While methicillin-resistant Staphylococcus aureus (MRSA) infections have largely been hospital-acquired infections (HAIs), for the past several years practitioners in the outpatient surgery arena have been on guard against community-acquired MRSA (CA-MRSA) infections that could make their way into ambulatory surgery centers (ASCs). Hospital-based emergency departments are witnessing an increase in MRSA skin and soft tissue infections that has been a decade in the making, underscoring the need for physicians and allied professionals to appropriately identify and treat MRSA infections in outpatient facilities.
Persons with MRSA infections who meet all of the following criteria likely have CA-MRSA infections:
- Diagnosis of MRSA was made in the outpatient setting or by a culture positive for MRSA within 48 hours after admission to the hospital.
- No medical history of MRSA infection or colonization.
- No medical history in the past year of hospitalization; admission to a nursing home, skilled nursing facility or hospice; dialysis; or surgery.
- No permanent indwelling catheters or medical devices that pass through the skin into the body.
More recently, HA-MRSA infections were further classified as either “community-onset” (cases with a healthcare risk factor but with a positive culture obtained less than 48 hours after hospital admission) or “hospital-onset” (cases with positive culture obtained more than 48 hours after admission, regardless of whether they also had other healthcare risk factors).
Naimi, et al. attempted to characterize the epidemiological and microbiological characteristics of CA-MRSA cases compared with healthcare-associated (HA) MRSA cases in a prospective cohort study of patients with MRSA infection identified at 12 Minnesota facilities from January through December 2000. The researchers found that of 1,100 MRSA infections, 131 (12 percent) were community-associated and 937 (85 percent) were healthcare-associated; 32 (3 percent) could not be classified due to lack of information. Skin and soft tissue infections were more common among community-associated cases (75 percent) than among healthcare-associated cases (37 percent). Although community-associated MRSA isolates were more likely to be susceptible to four antimicrobial classes, most community-associated infections were initially treated with antimicrobials to which the isolate was non-susceptible. Community-associated isolates were also more likely to belong to one of two pulsed-field gel electrophoresis clonal groups in both univariate and multivariate analysis. Community-associated isolates typically possessed different exotoxin gene profiles (e.g., Panton Valentine leukocidin genes) compared with healthcare-associated isolates. Naimi, et al. concluded that because CA-MRSA and HA-MRSA cases differ demographically and clinically, with their respective isolates being microbiologically distinct, it suggests that most CA-MRSA strains did not originate in healthcare settings, and that their microbiological features may have contributed to their emergence in the community.
Controlling MRSA infections in the community is challenging, since as much as 30 percent of the population is colonized with staph bacteria and up to 1 percent is colonized with MRSA, according to the Centers for Disease Control and Prevention (CDC). While most staph skin infections are minor and can be treated, the more serious infections manifest as surgical wound and bloodstream infections.
Factors that have been associated with the spread of MRSA skin infections include close skin-to-skin contact, openings in the skin such as cuts or abrasions, contaminated items and environmental surfaces, crowded living conditions and poor hygiene. The main mode of transmission of staph and/or MRSA is via hands which may become contaminated by contact with a) colonized or infected individuals, b) colonized or infected body sites of other people, or c) devices, items or environmental surfaces contaminated with body fluids containing staph or MRSA. Other factors contributing to transmission include skin-to-skin contact, crowded conditions and poor hygiene.
Persistence of Pathogens on Environmental Surfaces
The jury is still out in terms of industry agreement on the degree to which the healthcare environment serves as a reservoir for a variety of infectious microorganisms. In its 2003 guidelines addressing environmental infection control in healthcare facilities, the Healthcare Infection Control Practices Advisory Committee (HICPAC) of the Centers for Disease Control and Prevention (CDC) notes that this environment “is rarely implicated in disease transmission except in the immunocompromised population.” However, HICPAC adds, “Inadvertent exposures to environmental opportunistic pathogens or airborne pathogens may result in infections with significant morbidity and/or mortality. Lack of adherence to established standards and guidance can result in adverse patient outcomes in healthcare facilities.”
