This study assessed microbiological safety of water from public swimming pools in Guangzhou, China. Water samples from 39 outdoor municipal swimming pools were collected from late June to early September, 2013 and subjected to detection of protozoa (Giardia and Cryptosporidium) and bacteria (Pseudomonas aeruginos, total coliforms, E. coli, E. coli O157, Shigella, and Salmonella). Cryptosporidium and Giardia were both detected in 5 (12.8%) swimming pools. Total coliforms were detected in 4 (10.3%) samples with concentrations ranging from 1.3 to 154.0 MPN/100 mL while E. coli was detected in 4 (10.3%) samples with concentrations ranging from 0.5 to 5.3 MPN/100 mL. P. aeruginosa was detected in 27 (69.2%) samples but E. coli O157, Shigella and Salmonella were not detected. Among these swimming pools, 9 (23%) met the Chinese National Standard of residual chlorine levels and 24 (62%) were tested free of residual chlorine at least once. The multi-locus sequence typing (MLST) analysis showed that all P. aeruginosa isolates belonged to new sequence types (STs) with dominant ST-1764 and ST-D distributed in different locations within the area. Some P. aeruginosa strains were resistant to medically important antibiotics. Results indicate potential public health risks due to the presence of microbiological pathogens in public swimming pools in this area.

This study quantified the association of rodent fruit damage and the microbiological quality of irrigation water on the risk of microbiological contamination of strawberries collected from 18 U-pick farms across five different districts in the Guangzhou metropolitan region of southern China. Fifty-four composite strawberries samples, with or without evidence of rodent or avian foraging damage (i.e., bitten), along with 16 irrigation water samples, were collected during the spring of 2014 and winter of 2015 from our cohort of 18 farms. Composite strawberry samples and irrigation water were analyzed for total coliforms, E. coli, Salmonella, E. coli O157, Giardia, and Cryptosporidium. Total coliforms and E. coli were detected in 100% and ~90% of irrigation water samples, respectively. In contrast, Cryptosporidium was detected in only two water samples, while Salmonella, E. coli O157, and Giardia were not detected in any water samples. Strawberries with signs of being bitten by wildlife had significantly higher concentrations of total coliforms and E. coli, compared to strawberries with no physical evidence of rodent damage (p < 0.001). Similarly, Cryptosporidium was detected in 7/18 (39%) of bitten, 4/18 (22%) of edge, and 5/18 (28%) of central strawberry samples, respectively. Concentration of E. coli on strawberries (p < 0.001), air temperature (p = 0.025), and presence of Cryptosporidium in irrigation water (p < 0.001) were all associated with the risk of Cryptosporidium contamination on strawberries. Salmonella and Giardia were detected in <4% strawberry samples and E. coli O157 was not detected in any samples. These results indicate the potential food safety and public health risks of consuming unwashed strawberries from U-pick farms, and the need for improved rodent biosecurity of U-pick strawberry fields and enhanced microbiological quality of irrigation water used at these facilities.

Bovine coronavirus (BCoV), bovine norovirus (BNoV), and bovine rotavirus C (BRVC) are common diarrheal viruses in cattle and pose significant threats to herds and humans. In this study, we collected 194 fresh fecal samples from adult cattle between September 2022 and January 2024 in Guangdong Province, China. We presented the genetic characteristics of 24 newly identified enteric virus strains in cattle, including two bovine coronavirus (BCoV) strains (GD-GZ-01 and GD-GZ-02), one bovine norovirus (BNoV) strain (BYN7), and 22 bovine rotavirus (BRV) strains (BRVB, BRVC, and BRVH, representing groups B, C, and H, respectively). Genetic analysis was conducted via MEGA-X, MAFFT, RDP, SimPlot and Rstudio software. The reference strains’ related genes were retrieved from GenBank for comparison and analysis via MegAlign and Snapgene. The detection rates for BCoV, BNoV, and BRVC were 8.76% (17/194), 15.98% (31/194), and 5.67% (11/194), respectively. The phylogenetic and homology analyses showed that BCoV strains GD-GZ-01 and GD-GZ-02 were branched Chinese Zhejiang or Xinjiang strains from the Betacoronavirus group; BNoV strain BYN7 contains new gene sequences, the VP1 and VP2 genes, from the GIII.2 subgroup and may have originated from Chinese Sichuan yaks strain; The 22 BRV rotavirus strains (10 BRVB strains, 11 BRVC strains, and one BRVH strain) formed distinct phylogenetic clusters respectively. Additionally, BCoV strains have a close genetic relationship with the human OC43 strain. Furthermore, recombination analysis of the S genes showed that recombination events may have occurred between the bovine GD-GZ-01 and the human OC43 strain. BCoV, BNoV, and BRVC exhibited relatively low prevalence levels in Guangdong, China. This is the first study to report the infection rate and genetic characterization of BRVC strains circulating in cattle in China. Our study confirmed that there were disparities in the infection rate regarding sampling site type. Genetic characterization suggested that the identified BCoV strains (GD-GZ-01 and GD-GZ-02) may have originated from Zhejiang or Xinjiang, BNoV (BYN7) could be a novel genetic variant from a Sichuan yak strain, and 22 BRV strains are novel genetic variants in new clusters. And, recombination events between the bovine GD-GZ-01 and the human OC43 strain suggested potential risks of zoonosis. It suggested potential risks of cross-regional and cross-species transmission of these viruses.

