microbiology
sporte | August 5, 2007
It could be geosmin.
We encountered geosmin once before in our butter but most people notice it, about this time of year, in their tap water.
Geosmin is a volatile compound that's made by soil bacteria like Streptomyces, as well as some plants like sugar beets, and cyanobacteria. It gets blamed quite often for making water taste like dirt. Only a small amount is required (10 nanograms per liter) for detection by the human palate (1) and it's been blamed for adding a "dirt-like" taste to many things like water, wine, apple-juice, and catfish.
So, late in the summer when everyone is…
sporte | August 2, 2007What do malaria, sleeping sickness, yellow fever, and dengue virus have in common? Sure, they're all tropical diseases, but there's something else.
All of these diseases have some kind of insect vector.
image from the Public Health Library
tags: tropical disease, yellow fever, sleeping sickness, insect control,malaria
At one time, I thought it was merely a matter of an insect biting one organism and then transmitting the parasite to another organism because the parasite was stuck on the insect proboscis, or something like that, kind of like the way cold viruses might get transmitted…
mikethemadbiologist | July 31, 2007Massachusetts, which has one of the highest rates of childhood vaccination, is facing an increase in parents claiming religious exemptions from having to vaccinate their children, even though the number of kindergarteners has decreased. But these exemptions aren't actually religious at all:
Barry Taylor practices naturopathic medicine, and defends these parents' right to choose. "The truth is, it's not about their religion," Taylor said. "It's about their values. And it would be a bit of a white lie to say it's religious."
Proponents of parental choice want Massachusetts to add a…
mikethemadbiologist | July 24, 2007A colleague has told me about some interesting data that people are far less likely to request an antibiotic for a chest cold than for bronchitis even though they're the same thing. With that in mind, here's something from the archives.
One cause of the evolution of antibiotic resistance is the inappropriate use of antibiotics in clinical practice. A recent study concluded that antibiotic therapy did not result in eliminate bronchitis any faster than not using the antibiotic:
A study found that bronchitis sufferers who are otherwise healthy do not get better any faster by taking antibiotics…
mikethemadbiologist | July 23, 2007While lots of people swear by the power of tea, I had no idea it was seriously viewed as a something that led to urbanization. From The Ghost Map by Steven Johnson (p. 94-95):
The dramatic increase of people to populate the new urban spaces of the Industrial Age may have had one other cause: tea. The population growth during the first half of the eighteenth century neatly coincided with the mass adoption of tea as the de facto national beverage. (Imports grew from six tons at the beginning of the century to eleven thousand at the end.) A luxury good at the start of the century, tea had…
mikethemadbiologist | July 19, 2007Why can't you be nice to me?*
Look, I realize that Rick Perlstein's phrase 'E. coli conservatism' is a catchy way to describe the continuing breakdown of the national infrastructure. But that phrase bugs the crap out of me (pun intended).
I've noted before that most E. coli are harmless commensals--overwhlemingly, they do not cause disease. If they did, we would be sick all the time. Except immediately after certain kinds of antibiotic therapy, humans always have high concentrations of E. coli (around 1,000,000,000 per gram of poop, give or take a zero). Some cause disease, but there are…
mikethemadbiologist | July 19, 2007The Boston Globe reports that the Charles River swim race might be canceled because of cyanobacterial blooms. Again. So why is this happening? Phosphorous levels are too high:
Blue-green algae are not true algae, but cyanobacteria. They are usually present in amounts so small they are harmless, but can undergo exponential growth spurts when exposed to nutrients contained in contaminants such as lawn fertilizer and Canada goose droppings that wash into waterways.
State and federal environmental officials suspect that this year's bloom is occurring now because of optimal conditions for growth…
mikethemadbiologist | July 18, 2007Since I haven't discussed antibiotic resistance for a while, I want to put that health problem in context. The CDC estimates that every year, over 60,000 U.S. residents die from a hospital-acquired bacterial infection that is resistant to one or more commonly used antibiotics. Roughly 25,000 per year die from bacterial infections resistant to three or more antibiotics (e.g., MRSA). And that's just the infections you catch in the hospital. For a little perspective, HIV/AIDS kills under 18,000 U.S. residents per year. Antibiotic resistance is a serious, albeit neglected, problem.
Onto the…
mikethemadbiologist | July 11, 2007...and the Mad Biologist answers. Over at the World's Fair, David asks scientists:
1. What's your current scientific specialty?
Microbial population biology.
2. Were you originally pursuing a different academic course? If so, what was it?
Yep. I was originally a marine evolutionary ecologist. I studied botrylloid ascidians (specifically, the evolution of histocompatibility). Sadly, I had far more cache than a microbiologist.
3. Do you happen to wish you were involved in another scientific field? If so, what one?
Nope. Given the crappy wages, long hours, and work to get to the point where…
mikethemadbiologist | July 8, 2007The title is self-explanatory. From digby:
When the TB guy story was blazing I wrote that one of the most annoying things about it was that the guy said he was willing to put god knows how many other people at risk because he believed that he would die in a European hospital and had to get back to America where the health care was good. Aside from it being a thoroughly selfish act, it was just wrong. He would have had fine care in that Italian hospital and he could have arranged for transportation back to the states without endangering the lives of of all those strangers many of whom might…
mikethemadbiologist | June 23, 2007Anything that lowers the non-therapeutic use of antibiotics in agriculture is a good way to prevent the spread of antibiotic resistance. Fromt he NY Times:
Tyson Foods, one of the nation's largest poultry producers, said yesterday that it would no longer use antibiotics to raise chicken sold fresh in stores and would start a $70 million advertising campaign to promote the shift.
