MIC 541-Exam 4- Antimicrobials V-3

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What are low affinity PBPs?

Mutated PBPs that have a lower affinity for certain B-lactam antibiotics than in their native form
Mutated PBPs that have a lower affinity for B-lactam Antibiotics than in their native form are called what?

Low affinity PBPs
What low affinity PBPs were presented in class?
- PBP 5
- PBO 2a and 2
- Others: those in PRSP and PISP
PBP 5 is found in what bacteria?

Enterococci
Enterococci carry what type of Low affinity PBPs?

PBP 5
What bacteria are PBP 2a and 2' in?
- Staphylococci
- MRSA
Prior to 1990, what bacteria was not tested for susceptibility?

S. pneumoniae
What are the only drugs that S. pneumoniae not resistnat to today?

Glycopeptides and flouroquinolones
What very resistant bacteria is susceptible to glycopeptide and flouroquinolones?

S. pneumoniae
Since 1990 what resistant bacteria has emerged?

S. pneumoniae
How does S. pneumoniae develop resistance?
- mutate PBPs
- foreign DNA from other Sterptococci
How is S. mitis important to S. pneumoniae resistance?

S. mitis dies in the mouth and S. pneumoniae scavenges the DNA for resistance
What has been the main avenue for S. pneumoniae to gain resistance to Penicillins?

Scavenged DNA (particularly from S. mitis)
When was the first time that we realized we had penicillinases in S. aureus?

1945
When did the first MRSA emerge?

1961
MRSA is resistant to what?

All B-lactams except ceftaroline
MRSA is resistant to all B-lactams except which one?

Ceftaroline
50% of isolates in hospitals are what type of S. aureus?

MRSA
How common is MRSA in hospitals?

50% of isolates
What areas are MRSA spreading in?
- Community
- Nosocomial
- Veterinary
What are examples of glycopeptides?
- Vancomycin
- Teicoplanin
- Telavancin
Vancomycin, Teicoplanin and Telavancin are of what antibacterial group?

Glycopeptides
What is teh Molecular weight of Glycopeptides?

Over 1000
Are Glycopeptides active against Gram negatives?

No, they are too big to cross the porins in the outer membrane
Why are glycopeptides not active against Gram negative bacteria?

They are too large to cross through porins of the outer membrane
Why is Vancomycin the drug of last resort?

It is Toxic
What type of bacteria can Vancomycin protect against?

Gram positive
Why is Vancomycin used?

For very resistant bacteria
How long did take for Enterococcus to develop resistance to Vancomycin ?

30 years
How many genes did the Enterococcus have to develop to become resistant to Vancomycin?

8 genes
The resistance for what is encoded on 8 genes?

Vancomycin
What are the 8 genes that infer resistance for Vancomycin called?

Van genes
What is the mechanism of Van genes resistance?

Altered target
What is a VRE?

Vancomycin resistant enterococci
VRE has van genes that alter what?

The target
Resistance to vancomycin in MRSA took how long to develop?

40 years
What type of resistance to vancomycin developed in MRSA?

Intermediate
What bacteria developed an intermediate resistance to Vancomycin?

MRSA
What is the mechanism of Vancomycin intermediate-resistance in MRSA?

thicker cell wall that binds the drug and blocks it from the PBPs
What is VISA/GISA?
- Vancomycin intermediate staphylococcus aureus
- AND the newer name
- Glycopeptide intermediate staph aureus
What bacteria developed thicker walls to block vancomycin?

MRSA
What bacteria is referred to as VISA/GISA?

MRSA with intermediate Vancomycin resistance
What is the name for Vancomycin intermediate-resistant MRSA?

VISA or GISA

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kyleannkelsey

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MIC 541-Exam 4- Antimicrobials V-3

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MIC 541-Exam 4- Antimicrobials V-3

Updated

2013-04-15T01:05:53Z