MICROBE MINUTES EXAM 2

E. faecalis: shape?

Cocci (spherical), form short or long chains

E. faecalis: location?

Gut (common but small part of normal gastric flora), other mammals and birds, soil, plants, water

E. faecalis: why is it found in water?

Usually due to fecal contamination

E. faecalis: pathogenic?

Opportunistic pathogen. Not usually disease causing, but can be under certain circumstances

E. faecalis: what diseases does it cause?

Endocarditis, sepsis, urinary tract infections (UTIs), meningitis

E. faecalis: Gram stain?

Gram positive (blue/purple)

E. faecalis: anaerobe or aerobe?

Facultative anaerobe (can use oxygen as terminal electron acceptor, but can also ferment)

E. faecalis: size?

Normal

E. faecalis: growth temperature?

Wide range, 10-45 C (no single optimum given)

E. faecalis: spores?

Non-spore forming (neither a Bacillus nor a Clostridium)

E. faecalis: motile?

Non-motile (no flagella or other means of locomotion)

E. faecalis: what does "coccus" mean?

Spherically shaped

E. faecalis: what does "entero" mean?

Gut dwelling

E. faecalis: what does "faecalis" mean?

Associated with feces

E. faecalis: what happened in 1899?

First described by Thiercelin, who put it in the new genus Enterococcus

E. faecalis: what happened in 1906?

Renamed Streptococcus faecalis by Andrews and Harder

E. faecalis: why was it put in Streptococcus?

It forms chains in liquid, and Streptococcus means "berries on a chain"

E. faecalis: what happened in 1984?

Molecular techniques showed it was not closely related to Streptococcus, so genus Enterococcus was revived

E. faecalis: what group is it part of?

LAB group (lactic acid bacteria)

What do all LAB group bacteria do?

Ferment lactose into lactic acid (group is very diverse, with pathogenic and non-pathogenic members)

E. faecalis: preferred metabolism?

Fermenting lactose into lactic acid

E. faecalis: what other substrates can it catabolize?

Glycerol, lactate, malate, citrate

E. faecalis: besides fermenting, how can it make ATP?

Oxidative phosphorylation under certain conditions (electron transport chain)

What does nosocomial mean?

Hospital-acquired infection

E. faecalis: why is it a major cause of nosocomial infections?

Hospital patients are sicker with weaker immune systems (allows overgrowth), and catheters and devices spread it to areas where it should not be

E. faecalis: why does it have high antibiotic resistance?

Naturally encodes plasmids, which are vehicles of horizontal gene transfer carrying resistance genes

E. faecalis: which antibiotics is it resistant to?

Beta-lactam family, also vancomycin resistance

E. faecalis: what environmental insults is it highly resistant to?

Bile salts, detergents, heavy metals, desiccation, ethanol (would kill a run-of-the-mill E. coli)

E. faecalis: salt tolerance?

Can grow at high NaCl concentrations (higher than Bacillus subtilis or E. coli)

E. faecalis: pH range?

Grows in acidic, neutral, and alkaline conditions (up to pH 9.6), which is unusual V. vulnificus: shape?;Comma shaped (curved rods)

V. vulnificus: location?

Marine and estuarine environments

V. vulnificus: what is it isolated from?

Seawater, sediments, plankton, shellfish

V. vulnificus: where is it endemic?

Southeastern United States (Gulf of Mexico, Atlantic coast, also West Coast)

V. vulnificus: how is its range changing?

Expanding due to global warming. Found as far north as Cape Cod, with recent outbreaks in Connecticut

V. vulnificus: pathogenic?

Yes. Causes vibriosis and is a notorious wound infector

V. vulnificus: Gram stain?

Gram negative (pink/red), very thin layer of peptidoglycan

V. vulnificus: anaerobe or aerobe?

Facultative anaerobe (likes oxygen as terminal electron acceptor but does not need it)

V. vulnificus: size?

Small

V. vulnificus: optimal growth temperature?

37 C (can survive slightly higher)

V. vulnificus: spores?

Non-spore forming (neither a Clostridium nor a Bacillus)

V. vulnificus: motile?

Yes. Flagella, and also twitching motility

What does twitching motility use?

Pili

V. vulnificus: what well-known microbe is it related to?

Vibrio cholerae, the causative agent of cholera

What does "Vibrio" mean?

Latin for "to vibrate" (its motion)

What does "vulnificus" mean?

Latin for "to wound"

V. vulnificus: salt requirement?

Halophile (requires salt for growth)

V. vulnificus: how is it most commonly acquired?

Eating contaminated seafood (undercooked shellfish) or through an open wound in the water

V. vulnificus: when is peak incidence?

Warm summer months

V. vulnificus: what happened in 1976?

First recognized as an agent of disease (blood culture samples sent to the CDC)

V. vulnificus: what happened in 1979?

First documented human case

Symptoms of vibriosis?

