The Impact of Overstocking and Negative Energy Balance on Quantitative Measurement of Non-typhoidal Salmonella in Periparturient Dairy Cattle

Stressful conditions in animal production facilities may exacerbate the fecal shedding and foodborne transmission of non-typhoidal Salmonella enterica subsp. enterica. Dairy cows are reservoirs of this zoonotic microorganism, and its prevalence has roughly doubled in the past decade on dairy farms in United States. Dairy cows are commonly overstocked at the feed bunk, and stressors placed on the animal prior to parturition may exacerbate Salmonella shedding. However, no studies have evaluated the impact of overstocking and metabolic stress on fecal concentrations of the pathogen. Therefore, we conducted a field trial with 120 multiparous dairy cows randomized into one of four treatment groups with different stocking densities at the feed bunk during the periparturient period as follows: US, understocked from -60 to -1 DRC; OS, overstocked from -60 to -1 DRC; USOS, understocked from -60 to -26 DRC/overstocked from -25 to -1 DRC; and OSUS, overstocked from -60 to -26 DRC/ understocked from -25 to -1 DRC. Fecal and blood samples were collected at four time points relative to calving. qPCR assays were used to quantify Salmonella invA gene and total bacterial community from fecal samples, and a subset of isolates recovered from fecal bacterial culture were characterized using pulsed field gel electrophoresis and serotyping. Serum non-esterified fatty acids (NEFA) were measured as a metabolic stress indicator using an immunoassay. Multivariable analyses were performed to test if changes in Salmonella concentrations were associated with stocking density, energy balance, or days relative to calving. From fecal isolates, three Salmonella serovars were identified, S. Cerro; Kentucky; Meleagridis. Concentrations of Salmonella increased as cows approached calving. Higher stocking densities at the feed bunk did not impact total bacterial community or NEFA; however, cows in the overstocked groups had higher Salmonella fecal concentrations. Further, cows with higher NEFA concentrations after calving had a higher likelihood of detection of Salmonella. Future farm interventions should aim to reduce environmental and metabolic stress during the periparturient period to decrease the dissemination of Salmonella to cattle, the environment, and humans.Peer reviewe

Estandardização de um protocolo de caraterização molecular para a identificação de espécie de cepas terrestres do gênero brucella

La brucelosis es la enfermedad zoonótica más extendida en el mundo que afecta diversos animales, incluyendo especies domésticas y de vida silvestre. Es causada por una bacteria perteneciente al género Brucella, el cual incluye nueve especies distintas e infectantes de mamíferos terrestres y marinos. Cada especie de Brucella presenta variaciones en la secuencia de ADN que afectan a los nucleótidos en una posición específica del genoma. A estas variaciones se les llama polimorfismo. El polimorfismo de las especies de Brucella localizado en los genes que codifican para las proteínas glk, omp25ytrpE, se utilizó para desarrollar un ensayo múltiple basado en la extensión de cebadores, el cual permite identificar un aislamiento como miembro de una de las nueve especies reconocidas. Los métodos tradicionales para la identificación de Brucella a nivel de especie consumen mucho tiempo y ponen en riesgo al personal laboratorial. Es por ello que la finalidad de este trabajo es evitar la ambigüedad, agilizar el procedimiento, disminuir el tiempo de respuesta y generar una herramienta laboratorial más efectiva para mejorar la vigilancia epidemiológica, el diagnóstico y el abordaje de la brucelosis en Costa Rica. El siguiente trabajo presenta la estandarización del protocolo para la extracción de ADN de Brucella, así como de una serie de amplificaciones de fragmentos de genes de interés por medio de la reacción en cadena de la polimerasa (PCR) y la estandarización de la reacción de extensión de cebadores.Brucellosis is the most widespread zoonotic disease worldwide that affects various animals, including domestic species and wildlife. It is caused by bacteria belonging to the genus Brucella, which includes nine different species and infective terrestrial and marine mammals. Each species of Brucella has variations in DNA sequence involving nucleotides in a specific position in the genome. These variations are called polymorphisms The polymorphism of Brucella species located in the genes coding for proteins glk, omp25, and trpE was used to develop a multiplex assay based on primer extension, with which it can identify an isolate as a member of nine recognized species. Traditional methods for identification of Brucella at the species level, time consuming and endanger laboratory staff. That is why the aim of this work is to avoid ambiguity, to streamline the procedure, reduce the response time and generate a more effective laboratory tool for improving epidemiological surveillance, diagnosis and approach of brucellosis in Costa Rica. This paper presents the standardization of the protocol for DNA extraction of Brucella, the standardization of a series of amplifications of fragments of genes of interest through the chain reaction (PCR) and standardization of the extension reaction primers.Brucelose é a doença zoonótica mais distribuída por todo o mundo e que afeta várias espécies animais incluindo espécies domésticas e selvagens. É causada por uma bactéria pertencente ao género Brucella que inclui nove espécies diferentes e é infectante para mamíferos terrestres e marinhos. Cada espécie de Brucella tem variações na sequência de DNA envolvendo os nucleótidos de uma posição especifica do genoma. Estas variações são chamadas polimorfismos. O polimorfismo das espécies de Brucella localizado no código genético para proteínas glk, omp25 e trpE foi utilizado para desenvolver um ensaio múltiplo baseado na primeira extensão, com a qual se pode identificar e isolar como membro de uma das 9 espécies. Os métodos tradicionais para identificação de Brucella ao nível da espécie, consomem muito tempo e põe em risco o pessoal de laboratório. É por isso que o objectivo deste trabalho é evitar a ambiguidade, agilizar o procedimento, reduzir o tempo de resposta e gerar uma ferramenta laboratorial mais efectiva para melhorar a vigilância epidemiológica, diagnostico e aproximação à brucelose na Costa Rica. Este artigo, apresenta a estandardização do protocolo para extracção de DNA de Brucella, estandardização de uma série de amplificações de fragementos genéticos de interesse através da reacção de polimerase em cadeia (PCR) e estandardização da reacção dos primers de extensão.Universidad Nacional, Costa RicaEscuela de Medicina Veterinari

