Effect of the Lys62Ala Mutation on the Thermal Stability of BstHPr Protein by Molecular Dynamics.

We analyzed the thermal stability of the BstHPr protein through the site-directed point mutation Lys62 replaced by Ala residue using molecular dynamics simulations at five different temperatures: 298, 333, 362, 400, and 450 K, for periods of 1 µs and in triplicate. The results from the mutant thermophilic BstHPrm protein were compared with those of the wild-type thermophilic BstHPr protein and the mesophilic BsHPr protein. Structural and molecular interaction analyses show that proteins lose stability as temperature increases. Mutant and wild-type proteins behave similarly up to 362 K. However, at 400 K the mutant protein shows greater structural instability, losing more buried hydrogen bonds and exposing more of its non-polar residues to the solvent. Therefore, in this study, we confirmed that the salt bridge network of the Glu3-Lys62-Glu36 triad, made up of the Glu3-Lys62 and Glu36-Lys62 ion pairs, provides thermal stability to the thermophilic BstHPr protein.

Molecular Dynamics Simulations of HPr Proteins from a Thermophilic and a Mesophilic Organism: A Comparative Thermal Study.

The histidine-containing phosphocarrier (HPr) is a monomeric protein conserved in Gram-positive bacteria, which may be of mesophilic or thermophilic nature. In particular, the HPr protein from the thermophilic organism B. stearothermophilus is a good model system for thermostability studies, since experimental data, such as crystal structure and thermal stability curves, are available. However, its unfolding mechanism at higher temperatures is yet unclear at a molecular level. Therefore, in this work, we researched the thermal stability of this protein using molecular dynamics simulations, subjecting it to five different temperatures during a time span of 1 µs. The analyses of the structural parameters and molecular interactions were compared with those of the mesophilic homologue HPr protein from B. subtilis. Each simulation was run in triplicate using identical conditions for both proteins. The results showed that the two proteins lose stability as the temperature increases, but the mesophilic structure is more affected. We found that the salt bridge network formed by the triad of Glu3-Lys62-Glu36 residues and the salt bridge made up of Asp79-Lys83 ion pair are key factors to keep stable the thermophilic protein, maintaining the hydrophobic core protected and the structure packed. In addition, these molecular interactions neutralize the negative surface charge, acting as "natural molecular staples".

Descriptive management of suspected acute cystitis in adult patients by French general practitioners during remote consultation.

OBJECTIVES: The main objective of this study was to analyze French general practitioners' (GP) online prescriptions for suspected acute cystitis using a single nationwide teleconsultation platform. PATIENTS AND METHODS: First, a descriptive study of management for suspected cystitis was conducted from the 1st of January to the 31st of December 2020. After which, following pedagogical intervention, a pre/post descriptive analysis of the antibiotics prescribed was carried out. RESULTS: Some 496,041 teleconsultations (TCs) were carried out in 2020 on the Qare platform. Among them, 15,089 TCs for cystitis with ICD-10 encoding (N30) were analyzed. Fosfomycin trometamol was the most prescribed antibiotic (n = 10297, 69%), while fluoroquinolones (n = 1568, 10.6%) were the second. Urine test strip was prescribed in 3157 (20%) and urine culture in 7033 (47%) of the TCs. July-August 2020 and July-August 2021 were compared and while a significant drop in fluoroquinolone prescriptions and a major increase in Fosfomycin trometamol were observed, there was no change in the prescriptions of urine culture. An average antibiotic conformity rate of 61.5% was observed before the intervention, and 68.8% afterwards. CONCLUSIONS: Cystitis is a recurrent reason for remote consultation. The study demonstrated sizable over-prescription of urine culture, ultrasound, and fluoroquinolones. Intervention should be improved and strengthened to guarantee continuous training and awareness of GP's on appropriate cystitis prescriptions in telemedicine.

Resistance-minimizing strategies for introducing a novel antibiotic for gonorrhea treatment: a mathematical modeling study.

