Download overview of microbes

OVERVIEW OF
MICROBES
Taxonomy is the science of classification and the
goal of it is to group organisms into categories
based on their evolutionary relationships.
However, this is difficult because we do not always
know the evolutionary relationships of organisms
and often are methods are based on criteria that
do not accurately reflect actual relationships.
DOMAIN ARCHEA
• The Archeabacteria:
– Are prokaryotes
– differ from the eubacteria
– are the “leftovers” of the first living organisms
– generally are found in harsh environments
Some Archeabacteria
• Extreme thermophiles
– Sulfolobus
– Pyrodictium occultum
• Methanogens
– Methanobrevibacter
– Methanobacterium
DOMAIN BACTERIA
Anaerobic chemoorganotrophs
(fermenters)
Clostridia - spore formers,
Gram positive, bacilli,
strict anaerobes.
Serious diseases such
as gangrene
(Clostridium
perfringens), botulism
(C. botulinum), and
tetanus (C. tetani)
Lactic Acid - Gram positive
organisms, produce lactic acid,
catalase negative organisms.
From mouth, vagina, milk and
diary products. Medically
significant species: Listeria
monocytogenes (listeriosis) &
Erysipelothrix rhusiopathiae
(erysipeloid).
Also, Streptococcus,
Enterococcus etc. that are
microaerophiles. Medically
important species:
Streptococcus pyogenes (strep
throat, rheumatic fever etc.), S.
agalactiae (severe infections in
newborns), & S. pneumoniae
(otitis media, pneumonia, and
meningitis)
The genus,
Propionibacterium,
contains Gram +
bacilli some of which
are important in the
dairy industry
.
Anoxygenic Phototrophs,
probably the earliest
photosynthetic bacteria
Purple sulfur bacteria
are large and are
found in sulfur rich
habitats but purple
non-sulfur bacteria do
not use sulfur.
There are also green
sulfur and non-sulfur
bacteria.
Oxygenic Phototrophs
include the cyanobacteria.
There are more than 60
genera.
Some fix nitrogen,
others oxidize
hydrogen and others
are nitrifiers.
Aerobic Chemolithotrophs
include the Sulfur
oxidizing bacteria
Sulfur-oxidizing
bacteria. Bright spots
are intracellular sulfur
globules.
Photo by A.S. Engel.
Aerobic Chemoorganotrophs
Some are obligate
aerobes
Others are facultative
anaerobes
Obligate aerobes
The pseudomonads motile rods with polar
flagella. Many
produce pigments.
Many are free-living,
but some such as
Pseudomonas
aeruginosa, cause
infections esp. in
immunocompromised.
Micrococci - Gram
positive, spherically
shaped bacteria,
found on human skin,
on dust, inanimate
objects, and in soil.
Micrococcus luteus
Mycobacteria
include harmless
species and those
that are medically
important (e.g.,
Mycobacterium
tuberculosis and
M. leprae). They
typically stain
poorly with the
Gram stain
Facultative anaerobes
Staphylococci arranged in clusters,
catalase positive.
Staphylococcus
aureus (sepsis, Toxic
Shock Syndrome
etc.).
Enterobacteria – coliforms or
that are free-living, possess
peritrichous flagella. Medical
significant species:
Escherichia coli (normal flora
but also meningitis, diarrhea,
utis), Klebsiella pneumomiae
(normal flora but also
pneumonia), Proteus
mirabilis (normal flora, utis),
Serratia marcescens (normal
flora, utis), Salmonella typhi
(typhoid fever), S.
typhimurium (food
poisoning), Shigella
dysenteriae (dysentery), &
Yersinia pestis (plague).
Corynebacterium Gram + bacilli. Some
species are part of
the normal flora, while
there are some
disease causing
species e.g.,
Corynebacterium
diphtheriae.
Miscellaneous
bacteria
Spirochetes -spirally shaped
bacteria, flexible cell wall
and axial filaments.
Medically significant
spirochetes include:
Treponema pallidum
(syphilis), T. pertenue
(yaws), Leptospira
interrogans
(leptospirosis), Borrelia
recurrentis and B.
hermisii (relapsing fever),
and B. burgdorferi (Lyme
disease).
Curviform Gram - Bacteria
include many saphrophytic
species that live in aquatic
habitats and bdellovibrios
(which prey upon other
species of bacteria). Medically
significant curviform bacteria
include: Campylobacter jejuni
(bacterial gastroenteritis), and
Spirilium minus (rat bite fever).
Source: Contracted from untreated
drinking water, infected pets, and
when contaminated meat,
poultry, milk, or shellfish is eaten
raw or undercooked. Symptoms
(after eating): Onset: 2-10 days;
severe diarrhoea (possibly
bloody), cramps, fever, and
headache lasting 1-10 days.
Vibrios - curved or
straight Gram –
bacteria. Some are
luminescent. The
medically significant
vibrios include: Vibrio
cholerae and V.
parahaemolyticus.
Rickettsias – small,
generally unable to
reproduce outside of their
host’s cells. The
rickettsias are
responsible for such
diseases as Rocky
Mountain Spotted Fever
(Rickettsia rickettsia) and
Q disease (Coxiella
burnetii).
