Health and medical news from the National Institutes of Health, the preeminent medical institution in the world... Antibiotic Resistance    The triumph of antibiotics over disease-causing bacteria is one of modern medicine's greatest success stories. Since these drugs first became widely used in the World War II era, they have saved countless lives and helped to avoid serious complications of many feared diseases and infections.     After more than fifty years of widespread use, however, many antibiotics are not as effective as they once were.     Over time, some bacteria have developed ways to resist the effects of antibiotics. Widespread use of antibiotics is thought to have spurred evolutionary changes in bacteria that allow them to survive these powerful medications. While antibiotic resistance benefits the microbes, it presents humans with two big problems: it makes it more difficult to remove infections from the body and it increases the risks of acquiring infections in a hospital.     Diseases such as tuberculosis, gonorrhea, malaria, and childhood ear infections are now more difficult to treat than they were decades ago. Drug resistance is an especially difficult problem for hospitals because they care for critically ill patients who are more vulnerable to infections than the general population and therefore require more antibiotics.     Heavy use of antibiotics in these patients hastens the mutations in bacteria that bring about drug resistance. Unfortunately, this worsens the problem by producing bacteria with greater ability to survive even our strongest antibiotics. These even stronger drug-resistant bacteria continue to prey on vulnerable hospital patients.     To help curb this problem, the Centers for Disease Control and Prevention [CDC] provides hospitals with prevention strategies and educational materials to reduce antimicrobial resistance in health care settings.     According to CDC statistics, nearly two million patients in the United States get an infection in the hospital each year Of those patients, about ninety thousand die each year as a result of their infections.     More than seventy percent of bacteria that cause hospital-acquired infections are resistant to at least one of the drugs most commonly used to treat them. Patients infected with drug-resistant organisms are more likely to have longer hospital stays, requiring treatments with second or third choice drugs that may be less effective, more toxic or more expensive.    Antimicrobial resistance is driving up health care costs, increasing the severity of disease, and increasing the death rates from certain infections.     A key factor in the development of antibiotic resistance is the ability of infectious organisms to adapt quickly to new environmental conditions. Bacteria are single-celled organisms that, compared with higher life forms, have small numbers of genes. Therefore, even a single random gene mutation can greatly affect their ability to cause disease. And because most microbes reproduce by dividing every few hours, bacteria can evolve rapidly. A mutation that helps a microbe survive exposure to an antibiotic drug will quickly become dominant throughout the microbial population.     Microbes also often acquire genes, including those that code for resistance, from each other.     The advantage microbes gain from their innate adaptability is augmented by the widespread and sometimes inappropriate use of antibiotics. A doctor, wishing to placate an insistent patient ill with a cold or other viral condition, sometimes inappropriately prescribes antibiotics. Also when a patient does not finish taking a prescription for antibiotics, drug-resistant microbes not killed in the first days of treatment can proliferate.     Hospitals also provide a fertile environment for drug-resistant germs as close contact among sick patients and extensive use of antibiotics force bacteria to develop resistance. Another controversial practice that some believe promotes drug resistance is adding antibiotics to agricultural feed.     For all these reasons, antibiotic resistance has been a problem for nearly as long as we have been using antibiotics. Not long after the introduction of penicillin, a bacterium known as 'Staphylococcus Aureus' ['Staph'] began developing penicillin-resistant strains. Today, antibiotic-resistant strains of S. Aureus bacteria as well as various enterococci-bacteria that colonize the intestines, are fairly common and pose a global health problem in hospitals.     More and more hospital-acquired infections are resistant to the most powerful antibiotics available, Methicillin and Vancomycin, medications reserved to treat only the most intractable infections in order to slow development of resistance to them. This problem seems to be increasing in the US: at present, it is thought that about five to ten percent of patients admitted to hospitals acquire an infection during their stay, and that the risk for a hospital-acquired infection has risen steadily in recent years.     