Enterotoxin genes, enterotoxin production, and methicillin resistance in Staphylococcus aureus isolated from milk and dairy products in Central Italy

AbstractA total of 227 Staphylococcus aureus colonies, isolated from 54 samples of raw milk and dairy products of bovine, ovine, caprine and bubaline origin were tested for the presence of genes coding for staphylococcal enterotoxins (SEs/SEls) and for methicillin resistance. Ninety-three colonies, from 31 of the 54 samples (57.4%) and from 18 (69.2%) of the 26 farms of origin tested positive for SEs/SEls genes. Most isolates harboured more than one toxin gene and 15 different toxinotypes were recorded. The most frequent were “sec” gene alone (28.6%), “sea, sed, ser, selj” (20%), “seg, sei” and “seh” (8.6%). The 77 colonies harbouring “classical enterotoxins” genes (sea-sed) were further tested for enterotoxin production, which was assessed for 59.2% of the colonies. Three methicillin-resistant S. aureus (MRSA) isolates were detected in three different ovine milk/dairy product samples (1.3%). All isolates belonged to spa type t127, sequence type 1, clonal complex 1, SCCmec type IVa

Uno sguardo d’assieme, tra teoria e tecnica

Il capitolo individua l’e-learning come un campo di azione e di indagine in cui sono indissolubilmente intrecciati la tecnologia e il pensiero, i modi della pratica e quelli della riflessione. La rete è interpretata come ambiente per l’apprendimento, che sollecita e favorisce una nuova descrizione del concetto di sapere, fondata sui concetti di apertura, ridefinizione dinamica della conoscenza e attitudine alla ricerca. Le nuove chiavi interpretative del vero e-learning rimandano alla metafora di intelligenza collettiva, proposto da Lévy, e al concetto di intentional learning, proposto nell’ambito del progetto CSILE. Nei percorsi di formazione del vero e-learning il testo e il tempo si modificano progressivamente: il testo digitale è un ipertesto che favorisce la condivisione del lavoro e l’apertura alla rete; il tempo diviene un eterno presente, che amplia significativamente le possibilità di apprendimento. La progettazione didattica orientata al paradigma del costruttivismo sociale allontana il rischio, assai diffuso, di ricadere in una riedizione potenziata della istruzione programmata di skinneriana memoria: in effetti, se la didattica in rete non è costruttivista, vengono amplificati proprio gli elementi di maggiore debolezza della tradizionale didattica trasmissiva, caratterizzata da una sostanziale unidirezionalità della comunicazione

Control of bovine sub-clinical mastitis by using herbal extract during lactation

Objective of the study was to evaluate the effects of feeding administration of herbal extracts for the control of bovine subclinical mastitis during lactation. A total of 36 Italian Friesian lactating cows with subclinical mastitis were randomly divided into three homogeneous groups: phyto-treated group, placebo-treated group, and control group. In phyto-treated group, cows received 5 gr. of standardised fluid extract of Spirea ulmaria L. and 6 gr. of standardised extract of Astragalus membranaceus BUNGE, administered orally as complex once daily for 15 days. Milk samples were collected from the mammary quarters before the beginning of the experiment, and then 14, 28 and 56 days after for analysis of bacteria, and somatic cells count (SCC). Milk flow and production were also recorded. The treatment positively influenced the health status of mammary glands, resulting particularly effective against Coagulase Negative Staphilococci. A reduction of infected quarters was highlighted in treated group ( 16.7% vs 30.2% and 37.5%, respectively in control and placebo groups; P<0.05). Further studies are needed to ascertain some aspects of herbal extracts action in ruminants and their effectiveness in different experimental and practical conditions

ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS IN SHEEP RAW MILK

A total of 366 raw milk samples from 30 sheep farms were examined quantitatively for Staphylococcus aureus. Enterotoxin production by strains of Staphylococcus aureus isolated was investigated. S. aureus was detected in 19 farms (63,3%). The ability to synthetise enterotoxins was found in ten strains (52,6%). Production of staphylococcal enterotoxins C (SEC) was recorded in 6 (60%) and production of SEC together with staphylococcal enterotoxin A (SEA) in 4 (40%) staphylococcal isolates. Raw milk products are vulnerable to contamination by S. aureus. Strategies to reduce the occurrence of S. aureus in bulk milk are of particular importance on farms where milk is used for raw milk products

Paediatric HUS Cases Related to the Consumption of Raw Milk Sold by Vending Machines in Italy: Quantitative Risk Assessment Based on Escherichia coli O157 Official Controls over 7 years

A quantitative risk assessment (RA) was developed to estimate haemolytic-uremic syndrome (HUS) cases in paediatric population associated with the consumption of raw milk sold in vending machines in Italy. The historical national evolution of raw milk consumption phenomenon since 2008, when consumer interest started to grow, and after 7\uc2&nbsp;years of marketing adjustment, is outlined. Exposure assessment was based on the official Shiga toxin-producing Escherichia coli O157:H7 (STEC) microbiological records of raw milk samples from vending machines monitored by the regional Veterinary Authorities from 2008 to 2014, microbial growth during storage, consumption frequency of raw milk, serving size, consumption preference and age of consumers. The differential risk considered milk handled under regulation conditions (4\uc2\ub0C throughout all phases) and the worst time\ue2\u80\u93temperature field handling conditions detected. In case of boiling milk before consumption, we assumed that the risk of HUS is fixed at zero. The model estimates clearly show that the public health significance of HUS cases due to raw milk STEC contamination depends on the current variability surrounding the risk profile of the food and the consumer behaviour has more impact than milk storage scenario. The estimated HUS cases predicted by our model are roughly in line with the effective STEC O157-associated HUS cases notified in Italy only when the proportion of consumers not boiling milk before consumption is assumed to be 1%. Raw milk consumption remains a source of E.\uc2&nbsp;coli O157:H7 for humans, but its overall relevance is likely to have subsided and significant caution should be exerted for temporal, geographical and consumers behaviour analysis. Health education programmes and regulatory actions are required to educate people, primarily children, on other STEC sources

