title: Prevalence, antimicrobial resistance, and molecular characterization of Campylobacter spp. in bulk tank milk and milk filters from US dairies.
abstract: Campylobacter spp. are frequently isolated from dairy cows as commensal organisms. Sporadic Campylobacter infections in humans in the United States are generally attributed to poultry, but outbreaks are also commonly associated with dairy products, particularly unpasteurized or raw milk. Bulk tank milk samples and milk filters from US dairy operations were collected during the National Animal Health Monitoring System Dairy 2014 study and analyzed using real-time PCR and traditional culture techniques for the presence of thermophilic Campylobacter species. The weighted prevalence of operations from which we detected Campylobacter spp. in either bulk tank milk or milk filters was 24.9%. We detected Campylobacter spp. in a higher percentage of operations with 100-499 cows (42.8%) and 500 or more cows (47.5%) than in operations with 30-99 cows (6.5%). Campylobacter spp. were also more frequently detected in operations in the west than the east (45.9 and 22.6%, respectively). We isolated Campylobacter spp. from approximately half of PCR-positive samples, representing 12.5% (weighted prevalence) of operations. The majority (91.8%) of isolates were C. jejuni, but C. lari and C. coli were also isolated. We detected resistance to tetracycline in 68.4% of C. jejuni isolates, and resistance to ciprofloxacin and nalidixic acid in 13.2% of C. jejuni isolates. Based on pulsed-field gel electrophoresis, we found that dairy-associated C. jejuni were genotypically diverse, although clonal strains were isolated from different geographic regions. These results suggest that bulk tank milk can be contaminated with pathogenic Campylobacter spp., and that the consumption of unpasteurized or raw milk presents a potential human health risk.
authors.affiliation: Environmental Microbial and Food Safety Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705; Department of Animal and Avian Sciences, University of Maryland, College Park 20742.
authors.forename: Laura P
authors.initials: LP
authors.lastname: Del Collo
authors.affiliation: Environmental Microbial and Food Safety Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Karns
authors.affiliation: Department of Animal and Avian Sciences, University of Maryland, College Park 20742.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Biswas
authors.affiliation: Center for Epidemiology and Animal Health, USDA-Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, CO 80526.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Lombard
authors.affiliation: Environmental Microbial and Food Safety Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705.
authors.forename: Bradd J
authors.initials: BJ
authors.lastname: Haley
authors.affiliation: Center for Epidemiology and Animal Health, USDA-Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, CO 80526.
authors.forename: R Camilla
authors.initials: RC
authors.lastname: Kristensen
authors.affiliation: Center for Epidemiology and Animal Health, USDA-Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, CO 80526.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Kopral
authors.affiliation: Center for Epidemiology and Animal Health, USDA-Animal and Plant Health Inspection Service, Veterinary Services, Fort Collins, CO 80526.
authors.forename: Charles P
authors.initials: CP
authors.lastname: Fossler
authors.affiliation: Environmental Microbial and Food Safety Laboratory, USDA-Agricultural Research Service, Beltsville, MD 20705. Electronic address: joann.vankessel@ars.usda.gov.
authors.forename: Jo Ann S
authors.initials: JAS
authors.lastname: Van Kessel
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents; D002167:Campylobacter / Q000302:isolation & purification*; D002169:Campylobacter Infections / Q000453:epidemiology; D002417:Cattle; D005260:Female; D008892:Milk; D015995:Prevalence
chemical_list: D000890:Anti-Infective Agents
keywords: Campylobacter; bulk tank milk; milk filter