Antibiotics as Major Disruptors of Gut Microbiota

Drug administration may cause disturbance of the gut microbiota. It is believed that antibiotics can affect the intestinal microfloral balance and allow naturally opportunistic organisms to grow and multiply. Antibiotic therapy produces some side effects in the host, including disturbance of the metabolism and absorption of vitamins, alteration of susceptibility to infections and overgrowth of yeast and/or Clostridium difficile.

Azithromycin (deoxo-azamethyl-homo-erythromycin, AZM) is the most widely used synthetic analogue having antimicrobiological properties. It is active against a wide number of pathogens including Streptococci, Staphylococcus aureus, Propioni­bacterium acnes, Listeria monocytogenes, Haemophilus influenzae, Neisseria gonorrhoeae, Mycobacterium avium, and Chlamydia trachomatis. AZM belongs to the macrolide antibiot­ics and is currently widely used in the treatment of cystic fibrosis patients. It is currently recommended as chronic therapy for cystic fibrosis patients infected with Pseu­domonas aeruginosa. Long-term administration of AZM helps to reduce or stabilize clinical symptoms of airway inflammation in patients chronically infected with P. aeruginosa. Some side effects are associated with this macrolide therapy. One study has reported a significant increase in mild adverse effects (wheezing, diarrhea and nausea) in patients receiv­ing azithromycin.