Actinomadura welshii sp. nov., a New Mycetoma Agent in Mexico

TL;DR

Scientists discovered a new species of Actinomadura, a bacteria causing mycetoma, in Mexico using DNA sequencing.

Contribution

A new Actinomadura species, Actinomadura welshii, was identified and named through whole-genome sequencing.

Findings

One isolate, LIID-AQ337, was found to belong to a new Actinomadura species.

Whole-genome sequencing revealed a genome of 8,163,638-bp in 22 contigs.

Comparative analysis confirmed the isolate's distinct genomic identity.

Abstract

Actinomadura isolates obtained from seven human mycetoma cases in Mexico were characterized using nucleotide sequence analysis of a portion of the small subunit ribosomal RNA gene. Most isolates were identified as Actinomadura madurae. However, one isolate, LIID-AQ337, showed inconclusive results. To determine its identity, genomic DNA from LIID-AQ337 was subjected to whole-genome sequencing using both short- and long-read sequencing, resulting in a genome of 8,163,638-bp spread in 22 contigs. Comparative analysis against currently available genomes of other Actinomadura species suggested that LIID-AQ337 belongs to a new Actinomadura species. We propose to name it Actinomadura welshii sp. nov in honor of Oliverio Welsh, a Mexican dermatologist dedicated to mycetoma studies in Mexico.

Mycetoma is still a neglected infectious disease present in Mexico. The diagnosis and identification of the etiological agents have relied on the use of conventional methods for decades. The application of modern DNA-based molecular biology methods has allowed us to identify the etiological agents with similar microscopic and histopathologic appearances. Since mycetoma is caused by many fungal and bacterial agents, they may share certain biological characteristics that enable them to grow in the human host. Comparative genomic analysis may help us study these otherwise cryptic organisms. In this work, we identify a new Actinomadura species from a human mycetoma case and analyze its genomic composition through whole-genome analysis.

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