The recent Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic highlights the significant threat coronaviruses (CoVs) pose to public health. With their extensive cross-continental movements, migratory birds have the potential to serve as reservoirs and vectors for CoVs. This study aimed to investigate the prevalence of CoVs in birds in densely populated areas of Guangdong Province, China. Of the 128 samples collected from birds, six tested positive for CoVs (4.7%, 95% CI: 1.7–9.9%), and three complete viral genomes were obtained through viral metagenomics and PCR. Phylogenetic analysis revealed that two CoVs (MD_XN18 and SG_DWY40) belonged to the Gammacoronavirus genus, while one (CP_XN11) belonged to the Deltacoronavirus genus. Homology analysis revealed that the MD_XN18 strain discovered in mallards shares 95.6–97.4% sequence similarity with chicken infectious bronchitis viruses (IBVs), providing direct evidence that migratory mallards can transmit avian IBVs. Recombination analysis suggested that two genomic regions of SG_DWY40 could originate from unknown sources through recombination, potentially leading to the expression of a novel viral protein, provisionally named NS3.5. These findings underscore the ongoing transmission and evolution of CoVs among birds in cities near Guangdong Province, emphasizing the need for continued monitoring and research.

Background Campylobacter spp., as a zoonotic pathogen, has been one of the most common pathogens that causes human gastroenteritis in developing countries. The objective of this study was to determine the antibiotic resistance of Campylobacter in children. Methods Stool samples were collected from pediatric patients under 14 years of age who visited hospital for acute diarrhea between February 2018 and January 2019. Campylobacter was isolated from samples using selective enrichment and culture and confirmed by PCR, genotypes were characterized by multilocus sequencing, and antibiotic resistance was determined by susceptibility and resistance genes to antimicrobials of medical importance. Results The overall prevalence of Campylobacter in children with diarrhea was 4.4% (53/1197). Higher prevalence was observed in children under five-year-old and in spring and autumn. Approximately 80% (42/53) of confirmed isolates were C. jejuni and ~ 20% (11/53) isolates were C. coli. Among the 51 isolates successfully typed, 43 sequence types belonging to 13 clonal complexes were identified, of which 44.2% (19/43) sequence types were novel. The majority of the Campylobacter isolates (74%) exhibited multidrug resistance and the most common antimicrobials resistant to were ciprofloxacin, tetracycline and nalidixic acid. All isolates (53/53) were positive of the tet(O) gene that confers resistance to tetracycline and the gyrA gene that confers resistance to quinolones/fluoroquinolones, 81% (43/53) isolates were positive of the ermB gene that confers resistance to macrolides, and 19% (10/53) isolates were positive of the aadE-sat4-aphA gene that confers resistance to aminoglycosides, respectively. Conclusions Despite the low prevalence of Campylobacter in children in the subtropical Guangzhou metropolitan, the high multidrug resistance of diverse MLST of Campylobacter indicated the importance of preventive strategies including routine surveillance in order to minimize the infections of antibiotic resistant Campylobacter in children.