The relation between farm specific factors and prevalence of Clostridium difficile in slaughter pigs

Foodborne ingestion through pork products of Clostridium difficile has been suggested a possible route of transmission of C difficile from pigs to humans. To determine whether C. difficile bacteria are present in the intestines of slaughter pigs, rectum contents of 677 slaughter pigs from 52 farms were collected at the slaughterhouse. Data on farm specific factors were collected and the association of these factors with the presence of C. difficile in pig herds from 39 farms was assessed. The prevalence of C. difficile and the ribotypical diversity that were found in this study were much higher than previously reported in literature, with an overall C. difficile prevalence of 8.6% (58/677). Sixteen distinct C. difficile ribotypes were identified, predominantly type 078 (31.0%, 18/58). This type is also commonly found in humans with C. difficile infection (CDI). Both on individual pig level and on herd level, no significant difference between the prevalence of C. difficile in pigs derived from conventional or organic farming types was detected. Farm system, size, and presence of other animal species on the farm did not result in significant different prevalences of C. difficile.     

Clostridium difficile: prevalence in horses and environment,and antimicrobial susceptibility

REASONS FOR PERFORMING STUDY: Clostridium difficile has been associated with acute colitis in mature horses. OBJECTIVES: To survey C. difficile colonisation of the alimentary tract with age, occurrence of diarrhoea and history of antibiotic therapy; and to study the occurrence and survival of C. difficile in the environment and antimicrobial susceptibility of isolated strains. METHODS: A total of 777 horses of different breeds, age and sex were studied. Further, 598 soil samples and 434 indoor surface samples were examined. Antimicrobial susceptibility of 52 strains was investigated by Etest for 10 antibiotics. RESULTS: In horses that developed acute colitis during antibiotic treatment, 18 of 43 (42%) were positive to C. difficile culture and 12 of these (28%) were positive in the cytotoxin B test. Furthermore, C. difficile was isolated from a small number of diarrhoeic mature horses (4 of 72 [6%]) with no history of antibiotic treatment, but not from 273 healthy mature horses examined or 65 horses with colic. An interesting new finding was that, in normal healthy foals age < 14 days, C. difficile was isolated from 1/3 of foals (16 of 56 [29%]). All older foals (170) except one were negative. Seven of 16 (44%) nondiarrhoeic foals treated with erythromycin or gentamicin in combination with rifampicin were also excretors of C. difficile. On studfarms, 14 of 132 (11%) outdoor soil samples were positive for C. difficile in culture, whereas only 2 of 220 (1%) soil samples from farms with mature horses were positive for C. difficile (P = < 0.001). By PCR, it was demonstrated that strains from the environment and healthy foals can serve as a potential reservoir of toxigenic C. difficile. The experimental study conducted here found that C. difficile survived in nature and indoors for at least 4 years in inoculated equine faeces. The susceptibility of 52 strains was investigated for 10 antibiotics and all were susceptible to metronidazole (MIC < or = 4 mg/l) and vancomycin (MIC < or = 2 mg/l). CONCLUSIONS: C. difficile is associated with acute colitis in mature horses, following antibiotic treatment. Furthermore, C. difficile was isolated from 1 in 3 normal healthy foals age < 14 days. POTENTIAL RELEVANCE: Strains from healthy foals and the environment can serve as a potential reservoir of toxigenic C. difficile.     

Three-week summer period prevalence of Clostridium difficile in farm animals in a temperate region of the United States (Ohio)

The cross-sectional (period) prevalence of Clostridium difficile in 875 farm animals from 29 commercial operations during the summer of 2008 in Ohio, USA was quantified. Compared to an external referent population of intensively managed race horses (12.7%), intensively managed commercially mature food animals (poultry, cattle, swine; < 0.6%) were infrequent shedders of C. difficile (P < 0.00001) during the warmest weeks of 2008.     

