Question

What is meant by the term, “coliform”? That is, what Gram-staining, morphology, aerobicity, and lactose metabolic properties must a bacterium have to be considered a coliform. Note: partial credit will not be awarded for this question.

What bacterium (Genus and specific epithet) is commonly used as a fecal indicator?

What is meant by the term “sanitize”?

Why might an antimicrobial agent such as tea tree oil not exhibit antimicrobial activity in our Kirby-Bauer disc diffusion assay?

What is the mechanism of action of phenolics such as Lysol®?

Why should one make new bleach disinfectant solution on a regular basis? That is, why isn't bleach disinfectant shelf-stable for much more than one day?

For what does the acronym, MIC, stand? That is, what is the word for each letter?

What is the minimum pH required for Methyl Red to change color so as to register positive for the MR test?

Answer 1

Answer 1)Coliforms are present in feces,these are rod shaped,Gram negative and spore forming incubated at 35 to 37 degree centigrate. Gram staining-Coliforms are Gram negative bacteria, example:-Enterobacter. Morphology-These are rod shaped,aerobicity-usually aerobic and mesophilic, Lactose metabolic property-Coliforms can ferment lactose with production of as and acid

2) E. coli is a particular bacterium used as an fecal indicator, the subgroups are Enterococci and streptococci

3) The term sanitize means to make a substance hygenic or germ free

4) Antimicrobial agent such as tea tree oil not exhibit antimicrobial activity in disc diffusion assay as tea tree oil exhibits strong antibacterial activity in zone and inhibits the growth of other microbes

5)Mechanism of action of Lysol works as the disinfectant as these are highly oxidizing products, and acts on cell membrane by inactivation of cytoplasm. Lysol works on hard and soft surfaces and consist of chemical benzalkonium chloride,hydrogen peroxide that has the property of disinfectant

6)New bleach disinfectant should be made on regular basis and the shelf is not stable for more than one day as the diluted liquid is susceptible to degradation of components from different sources and the parameters such as temperature, light and contamination would break the components of disinfectants into simple components

7)MIC stands for Minimum Inhibitory concentration,the smallest concentration of antibitic that inhibits growth of bacterium

8) Minimum pH required for methyl red to change colour is 4.4, the test organism produces acid from carohydrate and when the culture medium turns red after the addition of methyl red by fermentation of glucose.