AMR Flashcards
What are antimicrobials used for?
To treat infections caused by bacteria (antibiotics), fungi and yeast (antifungals), parasite (antiparasitics) and viruses (antivirals)
What is AMR?
Antimicrobial resistence - occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials.
What are consequences of AMR?
There is limited treatment for infections, increased risk of transmission, accumulation of antimicrobial resistence-determinants
What does panresistence mean
Resistence to all drugs
What are the main drivers of AMR?
Overuse and misuse of antimicrobials, poor hygiene/sanitation, failure of infection control measures in healthcare or agriculture.
What are the types of horizontal gene transfer?
Transformation, Transduction, Conjugation
What are plasmids?
Small extra chromosomal DNA molecules that can replicate independently
What are MDROs
Multidrug resistant organisms - organisms resistant to 3 or more classes of antimicrobial drugs
Examples of Beta-lactam antibiotics
Penicillins, cephalosporins, carbapenems, monobactams
Examples of Gram Positive Organisms
Staphyloccus species, Enterococcus spp
What is Staphlococcus aureus?
A Gram positive cocci that is arranged in clusters. It is significant pathogen and commensal of microbiota of the skin and upper respiratory tract. It is the infection most often associated with the skin, UTI, BSI, osteomyelitis, food poisoning
What antibiotic fights a staphylococcus aureus infection?
Cephalexin for uncomplicated skin infection.
Vancomycin for treatment of complicated infections including bacteraemia, deep-seated infections, pneumonia
What does MRSA stand for
Methicillin-resistant Staphylococcus aureus
What is Enterococci?
A Gram positive cocci that appears in chains or as diplococci. It is a lactic acid bacteria - produces lactic acid as a biproduct of fermentation. Causes UTIs, bacteraemia, endocarditis, meningitis
What antibiotics fights Enterococcus spp?
Nitrofurantoin (nitrofuran class) for uncomplicated UTI.
Vancomycin (glycopeptide class) for invasive infections.
How does vancomycin work?
Vancomycin binds to the D-Ala-D-Ala terminus of the peptidoglycan precursor, inhibiting transglycosylation and transpeptidation, consequently causing cell wall damage.
How does Vancomycin-Resisant Enterococci (VRE) work?
They acquire the vanA or vanB gene that alters the D-Ala-D-Ala target of vancomycin.
What are the treatment options for vancomycin-resistant strains?
Linezoid and daptomycin, final resort antibiotics, economic associations
What is VRSA and what is it mediated by
Vancomycin-resistant Staphylococcus aureus mediated by a vanA gene cluster which is transferred from VRE via transposon.
What are control measures of AMR bacteria?
Screening on admission, pre-procedure or on entering intensive wards, surveillance reporting, patient isolation, hygiene measures
Where are MRSA swabs taken from and what are they plated on?
Nose, axilla, groin are plated on selective and differential commercial media in hospital labs.
Where are VRE swabs taken from and what are they plated on?
Rectal are plated on selective and differential commercial media in hospital labs
What is a bacteriophage?
A virus that targets bacteria
Process of bacteriophage infecting host
A bacteriophage attaches itself to a susceptible bacterium and infects the host cell. Following infection, the bacteriophage hijacks the bacterium´s cellular machinery to produce viral components. New bacteriophages assemble and burst out of the bacterium in a process called lysis.
What are Carbapenems?
Drugs of last resort, with broad spectrum activity against Gram neg and some Gram pos.
What are CPEs?
Carbapenemase-producing Enterobacterales - are resistant to all antiboitics derived from penicillins and roughly half of all antibiotics are derived from penicillins.
