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Infection control measures prove difficult to study

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November 28, 2018

Researchers systematically reviewed and reanalyzed past studies on the prevention and control of carbapenem-resistant Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa in health care facilities and found them difficult to compare and filled with low-quality data.

Nevertheless, the findings provided the basis for international recommendations made by WHO last year for the prevention and control of these carbapenem-resistant organisms.

Writing in Clinical Infectious Diseases, Sara Tomczyk, epidemiologist with WHO, and colleagues noted the importance of effective and targeted infection prevention and control interventions where carbapenem-resistant Enterobacteriaceae (CRE), A. baumannii (CRAB) and P. aeruginosa (CRPsA) are endemic or causing an outbreak.

“CRE-CRAB-CRPsA have been highlighted as critical pathogens in the WHO prioritization of pathogens to guide discovery, research and development of new antibiotics for drug-resistant bacterial infections,” they wrote. “To provide the evidence for global guideline recommendations, we conducted a systematic review to assess the impact of practices and procedures to prevent and control CRE-CRAB-CRPsA transmission in health care facilities both in endemic and epidemic settings.”

Tomczyk and colleagues searched six databases for studies published up to January 2017 and abstracts from five international scientific conferences between 2012 and 2016. They sorted studies for bias based on effective practice and organization of care (EPOC) quality criteria and, when possible, reanalyzed before-and-after studies as interrupted time series studies.

According to the review, 76 studies were identified, including 22% (n = 17) that were EPOC-compatible, all of them interrupted time series studies with durations between 15.6 months and 7 years. Of the 17, 65% (n = 11) assessed CRE, 29% (n = 5) assessed CRAB and 18% (n = 3) assessed CRPsA.

According to Tomczyk and colleagues, almost all infection prevention and control measures included multimodal strategies using three or more components. Specifically, these approaches were used in 91% (n = 10) of studies assessing CRE, 80% (n = 4) assessing CRAB and 100% (n = 3) assessing CRPsA. Significant reduction in postintervention outcomes were reported for 90% (n = 9) of CRE studies, 75% (n = 3) of CRAB studies and 67% of CRPsA studies (n = 2).

At 90%, contact precautions were the most frequently implemented intervention among all CRE-CRAB-CRPsA EPOC studies, Tomcczyk and colleagues reported, followed by active surveillance cultures and monitoring, audit and feedback (both 80%), patient isolation or cohorting (70%), hand hygiene (50%) and environmental cleaning (40%). A significant reduction in slope and/or level was observed in nearly all the studies with these intervention components, Tomczyk and colleagues said.

“In contrast to previous reviews, the current article provides a methodologically focused, rigorous systematic review with a reanalysis of quasi-experimental studies to assess the impact of practices and procedures to prevent and control CRE-CRAB-CRPsA transmission in health care facilities,” they wrote.

In an accompanying editorial, Susan C. Bleasdale, MD, medical director of infection prevention and control at the University of Illinois Hospital & Health Sciences System and associate professor of clinical medicine in the division of infectious diseases at the University of Illinois College of Medicine in Chicago, noted the importance of stewardship and infection prevention in controlling clinically significant multidrug-resistant disease, but said it is difficult to measure their impact on individual encounters and to determine the impact of an individual intervention within a bundle. She called the review “very thorough” but said the evidence provided was of low quality, underscoring the “limitations of evidence-based guidance” for infection prevention and control.

“A more focused meta-analysis of studies with similar characteristics might provide more evidence-based guidance but might not be necessary. Instead of reanalyzing prior work and interventions, perhaps we just need to get better at these basic [infection prevention and control] elements and focus research efforts and investments on developing the next novel intervention to prevent [health care-acquired infections],” she wrote. – by Marley Ghizzone

Disclosures: Bleasdale and Tomczyk reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.

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