EXPERIMENTALLY-INDUCED BARTONELLA-HENSELAE INFECTIONS FOLLOWED BY CHALLENGE EXPOSURE AND ANTIMICROBIAL THERAPY IN CATS

Objectives-To elucidate kinetics of Bartonella henselae bacteremia and IgG response, evaluate antibiotic therapy, and investigate challenge exposure in cats. Animals-Specific-pathogen-free cats. Procedure-Cats were inoculated with B henselae or B quintana and monitored. Convalesc ent cats were challenge exposed with B henselae. Amoxicillin, enroflox acin, erythromycin, and tetracycline HCl were evaluated for effect on B henselae bacteremia. Results-Cats developed B henselae bacteremia wi thin 1 week; bacteremia persisted for longer than 2 months before subs iding spontaneously. IgG antibody titer developed shortly after onset of bacteremia; antibody coexisted with bacteremia for several weeks an d remained detectable after bacteremia subsided. Cats inoculated with B quintana remained abacteremic. On challenge exposure to B henselae, cats previously infected with B henselae remained abacteremic; cats pr eviously inoculated with B quintana supported B henselae infection. Te tracycline HCl and erythromycin depressed B henselae bacteremia; howev er, duration of bacteremia remained similar to that in untreated cats. Obvious signs of illness were not observed. Conclusions-Long-duration , high-titer B henselae infections were highly reproducible in cats. C onvalescent cats were immune to reinfection. B quintana-inoculated cat s did not have evidence of infection and were susceptible to B hensela e challenge exposure. Antibiotic therapy was incompletely efficacious in terminating cat bacteremia. Clinical Relevance-A cat with an inappa rent B henselae infection must provisionally be regarded as a possible reservoir for infection for a minimum of 2 to 3 months. Convalescent cats are resistant to reinfection. Usual antibiotic therapy was not co mpletely efficacious. Measurement of IgG antibody can be used to detec t past or current infection.