Search

Consumption of raw food, especially smoked fish, meat, soft cheeses, and vegetables, contaminated with Listeria monocytogenes can cause listeriosis, which can be invasive in pregnant women, elderly...

Usutu virus (USUV), a member of the genus Flavivirus, is known to circulate at low prevalence in Northern Italy, and has been reported to cause overt infection. USUV was first reported in Europe in 2001, but a retrospective study showed that it has been present in Italy at least since 1996. Seroprevalence data for USUV antibodies in sera are being collected in different European countries, showing circulation at low prevalence in human populations. Interestingly, two consecutive studies in Northern Italy indicate a possible increase in the presence of the virus, from 0% to 0.23% seroprevalence in blood donors. In this study, antibodies against USUV were measured in 3 consecutive blood samples collected from October 2014 to December 2015 from 33 forestry workers in the Po river valley, while samples from 200 blood donors from the same geographical area were tested in parallel. Neutralizing and IgG antibodies were found in six forestry workers (18.1%) and in two blood donors (1%). Our results indicate that USUV circulation in the examined area, part of a highly populated region in Northern Italy, is higher than expected. Healthy subjects exhibit a higher prevalence than what was found in a previous report in an adjoining region (0.23%), while the population at risk shows a much higher prevalence value (18.1%).

Salmonella enterica serovar Typhimurium (STm) and its monophasic variant 4,[5],12:i:- (VMSTm) have been responsible for an increased number of foodborne infections in humans in Europe in recent years. The aim of this study was to investigate the origin of three foodborne salmonellosis outbreaks that occurred in Pavia Province (Lombardy region, northern Italy) in 2010. Phenotypic and genetic characteristics of the STm and VMSTm isolates from patients and from food that were recovered in the framework of the three outbreaks were evaluated through serotyping, phage typing, antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), and multiple-locus variable-number tandem repeat analysis (MLVA). Salami from three artisan producers, which had all purchased meat from the same slaughterhouse, was the food source of infection in outbreak I. STm isolates were recovered from salami and patients with symptoms of gastroenteritis. These isolates had the same PFGE type and the same rare MLVA profile (3-18-9-NA-211). The same molecular profiles were found in an STm isolate from a salami, which likely was the source of another family outbreak (II). A VMSTm strain with common phenotypic and molecular profiles was isolated from three hospitalized patients and identified as the cause of another putative outbreak (III). During the following 3 years (2011 through 2013), 360 salami produced in Pavia Province were monitored for the presence of S. enterica . In 2011, no STm and VMSTm isolates were recovered from 159 salami tested. During 2012 and 2013, 13.9% of 201 tested salami harbored S. enterica , and half of the isolates were VMSTm, mainly in salami from those artisan producers involved in the previous outbreaks. These isolates were genetically variable, especially in terms of MLVA profiles. The data collected suggest that from 2012, VMSTm has replaced STm in the environments of the salami producers monitored in this study, and these data confirm the dominance of this emergent serovar along the pork supply chain.

Background Two main genetic groups (B.12 and B.FTNF002-00) of Francisella tularensis ssp. holarctica are endemic in Europe. The B.FTNF002-00 group proved to be dominant in Western European countries, while strains of the B.12 group were isolated mainly in Northern, Central and Eastern Europe. The clinical course of tularemia in the European brown hare (Lepus europaeus) also shows distinct patterns according to the geographical area. Acute course of the disease is observed in hares in Western European countries, while signs of sub-acute or chronic infection are more frequently detected in the eastern part of the continent. The aim of the present study was to examine whether there is any difference in the virulence of the strains belonging to the B.FTNF002-00 and B.12 genetic clades. Results Experimental infection of Fischer 344 rats was performed by intra-peritoneal injection of three dilutions of a Hungarian (B.12 genotype) and an Italian (B.FTNF002-00 genotype) F. tularensis ssp. holarctica strain. Moderate difference was observed in the virulence of the two genotypes. Significant differences were observed in total weight loss values and scores of clinical signs between the two genotypes with more rats succumbing to tularemia in groups infected with the B.FTNF002-00 genotype. Conclusions Results of the experimental infection are consistent with previous clinical observations and pathological studies suggesting that F. tularensis ssp. holarctica genotype B.FTNF002-00 has higher pathogenic potential than the B.12 genotype. Electronic supplementary material The online version of this article (doi:10.1186/s12917-017-0968-9) contains supplementary material, which is available to authorized users.

