Background Multiple studies have shown that antibiotic utilization increased during the COVID-19 pandemic. However, the impact of this increased utilization has not been well established. The aim of this study is to describe the trends in minimum inhibitory concentrations for various antibiotics against common gram-negative pathogens observed since the start of the COVID-19 pandemic as compared to previous years. Methods This retrospective study was conducted at the Memphis VA. All respiratory, urine, and blood culture MicroScan results run from October 2017-March 2021 were analyzed. Only inpatient and emergency department data was included. The MIC50 and MIC90 of seven antibiotics for four of the most common pathogens were trended by quarterly intervals. Results MIC50 and MIC90 were compared using standardized breakpoints. As compared to previous years, Pseudomonas aeruginosa was noted to have the most sustained increase in MIC90 across various antibiotics. In the last 3 quarters of the study time frame, piperacillin-tazobactam mean MIC90 increased from 32 to 64, cefepime from 8 to > 16, and meropenem from 4 to > 8. Escherichia coli had a sustained increase in ceftriaxone MIC90 from < 1 to > 8 in the final quarter of 2020 and beginning of 2021. Klebsiella pneumonia was also found to have a sustained increase in cefepime mean MIC90 from < 1 to > 16 during the year of 2020, with return to previous MIC90 the following quarters. Conclusion Previous studies have clearly demonstrated a widespread increase in antibiotic utilization during the COVID era. Our study demonstrates how even short-term increases in antibiotic use can lead to shifts in MIC, if not outright resistance. This was demonstrated across multiple common gram-negative pathogens and to various broad-spectrum antibiotics which were commonly used more frequently during COVID-19. Further analysis will be needed to determine whether these trends continue or whether the decrease in antibiotic utilization in the recent months will lead to similar decrease in MIC. Disclosures All Authors: No reported disclosures

Background Procalcitonin (PCT) is an inflammatory biomarker that can be helpful for early detection of certain types of infections and can be a useful tool to decrease unnecessary antibiotic (abx ) exposure. However, its use among clinicians remains variable. The aim of this study was to elucidate current practices at a selection of Veteran’s Administration medical centers. Methods The VISN-9 Antimicrobial Stewardship Collaborative distributed a 15-question survey electronically to providers at all five VA medical centers in VISN-9 between 1/15/22 to 3/31/22 to clinicians practicing in the acute care, ICU and ED settings. Information on level of training, primary site as well as current practices and beliefs about PCT were collected. Responses were tabulated as percentages for this cross-sectional study. Results 99 providers completed the survey with two centers comprising 83% of responses. 44% of respondents were attendings. The Figures illustrate some interesting variability in the use of PCT. Figure 1 reveals more than half of residents but less than a quarter of attendings ordered PCT on admission for patients with suspected infection. Figure 2 shows similar use of PCT by attendings and residents to initiate abx, however, residents used PCT much more than attendings to justify continuation of abx, and residents used PCT somewhat more than attendings to de-escalate abx. Only one clinician ordered PCT daily. Figure 3, ordering practices by disease state, shows similar trends between the two groups. 44% of all respondents felt somewhat comfortable whereas 22% felt somewhat uncomfortable interpreting PCT results. Some of the interesting comments from respondents included: “PCT is “ordered too often and indiscriminately”; “I never know what to do with it”; and “I usually allow my patients to complete their abx courses rather than discontinuing abx earlier”. Conclusion Using PCT to help guide abx use can help minimize unnecessary abx exposure which may help to stem the increase in antimicrobial resistance. This survey indicates that many clinicians are unsure of when to use PCT, how often to order it, and whether it is a reliable enough tool on which to base treatment decisions. Further education will be necessary to help inform best practices. Disclosures All Authors: No reported disclosures.