Genomic epidemiology of third-generation cephalosporin-resistant Escherichia coli from Argentinian pig and dairy farms reveals animal-specific patterns of co-resistance and resistance mechanisms.

Control measures are being introduced globally to reduce the prevalence of antibiotic resistance (ABR) in bacteria on farms. However, little is known about the current prevalence and molecular ecology of ABR in bacterial species with the potential to be key opportunistic human pathogens, such as Escherichia coli, on South American farms. Working with 30 dairy cattle farms and 40 pig farms across two provinces in central-eastern Argentina, we report a comprehensive genomic analysis of third-generation cephalosporin-resistant (3GC-R) E. coli, which were recovered from 34.8% (cattle) and 47.8% (pigs) of samples from fecally contaminated sites. Phylogenetic analysis revealed substantial diversity suggestive of long-term horizontal and vertical transmission of 3GC-R mechanisms. CTX-M-15 and CTX-M-2 were more often produced by isolates from dairy farms, while CTX-M-8 and CMY-2 and co-carriage of amoxicillin/clavulanate resistance and florfenicol resistance were more common in isolates from pig farms. This suggests different selective pressures for antibiotic use in these two animal types. We identified the ß-lactamase gene blaROB, which has previously only been reported in the family Pasteurellaceae, in 3GC-R E. coli. blaROB was found alongside a novel florfenicol resistance gene, ydhC, also mobilized from a pig pathogen as part of a new composite transposon. As the first comprehensive genomic survey of 3GC-R E. coli in Argentina, these data set a baseline from which to measure the effects of interventions aimed at reducing on-farm ABR and provide an opportunity to investigate the zoonotic transmission of resistant bacteria in this region. IMPORTANCE: Little is known about the ecology of critically important antibiotic resistance among bacteria with the potential to be opportunistic human pathogens (e.g., Escherichia coli) on South American farms. By studying 70 pig and dairy cattle farms in central-eastern Argentina, we identified that third-generation cephalosporin resistance (3GC-R) in E. coli was mediated by mechanisms seen more often in certain species and that 3GC-R pig E. coli were more likely to be co-resistant to florfenicol and amoxicillin/clavulanate. This suggests that on-farm antibiotic usage is key to selecting the types of E. coli present on these farms. 3GC-R E. coli and 3GC-R plasmids were diverse, suggestive of long-term circulation in this region. We identified the de novo mobilization of the resistance gene blaROB from pig pathogens into E. coli on a novel mobile genetic element, which shows the importance of surveying poorly studied regions for antibiotic resistance that might impact human health.

Ureaplasma diversum-Ureaplasma sp. alone or concomitantly with Mycoplasma hyopneumoniae in pig lungs with and without pneumonia: A descriptive exploratory study in abattoirs / Presencia de Ureaplasma diversum-Ureaplasma sp. solo o junto con Mycoplasma hyopneumoniae en pulmones de cerdos con y sin neumonía: un estudio exploratorio descriptivo en frigorífico

Abstract Occurrence of Ureaplasma diversum (U. diversum) has been associated with repro-ductive failures in cattle and detected in pigs with and without pneumonia. However, its rolein the porcine respiratory disease complex (PRDC) is unclear. A cross-sectional study was con-ducted in abattoirs, inspecting 280 pig lungs from eight herds. All the lungs were inspected,processed and classified according to the histopathological analysis. Moreover, bronchoalveolarlavage (BAL) specimens were collected and processed by PCR for detection of U. diversum andMycoplasma hyopneumoniae (M. hyopneumoniae). Ureaplasma sp.---U. diversum and M. hyop-neumoniae were detected in 17.1% and 29.3% of the analyzed BAL specimens, respectively. Theconcomitant presence of both microorganisms was detected in 12.5% of the inspected lungs.Both agents were found in lungs with and without pneumonia. M. hyopneumoniae was detectedin 31.8% of pig lungs with enzootic pneumonia-like lesions, while Ureaplasma sp.---U. diversumwas detected in 27.5% of lungs with these lesions. This descriptive exploratory study providesinformation for future experimental and field-based studies to better define the pathogenicrole of this organism within the PRDC.

