{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T11:10:38Z","timestamp":1788347438459,"version":"build-2803163510"},"reference-count":0,"publisher":"American Society for Microbiology","issue":"8","license":[{"start":{"date-parts":[[1996,8,1]],"date-time":"1996-08-01T00:00:00Z","timestamp":838857600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Antimicrob Agents Chemother"],"published-print":{"date-parts":[[1996,8]]},"abstract":"<jats:p>A synthetic peptide, KFFKFFKFFK [corrected], consisting of cationic lysine residues and hydrophobic phenylalanine residues was found to sensitize gram-negative bacteria to hydrophobic and amphipathic antibiotics. At a concentration of 3 micrograms\/ml, it decreased the MIC of rifampin for smooth, encapsulated Escherichia coli by a factor of 300. Other susceptible bacterial species included Enterobacter cloacae, Klebsiella pneumoniae, and Salmonella typhimurium, but Pseudomonas aeruginosa was resistant. Similar results were obtained with another synthetic peptide, IKFLKFLKFLK [corrected]. The fractional inhibitory concentration indices for the synergism of these peptides with rifampin, erythromycin, fusidic acid, and novobiocin were very close to those determined for the previously characterized potent outer-membrane-disorganizing agents polymyxin B nonapeptide and deacylpolymyxin B. KFFKFFKFFK [corrected] had direct activity against the gram-positive organism Micrococcus strain ML36, was strongly hemolytic, and was as active on polymyxin-resistant E. coli mutants as on their parent. These three attributes made KFFKFFKFFK [corrected] different from polymyxin derivatives and similar to cationic detergents, such as cetylpyridinium chloride. However, whereas the MIC of cetylpyridinium chloride for E. coli is low (0.5 to 4 micrograms\/ml), that of KFFKFFKFFK [corrected] is much higher (30 to 100 micrograms\/ml). Other groups of synthetic peptides studied included polymyxin-like peptides with an intrachain disulfide bridge. Their synergism with antibiotics was less marked. Still other peptides, including KEKEKEKEKE and KKKKKKFLFL, lacked any synergism with the probe antibiotics.<\/jats:p>","DOI":"10.1128\/aac.40.8.1801","type":"journal-article","created":{"date-parts":[[2018,10,9]],"date-time":"2018-10-09T00:26:39Z","timestamp":1539044799000},"page":"1801-1805","update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":172,"title":["Group of peptides that act synergistically with hydrophobic antibiotics against gram-negative enteric bacteria"],"prefix":"10.1128","volume":"40","author":[{"given":"M","family":"Vaara","sequence":"first","affiliation":[{"name":"Department of Bacteriology and Immunology, University of Helsinki, Finland. Martti.Vaara@Helsinki.Fi"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M","family":"Porro","sequence":"additional","affiliation":[{"name":"Department of Bacteriology and Immunology, University of Helsinki, Finland. Martti.Vaara@Helsinki.Fi"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","container-title":["Antimicrobial Agents and Chemotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.40.8.1801","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/AAC.40.8.1801","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T20:09:02Z","timestamp":1645474142000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/AAC.40.8.1801"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,8]]},"references-count":0,"journal-issue":{"issue":"8","published-print":{"date-parts":[[1996,8]]}},"alternative-id":["10.1128\/AAC.40.8.1801"],"URL":"https:\/\/doi.org\/10.1128\/aac.40.8.1801","relation":{},"ISSN":["0066-4804","1098-6596"],"issn-type":[{"value":"0066-4804","type":"print"},{"value":"1098-6596","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,8]]},"assertion":[{"value":"1996-08-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}