Occurrence of Yersinia enterocolitica and Campylobacter spp. in slaughter pigs and consequences for meat inspection, slaughtering, and dressing procedures

Nano-coating with silicon dioxide to reduce the occurrence of bacterial contamination in a pig abattoir drinking system

A recently discovered source for infection of slaughter pigs, and thus entry for bacteria into the food chain, is the installed drinking equipment in lairage pens of pig abattoirs. To mitigate this, nano-coating of stainless steel, currently used in human medicine fields as well as in other parts of the food chain, appears as promising technology. In this study, silicon dioxide nano-coating was applied to six drinkers and installed for one and three months in a lairage of a pig abattoir, while results were compared with those of drinkers that had not been nano-coated. Laboratory examination of eight sample types related to the drinkers was conducted for total aerobic plate count, Enterobacteriaceae count, Pseudomonas spp. count, Salmonella presence, pathogenic Yersinia enterocolitica presence, Listeria monocytogenes presence and methicillin-resistant Staphylococcus aureus presence. The nipple drinker, which the pigs take into their mouth for drinking, was then examined using scanning electron microscopy and elemental analysis. The nano-coating did not produce statistically significant reductions in the loads or presence of these bacteria compared to the same but uncoated drinking equipment used under the same conditions. Further studies should focus on the implementation of combined methods, such as nano-coating and sanitary treatment, as well as modifications to the coating itself, to produce meaningful reductions of the bacterial loads on/in abattoir lairage drinking equipment.

Relevant foodborne bacteria associated to pork production chain

Foodborne diseases affect millions of people globally, resulting in a huge number of hospitalizations and deaths. In this context, laboratory-based research is crucial to identify the major pathogens as well as the relevance of each one for distinct food production chains. Pork meat is very popular, being the most consumed meat in many countries and its inspection at the slaughterhouse is the main component of surveillance to protect consumers. Healthy pigs may carry pathogenic and antibiotic resistant bacteria that can be subsequently transferred to humans through the consumption of contaminated meat. Further, the food processing environment can harbor pathogenic persistent bacteria, representing a risk of cross-contamination to pork meat, demanding strict slaughtering procedures. Among these foodborne bacteria, Salmonella, Yersinia enterocolitica, Escherichia coli, Campylobacter spp., Listeria monocytogenes and Staphylococcus aureus are the most relevant in the pork production chain. Molecular subtyping has been fundamental for pathogen detection and also to track transmission, and nowadays it is a key component of the efforts to prevent and control foodborne diseases. In this chapter, characteristics of these major foodborne bacteria associated to pork meat will be addressed, including their occurrence and importance along the pork production chain, worldwide distribution, typing, as well as control and prevention measures from farm to fork.

Lessons Learned and Outcomes from Risk-Based Modernisation of Post-Mortem Inspection and Disposition Criteria of Beef, Sheep, Goat, and Pig Carcasses in Australia

The lessons learned from reviewing national risk assessments to modernise the Australian Standard for the post-mortem inspection and disposition judgement of beef, sheep, goat, and pig carcases are discussed. The initial risk profiles identified priorities for quantitative assessments. Broadly, the main difficulty encountered was the paucity of quantified performance for the current inspection. Resolving this involved acquiring gross abnormality data representing regional production/proportional abattoir volumes, the range of gross abnormalities appearing nationally, proportional occurrence at carcase sites, and seasonality to enable the comparison of procedures. The methodologies followed the Codex Alimentarius Commission's risk assessment guidelines and are fully documented in the associated publications. The evidence and discussion are provided for the associated challenges experienced, including preventing contamination, the use of food chain information to support amendment, inspection as a part of industry Quality Assurance programmes, and opportunities to improve inspector training. The criteria considered by the Competent Authority for the determination of the equivalence of alternative post-mortem inspection techniques included comparisons of public health risk, non-detection rates for gross abnormalities, and microbial contamination resulting from inspection activities, as appropriate. Most of the gross abnormalities detected arose from animal health and welfare conditions affecting wholesomeness and did not present as food safety hazards. The non-detection rates between the current and alternative inspection (observation) were negligible. A quantitative risk assessment for Cysticercus bovis was conducted. Carcases with multiple gross abnormalities predominantly reflected historic infections (prior septicaemia), where trimming achieved wholesomeness unless they were cachexic.

