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26 Cards in this Set
- Front
- Back
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What are the two main groups of microflora on the hands?
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Resident microflora (this consists mainly of staphylococci on the surface of the hands and within the pores of the skin and Proprionobacterium acnes – an anaerobic microorganism)
Transient microflora – this consists of many other bacteria that the person has picked up on their hands (only stay on for a short time, and can easily pass on to others) |
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Unmedicated soap will principally remove the transient microflora.
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Washing hands in medicated soap or antiseptic (eg chlorhexidine) will reduce the total nimber of organisms on the skin – both resident and transient.
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Alcohol gel may be used as an alternative to washing in medicated
soap EXCEPT in trying to control Clostridium difficile when soap and water must be used. |
Antiseptics have a sustained action upon the microflora whereas unmedicated soap does not.
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Streptococcus pyogenes is sensitive to which antibiotic?
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Penicillin
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There are many different types of penicillins. Penicillins and a chemically related molecule called cephalosporins belong to the group of antibiotics called -lactams.
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β-lactams
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What can β-lactams be divided into?
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Penicillins and cephalosporins (constitute a subgroup of antibiotics called cephems)
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What are β-lactamases?
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Molecules which destroy β-lactams
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What are the major groups of antibiotics?
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β-lactams
Aminoglycosides Tetracyclines Macrolides Glycopeptides Nitroimidazoles |
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What is a erythromycin?
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A Macrolides (antibiotic)
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What is special about teicoplanin?
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In the group of glycopeptides. It is active only against Gram + bacteria
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What is special about metronidazole?
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In the group of nitroimidazoles. It is active only against anaerobic bacteria
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What are the three ways of measuring antibiotic sensitivity?
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A disc containing the antibiotic placed on an agar plate
E-test Different concentrations of antibiotic are incorporated into agar plates and the organism inoculated and the plates incubated (lowest conc to kill bacteria = minimum bactericidal concentration (MBC) |
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What is the 'E-test'?
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Where a calibrated strip of material containing varying concentrations of the antibiotic is placed on the plate in a similar fashion to the disc. After incubation there is variable inhibition of the growth and the point where the growth touches the strip identifies the minimum inhibitory concentration (MIC) of the antibiotic
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What is the minimum bactericidal concentration (MBC)?
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When different concentrations of antibiotic are placed on agar plats, the MBC is the lowest concentration of antibiotic that kills the bacteria.
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What are the main ways of making a laboratory diagnosis of an infection? (4)
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Microscopy, culture, serology (study of blood serum), PCR
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PCR does not give an indication of current infection or that the organism is alive but is very useful for detecting ______ _______ _________ eg ____________ or detcting antibiotic resistant bacteria eg ____)
Guess! 1514081110 |
Slowly growing organisms
Mycobacteria MRSA |
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How does serology help identify an infection?
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Antibodies can be found in serum
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What two items are used in serology to detect antibodies?
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Enzyme Linked Immunosorbent Assay (ELISA) or
Latex agglutination test (LA) |
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In serology, the presence of what indicates a recent infection? An old infection? What do antibodies show?
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IgM (immunoglobin M)
of IgG (immunoglobin M) indicates exposure to an infectious agent at some time in the past Antibody detection does not necessarily give an indication of current infection |
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In serology, detection of antibodies using ELISA or LA indicates what?
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Current infection
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Viruses can be grown on agar and gram stained T/F
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F!
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Gram-negative bacteria look what colour when they are stained?
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Blue/violet/black
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Gram-positive bacteria look what colour when they are stained?
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Red/pink
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What is the 'Ziehl-Neelsen stain'?
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A stain used to identify the presence of mycobacteria which stain red, from all other bacteria which stain green
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What colour to mycobacteria go with the ZN stain?
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Red. All other bacteria remain green.
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What stain is used for fungi? What colour do the fungi go?
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Grocott stain (fungi go brown)
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