MMI133 Lecture Notes - Lecture 15: Pyocyanin, Liposuction, Serotype

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20 Oct 2016

School

University of Alberta

Department

Medical Microbiology and Immunology

Course

MMI133

Professor

Judy Gnarpe

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Document Summary

Describe why the skin is a good barrier to infection. Identify the normal flora of the skin and give reasons why they survive on skin. Identify common eye infections, their causes and the results of disease (e. g. styes, blepharitis, conjunctivitis, keratitis, trachoma, inclusion conjunctivitis, ophthalmia neonatorum) Define terms used to describe rash lesions (i. e. macular, vesicular ) Identify characteristics of staphylococcus aureus and streptococcus pyogenes that make them major skin pathogens. Describe the diseases caused by rubeola & b-19 parvovirus. Important questions to think about when studying infectious disease. Washing reduces numbers but does not eliminate normal flora. Quickly re-establishes from hair follicles, sweat glands etc. Skin and mucous membranes ( internal skin ) largest organ of the body all skin diseases do not necessarily originate from the outside environment e. g. respiratory infections systemic infections. Skin is a physical and chemical barrier to infection. Both aerobic and some anaerobic bacteria grow in/on skin.

Related Questions

1. All of the following characteristics of skin help make it a good defensive barrier against pathogenic microbes EXCEPT:

Springy elasticity

Saltiness due to production of sweat from sweat glands

Acidic pH due to oily compound (sebum) metabolism

Normal microflora of skin

Constant sloughing off of old dead epithelial skin cells

2. The majority of microorganisms comprising the normal microflora inhabiting the skin surface are:

Gram-positive fungi of the single-celled yeasts

Gram-positive bacteria of the Staphylococcus, Micrococcus, Corynebacterium, and Proprionibacterium genera

Gram-negative bacteria of the Enterobacteriaceae family

Gram-negative bacteria of the Neisseria, Pseudomonas, and Salmonella genera

All of the above

3. The pus-producing skin infection (pyoderma) can be caused by:

Staphylococci

Streptococci

Corynebacteria

A combination of staphylococci, streptococci, and corynebacteria

All of these

4. Which of the following is NOT a characteristic of impetigo?

Common in children

Can be caused by Staphylococcus aureus

Can be caused by Streptococcus pyogenes

Is highly contagious

Can be caused by pseudomonads

5. Which of the following is NOT true about acne?

It is most commonly the result of male sex hormones that stimulate increased sebaceous gland growth and secretion of sebum.

Propionibacterium acnes in particular can turn a mild case of acne into a severe case by causing increased and widespread inflammation, tissue destruction, and scarring.

Common treatments are frequent cleansing of the skin and topical ointments that reduce the risk of infection.

Low doses of oral antibiotics are often prescribed to prevent bacterial infections of lesions and are without side effects.

In most cases, acne disappears or decreases in severity on its own as the body adjusts to the hormonal changes of puberty and sebaceous gland function stabilizes.

6. Which of the following often cause nosocomial infections in burn patients?

Streptococcus pyogenes

Serratia marcescens

Pseudomonas aeruginosa

Staphylococcus aureus

b and c

7. Gas gangrene is most likely associated with infection with:

Staphylococcus aureus

Clostridium perfringenes

Streptococcus pneumoniae

Neisseria gonorrhoeae

Pseudomonas aeruginosa

8. The leading cause of preventable blindness in the world is caused by:

Chlamydia trachomatis

Haemophilus influenzae

Neisseria gonorrhoeae

Staphylococcus aureus

Streptococcus pneumoniae

9. Chickenpox is a disease of chickens and is caused by the poxvirus, cowpox is a disease of cattle, and smallpox is a human disease that commonly affects only children. True or false?

10. Antibiotic is used to treat the eyes of newborn infants when:

The mother has gonorrhea

The mother has genital herpes

Neisseria gonorrhoeae is isolated from the newborn's eyes

Always

The mother has a history of multiple sex partners

11. The virus used to immunize individuals against smallpox causes the disease:

Chickenpox

Measles

Cowpox

Molluscum contagiosum

Warts

12. Which of the following fungal diseases result from an opportunistic fungal infection?

Zygomycoses

Aspergillosis

Candidasis

All of the above

None of the above

13. Rheumatic fever is caused by which organism?

Corynebacterium diphtheriae

Staphylococcus epidermidis

Staphylococcus aureus

Escherichia coli

Streptococcus pyogenes

14. Which of the following components of the respiratory system is normally free of microorganisms?

Lungs

Nasal cavity

Pharynx

Trachea

Bronchi

15. Which of the following is true about diphtheria?

It is caused by strains of Corynebacterium diphtheriae infected with a prophage that carries an exotoxin-producing gene.

A pseudomembrane composed of Corynebacterium diphtheriae cells, damaged epithelial cells, fibrin, and blood cells forms that can block the airway and cause suffocation.

The exotoxin spreads throughout the body damaging multiple organ system by interfering with cellular protein synthesis.

