Antimicrobial activity of eravacycline and other comparative agents on aerobic and anaerobic bacterial pathogens in Taiwan: A clinical microbiological study.

Objectives: Eravacycline, a new tetracycline derivative, exhibits broad-spectrum antimicrobial susceptibility. This study aimed to comprehensively investigate in vitro activities of eravacycline, tigecycline, and ertapenem against various Gram-positive, Gram-negative, and anaerobic bacteria.
Methods: Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. The following bacterial species were collected: vancomycin-sensitive (VS) Enterococci species, vancomycin-resistant Enterococci species (VRE), Staphylococcus aureus, Streptococcus anginosus, Bacteroides species, Clostridioides difficile, Clostridium innocuum, Clostridium perfringens, Parabacteroides distasonis, and Stenotrophomonas maltophilia.
Results: We found that eravacycline exhibited superior in vitro activity compared to tigecycline and ertapenem. Notably, it exhibited the lowest MIC ₉₀ for several bacterial species, including VS E. faecalis (0.12 µg/mL), VS E. faecium (0.12 µg/mL), and others. Besides, VRE was susceptible to eravacycline (MIC ₉₀ :0.12 µg/mL) and tigecycline (MIC ₉₀ :0.12 µg/mL), but was all resistant to ertapenem (MIC ₉₀ > 64 µg/mL). S. aureus was also susceptible to eravacycline (MIC ₉₀ :0.5 µg/mL) as well as tigecycline (MIC ₉₀ :1.0 µg/mL). Furthermore, S. anginosus showed higher susceptibility to eravacycline (MIC ₉₀ :2.0 µg/mL) and tigecycline (MIC ₉₀ :4.0 µg/mL), but lower to ertapenem (MIC ₉₀ :32.0 µg/mL). Eravacycline and tigecycline also demonstrated good susceptibility to anaerobes, including Bacteroides species (susceptibility rate: 100%), P. distasonis (100%), C. difficile (94.1‒100%), C. innocuum (94.1‒96.1%), and C. perfringens (88.9‒96.3%). For S. maltophilia, both tigecycline and eravacycline showed an MIC ₉₀ of 2 µg/mL. A moderate-to-strong correlation (rho = 0.608-0.804, P < 0.001) was noted between the MIC values of eravacycline and tigecycline against various bacterial species.
Conclusions: Our study highlights the potential of eravacycline as an effective treatment option for multidrug-resistant bacterial infections.
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