What Complications Can Occur With HIV?

Study: Showerheads May Deliver Blast Of Bacteria

If the shower scene in Alfred Hitchcock's Psycho scared you, here's another reason to scream: A new study says that potentially disease-causing germs can get trapped in showerheads and grow into biofilm, or coats of slime that deliver a bacteria blast along with your hot water.

Bacteria may thrive in showerheads and could pose a problem for those with weakened immune systems.

Although the classic horror film gave legions of moviegoers a fear of showering, the new study shouldn't do the same, experts say. The bacteria probably don't pose a threat to most people, although they could be problematic for those with weakened immune systems.

Showerheads are dark, wet, and warm -- the ideal environment for bacteria that cause lung diseases to thrive. As we turn on the faucet to get clean, the showerhead may spray our bodies and the air around us with such opportunistic bugs as Mycobacterium avium and other germs known as non-tuberculosis mycobacteria, according to the new research in the Proceedings of the National Academy of Sciences.

In fact, levels of these bacteria are more than 100-fold higher than levels found in the pre-shower water, according to the researchers, who analyzed the germs in the biofilm of 45 showerheads from nine U.S cities, including New York and Denver. Health.Com: The most toxic places in your home

"If you are immune compromised or are susceptible to pulmonary infections, take a bath instead of a shower," says lead researcher Leah M. Feazel, of the University of Colorado, in Boulder. "If you are healthy and your immune system is functioning properly, you should not worry about the germs in your showerhead."

Mycobacterium avium, found in 20 percent of study samples, can cause lung infections in both healthy people and those with weakened immune systems, particularly smokers, alcoholics, people with chronic lung disease, and others with conditions that make it difficult to fight off infection. Symptoms include fatigue, a chronic dry cough, and shortness of breath.

The good news is that L. Pneumophila, the water-loving germ that causes Legionnaires' disease, was rare in the study. Only 3 out of 6,000 genetic sequences tested were L. Pneumophila. Legionnaires' disease is a severe type of pneumonia, and outbreaks have been linked to L. Pneumophila-contaminated water in large central-air-conditioning systems, whirlpool spas, and other sources of water droplets.Health.Com: Safer alternatives for bathroom cleaners

"[The study] is nothing to freak out about because most germs don't hurt you," says Philip M. Tierno Jr., the director of clinical microbiology and immunology at New York University Langone Medical Center. People come into contact with 60,000 types or groups of bacteria on a regular basis, says Tierno, who is also a clinical professor of microbiology and pathology at the New York University School of Medicine in New York City. "Only one or two percent are pathogenic," he explains. Health.Com: Never-get-sick secrets: Take a cold shower

That said, cleanliness is next to godliness. "The new study emphasizes the need for us to periodically get rid of biofilm on our showerheads," he says. Change the showerhead once a year or more frequently, like they do in hospitals, to prevent mineral deposits and biofilm, he suggests.Health.Com: The benefits of a steamy shower

Metal showerheads appear to be less likely than plastic showerheads to grow biofilm, according to the researchers. Tierno recommends taking a steel brush and good cleaning solution to wash out metal showerheads.

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All About Bacteria

Are There Consequences Of Performing Oral Sex On A Woman With Bacterial And/or Yeast Infections?

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Question:Are there any health risks for a man if he performs oral sex on a woman with bacterial and/or yeast infections? And conversely, is it possible for a man to harbor any bacteria in his mouth that can upset the bacterial balance or introduce bacteria into the vagina?

The literature states that women's symptoms of bacterial vaginitis (the discharge) may worsen after unprotected sex (as it does for me). Why is this? It doesn't worsen with protected sex. It makes one believe the problem is coming from the man's ejaculate. Can a man be a carrier of something that can contribute to a bacterial infection? If so, why is treatment for men usually not recommended?

Answer:It certainly is possible to transmit diseases by oral genital contact. Gonorrhea, for example, is a bacterial infection that causes not only a genital tract infection, but can cause a severe sore throat (pharyngitis). Herpes is transmitted easily by this route, also. Some women report yeast infections after receiving oral sex, but the mechanism of this is not clear.

I'm not sure why symptoms of bacterial vaginitis (or vaginosis) worsen after unprotected sex. It's possible that the introduction of 5 to 7 grams of fairly high quality protein may provide extra "food" for the bacteria. In any case, it's food for thought.

And remember, the basic rule for safe sex: "If it's wet and isn't yours, don't touch it."

