Podcast
Questions and Answers
What is the principle method used for detection of Spiroplasma?
What is the principle method used for detection of Spiroplasma?
- Culture techniques
- Molecular techniques such as PCR (correct)
- Gram staining
- Biochemical tests
What is the recommended treatment for Spiroplasma infections in the UK?
What is the recommended treatment for Spiroplasma infections in the UK?
- Doxycycline and azithromycin (correct)
- Erythromycin and tetracycline
- Moxifloxacin and streptomycin
- Ciprofloxacin and amoxicillin
What type of bacteria is Spiroplasma?
What type of bacteria is Spiroplasma?
- Mollicutes (correct)
- Firmicutes
- Actinobacteria
- Gram negative bacteria
What is a characteristic of Lactic Acid Bacteria?
What is a characteristic of Lactic Acid Bacteria?
What is the byproduct of fermentation in Lactic Acid Bacteria?
What is the byproduct of fermentation in Lactic Acid Bacteria?
What is a unique feature of Lactic Acid Bacteria?
What is a unique feature of Lactic Acid Bacteria?
What is a requirement for the growth of Lactic Acid Bacteria?
What is a requirement for the growth of Lactic Acid Bacteria?
What is a characteristic of Spiroplasma citrii?
What is a characteristic of Spiroplasma citrii?
What is the characteristic of Streptococcus cells in terms of division?
What is the characteristic of Streptococcus cells in terms of division?
What is the primary source of catalase for Streptococcus growth?
What is the primary source of catalase for Streptococcus growth?
Which of the following is NOT a characteristic of Streptococcus?
Which of the following is NOT a characteristic of Streptococcus?
What is the basis of Lancefield grouping of Streptococci?
What is the basis of Lancefield grouping of Streptococci?
Which group of Streptococci is associated with the intestinal tract of humans and animals?
Which group of Streptococci is associated with the intestinal tract of humans and animals?
What is the result of β-hemolysis on blood agar?
What is the result of β-hemolysis on blood agar?
What is the name of the scientist who developed the Lancefield grouping system?
What is the name of the scientist who developed the Lancefield grouping system?
Which of the following is a type of LAB that is commonly used as a probiotic?
Which of the following is a type of LAB that is commonly used as a probiotic?
What is the percentage of healthy people who may be carriers of group A, beta hemolytic Streps in their throat and nasopharynx?
What is the percentage of healthy people who may be carriers of group A, beta hemolytic Streps in their throat and nasopharynx?
What is the name of the toxin encoded by a phage that causes scarlet fever?
What is the name of the toxin encoded by a phage that causes scarlet fever?
What is the name of the disease that occurs in a small percentage of individuals, 2-3 weeks after an untreated pharyngeal infection caused by a β hemolytic group A Strep?
What is the name of the disease that occurs in a small percentage of individuals, 2-3 weeks after an untreated pharyngeal infection caused by a β hemolytic group A Strep?
What is the name of the test used to identify group A strep?
What is the name of the test used to identify group A strep?
What is the name of the phage that encodes the superantigen toxin?
What is the name of the phage that encodes the superantigen toxin?
How many antigenically distinct toxins are there in group A strep?
How many antigenically distinct toxins are there in group A strep?
What is the name of the disease that is characterized by small vesicles on the skin forming a thin amber crust?
What is the name of the disease that is characterized by small vesicles on the skin forming a thin amber crust?
What is the name of the heart condition that can occur as a result of rheumatic fever?
What is the name of the heart condition that can occur as a result of rheumatic fever?
What is the primary mechanism behind glomerulonephritis following a group A Strep infection?
What is the primary mechanism behind glomerulonephritis following a group A Strep infection?
What is the primary reservoir for Group B Streptococci?
What is the primary reservoir for Group B Streptococci?
What is a significant complication of untreated Group B Streptococcal infections in newborns?
What is a significant complication of untreated Group B Streptococcal infections in newborns?
What is the name of the test used to identify Streptococci?
What is the name of the test used to identify Streptococci?
What is the primary concern associated with Group D Streptococci?
What is the primary concern associated with Group D Streptococci?
What is the characteristic of Viridans Streptococci that makes them significant causes of bacterial endocarditis?
What is the characteristic of Viridans Streptococci that makes them significant causes of bacterial endocarditis?
What is the name of the Streptococcal species that causes dental caries?
What is the name of the Streptococcal species that causes dental caries?
What is the characteristic of non-suppurative diseases caused by Group A Streptococcal infections?
What is the characteristic of non-suppurative diseases caused by Group A Streptococcal infections?
What is the characteristic shape of Streptococcus pneumoniae?
What is the characteristic shape of Streptococcus pneumoniae?
What is the function of the capsule in Streptococcus pneumoniae?
What is the function of the capsule in Streptococcus pneumoniae?
