Emergence of fluoroquinolone resistance in the native Campylobacter coli population of pigs exposed to enrofloxacin

Objective: The effect of a single 5 day enrofloxacin treatment on the native Campylobacter coli population in conventionally weaned 5-week-old pigs was investigated. Materials: Twelve pigs were split into two groups of six: one group was treated with a therapeutic dose (15 mg/pig/day) of enrofloxacin and the other remained untreated to act as the control. Campylobacter coli were isolated from faecal samples and tested for ciprofloxacin resistance by measuring MIC values. Mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene of resistant isolates were identified by sequencing and denaturing HPLC. Levels of enrofloxacin and its primary metabolite ciprofloxacin in the pig faeces were also measured by HPLC. Results: No quinolone-resistant C. coli (n = 867) were detected in any of the pigs prior to treatment, indicating <0.1% resistance in the group. Resistant C. coli were isolated from pigs for up to 35 days after treatment with a therapeutic dose. These resistant C. coli had MIC values of 128 mg/L and 8-16 mg/L for nalidixic acid and ciprofloxacin, respectively, and the same single point mutation causing a Thr-86 to Ile substitution in the QRDR was identified in each. The concentration of enrofloxacin in the pig faeces was 2-4 mug/g faeces for the duration of the 5 day therapeutic treatment and was detected up to 10 days post-treatment. Ciprofloxacin was also measured and peaked at 0.6 mug/g faeces in the treated group. Conclusion: This study provides evidence that a single course of enrofloxacin treatment contributes directly to the emergence and persistence of fluoroquinolone resistance in C. coli.

A defined intestinal colonization microbiota for gnotobiotic pigs

Maximising the ability of piglets to survive exposure to pathogens is essential to reduce early piglet mortality, an important factor in efficient commercial pig production. Mortality rates can be influenced by many factors, including early colonization by microbial commensals. Here we describe the development of an intestinal microbiota, the Bristol microbiota, for use in gnotobiotic pigs and its influence on synthesis of systemic immunoglobulins. Such a microbiota will be of value in studies of the consequences of early microbial colonization on development of the intestinal immune system and subsequent susceptibility to disease. Gnotobiotic pig studies lack a well-established intestinal microbiota. The use of the Altered Schaedler Flora (ASF), a murine intestinal microbiota, to colonize the intestines of Caesarean-derived, gnotobiotic pigs prior to gut closure, resulted in unreliable colonization with most (but not all) strains of the ASF. Subsequently, a novel, simpler porcine microbiota was developed. The novel microbiota reliably colonized the length of the intestinal tract when administered to gnotobiotic piglets. No health problems were observed, and the novel microbiota induced a systemic increase in serum immunoglobulins, in particular IgA and IgM. The Bristol microbiota will be of value for highly controlled, reproducible experiments of the consequences of early microbial colonization on susceptibility to disease in neonatal piglets, and as a biomedical model for the impact of microbial colonization on development of the intestinal mucosa and immune system in neonates.

Expression of cyclooxygenase-2 in intestine of pigs of different ages and hygiene status

Prostaglandins (PG) are bioactive lipids derived from the metabolism of membrane polyunsaturated fatty acids (PUFA), and play important roles in a number of biological processes including cell division, immune responses and wound healing. Cyclooxygenase (COX) is the key enzyme in PG synthesis from arachidonic acid. The hypothesis of the present study was that expression of COX-2 in porcine intestine was dependent on the microbial load and the age of piglets. Piglets were obtained from sows raised either on outdoor free-range farms or on indoor commercial farms, and littermates were divided into three treatments: One group of piglets suckled the sow, a second group was put into an isolator and fed a milk formula, and a third group was put into the isolator fed milk formula and injected with broad spectrum antibiotics. Samples were collected from the 75% level of the small intestine at day 5, 28 and 56 of age. Tissue section from four piglets from each of these six treatment groups was analysed by immunofluorescence for COX-2 and type-IV collagen (basement membrane, defining lamina propria (LP)). Image analysis was used to determine the number of positive pixels expressing LP and epithelial COX-2. COX-2 expressing cells were observed in LP and epithelium in all porcine intestinal samples. When analysing images obtained on day 28, injection of antibiotics seemed to reduce the COX-2 expression in intestinal samples of piglets when compared to other treatments (P=0.053). No significant effect of farm, treatments or age of piglets was observed on COX-2 expressing data when analysing all data of images obtained at day 28 and 56. By double-labelling experiments, COX-2 was found not to be expressed on cell co-expressing CD45, CD16, CD163 or CD2, thus indicating that mucosal leukocytes, including dendritic cells, macrophages and NK cells did not express COX-2. Future research should investigate the role of COX-2 expression in the digestive tract in relation to pig health.

