Relapsing bacteremia after blood transmission of Bartonella henselae to cats.

OBJECTIVES

To determine persistence of bacteremia, pathogenicity, and immunoglobulin kinetics after blood transmission of Bartonella henselae in cats.

ANIMALS

18 specific-pathogen-free (SPF) cats (16 weeks old) received blood or urine from 4 adult cats (2 SPF, 2 naturally infected with B henselae).

PROCEDURE

SPF cats were inoculated with blood IV (n = 4), blood IM (n = 4), or urine sediment IM (n = 4) from 2 bacteremic cats (donors A and B). Control cats (2/route) received inoculum from culture-negative, seronegative SPF cats (donors C and D).

RESULTS

6 cats (5 blood, 1 urine) were transiently febrile during the 213-day observation period. Two bacteremic cats developed CNS abnormalities. Transient anemia was the only hematologic abnormality. Bacteremia was induced in 7 of 8 blood recipients by postinoculation day (PID) 11. Urine recipients (n = 6) did not become bacteremic or seroconvert by PID 108, but when challenge exposed IV with blood, 4 of 6 became infected. All infected cats developed relapsing bacteremia. Initially, colony counts for donor-A recipients were 10(3) greater than those for donor-B recipients; however, during relapses, counts were similar. Polymerase chain reaction-restriction fragment length polymorphism analysis of 16S rRNA gene and the intergenic spacer region revealed no differences among isolates derived from recipient cats. Bartonella henselae-specific antibodies were detected between PID 15 and 18 in donor-A, compared with PID 46 and 181 in donor-B recipients. The peak geometric mean titer of donor-A recipients was 1,448, versus 406 for donor-B recipients.

CONCLUSIONS AND CLINICAL RELEVANCE

Blood transmission of B henselae induced subtle clinical abnormalities; the biological behavior of the 2 donor strains differed; and relapsing bacteremia can persist in conjunction with variably high antibody titers.