Bartonellosis

Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella.^[1] Bartonella cause diseases such as Carrión´s disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.^[2]

Microbiology

Members of the genus Bartonella are facultative intracellular bacteria, alpha 2 subgroup Proteobacteria. The genus comprises:

History of discovery

Carrión's disease

The disease was named after medical student Daniel Alcides Carrión from Cerro de Pasco, Peru. Carrión described the disease after being inoculated at his request with the pus of a skin lesion from patient Carmen Paredes in 1885 by Doctor Evaristo M. Chávez, a close friend and coworker in Dos de Mayo National Hospital. Carrión developed the disease three weeks after the inoculation and kept a meticulous record of clinical symptoms and signs until the disease rendered him incapable of the task and he died at age 28 several weeks later—October 5, 1885. Carrión proved that "Oroya fever" and "Verruga Peruana" were two stages of the same disease, and not two different diseases as was thought at the time. Subsequently, 23 subspecies of Bartonella were discovered. His work did not result in a cure immediately, but his research started the process. Peru has named October 5 as "Peruvian Medicine Day" in his honor.

Peruvian microbiologist Alberto Barton discovered the causative bacterium in 1905, but his results were not published until 1909. Barton originally identified them as "endoglobular" structures, bacteria living inside red blood cells. Until 1993, the Bartonella genus contained only one species; there are now 23 identified species, all of them within the family of Bartonellaceae.^[3]

Cat-scratch disease

In 1988, English et al. ^[4] isolated and cultured a bacterium that was named Afipia felis in 1992 after the team at Armed Forces Institute of Pathology (AFIP)that discovered it. This agent was considered the etiologic agent of Cat-scratch Disease (CSD) but further studies failed to support this conclusion. Serologic studies associated CSD with Bartonella henselae, reported in 1992. In 1993 Dolan ^[5] isolated Rochalimae henselae (now called Bartonella henselae) from lymph nodes of patients with CSD.

Bartonella spp. is commonly treated with antibiotics including azithromycin, based on a single small randomized clinical trial. Treatment may take up to one year to completely eliminate the disease. CSD often resolves spontaneously without treatment.^[6]

Trench fever

Detailed descriptions of the disease were reported in soldiers during the First World War. It is also known as five-day fever, quintan fever, Wolhinie fever and "urban trench fever", because it occurs in homeless people and alcoholics .^[7]

Epidemiology

Carrión's disease, or Oroya fever, or Peruvian wart is a rare infectious disease found only in Peru, Ecuador, and Colombia.^[8] It is endemic in some areas of Peru,^[9] is caused by infection with the bacterium Bartonella bacilliformis, and transmitted by sandflies of genus Lutzomyia.

Cat scratch disease occurs worldwide. Cats are the main reservoir of Bartonella henselae (etiologic agent), and the bacterium is transmitted to cats by the cat flea Ctenocephalides felis.^[10] Infection in cats is very common with a prevalence estimated between 40-60%, younger cats being more commonly infective. Cats usually become immune to the infection, while dogs may be very symptomatic. Humans may also acquire it through flea or tick bites from infected dogs, cats, coyotes, and foxes.

Trench fever, produced by Bartonella quintana infection, is transmitted by the human body louse Pediculus humanus corporis. Humans are the only known reservoir.^[11] Thorough washing of clothing may have help to interrupt the transmission of infection.

A possible role for ticks in transmission of Bartonella species remains to be elucidated; in November 2011, Bartonella rochalimae, B. quintana, and B. elizabethae DNA was first reported in Rhipicephalus sanguineus and Dermacentor nitens ticks in Peru.^[12]

Pathophysiology

In mammals, each Bartonella species is highly adapted to its reservoir host as the result of intracellular parasitism and can persist in the bloodstream of the host. Intraerythrocytic parasitism is only observed in the acute phase of Carrión´s disease. Bartonella also have a tropism for endothelial cells, observed in the chronic phase of Carrión´s disease (also known as Verruga Peruana) and bacillary angiomatosis. Pathological response can vary with the immune status of the host. Infection with Bartonella henselae can result in a focal suppurative reaction (CSD in immunocompetent patients), a multifocal angioproliferative response (bacillary angiomatosis in immunocompromised patients), endocarditis or meningitis.

