Various bacteria
tsmith | April 16, 2008This is the sixth of 6 guest posts on infection and chronic disease.
By Courtney Cook
Kidney stone disease affects approximately 5% of Americans. While several risk factors are well-established, including genetic predisposition, metabolic diseases, lifestyle, and diet, there are still questions over the actual mechanism of calcium stone formation. Many cases do not have any kind of underlying disorder and therefore it is difficult to know how to treat these patients to prevent further stone formation.
This seemed to change when, in 1998, Kajandar and Ciftcioglu isolated an unusual…
tsmith | April 15, 2008This is the fourth of 6 guest posts on infection and chronic disease.
By Ousmane Diallo
Last week in class we tackled an interesting topic, the role of Mycobacterium Avium Paratuberculosis (MAP) in the genesis of Crohn's disease (CD) and ulcerative colitis (UC). The authors Saleh E. Naser (oops the name means in Arabic 'The virtuous helper') and colleagues detected using Polymerase Chain Reaction (PCR) techniques in a lab based case controls study "viable MAP in peripheral blood in higher proportion of individuals with Crohn than controls". Not surprising after all since the pathology of…
tsmith | April 14, 2008 This is the first of 6 guest posts on infectious causes of chronic disease.
By David Massaquoi
Is this the Beginning of the end of antibiotic resistant problem or just another scientific false hope of eradicating microorganisms that have co-existed with humans for millions of years? In the days before antibiotics, some researchers saw bacteriophages, viruses that can seek out and destroy bacteria, as a promising candidate for fighting infections. Now, as more organisms develop resistance to existing antibiotics, phage research is finding new favor.
(More after the jump...)
At the Society…
tsmith | April 11, 2008 I don't understand how some segments of the population believe that "natural" always equates to "better." I certainly get the appeal of being close to nature; the romanticism of living simply and from the earth. I grew up and live currently in a rural area where people are close to animals and the land. But I also know that some of the most deadly poisons in the world are "natural." I know that, while most microbes out there are harmless, and many are even helpful, there are many that can make you violently ill as well. After all, tetanus, anthrax, and Ebola are all "natural."…
tsmith | April 3, 2008Early this week, grant application; yesterday and today, IRB and IACUC for another project. But once again, fellow Sbers are keeping me busy reading about stories I'd like to be writing on; see yet again Mike on E. coli O157:H7--everything old is new again; Ed on a new study showing yet again how amazing bacteria are; and DrugMonkey discussing heroin addiction as a family legacy, and notes that this sad story again shows that Narcan saves lives.
tsmith | March 19, 2008
Did Yersinia pestis really cause Black Plague? Part 1: Objections to Y. pestis causation
Did Yersinia pestis really cause Black Plague? Part 2: Examination of the criticisms
Did Yersinia pestis really cause Black Plague? Part 3: Paleomicrobiology and the detection of Y. pestis in corpses
Did Yersinia pestis really cause Black Plague? Part 4: Plague in modern times
Did Yersinia pestis really cause Black Plague? Part 5: Nail in the coffin
tsmith | February 29, 2008
I really need more time to fill in a gap in my microbiology education: environmental microbiology. I run across papers all the time that are absolutely fascinating, and wish I had a free year to just take some additional coursework in this area. For instance, a paper in today's Science magazine discusses how atmospheric bacteria result in the formation of snow; more after the jump.
The authors here were looking at ice nucleators (IN) in snowfall. Think of this like crystal experiments you did as a kid--you had to stick something into the solution to serve as a seed for the crystal to…
tsmith | February 27, 2008This is the fifth of 6 guest posts on infectious causes of chronic disease.
By Rachel Kirby
There are about 500,000 (or approx 1 in 544 people) in the United States who suffer from Crohn's disease, and is most prevalent in both men and women between the ages of 20-30. Crohn's Disease is an autoimmune disease which causes a chronic inflammation of the digestive tract. It can affect the entire digestive tract but is most prevalent in the lower small intestine and in the ileum. It will cause swelling, causing pain and diarrhea.
More after the jump...
Though a lot is known about the disease;…
tsmith | February 26, 2008This is the third of 6 guest posts on infectious causes of chronic disease.
By Whitney Baker
While working out at the gym last night, I was perusing the latest SHAPE magazine to help pass the time. In it, I read a small article about researchers finding an association between Adenovirus-36 and human obesity. Since I am in the infectious disease field, I was already aware of this proposed link- an infectious cause (or contributor) for obesity. But for the millions of health-conscious readers hearing of this for the first time, what would they make of it? Would they have visions of…
tsmith | January 31, 2008You're probably familiar with the Seinfeld episode where George commits yet another social faux pas, getting caught "double-dipping" a tortilla chip. Just in time for your Superbowl festivities, turns out a soon-to-be-published manuscript (described in the New York Times) examined just how many bacteria are actually transferred by "double-dipping." I have more at Correlations, and the Seinfeld clip is after the jump.
