Corynebacterium diphtheria & Diphtheroids Flashcards
(12 cards)
1
Q
Corynebacterium Genus Info
A
- Over 130 species
- Club-shaped
- Non-spore forming
- Gram positive rods
- Neisser or Albert’s Stain
- Include Diphtheroids part of normal flora of skin & mucosa
2
Q
C. Diphtheriae General Info
A
- Obligate Pathogen
- Asymptomatic carriage on Skin or Oropharynx
- Spread by Respiratory Droplets
3
Q
C. Diphtheriae Morphology
A
- Gram Positive
- Club-shaped rods
4
Q
C. Diphtheriae Cultivation
A
- Easily at Aerobic conditions 37˚C
- Löffler Medium (slant agar, horse serum)
- Clauber Agar (tellurite, black)
5
Q
C. Diphtheriae Stains
A
- Neisser stain: Detects presence of metachromatic granules (volutin) turning them purple & cell yellowish
- Albert’s stain: Also stains Volutin granules
6
Q
C. Diphtheriae Virulence Factors
A
Diphtheria Toxin
- A/B toxin
- B binds heparin-binding epidermal GF-R, then toxin taken up by endocyt.
- A ribosylates EF-2, no protein synth
7
Q
C. Diphtheriae Diseases
A
- Respiratory Diphtheria: Sore throat, Lymphadenopathy (bulls neck), Pseudomembrane formation (diphtheric patch)
- Cutaneous Diphtheria
- Systemic spread causes myocarditis, arrhythmia, paralysis of oropharynx
8
Q
C. Diphtheriae Treatment
A
- Diphtheria Antitoxin
- Penicillin
- Erythromycin
- Vaccine DTaP
9
Q
C. Diphtheriae Microbiological Diagnosis
A
- ELEK’s test: Diphtheria antitoxin makes line if toxin present
- PCR of toxin gene
- Culture on Löffler’s or Clauberg
- Biochemical reactions
10
Q
C. Diphtheriae Biochemical reactions
A
- Dextrose: +
- Maltose: +
- Sucrose: -
11
Q
Diphtheroids info
A
- Normal flora of skin & mucosa
- Gram Positive rods
- Non-spore forming
- No metachromatic Granule in staining
12
Q
Diphtheroids Examples
A
- C. Jeikeium (nosocomial)
- C. Urealyticum (UTI)
- C. Ulcerans (zoonosis)
- C. Minutissimum (erythrasma axilla/pubic)
- C. Pseudodiphtheriticum
