Reemerging of Corynebacterium DiphtheriaCase Study Number FourTable #6Emerita AriasOfili OkolonwamuRomelene Juban
Patient Evaluation
Patient is a 42 year old femaleLiving in US but born in RussiaReturned to Moscow for a visit on Nov. 22Dec. 6, experienced onset of fever and sore throatHospitalized on Dec. 7Physical examination revealed a pharyngeal
membraneLab examination of membrane revealed gram
positive rodsPatient’s vaccination history is unknown
Pharyngeal Membrane
Possible Causes of Patient’s Distress
that Need to be Ruled Out: Severe streptococcal sore throatInfectious mononucleosisVincent’s anginaPharyngitisTonsillitisInfluenza
Lab Tests Need to Support an Accurate Diagnosis:Strept testCBCMonospot TestThroat and nares swab testCulture of pharyngeal membraneAlso, 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/mLInterpretation of antitoxin levels by in vitro neutralization
assay
Antitoxin level (IU/ml Interpretation
<0.01 Susceptible
0.01 Lowest level of antitoxin/some protection
0.01-0.09 Levels of antitoxin/some protection
0.1 Protecting Level of antitoxin
>1.0 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 protection-level 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 areaMoscow has a high incidence of diphtheriaDiphtheria is very contagious, transmitted by
air droplets, physical contact, even by a hand shaking
Patient not having current booster shotInadequately 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 toxinsDeterminants involved in colonization of
host-encoded by the bacteriaToxin-encoded by corynebacteriophages
Corynebacteriophage (Beta phage) that carries the tox gene
Toxin Relative Potencies
Toxin Power RatioCyanide 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.
Referenceshttp://www.astdhppe.org/infect/dip.htmlhttp://www.cdc.gov./ncidod/eid/vol5nos/http://gsbs.utmb.edu/microbook/ch032.htmhttp://www.intmed.mcw.edu/ITC/Diphthe
riaRussia.htmhttp://ncid.dcd.gov/travel/yb/utils/ybGetLebofe 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
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