Abstract
This study compared manual workup of urine clinical samples with fully automated WASPLab processing. As a first step two different inocula (1 and 10 μl) and different streaking patterns were compared using WASP and InoqulA BT™ instrumentation. A 10 μl inoculum produced significantly more single colonies than a 1 μl inoculum and automated streaking yielded significantly more single colonies as compared to manual streaking on whole plates (p<0.001). In a second step, 379 clinical urine samples were evaluated using WASP and manual workup. Average numbers of detected morphologies, recovered species, and CFU/ml of all 379 urine samples showed excellent agreement of WASPLab and manual workup. The percentage of clinical categorization of urine samples as "positive" or "negative" did not differ between automated and manual work-flow but within the positive samples automated processing by WASPLab resulted in the detection of more potential pathogens. In summary, the present study demonstrates that i) the streaking pattern, i.e. primarily the number of zigzags/length of streaking lines, is critical for optimizing the number of single colonies yielded from primary cultures of urine samples, ii) automated streaking by the WASP instrument was superior to manual streaking regarding the number of single colonies yielded, (for 32.2%) iii) automated streaking leads to higher numbers of detected morphologies (for 47.5%), species (for 17.4%) and pathogens (for 3.4%). The results of this study point to an improved quality of microbiological analyses and laboratory reports when using automated sample processing by WASP and WASPLab.
Quiblier, Chantal