Prevalence of Bartonella infection in domestic cats in Denmark

Whole blood and serum from 93 cats (44 pets and 49 shelter/stray cats) from Denmark were tested for the presence of feline Bartonella species by culture and for the presence of Bartonella antibodies by serology. Bartonella henselae was isolated from 21 (22.6%) cats. Bacteremia prevalence was not statistically different between shelter/stray cats (13/49, 26.5%) and pet cats (8/44, 18.2%), but varied widely by geographical origin of the cats, even after stratification for cat origin or age (p < 0.001). All isolates but one were B. henselae type II. The only cat bacteremic with B. henselae type I was not co-infected with B. henselae type II. None of the cats was harboring either B. clarridgeiae or B. koehlerae. Almost half (42/92, 45.6%) of the cats were seropositive for B. henselae and antibody prevalence was similar in shelter/stray cats (23/49, 46.9%) and pet cats (19/43, 44.2%). This is the first report of isolation of B. henselae from domestic cats in Denmark. This study also indicates that domestic cats, including pet cats, constitute a large Bartonella reservoir in Denmark.     

Serological and molecular evidence of exposure to arthropod-borne organisms in cats from northeastern Spain

One hundred sixty-eight cat sera from Spain were tested for IgG antibodies to Rickettsia conorii (Rc), Ehrlichia canis (Ec), Anaplasma phagocytophilum (Ap) and Bartonella henselae (Bh) antigens using IFA and for FeLV antigen and FIV antibody by ELISA. For 47 whole blood samples, PCR testing was performed for Rickettsia, Ehrlichia and Bartonella. Seroprevalences were: Bh (71.4%), Rc (44%), Ec (11.3%), FeLV (8.5%), FIV (7.4%) and Ap (1.8%). Bh antibodies were associated with seroreactivity to both Ec and Rc antigens. FIV antibodies were associated with illness and cats older than 2 years. Bartonella henselae and B. clarridgeiae (Bcl) DNA was amplified from seven and one sample, respectively.     

Detection and characterization of feline Bartonella henselae in the Czech Republic

The aims of the study were to characterize isolates of Bartonella henselae and to determine the prevalence of bacteremic domestic cats in urban and suburban parts of Prague, Czech Republic. Five (18%) gram-negative fastidious bacterial single-cat isolates were recovered from 27 hemocultures incubated without previous freezing. Four of these isolates originated from flea infested stray cats (n=6) and one from a shelter cat without any ectoparasites (n=21). None of the 34 previously frozen specimens from flea free pet cats yielded any bacteria. All five isolates were catalase and oxidase negative. Their enzymatic activity, RFLP profile of citrate synthetase gene (gltA) and DNA-DNA hybridization results were typical of B. henselae. According to their PvuII and BglI ribotypes the isolates could be allocated to two homogeneous groups. Ribotype HindIII and RFLP of 16S-23S rRNA spacer region analysis gave unique profiles different from those of Bartonella quintana, Bartonella elizabethae and Bartonella clarridgeiae. The 16S rRNA type-specific amplification revealed an identical profile typical of B. henselae genotype II for all the cat isolates studied. Pulsed-field gel electrophoresis (PFGE) assigned a different profile to each of the isolates studied. Determination of the enzymatic activity, RFLP of gltA gene, RFLP of 16S-23S rRNA spacer region, and HindIII ribotype could be efficient tools for identification of B. henselae isolates. Ribotyping (PvuII, BglI), 16S rRNA typing and PFGE may be useful methods to prospect ecology and epidemiology of the agent.     

