Salmonella and E.coli

Salmonella:

Get this - In 1996 1994 (thanks Kris for the fact check) 224,000 people in the united states were infected with Salmonella enteritidis after eating Schwan's ice cream (I'm glad I've never heard of that brand)! Why did this happen? Well, take note that Salmonella is commonly found on chickens (estimates reach nearly 80% for chickens infected with Salmonella, or Campylobacter), and that ice cream contains eggs. Now, Schwan's Ice cream making process, as far as eggs go, involves three factories:

1) an egg breaking plant: makes liquid egg
2) a processing plant: makes an ice cream pre-mix using the liquid egg from factory "1" and pasteurizes said mix.
3) The final Ice cream making plant: makes ice cream.

Unfortunately, in order to increase efficiency, Schwan's decided to use the same trucks that transported liquid egg from plant "1" to plant "2," to transport the pasteurized pre-mix from plant "2" to plant "3." Not a bad idea, but apparently nobody told the truck drivers to clean out their tankers before transporting the pre-mix, effectively nullifying pasteurization... DOH! From the New England Journal of Medicine, "Written procedures called for the washing of tanker trailers after the delivery of liquid eggs and specified that the interior of the tanker trailer was to be washed and sanitized and the outlet valve removed for hand cleaning plus sanitization before premix was loaded. Officials of the FDA and the Minnesota Department of Agriculture noted soiled outlet-valve gaskets, inadequate record keeping, and the lack of routine inspection of the interior of the tanker trailer." I guess that's how to get a quarter million people sick with dysentery.

E. coli:

Ever wonder why you should always get your burger "Well done?" E. Coli is present on the surface of meats, so when you cook a steak, in order to kill E. coli, you only really need to thoroughly cook the surface. The problem with ground beef is that you take that bacteria, originally just on the surface, and mix it all up inside the meat. So, don't eat pink burgers!

Jack in the Box learned this the hard way... A rare and particularly virulent form of E. coli (serotype O157:H7) happened to find it's way into their undercooked burgers, infecting 47 people. This is the same serotype of E. coli that caused the recent spinach scare. E. coli O157:H7 (a.k.a. EHEC for EnteroHemorrhagic E. Coli) is the main cause of Haemolytic-uremic syndrom, the main cause if kidney failure in children.

To see a cool video on how EHEC infects a cell go to: http://www.hhmi.org/biointeractive/disease/animations.html
scroll down and click on E. coli infection strategy. And while you're there, check out all the other cool videos about such topics as; Horizontal gene transfer "Bacterial conjugation" (as discussed in a previous post on antibiotic resistance), viral life cycle, recombination of viral genome, and HIV life cycle.

Santa Barbara Century Ride

See the route here: SB ride!

So here was the thought - Let's get 17 people from the triathlon team to ride from UCLA to Santa Barbara! We can rent out some wealthy person's guest house (thank you craigslist) and take the train back to L.A. (thank you amtrak)!

Well, we made it happen and oh what a success it was.

Now for some photos!

We applied sunscreen.











We fixed a flat tire whilst waving to Amtrak.








We laughed at the person who got a flat tire (Kelsey).








Some of us got very dirty (Kelsey again...).












And, we posed for numerous pictures... well most of us.

For more go to: Pictures!

Whooping Cough

Above: The characteristic "Coccobacillus" shape (stubby rods) of B. Perstussis

Pathogen: Bordetella pertussis (I guess pertussis means "violent cough")

A short history -

• 1906 - Jules Bordet and Octave Gengou are the first to cultivate B. pertussis. This is a very important step as in order to be prove an organism is the etiological cause of disease one must be able to isolate the bacterium in pure culture ( see Koch's postulates).
• 1930s - Development of a "whole-cell" vaccine. The first Bordetella vaccine was essentially killed B. pertussis bacteria. The dead cells were enough to illicit an immune response and cause activation and production of adaptive immune cells.
• 1947 - Childhood vaccination becomes routine. The DTP vaccine (Diphtheria, Tetanus, Pertussis) was very effective (90%).
• 1970s - Concerns about the vaccine arose. Common symptoms included redness, swelling, fever and pain (these are common with almost any vaccine). The main concern was a low frequency of seizures (1/100,00) that was associated but never proven to be caused by the vaccine.
• 1980s - Outbreak of pertussis in Great Britain where mothers were opting out of getting their children vaccinated.
• 1990s - A new vaccine is developed made of purified protein parts of B. pertussis. This vaccine undergoes several different permutations (Tripedia, Infanrix, Daptacel, Boostrix, and Adacel) reaching an efficacy level of 85%. Not quite as effective as original, but fewer side effects.

In the words of E.A. Mortimer, “Some people who go outside after a rainstorm and see frogs believe it rained frogs.” Unfortunately for many parents in Great Britain, the consequences of not vaccinating their children were much higher than the assumed risk of developing "vaccine related" complications. Many children likely died of the following Pertussis epidemic even though the vaccine was never proven to be the cause of any serious complications. Children weren'g vaccinated mainly because of a weak correlation with seizures. This historic example of the "correlation = causation" fallacy (For those who enjoy latin - cum hoc ergo propter hoc) reminds us to be careful about making such false conclusions. It makes sense to err on the side of caution, but it just so happens that the cautious side in this case was to immunize children from a highly virulent and communicable pathogen.