Micro lecture exam 3 Flashcards
what are two Bacillus species?
Bacillus anthracis and Bacillus cereus
what is the action of the botulin toxin?
causes a flaccid paralysis by inhibiting acetylcholine release in the neuromuscular junction
Gas gangrene is caused by…
Clostridium perfringens
Which of the following is not classified as an unevenly staining non-spore forming Gram-positive bacilli?
Corynebacterium
Propionibacterium
Mycobacterium
Listeria
Nocardia
Listeria
Leprosy is a communicable disease, however, approximately 95% of the human population have a natural immunity?
True or False
True
What is the name of the human anthrax vaccine?
Biothrax
The genera of human pathogens that produce endospores include…
Bacillus and Clostridium
The human anthrax vaccine is readily available for travelers and civilians.
True or False
False
Bacillus cereus is a gram positive motile rod.
True or False
True
______ are often _______ to prevent the spread of Erysipelothrix rhusiopathiae which causes a specific type of cellulitis.
Pigs/vaccinated
what are the 2 gram-positive regular non-sporeforming bacilli?
Listeria monocytogenes and Erysipelothirx rhusiopathiae
Genus Bacillus fill in the blank
1. primary habitat is _____
2. ____ and ___ positive
3. source of _______
4. versatile in degrading ______ _______
5. gram-____
motile or nonmotile?
endospore-forming or nonendospore-forming?
- soil
- aerobic/catalase
- antibiotics
- complex macromolecules
- gram positive
motile/endospore forming
Central spores in Bacillus anthracis develop under all conditions except in…
the living body
what are the virulence factors of Bacillus anthracis?
polypeptide capsule and exotoxins
what was anthrax thought of for years and how can humans get anthrax?
was thought of as a Zoonotic disease and it is acquired through contact with animals (sheep, cattle, goats) and their hides
what organism did Robert Kich work with for his postulates and proving the germ theory?
Bacillus anthracis
Human infection for anthrax depends on what 3 different portal of entries?
cutaneous- spores enter through the skin; least dangerous
pulmonary- inhalation of spores; most deaths
gastrointestinal- ingested spores; least common
what are the symptoms of cutaneous anthrax?
small papule or blisters that may itch; progress to a black eschar
20% fatality
what is pulmonary anthrax also called and what are it’s signs and symptoms?
also called woolsorter’s disease
early symptoms: fatigue, malaise, fever, aches, cough
late symptoms: high fever, labored breathing, shock
rapid death in 99% of untreated cases
causes- capillary thrombosis/cardiovascular shock
what is gastrointestinal anthrax’s symptoms and fatality rate?
symptoms: flu-like symptoms with fever and tiredness, sore throat, neck swelling, difficulty swallowing, nausea, anorexia, abdominal pain, vomiting & diarrhea
25% - 60% fatality
no cases reported in US
what are the antibiotic treatments for Bacillus anthracis and do they counteract the toxin?
ciprofloxacin or doxycycline and it does not
Name 3 facts regarding Bacillus anthracis and animals
- animals that have died from anthrax are burned or chemically decontaminated before burial
- vaccine for animals
- imported products composed of animal hides and hair should be gas-sterilized (ethylene oxide)
what is the the new drug approved by FDA for pulmonary anthrax and what does it do?
Raxibacumab; monoclonal antibodies bind to exotoxin
what happened in history regarding Bacillus anthracis?
2001- mailing of anthrax- containing envelopes
Destination: journalists offices and government offices
This Bacillus is commonly airborne and dustborne. The usual methods of disinfection and antisepsis are ineffective.
Bacillus cereus
where does bacillus cereus multiply and survive?
multiplies readily in cooked foods like rice, potato, and meat dishes
spores survive cooking (short periods) and reheating
food stored at room temperate spores germinate and produce enterotoxin
what are the symptoms of Bacillus cereus if ingested and how long do these symptoms last?
is there any treatment?
symptoms: nausea, vomiting, abdominal cramps, diarrhea; 24-hour duration
no treatment
where has Bacillus cereus been increasingly reported?
in immunosuppressed, intubated patients and drig addicts
what causes listeriosis?