How many types of Streptococcus pneumoniae are there based on the antigenicity of the capsular polysaccharide?
How many types of Streptococcus pneumoniae are there based on the antigenicity of the capsular polysaccharide?
What is the percentage of Streptococcus pneumoniae infections that lead to bacteremia?
What is the percentage of Streptococcus pneumoniae infections that lead to bacteremia?
What is the typical morphology of Streptococcus pneumoniae colonies on blood agar?
What is the typical morphology of Streptococcus pneumoniae colonies on blood agar?
What is the principle of the quellung test?
What is the principle of the quellung test?
What is the typical treatment for Streptococcus pneumoniae meningitis?
What is the typical treatment for Streptococcus pneumoniae meningitis?
What is the approximate annual mortality rate due to Streptococcus pneumoniae infections?
What is the approximate annual mortality rate due to Streptococcus pneumoniae infections?
Streptococcus divides in multiple planes.
Streptococcus divides in multiple planes.
Lactic acid bacteria are grouped based on their morphology.
Lactic acid bacteria are grouped based on their morphology.
Homofermentative lactic acid bacteria produce lactic acid and CO2 as byproducts.
Homofermentative lactic acid bacteria produce lactic acid and CO2 as byproducts.
Leuconostoc is a heterofermentative lactic acid bacterium.
Leuconostoc is a heterofermentative lactic acid bacterium.
Lactobacillus bulgaricus is used in the production of Swiss cheese.
Lactobacillus bulgaricus is used in the production of Swiss cheese.
Streptococcus thermophilus is used in the production of sour cream and ripe cream.
Streptococcus thermophilus is used in the production of sour cream and ripe cream.
Lactic acid bacteria are used in the production of starter cultures.
Lactic acid bacteria are used in the production of starter cultures.
Pediococcus forms spheres in chains.
Pediococcus forms spheres in chains.
Mycoplasma genitalium has a genome size of 816 kbp.
Mycoplasma genitalium has a genome size of 816 kbp.
Mycoplasma pneumoniae is a strict anaerobe.
Mycoplasma pneumoniae is a strict anaerobe.
The human genome contains approximately 5440 kbp of DNA.
The human genome contains approximately 5440 kbp of DNA.
Ureaplasma is a type of Mycoplasma that requires cholesterol and urea for growth.
Ureaplasma is a type of Mycoplasma that requires cholesterol and urea for growth.
Acholeplasma is a type of Mycoplasma that is a strict anaerobe.
Acholeplasma is a type of Mycoplasma that is a strict anaerobe.
Spiroplasma is a type of Mycoplasma that causes disease in humans.
Spiroplasma is a type of Mycoplasma that causes disease in humans.
Mycoplasma pneumoniae is typically transmitted through contaminated food and water.
Mycoplasma pneumoniae is typically transmitted through contaminated food and water.
Primary atypical pneumonia caused by Mycoplasma pneumoniae is typically seen in individuals over 50 years old.
Primary atypical pneumonia caused by Mycoplasma pneumoniae is typically seen in individuals over 50 years old.
M.pneumoniae can be grown in media containing serum without penicillin.
M.pneumoniae can be grown in media containing serum without penicillin.
The bacterium Mycoplasma pneumoniae produces oxygen peroxide.
The bacterium Mycoplasma pneumoniae produces oxygen peroxide.
Ureaplasma urealyticum is a type of genital Mycoplasma that causes pneumonia.
Ureaplasma urealyticum is a type of genital Mycoplasma that causes pneumonia.
Erythromycin is effective against Legionella infections.
Erythromycin is effective against Legionella infections.
Mycoplasma pneumoniae infections can be diagnosed using serological tests such as PCR.
Mycoplasma pneumoniae infections can be diagnosed using serological tests such as PCR.
Mycoplasma genitalium can cause infertility in women.
Mycoplasma genitalium can cause infertility in women.
Mycoplasma pneumoniae is resistant to antibiotics that act on the cell membrane.
Mycoplasma pneumoniae is resistant to antibiotics that act on the cell membrane.
M.hominis can cause pneumonia in adults.
M.hominis can cause pneumonia in adults.
Streptococcus lactis is a type of bacteria that requires complex media for growth.
Streptococcus lactis is a type of bacteria that requires complex media for growth.
Leuconostoc citrovorum is a type of LAB that is commonly used as a probiotic.
Leuconostoc citrovorum is a type of LAB that is commonly used as a probiotic.
Streptococcus durans is a type of bacteria that can make haem group of cytochromes and catalase.
Streptococcus durans is a type of bacteria that can make haem group of cytochromes and catalase.
Lactic Acid Bacteria are able to divide in multiple planes, forming clusters.
Lactic Acid Bacteria are able to divide in multiple planes, forming clusters.
Streptococcus is a type of bacteria that requires blood agar as a primary source of catalase.
