MMSC 428 Final (100% Accurate Answers)

Staphylococcus aureus correct answers -gram positive cocci in clusters -facultative aerobe (prefers O2) -halotonic -ferment mannitol (yellow on MSA plate) -catalase + -*coagulase +* -clumping factor + -medium sized b-hemolytic white colonies -serological tests for TSST-1 and DNA probes are the best diagnosis methods -most clinically significant staphylococcus -important cause of nosocomial infection staphylococcus aureus virulence mechanisms correct answers -protein A: virulent cell wall protein that binds to IgG antibodies and prevents them from being active -hemolysins: produce B-hemolysis of RBCs -exfoliatin: causes epidermal layer of skin to peel off -pyrogenic toxin: causes fever -toxic shock syndrome toxin 1 (TSST-1): super antigen over stimulates the T cells and produces cytokine storm -panton valentine leukocidin (PVL): lyses WBCs, platelets and RBCs -staphycoagulase: activates fibrin to cause clotting and prevent WBCs from reaching the bacteria -hyaluronidase: breaks down hyaluronic acid in tissue to spread bacteria -lipases & proteases: destroy host tissues and spread bacteria staphylococcus aureus clinical manifestations correct answers -furuncle: large raised suppurative dome shaped boil due to infection of oil gland or hail follicle -carbuncle: a furuncle that progresses and infects a deeper level of the skin, infection causes systemic symptoms of fever and chills -impetigo: bullous (5 mm) domed fluid filled pustules surrounded by zone of erythema, mainly seen in children -cellulitis: inflammatory infection of connective tissue -staphylococcal scalded skin syndrome (SSS): release of exfoliatin exotoxin causes exfoliative dermatitis with red peeling skin that resembles a burn, mainly in children and newborns -toxic shock syndrome (TSS): release of TSST-1 and enterotoxin B cause systemic symptoms including fever, liver and kidney damage, vomiting, diarrhea, muscle aches and rash, menstrual and non-menstrual forms -endocarditis -intoxication food poisoning: food is contaminated with enterotoxins (no actual bacteria) and causes vomiting and diarrhea -nosocomial infections: wound infections, osteomyelitis, biofilm on body implants -childhood infections: SIDS, head and neck infection staphylococcus aureus drug resistance correct answers -penicillin resistant due to acquiring beta-lactamase genes