Epidemiology of Bartonella infection in domestic cats in France

Blood samples were collected between February and June 1996 from a convenience sample of 436 domestic French cats living in Paris and its environs and were tested for Bartonella bacteremia and seropositivity. Seventy-two cats (16.5%) were Bartonella bacteremic, of which 36 cats (50%) were infected with Bartonella henselae type II (B.h. II) only, 15 cats (21%) were infected with Bartonella clarridgeiae (B.c.) only, and 11 cats (15%) were infected with B. henselae type I (B.h. I) only. Eight cats (11%) were co-infected with B. henselae and B. clarridgeiae (B.h. II/B.c.: five cats; B.h. I/B.c.: three cats). Two cats (2.8%) were concurrently bacteremic with B. henselae types I and II. Risk factors associated with bacteremia included ownership for <6months (prevalence ratio (PR)=1.80; 95% confidence interval (CI)=1.13-2.85), adoption from the pound or found as a stray (PR=1.67, 95% CI=1.05-2.65), and cohabitation with one or more cats (PR=1.60, 95% CI=1.01-2.53). Bartonella antibodies to either B. henselae or B. clarridgeiae were detected in 179 cats (41.1%). Risk factors associated with seroposivity paralleled those for bacteremia, except for lack of association with time of ownership. Prevalence ratios of bacteremic or seropositive cats increased with the number of cats per household (p=0.02). The lack of antibodies to B. henselae or B. clarridgeiae was highly predictive of the absence of bacteremia (predictive value of a negative test=97.3%). Multiple logistic regression analysis indicated that bacteremia, after adjustment for age and flea infestation, and positive serology, after adjustment for age, were associated with origin of adoption and number of cats in the household. Flea infestation was associated with positive serology.     

Genomic diversity of Bartonella henselae isolates from domestic cats from Japan, the USA and France by pulsed-field gel electrophoresis

The genomic DNA diversity of 27 Bartonella henselae and three B. clarridgeiae isolates from 18 domestic cats from Japan, the USA and France was investigated by pulsed-field gel electrophoresis (PFGE) with NotI, AscI and SmaI restriction enzymes. A great diversity of genomic patterns was found for all B. henselae, but none for B. clarridgeiae isolates. The DNA size of B. henselae and B. clarridgeiae isolates were 1.7-2.9 and 1.7Mbp, respectively. All 13 Japanese cat isolates were identified as B. henselae type I. Furthermore, three of the four Japanese cats harbored genetically different B. henselae type I isolates, suggesting for the first time co-infection with various type I isolates.One French cat and one American cat were co-infected with B. henselae and B. clarridgeiae. B. henselae type I and type II were mainly grouped in two different clusters by PFGE using SmaI endonuclease in the dendrogram.     

Prevalence of Bartonella henselae, Bartonella clarridgeiae and the 16S rRNA gene types of Bartonella henselae among pet cats in Japan

The authors investigated bacteriologically the prevalence of Bartonella infection among 690 pet cats derived from 10 private animal hospitals in six cities (Sapporo, Hokkaido Prefecture; Sendai, Miyagi Prefecture; Joetsu, Niigata Prefecture; Fujisawa, Kanagawa Prefecutre; Kyoto, Kyoto Prefecture; Sanda, Hyogo Prefecutre) and 4 counties (Mishima, Osaka Prefecture; Hikawa, Shimane Prefecture; Aira, Kagoshima Prefecture; Shimajiri, Okinawa Prefecture) located from the north to the south of Japan. Bartonella species were isolated from 7.2% (50/690) of all the cats examined. No Bartonella species were isolated from the cats in Sapporo or Sendai. The isolation rate varied from 2% in Joetsu and Sanda to 20% in Shimajiri. Bartonella clarridgeiae was isolated from two of 50 cats in Kyoto, three of 50 in Mishima and one of 50 in Shimajiri, but not in cats from the other cities or counties. Though the cats of Joetsu, Fujisawa, Kyoto, Sanda, Aira and Shimajiri were infected with either B. henselae or B. clarridgeiae, one of eight infected cats in Mishima was harboring both Bartonella species. Type I of 16S rRNA gene was the predominant type among the isolates of B. henselae, but only one isolate derived from Shimajiri was found to be of type II. Prevalence of B. clarridgeiae and the 16S rRNA gene type of B. henselae among cats in Japan was demonstrated for the first time in this investigation.     

Molecular evidence for Bartonella spp. in cat and dog fleas from Germany and France

Nine hundred and fifty-two fleas were collected from 148 cats and 133 dogs at 18 widely distributed geographic locations in Germany and France and examined for the presence of six different Bartonella spp. (Bartonella bacilliformis, Bartonella clarridgeiae, Bartonella elizabethae, Bartonella henselae, Bartonella quintana, Bartonella vinsonii subsp. berkhoffii) by PCR. Thirty-five specimens (3.7%) tested positive for either B. henselae (14 positive fleas) or B. clarridgeiae (21 positive fleas). DNA of other Bartonella spp. were not detected. Bartonella clarridgeiae was the dominating species in samples from France (19 out of 22 positive fleas), whereas B. henselae was more frequent in Germany (11 out of 13 positive fleas). With 3.5% (22 out of 632 fleas) in France and 4.1% (13 out of 320 fleas) in Germany, the overall prevalences of pathogen did not vary significantly between the flea populations of both countries. 5.4% of cats in France versus 16.1% of cats from Germany were infested by fleas carrying Bartonella, whereas 9.5% of dogs in France but none of the examined dogs from Germany were infested by Bartonella positive fleas. The molecular evidence of Bartonella infections reveals that agents of zoonotic potential are established in flea populations in Germany and France and that the spectrum of species can vary significantly from country to country.     

