Malassezia spp. microorganisms also inhabit skin during acne

Most people experience acne at some point in their life, and the AMI has discussed the microbiome’s role in this skin condition many times in our blog and podcasts.  Cutaneous inflammation is observed in people with acne, as well as increased amounts of the Propionibacterium acnes (P. acnes) bacteria.  However, a recent study conducted by dermatologists in Japan quantitatively examined microbiota in follicular skin contents, and providing more evidence that Malassezia spp. fungi may also be present during facial acne episodes in addition to P. acnes. 

15 untreated acne patients were selected for the study, all of whom had not received previous treatments with topical and/or steroid/antibiotic regiments.  A comedo extractor was used to collect follicular contents from inflammatory acne lesions from the cheek and foreheads of patients, and these samples were subject to DNA extraction and subsequent PCR analysis to characterize microbiota species.  Staphylococcus and Propionibacterium were found in follicular contents, but interestingly Malassezia spp. fungi were also observed.  Furthermore, Malassezia spp. fungi in follicular contents were correlated with inflammatory acne and with content on the skin surface, while Staphylococcus and Propionibacterium were not. 

These findings suggest that Propionibacterium acnes may not be the only microbiota skin residents related to acne.  While this was not the first paper to point to Malassezia spp. fungi as implicated in acne, these researchers addressed prior experimental method concerns and utilized advanced quantitation methods such as PCR rather than culture-methods.

Proton pump inhibitors affect the microbiome

Proton pump inhibitors (PPI) are used to reduce gastric acid production in individuals’ guts and are prescribed to treat ulcers, gastroesophogeal reflux disease (GERD), and other conditions associated with acid production. It is one of the most commonly used drugs in the world. We know (and have written about) that PPIs are associated with increased intestinal infections, specifically Clostridium difficile, and the gut microbiome plays an important role in infections of the intestine. A recent study looked at the influence that PPIs had on the gut microbiome.

The team of researchers studied the gut microbiome of 1815 individuals. They looked at PPI users vs non-users. Of those sampled, 215 of them were taking a PPI at the time that a sample was taken. It was found that those taking the PPIs had lower microbial diversity compared to those not taking PPIs. They also found that bacteria usually found in the mouth was over-represented in the fecal samples of those taking PPIs, including those in the Rothia genus. They also observed an increase in Enterococcus, Streptococcus, Staphylococcus, and Escherichia coli, a potentially pathogenic bacterium.

PPI usage effects are more prominent than those of most other drugs, including antibiotics. The results of this study are consistent with a less healthy microbiome and allow us to better understand why PPIs may lead to an increase of susceptibility to intestinal infections like C. diff.

Operating room bacteria colonize infants’ guts after C-sections

Newborns are a great study subject in the field of microbiology, because scientists are still discovering how the microbiome develops and what factors affect it. In human infants, it has been proven that vaginal birth exposes infants to bacteria that are different from those received by the mother through C-section. Babies born by vaginal delivery have gut bacteria correlated with vaginal bacteria, while babies born by C-section have gut bacteria correlated with human skin bacteria. For babies born by C-section, the sources of the human skin microbes that are acquired are still unknown.  In a study published by Microbiome, a group of scientists tested the hypothesis that the operating room environment contains human skin bacteria that could be seeding the gut microbiome of C-section born babies.

To test their hypothesis, the researchers collected samples from 11 sites in four operating rooms from three hospitals in New York City, NY and San Juan, PR. Of the 44 operating room samples that were collected, 68% of the samples contained a sufficient number of bacterial DNA samples for sequence analysis. After analyzing the bacteria collected, it was found that all samples contained human skin bacteria, with Staphylococcus and Corynebacterium being the greatest in quantity. Lamps on the operating bed and baby crib showed higher abundances of these bacteria relative to the other sampling sites. The scientists confirmed that the samples collected were more similar to human skin microbiota than other body sites, by comparing the samples to oral, fecal, and vaginal database samples.       

Even though operating rooms are supposed to be spotlessly clean and germ-free, this study shows that there are still dust particles containing human skin, and therefore human skin microbiota, samples. These samples could be from people moving in and out of the operating room during a C-section, or it could come from the people cleaning the OR. Either way, the human skin bacteria in the operating room most-likely are what influences the infant’s developing gut microbiome.