Monday, December 4, 2017

Resistant bacteria infecting calves, people

The United States Centers for Disease Control reports an on-going outbreak of Salmonella Heidelberg infections in people who have been in contact with calves. 

What makes this worrisome is that these bacteria are resistant to most antibiotics.

Since the last update on August 2, eight more people have been reported ill from six states.
That brings the total to 54 people in 15 states.

Seventeen (35 per cent) of them have been hospitalized. None have died.

Illnesses started on dates ranging from January 27, 2015 to October 15, 2017.

Eighteen (33 per cent) of the sick people are children under the age of five.

Epidemiologic and laboratory investigations linked ill people in this outbreak to contact with calves, including dairy calves.

Some of the ill people interviewed reported that they became sick after their dairy calves became sick or died. Eighty-three per cent of the sick people were in contact with calves.

Ongoing surveillance in veterinary diagnostic laboratories showed that calves in several states continue to get sick with the outbreak strains of multidrug resistant Salmonella ‎
Information collected earlier in the outbreak indicated that most of the calves came from Wisconsin.

Whole genome sequencing has identified multiple antimicrobial resistance genes in outbreak-associated isolates from 43 ill people, 87 isolates from cattle, and 11 isolates from animal environments.

Isolates from eight ill people were resistant to amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftriaxone, streptomycin, sulfisoxazole, and tetracycline, and had reduced susceptibility to ciprofloxacin. Seven isolates were also resistant to trimethoprim-sulfamethoxazole.

Five were also resistant to nalidixic acid.

Three were also resistant to chloramphenicol.

All eight isolates tested were susceptible to azithromycin and meropenem.