NAME: Corynebacterium diphtheriae
SYNONYM OR CROSS REFERENCE: Diphtheria
CHARACTERISTICS: Gram positive rod, non-sporulating, non-motile, characteristic swelling at one end of bacillus (club shaped), facultative anaerobe, metachromic granules, three biotypes - gravis, mitis, intermedius; produces a toxin
PATHOGENICITY: Two types of clinical infection: nasopharyngeal and cutaneous. Main manifestation is an upper respiratory tract infection, characterized by pharyngitis, fever, malaise, swelling of the neck and headache. Hypoxia may develop due to airway obstruction by the pseudomembrane; characteristic lesion marked by patch of grayish membrane with surrounding inflammation is hallmark of cutaneous infection; many inapparent infections; late effects of toxin after 2-6 weeks include cranial, motor and sensory nerve palsies and myocarditis, endocarditis; case fatality rate of 5-10% for noncutaneous diphtheria
EPIDEMIOLOGY: Normal flora of skin and nasopharynx; disease of colder months in temperate zones, involving unimmunized children; found in adults whose immunization was neglected; in the tropics, seasonal trends are less distinct; inapparent, cutaneous and wound diphtheria cases are much more common
HOST RANGE: Humans
INFECTIOUS DOSE: Toxin is extremely potent
MODE OF TRANSMISSION: Direct respiratory or physical contact with patient or carrier; more rarely with articles soiled with discharges from lesions of infected persons; raw milk has served as a vehicle
INCUBATION PERIOD: Usually 2-5 days, occasionally longer
COMMUNICABILITY: Variable period, until virulent bacilli have disappeared from discharges and lesions (2 weeks or less); rare chronic carriers may shed organisms for 6 months or more; appropriate antibiotic therapy terminates shedding promptly
RESERVOIR: Humans
ZOONOSIS: None
VECTORS: None
DRUG SUSCEPTIBILITY: Sensitive to erythromycin and penicillin
DRUG RESISTANCE: Erythromycin-resistant isolates have been reported
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to many disinfectants - 1% sodium hypochlorite and 70% ethanol, glutaraldehyde, formaldehyde, iodines
PHYSICAL INACTIVATION: Inactivated by moist heat (121°C for at least 15 min) and dry heat (160-170°C for at least 1 hour)
SURVIVAL OUTSIDE HOST: Air - 2.5 hours; carcass - 14 days; dust -7-102 days; exudate (infectious croup membrane) - up to 150 days; contaminated wooden toy - 180 days; soil - 1 year;
SURVEILLANCE: Surveillance for lesions and formation of pseudomembrane; confirmation by culturing
FIRST AID/TREATMENT: If diphtheria is strongly suspected, antitoxin should be given without awaiting bacterial confirmation; antibiotic therapy should be administered after cultures in conjunction with antitoxin
IMMUNIZATION: Immunization in young children with diphtheria toxoid (usually combined with tetanus toxoid and pertussis vaccine - DTP); primary immunization in adults with TD; protection maintained in adults and children by administering a dose of TD every 10 years
PROPHYLAXIS: Booster dose of TD; if infected and not previously immunized, antibiotic therapy and immunization started with first dose of toxoid
LABORATORY-ACQUIRED INFECTIONS: 33 documented cases up to 1976; at least one reported since then; laboratory animal-associated infections have not been reported
SOURCES/SPECIMENS: Exudates or secretions of the nose, throat (tonsil), pharynx, larynx, wounds; blood, skin
PRIMARY HAZARDS: Inhalation of infectious aerosols and droplets; accidental parenteral inoculation; ingestion
SPECIAL HAZARDS: None
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices, containment equipment and facilities for all activities involving known or potentially infected clinical materials or cultures; animal biosafety level 2 facilities for studies utilizing infected laboratory animals
PROTECTIVE CLOTHING: Laboratory coat; gloves when direct contact with infectious materials
OTHER PRECAUTIONS: Administration of adult diphtheria-tetanus toxoid at 10-year intervals to reduce the risk to laboratory and animal care personnel of toxin exposures and work with infected materials
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with absorbent paper towel and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate before disposal; steam sterilization, chemical disinfection, incineration
STORAGE: In sealed containers that are appropriately labelled
Date prepared: January 2000
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001
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