Is there any evidence that routinely wearing gowns and gloves upon entry into the rooms of patients on contact precautions for MRSA or VRE really works?

Although routine gowning and gloving in the care of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE)—also known as contact precautions (CP)— is considered a standard of care (1), the evidence supporting its effectiveness in preventing endemic hospital-associated multidrug-resistant organism (MDROs) infections is not robust and is often conflicting. In fact, this practice is increasingly being questioned (including by some hospital epidemiologists) as means of preventing endemic transmission of MDROs in hospitals (1-7).
Critics often point out that studies supporting the use of CP in MDROs are observational, involving only outbreak situations where they were instituted as part of a bundled approach (eg, improved hand hygiene), making it difficult to determine its relative contribution to infection prevention (2,6).
In fact, recent cluster-randomized trials have largely failed to demonstrate clear benefit of CP over usual care for the prevention of acquiring MRSA or VRE in hospitalized patients (2,4). Furthermore, a meta-analysis of studies in which CP were eliminated failed to find an increase in the subsequent rates of transmission of MRSA, VRE, or other MDROs (2,7).
Based on these and other studies, some have suggested that in the presence of other infection prevention measures (eg, hand hygiene monitoring), CP be implemented only in select circumstances such as open or draining wounds, severe diarrhea or outbreak situations (3).


The United States Centers for Disease Control and Prevention (CDC), along with the Infectious Diseases Society of America (IDSA) and the Society of Healthcare Epidemiologists of America (SHEA), however, continue to recommend implementation of CP in the care of patients with MDROs.  


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1. Maragakis LL, Jernigan JA. Things we do for good reasons: contact precautions for multidrug-resistant organisms, including MRSA and VRE. J Hosp Med 2019;14:194-6.
2. Young K, Doernberg SB, Snedcor RF, et al. Things we do for no reason:contact precautions for MRSA and VRE. J Hosp Med 2019;14:178-80.
3. Bearman G, Abbas S, Masroor N, et al. Impact of discontinuing contact precautions for methicillin-resistant Staphylococcus aureus and vancomyin-resistant Enerococcus: an interrupted time series analysis. Infect Control Hosp Epidemiol 2018;39: 676-82.
4. Harris AD, Pineles L, Belton B, et al. Universal glove and gown use and acquisition of antibiotic-resistant bacteria in the ICU. A randomized trial. JAMA 2013;310:1571-80.
5. Morgan DJ, Murthy R, Munoz-Price LS, et al. Reconsidering contact precautions for endemic methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. Infect Control Hosp Epidemiol 2015;36:1163-72.
6. Morgan DJ, Wenzel RP, Bearman G. Contact precautions for endemic MRSA and VRE. Time to retire legal mandates. JAMA 2017;318:329-30.
7. Marra AR, Edmond MB, Schweizer ML, et al. Discontinuing contact precautions for multidrug-resistant organisms: a systematic literature review and meta-analysis. Am J Infect Control 208;46:333-340.

Is there any evidence that routinely wearing gowns and gloves upon entry into the rooms of patients on contact precautions for MRSA or VRE really works?

Should I routinely select antibiotics with activity against anaerobes in my patients with presumed aspiration pneumonia?

Anaerobes have been considered a major cause of aspiration pneumonia (AP) based on studies published in 1970’s (1-3). More recent data, however, suggest that anaerobes no longer play an important role in most cases of AP (4-7) and routine inclusion of specific anti-anaerobic drugs in their treatment is no longer necessary.

An important reason for anaerobes not playing an important role in AP in the current era is the change in the demographics of patients who may be affected. Patients reported in older studies often suffered from alcohol use disorder, drug ingestion, seizure disorders and acute cerebrovascular accident. In contrast, more recent data show that AP often occurs in nursing home residents, the elderly with cognitive impairment, and those with dysphagia, gastrointestinal dysmotility or tube feeding (8,9).

In addition, many cases of AP reported in older studies involved delay of 4 or more days before seeking medical attention and, not surprisingly, often presented with lung abscess, necrotizing pneumonia, empyema, or putrid sputum, features that are relatively rare in the current era.

Further supporting the diminishing role of anaerobes in AP, are recent microbiological studies of the respiratory tract in AP revealing the infrequent isolation of anaerobes and, even when isolated, often coexisting with aerobic bacteria. The latter observation is important because, due to the alteration in the redox potential (9,10), treatment of aerobic bacteria alone may lead to less oxygenation consumption and less favorable environment for survival of anaerobes in the respiratory tract.

We should also always consider the potential adverse effects of unnecessary antibiotics with anaerobic activity in our frequently debilitated patients, including gastrointestinal dysbiosis (associated with Clostridiodes difficile infections and overgrowth of antibiotic-resistant pathogens such as vancomycin-resistant enterococci (VRE), hypersensitivity reactions, drug interactions, and central nervous system toxicity (11,12).

Thus, the weight of the evidence does not justify routine anaerobic coverage of AP in today’s patients.


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1. Bartlett JG, Gorbach SL, Finegold SM. The bacteriology of aspiration pneumonia. Am J Med. 1974;56(2):202-7.
2. Bartlett JG, Finegold SM. Anaerobic pleuropulmonary infections. Medicine (Baltimore). 1972;51(6):413-50.
3. Bartlett JG, Gorbach SL. The triple threat of aspiration pneumonia. Chest. 1975;68(4):560-6.
4. Finegold SM. Aspiration pneumonia. Rev Infect Dis. 1991;13 Suppl 9:S737-42.
5. Bartlett JG. How important are anaerobic bacteria in aspiration pneumonia: when should they be treated and what is optimal therapy. Infect Dis Clin North Am. 2013;27(1):149-55.
6. El-Solh AA, Pietrantoni C, Bhat A, Aquilina AT, Okada M, Grover V, et al. Microbiology of severe aspiration pneumonia in institutionalized elderly. Am J Respir Crit Care Med. 2003;167(12):1650-4.
7. Marik PE, Careau P. The role of anaerobes in patients with ventilator-associated pneumonia and aspiration pneumonia: a prospective study. Chest. 1999;115(1):178-83.
8. Bowerman TJ, Zhang J, Waite LM. Antibacterial treatment of aspiration pneumonia in older people: a systematic review. Clin Interv Aging. 2018;13:2201-13.
9. Mandell LA, Niederman MS. Aspiration Pneumonia. N Engl J Med. 2019 Feb 14;380(7):651-663. doi: 10.1056/NEJMra1714562.
10. Walden, W. C., & Hentges, D. J. (1975). Differential effects of oxygen and oxidation-reduction potential on the multiplication of three species of anaerobic intestinal bacteria. Applied microbiology, 30(5), 781–785.
11. Sullivan A, Edlund C, Nord CE. Effect of antimicrobial agents on the ecological balance of human microflora. Lancet Infect Dis. 2001;1(2):101-14.
12. Bhalla A, Pultz NJ, Ray AJ, Hoyen CK, Eckstein EC, Donskey CJ. Antianaerobic antibiotic therapy promotes overgrowth of antibiotic-resistant, gram-negative bacilli and vancomycin-resistant enterococci in the stool of colonized patients. Infect Control Hosp Epidemiol. 2003;24(9):644-9.


Contributed by Amar Vedamurthy, MD, MPH, Mass General Hospital, Boston, MA

Should I routinely select antibiotics with activity against anaerobes in my patients with presumed aspiration pneumonia?