P094

1:University Medical Center Groningen; 2:University of Groningen

Mycobacterium fortuitum group (MFG) comprises rapidly growing species, generally of low virulence. However, invasive infections have been reported. The ESX-1 gene complex is a system for excretion of virulence factors. Here, we describe the phylogenetics and ESX-1 comparisons of MFG from invasive infections in two unrelated immunocompetent patients. UMCG_patient1 was isolated from blood from a patient with septic catheter-related thrombophlebitis and UMCG_patient2 from a patient with infected implanted artificial material. First, Miseq (Illumina) was used to perform short-read sequencing. BLAST comparison of the 16s rRNA gene showed 100% identity to both M. conceptionense and M. senegalense. Next, whole genome-based phylogeny was performed using TypeStrain. This showed that both isolates cluster together as a separate branch within the M. conceptionense / M. senegalense clade. Genome BLAST Distance Phylogeny analysis showed that UMCG_patient1 and UMCG_patient2 were related to M. conceptionense CCUG 50187 with a dDDH of 81.7% and 78.4%, respectively, and to M. senegalense DSM 43656 with a dDDH of 87.9% and 83.2%. This indicates that a definite classification was not possible. Finally, ESX-complexes were identified using RAST. The nucleotide content of ESX-1 of UMCG_patient1 was 99.98% identical to UMCG_patient2, whereas identities to closest related type strains were 98.38% (75% cover) to M. conceptionense and 98.15% to M. senegalense. Altogether, this study shows two isolates from acute infections, representing a new human pathotype. The isolates had identical ESX-1 complexes, which were variable between species. ESX-1 composition may act as driver of speciation, and could be useful to define pathotypes in MFG.