Concerns on the Infection Prevention Limitations of Standard Precautions

By Peter Teska and Jim Gauthier

The Standard Precautions concept in healthcare dictates that healthcare workers assess risk in advance of a patient interaction and use appropriate interventions such as barriers, hand hygiene, and/or surface disinfection, to address the risk and prevent becoming contaminated by the patient or the patient’s environment. This approach has generally been credited with helping hospital employees protect themselves from acquiring infectious agents on a daily basis. However, a growing body of research has called into question whether this approach is in fact adequate.

Recent Research
Creamer (2010) looked at hand contamination rates with methicillin-resistant Staphylococcus aureus (MRSA) for healthcare workers. In the study, hands sampled after glove use did not test positive for MRSA, regardless of whether hand hygiene was performed or not. For hands tested when no gloves were worn, 1 of 59 were positive for MRSA after using alcohol hand gel, 7 of 210 were positive after hand washing and 2 of 35 were positive when using a chlorhexidine product. In total, 10 of 304 samples, or 3 percent, were positive.

Roughmann (2015) looked at long-term care and glove/gown contamination in an environment where 28 percent of residents were colonized with MRSA. While gowns (14 percent) and gloves (24 percent) were predictably contaminated after interactions with the residents (which averaged 7 interactions per monitored event), 5 percent of gowns/gloves were contaminated with MRSA from non-colonized residents. This implies either that these residents were colonized, but it was either not detected through nasal and perianal swabbing, the colonization occurred after initial testing, or that the colonized residents have spread MRSA into reservoirs around non-colonized residents, allowing them to be transiently colonized.

Bonifat (2015) tested the air during a norovirus outbreak to see if viable virus could be detected. The air contamination rate was 2000 genomes per cubic meter of air. Since the average person breathes 6 liters of air per minute, a healthcare worker could inhale 60 genomes in a five minute interaction even with no patient contact. As norovirus is extremely infectious (Hall, 2012), this dose is likely to be infectious for some employees. The article did not indicate that there was active vomiting or aerosol generating procedures when the sampling occurred, implying that there is some level of air contamination even in the absence of gross soiling for a pathogen generally considered to be transmitted via contact routes of exposure.

Key Issues
These articles support three points that are important to this discussion.
1. In many cases, healthcare workers cannot properly assess the risk of contamination prior to patient interaction because there are not al-ways cues available for them to identify risk.
2. Use of barriers can only be correctly performed if the healthcare worker understands the organisms likely to be encountered and the mode of transmission.
3. Even when an employee performs hand hygiene, there is some level of risk that they will not have removed all the pathogens from their hands even if following the generally accepted hand hygiene methodology (15 seconds of lathering for soap and water, 15–30 second contact for alcohol-based handrub).
When a patient has been diagnosed with a specific infection or the patient is clearly contaminating their environment (respiratory leakage, diarrhea, etc.), there are cues for the healthcare worker to make them aware of the need to use barriers. But when the patient is colonized (with no visible symptoms), or if the patient has become transiently colonized by being in the environment of an infected patient, these cues are absent. If the Creamer study is representative of healthcare practices, then there are likely numerous examples of hospital employees becoming contaminated and staying contaminated after performing hand hygiene.
If a healthcare worker knows to use barriers (diagnosis, visible symptoms, activity to be performed), there is a strong probability that proper use of barriers can interrupt the chain of transmission. However, when dealing in an environment with a colonized patient, the Roughmann study indicates that that workers are likely becoming contaminated, even when not dealing directly with the colonized patient.
As we rely on hospital employees to know the proper moments for hand hygiene and the proper technique to perform hand hygiene, we assume that after properly performing hand hygiene, their hands are free of contamination. However, the Creamer study suggests that workers’ hand hygiene techniques may not remove all of the contamination. If some percentage of the time (3 percent in this case), hand hygiene is not removing all of the contamination on hands, we should be concerned not just with the frequency of hand hygiene, but also with the quality of hand hygiene, including factors such as the areas of the hands contacted during hand hygiene and the duration of hand hygiene. Hand hygiene auditing should provide not only feedback on the moments being audited, but also on substandard technique.
Implications
Standard Precautions is generally recognized as being a bundle of interventions that prevents significant harm to health for both healthcare workers and patients, but it may not always be effective. Further research into the issues discussed here may be needed to better understand the risks involved. The research should focus on the following areas:
1. When a patient has an unknown colonization status, how frequently are they carrying pathogens of concern on their person and how easily can these pathogens be transmitted to employees through casual or healthcare-related contact? Is hand hygiene alone adequate to protect the employee?
2. When performing hand hygiene (either handwashing or the use of alcohol-based handrub) how heavily are hands contaminated with potential pathogens and at what levels do potential pathogens remain after the hand hygiene event?
3. For pathogens generally associated with transmission via contact, can testing of the air around the patient detect a pathogen at levels that could cause infection? If detected at levels that can cause infection, might this imply that the pathogen can be transmitted via droplet or possibly airborne routes? Further, can this transmission either directly infect the healthcare worker through direct contact with mucous membranes (eye, nose or mouth) or possibly contaminate surfaces on or around the worker (e.g., their clothing), allowing an indirect contact self-inoculation of mucous membranes resulting in an infection?

Peter Teska is a global infection prevention application expert with Sealed Air’s Diversey Care division and can be reached at peter.teska@sealediar.com. Jim Gauthier is a senior clinical advisor with Diversey Care and can be reached at james.gauthier@sealedair.com.

References:

Creamer E, et al. When are the Hands of Healthcare Workers Positive for Methicillin-resistant Stapylococcus aureus? J Hosp Infect, 2010; 75: 107-111.

Roghmann, et al. Transmission of Methicillin-Resistant Staphylococcus aureus (MRSA) to Healthcare Worker Gowns and Gloves During Care of Nursing Home Residents. Infect Control Hosp Epidemiol, 2015; 36: 1050-1057.

Bonifait, et al. Detection and Quantification of Airborne Norovirus During Outbreaks in Healthcare Facilities. Clin Inf Dis, 2015; 61: 299-304.

  Hall AJ. Noroviruses: The Perfect Human Pathogen? J Infect Dis 2012;205:1622-4.