throat, care should be taken to sample an area 
of inflammation or exudate. If only one speci- 
men can be taken, it should be from the throat. 
In carrier surveys, nasopharyngeal specimens 
are preferable. Unless a suitable transport 
method is used, swabs should be planted within 
not more than four hours after the specimen is 
taken. All other specimens should be refrigerated 
from the time taken until they are cultured, 
a. Specimens for isolation of the agent 
Initial isolation of streptococci should, if 
possible, be carried out in a competent 
laboratory close to the source of the 
specimen. 
(1) Anterior Nasal, Nasopharyngeal, and 
Throat Specimens: 
Material taken from the upper respira- 
tory passages is the most common type 
of specimen cultured for hemolytic 
streptococci. Individual sterile swabs 
are used and anterior nasal specimens 
are obtained by introducing the swab 
into the nares for about an inch. To 
obtain a nasopharyngeal specimen, the 
tip of the nose should be elevated, and 
the swab, moistened with broth or 
saline, should be introduced along the 
floor of the nasal cavity, under the 
middle turbinate, to the pharyngeal 
wall. Be sure to touch any exudate 
present. With the tongue depressed, 
pass a dry swab over the tonsils and 
pharynx, being sure not to touch the 
tongue. If inoculation of an isolation 
medium must be delayed beyond four 
hours, use one of the following trans- 
port methods ; 
(a) The swab may be inserted into a 
sterile screw-cap tube containing 
indicator silica gel. 
(b) A blood agar slant in a screw-cap 
tube may be streaked with the 
swab which is then left in place 
during transport. 
(c) Several filter paper transport kits 
are available from commercial 
sources. The swab should be rolled 
and scrubbed onto the piece of 
filter paper and discarded. The 
filter paper should be allowed to 
air dry for 3 to 4 minutes; it 
should then be refolded into its 
carrier paper, and returned to the 
envelope. 
(2) Pus, Sputum, Spinal Fluid, Discharges, 
Exudates, Urine: 
A Gram stain of the specimen at the 
local or hospital laboratory will in- 
dicate roughly the number of organisms 
present, and if there are only a few, the 
fluid may be centrifuged and the sedi- 
ment cultured. Streak the blood agar 
plates so as to obtain well-isolated 
colonies and inoculate a tube of en- 
riched infusion broth. 
(3) Blood 
After decontaminating the skin with 
4% iodine followed by wiping with 
70% alcohol, use a sterile syringe to 
draw about 10 ml. of blood and add it 
to a flask containing 2 ml. of 3% 
sterile sodium citrate or 1.0 mg. of 
heparin. After mixing, transfer the 
specimen aseptically to 100 ml. of 
blood culture broth. A Loeffler slant or 
a blood agar plate may also be inocu- 
lated. If a plate is used, limit the 
inoculum to a small area of the medium 
and take the plate to the laboratory 
where streaking for isolation can be 
done properly with a wire loop. Do not 
mail Petri dishes. The addition of an- 
tagonists to media for blood cultures 
from patients undergoing chemotherapy 
and the addition of penicillinase in 
cultures from patients receiving peni- 
cillin are usually unnecessary. 
(4) Milk 
Refrigerate the specimen for as much 
of the time as possible before it is 
cultured. If refrigeration is impossible, 
mix the specimen with Vs volume of 
glycerol. Culture suitable dilutions in 
blood agar pour plates in duplicate, 
mixing the sample and melted medium 
in the plate so as to get isolated 
colonies. Incubate one plate aerobically 
and one under anaerobic conditions, 
b. Streptococcus grouping by fluorescent anti- 
body (FA) technic 
Smears made directly from the patient are 
unsatisfactory for examination by FA tech- 
nic. For this examination, specimens may be 
transported in the same manner as for cul- 
ture. The swab should be placed in Todd- 
Hewitt broth for enrichment purposes for 
two to three hours at 37 °C, before the FA 
smears are made. 
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