Drinking Pipes and Nipple Drinkers in Pig Abattoir Lairage Pens-A Source of Zoonotic Pathogens as a Hazard to Meat Safety

The water distribution system in the lairage pens of abattoirs could act as a route of contamination for produced meat. In this study, biofilm formation and the occurrence of specific pathogens in drinking equipment was investigated in different lairage pens in a German commercial pig abattoir. Samples of the water and the drinkers in different locations were microbiologically cultivated and examined. After new drinking equipment had been installed for one month, three months and five years, biofilm formation was detectable, and retrograde growth from the nipple drinkers was seen up to the connection with the main water distribution system. In particular, Enterobacteriaceae and Pseudomonas spp. were found in all samplings of the nipple drinkers. Zoonotic pathogens, Salmonella, pathogenic Yersinia enterocolitica and methicillin-resistant Staphylococcus aureus, were also isolated from the nipple drinkers, while Listeria monocytogenes was not detected via microbial cultivation methods in any of the samples. Since the pigs take the contaminated nipple drinkers into their mouths to drink, or drink contaminated water containing the pathogens, transmission and even infection of the pigs in the lairage can be assumed. This could consequently lead to contamination or cross-contamination of the meat during slaughter and processing and to a public health risk.

Effects of post-mortem inspection techniques change on the detection capability of low public health impact diseases of slaughtered pigs: A quasi-experimental study

Slaughtered animals are regularly submitted to post-mortem inspection to ensure that all the edible parts are fit for human consumption. According to Regulation (EU) No 219/2014, pig carcasses inspection is exclusively visual as palpation and incision could lead to cross-contamination and spread of relevant zoonotic agents. However, when compared to incision and palpation, the visual method is characterized by low sensitivity; thus, the omission of incision and palpation could lead to a reduced detection capability of organic lesions. This study aims to assess the effectiveness of exclusively visual inspection to mark pulmonary and hepatic lesions associated with low public health impact diseases in pork carcasses. A quasiexperimental- before/after research protocol has been used. All the post-mortem inspections have been carried out in a slaughterhouse located in the province of Teramo (IT), on 7,764 swine from 2011 to 2017. Carcasses undergone the only visual inspection have shown a statistically significant reduction (pvalue <0.0001) in the diagnosis of hepatic (decrease of 59%) and pulmonary diseases (decrease of 38. 5%). To overcome the limits of the low sensitivity of the visual inspection, as well as the inter-operator diagnostic variability, the high number of carcasses examined is proposed as a factor conferring external validity to the study, which provides quantitative evidence in support of the causal association between the modified inspection technique and the reduced diagnostic capacity. A further support derives from the assessment of the prevalence of hepatic and pulmonary diseases in species for whom the inspection technique is not changed.

Yersinia enterocolitica in wild and peridomestic rodents within Great Britain, a prevalence study

Yersinia enterocolitica is a human pathogen transmitted via the faecal-oral route among animals and humans and is a major foodborne public health hazard. This study explores the role of Y. enterocolitica transmission at the livestock-wildlife interface and investigates the potential role wild and peridomestic rodents play as a source of this zoonotic pathogen. The total of 342 faecal samples collected from the seven rodent species and one insectivore was examined using an optimized protocol to culture and identify Y. enterocolitica. Positive samples were also bioserotyped for grouping and determination of sample pathogenicity. Wildlife species sampled in this study were separated into two sample groups: randomly sampled (brown rats, house mice, wood mice, bank voles, field voles and the common shrew), as well as targeted sampling (red and grey squirrels). The overall prevalence of Y. enterocolitica in the randomly sampled population was 3.73%. Brown rats were chosen as sentinel species and tested to determine if location (pig farm vs non-pig farm) was a significant factor affecting Y. enterocolitica prevalence. In this study, location was not significant. All positive samples were found to be of biotype 1A, deemed non-pathogenic. Three of the samples were serotype 09, six were serotype 27 and five had an unidentifiable serotype. This study represents the first time Y. enterocolitica has been identified in these species of wildlife within mainland Britain. In addition, this study's findings are entirely novel and overall with regard to field voles and common shrews. However, the role of wild and peridomestic rodents in the transmission of pathogenic Y. enterocolitica remains unknown, as this study was unable to detect the presence of pathogenic Y. enterocolitica strains in these species.