Genotypic and phenotypic characterization of Clostridium perfringens and Clostridium difficile in diarrheic and healthy dogs

The objectives of this study were to examine the potential roles of Clostridium difficile and enterotoxigenic Clostridium perfringens in diarrhea in dogs by comparison of isolation, determination of toxin status via enzyme-linked immunosorbent assay (ELISA), and application of multiplex polymerase chain reaction (PCR). These techniques were used to evaluate fecal specimens in 132 healthy and diarrheic dogs. These dogs were prospectively evaluated by grouping them into the following 3 categories: hospitalized dogs with diarrhea (n = 32), hospitalized dogs without diarrhea (n = 42), and apparently healthy outpatient dogs without diarrhea (n = 58). All fecal specimens were cultured using selective media for C difficile, Salmonella spp., and Campylobacter spp. and selective media after heat shock for C perfringens. No significant difference was found in the isolation of C perfringens or C difficile among the 3 groups. A significant association was found between the presence of diarrhea and detection of C perfringens enterotoxin (CPE) or toxin A via ELISA for both C perfringens and C difficile, respectively. PCR performed on C difficile isolates for toxin A and toxin B genes revealed no significant differences among the 3 groups, but diarrheic dogs were significantly more likely to be positive for the enterotoxin gene of C perfringens. Based on the results of this study, the use of ELISA for detection of CPE in feces combined with the detection of enterotoxigenic fecal isolates obtained via heat shock provides the strongest evidence for the presence of C perfringens-associated diarrhea.     

Livestock-associated MRSA prevalence in veal calf production is associated with farm hygiene, use of antimicrobials, and age of the calves

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is highly prevalent in pork and veal production chains. In this study, we used data from a cross-sectional survey on 2151 calves from 102 veal calf farms to identify potential risk factors, with the goal of reducing MRSA prevalence by developing intervention strategies. Overall, calves from rose veal farms had a lower risk of LA-MRSA carriage than calves from white veal farms. Data were analysed separately for white and rose veal calves, because management systems of the two production chains were largely different. Group treatment with antimicrobials appeared to be a risk factor for MRSA carriage in white veal calves in univariate analyses, but was not included in the final multiple regression model that included age of the calves and rodent control. Number of start treatment days was positively associated with LA-MRSA carriage in rose veal calves, and was the only risk factor selected for the final multiple regression model for this group. Interpretation of the results from this cross-sectional study is complicated by the strong correlation between antimicrobial use, LA-MRSA carriage and age of the calves. Other age-related factors may be more influential. However, taken together these findings emphasize the need for prudent use of antimicrobials, and point to improvement of farm hygiene as a control measure.     

Cryptosporidium infection in a veal calf cohort in France: molecular characterization of species in a longitudinal study

ABSTRACT: Feces from 142 animals were collected on 15 farms in the region of Brittany, France. Each sample was directly collected from the rectum of the animal and identified with the ear tag number. Animals were sampled three times, at 5, 15 and 22 weeks of age. After DNA extraction from stool samples, nested PCR was performed to amplify partial 18S-rDNA and 60 kDa glycoprotein genes of Cryptosporidium. The parasite was detected on all farms. One hundred out of 142 calves (70.4%) were found to be parasitized by Cryptosporidium. Amplified fragments were sequenced for Cryptosporidium species identification and revealed the presence of C. parvum (43.8%), C. ryanae (28.5%), and C. bovis (27%). One animal was infected with Cryptosporidium ubiquitum. The prevalence of these species was related to the age of the animal. C. parvum caused 86.7% of Cryptosporidium infections in 5-week-old calves but only 1.7% in 15-week-old animals. The analysis of the results showed that animals could be infected successively by C. parvum, C. ryanae, and C. bovis for the study period. C. parvum gp60 genotyping identifies 6 IIa subtypes of which 74.5% were represented by IIaA15G2R1. This work confirms previous studies in other countries showing that zoonotic C. parvum is the dominant species seen in young calves.     

Mycoplasma ovis in captive cervids: prevalence, molecular characterization and phylogeny

Hemotrophic mycoplasmas (hemoplasmas) are bacteria that attach to red blood cells of mammals, leading to acute and/or subclinical disease in infected animals. It has been suggested that Mycoplasma ovis, a hemoplasma that infects sheep and goats worldwide, may also infect deer. The aim of this study was to evaluate whether South American deer are infected with M. ovis. EDTA-anticoagulated blood samples from a herd of 32 captive South American deer were collected. DNA extraction of blood samples was performed followed by PCR amplification of the 16S and 23S rRNA genes, and sequencing of products. Using M. ovis PCR, 27/31 (87%) were positive, including 21/22 Mazama nana; 2/3 Mazama americana and 4/6 Blastocerus dichotomus. Sequencing of the nearly entire 16S rRNA gene of 26/27 positive samples showed 98.2-98.8% identity to M. ovis of sheep (GenBank, AF338268) and 98.6-99.4% identity to M. ovis-like of a fawn (FJ824847); the 23S rRNA gene from one of these isolates and the fawn's had 97.6% identity. The remaining isolate had just 94.9% identity to the 16S rRNA gene of M. ovis and only 89.4% identity to the 23S rRNA gene of the fawn's M. ovis. This is the first report of M. ovis in captive South American deer, revealing a high prevalence of hemoplasma infection in these animals.     