Resumen La presencia de Ureaplasma diversum se ha asociado a fallas reproductivas en el ganado bovino y se ha detectado en cerdos con y sin neumonía. Sin embargo, su participación en el complejo de enfermedades respiratorias porcinas (CERP) no es clara. Se llevó a cabo un estudio transversal en matadero, inspeccionando 280 pulmones de cerdo provenientes de ocho piaras. Todos los pulmones fueron inspeccionados, procesados y clasificados según el análisis histopatológico. También se colectaron muestras de lavado broncoalveolar (LBA) y se procesaron mediante PCR para la detección de U. diversum y Mycoplasma hyopneumoniae. Ureaplasma sp.-U. diversum y M. hyopneumoniae se detectaron en el 17,1% y en el 29,3% de los LBA analizados, respectivamente. La presencia concomitante de ambos microorganismos se detectó en el 12,5% de los pulmones inspeccionados. Ambos agentes se encontraron en pulmones con y sin neumonía. M. hyopneumoniae se detectó en el 31,8% de los pulmones con lesiones compatibles con neumonía enzoótica, mientras que Ureaplasma sp.-U. diversum se detectó en el 27,5% de los pulmones con estas lesiones. Este estudio exploratorio descriptivo proporciona información para futuros estudios experimentales y de campo tendentes a definir mejor el papel patógeno de este organismo dentro del CERP.

In-feed nutritional additive probiotic Saccharomyces boulardii RC009 can substitute for prophylactic antibiotics and improve the production and health of weaning pigs.

Background and Aims: Non-therapeutic antibiotic use is associated with the current decrease in antibiotic therapeutic efficiency and the emergence of a wide range of resistant strains, which constitutes a public health risk. This study aimed to evaluate the use of Saccharomyces cerevisiae var. boulardii RC009 as a nutritional feed additive to substitute the prophylactic use of antibiotics and improve the productive performance and health of post-weaning piglets. Materials and Methods: Four regular nutritional phases were prepared. Post-weaning pigs (21-70 days old) received one of two dietary treatments: T1-basal diet (BD-control group) with in-feed antibiotics as a prophylactic medication (one pulse of Tiamulin in P3 and one pulse of Amoxicillin in P4); and T2-BD without in-feed antibiotics but with Saccharomyces boulardii RC009 (1 × 1012 colony forming unit/T feed). The feed conversion ratio (FCR), total weight gain (TWG-kg), and daily weight gain (DWG-kg) were determined. A post-weaning growth index (GI) was calculated and animals (160 days old) from each treatment were analyzed at the abattoir after sacrifice for carcass weight and respiratory tract lesions. Results: Pigs consuming probiotics had higher TWG and DWG than the control group. The group of animals with low body weight obtained the same results. Saccharomyces boulardii administration decreased diarrhea, and FCR reduction was related to a GI improvement. A significant increase in carcass weight and muscle thickness reduction was observed in animals received the probiotic post-weaning. Conclusion: Saccharomyces boulardii RC009, a probiotic additive, was found to improve the production parameters of pigs post-weaning and enhance their health status, indicating that it may be a promising alternative to prophylactic antibiotics.

Ureaplasma diversum-Ureaplasma sp. alone or concomitantly with Mycoplasma hyopneumoniae in pig lungs with and without pneumonia: A descriptive exploratory study in abattoirs.

Occurrence of Ureaplasma diversum (U. diversum) has been associated with reproductive failures in cattle and detected in pigs with and without pneumonia. However, its role in the porcine respiratory disease complex (PRDC) is unclear. A cross-sectional study was conducted in abattoirs, inspecting 280 pig lungs from eight herds. All the lungs were inspected, processed and classified according to the histopathological analysis. Moreover, bronchoalveolar lavage (BAL) specimens were collected and processed by PCR for detection of U. diversum and Mycoplasma hyopneumoniae (M. hyopneumoniae). Ureaplasma sp.-U. diversum and M. hyopneumoniae were detected in 17.1% and 29.3% of the analyzed BAL specimens, respectively. The concomitant presence of both microorganisms was detected in 12.5% of the inspected lungs. Both agents were found in lungs with and without pneumonia. M. hyopneumoniae was detected in 31.8% of pig lungs with enzootic pneumonia-like lesions, while Ureaplasma sp.-U. diversum was detected in 27.5% of lungs with these lesions. This descriptive exploratory study provides information for future experimental and field-based studies to better define the pathogenic role of this organism within the PRDC.

Antibiotic resistance and associated resistance determinants in different Salmonella enterica serovars isolated from pigs in Argentina.