Impact of clinical salmonellosis in veal calves on the recovery of salmonella in lymph nodes at harvest

The objective of this study was to determine the prevalence, serotypes, antimicrobial resistance phenotypes, and pulsed-field gel electrophoresis (PFGE) patterns of Salmonella recovered in feces and mesenteric and prefemoral lymph nodes (LNs) from cohorts of calves with and without a confirmed outbreak of salmonellosis. In a prospective cohort study, 160 calves from four farms without a reported outbreak (nonoutbreak farms) were sampled at farm and harvest. In addition, harvest samples from 80 calves of two farms with a confirmed outbreak (outbreak farms) were collected. A culture protocol for Salmonella isolation was applied for all samples and recovered isolates were further characterized by serotyping, antimicrobial susceptibility testing, and PFGE. Among nonoutbreak farms, Salmonella was recovered from 0% (0/160) farm fecal samples, 3.7% (6/160) harvest fecal swabs, 21.9% (35/160) mesenteric LNs, and 0.6% (1/160) prefemoral LNs. Serotypes identified in nonoutbreak herds included Salmonella Typhimurium, Cerro, Hartford, and Newport. Most isolates (64.3%, 27/42) exhibited a unique multidrug-resistant (MDR) phenotype, including resistance to extended-spectrum cephalosporins. Salmonella prevalence in harvest fecal samples and prefemoral LNs among calves from outbreak farms was numerically higher, but not significantly different than those without an outbreak. Serotypes recovered from outbreak farms included Salmonella Heidelberg and Typhimurium, and the monophasic Salmonella Typhimurium strains 4,5,12:i:- and 4,12:i:-, which have been also reported as highly pathogenic in humans. All isolates (33/33) exhibited an MDR phenotype. Salmonella strains recovered from ill calves in two outbreaks had indistinguishable PFGE patterns, suggesting between-farm transmission. In addition, the genotype of Salmonella Heidelberg causing an outbreak among calves was recovered from three prefemoral LNs of surviving members of the cohort at harvest. Implementation of preharvest biosecurity measures (limited personnel and visitor traffic, vehicle, footwear, and utensils disinfection) should be highly recommended to decrease the prevalence of Salmonella on farms and safeguard the food safety.El objetivo de este estudio era determinar la prevalencia, los serotipos, los fenotipos de resistencia a los antimicrobianos y los patrones de electroforesis en gel de campo pulsado (PFGE) de la Salmonella recuperada en las heces y los ganglios linfáticos mesentéricos y prefemorales (LN) de cohortes de terneros con y sin brote confirmado de salmonelosis. En un estudio de cohorte prospectivo, se tomaron muestras de 160 terneros de cuatro explotaciones sin brote notificado (explotaciones sin brote) en la explotación y en la cosecha. Además, se recogieron muestras de cosecha de 80 terneros de dos explotaciones con un brote confirmado (explotaciones con brotes). Se aplicó un protocolo de cultivo para el aislamiento de Salmonella en todas las muestras y los aislados recuperados se caracterizaron además por serotipificación, pruebas de susceptibilidad antimicrobiana y PFGE. En las explotaciones que no sufrieron brotes, se recuperó Salmonella en el 0% (0/160) de las muestras fecales de la explotación, en el 3,7% (6/160) de los hisopos fecales de la cosecha, en el 21,9% (35/160) de los LN mesentéricos y en el 0,6% (1/160) de los LN prefemorales. Los serotipos identificados en los rebaños sin brotes incluían Salmonella Typhimurium, Cerro, Hartford y Newport. La mayoría de los aislados (64,3%, 27/42) presentaban un fenotipo único multirresistente (MDR), incluida la resistencia a las cefalosporinas de espectro extendido. La prevalencia de Salmonella en las muestras fecales de la cosecha y en los LNs prefemorales entre los terneros de las granjas con brotes fue numéricamente más alta, pero no significativamente diferente a la de aquellos sin brotes. Los serotipos recuperados en las explotaciones con brotes incluían Salmonella Heidelberg y Typhimurium, y las cepas monofásicas de Salmonella Typhimurium 4,5,12:i:- y 4,12:i:-, que también han sido notificadas como altamente patógenas en humanos. Todos los aislados (33/33) presentaban un fenotipo MDR. Las cepas de Salmonella recuperadas de terneros enfermos en dos brotes presentaban patrones de PFGE indistintos, lo que sugiere una transmisión entre granjas. Además, el genotipo de Salmonella Heidelberg que causó un brote entre los terneros se recuperó de tres LN prefemorales de miembros supervivientes de la cohorte en la cosecha. La aplicación de medidas de bioseguridad antes de la cosecha (limitación del tráfico de personal y visitantes, desinfección de vehículos, calzado y utensilios) debería ser muy recomendable para disminuir la prevalencia de Salmonella en las explotaciones y salvaguardar la seguridad alimentaria.Escuela de Medicina Veterinari