Longitudinal study comparing the dynamics of Clostridium difficile in conventional and antimicrobial free pigs at farm and slaughter

Clostridium difficile is the leading cause of nosocomial diarrhea in humans and a major cause of enteritis in neonatal piglets, foals and calves. The aim of this longitudinal study was to determine and compare the prevalence, antimicrobial susceptibility, and toxinotype profiles of C. difficile isolated from pigs and their environment in the indoor conventional and outdoor antimicrobial free (ABF) production systems. Ten conventional and eight ABF cohorts of 35 pigs each and their environment were sampled at different stages of production at farm and slaughter. C. difficile prevalence in pigs was highest at the farrowing stage in both conventional (34%, 120/350) and ABF (23%, 56/244) systems, and decreased with age. This reduction in C. difficile prevalence in pigs at later stages of production mirrored the decreased prevalence in the farm environment. At slaughter, C. difficile was isolated at a low frequency from the carcasses and processing environment in both production systems. All but three isolates were resistant to ciprofloxacin (99%, 505/508), while 1.0% (5/508) and 6.0% (23/508) of isolates exhibited resistance to tetracycline and erythromycin, respectively. Toxinotype V (tcdA(+)tcdB(+)) was the predominant strain identified in both systems (conventional: 94%, 376/401; ABF: 82%, 88/107), while the rest were toxinotype XIII (tcdA(+)tcdB(+)). To conclude, we isolated antimicrobial resistant C. difficile regardless of antimicrobial use on the farm. Based on the phenotypic and genotypic similarity of C. difficile isolated in this study, we conclude that the unique production practices employed in conventional and ABF production systems have no impact on the pathogen population.     

Effect of a Probiotic on Prevention of Diarrhea and Clostridium difficile and Clostridium perfringens Shedding in Foals

Background

Up to 60% of foals develop diarrhea within 6 months after birth. Preventive measures are limited but potentially probiotics could be used.

Objective

To evaluate the effect of a newly designed probiotic on the incidence of foal diarrhea in a randomized field trial.

Animals

Seventy‐two healthy neonatal foals.

Methods

Randomized, placebo‐controlled field trial. Foals were administered a placebo or probiotic for 3 weeks and monitored for an additional week. A total of 3 fecal samples were taken from each foal at biweekly intervals. Statistical modeling was applied for comparison of incidence and duration of diarrhea and fecal shedding of Clostridium perfringens and Clostridium difficile between treatment and age groups.

Results

The overall incidence of diarrhea was 41 of 72 (59%) and did not differ (P = 0.37) between treatment groups. Foals treated with probiotics were more likely to develop diarrhea requiring veterinary intervention (P = 0.007). Age had a significant effect on incidence of diarrhea (P < 0.001); foals 8–15 days old having the highest probability of developing diarrhea. Duration of diarrhea and soft feces were not significantly different between groups. The prevalence of C. perfringens shedding was 55% with no difference between treatment groups (P = 0.23). The prevalence of C. difficile shedding was 11%.

Conclusion and Clinical Importance

There was no benefit of administering a 3‐week course of probiotics, but potential adverse effects were noted. Whether the probiotics lacked a clinical effect, or the choice of strains or dose was inadequate, is unknown. Clostridial shedding was not influenced by probiotics despite in vitro activity of probiotics.     

艰难梭菌毒素及致病基因的研究进展

艰难梭菌是一种革兰阳性厌氧芽胞梭菌,是人类肠道感染的主要致病菌,以肠道病理损伤及菌群失调为主的感染性疾病.使用抗菌药物后可导致艰难梭菌过度生长,分泌大量毒素A(肠毒素)和毒素B(细胞毒素),通过毒素介导致病.毒素A启动细胞损伤后,毒素B即可侵入肠黏膜,引起细胞病变,导致一系列与感染相关的临床表现.少数强毒株艰难梭菌还可以产生二元毒素,该毒素可以导致细胞骨架破坏,增强毒素A和毒素B的作用导致严重病变.研究发现,人和动物艰难梭菌之间具有同源性,成为人类感染艰难梭菌的传染源.对艰难梭菌产生毒素的致病机理进行综述,为治疗艰难梭菌感染提供依据.     

