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what are the general characteristics of Enterobacteriaceae?
- 1.Facultative (aka optional) anaerobic, gram negative rods
- 2. Motile by peritrichrous flagella
- 3. Inhabit intestinal tracts of humans, poultry etc
- 4. Pili (appendage used for conjugation & gliding motility)
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Gram Negative Rods: Enteric Bacteria
What bacteria is the most common in human intestines?
Escherichia coli
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Gram Negative Rods: Enteric Bacteria
List characteristics of Escherichia coli
- 1. GRAM NEGATIVE; RODS
- 2. produces biocins & Vit K
- 3. common in human intestines
- 4. not usually pathogenic (except certain strains)
- - Can cause:
- a) UTIs
- b) "traveler's diarrhea" from produced endotoxin
- c) Strain 0157:H7, most famous! Causes severe bloody diarrhea, can be fatal, contracted from tainted meat
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Gram Negative Rods: Enteric Bacteria
List characteristics of Salmonella
- GRAM NEGATIVE; RODS
- 1. common inhabitant of poultry & cattle intestines; pathogenic to humans
- 2. can contaminate food, leads to enteritis if humans eat it.
- 3. Salmonella typhi = typhoid fever
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Gram Negative Rods: Enteric Bacteria
List characteristics of Shigella
- GRAM NEGATIVE; RODS
- 1. common inhabitant of poultry & cattle intestines; pathogenic to humans
- 2. variety of stains, can cause:
- bacillary dysentery, aka Shigellosis or sometimes "travelers diarrhea"
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
A SOIL dwelling bacterium; many strains involved in nitrogen fixation
Klebsiella
this bacteria is Gram NEGATIVE; RODS
also, k. pneumoniae causes pneumonia in humans
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
Produces the Black Plague; carried by rats and ground squirrels; transmitted to humans by a rat flea bite
Y. pesti
Yersinia --- Gram NEG; RODS
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
inhabits mucous membranes (attaches by pili adhesion and causes infection)
mucous membranes like: URT, mouth, vagina, and intestines
Haemophilus
H. influenzae- common cause of ear infections & meningitis
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
found in aquatic environments, esp stagnant water of a.c. systems
Legionalla
bacteria reside in a protozoa & can be found in water droplets which if inhaled = "Legionnaire's Disease" a fatal respiratory infection
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
-anerobic with prominent polar flagella
-can use complex molecues eg fats & carbs as a nutritional source, therefore common cause of FOOD SPOILAGE (even refrigerated)
-secretes enzyme that breaks down proteins
-causes UTIs, burn/wound infection, & meninigitis
- Pseudomonas
- GRAM NEG; RODS
-ability to digest complex substances allows them to survive even on soap
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
cause of Whooping Cough (fits of violent coughing b/c of OVERPRODUCTION OF MUCOUS that results from the bacterial toxin (pertussin)
GRAM NEG; RODS
-the pertussin (bacterial toxin) interfers with normal reg. of fluid production, thus causing OVERPRODUCTION OF MUCOUS
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Gram Negative Rods: NON-Enteric Bacteria
Name this bacteria:
anerobic capable of degrading complex organic substances for nutrition (>100 different organic molecules!)
-common infection in CYSTIC FIBROSIS
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Gram Negative Rods: Obligate Intracellular parasites (reproduce only within a mammalian cell)
Name this Group:
very pathogenic that MUST infect specific animals, usually transmitted by bites of insects and ticks
Richettsia
GRAM NEG; RODS
-
Type of Richettsia that causes Rocky Mountain Spotted Fever? (infects RBCs)
- R. richettsii
- GRAM NEG; RODS
- since it infects RBCs, causes cells to lyse & capillary damage- appears as red spots on skin
- carried by animal like deer; transmitted via tick bites
-
Type of Richettsia that causes typhus? (carried by lice)
- R. prowazeckii
- GRAM NEG; RODS
Transmitted/Carried by Lice
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Gram Negative Rods: Obligate Intracellular parasites (reproduce only within a mammalian cell)
What type of bacteria is similar to Richettsia, but instead of infecting RBCs, this bacteria infects WBCs?
causative bacteria= E. chaffeensis
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Gram Negative Curved Rods
Name the bacteria:
curved rods w. multiple flagella; found as cause of peptic ulcers & stomach cancer
can survive in acidic environment in the stomach (from HCL & other gastric juices) b/c it produces LRG quantities of enzyme urease (an ammonia like substance, aka a "strong base")
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Gram Negative Curved Rods
Name the bacteria:
found in contaminated water & nearby soil. can cause CHOLERA
- Vibrio
- (V. Cholerae is what causes cholera)
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Gram Negative Cocci
Name the bacteria group:
anerobic, DIPLOCOCCI that have pili, thus allows them to adhere to mucosal cells & cause infection
- Neisseriae
- GRAM NEG; Cocci
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Gram Negative Cocci
Name this bacteria from Neisseriae group:
cause of meningitis, infects respiratory system
Dx from CSF sample
N. meningitidiss
disease is fatal if not dxed within 48 hours. vaccine availabe, but many groups & strains exist.
