Assessment of the in vitro efficacy of the novel antimicrobial peptide CECT7121 against human Gram-positive bacteria from serious infections refractory to treatment.
BACKGROUND
Resistant Gram-positive bacteria are causing increasing concern in clinical practice. This work investigated the efficacy of AP-CECT7121 (an antimicrobial peptide isolated from an environmental strain of Enterococcus faecalis CECT7121) against various pathogenic Gram-positive bacteria.


METHODS
Strains were isolated from intensive care unit patients unresponsive to standard antibiotic treatments. Inhibitory activity of AP-CECT7121 was assessed using the agar-well diffusion method. The most resistant isolates from each species screened (Enterococcus faecium, Enterococcus faecalis,Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Clostridium perfringens and Clostridium difficile) were further examined in time-killing curve studies.


RESULTS
These bactericidal kinetic experiments demonstrated a rapid killing effect with no viable bacteria being detected within 30 and 90 min for enterococcal and streptococcal strains and 180 min for community-acquired methicillin-resistant S. aureus and C. perfringens: viable counts for C. difficile were threefold decreased after 90 min.


CONCLUSIONS
AP-CECT7121 may provide a novel strategy for treating potentially fatal clinical infections in hospitalized patients.
Sparo
M D
MD
Parasitology Division, Moredun Research Institute, Penicuik, UK.
Jones
D G
DG
Sánchez Bruni
S F
SF
D000890:Anti-Infective Agents / Q000494:pharmacology*; D001430:Bacteriocins / Q000494:pharmacology*; D003013:Clostridium / Q000187:drug effects; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000166:cytology / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
D000890:Anti-Infective Agents; D001430:Bacteriocins; D010455:Peptides