Various bacteria
tsmith | November 15, 2007Two recent stories highlight the good and the bad when it comes to infectious disease prevention.
The good
Death rates for vaccine-preventable diseases are at an all-time low:
The study, by the Centers for Disease Control and Prevention in Atlanta, and published in The Journal of the American Medical Association (link), is the first time that the agency has searched historical records going back to 1900 to compile estimates of cases, hospitalizations and deaths for all the diseases children are routinely vaccinated against.
In nine of the diseases, rates of death or hospitalization…
tsmith | November 9, 2007 Tuberculosis in humans is most commonly caused by Mycobacterium tuberculosis, a slow-growing, waxy, rod-shaped bacterium. Transmitted primarily via the air when an infected individual coughs or sneezes, it's estimated that a third of the world is infected with this agent, which causes approximately 2 million deaths every year. Though most infections are asymptomatic, infection is becoming increasingly deadly, due both to the spread of highly antibiotic-resistant strains and due to the increasing number of individuals with both HIV and TB.
While M. tuberculosis is primarily a human…
tsmith | November 8, 2007 Both Mike and Revere have new posts up documenting swine as a new threat to human health (beyond the pork chops and bacon), via carriage of methicillin-resistant Staphylococcus aureus in these animals. Several papers have been published recently documenting high rates of MRSA carriage in swine in the Netherlands, and also have documented transmission of this bacterium from swine to humans. However, even more worrisome to me than the Dutch publications is a new one out in Veterinary Microbiology, showing high rates of MRSA in Canadian swine--and guess where we import about 9 million hogs…
tsmith | November 6, 2007 I've written a post or two (or a dozen) discussing science journalism--the good, the bad, and, mostly (because they're the most fun), the ugly. There was this story about how blondes "evolved to win cavemen's hearts." Or this one that completely omitted the name of the pathogen they were writing about. Or this one, where a missing "of" completely changed the results being discussed.
I ran across another glaring example yesterday, dealing interestingly enough with one of my favorite topics: chocolate, and bringing in an "omics" prospective to it.
The news story covered a recent…
tsmith | November 4, 2007Welcome to this month's edition of Pediatric Grand Rounds! Sit back with a cup of mulled cider and enjoy the best of the past month:
Revere at Effect Measure tells the tale of Streptococcus pneumoniae serotype 19A--a serotype that's not included in the current vaccine, but has increasingly found as a cause of ear aches in children.
Of course, in addition to ear infection, 'tis the season for influenza. As such, it's timely that Highlight Health, Walter emphasizes the importance of influenza vaccination.
My own addition to this month's carnival touches on similar themes: how kids'…
tsmith | October 31, 2007Salmonella species are frequent human pathogens. An incredibly diverse genus, different types of Salmonella infect an enormous variety of species, from mammals to fish to invertebrates. They are typically acquired via ingestion of contaminated food or water, and the bacteria then seed the intestine and replicate there. These gram-negative organisms are the cause of typhoid fever (Salmonella enterica serovar typhi) and can also cause acute gastroenteritis (multiple types, including Salmonella enterica serovars enteritidis and typhimurium).
Of these types, S. typhi is the most deadly, and…
tsmith | October 18, 2007 A few news stories hit my inbox all at once yesterday--and the combination of them doesn't bode well for childrens' health; more after the jump.
First, despite several years now of banging the drum for having kids vaccinated against influenza, they're still being overlooked when it comes to pandemic planning:
Children would likely be both prime spreaders and targets of a flu pandemic, but they're being overlooked in the nation's preparations for the next super-flu, pediatricians and public health advocates reported Wednesday.
The report urges the government to improve planned child…
tsmith | October 16, 2007Busy day here, but I do have a brief post up on MRSA over at Correlations if you're looking for some reading material.
[Edited to add: Mike has a lot more new MRSA stuff here; well worth reading!]
tsmith | October 15, 2007Being a microbiologist can be a dangerous business. Some of us work out in the field, exposed to weather, animals, and pathogens of all different forms. Some do research in countries with unstable governments, collecting samples and tracking down infected individuals in the midst of strife, poverty, and warfare. Some remain in the lab, but share it with agents that can be handled only under high levels of containment, and may need special labs and permits just to do their research. We all realize our job contains some level of risk, and do what we can to minimize that.
However, as much…
tsmith | September 27, 2007 I asked yesterday what readers considered the most important diseases in history. This was prompted by a new ASM Press book, Twelve Diseases that Changed Our World, written by Irwin Sherman.