A pig’s microbiota – a result of many factors

Piglets can be reared under a variety of conditions ranging from outdoor, organic farms to high intensity, indoor facilities which use prophylactic antibiotics and everything in between. Do these different early-life influences matter when it comes to longer-term health and productivity?

Serological response of guinea pigs to oily and aqueous inactivated vaccines containing a Brazilian isolate of the Bovine Viral Diarrhea Virus (BVDV)

Bovine Viral Diarrhea Virus (BVDV) is widespread in cattle in Brazil and research shows its large antigenic variability. Available vaccines are produced with virus strains isolated in other countries and may not be effective. In this study, inactivated vaccines containing the Brazilian BVDV-Ib IBSP11 isolate were developed and tested on 6 groups of 10 guinea pigs (Cavia porcellus). Animals in groups A and C received an aqueous vaccine (aluminum hydroxide); B and D groups received an oily vaccine (Montanide ISA50); Group E positive-control animals were given an imported commercial vaccine with BVDV-la Singer; Group F animals were sham vaccinated (negative control). Groups A, B and E received two doses, and Groups C and D, three, every 21 days. Twelve blood samples were taken, at 21-day intervals over 231 days, and evaluated for antibody titer through virus-neutralization (VN), using a homologous strain (IBSP11), and a heterologous strain (BVDV-la NADL). Most animals, 42 days following the first dose, seroconverted to both strains and, after the second dose, there was a significant increase of titers in all groups. The oily formulation induced greater response after the third administration. This increase was not observed with the aqueous vaccines, regardless of the virus used in the VN. Antibody decline was more rapid in animals that received aqueous vaccines. The results showed the importance of studying the influence of endemic strains of commercial vaccines, to improve the efficacy of BVD vaccination. Use of the endemic strain in vaccine formulation presented promising results, as well as the use of guinea pigs as a laboratory model. (C) 2011 Elsevier Ltd. All rights reserved.

Marxist Comrades or Capitalist Pigs? : From Musical Proletarians to Musical Capitalists in Roddy Doyle's The Commitments

Marxist themes of Roddy Doyle’s The Commitments have not often been looked at. Yet, they are decidedly prominent. The band make use of a Marxist image and of collectivist easy-played, easily-understood music in order to gain working class listeners. In fact, the band itself is based on an egalitarian structure, until it, due to an increasing individualist wish for success, falls apart. The aim of this essay is thus to argue, through pointing to the Marxist rhetoric of the band and the hypocrisy around it, and through a comparative reading between The Commitments and Orwell’s Animal Farm, that The Commitments has an allegorical value, much like Animal Farm does, when it comes to depicting the way Marxism has worked and failed as it has been practised in reality.

Genetic Control of Residual Variance for Teat Number in Pigs

The genetic improvement in litter size in pigs has been substantial during the last 10-15 years. The number of teats on the sow must increase as well to meet the needs of the piglets, because each piglet needs access to its own teat. We applied a genetic heterogeneity model on teat numberin sows, and estimated medium-high heritability for teat number (0.5), but low heritability for residual variance (0.05), indicating that selection for reduced variance might have very limited effect. A numerically positive correlation (0.8) between additive genetic breeding values for mean and for variance was found, but because of the low heritability for residual variance, the variance will increase very slowly with the mean.

