Observational study in a single institute in Japan: How many community-onset pneumonia patients would have Clostridioides difficile infections after treatment?

While community-onset pneumonia patients such as community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP) have several risk factors of Clostridium difficile infection (CDI), prognostic guidelines for pneumonia never mention the occurrence of CDI following treatment for pneumonia. For the purpose of examining the occurrence and prevalence of CDI, we reviewed all community-onset pneumonia patients who were admitted to our institute during the study period. A total of 406 patients were enrolled in this study. Among them, 257 patients (63%) were male, and the median age was 79 years (range 19-103 years). Surprisingly, 155 CAP (88%) and all HCAP (100%) patients had one or more risk factors for CDI. Furthermore, 70 CAP (40%) and 157 HCAP (69%) patients had more than 3 risk factors for CDI. Despite these facts, probiotic medication for prevention of CDI were prescribed for 12 (7%) CAP and 15 (7%) HCAP patients as the initial treatment. Finally, 3% and 9% of CAP and HCAP patients had CDI after completing the treatment for pneumonia. Regarding the duration of antibiotic therapy, 146 CAP (82%) and 176 HCAP (77%) patients received it for longer than 8 days, even though bacteremia was not confirmed in those patients. In addition, 27 CAP (15%) and 26 HCAP (11%) patients received a combination antibiotic therapy as an initial treatment. They seemed to be unnecessary. Physicians should acknowledge community-onset pneumonia has several risk factors for CDI, and should avoid a longer than necessary antibiotic therapy and unnecessary combination antibiotic therapy for pneumonia patients with risk factors for CDI.