The analysis of the epidemic status and risk factors associated with different genotypes Clostridioides difficile mixed infection.

Background: Clostridioides difficile is the main pathogen of antibiotic-associated diarrhea and pseudomembranous enteritis. Mixed Clostridioides difficile infection are simultaneous infection of the same host with strains of different genotypes. In recent years, many studies have shown that mixed infection of pathogens may have an impact on the disease process or host immunity. Clinical screening for Clostridioides difficile mixed infection is rarely performed, which leads to underdiagnosis of mixed infection and provides the potential for subsequent recurrence. Our study focused on the occurrence of mixed infection in clinical Clostridioides difficile infection(CDI) and the impact of underlying diseases on susceptibility to mixed infection, and exploring the link between mixed infection and disease recurrence.

Results: A total of 274 CDI patients were enrolled between August, 2022 and September, 2023, 22(8.03%) were mixed infection. Cases review shows that ulcerative colitis(UC), especially chronic recurrent UC (OR = 3.792, 95% CI = 1.477-0.733; P = 0.006), may increase the risk of Clostridioides. difficile mixed infection, and heterogeneous resistance rate among mixed infection strains was 83.9%. Biofilm experiments show that the level of biofilm formation during mixed infection is tend to the more competent Clostridioides difficile strain.

Conclusions: UC may increase the risk of Clostridioides difficile mixed infection. Screening for Clostridioides difficile mixed infection is essential for patients with UC combined with CDI in order to understand the transmission chain and clinical heterogeneity, and prevent the development of multi-drug resistant strains.