P45
Clinical, Microbiologic and genomic characterization of a Mycobacteroides abscessus persistent infection – a case report
A Santos(1) M Pinto(2) J Fernandes(3) R Macedo(1)
1:National Reference Laboratory for Tuberculosis, Portuguese National Institute of Health; 2:Bionformatics Unit, Portuguese National Institute of Health; 3:Pneumologist, Portimão Hospital, Algarve University Hospital Centre
Infections with Mycobacteroides abscessus (MAB), a fast-growing Nontuberculous Mycobacteria (NTM), are particularly difficult to eradicate, despite extensive chemotherapy with prolonged regimens. MAB often causes severe respiratory, skin, and mucosal infections in humans and is considered one of the most resistant mycobacteria, as the majority of the strains harbour important virulence factors allowing immune system evasion, adaptation to low oxygen and nutrient starvation, in addition to various intrinsic and acquired mechanisms of antibiotic resistance.
With this work, we aim to present clinical, microbiologic and genomic features of a M. abscessus spp boletti clone isolated from a patient within seven years of disease evolution.
A male patient, 65 y.o., with bilateral bronchiectasis, no other relevant comorbidities, was admitted to the hospital with respiratory symptoms in the beginning 2014. From April 2014 to September 2021, we received eight strains isolated from this patient. Species identification and molecular resistance profile were determined using GenoType Mycobacterium CM® and GenoType NTM-DR® (Hain Lifescience). Five strains were subjected to whole-genome sequencing to evaluate the genetic evolution and adaptation of this strain within its host.
All strains were identified as Mycobacteroides abscessus spp. boletti, resistant to macrolides (erm [41] T28) and belonging to a novel MLST ST. The genomic analysis revealed a discreet (up to 10 SNPs) accumulation of mutations from 2014 to 2021, indicating that the prolonged infection was caused by a single evolving strain. Of note, most of these SNPs targeted genes involved in drug resistance and adaptation to oxidative stress.