Chlamydias - lack
peptidoglycan, two
forms in their life
cycle.Medically
significant species
include Chlamydia
trachomatis (the
causative
organism of a very
common STD).
Mycoplasmas - a diverse
group of bacteria that are
grouped together because
they all lack cell walls.
Some species are free
living while others cause
disease in both plants and
animals (e.g.,
Mycoplasma pneumoniae)
DOMAIN EUKARYA
KINGDOM PROTISTA
Algae
Many of the algae have a beneficial effect
on humans and other organisms (e.g.,
photosynthesis).
Some algae do produce toxins that cause
problems in marine ecosystems (paralytic
shellfish poisoning).
Red tides can result
from large numbers of
the dinoflagellate,
Gymnodinium breve
or be caused by
Gonyaulax (more
serious).
Pfisteria piscida is a
protist that causes
high mortality in fish
and also serious skin
and neurological
problems in other
vertebrates (including
humans).
Other protists
Mastigophora posses one or
more flagella. Some
species are free living
and many are live
symbiotically with other
organisms (e.g.,
Trichonympha ).
Medically significant
flagellates include:
Trypanosoma sps.
(Chaga’s disease and
sleeping sickness), and
Giardia lamblia (Hiker’s
diarrhea).
Ciliata possess cilia.
Examples include
Paramecium (a free
living species) and
one parasite,
Balantidium coli.
Sarcodina move by
cytoplasmic
streaming which
results in amoeboid
movement. Medically
significant examples
include: Entamoeba
histolytica (Traveler’s
diarrhea) and
Naegleria fowleri
(encephalitis).
Sporozoans are nonmotile and form
spores. Examples
include: Plasmodium
sps. (malaria) and
Toxoplasma gondii
(toxoplasmosis)
KINGDOM
MYCETEAE
Many fungi are
saphrophytic and play
an important role in
nutrient cycling.
Many species cause
disease in plants
(e.g., Dutch elm
disease) and a few
species cause
disease in humans.
Some species are
single-celled
organisms (e.g.,
yeasts). Many of the
fungi that cause
disease in humans
are opportunistic
(e.g., Candida,
Cryptococcus
neoformans etc.)
a few species (four) are
true pathogens (e.g.,
Histoplasma
capsulatum).
Some species of fungi
are also involved in
allergies and others
are responsible for
various skin infections
(mycoses).
KINGDOM
ANIMALIAE
Animals
Animals that are included in microbiology or
parasitology include:
The helminth worms e.g., Ascaris
lumbricoides, Trichinella , Dracunculus
medinensis , and Wucheria bancrofti
The flukes e.g., Schistosoma (blood fluke)
and the Oriental liver fluke, Clonorchis
sinensis
The other flatworms or tapeworms (e.g.,
Taenia saginata and T. solium)
Dracunculus
Ascaris
Schistosoma
Taenia
Viruses
The stages of viral infection are:
1. Attachment to the host’s cells
2. Penetration of the host cell (injection of
the nucleic acid core)
3. Synthesis of nucleic acid and capsids
4. Assembly of new viruses
5. Lysis of the host cell with release of the
viruses
Emerging viruses include:
•
•
•
•
Ebola
Hantavirus
Marburg
SSARs virus
Prions diseases include:
• BSE, Kuru etc.
"The United States Department of Agriculture tests
approximately .03 percent of U.S. slaughtered cattle for mad cow
disease in their random spot tests
•
•
•
•
Creekstone Farms Premium Beef, LLC is a conventional and angus beef
producer and limited liability company with livestock based in Campbellsburg,
Kentucky and processing and sales in Arkansas City, Kansas. The CEO of
Creekstone, John Stewart (who is also the owner of the Triad Foods Group)
founded the company in 1995 along with his wife, Carol Stewart. Creekstone
Farms is also co-owned by Sun Capital Partners. The majority of their
distributors are not chains, but Publix does distribute their products in some
states.
Creekstone Farms is most well known for its attempt to test all of its beef for
bovine spongiform encephalopathy (BSE, or "mad cow disease"). At a cost of
about half a million dollars, Creekstone built a testing lab, the first inside a U.
S. meat packing plant, and hired the necessary personnel. In 2004, however,
the U.S. Department of Agriculture, which controls the sale of testing kits,
refused to sell Creekstone enough to test all of its cows.
The USDA's stated position was that allowing any meatpacking company to
test every cow would undermine the agency's official position that random
testing was scientifically adequate to assure safety. The USDA also claims
that testing does not ensure food safety because the disease is difficult to
detect in younger animals. An alternative position is that the USDA's objection
is the result of pressure from larger meatpacking operations. The president of
the National Cattlemen's Beef Association told the Washington Post that "If
testing is allowed at Creekstone, we think it would become the international
standard and the domestic standard, too." Creekstone Farms says tests cost
about $20 per animal, increasing the cost of beef by about 10 cents per
pound. The USDA currently tests about 1 percent of cattle slaughtered in the
U.S.
From wikipedia
End of notes for
Exam II