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Answers to readers’ bacteria questions

November 22, 2013 — 
George Zhanel

George Zhanel

Dr. George Zhanel, a professor in the department of medical microbiology at the University of Manitoba, and the director of the Canadian Antimicrobial Resistance Alliance (CARA), answers some reader questions on everyday germs and antibiotics.


Why can’t I drink alcohol when I’m on antibiotics?

For some antibiotics you can’t, and for some you can. There are some antibiotics that if you physically take alcohol with them you get what’s called an antabuse reaction. The drug and the booze react and you get terribly sick. It’s a chemical interaction that you want to avoid.  Could you drink booze when you’re on penicillin for your sore throat? Sure. We don’t recommend it, but you could and nothing would happen. So as a general teach, we say don’t mix alcohol with antibiotics, but in practice, it‘s only a really bad idea with some drugs… and not a great idea for a lot of others. Talk to your pharmacist or doctor about mixing alcohol with your specific drugs.

Is it true we are so “clean” we are making ourselves sicker because we are lowering our exposure to bacteria?

I think that’s true. Back in the olden days your mother would tell you to go play in the garden or the barn or the sandbox, the thought was the more you were exposed to the fungi and the bacteria in the soil and the sand and the barn, your body was exposed to allergens and toxins and if it didn’t kill you it made you stronger – you developed tolerance. As we growingly try to remove children from these environments we are seeing a lot more allergies. Why? The kids have not been exposed to such a diverse breadth of allergens and toxins so they are less likely to build up tolerance and then when they are exposed to some stimulus they suddenly have asthma or allergies because we are not training their immune system – exposing them to many of these important human exposures. Is that affecting our ability to counteract superbugs or are we now more susceptible to superbugs? That, we don’t have any data on. I don’t know. But we do know if you don’t train the immune system early, you are more likely to have allergies. If you train it early, are you less susceptible to infection? I would think theoretically the answer is yes.

If you have a young healthy child, I think it’s a good idea to get them exposed to playing outside.

Does body fatigue increase your chance of bacteria having an impact. I sometimes find when I’m stressed I’m more likely to get sick, or I suddenly slow down to relax on a vacation and boom, I’m suddenly sick.

Twenty years ago I would have said “no, that’s just a myth, there is no data to support that.” But for many years I have been a visiting professor in Europe and there, they tackle infections differently than we do. We tackle infections with getting antibiotic on board to handle the infections. They are more into giving drugs that stimulate the body’s immune system to help fight the infection. The European teaching is that as you get tired, stressed, and overrun with life, exposed to extreme cold or heat, these stresses affect your body’s immune system and as you get tired and run down, your immune system will become less able to protect you from a cold, or influenza, or some sort of bacterial infection and perhaps now you are more susceptible to those infections. Our traditional teaching has been that we don’t think that’s really true or well proven, but I can tell you I hear this story over and over. Growingly I think there is something to it, that being stressed makes you more susceptible to infection because your immune system is less able to protect you. There’s not a lot of hard science to back this up, but I think there is an element of truth there.

Can I re-use Ziploc bags?

Personally I would throw out the Ziploc bags daily and the reason is that you grab a bag, you put some food into it for the day, and you know that whatever you’re putting into that bag has bacteria and fungi on it. And by handling them, all you’re doing is introducing more organisms into that bag. The risk of that bacteria in the Ziploc bag causing infection that leads to diarrhea of vomiting is very small, but it is there because the bacteria will live in that bag. You just gave it a food source and you will never get out every microscopic piece of food. And every time you introduce more food, you just get more bacteria. Do I know of a study that says throw out the bags and you get less infection? I don’t. But intuitively, especially if I’m putting in meat or cheese in it– meat and cheese love to grow bacteria — I am very worried and I would dump it. If I’m putting in pretzels or crackers or other dry goods, it’s less of a threat but it’s a good idea to now and then change them. If you really can’t bring yourself to change a bag often, wash it out and let it dry completely.

What should I use to clean my house?

People have been asking this for a long time. We know that vinegar is an unbelievably powerful substance in terms of killing organisms. Vinegar is acetic acid — bacteria, fungi and many viruses hate acids. Vinegar and water may smell a bit but it does an excellent job of washing counters and utensils. I don’t like a lot of fancy chemical cleaners because a lot of them are antibiotics and the organisms that cause infections in us can adapt to any type of antibiotic like substance such as household cleaners. Bacteria can use what we call “Efflux Pumps” which just pump the substance out of them. They use that same pump to pump out antibiotics that we use in patients such as penicillin. So if you’re training them to pump out these chemicals, you’re training them to pump out drugs in the hospital. Regular soap is great because you can’t develop resistance to soap, it emulsifies them. It blows them up. You can’t develop resistance to it.

What kind of hand soap should I use?

What I do is look to see what’s in the antibacterial soap. If I see there is a soap-based active ingredient, that emulsifies the bacteria, I know resistance won’t occur. If it is an alcohol-based product, it’s fine. Alcohol is amazingly effective at killing a whole bunch of different bacteria, viruses and fungi. Organisms don’t develop resistance to alcohol. But when I see some of these fancy things like quaternary ammonium compounds – bacteria love to develop resistance to them. I avoid those and tell people not to buy that kind of antiseptic or disinfectant.

Should I use Polysporin or Vaseline on a wound?

The moment you bypass the skin with a burn or a cut or a scrape, the healthy organisms that live on the skin can now get past the protective barrier of the skin and they get into the subcutaneous tissue. Polysporin will be fantastically effective at killing those bacteria and working with your immune system to cure the infection. If you simply put Vaseline on there, it may work, because your immune system will try to protect you and the Vaseline theoretically prevents the organisms from breathing oxygen because you occlude them. But some of these organisms can breathe without oxygen – they can breathe anaerobically and continue to cause infection. So for me, if I had a wound that looked like it was infected, I like Polysporin. I like it because one of the active ingredients is a drug called polymyxin. This is an old drug from the 1950s, which is a fancy peptide that inserts itself into the cell membrane of the bacteria and punches a huge hole in the bacteria, allowing things to leak in and out and the cell dies. Organisms can’t develop resistance to that because it’s like you are coming in with a big auger and boring a hole it in all over the place.

Research at the University of Manitoba is partially supported by funding from the Government of Canada Research Support Fund.


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