Cocci Flashcards
What is the characteristic shape of Staphylococcus aureus?
Grape-like clusters
Where is Staphylococcus aureus commonly found in the body?
Nose, groin, perineum (normal flora)
What is the primary mode of transmission for Staphylococcus aureus?
Direct contact
Which enzyme is a virulence factor of Staphylococcus aureus?
Coagulase
What is the function of Protein A in Staphylococcus aureus?
Virulence factor that binds antibodies
Name a toxin produced by Staphylococcus aureus involved in skin conditions.
Exfoliatin/epidermolytic toxin
What is TSST in relation to Staphylococcus aureus?
Toxic Shock Syndrome Toxin
List some suppurative diseases caused by Staphylococcus aureus.
- Folliculitis
- Boils/Furuncles
- Carbuncles
- Impetigo
- Bacteraemia
- Infective endocarditis
- Septic arthritis
- Osteomyelitis
- Pneumonia
- Surgical wound infection
What syndrome is caused by exfoliatin from Staphylococcus aureus?
Scalded skin syndrome
What is the treatment for Staphylococcal food poisoning?
Cloxacillin, erythromycin, cephalosporin
What is the treatment for Methicillin Resistant Staphylococcus Aureus (MRSA)?
Vancomycin
What laboratory test result indicates Staphylococcus aureus?
Catalase test +ve (active bubbling)
What color do Staphylococcus aureus colonies appear on blood agar?
Golden yellow
What is the characteristic shape of Staphylococcus epidermidis?
Grape-like clusters
Where does Staphylococcus epidermidis primarily colonize?
Skin superficials
What is a major virulence factor of Staphylococcus epidermidis?
Biofilm (extracellular slime)
List some infections related to the use of medical devices caused by Staphylococcus epidermidis.
- Catheter-related bloodstream infection
- Prosthetic valve endocarditis
- Infection of prosthetic joints
- Catheter-related UTI
What is the treatment for infections caused by Staphylococcus epidermidis?
Removal of infected devices
What is the novobiocin sensitivity of Staphylococcus epidermidis?
Sensitive
What is the characteristic shape of Staphylococcus saprophyticus?
Grape-like clusters
Where does Staphylococcus saprophyticus commonly colonize?
Genital mucosa & distal urethra
What type of infection is commonly associated with Staphylococcus saprophyticus?
UTI particularly in sexually active young women
What is the novobiocin sensitivity of Staphylococcus saprophyticus?
Resistant
What is a recommended preventative measure for UTIs caused by Staphylococcus saprophyticus?
Empty bladder after intercourse
What test results indicate Staphylococcus saprophyticus?
Catalase test +ve (active bubbling), Coagulase test -ve
What is the scientific name for Group A Streptococcus?
Streptococcus pyogenes
Commonly associated with several diseases including pharyngitis and scarlet fever.
What are the primary sources of transmission for Streptococcus pyogenes?
Skin & respiratory tract through respiratory droplets and direct contact
This includes close contact with infected individuals.
Name a key virulence factor of Streptococcus pyogenes.
M-protein
This factor is anti-phagocytic, helping the bacteria evade the immune system.
What disease is caused by the erythrogenic toxin of Streptococcus pyogenes?
Scarlet fever
The toxin is responsible for the characteristic rash associated with the disease.
List two diseases caused by Streptococcus pyogenes.
- Pharyngitis
- Necrotizing fasciitis
Pharyngitis can lead to complications such as rheumatic fever.
What is the first-line treatment for infections caused by Streptococcus pyogenes?
Penicillin
Erythromycin is an alternative for patients allergic to penicillin.
What is the characteristic laboratory test result for Streptococcus pyogenes?
ß-haemolysis
This is a key identifier in laboratory settings.
What is the scientific name for Group B Streptococcus?
Streptococcus agalactiae
Commonly found in the genital tract and can affect newborns.
How is Streptococcus agalactiae transmitted?
From the birth canal and direct contact between babies in nursery
This can lead to serious infections in neonates.
What is one virulence factor of Streptococcus pneumoniae?
Polysaccharide capsule
This capsule protects the organism from phagocytosis.
List two diseases caused by Streptococcus pneumoniae.
- Pneumonia
- Meningitis
Pneumococcal pneumonia is a common infection, particularly in young children and the elderly.
What is the first-line treatment for infections caused by Streptococcus pneumoniae?
Penicillin/ampicillin + gentamicin
Resistance to penicillin is increasing, thus alternatives may be needed.
What is a key characteristic of viridans streptococci?
Optochin resistant
This group is often found in the oral cavity and respiratory tract.
What disease is commonly associated with viridans streptococci?
Infective endocarditis
These bacteria can enter the bloodstream and affect heart valves.
What is the scientific name for Group D Streptococcus?
Enterococci
Often found in the intestine and can lead to infections in compromised patients.
How is Enterococci typically acquired?
Endogenously acquired and through cross-infection in hospitalized patients
This highlights the importance of hygiene in healthcare settings.
What is a notable characteristic of Enterococci in laboratory tests?
Bile aesculin positive
This is a key feature for differentiating Enterococci from other bacteria.
True or False: Streptococcus pneumoniae is catalase positive.
False
Streptococcus pneumoniae is catalase negative.
Fill in the blank: The treatment for neonatal infections caused by Group B Streptococcus includes _______.
Penicillin/ampicillin + gentamicin
Early treatment is crucial for the health of newborns.
