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Bartonellosis 113

after culture in an insect growth media is the can develop rapid antimicrobial resistance to Recommended Monitoring
preferred test method but is still prone to macrolides. Supportive care for the specific • Clinical response to treatment
VetBooks.ir single sample is tested. long-term treatment with a combination of treatment, repeat titers at 1 month and 6 Diseases and Disorders
• For animals that were seropositive before
manifestation of disease is important. Usually,
false-negative results, especially when only a
months after treatment may be informative
antibiotics is recommended to combat infection,
Differential Diagnosis
biological cure.
prognostic indicator, but an unchanged titer
• The differential diagnosis list is broad and but it is unlikely to produce complete micro- (resolution of antibody response is a good
varies with the disease manifestation. may suggest additional antimicrobial therapy
• Consider co-infection with other vector Acute General Treatment is warranted).
transmitted pathogens. • Usually, a combination of a fluoroquinolone • For seronegative animals, consider repeating
• Consider routine bacterial endocarditis (p. and tetracycline is recommended for 4-12 serology 2-3 weeks after starting antibiotics
294). weeks. to document seroreactivity and support for
○ For stable animals, start with only one clinical diagnosis.
Initial Database antimicrobial drug and then add the • Ideally, BAPGM enrichment PCR is repeated
• CBC, serum chemistry profile, urinalysis: second several days to 1 week later. This 2 and 6 weeks after completion of therapy.
variable depending on manifestation; can is to avoid the rare but potentially serious
be entirely normal complication of a Jarisch-Herxheimer–like PROGNOSIS & OUTCOME
○ May recognize thrombocytopenia, anemia, reaction. This reaction, presumably due
monocytosis, or eosinophilia to bacterial death and cytokine release by Varies; prognosis for endocarditis is guarded,
○ With liver involvement, liver enzymes can the host, usually begins 4 to 7 days after but other manifestations may respond well
be increased therapy is begun and results in fever, to treatment. Recurrent or persistent infec-
• Imaging studies: variable depending on lethargy, and vomiting. tion is possible with any species or disease
manifestation. With endocarditis, evidence ○ Enrofloxacin 10 mg/kg PO q 24h (dogs) manifestation.
of cardiomegaly and CHF is possible. or pradofloxacin 7.5-10 mg/kg PO q 24h
• Retroviral and hemotropic Mycoplasma (cats) PEARLS & CONSIDERATIONS
testing (cats) to rule out concurrent infection ○ Doxycycline or minocycline 10 mg/kg PO
• Other tests as indicated by history and q 12h (dogs) or 8.8 mg/kg q 24h (cats); Comments
examination (e.g., with suspected endocar- note the dose required is higher than that • Currently, there is a steep learning curve
ditis, echocardiogram and routine blood required to treat other vector-borne infec- regarding bartonellosis in animals and
culture are indicated) tions such as ehrlichiosis. humans, with new species and vectors rec-
• In animals with life-threatening manifesta- ognized routinely. Similarly, new potential
Advanced or Confirmatory Testing tions such as endocarditis and associated disease manifestations related to these
• Serologic tests: extremely poor sensitivity to heart failure, initial additional use of ami- infections are recognized on a frequent basis.
detect infection noglycoside antibiotics has been suggested If bartonellosis is suspected, it is worth
○ Only 50% of dogs infected with B. vinsonii (e.g., amikacin 15-30 mg/kg IV, IM, or SQ consultation with a veterinary internal
subsp berkhoffii and 25% of dogs infected q 24h for 7-10 days [dog] or 10-14 mg/kg medicine or microbiology specialist for the
with B. henselae are seropositive. IV, IM, or SQ q 24h [cat]) most up-to-date information.
○ A single positive titer demonstrates • Due to rapid antibacterial resistance, the use • In areas with high flea burdens, seropreva-
prior infection but cannot prove disease of azithromycin is no longer recommended. lence of Bartonella spp in cats can be > 90%,
causation. • Address specific disorders as appropriate; for with bacteremia rates of > 50%.
○ A fourfold increase in titer over 2-3 weeks example • Seroprevalence rates for Bartonella spp in
can confirm acute infection. ○ Endocarditis (p. 294) dogs vary, but risk is higher for free-roaming
• Culture of organisms from blood, another ○ CHF (p. 408) male dogs living in rural areas.
bodily fluid, or tissue: ○ Uveitis (p. 1023) • B. henselae bacteria remain viable in flea feces
○ Positive culture is often possible from for at least 9 days.
infected reservoir host Possible Complications • Humans become infected by inoculation of
○ Culture is rarely positive from accidental • Jarisch-Herxheimer–like reaction 4-7 days flea feces when cats (or dogs) scratch or bite;
host after initiation of therapy the best way to avoid zoonotic infection is
• Routine PCR: poor sensitivity • Tetracycline drugs can cause esophageal strict flea control.
• PCR after enrichment in insect growth irritation and stricture; follow tablet/capsule • There is no benefit to serologic testing of a
media: improved sensitivity with food or water. Compounded liquid cat for Bartonella spp before adoption.
○ Blood/fluid/tissue is first cultured in tetracyclines have a short shelf life. • There is no benefit to antimicrobial treatment
insect-based liquid culture media (Bar- • Treatment failure of a healthy, seropositive cat because 1) it is
tonella alpha Proteobacteria growth
medium [BAPGM]) for ≥ 7 days.
○ PCR assay applied to amplify Bartonella
from media Select Bartonella Species and Reservoir Host
○ Galaxy Diagnostics, Inc. (contact@galaxydx Bartonella Species Reservoir Host Potential Vectors Accidental Hosts
.com, Morrisville, NC)
○ Optimal results with fresh-frozen tissue B. clarridgeiae Cats Fleas, ticks Humans, dogs
or three blood samples collected at dif- B. henselae Cats, dogs Fleas, ticks Humans, dogs
ferent times
B. koehlerae Cats, gerbils Fleas Humans
TREATMENT Candidatus B. merieuxii Dogs Fleas
B. rochalimae Dogs Sandflies Humans
Treatment Overview B. vinsonii subsp berkhoffii Coyotes, dogs, foxes Ticks Humans
An optimal protocol for treatment of bartonel-
losis has not been established. Bartonella spp Adapted from Breitschwerdt EB: Bartonellosis, One Health and all creatures great and small. Vet Dermatol 28:96-e21, 2017.

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