Infection of fetal feline brain cells in culture with Bartonella henselae

Bartonella henselae is known to cause central nervous system (CNS) disease in humans, and neurological signs have been observed in experimentally infe cted cats. However, the pathogenesis of CNS disease remains unclear. This s tudy was undertaken to determine whether B. henselae infects feline fetal b rain cells in vitro. Microglial-cell- and astrocyte-enriched cultures were inoculated with B. henselae. Gimenez staining identified bacterial organism s within microglial cells by day 7 postinoculation. The viability of the in tracellular bacteria was demonstrated by incubating cultures with gentamici n and plating cell lysate on agar. Electron microscopy identified intracell ular organisms with characteristic Bartonella morphology but identified no ultrastructural abnormalities within infected microglial cells. No evidence of infection was seen in Bartonella-inoculated astrocyte cultures. These f indings suggest a role for microglia in the pathogenesis of B. henselae-ass ociated neurological disease.