Posted on 01/28/2007 4:09:37 PM PST by blam
Source: Texas A&M Health Science Center
Date: January 28, 2007
Bacteria In Staph Infections Can Cause Necrotizing Pneumonia
Science Daily — Researchers at the Texas A&M Health Science Center Institute of Biosciences and Technology at Houston have discovered a toxin present in the bacteria responsible for the current nationwide outbreak of staph infections also has a role in an aggressive pneumonia that is often fatal within 72 hours.
"The virulence of CA-MRSA (community-associated methicillin-resistant Staphylococcus aureus) strains that produce the PVL (Panton Valentine leukocidin) toxin presents a nightmare scenario," said M. Gabriela Bowden, Ph.D., research assistant professor at HSC-IBT and co-senior author. "If the community-acquired strain establishes itself in the hospital setting, it will be difficult to contain."
The most common cause of staph infections, S. aureus is a bacteria found on the skin or in the nose of about 25-30 percent of people. It also can be the culprit in minor skin infections like pimples and boils, as well as major diseases like meningitis, endocarditis, toxic shock syndrome and pneumonia.
In their study, Dr. Bowden and her colleagues at the HSC-IBT Center for Extracellular Matrix Biology used mice to analyze S. aureus Panton Valentine leukocidin (PVL), a pore-forming toxin secreted by bacterial strains associated with both the current outbreak of CA-MRSA and necrotizing pneumonia.
CA-MRSA causes serious skin and soft tissue infections in healthy persons who have not been recently hospitalized or undergone invasive medical procedures, while necrotizing pneumonia destroys healthy lung tissue and can be fatal within 72 hours. With the PVL toxin, the bacterium also attacks infection-fighting white blood cells (leukocytes).
In the 1940s, the high mortality rate from S. aureus was abated by penicillin, but the bacteria soon developed a resistance. Methicillin provided new treatment options for infections in the late 1950s, but as of the late 1990s, it has become resistant.
In December, the United Kingdom had its first documented report of fatal necrotizing pneumonia cases caused by PVL-positive CA-MRSA. Eight hospitalized patients developed infections from CA-MRSA, and two died. It was previously believed the hospitals were free of these virulent strains of CA-MRSA.
Testing several bacterial strains, the HSC-IBT researchers learned PVL itself has an enhanced ability to disrupt cells in the body, and PVL-positive S. aureus has a greater capacity to attach to and colonize the lung, the latter resulting in necrotizing pneumonia.
"Our research shows in vivo that PVL is sufficient to cause pneumonia," Dr. Bowden said. "PVL-producing S. aureus overexpress other factors that enhance inflammation and bacterial attachment to the lung. These combined effects result in a vicious cycle of tissue destruction and inflammation, explaining the rapid onset and lethal outcome of this type of pneumonia."
Using these findings, the next step is additional studies to identify targets for potential development of therapies to treat S. aureus infections, including the PVL-positive strain.
"The present study underscores the aggressiveness of these strains and the urgent need to develop new strategies to battle these infections," Dr. Bowden said.
Other Science Express study contributors from the Center for Extracellular Matrix Biology were Magnus Höök, Ph.D., director and professor; Eric Brown, Ph.D., assistant professor (now at The University of Texas School of Public Health at Houston); Maria Labanderia-Rey, postdoctoral fellow; Vanessa Vazquez, graduate student; and Elena Barbu, graduate student. Florence Couzon, Sandrine Boisset, Michele Bes, Yvonne Benito, Jerome Etienne and François Vandenesch from the University of Lyon and Hospices Civils de Lyon (France) also contributed.
Grants from the HSC, French Ministry of Research, National Institutes of Health, and Neva and Wesley West and Hamill Foundations supported this research.
The Texas A&M Health Science Center provides the state with health education, outreach and research. Its six components located in communities throughout Texas are Baylor College of Dentistry, the College of Medicine, the Graduate School of Biomedical Sciences, the Institute of Biosciences and Technology, the Irma Lerma Rangel College of Pharmacy, and the School of Rural Public Health.
Note: This story has been adapted from a news release issued by Texas A&M Health Science Center.
"I also have a hunch that if ALL the case history of MRSA was correlated
there is some lifestyle or personal hygene issues. "
MRSA does seem to prosper anyplace where people are in close quarters
for prolonged periods of times. I read that the Los Angeles jail was
an outbreak site.
And I can't remember his name but one of the players on The Washington
Redskins also got MRSA and was at least out-of-commission for at
least a year.
Virulent staph germ once confined to hospitals emerging in jails, gyms and schools
http://www.freerepublic.com/focus/f-news/1586689/posts
ping
"The newspaper headline, which states that tea tree oil can 'wipe out' the hospital superbug did not reflect either the newspaper or research articles, both of which reported eradication rates of just 41% for tea tree preparations."
The above passage is from the link that you gave me.
MRSA is a serious bacterial problem, and 41% effectiveness isn't going to do much to keep from spreading.
MRSA isolation is not practical as a large percentage of people have it on their skin at any time. Each person that enters the hospital presents another potential exposure. This is why hospitals are so concerned.
MRSA infections are more prevalent in hospitals because people there are sick, which can compromise the immune system, or they have had injuries or surgery, which give the bacteria a route into the body.
