An infant brucellosis meningitis caused by strain.

Brucellosis poses a significant health threat to the population, particularly to vulnerable populations, including infants. In this investigation, we retrospectively analyzed the infection source and potential transmission route in a three-month-old infant with febrile seizure. Bacteriology methods, epidemiological survey, Rose Bengal plate test (RBPT), and standard tube agglutination test (SAT) were used to diagnose the disease, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was applied to identify the strain. The study revealed that the infant's parents had been diagnosed with brucellosis due to occupational exposure to infected sheep. The strain was isolated and identified from the infant's blood sample, confirming brucellosis meningitis. Post-treatment serum analysis showed RBPT positivity and SAT titer of 1:200 (+ +). The infant had no direct contact with livestock, with breast milk as the only dietary source; however, the detailed transmission route remained undetermined. Maternal-fetal transmission or contamination through breastfeeding, parental hand contact, clothing exposure, or other passive contamination modes may be potential transmission routes. Notably, the parents had a history of brucellosis and given that the infant ​presented with a fever of unknown origin, screening for brucellosis should have been prioritized. Following diagnosis, the infant was treated with ceftriaxone sodium (2.0 g/day) and rifampicin (0.5 g/day) for four weeks, ultimately achieving full clinical recovery. This case highlights the importance of brucellosis screening in infants presenting with unexplained fever, especially in families whose members have previously been diagnosed with brucellosis in endemic regions.