That the use of broad-spectrum antibiotics long period of time can lead to severe secondary bacterial infections because the bacteria destroys the “good bacteria” in the gut, which are an essential part of the immune system has long been a problem of the use of antibiotics.
New researcher from the University of Pennsylvania School of Medicine may have found one of the disease fighting mechanisms of healthy gut flora and confirms the importance of a healthy gut in fighting disease.
The investigators show that “good” bacteria in the gut keep the immune system primed to more effectively fight infection from invading pathogenic bacteria. Altering the intricate dynamic between resident and foreign bacteria – via antibiotics, for example – compromises an animal’s immune response, specifically, the function of white blood cells called neutrophils.
The implication of these initial findings in animals, he says, is that prolonged antibiotic use in humans may effectively throttle down the immune system, such that it is no longer at peak efficiency.
Senior author Jeffrey Weiser, MD, professor of Microbiology and Pediatrics, likens these findings to starting a car: It’s much easier to start moving if a car is idling than if its engine is cold. Similarly, if the immune system is already warmed up, it can better cope with pathogenic invaders.
“Neutrophils are being primed by innate bacterial signals, so they are ready to go if a microbe invades the body,” Weiser explains. “They are sort of ‘idling’, and the baseline system is already turned on.”
The findings are published in the journal Nature Medicine.
“One of the complications of antibiotic therapy is secondary infection,” Weiser explains. “This is a huge problem in hospitals, but there hasn’t been a mechanistic understanding of how that occurs. We suggest that if the immune system is on idle, and you treat someone with broad-spectrum antibiotics, then you turn the system off. The system is deprimed and will be less efficient at responding quickly to new infections.”
The findings also provide a potential explanation for the anecdotal benefits of probiotic therapies because keeping your immune system primed by eating foods enhanced with “good” bacteria may help counteract the negative effects of sickness and antibiotics.
Researchers have for many years understood that most bacteria in the body are not “bad.” In fact, humans (and mice) have a symbiotic relationship with their resident microbes that significantly impacts, among other things, metabolism and weight homeostasis. As shown in this study, microbes also affect the innate immune response.