BARTONELLADr.Jayaprada

INTRODUCTION Bartonella are very small Gram negative

bacilli transmitted by arthropods which invade mammalian endothelial cells and blood cells.

Human pathogenic strains are B. bacilliformis, B. quintana and B. henselae.

Bartonella ( including some spp formerly known as Rochalimaea) is a genus of short, Facultative intracellular, pleomorphic, Gram negative coccobacilli/bacillary rods.

TAXONOMY Bartonella belongs to: CLASS: Alphaproteobacteria. ORDER: Rhizobiales. FAMILY: Bartonellaceae. GENUS: Bartonella. Family Bartonellaceae contains two genera: Bartonella and Grahamella. Members of genus Grahamella do not infect

humans. The genus Bartonella consists of 22 species.

CONDITIONS CAUSED BY BARTONELLA SPP BARTONELLA SPP CONDITION B.bacilliformis-CARRION’S disease (Oroya fever/

Verruga peruana. B. quintana Trench fever, Bacillary

angiomatosis,Endocarditis, Chronic bacteremia. B.henselae Cat scratch disease, Endocarditis,

Myocarditis, Chronic bacteremia, Bacillary angiomatosis, Neuroretinitis, Status epilepticus, Arthritis , Peliosis hepatis, prolonged fever, weight loss, Glomeronephritis, osteomyelitis……

B.clarridgeiaeCSD ( serological only). B.elizibathae Endocarditis. B.vinsonii berkhoffi Endocarditis.

B.grahamii Uveitis, Bilateral retinal artery occlusion.

B.vinsonii arupensis fever, confusion, valvu

lopathy B. washoensis Cardiopathy

(myocarditis). Recently, Candidatus Bartonella

washoensis and Candidatus Bartonella melophagi were respectively isolated from aortic valve of 1 patient with culture-negative endocarditis

RESERVOIR VECTOR

B. quintana Human Human Body Louse

B. bacilliformis Sand Flies

B. henselae Feline Cat flea (Ctenocephalides felis)

B. elizabethae Rat

B. washoensis Gr. Squirrel

B. vinsonii arup Mice Deer tick (Ixodes scapularis)

B. vinsonii berk. Canine Ticks

B. koehlare Cat Cat flea (Ctenocephalides felis)

B. clarridgeae Cat flea (Ctenocephalides felis)

B. alsatica Rabbit

BARTONELLA SP Organism Resevoir Transmission Disease(s)

B. bacilliformis ?humans Sand flies Carrion's disease

B. quintana ?humans Human body Trench fever, relapsing

?rodents louse fever, bacteremia, endocarditis, bacillary angiomatosis,

lymphadenopathy

B. henselae Domestic Cat bites or Cat-scratch disease, cats scratches bacteremia, endocarditis, bacillary angiomatosis, peliosis hepatitis

• Bartonella currently includes 22 species, only 5 cause human disease

VECTORS

B. bacilliformis - sandfly, Lutzymia verrucarum

B. quintana - human body louse, Pediculus humanus humanus

B. henselae - cat flea, Ctenocephalides felis

B.BACILLIFORMIS

INTRODUCTION B. bacilliformis is the causative agent of Oroya

fever. An acute febrile illness consisting of severe

anemia. This condition was first identified in the

mountainous parts of Peru in 1870 during the laying of railway lines from Lima to Oroya in Peru.

The outbreak of Oroya fever killed 1000 of workers associated with this railway project.

Some of the survivors developed nodular ulcerating skin lesions, called verruga peruana.

Daniel Carrion inoculated himself with material from verruga and developed Oroya fever from which he died.

Oroya fever is therefore also known as Carrion's disease.

HISTORICAL HIGHLIGHTS

PERUVIAN ANDES B. BACILLIFORMIS

Source: www.earlham.edu

MORPHOLOGY B. bacilliformis are short, Gram-negative

coccobacilli measuring 0.3-0.5 X 1.0-1.7µ. They are motile by the presence of as many

as 10 flagella at one pole of the bacteria. They are aerobic and require an optimum pH

of 7.8 and optimum temperature of 25-28°C for their growth.

It can grow in semisolid nutrient agar with 10% rabbit serum and 0.5% hemoglobin.

Growth is slow and takes about 10 days. No animal reservoir known. Humans remain

bacteremic for months ( 10%).

PATHOGENESIS B. bacilliform is causes Oroya fever transmitted

by sandflies--Lutzymia verrucarum. The incubation period is 3 weeks to 3 months. Patient develops fever, severe headache and

chills, followed by severe anaemia due to destruction of erythrocytes by the organism.

Several weeks after recovery, patient may develop nodular lesions on exposed part of the body. These nodules may become secondarily infected producing ulcers, this condition is known as Verruga peruana.

