High-Level Resistance of Toxigenic Clostridioides difficile Genotype to Macrolide-Lincosamide- Streptogramin B in Community Acquired Patients in Eastern China

BACKGROUND: Clostridioides difficile resistant to macrolide-lincosamide-streptogramin B (MLS(B)) has not been reported in China. METHODS: In a cross-sectional study in two tertiary hospitals, C. difficile isolates from stool specimens from community-onset, hospital-associated diarrheal patients were analyzed for toxin genes, genotype, and antibiotic resistance, and the patients’ clinical charts were reviewed. RESULTS: A total of 190 (15.2%) isolates (102 A(+)B(+) and 88 A(−)B(+)) from 1250 community acquired (CA) patients were recovered and all were susceptible to vancomycin and metronidazole. High-level resistance (minimum inhibitory concentration > 128 mg/L) to erythromycin and clindamycin was recorded in 77.9% and 88.4% of the tested isolates, respectively. Furthermore, 89.3% (159/178) of the isolates resistant to MLS(B) carried the erythromycin resistance methylase gene (ermB). The statistically significant factors associated with C. difficile infection (CDI) induced by A(−)B(+) isolates with MLS(B) resistance included a severity score of >2 (odds ratio [95% confidence interval], 7.43 [2.31–23.87]) and platelet count (cells × 10(9) cells/L) < 100 [5.19 (1.58–17.04)]. The proportion of A(−)B(+) increased with enhanced CDI severity (x(2) = 21.62, P < 0.001), which was significantly higher than that of ermB-positive A(+)B(+) in severity score of 4 (x(2) = 8.61, P = 0.003). The average severity score of ermB-positive isolates was significantly higher than that of ermB-negative isolates in A(−)B(+) (Z = −2.41, P = 0.016). CONCLUSION: The ermB-positive A(−)B(+) C. difficile with MLS(B) resistance is described for the first time as a potential epidemic clone inducing severe CDI in CA diarrheal patients in Eastern China.