The bacterial burden of worn face masks-observational research and literature review.

Introduction: Facemasks were widely mandated during the recent SARS-CoV-2 pandemic. Especially the use by the general population is associated with a higher risk of improper handling of the mask and contamination and potential adverse microbiological consequences.

Methods: We investigated and quantified bacterial accumulation in facemasks used by the general population, using 16S rRNA (Sanger Sequencing), culture and biochemical analysis along with Rose Bengal staining.

Recombination Events in Putative Tail Fibre Gene in Phages Infecting and Their Phylogenetic Consequences.

Recombination is the main driver of bacteriophage evolution. It may serve as a tool for extending the phage host spectrum, which is significant not only for phages' ecology but also for their utilisation as therapeutic agents of bacterial infections. The aim of this study was to detect the recombination events in the genomes of phages infecting , and present their impact on phylogenetic relations within this phage group.

Scientific and Regulatory Policy Committee Best Practices: Documentation of Sexual Maturity by Microscopic Evaluation in Nonclinical Safety Studies.

The sexual maturity status of animals in nonclinical safety studies can have a significant impact on the microscopic assessment of the reproductive system, the interpretation of potential test article-related findings, and ultimately the assessment of potential risk to humans. However, the assessment and documentation of sexual maturity for animals in nonclinical safety studies is not conducted in a consistent manner across the pharmaceutical and chemical industries. The Scientific and Regulatory Policy Committee of the Society of Toxicologic Pathology convened an international working group of pathologists and nonclinical safety scientists with expertise in the reproductive system, pathology nomenclature, and Standard for Exchange of Nonclinical Data requirements.

Developmental milestones in neonatal and juvenile C57Bl/6 mouse - Indications for the design of juvenile toxicity studies.

There is a growing demand for wild type mice and mouse models of disease that may be more representative of human conditions but there is little information on neonatal and juvenile mouse anatomy. This project produces sound and comprehensive histology background data on the developing neonatal mouse at different time points from Day 0 until Day 28. The work describes optimal methods for tissue harvesting, fixation and processing from the neonatal and juvenile mice which can be used in routine toxicology studies.