Acne: Bad and good bacteria identified

A genomic approach to comparing acne-ridden skin with clear human skin has revealed a bacterial strain that may protect against the disease. The work was published online February 28 in the Journal of Investigative Dermatology by Sorel Fitz-Gibbon, PhD, from the Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine, University of California, Los Angeles, and colleagues.

Four of 5 people in the United States develop acne at some point. Although dermatologists no longer blame blemishes on too much chocolate or fatty foods, commonly prescribed acne drugs such as benzoyl peroxide, antibiotics, and isotretinoin (Accutane, Roche) have been used for decades, although they are not ideal. Antibiotics are usually ineffective in severe cases, and isotretinoin both has adverse effects and is teratogenic.

Propionibacterium acnes is a dominant skin commensal that colonizes pilosebaceous units, in which certain strains are hypothesized to stimulate development of acne vulgaris. The population sizes of the bacteria are similar among individuals, but the proportions of different strains vary between people prone to acne and people with clear skin. Similar to Staphylococcus aureus, only certain strains of the bacteria are pathogenic.

The researchers sequenced bacterial genomes to better define the genetic compositions of the P acne component of the skin microbiome in acne-marked vs healthy skin. The strategy revealed "a previously unreported portrait of the microbiota of pilosebaceous units at the bacterial strain level," the researchers write.

Dr. Fitz-Gibbon and colleagues applied over-the-counter pore-cleansing strips to the noses of 49 people with acne and 52 participants with clear skin, sampling P acnes in whiteheads or blackheads. The investigators typed bacterial strains according to 16S ribosomal DNA sequences (ribotypes), assigning each strain an acne index based on prevalence among patients with acne. This approach identified 11,009 ribotypes, but only a few were abundant in either patient group.

Genome sequencing was the next step. Team members from Washington University in St. Louis, Missouri, sequenced the genomes of 66 previously unreported P acnes strains from the samples and compared 71 bacterial genome types overall. Author Shuta Tomida, PhD, also from the Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, David Geffen School of Medicine, identified DNA differences among the strains.

Beneficial Bacteria

Three genomically identified strains are of potential clinical significance. Two strains were discovered in 1 of 5 volunteers with acne, but rarely in clear-skinned people. Conversely, a third bacterial strain appeared to be common in healthy skin yet was rare in skin with acne, suggesting a protective role.

The findings may have practical applications, the authors write, such as the development of a probiotic topical preparation to favor the protective bacterial strain or drugs to selectively target acne-related bacteria. A simple skin test might predict whether a person has an increased risk of developing aggressive acne.

Further studies might address identifying host factors that contribute to acne and matching microbiome subtypes with clinical subtypes of acne, such as cystic, pustular, or inflammatory acne.

"By combining a metagenomic study of the skin microbiome and genome sequencing of this major skin commensal, this study provides insight into potential bacterial genetic determinants in acne pathogenesis and emphasizes the importance of strain-level analysis of the human microbiome to understand the role of commensals in health and disease," the researchers conclude.

Source: http://www.medscape.com/viewarticle/780020?nlid=28944_1301&src=wnl_edit_dail

Some probiotics effectively reduce common GI symptoms

November 8, 2011 (National Harbor/Washington, DC) — Mounting evidence is building a strong case for the use of probiotics, or "good" bacteria, to alleviate common gastrointestinal (GI) symptoms, such as diarrhea, bloating, and inflammation, according to several studies highlighted during a press briefing here at the American College of Gastroenterology 2011 Annual Scientific Meeting and Postgraduate Course.

In one meta-analysis, researchers from the Maimonides Medical Center in Brooklyn, New York, found that in 22 studies of more than 3000 patients, probiotic prophylaxis significantly reduced the odds of developing antibiotic-associated diarrhea and Clostridium difficile–associated diarrhea by about 60%.

In another meta-analysis, researchers from Beth Israel Deaconess Medical Center and Harvard Medical School, in Boston, Massachusetts, analyzed 28 randomized controlled trials in which more than 3000 patients received a single or a combination of antibiotics for various indications. In adult and pediatric populations, the preventive effect of probiotic use was significant, regardless of the species used and regardless of the antibiotic administered.

In the largest study to date on probiotics in a nonpatient population, researchers from the University of North Carolina at Chapel Hill evaluated the efficacy of Bifidobacterium infantis 35624, a probiotic that has relieved symptoms in patients with irritable bowel syndrome, to see how well it relieved abdominal discomfort and bloating in nonpatients.

The double-blind randomized placebo controlled study involved a 2-week placebo phase followed by a 4-week intervention phase, and was conducted at 10 clinical centers in the United States. More than 300 nonpatients who had experienced abdominal discomfort and bloating more than twice weekly, on average, for at least 3 months were included in the study. They had not seen a physician or received prescribed medication for their symptoms in the previous 12 months.

In contrast to previous clinical studies of irritable bowel syndrome patients, the researchers saw no statistically significant improvement in mean severity of abdominal discomfort or bloating after the nonpatient population took B infantis 35624.

However, an Irish group found that a nonpatient population receiving B infantis 35624 experienced significantly more bloat-free days.

The researchers hypothesized that microbial imbalance could explain the increased incidence of a wide range of inflammatory disorders. To test whether altering the balance between good and bad bacteria in the gut raises the immune regulatory response, which could lower inflammation, researchers from the Alimentary Pharmabiotic Centre at University College Cork, and Alimentary Health Ltd in Cork, Ireland, conducted a double-blind placebo controlled study. Their goal was to see if B infantis affects systemic proinflammatory biomarkers in patients with inflammatory disease.

