Survey of Organisms in Microbiology

Taxonomy of infectious agents and parasites

Kingdoms example of organisms included

Monera bacteria

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

BacteriaGroup Example GenusGram positive bacteria

High GC MycobacteriumLow GC Bacillus

Proteobacteriaalpha Rickettsiabeta Bordetellagamma Escerichiadeltaepsilon Helicobacter

Spirochaetes BorreliaOther groups

ProtistsGroup Common name Example

Mastigophora flagellates Giardia

Apicomplexa sporozoans Plasmodium

Sarcodina amoebas Entamoeba

Ciliophora ciliates Balantidium

Deuteromycota- fungi imperfecta

Ascomycota- sac fungi

Although many are multicellular, some fungi (yeasts) are unicellular

Fungi

Flat worms (Platyhelminthes)

• Cestodes - tapeworms• Trematodes- flukes

Tapeworms (Cestodes)

Ingestion of meat

Ingestion of feces

Trematodes

feces

Ingestion of aquatic vegetation or penetration of larvae

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

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

Diseases caused by arthropods

Arthropods:Insects

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

•chigoe Tunga penetrans

InsectsSiphonaptera-fleasDiptera-fliesNematoceraCeratopogonidae-no-see-ums, sand gnatsCulicidae-mosquitoesPsychodidae-sand fliesSimuliidae-blackfliesBrachyceraTabanidae-horse and deer fliesCyclorrhaphaMuscidae-housefliesGlossinidae-tetse fliesMiscelaneous families-Botflies, blowflies, bottlefliesHemiptera-bugsReduviidae-conenose (kissing) bugsCimicidae-bed bugsDictyopteraBlattidae-roachesAnoplura-sucking lice

Myiasis

Squirrel bot fly: Cuterebra emasculator

Fly maggots can be facultative or obligate parasites, the resulting diseases are collectively called myiasis

Artrhopods: Mites (including ticks)Arachnida

AcariIxodidae-hard ticksArgasidae-soft ticksLaelapidae-hematophagous mitesDermanyssidae-hematophagous mitesDemodicidae-follicle mitesTrombiculidae-chiggersSarcoptidae-scabies mites Ticks

Ticks

Lone star tick

American dog tick

Black legged tick (deer tick)

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

Scabies mites• Sarcoptes scabiei

Other Mites

Follicle mites Demodex spp.

Chiggers Eutrombicula alfreddugesi

Viruses

Classified by nucleic acid type

Divided into Orders (sometimes), Family, Genus, ad Species

Ex. Rhabdoviridae, Lissavirus, Rabies Virus

Viral nucleic acids

dsDNA

ssDNA

dsRNA

(+)RNA

(-)RNA

RNA viruses often carry RNA polymerase or reverse transcriptase

Prions

Infectious proteins

Normally found on surface of mammalian cells

Abnormal secondary and tertiary structures

Resistant to heat and radiation

Long ‘incubation’ period

Prion “replication”

Normal protein transformed from helices to beta pleated sheets