High prevalence of multidrug-resistant community-acquired methicillin-resistant staphylococcus aureus at the largest veterinary teaching hospital in Costa Rica

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen associated with severe infections in companion animals present in the community, and it is diagnosed in animals admitted to veterinary hospitals. However, reports that describe the circulation of MRSA in animal populations and veterinary settings in Latin America are scarce. Therefore, the objective of this study was to determine the prevalence and investigate the molecular epidemiology of MRSA in the environment of the largest veterinary teaching hospital in Costa Rica. Preselected contact surfaces were sampled twice within a 6-week period. Antimicrobial resistance, SCCmec type, Panton-Valentine leukocidin screening, USA type, and clonality were assessed in all recovered isolates. Overall, MRSA was isolated from 26.5% (27/102) of the surfaces sampled, with doors, desks, and examination tables most frequently contaminated. Molecular analysis demonstrated a variety of surfaces from different sections of the hospital contaminated by three highly related clones/pulsotypes. All, but one of the isolates were characterized as multidrug-resistant SCCmec type IV-USA700, a strain sporadically described in other countries and often classified as community acquired. The detection and frequency of this unique strain in this veterinary setting suggest Costa Rica has a distinctive MRSA ecology when compared with other countries/regions. The high level of environmental contamination highlights the necessity to establish and enforce standard cleaning and disinfection protocols to minimize further spread of this pathogen and reduce the risk of nosocomial and/or occupational transmission of MRSA.El Staphylococcus aureus resistente a la meticilina (MRSA siglas en ingles) es un patógeno asociado a infecciones graves en animales de compañía animales de compañía presentes en la comunidad, y se diagnostica en animales ingresados en hospitales veterinarios. Sin embargo, los informes que describan la circulación de MRSA en poblaciones animales y entornos veterinarios en América Latina son escasos. Por lo tanto, el objetivo de este estudio fue determinar la prevalencia e investigar la epidemiología molecular del MRSA en el entorno del mayor hospital universitario veterinario de Costa Rica. Las superficies de contacto preseleccionadas se tomaron muestras dos veces en un período de 6 semanas. Se analizó la resistencia a los antimicrobianos, el tipo de SCCmec, la leucocidina Panton-Valentine y clonalidad en todos los aislados recuperados. En general, el MRSA se aisló de 26,5% (27/102) de las superficies muestreadas, siendo las puertas, los escritorios y las mesas de examen las más frecuentemente contaminadas. El análisis molecular demostró una variedad de superficies de diferentes secciones del hospital contaminadas por tres clones/pulsos altamente relacionados. Todos los aislados, excepto uno, se caracterizaron como SCCmec tipo IV-USA700, una cepa descrita esporádicamente en otros países y a menudo clasificada como adquirida en la comunidad. La detección y la frecuencia de esta cepa única en este entorno veterinario sugieren que Costa Rica tiene una ecología distintiva de MRSA en comparación con otros países. ecología del MRSA en comparación con otros países/regiones. El alto nivel de contaminación ambiental La alta contaminación ambiental subraya la necesidad de establecer y aplicar protocolos de limpieza y desinfección estándar para minimizar la minimizar la propagación de este patógeno y reducir el riesgo de transmisión nosocomial y/o laboral del MRSA.Escuela de Medicina Veterinari

