{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T15:20:40Z","timestamp":1777389640573,"version":"3.51.4"},"reference-count":12,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,5,12]],"date-time":"2022-05-12T00:00:00Z","timestamp":1652313600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:p>To evaluate <jats:italic>in vitro<\/jats:italic> antibacterial activity of MRX-8 against gram-negative bacteria recently isolated from China, 765 clinical isolates were collected randomly from 2017 to 2020, including <jats:italic>Enterobacterales<\/jats:italic> and <jats:italic>P. aeruginosa<\/jats:italic> and <jats:italic>A. baumannii<\/jats:italic>, <jats:italic>S. maltophilia, B. cepacia, Alcaligenes app.<\/jats:italic> and <jats:italic>Haemophilus<\/jats:italic> spp. isolates. All strains were performed with antimicrobial susceptibility testing by broth microdilution method according to the CLSI 2021. Antimicrobial agents included MRX-8, polymyxin B, colistin, amikacin, ceftriaxone, ceftazidime, cefepime, ceftazidime-avibactam, cefoperazone-sulbactam, meropenem, ciprofloxacin, ampicillin, ampicillin-sulbactam and levofloxacin. For carbapenem-susceptible and carbapenem-resistant <jats:italic>E.coli<\/jats:italic> isolates, the MIC<jats:sub>50\/90<\/jats:sub> of MRX-8 was 0.125\/0.25 mg\/L and 0.06\/0.125 mg\/L, respectively. For carbapenem-susceptible and carbapenem-resistant <jats:italic>K. pneumoniae<\/jats:italic> isolates, the MIC<jats:sub>50\/90<\/jats:sub> of MRX-8 was 0.25\/0.5 mg\/L and 0.125\/0.5 mg\/L, respectively. For polymyxins (polymyxin B and colistin)-resistant <jats:italic>E. coli<\/jats:italic> and <jats:italic>K. pneumoniae<\/jats:italic>, MIC<jats:sub>50<\/jats:sub> of MRX-8 was 4-16 mg\/L and MIC<jats:sub>90<\/jats:sub> was &amp;gt;32 mg\/L. The MIC<jats:sub>50<\/jats:sub> and MIC<jats:sub>90<\/jats:sub> of MRX-8 for other <jats:italic>Klebsiella<\/jats:italic> spp. except <jats:italic>K. pneumoniae<\/jats:italic>, <jats:italic>Citrobacter<\/jats:italic> spp., <jats:italic>S. enterica<\/jats:italic> and <jats:italic>Shigella<\/jats:italic> spp. isolates ranged 0.06-0.125 mg\/L and 0.06-0.25mg\/L, respectively. For <jats:italic>Morganella<\/jats:italic> spp.<jats:italic>, Proteus<\/jats:italic> spp.<jats:italic>, Providencia<\/jats:italic> spp.<jats:italic>, Serratia<\/jats:italic> spp., <jats:italic>S. maltophilia<\/jats:italic> and <jats:italic>B. cepacia<\/jats:italic>, all MIC<jats:sub>50<\/jats:sub> of MRX-8 was &amp;gt;32mg\/L. For carbapenem susceptible and resistant <jats:italic>P. aeruginosa<\/jats:italic>, the MIC<jats:sub>50<\/jats:sub> and MIC<jats:sub>90<\/jats:sub> of MRX-8 was both 1mg\/L, and that for <jats:italic>A. baumannii<\/jats:italic> was 0.5mg\/L and 0.5-1mg\/L. For <jats:italic>Alcaligenes<\/jats:italic> spp. and <jats:italic>Haemophilus<\/jats:italic> spp., MIC<jats:sub>50\/90<\/jats:sub> was 1\/4 mg\/L and 0.25\/0.5 mg\/L. MRX-8 was more effective against most clinically isolated gram-negative isolates, including carbapenem-resistant <jats:italic>E. coli<\/jats:italic>, <jats:italic>K. pneumoniae<\/jats:italic>, <jats:italic>P. aeruginosa<\/jats:italic> and <jats:italic>A. baumannii<\/jats:italic>, highlighting its potential as valuable therapeutics.<\/jats:p>","DOI":"10.3389\/fcimb.2022.829592","type":"journal-article","created":{"date-parts":[[2022,5,12]],"date-time":"2022-05-12T15:29:34Z","timestamp":1652369374000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":18,"title":["In Vitro Activity of MRX-8 and Comparators Against Clinical Isolated Gram-Negative Bacilli in China"],"prefix":"10.3389","volume":"12","author":[{"given":"Shi","family":"Wu","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dandan","family":"Yin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peiyuan","family":"Zhi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yan","family":"Guo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yang","family":"Yang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Demei","family":"Zhu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Fupin","family":"Hu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2022,5,12]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"626","DOI":"10.1097\/QCO.0b013e328358afe5","article-title":"'Old' Antibiotics for Emerging Multidrug-Resistant Bacteria","volume":"25","author":"Bergen","year":"2012","journal-title":"Curr. 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