Everything You Need to Know About Corynebacterium diphtheriae

Introduction Corynebacterium

Non-spore-forming gram-positive bacilli.  Corynebacterium species tend to be clubbed or irregularly shaped- Chinese lettering arrangement,  These bacteria have a high guanosine plus cytosine content Are members of the normal flora of skin and mucous membranes of humans.  Other corynebacteria are found in animals and plants. Toxin-producing one is pathogenic. Corynebacterium diphtheriae is the most important member of the group, as it can produce a powerful exotoxin that causes diphtheria in humans.  C. ulcerans and several commensals (diphtheroides) normally colonize the skin, nasopharynx, oropharynx, GIT and UGT. Virulence factors: All toxigenic C diphtheriae are capable of elaborating the same disease-producing exotoxin. Diphtheria is caused by toxin-producing strains of C. diphtheriae.

What is diphtheriae

C. diphtheriae is non-capsulate, non-motile Individual corynebacteria in stained smears tend to lie parallel or at acute angles to one another, true branching is rarely observed in cultures. Arranged in angular fashion like Chinese lettering or cuneiform arrangement. Non-spore-forming gram-positive bacilli, Are members of the normal flora of skin and mucous membranes of humans, other Corynebacterium are found in animals and plants. Genus has two important pathogens C.difteria and C. ulcerans.

What is disease caused Corynebacterium diphtheriae?

Diphtheria is an acute and highly contagious a bacterial infection that primarily affects the respiratory system.it can also affect other parts of the body, such as the skin, ayes, and genitals. Diphtheria is caused   by diphtheriae diphtheriae, it releases a toxin that can cause severe damage to tissues and organs.  Characterized by the formation of a thick, grayish –white membrane in the throat, nose, and tonsils. The diphtheria toxin gene is encoded by a bacteriophage found in toxigenic strains, integrated into the bacterial chromosome. It is gram positive bacilli with club-like thickenings on their ends, seen at an angle with each other.  Tellurite blood agar is a selective medium used for isolation and cultivation of cornybacterium species.  Symptoms: sudden onset of sore throat and fever, swollen and tender lymph nodes in the neck, white or grayish-patches or membrane in the throat, nose, and tonsils, difficult swallowing and breathing, and cardiac complication. Transmission: person to person through respiratory droplets, contaminated food and water, and close contact with an infected person.

What causes diphtheria?

Diphtheria is caused by the bacterium cornybacterium diphtheriae. The bacterium is spread from person to person through respiratory droplets, such as those produced when an infected person coughs or sneezes. It can also be spread through contact with contaminated surfaces or objects, such as toys, clothing, or bedding.

What are the complications associated with diphtheria?

Diphtheria can cause a variety of complications, some of which can be severe or even life-threatening. Difficulty breathing: the toxin produced by the bacteria can cause the airways to become inflamed and narrow, making it difficult to breathe. Heart damage: the toxin can also damage the heart muscle, leading to an irregular heartbeat or even heart failure. Nerve damage: in severe cases, the toxin can damage the nerves, causing paralysis or other neurological problems.

Virulence factor:

All toxigenic C diphtheriae are capable of elaborating the same disease-producing exotoxin. Diphtheria is caused by toxin-producing strains of C. diphtheriae.

Pathogenesis

C. diphtheriae causes Nasal, nasopharyngeal and tonsillar diphtheria, especially in young children often there is marked edema of the neck, Infection is by inhaling respiratory droplets. Cutaneous (skin) diphtheria usually develops when C. diphtheriae infects open wounds. Exotoxin: virulent strains of C. diphtheriae produce a powerful exotoxin that is absorbed through the damaged mucous membrane into the blood circulation. If not neutralized by antitoxin, the toxin can cause toxaemia with fatal cardiac and neural complications. Exotoxin production is dependent on a particular bacteriophage possessed by virulent strains of C. diphtheriae.

Diagnosis

Specimens: Include throat, and, or nasopharyngeal swabs to confirm a diagnosis of throat diphtheria, and a skin swab if cutaneous diphtheria is suspected. Microscopy:  C. diphtheriae is Gram positive but usually stains unevenly and weakly,  It is markedly pleomorphic,  Long, thin, and curved forms can be seen } short rods and rods enlarged at one end (clubshaped). They often appear in clusters, joined at angles like Chinese letters. Culture: C. diphtheriae is an aerobe and facultative anaerobe. Temperature range for growth is 20–40 ºC with an optimum of 35–37 ºC. Loeffler serum medium and Dorset egg medium:  C. diphtheriae grows rapidly on these media, producing significant growth in 4–6 hours. Biochemical tests: All C. Diphtheriae reduces nitrate to nitrites, Toxigenic strain of C. Diphtheriae is Catalase and Oxidase negative, Urease negative, Ferments glucose and maltose with acid production, A few strains of gravis and mitis biovars ferment sucrose and C. diphtheriae gravis ferments starch with acid production.

Haw to treatment C. diphtheriae

Antimicrobial drugs (Penicillin or Erythromycin) and early administration of specific antitoxin against the toxin formed by the organisms at their site of entry and multiplication.

Prevention

•  Active immunization

•  Passive immunization

•  Combined immunization

Conclusion

Corynebacterium diphtheriae is a pathogenic bacterium that causes diphtheria, a serious respiratory disease. It produces a potent toxin that damages tissues and organs. Early diagnosis, antitoxin treatment, and vaccination are essential for prevention and control.