MRSA Towels

The CDC posted a report about suspected and culture confirmed cases of Methicillin resistant Staphalycoccus aureus (MRSA) showing up in late 2007 among football players in Brooklyn.  MRSA was found on the skin of 6 of 59 of the football players, and the CDC suspects that sharing towels may have been a mode of transmission between the players as the relative risk among those with shared towels was 8.2.  Other factors explored, and found to be not significant, were sharing of soap and protective equipment, and not laundering uniforms.

Previous studies have shown that player position is often associated with increased risk of MRSA infection during an outbreak, as is increased BMI, but only BMI appeared statistically significant during this particular case.

MRSA is responsible for a high mortality rate among infected, as mentioned by revere at Effect Measure in a recent post about a study in PNAS by Aetiology blogger where MRSA is found in a pig farm in the United States.    The strain in the pig case (ST398) is different then the strain in this particular pigskin case (US300).

MRSA is the current superbug, and concern about spreading through fomites (in hospitals and lockerrooms alike) is only going to increase.

 

Trachoma

So I went to an interesting talk on the role of water and sanitation on incidence of Trachoma, and for the first time in recent memory, somebody besides me used the word “fomites”.  So I naturally wanted to blog all about it.

Trachoma is an infectious eye disease caused by Chlamydia trachomitis.  [Side note: inour lab safety training, the safety coordinator tells a story about how she got Chlamydia in her eye when she was working in the lab]  A typical infection, which lasts for 5-12 days, causes conjunctivitis-like symptoms, with eye inflamation leading to irritation and discharge.  If you visited the poorest of regions in Africa, Asia, the Middle East, and/or Latin America, and ended up with Trachoma, it’d be no big thing.  Your doctor would hand you antibiotics like he always does and you’d keep on walking.  But the locals who are continually re-infected with Trachoma end up with permanent blindness.  The constant inflamation from repeat infections leads to entropian, a painful form of blindess, which (according to Wikipedia) is the leading cause of infectious blindness.

Gross.

So trachoma is spread through contact with eye, nose, and throat secretions.  Either by direct contact, indirect contact via fomites, or indirect contact via vectors (like flies and cattle).  People who like the F-diagram say it is spread through feces, flies, fomites, and fingers.

The fomites in question are thought to be items like towels, but the speaker mentioned that the cloths women use to wrap and hold their babies [is kitenge the right word?  When i Googled it, i just got a bunch of photos of the whitest people wrapping random African-looking cloths around themselves and their sun-deprived babies,  so there's probably a better word out there] rubs right against the baby’s eyes, allowing discharge from one infection to continually cause reinfection.

So secretions appear to be the main form of transmission, but the speaker’s premise for the talk was that sanitation would reduce incidence of Trachoma because it would remove feces from areas where individuals and flies had access.  In general, promoting sanitation is always a great thing, but I’m not completely sold on its usefulness in combating an infectious disease spread through secretions.

And, perhaps, neither are the individuals at WHO working on its elimination who apparently rely heavily on the use of antibiotics to treat individuals, instead of trying to interrupt the transmission pathway.

 

Triclosan – Where Microbiology and Toxicology Collide.

Hitting the innerwaves today, care of ES&T,  is an article on EPA’s approval of Triclosan.   Triclosan is found in a large number of consumer products (e.g.  soaps, detergents, deodorants, mouth wash, and toothpaste).  Colgate Total, for example, contains triclosan to prevent gingivitas.

Triclosan is an antibacterial that binds to an enzyme in bacteria that is used to build fatty acids, a necessary component in bacterial cell membranes.    Notice, I said that it is an antibacterial and not an antibiotic.

Triclosan’s efficacy in hand soap is debatable.  Some studies have shown that hand washing is not improved with the addition of triclosan, if the recommended 30 second social hand wash is followed.  Others contend that triclosan provides a residual on the hands that continues to work against bacterial contamination, useful in settings where people do not wash their hands completely or correctly.  Most consumer products, like cutting boards, table tops, and children’s toys, that bear the term antibacterial likely have triclosan imbedded in the surface.

Additionally, soap with high concentrations of triclosan (think 2% compared to the 0.5% found in consumer soaps) are used to decontaminate individuals exposed to MRSA.

