Staphylococcus (IP4: Exam 1) USE AT YOUR OWN RISK

Learning Objective #1:

Identify morphological traits for Staphylococcus spp.

Grape-like clusters, gram-positive, spherical

Learning Objective #2:

Describe the role of blaZ in penicillin resistance for MSSA.

resistance mwahaha

BlaZ? What is?

MSSA beta-lactamase (not is responsible for methicillin resistance, because low level blaZ is found in all staph aureus now)

Affects penicillin G, VK, ampicillin, etc.

However, it does not affect antistaphylococcal penicillins (nafcillin, methicillin, etc.)

MRSA? What is?

MRSA resist methicillin (antistaphylococcal penicillins)

Use Vancomycin for treatment of MRSA

reason for MRSA is due to mecA (from SCCmec) encoded low affinity penicillin binding protein where the target for penicillin not like penicillin therefore not treat as well

PBP? Imporatn why?

They are main cause for S. Aureus resistance

NOT beta-lactamases

PBP2a not bind to most what...?

Penicillins and cephaloporins

Use Vancomycin

SCCmec encodes what...?

mecA gene - MRSA

erm - macrolides

crr gene - recombinases

tet gene - tetracycline

aac - aminoglycosides

VanHAX explain?

Alter d-ala to d-lactate so piranha plant can't bind to d-ala residue and crosslinking is prevented

D-zone test what is?

Clindamycin resistance

Alpha-hemolysis

Green

Beta-hemolysis

Clearing

gamma-hemolysis

white blood cells

PVL?

interacts with gamma-hemolysins to form 6 different toxins (present in almost all community-acquired MRSA)

associated with SCCmec IV

toxic shock syndrome toxin

enterotoxin type F

exfoliative toxins cause?

scalded skin syndrome

skin erythema and separation

removes protective coating to enhance infection

SIRS?

febrile (fever)

high white blood cells count

tachypnea

endocarditis...?

IV drug users

hemodialysis patients

S. epidermis?

catheter

bioflims of protehsis

75% of all non-coagulase positieve infection

are you slep deprive?

yes :(

s. lugienssis

emerging but rare right now