As I mentioned, Sherman included many diseases readers expected--plague, cholera, tuberculosis, smallpox, syphilis, malaria, influenza, yellow fever, and AIDS. He didn't include a few that popped up repeatedly in the comments--leprosy, measles, and typhoid (or typhus, for that matter). While I think a study of these could have been illuminating (especially leprosy, since much of the stigma…
tsmith | September 13, 2007Clostridium difficile is an emergent bacterium. A close relative of the bacteria that cause tetanus and botulilsm (Clostridium tetani and Clostridium botulinum, respectively), C. difficile is an intestinal bacterium that can cause colitis. C. difficile has until recently been a fairly rare cause of disease, and then only typically within a hospital setting. However, the emergence of a new, highly virulent strain of the bacterium a few years ago, coinciding with an increase in the rate of serious infections it caused, put this pathogen on the map. And like methicillin-resistant…
tsmith | September 12, 2007I mentioned that it's microbiology week at fellow Scienceblog Deep Sea News. Today's post over there is on "bioprospecting" in the sea--looking for naturally-produced chemicals that we can harness for employment as drugs or other uses. For example:
Over the last 20 years at Harbor Branch Oceanographic Institution we have developed a culture collection containing 17,000 bacteria and fungi from deep-water marine invertebrates and sediments. We have shown that the collection contains many unusual microbes which are not known from the terrestrial environment and are fermenting the isolates to…
tsmith | September 7, 2007 Or something like that.
I rarely watch TV, but one of the few things I watch every now and then are reruns of the multiple incarnations of Law & Order shows when I run into them on TNT or one of those cable stations. They have all kinds of "ripped from the headlines" story plots, but this is the first time I can recall where a news story was ripped from L&O (well, except that it takes place in Danbury, Connecticut instead of Manhattan):
Two people in Danbury have been infected with anthrax contracted from animal skins.
Officials say Ase-AmenRa Kariamu contracted 'cutaneous anthrax…
tsmith | September 6, 2007While E. coli typically makes the news as a food-borne pathogen, that's only one facet of the bacterium. It can be deadly, sure, but it also helps us digest our food; it produces vitamin K for us; benign strains can even protect us from invading pathogens. It's one of the most-studied bacterial species and a "workhorse" for research in microbiology and molecular biology. We use it as a marker of fecal contamination in water, and it can even be used to produce insulin for diabetes patients. So it may come as no surprise that it may one day be a cavity fighter as well:
Imagine being able…
tsmith | August 24, 2007...and that's not just a comment on the weather here. The past few days have been packed. In addition to the work stuff, I've been gearing up for classes next week and getting my kids off to their new school year (and my son in kindergarten). It's always nice when hard work pays off, but it would be even nicer if it didn't all pay off in the same week. But of course, when it rains, it pours. In addition to the publicity for the HIV article, a Reuters story on my Streptococcus suis talk in Wisconsin came out earlier this week, and was mentioned in the ProMed email alerts yesterday:…
tsmith | July 27, 2007XDR-TB has been in the news quite a bit lately, largely thanks to Andrew Speaker's notoriety. Even though his TB was later re-classified as "just" multi-drug resistant (MDR-TB) instead of the initial extremely drug resistant (XDR) type, it did serve to raise awareness about the issues public health authorities face when dealing with something like tuberculosis--and where the gaps are in the control of its spread. (Indeed, a breaking story out of Taiwan shows how difficult it can be to enforce a travel ban).
However, while XDR-TB is rather new on the radar of the general public (and even…
tsmith | July 26, 2007 In terms of physical size, microbiologist Rita Colwell is a petitie woman. However, her distinguished research and service career has made her a giant in her field. Her research revolves around many aspects of water ecology, including the intersection of the environment and infectious disease (as I wrote about here following a talk she gave this past spring).
Much of her research has focused on Vibrio cholerae, including devising simple (and inexpensive) methods to remove the bacterium from contaminated water using cloth filtration. For these achievements and more, Dr. Colwell will be…
tsmith | June 26, 2007 Women do some rather insane things to achieve modern standards of beauty. We wear shoes that do terrible things to our feet. We don bras that dig into our chest and push our breasts into strange conformations. We slide on pantyhose to firm our stomachs, makeup to hide our imperfections, and hair dye to diminish our grays. And we have this strange habit* of yanking other body hair out from the root, be it our eyebrows, underarms, legs, or pubic hair.
Yes, I do have a point here (besides making men squirm). The August issue of Clinical Infectious Diseases has a forthcoming article…
tsmith | June 13, 2007 Over at The Examining Room of Dr. Charles, the good doc brings up another instance of quackery from an unexpected source: Dr. Henry Heimlich, originator of the Heimlich maneuver for choking. While that procedure has clearly saved many lives, Dr. Heimlich doesn't stop there--he advocates using his maneuver for drowning victims and asthmatics, neither of which have been scientifically proven (and indeed, major medical associations have spoken out against them). Dr. Charles also reveals that Heimlich also carries out other questionable research, including deliberately infecting HIV+…
tsmith | June 12, 2007 One of the most famous stories in all of epidemiology revolves around the very birth of the science, in the midst of a London cholera outbreak in 1854. At the time, the scientific community was divided over the cause of cholera and other diseases. The majority of them accepted the miasma theory, the idea that disease was due to corrupted air ("all smell is disease," noted sanitation commissioner Edwin Chadwick). This idea dates back to antiquity, and increased in popularity in the Victorian era. It's a great example of something that logically made sense, even though it was wrong.…