As for your theory about hygeine or lifestyle, I disagree. They are finding MRSA in many places that you would not expect it. Locker rooms and fitness clubs are breeding grounds. Schools and playground equipment too. It is far more common than you seem to think. You might even have it yourself.
I use tea tree oil for many things. It is a great cleaner. I also add it to shampoo. And If you don't have time to give your dog a bath, just add a few drops to a spray bottle with water and spray it on the dogs coat. It works well on cuts and skinned knees just don't use it full strength on your face. I found diluting it is better for my daughter's scrapes. Its great stuff.
I agree with you.Once you have had it,a recurrence is very likely to happen again.I know nurses who have gotten it more than once.I hope you are alright now.
My oldest daughter was bite by a few spiders. She got meningitis and then MRSA. She has had to have these strange lumps removed from her legs since then. Doctors have told her they are MRSA related.
I went to the hospital to see my mother who had MRSA. They had taken the notice off her door to suit up so I didn't. When the nurse saw my sister and I visiting without being suited up she threw us out. She told us to go home , take off our clothes by the washer and wash them ASAP. We then took hot showers. However we folded our coats over the rail near my parrot's cage. A few hours later my parrot fell to the bottom of the cage and died. I think it was from the coats but never proved it. We never came down with the MRSA. However my mom never got rid of it and had more problems until she died. Nursing homes are filled with MRSA and I won't let my daughter bring my grandson there during winter months. At least we can visit outside when the weather is good. MRSA is some nasty stuff to deal with.
In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms Aaron Brady1, Ryan Loughlin1, Deirdre Gilpin1, Paddy Kearney2 and Michael Tunney1 1 Clinical and Practice Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, UK
2 Microbiology Department, United Hospitals Trust, Antrim, BT41, UK
Correspondence Michael Tunney m.tunney@qub.ac.uk
Received 8 February 2006 Accepted 19 June 2006
-------------------------------------------------------------------------------- The susceptibility of Staphylococcus aureus [meticillin-resistant (MRSA) and meticillin-sensitive (MSSA)] and coagulase-negative staphylococci (CoNS), which respectively form part of the transient and commensal skin flora, to tea-tree oil (TTO) was compared using broth microdilution and quantitative in vitro time–kill test methods. MRSA and MSSA isolates were significantly less susceptible than CoNS isolates, as measured by both MIC and minimum bactericidal concentration. A significant decrease in the mean viable count of all isolates in comparison with the control was seen at each time interval in time–kill assays. However, the only significant difference in the overall mean log10 reduction in viable count between the groups of isolates was between CoNS and MSSA at 3 h, with CoNS isolates demonstrating a significantly lower mean reduction. To provide a better simulation of in vivo conditions on the skin, where bacteria are reported to grow as microcolonies encased in glycocalyx, the bactericidal activity of TTO against isolates grown as biofilms was also compared. Biofilms formed by MSSA and MRSA isolates were completely eradicated following exposure to 5 % TTO for 1 h. In contrast, of the biofilms formed by the nine CoNS isolates tested, only five were completely killed, although a reduction in viable count was apparent for the other four isolates. These results suggest that TTO exerts a greater bactericidal activity against biofilm-grown MRSA and MSSA isolates than against some biofilm-grown CoNS isolates. --------------------------------------------------------------------------------
Abbreviations: CoNS, coagulase-negative staphylococci; ISB, IsoSensitest broth; MBC, minimum bactericidal concentration; MRSA, meticillin-resistant Staphylococcus aureus; MSSA, meticillin-sensitive Staphylococcus aureus; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide; TTO, tea-tree oil
Scroll down to results in the second paper and notice the rapid killing of all mrsa isolates within 3.5 hours. This is huge. Normally, a loading dose of vancomycin would require an entire life cycle of the bug to kill it.
Yes, Tea tree oil may only have an eradication rate of 41%-- but thats not the poing. Vancomycin has an eradication rate of upwards of 83%, but MRSA strains have developed resistance to vancomycin. A prokaryotic cell does not (as far as the literature is concerned) have the ability to generate a resistance to tea tree oil, except for its ability to generate pumps to pump the compounds out of the cell (which hasn't been shown).
In addition, if we're talking mrsa occurence in general, the majority of those infected and/or colonized present with dermatitis (a skin infection). Because tea tree oil can be applied topically, it is very promising to reduce this occurence, and also transmission from colonized hands of healthcare workers. To understand why a colonization redluction of 41% is so significant, you would have to understand the concept of "bacterial load" and environment, which is too complicated to get into here.
If you are a medic, I would highly recommend you carry tea tree oil hand sanitizer or lotion-- it will decrease the risk of you getting mrsa (not by 41%, but by much more than that because of the processes I mentioned above).
Oh, and as far as the hygeine point goes, I certainly believe this has truth-- mrsa would not exist if people weren't so careless about following antibiotic recommendations to the letter from their docs.
"The research article is a very poorly reported trial that provides limited evidence
Even the article didn't conclude what you say it does.
And your gibe about generating business for hospitals is so off the wall and so insulting, not only to medical care workers, but to the people who read the comment, that you should be ashamed.
I don't know!
No clue.
I do believe that antibiotics in any form are OVER used.
I don't know!
No clue.
I do believe that antibiotics in any form are OVER used.
Staph is very dangerous and people don't realize it - that is most people.
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