Infectious Disease Compendium

Brucella

Microbiology

Gram negative short rods. B. abortus, B. canis, B. melitensis, B. suis, B. neotomae. They can be very slow to grow, I had one blood culture turn positive on the 42nd day of incubation. Let the lab know you are looking for it in part as it is hard to grow but more importantly it is one of those organsims the lab tech can catch from the cultures. There is also serology.

Epidemiologic Risks

Worldwide, from expose to animals, especially unpasteurized dairy products.

B. abortus: cattle, buffalo, camels (Pubmed).

B. canis: found primarily in kennel-raised dogs.

B. melitensis: goats and sheep, less often camels, cattle herds in Israel.

B. suis biovars 1-3: domestic and wild swine in the US, dogs in the South (PubMed), cattle. B. suis biovar 4 reindeer and caribou, nearly caused the death of Santa, at least that is what I tell my kids as the reason why they did not get any Christmas presents: Santa had undulant fever. Same reason we have rabbit as our traditional Easter dinner.

Hare carcasses from Argentina, which are approved for human and animal consumption, caused a B. suis infection in a dog, which was fed a raw hare, in the Netherlands. But could be a risk for humans as well (PubMed).

Bison and elk spread (PubMed) it to livestock as can feral pigs. Good name for a band. Feral Pigs. Thrash metal for sure.

If you are hunting feral swine in the south, and kill one, the preparation of the carcass can lead to infection (MMWR). Also ritual the ritual slaughter of animals (PubMed).

B. neotomae, found in woodrats, infected two humans in Costa Rica (PubMed).

Syndromes

A nonspecific febrile syndrome 2 - 4 weeks after exposure. Depression is common, and the illness can be acute, subacute and local suppurative complications can occur anywhere, especially bone, joints, liver, CNS (PubMed), spleen, testicles, or kidneys. Eye involvement with chronic disease not uncommon; especially uveitis (PubMed). Fagets sign, pulse-temperature disassociation, may be a hint.

Treatment

Best bet may be doxycycline 100 mg twice a day and rifampin 10mg/kg body weight/day po for eight weeks, plus 7.5 mg/kg amikacin twice a day for seven days (PubMed) or gentamicin for the first week (PubMed).

Tetracycline 500 mg po qid OR doxycycline 100 po bid for 6 weeks WITH streptomycin 1 g/day im for the first 3 weeks OR doxycycline (100 mg administered orally twice daily for 45 days) in combination with either streptomycin (1 g administered intramuscularly daily for 14 days) or gentamicin (5 mg/kg per day administered intramuscularly for 7 days) are equivalent (PubMed) OR Doxycycline 100 po bid PLUS rifampin 600 to 900 mg/day po for 6 weeks. Ciprofloxacin and rifampin is also an option.

One meta-analysis suggests better outcomes with streptomycin over rifampin (PubMed)

CNS infections may require longer courses of therapy (PubMed).

For orchitis (oooooohhhhh) "doxycycline for 2 months and streptomycin for 14 to 21 days appears to be adequate and could avoid unnecessary orchiectomy (PubMed)." Always want to avoid unnecessary orchiectomy, although my one patient, a professional goat milker from Mexico, did not.

Spinal osteomyelitis is associated with poor outcomes and should be treated with at least three months of therapy (PubMed).

Notes

Beta-lactam antibiotics are active in vitro, don't believe it, also can't trust third generation cephalosporins or quinolones. The best antibiotics are the inracellular antibiotics.

DNA can be found in treated patients YEARS after therapy stops (PubMed).

There is a case of Brucella reactivating 28 years after initial infection (PubMed); I had a case years after leaving an endemic area (PubMed)(RDCT Blog).

It can be spread sexually male to female, although why someone would have sex with active orchitis is beyond me (PubMed).

Goats were source of nutrition on the hoof in the days before preservation. It was a problem for the British on the Rock of Gibraltar, where it was called Rock Fever and Mediterranean Fever amount others. Here is a 1905 report, where 15% of goats were seropositive (PubMed).

And a Brucella spinal infection has been found in a 2.5 million year old human fossil (PubMed).

Curious Cases

Relevant links to my Medscape blog

Ursine Questions

This Little Piggie

Surprise Follow Up

Last Update: 06/02/18.