Listeria monocytogenes
What are the initial symptoms of Clostridium perfringens?
pain, edema, bloody exudate in lesion w/ fever, tachycardia, blackened necrotic tissue w/ gas bubbles
What is the difference between Anaerobic cellulitis and Myonecrosis?
both are bacteria spreading in necrotic muscle tissue but Myonecrosis can invade healthy healthy tissue and Anaerobic cellulitis remains localized
How can you get infected with C. perfringens
-surgical incision
-puncture
-gunshot wound
-crushing trauma
-compound fracture
-diabetic sore
-frostbite
-septic abortions
What is the treatment for C. perfringens?
immediate cleaning of wound, debridement, or amputation
-large doses of cephalosporin or PCN
-no vaccine available
Describe Genus Clostridium
Gram +, spore forming rods
-strict anaerobic; oval/spherical spores
-synthesize organic acids, alcohols, exotoxins
cause wound & tissue infx and food intoxication
What does Clostridium tetani cause and what are the symptoms
causes tetanus
Symptoms: clenching of jaw, arching of back, flexion of arms, extension of legs; death due to paralysis in respiratory mucles
What is the action of neurotoxin Tetanospasmin
blocking the release of inhibitory neurotransmitters
-causes paralysis by binding to motor nerve endings in spinal cord
-rigid paralysis (muscles contract uncontrollably)
How do you treat C. tetani and what is the vaccine you get?
Control infection with PCN or tetracycline, and muscle relaxers
Toxoid vaccine DTaP (2, 4, 6, 15 months, 5yrs, booster q10yrs)
What is the fatality of C. tetani?
10-70%
What does Clostridium difficile-Associated Disease (CDAD) cause?
causes antibiotic-associated (pseudomembranous) colitis
Where does C. difficile usually reside and how do you acquire it?
-Normal resident of colon; kept in low numbers
Acquired: treatment with broad-spectrum antibiotics kills other bacteria, allowing C. diff to overgrow=superinfection
What are the symptoms of C. diff?
diarrhea, abdominal cramps, fever, patches of colon lining sloughs off
*common in community-acquired diarrhea
what does C. diff produce?
enterotoxins
What is the treatment and prevention for C. diff?
Mild: fluid & electrolyte replacement; withdrawal of antimicrobials
Severe: oral vancomycin or metronidazole & replacement cultures
Prevention: bleach cleaners
What are the 2 Clostridial Food poisoning?
C. botulinum & C. perfringens
What are the 3 type of Botulism?
-Foodborne
-Infant
-Wound
How do you get Foodborne botulism and what are the symptoms?
eating home canned food
Symptoms: double vision, difficulty swallowing & speaking, nausea, vomiting, muscular & respiratory paralysis
How would Infant botulism occur and what are the symptoms?
affects ages 2 weeks-6 months
-ingest spores: raw honey, dust, vegetables
Symptoms: appear lethargic, feeding poorly, weak cry, appearing “floppy”
What is wound botulism and who is at risk?
spores enter wound and cause food poisoning symptoms
At risk: injection drug uses, traumatic wound, surgery
What is the treatment and mortality rate for C. botulinum?
-PCN and CDC has antitoxin
-Respiratory & cardia support
5% mortality rate
Describe Botox (botulin A or B)
-initially used for crossed eyes & uncontrollable muscle spasm in back
-“lunch hour facelift” before FDA approval 2002
-helps with headaches & migraines (approval 2012)
-temporary paralysis in facial muscles to prevent wrinkles
Aside from gas gangrene what else does C. perfringens cause?
Clostridial gastroenteritis
Describe clostridial gastroenteritis
most common foodborne illness in US (1 million cases a year)
How do spores contaminate food for C. perfringens?
commonly raw meat and poultry that hasn’t been cooked thoroughly
-spores germinate and multiply if unrefrigerated
Where does the toxin produced in C. perfringens (clostridial gastroenteritis)?
toxin is produced in the intestine; acts on epithelial cells
What is the treatment for Clostridial gastroenteritis?
