Reemerging of
Corynebacterium Diphtheria
Case Study Number Four
Table #6
Emerita Arias
Ofili Okolonwamu
Romelene Juban
Patient Evaluation
Patient is a 42 year old female
Living in US but born in Russia
Returned to Moscow for a visit on Nov. 22
Dec. 6, experienced onset of fever and sore
throat
Hospitalized on Dec. 7
Physical examination revealed a pharyngeal
membrane
Lab examination of membrane revealed gram
positive rods
Patient’s vaccination history is unknown
Pharyngeal Membrane
Possible Causes of Patient’s Distress
that Need to be Ruled Out:
Severe streptococcal sore throat
Infectious mononucleosis
Vincent’s angina
Pharyngitis
Tonsillitis
Influenza
Lab Tests Need to Support an
Accurate Diagnosis:
Strept test
CBC
Monospot Test
Throat and nares swab test
Culture of pharyngeal membrane
Also, the collection of patient’s data
indispensable:
Patient details, clinical details, contact list, and
traveling history.
Toxigenic Corynebacterum diphtheria
biotype gravis was isolated from the
pharyngeal culture received on Dec. 9

Patient’s Antitoxin Level by Neutralization Assay
Measured at >5 IU/mL
Interpretation of antitoxin levels by in vitro neutralization
assay
Antitoxin level (IU/ml
Interpretation
<0.01
0.01
0.01-0.09
0.1
>1.0
Susceptible
Lowest level of antitoxin/some protection
Levels of antitoxin/some protection
Protecting Level of antitoxin
Level of antitoxin /long term protection
ELISA (EIA) Level for Specific
Human Antibodies was <0.03 IU/ml
Titer (enzyme immunoassay) revealed
that patient had immune response
showing a level of long term protectionlevel due to immune response
Although vaccination history was
unknown, neutralization assay helped
determined that patient was immunize at
certain point
Why Did Patient Contracted
Disease
Traveling to an endemic area
Moscow has a high incidence of diphtheria
Diphtheria is very contagious, transmitted by
air droplets, physical contact, even by a hand
shaking
Patient not having current booster shot
Inadequately immunized-not fully protected
What Accounts for C. diphtheria
Capable of Producing Toxins
Gram positive, fermentative, pleomorphic
rod
Four biotypes: var gravis, var mitis, var
intermedius, and var belfanti
All biotypes, except var belfanti produce
lethal exotoxins.
Pathogenesis based upon two
determinants
Determinants of C. diphtheria
pathogenesis
Ability to colonize the nasopharyngeal
cavity or the skin
Ability to produce diphtheria toxins
Determinants involved in colonization of
host-encoded by the bacteria
Toxin-encoded by corynebacteriophages
Corynebacteriophage (Beta
phage) that carries the tox gene
Toxin Relative Potencies
Toxin
Power Ratio
Cyanide
1
Curare
20
Alfatoxin
25
Snake Venom
167
Diphtheria Toxin
108
Botulinum A Toxin
3.3 x 108
Patient’s Treatment and Prognosis
¤ Patient received 40,000 IU of diphtheria
antitoxin
¤ Penicillin G for six days
¤ Roxithromycin, same as erythromycin in US,
for several days
¤ Delay in treatment can result in death or long
term disease
¤ Patient fully recovered with no complications
¤ May continue to harbor the bacteria in nose, or
throat
¤ Patient’s family and contacts to be checked to
prevent possible recurrences
Could an Epidemic of Diphtheria Occur in
United States?
1990-1994 Outbreak in Russian Federation;
>157,000 cases and 5,000 deaths
Diphtheria can cause epidemic disease in
developed countries like U.S. despite high
vaccination coverage rate in children
Prevalence studies in U.S. show 30% -60%
adults with antitoxin levels below protection
levels
Last cases of diphtheria in U.S.- drug and
alcohol abusers
Diphtheria remains endemic in developing
countries-potential source of entry into the U.S.
References
http://www.astdhppe.org/infect/dip.html
http://www.cdc.gov./ncidod/eid/vol5nos/
http://gsbs.utmb.edu/microbook/ch032.htm
http://www.intmed.mcw.edu/ITC/Diphthe
riaRussia.htm
http://ncid.dcd.gov/travel/yb/utils/ybGet
Lebofe J. Michael. “A Photographic Atlas for
the 3rd Edition Microbiology Laboratory.”
Englewood, Colorado:Morton Publishing
Company, Copyright 2005
Sanford, P. Jay M.D. “The Sanford Guide to
Antimicrobial Therapy 2006 36th Edition.”
VA:Antimicrobial Therapy, Inc. 1969