- Genetic fingerprinting analysis reveals information about the outbreak
- The results show the microbe spread despite containment efforts
- Similar outbreaks are happening nationwide, one writer says
- The overuse of antibiotics paves the way for drug-resistant microbes
Reports of "superbugs" that can evade our strongest antibiotic treatments are becoming uncomfortably commonplace (think MRSA), but that's no reason to become complacent about the growing threat from invisible armies of microbes.
We got a reminder of that during one such outbreak of the latest microbial villain, carbapenem-resistant Klebsiella pneumoniae, or CRKP, that occurred at one of the nation's premier hospitals, the Clinical Center of the National Institutes on Health, last year.
Although the incident is a year old, researchers just reported on a state-of-the-art genetic fingerprinting analysis of the gut bacterium to reveal that despite the best containment efforts, the wily microbe managed to break free of protective barriers meant to keep it in check and spread to 17 patients, killing six (five others died of other conditions, but their health was likely worsened by infection with CRKP).
So what lessons can we learn from the outbreak?
The genetic sequencing of the bacterium shows that the infection originated with what scientists call an index patient, in this case a 43-year-old woman who had come to NIH from a New York hospital already infected with CRKP.
Every possible measure to prevent the spread of the germs was used. She was kept in isolation in intensive care, staff who cared for her wore masks, gowns and gloves every time they interacted with her, dedicated equipment was set aside exclusively for her use and every item used in her treatment was immediately sterilized or disposed of as infectious waste.
When she was moved to a private room, she wasn't even allowed to walk in the hallway unless it was empty and she was wearing a gown and gloves. She left the hospital after a month; her room was cleaned twice and doctors believed that they'd successfully kept everyone else safe.
But, as the genetic sequencing ultimately discovered, the bug lurked in sink drains and in a respirator that had been sterilized, although the process had apparently failed.
Each week for several months after the patient was discharged, other patients became sick with the bacterial infection. The hospital ultimately had to tear out its plumbing and rectally swab all of its patients to make sure the bug hadn't somehow gotten into their systems in order to end the outbreak.
The high-tech sequencing is a critical tool for tracking drug-resistant microbes like CRKP, and it could give doctors a head start on stopping spread of such potentially deadly infections in their tracks.
But for now, most hospitals aren't equipped to generate such data. And, as Maryn McKenna, a journalist who wrote a book on disease-resistant germs notes in her blog on Wired:
"There was nothing unusual about this outbreak, other than the resources that the NIH infection preventionists were able to marshal to attack it by means of their unique funding. Outbreaks of CRKP and other (similar diseases) are happening in health care across the United States -- at NIH, at academic medical centers, at community hospitals, in nursing homes -- all the time.
"That is not to say that the occurrence of CRKP is not an emergency. It is," McKenna wrote. "The point is that it is an emergency happening, not just in a single hospital, but across the entire country, and that we are completely failing to address."
McKenna explains that this bacteria is treatable with only two drugs: one that is known to cause kidney damage and another that can't get into all of the organs that can be infected. If it develops resistance to them, it will be completely untreatable -- and no new drugs for it are currently in development.
Since CRKP was first spotted in 1996, the germ and related resistant bacteria are known to have spread to 39 states and over a dozen countries.
While hospitals are making laudable attempts to fight these outbreaks, they are typically not specifically reimbursed for infection control efforts and little money is spent on developing better infection prevention techniques.
And at the same time, we're providing fertile ground for the emergence of more drug-resistant microbes by overusing antibiotics, not just in health care settings by medicating every sore throat or sinus infection, but on farms across the country as well, where animals such as chickens and cattle are loaded up with antibiotics not just to try to prevent infections, but to spur growth.
This practically ensures that the fortunate bacteria that are somehow able to survive exposure to these drugs will flourish, and out-populate those strains that can't. It also ensures that any bugs that do grow resistant will be able to spread easily.
Eighty percent of all antibiotics are used this way; a stunning 29 million pounds of the stuff is fed to livestock each year.
It's not that we should ever expect to completely contain infections or hope to stamp out the rise of superbugs -- given the remarkable ability of microbes to survive and evolve over millennia, that's unrealistic.
But we can become smarter about protecting ourselves from outbreaks like the one that occurred at NIH; first, by using each encounter as a learning opportunity to improve our containment and prevention strategies and by improving systems to respond, and second, by remembering that each outbreak is a sobering reminder that when it comes to disease-causing bugs, we're still playing catch-up.