P47
In vitro omadacycline against Mycobacteroides abscessus complex
T Blanco-Martín(1,2) C Riazzo(1,2) P Ruiz(4) L Martínez-Martínez(1,2,3,4) M Causse(1,2)
1:Reina Sofía University Hospital, Córdoba, Spain; 2:Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; 3:Spanish Network for research in infectious diseases (REIPI), Institute of Health Carlos III, Madrid, Spain; 4:Depatment of Agricultural Chemistry, Soil Science and, Microbiology, University of Córdoba, Spain.
Oral treatment options against infections caused by Mycobacteroides abscessus complex are limited. Treatment includes the association of multiples antimicrobials (many of them only available as intravenous formulation) due to the high prevalence of antibiotic resistance and the occurrence of adverse reactions. In comparison to other tetracyclines, omadacycline has shown an effective inhibition of protein synthesis, activity against isolates with tetracycline efflux pumps and even, ribosomal protection mechanisms.
28 strains of M. abscessus were included. Subespecies of M. abscessus were identified using GenoType NTM-DR (Bruker). Antimicrobial susceptibility testing of doxycycline and minocycline was performed using Sensititre™ RAPMYCO2 panels. Omadacycline MIC was determined by broth microdilution (0.0015-8 mg/L). MICs were read after 5 days of incubation. Results were interpreted according to CLSI guidelines. Staphylococcus aureus ATCC 29213 was used as control strain.
Among the 28 isolates tested (19 M. abscessus abscessus, 8 M. abscessus massiliense and 1 M. bolletii), clinical categories of doxycycline and minocycline corresponded to resistance in 25 and 22 isolates, intermediate in 1 and 5 isolates, and susceptible in 2 and 1 isolates, respectively.
Omadacycline MIC ranged from 0.0015 to 0.5 mg/L for all the species tested. MIC₅₀ and MIC₉₀ were generally similar for all the subespecies corresponding to 0.125 and 0.5 for M. abscessus abscessus, 0.03 and 0.125 for M. abscessus massiliense and 0.5 and 0.5 for M. abscessus bolletii.
In vitro activity of omadacycline against M. abscessus complex suggests that this agent might represent an alternative oral therapeutic option for treatment of infections caused by these organisms.