Infection and re-infection of domestic cats with various Bartonella species or types: B. henselae type I is protective against heterologous challenge with B. henselae type II

Four Bartonella species have been isolated from domestic cats, of which two serotypes/genotypes of Bartonella henselae and possibly B. clarridgeiae are human pathogens, causing cat scratch disease (CSD).Our objectives were to evaluate infection and potential cross-protection during re-infection in domestic cats with various Bartonella species or types.Thirty-six cats were primarily inoculated with B. henselae type I (n=16), B. henselae type II (n=10), B. clarridgeiae (n=6) or B. koehlerae (n=4). They were challenged with B. henselae type I (n=15), B. henselae type II (n=13) or B. clarridgeiae (n=8).All 36 cats became bacteremic (1.25x10(2)-1.44x10(6)CFU/ml) and bacteremia lasted from 37 to 582 days. Duration of bacteremia for cats inoculated with B. henselae type I was shorter than for cats inoculated with either B. henselae type II (P=0.025) or B. clarridgeiae (P=0.011).After challenge, 26 cats became bacteremic. Among the nine cats primarily inoculated with B. henselae type I and challenged with B. henselae type II, six cats stayed abacteremic. The three bacteremic cats had a transient low-level bacteremia. No bacteremia was observed in three cats primarily inoculated with B. henselae type I and challenged with another strain of B. henselae type I. Bacteremia levels in the 26 cats were significantly lower than for primary inoculation (P=0.022) and its duration was shorter (P=0.012). Among the eight cats challenged with B. clarridgeiae, duration of bacteremia in the four cats primarily inoculated with B. henselae type I was shorter than in the four cats primarily inoculated with B. henselae type II (P=0.01). Bartonella clarridgeiae inoculated cats were more likely to have relapses for both primary and secondary infections.This is the first demonstration of cross-protection, evidenced by absence of bacteremia, in cats primarily infected with B. henselae type I and challenged with B. henselae type II, whereas no cross-protection was previously shown for cats primarily infected with B. henselae type II and challenged with B. henselae type I. Such results are of major importance for future feline Bartonella vaccine development.     

Evaluation and use of a nested polymerase chain reaction assay in cats experimentally infected with Bartonella henselae genotype I and Bartonella henselae genotype II.

Cats have been shown to be infected with Bartonella henselae genotype I, B. henselae genotype II, and B. clarridgeiae. Feline bartonellosis infections and the strains involved in these infections are important in both veterinary and human medicine. Nucleic acid amplification methods such as polymerase chain reaction (PCR) are being used in both research and diagnostics as tools for understanding many infectious diseases. Bartonella bacteremia in cats is detected by blood culture; however, because of the limitations of culture (delayed turnaround time and sensitivity limits), PCR may be a more efficient method for identifying infected cats. Three distinct PCR assays that could differentiate among B. henselae genotype I, B. henselae genotype II. and B. clarridgeiae were developed and used to detect as few as 3.2 organisms. Fourteen cats experimentally infected with B. henselae genotype I and B. henselae genotype II were followed by bacterial culture and PCR through the course of infection, including periods of primary and relapsing bacteremia. The PCR assay was positive in 11 of the 14 cats for periods of 1-9 weeks after culture became negative. Of the 223 blood specimens that were culture negative, the PCR assay was positive in 38 (17%) of the specimens. Two of the 14 cats developed relapsing bacteremia. The 2 B. henselae genotypes were amplified in the cats and the bacteremic phase of these infections as determined by PCR lasted for a longer period than previously determined by culture. Using laboratory assays such as PCR to understand the strains involved in feline bartonellosis and the course of the infection is important in the understanding of these zoonotic agents.     

Bartonella spp antibodies and DNA in aqueous humour of cats.