First Report of Campylobacter hepaticus Isolation in Laying Hens and Broiler Breeders with Spotty Liver Disease in Costa Rica

Poultry producers in Costa Rica have informally reported a spotty liver disease–like syndrome for more than 20 yr. However, despite many attempts, the infectious agent responsible for this syndrome had not been identified. Therefore, following current knowledge of spotty liver disease diagnosis, we invited veterinarians and poultry producers to submit samples to the diagnostic laboratories of the Veterinary Medicine School, Universidad Nacional, to identify the infectious agent of this syndrome. Veterinarians and poultry producers were instructed to collect gallbladders and livers aseptically and send them for pathology examinations and bacterial cultures in less than 24 hr after collection. Samples were processed for standard histopathologic studies and cultured under aerophilic, anaerobic, and microaerophilic conditions. Campylobacter-like colonies were isolated and identified by biochemical and PCR tests. Here we report for the first time the isolation, biochemical characterization, and molecular confirmation of Campylobacter hepaticus in laying hens and broiler breeders with spotty liver disease in Costa Rica.Nota de investigación- Primer reporte de aislamiento de Campylobacter hepaticus en gallinas de postura y reproductoras pesadas con necrosis hepática focal en Costa Rica. Los productores avícolas en Costa Rica han reportado extraoficialmente un síndrome similar a la necrosis hepática focal durante más de 20 años. Sin embargo, a pesar de muchos intentos, el agente infeccioso responsable de este síndrome no había sido identificado. Por ello, siguiendo los conocimientos actuales relacionados con la necrosis hepática focal, se invito a los veterinarios y a los productores avícolas a enviar muestras a los laboratorios de diagnostico de la Escuela de Medicina Veterinaria de la Universidad Nacional, para identificar el agente infeccioso de este síndrome. Se instruyo a los veterinarios y productores avícolas para recolectar vesículas biliares e hígados asepticamente y enviarlos para exámenes patologicos y para cultivos bacterianos en menos de 24 horas despues de la recolección. Las muestras se procesaron para estudios histopatológicos estándar y se cultivaron en condiciones aerofilas, anaeróbicas y microaerófilas. Las colonias sugestivas de Campylobacter se aislaron e identificaron mediante pruebas bioquímicas y por PCR. Aquí se reporta por primera vez el aislamiento, caracterización bioquímica y confirmacion molecular de Campylobacter hepaticus en gallinas de postura y reproductoras pesadas con la necrosis hepática focal en Costa Rica.Universidad Nacional, Costa RicaEscuela de Medicina Veterinari

