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Microbiology

Chris Nyquist, MD, MSPH


 
I had my MMR in my youth, am I safe for life?

No vaccine’s effects last forever, but these three last a long time. Since the risk is low, you are probably safe; if you were exposed you’d probably have a mild case. Mumps is the weakest of the three, and there have been outbreaks of mumps recently in vaccinated young people in their teens; but the experts think we don’t need a booster at this time.

How long does the hepatitis shot last?

The common HepB shots (a series of 3) is thought to last a lifetime.

How come antibiotics don't work when you have a virus?

Antibiotics are chemicals made by a fungus or bacteria to kill other fungi or bacteria; some have also been chemically modified by scientists to be safer and more effective. They work on metabolic pathways that bacteria and fungi have, and people do not; so they are usually quite safe for us. Viruses have no such pathways, as they make your infected cells construct new viruses. So we must try to find drugs that exploit small differences between them and us; it isn’t easy, and the drugs are not as effective as antibiotics are.

Is there any truth to the "2" second rule when food is dropped on the floor?

Well, we’ll see when we talk about immunology, Tyler. I am personally in favor of a 30-second rule. Longer for pie, shorter for broccoli.

Do the same contaminations for milk in humans apply for cow meat?

Some do, but some organisms grow in milk but not meat. When meat is ground (hamburger) there is a lot of surface that can be contaminated if any part of the equipment is not perfectly clean; while solid cuts like steaks have much less surface, the interior can’t be contaminated, and the surface is usually seared; so they are much safer. I hate to say it, but the only truly safe hamburger is cooked well-done.

How long does a vaccination last, before you need to go and get another?

Each is different. The best place to go for this kind of info is always the Centers for Disease Control, CDC. http://www.cdc.gov/vaccines/recs/schedules/child-schedule.htm

How is a new infection created? What will decide if it’s a virus or bacteria?

We’ll talk about that in immunology, too. Any break in the body’s surface can let bacteria or viruses in. But also, some of them are strong enough that they can penetrate these barriers; usually it’s the mucous membranes. For example, if you eat eggs contaminated with the bacteria Salmonella, they may penetrate the intestine lining and cause an infection there. If you inhale droplets containing someone else’s virus, you may get a lung infection.

Is it possible to have a continuous good immune system or do you have to take immune boosters all your life?

We do recommend some boosters for older folks. You need flu vaccine every year, as each year it’s a different virus. We recommend chicken pox boosters for older folks to prevent the later form of chicken pox called shingles. There is a pneumonia vaccine for older people too.

If you are allergic to chicken are you still able to get the flu shot?

Not many people ae allergic to chicken; it’s usually eggs. If you had a reaction to a previous flu shot, or a positive history of egg allergy, you should probably avoid the flu shot.

What are some claims of raw milk improving immune function? In other words, how would raw milk improve immune function?

No way that we can see.

How true is it that people actually get "sick" from the flu shot?

The trouble is that most people get flu shots in flu season. Since maybe a quarter of everyone will get flu unless vaccinated in time, it stands to reason that quite a few people will get their shot when they are already incubating the virus. Since the shot takes maybe a week to begin to work, if they get sick in that time it’s natural to blame it on the shot. But it’s also wrong!

How do we treat infections from gram negative bacteria?

With antibiotics that attack the special pathways involved in assembling the gram negative type of cell wall.

What factors influence a virus entering the lytic vs. lysogenic cycles?

That’s a pretty specialized question for Mini Med School! So I suggest you start with a nice description from San Diego State: http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/phage/lysis-lysogeny.html

Do YOU use antibacterial household products?

Dr. N. certainly does: Clorox is good for heavily contaminated areas like toilets. Alcohol gel is good for hands anywhere, though soap and water is just as good if there is a sink handy. Dr. C. uses Listerine mouthwash occasionally, as recommended by his dentist.

Concerning flu shots, does it matter when you get them? I’ve heard that you should wait as late as possible since they don’t last that long. Is that true?

No, it’s pretty much on the contrary. There are already cases of the flu identified in the US and a few in Colorado, so now is the time to get the shot if you can (our campus, for example, will begin next week). The shots boost immunity for at least the entire flu season.