Midichloria mitochondrii is an intracellular bacterium found in the hard tick Ixodes ricinus. In this arthropod, M. mitochondrii is observed in the oocytes and in other cells of the ovary, where the symbiont is present in the cell cytoplasm and inside the mitochondria. No studies have so far investigated whether M. mitochondrii is present in the salivary glands of the tick and whether it is transmitted to vertebrates during the tick blood meal. To address the above issues, we developed a recombinant antigen of M. mitochondrii (to screen human sera) and antibodies against this antigen (for the staining of the symbiont). Using these reagents we show that (i) M. mitochondrii is present in the salivary glands of I. ricinus and that (ii) seropositivity against M. mitochondrii is highly prevalent in humans parasitized by I. ricinus (58%), while it is very low in healthy individuals (1·2%). These results provide evidence that M. mitochondrii is released with the tick saliva and raise the possibility that M. mitochondrii is infectious to vertebrates. Besides this, our study indicates that M. mitochondrii should be regarded as a package of antigens inoculated into the human host during the tick bite. This implies that the immunology of the response toward the saliva of I. ricinus is to be reconsidered on the basis of potential effects of M. mitochondrii and poses the basis for the development of novel markers for investigating the exposure of humans and animals to this tick species.

Twelve Large White pigs were experimentally infected with 1000 Toxoplasma gondii oocysts/each. Serology was carried out at different time points post infection (p.i.) and animals were slaughtered at four months p.i. One of two thighs was examined for T. gondii infection status by PCR and bioassay in mice. The other thigh was processed for Parma ham production. Four thighs were examined after twelve months of curing, four after fourteen months and four were examined after sixteen months. Cured hams were analyzed by PCR, bioassay and in-vitro cultivation on Vero cells followed by real-time PCR. Pigs seroconverted from day 21 p.i. Bioassays were positive for all fresh thighs, but negative for cured hams. PCR was positive for parasite DNA from most thighs both at slaughter and post curing, but parasite growth was not observed following in vitro cultivation and real-time PCR. Results indicate that the curing process of Parma Ham (PDO), when carried out according to the Parma Ham consortium regulations, can inactivate T. gondii tissue cysts. Results would suggest that food-borne transmission of T. gondii to consumers from Parma ham can be excluded.

Recently, Italy-particularly the Emilia-Romagna region-was the location of consecutive outbreaks of human diseases caused by the arboviruses chikungunya virus and West Nile virus. The two outbreaks, spread by different species of mosquitoes, were not related, but pointed out the lack of an arboviral surveillance program in this region. Beginning in 2007 entomological surveillance was initiated in the Emilia-Romagna region, and in 2008 the program was improved and extended at Lombardia region. Using CO(2)-baited traps, 65,292 mosquitoes were collected; pooled by date of collection, location, and species; macerated manually; and tested by reverse transcription (RT)-polymerase chain reaction for the presence of alphaviruses, orthobunyaviruses, and flaviviruses. Amplicons were sequenced and employed for identification of viral RNA by basic local alignment search tool search in GenBank. Results of these assays showed (1) the presence of West Nile virus in two pools of Culex pipiens mosquitoes, (2) the presence of RNA of two orthobunyaviruses, Tahyna virus in a pool of Ochlerotatus caspius mosquitoes and Batai virus in a pool of Anopheles maculipennis mosquitoes, and (3) the presence of flavivirus RNAs in pools of Oc. caspius, Aedes albopictus, and Aedes vexans mosquitoes; the sequences of these amplicons were most closely related to flaviviruses that have been detected only in mosquitoes and had no recognized vertebrate host (Aedes flavivirus, Culex flavivirus, and Kamiti River virus).

Bartonella henselae is a fastidious bacterium associated with infections in humans and cats. The mechanisms involved in the long-term survival of bartonellae despite vigorous host immune responses are poorly understood. Generation of genetic variants is a possible strategy to circumvent the host specific immune responses. The authors have recently demonstrated the coexistence of different genetic variants within the progeny of three primary B. henselae isolates from Berlin by PFGE analysis. Aims of the present study were to determine whether coexistence of different variants is a common feature of B. henselae isolates worldwide and whether the genetic variants originally emerged in vivo. Thirty-four primary isolates from different geographical regions were analysed by subjecting multiple single-colony-derived cultures to PFGE analysis. Up to three genetic variants were detected within 20 (58.8 %) isolates, indicating that most primary isolates display a mosaic-like structure. The close relatedness of the genetic variants within an isolate was confirmed by multi-locus sequence typing. In contrast to the primary isolates, no genetic variants were detected within the progeny of 20 experimental clones generated in vitro from 20 primary isolates, suggesting that the variants were not induced in vitro during the procedure of PFGE analysis. Hence, the genetic variants within a primary isolate most likely originally emerged in vivo. Consideration of the mosaic structure of primary isolates is essential when interpreting typing studies on B. henselae.

