2005 in review: Bugging out? Waiting for the pandemic
BY MITZI BAKER
In the never-ending battle of man vs. microbe, chalk up 2005 as a good one for the bugs.
Cases of antibiotic-resistant bacteria cropped up, some of which are the flesh-eating variety. A man in New York developed a case of HIV that was resistant to all the commonly used antiretroviral drugs and rapidly progressed to AIDS. Concerns about the threat of bioterrorism continued. And the specter of an avian flu pandemic provoked near hysteria.
While we have developed many vaccines and drugs over the previous decades to stop infectious diseases, microbes are constantly evolving into new forms that can withstand the medications.
That resistance became all too apparent earlier this year through research findings on the prevalence of Staphylococcus aureus, often referred to simply as "staph," that can defy the latest antibiotics. What was essentially a nonexistent problem a few years ago is now one of the leading causes of the estimated 2 million infections and 88,000 deaths among people who get infected in a hospital. Ellen Jo Baron, PhD, director of the medical center's Clinical Microbiology and Virology Laboratories, has been tracking the rise of antibiotic-resistant staph with scientists at other Bay Area hospitals. "We need new antibiotics, ones that work in different ways to circumvent the ongoing resistance problem," she said earlier this year.
Viruses such as HIV are also continuing to develop resistance to the drugs used to combat them. In February, public health officials in New York City sent out a nationwide alert that they had detected in one man a rare strain of the HIV virus that is resistant to virtually all retroviral drugs and led to the rapid onset of AIDS. To assess the threat of this virus, reporters and scientists turned to Robert Shafer, MD, assistant professor of medicine (infectious diseases and geographic medicine), who maintains the Stanford HIV Drug Resistance Database. "I suspect, and hope, that we are not witnessing the emergence of a 'superbug,' but rather a combination of two uncommon unfortunate events: the transmission of a highly drug-resistant virus to a highly susceptible individual," said Shafer. "This case could serve as a wake-up call to re-emphasize the need for reducing high-risk behaviors and for increasing testing for HIV."
Adding to the concerns raised by mutations of existing viruses is the thought that terrorists might reintroduce past killers that had been thought extinct. "It is not true that smallpox is totally gone," said Jose Montoya, MD, associate professor of medicine in the Division of Infectious Diseases and Geographic Medicine, who conducted a clinical trial comparing smallpox vaccines. Although the last natural case occurred in Somalia in 1977, he noted in January, "Stockpiles still exist and the threat of bioterrorism, while always present, is heightened after Sept. 11." Smallpox virus is considered one of the most lethal biological weapons because it kills about 30 percent of those infected and is easily transmitted.
Yet such concerns pale when compared with the recent reports speculating about an outbreak of avian flu. "In the event of an avian influenza pandemic, almost the entire human population is at risk," said professor of pediatrics David Lewis, MD, last month. He is beginning a study of avian flu vaccine. "We know it's only a question of time before we will face a pandemic from a new flu strain."
Lest it all sound too discouraging, remember that microbes aren't all bad. In fact, many of them play a beneficial role, assisting with nutrient processing, storing fat and protecting against pathogens, which are often cases of good microbes gone bad.
A striking example of the dual nature of a microbe was published in March on Helibacter pylori, the organism that also earned two researchers the Nobel Prize this year. Although H. pylori has been implicated as a culprit in causing stomach cancer and ulcers, Catherine de Martel, MD, showed that being infected with the bug might offer protection against a type of esophageal cancer. "It is truly a bad bug, but what we show is that it is not a bad bug in all people," said de Martel.
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