Microbio Week 3 (Exam 1) Flashcards
Which bacterial infections have NO vaccines?
Mycobacterium tuberculosis
Corneybacterium diptheria
Staph aureus
Strep pneumoniae
Strep pyogenes
Staph aureus
Strep pyogenes
T/F: Teichoic acid is found in Gram + bacteria and is sometimes inflammatory, but sometimes good
True
What bacteria?
Related to bifidobacteria, found in probiotics
found in oral, vaginal, and GI tracts; gets energy from fermentation by converting glucose -> lactic acids
Normal flora
Lactobacillus
What bacteria?
+spores, anaerobic, +/-toxins (tetanus, botulism), found in soil and gut
Normal flora
Clostridia
What bacteria?
Grows in the fridge at 40 degrees, packaged meats
Not normal flora
Listeria
What bacteria?
Common oral pathogen responsible for face and neck granular abscesses
Normal flora
Actinomyces
What bacteria?
Related propionobacteria, “diptheroids”
Normal flora
Corynebacteria
What bacteria?
Includes TB and leprosy
Not normal flora
Mycobacteria
What bacteria?
+spores, aerobic, B. anthracis
Not normal flora
Bacilli
Staphylococcus tests positive/negative for catalase, whereas Streptococcus tests positive/negative for catalase
Staph = catalase positive
Strep = catalase negative
Lactobacilli and bifidobacterium are also called _________ ________
lactic acids
What bacteria is used in food production like yogurt, cheese, and milk?
Lactobacilli
“Teichoic acids interfere with enteric pathogens and can inhibit cariogenic enzymes in Strep” is a unique feature of _______________
Lactobacillus
The first bacteria to colonize newborns and are dominate for the first 3 years
Bifidobacterium
Bifidobacterium require ________ oliigosaccharides
plant/milk
Name 2 Gram + rod spore formers
Clostridium (anaerobic)
Bacillus (aerobic or facultative)
When are endospores formed?
When bacteria run out of nutrients, during stationary growth
Uniques aspects of endospores
Heat resistant
Resistant to drying, chemicals, radiation
Viable for thousands of years
Position in cell sometimes distinctive
How to kill endospores
Autoclave
Bleach
Which bacteria are found widely distributed in soil, particularly spores?
Clostridium
These bacteria are one of the most common causes of food poisoning and gas gangrene
Clostridium perfringes
Name 2 neurotoxic Clostridium bacteria
C. botulinum (causes botulism)
C. tetani (causes tetanus)
This bacteria causes cellulitis, gas gangrene, and food poisoning
Clostridium perfringes
This bacteria causes pseudomembranous colitis
Clostridium difficile
What antibiotic is used to treat Clostridium difficile?
Vancamycin
What bacteria are small Gram + coccobacilli that are commonly found living in soil-plant environments, but can grow INSIDE host cells (intracellular)
Listeria
What is the only species of Listeria?
L. monocytogenes
This bacteria can be transmitted from commercial foods
Listeria
Listeria is a __________ ____________ that can grow in vacuum packed foods and it likes colder temperatures
facultative anaerobe
If these pts get listeria, then it’s dangerous b/c it can be transplacental or congenital (transmits from mother to fetus)
Pregnant pts
T/F: Actinomyces is acid fast
FALSE; mycobacteria is acid fast
Actinomyces is facultative, but it is only seen in ___________ sites
anaerobic
Where do we find actinomyces?
Normally in gingival crevice + gut
Also in oral + facial swellings
Which bacteria is described as Gram +, filamentous, and branching bacilli
Actinomyces
Pt presents with a cervicafacial lesion and has had non-tender swellings which drain pus through sinus tracts along the jaw and neck.
They recently had dental work done.
Which bacteria most likely caused this infection?
Actinomyces!!! most relevant to dentistry
Which bacteria is often misdiagnosed as a tumor or mass?
Actinomyces
Actinomyces cause cervicofacial lesions that are mixed ____________ infections
anaerobe
T/F: Actinomyces is only present when there’s an infection in the oral cavity.
False!! it’s also present in normal flora in the mouth, intestines, and vagina
If yellow sulfur granules are present in pus, what does the pt have?
Actinomycosis
How do you diagnose an actinomycosis infection?
Gram + stain
Seeing sulfur granules
How do you treat an actinomycosis infection?
Beta-lactam antibiotic
Surgery to biopsy, remove masses
Which bacteria?
