Produces H2S gas and necrotizing orchitis
Epididymoorchitis is a focal form of human brucellosis described in 2%–20% of patients with brucellosis. We assessed
59 cases of Brucella epididymoorchitis (BEO) between 1991 and 1999. The median age of patients was 34 years
(range, 15–75 years). The onset of symptoms was acute in 46 patients (78%). Scrotal pain and swelling (100% of
patients), fever (88%), and sweating (73%) were the most common symptoms. Brucella species was isolated from blood
cultures in 41 patients (69%) and from epididymal aspiration in 4 patients. Treatment consisted of a combination of a
doxycycline and an aminoglycoside () or rifampin (); trimethoprim‐sulfamethoxazole with rifampin (); or trimethoprim‐
sulfamethoxazole as monotherapy (). The median duration of therapy was 45 days (range, 21–90 days). The infections
of 9 patients (15%) failed to respond to therapy, and 15 patients relapsed (25%). Three patients with necrotizing orchitis
whose infections were unresponsive to antibiotics required an orchiectomy. In general, classical brucellosis therapy is
adequate for BEO.
The four species of this genus that can infect humans are named for the animal which they are most
commonly found: B. abortus (cattle), B. suis (swine), B. melitensis (goats), B. canis (dogs). Brucella can enter the
body via the skin, respiratory tract, or digestive tract. Once there, this intracellular organism can enter the blood and the
lymphatics where it multiplies inside phagocytes and eventually cause bacteremia (bacterial blood infiltration).
Arthritis -- Chronic Infectious Arthritis
Chronic infectious arthritis develops over weeks and is usually caused by mycobacteria, fungi, or bacteria with low
Chronic infectious arthritis accounts for 5% of infectious arthritis and is most likely to develop in patients with RA, HIV
infection, immunosuppression, or prosthetic joints (see below); however, it can occur in otherwise normal individuals.
Examples of possible causes are Mycobacterium tuberculosis, M. marinum, M. kansasii, Candida sp, Coccidioides
immitis, Histoplasma capsulatum, Cryptococcus neoformans, Blastomyces dermatitidis, Sporothrix schenckii, Aspergillus
fumigatus, Actinomyces israelii, and Brucella sp. The arthritis of Lyme disease is usually acute but may be chronic.
Unusual opportunistic organisms are possible in HIV-infected patients. In chronic infectious arthritis, the synovial
membrane can proliferate and can erode articular cartilage and subchondral bone.
(Undulant, Malta, Mediterranean, or Gibraltar Fever)
Brucellosis is caused by Brucella sp. Symptoms begin as an acute febrile illness with few or no localized signs and
progress to a chronic stage with relapses of fever, weakness, sweats, and vague aches and pains. Diagnosis is by
culture, usually from the blood. Optimal treatment usually requires 2 antibiotics—doxycycline or trimethoprim-
sulfamethoxazole plus streptomycin or rifampin. Epidemiology The causative organisms of human brucellosis are
Brucella abortus (from cattle), B. melitensis (from sheep and goats), and B. suis (from hogs). B. canis (from dogs) has
caused sporadic infections. The most common sources of infection are farm animals and raw dairy products. Brucella
infections of deer, bison, horses, moose, caribou, hares, chickens, and desert rats have also occurred. Brucellosis is
acquired by direct contact with secretions and excretions of infected animals and by ingesting raw milk or milk products
containing viable organisms. It is rarely transmitted from person to person. Most prevalent in rural areas, brucellosis is
an occupational disease of meatpackers, veterinarians, hunters, farmers, and livestock producers. Brucellosis is rare in
the US, Europe, and Canada, but cases occur in the Middle East, Mediterranean regions, Mexico, and Central America.