FUNCTIONAL PANGENOME ANALYSIS AND GENOME CHARACTERIZATION OF A COLLECTION OF Staphylococcus aureus ISOLATES FROM PATIENTS WITH OSTEOMYELITIS IN ARGENTINA.

SULIGOY CM; LOMBARTE SERRAT, A; DIAZ, R; ROBINSON, DA; BUZZOLA, FR; SORDELLI, DO

Congreso; XIII CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE; 2018

Staphylococcus aureus is a highly prevalent human pathogen that causes osteomyelitis. The aim ofthis study was the analysis of the pangenome and genome characterization of S. aureus isolates frompatients of Argentina with osteomyelitis. S. aureus isolates from 27 patients with chronic and acuteosteomyelitis from 5 different hospitals were sequenced with Illumina MiSeq. Reads were assembledde novo with SPAdes and filtered. The genomes were annotated with Prokka and pangenomeanalysis was performed using Roary. Abricate was used to screen virulence factors and antimicrobialresistance genes. Functional analysis of pangenome was performed using the EggNOG server, usingCOG annotation. Scoary was used to perform the pangenome wide association study.The S. aureus genome mean size was 2,81 Mbp, with an N50 of 1,04 Mbp, an average of 25 contigsper isolate and a 32,82% GC content. An average of 2.812 CDS per genome and 59 tRNA werepredicted. A total of 4.094 different genes were detected and 2.032 of these genes were shared by allisolates (core genome, CG), 486 genes by only one isolate (unique genome, UG) and 1575 geneswere shared from 2 to 26 isolates (shell genome, SF). Metabolism related genes were more frequentin the core genome (38,6%) when compared with shell (7%) and unique genome (8%). In themetabolic category, the CG represented group was mostly aminoacid transport and metabolism(23%), in SF the most represented group was inorganic (26%) and aminoacid (22%) transport and inUG was inorganic ion transport and metabolism with 50% of the total metabolic genes. In genesrelated with cellular process and signaling, 14% were in CG, 9% in SG and 5% in UG. In the categoryassigned to information storage and processing in CG was 17%, 15% in SF and 25% in UG. In thiscategory, in the CG, the most represented group was translation and transciption related proteins(39% and 35%) but in SG and UG the most represented group was replication and recombinationrelated proteins (67 % and 74%), most of them related with transposons and phages. Theuncharacterized proteins or unassigned proteins were 29% in CG, 67% in SG and 60% in UG.Every isolate contained from 63 to 69 characterized virulence genes. 17/27 isolates carried genescoding for resistance to aminoglycosides, 27/27 to fluoroquinolones, 4/27 to erythromycin, 27/27 tochloramphenicol (one including the gene fexa) and 15/27 were MRSA (mecA gene). Pangenomeassociation analysis of virulence and resistance genes information was performed to find genesassociated with acute or chronic infection or with a given hospital. No gene was associated to anyhospital and no gene was associated with chronic or acute infection. In conclusion, the sequenceanalysis of S. aureus isolates from Argentina revealed a conserved core genome, with predominanceof metabolic genes. Functional pangenome analysis is a suitable tool to identify conserved targetgenes for vaccine and drug development.