Superbugs vulnerable to virus?

Bacterial infections, including so-called superbugs, or antibiotic-resistant bacteria, may ultimately be addressed by viruses, or at least that’s the hope indicated by a study recently published in the journal Nature.  It may sound like the plot of a cartoon or video game, but researchers at Tufts University School of Medicine found the first evidence that bacteriophages can “hijack” the host bacteria’s immune system and use it to destroy that host. Bacteriophages (or phages, for short) are viruses that prey on specific bacteria. The study followed a phage that is a viral predator of Vibrio cholera, the bacterium that causes human cholera epidemics, and verified the results by infecting the same strain of cholera bacteria with phage that lacked the adaptive immune system.

Most bacteria are vulnerable to phages, and have immune mechanisms to protect themselves. About half of known bacteria use an adaptive system, CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats) that can rapidly respond to a wide variety of attacks. Phages were previously believed to be primitive DNA or RNA particles. This is the first evidence that something as complex as an adaptive immune system can be transferred from a bacteria to a virus. Once it’s transferred, that immune system adapts and turns on its former owner, and then the virus can replicate and destroy more bacteria.

With this knowledge, phage therapy, using phages to treat bacterial diseases, moves a little closer to becoming a reality. The research team is currently studying the mechanism by which the phage immune system disables the cholera bacteria’s defenses, a step towards the design of a phage therapy for cholera in humans. Hopefully, phage therapy for other superbugs will follow.

Holding out such hope is especially important in light of the recent report from the Centers for Disease Control and Prevention about the rise of carbapenem-resistant Enterobacteriaceae (CRE). Those CRE germs are resistant to nearly all current antibiotics, and what’s worse, are able to spread that resistance to other bacteria.

Until phages or other solutions are available, a multifaceted approach to getting superbugs under control is essential. We have to focus on reducing the risk of infection in addition to detecting and treating existing infections. Superior environmental hygiene practices are a critical part of that process, but are often dependent upon the vagaries of human behavior. While proper hand hygiene is the keystone of effective infection prevention systems, compliance is always lacking. So, healthcare leaders need to adopt technologies that continuously reduce bioburden on hospital surfaces around the clock – independent of human intervention.

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Bacteriophage  (virus that infects bacteria)

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Hand Hygiene in Everyday Life

Hand Hygiene in Everyday LifeWe wouldn’t normally look to a study about business sustainability for data about handwashing and hygiene, but the 2012 Tork Report:  The Sustainability Gap  contains an informative, and sometimes troubling, section on the effects of health and hygiene on sustainability.

For example, although 70 percent of Americans say they practice good hand hygiene,

  • 33 percent of men don’t wash their hands after using the restroom. (Time to rethink that hearty handshake?)
  • 98 percent of those interviewed underestimated the average number of surfaces we touch every 30 minutes (answer: 300)
  • Only 10% of Americans knew that germs stay alive for 48 hours on inanimate surfaces.
  • Fewer than half of Americans wash their hands after using exercise equipment, handling money, or taking public transportation, each of which is likely to be more contaminated with germs than the restroom.
  • 47 percent of employed adults in the U.S. eat meals at their workstation, where desks can carry 400 times more dangerous bacteria than the average public toilet seat.

So while we’re all in the mode of resolving to change some behavior or other, we can try to wash our hands more frequently, and eat at our desks less often. And, it’s probably a good time (any time is probably a good time) to use a disinfectant wipe on your workstation.

Healthcare Associated Infections in Perspective

To get a sense of the overall scope of the HAI problem, it may help to look at some of the measurable goals and the progress towards those goals. As we consider the size and impact of healthcare associated infections (HAIs) in the only ways those factors can actually be measured, we want to acknowledge that the medical, financial, and emotional cost of HAIs to individuals and families is incalculable.

A quick look at the metrics explain why the effort to prevent HAIs is so compelling on economic as well as moral grounds:

  • 5% (1 in 20) of all hospitalizations in the U.S. result in HAIs 1
  • 1.7 million HAIs result in 100,000 deaths in the U.S. every year
  • Annual U.S. direct medical costs due to HAIs is in excess of $28 billion1
  • 8.7% (~1 in 12) of all hospitalizations worldwide result in HAIs2
  • 30% of intensive care (ICU) patients in high-income countries are affected by HAIs. Low- to middle- income countries could easily see double that rate.2

In other words, in the U.S. HAIs cause more deaths than AIDS3, breast cancer4, and auto accidents5 combined. The extra direct medical costs in the U.S. could pay for about half of the government’s spending for Medicare Part D6 (prescriptions).