The company said that fresh chicken raised without antibiotics was shipped to stores Monday and would be sold beginning later this week in packaging that emphasizes there are no artificial ingredients.
"We're…
mikethemadbiologist | June 21, 2007In the May edition of Evolution, Hopi Hoekstra and Jerry Coyne have an interesting commentary, "The Locus of Evolution: Evo Devo and the Genetics of Adaptation." They raise two points about "evo devo" (the fusion of developmental and evolutionary biology) that have always bothered me. From the abstract (boldface mine):
An important tenet of evolutionary developmental biology ("evo devo") is that adaptive mutations affecting morphology are more likely to occur in the cis-regulatory regions than in the protein-coding regions of genes. This argument rests on two claims: (1) the modular nature…
mikethemadbiologist | June 19, 2007NIH, in about six months, will release a huge sum of money to fund the study of the human 'microbiome': those microorganisms that live on or in us. One of the things that will be done with this money is meta-genomics which is "the study of genomes recovered from environmental samples as opposed to from clonal cultures." (In this case, the samples would be fecal, vaginal, your mouth, etc.). In other words, we can sample the 'community' of genomes (or perhaps we should call it the community ecology of genomes). So I have a question: what do we learn from meta-genomics of the human…
mikethemadbiologist | June 17, 2007Here's a disturbing paper: "Can methicillin-resistant Staphylococcus aureus be found in an ambulance fleet?" The answer? Yes. From the abstract:
OBJECTIVE: To perform an initial screening study of methicillin-resistant Staphylococcus aureus (MRSA) contamination in an ambulance fleet. METHODS: This was a cross-sectional study of MRSA contamination in an ambulance fleet operating in the western United States in June 2006. Five specific areas within each of 21 ambulances (n = 105) were tested for MRSA contamination using dacron swabs moistened with a 0.85% sterile saline solution. These…
mikethemadbiologist | June 14, 2007The misuse of cefquinome has been a pet peeve of mine. Well, I have a commentary in ASM's Microbe about this topic: "Cefquinome: when Regulation Collides with Biology."
It might be boring because I don't use, erm, colorful, blogtopian language, but it still might interest you.
mikethemadbiologist | June 10, 2007I'm usually loathe to rip into a top-notch economist like Brad DeLong, especially when he titles his post "An Unrealistic, Impracticle, Utopian Plan for Dealing with the Health Care Opportunity." But several things bothered me about that post.
What I've never understood about the entire healthcare debate is the need to invent completely new plans. My take on this is ultimately pragmatic: find a system that provides universal coverage and good healthcare and institute it. Much of Europe--including the dreaded French--have very good healthcare. Translate the damn documentation, slap a big…
mikethemadbiologist | June 7, 2007I like much of Matt Yglesias' writing. But he still doesn't appreciate how science and evolution affect public policy issues. As many of you know, three out of ten Republican presidential candidates stated that they don't believe in evolution at one of the presidential debates. Yglesias comments on Huckabee's response:
I see that Jamie Kirchick didn't care for the reply at all: "Sorry, but if someone believes in fairy tales, I think that's pretty relevant to their qualifications as president." But why? The core of Huckabee's answer is here:
It's interesting that that question would even…
grrlscientist | May 31, 2007tags: tuberculosis, TB, Andrew Speaker, infectious diseases
Did you hear that the man who was infected with extensively drug-resistant tuberculosis (TB) is an affluent marital and personal-injury attorney? It turns out that this selfish, idiotic dope who should know better, went on his honeymoon through Europe, knowing he had TB. While overseas, the infected man, Andrew Speaker (pictured right; image source), exposed hundreds of people to his very dangerous strain of TB before finally returning to the United States -- against federal health officials' warnings -- by driving across the…
mikethemadbiologist | May 27, 2007From Monday to Friday, I attended the American Society for Microbiology meeting held in Toronto. Before I get to some of the interesting science, my apologies to all of the people who suggested we meet up. Unfortunately, I never look at the blog (or almost never) while I'm on the road, so I missed your messages (it's best to email me directly). Anyway, here's the list of random things:
The E. coli responsible for the spinach outbreak is found in many feral swine. Hence, feral swine are a possible reservoir of E. coli O157:H7. Of course, feral pigs roaming around California in significant…
mikethemadbiologist | May 25, 2007A couple of weeks ago, after I posted about a very serious emerging bacterial threat, KPC, I received an email from a reader with an elderly relative in the hospital with a very serious case of pneumonia caused by KPC. What he* told me is shocking.
The relative, who has had repeated hospital stays and a previous MRSA infection, was in the hospital for a week before any laboratory cultures were performed. That's right, a patient with practically every major risk factor for a multidrug resistant infection wasn't tested for a week. So this patient wasn't isolated, exposing other ICU patients and…