Background

• Pathogens from the genus Bartonella can infect people and result in bartonellosis. RBC-adhering microbes were first described by AL Barton in 1909. For the lone member of the group discovered before 1993, the term Bartonia, later Bartonella bacilliformis, was used. 
• A recent combination of Bartonella and the related group Rochalimaea occurred. Even though Bartonella bacteria can be cultured on artificial media, rickettsiae are not, contrary to what was formerly believed about these organisms. 
• The bacterium Bartonella henselae is primarily transmitted to humans through scratches or bites from infected cats.  

Epidemiology

• Geographical distribution: Bartonellosis is a worldwide disease, occurring in various regions across the globe. Higher rates of Bartonellosis have been reported in temperate regions, such as North America, Europe, and parts of Asia. It is less common in tropical regions. 
• Age and sex: Bartonellosis can affect individuals of all ages, but it is more commonly seen in children and adolescents. This is likely due to their increased likelihood of close contact with cats and kittens. In some studies, the male gender has been associated with a higher incidence of the disease. 

Anatomy

Pathophysiology

• The primary mode of transmission of Bartonella henselae to humans is through scratches or bites from infected cats. The bacteria reside in the saliva of infected cats and can penetrate the skin barrier when a scratch or bite occurs. The bacteria then enter the local tissue, initiating the infection. 
• When Bartonella enters the body, it hunts for CD34+ cells, a subset of white blood cells that serve as a source of progenitor endothelium cells, which line blood arteries and other tissues. Once inside the cell, it stops the cell from self-destructing and surrounds itself with a vacuole for protection. 
• The main virulence component of Bartonella is an endotoxin known as lipid A, which is typically located in the outer membrane of gram-negative bacteria. Invasion of endothelium and erythrocyte cells by the organism is a key factor in the pathophysiology of the disease process.  
• The organism modifies the immune system in such a way that it leaves the host more vulnerable to infections from other bacterial diseases.  

Etiology

• Bartonella henselae is a gram-negative bacterium that belongs to the genus Bartonella, within the family Bartonellaceae. It is a small, rod-shaped bacterium that can grow and multiply within various cells, including red blood cells, endothelial cells lining blood vessels, and immune cells. 
• The primary reservoir hosts for Bartonella henselae are domestic cats, particularly kittens. Cats become infected with the bacteria through fleas, ticks, or contact with infected cats. The bacteria can colonize the cat’s oral cavity and are shed in the saliva, as well as in the feces. 
• angiomatosis, the agent that causes Carrion’s illness, is characterized by a high-grade fever, severe anemia brought on by the loss of red blood cells, significant enlargement of the spleen and liver, bleeding into the lymph nodes, and blood vessel damage. 

Genetics

Prognostic Factors

• Children and adolescents are more commonly affected by Bartonellosis, and they tend to have milder diseases compared to adults. Although relapses and chronic bacterial states are well documented, trench fever is a non-lethal, self-limiting condition.  
• Individuals with compromised immune systems, such as those with HIV/AIDS or undergoing immunosuppressive therapy, may experience more severe and prolonged Bartonellosis. 
• Individuals with pre-existing medical conditions, such as liver disease or systemic lupus erythematosus, may be at increased risk of developing complications from Bartonellosis. 
• In 22 instances reported by Raoult and colleagues in 1996, 19 patients underwent valvular surgery, and 6 patients passed away from bartonella endocarditis, which frequently necessitates surgical correction.  

Clinical History

• Bartonellosis is more commonly seen in children and adolescents. This age group often has a higher incidence of CSD (cat scratch disease) due to their increased likelihood of close contact with cats, especially kittens. Engaging in activities that involve playing with or handling cats puts them at a higher risk of acquiring Bartonella henselae infection. 
• Young adults can also be affected by Bartonellosis, although the incidence tends to be lower compared to children and adolescents.  

Physical Examination

Age group

Associated comorbidity

Associated activity

• People with weakened immune systems, such as those with HIV/AIDS, undergoing immunosuppressive therapy or with other immune disorders, may be at higher risk for more severe or prolonged Bartonellosis. The immune system plays a crucial role in controlling the infection, and compromised immunity can lead to an increased risk of complications. 
• Individuals with pre-existing liver disease, such as cirrhosis or chronic hepatitis, may have impaired immune function and may be more susceptible to complications from Bartonellosis.  

Acuity of presentation

• The symptoms typically develop within 1 to 3 weeks after exposure to an infected cat or a cat scratch/bite. The initial signs may include a small papule or pustule at the site of injury, which can be accompanied by localized redness, swelling, and tenderness. 
• As the infection progresses, regional lymphadenopathy (enlarged and tender lymph nodes) develops near the site of the scratch or bite. The affected lymph nodes may become painful and form abscesses in severe cases.  

