62 Questions
Where is microbiota found?
All of the above
Which region of the skin is preferred by S. aureus and S. pyogenes because they can be less acidic? AKA MORE ALKALINE
All of the above
What type of bacteria grows in sebaceous glands and can metabolize sebum?
Propionibacterium acnes
What gene does Methicillin Resistant Staphylococcus aureus (MRSA) contain?
mecA gene
In which type of environment is persistent moisture under dressings a good environment for pathogens?
Moist environment
What type of bacteria is associated with death of healthy individuals, such as athletes?
Community acquired MRSA
What does the SCCmec IV staphylococcal chromosomal cassette of CA-MRSA contain that encode an arginine metabolic cassette?
ACME genes
What does the metabolism of arginine produce as a byproduct?
Ammonia
What type of bacteria is Gram-positive cocci in grape-like clusters and catalase-positive, coagulase-positive and beta-hemolytic on blood agar plates?
Staphylococcus aureus
What type of bacteria is Gram-positive cocci in chains, beta hemolytic on blood agar plates, and catalase negative?
Group A Streptococci
Which type of MRSA is often resistant to other antibiotics and is commonly found in hospitals?
HA-MRSA
What does the SCCmec IV staphylococcal chromosomal cassette of CA-MRSA contain that encodes an arginine metabolic cassette?
ACME genes
What is the byproduct produced when arginine is metabolized?
Ammonia, which neutralizes the skin pH allowing for better colonization.
What is the main factor that causes microbiota to vary from site to site?
Differences in moisture and presence or absence of sebaceous glands.
The use of arginine in the metabolic pathway by CA-MRSA will deplete it form the environment. What are the two things that arginine is needed for that decrease due to colonized CA-MRSA?
Nitroic Oxide and Polyamines
Which bacterium is the most common cause of boils?
Staphylococcus aureus
Boils/abcesses caused by S. aureus do not usually cause infection unless it has gone ______?
Through broken skin
What are the virulence factors associated with boils?
Fibronectin binding proteins, protein A and coagulase
What is the hallmark of S. aureus boils?
High pus production
What is the characteristic of cellulitis involving the epidermis and upper dermis?
Superficial involvement
What type of bacteria is commonly associated with deeper involvement of cellulitis?
Streptococcus spp. and Staphylococcus aureus
What is the microorganism responsible for cellulitis involving the epidermis and upper dermis?
Beta-hemolytic streptococcus such as S. pyogenes
What is the characteristic of cellulitis involving superficial involvement?
More acute onset, raised edge
What type of bacteria is commonly associated with deeper involvement of cellulitis?
Slower presentation, subtler edge
Which bacterial infection is characterized by redness and warmth of the skin with a defined edge that is palpable? AND IS CAUSED BY S. PYOGENES
Erysipelas
Which bacterial infection spreads in a plane parallel to the skin and spares underlying muscle?
Fasciitis
Which bacterial infection can be life-threatening and often produces pain out of proportion to the visible redness?
Necrotizing fasciitis
Which bacterial infection is commonly found in children, highly contagious, and starts with one or more itchy sores?
Impetigo
Which bacterial infection involves the epidermis and the upper layer of dermis, and is often seen on the legs of adults?
Erysipelas
Which bacterial infection requires antibiotics and surgical debridement for treatment?
Necrotizing fasciitis
Which bacterial infection is characterized by honey-colored crusts and heals without scarring, unless scratching cuts deep into the skin?
Impetigo
Which bacterial infection can produce gas bubbles in tissue and often accompanied by fever and evidence of toxic appearance?
Necrotizing fasciitis
Which bacterial infection is caused by Staphylococcus aureus and Streptococcus pyogenes and is highly contagious in children?
Impetigo
Which topical antibiotics are commonly used for the treatment of impetigo?
Mupirocin and retapamulin
What is the most common causative agent of necrotizing fasciitis, also known as 'flesh-eating bacteria'?
Streptococcus pyogenes (GAS)
Which condition is characterized by black necrotic tissue and anaerobic conditions?
Gas Gangrene
Which bacterium is commonly associated with Gas Gangrene?
Clostridium perfringens, GRAM POSITIVE SPORE-FORMER
Which bacterial infection is characterized by localized blisters to exfoliation of over 90% body surface?
Staphylococcal Scalded Skin Syndrome
Which bacterium is the causative agent of Staphylococcal Scalded Skin Syndrome?
Staphylococcus aureus
Which condition is characterized by purulent (pus filled) infection of muscle?
Myositis/pyomyositis
Which bacteria are most commonly associated with Myositis/pyomyositis?
Staphylococcus aureus
Which features can be present if the bacterium causing Myositis/pyomyositis is a toxin-producer?
Fever, low blood pressure, and organ malfunction
Which condition is characterized by reduced blood flow, nerve damage, and potentially more circulating sugars in the blood and tissues?
Diabetic foot wounds
Which bacterial infection is characterized by fever, malaise, lethargy, and rash on the head and neck which spreads to localized blisters?
Staphylococcal Scalded Skin Syndrome
Which bacterium is the causative agent of Staphylococcal Scalded Skin Syndrome?
