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Antibiotics that use novel mechanisms are needed to combat antimicrobial resistance1-3. Teixobactin4 represents a new class of antibiotics with a unique chemical scaffold and lack of detectable resistance. Teixobactin targets lipid II, a precursor of peptidoglycan5. Here we unravel the mechanism of teixobactin at the atomic level using a combination of solid-state NMR, microscopy, in vivo assays and molecular dynamics simulations. The unique enduracididine C-terminal headgroup of teixobactin specifically binds to the pyrophosphate-sugar moiety of lipid II, whereas the N terminus coordinates the pyrophosphate of another lipid II molecule. This configuration favours the formation of a β-sheet of teixobactins bound to the target, creating a supramolecular fibrillar structure. Specific binding to the conserved pyrophosphate-sugar moiety accounts for the lack of resistance to teixobactin4. The supramolecular structure compromises membrane integrity. Atomic force microscopy and molecular dynamics simulations show that the supramolecular structure displaces phospholipids, thinning the membrane. The long hydrophobic tails of lipid II concentrated within the supramolecular structure apparently contribute to membrane disruption. Teixobactin hijacks lipid II to help destroy the membrane. Known membrane-acting antibiotics also damage human cells, producing undesirable side effects. Teixobactin damages only membranes that contain lipid II, which is absent in eukaryotes, elegantly resolving the toxicity problem. The two-pronged action against cell wall synthesis and cytoplasmic membrane produces a highly effective compound targeting the bacterial cell envelope. Structural knowledge of the mechanism of teixobactin will enable the rational design of improved drug candidates.

Lyme disease (also known as Lyme borreliosis) is the most common vector-borne disease in the United States with an estimated 476,000 cases per year. While historically, the long-term impact of Lyme disease on patients has been controversial, mounting evidence supports the idea that a substantial number of patients experience persistent symptoms following treatment. The research community has largely lacked the necessary funding to properly advance the scientific and clinical understanding of the disease, or to develop and evaluate innovative approaches for prevention, diagnosis, and treatment. Given the many outstanding questions raised into the diagnosis, clinical presentation and treatment of Lyme disease, and the underlying molecular mechanisms that trigger persistent disease, there is an urgent need for more support. This review article summarizes progress over the past 5 years in our understanding of Lyme and tick-borne diseases in the United States and highlights remaining challenges.

Lyme disease is the most common vector-borne disease in the United States, with an estimated incidence of 300,000 infections annually. Antibiotic intervention cures Lyme disease in the majority of cases; however, 10 to 20% of patients develop posttreatment Lyme disease syndrome (PTLDS), a debilitating condition characterized by chronic fatigue, pain, and cognitive difficulties. The underlying mechanism responsible for PTLDS symptoms, as well as a reliable diagnostic tool, has remained elusive. We reasoned that the gut microbiome may play an important role in PTLDS given that the symptoms overlap considerably with conditions in which a dysbiotic microbiome has been observed, including mood, cognition, and autoimmune disorders. Analysis of sequencing data from a rigorously curated cohort of patients with PTLDS revealed a gut microbiome signature distinct from that of healthy control subjects, as well as from that of intensive care unit (ICU) patients. Notably, microbiome sequencing data alone were indicative of PTLDS, which presents a potential, novel diagnostic tool for PTLDS.IMPORTANCE Most patients with acute Lyme disease are cured with antibiotic intervention, but 10 to 20% endure debilitating symptoms such as fatigue, neurological complications, and myalgias after treatment, a condition known as posttreatment Lyme disease syndrome (PTLDS). The etiology of PTLDS is not understood, and objective diagnostic tools are lacking. PTLDS symptoms overlap several diseases in which patients exhibit alterations in their microbiome. We found that patients with PTLDS have a distinct microbiome signature, allowing for an accurate classification of over 80% of analyzed cases. The signature is characterized by an increase in Blautia, a decrease in Bacteroides, and other changes. Importantly, this signature supports the validity of PTLDS and is the first potential biological diagnostic tool for the disease.

This report describes the first synthesis and application of a fluorescent teixobactin analogue that exhibits antibiotic activity and binds to the cell walls of Gram-positive bacteria. The teixobactin analogue, Lys(Rhod)9,Arg10-teixobactin, has a fluorescent tag at position 9 and an arginine in place of the natural allo-enduracididine residue at position 10. The fluorescent teixobactin analogue retains partial antibiotic activity, with minimum inhibitory concentrations of 4-8 μg/mL across a panel of Gram-positive bacteria, as compared to 1-4 μg/mL for the unlabeled Arg10-teixobactin analogue. Lys(Rhod)9,Arg10-teixobactin is prepared by a regioselective labeling strategy that labels Lys9 with an amine-reactive rhodamine fluorophore during solid-phase peptide synthesis, with the resulting conjugate tolerating subsequent solid-phase peptide synthesis reactions. Treatment of Gram-positive bacteria with Lys(Rhod)9,Arg10-teixobactin results in septal and lateral staining, which is consistent with an antibiotic targeting cell wall precursors. Concurrent treatment of Lys(Rhod)9,Arg10-teixobactin and BODIPY FL vancomycin results in septal colocalization, providing further evidence that Lys(Rhod)9,Arg10-teixobactin binds to cell wall precursors. Controls with either Gram-negative bacteria, or an inactive fluorescent homologue with Gram-positive bacteria, showed little or no staining in fluorescence micrographic studies. Lys(Rhod)9,Arg10-teixobactin can thus serve as a functional probe to study Gram-positive bacteria and their interactions with teixobactin.

