Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries.

Aim: To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach.

Materials And Methods: Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene.

Association of nine pathobionts with periodontitis in four South American and European countries.

Aim: Our aim was to compare the prevalence and load of nine pathobionts in subgingival samples of healthy individuals and periodontitis patients from four different countries.

Methods: Five hundred and seven subgingival biofilm samples were collected from healthy subjects and periodontitis patients in Belgium, Chile, Peru and Spain. The prevalence and load of and were measured by quantitative PCR.

Tetracycline and multidrug resistance in the oral microbiota: differences between healthy subjects and patients with periodontitis in Spain.

: Antibiotic resistance is widely found even among bacterial populations not having been exposed to selective pressure by antibiotics, such as tetracycline. In this study we analyzed the tetracycline-resistant subgingival microbiota of healthy subjects and of patients with periodontitis, comparing the prevalence of genes and their multidrug resistance profiles. : Samples from 259 volunteers were analyzed, obtaining 813 tetracycline-resistant isolates.

Resistance to β-lactams and distribution of β-lactam resistance genes in subgingival microbiota from Spanish patients with periodontitis.

Objectives: The aim of this study was to analyze the distribution of β-lactamase genes and the multidrug resistance profiles in β-lactam-resistant subgingival bacteria from patients with periodontitis.

Materials And Methods: Subgingival samples were obtained from 130 Spanish patients with generalized periodontitis stage III or IV. Samples were grown on agar plates with amoxicillin or cefotaxime and incubated in anaerobic and microaerophilic conditions.

Detection and expression analysis of (B) in .

Tetracycline resistance can be achieved through genes, which code for efflux pumps, ribosomal protection proteins and inactivation enzymes. Some of these genes have only been described in either Gram-positive or Gram-negative bacteria. This is the case of (B), which codes for an efflux pump and, so far, had only been found in Gram-negative bacteria.