A new study suggests that repeated or prolonged courses of antibiotic drugs has negative consequences for the essential 'good' bacteria that reside in our guts.
Researchers at Standford University in the US have found that the use of antibiotics may have a larger and more prolonged impact on the resident populations of 'good' or 'friendly' gut bacteria then has been suspected.
Antibiotics have for a long time been seen as the "magic bullet" to infectious disease, and to a large extent this has been close to the truth. Before Fleming discovered penicillin infectious diseases were rampant so the development of readily available antiobiotic drugs meant an easy fix for a number of serious diseases as well as minor but troublesome local infections.
This for a long time however has led to what some may consider an unhealthy relationship with antibiotics where they are dished out to all-comers with little thought for potential consequences.
Recently with the rise of antibiotic superbugs such as MRSA, thought to be the result of overuse of antibiotics, things have begun to change. Antibiotics are beginning to be treated with more respect and used more wisely and with more restraint. Doctors have been educated on the risks and this information has been passed on to patients with waiting rooms adorned with posters presenting the facts about the drugs. Doctors have often been pressured into prescribing antibiotics by demanding patients even when the problem is likely a viral infection to against which they are ineffective.
Antibiotic-resistant superbugs are not the only problem associated with antibiotic use however; they also kill the good bacteria in our guts which are vital to not just gut health but that of the entire body. This is what the current study by Stanford researchers has been looking at.
The research team looked at the effects of the widely-used antibiotic ciprofloxacin (commonly referred to as simply 'cipro'). This drug is prescribed for a number of bacterial infections and related conditions, including urinary tract infections, respiratory infections, some STDs, and infections of soft tissue. Scientitsts had assumed that ciprofloxacin caused only modest harm to good bacteria in the gut and other mucous membranes of the body e.g. the vagina.
During the study, lead researcher Dr. David Relman and colleagues catalogued bacteria in the feaces of volunteers being treated with ciprofloxacin; identifying more than 5,600 different bacterial species and strains.
They found however that while the patients were taking the antibiotic, the overall abundance of about 30 percent of the bacterial species and strains was significantly affected.
An interesting finding was that the effects of the antibiotic on gut bacteria populations varied greatly between individuals, with two volunteers showing a particularly dramatic reduction in bacterial diversity. The study also found that once antibiotic treatment was completed, it took up to four weeks for most strains of gut bacteria to return to pre-treatment levels.
It's possible that this period of recovery could give pathogenic bacteria such as Clostridium difficile and other organisms such as yeast the chance to proliferate and cause disease.
It has been thought that populations of beneficial bacteria returned to pre-treatment levels very rapidly after antibiotic cessation but this study demonstrates this may not be the case and that some individuals are particularly susceptible to antibiotic disturbance of healthy gut bacteria.
Good bacteria are important for many aspects of health and are involved in the digestive process (producing vitamins B and K and beneficial short-chain fatty acids), promoting a healthy immune system (by preventing infection by pathogenic bacteria and stimulating antibody production), and they may even lower cholesterol by making sure bile is broken down efficiently and cholesterol removed from the body in the faeces.
The researchers conclude that while the study results reveal aspects of resiliency in gut bacteria, they also suggest that antibiotic treatment may have long-lasting effects on overall health that could go unnoticed.