Abstract
Purpose: Because of
the emergence of multi-antibiotic resistant bacteria, a
number of infectious diseases have become a major concern to treat in health
care services worldwide. This situation is worsened by the fact that very
limited progress has been made in developing new and potent antibiotics in
recent years. In this context antimicrobial peptides (AMPs) represent new
potential therapeutic compounds with bactericidal or bacteriostatic activity
against closely related bacterial strains.
Methods: In
this study, a collection of enterococci (n=170) from clinical sources were
investigated for their potential to inhibit multiresistant nosocomial
enterococci from Iranian hospitals.
Results: Four isolates produced antimicrobial peptides that
inhibited all the antibiotic resistant enterococci. This included three Enterococcus faecium
isolates producing combinations of enterocin A, B and L50 AB. The most potent
antagonism was produced by E. faecalis HO91. Purification and subsequent characterization by MALDI-TOF MS, Edman
degradation and DNA-sequencing revealed that the antimicrobial compound was
Hiracin. The purified Hiracin was evaluated for antibacterial activity
against 12 multiresistant enterococcal isolates from clinical samples. The
results demonstrated that Hiracin is highly
effective towards enterococci which were resistant even to antibiotics from
four distinct classes.
Conclusion: The present research addresses Hiracin as a promising
alternative to conventional antibiotics in treatment of multiresistant enterococcal
infections.