Quantitative Risk Assessment of Human Salmonellosis and Listeriosis Related to the Consumption of Raw Milk in Italy

Two quantitative risk assessment (RA) models were developed to describe the risk of salmonellosis and listeriosis linked to consumption of raw milk sold in vending machines in Italy. Exposure assessment considered the official microbiological records monitoring raw milk samples from vending machines performed by the regional Veterinary Authorities from 2008 to 2011, microbial growth during storage, destruction experiments, consumption frequency of raw milk, serving size, and consumption preference. Two separate RA models were developed, one for the consumption of boiled milk and the other for the consumption of raw milk. The RA models predicted no human listeriosis cases per year either in the best or worst storage conditions and with or without boiling raw milk, whereas the annual estimated cases of salmonellosis depend on the D-R relationships used in the model, the milk storage conditions and consumer behavior in relation to boiling raw milk or not. For example, the estimated salmonellosis cases ranged from no expected cases, assuming that the entire population boiled milk before consumption, to a maximum of 980,128 cases, assuming that the entire population drank raw milk without boiling, in the worst milk storage conditions and with the lowest D-R model. The findings of this study clearly show how consumer behavior could affect the probability and number of salmonellosis cases, and in general the risk of illness. Hence the proposed RA models emphasize yet again that boiling milk before drinking is a simple yet effective tool to protect consumers against the risk of illness inherent in the consumption of raw milk. The models may also offer risk managers a useful tool to identify or implement appropriate measures to control the risk of acquiring foodborne pathogens. Quantification of the risks associated with raw milk consumption is necessary from a public health perspectiv

Four year monitoring of foodborne pathogens in raw milk sold by vending machines in Italy.

Prevalence data were collected from official microbiological records monitoring four selected foodborne pathogens (Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni) in raw milk sold by self-service vending machines in seven Italian Regions (n. 60907 samples from 1239 vending machines) during the years 2008 to 2011. Data of samples analyzed both by culture-based and real-time PCR methods were collected in one Region. A total of 100 raw milk consumers in four regions were interviewed while purchasing raw milk from vending machines. One hundred and seventy eight samples out of 60907 were positive for one of the four foodborne pathogens investigated; overall, 18 samples were positive for Salmonella spp., 83 for L. monocytogenes, 24 for E. coli O157:H7 and 53 for C. jejuni in the seven Regions investigated. There were no significant differences in prevalence among Regions, but a significant increase in C. jejuni prevalence was observed over the years. A comparison of the two different analysis methods showed that real-time PCR is from 2.71 to 9.40 times more sensitive than culture-based method. Data on consumer habits showed that some behaviors may enhance the risk of infection due to raw milk consumption: 37% of consumers do not boil milk before consumption, 93% never use an insulated bag to transport raw milk home, and raw milk is consumed by children under five years of age. The study emphasizes that end-product controls alone are not sufficient to guarantee an adequate level of consumer protection. The beta distribution of positive samples in this study and the data on raw milk consumer habits are useful and appropriate for the development of a National Quantitative Risk Assessment of Salmonella spp., L. monocytogenes, E. coli O157 and C. jejuni related to raw milk consumption

Paediatric HUS Cases Related to the Consumption of Raw Milk Sold by Vending Machines in Italy: Quantitative Risk Assessment Based on Escherichia coli

A quantitative risk assessment (RA) was developed to estimate haemolytic-uremic syndrome (HUS) cases in paediatric population associated with the consumption of raw milk sold in vending machines in Italy. The historical national evolution of raw milk consumption phenomenon since 2008, when consumer interest started to grow, and after 7Â&nbsp;years of marketing adjustment, is outlined. Exposure assessment was based on the official Shiga toxin-producing Escherichia coli O157:H7 (STEC) microbiological records of raw milk samples from vending machines monitored by the regional Veterinary Authorities from 2008 to 2014, microbial growth during storage, consumption frequency of raw milk, serving size, consumption preference and age of consumers. The differential risk considered milk handled under regulation conditions (4°C throughout all phases) and the worst timeâtemperature field handling conditions detected. In case of boiling milk before consumption, we assumed that the risk of HUS is fixed at zero. The model estimates clearly show that the public health significance of HUS cases due to raw milk STEC contamination depends on the current variability surrounding the risk profile of the food and the consumer behaviour has more impact than milk storage scenario. The estimated HUS cases predicted by our model are roughly in line with the effective STEC O157-associated HUS cases notified in Italy only when the proportion of consumers not boiling milk before consumption is assumed to be 1%. Raw milk consumption remains a source of E.Â&nbsp;coli O157:H7 for humans, but its overall relevance is likely to have subsided and significant caution should be exerted for temporal, geographical and consumers behaviour analysis. Health education programmes and regulatory actions are required to educate people, primarily children, on other STEC sources