Whole genome sequencing of Mycoplasma hominis strains resistant to ciprofloxacin

Abstract

In order to determine molecular mechanisms of resistance to ciprofloxacin, clinical isolates of Mycoplasma hominis (2 strains) obtained from women with pelvic inflammatory disease were investigated. Whole genome sequencing was performed using a high-performance MiSeq sequencer (Illumina, USA). M. hominis M57 and M45 isolates were found to have the proportion of GC-bases which is typical for this species (27.2%). A high degree of the protein sequences homology of the M57 and M45 isolates has been determined. Phylogenetic analysis showed that the M57 isolate is evolutionarily closer to the PG21 isolate, and M45 is evolutionarily closer to H34. Analysis of the amino acid sequences of gyrA, gyrB, parC and parE genes in M45 and M57 isolates detected that the molecular mechanism of ciprofloxacin resistance is due to the presence of mutational changes in the QRDR of gyrA gene (DNA gyrase subunit A) leading to substitution of serine for leucine at the position 83. No mutations affecting the codons in the QRDR of gyrB, parC and parE genes were detected. Analysis of the gyrA, gyrB, parC and parE genes structure showed a high degree of polymorphism due to the high spontaneous mutations rate. The genomes of M. hominis M45 and M57 isolates found to carry genes of the MATE family efflux pumps, but their role in the development of antimicrobial resistance in M. hominis has not been proved experimentally to date.

Keywords

• mycoplasma hominis
• whole genome sequencing
• resistance
• ciprofloxacin
• gyra
• mutation