How do infectious diseases spread in Hospitals and How are outbreaks prevented?

You go to a hospital to get well, but you have to remember that a hospital is one public place that’s bound to be filled with germs, after all, it’s people with germs who wind up there, all kept close together with a staff of caretakers who are almost inevitably going to transmit germs from one of their patients to another.

And we’re not even mentioning the visitors who come in and out dragging all sorts of microscopic organisms along with them. This kind of disease, the kind you pick up in a hospital, is so common that there’s a name for it: nosocomial infection. Of course, nosocomial infection can be avoided, but it’s not easy, and it requires the strict cooperation of everyone from the janitor who mops floors to the surgeon who transplants hearts.

Every doorknob in a hospital is a source of possible transmission of disease, since people touch them and people’s hands are covered with germs. Modern stainless steel doorknobs and doorplates look nice and shiny, but they may be less hygienic than the old-fashioned (and slightly less expensive) brass hardware. Stainless steel, which is 88 percent iron and 12 percent chromium, is a much better place for germs to live than brass, which is about 67 percent copper and 33 percent zinc. Brass, unlike stainless steel, is actually germicidal, even when it’s tarnished. Of course, doorknobs are only one of the places where bacteria can thrive in a hospital.

The recommended procedures for sanitizing patient care areas of hospitals are somewhat involved. Different techniques reflecting different levels of sanitation are used for cleaning medical equipment, housekeeping surfaces, operating rooms, and so on.

Floors of hospitals, for example, don’t need any kind of extraordinary cleaning or disinfecting. Several studies have shown that disinfecting hospital floors has no advantage over simply mopping them with detergent and water. The best approach is to use a technique that doesn’t stir up dust, and to change cleaning solutions and wash cleaning implements often. Letting mops and buckets dry between uses is also helpful, and cleaning solutions should be discarded after use, not saved for reuse. This doesn’t make the floor germ-free, since any floor that has been cleaned immediately becomes contaminated by shoes, the wheels of equipment, body substances, and airborne microorganisms.

On the other hand, areas where immunocompromised patients or newborns are housed require elaborate precautions. Here, surfaces have to be wet-dusted with disinfectants, always making sure to avoid stirring up dust near patients or allowing patients to come in contact with cleaning fluids.

Cleaning equipment that produces mists or aerosols cannot be used in these areas. Vacuuming is a problem, it can spread microorganisms through the air, and has to be done carefully using the right kinds of filters. The filters have to be cleaned and changed regularly, depending on the kind of vacuum cleaners used. Infant beds have to be cleaned and disinfected, and infants frequently moved to clean bassinets or incubators. Any equipment has to be washed thoroughly with water and allowed to dry before being used.

Although there is no evidence that anyone has ever been infected with hepatitis B, hepatitis C, or HIV by contact with a contaminated environmental surface, blood and other bodily fluid spills have to be cleaned and the area promptly disinfected.

HIV is inactivated very rapidly after being exposed to commonly used germicidal agents, including ammonia solutions, and even a 1:100 dilution of ordinary household bleach. Embalming fluids like formaldehyde also completely inactivate HIV and HBV. When large volumes of infected blood or body fluids are spilled, cleanup must be more extensive and decontamination more thorough. In such cases, all organic material must be removed by a person wearing gloves, and a 1:10 solution of bleach is required.

Carpeting in hospitals has advantages (it reduces noise and makes the place a bit more homey), but it’s a good place for bacteria and fungi to grow, and cleaning it can present problems. Its use should be avoided in areas where spills are likely to occur. Vacuuming, both dry and wet, can disperse bacteria into the air, and carpeting is more or less constantly infected with bacteria, even right after cleaning. Some hospitals use carpet tiling, discarding and replacing tiles that have become infected by a spill.

Even flowers can bring unwanted organisms into a hospital room. They can be infested with bacteria when they’re first brought in, and the water in which cut flowers are kept can become a breeding ground for microorganisms of various kinds, usually gram-negative bacteria like Pseudomonas.

Spores of fungi such as aspergilla and fusarium are also commonly found in both fresh-cut and dried flowers. But studies have shown that flowers in a hospital are no more infested with bacteria than flowers in people’s houses, in restaurants, or anywhere else. Flowers are germ-laden wherever they are, but they don’t really pose a problem for patients whose immune systems are working properly.

Even though they are rarely implicated in nosocomial disease outbreaks, cockroaches, flies, and mice are no more welcome in a hospital than anywhere else, and they can be a threat to susceptible patients. Shigella carried by houseflies, for example, may be one cause of diarrhea in pediatric wards, and diarrheal infections are potentially lifethreatening in infants.

Perhaps the biggest threats for infection control in hospitals lies in methicillin-resistant strains of Staphylococcus aureus and vancomycinresistant enterococci. More than half of the staph infections in intensive care units are methicillin resistant, and about a quarter of enterococcal infections are resistant to vancomycin. Although you can find these bacteria on environmental surfaces, that’s not how they are transmitted. They almost invariably go from person to person.

Viruses are a problem everywhere in a hospital, but particularly so in pediatric and neonatal wards. Respiratory viruses including rhinoviruses, respiratory syncytial virus, adenoviruses, influenza viruses, and parainfluenza viruses present significant problems and are usually transmitted by aerosolized small particles or by hand contamination with respiratory secretions.

While most viruses can only persist for a few hours on environmental surfaces, that’s often long enough to transmit them to new victims. Enteric viruses (e.g., rotaviruses, adenoviruses, and caliciviruses) are usually passed along by the fecal-oral route. These affect both patients and staff and are especially troublesome where patients have diarrhea. Careful cleaning of environmental surfaces and frequent hand washing are the only sure ways to prevent spread.

So what’s a poor hospital patient to do? Since washing hands often is one of the best ways to prevent the transmission of germs from one patient to another, some have recommended the direct approach: ask all staff members who approach your bed whether they’ve washed their hands, and don’t let them touch you unless they have.

While some will be comfortable with this, to others it may sound like a good way to infuriate people, especially those who actually have washed their hands, and not a practical method of assuring conscientious care. Of course, if you are under anesthesia or otherwise unable to pose such questions, you just have to rely on the staff assigned to your care.

Other than choosing a hospital with good infection control practices, not always easy for the average person to determine, although every hospital has written guidelines that you can read, you are really at the mercy of the people who are taking care of you.

About Karen Hill

Karen Hill is a freelance writer, editor, and columnist. Born in New York, her work has appeared in the Examiner, Yahoo News, Buzzfeed, among others.

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