Adding value to food chain information: using data on pig welfare and antimicrobial use on-farm to predict meat inspection outcomes

BACKGROUND

Using Food Chain Information data to objectively identify high-risk animals entering abattoirs can represent an important step forward towards improving on-farm animal welfare. We aimed to develop and evaluate the performance of classification models, using Gradient Boosting Machine algorithms that utilise accurate longitudinal on-farm data on pig health and welfare to predict condemnations, pluck lesions and low cold carcass weight at slaughter.

RESULTS

The accuracy of the models was assessed using the area under the receiver operating characteristics (ROC) curve (AUC). The AUC for the prediction models for pneumonia, dorsocaudal pleurisy, cranial pleurisy, pericarditis, partial and total condemnations, and low cold carcass weight varied from 0.54 for pneumonia and 0.67 for low cold carcass weight. For dorsocaudal pleurisy, ear lesions assessed on pigs aged 12 weeks and antimicrobial treatments (AMT) were the most important prediction variables. Similarly, the most important variable for the prediction of cranial pleurisy was the number of AMT. In the case of pericarditis, ear lesions assessed both at week 12 and 14 were the most important variables and accounted for 33% of the Bernoulli loss reduction. For predicting partial and total condemnations, the presence of hernias on week 18 and lameness on week 12 accounted for 27% and 14% of the Bernoulli loss reduction, respectively. Finally, AMT (37%) and ear lesions assessed on week 12 (15%) were the most important variables for predicting pigs with low cold carcass weight.

CONCLUSIONS

The findings from our study show that on farm assessments of animal-based welfare outcomes and information on antimicrobial treatments have a modest predictive power in relation to the different meat inspection outcomes assessed. New research following the same group of pigs longitudinally from a larger number of farms supplying different slaughterhouses is required to confirm that on farm assessments can add value to Food Chain Information reports.

Meat Safety from Farm to Slaughter—Risk-Based Control of Yersinia enterocolitica and Toxoplasma gondii

The implementation of the traditional meat safety control system has significantly contributed to increasing food safety and public health protection. However, several biological hazards have emerged in meat production, requiring a comprehensive approach to their control, as traditional methods of meat inspection at the slaughterhouse are not able to detect them. While national control programs exist for the most important meat-related hazards, similar data are still lacking for certain neglected threats, such as Yersinia enterocolitica or Toxoplasma gondii. The obstacle in controlling these hazards in the meat chain is their presence in latently infected, asymptomatic animals. Their effective control can only be achieved through systematic preventive measures, surveillance or monitoring, and antimicrobial interventions on farms and in slaughterhouses. To establish such a system, it is important to collect all relevant data on hazard-related epidemiological indicators from the meat chain, which should provide relevant guidance for interventions at the harvest and post-harvest stage. The proposed approach is expected to improve the existing system and provide many opportunities to improve food safety and public health.

Presence and Characterization of Zoonotic Bacterial Pathogens in Wild Boar Hunting Dogs (Canis lupus familiaris) in Tuscany (Italy)