Gram + rods found in upper respiratory tract and skin, called “diptheroids” because they look like pallisading rod or Chinese letter; not harmful
Corynebacteria (diptheroids)
Characteristics of Corynebacterium diptheriae
Irregular/club shape Gram + rods
Aerobes that do NOT form spores
Causes diptheria
This bacteria produces a soluble toxin, encoded by a lysogenic bacteriophage, which causes a membrane-like coating in the throat by ribosylation of the ribosome (can be fatal in 20% of children)
Corynebacterium diptheriae
What do the letters in the “DPT” vaccine stand for?
D = diptheria
P = pertussis
T = tetanus
What bacteria?
Gram + rods, aerobes, form spores
Bacillus
2 medically important Bacillus
Bacillus anthracis (causes anthrax)
Bacillus cereus (causes food posioning)
Is Bacillus anthracis intracellular or extracellular?
Intracellular
How is Bacillus anthracis transmitted?
Animals -> humans
What bacteria?
Gram + irregular thin rods; acid-fast staining
Mycobacteria
T/F Mycobacteria have lots of flagella and spores
FALSE; no flagella or spores
Mycobacteria have mycolic acids so we use a unique stain called “acid-fast” staining. Describe this stain
The red-stained cell wall remains stained when decolorized with acid-alcohol
All the damage of this pathogen is delayed type hypersensitivity (it doesn’t have any exoenzymes, LPS, or toxins!)
Mycobacterium tuberculosis
Mycobacterium tuberculosis has a unique capacity for _________ metabolism
lipid
Mycobacterium tuberculosis is an __________ pathogen and has no ____________ reservoir
intracellular; enviornmental
T/F: You must spend a lot of time with someone who has active TB in order to get it
True, only the tiniest particle of TB is what infects the alveoli in the lung
The 3 intracellular Gram + bacteria
1) M. tuberculosis
2) B. anthracis
3) L. monocytogenes
Which of these are Gram + spore forming rods?
Corneybacterium diptheria
Bacillus anthracis
Clostridium perfringes
Listeria monocytogenes
Bacillus anthracis
Clostridium perfringes
Enterobacteriaceae like E.coli are a large and diverse group of Gram _____ rods
Gram -
Where are enterobacteriaceae found?
Intestines of humans and animals
also in plants, soil, and water
Major enteric pathogens
Escherichia
Shigella
Salmonella
Vibrio (cholera)
What are E. coli and relatives also called?
Gamma proteobacteria or just proteobacteria
What type of infections does E. coli cause?
Intestinal
Urinary
Wound
Bloodstream
Meningeal
Antigenic typing HOK stands for…
H = flagella
O = O antigen coming off LPS in Gram -
K = Capsule
Which bacteria is the leading cause of both community-acquired and hospital infections?
E. coli
Which bacteria is the most commonly encountered member of this family in the normal intestinal flora?
E. coli
Name some diseases caused by normal flora strains of E. coli (these escape intestinal tract and colonize other body sites)
Are these endogenous or exogenous?
UTIs
Septicemia
Neonatal meningitis
They’re endogenous
Name some diseases caused by “new” strains of E. coli that have acquired additional virulence factors such as enterotoxins, fimbriae, and invasive factors
Gastroenteritis (diarrhea)
What are intestinal infections due to?
- Fecal-oral spread
- Unique strains w/ additional virulence factors
Normal flora in intestinal tract of humans can cause disease with ________ or _________ _________
trauma; immune supression
Additional virulence factors associated w/ intestinal infections
Plasmids or phage
E. coli virulence factors
LPS
Enterotoxins (LT and ST)
What are the 2 enterotoxins that are virulence factors for E. coli?
Heat-labile toxin (LT)
Heat-stable toxin (ST)
What does the heat-labile toxin (LT) in E. coli activate?
Adenylate cyclase -> fluid secretion/diarrhea
Which enterotoxin of E. coli has an identical mechanism and structure as cholera toxin?
Heat-labile toxin (LT)
What is the heat-stable toxin (ST) in E. coli responsible for?
Fluid secretion/diarrhea
(heat-labile toxin does the same thing)
E. coli can colonize and cause inflammation in the __________ and ascend to the ___________ in UTIs
bladder; kidney
Path of E. coli in invasive neonatal meningitis
intestines -> blood -> meninges
Vaginal normal flora _________ colonize the infant at birth during passage through the birth canal
E. coli
Which virulence factor is expressed by E. coli in neonatal meningitis?
Capsule (inhibits phagocytosis)
Which disease occurs when E. coli cross the epithelial surface and invade bloodstream of pts w/ immune impairment?
Bacteremia/septic shock
Large amounts of ___________ from E. coli stimulate systemic inflammation and ________ __________
endotoxin; septic shock
Most common Gram (-) rod found with sepsis
E. coli
What is a relative of E. coli (on exam)?
