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Corynebacterium

Corynebacteria are gram-positive Gram-Positive Penicillins, club-shaped bacilli Bacilli Shigella. Corynebacteria are commonly isolated on tellurite Tellurite Diphtheria or Loeffler's media and have characteristic metachromatic granules. The major pathogenic species is Corynebacterium diphtheriae Corynebacterium diphtheriae Diphtheria is an infectious disease caused by corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria, which causes diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria—a severe upper respiratory infection Upper respiratory infection Rhinitis. The characteristic findings of diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria include pharyngeal pseudomembranes Pseudomembranes Raised yellow or off-white plaques up to 2 cm in diameter that form as a result of mucosal ulceration Pseudomembranous Colitis (grayish tonsillar exudates), severe pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis, and “bull’s neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy. Treatment is primarily through passive immunization Passive immunization Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (adoptive transfer). Vaccination with antitoxin and antibiotics. Prevention is via the diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria toxoid Toxoid Preparations of pathogenic organisms or their derivatives made nontoxic and intended for active immunologic prophylaxis. They include deactivated toxins. Anatoxin toxoids are distinct from anatoxins that are tropanes found in cyanobacteria. Vaccination vaccine Vaccine Suspensions of killed or attenuated microorganisms (bacteria, viruses, fungi, protozoa), antigenic proteins, synthetic constructs, or other bio-molecular derivatives, administered for the prevention, amelioration, or treatment of infectious and other diseases. Vaccination.

Last updated: 4 Jun, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Classification

Microbiology flowchart gram-positive bacteria classification

Gram-positive Gram-Positive Penicillins bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology:
Most bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology can be classified according to a lab procedure called Gram staining Gram staining Bacteriology.
Bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology with cell walls that have a thick layer of peptidoglycan Peptidoglycan Penicillins retain the crystal violet stain utilized in Gram staining Gram staining Bacteriology but are not affected by the safranin counterstain. These bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology appear as purple-blue on the stain, indicating that they are gram positive Gram positive Bacteria which retain the crystal violet stain when treated by gram’s method. Nocardia/Nocardiosis. The bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology can be further classified according to morphology (branching filaments, bacilli Bacilli Shigella, and cocci Cocci Bacteriology in clusters or chains) and their ability to grow in the presence of oxygen (aerobic versus anaerobic). The cocci Cocci Bacteriology can also be further identified. Staphylococci can be narrowed down on the basis of the presence of the enzyme coagulase Coagulase Enzymes that cause coagulation in plasma by forming a complex with human prothrombin. Coagulases are produced by certain staphylococcus and yersinia pestis. Staphylococci produce two types of coagulase: staphylocoagulase, a free coagulase that produces true clotting of plasma, and staphylococcal clumping factor, a bound coagulase in the cell wall that induces clumping of cells in the presence of fibrinogen. Staphylococcus and on their sensitivity Sensitivity Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Blotting Techniques to the antibiotic novobiocin. Streptococci are grown on blood agar Blood agar Nocardia/Nocardiosis and classified on the basis of which form of hemolysis they employ (α, β, or γ). Streptococci are further narrowed on the basis of their response to the pyrrolidonyl-β-naphthylamide (PYR) test, their sensitivity Sensitivity Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Blotting Techniques to specific antimicrobials (optochin and bacitracin), and their ability to grow on sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia chloride Chloride Inorganic compounds derived from hydrochloric acid that contain the Cl- ion. Electrolytes (NaCl) media.

Image by Lecturio. License: CC BY-NC-SA 4.0

General Characteristics

Basic features

General characteristics of Corynebacterium species include:

Micrograph of corynebacterium diphtheriae

Micrograph of Corynebacterium diphtheriae Corynebacterium diphtheriae Diphtheria is an infectious disease caused by corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria

Image: “12163” by the CDC/Graham Heid. License: Public domain.