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Gram Negative Cocci
Name this bacteria from Neisseriae group:
a STD, prominent pili that adheres to mucosal cells of genito/urinary systems
N. gonnorahae
many strains exist, infections occur thru human contact only. Fatal if not txed, will spread systematically, can cause sterility. no vaccine
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Gram Positive Rods
Name this bacteria:
-normally encapsulated, hard to kill
-produces endospores that are extremely resistant to environmental factors
-one type causes anthrax
B. anthracis- causes anthrax, commonly found in soil in barnyard areas
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Gram Positive Rods
Name the genus of bacteria:
-highly pathogenic, produces lethal exotoxins
-obligate (by necessity) anaerobic organisms
-produce endospores (that usually distend their cell)
-mostly soil dwelling
- Clostridium
- GRAM POS; RODS
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Gram Positive Rods
Name the species of Clostridium:
-causes tetanus (secretes an exotoxin that interferes w. normal neural transmission & induces muscle spasms)
-gain access via infected wound
can lead to death if diaphram muscles are affected (thus patient can no longer breathe)
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Gram Positive Rods
Name the species of Clostridium:
-causes severe & often incurable diarrhea
-can effect elderly esp as a nosocomial (orginating in a hospital) infection.
- C. difficile
- GRAM POS; RODS
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Gram Positive Rods
Name the species of Clostridium:
-causes "gas gangrene"
-open sores/wounds that are not washed are breeding grounds
-secretes exotoxin that destroys muscle, tissues, & even RBCs. Spreads rapidly
-Tx is amputation & antibiotics, but often fatal
- C. perfingens
- GRAM POS; RODS
a common battlefield infection
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Gram Positive Rods
Name the species of Clostridium:
-cause of botulism
-food borne disease that results from contamination of processed foods with the spores of said bacteria
- C. botulinium
- GRAM POS; RODS
- dented cans
- botox
- found in honey
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Gram Positive Rods
Name the bacteria:
-"club-shaped"
-one species is cause of diphtheria
- Corynebacterium
- GRAM POS; RODS
C. diphtheriae is cause of diphtheria (fatal, starts with severe throat infection), produces lethal toxin, vaccination available
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Gram Positive Cocci
Name the genus group:
-spherical, arranged in CHAINS
-largest group, greatest variety of infectious illnesses compared to any other group
-produce extracellular substances contributing to pathogenicity
-can destroy phagocytic cells & connective tissue
- Streptococci
- GRAM POS; COCCI
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Gram Positive Cocci
Name the species of Streptococci:
-cause scarlet fever, impetigo, pharyngitis, rheumatic fever, meningitis
S. pyogenes
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Gram Positive Cocci
Name the species of Streptococci:
-cause of pneumonia
S. pneumoniae
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Gram Positive Cocci
Name the species of Streptococci:
-cause of dental caries
S. mutans
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Gram Positive Cocci
Name the species of Streptococci:
-cause of "flesh eating"
S. fasciitis
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Gram Positive Cocci
Name the species of Streptococci:
-infection of heart valves, destruction of heart tissue
S. endocarditis
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Due to large variety of Streptococci, a useful way to classify them, is by what method?
the appearance when cultured on a blood agar plate
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What are the three categories streptococci could fall into (when cultured on blood agar plate)?
- Alpha-haemolytic
- Beta-haemolytic
- Gamma-Haemolysis
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What color do Alpha-haemolytic bacteria produce on blood agar plate?
converts hemoglobin from red to GREEN
-
What color do Beta-haemolytic bacteria produce on blood agar plate?
forms a CLEAR zone. the bacteria produce a haemolysin that lyses RBCs, thus making a clear area
-
What color do Gamma-haemolysis bacteria produce on blood agar plate?