Bartonella spp antibodies were measured in the serum and aqueous humour of cats with and without uveitis and polymerase chain reaction (PCR) for Bartonella spp DNA was performed on aqueous humour from most of the cats. Serum and aqueous humour were assayed from 49 client-owned cats with uveitis, 49 healthy shelter cats, and nine cats experimentally inoculated with either B henselae or B clarridgeiae, 454 days after inoculation. An aqueous antibody coefficient (C value) was calculated for cats positive for Bartonella spp antibodies in the aqueous humour. Ocular production of Bartonella spp IgG (C value >1) was detected in seven of 49 cats with uveitis, none of 49 healthy shelter cats, and four of nine experimentally inoculated cats. The organism was detected by PCR in the aqueous humour of three of 24 cats with uveitis, one of 49 healthy shelter cats, and four of nine experimentally inoculated cats. Bartonella spp infect the eyes of some cats following natural exposure or experimental inoculation and may cause uveitis in some cats.     

Seroprevalence of antibodies against Bartonella species and evaluation of risk factors and clinical signs associated with seropositivity in dogs

OBJECTIVE: To determine the seroprevalence of antibodies against Bartonella spp in a population of sick dogs from northern California and identify potential risk factors and clinical signs associated with seropositivity. SAMPLE POPULATION: Sera from 3,417 dogs. PROCEDURE: Via an ELISA, sera were analyzed for antibodies against Bartonella vinsonii subsp berkhoffii, Bartonella clarridgeiae, and Bartonella henselae; test results were used to classify dogs as seropositive (mean optical density value > or = 0.350 for B henselae or > or = 0.300 for B clarridgeiae or B vinsonii subsp berkhoffi) or seronegative. Overall, 305 dogs (102 seropositive and 203 seronegative dogs) were included in a matched case-control study. RESULTS: 102 of 3,417 (2.99%) dogs were seropositive for > or = 1 species of Bartonella. Of these, 36 (35.3%) had antibodies against B henselae only, 34 (33.3%) had antibodies against B clarridgeiae only, 2 (2.0%) had antibodies against B vinsonii subsp berkhoffii only, and 30 (29.4%) had antibodies against a combination of those antigens. Compared with seronegative dogs, seropositive dogs were more likely to be herding dogs and to be female, whereas toy dogs were less likely to be seropositive. Seropositive dogs were also more likely to be lame or have arthritis-related lameness, nasal discharge or epistaxis, or splenomegaly. CONCLUSIONS AND CLINICAL RELEVANCE: Only a small percentage of dogs from which serum samples were obtained had antibodies against Bartonella spp. Breed appeared to be an important risk factor for seropositivity. Bartonella infection should be considered in dogs with clinical signs of lameness, arthritis-related lameness, nasal discharge or epistaxis, or splenomegaly.     

Bartonella species antibodies and DNA in cerebral spinal fluid of cats with central nervous system disease

Bartonella species infection is associated with central nervous system (CNS) disease in some humans and cats but the diagnosis is difficult to confirm with blood or serum test results. In this retrospective study of 100 client-owned cats, serum and cerebral spinal fluid (CSF) were assayed for Bartonella species IgG antibodies and CSF was assayed for Bartonella species DNA. Bartonella species IgG antibodies were detected in serum of 36 cats, Bartonella species C-values>1 (suggesting antibody production by the CNS) were detected in CSF of 11 cats, and B henselae DNA was amplified from the CSF of 10 cats. While the clinical significance of these findings cannot be assessed without a control group, the development of neurological signs in some cats inoculated with B henselae and the results of this study warrant prospective evaluation of the association of Bartonella species with feline CNS disease.     

Prevalence of Bartonella species DNA and antibodies in cats (Felis catus) submitted to a spay/neuter program in Rio de Janeiro, Brazil

The prevalence of Bartonella species DNA and antibodies for Bartonella henselae were studied in 40 clinically healthy cats (Felis catus, Linnaeus 1758) submitted to a spay/neuter program in Rio de Janeiro, Brazil. Additionally, the prevalence of Bartonella species DNA was investigated in the fleas found parasitizing the subject cats. For this purpose, blood samples were obtained from all cats, and DNA extraction was performed on the blood, and blood clotted samples, as well as on pools of fleas obtained from them. Antibodies for B henselae were detected on serum samples. Bartonella species DNA was detected in 17 cats, whereas serum reactivity for B henselae was found in 19. A total of 20 cats were flea-infested and nine of these 20 had Bartonella species DNA in their blood. In four of the 20 flea-infested cats, Bartonella species DNA was detected in the fleas obtained from those cats, but only one of these four cats had Bartonella species DNA in its blood.     