Domestic dogs (Canis lupus familiaris) used for wild boar (Sus scrofa) hunting may represent incidental hosts for several zoonotic pathogens. This investigation aimed to evaluate the presence of anti-Leptospira antibodies and the occurrence, antimicrobial resistance, and virulence of Salmonella spp., Yersinia enterocolitica, and Listeria monocytogenes in sera and rectal swabs collected from 42 domestic hunting dogs in the Tuscany region (Italy). Regarding Leptospira, 31 out of 42 serum samples (73.8%) were positive and serogroup Pomona was the most detected (71.4%) at titers between 1:100 and 1:400. Four Salmonella isolates (9.52%) were obtained, all belonging to serotype Infantis; two of them showed antimicrobial resistance to streptomycin, while pipB and sopE presence was assessed in all but one isolate. Concerning Yersinia enterocolitica, seven isolates (16.7%) were obtained, six belonging to biotype 1 and one to biotype 4. Resistance to amoxicillin-clavulanic acid, cephalothin, and ampicillin was detected. Biotype 4 presented three of the virulence genes searched (ystA, ystB, inv), while isolates of biotype 1 showed only one gene. No Listeria monocytogenes was isolated from dog rectal swabs. The results suggest that hunting dogs are exposed to different bacterial zoonotic agents, potentially linked to their work activity, and highlight the possible health risks for humans.

Bacterial community analysis for investigating bacterial transfer from tonsils to the pig carcass

Tonsils in the oral cavity are an important source of contamination during pig slaughter, but have not received as much attention as faecal contamination. In the present study, ten pigs were sampled from tonsils, faeces and three different areas on each carcass. The samples were analysed by both culturing of Escherichia coli and Yersinia enterocolitica and by 16S rRNA gene sequencing to characterize the bacterial communities. Comparing culture data from deep tonsil tissue and tonsil surface showed similar numbers of E. coli but significantly higher numbers of Y. enterocolitica in the deep tissue samples. Microbiota analysis showed similar bacterial communities in the two sample types at phylum level, while comparison at genus level showed significant differences between the relative abundance of several genera in the two sample types. The finding of a significantly higher relative abundance of Yersinia in tonsil tissue compared to tonsil surface supported the culture analysis. The microbiota analysis also investigated characteristics of the bacterial community that could discriminate bacterial transfer from tonsils and faeces to the carcass during slaughter. The microbiota analyses demonstrated that Fusobacteria and Proteobacteria are the most abundant phyla in tonsils, while Firmicutes showed the highest relative abundance in faeces. The dominating phylum on carcasses was Proteobacteria. Besides Proteobacteria, the swabbing area on the forepart of the carcass, showed a higher relative abundance of Firmicutes and Fusobacteria compared to swabbing areas on the rear part and mid-section of the carcass. Principal coordinate analysis showed clear clustering of samples based on sample source (tonsils, faeces and carcass). Carcass swab samples from the forepart tended to cluster closer to the tonsil samples compared to carcass swab samples from the rear part and mid-section. Identification of the genera Fusobacterium, Moraxella, Actinobacillus and non-E. coli genera of the family Enterobacteriaceae in carcass swabs could indicate tonsil contamination, while faecal contamination would more likely include higher prevalence of bacteria belonging to the class of Clostridia. The present study supports that it is possible to identify bacterial groups that are indicative for either tonsil or faecal carcass contamination. The level and composition of Enterobacteriaceae on the carcasses did, however, indicate that other sources of meat contamination than tonsils and faeces may be important, such as the process environment.

Evaluation of selected phenotypic features among Campylobacter sp. strains of animal origin

A total of 43 Campylobacter isolates from poultry, cattle and pigs were investigated for their ability to form biofilm. The studied strains were also screened for motility, adhesion and invasion of Caco-2 cells as well as extracellular DNase activity. The relation between biofilm formation and selected phenotypes was examined. Biofilm formation by the tested strains was found as irrespective from their motility and not associated with colonization abilities of human Caco-2 cells. Results of our study show that Campylobacter isolates from various animal sources are able to form biofilm and invade human Caco-2 cells in vitro.