Growth and biochemical properties

  • Catalase Catalase An oxidoreductase that catalyzes the conversion of hydrogen peroxide to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in acatalasia. Nocardia/Nocardiosis positive (split hydrogen peroxide Hydrogen peroxide A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials. Myeloperoxidase Deficiency into water and oxygen)
  • Oxidase Oxidase Neisseria negative, indole negative
  • Ferment glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance, starch, and glycogen
  • Grow well at 37°C (98.6°F) on blood or serum-containing media:

Clinically relevant species

  • C. diphtheriae: 
    • Major pathogenic species
    • Causes diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria ( pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis and cutaneous forms)
  • Non-diphtherial Corynebacterium (diphtheroids):
    • Mostly contaminants
    • May be pathogenic, especially in immunocompromised immunocompromised A human or animal whose immunologic mechanism is deficient because of an immunodeficiency disorder or other disease or as the result of the administration of immunosuppressive drugs or radiation. Gastroenteritis hosts
    • C. minutissimum:
      • Normal skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions inhabitant
      • Can cause erythrasma: superficial infection of intertriginous areas Intertriginous areas Malassezia Fungi
    • Many species cause diseases in domestic animals Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, animalia was one of the kingdoms. Under the modern three domain model, animalia represents one of the many groups in the domain eukaryota. Cell Types: Eukaryotic versus Prokaryotic.

Corynebacterium diphtheriae

Epidemiology

  • In immunized individuals, the rate is low: < 5 per 100,000.
  • Remains endemic in certain parts of the world (Brazil, Nigeria, India, certain parts of the former Soviet Union)
  • No racial or sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria predilection
  • Can affect Affect The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves. Psychiatric Assessment children and adults

Transmission

  • Humans are the only known reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli.
  • Airborne droplets Droplets Varicella-Zoster Virus/Chickenpox
  • Direct contact with respiratory secretions
  • Contact with skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions lesions
  • Can be transmitted by immunized and asymptomatic carriers Carriers The Cell: Cell Membrane

Virulence factors Virulence factors Those components of an organism that determine its capacity to cause disease but are not required for its viability per se. Two classes have been characterized: toxins, biological and surface adhesion molecules that affect the ability of the microorganism to invade and colonize a host. Haemophilus

  • Not an invasive organism
  • Pathogenicity is based on diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria toxin (exotoxin):
    • Only produced if lysogenized by a β-bacteriophage
    • Has 2 subunits:
      • A—active
      • B—binding
    • B binds to the cell membrane Cell Membrane A cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane and A enters the cell.
    • Ribosylation of elongation Elongation Polymerase Chain Reaction (PCR) factor ( EF EF Cardiac Cycle-2)
    • Inhibits protein synthesis Synthesis Polymerase Chain Reaction (PCR)
    • Causes cell death Cell death Injurious stimuli trigger the process of cellular adaptation, whereby cells respond to withstand the harmful changes in their environment. Overwhelmed adaptive mechanisms lead to cell injury. Mild stimuli produce reversible injury. If the stimulus is severe or persistent, injury becomes irreversible. Apoptosis is programmed cell death, a mechanism with both physiologic and pathologic effects. Cell Injury and Death

Clinical presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor

Diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria (respiratory):

  • Sore throat Throat The pharynx is a component of the digestive system that lies posterior to the nasal cavity, oral cavity, and larynx. The pharynx can be divided into the oropharynx, nasopharynx, and laryngopharynx. Pharyngeal muscles play an integral role in vital processes such as breathing, swallowing, and speaking. Pharynx: Anatomy, malaise Malaise Tick-borne Encephalitis Virus, cervical lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy, low-grade fever Low-Grade Fever Erythema Infectiosum
  • Pharyngeal erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion with spots of white and gray exudate Exudate Exudates are fluids, cells, or other cellular substances that are slowly discharged from blood vessels usually from inflamed tissues. Pleural Effusion
  • Can also have nasal, laryngeal, and tracheobronchial forms
  • Pseudomembranes Pseudomembranes Raised yellow or off-white plaques up to 2 cm in diameter that form as a result of mucosal ulceration Pseudomembranous Colitis:
    • Form in ⅓ of cases
    • Composed of fibrin Fibrin A protein derived from fibrinogen in the presence of thrombin, which forms part of the blood clot. Rapidly Progressive Glomerulonephritis, necrotic debris, inflammatory cells, and organisms
    • Tightly adherent to underlying tissue; bleeds with scraping
    • Can spread to any portion of the respiratory tract
  • “Malignant diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria”:
  • Exam tip: A common question stem may include an immigrant with a sore throat Throat The pharynx is a component of the digestive system that lies posterior to the nasal cavity, oral cavity, and larynx. The pharynx can be divided into the oropharynx, nasopharynx, and laryngopharynx. Pharyngeal muscles play an integral role in vital processes such as breathing, swallowing, and speaking. Pharynx: Anatomy; physical exam reveals tonsils Tonsils Tonsillitis with grayish exudate Exudate Exudates are fluids, cells, or other cellular substances that are slowly discharged from blood vessels usually from inflamed tissues. Pleural Effusion.

