Foodborne Viruses and Somatic Coliphages Occurrence in Fresh Produce at Retail from Northern Mexico.

Foodborne disease outbreaks linked to consumption of vegetables have been often attributed to human enteric viruses, such as Norovirus (NoV), Hepatitis A virus (HAV), and Rotavirus (RoV). Information about the occurrence of these viruses is scarce in many fresh-producing countries. Viral contamination detection of indicators, such as somatic coliphages, could indirectly reflect the presence of viral pathogens, being a valuable tool for better viral risk assessment in food industry. This study aimed to establish the occurrence and correlation of foodborne viruses and somatic coliphages in leafy greens in northern Mexico. A total of 320 vegetable samples were collected, resulting in 80 composite rinses, 40 of lettuce and 40 of parsley. Somatic coliphages were determined using the EPA 1602 method, while foodborne viruses (HAV, RoV, NoV GI, and GII) were determined by qPCR. The occurrence of RoV was 22.5% (9/40, mean 2.11 log gc/g) in lettuce and 20% (8/40, mean 1.91 log gc/g) in parsley. NoV and HAV were not detected in any samples. Somatic coliphages were present in all lettuce and parsley samples, with mean levels of 1.85 log PFU/100 ml and 2.28 log PFU/100 ml, respectively. Spearman analysis established the correlation of somatic coliphages and genomic copies of RoV, resulting in an r2 value of - 0.026 in lettuce and 0.349 in parsley. Although NoV or HAV were undetected in the samples, the presence of RoV is a matter of concern as leafy greens are usually eaten raw, which poses a potential risk of infection.

Norovirus Is the Most Frequent Cause of Diarrhea in Hospitalized Patients in Monterrey, Mexico.

Little information is available regarding the pathogens that cause diarrhea in hospitalized patients who also have various clinical problems. The purpose of this study was to determine the presence of pathogens in fecal samples of hospitalized patients all suffering diarrhea in addition to other problems in Mexico. Diarrheic stools from 240 patients were obtained in a third-level hospital in Monterrey, Mexico. PCR was used for the detection of Salmonella spp., Shigella spp., Campylobacter spp., Yersinia spp., Aeromonas spp., Clostridioides difficile, and norovirus GI and GII. The presence of trophozoites, cysts of protozoa, eggs, and/or helminth larvae was determined by microscopic observation. Of the 240 patients analyzed, 40.4% presented at least one of the pathogens analyzed. Norovirus was the pathogen most frequently found (28.6%), followed by bacteria (11.7%), and parasites (8.3%). The majority of co-infections were parasites + norovirus, and bacteria + norovirus. Norovirus was detected mainly in children aged 0 to 10 years (9/15, 60%). Patients aged 0-20 years did not present co-infections. Entamoeba coli and Entamoeba histolytica were the most common parasites, (8/240), and Salmonella was the most prevalent bacteria (10/240). This information can help design specific strategies useful for hospitalized people with a compromised status.