Antibiotic Resistance of Campylobacter Recovered from Faeces and Carcasses of Healthy Livestock

Campylobacter is of major significance in food safety and human and veterinary medicine. This study highlighted resistance situation in the area of veterinary public health in Ghana. Using selective mCCDA agar, isolates were confirmed phenotypically on API CAMPY and genotypically by multiplex PCR of IpxA gene. The susceptibility profile of species to common and relevant antibiotics was determined by the Kirby-Bauer disk diffusion method. Cattle, sheep, goat, and pig faecal samples analysed, respectively, yielded 13.2% (16/121), 18.6% (22/102), 18.5% (25/135), and 28.7% (29/101) Campylobacter species while 34.5% (38/110), 35.9% (42/117), 23.9% (32/134), and 36.3% (37/102) were, respectively, recovered from the carcasses. Species identified in faeces were C. jejuni 35.8% (33/92), C. jejuni subsp. doylei 4.3% (4/92), C. coli 47.8% (44/92), and C. lari 12.0% (11/92). Species discovered in carcasses were C. jejuni 83.9% (125/149), C. jejuni subsp. doylei 2.0% (3/149), C. coli 6.0% (9/149), and C. lari 8.1% (12/149). Resistance ranged from 92 to 97% to the β-lactams, 7 to 69% to the quinolones, 0 to 44% to the aminoglycosides, 97 to 100% to erythromycin, 48 to 94% to tetracycline, 45 to 88% to chloramphenicol, and 42 to 86% to trimethoprim/sulfamethoxazole as 0% resistance was observed against imipenem.

Determination of the cytotoxic activity of Campylobacter strains isolated from bovine and swine carcasses in north-eastern Poland

The study was carried out to determine the cytotoxin production by Campylobacter spp. isolated from slaughtered cattle and swine in north-eastern Poland. In total three commercial slaughterhouses were sampled during one year. Carcass swabs were taken to detect the level of Campylobacter spp. contamination. Campylobacter spp. was found in 50 (34%) out of 147 swine carcasses examined. PCR analysis revealed 4 (8%) isolates to be C. jejuni, and 46 (92%) to be C. coli. From a total of 373 bovine carcasses, Campylobacter spp. were isolated from 49 (13.1%) samples. The results regarding the occurrence of cdt genes associated with cytotoxicity indicated that 100% of C. jejuni and 67.4% C. coli obtained from pigs had all three cdtA, cdtB and cdtC genes. In case of C. jejuni strains isolated from cattle all cdt genes were confirmed in 93.9% isolates. The isolates possessesing all cdt genes had higher cytotoxic activity against cell lines used. The isolates both from cattle and swine were characterized by the highest cytotoxicity against HeLa cells. The values obtained reached 80.8% for C. jejuni isolates from cattle and 76.2% for C. jejuni and 69.0% for C. coli isolates from swine. High prevalence of cytotoxicity in Campylobacter spp. indicates a significant epidemiological role of this pathogen in human infections.

Bayesian Estimation of the True Prevalence and of the Diagnostic Test Sensitivity and Specificity of Enteropathogenic Yersinia in Finnish Pig Serum Samples

Bayesian analysis was used to estimate the pig's and herd's true prevalence of enteropathogenic Yersinia in serum samples collected from Finnish pig farms. The sensitivity and specificity of the diagnostic test were also estimated for the commercially available ELISA which is used for antibody detection against enteropathogenic Yersinia. The Bayesian analysis was performed in two steps; the first step estimated the prior true prevalence of enteropathogenic Yersinia with data obtained from a systematic review of the literature. In the second step, data of the apparent prevalence (cross-sectional study data), prior true prevalence (first step), and estimated sensitivity and specificity of the diagnostic methods were used for building the Bayesian model. The true prevalence of Yersinia in slaughter-age pigs was 67.5% (95% PI 63.2-70.9). The true prevalence of Yersinia in sows was 74.0% (95% PI 57.3-82.4). The estimates of sensitivity and specificity values of the ELISA were 79.5% and 96.9%.

