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Atypical bacteria
Lecture 7
Question | Answer |
---|---|
Mycoplasmataceae | Mycoplasma and ureaplasmasmallest living known free organismpleomorphic shapeno cell wallresistant to penicillin and lysozymecytoplasmic membrane has sterolsattachment organelle with P1 adhesin (absence leads to avirulence)nucleoid |
Rickettsiaceae | Rickettsia and Orientiasmall, baccilli, coccoidalsimilar to gram-obligate intracellular pathogenscannot be cultured on agarno coenzyme A, NAD, or ATPzoonotic |
Anaplasmataceae and Coxiella | erlichia, anaplasma, neorickettsia, and wolbachiaobligate intracellular pathogenszoonotic |
Chlamidiaceae | Chlamydia and Chlamydophilahuman infection only: trachoma, inclusion conjunctivitis, lymphogranuloma venereumzoonotic infections: birds to mansmall, non-motile, coccoidalobligate intracellular pathogensno peptidoglycan in 1st stage of life cycle |
Chlamydia life cycle | EB taken into host for phagocytosisEB--> IB (8hrs)IB grows and divides by binary fission24-48 hrs IB reorganizes--> EBhost cell liberates EB |
Elementary body | non replicatinginfectioussmalladapted for extracellular survivalinduce endocytosismetabolically inactive |
Reticulate or Intermediate Body | replicatingnon infectiouslargeradapted for intracellular growthdoes not induce endocytosismetabolically active |
Saprobes | live on dead or decaying matterall fungi |
symbionts | association with mutual advantage |
commensals | one benefits, the other neither benefits nor is harmed |
parasites | lives on or within a host, harmful to host |
yeasts | unicellular, round/ovalreproduce by buddingpseudohyphae |
Molds | multicellularhyphae, which intertwine to form myceliumreproduce sexually or asexually by producing spores |
Hyphae | thread like branching filaments, nucleated tubes of cytoplasmpermanentdifferentiationbranchingarthrospores and chlamydospores |
septate | partitioned |
aseptate | not partitioned |
mycelium | intertwined mass of hyphaevegetative: attached to substrate/penetrates to obtain substratereproductive: aerial structures, conidiacotton wool appearance on agar |
dimorphism | same organism can exhibit 2 formsdepends on chemical and physical factorsFree liviing: mycelial or hyphal formsparasitic: yeast forms |
fungal staining procedures | KOH: take scraping from margin of lesion, add KOH , warm slide |
eukaryotic cell | cell surface, cell wall,cytoplasmic membrane, nucleus,cytoplasm, cytoskeleton, ribosomes (80S)no locomotion structure or capsule (except cryptococcus) |
cell wall | no peptidoglycan, thick and rigidchitinglucans, proteins, and maybe lipids |
cytoplasmic membrane | phospholipid bilayerergosterol, not cholesterolsite of antifungal drugs |
cytoplasmic contents | golgi body, ER, cytoskeleton, 80S ribosomes, microtubules |
eukaryotic nucleus | nuclear membrane boundmost haploidcontains chromosome |
zygomycetes | most primitivefilamentousnon-septatesexual and asexual reproductionopportunistic |
ascomycetes | septate, seexual and asexual spores |
basidiomycetes | septate, sexual sporesmushrooms and puffballs |
deuteromycetes | septatereproduce asexuallysexual reproductive structures unknown |
archiascomycetes | sexually and asexually |
fungal diseases:mycoses | systemic:inhalation, pulmonary then disseminatedsubcutaneous: wound punctures, localizedcutaneous: keratinized and cutaneous tissuesuperficialopportunistic: immunosuppressedmycotoxins: mycetismus and afloatoxin |
features shared with bacteria | microorganismsgrow axenicallyaerobic or facultativemost are not capable of invading human tissue |
features different from bacteria | eukaryoticdifferent internal organs80Sribosomelargerbiochemically differentgrow more slowlymultiple reproductive patterns |