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A longitudinal study of Salmonella enterica infection was carried out in five Italian farrow-to-finish swine herds previously known to be infected by Salmonella. Five litters were randomly selected from each herd and in each litter six piglets were randomly selected and individually identified. Thus, the study included 30 pigs from each farm. At weaning, individual blood samples were collected for serological examination from all selected piglets and on the same day from all sows in the farrowing unit. Piglets were bled again at approximately 60, 90, 150, 210 and 270 days of life whereas the last blood sample was collected at slaughtering. In one of the herds, in which the duration of productive cycle was about 12 months, the last blood samples were collected at 350 days of life. With the same time scheduling, five pen pooled faecal samples were collected from each herd for bacteriological examination. At slaughtering, mesenteric lymph nodes were collected from each ear-tagged pig. Sero-prevalence (cut off S/P ratio 0.25) in sows varied from 93.8% to 100%. In four herds, sero-prevalence in piglets showed a similar profile with complete decline of maternal antibodies at day 60 and clear sero-conversion between day 90 and day 150. In one herd, sero-conversion was observed earlier and 56% of piglets were positive at day 90. The peak of sero-prevalence was observed between day 210 and day 270. Sero-prevalence at slaughtering varied from 66% to 100%. Salmonella was isolated from faecal samples in four of five herds. No Salmonella was isolated from mesenteric lymph nodes at slaughter in two of the herds. Culture prevalence from mesenteric lymph nodes in the other three herds ranged from 3.3% to 30%. This longitudinal study provides original information about epidemiological dynamics of Salmonella enterica infection in Italian swine herds in consideration of the unique extended fattening period typical of the Italian production. [ABSTRACT FROM AUTHOR]

Yersiniosis is the third most common reported zoonoses in Europe, with Y. enterocolitica and Y. pseudotuberculosis responsible for 98.66% and 0.94% of the confirmed human cases in 2013. From June 2013 to October 2014, 201 pigs at slaughter belonging to 67 batches were tested for Y. enterocolitica and Y. pseudotuberculosis in tonsils. Diaphragm muscle samples were tested for antibodies against Yersinia by a commercially available ELISA test. Y. enterocolitica 4/O:3 was detected in 55/201 pig tonsils (27.4%; 95% CI 23.1–37.1). The positive pigs came from 38/67 batches (56.7%) and were reared in 36/61 farms (59.0%). There was no statistical difference between farrow-to-finish and finishing farms. The mean count of Y. enterocolitica was 3.56 ± 0.85 log 10 CFU/g with a minimum of 2.0 log 10 CFU/g and a maximum of 4.78 log 10 CFU/g. Y. pseudotuberculosis was isolated from 4/201 pig tonsils (2.0%; 95% CI 0.0–4.5). Three isolates belonged to serotype O:3 and one to serotype O:1. The positive pigs belonged to 4/67 batches (6.0%) and came from finishing farms only. Y. pseudotuberculosis could be enumerated in one sample only (4.27 log 10 CFU/g). The ELISA test demonstrated that 56.1% of the meat juice samples were positive for Yersinia antibodies. Serological positivity was found in 67.9% (36/53) of the Y. enterocolitica - and 75.0% (3/4) of the Y. pseudotuberculosis positive pigs. A significant association was found between serological results and the presence of Y. enterocolitica in tonsils (OR = 1.97, p = 0.044). All the Y. enterocolitica 4/O:3 isolates were susceptible to amoxicillin-clavulanic acid, gentamicin, ceftazidime, ertapenem and meropenem, 94.5% to cefotaxime, 89.1% to kanamycin and 78.2% to tetracycline. The highest resistance rates were observed for ampicillin (100%), sulphonamides (98.2%) and streptomycin (78.2%). Y. pseudotuberculosis strains were sensitive to all the antimicrobials tested, i.e. amoxicillin, amoxicillin/clavulanic acid, azithromycin, cephalothin, cefoxitin, ceftriaxone, ciprofloxacin, nalidixic acid, sulphonamide, tetracycline and ticarcillin. The study shows that Italian fattening pigs are frequently infected with human pathogenic Y. enterocolitica 4/O:3. Although the isolation rate is slightly lower than in other European countries, the serological test demonstrates that the infection is widespread among pig population. In fact, seroprevalence is similar to other EU countries. The detection of Y. pseudotuberculosis serotypes O:1 and O:3 in pig tonsils is of concern. Since tonsils may represent a contamination source for pig meat at slaughter, further studies regarding human infections by both microbial species are strongly recommended. [ABSTRACT FROM AUTHOR]

From December 1999 to December 2000, 150 pigs were randomly selected in two large abattoirs of northern Italy. Caecal material and carcass swabs were collected and examined for Salmonella, Yersinia enterocolitica, and Escherichia coli O157. Tonsils were examined for Salmonella and Y. enterocolitica. Salmonella was isolated from the intestinal content of 55 (36.7%) specimens, from 8 (5.3%) tonsils, and from 9 (6.0%) carcasses. Ten different serotypes were detected; the more common were Salmonella derby (37.8%), Salmonella bredeney (21.6%), and Salmonella typhimurium (14.8%). S. typhimurium isolates that belonged to phage-types DT104 and DT208 were 45% and 27.3%, respectively; 18.2% belonged to U302 and 9.1% were non-typeable. Y. enterocolitica was detected in the intestinal matter of 6 (4.0%) slaughtered pigs and in 22 (14.7%) tonsils; however, this pathogen was not found on carcasses. The majority of Y. enterocolitica isolates (82.1%) belonged to serotype O:3 biotype 4, one (3.6%) belonged to serotype O:9, and 13% did not belong to any known biotype. Verocytotoxin-producing E. coli (VTEC) O157 was isolated from the intestinal content of one (0.7%) slaughtered pig and from one (0.7%) carcass; four (2.7%) faecal samples contained E. coli O157 strains negative for the presence of both eae and VT genes. [Copyright &y& Elsevier]