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A. SARAGEA ET AL.
treatment and prophylaxis. If it is not possible a t a given time to carry out
an extensive microbiological investigation, it is advisable to delay 1 or 2
days in order to organise a complete and simultaneous check up.
I n non-epidemic situations the procedures used for mapping the
distribution of healthy carriers are similar, the examination of both nasal
and pharyngeal exudates being obligatory.
3. Isolation of the organism in patient and carriers
(a) In patient. For reasons of urgency in suspected cases of faucial diphtheria, the following procedures are recommended :
O n theJirst day
(i) The first swab is used for a direct smear.
(ii) The second swab is plated on Tinsdale and blood agar (BA) media;
the swab may also be plated on CTRA. The blood agar medium is
used in detecting other pathogenic species too (i.e. P-haemolytic
streptococci, haemolytic staphylococci, etc.).
(iii) The third swab is immersed in the ECST enrichment medium
(2-3 ml in tubes of 12/120 mm). All media are incubated overnight
at 37°C; for the ECST medium, 10-12 h of incubation are sufficient.
(iv) The nasal swab is enriched in ECST medium and follows the
same procedure as for swab No. 3.
O n the second day
Plates are examined and specific colonies are diagnosed according to their
characteristics : black coloured brown haloed on Tinsdale or buttery white
greyish granular colonies on BA.
From suspected colonies on Tinsdale plates, a Gram-stained smear is
effected to confirm the presence of corynebacteria bacilli, thereafter two or
three colonies are picked up on a Loeffler slant and the culture is incubated
overnight at 37°C. This culture will represent the stock culture for further
identification.
I n view of the urgency of diagnosis some isolated colonies may be picked
and sugar fermentation (glucose, sucrose, glycogen), urea, toxigenicity test
(Elek) as well as slide agglutination can be carried out.
If there is no growth on the plates, the enriched swab from the ECST
medium is plated on Tinsdale. Isolation and identification of the developed
culture follow the same steps as for the previous swab.
O n the third day
The identification and typing of the stock culture from the Loeffler slant
is effected by:
A. SARAGEA ET AL.
treatment and prophylaxis. If it is not possible a t a given time to carry out
an extensive microbiological investigation, it is advisable to delay 1 or 2
days in order to organise a complete and simultaneous check up.
I n non-epidemic situations the procedures used for mapping the
distribution of healthy carriers are similar, the examination of both nasal
and pharyngeal exudates being obligatory.
3. Isolation of the organism in patient and carriers
(a) In patient. For reasons of urgency in suspected cases of faucial diphtheria, the following procedures are recommended :
O n theJirst day
(i) The first swab is used for a direct smear.
(ii) The second swab is plated on Tinsdale and blood agar (BA) media;
the swab may also be plated on CTRA. The blood agar medium is
used in detecting other pathogenic species too (i.e. P-haemolytic
streptococci, haemolytic staphylococci, etc.).
(iii) The third swab is immersed in the ECST enrichment medium
(2-3 ml in tubes of 12/120 mm). All media are incubated overnight
at 37°C; for the ECST medium, 10-12 h of incubation are sufficient.
(iv) The nasal swab is enriched in ECST medium and follows the
same procedure as for swab No. 3.
O n the second day
Plates are examined and specific colonies are diagnosed according to their
characteristics : black coloured brown haloed on Tinsdale or buttery white
greyish granular colonies on BA.
From suspected colonies on Tinsdale plates, a Gram-stained smear is
effected to confirm the presence of corynebacteria bacilli, thereafter two or
three colonies are picked up on a Loeffler slant and the culture is incubated
overnight at 37°C. This culture will represent the stock culture for further
identification.
I n view of the urgency of diagnosis some isolated colonies may be picked
and sugar fermentation (glucose, sucrose, glycogen), urea, toxigenicity test
(Elek) as well as slide agglutination can be carried out.
If there is no growth on the plates, the enriched swab from the ECST
medium is plated on Tinsdale. Isolation and identification of the developed
culture follow the same steps as for the previous swab.
O n the third day
The identification and typing of the stock culture from the Loeffler slant
is effected by: