Decrypting the environmental sources of Mycobacterium canettii by high-throughput biochemical profiling

Abstract

Mycobacterium canettii is a smooth bacillus related to the Mycobacterium tuberculosis complex. It causes lymph nodes and pulmonary tuberculosis in patients living in countries of the Horn of Africa, including Djibouti. The environmental reservoirs of M . canettii are still unknown. We aimed to further decrypt these potential reservoirs by using an original approach of High-Throughput Carbon and Azote Substrate Profiling. The Biolog Phenotype profiling was performed on six clinical strains of M . canettii and one M . tuberculosis strain was used as a positive control. The experiments were duplicated and authenticated by negative controls. While M . tuberculosis metabolized 22/190 (11%) carbon substrates and 3/95 (3%) nitrogen substrates, 17/190 (8.9%) carbon substrates and three nitrogen substrates were metabolized by the six M . canettii strains forming the so-called corebiologome. A total at 16 carbon substrates and three nitrogen substrates were metabolized in common by M . tuberculosis and the six M . canettii strains . Moreover, at least one M . canettii strain metabolized 36/190 (19%) carbon substrates and 3/95 (3%) nitrogen substrates for a total of 39/285 (13%) substrates. Classifying these carbon and nitrogen substrates into ten potential environmental sources (plants, fruits and vegetables, bacteria, algae, fungi, nematodes, mollusks, mammals, insects and inanimate environment) significantly associated carbon and nitrogen substrates metabolized by at least one M . canettii strain with plants ( p = 0.006). These results suggest that some plants endemic in the Horn of Africa may serve as ecological niches for M . canettii . Further ethnobotanical studies will indicate plant usages by local populations, then guiding field microbiological investigations in order to prove the definite environmental reservoirs of this opportunistic tuberculous pathogen.

Cross pollination and inflorescence branching in the presence of Mycoacterium canetti in Floral microbiome of Syzygium aromaticum (L) Merr. and Perry

“…Present study assumes Mycobacteria canettii, highly recombinogenic and diversi ed tubercle bacilli 13 14 , is present abundant in Syzygium aromaticum may be by both horizondal and vertical transmission. Biolog phenotype pro ling to understand environmental reservoirs showed carbon and nitrogen substrates of plant were signi cantly metabolized by M. canettii 15 and a fully active cellulase enzyme is encoded in genome, which suggest plants may serve as ecological niches for M. canettii. It can also utilize rhamnose 16 which is abundant in Syzygium aromaticum 17 .…”

Mycobacterium canettii Tuberculosis Lymphadenopathy in a 3-Year-old Child

“…3 Endemic plants in the countries of the Horn of Africa (as Catha edulis whose leaves are chewed for their psychotropic properties) have also been suspected because they can provide carbon and nitrogen substrates metabolized by M. canettii . 4 In addition, this bacterium grows faster at temperatures below 37°C and has numerous recombination and lateral gene acquisition events, a common feature of environmental bacteria which have to be well-equipped to colonize different ecological niches and to compete with other different microorganisms. 1,5…”

Molecular surveillance of tuberculosis-causing mycobacteria in wastewater

“…These include M. bovis , the causative agent of tuberculosis mainly in animals. M. bovis causes disease in humans because of its zoonotic capacity, but it is mainly the agent of animal and particularly bovine TB infections (bovines being the main maintenance host of the bacterium) ( Walter et al., 2012 ; Howell et al., 2019 ; Nugent et al., 2017 ; Inlamea et al., 2020 ), Mycobacterium africanum , the causative agent of human tuberculosis (mainly in Western Africa) ( Gehre et al., 2016 ; Tientcheu et al., 2016 ) and Mycobacterium canetti isolated in the Horn of Africa ( Loukil et al., 2019 ) and reported in human infections, however, its natural reservoir, host range, and mode of transmission still remains debatable. Other members of this group are M. microti , M. caprae, M. pinnipedii and M. mungi, usually associated with animal infections with possible transmission to humans.…”