Rapid recovery and no abx needed, but may need fluid and electrolytes
Genus Mycobacteria: Acid-Fast Bacilli (fill in the blank)
Acid-fast staining
1. Gram-_____, _______ bacilli
2. strict _______
3. produce ________
4. Possess ______ acids and a waxy cell wall
5. Do not form _______, ______, or spores
6. Grow ______
- positive, irregular
- aerobes
- catalase
- mycolic
- capsules, flagella
- slow
What does Mycobacterium tuberculosis produce?
no exotoxins or enzymes that contribute to infectiousness
What are the virulence factors of M. tuberculosis?
contain complex waxes= mycolic acids and cord factor prevent destruction by lysosomes or macrophages
What are predisposing factors of M. tuberculosis? How is it transmitted?
-inadequate nutrition, debilitation of the immune system, poor access to medical care, lung damage, and genetics
-airborne respiratory droplets; 5-10% of infected people develop disease
the primary reservoir for Listeria monocytogenes is..
what can it contaminate?
…soil and water/animal intestines
contaminate foods and grow during refigeration
what is the virulence for Listeria monocytogenes?
ability to replicate in the cytoplasm of cells after inducing phagocytosis; avoids humoral immune system
Listeria monocytogenes cases are mostly associated with….
consuming dairy products, poultry, and meat
what are the treatment and prevention for Listeria monocytogenes?
RX: Ampicillin (pcn) or trimethoprim/ sulfamethoxazole (Bactrim)
Prevention: pasteurization and cooking
what are the 3 groups of individuals who acquire Listeria monocytogenes (1-4 weeks after eating food)?
what are the symptoms?
- often mild or subclinical in healthy adults: fever, diarrhea, sore throat
- immunocompromised patients: headache, stiff neck, confusion, loss of balance, convulsions; affects brain and meninges; 20% fatality
- pregnant women: flu-like symptoms
crosses the placenta or through the birth canal
affects fetuses and neonates- can cause miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn
what does Erysipelothrix rhusiopathiae cause?
erysipeloid (cellulitis)
what is Erysipelothrix rhusiopathiae’s portal of entry and what does it produce? and who is most at risk?
enters through skin abrasion and multiplies to produce dark red lesions
most at risk who handle animals, carcasses and meats
how do you treat Erysipelothrix rhusiopathiae?
PCN or erythromycin
Erysipelothrix rhusiopathiae is gram_____
Distributed in animals and the environment mostly _____, _____, ______
positive
pigs, fish, poultry
what are the 5 medically important gram-positive irregular non-spore-forming bacilli?
Corynebacterium
Propionibacterium
Mycobacterium
Actinomyces
Nocardia
what causes acne?
Propionibacterium acnes
name the treatment for
mild acne-
moderate acne-
severe acne-
mild acne- salicylic acid
moderate acne- antibiotics clindamycin, acne creams benzoyl peroxide
severe acne- isotretinoin
Propionibacterium acnes is gram positive _____ rods; ______ arrangement
pleomorphic/ palisade
Propionibacterium acnes is common resident of _______ and it secretes enzymes that….
pilosebaceous glands
…damage the hair follicle that can lead to scaring
Propionibacterium acnes are aerotolerand or anaerobic
true or false
true
what does Corynebacterium diphtheriae cause and how is it acquired?
diphtheria
acquired: respiratory droplets from healthy carriers or actively infected individuals
what are the 2 stages of Corynebacterium diphtheriae-diphtheria and describe them.
- local infection- upper respiratory tract infection
symptoms: sore throat, nausea, vomiting swollen lymph nodes
bacteria grow and produce diphtherotoxin
Diphtherotoxin destroys healthy tissues in the respiratory system. 2-3 days pseudomembrane is formed (thick, gray coating) and builds up in nose and throat
covers tissues in nose, tonsils, voice box, throat-making it very hard to breath - systemic effects by diphtherotoxin-
myocarditis with abnormal rhythms, leads to heat failure
neuritis
paralysis of soft palate, eye muscles, limbs, diapgram= respiratory failure
secondary pneumonia
what is the treatment for Corynebacterium diphtheriae- diphtheria?