International initiatives to strengthen national health laboratory systems in resource-poor countries are often hampered by unfamiliarity with the country's health laboratory environment and turnover of international partners during the initiative. This study provides an overview of, and lessons learned from, the use of a laboratory long-term partnership approach (ie, "twinning") to strengthen the national public health laboratory system in an international setting. We focused on the partnering of the Uganda Ministry of Health Central Public Health Laboratory (CPHL) with the New Mexico State Public Health Laboratory to help the CPHL become Uganda's national public health reference laboratory (Uganda National Health Laboratory Services [UNHLS] Institute) and leader of its nascent Uganda National Health Laboratory Network (UNHLN). Via twinning, CPHL leadership received training on laboratory leadership and management, quality systems, facility management, and the One Health environmental strategy (ie, that the health of persons is connected to the health of animals and the environment), and drafted a National Health Laboratory Policy, UNHLS Institute business plan, and strategic and operating plans for the UNHLS Institute and UNHLN. The CPHL is now responsible for the UNHLS Institute and coordinates the UNHLN. Lessons learned include (1) twinning establishes stable long-term collaborations and (2) success requires commitment to a formal statement of activities and objectives, as well as clear and regular communication among partners.

The gut microbiota affects many important host functions, including the immune response and the nervous system1. However, while substantial progress has been made in growing diverse microorganisms of the microbiota2, 23-65% of species residing in the human gut remain uncultured3,4, which is an obstacle for understanding their biological roles. A likely reason for this unculturability is the absence in artificial media of key growth factors that are provided by neighbouring bacteria in situ5,6. In the present study, we used co-culture to isolate KLE1738, which required the presence of Bacteroides fragilis to grow. Bioassay-driven purification of B. fragilis supernatant led to the isolation of the growth factor, which, surprisingly, is the major inhibitory neurotransmitter GABA (γ-aminobutyric acid). GABA was the only tested nutrient that supported the growth of KLE1738, and a genome analysis supported a GABA-dependent metabolism mechanism. Using growth of KLE1738 as an indicator, we isolated a variety of GABA-producing bacteria, and found that Bacteroides ssp. produced large quantities of GABA. Genome-based metabolic modelling of the human gut microbiota revealed multiple genera with the predicted capability to produce or consume GABA. A transcriptome analysis of human stool samples from healthy individuals showed that GABA-producing pathways are actively expressed by Bacteroides, Parabacteroides and Escherichia species. By coupling 16S ribosmal RNA sequencing with functional magentic resonance imaging in patients with major depressive disorder, a disease associated with an altered GABA-mediated response, we found that the relative abundance levels of faecal Bacteroides are negatively correlated with brain signatures associated with depression.

Purpose: This study examined differences in selected acoustic measures of speech and voice according to age and sex and across families. Method: Participants included 169 individuals, 79 men and 90 women, from 18 families, ranging in age from 17 to 87 years. Participants reported no history of articulation disorders, stroke or active neurologic disease, or severe-to-profound hearing loss. They read aloud two passages to facilitate examination of the following speech and voice acoustic parameters: fricative spectral moments (center of gravity, standard deviation, skewness, and kurtosis), the proportion of time spent speaking, mean speaking fundamental frequency, semitone standard deviation (STSD), and cepstral peak prominence smoothed. Results: The results indicated a significant age effect for fricative spectral center of gravity, spectral skewness, and speaking STSD. There was a significant sex effect for spectral center of gravity, spectral kurtosis, and mean fundamental frequency. Familial relationship was significant for spectral skewness, STSD, and cepstral peak prominence smoothed. Conclusions: These findings revealed that certain speech and voice features change with age and some change differently for men and women. Additionally, speakers from the same family units may demonstrate similar patterns for prosody, voicing, and articulatory behavior. The results also demonstrated normal differences in speech and voice variation across age, sex, and family unit. Understanding patterns and differences across these demographic variables in healthy speakers is important to distinguishing more confidently between normal and disordered speech and voice patterns clinically.

Introduction Methods Results Conclusion Preliminary image evaluation (PIE) is a system where radiographers alert emergency department referrers to the presence or absence of abnormalities on acute extremity X‐ray examinations. PIE and similar systems have been utilised in the United Kingdom (UK) and Australia due to a shortage of radiologists to provide a timely report. As New Zealand (NZ) faces a similar shortage, PIE should be considered to address the negative impact this has on patients. The aim of this study was to determine the effect of regular feedback and education on radiographers' performance when detecting and describing acute abnormalities on extremity X‐ray examinations in ED.A prospective longitudinal study design was utilised for this study. The sensitivity, specificity, accuracy, and accuracy of PIEs performed by seven radiographers at a public provincial district in NZ were assessed over a 6‐month period, with the participants provided monthly results along with regular e‐mailed feedback on common errors.The mean for sensitivity, specificity, and accuracy calculated with a 95% confidence interval over the 6‐month period were 92.8% (89.9, 95.8), 94.9 (93.1, 96.8), and 94.2 (91.9, 96.5), respectively. When the month‐to‐month results were analysed, the results demonstrated an improvement in participants' sensitivity, specificity, and accuracy over the 6‐month period.The results of this study demonstrated that radiographers who participated in the study can perform PIE to a high standard that is comparable with the findings from international studies and demonstrated an improvement over 6 months. Therefore, PIE may be useful in NZ to aid ED clinicians in their clinical decisions when a radiology report is unavailable. [ABSTRACT FROM AUTHOR]