BackgroundTularemia is a zoonosis caused by the Francisella tularensis, a highly infectious Gram-negative coccobacillus. Due to easy dissemination, multiple routes of infection, high environmental contamination and morbidity and mortality rates, Francisella is considered a potential bioterrorism threat and classified as a category A select agent by the CDC. Tick bites are among the most prevalent modes of transmission, and ticks have been indicated as a possible reservoir, although their reservoir competence has yet to be defined. Tick-borne transmission of F. tularensis was recognized in 1923, and transstadial transmission has been demonstrated in several tick species. Studies on transovarial transmission, however, have reported conflicting results.ObjectiveThe aim of this study was to evaluate the role of ticks as reservoirs for Francisella, assessing the transovarial transmission of F. tularensis subsp. holarctica in ticks, using experimentally-infected females of Dermacentor reticulatus and Ixodes ricinus.ResultsTransmission electron microscopy and fluorescence in situ hybridization showed F. tularensis within oocytes. However, cultures and bioassays of eggs and larvae were negative; in addition, microscopy techniques revealed bacterial degeneration/death in the oocytes.ConclusionsThese results suggest that bacterial death might occur in oocytes, preventing the transovarial transmission of Francisella. We can speculate that Francisella does not have a defined reservoir, but that rather various biological niches (e.g. ticks, rodents), that allow the bacterium to persist in the environment. Our results, suggesting that ticks are not competent for the bacterium vertical transmission, are congruent with this view.

Coxiella burnetii , the aetiologic agent of Q fever (Query fever), is an intracellular Gram-negative bacterium belonging to the family of Coxiellaceae (Drancourt and Raoult 2005). Infections by C burnetii involve a wide range of susceptible hosts, ranging from mammals to arthropods (Angelakis and Raoult 2010). Abortion, stillbirth and non-viable neonates are the main clinical signs of infection in sheep and goats, while metritis, infertility and, rarely abortion, are typical for cattle (Arricau-Bouvery and Rodolakis 2005). C burnetii can produce spore-like forms, which are easily spread by wind and are able to survive for several months in the environment; for this reason the inhalation of contaminated aerosol and/or dust is considered the primary route of infection (Arricau-Bouvery and Rodolakis 2005). The consumption of contaminated raw milk does not seem to represent an efficient route of disease transmission (Rodolakis and others 2007), however, bulk tank milk (BTM) is an important specimen for epidemiological survey on dairy herds. In fact, even if C burnetii can be excreted in milk by infected animals continuously or intermittently (Guatteo and others 2007), milk is the most frequent way of shedding in asymptomatic cows (Rodolakis and others 2007). Many investigations have been performed among ruminant farms in European countries (Paiba and others 1999, Agger and others 2010, McCaughey …

a b s t r a c t Background: Specific bacterial infections or alterations of the gut microbiota likely trigger immuno- pathological phenomena associated with Crohn's disease and ulcerative colitis. Mycobacterium avium subspecies paratuberculosis is a candidate etiological agent of Crohn's disease. Definitive causal connec- tion between Mycobacterium avium subspecies paratuberculosis infection and Crohn's disease has not been demonstrated. Aims: To determine the circulation of Mycobacterium avium subspecies paratuberculosis in Crohn's disease patients and water supplies in an Italian region where this bacterium is endemic in cattle farms. Methods: Mycobacterium avium subspecies paratuberculosis screening was performed on biopsies from human patients, and from water samples, using two different PCR procedures. Results: In hospitals where multiple specimens were obtained from different sites in the intestine, the prevalence of Mycobacterium avium subspecies paratuberculosis infection was 82.1% and 40% respec- tively in Crohn's disease and ulcerative colitis patients; in another hospital, where single specimens were obtained from patients, the bacterium was not detected. Control subjects also harboured Mycobac- terium avium subspecies paratuberculosis, but at a lower prevalence. Tap water samples collected in the study area contained Mycobacterium avium subspecies paratuberculosis DNA. Discussion: The results of screenings for Mycobacterium avium subspecies paratuberculosis in humans are deeply influenced by both the number and location of the collected biopsies. There is a wide circulation of the organism in the study area, considering the prevalence in humans and its presence in drinking water.