Epidemiology, clinical signs, histopathology and molecular characterization of canine leproid granuloma: a retrospective study of cases from Brazil

Thirty-eight cases of canine leproid granuloma were diagnosed between 2000 and 2008. Diagnosis was based upon clinical and histopathological findings and the presence of acid-fast bacilli in skin sections. The clinical lesions were localized predominantly on the pinnae and included papules, plaques and nodules, with or without ulceration. Boxer dogs were the breed most affected. Histopathological findings included nodular to diffuse pyogranulomatous, lymphoplasmocytic inflammatory infiltrates, with or without necrosis, localized in the dermis or subcutaneous tissue. The bacillary loading and morphology were variable among the lesions analysed. There was no significant correlation between bacterial load and histopathological pattern, dominant type of inflammatory infiltration or the amount of necrosis or giant cells. No correlation was observed between giant cells and histopathological pattern. In the majority of cases where a PCR-based assay was done, a novel mycobacterium species as the main aetiological agent was identified, as reported in previous studies.     

Antimicrobial susceptibility of Swedish, Norwegian and Danish isolates of Clostridium perfringens from poultry, and distribution of tetracycline resistance genes

This study was undertaken to determine the in vitro susceptibility of Clostridium perfringens, isolated from poultry to antimicrobials used in poultry production. The minimal inhibitory concentration (MIC) of eight antimicrobials, including the ionophoric coccidiostat narasin, was determined for 102 C. perfringens isolates, 58 from Sweden, 24 from Norway and 20 from Denmark. Susceptibility to each antimicrobial compound was determined by broth microdilution. The isolates were obtained from broilers (89), laying hens (9) and turkeys (4), affected by necrotic enteritis (NE) or by C. perfringens associated hepatitis (CPH), and from healthy broilers. All strains, regardless of origin, proved inherently susceptible to ampicillin, narasin, avilamycin, erythromycin and vancomycin. A low frequency of resistance to virginiamycin and bacitracin was also found. Resistance to tetracycline was found in strains isolated in all three countries; Sweden (76%), Denmark (10%) and Norway (29%). In 80% of the tetracycline-resistant isolates, the two resistance genes tetA(P) and tetB(P) were amplified by PCR whereas in 20% only the tetA(P) gene was detected. No tetM gene amplicon was obtained from any of the tetracycline-resistant isolates. The uniform susceptibility to narasin revealed in this study shows that the substance can still be used to control clostridiosis. In this study, C. perfringens also showed a low degree of resistance to most other antimicrobials tested. Despite the small amounts of tetracycline used in poultry, a considerable degree of resistance to tetracycline was found in C. perfringens isolates from Swedish broilers.     

Escherichia coli O157 prevalence in Dutch poultry, pig finishing and veal herds and risk factors in Dutch veal herds

In the period October 1996 through December 2000, a total of 7163 pooled faecal samples of laying hen and broiler flocks, finishing-pig herds and veal herds were examined for the presence of Salmonella spp., Campylobacter spp. and verocytotoxin-producing Escherichia coli O157 as part of a national monitoring programme in The Netherlands. Isolates were tested for eae and VT genes. Risk factors for Dutch veal herds were quantified. For all herd/flock types, faecal samples were cultured for E. coli O157. Of broiler flocks, laying flocks and finishing pig herds, respectively, 1.7%, 0.5% and 0.4% were E. coli O157 positive. In total, 42 of the 454 veal herds (9.3%) showed at least one positive pooled sample. E. coli O157-positive herds were compared (with logistic regression) to negative herds, regarding variables obtained from the questionnaire taken from the farm manager. To account for season, a sine function was included in the logistic regression as offset variable. In the final model, 'pink-veal production' (compared to white-veal production), 'group housing of the sampled herd' (compared to individual housing), 'more than one stable present' (compared to one stable present), 'hygienic measures regarding visitors' (compared to no hygienic measures), 'interval arrival-sampling of a herd of >20 weeks' (compared to < or =10 weeks), and 'presence of other farms within 1 km' (compared to no presence of farms <1 km) showed associations (P<0.05) with the presence of E. coli O157. These results need careful interpretation; they should be considered as indications for further (experimental or cohort-based) research rather then causal associations.     

