The puzzle of the evolutionary natural history of tuberculosis.

Several pieces of the puzzle of the natural history of tuberculosis are assembled in this review to illustrate the potential reservoirs and sources of the Mycobacterium tuberculosis complex (MTBC) mycobacteria, their transmission to animals and humans, and their fate in populations, in a co-evolutionary perspective. Millennia-old companions of mammalian and human populations, MTBC are detected in the soil, in which they infect and survive within vegetative amoebae and cysts, except for Mycobacterium canettii. Never detected in the sphere of plants, they are transmissible by transcutaneous, digestive and respiratory routes and cause an infection of the lymphatic system with secondary dissemination in most tissues, in which they determine a specific and non-pathognomonic granulomatous inflammatory reaction; in which MTBC survives in dormant form irrespective of MTBC species and mammalian species; indicating that the current epidemiology in mammalian populations is essentially governed by the probabilities of contact between mammalian species and MTBC species. Individual variabilities in clinical expression of tuberculosis are related to MTBC species, strain and inoculum; host genetic factors; acquired modulations of the inflammatory response; and probably human microbiota. This review of the literature suggests an evolutionary natural history of telluric environmental mycobacteria, satellites of unicellular eukaryotes, transmissible to mammals via the digestive and then respiratory tracts, in which they determine a fatal contagious infection that is primarily lymphatic and a quiescence-mimicking encysted form. This review opens perspectives for microbiological and translational medical research.

Microscopic detection of bacillus Calmette-Guérin mycobacteria in bladder biopsy using fluorescence in situ hybridization: Détection microscopique des Bacilles biliés de Calmette et Guérin (BCG) dans une biopsie vésicale par hybridation in situ en fluorescence.

Intravesical instillation of Bacilli Calmette Guérin (BCG) as a superficial bladder cancer treatment is generally well tolerated, but local or systemic complications may occur, some of which may be life-threatening. Following the suspicion of post-BCG cystitis in a 72-year-old man with a history of urothelial carcinoma treated by intravesical BCG instillation, we used fluorescence in situ hybridization (FISH) targeting the rpoB gene of the Mycobacterium tuberculosis complex to detect Mycobacterium bovis BCG in paraffin-embedded bladder biopsy sections. FISH yielded specific detection of BCG mycobacteria in the bladder biopsy section, appearing as red-fluorescent bacilli. Treatment with rifampicin, ethambutol and isoniazid is then initiated in combination with corticosteroid therapy.

Leprosy in French Polynesia.

Leprosy is a neglected endemic infectious disease in the Pacific region. In French Polynesia (FP), leprosy is no longer a public health problem at the national level, defined by the World Health Organization as a prevalence rate below 1 case per 10,000 population. However, even if its incidence has dramatically declined in FP in the last decades, leprosy is still endemic at a low level. Here we present a case of leprosy in a 34-year-old man from FP diagnosed in 2018. Clinical and microbiologic examinations, including fluorescence in-situ hybridization, led to the diagnosis of a multibacillary leprosy, and multidrug therapy was initiated. There is a need to maintain leprosy surveillance and trained medical staff for the detection and treatment of new cases.