The present survey collected and analyzed the results of routine testing for Salmonella enterica and Listeria monocytogenes on foods of animal origin submitted for official controls in Italy during 2001 to 2002. Salmonella was detected in 2.2% of 71,643 food samples examined, and the isolation rates ranged from 9.9% for raw poultry meat to less than 0.1% for dairy products. Isolation rates were also high in raw pork (4.9%) and processed meats (5.3%), which often involved pork. Low rates were observed in seafood (0.5%) and in ready-to-eat foods, such as grocery products (0.7%) and ice creams (0.1%). Serotyping showed that approximately 50% of the isolates belonged to the serotypes most commonly isolated from humans in Italy, thus confirming that most cases of human salmonellosis have a foodborne origin. Levels of L. monocytogenes were higher than what is accepted by the current regulation in 2.4% of 42,300 food samples. The positivity rates ranged from 10.3% in raw pork to none in eggs and egg products. Contamination rates were higher in other meat products (between 2 and 5%) and fish (6.5%) than in cheeses (1.1%) and other dairy products (0.6%). Routine control activities on the microbial contamination of foods can generate data with statistical and epidemiological value. Such data can be used as a basis for estimating the exposure of consumers to foodborne pathogens, following the trends of contamination over time, and evaluating the effects of control measures on the contamination of food.

Aims:  To ascertain whether in Brucella abortus‐infected water buffalo herds, the number of newly infected animals could be reduced by culling superspreaders (the animals secreting ≥104 CFU per ml of milk). Methods and Results:  The number of B. abortus present in the milk (CFU per ml) from 500 water buffaloes was measured by the culture. Each animal was tested three times, at one month intervals. The presence or the absence of B. abortus in each milk sample was confirmed by PCR. A majority of infected animals shed the pathogen at a low level (≤103 CFU ml−1). However, a few infected individuals (superspreaders) shed large numbers of B. abortus (≥104 CFU ml−1). Quantitative PCR of B. abortus positive milk samples gave comparable results to culture. Culling of the superspreaders was sufficient to arrest the spread of infection. Significance and Impact of the Study:  The approach described here can reduce significantly the cost of controlling brucellosis. Culture and quantitative PCR tests identify superspreaders and, compared with the serological tests in use to detect brucellosis, provide also a more accurate estimate of the disease incidence.

A case-control study established that the haplotype pair HYA/HYA at the MBL (mannose binding lectin) locus of water buffalo is associated with resistance to Brucella abortus infection (P < 10(-7)) and the haplotype pairs LYD/LYD with susceptibility to the same pathogen (P < 10(-7)). The subjects included in the present study were tested twice-at a 1-month interval-for the presence of anti-B. abortus antibodies in the serum by agglutination, complement fixation and flow cytometry. Cases (335 subjects) included animals consistently positive to all these tests; controls (335 subjects) comprised animals exposed yet negative by the same tests. The serum from genetically resistant subjects displayed in vitro significantly higher antibacterial activity compared to the serum from genetically susceptible subjects, lending biological significance to the results from the association study. Inhibition of the antibacterial activity following heat treatment of the serum, addition of specific MBL inhibitors (EDTA, mannose, N-acetyl-D: -glucosamine) or anti-human MBL antiserum provide convincing evidence that the antibacterial activity present in the serum results from the interaction between MBL and B. abortus. A replication study (comprising 100 cases and 100 controls) confirmed the results from the original study.

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The 3' untranslated region of the water buffalo Nramp1 (natural resistance-associated macrophage protein 1) gene contains two alleles (Nramp1A and Nramp1B), as detected by the denaturing gradient gel electrophoresis (DGGE) technique. The Nramp1BB genotype is associated with resistance of water buffalo to the intracellular pathogen Brucella abortus. This article provides evidence that the Nramp1AA genotype is associated with susceptibility to the same pathogen. Susceptibility or resistance of water buffalo to B. abortus was established by agglutination, complement fixation, and skin tests. The Nramp1 genotype was established by DGGE analysis. The association between the Nramp1AA genotype and susceptibility to B. abortus was demonstrated in two independent population samples (152 cases and 281 controls; 87 cases and 124 controls, respectively). Macrophages from Nramp1AA subjects displayed a lower Nramp1 mRNA level when compared with macrophages from Nramp1BB subjects. Also, monocytes and macrophages from Nramp1AA subjects displayed a higher number of viable intracellular bacteria in comparison with monocytes and macrophages from Nramp1BB animals, providing biological significance to the results from association studies.

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