So why is it news that the EPA extended triclosan’s approval?

1) There is some (ok, very little) concern about antibacterial resistance developing, which seems unlikely unless organisms currently resistant (such as P. aeroginosa) are able to transfer resistance to other species.

2) Triclosan degrades in sunlight to form byproducts in a class of compounds known as Dioxins, which bioaccumulate in fatty tissue and pose a threat to the reproductive, sexual development, and immune systems and are probable carcinogens.  With household use sending triclosan directly down the drain to the waste water treatment plant, it frequently ends up in surface waters where it becomes an environmental pollutant.

and 3) The ES&T article mentions, through Cathy Propper at NAU, that triclosan bioaccumulates and impacts nitrogen fixation in microbial communities and plants.

My take?  Totally not necessary.  Just wash your hands well.  Wash your cutting board well.  Your table top…  Why contribute to a problem we have no idea of the magnitude of for the sole benefit of maybe, possibly, protecting ourselves environmental bacteria?

We’ll see what the EPA says when it comes up again in 5 years…

 

Rethinking Flu Vaccination

Dr. Donald Miller at UW is recommending that everyone replaces the annual flu vaccination with vitamin D.   A large part of this is that Dr. Miller perceives the CDC’s Advisory Committee on Immunization Practices (ACIP) has a financial interest in the success of the flu vaccine.  This financial interest has manifested itself in the ACIP’s new recommendation to give the vaccine to children between the ages of 5-18, as well as the traditional recommendation of the elderly (50+yo) and small children (>6mo-5yo).

I know the ACIP is not driven by the greed of possible flu vaccine revenues.  I think they probably believe so highly in the efficacy of the flu vaccine that they are interested in not only promoting and increasing its use, but also about investing in it.  If I believed clean drinking water in urban slums was a priority, wouldn’t I both invest in urban drinking water facilities and try to get on the relevant panels?

Another concern of Dr. Miller’s is the potential ties of increased autism to increased vaccination, and Dr. Miller points out that the flu vaccine contains aluminum (linked to Alzheimer’s), formaldehyde (linked to cancer), and an unwieldy supply of mercury.  He also points to a NYTimes article on the reduced efficacy of the vaccine in the elderly, incorporating doubt that it would reduce the high percentage of flu deaths in elderly communities.

Anyway, the reason I bring this up is that I don’t think there’s anything wrong with a child between the ages of 5-18 getting the flu.  If I was in this age group right now, I would try to avoid the flu vaccine.  Without the occasional sick day, what is there to look forward to?

Conflict of Interest? Whenever I had a choice, I have avoided the flu vaccine.  I don’t know why, I just never thought it was important.  Dr. Miller’s article put some valid reasons to my prior incoherent argument.
UPDATE:  A possible rebuttal from the NYTimes for Dr. Miller (admittedly doesn’t mention vitamin D and colds, but…)

 

Google Search to Track Epidemics

Google makes an estimated 95% of its revenue from online advertising via AdSense.  Obviously, they’re going to do a phenomenol job connecting web searches with related advertising, which requires a lot of tracking the what, when, and where of interweb searches.  One of the byproducts they released to the public is Google Trends.  Since my thesis centers around gastrointestinal illness, when I first heard about it, I plugged in “rotavirus”.

Seasonal Variation in Google Search Term "rotavirus".

This shows a surprisingly seasonal trend.  Fourier analysis on the trend in the search term (using data gleaned through digitization for the 2004-2006 seasons, the only information available the last time I did this) showed Cp peaks at 204 and 345 days.

Why?  I can think of two reasons.  One: media sensationalism warns of upcoming Rotavirus epidemics because it is a predictable seasonal disease, causing an increased interest in using it as a search term.  Two: Doctors diagnose people with rotavirus as a possible cause for their gastroenteritis, and people are more interested in learning about it.

If the second case is true, then you have a real time, easily accessible, proxy for number of rotavirus diagnoses in a given region (in the above case, the entire U.S.).  Instead of requiring the headache of a giant linked database for doctors/nurses/patients to enter the disease incidence, you only need people to type in the search term “rotavirus” into a Google browser, and you have “logged” an incidence of inquiry of the disease.