Bartonella henselae has been identified and characterized for the first time in Italy. A strain, designed Pavia-1, was isolated from the blood of a cat whose owner developed cat scratch disease (CSD). Pavia-1 and two American B. henselae strains (Houston-1, ATCC 49882, type I and strain 269608, UC Davis, type II) were compared by whole-cell fatty analysis (CFA), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for protein profiles, Western immunoblotting (WB) for reactivity with polyclonal antibodies, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), type-specific 16S rRNA PCRs, and pulsed-field gel electrophoresis (PFGE). Bartonella clarridgeiae (ATCC 51734) was also included for comparison. Pavia-1 was identified as a B. henselae type I. PFGE allowed differentiation between B. clarridgeiae and B. henselae and furthermore, between all the B. henselae strains. The fingerprints of PFGE observed for Pavia-1 were distinct from those of B. henselae type II and also of Houston-1, suggesting that the two type I strains derived from two different clones. These results show the capability of B. henselae to develop genotypic variability between genetically related strains.

A fatal pneumonia due to Legionella pneumophila was diagnosed in a young calf reared in a dairy herd located in northern Italy. Clinical symptoms consisted of watery diarrhea, hyperthermia, anorexia, and severe dyspnea. The pathological and histological findings were very similar to those observed in human legionellosis. Legionella pneumophila serogroup 1 (SG1) and SG10 were isolated from the calf’s lung, and L. pneumophila SG1 was isolated from the calf’s liver. L. pneumophila SG1 was also demonstrated in the lung tissue by immunofluorescence and immunohistochemical examinations. Nine of 10 L. pneumophila SG1 isolates belonged to the Olda subtype, and 1 belonged to the Camperdown subtype. A very low prevalence of antibodies to Legionella was detected in cows and calves reared in the same herd. Cultures of aqueous sediment of an old electric water heater which supplied hot water for the feeding of the calves yielded L. pneumophila SG1. Four of the colonies tested belonged to the Olda subtype. Ten clinical and four environmental isolates were examined for the presence of plasmids. Nine of them were also examined by pulsed-field gel electrophoresis assay, and the same patterns were found for L. pneumophila SG1 Olda strains isolated from the calf and from the electric heater. This is the first report of a documented case of a naturally occurring Legionella pneumonia in an animal. Cattle probably act as accidental hosts for legionellae, much the same as humans.

In order to clarify the supposed involvement of urban pigeons (Columba livia livia) in the epidemiology of Lyme disease, the presence of antibodies against Borrelia burgdorferi and Borrelia anserina in pigeons' sera, collected in 12 areas of northern and central Italy, was evaluated. This evaluation was carried out using a classic immunofluorescence assay (IFA), a surface immunofluorescence assay (SIFA) and a standard Western Blot (WB) assay. A total of 104 out of 3,186 (3.26%) serum samples were positive for both spirochetes when tested by IFA, with titres ranging from 1/40 to 1/1280. All positive specimens showed the same or a higher reactivity against B. anserina than against B. burgdorferi. Of the IFA positive samples, 30 were tested by WB and SIFA to evaluate further the specificity of the antibody response, i.e. to try to clarify against which spirochete the antibodies were raised. The presence of antibodies against the 23 kDa protein exclusive to B. anserina, and against epitopes which are not surface-exposed and which are common to B. anserina and B. burgdorferi, was assessed by WB and SIFA. No serological evidence that B. burgdorferi can infect pigeons was found.

An outer surface lipoprotein of 22 kDa was identified in the avian pathogen Borrelia anserina Ni-NL by using antibody preparations reactive with bacterial surface-exposed proteins. Amino acid sequence analysis of the 22-kDa protein demonstrated 90% identity with VmpA of B. turicatae , suggesting that the protein belongs to the family of 20-kDa outer surface proteins of the genus Borrelia . All of the 60 chicks intramuscularly treated with antibodies specifically reacting with the 22-kDa protein and infected with strain Ni-NL were completely protected from infection, since no spirochetemia was detected, and from death. Control chicks were treated with immune sera raised against apathogenic strain B. anserina Es, which expresses a prominent 20-kDa polypeptide that is also a member of the Vmp family but does not cross-react immunologically with the 22-kDa protein of the Ni-NL strain. These animals, infected with B. anserina Ni-NL, showed a high degree of spirochetemia 10 days after infection, and all died between 14 and 21 days after infection. The results showed that the 22-kDa surface protein of B. anserina Ni-NL is a determinant of the pathogenic potential of the strain and also confirmed that only strain-specific antibodies are protective against B. anserina infection.