Clostridium difficile infection in humans and animals, differences and similarities

Clostridium difficile is well known as the most common cause of nosocomial infections in human patients. In recent years a change in epidemiology towards an increase in incidence and severity of disease, not only inside the hospital, but also in the community, is reported. C. difficile is increasingly recognized in veterinary medicine as well and is now considered the most important cause of neonatal diarrhea in swine in North America. Research on the presence of C. difficile in production and companion animals revealed a huge overlap with strains implicated in human C. difficile infection (CDI). This has lead to the concern that interspecies transmission of this bacterium occurs. In this review C. difficile infections in humans and animals are compared. The pathogenesis, clinical signs, diagnosis and prevalence of CDI are described and similarities and differences of CDI between humans and animals are discussed.     

Epidemiology and quality assurance: applications at farm level

Animal production is relevant with respect to farm income and the position of the sector in the market, but also with respect to the quality and safety of products of animal origin, related to public health. Animal production is part of a chain of food production. Therefore, producers have to take consumer expectations and demands in the domains of animal health, welfare and environment into account. A different attitude for production has to be adopted; this attitude can be visualized in good farming practice, GFP, codes. Farmers who focused on quality in its broadest sense need a system supporting them in their management and control of quality risks. Generally speaking, there are three systems for that purpose: GFP, ISO and HACCP. When the hypothesis followed relates to animal health being a feature of quality, or else welfare and environmental issues, then animal health care can be executed following quality control principles. The HACCP concept is well suited for quality control at farm level, involving risk identification and risk management. The on-farm monitoring and surveillance system of critical control points in the animal production process is the most important tool in this procedure. Principles for HACCP application as well as certification fitness of HACCP are elaborated upon. They are illustrated by using salmonellosis in meat-pig farms as objective for an HACCP approach. It is further discussed that, in addition to animal health and quality, animal welfare and environmental issues could also be covered by an HACCP-like system in an integrated manner. Ultimately, the HACCP modules could end up in an overall ISO certification.     

艰难梭菌毒素致病机理的研究进展

艰难梭菌是一种革兰氏阳性厌氧芽胞梭菌,是人类肠道感染的主要致病菌,其主要致病因素为毒素A(肠毒素)和毒素B(细胞毒素).毒素A引发细胞损伤后,毒素B即可侵入肠黏膜,引起细胞病变,导致一系列与感染相关的临床表现.同时,艰难梭菌毒素也是引起猪、鸡等畜禽发生腹泻的重要因素,因此探讨艰难梭菌毒素对机体的损伤作用,有利于揭示艰难梭菌的致病机理,为其防控提供理论依据.     

Epidemiology of Cryptosporidium spp. and Giardia duodenalis on a dairy farm.

Prevalences of Cryptosporidium spp. and Giardia duodenalis in relation to age and season were investigated on a dairy farm in The Netherlands over the course of 1year. The whole herd was sampled five times, whereas calves younger than about 2 months were sampled every 2-3 weeks. Associations between diarrhoea and presence of one or more pathogens (Cryptosporidium spp., G. duodenalis, rotavirus) were investigated. Potential transmission routes of Cryptosporidium spp. were evaluated and positive samples of Cryptosporidium spp. and G. duodenalis were identified to genotype level by PCR microsatellite identification and fingerprinting. Shedding of Cryptosporidium spp. was found in all age categories but peaked in calves 1-3 weeks old (39.1%). Herd prevalence of shedding for Cryptosporidium spp. varied from 2.4% in June to 22.2% in December. Shedding of G. duodenalis was found in all age categories but peaked in animals 4-5 months old (54.5%). Herd prevalence of shedding for G. duodenalis varied from 0.8% in June to 15.5% in February. Cryptosporidium spp. and rotavirus appeared to be significantly associated with diarrhoea in calves. Microsatellite analysis showed two different subtypes (C3 and C1) of Cryptosporidium parvum calf strains. Two genotypes of G. duodenalis were found, one positive by A lineage specific PCR and thus closely related to human genotypes and one genotype, which was negative by A and B lineage specific PCR. The results indicate that cow-to-calf and indirect calf-to-calf transmission both are important routes for acquiring infection with Cryptosporidium spp.