When flu comes home...

This week's New England Journal of Medicine has a study that looks at transmission of H1N1 flu in the household setting. The investigators studied 216 persons with flu (index cases) and their 600 household contacts over a 7-day follow up period. The attack rate for household contacts developing influenza-like illness (ILI) was 10%. The median age of the secondary cases was 14.5 years (median age of all household contacts was 26). Risk of acquiring ILI was age-dependent (compared to adults aged 18-50 years, children 0-4 years had a 3-fold risk, children 5-18 had a 2-fold risk, while the risk for those over 50 years was one-third that of adults under 50 years). The time from onset of symptoms in the index case to onset of symptoms in a secondary case was a median of 2.6 days.

Pomegranates and MRSA

Travelling in Ohio, but had to get in a quick post to suggest what to eat in 2010. Well, not really but perhaps spread on your skin. Researchers in England have found what might be a new class of antibiotic. When mixed with a metal salt, presumably cupric sulfate, and vitamin C, pomegranate rinds have activity against MRSA and other hospital pathogens. You can read the full story in the Guardian here and look at their list of publications here. What I particularly liked is that the story mentioned that there were 20 classes of antibiotics created between 1940 and 1962 but only 3 classes in the 48 years since. I guess if NIH could increase funding for antibiotics beyond the budget dust level, we might have a chance. Hopefully other countries can step in with funding and creative science like this. That is my wish for the new year.

Media and the Public Health Response

Recently, I have become interested in how the media influences the public health response and watched with fascination as the H1N1 saga unfolded. As Mike pointed out earlier, the New York Times has written about the recent transplant-related transmission of Balamuthia mandrillaris and whether this one-off event should change overall transplantation guidelines nationwide. I hope the NY Times' assertion that patients with undiagnosed neurological conditions should be barred from donating organs is analyzed and public health officials don't make a knee-jerk decision based on immediate/transitory media attention or political pressure.

Decisions like these are quite complicated and proper analysis can turn-up unexpected findings. Two years ago, I co-authored an article in the American Journal of Transplantation with Eugene Schweizer and others at the University of Maryland that analyzed what would happen if kidneys were transplanted from donors considered high-risk for HIV or Hepatitis C, yet had tested negative. The current practice is to discard these valuable organs. Our most surprising finding was that the total number of viral infections in recipients was actually LOWER with the policy of transplanting these organs. The reason? It turns out that discarding kidneys from high-risk donors led to more time on hemodialysis which resulted in a higher Hepatitis C incidence in recipients. The transplant policy also resulted in higher quality of life and lower cost of care.

Now, the NY Times article is quite balanced, but this won't necessarily stop public health officials from making decisions before a proper analysis is completed. Let's hope cooler heads prevail before a "national policy on whether to bar people with poorly defined neurological disorders as donors" is decided by officials and not scientists. The one thing that is certain is that there is nothing harder to define than a neurological condition.

More on infections transmitted by donor organs

Over a week ago I noted the two cases of Balamuthia mandrillaris infections transmitted to two organ transplant recipients from a donor in Mississippi. Until today, the media attention had only been local. This morning's New York Times is covering this story and raises the question of whether patients with undiagnosed neurologic conditions, such as the donor in these cases, are acceptable donors or whether they should be excluded from the transplantation process.

Anthrax in the US

The Associated Press is reporting that a New Hampshire woman is in critical condition due to gastrointestinal anthrax. It is believed that transmission occurred via an African drum. Three other cases of anthrax in the US (2 inhalational, 1 cutaneous) have occurred since 2006 associated with goat hides imported from West Africa for djembe drums. Click here to hear djembe drums.

Honesty and fairness in public reporting: Some wishes for the New Year

In the latest issue of Critical Care Medicine there is a study that attempts to determine the role of cross-transmission in the development of nosocomial infections. The two-year study was performed in 11 ICUs in 2 large German hospitals. Surveillance for nosocomial infections was performed and all isolates from cultures which yielded 6 indicator organisms (E. faecium, E. faecalis, K. pneumoniae, P. aeruginosa, Acinetobacter, and S. aureus) were archived for genotyping. Also included were MRSA strains obtained from active surveillance. Over the two years, 1,216 nosocomial infections were identified. Molecular typing revealed that there were 462 episodes of cross transmission (i.e., patients shared the same strain).

What are the implications of this study?
(1) 38% of nosocomial infections had an exogenous source (the infection occurred due to an organism transmitted to the patient in the ICU). One could argue that nearly all of these infections could be prevented by better hand hygiene compliance and perhaps to some degree by reduced contamination of healthcare worker clothing (e.g., a bare below the elbow approach to prevent contamination of sleeves) and decontamination of shared patient care equipment.
(2) 62% of infections had an endogenous source (the infection arose from the patient's own microbial flora). Some of these infections could be eliminated with practices such as central line and ventilator bundles, as well as chlorhexidine bathing. However, there will always be infections in this group which are not preventable (e.g., bloodstream infections of enteric origin in the neutropenic patient). Even if 100% of exogenous and 75% of endogenous infections could be eliminated, that would still leave 15% of all nosocomial infections as non-preventable (i.e., the irreducible minimum).

So in an era of heightened transparency and accountability with public reporting of healthcare associated infections, what needs to be done? Here are my wishes for 2010:
(1) CDC needs to improve surveillance definitions to improve specificity. For example, enterococcal bacteremias in the neutropenic patient should be not classified as line associated infections since these are mostly non-preventable infections with endogenous flora.
(2) States with mandatory public reporting of HAIs need to focus on validation of data submitted by hospitals so that consumers can compare apples to apples. In an informal survey of hospital epidemiologists, I recently learned that some hospitals disregard the CDC central line associated bloodstream infection (CLABSI) definition in the case of enterococcal bacteremia in the neutropenic patient, though a strict interpretation of the CDC definition would not allow this. Were we to do this at my hospital, our CLABSI rates in the medical ICU would fall significantly since enterococci are the predominant bloodstream pathogens in that unit.
(3) CDC also needs to allow hospitals to count each central line present in denominator calculations. Currently, one line day per patient can be counted, even though patients may have more than one line present, each of which is a risk factor for infection. This overestimates the CLABSI rates in my medical and surgical ICUs by 20% and punishes hospitals who care for the sickest patients.
(4) CDC and the professional societies need to educate the public with an honest approach to the concept that most, but not all, healthcare associated infections are avoidable. Stop the APIC-driven "targeting zero" doublespeak (zero infections is not attainable but it's an aspirational goal)! It's confusing to patients, punishes the people who are working hard to prevent infections (ICPs, hospital epidemiologists and front-line providers), and undermines the credibility of ICPs in the medical community.

I still believe that public reporting is the right thing to do. But it sure would be helpful to have a level playing field.

The weekend: It's a good thing!

A new study in BMC Infectious Diseases uses data from eight European countries to model transmission dynamics of an infectious disease spread by close contact in schools. The key finding: the basic reproductive number (the number of secondary cases transmitted by a primary case in a fully susceptible population) falls about 20% on weekends when compared to weekdays.