Resistance

Question 1

Types of resistance

Answer 1

Inherent

Acquired - mutations/selction and exchange between strains

Question 2

Vertical evolution

Answer 2

Non-mutated survive and grow after others have died

Occurs in the absence of drugs

Question 3

Horizontal evolution

Answer 3

Acquired from other bacteria
Conjugation - cell-cell contact
Transduction - genes transported in bacterial virus
Transformation - DNA acquired from environment

Question 4

Resistance mechanisms 1

Answer 4

Conversion of active drug to inert product by enzyme

Beta-lactamases

Question 5

Resistance mechanisms 2

Answer 5

Reduction in cellular permeability to antibiotic

Drug doesn’t reach toxic levels - Efflux pump, membrane/wall change

Question 6

Resistance mechanisms 3

Answer 6

Changes in antibiotic target site

Drug can no longer bind and have effect

Question 7

Resistance mechanisms 4

Answer 7

Altered metabolic pathway

Question 8

Superbug - Clostridium difficile

Answer 8

Anitibiotics kill normal flora, C.diff takes over and releases toxins

Question 9

Superbug - Glycopeptide Resistant Enterococci

Answer 9

G+ve cocci (E. faecalis)
Intrinsic - PBPs bind less well 
Acquired - beta-lactamases
Manadatory reporting 2003-2013
Vacnomycin and teicoplanin resistance
Not highly virulent, limited treatment gives danger

Question 10

Superbug - Carbapenem Resistant enterobacteriaceae

Answer 10

G-ve bacilli (gut flora -E.coli)
Growing resistant to many antibiotics
Current treatment - polymixins, aminoglycosides

Question 11

Superbug - Tuberculosis

Answer 11

Mycobaterium tuberculosis
Rifampicin, Isoniazid, Pyrazinamide, Ethambutol
BCG vaccination
MDR-TB - regular treatment ineffective (RI)

Question 12

Methicillin-resistant Staphylococcus aureus

Answer 12

G+ve cocci
Variant to penicillin binding protein. Beta-lactams can’t bind.
HA-MRSA - patient to patient in hospitals

Question 13

5 year antimicrocial plan

Answer 13

1. Surveillance and Guidance
2. Antimicrobial stewardship
3. Increasing awareness
4. Improving training and education
5. Research to understand, diagnose and treat
6. Drug and therapeutic development
7. International collaborations