703. Prevalence of Toxigenic and Non-Toxigenic C. difficile in Patients Admitted to an Academic-Affiliated Long Term Acute Care Hospital

Abstract Background Clostridioides difficile (C. difficile) is the leading hospital associated infection and is highly prevalent among patients admitted to long term care facilities (LTCFs). Both toxigenic and non-toxigenic strains of C. difficile colonize patients and produce spores that can persist on healthcare surfaces. Prior trials have shown that administration of non-toxigenic C. difficile can reduce recurrent C. difficile infection (CDI). We sought to estimate the prevalence of toxigenic and non-toxigenic C. difficile in a LTCF as a step toward better understanding if colonization with non-toxigenic C. difficile may be protective for CDI. Methods Patients admitted to an academic-affiliated long-term acute care facility (or their legally authorized representatives) were approached for verbal consent for collection of peri-rectal, inguinal swabs, and an environmental surface composite swab that were cultured in CCMB-TAL, a differential and selective media for C. difficile. Positive cultures underwent nucleic acid extraction and PCR with primers designed to amplify a pan-C. difficile target (rplB), C. difficile toxin (tcdB) and the conserved non-coding region carried by non-toxigenic strains instead of the Pathogenicity Locus. Results Of 43 occupied LTCF rooms, a total of 32/43 (74.4%) participants were sampled on two floors on one day. The Standard Infection Ratio (SIR) for C.difficile in the two quarters prior to sampling were 1.12 and 1.17, at the LTCF. At least one C. difficile strain was detected in 8/32 (25%) sampled patients (Fig. 1A). The estimated prevalence of toxigenic C. difficile was 5/32 (15.6%). (Fig. 1B, 1D). The estimated prevalence of non-toxigenic C. difficile was 5/32 (15.6%) (Fig. 1C, 1D). PCR-based detection of both tcdB and the conserved locus in non-toxigenic strains suggested mixed colonization with toxigenic and non-toxigenic strains in 2/32 (6.2%) patients. Fig. 1A: Estimated 25% total prevalence of C.difficile (Cdall: toxigenic and non-toxigenic combined) mapped by patient and room. Fig. 1B: Estimated 16% prevalence of toxigenic C.difficile (CdTx) mapped by patient and room. Fig. 1C: Estimated 16% prevalence of non-toxigenic C. difficile (CdNT) mapped by patient and room. Conclusion These data demonstrate that both toxigenic and non-toxigenic strains of C. difficile are prevalent in long-term care hospital patients but mixed colonization with both strains is less frequent. Further investigations are needed to determine the