Drug-resistant bacteria in bedbugs

Being Scary Disease Girl, I seem to have earned a reputation for never wincing in the face of weird disease threats.

But this, I admit, makes me go squick:

Researchers in Vancouver, BC have found bedbugs there carrying drug-resistant staph, MRSA, and vancomycin-resistant enterococci, VRE.

(Deep breath.)

(Another deep breath.)

OK, details:

In the June issue of the CDC journal Emerging Infectious Diseases, Christopher F. Lowe of the University of Toronto and Marc G. Romney of the University of British Columbia relay an observation they have made about bedbugs being carried by three patients who live on Vancouver’s Downtown Eastside — a neighborhood they describe as “an impoverished community in Vancouver with high rates of homelessness, poverty, HIV/AIDS, and injection drug use.”

(NB: The CDC provided a .pdf of this paper to the media ahead-of-print without giving an exact URL. I’m writing this early because I’m not in my usual time zone but still want you all to know about it as soon as possible, and setting it to publish when the embargo lifts. When it goes live, the paper will be on this page. I’ll update with a direct link as soon as I can. Here’s the link.)

All three patients were hospitalized (Romney is affiliated with St. Paul’s Hospital in Vancouver, which cares for patients from Downtown Eastside) and found to be infested with bedbugs. Homelessness, poor hygiene and crowded living are causes of some disease conditions and coincidentally linked to others, so the researchers got the idea to check the bedbugs for any disease-causing organisms.

Bugs that came from two of the men were carrying VRE, a gut bacterium that has become a very serious problem in hospitals in the past decade because it is resistant to vancomycin, one of the drugs of last resort for overwhelming infections. The isolates in the bugs from the two men were also resistant to three other drug classes. Bedbugs from the third man were carrying the classic community-associated strain of MRSA, resistant to beta-lactam antibiotics (semi-synthetic penicillins, cephalosporins) and erythromycin.

So: That’s icky. Is it significant?

The authors point out that several research groups have tried in the past to link bedbugs and disease transmission (of hepatitis, for instance) and have failed. They certainly have not proven transmission in this case. But they also say that there is a density of these two organisms in the area where the men live that make it more likely that bedbugs could be involved in diseases pingponging through the neighborhood. First, there’s the high density of bedbug presence, in 31 percent of Downtown Eastside residents. Second, there’s the high prevalence of MRSA, in 58 percent of the skin infections in the St. Paul’s ER. And third, there’s the previously recorded and persistent presence of VRE in in-patients at St. Paul’s.

The US CDC believes that crowding, poor hygiene and skin disruption increase the likelihood of MRSA infection; crowding and poor hygiene are common in homelessness and shelter living, and bedbugs by definition disrupt the skin’s barrier by their bites. Meanwhile, in the ill and hospitalized, VRE frequently causes infections in disrupted skin, such as a surgical incision or a diabetic ulcer.

The authors say:

…These insects may act as a hidden environmental reservoir for MRSA and may promote the spread of MRSA in impoverished and overcrowded communities. Bedbugs carrying MRSA and/or VRE may have the potential to act as vectors for transmission.

To be clear: The victims here are also the ones who are likely to be most at risk. What this paper says, first of all, is that the substandard living conditions of being poor and homeless make those who are poor and homeless more likely to be vulnerable to yet more dangerous and difficult diseases. As with so many other health disparities in North American society, this is a social justice issue.

But if I am candid, it is also a reminder to the more-privileged rest of us that bedbugs have spread explosively, in a manner that is not completely understood, and that they pose a disease-transmission risk that is not yet well-defined.

And therefore, if you’ll excuse me, I’m going to go check my hotel mattress. Just in case.

Update: Twitter follower @KateWong points out that last fall, Crain’s New York speculated about drug-resistant infections being transmitted by bedbugs in hospitals. I say again: Squick.

Cite: Lowe CF and Romney MG. Bedbugs as Vectors for Drug-Resistant Bacteria. Emerg Inf Dis. June 2010. Ahead of print.

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