Robust & Resilient Human Fecal Predominat Microbiota

The effects of A Short-Course Antibiotic Challenge

A valid question often posed by our customers is “how stable are the levels of predominant bacteria over time”? This question together with the question of the effect of a short-course antibiotic challenge was explored in study by French researchers published in the journal of clinical microbiology.

In view of determining appropriate and timely treatment, practitioners using the GI function profile frequently seek advice as to how likely the predominant bacteria levels on a given test result are going to fluctuate over time. Justifiably, practitioners want to ensure the results they are seeing are indicative of the patients’ normal balance of predominant bacteria and therefore it treated appropriately should result in a return to health for the patient.

In the study cited below, authors suggest that even when allowing for natural oscillations of dominant fecal flora, levels of predominant species should remain within 90% of similarity with the equilibrium state. This is due to the now widely accepted phenomenon of ‘colonization resistance’.

The question then arises as to the effect of antimicrobial therapy on predominant fecal microbiota. French researchers used 6 healthy volunteers and gave each 1.5 grams of amoxicillin orally for five days. Fecal samples were collected before antibiotic treatment and at set intervals until 60 days thereafter. Dominant species of microbiota were assessed in each sample using molecular techniques similar to those employed for the GI Function Profile.

Researchers found that dominant species of the human fecal microbiota were markedly modulated within 2 to 3 days of the antibiotic treatment. The dominant fecal microbiota tended to return to its initial profile within 60 days. Whilst the microbiota profile for five out of six volunteers came back to near initial composition with 60 days, in one subject significant modifications persisted for at least 2 months.

The authors suggested that the persistence of significant modifications in predominant microbiota in one of the six subjects may explain the occasional development of chronic disorders following antibiotic treatment.

This study is an example of how direct quantification of predominant fecal microbiota using molecular techniques can help determine precise effects of anti-microbial treatment of microbiota and the relevant need thereof. We encourage our clients to take the time to download the following study and review its findings.

http://www.pubmedcentral.nih.gov/picrender.fcgi?tool=pmcentrez&artid=1287787&blobtype=pdf