Bartonellosis

Question 1

What infections are caused by Bartonella species?

Answer 1

Cat scratch disease, retinitis, trench fever, relapsing bacteremia, culture-negative endocarditis, bacillary angiomatosis (BA), bacillary peliosis hepatis.

Fourteen Bartonella species have been implicated in human infections.

Question 2

In which population does bacillary angiomatosis (BA) most often occur?

Answer 2

Individuals who are immunocompromised, particularly those with HIV and CD4 counts <50 cells/mm3.

BA can last months to over a year in people with HIV.

Question 3

What is the vector for B. quintana?

Answer 3

Body louse.

B. quintana is associated with body louse infestation and homelessness.

Question 4

What is the primary vector for B. henselae in humans?

Answer 4

Cat fleas.

Cats are the most common vector responsible for transmitting B. henselae to humans.

Question 5

What are common clinical manifestations of bacillary angiomatosis (BA)?

Answer 5

Cutaneous lesions, subcutaneous nodules, osteomyelitis, systemic symptoms (fever, night sweats, weight loss).

BA lesions can resemble Kaposi sarcoma and pyogenic granuloma.

Question 6

How is the diagnosis of BA confirmed?

Answer 6

Histopathologic examination of biopsied tissue.

BA lesions show vascular proliferation and numerous bacilli with modified silver stains.

Question 7

What is the role of serologic testing in diagnosing Bartonella infections?

Answer 7

It helps in diagnosis and monitoring treatment response.

Anti-Bartonella antibodies may not be detectable for 6 weeks after acute infection.

Question 8

What is the recommended treatment for Cat Scratch Disease?

Answer 8

Doxycycline 100 mg PO or IV every 12 hours, or Erythromycin 500 mg PO or IV every 6 hours.

Both are considered first-line treatments.

Question 9

What is the duration of therapy for all manifestations of Bartonella infection in patients with HIV?

Answer 9

At least 3 months.

Long-term suppressive therapy may be needed if relapse occurs.

Question 10

What is the indication for long-term suppressive therapy for Bartonella?

Answer 10

Relapse after a ≥3-month course of primary treatment with CD4 count <200 cells/mm3.

Some specialists suggest a 4-fold decrease in Bartonella titers as a criterion.

Question 11

Which antibiotics should not be used for treating bartonellosis?

Answer 11

Penicillins and first-generation cephalosporins.

These have no in vivo activity against Bartonella.

Question 12

What are the potential adverse effects associated with macrolides?

Answer 12

Nausea, vomiting, abdominal pain, elevations of liver transaminases, potential QT interval prolongation.

Serious side effects can occur with rifamycin class antibiotics.

Question 13

True or False: Primary chemoprophylaxis for Bartonella-associated disease is recommended.

Answer 13

False.

A macrolide was found protective against developing Bartonella infection in a case-control study.

Question 14

What should patients treated with oral doxycycline be cautioned about?

Answer 14

Pill-associated esophagitis and photosensitivity.

Monitoring of antibody titers is recommended during treatment.

Question 15

What is the importance of monitoring anti-Bartonella antibody levels?

Answer 15

To assess treatment response and detect potential relapse of infection.

Sequential endpoint titers should be checked every 6 to 8 weeks.

Question 16

Fill in the blank: The cat flea is the vector for _______ in cats.

Answer 16

B. henselae.

This is a key transmission route to humans.

Question 17

What are the major risk factors for acquiring B. henselae?

Answer 17

Contact with cats infested with fleas, receiving cat scratches.

Immunocompromised individuals should consider risks of cat ownership.

Question 18

What should be done if a person with HIV has a cat-associated wound?

Answer 18

Wash it promptly with soap and water.

This is critical to prevent potential infection.

Question 19

What is the recommended monitoring frequency for sequential endpoint titers during treatment?

Answer 19

Every 6 to 8 weeks during treatment

Preferably until at least a fourfold decrease is documented.

Question 20

What side effects should patients treated with oral doxycycline be cautioned about?

Answer 20

Pill-associated esophagitis and photosensitivity

Adverse effects should be communicated to patients.

Question 21

List some adverse effects associated with macrolides.

Answer 21

• Nausea
• Vomiting
• Abdominal pain
• Elevations of liver transaminase levels
• Potential QT interval prolongation

These effects should be monitored during treatment.

Question 22

What serious side effects can occur with rifamycin class antibiotics?

Answer 22

• Hypersensitivity reactions
• Thrombocytopenia
• Interstitial nephritis
• Hemolytic anemia
• Hepatitis

These side effects necessitate careful monitoring.

Question 23

How do rifamycin class antibiotics affect the cytochrome P450 enzyme system?

Answer 23

They strongly induce the cytochrome P450 enzyme system

This is important when other medications are taken simultaneously.

Question 24

What is a recommended action for patients who fail to respond to initial treatment for Bartonella infections?

Answer 24

Switch to a different preferred regimen

For example, from doxycycline to erythromycin, with treatment duration of ≥3 months.

Question 25

What should be done for severe Bartonella infections?

Answer 25

Addition of a rifamycin class antibiotic is indicated ## Footnote This is a recommendation for severe cases.

Question 26

When should treatment for Bartonella infections continue after clinical improvement is observed?

Answer 26

Until at least a fourfold decrease in antibody titers is documented ## Footnote This is crucial for ensuring effective management.

Question 27

What is recommended after a primary course of treatment for Bartonella infections?

Answer 27

Close monitoring for evidence of relapse ## Footnote This includes monitoring symptoms and antibody titers.

Question 28

What is the recommendation if a relapse of Bartonella infection occurs?

Answer 28

An additional course of treatment is recommended ## Footnote Followed by long-term suppression of infection.

Question 29

How long can long-term suppression therapy be discontinued after effective treatment?

Answer 29

After at least 3 to 4 months of therapy ## Footnote Provided the CD4 count remains >200 cells/mm3 on effective ART for ≥6 months.

Question 30

What complications are associated with B. bacilliformis infection during pregnancy?

Answer 30

Increased complications and risk of death ## Footnote Data on B. quintana or B. henselae during pregnancy is not available.

Question 31

What should be used as first-line therapy for Bartonella infections during pregnancy?

Answer 31

Erythromycin or an alternative macrolide ## Footnote Tetracyclines like doxycycline are avoided due to risks.

Question 32

What is the recommendation for cephalosporins in treating Bartonella infections in pregnant people?

Answer 32

Third-generation cephalosporins may have efficacy ## Footnote Considered second-line therapy after a macrolide.

Question 33

Which cephalosporins are not recommended for Bartonella infections?

Answer 33

First- and second-generation cephalosporins ## Footnote Due to their lack of efficacy against Bartonella.