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CDC links multistate, multidrug-resistant Salmonella outbreak to dairy bull calves
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The CDC has linked a multistate outbreak of multidrug-resistant Salmonella Heidelberg infections to contact with dairy bull calves, according to a recent statement.
To date, 21 infections and eight hospitalizations were reported in eight states. The dates of illness onset ranged from Jan. 11 to Oct. 24; however, the CDC said there may be additional infections that occurred after Oct. 24. No deaths were reported.
Dairy bull calf
Source: CDC
Among 19 patients with available information, 15 reported contact with cattle, including dairy bull calves. According to the CDC, dairy bull calves are young, uncastrated male cattle that may be raised for meat. Some patients said they became ill after their dairy bull calves became ill or died.
The source of infections was eventually linked to dairy bull calves from livestock markets in Wisconsin. The animals involved in the outbreak were purchased for 4-H projects.
Researchers from the Wisconsin State Laboratory of Hygiene performed antibiotic resistance testing on clinical isolates collected from ill patients and determined that all isolates were closely related and resistant to antibiotics. Whole genome sequencing revealed multiple antimicrobial resistant genes in isolates obtained from 15 patients and eight cattle. Two isolates tested at CDC’s National Antimicrobial Resistance Monitoring System laboratory were resistant to amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftriaxone, chloramphenicol, nalidixic acid, streptomycin, sulfisoxazole, tetracycline and trimethoprim-sulfamethoxazole, and had reduced susceptibility to ciprofloxacin.
The CDC said it will continue to investigate the outbreak with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service and state health and agriculture officials.