It can be prevented with DTP (diphtheria, tetanus, and pertussis) vaccine and treated with both antitoxin and antibiotics.

All of the above are true.

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1) What clinical manifestation do Staphylococcus aureus and Staphylococcus epidermidis share? A) nosocomial infections B) protein A antiphagocytic factor C) hyaluronidase enzyme D) enterotoxins E) staphylokinase 2) Which of the following has been historically classified as Gram-negative bacteria but is genetically more similar to low G + C Gram-positive bacteria? A) mycoplasmas B) Mycobacterium C) Clostridium D) Propionibacterium E) Nocardia 3) What is one virulence factor that differentiates Staphylococcus aureus from other species of staphylococci? A) It has a capsule. B) It can produce coagulase. C) It produces catalase. D) It can live on the surface of the skin and in cutaneous oil glands. E) It produces lipase. 4) Over 90% of Staphylococcus aureus isolates are penicillin-resistant. Why? A) They have loosely organized polysaccharide slime layers. B) They produce coagulase. C) Cell division occurs in successively different planes, and the daughter cells remain attached to one another. D) They produce Î²-lactamase. E) They produce staphylokinase, which dissolves fibrin threads in blood clots. 5) A woman comes to the emergency department with fever and vomiting. She soon develops a red rash all over her body, and her blood pressure begins to drop. What is one possible diagnosis? A) erysipelas C) scarlet fever B) endocarditis D) toxic shock syndrome E) staphylococcal food poisoning 6) Bacteria collected from a severely inflamed wound are sent to the lab for analysis. The results come back as follows: Gram-positive cocci in irregular clusters, kinase and coagulase positive, and able to grow in the presence of most antibiotics except vancomycin. The bacteria in the wound are most likely _______ A) Enterococcus. C) Staphylococcus aureus. B) Staphylococcus epidermidis. D) methicillin-resistant Staphylococcus aureus (MRSA). E) Streptococcus pyogenes (group A streptococcus). 7) Which of the following statements about "flesh-eating" streptococci is FALSE? A) It is caused by a group A streptococcus. B) It is also known as necrotizing fasciitis because it travels along the fascia. C) It causes death in over 50% of cases. D) It is considered a common complication of pyoderma. E) It involves toxemia. 8) Streptococcus agalactiae is associated with which of the following diseases? A) neonatal bacteremia B) neonatal meningitis C) neonatal pneumonia D) both neonatal bacteremia and neonatal meningitis E) neonatal bacteremia, neonatal meningitis, and neonatal pneumonia 9) What differentiates virulent strains of Streptococcus pneumoniae from nonvirulent strains? A) the species-specific teichoic acid present in its cell wall B) the type of Lancefield antigen it produces C) the presence of a polysaccharide capsule that protects it from digestion after endocytosis D) the type of toxins it produces E) the extent of the hemolytic zone it produces when it is grown on blood agar 10) Otitis media may lead to dangerous meningitis in children due to infection with _____ A) Streptococcus agalactiae. B) Streptococcus pneumoniae. C) Streptococcus mutans. D) Enterococcus. E) Mycoplasma pneumoniae. 11) Which of the following streptococci is associated with dental caries? A) viridans streptococci B) Streptococcus pyogenes C) Streptococcus pneumoniae D) Streptococcus equisimilis E) Streptococcus arginosus 12) Anthrax, which means "charcoal" in Greek, derives its name from _____ A) the airborne endospores it produces. B) the staining properties of the bacillus under the microscope. C) the black eschars it produces on human skin. D) its ability to invade the bloodstream and produce toxemia. E) the high mortality it causes in infected individuals. 13) Which of the following bacteria produce one of the most deadly bacterial toxins known? A) Clostridium perfringens C) Clostridium tetani B) Clostridium difficile D) Clostridium botulinum E) Corynebacterium species 14) Which of the following bacteria can cause life-threatening pseudomembranous colitis? A) Clostridium difficile B) Staphylococcus aureus C) Streptococcus pyogenes D) Enterococcus species E) Clostridium botulinum 15) How does the toxin from Clostridium tetani produce its action? A) It fuses irreversibly to neuronal cytoplasmic membranes, blocking release of acetylcholine at synaptic clefts. B) The smaller polypeptide of its toxin can block the release of inhibitory neurotransmitters by inhibitory neurons in the central nervous system, causing simultaneous contraction of both muscles in an antagonistic pair. C) It is a pyrogenic toxin, which triggers a diffused rash and, later, sloughing of skin. D) It destroys tissues, including muscle and fat. E) It produces antibodies that attack the neuromuscular junctions in skeletal muscle and prevent them from relaxing. 16) Listeria virulence is directly related to its ability to ______ A) produce powerful toxins. B) form very resistant endospores. C) live within cells and thus avoid exposure to the immune system of its host. D) easily become a pathogen in humans. E) resist most antimicrobial agents. 17) The pus from an abscess in a patient's jaw contains microbes that form yellowish grainy masses and appear filamentous under the microscope. Neither antifungal medication nor a normal course of antibiotics has been effective in treating the infection. The abscess is likely the result of infection with A) Actinomyces. B) Mycobacterium. C) Nocardia. D) Propionibacterium. E) Streptococcus. 18) What is the most common disease caused by Propionibacterium? A) acne B) food poisoning C) pneumonitis D) folliculitis 19) Streptococcus pneumoniae is a leading cause of ______ A) acne. C) pharyngitis B) furuncles. D) primary atypical pneumonia. E) otitis media. 20) The soil bacterium Nocardia asteroides can establish opportunistic infections of the _____ A) skin C) central nervous system B) lungs D) cardiovascular system. E) skin, lungs, and central nervous system

