Alcohol-resistant bacteria Over recent years, researchers have noted a steady rise in the number of serious infections caused by one particular drug-resistant bacterium — Enterococcus faecium. Despite the wide use of alcohol-based disinfectants, E. faecium is now a leading cause of hospital-acquired infections.
A laboratory study looked at the penetration of alcohol into groups of microorganisms in the mouth and its effect on killing microbes. Alcohol concentrations lower than 40% were found to be significantly weaker in affecting bacterial growth. Alcohol with a 10% concentration had almost no effect.
Acinetobacter baumannii is a gram negative bacteria commonly found in the hospital specifically in equipment such as ventilators (Shirin 2018). They can live for a long period of time on environmental surfaces if not cleaned properly with alcohol. It is easily spread through human contact or surface contact.
High concentrations of ethanol are bactericidal; however, bacteria can grow in the presence of low concentrations of ethanol (21, 22).
They tested the bacteria against whiskey, vodka, different types of mixers and various environmental conditions. Bacteria continued to thrive in all of the samples except one: you guessed it, the whiskey. Whiskey was the only drink that completely eliminated all traces of the bacteria.
Generally Gram-positive bacteria will not grow in beer owing to the hop content; however, many strains of Lactobacillus spp. and Pediococcus spp. have obtained the horA gene that helps deal with this problem 26, 89-95.
These authors found that, when a wine was bottled unfiltered, Saccharomyces yeast and acetic acid bacteria tended to die readily, whereas non-Saccharomyces yeast and lactic acid bacteria tended to survive in the wine for a long time.
E. coli can metabolize ethanol, oxidizing it to acetate (7), but exposure to high concentrations of ethanol impedes its growth.
Alcohol concentrations lower than 40% were found to be significantly weaker in affecting bacterial growth. Alcohol with a 10% concentration had almost no effect. The exposure time of alcohol was also important.
Not only can certain bacteria survive in alcohol, but some actually thrive on it. Acetobacter, for example, consumes alcohol, digests it and produces vinegar as a byproduct. That said, when the alcohol becomes concentrated enough it becomes to hygroscopic that it dehydrates the bacteria and inactivates them.
Gram-positive bacteria (e.g. Staphylococcus) have a thicker peptidoglycan cell wall and are less vulnerable to alcohol-based sanitizers, but can still be killed by these sanitizers.
The gram-positive organisms Staphylococcus aureus and Streptococcus pyogenes were slightly more resistant, being killed in 10 seconds by ethyl alcohol concentrations of 60%–95%.
Alcohols have shown great in vitro efficacy against Gram-positive bacteria, Gram-negative bacteria (including multidrug-resistant pathogens such as MRSA and VRE) and fungi.
If the sugar content is high enough and oxygen is introduced to the environment, a rum could potentially grow a bacteria culture on its surface. This would be more likely if the rum is left uncorked, or corked and uncorked a lot.
One-off and regular drinking can interfere with the functions of the stomach in a number of ways. Alcohol can affect stomach acid production. This can reduce the stomach's ability to destroy bacteria that enter the stomach, which can allow potentially harmful bacteria to enter the upper small intestine.
At 30-40 % ABV, liquor isn't a good habitat for bacteria. Without opening it there will be virtually no oxidation. Only when you open bottles will it begin to deteriorate if improperly stored. Unlike wines or other liquors, such as cream liqueurs, tequila will not go bad.
That means the bacteria were able to survive for longer periods of time after being doused with alcohol. The researchers used different strengths of alcohol concentrations to combat the bacteria, starting with 23 percent. Eventually, at a 70-percent alcohol mixture, the bacteria were conquered.
Alcohol and other antiseptics may be ineffective against spores in part because they are unable to access sites of action in the spore core [18,19].
70% isopropyl alcohol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria, fungi and many viruses, but is ineffective against bacterial spores (CDC, 2020).
The gram-negative E. coli O157:H7 and Salmonella Typhimurium were unable to grow in mid- and full-strength beer, although these bacteria could survive for periods exceeding 30 days in mid- strength beer. These pathogens grew rapidly in alcohol-free beer; however, lowering the pH of the beer prevented growth.
Minuscule amounts of ethanol can at least double the life span of a tiny worm used as a model for aging studies, biochemists report. "This finding floored us; it's shocking" said the senior author of the study.
In theory a high enough alcohol concentration with sufficient exposure to gut or oral tissue could kill bacteria but will in all likelihood also damage the gut lining. It's not advised alcohol be used as a regular disinfectant to treat tummy bugs or throat infections.
According to the United States Department of Agriculture's (USDA) microbiologists, alcoholic beverages such as spirits, wine, or beer don't kill bacteria. Marinating meat and poultry in these liquids helps tenderize and flavor the meat but does not make it safe.
The MIC values show the minimal concentration of wine needed to kill E. coli, while the results of the agar-well diffusion method show the ability of the wine to inhibit the growth of inoculated bacteria. The wines demonstrated antimicrobial effect against both E. coli strains.
Wine, particularly white wine, was found to help kill E. coli and salmonella in recent experiments by food scientists at Oregon State University in Corvalis. The combination of alcohol and acidity prevented the bacteria from reproducing, prompting the researchers to work on developing a wine-based disinfectant.