[Edited to add: Steve uploaded the poster describing the research here.]
tsmith | January 28, 2008 An ongoing outbreak of Salmonella associated with turtles has now sickened more than 100 and caused a quarter of that number to be hospitalized:
Cases have been reported in 33 states, but mostly in California, Texas, Pennsylvania and Illinois. Most of the patients have been children.
No one has died in the latest outbreak, which began in August. But some patients have experienced severe symptoms, including acute kidney failure.
The most common symptoms reported to the CDC included bloody diarrhea, abdominal cramping, fever and vomiting. The median age of patients was 7 1/2 .
More after the…
tsmith | January 23, 2008 Though there still may be some lingering doubt about the cause of the Black Death and subsequent outbreaks of plague, the pathogen behind the outbreaks that have taken place in the last 150 years or so is much less ambiguous.
While Koch and Pasteur ushered in the golden age of microbiology, an outbreak of plague began in China and spread from there. In 1894, while plague was raging in Hong Kong, the Pasteur Institute sent Alexandre Yersin, a physician who had trained with both Pasteur and Koch, to investigate. Yersin was able to access material from a corpse, and inoculated material he…
tsmith | January 18, 2008 In parts one and two of the "What caused the Black Plague?" series, I discussed objections that had been raised to the conclusion that the bacterium Yersinia pestis was the cause of this pandemic, and the weaknesses with those criticisms. In today's installation, I'll discuss actual molecular evidence that Y. pestis indeed caused this--and does this research shut the door on alternative hypotheses? More after the jump...
Much of the evidence for or against hypotheses supporting any pathogen as a cause of an ancient disease are based on symptoms and historical records. While we can…
tsmith | January 17, 2008 Yesterday I introduced criticisms that have been raised against Y. pestis causation of the Black Death and subsequent plague outbreaks. Today I'll discuss what I see as weaknesses in these criticisms, after the jump.
Selective quoting and interpretation of evidence
First and foremost, a big issue I have with the claims by Duncan and Scott are that they are rather selective in what evidence they choose. For example, they selected several quotes from medieval manuscripts and diaries that suggest that people at the time "knew" it was directly contagious from person to person, and…
tsmith | January 16, 2008 Methicillin-resistant Staphylococcus aureus (MRSA) has taken up residence in sport teams, prisons, schools, the military, and even swine. A new article in the Annals of Internal Medicine shows that, at least in Boston and San Francisco, it's also causing a lot of infections in men who have sex with men; more after the jump.
To examine this, the authors looked at MRSA infections from a variety of health care settings: medical centers, community health clinics, HIV clinics, and emergency rooms. These were examined in separate analyses. For example, for the medical centers they looked at…
tsmith | January 16, 2008 As I noted last week, Shelley mentioned a topic that's been brought up here a few times in the comments section: alternative theories for causes of the Black Plague (the devastating plague that ravaged Europe beginning in ~1347 and eventually killed more than a third of the population). Though the bacterium Yersinia pestis is almost universally accepted as the causative organism, like many areas of science, there are a few individuals who disagree with the consensus. To this end, several alternative etiologies for Black Plague have been put forth, and shortcomings with the mainstream Y.…
tsmith | January 16, 2008Did Yersinia pestis really cause Black Plague? Part 1: Objections to Y. pestis causation
Did Yersinia pestis really cause Black Plague? Part 2: Examination of the criticisms
Did Yersinia pestis really cause Black Plague? Part 3: Paleomicrobiology and the detection of Y. pestis in corpses
Did Yersinia pestis really cause Black Plague? Part 4: Plague in modern times.
tsmith | January 15, 2008 Some infectious agents, it seems, have been with us since the rise of humanity. Bacteria like E. coli or salmonella don't appear to have one moment enshrined in history where they first appeared on the scene. They've probably long been with us, causing disease sporadically but not spectacularly.
Other agents, however, seem to make their presence known. Syphilis is one of these. The first recorded outbreaks of syphilis (caused by the bacterium Treponema pallidum subspecies pallidum) were documented in Europe in 1495. These weren't syphilis as we know it today. Currently, syphilis is…
tsmith | January 11, 2008I'll have new posts up here next week, but meanwhile, over at Retrospectacle, Shelley's made this week plague week. She introduces the topic here, and next dishes about plague fashion. Also in the comments, it's asked:
I recently heard that there is some doubt now that the Black Death may not have been bubonic plague. The doubt based on the speed of transmission, but no alternate disease was mentioned. Is there any other disease that matches the symptoms that could be a likely alternative?
Long time readers know that I've referred to this previously and promised to post on it, so if even…
tsmith | December 17, 2007 In my field, many things that cause the average man-on-the-street to get a bit squeamish or squicked are rather commonplace. My own studies include two types of bacteria that are carried rectally in humans (and other animals), so I spend an absurd amount of time thinking about, well, shit, and the lifeforms that inhabit it and collectively make up our normal gut flora. The vast majority of these species don't harm us at all, and many are even beneficial: priming our immune system; assisting in digestion; and filling niches that could be colonized by their nastier bacterial brethren.
It…