Population dynamics of Salmonella enterica following single dose metaphylactic antibiotic use within cohorts of beef cattle followed to slaughter.

Population dynamics of Salmonella enterica following single dose metaphylactic antibiotic use within cohorts of beef cattle followed to slaughter. Appl Environ Microbiol. 2019 Sep 13;: Authors: Levent G, Schlochtermeier A, Ives SE, Norman KN, Lawhon SD, Loneragan GH, Anderson RC, Vinasco J, Scott HM Abstract Antibiotic use in cattle can select for multidrug-resistant Salmonella enterica, which is considered a serious threat by the U.S. Centers for Disease Control and Prevention. A randomized controlled longitudinal field trial was designed to determine the long-term effects of a single dose of ceftiofur or tulathromycin on Salmonella population characteristics among cattle feces, peripheral lymph nodes, and hides. A total of 134 beef cattle from two sources was divided among 12 pens, with cattle in each of the three-pen blocks receiving either a single dose of ceftiofur or tulathromycin on Day 0, or else neither (control). Fecal samples were collected before treatment (Day 0), and repeatedly following treatment until slaughter (Day 99+). Hide and lymph node samples were collected at slaughter age. Salmonella prevalence, phenotypic antimicrobial resistance, serotype, and phylogenetic relationships were examined. Multilevel mixed logistic regression models indicated no significant effects (P ≥0.218) of metaphylactic antibiotic on prevalence of Salmonella across sample types. However, there was a significant day effect observed with p...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research