title: Activity of the antimicrobial peptide and thanatin analog S-thanatin on clinical isolates of Klebsiella pneumoniae resistant to conventional antibiotics with different structures.
abstract: The treatment of infections caused by bacteria resistant to the vast majority of antibiotics is a challenge worldwide. To evaluate the effect of S-thanatin (an analog of thanatin, a cationic antimicrobial peptide isolated from the hemipteran insect Podisus maculiventris) against microbial resistant to antibiotics, we studied its bactericidal kinetics, synergistic effect, resistance, and activity on clinical isolates of Klebsiella pneumoniae resistant to conventional antibiotics with different structures. The bactericidal rate of S-thanatin was more than 99% against K. pneumoniae ATCC 700603 when bacterial cultures were monitored for 60 min. The peptide was synergistic with beta-lactam cefepime in most of the clinical MDR isolates tested (7/8). An average value of FIC was 0.3708. No synergy was found between the peptide and amoxicillin, gentamycin, tetracycline, or ciprofloxacin in all bacteria tested. A total of 48 isolates of K. pneumoniae with different resistance spectrum tested was susceptible to S-thanatin. The MICs were 6.25-25 mug/ml. No significant difference in the MICs of S-thanatin between the sensitive isolates and the resistant isolates to single antibiotic was observed (P > 0.05). The resistance of K. pneumoniae ATCC 700603 to S-thanatin was slightly higher, when cultured at sub-inhibitory concentration for 5 days. S-thanatin may be an attractive candidate for developing into an antimicrobial agent.
authors.affiliation: Center of Clinical Laboratory Medicine of Zhongda Hospital, Southeast University, Nanjing, 210009, People's Republic of China. nationball@163.com
authors.forename: Guo-Qiu
authors.initials: GQ
authors.lastname: Wu
authors.forename: Jia-Xuan
authors.initials: JX
authors.lastname: Ding
authors.forename: Lin-Xian
authors.initials: LX
authors.lastname: Li
authors.forename: Hai-Liang
authors.initials: HL
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.forename: Zi-Long
authors.initials: ZL
authors.lastname: Shen
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D020062:Heteroptera / Q000737:chemistry; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D010456:Peptides, Cyclic / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D010456:Peptides, Cyclic; C098076:thanatin