Martín Talavera-Rojas

ERIC-PCR Genotyping of Emergent Serovar C-1 Isolates of Avibacterium paragallinarum from Mexico

SUMMARY. Between 2008 and 2010, 14 isolates of Avibacterium paragallinarum were identified as serovar C-1 in Mexico. All isolates were obtained from commercial laying hens suffering infectious coryza despite a history of vaccination. The enterobacterial repetitive intergenic consensus-based PCR genotyping showed that all isolates had a common pattern. Until recently, serovars A-1, A-2, B-1, and C-2 were the serovars prevalent in Mexico. Serovar C-1 has been identified in Japan and recently in the Americas in Ecuador. Our current study suggests that Av. paragallinarum serovar C-1 is an emerging serovar in Mexico. Our results also indicate that the Mexican isolates of Av. paragallinarum serovar C-1 may have a clonal relationship. Knowledge of the genetic diversity of Av. paragallinarum may be of value in understanding vaccine performance and identifying the best combination to achieve broader protection.

Phylogenetic Relationship of Serovar C-1 Isolates of Avibacterium paragallinarum

SUMMARY The bacterium Avibacterium paragallinarum is the etiologic agent of infectious coryza of chickens. Serovar C-1 has emerged in infectious coryza outbreaks in layer hens of Ecuador and Mexico. In the current study, genotyping and phylogenetic analyses of five Ecuadorian and 10 Mexican isolates of Av. paragallinarum serovar C-1 were performed. All 15 isolates share a unique enterobacterial repetitive intergenic consensus-based-PCR fingerprint and have identical 16S ribosomal RNA and hemagglutinin antigen gene sequences. Results indicate that Ecuadorian and Mexican isolates of serovar C-1 of Av. paragallinarum have a clonal relationship. RESUMEN Nota de Investigación—Relación filogenética de aislamientos de Avibacterium paragallinarum serovar C-1. La bacteria Avibacterium paragallinarum es el agente etiológico de la coriza infecciosa de los pollos. El serovar C-1 se ha presentado en brotes de coriza infecciosa en gallinas ponedoras de Ecuador y de México. En el presente estudio, se llevó a cabo la genotipificación y análisis filogenéticos de cinco aislamientos ecuatorianos y de diez aislamientos mexicanos de Av. paragallinarum serovar C-1. Los 15 aislamientos compartieron una huella genética intergénica, consensuada y repetitiva única de enterobacterias, que fue detectada por PCR y también mostraron secuencias idénticas de los genes ribosomal 16S y del antígeno de la hemaglutinina. Los resultados indican que los aislamientos ecuatorianos y mexicanos de serovar C-1 de Av. paragallinarum tienen una relación clonal.

Virulence of serovar C-1 strains of Avibacterium paragallinarum

SUMMARY The bacterium Avibacterium paragallinarum is the etiologic agent of infectious coryza of chickens. There are nine serovars of A. paragallinarum, and serovar C-1 has emerged in outbreaks of infectious coryza in layer hens in the Americas, with all isolates having been obtained from infectious coryza-vaccinated chickens. In the current study, the clinical and histopathologic outcomes of experimental infections in chickens with A. paragallinarum of serovar C-1 were investigated. The Japanese serovar reference strain, H-18, and a Mexican isolate, ESV-135, were included in the study. No differences in clinical sign scores or morbidity were observed between the two strains. The two bacterial strains caused microscopic lesions of lymphoplasmacytic inflammation in the mucosa of the nasal cavity, infraorbital sinus, and trachea. Similar severe lesions were observed in birds inoculated with both H-18 and ESV-135 strains. The lesions were present 48 hr after inoculation and persisted until day 10 after inoculation. Slight to severe, extensive hemorrhages were observed in the lumen, mucous membranes, and lamina propria of the nasal cavity and infraorbital sinus in most of the chickens inoculated with either the reference strain H-18 or the ESV-135 isolate. Hemorrhages in the upper respiratory tract of chickens experimentally infected with A. paragallinarum are reported here for the first time. The results have confirmed the high virulence of the reference strain H-18 as previously reported and have shown that the Mexican isolate was as virulent as the reference strain. The virulence of A. paragallinarum isolates may play a role in explaining why severe infectious coryza outbreaks are being seen in both vaccinated and nonvaccinated chicken flocks.

Serotyping, Genotyping, and Antimicrobial Susceptibility of Ornithobacterium rhinotracheale Isolates from Mexico.

SUMMARY The bacterium Ornithobacterium rhinotracheale is associated with respiratory disease and septicemia in poultry. In this study, 9 reference strains and a total of 23 isolates of O. rhinotracheale from respiratory diseased poultry from Mexico were serotyped and genotyped. Furthermore, the antimicrobial susceptibility of isolates and reference strains of O. rhinotracheale were determined. All isolates belong to serotype A and showed a clonal relationship. All reference strains and isolates were resistant to colistin, fosfomycin, gentamicin, kanamycin, streptomycin, and trimethoprim–sulfamethoxazole. These results should eventually be helpful in planning strategies for the control of O. rhinotracheale infections in poultry in Mexico.

Genetic characterization of Escherichia coli isolated from cattle carcasses and feces in Mexico state.

