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Blueboom/Atypical Bacteria

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Mycoplasmataceae species

Examples include:

  • Mycoplasma pneumoniae
  • Mycoplasma genitalium
  • Mycoplasma hominis
  • Ureaplasma urealyticum

Size and Shape

  • smallest known free-living organisms .15-.3 diameters
  • contain minimal set of organelles required for growth and replicaion
  • shape varies: pleomorphic (coccoid or long filaments) relates to cellular division
  • unique feature: possess no cell wall -entire life
  • do not synthesize peptidoglycan but will stain pink on gram staining
  • resistant to certain antimicrobial agents (penicillian and lysozyme)


  • cytoplasmic membrane is the external surface layer
  • typical phosphloipid bilayer structure
  • unique feature: contains sterols

  • provide integrity and strength but allows mycoplasmataceae species suseptible to amphotericin B

Cytoplasm

only contains DNA and ribosomes, has filamantous shape

Unique feature

  • attachment organelle

in M pneumonaiea M genitalium

  • allows attachment to epithelial cells lining respiratory and urogenital tract
  • has a tapered tip coated with P1 adhesin attaches to receptors at base of cilia
  • results in tissue destruction due to hyrpogen peroxide and superoxide ion
  • absense of organelle leads to avirulence

nucleoid

  • small genome
  • smallest capable of self production encodes for a few proteins requires supplemental media . single circular strand of DNA


Rickettsiaeceae

  • includes rickettsia and orientia

size and shape

  • small .3-.5 x .8-1.0 micrometers
  • shape bacilli - coccoidal (pleomorphic)
  • closely related to Gram negatives (do not stain well) use giemsa or gimenez stain

unique features

  • obligate intracellular pathogens
  • unable to produce sufficient energy to replicate extracellulary
  • can not be cultivated on agar
  • only grow in/on cell culture embyronated eggs susceptible animals
  • b/c Possess no coenzyme A, NAD or ATP - all obtained from host
  • rickettsia - grow in cytoplasm of cells
  • zoonotic- transmitted via arthropod vectors such as ticks lice fleas mites
*  eg R prowazekii human body louse, R rickettsiae - wook tick

Anaplasmataceae and coxiella

  • family anaplasmataceae
  • medically important:
  • E chaffeensis E ewingii A phagocytophilum causing Ehrlichiosis, C.burnetti causes Q fever (cattle goats sheep)

small .2-2.0micrometers

  • obligate intracellular pathogens
  • zoonotic anaplasmataceae
  • arthropd vectors : ticks


chlamydiacea

  • chlamydia:

C trachomatis

  • chlamydophila:

C psittaci, C.pneumoniae

  • human infections only: trachoma,inclusion conjunctivitis & lymphogranuloma venereum
  • zoonotic infections (birds-> man) Parrots finches pigeons chickens ducks turkeys and seabirds

size and shape

  • small .2-.7 micrometers
  • not motile
  • coccoidal

unique feature

  • obligate intracellular pathogens
  • grow in cytoplasmic vacuoles in limited host cell types depend on host for ATP and NAD+
  • can not synthesize ATP or reoxidze NADP
  • no detectable flavoproteins or cytochromes
  • No peptidglycan detected in 1st stage of life cycle
  • complex life cycle producing 2 developmental forms
  • which is detected by gimenez and giemsa stains

Elementary Body (EB) Reticulate (RB) or Initial Body (IB) Non replicating Replicating infectious non-infectious small .25-.3 micrometers larger.5-.7 micrometers diameter adapted for extracellular survival adapted for intracellular growth induce endocytosis does not induce endocytosis metabolically inactive metabolically active


developmental cycle

  1. eb taken into host by phagocytosis
  2. next 8 hours EB reorganizes -> RB (IB)
  3. RB grows and divides by binary fision
  4. 24-48 hours RB reorganizes -> EB (forms cell wall)
  5. Compled host cell liberates EB's
    • this life cycle is unique to chlamydia*

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