Resistance Flashcards
Types of resistance
Inherent
Acquired - mutations/selction and exchange between strains
Vertical evolution
Non-mutated survive and grow after others have died
Occurs in the absence of drugs
Horizontal evolution
Acquired from other bacteria
Conjugation - cell-cell contact
Transduction - genes transported in bacterial virus
Transformation - DNA acquired from environment
Resistance mechanisms 1
Conversion of active drug to inert product by enzyme
Beta-lactamases
Resistance mechanisms 2
Reduction in cellular permeability to antibiotic
Drug doesn’t reach toxic levels - Efflux pump, membrane/wall change
Resistance mechanisms 3
Changes in antibiotic target site
Drug can no longer bind and have effect
Resistance mechanisms 4
Altered metabolic pathway
Superbug - Clostridium difficile
Anitibiotics kill normal flora, C.diff takes over and releases toxins
Superbug - Glycopeptide Resistant Enterococci
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
Superbug - Carbapenem Resistant enterobacteriaceae
G-ve bacilli (gut flora -E.coli)
Growing resistant to many antibiotics
Current treatment - polymixins, aminoglycosides
Superbug - Tuberculosis
Mycobaterium tuberculosis
Rifampicin, Isoniazid, Pyrazinamide, Ethambutol
BCG vaccination
MDR-TB - regular treatment ineffective (RI)
Methicillin-resistant Staphylococcus aureus
G+ve cocci
Variant to penicillin binding protein. Beta-lactams can’t bind.
HA-MRSA - patient to patient in hospitals
5 year antimicrocial plan
- Surveillance and Guidance
- Antimicrobial stewardship
- Increasing awareness
- Improving training and education
- Research to understand, diagnose and treat
- Drug and therapeutic development
- International collaborations