Temporal trends in antimicrobial resistance of fecal Escherichia coli from deer

The changing epidemiologic role of wildlife as reservoirs of antimicrobial-resistant bacteria (ARB) is poorly understood. In this study, we characterize the phenotypic resistance of commensal Escherichia coli from fecal samples of 879 individual white-tailed (Odocoileus virginianus; WTD) over a ten-year period and analyze resistance patterns. Our results show commensal E. coli from WTD had significant linear increases in reduced susceptibility to 5 of 12 antimicrobials, including broad-spectrum cephalosporins and fluoroquinolones, from 2006 to 2016. In addition, the relative frequency distribution of minimal inhibitory concentrations of two additional antimicrobials shifted towards higher values from across the study period. The prevalence of multidrug-resistant commensal E. coli increased over the study period with a prevalence of 0%, 2.2%, and 3.7% in 2006, 2012, and 2016, respectively. WTD may be persistently and increasingly exposed to antibiotics or their residues, ARB, and/or antimicrobial resistance genes via contaminated environments like surface water receiving treated wastewater effluent.El papel epidemiológico cambiante de la fauna silvestre como reservorio de bacterias resistentes a los antimicrobianos (ARB) es se conoce poco. En este estudio, caracterizamos la resistencia fenotípica de Escherichia coli comensal de fecales de 879 ejemplares de cola blanca (Odocoileus virginianus; WTD) durante un periodo de diez años y analizamos patrones de resistencia. Nuestros resultados muestran que la E. coli comensal de WTD tuvo aumentos lineales significativos en la reducción de la susceptibilidad a 5 de 12 antimicrobianos, incluyendo cefalosporinas de amplio espectro y fluoroquinolonas, desde 2006 a 2016. Además, la distribución de la frecuencia relativa de las concentraciones inhibitorias mínimas de dos antimicrobianos adicionales se desplazó hacia valores más altos a lo largo del periodo de estudio. La prevalencia de E. coli comensal multirresistente aumentó a lo largo del periodo de estudio con una prevalencia del 0%, 2,2% y 3,7% en 2006, 2012 y 2016, respectivamente. Los WTD pueden estar expuestos de forma persistente y creciente a los antibióticos o a sus residuos, ARB, y/o genes de resistencia antimicrobiana a través de entornos contaminados como las aguas superficiales que reciben efluentes de aguas residuales tratadas.Escuela de Medicina Veterinari

Achados post-mortem e caracterização bacteriana da salmonelose septicêmica equina: Descrição de um caso.

Se describe el primer caso, debidamente confirmado, de salmonelosis en un equino en Costa Rica; una potra iberoamericana de siete meses de edad con un cuadro de diarrea de unas cuatro semanas de transcurso y baja condición corporal. Se confirmó la presencia de Salmonella entérica, subespecie entérica, mediante el estudio bacteriológico de muestras de heces. En el estudio post-mortem, se observó una tiflocolitis ulcerativa y necrotizante extensiva severa.The first duly confirmed case of equine salmonellosis in Costa Rica is described, a seven-month-old Ibero-American filly with a four-week-long case of diarrhea and poor body condition. The presence of Salmonella enterica subspecies enterica was confirmed through a bacteriological study of stool samples. In the post-mortem study, severe extensive ulcerative and necrotizing typhlocolitis was observed.Universidad Nacional, Costa RicaEscuela de Medicina Veterinari

The Impact of Overstocking and Negative Energy Balance on Quantitative Measurement of Non-typhoidal Salmonella in Periparturient Dairy Cattle

Stressful conditions in animal production facilities may exacerbate the fecal shedding and foodborne transmission of non-typhoidal Salmonella enterica subsp. enterica. Dairy cows are reservoirs of this zoonotic microorganism, and its prevalence has roughly doubled in the past decade on dairy farms in United States. Dairy cows are commonly overstocked at the feed bunk, and stressors placed on the animal prior to parturition may exacerbate Salmonella shedding. However, no studies have evaluated the impact of overstocking and metabolic stress on fecal concentrations of the pathogen. Therefore, we conducted a field trial with 120 multiparous dairy cows randomized into one of four treatment groups with different stocking densities at the feed bunk during the periparturient period as follows: US, understocked from -60 to -1 DRC; OS, overstocked from -60 to -1 DRC; USOS, understocked from -60 to -26 DRC/overstocked from -25 to -1 DRC; and OSUS, overstocked from -60 to -26 DRC/ understocked from -25 to -1 DRC. Fecal and blood samples were collected at four time points relative to calving. qPCR assays were used to quantify Salmonella invA gene and total bacterial community from fecal samples, and a subset of isolates recovered from fecal bacterial culture were characterized using pulsed field gel electrophoresis and serotyping. Serum non-esterified fatty acids (NEFA) were measured as a metabolic stress indicator using an immunoassay. Multivariable analyses were performed to test if changes in Salmonella concentrations were associated with stocking density, energy balance, or days relative to calving. From fecal isolates, three Salmonella serovars were identified, S. Cerro; Kentucky; Meleagridis. Concentrations of Salmonella increased as cows approached calving. Higher stocking densities at the feed bunk did not impact total bacterial community or NEFA; however, cows in the overstocked groups had higher Salmonella fecal concentrations. Further, cows with higher NEFA concentrations after calving had a higher likelihood of detection of Salmonella. Future farm interventions should aim to reduce environmental and metabolic stress during the periparturient period to decrease the dissemination of Salmonella to cattle, the environment, and humans.Peer reviewe

Antimicrobial resistance and genetic diversity of Campylobacter spp. isolated from broiler chicken at three levels of the poultry production chain in Costa Rica

