In vitro activity of an aqueous allicin extract and a novel allicin topical gel formulation against Lancefield group B streptococci.
BACKGROUND
Studies have shown the efficacy of intra-partum antibiotics in preventing early-onset group B streptococcal sepsis. This approach results in a high intra-partum antibiotic use. Worryingly, the same antibiotics used in prophylaxis are also first-line treatment for neonatal sepsis, and antibiotic exposure in the peri-natal period has been shown to be a risk factor for late-onset serious bacterial infections and allergic disease. Antibiotic exposure in the peri-natal period is becoming a major public health issue; alternative strategies are needed. Garlic has been traditionally used to treat vaginal infections. Allicin is the main antibacterial agent isolated from garlic.


OBJECTIVE
The aim of the study was to investigate the in vitro activity of a novel allicin extract in aqueous and gel formulation against 76 clinical isolates of Lancefield group B streptococci (GBS).


METHODS
MICs and MBCs of allicin were determined for 76 GBS isolates by agar dilution and microtitre plate methods. Killing kinetics were determined for a selected 16 of the 76 strains. Agar diffusion tests were compared for allicin liquid and gel (500 mg/L).


CONCLUSIONS
MICs and MBCs of allicin liquid were 35 to 95 mg/L and 75 to 315 mg/L, respectively. Time/dose kill curves produced a 2-3 log reduction in cfu/mL within 3 h and no detectable growth at 8 and 24 h. A novel 500 mg/L allicin gel produced an average zone size of 23+/-6 mm compared with 21+/-6 mm for allicin in water. Aqueous allicin is bactericidal against GBS isolates and maintains activity in a novel gel formulation.
Cutler
Ronald R
RR
University of East London, Romford Rd, Stratford, London E15 4LZ, UK. rcutler@uel.ac.uk
Odent
Michel
M
Hajj-Ahmad
Hussein
H
Maharjan
Sunil
S
Bennett
Norman J
NJ
Josling
Peter D
PD
Ball
Vanessa
V
Hatton
Paulette
P
Dall'Antonia
Martino
M
D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004220:Disulfides; D005260:Female; D005737:Garlic / Q000737:chemistry; D006801:Humans; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D013290:Streptococcal Infections / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000187:drug effects* / Q000302:isolation & purification; D013441:Sulfinic Acids / Q000302:isolation & purification / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004220:Disulfides; D013441:Sulfinic Acids; C006452:allicin