Infection Control Today - 10/2003: Invisible Intruders


Invisible Intruders
Inanimate Objects Role in Nosocomial Infection

By Kathy Dix

In a healthcare setting, we are surrounded by thousands of non-living objects that can nonetheless harbor pathogens. Admitting there is a problem is just the first step. There are so many places where pathogens can set up camp that its nearly impossible to list them all. But each area of the facility has its own Achilles heels.

In all of these areas are doors and door handles or knobs, floors and walls. As healthcare workers (HCWs) move throughout the healthcare facility, they see risks specific to the setting:

The Waiting Room

This area contains chairs, coffee tables, magazines and newspapers that are passed from one hand to another. Your visitors may be healthy and in for a checkup; they may be ill and carrying a contagious disease cold, flu, severe acute respiratory syndrome (SARS) or norovirus.

Furniture is thought to be lower-risk than other items, but, surprisingly, the Centers for Disease Control (CDC) notes that vancomycin- resistant enterococcus has had prolonged survival on chairs and other environmental surfaces.1

The Restroom

Toilets, sinks, faucets and flushing handles, paper towel dispensers and stall doors are all potential harbors for pathogens. In addition, sinks here and in patient rooms that are too shallow may harbor bacteria in the drain, and they should be large enough to prevent splashing.

Restrooms especially are the perfect setting to pass along germs; hands-free bathroom fixtures can help eliminate the problem by incorporating sensor-operated toilets and faucets, and paper towel dispensers that dont require contact with the dispenser.

The Pre-Op and Recovery Room

Here, patients may receive sedatives or pain medication via IVs. They may be hooked up to monitoring equipment, and theyre certainly lying on beds or gurneys.

The OR

It is fortunate that the operating room (OR) is a sterile environment because it may be filled with the largest number of potentially-infectious objects: instruments, the back table, the surgical table, monitoring/ anesthesia equipment and drapes.

The Nurses Station

Although patients do not use this space, it is a staging area for their caregivers, often with a computer and keyboard, mouse, monitor, charts, writing instruments and a counter/desk surface.

The Patient Room

Here, the compromised patients recuperate, surrounded by furniture, IV stands, sinks, private restrooms, telephones and monitoring or support equipment.

Clearly, there are plenty of places for pathogens to hide.

Certain elements are less acceptable in the hospital setting carpets, for example. Carpets can be very welcoming hosts to pathogens; microbes can be found in greater numbers here than on other flooring. Therefore, carpets should be vacuumed daily and periodically steam cleaned, says the CDC. Carpeting should be avoided in highrisk areas because the cleaning process may aerosolize fungal spores.

In addition to the furniture and the carpet, other items have been found to harbor VRE and methicillin-resistant staphylococcus aureus (MRSA), such as privacy curtains, scrub suits and plastic aprons.

So many items in the facility are vulnerable to contamination with pathogens, at least transiently, says Ginnie Abell, RN, BA, CIC, director of infection control and clinical safety at Summa Health System. The scenario is that the hand that touches the doorknob that then touches the patients open wound could transmit this organism, she says.

But certain inanimate objects or surfaces are more of a risk than others. When we talk about organisms and inanimate objects, we have to think about the most at-risk things, which are without a doubt the horizontal services. The horizontal surfaces by definition are more able to hang on to organisms. And when we talk about inanimate objects, we have to talk about the type of microorganisms. It would seem that the gram-negative microorganisms have more of a propensity for hanging around on the environmental surfaces. Its because it takes very little organic matter to sustain the gram-negatives for some amount of time. A very little bit of organic material, whether that be sputum, or a little bit of fecal material the gram negative organisms can sustain themselves for some amount of time in very little, she adds.

Gram-negative organisms in particular have a tendency to linger because theyve adapted themselves so well to the human gastrointestinal tract, says Abell. On the other hand, although we have in the past demonstrated that organisms like Staphylococcus aureus can become airborne through a coughing mechanism and can then colonize other peoples nares, we find very little evidence of that in the gram-negative field. So thats the good news for gram-negatives that they dont become airborne.

Gram-positive organisms, however, are a different story. These are not in the category of communicable diseases, but rather in the category of opportunistic pathogens ... for the very sick who are instrumented in every orifice of their bodies, those organisms find a portal of entry into the body so easily, as opposed to communicable disease organisms like the flu bug, the influenza A and B organisms, the common cold organism, says Abell.

