Serovars, Virulence and Antimicrobial Resistance Genes of Non-Typhoidal Salmonella Strains from Dairy Systems in Mexico.

Salmonella isolated from dairy farms has a significant effect on animal health and productivity. Different serogroups of Salmonella affect both human and bovine cattle causing illness in both reservoirs. Dairy cows and calves can be silent Salmonella shedders, increasing the possibility of dispensing Salmonella within the farm. The aim of this study was to determine the genomic characteristics of Salmonella isolates from dairy farms and to detect the presence of virulence and antimicrobial resistance genes. A total of 377 samples were collected in a cross-sectional study from calves, periparturient cow feces, and maternity beds in 55 dairy farms from the states of Aguascalientes, Baja California, Chihuahua, Coahuila, Durango, Mexico, Guanajuato, Hidalgo, Jalisco, Queretaro, San Luis Potosi, Tlaxcala, and Zacatecas. Twenty Salmonella isolates were selected as representative strains for whole genome sequencing. The serological classification of the strains was able to assign groups to only 12 isolates, but with only 5 of those being consistent with the genomic serotyping. The most prevalent serovar was Salmonella Montevideo followed by Salmonella Meleagridis. All isolates presented the chromosomal aac(6')-Iaa gene that confers resistance to aminoglycosides. The antibiotic resistance genes qnrB19, qnrA1, sul2, aph(6)-Id, aph(3)-ld, dfrA1, tetA, tetC, flor2, sul1_15, mph(A), aadA2, blaCARB, and qacE were identified. Ten pathogenicity islands were identified, and the most prevalent plasmid was Col(pHAD28). The main source of Salmonella enterica is the maternity areas, where periparturient shedders are contaminants and perpetuate the pathogen within the dairy in manure, sand, and concrete surfaces. This study demonstrated the necessity of implementing One Health control actions to diminish the prevalence of antimicrobial resistant and virulent pathogens including Salmonella.

Hygiene and restraint of pigs is associated with absence of Taenia solium cysticercosis in a rural community of Mexico

Objetivo. Determinar la prevalencia y factores de riesgo asociados con cisticercosis porcina en una población rural de Veracruz, México. Material y métodos. Se diagnosticó cisticercosis porcina por medio de palpación lingual y anticuerpos circulantes en cerdos de traspatio en 178 casas. Se analizaron los factores de riesgo mediante una encuesta a los dueños respecto a las condiciones de crianza de los cerdos y sus características demográficas. Resultados. Los 53 cerdos estudiados fueron negativos al metacéstodo de Taenia solium por palpación lingual y para la presencia de anticuerpos contra este agente por inmunoelectrotransferencia. El 91 poir ciento de las casas contaban con letrinas y los cerdos estaban confinados en zonas restringidas. Conclusiones. Este estudio muestra que el confinamiento de cerdos puede explicar la ausencia de Taenia solium en comunidades rurales, y sugiere que es factible y práctico establecer medidas de intervención. El texto completo en inglés de este artículo también está disponible en: http://www.insp.mx/salud/index.html