ABSTRACT
Background. Procalcitonin (PCT) can be elevated with certain bacterial infections. Debate continues as to how to best use this biomarker to guide antibiotic use. The primary objective of this study was to evaluate the correlation of PCT levels and the presence of bacterial infection on admission in the total population and in different disease states. Methods. This was a multicenter retrospective cross-sectional study of patients admitted with specified infectious diagnoses to two VA Medical Centers from 4/1/ 2019 to 7/1/2021. Patients were stratified into 4 cohorts for analysis;those with COVID-19, sepsis from respiratory source-(S-R), sepsis from non-respiratory source (S-NR), and respiratory source without sepsis (R). Electronic medical records were reviewed to collect the following: initial procalcitonin, cultures, SIRS criteria, comorbidities (CKD, ESRD, HF, immunosuppressed, surgery within the 7 days), and c-reactive protein. PCT elevation was defined as >=0.25 ng/mL. The frequency of positive cultures within 72 hours was evaluated for patients with elevated and normal PCT levels to determine the diagnostic performance of PCT overall and for each cohort. Results. 632 of 664 patients were evaluated in this study. PCT is elevated twice as often in the septic groups as compared to the non-septic groups (figure 1). Positive predictive value (PPV) varies from 27% to 63% as compared to negative predictive value (NPV) 53%-79% among the disease state groups (figure 2). Although small numbers, the NPV of PCT improves to 83% in patients with elevated temperature and white blood cells (WBC) (figure 3). Conclusion. The findings that NPV of PCT appears to be better than PPV, support current recommendations against using this as a diagnostic tool, but rather as a tool to assist with antibiotic de-escalation. Further studies are necessary to confirm whether there are specific markers such as temperature or WBC which may improve the NPV. Our data suggests PCT is less helpful in identifying the presence or absence of bacterial infection in septic versus non-septic patients. (Figure Presented).
ABSTRACT
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.