Important resistant bacteria Flashcards
Why do antibiotic resistant bacteria arise?
- Poor antibiotic stewardship
- Over prescribing
- Poor access diagnostic facilities
- Lack of knowledge on dosing - Non-compliance
- Overuse in agriculture
- Mutations
How did resistance arise in Penicillin-resistant S.pneumoniae?
Modification of the penicillin binding protein (transpeptidase).
Main infections associated with Penicillin-resistant S.pneumoniae?
Community acquired pneumonia
Blood stream infections
Meningitis
What other antibiotics is Penicillin-resistant S.pneumoniae resistant to?
- Cephalosporins
- Clarithromycin
- Tetracyclines
- Co-trimoxazole
What do we use to prevent pneumococcal infection?
PPSV23
23 valent pneumococcal polysaccharide vaccine.
Main infections caused by MRSA?
Similar to MSSA
SSI’s
BSI’s
Device-related infections
Lab features of MRSA?
- Gram positive cocci in clusters
- Coagulase postive
- Catalase postive
- Mannitol fermenter
How does resistance arise in MRSA?
Modification of penicillin binding protein.
Associated with the mecA gene., on chromosome
What other antibiotics can MRSA be susceptible to?
Gentamycin
Eryhromycin
Ciprofloxacin
What alternative antibiotics can be used to treat MRSA infection?
Glycopeptides
Daptomycin
Linezolid (restricted use)
Tigecycline (not for BSI’s)
Side effects of linezolid?
Metabolic acidosis Potential interactions with SSRI's and tricyclic antidepressants Peripheral and optic neuropathy Increase in bp Myelosuppression
How do we prevent MRSA infection?
- Contact precautions and isolation
- Antibiotic stewardship
- Decolonisation of colonised individuals
Lab features of VRE?
Gram positive cocci in chains
Small magenta colonies on Columbia blood agar
What infections may VRE cause?
UTI's Peritonitis BSI's Central line infections SSI's
Where are VRE found?
Colonised in the enteric tract and vagina
Can be found in community and healthcare settings
How does resistance occur in VRE?
Modification of AA side chains in cell wall
What antbiotics is vanA+ VRE resistant to?
Vancomycin and Teicoplanin
What antibiotics is vanB+ VRE resistant to?
Vancomycin
Examples of ESBL Enterobacteriacea?
E. coli, K. pneumoniae, P. mirablis
Main infections caused by ESBL producers?
UTI
Intrabdominal infections
SSI
Mech of resistance of ESBL producers?
Produces ESBLs which hydrolyse many B-lactams
What antibiotics are ESBL producers resistant to.
B lactams
- Penicillin and third generation cephalosporins (cefotaxime and ceftazidime)
May also be resistant to aminoglycosides and fluoroquinolones
What may be suitable to treat ESBL infection?
Meropenem and Imipenem (carbapenems)
- Last resorts
- V broad spec
