomy effluent can be false-pos itive, the source of contamination is not likely to be the vitrectomy machine.