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Materials & Methods
Sample Collection
All samples
in this study were collected
between June 15 and June
30, 2006. Infilled synthetic
turf systems were located
at facilities in Pennsylvania
and were in use by all levels
of play ranging from elementary
to professional athletes.
Infill material samples
were collected from both
a 'high use' and a 'low
use' area of each field.
A 'high use' area typically
was a goal mouth or, for
a football only field, an
area between the 30- and
40-yard lines between the
hash marks. A 'low use'
area was typically an area
toward the edge of the field
(but within the field of
play) or an end zone. Approximately
2-3 ml of infill material
were removed from each area
of the field using a sterile
test tube inserted directly
into the infill. Pile fiber
samples were also collected
from many fields by clipping
several fibers from the
backing and transferring
the fibers to a sterile
test tube. Samples were
stored in a cooler and processed
as soon after collection
as possible.
Sample Processing
Approximately
0.075 g of infill material
was transferred to a test
tube containing 10 ml sterile
0.1% peptone broth. The
sample was agitated for
30 seconds Serial dilutions
of each sample were plated
up to 10-3 on both R2A agar
for total organism populations
and Baird-Parker agar, a
selective media for Staphylococcus
(Bennet and Lancette, 1998).
Duplicate platings were
made for each media and
each dilution. Petri plates
were parafilmed and incubated
at room temperature and
colony counts were made
72 hours after processing.
Samples on Baird-Parker
agar were also observed
again after 5 days. Calculations
were then made to determine
the number of colony forming
units (CFU) per gram of
infill material.
For comparison
purposes, soil samples were
also collected from a native
soil and a sand based natural
turfgrass athletic field.
Samples were processed in
the same manner as the infill
material samples with 0.2
grams of soil being used
for processing.
Sampling of Other Surfaces
Samples
were collected from common
surfaces in public areas
as well as from various
surfaces in an athletic
training area. Samples were
collected by swabbing surfaces
with sterile cotton swabs.
Random individuals were
also tested by swabbing
hands and/ or face. Both
R2A and Baird-Parker agar
plates were wiped with the
sterile swabs. Plates were
incubated at room temperature
and colony counts were conducted
after 72 hours for R2A agar
and again at 5 days for
Baird-Parker media.
Identification of Staphylococcus
Aureus Colonies
Gram stains
and latex agglutination
tests (Essers and Radebold,
1980) were performed on
colonies suspected of being
S. aureus. Several potential
S. aureus colonies isolated
from hand and facial swabs
were also included in the
testing.
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