Abstract
M.Tech. (Homoeopathy)
Streptococcus pyogenes (S. pyogenes) and Staphylococcus aureus (S. aureus) are
responsible for various infections in humans, including pharyngitis, tonsillitis, cellulitis,
and many others. These bacterial infections have been successfully treated with
antibiotics in the past years; however many bacterial strains have become resistant to
antibiotic treatment, resulting in increased mortality rates. Complementary medicine
may be alternative treatment for bacterial resistant infections. Colloidal silver, an
alternative treatment was studied against S. pyogenes and S. aureus in vitro.
The aim of this study was to investigate the antibacterial effect of 18 and 20 ppm
colloidal silver on Streptococcus pyogenes and Staphylococcus aureus using the
microdilution minimum inhibitory concentration method. The hypothesis was that
colloidal silver would exhibit in vitro antibacterial activity on S. aureus and S. pyogenes..
The method of choice for this study was the microdilution method. The disc diffusion
method was used for trial run and spectrophotometric method was used for confirmatory
and statistical purposes. All experimental procedures were completed in triplicate to
eliminate laboratory errors. The experiments were conducted on S. aureus and
S.pyogenes single colony units obtained from Davies Diagnostics. Pure cultures were
then subcultured aseptically every 24 hours for the duration of the experiment. Mueller-
Hinton agar was used as media. Four paper discs were used and each disc was
impregnated with 18 ppm, 20 ppm colloidal silver, control groups (cefepime and distilled
water) respectively. These discs were placed on agar plates, which had been inoculated
with S. aureus and S. pyogenes respectively. Following 24 hours of incubation, the
Iodonitrotetrazolium chloride (INT) dye was added to the plates and zones of inhibition
were observed, measured and recorded within minutes. The 96 well microdilution
method was used to determine the minimum inhibitory concentration of the 18 and 20
ppm colloidal silver. Results were visually inspected after adding the INT dye following
24 hours of incubation...