Brucellosis — DTM&H MCQ

Correct answer: B — Doxycycline plus rifampicin for at least 6 weeks

The correct answer is B, doxycycline plus rifampicin for at least 6 weeks. This patient's occupational exposure (abattoir work), relapsing fever with sweats, back pain and hepatosplenomegaly, alongside slow-growing blood cultures and positive serology, are classic for Brucella infection, an intracellular organism that requires prolonged combination antibiotic therapy to achieve cure and prevent relapse. UK reference guidance from the Brucella Reference Unit specifies oral doxycycline plus rifampicin for 6 weeks as the standard regimen for those aged 12 years and older. Monotherapy or short courses fail to eradicate intracellular organisms and are associated with unacceptably high relapse rates, which is why combination therapy for a prolonged duration is mandated. Why the other options are wrong: C. Ceftriaxone single dose: this is the regimen for uncomplicated gonorrhoea, not brucellosis; a single dose cannot penetrate and clear an intracellular pathogen requiring weeks of therapy. E. Amoxicillin for 5 days: beta-lactams have poor intracellular penetration against Brucella and a 5 day course is far too short, leading to near-universal relapse. A. Metronidazole and paromomycin: this combination treats amoebiasis (metronidazole for tissue invasion, paromomycin for luminal cysts), not a zoonotic bacterial infection. D. Albendazole and ivermectin: these are antihelminthic agents used for conditions such as strongyloidiasis or filariasis, with no activity against Brucella bacteria. Key point: Occupational or dietary exposure plus undulant fever, night sweats, back pain and hepatosplenomegaly should trigger brucellosis testing, and confirmed cases need doxycycline plus rifampicin for a minimum of 6 weeks, never short courses or monotherapy.

Reference: UK Health Security Agency, Brucella Reference Unit, 'Brucella: laboratory and clinical services', GOV.UK: oral doxycycline plus rifampicin for 6 weeks (age 12 years or older). https://www.gov.uk/guidance/bru-reference-services