|Del Collo, Laura|
|Biswas, Debabrata - University Of Maryland|
|Lombard, Jason - Animal And Plant Health Inspection Services (APHIS), National Wildlife Center|
|Kristensen, Camila - Animal And Plant Health Inspection Service (APHIS)|
|Kopral, Christine - Animal And Plant Health Inspection Service (APHIS)|
|Fossler, Charles - Animal And Plant Health Inspection Service (APHIS)|
|Van Kessel, Jo Ann|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2016
Publication Date: 5/1/2017
Citation: Del Collo, L.P., Karns, J.S., Biswas, D., Lombard, J.E., Haley, B.J., Kristensen, C., Kopral, C.A., Fossler, C.P., Van Kessel, J.S. 2017. Prevalence, antimicrobial resistance, and molecular characterization of Campylobacter spp. in bulk tank milk and milk filters from US dairies. Journal of Dairy Science. 100:3470-3479.
Interpretive Summary: Although pasteurization is effective at controlling Campylobacter spp., this zoonotic pathogen is a common cause of foodborne outbreaks associated with nonpasteurized milk. Campylobacter spp. are commonly found on most dairy farms in the US and therefore can contaminate the milk that is collected on the farm. The purpose of this study was to determine the prevalence of thermophilic Campylobacter in bulk tank milk (BTM) and milk filters on US dairy farms. Samples were collected from farms in 17 states. The presence of Campylobacter spp. was detected in either BTM or filters from 24.9% of dairy operations and it was more frequently detected in samples from farm operations that had more than 100 cows than from smaller operations with less than 100 cows. Isolates were obtained in samples from 12.5% of the operations. C. jejuni was the most frequently isolated species and this species is also the most common Campylobacter species that causes human illness. This survey suggests that BTM from US dairies can be contaminated with pathogenic Campylobacter and this represents a potential risk to human health. This investigation benefits US dairy industries and consumers.
Technical Abstract: Campylobacter spp. are frequently isolated from dairy cows as commensal organisms. While sporadic Campylobacter infections in humans in the US are generally attributed to poultry, outbreaks (defined as 2 or more affected people) are commonly associated with dairy products, particularly nonpasteurized or raw milk. Bulk tank milk (BTM) samples and milk filters from US dairy operations were collected during the National Animal Health Monitoring System’s (NAHMS) Dairy 2014 study and analyzed by real-time PCR and traditional culture techniques for the presence of thermophilic Campylobacter species. The weighted prevalence (wp) of operations from which Campylobacter spp. were detected in either BTM or milk filters was 24.9%. Campylobacter spp. were detected in a higher percentage of operations with 100 – 499 cows (42.8%) and 500 or more cows (47.3%) than operations with 30-99 cows (4.9%). Campylobacter spp. were also more frequently detected in operations in the West than the East (46.5 and 21.8%, respectively). Campylobacter spp. were isolated from approximately half of the PCR-positive samples, representing 12.5% (wp) of operations. The majority (91.8%) of isolates were identified as C. jejuni, while C. lari and C. coli were also isolated. Resistance to tetracycline was detected in 68.4% of C. jejuni isolates while resistance to ciprofloxacin and nalidixic acid was detected in 13.2% of isolates. Based on pulsed-field gel electrophoresis analysis, dairy-associated C. jejuni are genomically diverse, but similar strains were isolated from geographically disparate regions. These results suggest that BTM can be contaminated with pathogenic Campylobacter spp. and that the consumption of nonpasteurized or raw milk presents a potential human health risk.