Description of new species of Mycobacterium terrae complex isolated from sewage at the São Paulo zoological park foundation in Brazil

Five mycobacterial isolates from sewage were classified as members of the genus Mycobacterium but presented inconclusive species assignments. Thus, the isolates (MYC017, MYC098, MYC101, MYC123 and MYC340) were analyzed by phenotypical, biochemical, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and genomic features to clarify their taxonomic position. Phenotypic analysis and biochemical tests did not distinguish these isolates from other non-pigmented mycobacteria. In contrast, MALDI-TOF MS analysis showed that isolates were not related to any previously described Mycobacterium species. Comparative genomic analysis showed values of ANI and dDDH between 81.59-85.56% and 24.4-28.8%, respectively, when compared to the genomes of species of this genus. In addition, two (MYC101 and MYC123) presented indistinguishable protein spectra from each other and values of ANI = 98.57% and dDDH = 97.3%, therefore being considered as belonging to the same species. Phylogenetic analysis grouped the five isolates within the Mycobacterium terrae complex (MTC) but in a specific subclade and separated from the species already described and supported by 100% bootstrap value, confirming that they are part of this complex but different from earlier described species. According to these data, we propose the description of four new species belonging to the Mycobacterium genus: (i) Mycobacterium defluvii sp. nov. strain MYC017T (= ATCC TSD-296T = JCM 35364T), (ii) Mycobacterium crassicus sp. nov. strain MYC098T (= ATCC TSD-297T = JCM 35365T), (iii) Mycobacterium zoologicum sp. nov. strain MYC101T (= ATCC TSD-298T = JCM 35366T) and MYC123 (= ATCC BAA-3216 = JCM 35367); and (iv) Mycobacterium nativiensis sp. nov. strain MYC340T (= ATCC TSD-299T = JCM 35368T).

Multi-Approach Characterization of Novel Pyrene-Degrading Mycolicibacterium austroafricanum Isolates Lacking nid Genes

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds that are widespread in the environment, arising from the incomplete combustion of organic material, as well as from human activities involving petrol exploitation, petrochemical industrial waste, gas stations, and environmental disasters. PAHs of high molecular weight, such as pyrene, have carcinogenic and mutagenic effects and are considered pollutants. The microbial degradation of PAHs occurs through the action of multiple dioxygenase genes (nid), which are localized in genomic island denominate region A, and cytochrome P450 monooxygenases genes (cyp) dispersed in the bacterial genome. This study evaluated pyrene degradation by five isolates of Mycolicibacterium austroafricanum using 2,6-dichlorophenol indophenol (DCPIP assay), gas chromatography/mass spectrometry (CG/MS), and genomic analyses. Two isolates (MYC038 and MYC040) exhibited pyrene degradation indexes of 96% and 88%, respectively, over a seven-day incubation period. Interestingly, the genomic analyses showed that the isolates do not have nid genes, which are involved in PAH biodegradation, despite their ability to degrade pyrene, suggesting that degradation may occur due to the presence of cyp150 genes, or even genes that have not yet been described. To the best of our knowledge, this is the first report of isolates without nid genes demonstrating the ability to degrade pyrene.

Evaluation of cleaning and sterilization of liposuction cannulas after intentional contamination with human fat, Mycobacterium abscessus subspecies bolletii and Geobacillus stearothermophilus

BACKGROUND

The complex design of cannulas is a major challenge for reprocessing due to the retention and accumulation of fat residues.

AIM

To evaluate the cleaning of liposuction cannulas and the protective effects of the remaining fat residues on Mycobacterium abscessus subspecies bolletii (MASB) and Geobacillus stearothermophilus inactivation during steam sterilization.

METHODS

In Phase 1, six standard operating procedures (SOP) were evaluated for cleaning of liposuction cannulas. In Phase 2, the sectioned lumens of the liposuction cannulas were contaminated with the largest and smallest volume of human fat found in Phase 1, with the addition of MASB. In Phase 3, the same volumes of human fat from Phase 2 were used to contaminate paper strips containing G. stearothermophilus.

FINDINGS

In phase 1 the residual amount of fat ranged from 6 to 52mg. In phases 2 and 3, the minimum and maximum amounts of fat (6 to 50mg) protected microorganisms during steam sterilization at 134ºC for 1.5 and 3min.

CONCLUSION

Effective cleaning and sterilization of liposuction cannulas intentionally contaminated with human fat, MASB and G. stearothermophilus could not be performed.