Word: bacterias
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Dates: during 1990-1999
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Antibiotic-proof bacteria are spreading around the globe because of the enormous increase in tourism and business travel in recent decades. Last month a woman came to a New York City emergency room with a strain of cholera picked up in Ecuador that was impervious to a variety of antibiotics. Penicillin- resistant strains of gonorrhea, originally noted in Africa around 1976, have cropped up in the Philippines, Thailand and the Washington Heights section of New York City. Public health officials are particularly concerned about potentially fatal forms of dysentery in Central and South America that are resistant to half...
Quite possibly the earth's most ancient life-forms, bacteria are experts at the game of survival. Throw a bunch of them onto an ice floe or into the steaming heart of Old Faithful, and one or another of the unicellular beasties will probably turn out to possess a critical trait that enables it to live through the ordeal and pass that trait on to trillions of descendants, a rapid example of evolution through natural selection. Just as predation by lions has gradually increased the swiftness of gazelles, the use of antibiotics has spurred the emergence of bacteria that...
...onto a specific molecule on its cell wall, a change in that molecule could make it impossible for the antibiotic to stick to its target. It's something like the protect-the-perimete r strategy used by defenders of ramparts on medieval fortresses. In other cases, says Neu, the bacteria develop enzymes capable of destroying the antibiotics and even molecular pumps that expel the drugs from the cell. The most recent example of bacterial resourcefulness came to light only two weeks ago. By deleting a single gene, an English-French research team announced, certain strains of the TB germ have...
Once a bacterium has a protective combination of genes, they are duplicated every time the bacterium reproduces itself. Moreover, the microbe can pass its genetic shield to a different strain of bacteria through a process called conjugation, the bacterial equivalent of sex. In addition to exchanging DNA in the form of chromosomes, conjugating bacteria can swap smaller snippets of DNA called plasmids. Like viruses, plasmids make exceedingly effective shuttles for carrying drug-resistant traits from one bacterium to another...
...infections in some extremely ill patients with massive doses of antibiotics, and when one drug didn't work, they tried another and another. From the standpoint of their individual patients, the physicians could do no better. The consequences for society as a whole, however, are troubling. Stubborn strains of bacteria resistant to many different antibiotics have taken up permanent residence in hospitals around the world. Experts predict that the effectiveness of widely active antibiotic agents such as the cephalosporins, which entered clinical use in 1964, will soon be dramatically reduced...