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Questions and Answers
What type of bacteria does Listeria monocytogenes belong to?
What type of bacteria does Listeria monocytogenes belong to?
What is a characteristic feature of Listeria monocytogenes?
What is a characteristic feature of Listeria monocytogenes?
What is the most common source of Listeria monocytogenes infection?
What is the most common source of Listeria monocytogenes infection?
What is the recommended treatment for Listeria monocytogenes infection?
What is the recommended treatment for Listeria monocytogenes infection?
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What is the significance of Listeria monocytogenes being psychrotrophic?
What is the significance of Listeria monocytogenes being psychrotrophic?
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What is a common food source associated with Listeria monocytogenes outbreaks?
What is a common food source associated with Listeria monocytogenes outbreaks?
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What is the outcome of Listeria monocytogenes infection in immunocompetent individuals?
What is the outcome of Listeria monocytogenes infection in immunocompetent individuals?
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What was the outcome of the 2011 Listeria monocytogenes epidemic?
What was the outcome of the 2011 Listeria monocytogenes epidemic?
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What was the outcome of the listeria outbreak in 2011?
What was the outcome of the listeria outbreak in 2011?
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What was the primary cause of the listeria contamination in the cantaloupes?
What was the primary cause of the listeria contamination in the cantaloupes?
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What was the outcome of the Jensens' initial plea to the charges?
What was the outcome of the Jensens' initial plea to the charges?
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What was the maximum sentence the Jensens faced for their conviction?
What was the maximum sentence the Jensens faced for their conviction?
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What was the consequence of the listeria outbreak for the Jensens' business?
What was the consequence of the listeria outbreak for the Jensens' business?
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What was the reason for the Jensens' lawsuit against the Primus Group?
What was the reason for the Jensens' lawsuit against the Primus Group?
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What was the consequence of the listeria outbreak for one of the victims?
What was the consequence of the listeria outbreak for one of the victims?
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What was the charge the Jensens were convicted of?
What was the charge the Jensens were convicted of?
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What is the estimated mortality rate of diphtheria even with treatment?
What is the estimated mortality rate of diphtheria even with treatment?
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What is the characteristic of the lactic acid bacteria?
What is the characteristic of the lactic acid bacteria?
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What is the function of the B domain of the diphtheria toxin?
What is the function of the B domain of the diphtheria toxin?
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Which of the following bacteria is NOT a high GC gram positive bacteria?
Which of the following bacteria is NOT a high GC gram positive bacteria?
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What is the purpose of the Elek test?
What is the purpose of the Elek test?
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What is the recommended treatment for diphtheria?
What is the recommended treatment for diphtheria?
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What is the characteristic of Actinomycetes?
What is the characteristic of Actinomycetes?
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What is the role of toxin in the pathology of Diptheria?
What is the role of toxin in the pathology of Diptheria?
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What is the mode of action of the diphtheria toxin?
What is the mode of action of the diphtheria toxin?
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What is the source of the diphtheria toxin?
What is the source of the diphtheria toxin?
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What is the characteristic of Corynebacterium diptheriae?
What is the characteristic of Corynebacterium diptheriae?
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What is the purpose of the Gram stain or methylene blue in diagnosing diphtheria?
What is the purpose of the Gram stain or methylene blue in diagnosing diphtheria?
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What is the mode of transmission of Diptheria?
What is the mode of transmission of Diptheria?
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What is the characteristic of the pseudomembrane formed in Diptheria?
What is the characteristic of the pseudomembrane formed in Diptheria?
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What is the approximate lethal dose of the diphtheria toxin for humans?
What is the approximate lethal dose of the diphtheria toxin for humans?
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What is the effect of the toxin produced by Corynebacterium diptheriae?
What is the effect of the toxin produced by Corynebacterium diptheriae?
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Streptomyces is a type of low GC gram-positive bacteria.
Streptomyces is a type of low GC gram-positive bacteria.
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Clostridium is a type of non-spore forming bacteria.
Clostridium is a type of non-spore forming bacteria.
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Corynebacterium diptheriae is a type of fungus.
Corynebacterium diptheriae is a type of fungus.
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Diphtheria is a lower respiratory tract illness.
Diphtheria is a lower respiratory tract illness.
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The toxin produced by Corynebacterium diptheriae is absorbed onto the skin and causes destruction of epithelium.
The toxin produced by Corynebacterium diptheriae is absorbed onto the skin and causes destruction of epithelium.
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The pseudomembrane formed in diphtheria is yellowish in color.
The pseudomembrane formed in diphtheria is yellowish in color.
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Streptomyces produces antibiotics in the roots of plants.
Streptomyces produces antibiotics in the roots of plants.
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The brothers initially pleaded guilty to the charges of introducing adulterated food into interstate commerce.
The brothers initially pleaded guilty to the charges of introducing adulterated food into interstate commerce.
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The Jensens faced sentences of up to 10 years in federal prison for their conviction on all six counts.
The Jensens faced sentences of up to 10 years in federal prison for their conviction on all six counts.
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Mycoplasma is a type of high GC gram-positive bacteria.
Mycoplasma is a type of high GC gram-positive bacteria.
