Bacteriostatic activity of human lactoferrin against Staphylococcus aureusis a function of its iron-binding properties and is not influenced by antibiotic resistance

The in vitro antistaphylococcal activity of lactoferrin and the antibiotic resistance of clinical Staphylococcus aureus isolates obtained from three d ifferent sites of infection were examined. Antibiotic, but not lactoferrin resistance correlated with selective antibiotic pressure, and nosocomial an d most community isolates were antibiotic resistant, whereas only a third o f each group was resistant to lactoferrin. The antimicrobial activity of la ctoferrin, both in defined medium and in normal human plasma serum, was dep endent upon its ferrochelating properties. Therapeutic approaches based on the use of ferrochelating agents such as lactoferrin combined with antimicr obial drugs may help to counteract the reduced efficacy of current antibiot ics. (C) 2001 Federation of European Microbiological Societies. Published b y Elsevier Science B.V. All rights reserved.