Mycoplasma agassizii Multilocus Sequence Typing Using Nanopore Sequencing: Insights Into Genetic Diversity and...

Area of Science:

• Veterinary Microbiology
• Genetics
• Conservation Biology

Background:

• Mycoplasma agassizii causes upper respiratory tract disease (URTD) in tortoises, leading to population declines.
• Limited tools exist for strain-level identification and epidemiological tracking of M. agassizii.

Purpose of the Study:

• To develop and validate a Multilocus Sequence Typing (MLST) scheme for characterizing M. agassizii.
• To assess the genetic diversity and population structure of M. agassizii in Italy and Portugal.

Main Methods:

• Developed an MLST scheme using eight housekeeping genes (uvrB, tpiA, gyrB, efTu, rpoB, uvrA, gmK, atpG).
• Employed Nanopore sequencing for characterizing M. agassizii isolates from 127 tortoise samples.
• Analyzed 15 positive isolates to determine sequence types (STs) and genetic diversity.

Main Results:

• 73 out of 127 samples (57.5%) were positive for M. agassizii.
• 15 isolates yielded 14 distinct sequence types (STs), indicating high genetic diversity.
• Four loci (uvrB, gyrB, rpoB, gmK) were sufficient for ST discrimination.
• The population structure suggests partial clonality with evidence of recombination (I_a = 0.2246).

Conclusions:

• The developed MLST scheme is effective for strain-level identification and epidemiological tracking of M. agassizii.
• High genetic diversity was observed, irrespective of geographic origin or tortoise species.
• Further studies across diverse hosts are needed to link strains with disease outcomes for improved conservation and URTD control.