10 March 2009

Resistant bacteria on health care workers' phones

Here's some of the news that I mentioned Friday - no, I'm not hoarding, I'm just desperately behind on some writing (and falling further down the curve all the time, but thanks for the concern).

A team from Ondokuz Mayis University in Turkey, publishing in the open-access journal Annals of Clinical Microbiology and Antimicrobials, looked beyond the concern over health care workers' hands being clean, and decided to interrogate what those workers hold in their possibly-not-clean hands. They swabbed and tested the hands of 200 health care workers ("15 senior, 79 assistant doctors, 38 nurses and 68 healthcare staff "), and 200 phones. Their results:
  • 94.5% of phones colonized with bacteria
  • 49% of the phones grew one bacteria
  • 34% grew two species, 11.5% three or more
The language in the paper is a bit difficult, but if I'm reading it right, the colonization rates look like this:
  • 50 of the phone and 53 health care workes carried S. aureus (approximately 25%)
  • 52% of the S. aureus strains on phones were MRSA
  • 37.7% of the S. aureus strains on hands were MRSA.
Other organisms on the phones and the hands were other staph species, coliform, enterococci, moulds and yeasts.

The health care workers were certainly not infection-control outlaws: They washed their hands regularly. But only 10% of them had ever thought to clean their phones — which are held by the mouth and nose, a prime site for staph colonization, and go with them everywhere in the hospital, including to the OR and the ICU. (The paper doesn't make clear whether the phones in question are hospital-supplied, with potentially many users, or personal, with one user, but going from hospital to home and back again.)

So: We've talked in the past about the many challenges of infection control in hospitals — all the many, tiny details in multi-person, highly technological health care that can trip up even well-intended infection control. (Remember the sinks?) Here's just one more example of the unfathomable complexity of the journey of attempting to get to zero in healthcare-associated infections — a place, of course, where we all want to be.

The cite is: Ulger, F., Esen, S., Dilek, A. et al. Are we aware how contaminated our mobile phones are with nosocomial pathogens? Annals of Clinical Microbiology and Antimicrobials 2009, 8:7doi:10.1186/1476-0711-8-7


Lisa said...

After reading your article, I recently came across a new product called Wireless Wipes.
This new product cleans and disinfects our cell phones, leaving a green tea cucumber scent.

daedalus2u said...

A problem with wipes is that there is porosity that the wipes can't get to. I think a better technique might be to make the porous parts of the phones UV transparent and make the whole phone UV resistant. Then whole phones could be UV sterilized periodically. At least every day when entering and leaving the hospital. This could even be faster than any wipe-down procedure. It is the integrated UV dose that is microbicidal. The time that dose is given in doesn't matter.

I don't think that incorporation of antimicrobial agents into the plastic that phones are made of is a good idea. At some point the levels will drop below where bacteria are killed, and that will then foster resistance to that agent. Worse, many antimicrobial agents (such as pine oil) foster broad spectrum resistance by upregulating antibiotic export pathways.

Maryn McKenna said...

That's a really interesting idea, Daedalus. I remember that one of the ERs I observed in during a fellowship a few years ago had Nextel phones that were handed off to a few key staff members at the start of every shift, and periodically plugged back in to charging stations. I could easily imagine a charging station with a UV light integrated into it. (Hmmm... business idea? 'Scuse me, must go Google the Patent Office...)

daedalus2u said...

The tricky part is to make the phone out of plastic that is transparent to UV and yet resistant to it. Only the parts that are porous need to be, where the speaker is. Without holes for a speaker/microphone the problem becomes a lot simpler. Most plastics are only resistant to UV because they are made opaque using carbon black or because they contain compounds that effectively act as sun-block. There are relatively few plastics that are transparent and resistant, things like PTFE are, but then tend to make lousy plastic components. They would have to be specially made, with the internal components that are not UV resistant shielded from the UV yet not capable of being a site where bacteria could reside. That is not difficult to do. There are many potting compounds that could be used. The resulting phones might not be sufficiently aesthetic for mass appeal.

I don't think that combining a charger with a UV sterilizer would be the best idea. A UV sterilizer can be made to work very fast; a few seconds at a very high UV flux would work and be completely effective. That level of UV would also cause intense sun burn in those few seconds. It would also cause ozone in air (which is not a problem in a sealed unit, the air could be exhausted through a catalyst that destroys it). The sterilizer would cost a lot more than a charger but could be used by many phones during the time it would take to charge a single phone.

You could have a station where people put their phones through it as they enter and leave the hospital. On a conveyer belt the throughput could be very high. If people sanitized their hands with alcohol while they were waiting, the phone wouldn't be recontaminated.

You could have something that looks like a microwave. You put it in, close the door, give it a zap, and take it out. You could have a window transparent to visible light so you could watch the process.

KoKo said...

I was wondering, about coffee shops that are close to hospitals... I routinely see hospital workers, nurses, doctors in scrubs and lab coats... ordering there. I would love to swab and plate samples from there!