The results of their study suggest that probiotics exert anti-inflammatory effects.

"By giving a specific probiotic orally, we could actually reduce the levels of these proinflammatory cytokines and actually enhance the production of an anti-inflammatory cytokine, which is the exact replication of what we identified in animal models and more basic models," said principal investigator Eamonn Quigley, MD, FACG, professor of medicine at the National University of Ireland in Cork.

Plasma levels of the anti-inflammatory cytokine interleukin (IL)-10 rose significantly in healthy volunteers and patients with psoriasis, but not in those who took the placebo for 8 weeks.

Plasma levels of 2 proinflammatory cytokines — tumor necrosis factor-alpha and IL-6 — dropped in all patients who received B infantis. C-reactive protein levels were also significantly lower in patients with psoriasis, ulcerative colitis, and chronic fatigue after treatment with the bacterium than after treatment with placebo.

Although not everybody who takes an antibiotic should also take a probiotic, the institutionalized elderly should, to minimize the chance of getting something like antibiotic-associated diarrhea or antibiotic-associated C difficile, said Fergus Shanahan, MD, FACG, a researcher involved in the Irish B infantis 35624 study, and professor and chair of the Department of Medicine at University College Cork.

Certain subsets of patients, such as those with cystic fibrosis or chronic urinary infections, who must take recurring courses of antibiotics might benefit from taking probiotics to minimize antibiotic-associated diarrhea.

"It's ironic that we would worry about taking an organism when we've got billions of organisms in the GI tract" and the amount is relatively small, Dr. Shanahan observed. Instead of worrying about drug toxicity in that population, "we're worried about something that has vanishingly low side effects. It can't be zero, but it is very, very low."

"If we paid more attention to prescribing antibiotics, we wouldn't have a lot of these problems," added Dr. Quigley.

According to Mark Mellow, MD, FACG, director of the Digestive Health Center at INTEGRIS Baptist Medical Center in Oklahoma City, Oklahoma, physicians aren't the only ones to blame for the indiscriminate use of antibiotics. Edicts from hospital compliance committees often establish rules that patients who come in with community-acquired pneumonia be placed on antibiotics soon after admission. These rules can have unintended consequences.

"Someone comes in with a fever and a cough and because there's not enough time to sort it out, they get put on an antibiotic," he said, whether or not they have a bacterial infection.

Dr. Quigley reports financial relationships with Alimentary Health, Norgine, Merck, Procter and Gamble, Movetis/Shire, Shire, Yakult, and Ironwood/Almirall. Dr. Shanahan reports a financial relationship with Alimentary Health Ltd. Dr. Mellow has disclosed no relevant financial relationships.

American College of Gastroenterology (ACG) 2011 Annual Scientific Meeting and Postgraduate Course: Abstracts P650, P120, P60, P283. Presented November 1, 2011.


Source: http://www.medscape.com/viewarticle/753108?sssdmh=dm1.732339&src=nldne

Nasty bugs lurking on your cell phone

Photo Credit: Ambro

By Tim Locke

October 14, 2011 — The next time you reach for your cell phone, consider this: A new study found that 92% of cell phones in the U.K. have bacteria on them - including E. coli -- because people aren't washing their hands after going to the bathroom.

The E. coli came from fecal bacteria, which can survive on hands and surfaces for hours.

Researchers from the London School of Hygiene & Tropical Medicine and Queen Mary, University of London looked at cell phones in 12 cities in the U.K.

They took 390 samples from cell phones and hands, which were then analyzed for germs. People were also asked about their hand hygiene.


Phone Filth and Other Facts
The study found:
92% of phones had bacteria on them.
82% of hands had bacteria on them.
16% of hands and 16% of phones had E. coli bacteria, which is found in feces.

However, 95% of people said they washed their hands with soap where possible, which suggests we have a tendency to lie about our hygiene habits.

"We're pretty shocked to find the vast majority of mobile phones -- 92% -- had bacteria all over them. Often large numbers of bacteria,” said hygiene expert Val Curtis, PhD, of the London School of Hygiene & Tropical Medicine.

"That isn't necessarily something that we should worry about, but what is worrying is that 16% of mobile phones had E. coli on them. E. coli comes from human [and animal] feces,” she says. "That means that people with dirty hands are not washing their hands after using the toilet, for example. Then they're handling their mobile phones.”

It’s not just cell phones that the dirty hands are touching, Curtis says.

"They're also touching other surfaces as well,” she says. “They're spreading fecal bugs on everything they touch really."


Toilet Texting?
Is there a more worrying way the phones are getting contaminated -- by people using them while they're in the bathroom?

"We didn't ask people whether they'd used their phones in the toilet. That might be something that would be interesting to study," Curtis says. "People do tend to use their mobile phones everywhere they go. Perhaps we should discourage their use in the toilet."

So is having unclean hands a modern-day problem linked to our new technology?

"Humans have had infections since before they were human. It's a really ancient problem," she says. "Bugs are evolutionary masters at getting from person to person.”

Anything that you touch can become a source of infection, Curtis says. So hand washing after using the toilet is crucial.


Excuses, Excuses
Curtis says people can be quick to excuse their nasty habits.

"They say that they're in a hurry, they say that the water's too cold. People don't actually feel that their hands have got contaminated.

"Everyone knows they should do it, so it's not education that's the answer. We need to find other ways to remind people that it's disgusting that their hands are dirty and their hands get smelly and foul after the toilet,” she says. "Disgusting people with the state of their hands is probably the most effective way of getting people to wash their hands."



SOURCE: http://www.medscape.com/viewarticle/751569?sssdmh=dm1.726554&src=nldne