Association between microbiological and serological prevalence of human pathogenic Yersinia spp. in pigs and pig batches

Pigs are the main reservoir of human pathogenic Y. enterocolitica, and the microbiological and serological prevalence of this pathogen differs between pig farms. The infection status of pig batches at moment of slaughter is unknown while it is a possibility to classify batches. A relation between the presence of human pathogenic Yersinia spp. and the presence of antibodies could help to predict the infection of the pigs prior to slaughter. Pigs from 100 different batches were sampled. Tonsils and pieces of diaphragm were collected from 7047 pigs (on average 70 pigs per batch). The tonsils were analyzed using a direct plating method and the meat juice collected from the pieces of diaphragm was analyzed by Enzyme Linked ImmunoSorbent Assay. The microbiological and serological results were compared using a mixed-effects logistic regression at pig and batch level. Yersinia spp. were found in 2031 (28.8%) pigs, antibodies were present in 4692 (66.6%) pigs. According to the logistic regression, there was no relation at pig level between the presence of Yersinia spp. in tonsils and the presence of antibodies. Contrarily, at batch level, a mean activity value of 37 Optical Density (OD)% indicated a Yersinia spp. positive farm and the microbiological prevalence in pig batches could be estimated before shipment to the slaughterhouse. This offers the opportunity to classify batches based on their potential risk to contaminate carcasses with human pathogenic Yersinia spp.

Prevalence of Campylobacter spp. in Retail Chicken, Turkey, Pork, and Beef Meat in Poland between 2009 and 2013

The purpose of the present study was to determine the prevalence of thermophilic Campylobacter in poultry, pork, and beef meat at the retail level and to identify the main categories of meat representing the most significant reservoirs of Campylobacter. A monitoring study was conducted throughout Poland from 2009 to 2013. A total of 1,700 fresh meat samples were collected from supermarkets, large retail outlets, and smaller stores. Thermophilic Campylobacter species were detected in 690 (49.3%) of 1,400 poultry samples collected from retail trade. Strains were isolated from 50.2 and 41.1% of raw chicken and turkey meat samples, respectively, and from 50.1 and 42.6% of raw chicken and turkey giblets. The incidence of Campylobacter spp. on pork (10.6%) and beef (10.1%) was significantly lower than on poultry. Campylobacter jejuni was the most prevalent Campylobacter species in chicken (46.6%), pork (68.6%), and beef (66.7%), and Campylobacter coli was the most frequently isolated Campylobacter species in turkey meat (71.2%). This study revealed that retail raw meats are often contaminated with Campylobacter; however, the prevalence of these pathogens is markedly different in different meats. Raw retail meats are potential vehicles for transmitting foodborne diseases, and our findings stress the need for increased implementation of hazard analysis critical control point programs and consumer food safety education efforts.

Prevalence of Salmonella spp. and Yersinia enterocolitica in/on tonsils and mandibular lymph nodes of slaughtered pigs

A total of 156 tonsils and 156 mandibular lymph nodes from fattening pigs originating from 13 farms were sampled in Croatian slaughterhouses and examined for Salmonella spp. (n=78 per organ) and Yersinia enterocolitica (n=78 per organ) by cultural methods. Salmonella was isolated from two tonsils only, both originated from animals from the same farm (5.12%), while Y. enterocolitica were recovered from 26 tonsils (33.33%) which could be traced back to 10 farms. Salmonella was absent in mandibular lymph nodes, and Y. enterocolitica was isolated from eight lymph nodes (10.25%) which originated from six farms. Y. enterocolitica was present inside the lymph nodes of two pigs. The high prevalence of Y. enterocolitica in/on pig tonsils could be the result of cross-contamination during splitting the carcasses with head. This procedure may result in higher prevalence of Y. enterocolitica on surface of mandibular lymph nodes than in their depth. Traditional veterinary postmortem examination of pig halves will not necessarily contribute to cross-contamination with Salmonella or Yersinia under conditions of present slaughter practice.

