Category Archives: gross

Lemons, A Bacterial Reservoir?

Courtney Golden (11 AM Micro) found an article on Science Daily, which might stop you from eating your vegetables, or from drinking fresh lemonade. So not only do you have to wash your hands, you have to wash your lemons too. Here’s Courtney’s story:

They say, “When life gives you lemons, make lemonade!” Well you might just want to think twice about that lemon, especially when you’re out to eat at your favorite restaurant. Although iced tea with lemon, water with lemon, or even diet with lemon are very popular refreshing beverages when you go out to eat, the lemon could be spiking your drink with many bacteria and microorganisms. According to Jonathan Leff and Noah Fierer at the University of Colorado, Boulder, many different fruits and veggies that are often consumed raw, such as spinach, lemons, tomatoes, and others contain similar surface bacteria. These fruits and vegetables may have varying surface bacteria due to farm locations, storage conditions, and transportation conditions, but overall, similarities occur. The bacteria located on the surface of fruits and vegetables are not known to cause disease, but can be the source of typical microbes on kitchen surfaces. These bacteria are not the problem, the lemons sitting in your drinks, may have been exposed to more serious bacteria, which could eventually make you sick. ABC News reports a story concluding that fecal matter and E. coli were found on the surfaces of the lemons. Good Morning America tested lemons from six popular family restaurants. Although yeast and surface bacteria that are typically found on fruits and vegetables were cultured, four of the six samples contained fecal matter and E. coli. It was also found that the workers in the restaurants were not wearing gloves nor using tongs when handling the lemons to garnish the drinks or food. Director of Clinical Microbiology at NYU, Phillip Tierno stated that “A small risk, but a risk nevertheless by ingesting byproducts of these lemons.” Tierno also reports that, “I see that people have no concern of where they put their fingers, they’ll take things with their bare hands rather than gloving up and distributing the food stuff as they should.” Although Leff and Fierer report that the surface bacteria on fruits and vegetables can inhibit the growth of disease-causing bacteria, the lemons drowning in E. coli and other bacteria would not be out-competed by the normal flora on lemons.

Anne LaGrange Loving, an Assistant Professor of Science at Passaic County Community College also studied the contaminants on lemons. Loving collected 76 lemon samples from 21 different restaurants and found 69.7% of the lemons contained 25 different bacteria and yeasts. E. coli, family members of Enterobacteriacea, and other non-fermentative gram-negative bacteria were still found on the lemons even though their source is unknown. ABC News states that ways to protect you from getting sick are simply squeezing the juice of the lemon into the beverage instead of mixing the hide of the lemon into the beverage that is being consumed. On the restaurant’s side, gloves and tongs should be used avidly and more frequently. Like we have talked about in class, it can only take a certain special circumstance to infect a person with bacteria, especially with a gram-negative bacterial infection, which is worse due to the growing resistance to treatment from these bacteria. Anyway, who wants to drink bacteria infested lemon water? Not me.


Parasites in the human mouth


Pulled from his mouth!

Just in case you found the hypnotoad parasitism case gross, here’s one to top that. BIO230 correspondent Heather G found a link via Wired online, which summarizes a report from the American Journal of Tropical Medicine and Hygiene.  Most people would just gloss over the title “Gongylonema pulchrum Infection in a Resident of Williamsburg, Virginia, Verified by Genetic Analysis” without reading it at all, but those people would be missing out on a fascinating story.

Dr. Jonathan Allen felt something on the inside of his cheek one morning, and to his surprise it seemed that it moved under the skin back further into his mouth. Over the course of several months, it moved around in his mouth, until one day he was able to extract it with a very fine pair of forceps. He then transported it to the lab, determined the genetic identity of the worm by polymerase chain reaction and DNA sequencing, and then submitted a manuscript detailing the isolation and characterization of the worm.  A review of the medical literature indicated that Gongylonema infections of humans are rare, with less than 50 cases ever noted worldwide. The typical route of infection is via accidental food-borne ingestion of contaminated insects, which represent the intermediate host of the nematode. Generally eggs are passed in the feces of an infected mammalian host, where they are taken up by insects.  Fortunately in the case of Dr. Allen’s case, infection by his parasite was truly an end stage infection and the life cycle of the parasite was ended with his make shift surgical treatment.

Dr. Allen’s story related a sense of frustration in getting himself diagnosed. After being referred to an oral surgeon by his primary care physician at his initial complaint, the surgeon didn’t believe his self-diagnosis even after physical exam.  This is poor medicine, particularly in light of this summary from another case study from the journal Clinical Infectious Diseases:

Clinicians, other health care providers, and microbiologists alike need to be alert to the possibility of infection with Gongylonema species. The characteristic clinical finding of a wormlike object migrating in the mouth area, including the buccal mucosa, gums, lips, or palate, should be a clear signal for consideration of Gongylonema infection in the differential diagnosis.

