Jun 23, 2006

Alanine esters of enterococcal lipoteichoic acid play a role in biofilm formation and resistance to antimicrobial peptides

Infection and Immunity
Francesca FabrettiJohannes Huebner

Abstract

Enterococcus faecalis is among the predominant causes of nosocomial infections. Surface molecules like d-alanine lipoteichoic acid (LTA) perform several functions in gram-positive bacteria, such as maintenance of cationic homeostasis and modulation of autolytic activities. The aim of the present study was to evaluate the effect of d-alanine esters of teichoic acids on biofilm production and adhesion, autolysis, antimicrobial peptide sensitivity, and opsonic killing. A deletion mutant of the dltA gene was created in a clinical E. faecalis isolate. The absence of d-alanine in the LTA of the dltA deletion mutant was confirmed by nuclear magnetic resonance spectroscopy. The wild-type strain and the deletion mutant did not show any significant differences in growth curve, morphology, or autolysis. However, the mutant produced significantly less biofilm when grown in the presence of 1% glucose (51.1% compared to that of the wild type); adhesion to eukaryotic cells was diminished. The mutant absorbed 71.1% of the opsonic antibodies, while absorption with the wild type resulted in a 93.2% reduction in killing. Sensitivity to several cationic antimicrobial peptides (polymyxin B, colistin, and nisin) was considerably increased in the mut...Continue Reading

  • References46
  • Citations119

Citations

Mentioned in this Paper

Gram-Positive Bacteria
Pathogenic Aspects
Pathogenesis
Colistin
Science of Morphology
Gene Deletion Abnormality
Autolysis
Abufne
Nisin A
Nisin

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