| Congresso Brasileiro de Microbiologia 2023 | Resumo: 956-1 | ||||
Resumo:Bovine tuberculosis (BTB), caused by Mycobacterium bovis, is a chronic infectious disease that affects both animals and humans. Non-tuberculous mycobacteria (NTM), a group of mycobacteria found in the environment, can also cause infections, particularly in immunocompromised individuals. The emergence of NTM as a global health concern has raised questions about their role as obligate or opportunistic pathogens in various hosts. In veterinary medicine, the identification of NTM remains challenging due to the complexity of its isolations and molecular detection methods. Importantly, the presence of NTM can interfere with the ante-mortem diagnosis of BTB through skin tests. Furthermore, certain NTM species exhibit natural resistance to conventional tuberculosis treatments. In consequence, tailored therapeutic approaches are needed. Additionally, as Mycobacterium belongs to the Actinomycetales order, similar to Nocardia, there is a possibility of diagnostic interference in BTB detection.
The objective of this study was to compare the genomic sequences of Mycobacterium kansasii, Mycobacterium fortuitum, Mycobacterium porcinum, Mycobacterium novocastrense and Nocardia brevicatena strains isolated from various sources in Argentina, with the reference genome of M. bovis AF2122/97.
The typing of the isolates was performed by gene sequencing of the 16S rRNA, hsp65 and rpoB genes. The complete genome sequencing was conducted using the Illumina platform. Reference-assisted genome assembly was performed using the SPAdes v3.13 tool, resulting in the generation of contigs and scaffolds. The genomes were annotated using the PROKKA. Genetic variations within each genome were analyzed through variant calling using the Snippy tool. Comparison with the reference strain M. bovis AF2122/97 allowed the identification of SNPs, insertions, deletions, and other variations. Identified variants were annotated to assess their impact. The resulting variants were then annotated to assess their potential impact on the genomes. Furthermore, a comprehensive screening of contigs was carried out to detect antimicrobial resistance or virulence genes using the ABRICATE pipeline, which leverages multiple databases, including NCBI, CARD, ARG-ANNOT, Resfinder, MEGARES, VF, and VFDB.
In this study, we identified the genes esxA, esxB, Mv3645c, rpoB, inhA, kstG, pncA, rfpA, and hrcA in all four NTM species (M. kansasii, M. fortuitum, M. porcinum, M novocastrense) and N. brevicatena. Notably, these genes exhibited a high level of conservation across the different species studied. In silico analysis revealed the presence of genes conferring resistance to multiple classes of antibiotics in NTM. Resistance genes to rifampicin, beta-lactams, tetracycline, aminoglycosides, lincosamides, macrolides, streptomycin, fluoroquinolones, and doxycycline were identified. Additionally, genes for resistance to macrolides, beta-lactams, rifampicin, and mycobactins were found in N. brevicatena. These findings highlight the existence of resistance mechanisms against a wide range of antibiotics in NTM and Nocardia. The identification of these resistance genes emphasizes the need for continued surveillance and implementation of control strategies to address antimicrobial resistance in these pathogenic bacteria. This research will contribute to a better understanding of the diversity and clinical significance of NTMs and Nocardia in Argentina, with implications for veterinary and human health.
Palavras-chave: Non-tuberculous mycobacteria (NTM), Nocardia brevicatena, Genome sequencing, Antibiotic resistance, Diagnostic Agência de fomento:Scientific and Technological Research Projects (PICT), Fund for Scientific and Technological Research (FONCyT), National Agency for the Promotion of Research, Technological Development, and Innovation (AGENCIA I+D+i) | |||||