These airborne organisms are easily transmitted from person to person, healthy or ill. Usually, those communicable disease organisms have to be inhaled, to cause a problem, Abell continues. You cant inhale off of inanimate objects. TB (tuberculosis) needs to be expelled into the air and then inhaled. Once the TB organism falls to the environmental surface, it is by definition ineffective. The gramnegatives, although they arent going to cause a healthy person problems, can be transmitted simply by getting the organism on your hand, putting the organism onto the endotracheal tube, or the catheter of a compromised patient.

The susceptibility of compromised patients makes environmental cleaning all the more important the daily cleaning to keep the load of microorganisms as low as possible, Abell says. We can do this, and we know that we can do this. We can maintain sterile technique within the operating room; more and more we have to maintain medically-aseptic technique within each patients room, meaning you go into the room, you wash your hands, you put your gloves on, and you do your procedure at the patients bedside without ever touching anything with your gloves on that could represent contamination.

But the more intense the patient care, the more difficult it is to maintain the best of techniques, she says. Healthcare workers must practice, practice, practice, and look to whether a surveillance of infection in any unit will clue you rapidly if youre getting into a problem ... If you have a patient with a resistant organism, youll put that person directly into multi-drug resistant organism (MDRO) precautions, which is more than just standard precautions. It is certain techniques of gloving and gowning, and maintaining equipment within the room so that you dont transmit that organism farther.

If another patient acquired the MDRO, universal gloving procedures and MDRO precautions might be necessary for the entire unit. Even if you didnt know the exact status of every patient, you would assume that every patient could have a multi-drug resistant organism, Abell affirms.

Because universal precautions are so intensive, they are necessary only in certain patient cohorts, such as critical care units and units with ventilator patients. Thats because its the most instrumented of patients that get into trouble with MDROs. The patients have tubes compromising their own natural defenses, says Abell.

When asked if antimicrobial coatings are a good defense, Abell expresses discomfort with the idea. Im not a big proponent, although I think that there are many disinfectants that have done what is commonly called residual kill ... The ones Im most comfortable with are the chlorhexidines, and they are in the category of aseptic surgical preps for the human body, as opposed to on inanimate surfaces. I think the EPA approves disinfectants if used properly, and if used at the appropriate intervals, so I would not describe them as having residual kill; I would describe them as keeping the bacterial load to a low level by using them properly at the proper intervals.

And Abell has no doubt that such coatings can help breed resistance. Even those things that dont claim particular residual kill ... but just the use of antimicrobials in the home setting [generates the] discussion of, Does this promote the growth of resistance? Now, people who manufacture the antimicrobials say Oh no, the type of antimicrobial used, and the mechanisms by which it was developed, does not contribute to resistance. Im not convinced. I think that environmental cleaning should be based on using an appropriate product to lessen the number of microbes there, and to use it at an appropriate intervals, and youll stay out of trouble.

Norman Miner, director of research at MicroChem Laboratory, also disapproves of antimicrobial coatings, but believes that they do have their place nonetheless. Urinary catheters are semi-critical items, and data indicates that when they are impregnated with antimicrobial silver ions, there are fewer urinary tract infections, Miner says. Otherwise, in my opinion, the impregnation of antimicrobial chemicals into plastic items does not kill microbes, and such items arent much of a threat to hospital infections in the first place.

When asked if antimicrobial coatings assist in creating resistance to pathogens, Miner replies, The antimicrobials that might be used in or on the materials of inanimate surfaces do not contribute to resistance. Resistance is a result of antibiotics and point mutations. Focus on what is important: sterilization of critical items; careful cleaning, high level disinfection, thorough rinsing with sterile water and proper storage (dry storage) of semicritical items; hand washing with an alcohol antiseptic; and routine disinfection of non-critical environmental surfaces.

The reason why antimicrobial-coated surfaces are ineffective is simple: Because antimicrobial chemicals and microbes need a solution (like water) to be able to swim together to meet each other. Swimming in plastic is very inefficient, Miner explains. Items of threat are hands, and any medical device that touches one patient and then touches another patient, but these devices have degrees of danger. For example, a flexible colonoscope or gastroscope that touches the mucous membranes of one patient is a greater danger to the next patient than a wheelchair, for obvious reasons. Thus, these two devices get disinfected between patients in different ways. The endoscope gets cleaned and disinfected very carefully and thoroughly, and the wheelchair gets cleaned and disinfected in a simpler manner.

Of course, cleaning inanimate objects must be done on a regular schedule, and patient rooms, at least, should be cleaned on a timetable much like that of a hotel.

The room should be cleaned after one customer (patient) leaves and before the next patient arrives, or some other schedule similar to housekeeping, if the patient stay is long-term, says Miner.

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