Background: Gonorrhea is a highly prevalent sexually transmitted infection and an urgent public health concern due to increasing antibiotic resistance. Only ceftriaxone remains as the recommended treatment in the U.S. The prospect of approval of new anti-gonococcal antibiotics raises the question of how to deploy a new drug to maximize its clinically useful lifespan. Methods: We used a compartmental model of gonorrhea transmission in the U.S. population of men who have sex with men to compare strategies for introducing a new antibiotic for gonorrhea treatment. The strategies tested included holding the new antibiotic in reserve until the current therapy reached a threshold prevalence of resistance; using either drug, considering immediate and gradual introduction of the new drug; and combination therapy. The primary outcome of interest was the time until 5% prevalence of resistance to both the novel drug and to the current first-line drug (ceftriaxone). Findings: The reserve strategy was consistently inferior for mitigating antibiotic resistance under the parameter space explored. The reserve strategy was increasingly outperformed by the other strategies as the probability of de novo resistance emergence decreased and as the fitness costs associated with resistance increased. Combination therapy tended to prolong the development of antibiotic resistance and minimize the number of annual gonococcal infections. Interpretation: Our study argues for rapid introduction of new anti-gonococcal antibiotics, recognizing that the feasibility of each strategy must incorporate cost, safety, and other practical concerns. The analyses should be revisited once robust estimates of key parameters-likelihood of emergence of resistance and fitness costs of resistance for the new antibiotic-are available. Funding: U.S. Centers for Disease Control and Prevention (CDC), National Institute of Allergy and Infectious Diseases.

Appropriateness of Antibiotic Prescription During Teleconsultation.

Teleconsultation has become a new means of using care which has taken off significantly since the COVID crisis, The pooling of the technological environment within the TC makes it possible to set up practice reviews by reusing the data collected. Our aim was to evaluate the relevance of antibiotic therapy during teleconsultations carried out on the national teleconsultation platform "Qare" in 4 common infections. 143,428 TCs with structured prescriptions were analyzed, with an appropriate prescription in more than 82% of cases, higher than in the literature. The use of data makes it possible to quickly assess practices and inform doctors to improve their practices.

Improving coarse-grained models of protein folding through weighting of polar-polar/hydrophobic-hydrophobic interactions into crowded spaces.

Herein were tested 7 hydrophobic-polar sequences in two types of 2D-square space lattices, homogeneous and correlated, the latter simulating molecular crowding included as a geometric boundary restriction. Optimization of 2D structures was carried out using a variant of Dill's model, inspired by convex function, taking into account both hydrophobic (Dill's model) and polar interactions, including more structural information to reach better folding solutions. While using correlated networks, degrees of freedom in the folding of sequences were limited; as a result in all cases, more successful structural trials were found in comparison to a homogeneous lattice. The majority of employed sequences were designed by our workgroup, two of them were folded with other approaches, and another is a modified version of a previous sequence, initial forms of the other two have been employed but without taking into account polar-polar contributions. Three of them are newly proposed, intended to test the conjoint hydrophobic-hydrophobic and polar-polar contributions in crowded spaces. One sequence turned out to be the most difficult of the seven folded, this perhaps due to intrinsic (i) degrees of freedom and (ii) motifs of the expected 2D HP structure. Meanwhile two-sequence, although optimal folding was not achieved for neither of the two approaches, folding with correlated network approach not only produced better results than homogeneous space, but for them the best values found with crowding were very close to the expected optimal fitness. In general, five sequences were better folded with medium lattice units for correlated media; instead, another two sequences were better folded with a bit larger degree of lattice unit, revealing that depending on the degrees of freedom and particular folding, motifs in each sequence would require tuned crowding to achieve better folding. Therefore, the main goal herein was to obtain a modified 2D HP lattice model to mimic folding of proteins or secondary structures, like ß-sheets, taking into account both hydrophobic-hydrophobic and polar-polar interactions, and fold them in a crowded environment. This simple but enough construction would be conducted to determine the needed information to fold sequences in a sort of a minimal but complete heuristic model. Finally, we claim that all folded sequences into crowded spaces achieve better results than homogeneous ones.

Effect of bioactive compounds extracted from Cordyceps nidus ANDES-F1080 on laccase activity of Pleurotus ostreatus ANDES-F515.