*PCN or erythromycin
*antitoxin (from CDC)
*Surgically open blocked airway or tracheostomy
*vaccine: DTaP (diphtheria vaccine used in early thirties)
what is cutaneous diphtheria?
*caused by a strain of Corynebacterium diphtheriae without the gene to make diphtheria
*mostly seen in the tropics/ US homeless people
*Symptoms: scaling rash/ulcers with clearly demarcated edges
*sometimes maybe coinfect with other species
Clinical tuberculosis divided into:
-Primary TB
-Secondary TB (reactivation or reinfection)
-Disseminated (extrapulmonary) TB
What is another name for Primary TB
Latent TB infection
What’s the chance of primary TB to develop to secondary TB?
only 5-10%
What is the infectious dose of primary TB?
10 cells
After 3-4 weeks after being infected with primary TB the immune system attacks, forming tubercles. What happens if the tubercle breaks down?
If it breaks into necrotic caseous lesions, they gradually heal by calcification
What are the symptoms of primary TB?
there’s no symptoms, cannot spread TB bacteria, but will have a positive skin test
what are symptoms for secondary TB (TB disease)
violent coughing greenish or bloody sputum, fever, anorexia, weight loss, fatigue, night sweats
If TB is untreated, what is the mortality rate?
60%
TB bacteria remains in the lungs for majority of 85% patients, what happens to the other 15%?
bacteria moves to the other parts of the body
What happens to the tubercules in secondary TB?
tubercules expand and drain into the bronchial tubes and upper respiratory tract
What’s another name for disseminated TB?
Extrapulmonary TB
True or False
During secondary TB, bacilli disseminate to regional lymph nodes, kidneys, long bones, genital tract, brain, and meninges. They create tubercle in these organs
True
What tests are done to diagnose TB?
- In vivo or tuberculin testing
-Mantoux test (PPD) - x-rays
- direct identification of acid-fast bacilli in specimen
- cultural isolation and biochemical testing
What is the management and prevention of M. tuberculosis?
-treat 8 weeks with4 drugs
-one pill regimen called Rifater = isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), plus ethambutol (EMB
-then 18 weeks of INH and RIF
What vaccine is for M. tuberculosis?
BCG vaccine
What are two types of resistant M. tuberculosis?
*MDR-TB - multidrug-resistant TB
*XDR-TB - extremely drug resistant TB
-resistant to INH and RIF
what is tuberculoid leprosy?
asymmetrical, shallow lesions, damage nerves- results in local loss of pain receptors
have fewer complications and more easily treated.
what are skin lesions?
thin granulomas fewer bacilli, not progressive
what is lepromatous leprosy?
*a deeply nodular infection that causes severe disfigurement of the face and extremities, widespread dissemination
*advanced cases have loss of feeling and tissues waste away in hand and feet due to loss of nerve function
*cooler region of body- thick granulomas= lepromas with more bacilli
how do you diagnose tuberculoid leprosy and lepromatous leprosy?
*detection of acid-fast bacilli in skin lesions, nasal discharges, and tissue samples
*numbness in hands and feet, loss of heat and cold sensitivity, muscle weakness, thickened earlobes, chronic stuffy nose
*patient history
how do you treat tuberculoid leprosy?
Rifampin + dapsone for 12 months
how do you treat lepromatous leprosy?
1.) Rifampin + dapsone + clofazimine for minimum of 2 years
2.) then dapsone for 10 years
Is there a vaccine for tuberculoid leprosy and lepromatous leprosy?
no vaccine available
India and Brazil use the tuberculosis vaccine for Hansen’s disease.
What is Mycobacterium leprae?
causes Hansen’s Disease (leprosy)
strict parasite- has not been grown on artificial media or tissue culture.
slowest growing of all species; 30 degrees Celsius
100 cases per year in US; in the south, Cali, Hawaii
common: temperate, tropical and sub-tropical climates
what is the course of infection for Mycobacterium leprae?
macrophages phagocytize the bacilli, but a weakened macrophage or slow T cell response may not kill bacillus.
incubation from 2-5 years years; if untreated, bacilli grow slowly in the skin macrophages and Schwann cells of peripheral nerves.
