Author Correction: Robust estimation of bacterial cell count from optical density

An amendment to this paper has been published and can be accessed via a link at the top of the paper.</jats:p

Robust estimation of bacterial cell count from optical density

AbstractOptical 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  &lt;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.</jats:p

Perinatal characteristics and neonatal outcomes of singletons and twins in Chinese very preterm infants: a cohort study

Abstract Background The prevalence of preterm birth has been rising, and there is a paucity of nationwide data on the perinatal characteristics and neonatal outcomes of twin deliveries of very preterm infants (VPIs) in China. This study compared the perinatal characteristics and outcomes of singletons and twins admitted to neonatal intensive care units (NICUs) in China. Methods The study population comprised all infants born before 32 weeks in the Chinese Neonatal Network (CHNN) between January 2019 and December 2019. Three-level and population-average generalized estimating equation (GEE)/alternating logistic regression (ALR) models were used to determine the association of twins with neonatal morbidities and the use of NICU resources. Results During the study period, there were 6634 (71.2%) singletons and 2680 (28.8%) twins, with mean birth weights of 1333.70 g and 1294.63 g, respectively. Twins were significantly more likely to be delivered by caesarean section (p &lt; 0.01), have antenatal steroid usage (p = 0.048), have been conceived by assisted reproductive technology (ART) (p &lt; 0.01), have a higher prevalence of maternal diabetes (p &lt; 0.01) and be inborn (p &lt; 0.01) than singletons. In addition, twins had a lower prevalence of small for gestational age, maternal hypertension, and primigravida mothers than singletons (all p &lt; 0.01). After adjusting for potential confounders, twins had higher mortality rates (adjusted odds ratio [AOR] 1.28, 95% confidence interval [CI] 1.10–1.49), higher incidences of short-term composite outcomes (AOR 1.28, 95% CI 1.09–1.50), respiratory distress syndrome (RDS) (AOR 1.30, 95% CI 1.12–1.50), and bronchopulmonary dysplasia (BPD) (AOR 1.10, 95% CI 1.01–1.21), more surfactant usage (AOR 1.22, 95% CI 1.05–1.41) and prolonged hospital stays (adjusted mean ratio 1.03, 95% CI 1.00–1.06), compared to singletons. Conclusion Our work suggests that twins have a greater risk of mortality, a higher incidence of RDS and BPD, more surfactant usage, and longer NICU stays than singletons among VPIs in China. </jats:sec