Table of Contents
What morphological features are characteristic of the Corynebacterium diphtheria?
C. diphtheriae is a pleomorphic, club-shaped, Gram positive bacillus that is catalase positive, non-motile, non-spore forming, and non-acid fast. On Gram stain, the organisms are typically described as having a “picket fence” or “Chinese character” morphology (image 3).
What is the shape and grouping pattern for Corynebacterium species?
Corynebacterium (/kɔːˈraɪnəbækˌtɪəriəm, -ˈrɪn-/) is a genus of bacteria that are Gram-positive and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name (coryneform means “club-shaped”).
What is the arrangement of Corynebacterium diphtheriae?
They do not form spores or branch as do the actinomycetes, but they have the characteristic of forming irregular, club-shaped or V-shaped arrangements in normal growth. They undergo snapping movements just after cell division, which brings them into characteristic forms resembling Chinese letters or palisades.
Where does Corynebacterium colonize?
EPIDEMIOLOGY. Corynebacterium spp. can be part of the normal skin and upper respiratory tract flora and commonly colonize hospitalized patients.
Why is Corynebacterium diphtheriae club-shaped?
Diphtheria toxoid Corynebacterium diphtheriae is a slender Gram-positive bacillus, usually with one end being wider, thus giving the often-described club-shaped appearance.
Is Corynebacterium a diphtheriae bacilli?
Structure, Classification, and Antigenic Types. Corynebacterium diphtheriae is a nonmotile, noncapsulated, club-shaped, Gram-positive bacillus.
What are the different shapes and sizes of bacteria?
Individual bacteria can assume one of three basic shapes: spherical (coccus), rodlike (bacillus), or curved (vibrio, spirillum, or spirochete). Considerable variation is seen in the actual shapes of bacteria, and cells can be stretched or compressed in one dimension.
What is the hallmark lesion for Corynebacterium diphtheria?
The hallmark of respiratory diphtheria is a pseudomembrane that appears within 2–3 days of illness over the mucous lining of the tonsils, pharynx, larynx, or nares and that can extend into the trachea.
What are the two types of diphtheria?
Diphtheria is a highly contagious and potentially life-threatening bacterial disease caused by Corynebacterium diphtheriae. There are two types of diphtheria: respiratory and cutaneous. Respiratory diphtheria involves the nose, throat and tonsils, and cutaneous diphtheria involves the skin.
What are the characteristics of Corynebacterium species?
Corynebacterium spp. usually appear as opaque, white or gray colonies. They may resemble non-hemolytic or alpha-hemolytic streptococci and commensal Neisseria spp. Facultatively anaerobic. Chemoorganoheterotrophic having both a respiratory and fermentative type metabolism. Catalase-positive. Most produce acid from glucose.
What is the shape of Corynebacterium diphtheriae?
Shape – Corynebacterium diphtheriae is a Thin, slender rod-shaped (bacillus) bacterium with a tendency to clubbing at one or both the ends due to the presence of metachromatic granules which may present at one or both the ends.
Who created the genus Corynebacterium?
The genus Corynebacterium was created by Lehmann and Neumann in 1896 as a taxonomic group to contain the bacterial rods responsible for causing diphtheria.
What are the types of Corynebacterium infections?
Corynebacterium jeikeium: opportunistic infections (especially in immunocompromised patients) Corynebacterium urealyticum: urinary tract infections (UTI’s); rare but important Corynebacterium pseudotuberculosis: subacute relapsing lymphadenitis Corynebacterium ulcerans: pharnygitis