Protective Efficacy of BCG Vaccine against Mycobacterium leprae and Non-Tuberculous Mycobacterial Infections

Abstract

The genus mycobacterium includes several species that are known to cause infections in humans. The microorganisms are classified into tuberculous and non-tuberculous based on their morphological characteristics, defined by the dynamic relationship between the host defenses and the infectious agent. Non-tuberculous mycobacteria (NTM) include all the species of mycobacterium other than the ones that cause tuberculosis (TB). The group of NTM contains almost 200 different species and they are found in soil, water, animals—both domestic and wild—milk and food products, and from plumbed water resources such as sewers and showerhead sprays. A systematic review of Medline between 1946 and 2014 showed an 81% decline in TB incidence rates with a simultaneous 94% increase in infections caused by NTM. Prevalence of infections due to NTM has increased relative to infections caused by TB owing to the stringent prevention and control programs in Western countries such as the USA and Canada. While the spread of typical mycobacterial infections such as TB and leprosy involves human contact, NTM seem to spread easily from the environment without the risk of acquiring from a human contact except in the case of M. abscessus in patients with cystic fibrosis, where human transmission as well as transmission through fomites and aerosols has been recorded. NTM are opportunistic in their infectious processes, making immunocompromised individuals such as those with other systemic infections such as HIV, immunodeficiencies, pulmonary disease, or usage of medications such as long-term corticosteroids/TNF-α inhibitors more susceptible. This review provides insight on pathogenesis, treatment, and BCG vaccine efficacy against M. leprae and some important NTM infections.

Good practices in the rearing and maintenance of zebrafish (Danio rerio) in Brazilian laboratories

“…It has already been reported that the BCG (Bacillus Calmette-Guérin) vaccine has been shown to reduce the lethality of M. marinum in zebrafish (131) . Furthermore, the BCG vaccine can provide crossprotection against several Mycobacterium species in zebrafish colonies (132) . This shows that the BCG vaccine has a broad protective spectrum with respect to bacterial species and potential host species present in a zebrafish facility.…”

Boas práticas na criação e manutenção de zebrafish (Danio rerio) em laboratório no Brasil

“…Já foi reportado que a vacina BCG (Bacillus Calmette-Guérin) se provou capaz de reduzir a letalidade de M. marinum sobre zebrafish (131) . Além disso, a vacina BCG é capaz de proporcionar alguma proteção cruzada contra várias espécies de Mycobacterium presentes em colônias de zebrafish (132) . Isso mostra que a vacina BCG tem um amplo espectro protetivo no que diz respeito às espécies de bactérias e às espécies de hospedeiros potenciais presentes em um biotério de zebrafish.…”

Mycobacterium abscessus: It’s Complex

“…This fact was confirmed through the epidemiological evidence suggesting that BCG vaccination decreases the risk of developing NTM-PD [ 162 ]. It was suggested that BCG vaccination can be used as either a therapeutic or prophylactic vaccine against M. abscessus -PD [ 161 , 163 ]. BCG, as a live-attenuated vaccine, induces T-cell expansion important for intracellular pathogens like M. abscessus [ 161 , 164 ].…”