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Microbial Pathogens: Listeria, Erysipelothrix & Corynebacterium

Learn about the classification, microbiology, clinical syndromes, epidemiology, and treatment of Listeria, Erysipelothrix, and Corynebacterium infections. Understand the life cycle, diagnostic methods, and complications associated with these bacteria. Stay informed on identifying and managing infections caused by these microbial pathogens.

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Microbial Pathogens: Listeria, Erysipelothrix & Corynebacterium

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  1. ListeriaandErysipelothrix Ali SomilyMD

  2. Classification • Genus listeria • Soil , water, and vegetation • Many species? • L.ivanovia ( animal) • L.innocua ( food) • L.monocytogen • Pathogenic to human

  3. Microbiology • Specimen • Blood • CSF • Amniotic fluid • Non sterile site • Vagina • Stool spp not swab • 1-5% carrier • Media • BAP • CHO • Temp • Cold enrichment for several days

  4. Microbiology • Smear • Aerobic non spore forming short G+ve B or coccobacilli • Rounded end , singly or short chain • In CSF might mimic • Enterococcus • S.pneumoniae • Corynebacterium • Haemophilus • Culture • Catalase +ve • H2S –ve

  5. Listeria monocytogenes

  6. Clinical syndromes • Epidemiology • Summer month • Epidemic& sporadic • Dairy product & meat • Predisposing factors • Newborn • Elderly • Pregnancy • Cell mediated Abn. • AIDS • Lymphoma • Transplant • Diseases • Septcemia • CNS (meningitis, encephalitis) • AmnionitisPreg. Termination

  7. Life Cycle

  8. Treatment • Ampicillin not cefotaxime

  9. Erysipelothrixs rhusiopathiae • Genus Erysipelothrixs • Two spp • E. rhusiopathiae (only pathogen) • E.tonsillarum

  10. Microbiology • Smear • Gram positive nonspore forming short baccilli, • Rounded end singly or short chain • Slender and long filaments

  11. Microbiology • All -ve • Catalase • Oxidase • H2S +ve

  12. E. rhusiopathiae • Carried by animal (fish, Swine) • Cutaneous infection Erysipeloid • Skin abrasion, injury bite from infected animal. • Hand of veterinarians butchers and fish handlers • Generalized rare • I’C (bacteremia and endocarditis)

  13. Erysipeloid

  14. Corynebacterium

  15. Coryneform • Aerobic non spore forming gram positive bacilli • Coryne= clubcoynebacterium • >40 spp devided into 3 groups • Group I human and animal • Group II plant • Group III nonpathogenic • C.dipthteriae • Archanobacterium • Gardnerella

  16. Microbiology • Smear • Vary from coccoid to rod .Clubbed stain unevenly Arrange in V-shape Chinese letter .Rod in parallel or palisade formation • C.diphtheria • Nasopharyngeal swab • BAP • Selective media • Tellurite medium( black colonies) • Tinsdale • Cystine –tellurite BAP • Sensitive to K tellurite may not grow • Loeffler’ s media not as primary mediametachromatic granules

  17. Identification • Catalase +VE • APICoryne • RapID CB plus • Toxigenicity • Elek test reference lab • Antisera on strep under special media • Neg and pos control in addition to the patientsample • Incubate 37d • 45o line of precipitation • Reincubate 72 hr if negative

  18. C. diphtheriae

  19. VARIENT OF C.DIPHTHERIA: • GRAVIS • MITIS • INTERMEDIUS

  20. COLONIAL MORPHOLOGY

  21. TINSDAL MEDIA

  22. TINSDAL MEDIA

  23. (i) C. diphtheriae biotype gravis colonies on a Tinsdale agar plate

  24. Recovery of Miscellaneous Pathogens From Throat Cultures • Pseudomembrane of the pharynx • Occasionally of the skin. • Toxigenic strains of Corynebacterium. • To confirm a clinical diagnosis of diphtheria, the strain isolated diphtheriae. • The disease is characterized must be shown to produce toxin.

  25. Clinical infections • Respiratory and cutaneous • Uncommon in North America and Western Europe. • Humans are the only natural hosts for C. diphtheriae. • Carried in the upper respiratory tract • Spread by droplet infection or hand-tomouth contact. • IP 2 to 5 days. • Low-grade fever, malaise, and a mild sore throat. • Tonsils or pharynx.

  26. Rapidly multiply on the epithelial cells and trigger an inflammatory reaction. • The infecting toxigenic strain of C. diphtheriae produces toxin locally • Tissue necrosis and exudate formation. • Cell necrosis and exudate forms a very tough gray to white pseudomembrane, which attaches to the tissues. • Spread downward into the larynx and trachea. • Suffocation if the membrane spreads

  27. Blocks the air passage or if it is dislodged • The toxin also is absorbed and produces a variety of systemic effects. • Kidneys, heart, and nervous system • Death often is a result of cardiac failure. • Another effect of the toxin is a demyelinating peripheral neuritis paralysis following the acute illness • Mortality of 5-10%, highest in very young and old. • Erythromycin is the drug used for penicillin-sensitive individuals.

  28. Antitoxin • Produced in horses. • Hypersensitivity to horse serum precludes its administration. • 10% allergic reaction to the horse serum. • Antibiotics have no effect on toxin • Eliminate the focus of infection as well as prevent the spread of the organism. • The drug of choice is penicillin.

  29. Nonrespiratory sites • Cutaneous • Systemically, but systemic complications are less common than from upper respiratory infections.

  30. The routine immunization • Diphtheria, pertussis, tetanus, polio : • 2,4,6,18 months, 4 yrs • Routine immunization since 1950's - one or two cases a year, classic diptheria rare • Since 1990, thousands of cases in former Soviet Union (mortality 3-23%)

  31. Diptheria-vaccine • Toxoid; cell-free detoxified diphtheria toxin protects against the systemic effects of toxin but not against local infection/colonization

  32. Diphtheria toxin/Zoonotic • C.ulceran • Bovine mastitis • C.pseudotuberculosis • Animal(sheep) LNs

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