AP Biology class blog for discussing current research in Biology

Are bad bacteria really bad?

That moment you finish pumping your gas and you think about all of the other hands that may have touched the same nozzle, so you become so disgusted until you remember that there is a bottle of Purell in the car. You suddely have the urge to open the cap, squeeze half of the bottle into your hand and rub them until your hands have never felt cleaner. The soothing idea that only .01% of bacteria may still lay on your hand rushes upon you and then you are able to go about your day picking up food with your fingers and proceeding to place it in your mouth.


Funny thing is, studies show that using Purell is not good for our hygiene. Does this mean that using Purell and  other anti-bacterial creams, sprays and medicine have actually been the cause of some of our ailments? Purell should not  be used on a day to day basis because it removes 99.99% of germs that means that you are not only killing the bad germs but also the good germs, and maybe leaving just .01% of them behind. Anti-biotics have a similar affect as Purell.


The hypothesis:

H. pylori in the stomach- photo taken from

Dr. Blaser, a profesor of microbiology at NYU, decided to research what are the consequences of killing all of the bad bacteria in the human body by using anti-biotics and anti-bacterial creams. He came upon the hypothesis that “the overuse of antibiotics increase the risk of obesity.”  He discovered that anti-biotics have been prescribed to patients with ulcers and gastric cancer, even when the patients showed no symptoms. These anti-biotics actually kill a bacteria called Helicobactor pylori (H.pylori). Studies show without H.pylori, a hunger hormone ghrelin, increases its secretion after a meal, when the hormone is actually suppose to drop in secretion levels. Thus by removing H. pylori the person is actually eating more frequently and consequently gaining more weight. It is also shown the children who have been treated with regular doses of anti-biotics to treat throat and ear infections had a marked increase in body fat while maintaining a constant diet. So can it be blamed on doctors that what they say is so-and-so “baby fat” is actually a result of their over prescription of anti-biotics when we had ear infections? Ok. maybe I went a bit to far, but it seems simple, some bad bacteria is meant to be in our system, not only to keep us healthy but also so that we can form some resistance to the bad bacteria.


By overusing anti-biotics we have created superbugs such as methicillin-resistant staphylococcus aureus. What a big word, what does it mean? Methicillin-resistant staphylococcus aureus is a bacteria better known as MRSA and is derived from a bacteria that was known to create staph infections. That bacteria was able to be treated through an assortment of anti-biotics but this new superbug does not respond to most anti-biotics. Thus more and more anti-biotics are being given to MRSA patients resulting in a large concern for obesity in these patients.

Back to the Hypothesis of Dr. Blaser: 

Yu Chen, an epidemiologist at NYU, has agreed with Dr. Blaser that the overuse of anti-biotics and the correlation to H. pylori has also been the cause of many childhood infections such as: hay fever, asthma, and skin allergies. Peter Turnbaugh, a Harvard University geneticist, and  Dr. Jeffrey Gordon, a gastroenterologist at Washington University in St. Louis have also agreed with Dr. Blaser that the use of anti-biotics alter the healthy ratios of bacteria in the stomach, which results in an on-set of weight gain.

This is just the start of Dr. Blaser’s studies, he was granted over 100 million dollars from the National Institute of Health and plans on researching more bacteria, not only H.pylori. SO, what does this mean? Can anti-biotics be killing too much bacteria? Should we be waiting until our sickness has reached its peak before we take an anti-biotic? What about Purell is that creating superbugs?

A solution may be to wash our hands before we eat, but not be too narcotic and kill all of the bacteria that may lay on our hands, what do you think?


For more information please go to:,33634.asp






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  1. nicleus2

    In your post, you talked about superbugs and how they get stronger the more we use hand sanitizers like purel. That sparked my interest, so I decided to do some research on how this phenomenon has to do with natural selection. I came up with an article that describes in detail how superbugs come about:

  2. biologiamaster

    Awhile ago i came across an article ( that warned of long term antibiotic issues.

    There appears to be emerging evidence that antibiotics cause permanent changes to our gut flora that we do not recover from, leading to susceptibility to infections and disease. Research even points to a connection between overuse of antibiotics and increasing rates of obesity, type 1 diabetes, inflammatory bowel disease, allergies and asthma, all of which have doubled in recent years.

  3. aminoalix

    WHOA! I feel like we have talked about this before. Even though your blog says that soap is the best way to clean hands, did you know that if you do not wash your hands “correctly,” the soap is not even extremely effective? I was researching and found this article on the cdc’s website. It can be helpful to hand-washers of any age! Check it out:

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