IV. INVESTIGATION OF C. DIPHTHERIAE
141
(i) Gram-stained smear for microbiological morphology; Methylene
blue, Neisser or del Vecchio staining for metachromatic granules.
'(ii) Cultural characters on solid (CTBA) and liquid (broth) media.
(iii) Enzymic characters : carbohydrate fermentations, urease and
(iv) Slide agglutination.
(v) Toxigenicity by in vitro Elek test or in vivo guinea pig or rabbit
(vi) Phage typing, lysogenicity and bacteriocin typing.
cystinase production.
inoculation.
In conclusion, at least 24-36 h are necessary for a rapid diagnosis in a
suspected infection. In the next 48-72 h, biotype, toxigenicity and phage
type can be defined.
(b) In carrier. Both nose and pharynx, should be swabbed for C. diphtheriae diagnosis.
Microbiological procedures are as follows :
On the$rst day
Swabs are immersed in 2-3 ml ECST medium for at least 10-12 h and
incubated at 37°C.
On the second day
The enriched swabs are plated on Tinsdale medium, nose and throat
each on half of the same plate, and incubated for 24 or 48 h at 37°C.
On the third day
Plates are checked for typical brown-haloed colonies and a GramSpecific colonies are picked on Loeffler slants, for stock cultures and
stained smear is effected for a provisional diagnosis.
incubated overnight at 37°C.
On the fourth day
Smears, enzymes, toxin, sero-agglutination, phage typing, lysogenicity
and bacteriocin type are checked.
In conclusion, in carriers, the identification of C. diphtheriae can be obtained in 48 h and the biotype, toxigenicity and phage type can be done
in 96 h.
4. Identijication of C. diphtheriae
C. diphtheriae species are listed in Tables VI and VII.
The characterisation and diagnosis of corynebacteria and the biotypes of
141
(i) Gram-stained smear for microbiological morphology; Methylene
blue, Neisser or del Vecchio staining for metachromatic granules.
'(ii) Cultural characters on solid (CTBA) and liquid (broth) media.
(iii) Enzymic characters : carbohydrate fermentations, urease and
(iv) Slide agglutination.
(v) Toxigenicity by in vitro Elek test or in vivo guinea pig or rabbit
(vi) Phage typing, lysogenicity and bacteriocin typing.
cystinase production.
inoculation.
In conclusion, at least 24-36 h are necessary for a rapid diagnosis in a
suspected infection. In the next 48-72 h, biotype, toxigenicity and phage
type can be defined.
(b) In carrier. Both nose and pharynx, should be swabbed for C. diphtheriae diagnosis.
Microbiological procedures are as follows :
On the$rst day
Swabs are immersed in 2-3 ml ECST medium for at least 10-12 h and
incubated at 37°C.
On the second day
The enriched swabs are plated on Tinsdale medium, nose and throat
each on half of the same plate, and incubated for 24 or 48 h at 37°C.
On the third day
Plates are checked for typical brown-haloed colonies and a GramSpecific colonies are picked on Loeffler slants, for stock cultures and
stained smear is effected for a provisional diagnosis.
incubated overnight at 37°C.
On the fourth day
Smears, enzymes, toxin, sero-agglutination, phage typing, lysogenicity
and bacteriocin type are checked.
In conclusion, in carriers, the identification of C. diphtheriae can be obtained in 48 h and the biotype, toxigenicity and phage type can be done
in 96 h.
4. Identijication of C. diphtheriae
C. diphtheriae species are listed in Tables VI and VII.
The characterisation and diagnosis of corynebacteria and the biotypes of