Molecular structure of the antibiotic enroflaxcin.

A brief letter was recently published in Nature that identifies a bacteria that may confer resistance to C. difficile. In addition, they discovered how three commonly prescribed antibiotics alter a patient's risk for C. diff.

The researchers treated mice with 3 different antibiotics, enrofloxacin, ampicillin, and clindamycin. While the overall microbiome bacterial density was unchanged for each antibiotic, each one altered C. diff susceptibility differently: enrofloxacin did not increase likelihood of getting infected, ampicillin induced transient susceptibility, and clindamycin greatly increased long-term chances of getting infected.

The researchers then identified 11 bacteria that were associated with C. diff resistance. They tested one of these bacteria, Clostridium scindens, on humans taking antibiotics that either already had C. diff infections or were susceptible for infection. They discovered that the probiotic conferred substantial resistance to infection. Interestingly, this probiotic also led to weight loss.

The researchers then studied how this bacteria could be preventing C. diff infection. They discovered that this particular bacteria had a rare ability to break down bile into secondary structures, called secondary bile acids. They tested these secondary bile acids against C. diff and they inhibited C. diff growth.

These results, taken collectively, may be immensely important in treating d. Diff. Specific types of antibiotics that are known to not increase infection risk, along with probiotics like C. scindens could be combined into new therapies. This could be important in treating this disease without more rudimentary approaches like fecal microbiota transfers (FMTs).