Molecular characteristics of Clostridium difficile in children with acute gastroenteritis from Zhejiang.

BACKGROUND: Clostridium difficile infection (CDI) has an increasing pediatric prevalence worldwide. However, molecular characteristics of C. difficile in Chinese children with acute gastroenteritis have not been reported. METHODS: A five-year cross-sectional study was conducted in a tertiary children's hospital in Zhejiang. Consecutive stool specimens from outpatient children with acute gastroenteritis were cultured for C. difficile, and isolates then were analyzed for toxin genes, multi-locus sequence type and antimicrobial resistance. Diarrhea-related viruses were detected, and demographic data were collected. RESULTS: A total of 115 CDI cases (14.3%), and 69 co-infected cases with both viruses and toxigenic C. difficile, were found in the 804 stool samples. The 186 C. difficile isolates included 6 of toxin A-positive/toxin B-positive/binary toxin-positive (A+B+CDT+), 139 of A+B+CDT-, 3 of A-B+CDT+, 36 of A-B+CDT- and 2 of A-B-CDT-. Sequence types 26 (17.7%), 35 (11.3%), 39 (12.4%), 54 (16.7%), and 152 (11.3%) were major genotypes with significant differences among different antimicrobial resistances (Fisher's exact test, P < 0.001). The A-B+ isolates had significantly higher resistance, compared to erythromycin, rifampin, moxifloxacin, and gatifloxacin, than that of the A+B+ (χ2 = 7.78 to 29.26, P < 0.01). The positive CDI rate in infants (16.2%) was significantly higher than that of children over 1 year old (10.8%) (χ2 = 4.39, P = 0.036). CONCLUSIONS: CDI has been revealed as a major cause of acute gastroenteritis in children with various genotypes. The role of toxigenic C. difficile and risk factors of CDI should be emphatically considered in subsequent diarrhea surveillance in children from China.

Epidemiological and Genomic Characterization of Campylobacter jejuni Isolates from a Foodborne Outbreak at Hangzhou, China.

BACKGROUND: Foodborne outbreaks caused by Campylobacter jejuni have become a significant public health problem worldwide. Applying genomic sequencing as a routine part of foodborne outbreak investigation remains in its infancy in China. We applied both traditional PFGE profiling and genomic investigation to understand the cause of a foodborne outbreak in Hangzhou in December 2018. METHOD: A total of 43 fecal samples, including 27 sick patients and 16 canteen employees from a high school in Hangzhou city in Zhejiang province, were recruited. Routine real-time fluorescent PCR assays were used for scanning the potential infectious agents, including viral pathogens (norovirus, rotavirus, adenovirus, and astrovirus), and bacterial pathogens (Salmonella, Shigella, Campylobacter jejuni, Vibrio parahaemolyticus and Vibrio cholerae). Bacterial selection medium was used to isolate and identify the positive bacteria identified by molecular test. Pulsed field gel electrophoresis (PFGE), and next generation sequencing (NGS) were applied to fifteen recovered C. jejuni isolates to further understand the case linkage of this particular outbreak. Additionally, we retrieved reference genomes from the NCBI database and performed a comparative genomics analysis with the examined genomes produced in this study. RESULTS: The analyzed samples were found to be negative for the queried viruses. Additionally, Salmonella, Shigella, Vibrio parahaemolyticus and Vibrio cholera were not detected. Fifteen C. jejuni strains were identified by the real-time PCR assay and bacterial selection medium. These C. jejuni strains were classified into two genetic profiles defined by the PFGE. Out of fifteen C. jejuni strains, fourteen have a unified consistent genotype belonging to ST2988, and the other strain belongs to ST8149, with a 66.7% similarity in comparison with the rest of the strains. Moreover, all fifteen strains harbored blaOXA-61 and tet(O), in addition to a chromosomal mutation in gyrA (T86I). The examined fourteen strains of ST2988 from CC354 clone group have very minimal genetic difference (3~66 SNPs), demonstrated by the phylogenomic investigation. CONCLUSION: Both genomic investigation and PFGE profiling confirmed that C. jejuni ST2988, a new derivative from CC354, was responsible for the foodborne outbreak Illustrated in this study.

Complete genome sequence of a sapovirus from a child in Zhejiang, China.

Although Sapovirus (Caliciviridae) has been accepted as one of the causes of acute gastroenteritis worldwide, little is known about the genetic characteristics of the whole genome of sapoviruses in China, especially those that infect humans. Here we report the complete genome sequence of a sapovirus strain, Human/Zhejiang1/2015/China, obtained from a child with acute gastroenteritis in Hangzhou, Zhejiang Province, China. Samples were collected and delivered to the CDC laboratories and were detected by RT-PCR. Sanger sequencing was used to obtain the full genome and molecular characterization of the genome was determined. A phylogenetic analysis of the genome was also performed. The results indicated that Human/Zhejiang1/2015/China belongs to Genogroup I. No recombination events were detected. This is the first complete sequence from a child to be reported in China. The sequence information is important for surveillance of this emerging gastrointestinal infection.