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By Larry M. Bush, MD
In recent years, the concept and use of disposable items hasbeen introduced into the hospital setting for the purposes of the prevention ofHAIs, as well as for convenience and cost factors.
The field ofinfectious diseases in the practice of medicine has greatly evolved since itsrecognition as a distinct subspecialty, commencing some time after theadvancement of antimicrobial therapies following World War II. Involvement with diseases such as tuberculosis, malaria,epidemic influenza, and common bacterial and parasitic infections has been andwill continue to be an integral part of this discipline. However, in the ensuingyears, the knowledge base and pervue of the infectious disease practitioner hasbeen required to undergo an extraordinary growth, coinciding with the expansivecomplexities surrounding the diagnoses, treatments and preventions of infectionsboth in and outside of the hospital setting.
In most recent times, the recognition of emerging infectiousdiseases such as Acquired Immunodeficiency Syndrome (HIV/AIDS), lyme disease,hantavirus, West Nile virus, Severe Acute Respiratory Syndrome (SARS), avianinfluenza and Community-Acquired Methicillin-Resistant Staphylococcus aureus (cMRSA)have both threatened the health and well- being of the population and challengedhealthcare providers, perhaps to a greater extent than experienced in past eras.The detection, prevention and treatment of diseases caused by microbes used forbioterrorism purposes has also become an assumed role of those individualsworking in the field of infectious diseases, before and since the anthraxattacks of October 2001.
Antimicrobial resistance among bacterial pathogens has becomea serious health threat, as the incidence of infections with such organisms hasrisen at an alarming rate. MRSA, Vancomycin Resistant Enterococci (VRE),Drug-Resistant Streptococcus pneumoniae (DRSP) and gramnegative bacillipossessing the ability to produce Extended Spectrum Beta- Lactamases (ESBL) havebecome frequent pathogens causing infections in both hospital and communitysettings. This increase in resistance leads to greater morbidity, mortality andcost, and has challenged the medical field and pharmaceutical industry in thedevelopment of prevention and treatment strategies.
The infection control discipline was born in the 1950s,primarily as a response to the problem of staphyloccocal nosocomial infections.Greater than 5 percent of patients admitted to hospitals in our country developa hospital-acquired infection. The estimated cost to the healthcare systemexceeds $5 billion and results in approximately 88,000 deaths per year.
A great majority of these healthcare-acquired infections(HAIs) involve many of the pathogens displaying antimicrobial resistance asdescribed above. The strategies employed to control the spread of HAIs primarilyinclude emphasis on handwashing compliance in conjunction with the use ofdisposable gloves. Hand hygiene remains the single most important measure indecreasing the spread of nosocomial pathogens, as most HAIs are transmitted bycontact via the hands of healthcare workers (HCWs). Other modalities that havebeen found to be effective include transmission-based precautions such ascontact, airborne and droplet isolation. The appropriate choice, timing, andlimitation of the use of antibiotics coupled with the knowledge of resistancepatterns of microbial agents in a particular healthcare institution, strictlyenforced, have been found to decrease the rate of infections caused bymulti-resistant bacterial pathogens. Some facilities have taken to the screeningof patients and the pre-identification of carriers and previously infectedindividuals, as a means to limiting their contact with the general hospitalpopulation. The success of these control measures is variable and under frequentscrutiny.
The approach to disinfection and sterilization of hospitalequipment and patient-care items was developed more than three decades ago andremains in place to this day. This practice involves the categorization of items into those termed critical, semi-criticaland non-critical. Critical items include those devices that pose a high risk ofinfection if they are contaminated prior to being placed in an otherwise steriletissue or vascular space (i.e., surgical instruments, implants, cardiaccatheters and other intravascular devices). Semi-critical objects are thosecoming into contact with non-intact skin or mucosal membranes (i.e., endoscopesand respiratory therapy equipment), whereas non-critical items include thosecoming into contact with intact skin (i.e., blood pressure cuffs, bed rails,linens, bed pans, patient furniture and floors).
While sterilization involves the destruction of all microbiallife on an object or surface using thermal, chemical or pressure methods, theprocess of disinfection typically eliminates most microbes on inanimate objectswith the exception of bacterial spores utilizing a variety of chemical agents.The degree of elimination of organisms by employing disinfection techniques isdependent upon the sensitivity of each population of microbes to the chemicalagent and its time of exposure. As such, disinfection procedures have beenclassified as high-, intermediate- and low-level. High-level disinfectioneliminates all microorganisms with the exception of large numbers of bacterialspores, whereas intermediate-level disinfection destroys mycobacteria,vegetative bacteria, most viruses along with most fungi, but does not guaranteethe eradication of bacterial spores. Lastly, low-level disinfection employsagents which likely will kill the majority of vegetative bacteria, some virusesand fungi, but will not reliably kill mycobacteria nor spores. Alternatively,cleaning is the removal of organic and inorganic material from objects andsurfaces, accomplished by manual or mechanical means with the use of water anddetergents.