Anaerobic biodigestion of pigs feces in the initial, growing and finishing stages fed with diets formulated with corn or sorghum

Objetivou-se avaliar a produção e a qualidade do biogás e do biofertilizante obtidos em biodigestores abastecidos com dejetos de suínos, nas fases inicial, crescimento e terminação, alimentados com dietas formuladas à base de milho ou sorgo. Foram utilizados 20 biodigestores de bancada, com tempo de retenção hidráulica de 30 dias, e cargas diárias que continham 4,0 a 6,0% de sólidos totais (ST) e 3,6 a 5,2% de sólidos voláteis (SV). Nos efluentes dos biodigestores, foram verificados teores médios de ST variando de 1,6 a 2,0% e de SV entre 1,2 e 1,6%. As reduções médias de ST foram de 57,7 a 64,7% e de SV de 61,7 a 69,0%, sendo que houve diferença somente na fase de terminação, na qual as maiores reduções médias foram para biodigestores abastecidos com dejetos de animais alimentados com dietas à base de milho. Nos biodigestores abastecidos com dejetos de animais em fase inicial e de crescimento, alimentados com dietas formuladas à base de milho, foram verificadas maiores produções médias de biogás e os maiores potenciais médios de produção de biogás. Os potenciais médios obtidos foram 0,033; 0,181; 0,685; 0,788 e 1,132 m³ por kg de afluente, estrume, ST adicionados, SV adicionados e SV reduzidos, respectivamente. Não foram verificadas diferenças quanto ao teor médio de metano no biogás entre dietas e fases. As concentrações médias dos nutrientes N, P, K, Ca, Mg, Na, Fe, Mn, Zn e Cu no afluente e efluente dos biodigestores variaram entre as dietas e fases.

Antimicrobial resistance of Salmonella serotypes isolated from slaughter-age pigs and environmental samples

The aim of this study was to determine the antimicrobial resistance patterns of Salmonella strains isolated from slaughter-age pigs and environmental samples collected at modern swine raising facilities in Brazil. Seventeen isolates of six serotypes of Salmonella enterica subsp. enterica were isolated out of 1,026 collected samples: Salmonella Typhimurium (1), Salmonella Agona (5), Salmonella Sandiego (5), Salmonella Rissen (1), Salmonella Senftenberg (4), and Salmonella Javiana (1). Resistance patterns were determined to extended-spectrum penicillin (ampicillin), broad-spectrum cephalosporins (cefotaxime and ceftriaxone), aminoglycosides (streptomycin, neomycin, gentamicin, amikacin, and tobramycin), narrow-spectrum quinolone (nalidixic acid), broad-spectrum quinolone (ciprofloxacin and norfloxacin), tetracycline, trimethoprim, and chloramphenicol. Antimicrobial resistance patterns varied among serotypes, but isolates from a single serotype consistently showed the same resistance profile. All isolates were resistant to tetracycline, streptomycin, and nalidixic acid. One isolate, Salmonella Rissen, was also resistant to cefotaxime and tobramycin. All serotypes were susceptible to ceftriaxone, norfloxacin, ciprofloxacin, ampicillin, gentamicin, and chloramphenicol. The high resistance to tetracycline and streptomycin may be linked to their common use as therapeutic drugs on the tested farms. No relation was seen between nalidixic acid and fluoroquinolone resistance.

Prevalence of pigs infected by Salmonella typhimurium at slaughter after an enterocolitis outbreak

A cross-sectional study was performed to estimate the prevalence of slaughter pigs infected by Salmonella typhimurium after an enterocolitis outbreak in a commercial pig farm, which was characterised by diarrhoea during the growing phase. Anatomopathological and histopathological findings were suggestive of salmonellosis, which was further confirmed by isolation of S. typhimurium from organs and faeces samples from diseased animals. Ileocolic lymph nodes were aseptically collected from 43 pigs during slaughter procedures. The estimated prevalence of Salmonella-infected pigs was 53.48% [confidence interval (CI): 42.94:64.02%]. This finding demonstrates that the carriage of S. typhimurium at slaughter might be high if pigs originate from a batch previously affected by Salmonella-enterocolitis outbreak at the pre-harvest pork production chain. (c) 2005 Elsevier B.V. All rights reserved.

