<p><b>OBJECTIVE</b>To clarify the
diagnosis of one suspected case of
diphtheria in Guangdong province by epidemiological
analysis and etiologic
detection.</p><p><b>
METHODS</b>On July 6th 2010, the
corynebacterium diphtheria was detected from the nasal
secretions of one
nasopharyngeal carcinoma patient in a college-town
hospital in Guangzhou City, Guangdong Province. The
patient and the close contacts were asked to participate in the epidemiological
survey; and their nasopharyngeal swabs (3 samples) and the nasal
secretions of the
patient (1 sample) were collected. The
bacteria of the samples were isolated and cultured by
blood plate and
agar loefflera. The smears of positive
strains were dyed and identified by BioMerieux
API Coryne biochemical card.
Gene tox of β-Corynebacteriophage,
Corynebacterium diphtheriae was tested by
PCR method, the
aliphatic acid was analyzed by
gas chromatography method and the
Corynebacterium diphtheriae (CMCC 38009) was selected as positive control.</p><p><b>RESULTS</b>The
patient had not gone out, neither had been visited. The
patient denied
history of
vaccines or the
immunizations. From the
survey on
patient's
family members and close contacts, no
similar symptoms had been found. One
strain of
Corynebacterium diphtheriae was isolated from the
patient's nasal
secretions, Gram positive and shape diversified. After cultured by
agar loefflera and Gram-dyed and Neisser-dyed, one end or both two ends of the
strain showed typical metachromatic granule.
API Coryne was identified to
Corynebacterium diphtheriae mitis/belfanti (99.4%). The result of
gas chromatography method also indicated
Corynebacterium diphtheriae. No
Corynebacterium diphtheriae was isolated from the nasopharyngeal swabs, neither of the
patient nor of the close contacts. The
gene tox of β-Corynebacteriophage,
Corynebacterium diphtheriae was negative according to the
PCR test.</p><p><b>CONCLUSION</b>The isolated
Corynebacterium diphtheriae did not produce toxin as there was no
biological structure
gene of toxin. The
patient was a
health carrier of nontoxic
Corynebacterium diphtheriae.</p>