Klebsiella
This bacteria is similar to E. coli with virulence plasmid that allows cell invasion and intracellular growth
Shigella
T/F Shigella is closely related to E. coli and is considered part of normal flora
FALSE; Shigella is NOT part of normal flora
Which severe disease is caused by Shigella dysenteriae?
Bacterial dysentery (bloody diarrhea)
Which mild disease is caused by Shigella?
Shigellosis (diarrhea w/o blood)
What is the virulence factor for Shigella?
Intracellular growth via plasmid
What does the Shigella virulence plasmid encode proteins for?
Attachment/entry into intestinal epithelial cells
The Shiga toxin is lethal because it inhibits ________ synthesis
protein
The Shiga toxin can be transferred to _________
E. coli
The Shiga toxin can damage endothelial cells and be local or systemic. What’s the difference?
Local: bloody diarrhea
Systemic: kidney failure
Which disease is caused by colonization of large intestines with invasion/replication within colonic epithelial cells, causing erosion of large intestine?
Bacterial dysentery (S. dysenteriae)
T/F: Salmonella is NOT normal, it’s only found when disease is present.
True
2 diseases caused by Salmonella
Food poisoning
Typhoid fever
Reservoir of salmonella
Intestinal tract of birds, cattle, reptile
How are humans infected with salmonella?
Contaminated food or water (feces from infected animals)
What is the most common Salmonella infection in the US? What bacteria causes this?
Gastroenteridis (food poisoning diarrhea) - caused by S. typhimurium
What bacteria causes Typhoid fever?
S. typhi
Salmonella typhimurium has _________ survival and growth
intraceullar
What is the target cell of Salmonella typhimurium?
Macrophages
Salmonella typhimurium remains in the ____________ epithelium only
intestinal
Salmonella typhi also has ___________ growth
intracellular
What allows Salmonella typhi to invade the bloodstream and cause sepsis-like disease?
Vi capsule
There are 2 vaccines available for Typhoid fever. When should one get a typhoid vaccine?
When traveling to an underdeveloped country
Describe the appearance of Vibrio cholera
Curved, Gram - rods
Single polar flagella
Where is Vibrio commonly found?
Surface waters worldwide (it grows over wide temp ranges)
Vibrio prefer a _____ pH and are killed at a ______ pH
high; low
The cholera enterotoxin stimulates __________ secretion by chemically modifying _________ ___________
fluid; adenyl cyclase
Main virulence factor of cholera
Cholera enterotoxin (an enzyme)
What type of habitat do Vibrio like? What food are they found in?
Warm water with fecal pollution
Found in shellfish, such as oysters
Pathology of cholera
dehydration and electrolyte imbalance
How do we treat cholera?
Fluid replacement + oral rehydration
The only cholera vaccine
Vaxchora - live
(has toxin lacking A subunit - enzyme)
Which of these Gram positive rods form spores?
Listeria
Bacillus
Corynebacterium
Clostridium
Mycobacterium
Lactobacillus
Bacillus
Clostridium
Which of these is a strict anaerobe?
Clostridium
Bacillus
Corynebacterium
Listeria
Clostridium
T/F: Teichoic acids are always inflammatory
False, it may also help regulate immune responses
Which of these are intracellular bacteria?
Bacillus anthracis
Listeria monocytogenes
Clostridium perfringes
Lactobacillus acidophilus
Mycobacterium tuberculosis
Bacillus anthracis
Listeria monocytogenes
Mycobacterium tuberculosis
What is the difference between the ‘O antigen’ and Lipid A in Gram negative LPS?
A. Neisseria LPS lacks the O-antigen
B. The O antigen is used in strain typing differences among the same species
C. Haemophillus lacks the O antigen
All are true
Which of these is NOT a Bordetella toxin?
pertussis toxin (PT)
adenylate cyclase toxin
tracheal toxin
Spe superantigen
Spe superantigen
Which of these bacteria is NOT a major cause of meningitis?
Staph aureus
Strep pneumoniae
Neisseria meningitidis
Staph aureus
Which of these are true about Haemophilus influenza?
A. It is a major cause of ear infections from the throat
B. The vaccine is a protein conjugated capsule antigen
C. Can cause pneumonia
All are true
Is there a vaccine for Cholera?
Yes, it’s a live strain of Vibrio
What is the Vi capsule that is important in Typhoid Fever?
A. capsule seen only on S. Typhi bacteria
B. important in using live Salmonella as a vaccine
C. it is antiphagocytic
All are true
Which is NOT a toxin E. coli can acquire by horizontal gene exchange and become dangerous?
Shiga toxin
Heat stable toxin
Heat lable toxin
LPS endotoxin
All are E. coli toxins
What is distinct about Shigella among the other Enterobacteriaceae?
