Maryn McKenna

Journalist and Author

News round-up

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I’m deep into writing again and therefore slipping on posting; apologies to regular readers! But here are some items of importance from the past week:

  • Wednesday (Aug. 20) marked the first anniversary of Illinois‘ signing and immediately enacting the MRSA Screening & Reporting Act, the first state law to mandate that hospitals screen all ICU and other high-risk patients for MRSA colonization and to isolate and treat them until they are clear. This law would never have been passed without the extraordinary advocacy of MRSA survivor Jeanine Thomas, founder of the MRSA Survivors Network (site here and in the blogroll).
  • Also as of Wednesday, California came within one step of passing its own MRSA laws, SB 1058 and SB 158. They await the signature of Gov. Arnold Schwarzenegger — but with California’s budget in a $15.2 billion deficit freefall, new legislation there may be held hostage until a budget deal is agreed. Important addition: SB 1058 is also called “Nile’s Law,” after Nile Calvin Moss, who died of MRSA in April 2006. His parents Carole and Ty have pushed relentlessly for a MRSA law in his memory.
  • Plus, a great find thanks to Carole Moss: The Washington State Department of Health has put together an excellent pamphlet, Living with MRSA, that explains MRSA infection, colonization, decolonization and infection-control care at home in excellent everyday language.
  • And finally, another blog worth knowing about: GERMblog, written by Dr. Harley Rotbart, professor and vice-chair of pediatrics at University of Colorado School of Medicine and author of Germ Proof Your Kids: The Complete Guide to Protecting (Without Overprotecting) Your Family from Infections. I interviewed Dr. Rotbart recently for a magazine story and his advice was clear, science-based and sensible. His blog is now in the blogroll.

Antibiotic resistance in food animals all across Europe

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Via a journal that’s new to me — the Acta Veterinaria Scandinavica, the open-access journal of the Veterinary Associations of the Nordic Countries — comes an amazing review of the prevalence of antibiotic resistance in cattle in 13 European countries. Based on 25,241 isolates collected over three years, Denmark, Britain, the Netherlands, Norway, Sweden and Switzerland do well, but “many isolates from Belgium, France, Italy, Latvia and Spain were resistant to most antimicrobials tested.“

Most resistant pathogen: E. coli. MRSA is present as well:

Of major concern is the level of resistance to oxacillin and 3rd generation cephalosporins (i.e. ceftiofur) in S. aureus. The prevalence of oxacillin resistance in Spain (3.7%) and France (8.3%) and the resistance towards cephalosporins in Spain (0.9% in 2004) and France (4.2% in 2002; 1% in 2003) indicate the presence of methicillin resistant S. aureus (MRSA) in these two countries.

The authors ascribe the differences among countries to different patterns of antimicrobial use by veterinarians and stress that it is time for veterinarians to begin using measurements of local resistance patterns (in human medicine, an “antibiogram”) before prescribing. Cite coming when the Acta site is updated. UPDATE: The paper is here; cite is: Hendriksen, RS et al. Prevalence of antimicrobial resistance among bacterial pathogens isolated from cattle in different European countries: 2002-2004. Acta Veterinaria Scandinavica 2008, 50:28doi:10.1186/1751-0147-50-28.

I wasn’t aware that this same set of authors (Hendriksen, RS et al.) just a few weeks ago published a similar review of antimicrobial resistance in pigs in Europe. It looks at several bacterial species in pigs, but unfortunately for our purposes, no S. aureus.

MRSA colonization – the long-term risk

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One of the ongoing puzzles of MRSA’s behavior is the significance of colonization, that situation of MRSA living on the skin — or in the nostrils or other locations close to the body’s external surface — without causing illness. It’s not known how frequently MRSA colonization occurs, for one thing: The long-standing estimate of 1% of the population has been challenged by a number of recent studies.

Another persistent question has been whether the risk of illness and death changes as colonization continues. It has been established that up to one-third of newly colonized carriers will become seriously ill within a year of their acquiring the bug (Huang, SS. et al., Society for Healthcare Epidemiology of America Annual Meeting 2006, abstract 157 – not online that I can find)— but what happens beyond that? Does the risk of illness persist or decrease?

In Clinical Infectious Diseases, the same team that defined the risks of recent colonization report that there are significant risks to long-term carriage as well: 27% of invasive illness in the second year and 16% thereafter, based on a review of 281 patients who were followed for at least one and up to four years at Brigham & Women’s Hospital, a Harvard Medical School teaching hospital. These patients become very ill, and in addition use a significant amount of health-care resources:

At our hospital, there are 2–3 times as many hospital admissions involving patients previously known to harbor MRSA than there are hospital admissions of individuals who are newly detected as MRSA carriers each year.

What is the precipitating event that tips MRSA carriage over into MRSA illness? It may be health care. In other words, the long-term carriers do not become ill with MRSA disease and then come to the hospital. Instead, they come to the hospital for some other reason, and the surgery, IV placement, dialysis etc. they receive allows their MRSA strain to slip past the protective barrier of their skin and begin an invasive infection.

We submit that these high risks of MRSA infection among culture-positive prevalent carriers are not only preferentially detected because of hospitalization but may, in fact, be incurred because of the device-related, wound-related, and immunologic declines associated with a current illness.

This raises the question of whether any admitted patient found to be colonized should undergo the routine known as decolonization before any other procedures are performed — and whether institutions and insurance companies will be open to the additional hospital days and drug costs that will represent.

The cite is: Datta, R. and Huang, SS. Risk of Infection and Death due to Methicillin-Resistant Staphylococcus aureus in Long-Term Carriers. Clinical Infectious Diseases. 2008 47:176-81.

The “vicious cycle” of HA-MRSA

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In the new issue of Lancet Infectious Diseases there’s a marvelous analytical review of the complex relationship between hospital overcrowding and understaffing and the rise of hospital-acquired MRSA.

You can feel intuitively that these phenomena must be linked:

  • If a hospital has more patients, its staff will be more stressed;
  • If they are more stressed, they may neglect handwashing and other infection-control measures;
  • If budget shortfalls cause staff cuts, the remaining staff will be more stressed still;
  • If infection control is neglected, more patients will acquire MRSA;
  • Since MRSA patients are sicker and stay longer, more beds will be full;
  • Since there are more patients, staff will be more stressed;
  • Since MRSA patients are more costly, budgets will be more stressed.

And so on. Because it is a review article it is also an excellent guide to the medical literature on this aspect of the MRSA problem, with 140 cites.

The citation is: Clements, A. et al. Overcrowding and understaffing in modern health-care systems: key determinants in meticillin-resistant Staphylococcus aureus transmission. The Lancet Infectious Diseases 2008; 8:427-434.