Prevalence of Bartonella species causing bacteraemia in domesticated and companion animals in the United Kingdom

Between October 1999 and February 2000, 691 blood samples examined routinely for either haematological or virological assessment were screened by culture for the presence of Bartonella species. They came from 615 animals: 360 cats, 211 dogs, 27 horses, 16 cattle and a gorilla. The samples were incubated for long periods on 10 per cent horse blood agar at 37 degrees C in an atmosphere containing 5 per cent carbon dioxide. Isolates were obtained from 35 samples from 34 (9.4 per cent) of the cats, but not from any of the other animals. Comparison of citrate synthase gene sequences from the isolates indicated that they were all Bartonella henselae. Analysis of 16S rRNA gene fragments indicated that 30 of the cats were infected solely with B henselae genotype II, two were infected solely with B henselae genotype I and two were infected with both genotypes.     

Prevalence of Bartonella infection in wild African lions (Panthera leo) and cheetahs (Acinonyx jubatus)

Bartonella species are emerging pathogens that have been isolated worldwide from humans and other mammals. Our objective was to estimate the prevalence of Bartonella infection in free-ranging African lions (Panthera leo) and cheetahs (Acinonyx jubatus). Blood and/or serum samples were collected from a convenience sample of 113 lions and 74 cheetahs captured in Africa between 1982 and 2002. Whole blood samples available from 58 of the lions and 17 of the cheetahs were cultured for evidence of Bartonella spp., and whole blood from 54 of the 58 lions and 73 of the 74 cheetahs tested for the presence of Bartonella DNA by TaqMan PCR. Serum samples from the 113 lions and 74 cheetahs were tested for the presence of antibodies against Bartonella henselae using an immunofluorescence assay. Three (5.2%) of the 58 lions and one (5.9%) of the 17 cheetahs were bacteremic. Two lions were infected with B. henselae, based on PCR/RFLP of the citrate synthase gene. The third lion and the cheetah were infected with previously unidentified Bartonella strains. Twenty-three percent of the 73 cheetahs and 3.7% of the 54 lions tested by TaqMan PCR were positive for Bartonella spp. B. henselae antibody prevalence was 17% (19/113) for the lions and 31% (23/74) for the cheetahs. The prevalence of seropositivity, bacteremia, and positive TaqMan PCR was not significantly different between sexes and age categories (juvenile versus adult) for both lions and cheetahs. Domestic cats are thus no longer the only known carriers of Bartonella spp. in Africa. Translocation of B. henselae seronegative and TaqMan PCR negative wild felids might be effective in limiting the spread of Bartonella infection.     

Seroprevalence of and risk factors for Bartonella henselae and Bartonella quintana infections among pet cats in Jordan

To determine the seroprevalences of Bartonella henselae and Bartonella quintana antibodies in Jordanian pet cats, serum samples from 153 cats from three geographical regions were analyzed. Seroprevalences were determined by indirect immunofluorescence. The true seroprevalences to B. henselae and B. quintana were 32 and 1.5%, respectively. The seroprevalence of B. henselae-specific antibodies in cats from northern Jordan was significantly higher than in cats from the central or southern parts of Jordan. The seroprevalence to B. henselae increased to age 2 years. Odds of seropositivity were higher in cats living outdoors, showing hunting behavior, having a flea infestation and of a mixed breed. No association was detected with sex.     

