LAB S18 Flashcards
determine the susceptibility of microorganisms to one or several antimicrobial agents
Antimicrobial Susceptability Test
act against microorganisms by blocking essential cellular processes
antimicrobial agents
Antimicrobial agents block essential cellular processes which are: (4)
> cell wall synthesis
protein synthesis
DNA replication/ transcription
cellular respiration
the property of being able to inhibit microbial growth
microbiostatic
the property of being able to kill microbes
microbicidal
pharmaceutical agents that include antibiotics (antibacterials), antifungal, antiviral , and antiparasitic drugs
antimicrobial drugs
susceptibility profile of a microorganism
antibiogram
lowest concentration of an antibiotic that inhibits visible growth of a microorganism in an in vitro system
Minimum Inhibitory Concentration (MIC)
Three major uses of AST
- As a chemotherapeutic guide
- As an epidemiological surveillance tool
- As a laboratory diagnostic tool
AST is used when susceptibility of bacteria cannot be predicted from its identity. However, it is not needed if the susceptibility profile is predicatable.
Streptococcus pyogenes is predictably susceptible to:
penicillin
Anaerobes are predictably susceptible to:
metronidazole
Klebsiella pneumoniae is predictably resistant to:
ampicillin
Proteus species is predictably resistant to:
nitrofurantonin and tetracyclines
Susceptibility:
Streptococcus pyogenes
penicillin
Suscpetibility:
Anaerobes
metronidazole
Resistance:
Klebsiella pneumonae
ampicillin
Resistance:
Proteus species
nitrofurantoin and tetracyclines
property of antimicrobial drugs wherein it acts within the host without damaging the host
selective toxicity
Three purposes of AST as an epidemiological surveillance tool
Aid in
- monitoring susceptibility patterns in a region or hospital
- appropriate empiric antibiotic therapy (giving amoxicillin for community acquired pneumonia)
- monitoring emergence of acquired resistance
Five most common bacterial pathogens for communith-acquired pneumonia (CAP)
- Streptococcus pneumoniae
- Haemophilus influenzae
- Chlamydophila pneumoniae
- Mycoplasma pneumoniae
- Moraxella catarrahlis
Most community acquired pneumonia bacterial pathogens are susceptible to:
amoxicillin
Streptococcus bacteria can be identified in laboratpry diagnosis through its susceptibility to:
Bacitracin
Bacitracin inhibits what groups of Streptococcus bacteria:
99% group A (S. pyogenes)
small percentage of group B
10-20% of group C and G
used routinely for testing common, rapidly growing, and certain fastidious bacterial pathogens
Kirby-Bauer Agar Disk Diffusion method