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The listeria outbreak led to the hospitalization of 147 people across 30 states.
The listeria outbreak led to the hospitalization of 147 people across 30 states.
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The Jensens filed for bankruptcy in 2010 and suspended farming after lawsuits were filed by people sickened or whose family members died from listeria infections.
The Jensens filed for bankruptcy in 2010 and suspended farming after lawsuits were filed by people sickened or whose family members died from listeria infections.
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The Jensens sued a food safety audit firm, the Primus Group, because they did not approve the cleaning operation.
The Jensens sued a food safety audit firm, the Primus Group, because they did not approve the cleaning operation.
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The listeria outbreak led to the death of 30 people.
The listeria outbreak led to the death of 30 people.
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The Jensens used a chlorine spray feature to clean their cantaloupes.
The Jensens used a chlorine spray feature to clean their cantaloupes.
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The Jensens began washing their cantaloupes with devices used to clean potatoes in April 2011.
The Jensens began washing their cantaloupes with devices used to clean potatoes in April 2011.
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Diphtheria toxin is encoded by a virulent phage.
Diphtheria toxin is encoded by a virulent phage.
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The lethal dose of diphtheria toxin for humans is approximately 1 μg/kg.
The lethal dose of diphtheria toxin for humans is approximately 1 μg/kg.
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Antitoxin is used as a vaccine for diphtheria.
Antitoxin is used as a vaccine for diphtheria.
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Diphtheria toxin ADP-ribosylates elongation factor EF1.
Diphtheria toxin ADP-ribosylates elongation factor EF1.
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The Elek test is used to diagnose diphtheria.
The Elek test is used to diagnose diphtheria.
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Listeria monocytogenes is a type of low GC gram-positive bacteria.
Listeria monocytogenes is a type of low GC gram-positive bacteria.
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Diphtheria is treated with antibiotic only.
Diphtheria is treated with antibiotic only.
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The mortality rate of diphtheria even with treatment is 1-2%.
The mortality rate of diphtheria even with treatment is 1-2%.
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Listeria monocytogenes can cause meningitis and sepsis in immunocompetent individuals.
Listeria monocytogenes can cause meningitis and sepsis in immunocompetent individuals.
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Loeffler's serum media is a selective media for Corynebacterium diptheriae.
Loeffler's serum media is a selective media for Corynebacterium diptheriae.
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Listeria monocytogenes is a psychrophilic bacterium.
Listeria monocytogenes is a psychrophilic bacterium.
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The main reservoir of Listeria monocytogenes infection is infected humans.
The main reservoir of Listeria monocytogenes infection is infected humans.
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Penicillin and gentamicin are effective against Listeria monocytogenes.
Penicillin and gentamicin are effective against Listeria monocytogenes.
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Listeria monocytogenes can cause death in immunocompetent individuals.
Listeria monocytogenes can cause death in immunocompetent individuals.
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Listeria monocytogenes is a type of spore-forming bacteria.
Listeria monocytogenes is a type of spore-forming bacteria.
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The 2011 epidemic of Listeria monocytogenes resulted in 33 deaths.
The 2011 epidemic of Listeria monocytogenes resulted in 33 deaths.
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Study Notes
Gram-Positive Bacteria
- Firmicutes:
- Low GC gram-positive bacteria
- Examples: Lactic acid bacteria (Streptococcus, Lactobacillus), Staphylococcus, Listeria, Mycoplasma
- Actinobacteria:
- High GC gram-positive bacteria
- Examples: Streptomyces, Corynebacteria, Mycobacteria
Listeria
- Non-spore forming, gram-positive, non-motile rods
- Causes listeriosis
- Important cause of disease in humans and animals
- L. monocytogenes: short, gram-positive, non-spore forming rod; catalase positive, facultative anaerobe; tumbling motility at room temperature but not at 37°C
Listeriosis
- Two types:
- Perinatal:
- Early onset: intrauterine infection, sepsis, and death before birth
- Late onset: infected at birth, meningitis, and sepsis within 2-3 weeks
- Adult:
- Flu-like symptoms and gastro upset in immunocompetent individuals
- Meningo-encephalitis and bacteraemia in immunocompromised individuals
- Perinatal:
- Treatment: penicillin and gentamicin (gentamicin does not enter host cells)
- Source of infection: environment, animals, silage, infected humans
- Normal route of infection: gastrointestinal