PATHOGENESIS B bacilliformis, which uses a polar flagellum

for motility, adheres to and invades RBCs. After entry, the organism replicates in vacuoles.

B bacilliformis also makes an endothelial cell–stimulating factor that causes proliferation of both endothelial cells and blood vessels.

Most spp of Bartonella are biochemically inert except for the production of peptidases.

CLINICAL SIGNIFICANCE OROYA FEVER : It is characterized by

progressive, severe & febrile anemia with intravascular hemolysis associated with the presence of B.bacilliformis in the RBC’s. Mortality is 40-90% in pre antibiotic era.

Verruga peruana: It is characterized by nodular angioproliferative cutaneous lesions called Verruga peruana.

LAB DIAGNOSIS Organisms can be demonstrated in blood

smears stained by Gimenez stain. They are seen in the cytoplasm as well as adhering to cell surfaces.

(ii) It can be grown on nutrient agar containing 10% rabbit serum and 0.5% haemoglobin. (iii) Guinea pig inoculation leads to verruga

peruana but not Oroya fever.

TREATMENT AND PROPHYLAXIS Penicillin, streptomycin, tetracycline, and

chloramphenicol are effective for the treatment of B. bacilliformis infection.

Use of insecticides such as DDT to kill the sand fly prevents transmission of the disease.

BARTONELLA QUINTANA

DESCRIPTION OF THE GENUS B. quintana is a small Gram negative

bacillus measuring 0.3 - 0.5µ x 1.0 - 1.7µ. It does not possess flagella. It may show twitching movement on wet

mounts associated with the expression of TAAs-Trimeric Autotransporter Adhesin.

TAAs are responsible for cytoadherence & may mediate specific interactions with extracellular components and endothelial cells.

DESCRIPTION OF THE GENUS

It grows on rabbit or sheep blood agar. Optimum temperature for growth is 35°C in 5% CO 2 .

Colonies are smooth, flat, shiny & do not pit the agar and appear after 14 days in primary culture.

It was formerly called Rochalimaea quintana.

It causes trench fever.

HISTORICAL HIGHLIGHTSWorld War I

B. QUINTANA B. quintana was earlier known as

Rochalimaea quintana as a causative agent of trench fever or 5-day fever.

This condition was first recognized in the soldiers fighting in trenches in Europe during the First World War.

The causative agent was earlier identified as a rickettsia and named Rickettsia quintana because it caused a 5-day fever (from quintana, means fifth), a synonym for trench fever.

Currently, it has undergone further taxonomical classification and has been reclassified as Bartonella quintana.

DIFFERENCES B/N ROCHALIMAEA & RICKETTSIAE

Rochalimaea differs from rickettsiae in the following respects:

(i) It occurs extracellularly in the arthropod host.

(ii) It grows poorly in the yolk sac of chick embryo.

(iii) It can be grown on blood agar. (iv) Convalescent sera from patients do not

react with rickettsial or Proteus antigens (Weil-Felix reaction).

(v) It does not cause experimental infection in any of the common laboratory animals.

Only monkeys can be infected besides man and the louse.

PATHOGENESIS Trench fever is an exclusively human disease and

no animal reservoir is known. It is transmitted by the body louse (Pediculus humanus humanus).

The lice become infectious 5-9 days after feeding on a trench fever patient, after which the lice remain infectious throughout their life and excrete organisms in their feces.

The infected lice when bite a new host defecate on surface of the skin. This feces when comes in contact with minor scratches or abrasions on the surface of the skin, the bacteria present in the feces enter the skin and initiate the infection.

CLINICAL SIGNIFICANCE Incubation period -- 14-30 days. The condition can vary from asymptomatic

to symptomatic infection. Severe headache, fever (giving the name of

the disease as 5-day fever), chills, weakness, and severe pain in the back and legs, abdominal pain, restlessness, insomnia.

Several cases of endocarditis have been associated with B.quitana infection.

In HIV infected persons, bacteremia results in recurrent fever, headache, hepatomegaly.

B.quitana & B.henselae are the 2 Bartonella spp involved in the aetiology of bacillary angiomatosis.

CLINICAL SIGNIFICANCE Bacillary angiomatosis also called epitheloid

angiomatosis. It is a vasoproliferative disease characterized

by violaceous/ colorless papular and nodular lesions.

It clinically suggest Kaposi's sarcoma & histologically resemble epitheloid haemangiomas.

When visceral organs are involved,the condition is called Bacillary peliosis hepatis, splenic peliosis, systemic bacillary angiomatosis.

Subcutaneous and lytic lesions in the bone are associated with B .quintana infection.