This research was supported by the Universidad Nacional, Costa Rica, as part of FIDA project 054541-0000, entitled “Prevalencia, caracterización molecular y perfil de resistencia a antibióticos de Campylobacter spp. en pollo para consumo humano de Costa Rica.” The contributions from the personnel at the Bacteriology Laboratory, Escuela de Medicina Veterinaria, Universidad Nacional, and the National Reference Centre for Microbiological Food Safety of Costa Rican Institute for Research and Education in Nutrition and Health during the sample processing are highly appreciated.Campylobacter spp. are considered the most common bacterial cause of human gastroenteritis, one of the four main causes of diarrheal disease worldwide, and they are one of the main foodborne pathogens causing hospitalizations and deaths. Here, 148 strains of Campylobacter spp. isolated from poultry at farms, processing plants, and retail stores in Costa Rica were examined for resistance to six antibiotics. An agar dilution test was used to determine the MIC and susceptibility profiles against doxycycline, ciprofloxacin, nalidixic acid, enrofloxacin, chloramphenicol, and erythromycin. In addition, a pulsed-field gel electrophoresis analysis was carried out to determine the genotype relatedness of a representative subset of the isolates. Approximately 136 (92%) of the 148 analyzed isolates showed resistance to the tested drugs. Nalidixic acid, ciprofloxacin, and enrofloxacin were the antibiotics for which resistance occurred most frequently (91.2, 85.8, and 85.8%, respectively); followed by doxycycline (25.0%), chloramphenicol (5.4%), and erythromycin (2.7%). The profile conferring only resistance to quinolones was the most frequently found, and only 2.0% of the isolates showed resistance to quinolones and macrolides simultaneously. Results showed a high frequency of resistant Campylobacter spp. strains and evidenced the distribution, selection, and circulation of resistant strains along the poultry chain from farms to consumers. Cross-contamination and resistance seem to play important roles in the dissemination of these strains at specific points of the poultry chain, even when control measures are being taken. The establishment of effective surveillance and control strategies represents an essential tool for foodborne diseases mitigation. The rational use of antibiotics, especially those still showing efficacy, should be a priority in both human and veterinary medicine to contain the progress of this phenomenon and its consequences.Campylobacter spp. se considera la causa bacteriana más común de gastroenteritis humana, una de las cuatro principales causas de enfermedad diarreica en todo el mundo, y es uno de los principales patógenos transmitidos por los alimentos que causan hospitalizaciones y muertes. En este trabajo se examinaron 148 cepas de Campylobacter spp. aisladas de aves de corral en granjas, plantas de procesamiento y tiendas minoristas de Costa Rica para determinar su resistencia a seis antibióticos. Se utilizó una prueba de dilución en agar para determinar la CIM y los perfiles de susceptibilidad a la doxiciclina, la ciprofloxacina, el ácido nalidíxico, la enrofloxacina, el cloranfenicol y la eritromicina. Además, se llevó a cabo un análisis de electroforesis en gel de campo pulsado para determinar el parentesco genotípico de un subconjunto representativo de los aislados. Aproximadamente 136 (92%) de los 148 aislados analizados mostraron resistencia a los fármacos probados. El ácido nalidíxico, la ciprofloxacina y la enrofloxacina fueron los antibióticos a los que se presentó resistencia con mayor frecuencia (91,2, 85,8 y 85,8%, respectivamente), seguidos de la doxiciclina (25,0%), el cloranfenicol (5,4%) y la eritromicina (2,7%). El perfil que confiere sólo resistencia a las quinolonas fue el más frecuente, y sólo el 2,0% de los aislados mostraron resistencia a las quinolonas y los macrólidos simultáneamente. Los resultados mostraron una elevada frecuencia de cepas resistentes de Campylobacter spp. y evidenciaron la distribución, selección y circulación de cepas resistentes a lo largo de la cadena avícola, desde las granjas hasta los consumidores. La contaminación cruzada y la resistencia parecen desempeñar un papel importante en la diseminación de estas cepas en puntos específicos de la cadena avícola, incluso cuando se toman medidas de control. El establecimiento de estrategias eficaces de vigilancia y control representa una herramienta esencial para la mitigación de las enfermedades transmitidas por los alimentos. El uso racional de los antibióticos, sobre todo de los que aún muestran su eficacia, debería ser una prioridad tanto en medicina humana como veterinaria para contener el avance de este fenómeno y sus consecuencias.Escuela de Medicina Veterinari