Complications/systemic toxemia:

  • Cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR):
    • Myocarditis Myocarditis Myocarditis is an inflammatory disease of the myocardium, which may occur alone or in association with a systemic process. There are numerous etiologies of myocarditis, but all lead to inflammation and myocyte injury, most often leading to signs and symptoms of heart failure. Myocarditis
    • Arrhythmias
  • Neurologic:
  • Renal: renal failure Renal failure Conditions in which the kidneys perform below the normal level in the ability to remove wastes, concentrate urine, and maintain electrolyte balance; blood pressure; and calcium metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of proteinuria) and reduction in glomerular filtration rate. Crush Syndrome from hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension or direct exotoxin effects

Cutaneous (wound) diphtheria Diphtheria Diphtheria is an infectious disease caused by Corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria:

Identification Identification Defense Mechanisms

  • Cultures Cultures Klebsiella:
    • Should be obtained from throat Throat The pharynx is a component of the digestive system that lies posterior to the nasal cavity, oral cavity, and larynx. The pharynx can be divided into the oropharynx, nasopharynx, and laryngopharynx. Pharyngeal muscles play an integral role in vital processes such as breathing, swallowing, and speaking. Pharynx: Anatomy or nose Nose The nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Nose and Nasal Cavity: Anatomy, including a portion of membrane
    • Cultured on Loeffler’s Loeffler’s Diphtheria or tellurite Tellurite Diphtheria media
  • Toxin detection:

Prevention

  • Toxoid Toxoid Preparations of pathogenic organisms or their derivatives made nontoxic and intended for active immunologic prophylaxis. They include deactivated toxins. Anatoxin toxoids are distinct from anatoxins that are tropanes found in cyanobacteria. Vaccination vaccine Vaccine Suspensions of killed or attenuated microorganisms (bacteria, viruses, fungi, protozoa), antigenic proteins, synthetic constructs, or other bio-molecular derivatives, administered for the prevention, amelioration, or treatment of infectious and other diseases. Vaccination
  • Infants are protected by maternal antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions.

Management

  • Passive immunization Passive immunization Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (adoptive transfer). Vaccination or anti-toxin: 1st line
  • Antibiotics: Erythromycin Erythromycin A bacteriostatic antibiotic macrolide produced by streptomyces erythreus. Erythromycin a is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50s ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. Macrolides and Ketolides or penicillin Penicillin Rheumatic Fever are the 1st choices for 14 days.
  • Supportive management: 

Mnemonic

ABCDEFGs of Corynebacterium diphtheriae Corynebacterium diphtheriae Diphtheria is an infectious disease caused by corynebacterium diphtheriae that most often results in respiratory disease with membranous inflammation of the pharynx, sore throat, fever, swollen glands, and weakness. The hallmark sign is a sheet of thick, gray material covering the back of the throat. Diphtheria:

  • ADP-ribosylation
  • β-bacteriophage
  • Corynebacterium
  • Diphtheriae
  • Elongation Factor 2 ( EF EF Cardiac Cycle-2)
  • Granules

References

  1. Barroso L.F., & Pegram P.S. (2020). Clinical manifestations, diagnosis, and treatment of diphtheria. UpToDate. Retrieved December 28, 2020, from https://www.uptodate.com/contents/clinical-manifestations-diagnosis-and-treatment-of-diphtheria?search=diphtheria&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H11
  2. Barroso L.F., & Pegram P.S. (2019). Epidemiology and pathophysiology of diphtheria. UpToDate. Retrieved December 28, 2020, from https://www.uptodate.com/contents/epidemiology-and-pathophysiology-of-diphtheria?search=diphtheria&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2
  3. Frassetto, L.A. (2019). Corynebacterium Infections Treatment & Management. https://emedicine.medscape.com/article/215100-treatment
  4. Nisha R. (2020). Corynebacterium diphtheriae: Properties, Pathogenesis, and Lab Diagnosis. https://microbeonline.com/corynebacterium-diphtheriae-properties-pathogenesis-diagnosis/

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