Trench fever is an exclusively human disease. No animal reservoir.

The disease is transmitted from humans to humans by the human body louse vector.

Trench fever cases have been identified in some homeless persons living in unsanitary conditions in the USA.

LAB DIAGNOSIS Isolation of the bacteria from patient's

blood on blood agar after 2 weeks of incubation.

B. quintana can be isolated by allowing healthy lice to feed upon the patient and the organisms may be detected in the gut of these lice (xenodiagnosis).

Weil-Felix test used for diagnosis of rickettsial infection is negative in trench fever.

PCR has also been used for detection of B. quintana in the tissues.

TREATMENT The condition can be treated with gentamicin

alone or with erythromycin.

BARTONELLA HENSELAE

MORPHOLOGY B. henselae is a small Gram negative bacillus

measuring 2.0-2.5 X 0.5-0.6µ. Like other Bartonella species, it can grow on

chocolate agar or Columbia agar supplemented with 5% sheep or rabbit blood.

B. henselae produces 2 morphological types of colonies:

1. Irregular, raised,rough, dry white cauliflower-like colonies.

2.Small, circular, tan & moist, tending to pit the agar and adhere to the agar after 5-15 days of incubation at 35-37°C in the presence of 5% CO 2 .

Presence of B. henselae) arrow) within naturally infected cat erythrocytes, as seen by confocal microscopy. Natural History of Bartonella Infections (an Exception to Koch’s Postulate) CVI, 2002

FELINE INFECTIONS

ErythrocytesFirm bacterial adhesion Internalization

Membrane-bound compartments

Bacteria replicate within erythrocytesCirculate in the bloodstream (weeks to

months) Long-lasting intraerythrocytic infection Specific adaption to the mode of

transmission

HUMAN INFECTIONS Vascular endothelial cells

Monocytes/macrophages Immunocompenent host

Self-limiting CSDSwollen lymph nodes and fever

Immunocompromised hostBacilliaryangiomatosis-peliosis (BAP)Tumour-like vasoproliferative lesions

Immunocompetent human hostSelf-limiting CSD, swollen lymph nodes and

fever Immunocompromised human host

Bacillary angiomatosis-peliosis (BAP)Tumor-like vasoproliferative lesion

CATSCRATCH DISEASE

EPIDEMIOLOGY

Worldwide distributionPrevalence in warm/humid climates

~ 20,000 cases annually in US80% under the age of 20yrs

30% of domestic cats are infected

PATHOGENESIS Endothelial Cell Invasion and Colonization: Human umbilical endothelial cells (HUVECs)

Bacterial adhesion and invasion Actin-dependant mechanisms

Intracellular membrane-bound compartments B. henselaeinfection leads to:

Secretion of vascularproliferative compounds Inhibition of host cell apoptosisHost cell proliferation

BARTONELLA-CONTAINING VESICLES (BCVS)

Conventional phagocytosis Bacteria reside in membrane-bound

intracellular compartments24hrs post infection

BCVs do not mature into phagosomesProtects intracellular bacteria from degradationSite of bacterial replication

HUVECS INFECTED WITH B. HENSELAE

Kyme, 2005

BCVS IN HUVECS B. henselaedelays fusion of BCVs with

lysosomesEndocytic markers (LAMP1 and EEA1)

Phagosome maturation controlled by active modulation of host cell

Bacterial surface adhesion protein, BadA prevents phagocytosis

B. henselaehas an alternative cell entry mechanism

DISTRIBUTION OF ENDOCYTIC MARKERS IN HUVECS INFECTED WITH B. HENSELAE

A) Stained with TR dextran

B) LysoTracker Red

C) LAMP1

D) EEA1

E) TfR

Intracellular bacteria are green (FITC) and extracellular bacteria appear blue (FITC+Cy5).

Intracellular B. henselae(green) that co-localize with intracellular markers (red) appear yellow.

Normal phagosome maturation was confirmed by strong accumulation of LAMP1 (green).

INVASOME-MEDIATED CELL ENTRY Dependent on the VirB/VirD4 type four

secretion system Cell surface bacterial aggregates Host cell membrane protrusions engulf

bacterial aggregates Internalization of bacterial aggregates Specific mechanism for endothelial cells

colonization in vivo Characteristic bacterial aggregates found

in bacillary angiomatosis lesions In association with proliferating endothelial

cells

STAGES OF INVASOME-MEDIATED INTERNALIZATION

SCANNING ELECTRON MICROSCOPY ANALYSIS OF INVASOME-MEDIATED INVASIONS OF HUVECS INFECTED WITH B. HENSELAE

The formation (A,B), engulfment (C,D) and internalization (E,F) of a bacterial aggregate represent the stages in invasome-mediated invasion.