Effect of antimicrobial peptides on colistin-susceptible and colistin-resistant strains of Klebsiella pneumoniae and Enterobacter asburiae

Béla Kádár, B. Kocsis, Katalin Kristof, A. Tóth, D. Szabó

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In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides.

Original languageEnglish
Pages (from-to)501-508
Number of pages8
JournalActa Microbiologica et Immunologica Hungarica
Issue number4
Publication statusPublished - Dec 1 2015



  • Antibiotic-resistance
  • Antimicrobial peptides
  • Colistin
  • Enterobacteriaceae

ASJC Scopus subject areas

  • Immunology and Microbiology(all)
  • Medicine(all)

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