CDC Health Advisory about Third Case of Rifampin Penicillin-Resistant Strain of RB51 Brucella from Consuming Raw Milk

PUBLISHED: Jan 24, 2019
Relevant to: All Healthcare Organizations

The U.S. Centers for Disease Control and Prevention (CDC) has issued a Health Advisory regarding a third case of Rifampin/Penicillin-Resistant Strain of RB51 Brucella from consuming raw milk. According to the Health Advisory, the New York State Department of Health and Pennsylvania Department of Health are investigating Brucella RB51 exposures that may be connected to consuming raw (unpasteurized) milk from Miller's Biodiversity Farm in Quarryville, Pennsylvania. As of January 22, 2019, exposures have been identified in 19 states: Alabama, California, Connecticut, Florida, Georgia, Iowa, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, and Virginia.

The Advisory reports of a third known case of brucellosis from Brucella RB51 due to raw milk acquired in the U.S., since August 2017. A New York resident, who drank raw milk purchased from Miller’s Biodiversity Farm in Quarryville, Pennsylvania, was diagnosed with brucellosis in November 2018. Milk samples from the dairy tested positive for Brucella strain RB51. People who consumed raw milk or raw milk products from this dairy since January 2016 may have been exposed.

  • Patients who are still within six months of the date they last consumed the raw milk are at an increased risk for brucellosis and appropriate post-exposure prophylaxis (PEP) is recommended, along with six months of symptom monitoring. Please see diagram in the Health Advisory.
  • If patients are outside of the six-month window following their last consumption of the raw milk and have or develop an illness consistent with brucellosis, a blood culture should be obtained prior to starting any treatment, preferably while the patient is symptomatic.

Brucella strain RB51 is a live-attenuated cattle vaccine strain, which can be shed in milk and can cause infections in humans. RB51 is resistant to rifampin and penicillin. There is no serological test available to detect RB51 infection. Blood culture is the recommended diagnostic test for exposed individuals who are symptomatic

Symptoms of brucellosis can include fever, sweats, malaise, anorexia, headache, fatigue, muscle and joint pain, and potentially more serious complications (e.g., endocarditis, hepatomegaly, splenomegaly, and neurologic symptoms). In pregnant patients, Brucella infections can be associated with miscarriage. Symptom onset can occur anywhere from five days to six months following exposure.

The Centers for Disease Control and Prevention (CDC) recommends the following:

  • A 21-day course of both doxycycline and trimethoprim/sulfamethoxazole for first-line PEP for RB51 exposure. If brucellosis occurs despite prophylaxis, treatment should be pursued; alternative options should be considered for those with contraindications to the stated PEP and treatment regimens. Please note that RB51 is resistant to rifampin and penicillin.
  • When ordering blood cultures to diagnose brucellosis, please advise the laboratory that blood culture may grow Brucella and that appropriate laboratory containment and precautions should be observed.
  • Advise patients to discard any leftover or stored, raw milk or raw milk products from this dairy farm.

Please see the diagram in the Health Advisory, link below, for information on developing an evaluation and treatment plan for patients who consumed raw milk or raw milk products from Miller’s Biodiversity Farm since January 2016 and are still within the six-month window following their last known exposure.

Brucella is a national notifiable condition. The Nationally Notifiable Disease List provides comprehensive reporting of diseases that occur in the United States. The list is compiled through collaborative efforts among state health departments and the CDC. Reporting of diseases is mandated by state legislation and regulations, please verify reporting requirements for your state.

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