Streptococcus is a type of bacteria that requires blood agar as a primary source of catalase.
Enterococcus faecalis is a type of LAB that is commonly used in the production of soft Italian cheeses.
Enterococcus faecalis is a type of LAB that is commonly used in the production of soft Italian cheeses.
Rebecca Lancefield is the scientist who developed the Lancefield grouping system for Streptococci.
Rebecca Lancefield is the scientist who developed the Lancefield grouping system for Streptococci.
Group D Streptococci are typically found in the intestinal tract of humans and animals.
Group D Streptococci are typically found in the intestinal tract of humans and animals.
Streptococcus pyogenes is a type of α-hemolytic bacteria.
Streptococcus pyogenes is a type of α-hemolytic bacteria.
The Bacitracin sensitivity test is used to identify Group B Streptococci.
The Bacitracin sensitivity test is used to identify Group B Streptococci.
Necrotizing fasciitis is a non-suppurative disease caused by Group A Streptococcal infections.
Necrotizing fasciitis is a non-suppurative disease caused by Group A Streptococcal infections.
Rheumatic fever is a result of Strep sore throat caused by a pyrogenic toxin-producing organism.
Rheumatic fever is a result of Strep sore throat caused by a pyrogenic toxin-producing organism.
There are five antigenically distinct toxins in Group A Strep.
There are five antigenically distinct toxins in Group A Strep.
Scarlet fever is a result of Strep sore throat caused by a non-pyrogenic toxin-producing organism.
Scarlet fever is a result of Strep sore throat caused by a non-pyrogenic toxin-producing organism.
Streptococcal impetigo is a disease that occurs in a small percentage of individuals, 2-3 weeks after an untreated pharyngeal infection.
Streptococcal impetigo is a disease that occurs in a small percentage of individuals, 2-3 weeks after an untreated pharyngeal infection.
Rheumatic heart disease is a rare condition in developing countries.
Rheumatic heart disease is a rare condition in developing countries.
Study Notes
Spiroplasma
- Detection relies on molecular techniques (PCR) due to difficulty in culturing
- Recommended treatment: doxycycline pretreatment then azithromycin (or moxifloxacin)
- Antibiotic resistance is high
The Lactic Acid Bacteria
- Gram-positive bacteria
- Includes Streptococcus, Lactobacillus, and Enterococcus
- Produce lactic acid as a product of fermentation
- Non-spore forming, non-motile, and lack cytochromes
- Obtain energy by substrate level phosphorylation and not by electron transport and oxidative phosphorylation
- Normally obtain energy only from sugars
- Limited biosynthetic capability and require many vitamins, amino acids, purines, and pyrimidines
- Aerotolerant anaerobes, growth not affected by presence of air
- Tolerant of acid, and can produce and tolerate high concentrations of lactic acid
- Found in cultured buttermilk, sour cream, cottage cheese, and cheeses
Streptococcus
- Spherical cells divide only in one plane and form chains
- Require complex media for growth
- Unable to make haem group of cytochromes or catalase
- Grown on blood agar (good source of catalase)
- Grouping of Streptococci:
- Hemolysis: β (complete hemolysis), α (incomplete hemolysis), and γ (no hemolysis)
- Antigenically/Serologically (Lancefield Groups): A, B, C, D, etc. based on specific carbohydrate antigen extracted by heating cells up to 150°C
- Streptococcus pyogenes (Group A Strep):
- β-hemolytic
- Causes many streptococcal diseases in humans
- Antigenicity of M-proteins in the cell wall provides sub-classification into over 100 sub-serotypes
- Found in 5-30% of healthy people as carriers in their throat and nasopharynx
- Bacitracin sensitivity test
- Streptococcal diseases:
- Strep Throat
- Impetigo
- Scarlet Fever: caused by a pyrogenic toxin-producing organism, symptoms include fever, toxic shock, and erythematous rash
- Cellulitis: infection of the deep layers of the skin
- Necrotizing fasciitis: highly invasive, toxigenic, infection of soft tissues and fascia
- Non-suppurative diseases:
- Rheumatic fever: occurs in a small percentage of individuals, 2-3 weeks after an untreated pharyngeal infection
- Glomerulonephritis: most cases occur about a week after group A Strep infection, leads to loss of protein through kidneys and hypertension
- Other Streptococci:
- Group B Streptococci: S. agalactiae, found in vaginal flora of 25% of women, may cause serious infections in newborns
- Group D Streptococci: faecal flora, enterococci, cause urinary and wound infections, and are a major problem of vancomycin-resistance
- α-hemolytic Streptococci: Viridans group, includes many species that are normal inhabitants of throat and nasopharynx of humans
- Streptococcus pneumoniae:
- Lancet-shaped organism, usually arranged in pairs
