Infectious Disease and Microbiology - Bartonella quintana

Basics

Bartonella quintana is a small intracellular coccobacillus formerly known as Rochalimaea quintana. It is best known as the cause of trench fever, but it can also produce persistent bacteremia, endocarditis, and bacillary angiomatosis, particularly in immunocompromised patients.

Microbiologic Characteristics

Bartonella quintana is:

• A small coccobacillus

• Intracellular

• Fastidious and slow growing

Because routine cultures may fail to detect the organism promptly, specialized culture techniques and molecular methods are often useful.

Incubation Period

The incubation period is usually about:

7–30 days

After this period, patients may develop an acute or relapsing febrile illness.

Epidemiology

B. quintana has been reported from multiple endemic areas around the world, including parts of:

• Eastern Europe

• The former Soviet region

• Africa

• South America

Historically, trench fever became prominent among soldiers living in crowded and unhygienic conditions.

The principal vector is the:

Human body louse

Transmission is strongly associated with poor hygiene, crowding, and body-louse infestation.

Trench Fever

Trench fever is the classic infection caused by B. quintana.

The disease may present as an acute or relapsing febrile illness.

Typical symptoms can include:

• Fever

• Chills

• Headache

• Malaise

• Myalgias

• Bone pain, especially involving the shins

• Fatigue

The fever may recur in episodes, giving the disease a relapsing pattern.

High-Yield Clinical Pattern

Body-louse exposure

• ●

Recurrent fever

• ●

Severe shin or bone pain

→ Think trench fever due to Bartonella quintana.

Bacteremia

B. quintana can produce persistent or recurrent bacteremia.

This is especially important in socially vulnerable or immunocompromised patients.

Patients may have:

• Recurrent fever

• Malaise

• Weakness

• Few focal findings

Persistent bacteremia can predispose to infective endocarditis.

Endocarditis

Bartonella quintana is an important cause of culture-negative endocarditis.

Patients may present with:

• Prolonged fever

• Cardiac murmur

• Weight loss

• Embolic phenomena

• Heart failure in advanced disease

Routine blood cultures may remain negative because the organism is slow growing and fastidious.

Therefore, Bartonella should be considered when endocarditis is clinically suspected but standard cultures do not reveal an organism.

Bacillary Angiomatosis

In immunocompromised patients, particularly those with advanced HIV infection, B. quintana can cause bacillary angiomatosis.

The lesions are produced by abnormal vascular proliferation and may appear:

• Red

• Violaceous

• Papular

• Nodular

• Friable

They can resemble Kaposi sarcoma.

Peliosis Hepatis

Although more classically associated with B. henselae, Bartonella infection can also be associated with peliosis hepatis.

This involves blood-filled cystic spaces within the liver and may produce:

• Fever

• Abdominal pain

• Hepatomegaly

• Abnormal liver enzymes

Diagnosis

Diagnosis can be challenging because B. quintana is a fastidious organism.

Useful methods include:

• Specialized blood culture

• Cell culture

• PCR

• Serology in selected settings

Blood Culture

Lysis-centrifugation systems may improve recovery from blood.

Because growth is slow, prolonged incubation may be required.

A negative routine blood culture does not exclude Bartonella infection.

PCR

PCR is particularly helpful for detecting Bartonella DNA in:

• Blood

• Cardiac valve tissue

• Skin lesions

• Other infected tissues

Molecular testing can be especially valuable in culture-negative endocarditis.

Treatment

Bacteremia Without Endocarditis

A commonly used regimen is:

Doxycycline 100 mg orally every 12 hours for 4 weeks

plus

Gentamicin 3 mg/kg/day intravenously for the first 2 weeks

The aminoglycoside provides important bactericidal activity during the early phase of treatment.

Endocarditis

For Bartonella endocarditis, treatment is prolonged.

A commonly used regimen is:

Doxycycline 100 mg orally every 12 hours for at least 6 weeks

plus

Gentamicin 3 mg/kg/day intravenously for the first 2 weeks

Endocarditis should be managed with infectious-disease and cardiology involvement because valve destruction and heart failure may occur.

Bacillary Angiomatosis

A typical regimen is:

Doxycycline 100 mg orally every 12 hours for 3–4 months

Longer treatment may be required if immune suppression persists or relapse occurs.

Additional Treatment Options

Macrolides may also be useful, including:

• Erythromycin

• Azithromycin

Choice depends on the clinical syndrome, susceptibility considerations, drug interactions, and patient tolerance.

Prevention

The key preventive strategy is elimination of the vector:

Human body louse

Important measures include:

• Treatment of louse infestation

• Washing or replacing infested clothing and bedding

• Improving access to hygiene

• Reducing overcrowding

• Laundering clothes at appropriately high temperatures

Vector control is central because B. quintana transmission is closely linked to body lice.

High-Yield Trench Fever Pattern

Body-louse infestation

• ●

Relapsing fever

• ●

Headache and shin pain

→ Bartonella quintana

High-Yield Endocarditis Pattern

Prolonged fever

• ●

Cardiac murmur

• ●

Repeatedly negative routine blood cultures

• ●

Risk factors for body-louse exposure

→ Consider Bartonella quintana endocarditis

High-Yield Immunocompromised Pattern

Advanced immunosuppression

• ●

Red or violaceous vascular skin lesions

→ Consider bacillary angiomatosis due to Bartonella quintana or B. henselae

Exam Essentials

Organism:

→ Bartonella quintana

Former name:

→ Rochalimaea quintana

Microbiology:

→ Small intracellular coccobacillus

Vector:

→ Human body louse

Incubation:

→ 7–30 days

Classic disease:

→ Trench fever

Characteristic symptom:

→ Relapsing fever with severe shin or bone pain

Other major infections:

→ Bacteremia, endocarditis, bacillary angiomatosis

Important endocarditis clue:

→ Culture-negative endocarditis

Diagnosis:

→ Specialized blood culture, cell culture, PCR

Bacteremia treatment:

→ Doxycycline for 4 weeks + gentamicin for first 2 weeks

Endocarditis treatment:

→ Doxycycline for at least 6 weeks + gentamicin for first 2 weeks

Bacillary angiomatosis:

→ Prolonged doxycycline

Additional options:

→ Erythromycin or azithromycin

Prevention:

→ Eradicate body lice

Key distinction:

B. henselae → cats

B. quintana → body lice / trench fever