Genomic surveillance of antimicrobial resistance shows cattle and poultry are a moderate source of multi-drug resistant non-typhoidal Salmonella in Mexico.

Multi-drug resistant (MDR) non-typhoidal Salmonella (NTS) is a public health concern globally. This study reports the phenotypic and genotypic antimicrobial resistance (AMR) profiles of NTS isolates from bovine lymph nodes (n = 48) and ground beef (n = 29). Furthermore, we compared genotypic AMR data of our isolates with those of publicly available NTS genomes from Mexico (n = 2400). The probability of finding MDR isolates was higher in ground beef than in lymph nodes:χ2 = 12.0, P = 0.0005. The most common resistant phenotypes involved tetracycline (40.3%), carbenicillin (26.0%), amoxicillin-clavulanic acid (20.8%), chloramphenicol (19.5%) and trimethoprim-sulfamethoxazole (16.9%), while more than 55% of the isolates showed decreased susceptibility to ciprofloxacin and 26% were MDR. Conversely, resistance to cephalosporins and carbapenems was infrequent (0-9%). MDR phenotypes were strongly associated with NTS serovar (χ2 = 24.5, P<0.0001), with Typhimurium accounting for 40% of MDR strains. Most of these (9/10), carried Salmonella genomic island 1, which harbors a class-1 integron with multiple AMR genes (aadA2, blaCARB-2, floR, sul1, tetG) that confer a penta-resistant phenotype. MDR phenotypes were also associated with mutations in the ramR gene (χ2 = 17.7, P<0.0001). Among public NTS isolates from Mexico, those from cattle and poultry had the highest proportion of MDR genotypes. Our results suggest that attaining significant improvements in AMR meat safety requires the identification and removal (or treatment) of product harboring MDR NTS, instead of screening for Salmonella spp. or for isolates showing resistance to individual antibiotics. In that sense, massive integration of whole genome sequencing (WGS) technologies in AMR surveillance provides the shortest path to accomplish these goals.

Reduction of Salmonella contamination on the surface of chicken skin using bacteriophage.

BACKGROUND: Enteric infections caused by Salmonella spp. remain a major public health burden worldwide. Chickens are known to be a major reservoir for this zoonotic pathogen. The presence of Salmonella in poultry farms and abattoirs is associated with financial costs of treatment and a serious risk to human health. The use of bacteriophages as a biocontrol is one possible intervention by which Salmonella colonization of chickens could be reduced. In a prior study, phages Eϕ151 and Tϕ7 significantly reduced broiler chicken caecal colonization by S. Enteritidis and S. Typhimurium respectively. METHODS: Salmonella-free Ross broiler chickens were orally infected with S. Enteritidis P125109 or S. Typhimurium 4/74. After 7 days of infection, the animals were euthanased, and 25cm2 sections of skin were collected. The skin samples were sprayed with a phage suspension of either Eϕ151 (S. Enteritidis), Tϕ7 phage suspension (S. Typhimurium) or SM buffer (Control). After incubation, the number of surviving Salmonellas was determined by direct plating and Most Probable Number (MPN). To determine the rate of reduction of Salmonella numbers on the skin surface, a bioluminescent S. Typhimurium DT104 strain was cultured, spread on sections of chicken breast skin, and after spraying with a Tϕ11 phage suspension, skin samples were monitored using photon counting for up to 24 h. RESULTS: The median levels of Salmonella reduction following phage treatment were 1.38 log10 MPN (Enteritidis) and 1.83 log10 MPN (Typhimurium) per skin section. Treatment reductions were significant when compared with Salmonella recovery from control skin sections treated with buffer (p < 0.0001). Additionally, significant reduction in light intensity was observed within 1 min of phage Tϕ11 spraying onto the skin contaminated with a bioluminescent Salmonella recombinant strain, compared with buffer-treated controls (p < 0.01), implying that some lysis of Salmonella was occurring on the skin surface. CONCLUSIONS: The results of this study suggest that phages may be used on the surface of chicken skin as biocontrol agents against Salmonella infected broiler chicken carcasses. The rate of bioluminescence reduction shown by the recombinant Salmonella strain used supported the hypothesis that at least some of the reduction observed was due to lysis occurred on the skin surface.

