Breaking Protective Barriers: We don't tend to think of bacteria exhibiting behavior, but in a sense nearly all of them do, as the following explains.
Single-celled organisms generally exhibit two distinct modes of behavior. The first is the familiar free floating, or planktonic, form in which single cells float or swim independently in some liquid medium. The second is an attached state in which cells are closely packed and firmly attached to each other and usually form a solid surface. A change in behavior is triggered by many factors, including quorum sensing, as well as other mechanisms that vary between species. When a cell switches modes, it undergoes a phenotypic shift in behavior in which large suites of genes are up- and down-regulated.
Examples of microorganisms exhibiting that second state include the plaque on our teeth and the coating that develops on contact lenses. Nowadays, the proper term is biofilm.
Many types of bacteria, such as MRSA, exist in colonies that adhere to the surfaces of materials. The colonies often form coatings, known as biofilms, which protect them from antiseptics, disinfectants, and antibiotics.
Time out for some more definitions.
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. They should generally be distinguished from antibiotics that destroy bacteria within the body, and from disinfectants, which destroy microorganisms found on non-living objects. Some antiseptics are true germicides, capable of destroying microbes (bacteriocidal), whilst others are bacteriostatic and only prevent or inhibit their growth.
Salts in liquid form are showing some promise when it comes to killing bacteria which have protected themselves with biofilms. Returning to the second link...
Earle said: "We have shown that when pitted against the ionic liquids we developed and tested, biofilms offer little or no protection to MRSA, or to seven other infectious microorganisms."
Ionic liquids, just like the table salt sprinkled on food, are salts. They consist entirely of ions - electrically-charged atoms or groups of atoms. Unlike table salt, however, which has to be heated to over 800 C [1472 F] to become a liquid, the ionic liquid antibiofilm agents remain liquid at the ambient temperatures found in hospitals.
One of the attractions of ionic liquids is the opportunity to tailor their physical, chemical, and biological properties by building specific features into the chemical structures of the positively-charged ions (the cations), and/or the negatively-charged ions (the anions).
Earle said: "Our goal is to design ionic liquids with the lowest possible toxicity to humans while wiping out colonies of bacteria that cause hospital acquired infections."
Salting kills slugs via a different mechanism.
Getting Stronger: Dilution isn't always the solution.
Biocides are used in disinfectants and antiseptics to kill microbes. They are commonly used in cleaning hospitals and home environments, sterilizing medical equipment and decontaminating skin before surgery. At the correct strength, biocides kill bacteria and other microbes. However, if lower levels are used the bacteria can survive and become resistant to treatment.
That's one of the alarming things about various antibiotics, biocides, etc. being found in low levels in the environment.
"Bacteria like Staphylococcus aureus make proteins that pump many different toxic chemicals out of the cell to interfere with their antibacterial effects," said Dr Glenn Kaatz from the Department of Veterans Affairs Medical Center in Detroit, USA. "These efflux pumps can remove antibiotics from the cell and have been shown to make bacteria resistant to those drugs. We wanted to find out if exposure to biocides could also make bacteria resistant to being killed by the action of efflux pumps."
The researchers exposed S. aureus taken from the blood of patients to low concentrations of several biocides and dyes, which are also used frequently in hospitals. They looked at the effect of exposure on the bacteria and found that mutants that make more efflux pumps than normal were produced.
"We found that exposure to low concentrations of a variety of biocides and dyes resulted in the appearance of resistant mutants," said Dr Kaatz. "The number of efflux pumps in the bacteria increased. Because the efflux pumps can also rid the cell of some antibiotics, pathogenic bacteria with more pumps are a threat to patients as they could be more resistant to treatment."
Note the MRSA stands for methicillin-resistant Staphylococcus aureus.
Canned Heat: People who are desperate for alcohol will drink some weird stuff.
The term "non-beverage alcohols" refers to manufactured liquids that contain alcohol but are not intended for consumption, such as medicinal tinctures, aftershave, alcohol-based anti-freeze, antiseptics, and eau-de-colognes. Drinking these products is very hazardous to one's health.
According to the Organization for Economic Co-Operation and Development (OECD), the alcohol consumption per capita in Russia is almost 4 gallons a year. In the U.S., it's 2.2 gallons per year. Switching links...
The Government’s strict licensing system, introduced under pressure from President Putin, prompted concern that poorer people were risking their lives by drinking cleaning fluids as vodka prices rose to pay for the new licences.
Recent research indicates that 7 percent of working-age Russian men living in the Ural Mountains drank non-beverage alcohol within the previous year. Returning to the earlier link...
Leon and his colleagues surveyed 17 cities--representative of a wide range of city types--in the Russian Federation, excluding the Far East, during the first half of 2007. Fieldworkers visited pharmacies and other types of retail outlets in order to purchases samples of various kinds of non-beverage alcohols. Guidelines for purchases included 10 - 15 roubles per bottle, with an alcohol concentration of at least 60 percent by volume.
"We found that non-beverage alcohols were widely available throughout the 17 Russian cities we surveyed," said Leon. "This empirically provides a very important basis for arguing that further tighter regulation of these substances is necessary. On the positive side, and somewhat contrary to our expectations, it appears that the 2006 federal regulations have resulted in a decline in the availability of eau-de-colognes, but not medicinal tinctures." Medicinal tinctures, sold almost exclusively in pharmacies, were particularly common – with an average concentration of 78 percent alcohol by volume.
"These concentrations are very high compared to spirits," noted Leon, "and are often prominently displayed on labels and packaging as they attract people to buy them, knowing that they will get a lot of alcohol for the cheap price they pay. However, it should be noted that it is not known what proportion of people drink these substances straight from the bottle. An appreciable proportion probably dilute the products with water and hence have a large volume to drink, much like buying concentrated fruit juice that needs dilution to drink."
Methanol is added to sterno to denature it--to make it undrinkable. In sufficient quantity, methanol is toxic...it can blind and/or kill.
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