By Dr. Flash Gordon

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Small, But Smart: How Symbiotic Bacteria Adapt To Big Environmental Changes

Studying the impact of the environment on animal evolution is no easy task, as most animals reproduce slowly and exhibit complex behaviors. However, microbiologists have an advantage: Bacteria reproduce rapidly, which makes them a much easier subject for studying evolution.

The Isthmus of Panama offers a natural experiment

Laetitia Wilkins and her team from the at the Max Planck Institute for Marine Microbiology in Bremen, Germany, studies bacterial evolution in a very unique scenario: the Isthmus of Panama. This landmass connects North and South America, thus separating the Pacific Ocean from the Caribbean Sea, and serves as an ideal location for observing "real-time evolution." The closure of the Isthmus, which took place 2.8 million years ago, caused significant changes in the marine environments on both sides. The Caribbean side became warmer, more saline, and nutrient-poor, while the Tropical Eastern Pacific experiences variable temperatures, strong tides, and high nutrient levels. These environmental differences forced marine life to develop different survival strategies.

Lucinid clams and their symbiotic bacteria: Partners in evolution

Lucinids are marine bivalves that inhabit both the Caribbean and Pacific waters surrounding the Isthmus of Panama. At least 400 million years old, the family of lucinid clams inhabits a wide variety of habitats, from beautiful beaches to the dark abyssal depths. Their secret to success lies within: Symbiotic bacteria live inside their gills and help them meet their nutritional needs, forming such a close relationship that these clams couldn't survive without their little companions.

Interestingly, the symbiotic bacteria don't seem to depend on the lucinids. They can also live freely in the sediment. This allows them to interact with other bacteria and exchange genetic material with them, through what's known ashorizontal gene transfer. This, combined with their fast reproduction, helps them adapt rapidly to their environment.

"We wanted to find out how these symbiotic bacteria adapted to the different environmental conditions on both sides of the Isthmus," says Isidora Morel-Letelier, who conducted the study as part of her doctoral thesis together with Benedict Yuen. To achieve this, the team traveled to Panama to collect lucinid clams and analyzed the DNA of the symbiotic bacteria in their gills to detect differences in their genomes.

Different adaptation in the Caribbean and the Pacific

Morel-Letelier discovered that symbiotic bacteria dealt with the challenge very differently on both sides of the Isthmus: Those in the Caribbean were able to fix nitrogen, whereas those in the Pacific lacked this ability. "Life is not possible without nitrogen. Because the Caribbean has very low levels of nitrate -- an easily usable form of nitrogen -, the bacteria need other sources of this nutrient. Their ability to fix nitrogen likely allowed them to survive there. On the other hand, Pacific symbionts didn't face this issue because their waters contain nitrate levels ten times higher than those in the Caribbean," Morel-Letelier explains.

And there are more genetic differences. The scientists from Bremen discovered unique genes that were present in the Pacific symbionts, but were absent in the Caribbean ones. For example, symbionts in the Pacific had the potential to synthesize gammapolyglutamate, which is a storage compound produced by bacteria during nutrient limitation, or electron-transferring-flavoprotein (ETF) dehydrogenases, which are produced in response to low temperatures and anaerobic conditions. "These genes likely help the symbionts cope with the Pacific's more significant seasonal changes in nutrients, temperature, and oxygen levels compared to the Caribbean," says Morel-Letelier.

New metabolic capabilities revealed a unique evolutionary journey

The Max Planck scientists also wanted to understand how the Caribbean symbionts acquired the genes required for nitrogen fixation genes. For that, they compared the genomes of symbionts across the Isthmus of Panama with other lucinid symbiont genomes from around the world. "It seems like their last common ancestor did not possess the capacity for nitrogen fixation. Most probably nitrogen fixation is a recent trait acquired only by symbionts that faced a nutrient-poor environment," explains Morel-Letelier. This finding highlights the critical role that the environment plays in shaping bacterial evolution. "Through horizontal gene transfer, lucinid symbionts likely obtained the nitrogen fixation genes from another symbiont lineage," notes Morel-Letelier.

Future investigations should focus on understanding the symbiotic relationship between these bacteria and their lucinid hosts. "It would be very interesting to know whether the new metabolic capabilities of the bacteria, such as fixing nitrogen, benefit the lucinid clams in their ability to survive in the environment, and whether clams actively select the bacterial candidates that are better adapted to live inside them," says Morel-Letelier.

"This study improves our understanding of the ability of bacteria to respond to environmental changes, which leads us to think that bacterial communities may already be adapting to anthropogenic changes, such as the flow of excess nutrients from agricultural fields into coastal waters," group leader Laetitia Wilkins comments.

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