First evaluation of the WASP, a new automated microbiology plating instrument.

Many laboratories are experiencing growing shortages of trained microbiology technologists and technicians. Consequently, there is considerable interest in new automation that could potentially lessen labor demands for specimen processing. In this study, we present the first published evaluation of a new microbiology instrument, the Walk Away Specimen Processor (WASP), manufactured by Copan, Inc., in which we evaluated cross-contamination, the accuracy of plating, and the quality of the results. The absence of cross-contamination was demonstrated by plating a total of 200 alternating inoculated and sterile specimen tubes. The ability of the WASP to subculture enrichment broths was evaluated with 106 Lim broth specimens, with the results being identical to those obtained by testing by routine methods. Plating of urine specimens with the WASP was compared to plating with the Dynacon Inoculab instrument. Three hundred specimens were plated in duplicate on both instruments with 1-microl loops, and 293 specimens were plated in duplicate on both instruments with 10-microl loops. The results of duplicate plating with the same instrument (replicate plating) and of the consensus agreement between the two instruments were compared. The replicate plating results were comparable for both instruments, while the WASP had more specimens with significant results than the Inoculab with the 1-microl loop only. Lastly, for the plating of 113 specimens in ESwab tubes, the manual method and WASP plating each yielded 90 potential pathogens. In summary, we report the first evaluation of a new microbiology specimen-plating instrument, the WASP, which offers opportunities for the automated plating of microbiology specimens to an extent that has not been possible to date.

Timing of specimen collection for blood cultures from febrile patients with bacteremia.

Bloodstream infections are an important cause of morbidity and mortality. Physician orders for blood cultures often specify that blood specimens be collected at or around the time of a temperature elevation, presumably as a means of enhancing the likelihood of detecting significant bacteremia. In a multicenter study, which utilized retrospective patient chart reviews as a means of collecting data, we evaluated the timing of blood culture collection in relation to temperature elevations in 1,436 patients with bacteremia and fungemia. The likelihood of documenting bloodstream infections was not significantly enhanced by collecting blood specimens for culture at the time that patients experienced temperature spikes. A subset analysis based on patient age, gender, white blood cell count and specific cause of bacteremia generally also failed to reveal any associations.