Don’t wash raw chicken in the kitchen

“I always give my bird a generous butter massage before I put it in the oven. Why? Because I think the chicken likes it — and, more important, I like to give it.”

We continue our extended series of dangers in the house and the things we eat, with this story from National Public Radio. Long time readers of BIO230 will recall that I am no fan of cleanliness in the kitchen, and quite frankly this report comes as absolutely no surprise to me. Julia Child (pictured here) was a strong advocate of washing out the chicken carcass prior to adding seasoning and popping it in the oven. We are all likely aware that proper cooking of poultry greatly reduces the risk of food-borne disease from the roast chicken. But what about the rest of the kitchen?

It turns out that the act of rinsing out things in the kitchen sink results in the dispersal of huge numbers of microorganisms from the sink. Organisms present on poultry such as Salmonella and Campylobacter can be spread from the sink over a large area, up to at least 3 feet away from the sink. Food safety researcher Jennifer Quinlan of Drexel University is currently promoting a public health campaign to educate consumers of the potential danger of aerosolized pathogens from washed poultry. Her advice? Just make sure that the bird is cooked to an internal temperature sufficient to eliminate food-borne pathogens, and skip the washing step. To illustrate the risks of washing that bird, they show the dispersal of pathogens with “Germ-O-Vision:”

Commenters! For #bonus, identify reports in the media, or in the published literature (for example, via Pubmed) about additional microbiological dangers in the house. I will reward your work with a bonus point in Blackboard, which will also enable you to submit your own blog summaries later in the term for additional bonus! Here are the rules: this only goes through Monday September 9th (1 week to play), you must have something different than what has appeared in the comment thread (no repeats,) and you must include a link to click. Please note, if you have never commented on this blog before, you will not see it appear immediately. I will release it from moderation as soon as I see the comment.

The swimming pool and feces connection

Olympic Swimming Pool Fast Lane Category:Outdo...

Olympic Swimming Pool Fast Lane Category:Outdoor_swimming_pools (Photo credit: Wikipedia)

A study conducted by Georgia state health officials, along with the Centers for Disease Control and Prevention, has noted the presence of a number of microbial markers of feces contamination in a number of Atlanta area public swimming pools. Public health officials used polymerase chain reaction-based detection methods to look for potential indicators of contamination in the filters used to clean public pools during the 2012 swimming season. The filters are used to remove physical contaminants, including microorganisms from the water, and as such will typically have a higher level of contamination  in comparison to the rest of the water. Because contaminants accumulate in the filters, they must be regularly backwashed by reversing the water flow periodically, in order to maintain their effectiveness. Waste materials discharged from the backwash should be collected and removed as waste, and should not reenter the pool water system.

Filter samples were collected during the summer, and pool chlorine was immediately inactivated by adding sodium thiosulfate. Standard sets of patron data (indoor vs outdoor pool, public vs private, mixed ages vs primarily adult swimmers, specific signage at the pool) were also collected with the water samples. DNA from any microorganisms present in the water was purified, and used as a template for quantitative PCR using primers for specific microorganisms. Escherichia coli and Pseudomonas aeruginosa were detected in approximately 60% of the water samples. P. aeruginosa contamination was presumed to have occurred from the presence of environmental influx (either dirt or pool fill water; the organism is ubiquitously distributed), however E. coli contamination was used as an indicator of potential fecal contamination of the pool. Two other markers (Giardia intestinalis and Cryptosporidium sp.) of fecal contamination were only detected in a very small number of samples, and norovirus, adenovirus, and a pathogenic isolate of E. coli (E. coli O157:H7) were not detected in any samples. The proportion of samples positive for E. coli varied significantly between membership/club pools and public pools, but this figure did not vary significantly for P. aeruginosa between the two types of pools.

As is the norm with these types of studies, the CDC presents some “best practices” recommendations for individuals wanting to avoid recreational water illnesses (RWI). The risk for RWI rises dramatically if swimmers introduce feces via diarrhea; it is estimated that one swimmer can release up to 108 Cryptosporidium oocysts into the water, a number sufficient to cause disease if a mouthful of water is ingested. The CDC recommends that feces and urine be kept out of pool water, and offers these concrete steps to do so:

  • Don’t swim when you have diarrhea.
  • Shower with soap before you start swimming.
  • Take a rinse shower before you get back into the water.
  • Take bathroom breaks every 60 minutes.
  • Wash your hands after using the toilet or changing diapers.

Good bacteria helps bad breath

Marissa Weinfeld (3 PM Micro) found this article about halitosis and the oral microbiota. Her advice? Add more bacteria. Long time readers of BIO230 may recall my take on this topic from March 2011 (sorry Marissa–All That Has Happened Before Will Happen Again.)