The nosocomial pathogens commonly found contaminating thehospital environment vary in their ability to withstand commonly useddisinfection techniques and various disinfectant products, therefore having avariable role in the development of clinical disease. For instance, certainviruses such as influenza, hepatitis B, enteric viruses and the coronavirusassociated with SARS, have been demonstrated to survive on inanimate surfacesand fomites, and can only be effectively eliminated by appropriate disinfection.Spores of Clostridium difficile often colonize commonly used patientarticles such as blood pressure cuffs, furniture and bed pans among others, forlong periods of time, therefore increasing the risk of nosocomial infection inpredisposed individuals. Gram-negative bacilli tend not to spread to patientsfrom the hospital environment as they tend not to be viable after drying. MRSAis frequently encountered on objects in patient rooms; however, proof of fomiteto patient transmission has not been convincingly demonstrated. Nevertheless,these MRSAcolonized objects may serve as major reservoirs for the acquisition ofthese bacterial strains on the hands of HCWs and subsequent spread to theirpatients. The role of VRE in hospital fomite contamination depends upon theproximity of the environmental site to the patient carrying this organism;therefore these bacteria may be transmitted by both indirect (via HCWs hands)and direct contact with colonized surfaces and fomites that have not beenproperly disinfected.
Much controversy exists regarding the spread of nosocomialinfections in relation to the role of contamination of surfaces and equipmentcommonly encountered in the immediate patients hospital environment. Although surveillance cultures have shown bacterialcontamination of such inanimate items, its clinical significance remainsunclear. Some factors that have been suggested to help possibly establish acausal relationship between hospital environment contamination-colonization andHAIs include:
In recent years, the concept and use of disposable items has beenintroduced into the hospital setting for the purposes of the prevention of HAIs,as well as for convenience and cost factors. Such items include: blood pressurecuffs, thermometers, stethoscopes, pulse oximetry devices, bed pans andpersonal-hygiene items, among others.
One object, perhaps not yet considered as a potentialreservoir for nosocomial pathogens, is the television remote control devicealmost universally connected to the nurse call button attached to the hospitalbed by a cord. Although not previously studied, one can presume that this objectmay also be colonized to various degrees with many of the microbial organismsimplicated in nosocomial infections, not unlike other surfaces or fomites in thepatients room. Moreover, the television control systems presently used maynot be amenable to be sufficiently disinfected due to limitations imposed by theintrinsic nature of the device. Television control pads are one of the mostoften manipulated objects in the patients room; therefore, if the frequencyand duration of contact with a colonized inanimate object has a directcorrelation with the risk of transmission of a pathogenic organism, then thisdevice may be an important potential source of hospital-acquired patientcolonization and/or infection.
In line with this concept of single-use hospital items, adisposable, inexpensive remote control has been developed that operates all ofthe televisions in patients rooms within any one particular hospital withoutthe need for programming. These individually wrapped remote controls have beencreated to help in potentially reducing the risk of acquisition of nosocomialpathogens. Though studies regarding the role of colonized hospital environmentalobjects are limited and inconclusive, the idea of the use of disposabletelevision remote controls is in keeping with the already implemented currentpractices. Any decrease in potential nosocomial infections may represent costsavings which far outweigh the expense incurred by the use of disposable items.
As the scope of hospital infection control evolves due toemerging infections, bloodborne pathogens, antimicrobial resistance and biologicagents used for the purpose of terrorism, ongoing strategies to reduce the riskof HAIs need to be developed, studied, and implemented. Disposable devices inthe hospital setting perhaps should be considered part of these infectioncontrol measures.
Larry M. Bush, MD, is a board-certified infectious diseasephysician in the West Palm Beach, Fla. area. He is a graduate of the Universityof Pennsylvania and the Medical College of Pennsylvania, both in Philadelphia. He is an affiliate clinical associate professor in theDepartment of Biomedical Science at Florida Atlantic University in Boca Raton,Fla., as well as a voluntary assistant professor of medicine at the Universityof Miami School of Medicine. Along with having authored various articles andbook chapters in the field of infectious diseases, Bush was directly involvedwith diagnosing the index case of anthrax bioterrorism in October 2001. Hecurrently serves as chairman of infection control at three local hospitals inthe area where he practices.