[Epidemiology of Clostridioides difficile carriage in maternal and infant populations: underlying determinants, molecular types, and drug resistance].

Objective

To understand the molecular types and drug resistance characteristics of Clostridioides (C.) difficile detected in the maternal and infant population in China, analyze the risk factors affecting the carriage of C. difficile in infants among maternal and infant factors.

Methods

Fecal samples and basic information of 208 mother-infant pairs were collected from four provinces, i.e. Shandong, Chongqing, Zhejiang, and Hunan. C. difficile was isolated and identified through anaerobic culture. The PCR was used for toxin gene detection and multi-point sequence typing, and the resistance to 9 drugs was determined by using E-test strips. Infants were grouped based on C. difficile carriage status, then the analysis on the risk factors affecting the carriage of C. difficile in infants among maternal and infant factors were performed.

Results

The detection rate of C. difficile in maternal samples was 3.85% (8/208) compared with 37.02% (77/208) in infant samples. Significant differences in the carriage rate of C. difficile were observed among infants with different age (P<0.001), The carriage rate in infants aged 7-12 months was high with the peak at age 11 months (66.67%, 14/21). The predominant molecular type of C. difficile detected in infants were ST54 (35.06%), ST42 (12.99%), and ST3 (11.69%). The proportion of toxigenic strains was as high as 79.22%, with the toxin gene profile predominantly being tcdA+tcdB+cdt- (75.32%). In contrast, no predominant sequence type was observed in maternal C. difficile strains, and the toxin gene profile was also primarily tcdA+tcdB+cdt- (87.50%). All the C. difficile isolates were sensitive to metronidazole, rifampicin, and vancomycin, but highly resistant to erythromycin (81.18%) and clindamycin (91.76%). The differences in C. difficile carriage rate in infants with different feeding patterns were significant (P=0.019). The lowest carriage rate was found in breastfeeding infants (25.00%, 18/72), followed by those with mixed feeding (40.00%, 34/85), while formula-feeding infants had the highest carriage rate (49.02%, 25/51).

Conclusions

The carriage rate of C. difficile in infants was relatively high in China, and the molecular typing profile and drug resistance profile were similar to those of adults. There are differences in the carriage rate of C. difficile in infants in different age groups and with different feeding patterns.