Podcast
Questions and Answers
What is the primary antibody produced against Neisseria gonorrhoeae?
What is the primary antibody produced against Neisseria gonorrhoeae?
Meningitis occurs when the antibody response is high.
Meningitis occurs when the antibody response is high.
False
What is the causative agent of gonorrhea?
What is the causative agent of gonorrhea?
Neisseria gonorrhoeae
The major reservoir for Neisseria gonorrhoeae is ______.
The major reservoir for Neisseria gonorrhoeae is ______.
Signup and view all the answers
Which of the following characterizes meningococcemia?
Which of the following characterizes meningococcemia?
Signup and view all the answers
Match the following conditions with their characteristics:
Match the following conditions with their characteristics:
Signup and view all the answers
Neisseria meningitidis can be carried without symptoms.
Neisseria meningitidis can be carried without symptoms.
Signup and view all the answers
Infants are initially protected due to ______.
Infants are initially protected due to ______.
Signup and view all the answers
What mechanism is responsible for the wide range of activity against all β-lactams?
What mechanism is responsible for the wide range of activity against all β-lactams?
Signup and view all the answers
Resistance to β-lactam antibiotics is not observed in gram-negative bacteria.
Resistance to β-lactam antibiotics is not observed in gram-negative bacteria.
Signup and view all the answers
What is one way bacteria can prevent β-lactam antibiotics from reaching the PBP?
What is one way bacteria can prevent β-lactam antibiotics from reaching the PBP?
Signup and view all the answers
MRSA has acquired a new PBP that____________.
MRSA has acquired a new PBP that____________.
Signup and view all the answers
Match the following resistance mechanisms with their descriptions:
Match the following resistance mechanisms with their descriptions:
Signup and view all the answers
What bacteria family includes gram-negative rods and is known for requiring hemin and NAD?
What bacteria family includes gram-negative rods and is known for requiring hemin and NAD?
Signup and view all the answers
Which serotype of Haemophilus influenzae requires a capsule to cause disease?
Which serotype of Haemophilus influenzae requires a capsule to cause disease?
Signup and view all the answers
Meningitis vaccination can control healthy carriers of the disease.
Meningitis vaccination can control healthy carriers of the disease.
Signup and view all the answers
What is the primary characteristic of Haemophilus bacteria?
What is the primary characteristic of Haemophilus bacteria?
Signup and view all the answers
Nonencapsulated H. influenzae cannot cause disease.
Nonencapsulated H. influenzae cannot cause disease.
Signup and view all the answers
Haemophilus species require __________ for growth, which is also known as the V factor.
Haemophilus species require __________ for growth, which is also known as the V factor.
Signup and view all the answers
What is the common cause of meningitis in unvaccinated individuals or the elderly?
What is the common cause of meningitis in unvaccinated individuals or the elderly?
Signup and view all the answers
Match the following components with their characteristics:
Match the following components with their characteristics:
Signup and view all the answers
H. parainfluenzae is responsible for approximately ____% of saliva flora.
H. parainfluenzae is responsible for approximately ____% of saliva flora.
Signup and view all the answers
Which serotypes does the vaccine against Meningitidis cover for children older than 2 years?
Which serotypes does the vaccine against Meningitidis cover for children older than 2 years?
Signup and view all the answers
Match the following diseases with their corresponding potential complications from H. influenzae infections:
Match the following diseases with their corresponding potential complications from H. influenzae infections:
Signup and view all the answers
What was the incidence of systemic infections per year before the vaccination in 1987?
What was the incidence of systemic infections per year before the vaccination in 1987?
Signup and view all the answers
Haemophilus bacteria can form spores.
Haemophilus bacteria can form spores.
Signup and view all the answers
Why must sheep blood agar be heated before use?
Why must sheep blood agar be heated before use?
Signup and view all the answers
The capsule of Haemophilus influenzae contains polyribitol phosphate (PRP), which is a major virulence factor.
The capsule of Haemophilus influenzae contains polyribitol phosphate (PRP), which is a major virulence factor.
Signup and view all the answers
At what age can individuals receive the Haemophilus influenzae type B vaccine?
At what age can individuals receive the Haemophilus influenzae type B vaccine?
Signup and view all the answers
Which of the following antibiotics is a glycopeptide?
Which of the following antibiotics is a glycopeptide?
