46 research outputs found

    Stepwise evolution of Salmonella Typhimurium ST313 causing bloodstream infection in Africa

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    Bloodstream infections caused by nontyphoidal Salmonella are a major public health concern in Africa, causing ~49,600 deaths every year. The most common Salmonella enterica pathovariant associated with invasive nontyphoidal Salmonella disease is Salmonella Typhimurium sequence type (ST)313. It has been proposed that antimicrobial resistance and genome degradation has contributed to the success of ST313 lineages in Africa, but the evolutionary trajectory of such changes was unclear. Here, to define the evolutionary dynamics of ST313, we sub-sampled from two comprehensive collections of Salmonella isolates from African patients with bloodstream infections, spanning 1966 to 2018. The resulting 680 genome sequences led to the discovery of a pan-susceptible ST313 lineage (ST313 L3), which emerged in Malawi in 2016 and is closely related to ST313 variants that cause gastrointestinal disease in the United Kingdom and Brazil. Genomic analysis revealed degradation events in important virulence genes in ST313 L3, which had not occurred in other ST313 lineages. Despite arising only recently in the clinic, ST313 L3 is a phylogenetic intermediate between ST313 L1 and L2, with a characteristic accessory genome. Our in-depth genotypic and phenotypic characterization identifies the crucial loss-of-function genetic events that occurred during the stepwise evolution of invasive S. Typhimurium across Africa

    Analysis of the code and carrier phase measurements performed with LEA-6T GPS receiver

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    Discordance Between Perceptions and Experience of Lumbar Puncture: A Prospective Study

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    BACKGROUND AND OBJECTIVES: Novel diagnostic techniques and neurologic biomarkers have greatly expanded clinical indications for CSF studies. CSF is most commonly obtained via lumbar puncture (LP). Although it is generally believed that LPs are well tolerated, there is a lack of supportive data for this claim, and patients anticipate LP to be painful. The objective of this study was to prospectively investigate discordance between patient perception and tolerability of LP. METHODS: Adult patients were surveyed before and after LP regarding their perceptions and experience of LP. Physician perceptions were gathered through a web-based survey. Relative risk and Spearman correlation were used to assess the relationship between responses. Paired binomial and paired ordinal responses were compared by McNemar and paired Wilcoxon rank-sum tests. RESULTS: A total of 178 patients completed the surveys. About half of the patients (58%) reported anxiety pre-LP, at median 3.0 of 10. Physicians overpredicted patients\u27 pre-LP anxiety (median score 5.0, \u3c 0.001). Experienced pain was significantly less than predicted pain (median scores 0 and 3.0, respectively, \u3c 0.001). Patients who predicted pain were more likely to report pain from LP (relative risk [RR] 1.3). Predicting pain was also correlated with anxiety before LP ( \u3c 0.001). DISCUSSION: LP was generally well tolerated. The majority of patients experienced minimal pain. Anticipation of pain was correlated with both feeling anxious and experiencing pain. The results of this study can be used to reassure patients and providers that LP is indeed not as painful as imagined, which may both reduce pre-LP anxiety and improve LP tolerability
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