Meat of bovine origin is one of the major vehicles in the transmission of verotoxigenic Escherichia coli (VTEC) to human consumers. This pathogen can produce serious human illness, including bloody diarrhea and hemolytic uremic syndrome. The aim of the current study was to characterize E. coli isolates (mainly VTEC strains) belonging to several serotypes in samples from cattle carcasses and feces of three municipal slaughter plants from Mexico State. The genetic diversity and molecular relatedness among the isolates was evaluated with multiple-locus variable-number tandem repeat analysis (MLVA). To our knowledge, and with the exception of E. coli O157:H7, this is the first time that serotypes analyzed here have been subtyped by MLVA in Mexico. MLVA typing grouped the 37 strains from this study into 30 distinct genotypes, 26 of which were unique. These findings indicate that cattle carcasses and feces from slaughter plants in Mexico are a source of VTEC that are genetically diverse in terms of serotypes and virulence profiles. The presence of these pathogens in carcasses indicates the high probability of the spread of VTEC strains during slaughter and processing.

Phenotypic and genotypic profile of clinical and animal multidrug-resistant Salmonella enterica isolates from Mexico

The objective of this study was to obtain a phenotypic and genotypic profile of Salmonella enterica including multidrug‐resistant (MDR) isolates from food‐producing animals and clinical isolates, as well as their genetic relatedness in two different States of Mexico (Jalisco and State of Mexico).

Distribution of lymphocytes, immunoglobulin-containing cells, macrophages, and dendritic cells in the accessory sex glands of rams experimentally infected with Actinobacillus seminis

A distribuicao das celulas envolvidas na resposta imune em glândulas sexuais acessorias de carneiros experimentalmente infectados com Actinobacillus seminis foi estudada. Doze carneiros de um ano de idade foram experimentalmente infectados via intrauretral (IU) (n=4) e via intraepididimal (IE) (n=4) e quatro animais controles (CON) foram utilizados. Os animais foram abatidos 35 dias apos a inoculacao, amostras foram retiradas das glândulas sexuais acessorias e testes bacteriologicos e histopatologicos foram realizados. A presenca de linfocitos CD4, CD8 e TCRγδ (WC1), celulas CD45RO, macrofagos (CD14), celulas dendriticas (CD1b) e celulas contendo IgA, IgG and IgM (IgCC) foi determinada. Os animais do grupo IE desenvolveram epididimite clinica. Nao foram visualizadas lesoes nos carneiros do grupo IU, dois dos CON inoculados intraepididimalmente desenvolveram pequenas lesoes no epididimo. Isolados de A. seminis foram obtidos de 6:16 (37,5%) nas glândulas sexuais acessorias no grupo IE mas nao nos grupos IU e CON. No grupo CON celulas contendo IgA and IgM predominaram nas glândulas bulbouretrais e na prostata e foram escassas ou ausentes nas vesiculas e na ampola. Um incremento significativo de celulas contendo IgA, IgG and IgM foi confirmado nas vesiculas seminais, na ampola e nas glândulas bulbouretrais no grupo IE. Nos grupos IE e IU foi evidenciado um aumento em CD4, CD8, WC1, CD45RO e CD14 nas vesiculas e ampola. As celulas dendriticas CD1b estavam presentes na ampola e nas vesiculas com processo inflamatorio. A. seminis induziu uma resposta imune local nos grupos IE e IU. Estes resultados indicam um padrao diferente de celulas imunes infiltrantes nas glândulas sexuais acessorias de carneiros infectados por A. seminis.

Protection Conferred by Infectious Coryza Vaccines Against Emergent Avibacterium paragallinarum Serovar C-1

SUMMARY Infectious coryza is an upper respiratory disease of chickens caused by Avibacterium paragallinarum. Outbreaks of infectious coryza caused by Av. paragallinarum serovar C-1 isolates in coryza-vaccinated flocks in Ecuador and Mexico have been reported. In the current study, the protection conferred by four commercially available, trivalent infectious coryza vaccines in chickens challenged with a serovar C-1 isolate from an apparent coryza vaccine failure in a layer flock in Mexico was evaluated. Only one infectious coryza vaccine provided a good protection level (83%) in vaccinated chickens. These results might explain the infectious coryza outbreaks in vaccinated flocks that have been observed in the field. RESUMEN Nota de Investigación- Protección conferida por vacunas de coriza infecciosa contra la serovaridad emergente C-1 de Avibacterium paragallinarum. La coriza infecciosa es una enfermedad del tracto respiratorio superior de los pollos causada por Avibacterium paragallinarum. Se han reportado brotes de coriza infecciosa causada por A. paragallinarum serovar C-1 aislados de parvadas vacunadas contra coriza en Ecuador y en México. En este estudio se evaluó la protección conferida por cuatro, vacunas trivalentes disponibles comercialmente contra la coriza infecciosa, en pollos desafiados con la serovariedad C-1 aislada de un brote aparentemente asociado con una falla vacunal en aves ponedoras en México. Sólo una vacuna contra la coriza infecciosa proporcionó un buen nivel de protección (83%) en los pollos vacunados. Estos resultados podrían explicar los brotes de coriza infecciosa en las aves vacunadas que han sido observados en el campo.