Within-batch prevalence and quantification of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis in tonsils of pigs at slaughter

Yersiniosis is a common bacterial zoonosis in Europe and healthy pigs are known to be the primary reservoir of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis. However, little information is available about the prevalence of these pathogens within pig batches at time of slaughter. The tonsils of 7047 fattening pigs, belonging to 100 farms, were aseptically collected immediately after evisceration in two Belgian slaughterhouses. The batch size varied between 70 and 930 pigs. On average, 70 pigs were sampled per batch. The tonsils were examined by direct plating on cefsulodin-irgasan-novobiocin (CIN) agar plates and the number of suspect Yersinia colonies was counted. Pathogenic Y. enterocolitica serotype O:3 were found in tonsils of 2009 pigs (28.5%), originating from 85 farms. The within-batch prevalence in positive farms ranged from 5.1 to 64.4%. The number of Y. enterocolitica in positive pigs varied between 2.01 and 5.98 log10 CFU g(-1) tonsil, with an average of 4.00 log10 CFU g(-1) tonsil. Y. pseudotuberculosis was found in seven farms, for which the within-batch prevalence varied from 2 to 10%. In five of these farms, both Y. enterocolitica and Y. pseudotuberculosis were simultaneously present. Human pathogenic Yersinia spp. are widespread in slaughter pig batches in Belgium as 87% of the tested batches were infected with these pathogens at the time of slaughter. The large variation of the prevalence between batches may lead to different levels of contamination of carcasses and risks for public health.

Behavior of Yersinia enterocolitica in the presence of the bacterivorous Acanthamoeba castellanii

Free-living protozoa play an important role in the ecology and epidemiology of human-pathogenic bacteria. In the present study, the interaction between Yersinia enterocolitica, an important food-borne pathogen, and the free-living amoeba Acanthamoeba castellanii was studied. Several cocultivation assays were set up to assess the resistance of Y. enterocolitica to A. castellanii predation and the impact of environmental factors and bacterial strain-specific characteristics. Results showed that all Y. enterocolitica strains persist in association with A. castellanii for at least 14 days, and associations with A. castellanii enhanced survival of Yersinia under nutrient-rich conditions at 25°C and under nutrient-poor conditions at 37°C. Amoebae cultivated in the supernatant of one Yersinia strain showed temperature- and time-dependent permeabilization. Intraprotozoan survival of Y. enterocolitica depended on nutrient availability and temperature, with up to 2.8 log CFU/ml bacteria displaying intracellular survival at 7°C for at least 4 days in nutrient-rich medium. Transmission electron microscopy was performed to locate the Yersinia cells inside the amoebae. As Yersinia and Acanthamoeba share similar ecological niches, this interaction identifies a role of free-living protozoa in the ecology and epidemiology of Y. enterocolitica.

Probable transmission of Yersinia enterocolitica from a pet dog with diarrhoea to a 1-year-old infant

We report a highly probable case of transmission of a Yersinia enterocolitica from a pet puppy dog, adopted from a Spanish asylum, to a 1-year-old girl. After several weeks of diarrhoea, a PCR detecting enteropathogenic bacteria was performed on the faeces, revealing Y enterocolitica. Following cultures yielded a Y enterocolitica biotype 4, serotype O:3 in the faeces of the girl as well as puppy dog. Despite antibiotic treatment, symptoms and shedding of the organism in the faeces endured during a 2 month period.

Antibiotic susceptibility of Salmonella, Campylobacter coli, and Campylobacter jejuni isolated from Northern German fattening pigs

