Genomic characterization of a collection of ST5 Staphylococcus aureus isolates from patients with osteomyelitis.

SULIGOY LOZANO CM; LOMBARTE SERRAT A; DOTTO C; ROBINSON D.A.; SORDELLI DO; BUZZOLA FR

Buenos Aires

Congreso; LXII Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2017

Sociedades de Biociencias.(SAIC/SAI/SAFE)

Staphylococcus aureus is a highly prevalent human pathogen that emerges as one of the most prevalent causative agents of osteomyelitis. The S. aureus genome carries a vast array of genes coding for virulence and evasion factors. The aim of this study was the characterization of a collection of ST5 S. aureus isolates from patients with osteomyelitis through whole genome analysis to detect association between genes and several defined variables. S. aureus ST5 isolates from 19 patients with chronic osteomyelitis from 5 different hospitals in Argentina were sequenced with Illumina MiSeq. Reads were assembled de novo with SPAdes. The genomes were annotated with Prokka and pangenome analysis was performed using Roary. Abricate was used to screen virulence factors and antimicrobial resistance genes. Scoary was used to perform the pangenome wide association study. The S. aureus genome mean of size was 2,86 Mbp, with an N50 of 1,24 Mbp, with an average of 12 contigs per isolate and a 32,83% GC content. An average of 2.628 CDS per genome and 61 tRNA were predicted. A total of 3.443 different genes were detected and 2.307 of these genes were shared by all isolates (core genome). Every isolate contained from 65 to 69 characterized virulence genes. Eight of 19 isolates carried genes coding for resistance to aminoglycosides, 18/19 to fluoroquinolones, 9/19 to erythromycin, 1/19 to chloramphenicol and 12/19 were MRSA (mecA gene). The pangenome wide association study revealed a beta-lactamase associated with only one Hospital. No gene was associated with the other 4 hospitals investigated. No gene was associated with chronic or acute infection. In conclusion, the sequence analysis of closely related S. aureus isolates revealed a conserved core genome. We found a beta-lactamase gene associated with isolates from only one Hospital. The present methodology is a suitable tool to investigate related isolates and identify genes involved in virulence or antibiotic resistance.