Molecular Mechanisms Associated with the Development of the Metritis Complex in Dairy Cattle.

The metritis complex (MC), a group of post-partum uterine diseases, is associated with increased treatment costs and reduced milk yield and fertility. The goal of this study was to identify genetic variants, genes, or genomic regions that modulate MC disease. A genome-wide association study was performed using a single-locus mixed linear model of 1967 genotypes (624,460 SNPs) and metritis complex records. Then, in-silico functional analyses were performed to detect biological mechanisms and pathways associated with the development of MC. The ATP8A2, COX16, AMN, and TRAF3 genes, located on chromosomes 12, 10, and 21, were associated with MC at p ≤ 0.0001. These genes are involved in the regulation of cholesterol metabolism in the stromal tissue of the uterus, which can be directly associated with the mode of transmission for pathogens causing the metritis complex. The modulation of cholesterol abundance alters the efficiency of virulence factors and may affect the susceptibility of the host to infection. The SIPA1L1, DEPDC5, and RNF122 genes were also significantly associated with MC at p ≤ 0.0001 and are involved in the PI3k-Akt pathway, responsible for activating the autophagic processes. Thus, the dysregulation of these genes allows for unhindered bacterial invasion, replication, and survival within the endometrium.

Control of Escherichia coli O157:H7 using lytic bacteriophage and lactic acid on marinated and tenderized raw pork loins.

Escherichia coli (E. coli) O157:H7- contaminated pork and production environments, are often a major source of foodborne outbreaks. This study evaluated the inhibition of E. coli O157:H7 on artificially contaminated raw pork loins using lytic bacteriophage (phage) and lactic acid (LA). Pork samples were inoculated with 106 CFU/mL of E. coli O157:H7 cocktail and stored at 4 °C for 30 min for the initial surface attachment. Inoculated pork loins were randomly assigned to a treatment group (Control, DI water, LA 2.5%, phage 5%, and LA 2.5% + phage 5%; n = 6/group/replication). Following antimicrobial treatments and marination for 1 h, surface microbial population was enumerated. Phage 5% significantly reduced (P < 0.05) the microbial load by 1.90 logs in pre-tenderized loins and > 2.50 logs in post-tenderized loins. Likewise, the combined treatment of phage 5% and LA 2.5% significantly reduced (P < 0.05) the microbial load by 1.89 logs in pre-tenderized loins and > 1.75 logs in post-tenderized loins. The data showed that the use of lytic bacteriophages and lactic acid as antimicrobials can result in a reduced risk of E. coli O157:H7 on the surface of pork loins.

Salmonella spp. Response to Lytic Bacteriophage and Lactic Acid on Marinated and Tenderized Raw Pork Loins.

Bacterial food poisoning cases due to Salmonella have been linked with a variety of pork products. This study evaluated the effects of a Salmonella-specific lytic bacteriophage and lactic acid (LA) on Salmonella Enteritidis, Salmonella Montevideo, and Salmonella Heidelberg growth on raw pork loins. Pork loins were cut into approximately 4 cm thick slices. Pork slices were randomly assigned to five treatment groups (control, DI water, LA 2.5%, phage 5%, and LA 2.5% + phage 5%) with six slices per group per replication. Pork loins were inoculated with 106 CFU/mL of Salmonella spp. and stored at 4 °C for 30 min. After 1 h of treatment application and marination, phage 5% significantly (p < 0.05) reduced the surface bacterial population by 2.30 logs when compared with the control group. Moreover, the combined treatment of LA 2.5% + phage 5% significantly (p < 0.05) reduced the surface bacterial population by more than 2.36 logs after 1 h of marination. In the post-tenderization surface samples, the combination of both phage and LA showed a significant reduction (p < 0.05) when compared with the control group. However, the treatments had no effect (p > 0.05) when analyzing the translocation of pathogens on pork loins.

Salmonella Typhimurium DT 104 response to Lytic bacteriophage and Lactobionic acid on raw chicken breast.

Bacterial food poisoning cases due to Salmonella have been linked with a variety of poultry products. This study evaluated the effects of a Salmonella-specific Lytic bacteriophage and Lactobionic acid (LBA) on Salmonella Typhimurium DT 104 growth on raw chicken breast meat. Each chicken breast was randomly assigned to a treatment group (Control, DI water, phage 1%, phage 5%, LBA 10 mg/mL, LBA 20 mg/mL, and phage 5% + LBA 20 mg/mL) with four chicken breasts per group. Samples were inoculated with 106 CFU/mL of Salmonella and stored at 4 °C for 30 min. The inoculated chicken breasts were randomly assigned to different storage time (0 h, 1 h, 24 h, or 48 h). Both time and treatment showed significance reduction (P < 0.0001) of microbial growth. The weight loss was significantly different (P < 0.0001) between treatments. The LBA treatments were not effective when compared to the control group, but Lytic bacteriophage significantly reduced the amount of microbial growth.