Analysis of the Correlation Between Antimicrobial Consumption and Incidence of Clostridium Difficile Infection in an Onco-Hematology Unit

Clostridium difficile infection (CDI) is an important cause of diarrhea associated with antimicrobial (AM) use. Broad-spectrum antimicrobials are associated with risk of C. difficile overgrowth. Monitoring AM consumption is essential to prevent this infection. To evaluate the temporal trend and correlation between consumption of meropenem, ceftazidime-avibactam, and piperacillin-tazobactam and CDI incidence density between January and May in an onco-hematology unit of a hospital in São Paulo. Descriptive observational study based on monthly antimicrobial consumption. (AMC) data (DOT/100 patient-days) and CDI density (cases/1,000 patient-days). Monthly data from January to May were analyzed. The analysis considered temporal trends and parallel variation relationships between indicators. CDI incidence density ranged from 0.00 to 2.75 cases per 1,000 patient-days in the period. There were no cases in January and March (0.00), and the highest values were in February (2.75) and in April and May (2.44). Monthly DOTs showed reduced meropenem consumption (from 54.45 to 19.07) and increased ceftazidime-avibactam (peak 27.20 in February and values above 20 in April and May) and piperacillin-tazobactam (from 14.25 to 10.27). The absence of cases in January and March coincided with lower consumption of the three antimicrobials, especially ceftazidime-avibactam (6.62 in March). However, increases in incidence in February, April, and May occurred in parallel with increased use of ceftazidime-avibactam and piperacillin-tazobactam. The trend suggests an association between increased AMC and higher CDI incidence. Although the data are descriptive and do not allow causal inference, the temporal relationship is consistent with CDI induction risk. The analysis suggests that increased use of broad-spectrum antimicrobials, especially ceftazidime-avibactam and piperacillin-tazobactam, may be related to CDI incidence. This reinforces the importance of rational use of these agents alongside case monitoring.