Stable isotope probing with O-water to investigate microbial growth and death in environmental samples.

Growth and mortality of microorganisms have been characterized through DNA stable isotope probing (SIP) with O-water in soils from a range of ecosystems. Conventional SIP has been improved by sequencing a marker gene in all fractions retrieved from an ultracentrifuge tube to produce taxon density curves, which allow estimating the atom percent isotope composition of each microbial taxon's genome. Very recent advances in SIP with O-water include expansion of the technique to aquatic samples, investigations of microbial turnover in soil, and the first use of O-water in RNA-SIP studies.

Impact of saline irrigation and topical corticosteroids on the postsurgical sinonasal microbiota.

Background: Topical treatments with nasal saline irrigation, topical steroid sprays, or corticosteroid rinses can improve sinonasal symptoms in chronic rhinosinusitis (CRS). However, the impact of these therapies on commensals (Corynebacterium) and on biofilm pathogens associated with CRS (Staphylococcus aureus and Pseudomonas) is not well characterized.

Methods: Paired nasal and sinus swabs were collected endoscopically from 28 controls and 14 CRS patients with nasal polyposis (CRSwNP) who had not received systemic antibiotics or corticosteroids in the previous 8 weeks.

Rapid differentiation between livestock-associated and livestock-independent Staphylococcus aureus CC398 clades.

Staphylococcus aureus clonal complex 398 (CC398) isolates cluster into two distinct phylogenetic clades based on single-nucleotide polymorphisms (SNPs) revealing a basal human clade and a more derived livestock clade. The scn and tet(M) genes are strongly associated with the human and the livestock clade, respectively, due to loss and acquisition of mobile genetic elements. We present canonical single-nucleotide polymorphism (canSNP) assays that differentiate the two major host-associated S.

Medical therapy reduces microbiota diversity and evenness in surgically recalcitrant chronic rhinosinusitis.

Background: Chronic rhinosinusitis (CRS) is a highly prevalent and heterogeneous condition frequently treated with antibiotics and corticosteroid therapy. However, the effect of medical therapy on sinus microbiota remains unknown.

Methods: We enrolled CRS patients (n = 6) with patent maxillary antrostomies and active mucosal inflammation, who had not received antibiotics or corticosteroids in the previous 8 weeks.