Differential Diagnoses

• Staphylococcal or streptococcal skin infections: These can cause localized skin lesions, including abscesses and cellulitis, which may resemble the initial papule or pustule of Bartonellosis. 
• Tularemia: This bacterial infection, caused by Francisella tularensis, can result in skin ulcers and enlarged lymph nodes, similar to Bartonellosis. 
• Mycobacterial infections: Certain mycobacterial infections, such as Mycobacterium marinum or atypical mycobacteria, can cause skin lesions and lymphadenopathy resembling Bartonellosis. 
• Herpes simplex virus (HSV) infection: HSV can cause skin lesions, including painful ulcers or vesicles, which may be mistaken for Bartonellosis. 
• Epstein-Barr virus (EBV) infection: EBV can lead to lymphadenopathy and systemic symptoms, like Bartonellosis.  

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

avoid-scratching-or-irritating-skin-lesions

•  If you have skin lesions or cat scratches, it’s important to avoid scratching or picking at them.
• Scratching can introduce additional bacteria and lead to infection.

supportive-care

• Bartonellosis can cause flu-like symptoms, such as fever, fatigue, and body aches.
• Supportive care measures, such as drinking plenty of fluids, using over-the-counter pain relievers like acetaminophen or ibuprofen to manage fever and pain.  

Use of Antibiotic selection

• Azithromycin: It is often considered the first-line treatment for uncomplicated cases. It is usually administered orally once daily. Azithromycin is generally well-tolerated, but it may cause gastrointestinal side effects such as nausea, vomiting, or abdominal pain. 
• Doxycycline: It is another commonly used antibiotic and is typically administered orally twice daily.  
• Potential side effects include gastrointestinal symptoms, photosensitivity (increased sensitivity to sunlight), and, rarely, liver toxicity. 
• Ciprofloxacin: This antibiotic may be used if there are specific reasons to avoid azithromycin or doxycycline. It is administered orally or intravenously. 

Use of combination therapy with doxycycline and <a class="wpil_keyword_link" href="https://medtigo.com/drug/rifampin/" title="rifampin" data-wpil-keyword-link="linked">rifampin</a>

• Doxycycline is a broad-spectrum antibiotic from the tetracycline class. It is effective against Bartonella henselae, the bacteria responsible for cat scratch disease. Doxycycline inhibits bacterial protein synthesis, thereby preventing the growth and replication of the bacteria. It is typically the first-line treatment for uncomplicated cases of Bartonellosis. 
• Rifampin is an antibiotic that is commonly used to treat tuberculosis but has also shown efficacy against Bartonella species. It works by inhibiting bacterial RNA synthesis. Rifampin is often used in combination with doxycycline to enhance treatment efficacy and prevent the development of antibiotic resistance. 

Use of <a class="wpil_keyword_link" href="https://medtigo.com/drug/gentamicin" title="gentamicin" data-wpil-keyword-link="linked">gentamicin</a> as replacement therapy

• When treating severe bartonella infections, gentamicin is frequently administered as a second medication. Patients who are receiving gentamicin need to have their renal function checked.  
• In absence of either azithromycin or rifampicin patient can take with combination of gentamicin.   

Use of Intravenous Antibiotics for treatment of endocarditis

• The treatment of Bartonella-associated endocarditis, a rare but serious complication of Bartonellosis, typically involves a combination of antibiotics for an extended period.  
• Given the seriousness of Bartonella endocarditis, intravenous antibiotics are usually administered to ensure adequate penetration into the infected heart valve and bloodstream.  

examination-of-serological-tests

• Bartonellosis can be challenging to diagnose because its symptoms can be like other illnesses.  
• Indication of exposure: Serology tests, such as enzyme-linked immunosorbent assays (ELISA) or indirect immunofluorescence assays (IFA), can detect the presence of specific antibodies against Bartonella henselae in a person’s blood. The presence of these antibodies indicates that the person has been exposed to the bacteria at some point. 
• Confirmatory diagnosis: Serology tests are often used as confirmatory tests for Bartonellosis, especially when the clinical symptoms are suggestive of the disease. A positive serology result, along with a compatible clinical presentation, can provide strong evidence for the diagnosis of Bartonellosis. 

use-of-various-phases-in-management-of-bartonellosis

• In this phase, diagnostic tests, such as serology (blood tests) or polymerase chain reaction (PCR) assays, may be performed to confirm the presence of Bartonella bacteria or detect antibodies against them.  

importance-of-symptom-management

• During the treatment phase, supportive care measures are often implemented to manage specific symptoms associated with Bartonellosis.
• These may include the use of over-the-counter pain relievers to reduce fever and discomfort, warm compresses or analgesic ointments for lymph node swelling.  

Medication

Future Trends

Media Gallary

References

• Bartonellosis – StatPearls – NCBI Bookshelf (nih.gov)