Purpose: Previously, we showed that tear fluid protects corneal epithelial cells against Pseudomonas aeruginosa without suppressing bacterial viability. Here, we studied how tear fluid affects bacterial gene expression.
Methods: RNA-sequencing was used to study the P. aeruginosa transcriptome after tear fluid exposure (5 h, 37 C). Outcomes were further investigated by biochemical and physiological perturbations to tear fluid and tear-like fluid (TLF) and assessment of bacterial viability following tear/TLF pretreatment and antibiotic exposure.
Results: Tear fluid deregulated ~180 P. aeruginosa genes ≥8 fold versus PBS including downregulating lasI, rhlI, qscR (quorum sensing/virulence), oprH, phoP, phoQ (antimicrobial resistance) and arnBCADTEF (polymyxin B resistance). Upregulated genes included algF (biofilm formation) and hemO (iron acquisition). qPCR confirmed tear down-regulation of oprH, phoP and phoQ. Tear fluid pre-treatment increased P. aeruginosa resistance to meropenem ~5-fold (4 μg/ml), but enhanced polymyxin B susceptibility ~180-fold (1 μg/ml), the latter activity reduced by dilution in PBS. Media containing a subset of tear components (TLF) also sensitized bacteria to polymyxin B, but only ~22.5-fold, correlating with TLF/tear fluid Ca and Mg concentrations. Accordingly, phoQ mutants were not sensitized by TLF or tear fluid. Superior activity of tear fluid versus TLF against wild-type P. aeruginosa was heat resistant but proteinase K sensitive.
Conclusion: P. aeruginosa responds to human tear fluid by upregulating genes associated with bacterial survival and adaptation. Meanwhile, tear fluid down-regulates multiple virulence-associated genes. Tears also utilize divalent cations and heat resistant/proteinase K sensitive component(s) to enhance P. aeruginosa sensitivity to polymyxin B.
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http://dx.doi.org/10.1016/j.jtos.2021.07.004 | DOI Listing |
J Craniofac Surg
December 2024
Alder Hey Children's Hospital, Eaton Road, Liverpool, UK.
Introduction: Posterior vault distraction osteogenesis (PVDO) allows significant increase in intracranial volume but is associated with complications including cerebrospinal fluid (CSF) leaks, infection and device failure. The authors outline their outcomes over 12 years and the impact of PVDO on pre-existing Chiari malformation type 1 (CM).
Method: Retrospective review of all PVDOs in our unit over a period of 12 years from 2011 to 2023.
Ophthalmic Plast Reconstr Surg
December 2024
Adnexal Service, Moorfields Eye Hospital, London, United Kingdom.
Purpose: To relate dacryoscintillographic features to presenting symptoms and signs for watery-eyed patients with patent drainage systems.
Methods: Retrospective case note and imaging review for patients with watering eye(s) and clinical evidence of impaired tear drainage who underwent dacryoscintillography (DSG). Three DSG features were graded, along with 4 symptoms, 7 signs, and the degree of fluid reflux and nasal fluid passage on gentle syringing.
AJOG Glob Rep
February 2025
Mother and Child Welfare Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran (all authors).
Background: Episiotomy has specific indications that, if properly followed, can effectively prevent women from experiencing severe lacerations that may result in significant complications like anal incontinence. However, the risk factors related to episiotomy has been the center of much debate in the medical field in the past few years.
Objective: The present study used a machine learning model to predict the factors that put women at the risk of having episiotomy using intrapartum data.
Chem Asian J
December 2024
Indian Institute of Technology Ropar, Department of Chemistry, Bara Phool, 140001, Rupnagar, INDIA.
Ocular drug-delivery is one of the most challenging areas owing to nature of ocular tissues. Various nanoformulations have been designed and investigated for drug-delivery to achieve high drug bioavailability. The major focus of preparations available in market is to utilize nanomaterial as drug-carrier, with less focus on developing functional-nanomaterials, which is a key knowledge gap in the field.
View Article and Find Full Text PDFNanomicro Lett
December 2024
School of Microelectronics, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China.
Ammonium level in body fluids serves as one of the critical biomarkers for healthcare, especially those relative to liver diseases. The continuous and real-time monitoring in both invasive and non-invasive manners is highly desired, while the ammonium concentrations vary largely in different body fluids. Besides, the sensing reliability based on ion-selective biosensors can be significantly interfered by potassium ions.
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