Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Factors Determining the Uptake of Influenza Vaccination among Children with Chronic Conditions

Background: Studies report that the influenza vaccination uptake rate among children with chronic conditions is alarmingly low. In Hong Kong, there has been no study examining parental decision making about influenza vaccination for children with chronic conditions, thereby limiting the knowledge base to inform the development of specific strategies to improve influenza vaccination rates. The aim of this study was to identify factors determining the uptake of influenza vaccination among children with chronic conditions. Methods: We conducted a cross-sectional survey of 623 parents with children having a chronic condition recruited from pediatric wards and specialty outpatient departments of 2 acute hospitals. A questionnaire developed by Daley et al based on the Health Belief Model was used to examine parents' beliefs and attitudes toward influenza and vaccination. Results: The parents' and their children's mean age were 40.1 ± 8.1 and 8.0 ± 4.5 years, respectively. Among the children, the most prevalent chronic conditions were asthma, chronic respiratory disease and cardiomyopathy. One-third (33%) of the children had influenza vaccination in the past 12 months. More than one-third (39%) of parents intended to vaccinate their children against influenza in the coming influenza season. A multivariable logistic regression analysis revealed that all subscale scores except perceived severity and knowledge about influenza were independently significantly associated with uptake. Conclusions: The findings indicate that parents of children with chronic conditions lack awareness of the risks of influenza and have insufficient understanding about the benefits of vaccination. These findings could inform the development of interventions to promote vaccination uptake among children with chronic conditions

The Burden and Benefits of Knowledge: Ethical Considerations Surrounding Population-Based Newborn Genome Screening for Hearing

Recent advances in genomic sequencing technologies have expanded practitioners’ utilization of genetic information in a timely and efficient manner for an accurate diagnosis. With an ever-increasing resource of genomic data from progress in the interpretation of genome sequences, clinicians face decisions about how and when genomic information should be presented to families, and at what potential expense. Presently, there is limited knowledge or experience in establishing the value of implementing genome sequencing into newborn screening. Herein we provide insight into the complexities and the burden and benefits of knowledge resulting from genome sequencing of newborns