Signup and view all the answers
Vancomycin is effective against gram-negative organisms.
Vancomycin is effective against gram-negative organisms.
Signup and view all the answers
What is the primary reason aminoglycosides are ineffective against anaerobes?
What is the primary reason aminoglycosides are ineffective against anaerobes?
Signup and view all the answers
Bacitracin is commonly used as a topical treatment for ___ infections.
Bacitracin is commonly used as a topical treatment for ___ infections.
Signup and view all the answers
Match the following antibiotics with their classification:
Match the following antibiotics with their classification:
Signup and view all the answers
Which of the following statements about tetracyclines is true?
Which of the following statements about tetracyclines is true?
Signup and view all the answers
Polymyxin increases the permeability of the outer membrane, leading to cell death.
Polymyxin increases the permeability of the outer membrane, leading to cell death.
Signup and view all the answers
What side chain interaction does vancomycin interfere with?
What side chain interaction does vancomycin interfere with?
Signup and view all the answers
Which of the following is a standard culture medium for antimicrobial susceptibility testing?
Which of the following is a standard culture medium for antimicrobial susceptibility testing?
Signup and view all the answers
The McFarland turbidity standard is irrelevant to the preparation of inoculum for antimicrobial susceptibility testing.
The McFarland turbidity standard is irrelevant to the preparation of inoculum for antimicrobial susceptibility testing.
Signup and view all the answers
What does MIC stand for in the context of antimicrobial susceptibility testing?
What does MIC stand for in the context of antimicrobial susceptibility testing?
Signup and view all the answers
Standardized suspensions for inoculum preparation typically begin with a __________ standard number.
Standardized suspensions for inoculum preparation typically begin with a __________ standard number.
Signup and view all the answers
Match the type of antimicrobial test with its corresponding description.
Match the type of antimicrobial test with its corresponding description.
Signup and view all the answers
Who typically determines the antimicrobial susceptibility tests to perform?
Who typically determines the antimicrobial susceptibility tests to perform?
Signup and view all the answers
All laboratories use the same methods for antimicrobial susceptibility testing.
All laboratories use the same methods for antimicrobial susceptibility testing.
Signup and view all the answers
What is a common reason for using multiple colonies when preparing an inoculum?
What is a common reason for using multiple colonies when preparing an inoculum?
Signup and view all the answers
Study Notes
Neisseria, Haemophilus and Bordetella
-
These are gram-negative bacteria.
-
Neisseria:
- Anaerobic
- Gram-negative cocci, 0.6-1 µm in size
- Arranged in pairs with flattened sides
- Non-motile
- Catalase positive
- Oxidase positive
- Oxidize carbohydrates (do not ferment)
- Sugar used in presence of O2 to produce acid
- Some are normal flora of the upper respiratory tract
- Others are obligate human pathogens
- Two medically relevant species: N. meningitidis and N. gonorrhoeae
- N. meningitidis causes meningitis (nasopharynx colonization, but not always disease)
- N. gonorrhoeae causes gonorrhea (a common STD)
- N. gonorrhoeae is fastidious, requiring cysteine and lack of fatty acids in the growth medium, has an optimum growth temperature, and is difficult to grow. Easy to transmit person-to-person.
- Typical gram-negative: thin peptidoglycan + outer membrane
- LPS of Neisseria is called lipooligosaccharide (LOS)
- High branched sugar chains (oligosaccharides). Does lipid A have endotoxic effect?
- N. meningitidis: covered in carbohydrate capsule; N. gonorrhoeae: no true capsule, but sugars with negative charge on surface
- Surface and membrane proteins:
- Pili: attachment and transfer of genetic material.
- Porin: forms pores and channels in the outer membrane
- Rmp protein: antibodies interfere with other antibodies, yet antibodies may help pathogenesis
- Requires iron.
- Produce IgA protease: inactivates IgA.
- Surface proteins mediate attachment and penetration of host cells
- Meningococcal pili preferentially bind cells in nasopharynx
- N. gonorrhoeae: internalized by phagocytes and survives
- LOS from both pathogens stimulates inflammation; IgG is the primary antibody produced against N. gonorrhoeae, also targeting Omp's, LOS, pili, and capsule
- Protection against meningococci: humoral or cellular?
