Biol 2460 Chap 14.5 - Drug Resistance

How does Antibiotic resistance arise?

from increased selective pressure

What are MDR’s

Multidrug-resistant microbes

• Cross-resistance – one mechanism confers resistance to multiple drugs

• causes nosocomial(hospital) infections

What are the ESKAPE microbes?

• Enterococcus faecium

• Staphylcoccus aureus

• Klebsiella pneumoniae

• Acinetobacter baumanii

• Pseudomonas aeruginosa

• Enterobacter spp

What is VRE?

Vancomycin-resistant enterococci (VRE)

• Target modification of peptide component in cell wall; prevent binding
  

What is VRSA?

Vancomycin-resistant S. aureus (VRSA)

• Horizontal gene transfer from patients infected with VRE and MRSA

What is VISA?

Vancomycin-intermediate S. aureus (VISA)

• Increase in targets; binding to outer cell wall

What is MRSA?

Methicillin-resistant S. aureus (MRSA)

• Acquisition of new low-affinity PBP; resistance to all β-lactams

What is ESBLs?

Extended-spectrum β-lactamases (ESBLs)

• Resistance to penicillins, cephalosporins, monobactams, β-lactamase-inhibitors, but NOT carbapenems

• ESBLS found on plasmids that have other drug resistances

What is CRE?

Carbapenem-resistant Enterobacteriaceae (CRE)

• Produce carbapenemases (β-lactamases that inactivate all β-lactams)

• Efflux pumps and uptake prevention

• Some have developed pan-resistance (resistance to all antibacterials)

What are MDR-TB?

Multidrug-Resistant Mycobacterium tuberculosis (MDR-TB)

• Resistant to both rifampin and isoniazid

What are XDR-TB?

Extensively drug-resistant Mycobacterium tuberculosis (XDR-TB)

• Additionally resistant to any fluoroquinolone and at least 1 of 3 others

What is the first E in ESKAPE microbes?

• Enterococcus faecium

What is the S in ESKAPE microbes?

• Staphylcoccus aureus

What is the K in ESKAPE microbes?

• Klebsiella pneumoniae

What is the A in ESKAPE microbes?

• Acinetobacter baumanii

What is the P in ESKAPE microbes?

• Pseudomonas aeruginosa

What is the last E in ESKAPE microbes?

• Enterobacter spp