Background and Aim: Salmonellosis is one of the most common foodborne diseases in the world, and the increasing antibiotic resistance in Salmonella enterica subsp. enterica recovered from food animals constitutes an important risk from a One Health approach. This study aimed to characterize antibiotic resistance and some of its associated resistance determinants in different S. enterica serovars isolated from pigs in Argentina. Materials and Methods: A retrospective study was conducted on Salmonella strains isolated between 2011 and 2015 from pigs in the Pampean region of Argentina. The antimicrobial susceptibility patterns to 21 antimicrobials and some antibiotic resistance determinants were characterized in 55 Salmonella isolates, representing 58 farms. Results: We identified 56% (n=30) of the strains as multidrug-resistant, where resistance to tetracycline (62%, n=34), ampicillin (53%, n=29), nalidixic acid (53%, n=29), chloramphenicol (33%, n=18), and trimethoprim-sulfamethoxazole (31%, n=17) was most common. The wide range of resistance to ampicillin correlates with the presence of TEM type ß-lactamases in the strains. However, high susceptibility was found in the new generation of ß-lactams. Fluoroquinolone resistance is a major concern. Most strains with decreased susceptibility to ciprofloxacin showed gyrA mutations and plasmid-mediated quinolone resistance gene qnrB. Conclusion: Here, we identified broad resistance to some antibiotics frequently used in human therapeutics and several easily transferable resistance mechanisms that could endanger public health.

Identification and distribution of Brachyspira species in feces from finishing pigs in Argentina.

BACKGROUND AND AIM: Brachyspira are Gram-negative, aerotolerant spirochetes that colonize the large intestine of various species of domestic animals and humans. The aim of this study was to determine the presence and distribution of different species of Brachyspira presents in feces from finishing pigs in Argentina. MATERIALS AND METHODS: Fecal samples (n=1550) were collected from finishing pigs in 53 farms of the most important swine production areas of Argentina, and Brachyspiras species were identified by bacteriological and molecular methods. RESULTS: The regional prevalence of Brachyspira spp. was at the level of 75.5% (confidence interval 95%, 62.9-87.9), and it was lower among those farms with >1001 sows. One hundred and twenty-eight isolates of Brachyspira were properly identified and the species found were: Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira innocens, and Brachyspira murdochii. B. hyodysenteriae and B. pilosicoli had low prevalence (1.9% and 7.5%, respectively), B. innocens was isolated from 34% of the farms and B. murdochii was found in 39.6%. CONCLUSION: The present study provides epidemiological data about herd prevalence of the different Brachyspira species in Argentina, showing that the prevalence figure seems to be higher than that reported in other countries.

Ureaplasma diversum and Ureaplasma sp. in nasal cavity of pigs: Distribution among herds and individual frequency based on pooled samples.

The role of Ureaplasma diversum in the porcine respiratory disease complex (PRDC), its circulation among herds and prevalence in live pigs is unknown; thus, the objectives of this study were: to determine the presence of U. diversum in indoor intensive pig herds and to determine the individual frequency of pigs with U. diversum from pooled samples. A cross sectional study was carried out in 16 indoor intensive herds from Córdoba and La Pampa provinces, collecting eight nasal swabs specimens that were further processed by two pools of four specimens each by a PCR targeting a fragment of 16S ribosomal RNA gene. Four PCR products were sequenced and aligned against data bases. U. diversum - Ureaplasma sp. were detected in 56.3% of the analyzed herds, with 16.5% (95% CI 8.2-30.8) of positive pigs. It was concluded that U. diversum - Ureaplasma sp. are present in the nasal cavity of live pigs, being widely distributed among herds.

Effect of soybean expeller supplementation during the final phase of sow gestation on litter birth weight.

AIM: Nutrition plays a key role in the production of pigs, especially in pregnant sows, where modifications in nutritional requirements can affect their productive performance. The aim of this study was to evaluate nutritional supplementation with soybean expeller in sows during the last third of the gestation period and its effect on litter birth weight. MATERIALS AND METHODS: A quasi-experimental study was conducted on a farrow-to-finish farm, where 192 sows were equally assigned to treatment and control groups. Several variables were recorded at both the sow and piglet level. The treatment group consisted of piglets from 95 sows supplemented with soybean expeller during the final phase of gestation (20 days), and the comparison group consisted of piglets from 97 sows fed only with a commercial balanced ration (control group). RESULTS: Soybean expeller supplementation increased individual piglet weight by 190-270 g, and the increased number of live piglets could decrease the weight of each piglet. Moreover, the number of piglets weighing <900 g decreased by 10% as compared to the control group, indicating that supplementation could improve pre-weaning mortality. CONCLUSION: Our results suggest that soybean expeller supplementation in sows during the last third of the gestation period could improve production performance, especially on organic farms.