This study was conducted to assess the antimicrobial susceptibility rate of Salmonella and Campylobacter spp. isolated from Northern German fattening pigs. From 540 lymph node samples, 16 Salmonella Typhimurium, 1 Salmonella Brandenburg, 37 Campylobacter coli, and 11 Campylobacter jejuni strains were isolated. Antibiotic susceptibility testing was carried out by the broth dilution method. The 14 tested antibiotics for Salmonella were ampicillin, cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, colistin, florfenicol, gentamicin, kanamycin, nalidixic acid, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim. The eight tested antibiotics for Campylobacter spp. were ampicillin, ampicillin-sulbactam (2:1), ciprofloxacin, erythromycin, gentamicin, nalidixic acid, sulfamethoxazole-trimethoprim (1:19), and tetracycline. In total, 93.7% (n = 16) of Salmonella Typhimurium, 75.7% (n = 37) of C. coli, and 54.5% (n = 11) of C. jejuni isolates were resistant to at least one of the tested antibiotics. Multiresistance to three antibiotics was observed in 75% of Salmonella Typhimurium, 16.2% of C. coli, and 0% of C. jejuni isolates. Pansusceptibility was detected in 6.3% of Salmonella Typhimurium, 24.3% of C. coli, and 45.5% of C. jejuni isolates. Multiresistance is defined as resistance to three or more antibiotics, and pansusceptibility is defined as not having resistance to any antibiotic. Regarding drugs of last resort--cefotaxime, ciprofloxacin, and nalidixic acid--resistance was not common among Salmonella (6.3%). The resistance rate of Campylobacter spp. to last-resort drugs--erythromycin, ciprofloxacin, and nalidixic acid--varied between species. The observed trend was not statistically significant. No C. coli isolates and few C. jejuni isolates (9.1%) were resistant to erythromycin. In contrast to C. jejuni, the C. coli isolates were more likely to be resistant to ciprofloxacin (9.1 and 18.9%, respectively) and nalidixic acid (0 and 13.5%, respectively). The same phenomenon was detected for tetracycline (27.3 and 62.2%, respectively), sulfamethoxazole (9.1 and 43.2%, respectively), and ampicillin (9.1 and 21.6%, respectively).

Detecção de fatores de virulência em estirpes de Campylobacter spp. isoladas de carcaças de suínos abatidos em frigoríficos

Isolaram-se estirpes de Campylobacter spp. em amostras de carcaças (n=65), fezes (n=65) e linfonodos mesentéricos (n=65) de suínos abatidos em frigoríficos do estado de São Paulo e detectaram, pela técnica da Multiplex-PCR, a presença do complexo de genes cdt, responsáveis pela expressão do fator de virulência da toxina CDT. Do total de 195 amostras de origem suína, Campylobacter spp. foi isolado de 31 (15,9%), sendo 29 (93,6%) de amostras de suabe retal, 1/65 (3,2%) de suabe de carcaça e um (3,2%) de linfonodo. Vinte e oito estirpes de C. coli foram positivas para a detecção dos genes cdt, e três estirpes de C. jejuni foram negativas para a detecção desses genes. Foi detectada, pela primeira vez no estado de São Paulo, a presença dos genes cdt em 100% das estirpes de Campylobacter coli provenientes de suínos abatidos em frigoríficos.

Experimental infection of weaned piglets with Campylobacter coli--excretion and translocation in a pig colonisation trial

Campylobacter (C.) is one of the most common food-borne pathogen causing bacterial enteric infections in humans. Consumption of meat and meat products that have been contaminated with Campylobacter are the major source of infection. Pigs are a natural reservoir of Campylobacter spp. with C. coli as the dominant species. Even though some studies focussed on transmission of C. coli in pig herds and the excretion in faeces, little is known about the colonisation and excretion dynamics of C. coli in a complex gut microbiota present in weaned piglets and the translocation to different tissues. Therefore, an experimental trial was conducted to evaluate the colonisation and translocation ability of the porcine strain C. coli 5981 in weaned pigs. Thus, ten 35 days old piglets were intragastrically inoculated with strain C. coli 5981 (7 × 10(7)CFU/animal) encoding resistances against erythromycin and neomycin. Faecal samples were taken and C. coli levels were enumerated over 28 days. All piglets were naturally colonised with C. coli before experimental inoculation, and excretion levels ranged from 10(4) to 10(7)CFU/g faeces. However, no strain showed resistances against the additional antimicrobials used. Excretion of C. coli 5981 was seen for all piglets seven days after inoculation and highest counts were detectable ten days after inoculation with 10(6)CFU/g faeces. Post-mortem, translocation and subsequent invasion of luminal C. coli was observed for gut tissues of the small intestine and for the gut associated lymphatic tissues, such as jejunal mesenteric lymph nodes and tonsils as well as for spleen and gall bladder. In conclusion, this pig colonisation trial offers the opportunity to study C. coli colonisation in weaned piglets using the porcine strain C. coli 5981 without the need for gnotobiotic or specific pathogen-free animals.