|
Abstract
(student
research)
The inhibitory effects of garlic, nettle, rosemary and mint on Dermatophilus
congolensis and Malassezia pachydermatis growth in vitro.
(B Gosling, F. Ruedisueli)
Dermatophilus congolensis and Malassezia pachydermatis
can cause cutaneous irritation to predisposed equine and canine
species, respectively. Currently, treatment for both relies heavily
on topical application in the form of chemical washes and lotions.
This study was designed to investigate the inhibitory effect of
garlic, mint, nettle and rosemary towards the of growth of these
transient and commensal micro-organisms.
Experiments were conducted at varying concentrations, with blank
discs and sterile water as controls, in order to determine the extent
of inhibition by each herb.
Using Blood agar and Sabouraud's dextrose agar, Dermatophilus
congolensis and Malassezia pachydermatis were spread
plated onto the respective medium. Blank discs were inoculated with
the concentrations of the herbs and added to the plates. After incubation
periods of 24 and 48 hours, measurements were taken of any inhibition
rings present.
Excess sterile water was found to disrupt the growth of both micro-organisms
in vitro.
Garlic displayed significant disruption of the growth of D. congolensis
(p<0.05), but had little effect on the growth of M. pachydermatis.
Mint was only used on M. pachydermatis and did not produce
any antifungal effects.
Nettle displayed significant inhibitory effects on the growth of
D. congolensis (p<0.05) and showed larger disruption of
the growth of M. pachydermatis than the controls, although
not significant.
For both micro-organisms, rosemary, although not statistically significant,
caused a disruption of growth larger than that displayed by the
controls.
Along side the main study, a pilot study was undertaken to compare
the growth of D. congolensis and a resident equine bacterium, Staphylococcus
xylosus.
In the presence of the resident cutaneous bacteria, D. congolensis
showed a significantly larger growth (p <0.01) than that displayed
by the S. xylosus when in the presence of the potential pathogen.
The findings suggest that D. congolensis may be a successful
competitor against one of the resident cutaneous bacteria of the
equine species. More work would need to be conducted in order to
establish whether D. congolensis shows predominant growth
over other resident bacteria and the relevance of this to the occurrence
of infection.
|
