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The New Antibacterial Fad: A New Threat

(Olympiades 2007: Toutes séries)

Antibiotics are not the only antimicrobial substances being overexploited today. Use of antibacterial agents - compounds that kill or inhibit bacteria but are too toxic to be taken internally -- has been skyrocketing as well. These compounds, also known as disinfectants and antiseptics, are applied to inanimate objects or to the skin.

Historically, most antibacterials were used in hospitals, where they were incorporated into soaps and surgical clothes to limit the spread of infections. More recently, however, those substances (including triclocarbon, triclosan and such quaternary ammodium compounds as benzalkonium chloride) have been mixed into soaps, lotions and dishwashing detergents meant for general consumers. They have also been impregnated into such items as toys, high chairs, mattress pads and cutting boards.

There is no evidence that the addition of antibacterials to such household products wards off infection. What is clear, however, is that the proliferation of products containing them raises public health concerns.
Like antibiotics, antibacterials can alter the mix of bacteria: they simultaneously kill susceptible bacteria and promote the growth of resistant strains. These resistant microbes may include bacteria that were present from the start. But they can also include ones that were unable to gain a foothold previously and are now able to thrive thanks to the destruction of competing microbes. I worry particularly about that second group - interlopers - because once they have a chance to proliferate, some may become new agents of disease.

The potential overuse of antibacterials in the home is troubling on other grounds as well. Bacterial genes that confer resistance to antibacterials are sometimes carried on plasmids (circle of DNA) that also bear antibiotic-resistance gene. Hence, by promoting the growth of bacteria bearing such plasmids, antibacterials may actually foster double resistance - to antibacterials.

Routine housecleaning is surely necessary. But standard soaps and detergents (without added antibacterials) decrease the numbers of potentially troublesome bacteria perfectly well. Similarly, quickly evaporating chemicals -¬such as the old standbys of chlorine bleach, alcohol, ammonia and hydrogen peroxide - can be applied beneficially. They remove potentially disease-causing bacteria from, say, thermometers or utensils used to prepare raw meat for cooking, but they do not leave long-lasting residues that will continue to kill benign bacteria and increase the growth of resistant strains long after target pathogens have been removed.

If we go overboard and try to establish a sterile environment, we will find ourselves cohabiting with bacteria that are highly resistant to antibacterials and, possibly, to antibiotics. Then, when we really need to disinfect our homes and hands - when a family member comes home from a hospital and is still vulnerable to infection - we will encounter many resistant bacteria. It is not inconceivable that with our excessive use of antibacterials and antibiotics, we will make our homes, like our hospitals, havens of ineradicable disease-producing bacteria.

By Stuart B. LEVY, Scientific American, March 1998 P. 48



Vocabulary
Fad: a short-lived interest.

Questions
(Answer in your own words.)

1) On the basis of the text, explain what antibacterials are. (2 points)
2) What are the two paradoxical effects that may result from the overuse of antibacterials and antibiotics? Explain how these effects are paradoxical. (3 points)
3) According to the text, how is resistance to antibacterials and antibiotics caused? (3 points)
4) What solution (s) does the writer suggest to reduce resistance to antibacterials and antibiotics? (3 points)
5) Taking into account the information contained in the text, write a 150¬word advertisement to sensitive and guide customers about the use of antibacterial and antimicrobial substances they purchase. (9 points)