Exploratory survey at the mexican marketplace on pork muscles characteristics from USA and Mexico

Trends in variation of physical, chemical and sensory traits due to country of origin (COO) were evaluated for samples from United States of America (U.S.A.) and Mexico of three pork muscles, Rectus femoris (RF, n = 20 from each COO), Vastus medialis (VM, n = 20 from each COO), and Longissimus dorsi (LD, n = 10 from each COO) in two separate, small-scale, exploratory surveys conducted at Mexico City. Compositional, physical and chemical properties and consumer acceptability traits of these Mexican and U.S.A. pork samples were quite similar, though Mexican pork samples generally were more variable. LD samples from U.S.A. had greater (P<0.05) water-holding and emulsifying capacities whereas both RF and LD from U.S.A. required lower shear force (P<0.05) compared to Mexican counterparts. Ratings from consumers did not indicate preference for pork from any of the countries. Because of the limited number of observations for the samples surveyed these results are preliminary and may not adequately characterize the populations of each country, but they did reveal important trends for selected traits of Mexican and U.S.A. pork currently available at the local market.

Se evaluaron tendencias en la variación de características físico-químicas y sensoriales debidas al país de origen (PDO), de muestras mexicanas y estadounidenses (EUA) de tres músculos del cerdo: Rectus femoris (RF, n = 20 por PDO), Vastus medialis (VM, n = 20 por PDO), and Longissimus dorsi (LD, n = 10 por PDO) mediante dos encuestas exploratorias separadas, a baja escala, conducidas en la Ciudad de México. Los resultados mostraron que músculos porcinos de los dos orígenes tienen propiedades físicas, químicas y sensoriales muy similares, aunque las muestras mexicanas mostraron mayor variabilidad. Las muestras de LD de EUA tuvieron mayor (P<0,05) capacidad de retención de agua y emulsificación, y al igual que las de RF, requirieron menos fuerza de corte que las mexicanas (P<0,05). Los consumidores no pudieron detectar diferencias entre muestras de diferente origen. Debido al limitado número de observaciones en las muestras encuestadas, los resultados deben considerarse preliminares y si bien no permiten caracterizar adecuadamente las poblaciones de cada país, las mismas revelan tendencias importantes para los rasgos seleccionados de la carne de cerdo procedente de México y EUA disponibles actualmente en el mercado local.

Detección de resistencia en Haemonchus contortus al sulfóxido de albendazol inyectado mediante la prueba de campo de reducción de huevos en ganado ovino / Resistance detection of Haemonchus contrortus to injectable albendazole sulfoxide using the agg reduction count technique in sheep

El objetivo del presente trabajo fue comparar la eficacia del sulfóxido de albendazol y de levamisol contra H. contortus en ovinos infectados experimentalmente. Se formaron tres grupos homogéneos en cuanto a eliminación de huevos. grupo I (n = 19) fue tratado con sulfóxido de albendazol, grupo II (n = 19) con levamisol, ambos vía intramuscular, a la dosis recomendada por el fabricante. El Grupo III (n = 18) no recibió tratamiento y sirvió como testigo. Se calculó el porcentaje de reducción de huevos en heces (PRH), el intervalo de confianza al 95 por ciento (IC) y el porcentaje de animales positivos (PAP) a los siete y catorce días después del tratamiento (DPT). A los siete DPT, el grupo I tuvo un PRH de 65.9 por ciento (IC = 44 por ciento-79 por ciento) y un PAP = 100 por ciento, mientras que en el grupo II el PRH fue de 99.7 por ciento (IC = 99 por ciento -100 por ciento) y el PAP de 15.8 por ciento. A los 14 DPT, el grupo I tuvo un PRH de 66.2 por ciento (IC = 13 por ciento-70 por ciento) y un PAP de 84 por ciento. En el grupo II el PRH fue de 100 por ciento (IC = 100 por ciento) y el PAP fue del 0 por ciento. El grupo III siempre tuvo un PAP del 100 por ciento. Los resultados indican la presencia de una población de H. contortus resistente al sulfóxido de albendazol. Aunque existen trabajos sobre resistencia de este parásito a bencimidazoles en México, ésta no se había registrado en contra del sulfóxido de albendazol inyectado, el cual está considerado como de primera elección contra estos nematodos