51.   In combination, they keep the germ from developing drug resistance.

52.   In nature, drug resistance in bacteria usually takes several years to develop.

53.   Old ones, such as tuberculosis, are returning because of drug resistance, homelessness and overcrowding.

54.   Researchers are not sure how big a role drug resistance plays.

55.   Public health officials are concerned that overuse of antibiotics in livestock is leading to drug resistance in humans, making it harder for doctors to treat bacterial infections.

56.   She cautioned that drug resistance may play a bigger role in patients who have had longer treatment with antiviral drugs.

57.   Testing every newly infected patient for drug resistance would be impractical because the tests cost several thousand dollars and are difficult to interpret, Pomerantz said.

58.   The AIDS virus develops drug resistance by mutating.

59.   The American Society for Microbiology has called drug resistance a public health emergency.

60.   The primary reason for the increase, they said, is the development of drug resistance in the virus during treatment.