- Virulent organisms are encapsulated, resist phagocytosis
- Subdivided into 90 types on the basis of antigenicity of capsular polysaccharide
- Found in the normal commensal of the upper respiratory tract
- Causes streptococcal pneumonia, accounts for about one million deaths per annum worldwide, and is the second most common cause of meningitis in adults
Lactic Acid Bacteria (LAB)
- LAB are used to eliminate competition in selective media
- They can be grouped by their fermentation patterns:
- Homofermentative: produces a single fermentation product (lactic acid) using the Embden-Meyerhof (glycolytic) pathway
- Heterofermentative: produces lactic acid and other products (CO2 and ethanol) using the pentose phosphate pathway
- Examples of LAB and their products:
- Lactobacillus bulgaricus: Bulgarian buttermilk, yoghurt, kefir, koumiss, Swiss, Emmental, and Italian cheeses
- Lactobacillus acidophilus: acidophilus buttermilk, Emmental, Cheddar, and Italian cheeses
- Streptococcus thermophilus: acid, yoghurt, and Italian cheeses
- Streptococcus diacetilactis: acid, sour cream, ripe cream, butter, cheese, buttermilk, and starter cultures
Mycoplasmas
- Mycoplasma genitalium has the smallest known genome of any self-replicating organism (580 kbp encoding 472 genes)
- Mycoplasma pneumoniae has a larger genome (816 kbp containing 679 putative genes)
- During evolution, mycoplasmas have undergone multiple reductions in genome size and have an unusually high rate of evolution
- Mollicutes (Mycoplasma-like organisms) are:
- Mycoplasmas: require cholesterol, parasitic on animal mucous membranes, facultative anaerobes, and over 60 species recognized
- Ureaplasma (T-Strain Mycoplasmas): microaerophilic, require cholesterol and urea for growth, and may be associated with nongonococcal urethritis
- Acholeplasma: widely distributed animal parasites, facultative aerobes, able to grow in the absence of sterols
- Anaeroplasma: strict anaerobes, inhabit bovine or ovine rumen
- Spiroplasma: helical, motile, parasites on arthropods and plants, but a few cause disease in animals
Mycoplasma pneumoniae
- Causes primary atypical pneumonia in humans (PAP or "walking pneumonia")
- Affects individuals 5-20 years old
- Symptoms range from mild flu-like disease to severe pneumonia with fever, chills, and malaise
- Protracted course with gradual resolution (month)
- Transmitted through close personal contact via respiratory droplets
- May be a prevalence of infections occurring in autumn
- The bacterium settles on a respiratory epithelial cell, binds to it, and produces hydrogen peroxide, which is responsible for much of the initial cell disruption in the respiratory tract
Diagnosis and Treatment of Mycoplasma pneumoniae
- Diagnosis:
- Clinical symptoms
- Serological tests (Serum cold agglutination, Complement fixation test, ELISAs)
- DNA test (PCR) is replacing serological tests
- Microbiological detection: not that useful because culture is slow
- Treatment:
- Erythromycin, doxycycline (not for children), azithromycin, and levofoxacin
- Erythromycin is often used as it is also effective against legionella
GENITAL MYCOPLASMAS
- Mycoplasma genitalium:
- Causes non-gonococcal (non-chlamydial) urethritis (NGU)
- May be associated with infertility in men and women
- Transmitted by direct venereal contact and vertically transmitted from mother to offspring
- Mycoplasma hominis and Ureaplasma urealyticum:
- 50% of normal adults have antibodies
- Causes of non-gonococcal urethritis (NGU)
- May be associated with infertility in men and women
Streptococcus
- Spherical cells divide only in one plane and form chains
- Require complex media for growth
- Unable to make haem group of cytochromes or catalase
- Grown on blood agar (good source of catalase)
Grouping of Streptococci
- Hemolysis:
- β - complete hemolysis -> clear zone
- α - incomplete hemolysis of red blood cells -> greenish-brown zone
- γ - hemolytic - no hemolysis
- Antigenically/Serologically:
- Lancefield Groups of β-hemolytic Streps (A, B, C, D…H and K-W)
- Group A - S. pyogenes
- Group B - Cattle and humans (e.g. S. agalactiae)
- Group D - Intestinal tract of man and animals (Enterococcus)
Group A Strep
- β hemolytic
- Causes many of the streptococcal diseases of humans
- Antigenicity of M-proteins in the cell wall provides sub-classification of group A into over 100 sub-serotypes
- Habitat: 5-30% of healthy people may be carriers of group A, beta hemolytic Streps in their throat and nasopharynx
Streptococcal Diseases
- Strep throat
- Impetigo
- Scarlet fever
- Cellulitis
- Necrotizing fasciitis
- Non-suppurative diseases:
- Rheumatic fever
- Rheumatic heart disease
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Description
This quiz covers the microbiology of Spiroplasma and Lactic Acid Bacteria, including their characteristics, detection methods, and treatment options.