In recent years, it has become fashionable in the media to warn of the exotic new infectious diseases percolating in faraway lands. The gruesome Ebola virus, which swept through Zaire three years ago, has captured the public imagination in books and on film. But while Hollywood has been busy making scary movies, infectious-disease experts know that the bigger danger is in our own backyard: garden variety germs that for decades have been so easily felled by antibiotics that most people, including some scientists, naively assumed they were no longer a threat.

For the past decade, however, scientists at the Federal Centers for Disease Control and Prevention in Atlanta and all over the world have been sounding alarm bells about the growth of antibiotic resistance, a problem that has been fueled by patients who demand antibiotics for every bout of the sniffles and by doctors who give in to such demands. The list of dangerously virulent drug-resistant microbes is growing all the time: streptococcus pneumoniae, which causes pneumonia, childhood ear infections and meningitis; mycobacterium tuberculosis, which causes TB, and neisseria gonorrhoeae, which causes gonorrhea.

But none are as frightening to medical experts as the VISA strains of staph. Within the past 18 months, the C.D.C. has documented the first four cases ever, the most recent being that of the New York detective. Their emergence is an ominous harbinger of what Dr. Stuart B. Levy, director of the Center for Adaptation Genetics and Drug Resistance at Tufts, calls ''the worst thing that could happen in clinical infectious disease.''

One reason for concern is that staph is a particularly common and robust organism; it lives on the skin and in the nostrils of otherwise healthy people as part of what scientists call the ''natural flora,'' where it is relatively harmless. But if it gains access to the body through scrapes, cuts or surgical incisions, as it often does, it can cause a range of ailments, from pus-oozing cuts to sepsis, an often lethal infection of the bloodstream. Children who scrape their knees are susceptible to staph, as are housewives who cut their hands in the kitchen or anybody else with an open wound. Should VISA strains become common, simple cuts and scrapes could become mortal wounds.

To complicate matters, hospitals are already breeding grounds for a host of dangerous bugs. Each year, nearly 90,000 patients in the United States die of a hospital-acquired infection, and many of those cases are theoretically treatable with antibiotics. Staph is often the culprit, picking on vulnerable patients like the elderly, the immunocompromised and those undergoing surgery. The emergence of an untreatable strain of staph would put virtually any healthy person at risk, and could turn a bad situation into a disastrous one. As Levy says, ''Right now, we are still in most cases able to use vancomycin. Now let's say we lose vancomycin. Where are the deaths going to go? They're going to go up. This number could double.''

Now that these bugs are figuring out ways to evade the very miracle drugs that have always worked so well against them, there is little on the horizon to keep the virulent new supergerms in check. Joshua Lederberg, a Rockefeller University professor who is widely regarded as one of the nation's leading authorities on infectious disease, warns that far too little attention is being paid to the threat of drug-resistant germs. ''The odds of Ebola breaking out are quite low, but the stakes are very high,'' Lederberg says. ''With antibiotic resistance, the odds are certain and the stakes are just as high. It is happening right under our noses.''

And it is happening at a particularly precarious moment, when many hospitals are cutting back on services as they struggle to survive the changing economics of health care. United Hospital in Port Chester, for example, reflecting national trends, plans to ''outsource'' Rotun's lab. Meanwhile, drug manufacturers, which in the early 1980's all but abandoned development of new antibiotics on the theory that they were no longer needed, find themselves behind the curve; they are hustling to invent new treatments and put them on pharmacy shelves. And that is why the emergence of the vancomycin-resistant strains is viewed as such a worrisome public health threat. The next generation of new antimicrobials is, by the industry's own estimate, at least several years away, creating a dangerous window in which the virulent new microbes might be able to spread unchecked. If that happens, modern medicine might revert to the days before penicillin, when sore throats could become fatal and patients who walked into the hospital for routine surgery might be carried out in coffins.