Staphylococcus Species Vocabulary Flashcards

Vocabulary practice flashcards generated from lecture notes on Staphylococcus species, covering key characteristics, structural virulence factors, toxins, enzymes, clinical diseases, and diagnostic features.

Staphylococcus aureus

Main pathogenic staphylococcal species found primarily on human mucous membranes that tests positive for coagulase.

Staphylococcus epidermidis

Usually harmless skin bacterium found in normal flora carried by $99\%$ of the population; an opportunistic coagulase-negative pathogen typically associated with indwelling catheters and prosthetic heart valves.

Staphylococcus saprophyticus

Coagulase-negative staphylococcal species that colonizes the urinary tract and causes urinary tract infections in young, sexually active females.

PBP2a

Novel penicillin-binding protein produced by Staphylococcus aureus that confers resistance to methicillin and related penicillins/cephalosporins.

Slime layer

Water-soluble film of monosaccharides, proteins, and small peptides that facilitates adherence of staphylococci to foreign bodies.

Protein A

Major cell wall protein of Staphylococcus aureus that binds the Fc portion of IgG1, IgG2, and IgG4 at the complement-binding site, inhibiting antibody-mediated immune clearance and complement activation.

Peptidoglycan (Staphylococcus aureus)

Cell wall component that provides osmotic stability, stimulates endogenous pyrogen production, acts as a leukocyte chemoattractant for abscess formation, and inhibits phagocytosis.

Teichoic acid

Species-specific cell wall component bound to NAM residues or cytoplasmic membrane lipids that binds to fibronectin and elicits specific antibody responses when bound to peptidoglycan.

Alpha toxin

Staphylococcus aureus cytotoxin that disrupts smooth muscle in blood vessels, causing rapid efflux of K and influx of Na/Ca, leading to osmotic swelling and cell lysis.

Beta toxin

Staphylococcus aureus cytotoxin (sphingomyelinase C) that catalyzes the hydrolysis of membrane phospholipids, leading to cell lysis.

Delta toxin

Staphylococcus aureus cytotoxin that affects erythrocytes by disrupting cellular membranes through a detergent-like action.

Exfoliative toxins (ETA, ETB)

Serine proteases produced by Staphylococcus aureus that split intercellular bridges in the stratum granulosum epidermis without causing cytolysis or inflammation.

Enterotoxin A

Staphylococcus aureus toxin most commonly associated with food poisoning intoxication; it is heat stable at $100\,^\circ\text{C}$ for $30\,\text{min}$ and resistant to gastric and jejunal enzymes.

Enterotoxin B

Staphylococcus aureus enterotoxin responsible for staphylococcal pseudomembranous enterocolitis.

Toxic Shock Syndrome Toxin-1 (TSST-1)

Proteolysis- and heat-resistant, chromosomally mediated superantigen expressed at neutral pH and elevated oxygen concentrations, produced by $90\%$ of menstruation-associated TSS strains.

Bound coagulase

Form of coagulase attached to Staphylococcus aureus that directly converts fibrinogen to insoluble fibrin, causing the bacteria to clump.

Free coagulase

Secreted enzyme that reacts with coagulase-reacting factor to form staphylothrombin, which then catalyzes the conversion of fibrinogen to insoluble fibrin.

Hyaluronidase

Staphylococcus aureus enzyme that hydrolyzes hyaluronic acids in the acellular matrix of connective tissue.

Staphylokinase

Fibrinolysin enzyme produced by Staphylococcus aureus that dissolves fibrin clots.

Staphylococcal Scalded Skin Syndrome (SSSS)

Disease primarily affecting neonates (Ritter disease) characterized by perioral redness spreading body-wide, epidermal desquamation, and large cutaneous blisters containing clear fluid devoid of organisms or leukocytes.

Impetigo

Superficial pyogenic cutaneous infection affecting young children.

Folliculitis

Pyogenic cutaneous infection localized in the hair follicles.

Furuncles

Cutaneous pyogenic infections, also known as boils, representing an extension of folliculitis.

Carbuncles

Coalescence of multiple furuncles extending into deeper subcutaneous tissues.

Bullous Impetigo

Localized form of SSSS presenting as superficial skin blisters that contain the bacterial organism, without sloughing of the skin.

Mannitol-Salt Agar Fermentation

Diagnostic culture property that differentiates Staphylococcus aureus from other staphylococcal species, as S. aureus ferments mannitol and grows in high salt concentration.