Most people occasionally have bad breath however; about 25 percent of people have chronic bad breath.  Researches have discovered that the gas emitting bacteria on the tongue and below the gum line are responsible for the bad breath but have had a difficult time determining how to get rid of these bacteria responsible for the odor. Solutions to bad breath including mouthwash, brushing and flossing after meals may cause temporary relief but can also cause unpleasant side effects. Evidence from recent research has found that it is more effective to nurture helpful bacteria in the mouth rather than destroying the offending germs and their by-products.

Hydrogen sulfide and methyl mercaptan are found in higher levels in breath of bad breath individuals. These as well as other compounds are waste products released by the bacteria eating particles of food and tissue in our mouth. Gram-negative bacteria that live below the gum line and on the tongue produce more of the bad odors in breath. Mel Rosenberg a microbiology professor at Tel Aviv University and his colleague Nir Sterer recently found that some strains of gram-positive bacteria secrete an enzyme that clips sugar molecules off the proteins found in food, which makes those proteins more digestible for nearby gram-negative organisms. When gram-negatives digest proteins the more odors are emitted.

Current treatments that are said to improve oral ecology are found to make problems worse. A chlorhexidinse rinse was found to temporarily change the taste of food and was also found to cause a tingling or burning sensation on the tongue after a week of use on some users. Another find was that rinses with alcohol could dry out the mouth adding to the odors causing bad breath. It can also wipe out too many of the mouths normal bacteria allowing opportunistic species responsible for gum disease and other infections.

A researcher Rosenberg, developed a two-phase oil-and-water rinse that temporarily reduces bad breath by soaking up some of the oral debris and microbes that tooth brushing, flossing and tongue scraping miss.  Other researchers found that Streptococcus salivarius K12 can fight bad breath. In a study volunteers gargled with chlorhexidine mouthwash and sucked on lozenges laced with K12. A week to two weeks later they had much better breath. At U.C.L.A. a researcher is working mouthwash that contains peptide, which is tailored to selectively kill S.mutans, the bacterium that causes tooth decay. Using this in moderation may help bad breath. Research continues to find the cure for bad breath but for now the best solution seems to be good bacteria.

New Way to Treat Bed Bugs

Bed Bugs!

Bed Bugs!

Sandra Malinowski found this article regarding an insect vector, and the microbial flora they carry. Here is Sandra’s summary:

Many of us have said or heard “don’t let the bed bugs bite” before getting ready to go to sleep, I know my grandma always said that to me before bed.  What we don’t realize is that bed bugs are actually a real parasite.  These bed bugs are scientifically known as Climex lectularis and are small bloodsucking arthropods that can fit into any small cracks or crevices in our homes.  Most people don’t have issues with them throughout their lives but if they do they cause great grief trying to eliminate them.  They are most common in places where there are a lot of people and cleanliness is not the greatest, like dormitories, military barracks, and hotels, although they are not confined to just these places.  I remember seeing a television show where a camp was infested with bed bugs and they spend three years trying to get rid of them while almost going bankrupt because of them.  Bedbugs cause red itchy spots on its victims, which makes this hard to diagnose because they are similar to other insect bites and bed bugs are hard to see.

As it turns out an article on Science Daily discusses how Cincinnati has been experiencing real problems with bed bugs for several years.  They are one of the top bed-bug infested cities by pest control companies such as Terminex and Orkin, which has become a great trouble for them because bed bugs have posed increasing resistant to many insecticides.  The Cincinnati health department decided that they needed to organize a bed bug strategic plan to reduce the infestation wreaking havoc on the city.   Regina Baucom, and assistant professor of biological sciences at the University of Cincinnati decided to do something about these pests.  She started studying the DNA of local bed bug populations and found a way to better eliminate these resilient insects.  She saw the insect’s resistance to insecticides and pest control and realized that she needed to find an alternative way to eliminate these organisms.  In order to better understand these local bed bugs Baucom and her team performed a genetic analysis on 31 different bed bugs within 8 different residencies in Cincinnati which helped her to analyze other microbes present within the bed bug’s environment.

Baucom and her team discovered that there were two different bacterial types present in 97 percent of the microbial communities.  These included Wolbachia and an unnamed gamma proteobacteria.  The proteobacteria is not known much about but probably aids the bed bugs in growth somehow due to its presence.  More importantly the Wolbachia is a nutritional mutualist and helps the bed bugs with reproduction and growth.  By isolating these bacterium Baucom could then target these organisms in the pest control to greatly reduce the number of bed bugs due to the important role that they play in the health of a bed bug.  Since bed bugs are so hard to kill and pose a great nuisance for humans Baucom intuitively found a better way to decrease these organisms by not directly killing them but indirectly by eliminating factors that were aiding in their survival.  This was very helpful in the search for a better way to eliminate bed bugs, especially since they can pose a threat to a person’s psychological health and trigger allergic reactions.  Bedtime shouldn’t be a time to worry about creatures biting us, but a relief period.  Think of that next time someone tells you “not to let the bed bugs bite”, because it’s a real threat.

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