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Non-typhoidal Salmonella enterica infection is a significant public health problem worldwide. The aim of this study was to characterize Salmonella enterica strains isolated from human specimens in central and southern Italy, for epidemiological studies. One hundred and fifty S. enterica strains were serotyped. Isolates were tested for their antimicrobial susceptibility, by disk diffusion method. The molecular characterizations, based on PCR, were carried out for the detection of invA gene and other virulence elements and phage marker genes. Eighteen different Salmonella serotypes were identified. The most common serotypes detected were S. Typhimurium, S. Enteritidis, the monophasic variant of S. Typhimurium (S. 4,[5],12:i:-), and S. Napoli. High resistance rates were recorded for tetracycline (64%), streptomycin (62%), sulphonamide (57%), and ampicillin (56%). The ASSuT R-type, also associated to resistance to other antibiotics, was highly prevalent in S. 4,[5],12:i:- (97%) and S. Typhimurium (55%), while the ACSSuT Rtype, also associated to other antibiotics, was observed prevalently in S. Typhimurium (20.4%). The genes of more common detection were invA (100%), sspH2 (86.6%), gtgB (84.6%), g8 (80%), sodC1 (77.3%), gipA (52.6%), sspH1 (52.6%).

In recent years, the incidence of foodborne diseases caused by Shiga toxin-producing Escherichia coli (STEC) has increased globally. For this reason, within the specific regional control plan for the detection of STEC in food products in Italy, the presence of STEC in unpasteurised milk cheeses was investigated. In total, 203 samples obtained from March 2011 to December 2013 were analysed, with two standard methods (ISO 16654:2001 and ISO 13136:2012). Two strains of E. coli O157 were isolated (2/161, 1.2%) but did not carry any virulence-associated genes and 22 stx-positive samples (22/146, 15.1%) were detected in enrichment cultures, mostly from ovine cheeses. Only two strains isolated from different ovine cheeses carried stx gene and none of these was eae-positive. This study confirms the presence of stx-positive E. coli and suggests that this type of food cannot be excluded as a potential vehicle of STEC.

In January 2013, 3 strains of Listeria monocytogenes isolated from one mother and her newborn and a second infant arrived at the Institute for Experimental Veterinary Medicine of Latium and Tuscany. At the same time the Local Health Unit Rome B sampled at retail a smoked salmon that was suspected to be involved in the transmission of the disease. The sample was tested for the presence of L. monocytogenes (UNI EN ISO 11290: 2005 part 1 and 2). Laboratory investigations have shown that all 3 strains isolated from patients belonged to serotype 4b of two different clusters (cluster B for the isolates from mother and child and cluster A to that obtained from another baby), so no epidemiological link was demonstrated in the human cases. The tests conducted on smoked salmon have shown the presence of L. monocytogenes serotype 1/2a. Therefore, no correlation has been demonstrated between the reported cases of listeriosis and the food analyzed.

Following a Listeria monocytogenes detection in a mozzarella cheese sampled at a dairy plant in Lazio Region, further investigations have been conducted both by the competent Authority and the food business operatordairy factory (as a part of dairy factory HACCP control). In total, 90 dairy products, 7 brine and 64 environmental samples have been tested. The prevalence of Listeria monocytogenes was 24.4% in mozzarella cheese, and 9.4% in environmental samples, while brines were all negatives. Forty-seven strains of L. monocytogenes have been isolated, all belonging to 4b/4e serotype. In 12 of these, the macrorestriction profile has been determined by means of pulsed field gel electrophoresis. The profiles obtained with AscI enzyme showed a 100% similarity while those obtained with ApaI a 96.78% similarity. These characteristics of the isolated strains jointly with the production process of mozzarella cheese has allowed to hypothesise an environmental contamination.

During the wild boars hunting season (2012-2013), 6508 adults were shot in Lazio Region, Viterbo territory. Out of the 6508, 393 subjects were sampled to be tested for the detection of Salmonella spp., Yersinia enterocolitica, E. coli VTEC and Trichinella spp. For this purpose, diaphragm and skeletal muscles samples were collected after the shooting, and tested at the Istituto Zooprofilattico Sperimentale Lazio and Toscana laboratories, Rome, Italy. Samples were tested respectively by polymerase chain reaction, enzyme linked immunofluorescent assay, microbiological and parasitological assays. The positivity percentages are 3.6% for Salmonella spp., 14.8% (out of 230 samples tested) for Yersinia enterocolitica, 4.6% for E.coli VTEC (vtx 1 and 2 genes). Each positive sample for vtx 1 and 2 was tested to isolate Verotoxigenic E.coli strains; none of them was positive for the same virulence genes. All diaphragm samples were negative to the trichinoscopic test. Every bacterial strain was identified serologically by seroagglutination test.