Staphylococcus aureus
Which bacterial infection is a disease of neonates and children? Neonates can get from carrier mothers before GI tract flora is established, usually follows URT, inner ear infection or conjunctive itis in children
Staphylococcal Scalded Skin Syndrome
Which bacterium is the major causative agent of cellulitis after an animal bite?
Pasteurella Multocida
What is the largest spirochete and the causative agent of Lyme disease?
Borrellia burgdorferi
What is the best prevention for Lyme disease?
Early removal of ticks
Which bacterium is a gram negative coccobacilli and can cause necrotizing fasciitis, osteomyelitis, and septic arthritis?
Pasteurella Multocida
Which bacterium is transmitted by the deer tick and can cause a distinctive bullseye rash?
Borrellia burgdorferi
Which bacterium can cause septic arthritis in adults?
S. aureus and S. pyogenes
Which bacterial infection can produce early symptoms of mild-flu-like symptoms, secondary stage associated with neurological and cardiac abnormalities and late stage associated with the manifestation of arthritis?
Borrellia burgdorferi
What is the common cause of septic arthritis in children?
Haemophilus influenzae and Group B streptococci
What is the characteristic rash of Lyme disease called?
Erythema migrans
What is the recommended antibiotic treatment for Lyme disease?
Amoxicillin
What is septic arthritis?
An infection of a joint following surgery or sepsis
Which bacterial infection can produce papular or pustular lesions in disseminated disease?
Neisseria gonorrhoeae
Which bacterial infection can cause dissemination to the skin during bacteremia?
Neisseria meningitidis
Which bacterial infection can produce metastatic lesions in the skin and other body sites in cases of endocarditis?
Endocarditis
Which bacterium is responsible for causing pneumonia and meningitis in children, especially serotype B (Hib)?
Haemophilus influenzae
Which serotype of Haemophilus influenzae is particularly associated with pneumonia and meningitis in children?
Group B streptococci (Streptococcus agalactiae)
Study Notes
Microbiota Locations
- Microbiota are found in sebaceous glands, skin, and other body sites
Bacteria Characteristics
- S. aureus and S. pyogenes prefer the skin region with higher pH (alkalinity)
- Propionibacterium grows in sebaceous glands and can metabolize sebum
- Methicillin Resistant Staphylococcus aureus (MRSA) contains the mecA gene
- S. aureus is Gram-positive, catalase-positive, coagulase-positive, and beta-hemolytic on blood agar plates
- S. pyogenes is Gram-positive, catalase-negative, and beta-hemolytic on blood agar plates
CA-MRSA Characteristics
- CA-MRSA contains the SCCmec IV staphylococcal chromosomal cassette
- The cassette encodes an arginine metabolic cassette
- Arginine metabolism produces ammonia as a byproduct
- CA-MRSA depletes arginine from the environment, decreasing its availability for the host's immune system
- Arginine is needed for the immune system to function properly and for wound healing
Bacterial Infections
- S. aureus is the most common cause of boils
- Boils caused by S. aureus do not usually cause infection unless they have gone systemic
- Virulence factors associated with boils include catalase, coagulase, and beta-hemolysin
- The hallmark of S. aureus boils is the formation of abscesses
- Cellulitis involving the epidermis and upper dermis is characterized by redness, warmth, and a defined edge
- S. pyogenes is commonly associated with superficial cellulitis
- Cellulitis involving deeper tissues is commonly associated with S. aureus
- Erysipelas is a bacterial infection characterized by redness and warmth of the skin with a defined edge
- Necrotizing fasciitis is a life-threatening infection that can produce pain out of proportion to the visible redness
- Impetigo is a contagious bacterial infection characterized by honey-colored crusts and heals without scarring
- Gas gangrene is a bacterial infection characterized by gas bubbles in tissue and is often accompanied by fever and evidence of toxic appearance
Bacterial Infections (continued)
- Staphylococcal Scalded Skin Syndrome is a bacterial infection characterized by localized blisters to exfoliation of over 90% body surface
- Clostridium perfringens is the causative agent of Gas Gangrene
- Myositis/pyomyositis is a bacterial infection characterized by purulent infection of muscle
- Toxin-producing bacteria can cause Myositis/pyomyositis
- Diabetic patients are at risk of developing Myositis/pyomyositis
- Staphylococcus aureus is the causative agent of Staphylococcal Scalded Skin Syndrome
- Streptococcus pyogenes is a causative agent of cellulitis
- Pasturella multocida is the major causative agent of cellulitis after an animal bite
- Borrelia burgdorferi is the largest spirochete and the causative agent of Lyme disease
- The best prevention for Lyme disease is the use of protective clothing and tick repellents
- Lyme disease can produce early symptoms of mild-flu-like symptoms, secondary stage associated with neurological and cardiac abnormalities, and late stage associated with arthritis
- Haemophilus influenzae is the common cause of septic arthritis in children
- The characteristic rash of Lyme disease is the erythema migrans (bullseye rash)
- Doxycycline is the recommended antibiotic treatment for Lyme disease
- Septic arthritis is a bacterial infection characterized by joint inflammation and pus accumulation
Test your knowledge on the microbiota found on the skin surface and its variations across different sites. Learn about the factors that affect colonization by pathogens and the impact of moisture on skin health.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free