Strains of S. Aureus resistant to methicillin are endemic in hospitals and are increasing in non-hospital settings such as locker rooms. In the past five years, outbreaks of methicillin-resistant S. Aureus infections have been reported among high school football players and wrestlers in California, Indiana, and Pennsylvania.     The first S. Aureus infections resistant to vancomycin emerged in the US approximately three years ago, presenting doctors and patients with a serious problem. Increasing reliance on Vancomycin has led to the emergence of Vancomycin-resistant enterococci infections.     Prior to 1989, no U.S. hospital had reported any vancomycin resistant enterococci, but over the next decade, such microbes have become common, to the point that it is estimated that the incidence of blood and tissue infections known as sepsis has increased three-fold in the past twenty-five years. Moderate Physical Activity Promotes Weight Loss as well as Intense Exercise    Women trying to lose weight can benefit as much from a moderate physical activity as from an intense workout, according to a new study supported by the National Heart, Lung, and Blood Institute [NHLBI], part of the National Institutes of Health.    Prior studies had focused on short-term weight loss. Data were lacking about the optimal degree and amount of physical activity for long-term weight loss. The study - "Effect of Exercise Dose and Intensity on Weight Loss in Overweight, Sedentary Women: A Randomized Trial" - appeared in The Journal of the American Medical Association [JAMA].    The same issue of JAMA also included an article on recreational physical activity and breast cancer risk. The study, based on data from the Women's Health Initiative's Observational Study, found that increased physical activity was associated with a reduced risk for breast cancer in postmenopausal women. Longer duration physical activity gave the most benefit but the physical activity did not need to be strenuous to reduce breast cancer risk.    The exercise dose and intensity trial involved 201 overweight but otherwise healthy women ages 21-45. All received reduced calorie meals in addition to being randomly assigned to one of four physical activity regimens, which varied by intensity and duration. The regimens consisted of either a moderate- or vigorous-intensity physical activity performed for either a shorter [2½ to 3½ hours per week] or longer [3½ to 5 hours per week] duration. The physical activity consisted primarily of brisk walking, and the regimens used about 1,000 or 2,000 kcal per week.    Women in all four groups lost a significant amount of weight [about 13 to 20 pounds] and maintained their weight loss for a year. They also improved their cardiorespiratory fitness. However, the amount of weight lost or fitness improvement was not different among the four groups. Menopause and Hormone Replacement Therapy    What is menopause?... Menopause is the time in a woman's life when menstruation ends; It is part of a biological process that begins, for most women, in their mid-thirties. During this time, the ovaries gradually produce lower levels of hormones, estrogen and progesterone. Estrogen promotes the development of a woman's breasts and uterus, controls the cycle of ovulation [when an ovary releases an egg into a fallopian tube], and affects many aspects of a woman's physical and emotional health.    Progesterone controls menstruation and prepares the lining of the uterus to receive the fertilized egg. 'Natural' menopause begins when a woman has her last period, or stops menstruating, and is considered complete when menstruation has stopped for 1 year. This usually occurs between ages 45 and 55, with variations in timing from woman to woman. Women who undergo surgery to remove both ovaries [oophorectomy] experience 'surgical' menopause, an immediate end to hormone production and menstruation.    During menopause, a woman may experience problems such as hot flashes, night sweats, sleeplessness and vaginal dryness. In addition, some long-term conditions, such as osteoporosis and coronary heart disease, are more common in women in the decades after menopause.    By the time the menopause transition is complete, hormone production has decreased significantly. Even though low levels of estrogen are produced by the adrenal glands after menopause, they are only about one-tenth of the level found in premenopausal women. Progesterone is nearly absent in menopausal women.   [continued] Home  ::  News  ::  Newsletter  ::  Site Map  ::  Exercise & Fitness  ::  Sports Medicine  ::  Nutrition  ::  Cancer Center Breast Cancer  ::  Medical Journals  ::  Mental Health  ::  Alternative Medicine  ::  From NIH  ::  Health Insurance  ::  Drugstore Publications  ::  Guestbook  ::  Download  ::  Shopping  ::  Corporate Services  ::  Digital Content  ::  Q & A  ::  Kids' Corner Women's Health  ::  Testimonials  ::  Bookstore  ::  Privacy  ::  Press Releases  ::  Tell a Friend  ::  Help  ::  About Us The information in our pages is published for educational purposes only and must not be taken as medical advice or medical treatment in any form. For health problems, visitors to our site are encouraged to seek help from licensed, competent physicians.