Survey of Organisms in Microbiology

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Survey of Organisms in Microbiology
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• Taxonomy of infectious agents and parasites

Kingdoms example of organisms included Monera bact
eria Protista protists, protozoa Fungi molds,
yeasts Animalia helminthes, arthropods Non-living
agents Viruses vary by nucleic acid type, capsid
and envelope Prions vary by tertiary
structure and AA sequence
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Bacteria

• Group Example Genus
• Gram positive bacteria
• High GC Mycobacterium
• Low GC Bacillus
• Proteobacteria
• alpha Rickettsia
• beta Bordetella
• gamma Escerichia
• delta
• epsilon Helicobacter
• Spirochaetes Borrelia
• Other groups

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Protists
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Fungi

• Deuteromycota- fungi imperfecta
• Ascomycota- sac fungi
• Although many are multicellular, some fungi
  (yeasts) are unicellular

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Flat worms (Platyhelminthes)

• Cestodes - tapeworms
• Trematodes- flukes

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Tapeworms (Cestodes)
Ingestion of feces
Ingestion of meat
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Trematodes
feces
Ingestion of aquatic vegetation or penetration of
larvae
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Nematodes (round worms)
Some representatives of major groups Hookworms
penetration Pinworms-ingestion
inhalation Whipworms and Trichinella-ingetsion of
meat Ascaris worms- ingestion of feces Guinea
worms- ingestion of water and vector Filarial
worms-insect bite
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Arthropods
Insects-flies, bugs, lice, fleas,
roaches Arachnids-ticks and mites Crustaceans-
barnacles, copepods
Note some of the above are vectors, some are
parasites, some are both
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Diseases caused by arthropods
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ArthropodsInsects

• Pediculosis- louse infestation with Pediculus
  humanis (body), P. capitis (head) or Pthirus
  pubis (crab louse)
• chigoe Tunga penetrans

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Insects

• Siphonaptera-fleas
• Diptera-flies
• Nematocera
• Ceratopogonidae-no-see-ums, sand gnats
• Culicidae-mosquitoes
• Psychodidae-sand flies
• Simuliidae-blackflies
• Brachycera
• Tabanidae-horse and deer flies
• Cyclorrhapha
• Muscidae-houseflies
• Glossinidae-tetse flies
• Miscelaneous families-Botflies, blowflies,
  bottleflies
• Hemiptera-bugs
• Reduviidae-conenose (kissing) bugs
• Cimicidae-bed bugs
• Dictyoptera
• Blattidae-roaches
• Anoplura-sucking lice

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Myiasis
Fly maggots can be facultative or obligate
parasites, the resulting diseases are
collectively called myiasis
Squirrel bot fly Cuterebra emasculator
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Artrhopods Mites (including ticks)

• Arachnida
• Acari
• Ixodidae-hard ticks
• Argasidae-soft ticks
• Laelapidae-hematophagous mites
• Dermanyssidae-hematophagous mites
• Demodicidae-follicle mites
• Trombiculidae-chiggers
• Sarcoptidae-scabies mites

Ticks
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Ticks

• Ticks are important vectors
• Some species also cause tick paralysis

American dog tick
Lone star tick
Black legged tick (deer tick)
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Scabies mites

• Sarcoptes scabiei

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Other Mites
Follicle mites Demodex spp. Chiggers
Eutrombicula alfreddugesi
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• Viruses

Classified by nucleic acid type Divided into
Orders (sometimes), Family, Genus, ad
Species Ex. Rhabdoviridae, Lissavirus, Rabies
Virus
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Viral nucleic acids
dsDNA ssDNA dsRNA ()RNA (-)RNA
RNA viruses often carry RNA polymerase or reverse
transcriptase
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Prions
Infectious proteins Normally found on surface of
mammalian cells Abnormal secondary and tertiary
structures Resistant to heat and radiation Long
incubation period
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Prion replication
Normal protein transformed from helices to beta
pleated sheets