- Meningitis occurs when antibody response is low (ex. children), and some infants are initially protected.
- N. meningitidis (a.k.a. the “meningococcus”): can be carried without symptoms, has a large antiphagocytic capsule, and is very sensitive to temps above or below 37˚C. It can undergo autolysis. Colonizes the nasopharynx. Meningococcal meningitis (inflammation of meninges) and meningococcemia (characterized by skin lesions) cause of these illnesses in humans. Can survive in immune cells.
- Meningitis: mildest form, fever and malaise, resolving in 1-2 days; fulminant form is fever, vomiting, headache, seizure, coma. Infants have initial symptoms of fulminant meningitis. Progressive neurological damage, convulsions, spinal rigidity, hamstring spasms, can kill. Meningococcemia: septicemia but no meningitis.
- Haemorrhages of skin (30% to 60% of patients), pulmonary insufficiency, death in 24 hours possible.
-
Haemophilus:
- Gram-negative rods: outer membrane with LPS (endotoxin), strain-specific proteins.
- Non-spore formers
- Non-motile
- Aerobic or Facultative anaerobes
- Fastidious
- Requires hemin (X factor) and NAD (V factor). Must be heated first.
- Some have a capsule (6 different serotypes). Non-encapsulated still cause disease
- 1 serotype vaccine: type B
- Commonly colonize mucous membranes of upper respiratory tract (healthy): H. parainfluenzae and nonencapsulated H. influenzae
- H. parainfluenzae 10% of saliva flora
- Local spread possible (otitis media, sinusitis, bronchitis, pneumonia)
- Disseminated disease is rare
- Most common disease causing serotype: H. influenzae serotype B
- Uncommon in upper respiratory tract.
- Vaccine available (1987) but limited to those 2 months of age and older
- 20,000/year infections occurring in the developing nations 3 million case/year infection
- Epidemiology: primarily affects unvaccinated children, similar symptoms of other types of bacterial meningitis, and 1-3 day initial mild symptoms of meningitis.
- Recovery: with proper intervention, 90% have favorable outcomes
- Epiglottitis, a life-threatening inflammation of epiglottis (cartilage structure).
- Arthritis: prevalent before vaccine at <2 yrs of age and characterized by pain swelling in joints with inflammation.
- Non-encapsulated: otitis, sinusitis and lower respiratory tract infections
- Acute conjunctivitis, H. aegypticus: contagious inflammation of membrane lining eyelid and whites of eyes.
- Chancroid (STD), H. ducreyi: genital sore that ulcerates (2 days)
- Laboratory diagnosis: sample fluid (CSF), microscope (sensitive and specific), culture use supplements (chocolate or Levinthal's agar, Staphylococci); agglutination
- Treatment/prevention: antibiotics (cephalosporins) vaccine (against H. influenzae type B - conjugate of pure capsular PRP); 3 doses before 6 months of age.
-
Bordetella:
- Gram-negative coccobacillus; strict aerobes
- Simple nutritional requirements. Charcoal, starch, blood included to absorb any toxic compounds
- Most important species: B. pertussis, major disease: whooping cough, exclusive human pathogen; vaccine available (DTP), Still ~60 million cases/year worldwide, 12,000 cases/US.
- Distinguished from other Bordetella species by oxidase + test, urease - test, non-motile, and no growth on sheep blood agar.
- B. pertussis inhaled into respiratory tract,
- Binds to ciliated cells lining airways
- Damage cell (3 toxins)
- Pertussis toxin, a two-component toxin, that enters cells to increase respiratory secretions/mucus.
- Tracheal toxin, directly interferes with DNA of ciliated cells, to inhibit cilia and eventually destroy ciliated cells.
- Hemagglutinin, promoting binding to membranes of ciliated cells by increasing mucus.
