January 29, 2018
Living With The Bugs
By Michael D. Shaw
(“Bugs” here refers to pathogenic microorganisms.) This column has run several articles on infection control issues, including endoscope reprocessing; outbreaks of MRSA; and continuing problems at VA hospitals. But, all those stories took place in hospitals. This time, we examine encounters with pathogens faced by all of us, hospitalized or not.
Patricia Salber MD, MBA provides a wonderful summary on her blog. We have already been warned about how this could be a bad flu season, based on reports from Australia, where their winter coincides with our past summer. It doesn’t help that this year’s flu vaccine is projected to be only 10-33 percent effective, as compared to the usual 40-60 percent efficacy.
Still, as Dr. Salber reminds us, “It is important to understand that even when the match [of the flu vaccine to the actual strains of circulating viruses] is poor, the vaccine has been shown to reduce the risk of hospitalization and death from influenza.”
Here are a few other key points:
1. You probably have the flu if your symptoms include a cough, fever, headache, sore throat, muscle aches, and chills. According to a large study, having both a cough and fever was 79% predictive of really having the flu.
2. The flu hardly ever causes an upset stomach. “Stomach flu” is actually a non-influenza viral gastroenteritis.
3. Although most people who get the flu feel better in 1-2 weeks, it is still the most frequent cause of death from a vaccine-preventable disease in the United States. Deaths will occur due to secondary infections; exacerbation of already existing conditions; or a cytokine storm.
Treatment of the flu generally involves alleviating symptoms (pain and fever relief), pushing fluids, and getting plenty of rest. Antivirals can be of a small benefit if started within two days of the onset of symptoms.
Escherichia coli, a gram-negative bacterium inhabiting the stomach and intestines, was discovered in 1885 by German bacteriologist Theodor Escherich, and was named in his honor many years later. More than 700 serotypes of the species have been identified, the majority of which are harmless. However, some strains produce toxins which can cause symptoms ranging from mild diarrhea to kidney damage and death. The most notorious baddie is E. coli O157:H7.
According to a study published in 2011, an estimated 93,094 illnesses are due to domestically acquired E. coli O157:H7 each year in the United States.
As that monograph explains:
“E. coli O157:H7’s ability to induce injury in humans is a result of its ability to produce numerous virulence factors–most notably, Shiga-like toxins [so-named because of the resemblance to toxins produced by Shigella dysenteries]. Shiga toxin is one of the most potent toxins known. In addition to Shiga toxins, E. coli O157:H7 produces numerous other putative virulence factors including proteins, which aid in the attachment and colonization of the bacteria in the intestinal wall and that can lyse red blood cells to liberate iron that helps support E. coli metabolism.”
If that were not bad enough, E. coli O157:H7 can harm with an absurdly small infectious dose–said to be as low as 20 organisms per gram of food. And, this little beastie is remarkably resilient, not to mention that it can be transmitted by person-to-person contact.
As to the source of these outbreaks, the article names foods of bovine origin as the most common cause, but then lists a disturbing variety of other foods, including produce, unpasteurized juices, yogurt, dried salami, mayonnaise, raw milk, game meats, sprouts, and raw cookie dough. Speaking of produce, currently in the news is an outbreak of E. coli O157:H7, linked to leafy greens. Consumer Reports got more specific, and recommended that consumers avoid romaine lettuce.
We conclude with some recommendations from the Minnesota Department of Health as to how you and your family can avoid E. coli infection. (Greater detail at linked page.)
Consumers can prevent E. coli contamination by:
- Avoiding unpasteurized beverages
- Being careful when dealing with animals
- Cooking and serving your food at the appropriate temperatures
- Keep ill children home from daycare and preschool
- Keeping your food preparation areas clean
- Serving irradiated hamburger
- Using caution when swimming
- Washing hands carefully