Mycobacterium tuberculosis Responds to Chloride and pH as Synergistic Cues to the Immune Status of its Host Cell

PubMed ID: 23592993This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Molecular targets for rapid identification of Brucella spp

BACKGROUND: Brucella is an intracellular pathogen capable of infecting animals and humans. There are six recognized species of Brucella that differ in their host preference. The genomes of the three Brucella species have been recently sequenced. Comparison of the three revealed over 98% sequence similarity at the protein level and enabled computational identification of common and differentiating genes. We validated these computational predictions and examined the expression patterns of the putative unique and differentiating genes, using genomic and reverse transcription PCR. We then screened a set of differentiating genes against classical Brucella biovars and showed the applicability of these regions in the design of diagnostic tests. RESULTS: We have identified and tested set of molecular targets that are associated in unique patterns with each of the sequenced Brucella spp. A comprehensive comparison was made among the published genome sequences of B. abortus, B. melitensis and B. suis. The comparison confirmed published differences between the three Brucella genomes, and identified subsets of features that were predicted to be of interest in a functional comparison of B. melitensis and B. suis to B. abortus. Differentiating sequence regions from B. abortus, B. melitensis and B. suis were used to develop PCR primers to test for the existence and in vitro transcription of these genes in these species. Only B. suis is found to have a significant number of unique genes, but combinations of genes and regions that exist in only two out of three genomes and are therefore useful for diagnostics were identified and confirmed. CONCLUSION: Although not all of the differentiating genes identified were transcribed under steady state conditions, a group of genes sufficient to discriminate unambiguously between B. suis, B. melitensis, and B. abortus was identified. We present an overview of these genomic differences and the use of these features to discriminate among a number of Brucella biovars

Recovery from COVID-19 and Acute Respiratory Distress Syndrome: The Potential Role of an Intensive Care Unit Recovery Clinic: A Case Report

Background In this case report, we describe the trajectory of recovery of a young, healthy patient diagnosed with coronavirus disease 2019 who developed acute respiratory distress syndrome. The purpose of this case report is to highlight the potential role of intensive care unit recovery or follow-up clinics for patients surviving acute hospitalization for coronavirus disease 2019. Case Presentation Our patient was a 27-year-old Caucasian woman with a past medical history of asthma transferred from a community hospital to our medical intensive care unit for acute hypoxic respiratory failure due to bilateral pneumonia requiring mechanical ventilation (ratio of arterial oxygen partial pressure to fraction of inspired oxygen, 180). On day 2 of her intensive care unit admission, reverse transcription–polymerase chain reaction confirmed coronavirus disease 2019. Her clinical status gradually improved, and she was extubated on intensive care unit day 5. She had a negative test result for coronavirus disease 2019 twice with repeated reverse transcription–polymerase chain reaction before being discharged to home after 10 days in the intensive care unit. Two weeks after intensive care unit discharge, the patient returned to our outpatient intensive care unit recovery clinic. At follow-up, the patient endorsed significant fatigue and exhaustion with difficulty walking, minor issues with sleep disruption, and periods of memory loss. She scored 10/12 on the short performance physical battery, indicating good physical function. She did not have signs of anxiety, depression, or post-traumatic stress disorder through self-report questionnaires. Clinically, she was considered at low risk of developing post–intensive care syndrome, but she required follow-up services to assist in navigating the healthcare system, addressing remaining symptoms, and promoting return to her pre–coronavirus disease 2019 societal role. Conclusion We present this case report to suggest that patients surviving coronavirus disease 2019 with subsequent development of acute respiratory distress syndrome will require more intense intensive care unit recovery follow-up. Patients with a higher degree of acute illness who also have pre-existing comorbidities and those of older age who survive mechanical ventilation for coronavirus disease 2019 will require substantial post–intensive care unit care to mitigate and treat post–intensive care syndrome, promote reintegration into the community, and improve quality of life

Probing host pathogen cross-talk by transcriptional profiling of both Mycobacterium tuberculosis and infected human dendritic cells and macrophages

This study provides the proof of principle that probing the host and the microbe transcriptomes simultaneously is a valuable means to accessing unique information on host pathogen interactions. Our results also underline the extraordinary plasticity of host cell and pathogen responses to infection, and provide a solid framework to further understand the complex mechanisms involved in immunity to M. tuberculosis and in mycobacterial adaptation to different intracellular environments

A novel assay of antimycobacterial activity and phagocytosis by human neutrophils

SummaryDespite abundant evidence that neutrophils arrive early at sites of mycobacterial disease and phagocytose organisms, techniques to assay phagocytosis or killing of mycobacteria by these cells are lacking. Existing assays for measuring the antimycobacterial activity of human leukocytes require cell lysis which introduces new bioactive substances and may be incomplete. They are also time-consuming and carry multiple risks of inaccuracy due to serial dilution and organism clumping. Flow cytometric techniques for measuring phagocytosis of mycobacteria by human cells have failed to adequately address the effects of organism clumping, quenching agents and culture conditions on readouts.Here we present a novel in-tube bioluminescence-based assay of antimycobacterial activity by human neutrophils. The assay yields intuitive results, with improving restriction of mycobacterial bioluminescence as the ratio of cells to organisms increases. We show that lysis of human cells is not required to measure luminescence accurately.We also present a phagocytosis assay in which we have minimised the impact of mycobacterial clumping, investigated the effect of various opsonisation techniques and established the correct usage of trypan blue to identify surface-bound organisms without counting dead cells. The same multiplicity of infection and serum conditions are optimal to demonstrate both internalisation and restriction of mycobacterial growth

Prime movers : mechanochemistry of mitotic kinesins

Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation

Increasing incidence of skin disorders in children? A comparison between 1987 and 2001

BACKGROUND: The increasing proportion of skin diseases encountered in general practice represents a substantial part of morbidity in children. Only limited information is available about the frequency of specific skin diseases. We aimed to compare incidence rates of skin diseases in children in general practice between 1987 and 2001. METHODS: We used data on all children aged 0–17 years derived from two consecutive surveys performed in Dutch general practice in 1987 and 2001. Both surveys concerned a longitudinal registration of GP consultations over 12 months. Each disease episode was coded according to the International Classification of Primary Care. Incidence rates of separate skin diseases were calculated by dividing all new episodes for each distinct ICPC code by the average study population at risk. Data were stratified for socio-demographic characteristics. RESULTS: The incidence rate of all skin diseases combined in general practice decreased between 1987 and 2001. Among infants the incidence rate increased. Girls presented more skin diseases to the GP. In the southern part of the Netherlands children consulted their GP more often for skin diseases compared to the northern part. Children of non-Western immigrants presented relatively more skin diseases to the GP. In general practice incidence rates of specific skin diseases such as impetigo, dermatophytosis and atopic dermatitis increased in 2001, whereas warts, contact dermatitis and skin injuries decreased. CONCLUSION: The overall incidence rate of all skin diseases combined in general practice decreased whereas the incidence rates of bacterial, mycotic and atopic skin diseases increased