- Outbreaks associated with dairy products, packaged meat, and fruit and vegetables
- Prevention: pasteurization of dairy foodstuffs and cooking of food
2011 Epidemic
- 33 deaths and 147 confirmed cases
- Listeria-contaminated cantaloupes killed 33 people
- Two Colorado farmers pleaded guilty to federal criminal charges
Pathogenesis of Listeria
- Infection leads to meningitis and sepsis
Streptomyces
- Abundant soil organisms
- Mycelial
- Generate spores at ends of terminal hyphae
- Strict aerobes
- Nutritionally versatile
- Produce many antibiotics
- Antibiotics produced by Streptomyces include:
- Antibiotic droplets secreted by Streptomyces coelicolor
Corynebacteria
- Diverse group of Gram +, aerobic, non-motile club-shaped rods
- Animal pathogens, plant pathogens, and saprophytes
- Examples: Corynebacterium diptheriae
Corynebacterium Diptheriae
- Pathology of Diptheria:
- Upper respiratory tract illness
- Sore throat, low-grade fever, and adherent membrane of the tonsil(s), pharynx, and/or nose
- Spread by droplets or contact
- Toxigenic strains produce a toxin
- Toxin absorbs onto mucous membrane, causing destruction of epithelium and producing local inflammation
- Necrotic epithelium forms a greyish "pseudomembrane"
- Severe symptoms due to toxin action
- Lesions occur in kidney, heart, and nervous system
- 5-10% mortality even with treatment
- 4000 children die from diphtheria each year
Diphtheria Toxin
- Encoded by lysogenic phage
- A (catalytic) and B (receptor-binding) domains
- ADP-ribosylates elongation factor EF2, preventing protein synthesis
- Lethal dose for humans: 0.1 μg/kg
- Inactivated toxoid used as vaccine
- Antitoxin used for treatment
- Toxin used for Elek test
Diagnosis and Treatment of Diphtheria
- Gram stain or methylene blue show beaded bugs from swab
- Aerobic growth on most media; Loefflers serum media is semi-selective
- Elek test for toxigenicity:
- Antitoxin-soaked filter paper
- Perpendicular streaked samples
- Treatment: antitoxin and antibiotic (e.g., erythromycin)
- Vaccine: Diphtheria toxoid (DPT)
Gram-Positive Bacteria
- Firmicutes:
- Low GC gram-positive bacteria
- Examples: Lactic acid bacteria (Streptococcus, Lactobacillus), Staphylococcus, Listeria, Mycoplasma
- Actinobacteria:
- High GC gram-positive bacteria
- Examples: Streptomyces, Corynebacteria, Mycobacteria
Listeria
- Non-spore forming, gram-positive, non-motile rods
- Causes listeriosis
- Important cause of disease in humans and animals
- L. monocytogenes: short, gram-positive, non-spore forming rod; catalase positive, facultative anaerobe; tumbling motility at room temperature but not at 37°C
Listeriosis
- Two types:
- Perinatal:
- Early onset: intrauterine infection, sepsis, and death before birth
- Late onset: infected at birth, meningitis, and sepsis within 2-3 weeks
- Adult:
- Flu-like symptoms and gastro upset in immunocompetent individuals
- Meningo-encephalitis and bacteraemia in immunocompromised individuals
- Perinatal:
- Treatment: penicillin and gentamicin (gentamicin does not enter host cells)
- Source of infection: environment, animals, silage, infected humans
- Normal route of infection: gastrointestinal
- Outbreaks associated with dairy products, packaged meat, and fruit and vegetables
- Prevention: pasteurization of dairy foodstuffs and cooking of food
2011 Epidemic
- 33 deaths and 147 confirmed cases
- Listeria-contaminated cantaloupes killed 33 people
- Two Colorado farmers pleaded guilty to federal criminal charges
Pathogenesis of Listeria
- Infection leads to meningitis and sepsis
Streptomyces
- Abundant soil organisms
- Mycelial
- Generate spores at ends of terminal hyphae
- Strict aerobes
- Nutritionally versatile
- Produce many antibiotics
- Antibiotics produced by Streptomyces include:
- Antibiotic droplets secreted by Streptomyces coelicolor
Corynebacteria
- Diverse group of Gram +, aerobic, non-motile club-shaped rods
- Animal pathogens, plant pathogens, and saprophytes
- Examples: Corynebacterium diptheriae
Corynebacterium Diptheriae
- Pathology of Diptheria:
- Upper respiratory tract illness
- Sore throat, low-grade fever, and adherent membrane of the tonsil(s), pharynx, and/or nose
- Spread by droplets or contact
- Toxigenic strains produce a toxin
- Toxin absorbs onto mucous membrane, causing destruction of epithelium and producing local inflammation
- Necrotic epithelium forms a greyish "pseudomembrane"
- Severe symptoms due to toxin action
- Lesions occur in kidney, heart, and nervous system
- 5-10% mortality even with treatment
- 4000 children die from diphtheria each year
Diphtheria Toxin
- Encoded by lysogenic phage
- A (catalytic) and B (receptor-binding) domains
- ADP-ribosylates elongation factor EF2, preventing protein synthesis
- Lethal dose for humans: 0.1 μg/kg
- Inactivated toxoid used as vaccine
- Antitoxin used for treatment
- Toxin used for Elek test
Diagnosis and Treatment of Diphtheria
- Gram stain or methylene blue show beaded bugs from swab
- Aerobic growth on most media; Loefflers serum media is semi-selective
- Elek test for toxigenicity:
- Antitoxin-soaked filter paper
- Perpendicular streaked samples
- Treatment: antitoxin and antibiotic (e.g., erythromycin)
- Vaccine: Diphtheria toxoid (DPT)
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Description
Test your knowledge of bacteria classification, including Firmicutes, Actinobacteria, and more. Identify the characteristics and examples of different types of bacteria.
