Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen emerging in hospitals as well as community and livestock. MRSA is a significant and costly public health concern because it may enter the human food chain and contaminate milk and dairy products causing foodborne illness. This study aimed to determine the occurrence and the characteristics of MRSA isolated from 3760 samples of milk and dairy products in a previous survey conducted in southern Italy during 2008-2014. Overall out of 484 S. aureus strains isolated, 40 (8.3%) were MRSA and were characterized by spa-typing, Multi-Locus Sequence Typing, SCCmec typing, Staphylococcal enterotoxins (SEs) genes, Panton-Valentine Leukocidin (PVL) genes and ability to form biofilm. The most frequently recovered STs were ST152 (t355-67.5%), followed by ST398 (t899, t108-25%), ST1 (t127-5%) and ST5 (t688-2.5%). All isolates harboured the SCCmec type V (92.5%) or IVa (25%). In one isolate (2.5%), ST398/t899, the SCCmec resulted not detected. Three isolates (7.5%) carried one or more enterotoxin encoding genes (one strain had seg, sei, sem, sen and seo genes; two strains had seh gene). The 50% of isolated strains harboured PVL-encoding genes. Molecular analysis for icaA and icaD genes showed: 72.5% icaA and icaD positive, 25% only icaD gene and one icaA and icaD negative. The detection of MRSA in food of animal origin is a potential health hazard, thus it is necessary monitoring of food-producing animals and improving hygiene standards in food practices in order to reduce the microbiological risk to minimum.
23 October 2021 in Science of The Total Environment
• SARS-CoV-2 concentration in outdoor air was measured in north and south Italy. • Size distributions of virus-laden aerosol were investigated at both sites. • SARS-CoV-2 concentrations were <0.8 copies m−3 for each size range. • Outdoor airborne transmission does not explain differences in COVID-19 outbreaks. • Outdoor air was not infectious and safe for the public excluding crowded sites.
10 December 2016 in Food and Environmental Virology
Shellfish are an important vehicle for transmission of food-borne pathogens including norovirus (NoV) and hepatitis A virus (HAV). The risks related with consumption of shellfish are greater if these products are eaten raw or slightly cooked. As molluscs are filter-feeding organisms, they are able to concentrate pathogens dispersed in the water. Data on shellfish viral contamination are therefore useful to obtain a background information on the presence of contamination in the environment, chiefly in shellfish production areas and to generate a picture of the epidemiology of viral pathogens in local populations. From January 2013 to July 2015, 253 samples of bivalve molluscs collected in harvesting areas from a large coastal tract (860 km) of Southern Italy were screened for HAV and NoV of genogroups GI and GII, using real-time reverse transcription qualitative PCR. The RNA of HAV was not detected in any of the analyzed samples. In contrast, the RNA of NoV was identified in 14.2% of the samples with a higher prevalence of NoVs of genogroup GII (12.2%) than genogroup GI (1.6%). Upon sequence analysis of a short diagnostic region located in capsid region, the NoV strains were characterized as GII.2, GII.4 Sydney 2012, GII.6, GII.13, GI.4, and GI.6, all which were circulating in local populations in the same time span. These data confirm that consumption of mussels can expose consumers to relevant risks of infection. Also, matching between the NoV genotypes circulating in local population and detected in molluscs confirms the diffusion in the environment of NoVs.
15 February 2022 in International Journal of Food Microbiology
Coxiella burnetii is a Gram-negative obligate intracellular bacterium that is responsible for Q fever, a common zoonosis which is present virtually worldwide. This microorganism infects a wide range of wild and domestic mammals, but the main reservoirs are cattle, goats and sheep, which also represent sources of human infection. A potential route of transmission of this pathogen to humans is the consumption of C. burnetii-contaminated raw milk or dairy products derived from contaminated raw milk, although the role of these foods as possible infection sources is controversial. The aims of this study were (i) to apply two ddPCR based assays targeting the C. burnetii IS1111 and icd genes for the detection and quantification of C. burnetii DNA, and (ii) to evaluate the occurrence of C. burnetii DNA in raw milk and raw milk products from sheep and goats in Apulia and Basilicata regions of Southern Italy. Of 413 milk and cheese samples tested, 78 were positive for the presence of C. burnetii DNA (18.9%), specifically, 68 of 285 milk samples (23.9%) and 10 of 128 cheese samples (7.8%) The presence of both IS1111 and icd genes was detected in only 2 (2.6%) of the 78 positive samples, while the remaining 76 (97.4%) were positive only for IS1111. C. burnetii DNA was specifically detected by the ddPCR method, whereas no cross-amplification was observed with the DNA of other foodborne bacterial pathogens. The sensitivity of the ddPCR method was determined as 0.35 and 0.56 copies/μL for IS1111 and icd genes, respectively. The findings of this study demonstrate the presence of C. burnetii DNA in a significant proportion of raw milk and dairy products. Although there is no conclusive epidemiological evidence that C. burnetii infection occurs via food, the presence of this organism in raw milk and dairy products made of raw milk should be considered a potential hazard. ddPCR is a useful tool to investigate the quality and safety of food products due to its sensitivity and precision, and could be applied to routine testing.
1 October 2021 in Environmental Science and Pollution Research