Rifampin/Penicillin-Resistant Strain of RB51 Brucella Contracted from Consumption of Raw Milk

Health Alert Network logo.
This is an official CDC Health Advisory

Distributed via the CDC Health Alert Network

September 13, 2017, 1230 ET (12:30 PM ET)



The Texas Department of State Health Services, with assistance from CDC, is investigating Brucella RB51 exposures and illnesses that may be connected to the purchase and consumption of raw (unpasteurized) milk from K-Bar Dairy in Paradise, Texas. Symptoms of brucellosis can include: fever, sweats, malaise, anorexia, headache, fatigue, muscle & joint pain, and potentially more serious complications (e.g., swelling of heart, liver, or spleen, neurologic symptoms).


A person who drank raw milk from K-Bar Dairy in Paradise, Texas, has been hospitalized with brucellosis. Milk samples from the dairy have tested positive for a Brucella strain called RB51. People who consumed milk or milk products from this dairy from June 1, 2017, to August 7, 2017 are at an increased risk for brucellosis and should receive appropriate post-exposure prophylaxis (PEP). They are advised to consult with their health care providers regarding PEP care and possible diagnostic testing. Please note: the incubation period for brucellosis can range from five days to six months.


Brucella strain RB51 is resistant to rifampin and penicillin. A combination of doxycycline and trimethoprim/sulfamethoxazole for 21 days is the recommended first-line PEP regimen for RB51 exposure. There is no serological test available to detect RB51 infection. Blood culture is the recommended diagnostic test for exposed symptomatic individuals. When ordering blood cultures to diagnose brucellosis, please advise the laboratory that blood culture may grow Brucella and that appropriate laboratory1 precautions should be observed. If brucellosis occurs despite prophylaxis, treatment regimens2 should be selected based on antimicrobial susceptibility results. Please see the diagram below for information on developing an evaluation and treatment plan for exposed patients. Women who are pregnant or breastfeeding should consult with their health care provider.

Treatment Decision Tree for Patients Who Were Exposed to (Consumed) Raw Milk/Raw Milk Products
from K-Bar Dairy June 1, 2017 – August 7, 2017

Treatment Decision Tree for Patients Who Were Exposed to or Consumed Raw Milk or Raw Milk Products from K-Bar Dairy from June 1, 2017 to August 7, 2017


For More Information
Risks from Unpasteurized Dairy Products

Exposure to RB51 through Raw Milk or Milk Products: How to Reduce Risk of Infection

Brucellosis and Expecting Mothers

Raw Milk Questions and Answers

https://www.cdc.gov/cdc-info/index.html or 1-800-232-4636
CDC Emergency Operations Center (EOC)
Bacterial Special Pathogens Branch
bspb@cdc.gov or 404-639-1711

1Biosafety in Microbiological and Biomedical Laboratories

2Treatment of Brucellosis (for alternative treatment guidance)

Brucellosis Reference Guide

The Centers for Disease Control and Prevention (CDC) protects people’s health and safety by preventing and controlling diseases and injuries; enhances health decisions by providing credible information on critical health issues; and promotes healthy living through strong partnerships with local, national and international organizations.

Department of Health and Human Services

HAN Message Types

  • Health Alert: Conveys the highest level of importance about a public health incident.
  • Health Advisory: Provides important information about a public health incident.
  • Health Update: Provides updated information about a public health incident.

This message was distributed to state and local health officers, state and local epidemiologists, state and local laboratory directors, public information officers, HAN coordinators, and clinician organizations.