In Vitro Activity of the Novel Tetracyclines, Tigecycline, Eravacycline, and Omadacycline, Against Moraxella catarrhalis

• DOI: 10.3343/alm.2021.41.3.293
• Publication Date: 2020-12-11T02:41:49Z
• Authors: Xiang Sun; Bo Zhang; Guangjian Xu; Junwen Chen; Yongpeng Shang; Zhiwei Lin; Zhijian Yu; Jinxin Zheng; Bing Bai
• Keywords: Tigecycline; Broth microdilution

Tigecycline, eravacycline, and omadacycline are recently developed tetracyclines. Susceptibility of microbes to these tetracyclines their molecular mechanisms have not been well elucidated. We investigated the susceptibility Moraxella catarrhalis tigecycline, its resistance against tetracyclines.A total 207 non-duplicate M. isolates were collected from different inpatients. The minimum inhibitory concentrations (MICs) determined by broth microdilution. Tigecycline-, eravacycline-, or omadacycline-resistant induced under in vitro pressure. tet genes mutations 16S rRNA was detected PCR sequencing.Eravacycline had a lower MIC50 (0.06 mg/L) than tigecycline (0.125 isolates. found that 136 (65.7%) tetB gene, 15 (7.2%) positive for tetL; however, presence correlated with high (≥1 MICs. Compared initial MIC after 160 days induction, MICs eravacycline three increased ≥eight-fold, while those two 64-fold. Mutations (C1036T and/or G460A) observed omadacycline-induced resistant isolates, RR (the encoding 16SrRNA (four copies, RR1-RR4) copy number associated omadacycline.Tigecycline, exhibited robust antimicrobial effects catarrhalis. contributed