502. Enhanced Sporulation and Vancomycin Resistance Associated With Clostridium difficile From Recurrent Infections

BACKGROUND: Recurrent Clostridium difficile infection (R-CDI) remains a significant healthcare problem. Our aim was to analyze sporulation and antimicrobial resistance of C. difficile in biofilms as a potential reservoir for recurrence. METHODS: C. difficile isolates obtained from patients with initial CDI (I-CDI) (n = 93) and from patients with R-CDI (n = 39) were analyzed. Isolates were identified by PCR and MALDI-TOF MS and ribotyped using 16S RNA amplification and capillary electrophoresis. Biofilm production was assessed by the crystal violet microtiter-plate method. Susceptibilities to vancomycin and linezolid were determined both in planktonic and in biofilm cells and total viable cells and spore were quantified in biofilm cells. RESULTS: All I-CDI and R-CDI isolates were biofilm producers and >75% were ribotype 027. MICs for vancomycin and linezolid were higher in biofilm than in planktonic cells in both I-CDI and R-CDI isolates (P < 0.05) (Table 1). Isolates recovered from R-CDI showed a higher vancomycin resistance (MIC >2 mg/L) and sporulated 2 log(10) higher than isolates from I-CDI (P < 0.01 and P = 0.086, respectively). CONCLUSION: C. difficile isolates in biofilms were 100-fold more resistant to vancomycin than planktonic cells. Isolates recovered from patients with R-CDI showed higher sporulation capacities than C. difficile recovered from I-CDI patients. Our data suggest that biofilm formation ability may play a key role in R-CDI by contributing to vancomycin resistance/tolerance. Furthermore, C. difficile from recurrent episodes sporulated to a greater capacity which may facilitate prolonged C. difficile persistence in the gut following therapy for R-CDI. DISCLOSURES: All authors: No reported disclosures.