Assessment of a segregated medicated early weaning protocol for elimination of Actinobacillus pleuropneumoniae / Avaliação de um protocolo de desmame precoce segregado medicado para a eliminação de Actinobacillus pleuropneumoniae

ABSTRACT: To assess the success of a segregated medicated early weaning protocol for elimination of Actinobacillus pleuropneumoniae, ten consecutive batches of 100 pigs per batch weaned at 7-9 days of age were monitored at 21-22 weeks of age looking for presence of productive cough, presence of antibodies against the agent and pleuropneumonia-compatible lung lesions at slaughter. Also, whole tonsils were processed for A. pleuropneumoniae identification by both bacteriological isolation and nested-PCR using a direct method. Positive serological test (1.4%) and PCR (3.5%) results, suggested that A. pleuropneumoniae could not be eradicated in all batches, even using segregated medicated early weaning protocol.

RESUMO: Para avaliar o sucesso de um protocolo de desmame precoce segregado medicado para a eliminação de Actinobacillus pleuropneumoniae, dez lotes consecutivos de 100 suínos por lote desmamados aos 7-9 dias de idade foram monitorados às 21-22 semanas de idade procurando a presença de tosse produtiva, presença de anticorpos contra o agente e lesões pulmonares compatíveis com pleuropneumonia no abate. Além disso, as tonsilas inteiras foram processadas para a identificação de A. pleuropneumoniae por isolamento bacteriológico e nested PCR usando um método direto. Os resultados serológicos (1,4%) e PCR (3,5%) positivos sugerem que não foi possível erradicar em todos os lotes, mesmo usando um protocolo de desmame precoce segregado medicado.

Monitoramento da presença de Mycoplasma hyopneumoniae em granjas de suínos durante a implementação de programas de erradicação / Monitoring the presence of Mycoplasma hyopneumoniae in swine farms during the implementation of eradication programs

O objetivo deste estudo foi monitorar a presença de M. hyopneumoniae em granjas suínas durante a implementação de programas de erradicação utilizando diferentes técnicas de diagnóstico focalizando no PCR. Trabalhou-se com uma empresa que possuía três granjas, uma parto-terminação (390 matrizes), uma múltiplo-sítio (4100 matrizes) e uma nova granja que povoava suas novas instalações. Nas duas primeiras, foi desenvolvido um programa de despovoamento parcial para erradicar a pneumonia enzoótica suína, a última foi povoada pelos suínos dos anteriores após a erradicação. Nos três rebanhos, os suínos foram monitorados por: sorologia (ELISA), PCR, lesões pulmonares macro e microscópicas e a presença de tosse não produtiva. A ausência de tosse, a baixa porcentagem de suínos soropositivos na fase de terminação e a baixa proporção de lesões pulmonares no abate sugerem que a pneumonia enzoótica suína foi erradicada, mas não o agente causativo -M. hyopneumoniae- cujo DNA foi detectado pela PCR, mostrando diferentes comportamentos de acordo com o rebanho.

The aim of this study was to monitor the presence of M. hyopneumoniae in pig farms during the implementation of eradication programs using different diagnostic techniques focusing on PCR. They worked with a company owner of three farms, a farrow-to-finish (390 sows), a multiple-site (4100 sows) and a new one that was populated its new facility. In the first two were developed a partial depopulation program to eradicate swine enzootic pneumonia, the latter one was populated with pigs after the previous eradication. In the three farms, the pigs were monitored by: serology (ELISA), PCR, macroscopic and microscopic lung lesions and the presence of non-productive cough. The absence of cough, low percentage of seropositive pigs in the finishing stage and the low proportion of lung lesions at slaughter suggest that swine enzootic pneumonia was eradicated, but not the causative agent -M. hyopneumoniae- whose DNA was detected by PCR showing different behaviors according to the herd.

Respuestas de anticuerpos pasivosy efecto de la edad de los lechonesen la vacunación contra el virusde la peste porcina clásica / Passive antibodies response and effect of the age of the swine on the vaccination against classical swine fever virus

La vacunación con la cepa China es utilizada para prevenir la Peste Porcina Clásica. Pero la presencia de anticuerpos pasivos y la edad de los lechones a la vacunación pueden originar una respuesta humoral activa no satisfactoria. Se vacunaron animales de 7, 21 y 56 días de edad con y sin inmunidad pasiva. Se tomaron muestra de sangre al momento de la vacunación y a los 15 y 45 días posteriores. Los animales respondieron de distintas maneras a la vacunación, según la presencia o no de anticuerpos pasivos. Se observó que a mayor edad de vacunación, mayor era el porcentaje de animales que respondieron a la vacuna en el último muestreo. La técnica de ELISA no permitió detectar anticuerpos a los 15 días de vacunados.

