Duringtheirlaboratorytesting,ifdisinfectantsarecarriedoverinto
microbial cultures, could the results be affected? Explain.
Definedisinfection.Howdoesitdifferfromantisepsis?
Whatdoesbactericidalmean?Bacteriostatic?Virucidal?Fungistatic?
Whyarecontrolculturesnecessaryinevaluatingdisinfectants?
Whatfactorscaninfluencetheactivityofadisinfectant?
Whydomicroorganismsdifferintheirresponsetodisinfectants?
Whatmicroorganismsaremostsusceptibletodisinfectants?
Which microbial forms are most resistant to disinfectants?
Howcanbacteriostaticandbactericidaldisinfectantsbedistinguished?
10.What is an iodophor? What is its value? 11.Why are bacterial endospores a problem in the hospital environment? 12.Briefly discuss disinfection and antisepsis in relation to patient care. 13.In addition to using a hand scrub, what other precaution in necessary for
health-care personnel to prevent spreading infection by their hands when
in the operating room? 14.Would you expect that long or artificial fingernails interfere with the
effectiveness of hand scrubs? Why? 15.Why is it not suitable to wear rings with stones in hospital settings? 16.Why should hands be washed before and after dressing changes even
though gloves must be worn during the procedure?
Exercise 15.1
Questions 1. Defineanantimicrobialagent. 2. Whatismeantbyantimicrobialresistance?Susceptibility? 3. Whyarepureculturesusedforantimicrobialsusceptibilitytesting?
Woulditbeacceptabletouseamixedcultureforthistest?Why?
List three factors that can influence the accuracy of the test.
Whenperformingabrothdilutiontest,whyisitnecessarytoincludea
growth control tube? A sterility control tube?
Howcantheminimumbactericidalconcentrationofanantimicrobialagent
be determined from an MIC assay?
Couldanorganismthatissusceptibletoanantimicrobialagentin
laboratory testing fail to respond to it when that drug is used to treat the
patient? Explain.
Areantibacterialagentsusefulinviralinfections?Explain.
10.Why is it better to use the wordsusceptiblerather than the wordsensitive
in describing an organism’s response to a drug? When speaking of the
patient, what does the termdrug sensitivitymean? 11.Describe a mechanism of bacterial resistance to antimicrobial agents. 12.If the laboratory isolatesS. aureusfrom five patients on the same day, is it
necessary to test the antimicrobial susceptibility of each isolate? Why?