Nose-to-nose transmission of Salmonella Typhimurium between weaned pigs

Little attention has been paid to the possibility of transmission of Salmonella in intensive pig production systems through alternate methods, such as airborne or direct nose-to-nose contact. This experimental study tested the hypothesis of nose-to-nose transmission of Salmonella enterica serovars Typhimurium (Trial I) and Agona (Trial II) in weaned pigs using stainless steel/ glass isolation cabinets. In each trial, cabinet 1 (control pigs) and cabinet 2 (sentinel pigs) were connected directly to the fan unit. Cabinet 3 (seeded pigs) was not directly linked to the fan, but was arranged to receive a constant unidirectional airflow from cabinet 2 (sentinel pigs) through a 10 cm diameter hole, which also allowed nose-to-nose contact between pigs housed in these two cabinets. Air was taken out of the system through ducts connecting cabinets 1 and 3 to the exhauster. Therefore, direct contact among seeded and sentinel pigs was allowed but possible aerial transference of contaminated particles between those cabinets was prevented. The system was opened 21 days post-inoculation and tissue samples were collected for bacteriological analysis. The recovery of nalidixic acid-resistant Salmonella Typhimurium from sentinel pigs corroborates the hypothesis of nose-to-nose transmission of that pathogen in pigs. However, serovar-related differences might exist regarding the nose-to-nose transmissibility of Salmonella in pigs, since Salmonella Agona was not detected in sentinel pigs (Trial II). Published by Elsevier B.V.

First isolation and molecular characterization of Toxoplasma gondii from finishing pigs from São Paulo State, Brazil

Toxoplasma gondii infection is widely prevalent in humans in Brazil. Among the food animals, pigs are considered the most important meat source of T. gondii for infection in humans. In the present study, we report the first isolation of viable T. gondii from finishing pigs in Brazil. Antibodies to T. gondii were found in 49 (17%) of 286 pigs prior slaughter using the modified agglutination test (MAT) at a serum dilution of 1:25. Attempts were made to isolate T. gondii from 28 seropositive pigs. Samples of heart, brain, and tongue from each pig were pooled, digested in acid pepsin, and bioassayed in five mice per pig. Viable T. gondii was isolated from seven pigs; all isolates were lethal for mice. Restriction fragment length polymorphism on products of SAG2 locus amplified by PCR revealed that two isolates were Type I and five were Type III. The results indicate that phenotypically and genetically T. gondii isolates from pigs from Brazil are distinct from isolates of T gondii from pigs in the USA. (c) 2005 Elsevier B.V. All rights reserved.

Use of saprophytic leptospira strains in the serodiagnosis of experimental leptospirosis in guinea-pigs (Cavia sp)

No presente estudo foi avaliada, através da reação de soroaglutinação microscópica, a eficiência de quatro estirpes apatogênicas de Leptospira biflexa (Buenos Aires, Patoc 1, Rufino e São Paulo) como antígeno único para o diagnóstico sorológico em cobaias experimentalmente infectadas com sete diferentes sorotipos de Leptospira interrogans (canicola, grippotyphosa, hardjo, icterohaemorrhagiae, pomona, tarassovi e wolffi). As estirpes Buenos Aires, Patoc 1, Rufino e São Paulo não foram eficientes em revelar títulos de anticorpos nos soros das cobaias infectadas com Leptospira interrogans. Durante o experimento, foi observada a ocorrên cia de reações sorológicas cruzadas entre as estirpes Patoc 1 e São Paulo e também entre os sorotipos wolffi e hardjo.