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16. All of the following are true about ear infections EXCEPT:

Middle ear infections (otitis media) often produce a puslike exudate (referred to as otitis media with effusion) due to infection by genera of Streptococcus, Haemophilus, or various species of anaerobes.

External auditory canal (otitis externa) infections are typically caused by Staphylococcus aureus or Pseudomonas aeruginosa.

After successful treatment of middle ear infections with antibiotics, sometimes tubes are inserted to prevent fluid accumulation, repeated infections, and hearing loss.

Pseudomonad infections are common in swimmers because these organisms are able to produce a soluble greenish-blue pigment.

Repeated ear infections in children often decrease markedly because as the child ages and the Eustachian tube changes shape and develops an angle that prevents most organisms from reaching the middle ear.

17. Why are colds difficult to treat and prevent?

Different cold viruses predominate during different seasons.

Because there are so many different types of rhino- and coronaviruses, each with different antigens, development and administration of vaccines are currently prohibitive.

Although some human interferons have been shown to block or limit rhinovirus infections, delivery to infection sites is difficult, and unwanted side effects can occur.

All of the above.

Both a and c.

18. Which of the following is NOT true about parainfluenza viruses?

Most infants by the age of 6 months have been exposed to and develop antibodies against all 4 parainfluenza viruses.

They cause rhinitis characterized by nasal, pharyngeal, and bronchial inflammation, primarily in children.

Parainfluenza virus infection can be prevented by vaccination.

They can cause noisy respiration (stridor) and acute obstruction of the larynx called croup.

The viruses are spread by direct contact or by large droplets.

19. In whooping cough, patients experience violent coughing episodes during the _________ stage and can have bluing of the skin or _________ due to lack of oxygen from massive mucus and bacterial airway blockage.

Paroxysmal; cyanosis

Catarrhal; pigmentation

Convalescent; osmosis

Pneumotic; hydrolysis

Primary; emesis

20. Penicillins have no effect on Mycoplasma pneumoniae because:

Mycoplasmas are viruses

Mycoplasmas possess beta lactamases

Mycoplasmas are too small

Mycoplasmas are eukaryotes

Mycoplasmas lack cell walls

21. How many cases of tuberculosis are reported globally each year?

10,000

100,000

3 million

10 million

22. Mycobacteria are difficult to Gram stain, and are termed âacid-fastâ due to their:

Ability to survive in acidic conditions

Resistance to drying

Thick, waxy cell walls

Resistance to sunlight

Lack of a peptidoglycan layer

23. Which of the following is true about pathogenic mycobacteria?

They have a long generation time of 12 to 18 hours.

They are obligate anaerobes sensitive to small amounts of oxygen.

They are highly resistant to drying and can remain viable in dried sputum 6 to 8 months later.

Both a and b.

Both a and c.

24. Clinical symptoms of tuberculosis are primarily due to:

Host inflammatory response

Mycotoxins

Endotoxin

Mucus production

Exotoxin

25. What characteristic of Coxiella burnetii, the causative agent of Q fever, allows it to survive for up to 2 years?

Metachromatic granule

Exotoxin

Endospore

Hemagglutinin

Cilia

26. The normal microflora of the heart includes species of:

Gram-positive bacteria

Gram-negative bacteria

Fungi

Viruses

None of these

27. Which of the following is commonly directly responsible for causing septic shock today?

Bacterial hemagglutinins

Bacterial endotoxins

Bacterial exotoxins

Fungal aflatoxins

Bacterial neurotoxins

28. All of the following are symptoms of septic shock EXCEPT

Shock

Lymphangitis

Chills

Fever

Collapsed blood vessels

29. What is the most likely explanation of how Streptococcus pyogenes causes rheumatic fever?

Strep throat infections migrate down to the heart.

Endotoxin production causes septicemia.

Vegetation followed by fibrin deposition.

Cross-reactivity of an antibody for a Streptococcus pyogenes antigen to a heart cell antigen.

It is an opportunistic infection triggered by coronary artery disease and atherosclerosis.

30. Bacterial endocarditis is an infection and inflammation of the lining and valves of the heart and occurs as a result of transient bacteria attaching to fibrin from exposed collagen fibers of damaged valvular surfaces. True or false?

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MMI133 Lecture Notes - Lecture 15: Pyocyanin, Liposuction, Serotype

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