Clinical manifestations

Carrión's disease

Patients can develop two clinical phases: an acute septic phase and a chronic eruptive phase associated with skin lesions.^[13] In the acute phase (also known as Oroya fever or Fiebre de la Oroya), Bartonella bacilliformis infection is a sudden, potentially life-threatening infection associated with high fever and decreased levels of circulating red blood cells (i.e., hemolytic anemia)and transient immunosuppression.Bartonella bacilliformis is considered the most deadly Bartonella to date, with a death rate of up to 90% during the acute phase, which typically lasts two-to-four weeks. Peripheral blood smears show anisomacrocytosis with many bacilli adherent to red blood cells. Thrombocytopenia is also seen and can be very severe. Neurologic manifestations (neurobartonellosis) are altered mental status, agitation, or even coma, ataxia, spinal meningitis or paralysis. It is seen in 20% of patients with acute infection, in which case the prognosis is very guarded with an about 50% mortality. The most feared complication is overwhelming infection mainly by Enterobacteriacea, particularly Salmonella(both S. typhi and S.non-typhi, as well as reactivation of Toxoplasmosis and other opportunistic infections .

The chronic manifestation—Verruga Peruana—consists of a benign skin eruption with raised, reddish-purple nodules (angiomatous tumours). The bacterium can be seen microscopically, if a skin biopsy issilver stained (the Warthin–Starry method).

Cat scratch disease

Cat scratch disease is due to an infection by Bartonella henselae and manifests as gradual regional lymph nodes enlargement (axilla, groin, neck) which may last 2–3 months or longer and a distal scratch and/or red-brown skin papule (not always seen at the time of the disease). The enlarged lymph node is painful and tender. The infection is self-limited.^[14] The lymph nodes may suppurate, and most patients can remain afebrile or asymptomatic. Other presentations include fever of unknown origin (particularly in children), Parinaud's oculoglandular syndrome, encephalopathy and neuroretinitis.^[15][16]

Bartonella henselae can be associated with bacteremia, bacillary angiomatosis, and peliosis hepatis in HIV patients, and bacteremia and endocarditis in immunocompetent and immunocompromised patients.^[17] Symptoms may include fatigue, headaches, fever, memory loss, disorientation, insomnia, and loss of coordination. The bacteria blocks the normal immune response by suppressing the NF-κB apoptosis pathway.^[18] Disease progression may be accelerated if the host is subsequently infected by an immune suppressing virus such as Epstein Barr virus.^[19]

Bacillary angiomatosis

Bartonella henselae and Bartonella quintana can cause bacillary angiomatosis, a vascular proliferative disease involving mainly the skin, and other organs. The disease was first described in Human Immunodificiency Virus (HIV)patients and organ transplant recipients.^[20] Severe, progressive and disseminated disease may occur in HIV patients.^[21] Differential diagnosis include Kaposi´s sarcoma, pyogenic granuloma, hemangioma, Verruga peruana, subcutanous tumors. Lesions can affect bone marrow, liver, spleen or lymph nodes.

Peliosis hepatis

Bartonella henselae is the etiologic agent for peliosis hepatis, which is defined as a vascular proliferation of sinusoid hepatic capillaries resulting in blood-filled spaces in the liver. in HIV patients and organ transplant recipients. Peliosis hepatis can be associated by peliosis of the spleen, as well as bacillary angiomatosis of the skin in HIV patients.^[22]

Trench fever

Trench fever, also known as 5-day fever or quintan fever is the initial manifestation of Bartonella quintana infection. Clinical manifestations range from asymptomatic infection to severe illness. Classical presentation include a febrile illness of acute onset, headache, dizziness and shin pain. Chronic infection manifestation include attacks of fever and aching in some cases and persistent bacteremia in soldiers and homeless people.^[23]

Treatment

Treatment of infections caused by Bartonella species.^[24][25]

While some authorities recommend the use of azithromycin,^[26] it's difficult to gauge what, if any significant benefit, is afforded given the often self-limiting course in patients with intact immune function.

References

External links

• Oroya fever
• Human Bartonellosis caused by Bartonella bacilliformis