A student is shopping for antibacterial hand cleansers and is trying to decide which one to buy. One is a "waterless" hand gel containing 70% isopropanol, the second is an "antibacterial" hand soap containing triclosan (a phenolic), and the third is a wipe that lists benzethonium chloride (a synthetic quaternary ammonium salt) as the active ingredient. Compare and contrast these cleansers in

terms of the action of the antimicrobial ingredient and the level of disinfection (degerming, germistatic, germicidal).

What will be an ideal response?


All three are germicidal, although not all to the same degree. The alcohol of the waterless hand cleaner is a germicide that disrupts cytoplasmic membranes and denatures proteins. It is not effective against bacterial endospores or fungal spores, and it has limited effect on nonenveloped viruses. The alcohol evaporates quickly, so the germicidal effect is short term. The waterless hand cleaner is an intermediate-level disinfectant and is not an effective degermer. The hand soap contains a phenolic, which also damages cytoplasmic membranes and denatures proteins, and is effective on the same range of microbes as the alcohol. Phenolics are intermediate-level disinfectants that persist on surfaces for long periods of time, providing extended disinfection. If used with running water and the hands are vigorously rubbed, the hand soap can be an effective degermer. Synthetic "quats" (quaternary ammonium compounds) disrupt cell membranes. They are effective against fungi, enveloped viruses, and most bacteria, but not against nonenveloped viruses, nor on endospores. Quats are low-level disinfectants that are germicidal for some microbes. The action of using and discarding the wipe provides some degerming effect.

Biology & Microbiology

You might also like to view...

Dumping refers to the practice of

a. flooding a foreign market with large quantities of a good. b. selling a product abroad at a price below cost or below the domestic price. c. exporting inexpensive products to foreign countries. d. selling surplus goods abroad with counterfeit brand names.

Biology & Microbiology

In DNA, pyrimidines are covalently bonded to the pentose sugar. Which one of the following statements is correct?

a. the 1'C of the sugar is covalently bonded to N1 in the pyrimidine ring b. the 1'C of the sugar is covalently bonded to N9 in the pyrimidine ring c. the 1'C of the sugar is hydrogen bonded to N9 in the pyrimidine ring d. the 1'C of the sugar is hydrogen bonded to N1 in the pyrimidine ring

Biology & Microbiology

Which one of the following terms applies to the phylum Bryozoa?

A. Radial cleavage B. Parazoa C. Radial symmetry D. Lophophore E. Deuterostome

Biology & Microbiology

The diameter of a blood vessel will be reduced by the contraction of ________

a. cardiac muscle b. smooth and cardiac muscles c. skeletal and cardiac muscles d. smooth muscle e. skeletal muscle

Biology & Microbiology