Fungal infection risks: How antibiotics affect the gut microbiota

 

A new finding from the University of Birmingham (U.K.) demonstrates how antibiotics can lead to fungal infection because of the disruption of the drugs to the gut's immune system, altering the microbial balance. The research relates to the hospital setting, with a focus on invasive candidiasis.

 

When patients are given antibiotics to prevent sepsis and other bacterial infections that spread quickly around hospitals (such as Clostiroides difficile), the effect of the antibiotics does not only affect the target organism leading to alterations to the normal microbiota of the gut.  Consequently this creates opportunities for fungal to occur.

 

In other words, a reduction in the number of gut bacteria as a result of antibiotic therapy reduces competition for space and leaves more room for fungi to multiply. The problem for medics is that the underlying factors causing these infections are not well understood.

 

It was also of concern that where antibiotics disrupt the immune system, then fungal infections become poorly controlled and where such fungal infections develop, gut bacteria, including the target pathogens of the antibiotics, are also less prone to the effects of the antibiotic; hence, the risk of bacterial infection also increases.

 

To demonstrate this, the scientists used mice treated with a broad-spectrum antibiotic cocktail. The rodents were next infected with Candida albicans. It was found that while infected mice had increased mortality, this was caused by infection in the intestine, rather than in the kidneys or other organs.

 

Following this, the researchers pinpointed what parts of the immune system were missing from the gut after antibiotic treatment. These components were next added back into the mice using immune-boosting drugs. This approach helped reduce the severity of the fungal infection.

 

A follow-up assessment of hospital records suggested that similar co-infections probably occur in humans.

 

The research adds to our understanding of how antibiotics can have additional effects on our bodies. This further underscores the importance of careful stewardship of available antibiotics.

 

The counter the risk of fungal infections, the researchers speculate that the use of immune-boosting drugs at the same time that antibiotics are administered could reduce the health risks from e complex fungal infections.

 

The findings appear in the journal Cell Host & Microbe, titled “Long-term antibiotic exposure promotes mortality after systemic fungal infection by driving lymphocyte dysfunction and systemic escape of commensal bacteria.”

 

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)