Quantitative analysis of proliferation and excretion of Bartonella quintana in body lice, Pediculus humanus L.

Although body louse is a well-known vector of trench fever, the growth kinetics of Bartonella quintana in body lice has not been fully understood. We performed a quantitative analysis of bacterial multiplication rate. B. quintana started proliferation in body lice 4 days after ingestion and was constantly excreted in the feces for at least 3 weeks. The number of bacteria in feces reached the maximum 10(7)/louse per day on Day 15. The doubling time of B. quintana estimated from logistic regression formula was 21.3 hours. Scanning electron microscopy showed the presence of bacterial masses in feces. Immunofluorescent study using specific monoclonal antibody confirmed identification of B. quintana. Such an explosive multiplication rate and active excretion of B. quintana from the body lice could be related to epidemics of trench fever in developed countries.

Bartonella quintana invades and multiplies within endothelial cells in vitro and in vivo and forms intracellular blebs.

Bartonella quintana, the aetiologic agent of trench fever, has recently been implicated in culture-negative endocarditis and bacteraemia amongst homeless people. B. quintana is a fastidious slow-growing organism. A tissue culture system of human endothelial cells was developed in which B. quintana grew intracellularly. Observation of the different steps during infection of these cells demonstrated that the bacteria adhered to and penetrated the cells by phagocytosis. During the preadherence stage, most bacteria exhibited surface appendages that resembled those described for Salmonella typhimurium and which may mediate specific interactions between the eucaryotic cell and the bacterium. Soon after the engulfment step, the bacterium appeared in a cell vacuole where it multiplied, giving the typical aspect of morulae which has also been reported with Ehrlichiae or Chlamydiae. In older cultures, the coexistence of bacteria and huge quantities of vesicle-like structures in the same vacuole were noted. These vesicle-like structures were also found with agar-grown bacteria and were identified as membrane blebs. Microscopic observation of heart valves from B. quintana endocarditis patients demonstrated the intracellular location of B. quintana in vivo. This intracellular location of B. quintana should now be considered in further studies on the pathogenesis of the diseases it causes.

[Bacillary angiomatosis]. / Bazilläre Angiomatose.

Bacillary angiomatosis (BA) is a rare infectious disease usually associated with HIV infection. Recent molecular biologic investigations confirm that both Rochalimaea henselae and Rochalimaea quintana can cause BA. The bacteria can be identified by Warthin-Starry staining and electron microscopy. The typical clinical signs are solitary or multiple dermal or subcutaneous nodules. Bone, liver, spleen and other organs may also be involved. We describe the clinical and histological features of a 39-year-old HIV-infected patient with cutaneous and bony lesions of BA. All manifestations of BA disappeared during therapy with erythromycin.