The Synergetic Effect Of Imipenem-Clarithromycin Combination In Themycobacteroides Abscessuscomplex

Background Nontuberculous mycobacteria (NTM) are ubiquitous organisms and the incidence of NTM infections has been increasing in recent years.Mycobacteroides abscessus(M. abscessus) is one of the most antimicrobial-resistant NTM; however, no reliable antibiotic regimen can be officially advocated. We evaluated the efficacy of clarithromycin in combination with various antimicrobial agents against theM. abscessuscomplex. Results Twenty-nine clinical strains ofM. abscessuswere isolated from various clinical samples. Of the isolates, 10 (34.5%) were ofM. abscessussubsp.abscessus, 18 (62.1%) ofM. abscessussubsp.massiliense, and 1 (3.4%) ofM. abscessussubsp.bolletii. MICs of three antimicrobial agents (amikacin, imipenem, and moxifloxacin) were measured with or without clarithromycin. The imipenem-clarithromycin combination significantly reduced MICs compared to clarithromycin and imipenem monotherapies, including against resistant strains. The association between susceptibility of theM. abscessuscomplex and each combination of agents was significant (p = 0.001). Adjusted residuals indicated that the imipenem-clarithromycin combination had the synergistic effect (adjusted residual = 3.1) and suppressed the antagonistic effect (adjusted residual = - 3.1). In subspecies ofM. abscessuscomplex, the association with susceptibility ofM. abscessussubsp.massiliensewas similarly statistically significant (p = 0.036: adjusted residuals of synergistic and antagonistic effect respectively: 2.6 and - 2.6). The association with susceptibility ofM. abscessussubsp.abscessusalso showed a similar trend but did not reach statistical significance. Conclusion Our data suggest that the imipenem-clarithromycin combination could be the recommended therapeutic choice for the treatment ofM. abscessuscomplex owing to its ability to restore antimicrobial susceptibility.