The vaccination with the Chinese strain is used to prevent the Classical Swine Fever. But the presence of passive antibodies and age of piglets at the time of vaccination can originate an unsatisfactory active humoral response. In this study 7, 21 and 56 days animals with and without passive immunity, were vaccinated. Blood samples were taken at the time of vaccination and then at 15 and 45 days later. The animals responded in different ways to vaccination, according to the presence or not of passive antibodies. It was observed that as greater the age of vaccination, greater was the percentage of animals that responded to the vaccine in the last sampling. The ELISA technique did not allow detecting antibodies 15 days after vaccination.

Evolución de lesiones podales en lechones lactantes / Evolution of injuries in the limbs of suckling piglets

En un estudio de pseudocohortes se inspeccionaron los miembros craneales y caudales de 3142 lechones lactantes de 5 a 27 días de vida, para evaluar prevalencia de lesiones y su evolución, clasificándolas por edad y región anatómica. El trabajo se desarrolló en un establecimiento porcino de crianza intensiva, de ciclo completo, todo adentro-todo afuera, con 1200 madres totales y un promedio de 50 partos semanales, con una edad de destete promedio de 24 días. De los 3142 lechones, 249 (7.92%) no presentaron lesiones, en los restantes 2893 (92.8%) se observaron 8415 lesiones, correspondiendo 3869 (46%) a fibrosis, 4314 (51.20%) a heridas y 232 (2.8%) a artritis. De ese total 5165 (61.4%) correspondieron a los carpos, 737 (8.8%) a los tarsos y 2513 (29.9%) a las pezuñas. En lechones de 5-9 días de edad las heridas representaron el 73.8% del total de lesiones, las que tuvieron dos formas de evolución, hacia la fibrosis o la artritis. Esta evolución de las heridas mayormente tiende a la fibrosis en el carpo y a la artritis en el tarso. Se concluye que los miembros de lechones en maternidad presentan alta prevalencia de lesiones bilaterales desde la edad temprana y principalmente en los miembros craneales.

The purpose of this work was to study the prevalence, evolution and type of lesions occurring in the front and back legs of 3142 suckling piglets from 5 to 27 days of age, also classifying ithem according to age and anatomical region. From the total 3142 piglets, 249 (7.92%) did not have any visible lesions. In the other 2893 (92.08%) piglets, a total of 8415 different lesions were observed. Over this total, an amount of 3869 (46%) piglets showed fibrosis, 4314 (51.20%) had different type of injuries and 232(2.8%) presented arthritis. Over the total of 8415 lesions, 5165 (61.4%), 737 (80.8%), and 2513 (29.9%) had lesions on the carpus, tarsus and hoofs, respectively. Injuries represented 73.8% of the total lesions in 5 to 9 days old piglets, which evolved either towards fibrosis or arthritis. Fibrosis was the product of evolution on lesions mainly in the carpus, whereas arthritis evolved mainly in the tarsus.

Síndrome multisistémico de desmejoramiento posdestete (SMDP) en cerdos criados al aire libre en una granja situada en Argentina / Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs reared in an outdoor system in the farm in Argentina

Se realizó un estudio clínico-patológico en cerdos criados al aire libre, estos presentaron signos de desmejoramiento y muerte entre los 40 a 90 días de vida. Durante un periodo determinado se registraronlos índices de mortalidad en las categorías de recría y levante. A un grupo de animales con signos de desmejoramiento se les extrajo sangre y se les realizó la necropsia. Se tomaron muestras de tejidos para la realización de análisis histopatológicos, inmunohistoquímicos, bacteriológicos, parasicológicos y virológicos. Los índices de mortalidad estuvieron incrementados en la primera parte del período estudiado. Los signos clínicos observados fueron: retardo en el crecimiento, pérdida de peso y muerte. A la necropsia se observó palidez de mucosas, ganglios linfáticos megálicos y friables, edema de pericardio y de cavidad abdominal. En pulmón se observó neumonía intersticial. El riñón se mostró con áreas blanquecinas en corteza y edema en pelvis. Las lesiones observadas microscópicamente fueron: depleción linfocitaria en órganos linfoides, infiltración de histiocitos, presencia de células gigantes, cuerpos de inclusión intra citoplasmáticos y necrosis multifocales. Además, tanto las células gigantes, los cuerpos de inclusión y los macrófagos de las áreas foliculares de los tejidos linfoides, se manifestaron como inmunorreactivos en la técnica del complejo abidina biotina (ABC) frente al anticuerpo monoclonal del circovirus porcino tipo II (CVP2). Estos hallazgos confirman la presencia de Síndrome de Multisistémico de Desmejoramiento Posdestete (SMDP) en cerdos criados al aire librecon cuadros clínicos patológicos similares a los descriptos en sistemas confinados.