Staphylococci

What virulence factors does aureus have to protect itself from neutrophil-mediated killing?

Enterotoxins
Toxin production in food (correct)
Antibody resistance
Capsule formation

Which type of organisms are Staphylococci?

Spiral
Rod-shaped
Bacilli
Spherical (correct)

What distinguishes Staphylococcal Food Poisoning from other foodborne illnesses regarding food taste and storage?

Causes bad taste in food
Requires refrigeration to prevent illness
Is heat-resistant during cooking
Has no effect on food taste (correct)

What is a major problem organism among Staphylococci according to the text?

Staphylococcus aureus (C) Signup and view all the answers

What is the primary action of Staphylococcal enterotoxins on the body?

Central Nervous System (CNS) effects (D) Signup and view all the answers

Why is antibiotic treatment deemed unnecessary for Staphylococcal Food Poisoning?

Rapid recovery without antibiotics (C) Signup and view all the answers

Which enzyme is hydrolyzed by Staphylococcus aureus according to the text?

Coagulase (D) Signup and view all the answers

Which of the following colors is associated with Staphylococcus aureus?

Yellow (B) Signup and view all the answers

Which predisposing factor increases the risk of Staphylococcal Food Poisoning?

Immunodeficiency diseases (B) Signup and view all the answers

How does Staphylococcus aureus develop resistance to antibiotics like penicillin?

By altering cell wall structure via PBP gene modification (C) Signup and view all the answers

What is a distinguishing characteristic of Staphylococcus epidermidis compared to S.aureus?

Mannitol fermentation (D) Signup and view all the answers

Which Staphylococcus species is resistant to Novobiocin?

S.epidermidis (C) Signup and view all the answers

What distinguishes Methicillin-resistant S. aureus (MRSA) from Penicillin-resistant strains?

Production of beta-lactamase enzyme (B) Signup and view all the answers

Why is S.epidermidis less susceptible to specific antibiotics compared to S.aureus according to the text?

<ul> <li>Novobiocin resistance (B)</li> </ul> Signup and view all the answers

What is the function of Coagulase, as described in the text?

Converts fibrinogen to fibrin (D) Signup and view all the answers

Which of the following best describes the role of Protein A in Staphylococcus aureus?

Inhibits antibody-mediated opsonization (B) Signup and view all the answers

What effect does Catalase have on hydrogen peroxide, according to the text?

Breaks it down to O2 and H2O (C) Signup and view all the answers

How does the Capsule or slime layer contribute to the virulence of Staphylococcus aureus?

Prevents phagocytosis (A) Signup and view all the answers

Which enzyme damages connective tissue according to the text?

Hyaluronidase (B) Signup and view all the answers

What is the primary function of the Cell wall components of Staphylococcus aureus?

Binds to exposed fibronectin in wounds (B) Signup and view all the answers

Which factor makes Staphylococcus aureus look less foreign and masks its harmfulness?

Protein A (B) Signup and view all the answers

What is the main difference between nosocomial and community-associated MRSA infections?

Nosocomial infections occur in healthcare settings, while community-associated infections occur outside of healthcare facilities. (C) Signup and view all the answers

Which of the following is NOT a risk factor for nosocomial MRSA infection?

Being a healthy person without any underlying conditions (A) Signup and view all the answers

Where did the first cases of Community-Associated MRSA (CA-MRSA) infections occur?

Detroit, Michigan among IV drug users (A) Signup and view all the answers

What are the typical manifestations of Staph or MRSA infections in the community?

Usually manifested as skin infections like pimples and boils (D) Signup and view all the answers

Who is more likely to get nosocomial MRSA infections?

Patients undergoing prolonged antimicrobial chemotherapy (D) Signup and view all the answers

Which population group was NOT mentioned as being at risk for Community-Associated MRSA?

Elderly individuals in nursing homes (A) Signup and view all the answers

What defines MRSA infection as 'community-associated'?

Infections acquired by persons not recently hospitalized or having medical procedures (A) Signup and view all the answers

Which of the following is NOT a risk factor for CA-MRSA infections?

Regular visit to the hospital (D) Signup and view all the answers

What is the primary mechanism through which MRSA becomes resistant to penicillin-derived antibiotics?

Production of PBP2a protein (B) Signup and view all the answers

Which of the following antibiotics is effective against some multi-drug resistant MRSA strains?

Linezolid (C) Signup and view all the answers

What is the role of vancomycin in treating MRSA infections?

It targets and disrupts the cell wall synthesis in MRSA (C) Signup and view all the answers

Which of the following is a risk factor for CA-MRSA infections according to the text?

Methicillin use (C) Signup and view all the answers

What makes penicillin-derived antibiotics inactive in the presence of MRSA?

Hydrolysis of the β-lactam ring by zyme β-lactamases (A) Signup and view all the answers

Why are vancomycin-resistant MRSA strains a concern in healthcare settings?

They are associated with higher mortality rates (A) Signup and view all the answers

Which alternative antibiotics are mentioned in the text for treating MRSA infections?

Oxazolidinones and streptogrammins (A) Signup and view all the answers

What is the significance of PBP2a protein in methicillin-resistant S. aureus (MRSA)?

It alters the function of penicillin-binding proteins (PBP's) (D) Signup and view all the answers

Why are permanent indwelling catheters considered a risk factor for CA-MRSA infections?

They provide a direct passage for MRSA to enter the body (C) Signup and view all the answers