diphtheriae tox gene), determine their biotypes (2 variant gravis and 12 variant mitis), and characterize their toxin production using the Elek test
(positive for 9 isolates).
Diphtheria on microscopy, cultures and positive toxin assay on Elek test
are required for definitive diagnosis.
A strain of Corynebacterium ulcerans was subsequently isolated from the culture specimen at CDC, and toxin production by this strain was confirmed by a toxin-antitoxin precipitation assay (Elek test
) and by PCR assay on the isolate.
However, a modified Elek test
yielded a negative result (8).
We determined DT production using a modified Elek test
(6); we used C.
Diphtheria toxin production was evaluated by a modified Elek test
FRC24 is a toxigenic isolate; toxigenicity was confirmed by both tox gene detection and Elek test
Results from use of the modified Elek test
(6) indicated that all feline isolates were negative for production of diphtheria toxin; however, an atypical precipitation was observed after 36 h of incubation.
ulcerans tox-specific PCR (4), and the Elek test
as described previously (4,5).
Toxigenicity was determined by both dtx polymerase chain reaction and Elek test
Easy-to-perform modified Elek test
to identify Shiga-like toxin-producing diarrhoeogenic Escherichia colt.
Toxigenicity status was determined by the Elek test
, as recommended by WHO (9), and by the polymerase chain reaction (PCR), which targeted both A and B subunits of the tox gene (10).