Bartonella henselae IgG antibodies are prevalent in dogs from southeastern USA

In contrast to the large body of literature regarding Bartonella henselae in humans and cats, there is little information about B. henselae as an infectious agent in dogs. Due to the paucity of information regarding the B. henselae serology in dogs, we performed a cross-sectional serosurvey using B. henselae antigen in order to compare the seroprevalence between sick and healthy dogs from the south-eastern USA. Ninety-nine sera were collected from clinically healthy dogs. Three hundred and one sera from sick dogs were submitted to North Carolina State University for serologic screening against a panel of arthropod-transmitted organisms. Serological tests were performed using B. henselae (Bh), Rickettsia rickettsii (Rr), Ehrlichia canis (Ec), Bartonella vinsonii subspecies berkhoffii (Bvb), Babesia canis (Bc) and Borrelia burgdorferi (Bb) antigens. Serum B. henselae IgG antibodies were detected in 10.1% of healthy dogs and in 27.2% of sick dogs. The difference in seroprevalence between the two groups was statistically significant. The majority of seroreactive dogs (80%) had low titers of 1:64 or 1:128. In healthy dogs, seroprevalence for Rr was 14.1% and for Bvb was 1%. In sick dogs, Rr seroprevalence was 29.7%, Ec 6.5%, Bvb 4.7%, Bb 1.7% and Bc was 0.85%. Of the sick dogs that were seroreactive to B. henselae antigens, 40.6% were also seroreactive to Rr, 15.0% reactive to Bvb antigens, 14.8% reactive to Ec antigens, 1.8% reactive to Bc antigens and 1.75% reactive to Bb antigens. Sera from dogs experimentally infected with B. vinsonii subsp. berkhoffii, E. canis or R. rickettsii did not cross react with B. henselae antigens, by IFA testing. This study indicates that B. henselae IgG antibodies are prevalent in healthy and sick dogs living in the south-eastern USA. Nevertheless, further studies are needed to evaluate the epidemiological, clinical and zoonotic relevance of B. henselae infection in dogs.     

Prevalence of Bartonella species, haemoplasma species, Ehrlichia species, Anaplasma phagocytophilum, and Neorickettsia risticii DNA in the blood of cats and their fleas in the United States

Ctenocephalides felis were killed and collected from 92 cats in Alabama, Maryland, and Texas. The fleas and blood from the corresponding cat were digested and assessed in polymerase chain reaction assays that amplify DNA of Ehrlichia species, Anaplasma phagocytophilum, Neorickettsia risticii, Mycoplasma haemofelis, 'Candidatus M haemominutum' and Bartonella species. DNA consistent with B henselae, B clarridgeiae, M haemofelis, or 'Candidatus M haemominutum' was commonly amplified from cats (60.9%) and their fleas (65.2%). Results of this study support the recommendation to maintain flea control on cats in endemic areas.     

A serological investigation of Bartonella henselae infection in cats in Turkey

Bartonella henselae is the causative agent of cat scratch disease (CSD) in humans. Cats are the main reservoir of this bacterium and may infect humans through scratches and bites. The purpose of this study was to determine the B. henselae seroprevalence in cats in Turkey. A total of 298 cats blood samples were collected from six different provinces of Turkey. Sera were tested for the presence of anti-B. henselae IgG antibodies by indirect fluorescent antibody test (IFA). The seroprevalence of B. henselae was 27.9% (83/298) for the cats examined in this study. The seroprevalence of cats by province was significantly higher in Bursa (41.3%), Adana (33.9%), Aydin (27.5%) and Burdur (32.3%) than in Kayseri (17.9%) and Istanbul (12.5%). Statistically significant differences were not observed between cat sexes and living conditions of cats. The results revealed that B. henselae is an important zoonotic pathogen in Turkey.     

Microbial culture of blood samples and serologic testing for bartonellosis in cats with chronic rhinosinusitis

OBJECTIVE: To assess the role of Bartonella spp in chronic rhinosinusitis (CRS) by determining detection rates for the organism by serologic testing and microbial culture of blood samples for Bartonella spp in cats with CRS and control cats (cats with other nasal diseases, cats with systemic illnesses, and healthy cats). DESIGN: Prospective case-control study. ANIMALS: 19 cats with CRS, 10 cats with other nasal diseases, 15 cats with systemic illness, and 15 healthy cats. Procedures-Serologic testing for Bartonella clarridgeiae and Bartonella henselae and microbial culture of blood samples were conducted in all cats. In cats with CRS and cats with other nasal diseases, a nasal biopsy specimen was submitted, when available, for tissue PCR assay to detect Bartonella spp. RESULTS: 9 of 19 cats with CRS had positive results for serologic testing for 1 or both Bartonella spp; whereas, 4 of 10 cats with other nasal diseases, 2 of 15 cats with systemic diseases, and 4 of 15 healthy cats had positive results for serologic testing to detect Bartonella spp. These values did not differ significantly among groups. Microbial culture of blood samples yielded B henselae in 1 cat with a nasopharyngeal abscess. The PCR assay for Bartonella spp in nasal tissues yielded negative results for 9 of 9 cats with CRS and 5 of 5 cats with other nasal diseases. CONCLUSIONS AND CLINICAL RELEVANCE: A role for Bartonella spp in the pathogenesis of CRS in cats was not supported by results of this study.