There is no dispute that proper, effective surface cleaning and disinfection in healthcare facilities is one of the most important ways to prevent and control HAIs. In light of recent studies that point to the persistence of some bacteria, viruses and fungi, surface cleaning in the healthcare environment takes on a new sense of urgency. Researchers examined the persistence of different nosocomial pathogens on inanimate surfaces and reported that these microorganisms may survive, even thrive on surfaces for months and can be a continuous source of transmission if no regular preventive surface cleaning and disinfection is performed.
Researchers found that most gram-positive bacteria, such as, Staphylococcus aureus (including methicillin-resistant), survive for months on dry surfaces. Many gram-negative species, such as, Escherichia coli, can also survive for months. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans, a significant nosocomial fungal pathogen, can survive up to four months on surfaces.
The researchers also found that most viruses from the respiratory tract, such as can persist on surfaces for a few days. Viruses from the gastrointestinal tract persist for approximately two months. Bloodborne viruses, such as hepatitis B virus (HBV), can persist for more than one week. Herpes viruses have been shown to persist from a few hours up to seven days.
Eliminating Cross-Contamination
Proper cleaning and disinfection of environmental surfaces in the healthcare setting is critical to infection prevention strategies in ASCs, regardless of the traditionally low infection rates in these facilities. With contaminated high-touch surfaces serving as a reservoir of pathogenic microorganisms, healthcare professionals should practice routine cleaning regimens as outlined by the CDC in its Guidelines for Environmental Infection Control in Healthcare Facilities (2003). Coupled with proper hand hygiene, cleaning and disinfecting protocols can help to minimize the transfer of microorganisms that can occur via hand contact between contaminated surfaces and patients.
The number and types of microorganisms present on environmental surfaces are influenced by the number of people in the environment, amount of activity, amount of moisture presence of material capable of supporting microbial growth, rate at which organisms suspended in air are removed, and the type of surface and orientation.
To review, the CDC recommends the following as cleaning and disinfecting strategies for environmental surfaces in patient-care areas:
- Select EPA-registered disinfectants, if available, and use them in accordance with the manufacturer’s instructions. According to the CDC guidelines, environmental surface germicides should specify (via labels, technical data and/or product literature) indications for product use and provide claims for the range of antimicrobial activity, according to regulations established by the Environmental Protection Agency (EPA).
- Do not use high-level disinfectants/liquid chemical sterilants for disinfection of either non-critical instruments and devices or any environmental surfaces.
- Follow manufacturers’ instructions for cleaning and maintaining non-critical medical equipment. In the absence of a manufacturer’s cleaning instructions, follow these procedures:
Clean non-critical medical equipment surfaces with a detergent or disinfectant. This may be followed by an application of an EPA-registered hospital disinfectant in accordance with germicide label instructions.
Do not use alcohol to disinfect large environmental surfaces.
Use barrier protective coverings as appropriate for non-critical surfaces that are touched frequently with gloved hands; likely to become contaminated with blood or body substances; or are difficult to clean.
- Keep housekeeping surfaces such as floors, walls and tabletops visibly clean on a regular basis and clean up spills promptly. Use a one-step process and an EPA-registered hospital detergent or disinfectant designed for general housekeeping purposes in patient-care areas where uncertainty exists as to the nature of the soil on the surfaces, or regarding the presence of multidrug-resistant organisms on surfaces. Detergent and water are adequate for cleaning surfaces in nonpatient-care areas.
- Clean and disinfect high-touch surfaces such as doorknobs, bed rails, light switches and surfaces in and around toilets in patient-care areas on a more frequent schedule than minimal-touch housekeeping surfaces.
- Avoid large-surface cleaning methods that produce mists or aerosols, or disperse dust in patient-care areas.
- Follow proper procedures for effective uses of mops, cloths and solutions, including:
Prepare cleaning solutions daily or as needed, and replace with fresh solution frequently according to facility policies and procedures.
Change the mop head at the beginning of each day and also as required by facility policy, or after cleaning up large spills.
Clean mops and cloths after use and allow them to dry before reuse; or use single-use mop heads and cloths.
After the last surgical procedure of the day or night, wet-vacuum or mop operating room floors with a single-use mop and an EPA-registered hospital disinfectant.