It is intracellular, invading epithelial cells
Streptocccus pneumoniae is a potentially dangerous bacteria that normally resides in the…
upper respiratory tract (mouth, nose , throat, etc).
Which of these is NOT a normal resident of the oral microbiota?
Staph aureus
Treptonema denticola
Fusobacterium nucleatum
Poryphormonas gingivalis
Staph aureus
(it’s found in the nose)
Moraxella are an odd coccus shaped Gram negative bacteria. What other genus of Gram negative coccus normally inhabits in the same body site?
Neisseria
T/F Most or all abundant oral bacteria have been proposed to play a role in periodontal disease
True
Which of this is NOT a valid theory about how periodontal disease occurs?
A. aerobic bacteria outgrow and dominate the gingival crevice
B. plaque of any kind is a contributor
C. Red Complex bacteria have a central role in disease
D. host factors and bacterial factors are both involved, adding complexity
E. Porphyromonas gingivalis is not abundant, but important in disease
A. aerobic bacteria outgrow and dominate the gingival crevice
What Gram positive bacteria are important colonizers of the gingival pocket in both health and disease?
Treptonema
Streptococcus
Actinomyces
Prevotella
Streptococcus
Actinomyces
About how many bacterial types do we now think are normally found in the mouth?
~600
T/F Periodontitis is different than other diseases that are now being associated with the gut microbiota, as studies are finding more diversity of species in disease than in health.
True
Which Mutans streptococcus contributes to caries by producing water insoluble glycans and acid?
Strep oralis
Strep sobrinus
Strep salivarius
Strep gordonii
Strep sobrinus
Which of these is a proven contributor to dental caries?
Saliva flow rates
Local pH
Strep mutans
Sucrose
Enamel composition
All are true
Which of these is NOT a known way to reduce caries?
Fluoride
Reduce frequency of sucrose intake
Probiotics
Plaque removal
Probiotics
Diseases caused by bacterial biofilm
gingivitis and periodontitis
One of the most prevalent infection-driven, inflammatory diseases
Periodontitis
How do we determine “who is there?”
16s rRNA sequence
What are the 3 red complex pathogens that initiate periodontitis?
1) P. gingivalis
2) T. forsyhthia
3) T denticola
Periodontal disease is a Microbial-shift disease. What does this mean?
it can go from homeostasis -> dysbiosis
A model of polymicrobial synergy and dysbiosis initiated by _____________ and the ensuing inflammation is exacerbated by the overgrowth of inflammophilic pathobionts
P. gingivalis
Which bacteria is highly proteolytic with gingipains being the major virulence factors?
Poryphyromonas gingivalis
Proteolytic enzymes that aid in destruction of host antibodies and localized tissue destruction
Gingipans
Virulence factor associated with periodontal bone loss
Gingipans
What do vaccines & treatments for periodontitis target?
Gingipans
Number of papers published related to “dental plaque” vs “biofilm”
Many more papers about biofilm
Why are there so many bacteria in dental waterlines?
1) surface colonization
2) laminar flow
3) surface: volume ratio (diameter decreases -> larger surface area for colonization)
Are all dental units contaminated?
Yes, but to a different degree
Different bacterias are seen at the _________ level
genus
Most common phylum present
proteobacteria
Is there any proven health risk from contaminated waterlines?
healthy ppl - not really
immunocompromised - yes
Most prevalent respiratory pathogen in contaminated waterlines
Legionella pneumophila
Ways to improve and maintain quality of water used on dental treatment
flush waterlines
independent reservoirs
chemical treatment
water source
filtration
Bacteria form biofilms in very high/low shear environments
High
Once a biofilm has formed, it behaves in a _____________ manner
rubbery
Adherent biofilm-forming bacteria get encapsulated in a ___________ ___________
Extracellular matrix
Periodontitis is caused by what bacteria?
Gram - anaerobes
Cells that fight bacteria
Phagocytes
Describe the stages of bacterial growth
1 and 2 : mutualism and commensal bacterial growth
3: transition bacterial growth
4: pathogenic bacterial growth
Strep mutant can produce large quantities of _________ _____________ ___________ and ________ that give the bacteria an advantage to outcompete noncariogenic species in low pH environment
water-insoluble glucans; acid
To cause disease, what 4 basic requirements does the pathogen need
1) adhere to tissue
2) invade host and replicate
3) acquire nutrients and avoid host immune system
4) damage host
S. mutans uses 2 methods of attachment. What are they?
1) sucrose independent
2) sucrose dependent
T/F: Sucrose independent binding occurs via ionic and lectin-like interactions.
True
Streptococcal protein antigen (SpaP)
Sucrose independent protein
_______ production is the main reason for enamel damage
Acid
