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We investigated the virulence properties of four Vibrio parahaemolyticus strains causing acute gastroenteritis following consumption of indigenous mussels in Italy. The isolated strains were cytotoxic and adhesive but, surprisingly, lacked tdh, trh, and type three secretion system 2 (T3SS2) genes. We emphasize that nontoxigenic V. parahaemolyticus can induce acute gastroenteritis, highlighting the need for more investigation of the pathogenicity of this microorganism. Vibrio parahaemolyticus infections cause acute, self-limiting gastroenteritis, typically characterized by diarrhea, abdominal cramps, nausea, vomiting, fever, and chills, lasting 1 to 3 days. The onset usually occurs within 24 h of eating contaminated food. Cases are most commonly reported during the warmer months and are often associated with eating raw or undercooked shellfish or other cooked foods that have been cross-contaminated with raw shellfish (22). Pathogenicity of this microorganism is attributed to the production of a thermostable direct hemolysin (TDH) and the TDH-related hemolysin (TRH) (13). Recently, type three secretion system 2 (T3SS2) of V. parahaemolyticus has been investigated as an additional potential indicator of strain virulence (2,8,17). Together, the tdh, trh, and T3SS2 genes are widely considered the predominant indicators of strain virulence for this microorganism (8). This is substantiated by the prevalence of these genetic markers in clinical V. parahaemolyticus isolates, as opposed to their infrequent detection in food and environmental samples (8).For this report, we characterized four V. parahaemolyticus strains lacking tdh, trh, and T3SS2 genes isolated as the sole pathogen from patients affected by acute gastroenteritis with indigenous mussels as the most probable source of infection. On 20 September 2010 in Torino (northern Italy), 4 people were hospitalized with acute gastroenteritis. The first case involved a healthy 47-year-old man (patient A), while a family group outbreak involved another three healthy individuals: a 55-year-old woman (patient B), a 59-year-old man (patient C), and a 58-year-old man (patient D). Epidemiological information reported that none of the patients had recently traveled to other countries and that on 19 September they had eaten home-cooked mussels, probably undercooked. Mussels involved in both the sporadic case and the outbreak came from the same Italian growing area (North Adriatic), but it was not possible to trace the specific lots. Patient A and patients B, C, and D developed diarrhea, fever, abdominal cramps, nausea, and vomiting about 13 h and about 18 h after mussel consumption, respectively. On admission, the patients were treated with intravenous hydration, and the symptoms ceased within 48 h without the need for antibiotic therapy.Stool specimens of patients were cultured on MacConkey agar, Salmonella-Shigella agar, Columbia blood agar, Hektoen agar, 5% sheep blood agar supplemented with ampicillin (30 g/ml) (ASBA 30), Yersinia cefsulodin-irgasan-novobiocin (CIN) agar (a...

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Summary The relationship between Vibrio parahaemolyticus strains isolated from the aquatic environment and those isolated from cases of infection in humans is poorly understood due to the low prevalence of tdh‐ and/or trh‐positive strains in the environment. To address this concern, it would be useful to analyse the genetic relationships among environmental and food strains and with reference to clinical isolates, also applying molecular typing methods. The aim of this study was to evaluate the prevalence of toxigenic V. parahaemolyticus in Italian coastal waters and seafood, to examine intra‐species variability and to identify, using serotyping and pulsed‐field gel electrophoresis (PFGE), relationships among strains from different sources, geographical origin and period of isolation. Of the 192 V. parahaemolyticus strains isolated in different Italian areas and examined in this study, 25 (13.0%) proved to carry the trh gene while none of the strains proved positive to the search by PCR for tdh and Group‐Specific‐toxRS genes. The prevalence of toxigenic strains in the Tyrrhenian Sea was significantly lower than that calculated for the Ligurian coasts. Regarding the sources of isolation, the higher prevalence of trh‐positive V. parahaemolyticus was revealed in fish, followed by clams, plankton, oysters, mussels and lastly seawater. Within the toxigenic strains, 16 serotypes and 20 distinct PFGE patterns were identified. Two clusters, which included a total of 8 V. parahaemolyticus strains, were specifically associated with the North Adriatic Sea area and were stable over time. Our results demonstrate that trh‐positive V. parahaemolyticus strains circulated in Italy in the period 2002–2009 with a prevalence higher than that reported from other European and extra‐European countries, confirming that toxigenic V. parahaemolyticus is an emerging public health concern in Italy, regardless of its pandemic potential.

Dogs are a common feeding hosts for Ixodes ricinus and may act as reservoir hosts for zoonotic tick-borne pathogens (TBPs) and as carriers of infected ticks into human settings. The aim of this work was to evaluate the presence of several selected TBPs of significant public health concern by molecular methods in I. ricinus recovered from dogs living in urban and suburban settings in central Italy. A total of 212 I. ricinus specimens were collected from the coat of domestic dogs. DNA was extracted from each specimen individually and tested for Rickettsia spp., Borrelia burgdorferi sensu lato, Babesia spp., and Anaplasma phagocytophilum, using real-time and conventional PCR protocols, followed by sequencing. Sixty-one ticks (28.8%) tested positive for TBPs; 57 samples were infected by one pathogen, while four showed coinfections. Rickettsia spp. was detected in 39 specimens (18.4%), of which 32 were identified as Rickettsia monacensis and seven as Rickettsia helvetica. Twenty-two samples (10.4%) tested positive for A. phagocytophilum; Borrelia lusitaniae and Borrelia afzelii were detected in two specimens and one specimen, respectively. One tick (0.5%) was found to be positive for Babesia venatorum (EU1). Our findings reveal the significant exposure of dogs to TBPs of public health concern and provide data on the role of dogs in the circulation of I. ricinus-borne pathogens in central Italy.

The aims of this study were to investigate the prevalence of total and pathogenic Vibrio parahaemolyticus strains in Italian mussels from different geographical areas of the Adriatic Sea and to determine their serotypes, toxigenic profiles and pandemic potential. Out of 559 samples analysed during 2007, 65 (11.6%) were positive for V. parahaemolyticus. None of the isolates had the genes for thermostable direct haemolysin (tdh) and pandemic marker (toxRS), while five strains (7.7%) had that for TDH-related haemolysin (trh). Regarding geographical location of the toxigenic strains, three were from the Adriatic coast of Puglia, one from Veneto, and one from the Marches. The trh-positive V. parahaemolyticus isolates from Puglia belonged to O1:KUT (2/3) and O1:K37(1/3) serotypes, the trh-positive isolate from the Marches to OUT(O untypeable):KUT serotype, and that from Veneto to O3:KUT. The prevalence of trh-positive V. parahaemolyticus obtained from mussels in this study was higher respect to that reported in previous studies from other European and Extraeuropean countries. The Health Authorities should be more aware of the epidemiological role of environmental V. parahaemolyticus in local food-borne diseases, and increase the microbial surveillance on these microorganisms isolated from shellfish.