Aerobic and anaerobic gram positive bacteria

• complete the diagram:

  A) non spore former

  B) spore former

  C) Bacillus

  D) bacillus spp

  E) bacillus anthracis

  F) branching

  G) nocardia gordonia tsukamurella rhodococcus streptomyces

  H) catalase

  I) Corynebacterium listeria

  J) motility 22'c bile esculin hydrolysis

  K) listeria

  L) Corynebacterium

  M) h2s production

  N) erysipelothrix

  O) arcanobacterium gardnerella vaginalis lactobacillus

  P) beta hemolytic motile

  
• NON-SPORE-FORMING, NON-BRANCHING, CATALASE-POSITIVE BACILLI

  • Corynebacterium
  • Rothia
  • Listeria
• Corynebacterium is also called - Kleb Loeffler’s bacillus
• Corynebacterium - Slightly curved, gram-positive rods with nonparallel sides and slightly wider ends, producing the described
• Corynebacterium is “club shape” or coryneform
• Coryne – means “club” or “club-shaped rods”
• Diptheroid meaning “diphtheria-like”
• Corynebacterium Can be divided into non-lipophilic and lipophilic species
• fastidious - organisms that are difficult to grow; grow slowly on standard culture media
• Lipophilic Corynebacteria – fastidious; cultures must be incubated for at least 48 hours before the growth to be detected
• lipophilic organism, the growth is enhanced if lipids are included in the culture media
• Diphtheria toxin - virulence factor of Corynebacterium Diptheriae
• Diphtheria toxin - a heat - labile, major virulence factor of Corynebacterium diphtheriae
• Diphtheria toxin - This toxin is produced by strains of Corynebacterium diphtheriae infected with a lysogenic b-phage, which carries the gene tox for diphtheria toxin.
• Diphtheria toxin is Protein of 62,000 daltons (Da)
• 2 fragment of Diphtheria toxin

  1. Fragment A
  2. Fragment B
• Fragment A – Diphtheria toxin fragment responsible for the cytotoxicity
• Fragment B – Diphtheria toxin fragment responsible for binding to receptors on human cells; mediates the entry of fragment A into the cytoplasm
• clinical infection of Corynebacterium diphtheriae

  1. Respiratory diphtheria
  2. Cutaneous diphtheria
• Respiratory diphtheria: sudden onset with exudative pharyngitis, sore throat, low-grade fever, and malaise; a thick pseudomembrane develops over the pharynx; in critically ill patients, cardiac and neurologic complications are most significant
• Respiratory diphtheria mode of transmission is through aerosol, through nasopharyngeal route, or nasal-oral discharges
• Respiratory diphtheria Exotoxin can lead to the pseudomembrane formation
• Respiratory diphtheria Patients that has respiratory diphtheria are characterized as having “bull’s neck” appearance [usually develops on the oropharynx]
• Cutaneous diphtheria: a papule can develop on the skin, which progresses to a non-healing ulcer; systemic signs can develop. [lesions on the skin]
• LABORATORY DIAGNOSIS of CORYNEBACTERIUM DIPHTHERIA [MICROSCOPY]

  • Highly pleomorphic gram-positive bacillus
  • Palisades (cells lie in parallel rows) or as individual cells lying at sharp angles to another in “V” and “L” formations.
  • Club-shaped swellings and beaded forms are common
  • Often stain irregularly, especially when stained with methylene blue
  • The metachromatic areas of the cell: Babès-Ernst granules
• Babès-Ernst granules represents the accumulation of polymerized polyphosphates
• LABORATORY DIAGNOSIS OF CORYNEBACTERIUM DIPHTHERIA [CULTURE CHARACTERISTICS]

  • Facultative anaerobe - aerotolerance
  • Optimal growth temperature of 37°C
  • Multiplication occurs within the range of 15°C to 40°C
  • Grows on nutrient agar
  • Loeffler serum or Pai agars [medium contain blood or serum] - Morphology of the organism is demonstrated
  • Have a very small zone of beta hemolysis
  • Cystine-tellurite blood agar (CTBA)
  • Selective and differential culture media
  • Presence of potassium tellurite – inhibits many non-coryneform bacteria
• Modification of the tindsdale medium [contains sheep red blood cells, bovine serum, cysteine, and potassium tellurite]
• CTBA: black or brownish colonies [due to the reduction of tellurite]
• Corynebacterium diphtheriae, Corynebacterium ulcerans, Corynebacterium pseudotuberculosis – only ones that form brown halos as a result of the cysteinase activity.
• LABORATORY DIAGNOSIS OF CORYNEBACTERIUM DIPHTHERIA [IDENTIFICATION]

  • Catalase positive
  • Non-motile - motility
  • organism that produce brown halo on CTBA
  • Corynebacterium diphtheriae
  • Corynebacterium ulcerans
  • Corynebacterium pseudotuberculosis
• Characteristics of Corynebacterium diphtheriae

  • Lacks urease production
  • Ferments glucose and maltose
  • Producing acid, but not gas
  • Reduces nitrate to nitrite
• In Vitro - TEST FOR TOXIGENITY for CORYNEBACTERIUM DIPHTHERIA
• ELEK TEST – immunodiffusion test [in the culture media, we are going to streak the organism (low iron content culture media). Each organism will be streaked in a straight line parallel to each other (usually 10 mm apart). A filter paper strip with diphtheria anti-toxin will be placed on the center. Incubate it. Observe for the lines of precipitation.
• positive results for elek test - lines of precipitation
• Diphtheria is treated by prompt administration of anti-toxin
• Drug of choice for C. diphtheriae: Penicillin
• Erythromycin – treatment used for penicillin-sensitive individuals
• complete the table

  A) gram stain

  B) gram stain

  C) urease

  D) acid from starch or glycogen

  E) Corynebacterium diphtheriae

  F) corynebacterium ulcerans

  G) corynebacterium pseudotuberculosis

  H) staphylococcus spp and streptococcus spp

  I) other corynebacterium spp

  
• OTHER CORYNEBACTERIA

  • Corynebacterium amycolatum
  • Corynebacterium jeikeium
  • Corynebacterium pseudodiphtheriticum
  • Corynebacterium pseudotuberculosis
  • Corynebacterium striatum
  • Corynebacterium ulcerans
  • Corynebacterium urealyticum