Field of Science

#MicroTwJC 49 Expanding the Genetic Alphabet


Recently scientists have achieved a feat the like of which has not been seen in billions of years, they have added new letters to the genetic alphabet of a living organism.  What did they do? How did they do it ? Is it too good to be true? All these questions, and more await.

#MicroTwJc 46: FtsZ placement in Bacterial cells



An In depth look at how bacteria divide in "FtsZ placement in Nucleoid Free Bacteria"!
Link: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0091984

Statistical Websites:
1-way ANOVA
http://www.danielsoper.com/statcalc3/calc.aspx?id=43
Tukey's Honestly Significant Difference
http://faculty.vassar.edu/lowry/hsd.html

Microbiology Twitter Journal Club Website for more details:
http://microtwjc.wordpress.com/

MicroTwJC 45: When Antibiotic Resistant Compete (A video presentation)

This summary of the latest Microbiology Twitter Journal Club is going to be different in two ways. Firstly, it's late. Secondly, it's a video. I noticed a while ago that my explanations of papers tended to end up longer than the papers themselves, and I decided to experiment. Here are the results

 

The Post Antibiotic Era will take your job away.

In 1934, The Los Angeles Milk Commission gave its employees devastating ultimatum- lose their tonsils or lose their jobs. When our antibiotics stop working, your employer may force you to make a similar choice; and they'd be right.
Infectious bacteria are developing resistances to our medicines at alarming rates, and we are entering a Post-Antibiotic Era. If you want to know how people will cope in this new era, the best place to look is in the past. In the era before antibiotics.
 In the early 1930's, scarlet fever and strep throat were much more common than they are today, and much more hazardous. In the worst case scenario, a sore throat could develop into full blown sepsis.
So when a report was published in 1931 describing 71 outbreaks of this disease that could be traced to one common factor, people paid attention. That common factor was milk contaminated with bacteria named Streptococcus epidemicus. These bacteria tended to infect the udders of cows, causing mastitis. Since the udders also happen to be where the milk was produced, bacteria inevitably spread to the milk.
Needless to say, these outbreaks needed to be brought under control.
That responsibility fell to the Los Angeles Milk Commission,  implemented a number of rules to prevent any more outbreaks occurring.
The first step was to find any dairy cows infected with the disease. Fortunately, there were already rules in place for this. Cows needed to be certified to be free of S. epidemicus, and any infected cows needed to be isolated from the rest of the herd.
Here is the problem. Both humans and cows could carry S.epidemicus. To control any outbreaks, the same restrictions that applied to cows had to apply to the humans who worked with them. Humans could carry S. epidemicus without any symptoms, and appearing perfectly healthy.
Out of a thousand employees tested, fifty were carriers. This was devastating. They could no longer be allowed to work, for the risk of them causing an outbreak was unacceptable. 
There were no available antibiotic treatments to allow these carriers to rid themselves of S.epidemicus, but that didn't mean there were no options. It was known at the time that S. epidemicus survived in human tonsils. If the tonsils were removed, then the bacteria would have nowhere to go, and die off.
In a quote from the Director of the milk commission:
"care is taken in each case to impress upon them that the procedure is not compulsory except that otherwise they must retire from employment at certified dairies"
Basically, the procedure was only compulsory if the workers wanted to keep their jobs.
Unsurprisingly, most of the workers chose to go through the operation.
But sixteen of the infected employees either refused to go through with it, or were refused on the basis of underlying health issues that could render such an operation life threatening. These people were forced out of their jobs, and any dairy in the area was given their details should they attempt to apply for another job in the milk industry. Essentially, they were blacklisted from the industry.
You can say it was cruel that employees were forced into this situation, and you're not wrong. But it was an awful dilemma, and one that is destined to repeat. In a world without antibiotics, people who become carriers of diseases may remain carriers for the rest of their lives. Through no fault of their own, these people will pose a threat to the rest of the population, and it will hurt their chances of working in certain jobs. Would you send your kid to a school where a teacher constantly infects their students with life threatening illness ? Or buy groceries from a man with chronic diarrhoea? Allow yourself to get treated by Typhoid Mary?

 None of those sixteen workers ever suffered any symptoms. They may spent their life working in the dairy industry, only to be cast aside. They at least had the option of getting surgery to prevent them from being carriers. Not all bacteria are polite enough to live solely within an easily removed organ. 
The Post-Antibiotic Era is coming, and it won't just affect "sick" people, it will have wider effects throughout society. If there is one lesson we can learn from this eighty year old paper, it is that you don't even have to be "sick" for bacteria to ruin your life.

*Streptococcus epidemicus is a defunct classification that tends to be refer to what would be called S. zooepidemicus these days, and S. pyogenes.

Bonynge C.W. (1934). Solution of the Streptococcus Carrier Problem *†, American Journal of Public Health and the Nations Health, 24 (10) 1031-1034. DOI: