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bacteria

clinically important bacteria

clinical classification of bacteria

Gram -ve rods:

  • mainly belong to Enterobacteriaceae family & are non-fastidious, facultative anaerobes with fermentative metabolism, oxidase negative, bile tolerant, & if motile then have peritrichous flagella
  • obligate anaerobes:
    • bacteroidaceae (non-sporing)
    • bacteroides (mixed acid f. glucose)
    • fusobacterium (butyric acid mainly f. glucose)
    • leptotrichia (lactic acid mainly f. glucose)
  • facultative anaerobes:
    • oxidase negative:
      • enterobacteriaceae (ferm., non-fastidious)
        • Escherichia (acid f.lactose)
        • Edwardsiella
        • Citrobacter (acid f.lactose)
        • Salmonella (ONPG neg, urea neg; mannitol→gas)
        • Shigella (ONPG neg, urea neg; mannitol→no gas)
        • Klebsiella (acid f. lactose)
        • Enterobacter (acid f. lactose)
        • Serratia
        • Proteus (ONPG neg. urea pos.)
        • Providencia
        • Erwinia
        • actinobacillus (ferm., pleomorphic fastidious)
    • oxidase positive:
      • fermentative:
        • Vibrio
        • Aeromonas
        • Pasteurella
        • Plesiomonas
  • oxidative
    • Flavobacterium (variably fac.anaer.)
  • obligate aerobes:
    • Pseudomonas (oxidase +ve, not ferment.)
    • Xanthomonas
    • Alcaligenes (oxidase +ve, alkali producing)
  • fastidious

Gram -ve coccobacilli:

  • facultative anaerobes
    • Haemophilus (fastid.,)
  • obligate aerobes
    • Brucella (fastid. needs vitamins)
    • Bordetella (complex media with nicotinic acid)
    • Francisella (highly fastid.)

Gram -ve coccoids:

  • obligate aerobes
    • Neisseria (bean-shaped diplococci, fastid., oxidase +ve)
    • Acinetobacter
    • Moraxella (oxidase +ve)
    • Branhamella (oxidase +ve)
  • anaerobes
    • Veillonella (oxidase neg., fastid.)
  • intracellular
    • Rickettsia
    • Coxsiella
    • Chlamydia

Gram -ve Spiral/Curved:

Gram +ve rods:

  • sporing:
  • non-sporing:
    • Lactobacilli
    • Listeria
    • Erysipelothrix
  • coryneform & filamentous:
    • Corynebacterium
    • Propionibacterium
    • Actinomyces
    • Nocardia
  • mycobacteria (not really Gram +ve)
  • Streptomyces

Gram +ve cocci:

Cell wall deficient bacteria:

  • Mycoplasmataceae
    • Mycoplasma (need sterols, most fac.anaer.)
    • Acholeplasma (do not need sterols)
    • Ureaplasma (hydrolyse urea, need urea & sterols)
  • L forms of Classical bacteria (require hypertonicity)
    • NB. induced by antibiotics/lysozyme/Ab-C/osmotic/etc.
    • Need phase contrast or Giemsa stain;
    • stable L-forms (wholly cell wall defic. abn. form)
      • not able to revert;
    • unstable L forms (partly defic. cell wall abn. form)
      • revert to normal form of bacteria if inducing factor withdrawn;

Pyogenic bacteria:

  • Include:
    • pyogenic cocci - S.aureus; Str.pyogenes/pneumoniae; N.mening./gono.
    • Gram-ve rods - E.coli; Proteus; Ps.aerug.; Bacteroides;
bacteria.txt · Last modified: 2020/06/22 15:47 by gary1