Cationic peptide of the male reproductive tract, HE2alpha, displays antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis.
OBJECTIVE
To analyse the in vitro antimicrobial effects of synthetic HE2alpha peptide against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis.


METHODS
The HE2alpha peptide was synthesized based on the C-terminal sequence of the HE2alpha protein. The bacterial strains tested included two antibiotic-susceptible strains of N. gonorrhoeae and four antibiotic-resistant clinical isolates, as well as S. aureus ATCC 29213 and E. faecalis ATCC 29212. Susceptibility determinations were carried out either in 0.7% casamino acids for N. gonorrhoeae isolates or in 10 mM phosphate buffer for S. aureus and E. faecalis strains. Antibacterial effects were measured in a dose- and time-dependent manner. After exposure to the peptide in solution, the number of viable cells was determined by counting colony forming units (cfu).


RESULTS
The HE2alpha peptide exhibited time- and dose-dependent antibacterial effects on all N. gonorrhoeae isolates tested. S. aureus and E. faecalis strains were also susceptible to the peptide. All strains tested were susceptible to the peptide at high concentrations (50 or 100 mg/L) and some strains were susceptible to a peptide concentration of 25 mg/L.


CONCLUSIONS
The peptide HE2alpha, which is derived from the male urogenital tract, exhibits antibacterial activity against both gram-positive and gram-negative pathogens in vitro. The peptide is active against both antibiotic-susceptible and -resistant N. gonorrhoeae isolates. Further investigation of the antimicrobial properties of the peptide is warranted.
Liao
M
M
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, ON, Canada, K1H 8M5.
Ruddock
P S
PS
Rizvi
A S
AS
Hall
S H
SH
French
F S
FS
Dillon
J R
JR
D000954:Antigens, Surface / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D013293:Enterococcus faecalis / Q000187:drug effects*; D006020:Glycopeptides / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000187:drug effects*; D011994:Recombinant Proteins / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013997:Time Factors
D000954:Antigens, Surface; D023181:Antimicrobial Cationic Peptides; D006020:Glycopeptides; D011994:Recombinant Proteins; C087044:SPAG11A protein, human