Vomiting, diarrhea, abdominal pain

V. vulnificus: who is most affected?

Immunocompromised people and people with liver disease (healthy people usually do okay)

V. vulnificus: symptoms of primary septicemia?

Fever, chills, septic shock, death

V. vulnificus: mortality rate in immunocompromised?

Over 50%

V. vulnificus: share of seafood-related deaths?

95% of all seafood-related deaths

V. vulnificus: how does it invade?

Directly from the GI tract or broken skin, producing bacteremia and septicemia

V. vulnificus: what characterizes a wound infection?

Blister-like skin lesions and rapidly spreading necrosis

V. vulnificus: why expect to hear more about it?

It is an emerging pathogen D. radiodurans: shape?;Cocci (spherical), normally forms tetrads

D. radiodurans: shape?

Cocci (spherical), normally forms tetrads

D. radiodurans: what is a tetrad?

Four cocci together, formed during division

D. radiodurans: location?

Can be found in areas with high levels of radiation

D. radiodurans: pathogenic?

Non-pathogenic (no evidence it causes disease)

D. radiodurans: Gram stain?

Gram positive (purple), but cell wall is like a Gram negative

D. radiodurans: what is unusual about its cell wall?

Has a primitive outer membrane, but not developed enough to stain pink

D. radiodurans: anaerobe or aerobe?

Aerobic (needs oxygen as terminal electron acceptor)

D. radiodurans: size?

Big, 1.5-3.5 um in diameter

D. radiodurans: optimal growth temperature?

25-35 C (mesophile)

D. radiodurans: spores?

Non-spore forming

D. radiodurans: motile?

Non-motile (no flagella, no twitching, no gliding)

What does "Deinococcus" mean?

Greek for "terrible berry"

What does "radiodurans" mean?

Latin for "radiation surviving"

D. radiodurans: original genus?

Micrococcus ("small berries")

D. radiodurans: why was it moved to its own genus?

Ribosomal RNA sequences showed it was not closely related to other Micrococcus species

D. radiodurans: who discovered it, when, and where?

Arthur Anderson, 1956, Oregon Agricultural Experiment Station (Corvallis, Oregon)

D. radiodurans: what was being studied when it was found?

Whether canned food could be sterilized with high doses of gamma radiation

D. radiodurans: how was it found?

A tin of meat given a dose thought to kill all known life still spoiled

D. radiodurans: what record does it hold?

Guinness Book of World Records "world's toughest bacterium"

D. radiodurans: how is its resistance different from spore formers?

It resists radiation in its metabolically active form. Even Clostridium and Bacillus spores cannot withstand gamma/ionizing radiation

D. radiodurans: what is it extraordinarily resistant to?

Radiation and desiccation (drying out)

D. radiodurans: how much radiation can it survive?

3-5 million rad (100 rad is lethal to humans)

D. radiodurans: what application is it studied for?

Bioremediation (cleaning up nuclear accident sites, nuclear waste, and associated chemicals)

D. radiodurans: genome structure?

2 circular chromosomes and 2 plasmids

D. radiodurans: how does it repair DNA damage?

Multiple copies of each gene on all chromosomes and plasmids, so an undamaged copy is the template to fix the damaged one

How does a typical bacterial genome differ from D. radiodurans?

Most have one circular chromosome with only one copy of each gene

D. radiodurans: role of manganese?

High intracellular manganese acts as an antioxidant, protecting (repair) proteins from damage

D. radiodurans: how fast does it repair its genome?

Within 12-24 hours of radiation exposure T. pallidum: shape?;Spiral shaped (spirochete), very thin and narrow

T. pallidum: shape?

Spiral shaped (spirochete), very thin and narrow

T. pallidum: location?

Obligate intracellular (must live within host cells), humans only

T. pallidum: what cells does it infect?

Epithelial cells

T. pallidum: pathogenic?

Yes. Causative agent of syphilis

T. pallidum: Gram stain?

Gram negative (pink/red)

T. pallidum: Gram negative features it keeps?

Thick periplasmic space and very thin layer of peptidoglycan

T. pallidum: how does it differ from a typical Gram negative?

Outer membrane does not contain lipopolysaccharide (LPS)

T. pallidum: anaerobe or aerobe?

Strict anaerobe

T. pallidum: why is it killed by oxygen?

Catalase and oxidase negative, so no protection from reactive oxygen species

T. pallidum: size?

Very narrow, 0.1-0.2 um in diameter but 6-15 um long

T. pallidum: optimal growth temperature?

37 C (mesophile, human pathogen)

T. pallidum: spores?

Non-spore forming (neither Clostridium nor Bacillus)

T. pallidum: motile?

Yes, with internal flagella

T. pallidum: where are the flagella?

In the periplasmic space, wrapped around the cell. They do not protrude from the surface