CDC Issues Health Advisory on Resistant Brucella Strain Found in Raw Milk

The Centers for Disease Control and Prevention (CDC) have issued an official health advisory regarding a rifampin/penicillin-resistant strain of RB51 Brucella that has been linked with the consumption of raw milk; this follows a health alert issued by the Texas Department of State Health Services (DSHS) that was issued back in mid-August.

The DSHS defines raw milk as “milk from cows or other animals that has not been pasteurized to kill harmful bacteria.” Raw milk can be contaminated with several different bacteria, including Listeria, Salmonella, Escherichia coli, and Campylobacter—all bacteria that are known to be responsible for countless disease outbreaks.

The individual who contracted brucellosis is a Texas resident who was exhibiting fever, muscle and joint pain, as well as fatigue. The DSHS reports that blood culture revealed the bacteria responsible for these symptoms was, in fact, Brucella. Further investigation tracked the infection back to a potential source: a licensed raw milk dairy based in Paradise, Texas, called K-Bar Dairy.

The CDC stresses that any individuals who have consumed raw milk from this dairy between June 1, 2017 and August 7, 2017 should “receive appropriate post-exposure prophylaxis (PEP).” These individuals are thus at increased risk for infection and should contact their healthcare providers to inquire about PEP and undergo potential diagnostic testing.

K-Bar Dairy has fully cooperated with the CDC’s investigation and has contacted customers and advised them to dispose of any milk that may be contaminated. However, the dairy does not have a record of all customers, therefore, the DSHS alerted the public about the recall on August 14, 2017.

The CDC reports that samples of the milk taken from the dairy have come back positive for a strain of Brucella called RB51, which is resistant to rifampin and penicillin. Therefore, the CDC recommends a PEP regimen for RB51 exposure consisting of a combination of doxycycline and trimethoprim/sulfamethoxazole to be taken for a course of 21 days.

“The DSHS is concerned that other people who consumed raw milk from K-Bar Dairy may also have been exposed to Brucella and became infected. Brucellosis may cause short-term and long-term disease,” according to the press release. “Without specific testing, this disease may elude correct diagnosis, and without appropriate antibiotic therapy, illness may persist.” The incubation period for the infection can range from 5 days to 6 months.

There is currently no serological test available to detect this specific strain of Brucella. Therefore, the CDC recommends that a blood culture be used as a diagnostic test for individuals exhibiting symptoms associated with Brucella infection. These symptoms can include any of the following: fever, sweats, malaise, anorexia, headache, muscle/joint/back pain, and fatigue. Some symptoms can persist for longer periods of time, be chronic, or potentially recur. Fevers, arthritis, swelling of testicles/scrotum area, endocarditis, chronic fatigue, liver/spleen swelling, and even depression have been noted as recurrent symptoms.

Because of the resistant strain, the CDC has specific recommendations when ordering blood cultures to diagnose the infection. They ask healthcare providers to “advise laboratory that blood culture may grow Brucella and that appropriate laboratory precautions should be observed. If brucellosis occurs despite prophylaxis, treatment regimens should be selected based on antimicrobial susceptibility results.”

As the investigation continues, the DSHS is urging health care providers to become familiar with brucellosis, “since it is an uncommon infection and can present with a wide variety of non-specific symptoms and signs that can wax and wane over weeks or even months.”