Open AccessRole of uropathogenic Escherichia coli OmpT in the resistance against human cathelicidin LL ‐37
Author(s) -
Bran John R.,
Thomassin JennyLee,
Desloges Isabelle,
Gruenheid Samantha,
Moual Hervé
Publication year - 2013
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12185
Subject(s) - escherichia coli , microbiology and biotechnology , cathelicidin , bacterial outer membrane , biology , mutant , antimicrobial peptides , antimicrobial , chemistry , biochemistry , gene
Uropathogenic Escherichia coli ( UPEC ) strains are among the most prevalent causative agents of urinary tract infections. To establish infection, UPEC must overcome the bactericidal action of host antimicrobial peptides. Previously, the enterohaemorrhagic E. coli outer membrane protease, OmpT, was shown to degrade and inactivate the human antimicrobial peptide LL ‐37. This study aims to investigate the involvement of UPEC OmpT in LL ‐37 degradation. An ompT deletion mutant was generated in the prototypical UPEC strain CFT 073. Western blot analysis showed that the OmpT protein level is moderate in CFT 073. In agreement, OmpT was shown to partially cleave LL ‐37. However, no difference in the minimum inhibitory concentration of LL ‐37 was observed between CFT 073 and the ompT mutant. Plasmid complementation of ompT , which led to increased OmpT levels, resulted in complete cleavage of LL ‐37 and a fourfold increase in the minimum inhibitory concentration. The analysis of other UPEC isolates showed similar OmpT activity levels as CFT 073. Although UPEC OmpT can cleave LL ‐37, we conclude that the low level of OmpT limits its contribution to LL ‐37 resistance. Collectively, these data suggest that UPEC OmpT is likely accompanied by other LL ‐37 resistance mechanisms.