The world is their Petri dish

The average person harbors at least 10-fold more bacterial than human cells. So I smile whenever I read articles like this one. I guess we're supposed to be shocked, just shocked, to find that densely populated human environments are, well…..not sterile.

Given the range of behavior displayed in public transit systems (245 complaints of urinating and defecating in one year? really??), it makes sense to design the environment with surfaces that are easily cleaned and disinfected. Routine efforts to document microbial contamination in such environments are mostly a waste of time and money. Call me if you’re planning such an effort in your municipal transit system. For half the cost, I’ll predict with uncanny accuracy what you’ll find…..

Don't Let the Patient RIDE THE BUS!!!

If you have a child under 10, you've probably enjoyed Mo Willems classic, Don't Let the Pigeon Drive the Bus!  I've never thought of it as a public health advice book for the Blue's Clues set, but perhaps I should have.

Researchers from Nottingham University wondered if exposure to public transport (bus or tram) within the most recent 5 days was a risk factor for acute respiratory tract infection.  They report in BMC-ID a small case (n=72) - control (n=66) study that riding public transport was associated with a 6-fold increase in presenting to a primary care physician with an acute respiratory infection (adjusted OR=5.94 95% CI 1.33-26.5).  Another interesting result was that it appeared that more frequent riding was associated with a lower risk of respiratory infection: (1-3 uses/week: adjusted OR=0.54, 95% CI: 0.15-1.95; >3 uses/week: adjusted OR=0.37, 95% CI: 0.13-1.06).

Some important caveats: (1) The unadjusted OR for public transportation was only 1.10, 95% CI: 0.55-2.21.  (2) To get to the adjusted OR, they controlled for age, gender, comorbidity, deprivation, child cohabitants, flu vaccination and habitual public transport use.  So, while the findings are intriguing,  negative confounders are extremely rare, so I think this study needs to be repeated.

Now off to read my favorite Mo Willems book: Don't Let the Hospital Epidemiologist Stay Up Late!

Troko J. et al BMC ID, published 1/14/2011