Lau, J.

Abstract Background Automated plating instruments have been shown to improve quality in Microbiology laboratories in a number of ways including consistent streaking patterns that provide better isolation of bacterial colonies compared to manual methods. The time per culture set up and automated camera imaging is dependent upon the amount of media set, such that more individual plates slow down turn around time. Conversely, smaller media surface area and the use of non-selective media may result in mixed colonies that require sub-culture for isolation before identification and susceptibilities can be performed. Based upon these findings, we attempted to reduce our media usage per culture with the implementation of automation, with the goal of using as few plates as possible while at the same time not negatively impacting the turn around time of the culture via the need to subculture poorly isolated colonies. We conducted a pre-and post-implementation study evaluating the costs per culture and turn around time delays related to subculturing in a subset. Methods In the pre-implementation period, from April-January 2023, three individual media plates (sheep blood agar, chocolate agar and CNA/MacConkey bi-plate) were routinely set for general aerobic bacterial culture sources including swabs and body fluids. In the post implementation period, from April-January 2024, a single sheep blood/chocolate agar bi-plate was set unless the gram stain showed evidence of mixed organisms (defined as more than one morphology) at which time a secondary selective media (CNA/MacConkey) was manually set. For urine cultures, in the pre-implementation period 2 plates were set (sheep blood and CNA/MacConkey bi-plate) and in the post-implementation period a single chromogenic agar/sheep blood bi-plate was set. Total numbers of cultures in both periods were collected as well as the number of cultures for which additional media were set based on gram stain results. Orders of subculture media in the laboratory information system were compared per positive cultures. Statistical analysis was performed in GraphPad Prism. Results In the pre- versus post-implementation periods, a total of 16,454 vs 17,782 general aerobic cultures and 50,680 vs 53,916 urine cultures were set, respectively. Only 3.6% of general cultures required additional media set based on gram stain. The difference in cost between pre- and post-implementation was approximately a two-thirds reduction in cost for general cultures and a 25% reduction for urine cultures, with a total savings of approximately $34,238 in media avoidance in the post-implementation period. The frequency of positive cultures requiring subculture was not significantly different between the pre- (average 36% of positive growth) and post-implementation (average 22% of positive growth) periods for both culture types and may actually have been reduced due to automation. Conclusions The implementation of reduced media concomitant with streaking via automation resulted in significant cost savings while not negatively impacting isolation, which in turn impacts culture turn around times. The automation may have reduced need for subculture, perhaps due to better isolation, thus subsequent analyses will explore this additional finding.

Abstract Introduction/Objective Our laboratory implemented a full COPAN WASPLab microbiology automation line in March of 2023. Prior to this implementation, our laboratory routinely observed potential bacterial contamination of sterile specimens, as well as culture plates in which the specimens were not struck out, due to a large number of new staff members and heavy workloads. Both of these quality issues directly impact patient care due to potential misleading or delayed results. We hypothesized that automation of the plating and incubation steps would reduce both of these quality issues significantly. Methods/Case Report Potential contamination and plates not struck were self-reported by technologists during pre- implementation (July 2022-Feb 2023) and post-implementation (Mar-Apr 2023) periods. Potential contamination was defined as one or two colonies of bacteria on a single agar plate, consistent with skin fora, from a normally sterile source specimen and reviewed by the Director for potential clinical correlation. Plates unstruck in the post- implementation period continued to include those manually set up. A 2 two proportion z-test was performed to compare pre and post implementation data. Results (if a Case Study enter NA) A total of 3,055 and 1,750 sterile source cultures were analyzed in the pre- and post-implementation periods, respectively. Of these, 109 versus 8 were designated as potential contamination, respectively, resulting in a significant reduction (Z stat 6.7, p<0.0001). For the plate streaking portion, 22,814 and 7,211 cultures were analyzed in the pre- and post-implementation periods, respectively. Of these, 21 versus 3 plates were not struck, respectively, resulting in a greater than 2-fold reduction per culture, but did not meet significance. Conclusion Implementation of microbiology automation significantly reduced skin flora contamination of sterile source cultures. Proportions of unstruck plates were also reduced, although these did not meet significance, likely due to the low numbers.