NO CHANGE; non-pathogenic
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Gram Positive Cocci
Name the genus of bacteria:
-spherical, arranged in grapelike clusters
-grow well under high osmotic pressure & low moisture (hence enjoying nasal secretions, skin)
-certain strains cause condition called "scalded skin syndrome"
-many strains have developed antibiotic resistance
- StaphylococciGRAM POS; COCCI
some strains are designated "flesh eating" bacteria (meaning they secrete enzymes that break down connective tissue)
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Gram Positive Cocci
Name the species of Staphylococci:
-yellow pigmented colonies
-grows well in high salt & can ferment sugar mannitol
-produces toxin that invades & damages tissue (nosocomial issue, esp post-surgery)
-the toxin can lead to "toxic shock syndrome"
-freq. source of food poisoning b/c it can grow on complex substances, eg lipids
TSS- potentially fatal, occurs when infected wounds (bed sores, or surgical dressings) are not frequently changed
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Gram Positive Cocci
Name the species of Staphylococci:
-able to grow at higher osmotic pressure
-common found on skin
- S. epidermidis
- GRAM POS; COCCI
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Spirochetes
[coiled morphology w. endofilaments for motility]
Name the genus best know in the Spirochetes category:
*hint* Syphilis
- Treponema
- T. palladium causes Syphilis
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Spirochetes
[coiled morphology w. endofilaments for motility]
Name the genus in Spirochetes that contains species causing Lymes Disease
Borrelia
coiled, Lymes contracted via tick bite, highest amt of cases are in late summer, early fall
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Cell Wall-less bacteria
Name the bacteris:
-the smallest
-"fried egg appearance"
-can produce filaments that resemble fungus
Mycoplasma
easily changes shape (aka pleomorphic) b/c no cell wall
species- M. pneumoniae causes a pneumonia that is difficult to treat & may last a few weeks
-
Name the group that has:
-a fungus like appearance by microscopy
-occasionally exhibits filamentous growth
-DISTINCTIVE Cell walls that contain BOTH LPS & a waxy, water resistant substance (mycolic acid), it's essential in protection from environmental factors
- Mycobacteriumsimilar to gram neg. in structure, yet has the waxy outter coating
-cell wall enhances pathogenicity & makes it somewhat resistant to antibiotics
-
Name the Mycobacterium that:
-results in leprosy (secretes substance that breaks down cartilage, no known cure but drugs available to slow down progression)
M. leprae
*often will start in nose & ear cartilage
-
Name the Mycobacterium that:
-causes chronic & long-lasting respiratory infection. (TB) used to be called consumption
M. tuberculinium (or according to book and everyone one else, M. tuberculosis)
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Environmental Bacteria:
soil bacteria, grows near ROOTS, esp GRASSES
has a role in nitrogen fixation
Azospirillum
-
Environmental Bacteria:
soil bacteria, grows near roots of LEGUMES
Rhizobium
-
Environmental Bacteria:
aquatic bacteria
prominent extending structures called PROSTHECAE, used for getting nutrients
Cell division by BUDDING (not binary fission, making it unusual)
Caulobacter
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Environmental Bacteria:
Gram neg rods, used in SEWAGE TREATMENT
Zooglea
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What is a virus?
Consist of nucleic acid (DNA= ds or ss; RNA) with a protein coat. Must infect a living (host) cell in order to survive. Can not replicate on its own.
-
What is the coat of a virus called? What is this coat consist of?
- Capsid-- made of protein
- Capsid is made of capsomeres
-
What sometimes covers the capsid of a virus? What sometimes covers this
-
Outside of the cell, viruses are called?
Virions. They are inactive until they can infect a host.
-
What is "host range"?
The spectrum of host cells a particular virus is able to infecto
-
What are viruses that infect bacteria called? Do they infect in a certain orientation?
Bacteriophage, or phages. Infect a certain way, tailn attaches to membrane, then nucleic acid injects into cytoplasm
-
Two ways viruses replicate
Lytic cycle (ends w. Lysis n death of host cell)
Lysogrnic cycle (host cells remains alive)
-
List 5 steps to replication of T4 bacteriophage (an example of a lytic cycle)
- 1. Attachment
- 2. Penetration
- 3. Biosynthesis
- 4. Maturation
- 5. Release (cell lyses)
-
What are the steps to lysogeny pathway?
- Once phage injects nucleic acid, two options can occur. It may follow the lytic cycle OR
- 1. Nucleic material fuses w. Bacteria's chromosome by recombination becoming a Prophage
- 2. Replication of this new Dna, aka the prophage, occurs. The prophage remains latent
- 3. SOME times a spontaneous event (eg certain chemicals or UV light) can lead to excision of phage DNA which then initiates a lytic cycle.
-
What are three methods of culturing a virus?
- 1. Fertilized chick embryos
- 2. in vitro culture conditions - tissue culture
- Aka cell lines, continuous cell lines
- 3. Animal models
-
What are two ways that viruses infect eukaryotic cells?
1. Endocytosis- virus engages host membrane which "involutes" & the virus is taken up into host's cytoplasm where Capsid dissipates and nucleic acid is released
2. Fusion- envelope of virus adheres to host me!branw and the envelope re!sins at the surface.
-
Once virus enters eukaryotic cell, what three things occur?
- 1. Viral nucleic acid is transcribed, new virus is synthesized n ruptures host as it releases, host dies
- 2. As above, but new virus will LEAK from host, no host cell death
- 3. Latent infection. Virus remains dormant until some event etriggers it to start full blown infection phase.
-
What class of virus is the common cold?
Adenoviridae
-
what class of virus is an infection with pus filled lesions? eg smallpox, cowpox
Poxviridae
-
what class of virus is HHV-1, varicella, herpes simplex, zoster, chicken pox?
Herpesviridae
-
what class of virus is papillomas- warts, polyoma- tumors, association with cervical cancer?
Papovaviridae
-
what class of virus is liver disease?
Hepadnaviridae
-
what class of virus infects vertebraes? it is an RNA containing virus that converts RNA to DNA with reverse transcriptase enzyme following infection of host cell. Eg HIV, AIDS
Retroviridae
-
what is the shape of a virus?
Polyhedral
-
do viruses have organelles?
No
-
what is uncoating of a virus?
the separation of the viral nucleic acid from its protein coat once the virion is enclosed within within the vesicle. (the capsid is digested)
-
What is specialized transduction?
- A possible outcome of lysogeny pathway.
- It is when a prophage is excised from host, it can take with it a bit of adjacent DNA from host chromosome (instead of just the viral DNA becoming excised)
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