Evidence-based infection prevention: A modest proposal

This is a special guest post by David Hartley, PhD who is a Research Associate Professor in the department of Microbiology and Immunology at the Georgetown University Medical Center.

I don't know if there are dedicated courses in schools of medicine and nursing in the US devoted specifically to hospital infection control and prevention, but if there are, I haven't found them. There are lots of training courses offered by trade societies, and many of these are great at conveying procedure, technique, and rationale, but I'm thinking about academic, didactic courses presenting a comprehensive picture of what is known, how it is known, and emerging ideas about infection control and prevention. Any science-based course should expose the learner to the continuum of theory, evidence, and practice. I think it could be done in a semester.

How best to approach such a course needs to be discussed and worked out, but one might, for example, begin with a survey of what we know about what people are commonly colonized and infected with, and how they got that way. This would entail examination of aerosol, alimentary, percutaneous, and other infectious pathways as appropriate, focusing upon important pathogens of concern in healthcare facilities. It could then go on to examine microbial life histories along each route of infection, and how common hospital practices act synergistically or antagonistically with each such route. Host response to infection would be important to cover, and a quantitative epidemiological component should also be included. To tie everything together, learners could undertake a final project assessing what current infection prevention practices are evidence-based and which aren't, and what evidence might be useful for better informing infection control practice. Such a course might be entitled Infection Control and Prevention: From Science to Practice. If done well, the course could help to train learners to think about infection within the context of a coherent, interconnected, evidence-based picture.

By and large, it seems like such an expansive, theoretical picture of hospital infection control and prevention is lacking at present. There are mathematical and computer models of varying complexity and realism that together have led to insights, though how to generalize and apply these is sometimes unclear to preventionists. There are also rules and guidelines, though some (many?) are not as well studied as one might expect (e.g., handwashing and contact precautions). There are increasing numbers of studies suggesting that this intervention works here and that intervention works there, but understanding how all this knowledge fits together to inform thinking and practice, in a truly robust way, remains elusive. A systems approach to both teaching and thinking about infection prevention may prepare the next generation of researchers and clinicians to think more holistically and progressively about infection in healthcare environments.


  1. Great post. Perhaps Infection Control and Prevention: From Science to Practice could be developed in a MOOC format and then implemented in a "hybrid course"-- MOOC lectures + in-person discussion sections at medical schools and nursing schools.

    1. Modern modalities of delivery certainly have their place in training, and a MOOC might be a useful way to disseminate such material. I like the idea of a hybrid course, thanks for suggesting it.

  2. David Hartley raises important issues in his commentary. I would like to add my perspective as someone who has taught at medical schools in three different settings, including my native Germany and two English-speaking countries. In Germany, there is an academic subject called "Hygiene" that is usually taught for one full semester (half a year) as a firm component of medical courses at medical schools. The term Hygiene in this context will seem unusual to most English speakers, but in the German context, this subject is a conglomerate out of hospital infection control, public health and aspects of environmental toxicology (for example, one also learns about how public water supplies are made safe for drinking). The founding father of this subject is Max von Pettenkofer:
    I was taught in Hygiene while attending medical school in the 1980s, and then myself taught it to medical students through the 1990s while working at a Department of Hygiene and Medical Microbiology. The teaching, course arrangements and how it was taught left much to be desired, but at least this constituted an approach to structured teaching as a firm part of medical school education for one full semester. Fast-forward to the 2000s, to my teaching appointment in the first of the two mentioned English-speaking countries, and the medical school curriculum contained only two (I repeat, two) one-hour sessions of teaching dedicated to anything infection control-related during the entire medical course before students graduated as doctors. After hard lobbying to medical school officials, I managed to increase this to a "whopping" four sessions dedicated to infection control. The arrangements at medical schools in the setting where I moved subsequently are better, but still leave a lot to be desired. Also, there seems to be an attitude difference in teaching. In the latter two settings, there seems to be an (unspoken) sense that you immerse students in clinical bedside rotations, tell them to "adhere to proper practices" and watch them absorb good infection control practices in an osmosis-like fashion. In the first setting, there is an emphasis on making students understand WHY certain measures are necessary, on a theoretical basis.
    I would also like to caution a little against overusing nice-sounding terms like "evidence-based" and "systems approach". Over the years, I have come to the personal conclusion that the pure evidence-based approach as I often see it advocated is somewhat too narrow to give the full picture. In my opinion, the teaching of evidence from clinical studies and clinical observations should always be complemented by trying to understand and teach the theoretical and conceptual underpinnings. Like the knowledge of physiology, pathophysiology, and "how things work". This may be explained with one very simple example that, however, is not usually well understood by students unless the theoretical underpinnings are also explained. This is the contact time of a skin antiseptic on skin before a procedure (puncture, surgical incision, etc.) can be started. The pure evidence-based approach has very little information power in this regard. Now come in from a microbiological angle and explain classical time-kill curves and that these behave similarly to radioactive decay curves (which most high school students will have learnt in physics), and you create an "Aha!" effect. I certainly had this when I was taught this as a medical student.

    1. Your experience is helpful and revealing, thank you for sharing. Regarding use of the terms "evidence based" and "systems approach", I agree completely that the terms are overused. By "evidence based" I meant to inject the notion that, as Cabana and Wachter (2011) have recently put it, "Goethe wrote, 'Knowing is not enough; we must apply.' However . . . before we apply, we must be sure about what we truly know." What constitutes the act of "knowing" varies from field to field. Infection prevention is the confluence of several fields, including, e.g., microbiology, epidemiology, medicine, and environmental engineering. There are varying levels of certainty within every field, ranging from lore to intuition, observation, and measurement. All are valid in different circumstances, but I believe it's desirable to move towards the measurement end of the spectrum if we are to understand infection in a comprehensive and ultimately effective way. By "systems approach", I meant the process of relating knowledge in one area to knowledge in other areas -- because, exactly as you point out, learners understand better when the theoretical underpinnings of what is presented are made clear. Relevant theoretical underpinnings for infection prevention can be drawn from many fields. The connections are key.

      Your comment on the assumption of osmosis-like absorption is striking and important; thus the importance of instruction in this area. Similar circumstances have been noted in other fields, as has been pointed out by Richard Feynman (1974; http://neurotheory.columbia.edu/~ken/cargo_cult.html) in the case of physics instruction. He conveyed the notion directly in the following way: "But this long history of learning how to not fool ourselves . . . is, I'm sorry to say, something that we haven't specifically included in any particular course that I know of. We just hope you've caught on by osmosis. The first principle is that you must not fool yourself -- and you are the easiest person to fool. . . . After you've not fooled yourself, it's easy not to fool other scientists." The issue of how best to train people on things that are crucial isn't necessarily easy or obvious. Maybe education in the area of infection prevention can be improved with some of these ideas or extensions or evolution of them.

      Cabana, M. D. and Wachter, R. M. (2011). The hazards of drawing conclusions from before-and-after studies of system-level interventions: knowing may not be enough. Arch Pediatr Adolesc Med, 165(5):472-473.


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