- Disease progression: 7-10 day incubation after inhalation, 3 stages
- Catarrhal: peak bacteria, disease may not yet be diagnosed (high infectivity)
- Paroxysmal: coughing attacks, mucus clearance impaired, vomiting and exhaustion, and 40-50 paroxysms/day
- Convalescent: cough stops, paroxysms subside, secondary complications possible
- Specimen collection and diagnosis (to avoid drying/exposure to drying and cold temperatures): nasopharyngeal (no cotton swabs due to toxic fatty acids present), plate immediately in specialized transport media, use chocolate or Regan-Lowe charcoal agar, microscopy (fluorescent antibodies)
- Treatment: Supportive therapy (antibiotics, macrolides (e.g., erythromycin, azithromycin), dosage inactivated pertussis toxin + bacterial component of vaccine); 1-5 doses; 2, 4, 6, 15 months and one between 4-6 yrs (DTaP), booster for adolescents and pregnant women
- Recent outbreaks (2011-2012) due to elevated awareness (improved diagnostic testing, better reporting) and circulation of bacteria. Wiping immunity from vaccines. Infants and very young children - highest risk for serious illness. BUT: adolescent cases (13-14 yrs old) increasing.
-
Legionella:
- Gets name from the first outbreak of Legionnaires Disease in American Legion 1976.
- Gram-negative, poorly staining
- Pleomorphic coccobacilli rods (long/slender)
- Obligate aerobes, nutritionally fastidious
- Requires L-cysteine and iron and a buffered charcoal yeast extract agar.
- Water, lakes, cooling towers / air conditioners, showers, hot tubs - often sources of contamination
- Not spread human to human
- L. pneumophila likely disease; causes Legionnaires disease and Pontiac fever (18,000 cases/year in US)
- Affects free-living amoeba in nature and biofilms.
- Infects alveolar macrophages, monocytes, and epithelial cells
- Survives intracellularly by preventing lysosomal fusion (survives within body cells)
- Legionnaires disease: 1-10 days, severe form of pneumonia, multiorgan infection
- Pontiac fever: 1-2 days, high fever, chills, headache, no pneumonia
- 15% death in healthy, 75% in immunocompromised.
- Diagnostics:
- Microscopy: poor staining, hard to find in tissue sections
- Culture: buffered charcoal yeast extract agar; grow for 3-5 days
- Media requires (L-Cysteine and iron)
- Test growth with/without supplements
- Sheep's blood agar, not helpful.
- Serological testing (ex. Legionella urinary antigen test), for initial detection, useful
- Nucleic acid amplification (ex. PCR) for respiratory samples and water
- Antibody titers (useful to detect prior exposure)
- Treatment: macrolides or fluoroquinolones
- Prevention and screening: water cooling towers - tested by labs, water systems in hospitals/ nursing homes treated (hyperchlorination, heating, biocides, and coper-silver ionization)
-
Corynebacterium:
- Gram-positive rods; clumps, short chain (V or Y arrangement), irregular / club-shaped
- Aerobic or facultative anaerobes, catalase +
- Do not form spores
- Unique cell wall (diaminopimelic acid and mycolic acid)
- Stain with Methylene Blue (Metachromatic granules inside some bacteria)
- Normal colonizers (skin, upper RT, GI, or urogenital)
- Opportunistic pathogens
- Pathogen: C. diphtheriae causes diphtheria.
- Irregular-club shaped rods
- Metachromatic granules visible after staining with methylene blue
- Granules: inorganic polyphosphates (volutin); serve as energy reserves. Not membrane bound.
- Two-component exotoxin, encoded by bacteriophage. Expressed when iron concentrations are low.
- Enter target cells, stops protein synthesis in cell.
- Phospholipase (D): increases permeability of blood vessels
- Allows organism to spread within the nasopharynx
- Epidemiology: asymptomatic carriage in throat, spread via respiratory droplets.
- Sore throat, low-grade fever may occur. Grey pseudomembrane over throat. - Bacteria, lymphocytes, plasma cells, fibrin, and dead cells
- Toxin causes vessel damage, bleeding, myocarditis, trouble breathing; spreads through blood (body); death can occur from toxin-mediated heart failure
- Diagnostics:
- Microscopy: methylene blue stain (showing metachromatic granules); Gram stain for Gram-positive pleomorphic rods arranged in irregular formation.
- Culture: cysteine or serum tellurite agar (gray to black colonies). Tellurite in media, which is reduced intracellularly to tellurium.
- Differentiated from Arcanobacterium and C. pseudotuberculosis (box 27.1): testing for the presence of DAP (diaminopimelic acid) in the cell wall.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on Neisseria gonorrhoeae, its antibody responses, and meningitis. This quiz covers various characteristics of these bacteria and their resistance mechanisms. Additionally, it explores vaccination and symptomless carriers related to these pathogens.