Google, thankfully, has now caught on the link between interest in searching for an illness and level of the disease with Google Flutrends.

This is incredibly awesome.  But, there is a lot more to be done.  One of the major advancements would be moving away from the artificial and meaningless boundaries of states, and trying to push for a more geographically relevant mapping.  For example, with today’s travel plans, it is a lot more relevant to Los Angeles if New York City is having a flu epidemic than if Arizona is.  A good use of someone’s time might be developing meaningful boundaries based on interactions between people in those locations.  I don’t know if this has been done, but something similar has been proposed.

Additionally, this demonstrates the use of Google’s existing information infrastructure for web-based technology to implement an easy and efficient method of geographically databasing existing diseases.  How easy would it be to ask a nurse to open a website (say something like diseasetracker.google.org) and literally just type in the diagnosis (e.g. breast cancer).   Or, better, ask patients to log in from their homes to get more-spatially relevant data.  The tracker immediately logs the address located to the IP and the diagnosis.  Instant Illness-related GIS.  Privacy shouldn’t be a concern.  Google could obscure the location of the IP Address to within 10 miles to protect patient identification.  Even with only 10 mile resolution we would have a significantly better system in place to track clusters of disease.

What will they come out with next?

 

VF481

Purell has busted out the “Original Formula” label to distinguish the infamous hand gel from its successor.  The active ingredient of the original formula is 62% Ethyl Alcohol, which primarily acts to denature/coagulate proteins.  Bacteria, those evolving little buggers, can not become resistant to this mode of inactivation.  Ethyl Alcohol also dissolves lipids, so it works better on enveloped virus (e.g. influenza) then nonenveloped virus (e.g. norovirus, adenovirus, rotavirus).

The new formulation, Purell VF481, is showing a 4 log reduction of norovirus and adenovirus using the fingerpad test with infected stool to artificially inoculate fingers.  Concentrations of adeno-/noro- are determined using quantitative reverse-transcriptase, with the log reduction a comparison of concentrations on fingers before and after ABHS use.  Since this is working so well against non-enveloped virus, I wonder how it does against spore-formers.

I have no idea what the active ingredient is for VF481.   A Google Search of “Purell VF481″ only turns up about 170 listings.  The method of ethyl alcohol inactivation doesn’t mesh with increased virucidal activity.  I think there’s something else in there.

According to “Disinfection, Sterilization, and Preservation” by Seymour Block: for both bacteria and virus: methanol < ethanol < isopropanol < propan-1-ol.  Maybe that has something to do with it…

Anyway they’re already selling it (in Europe at least)… so I imagine the ingredient is listed right on the packaging.

 

Salmonella in Pet Food

I am a little late to the party on the contamination of pet food with Salmonella by a Mars, Inc. plant in Everson, PA.  But this may be an ongoing problem, as “71 people who have fallen ill since 2006″.  Keep in mind this is dry pet food only.  Canning wipes out microorganisms.

I’d like to point out CDC recommendations:

To prevent Salmonella infections, persons should wash their hands for at least 20 seconds with warm water and soap immediately after handling dry pet foods, pet treats, and pet supplements, and especially before preparing and eating food for humans.

These recommendations are the same for handling likely contaminated foodstuffs like raw chicken, even though this is fomes-mediated transmission, not foodborne.  The CDC also mentions feces as a source; this strain of Salmonella schwarzen-grunde can pass right through the gut of a pet without the pet showing signs of illness.  Animals are definitely not vectors in this.

The CDC states that children should be kept away from “pet feeding areas” and not be allowed to “touch or eat pet food”.  This added emphasis on children is because they are disproportionally becoming ill:  the median age is 8 months and six of the eight diagnosed are <2 yo.  This disparity is probably due to an increased likelihood of reporting.  Poor immunity probably also plays a large role. I doubt its level of activity or interaction with the pet food because I’d obviously expect that a greater proportion of adults are feeding their animals.  Adults who become ill are unlikely to make the connection with the dog food, and also unlikely to report to a doctor/hospital because of it.  Plus, I’d expect that children in the 2-5 yo age range are the most likely to  unintentionally eat pet food, not the <2 yo age range.   It would be nice to have information on this, though.  The route of transmission is probably pet food/feces-to-parent-to-child.

So, wash your hands.