It’s worth noting that dollar costs are generally stated as direct medical costs including treatment and resource costs of extended hospital stays due to HAIs. Some economists7 would argue, though, that including the opportunity costs of those resources—the value of their alternative uses—yields a more accurate assessment. The opportunity cost argument would increase the economic burden from HAIs, and would thus justify higher expenditures to prevent infections.

Progress

HAIs are indeed a huge and complex problem, and many groups and government agencies are working on solutions. The U.S. Department of Health and Human Services is shepherding an effort to prevent and ultimately eliminate HAIs. Created in 2009, The National Action Plan to Prevent Healthcare-Associated Infections: Roadmap to Elimination contains five-year targets for reduction of infections or hospitalizations in several areas, and the update reports progress as of October 2011.

A few areas are on track to meet 2013 targets:

  • Central-line associated bloodstream infections should be reduced by 50%
  • Catheter-associated urinary tract infections should be reduced by 25%
  • Surgical site infections should be reduced by 25%
  • MRSA bacteremia data is not yet available, but rates have shown progress towards the 25% reduction goal

But one key area has shown less progress toward the reduction goal:

  • Clostridium difficile infections have leveled off, but not decreased, so a 30% decrease by 2013 seems unlikely.

A quick look at that plan’s executive summary confirms the HAI problem’s complexity and the resulting need for a multifaceted approach:

  • Hand hygiene
  • Equipment sterilization
  • Isolation
  • Environmental service protocols
  • Staff and consumer education
  • Surface sanitation
  • Antimicrobial surfaces

All of the above are important elements of the solution. Hand hygiene is essential, but alone it’s not sufficient to the task of preventing HAIs.

Steady progress towards reduction goals in most of the measures is encouraging. However, such progress is rarely linear or easy to predict: the most easily achieved results come early in the process, and the rest is often slower to realize. Even if and when HAIs are eliminated, constant vigilance and renewed effort will be required to avoid recurrence or new infections from new sources.

 

1 U.S. Centers for Disease Control and Prevention

2 World Health Organization

3 Centers for Disease Control and Prevention, (CDC) (2011 Jun 3). “HIV surveillance–United States, 1981-2008.”. MMWR. Morbidity and mortality weekly report 60 (21): 689-93. PMID 21637182

4 American Cancer Society. Cancer Facts & Figures 2012. Atlanta: American Cancer Society; 2012.

5 ^ “FARS 2010″. National Highway Transportation Safety Administration.

6 Health Care Spending and the Medicare Program – A Data Book – June 2012 Medicare Payment Advisory Commission

7 Graves N. Economics of preventing hospital infection. Emerg Infect Dis [serial online] 2004 Apr [date cited]. Available from: http://wwwnc.cdc.gov/eid/article /10/4/02-0754.htm

Scrubs and Uniforms: Are Garments Spreading Infections?

Several studies have found that scrubs, uniforms, even healthcare workers’ ties can harbor harmful bacteria. While studies have yet to conclusively prove the role of such garments in actually spreading infection, common sense about the likelihood has led many healthcare facilities to institute relevant precautions. Those precautions include things like encouraging healthcare workers to change to civilian clothes before leaving the facility and providing either in-house or contracted third-party laundering of scrubs and uniforms.

If scrubs are carrying harmful bacteria, then at least the perception, if not the reality, that uniforms are spreading infection would make it inadvisable to wear scrubs outside the facility, especially in sandwich shops and produce markets. Even with the best staff intentions, home laundering water temperatures are sometimes inadequate to eliminate resistant bacteria. The heat of ironing would help, but compliance with simply washing uniforms is uneven at best.

A quick review of a few studies explains why some institutions are taking the conservative approach despite the absence of conclusive evidence:

  • One study found that bioburden found on scrubs laundered at home prior to use was greater than those laundered at the healthcare facility or a third-party healthcare laundry after the latter had been worn for a day in the operating room.
  • Another study found potentially dangerous bacteria on more than 50 percent of doctors’ and nurses’ uniforms tested.
  • Half of the ties worn by doctors and medical students were found to harbor several pathogens, compared to only 10 percent of the ties of security guards at the same facility.