Laccases are ligninolytic enzymes produced by different microorganisms, especially by fungi such as the white-rot fungus Pleurotus ostreatus. Chemical inductors have been used to promote laccase secretion due to the application of these enzymes in lignocellulosic biomass pretreatment. Cordyceps nidus ANDES-F1080 was previously described as a source of bioactive compounds that could influence the enzymatic production system of other fungi. For that reason, this study evaluates the effect of C. nidus' ANDES-F1080 extracts on the laccase activity of P. ostreatus ANDES-F515. To achieve this objective, C. nidus ANDES-F1080 was grown in four different substrates: two artificial-based and two natural-based culture media. Metabolites were extracted from C. nidus ANDES-F1080 using water and methanol as solvents. Biochemical characterization of these extracts was performed to complement the analysis of their effect on laccase activity. Our results revealed an enhancement on the laccase activity of P. ostreatus ANDES-F515 grown in natural-based cultures when C. nidus' ANDES-F1080 extracts were supplemented. The best laccase activities registered values around 10,575 ±â€¯813 U·L-1.

On the Thermal Stability of O6-Methylguanine-DNA Methyltransferase from Archaeon Pyrococcus kodakaraensis by Molecular Dynamics Simulations.

We have employed molecular dynamics simulations to analyze the thermal stability of the O6-methylguanine-DNA methyltransferase (MGMT) protein, both hyperthermophilic archaeon Pyrococcus kodakaraensis (Pk-MGMT) and its mesophilic homologue pair, obtained from enterobacterium Escherichia coli (AdaC). This theoretical study was done at three different temperatures: 302, 371, and 450 K. The molecular dynamics has been performed in explicit aqueous solvent during a period of time of 95 ns, including periodic boundary conditions and constant pressure. The same procedure has been used for both proteins, and each simulation has been carried out by triplicate. Hence, we performed 18 simulations. In this way, we have done different analyses to explore the factors that may affect the thermal stability of Pk-MGMT. The structural behavior was analyzed using indicators such as root-mean-square deviation, radius of gyration, solvent-accessible surface area, hydrogen bonds, native contacts, secondary structure, and salt bridge formation. The results showed that when the temperature increases, the global atomic fluctuations increase too, which suggests that both proteins lose thermal stability, but as expected, this fact is highlighted in AdaC. Moreover, the contacts of the native state in AdaC are considerably lower than those found in Pk-MGMT at 450 K. Also, the structural studies showed that conserved and nonconserved salt bridges kept close contacts with the Pk-MGMT protein at high temperatures. These interaction types act as molecular staples and are mainly responsible to provide thermostability to the hyperthermophilic protein.

Self-rated health scores predict mortality among people with type 2 diabetes differently across three different country groupings: findings from the ADVANCE and ADVANCE-ON trials.

AIMS: To explore whether there is a different strength of association between self-rated health and all-cause mortality in people with type 2 diabetes across three country groupings: nine countries grouped together as 'established market economies'; Asia; and Eastern Europe. METHODS: The ADVANCE trial and its post-trial follow-up were used in this study, which included 11 140 people with type 2 diabetes from 20 countries, with a median follow-up of 9.9 years. Self-rated health was reported on a 0-100 visual analogue scale. Cox proportional hazard models were fitted to estimate the relationship between the visual analogue scale score and all-cause mortality, controlling for a range of demographic and clinical risk factors. Interaction terms were used to assess whether the association between the visual analogue scale score and mortality varied across country groupings. RESULTS: The visual analogue scale score had different strengths of association with mortality in the three country groupings. A 10-point increase in visual analogue scale score was associated with a 15% (95% CI 12-18) lower mortality hazard in the established market economies, a 25% (95% CI 21-28) lower hazard in Asia, and an 8% (95% CI 3-13) lower hazard in Eastern Europe. CONCLUSIONS: Self-rated health appears to predict 10-year all-cause mortality for people with type 2 diabetes worldwide, but this relationship varies across groups of countries.

Unconventional diagnostic tests for Lyme borreliosis: a systematic review.

BACKGROUND: Lyme borreliosis (LB) diagnosis currently relies mainly on serological tests and sometimes PCR or culture. However, other biological assays are being developed to try to improve Borrelia-infection diagnosis and/or monitoring. OBJECTIVES: To analyse available data on these unconventional LB diagnostic assays through a systematic literature review. METHODS: We searched PubMed and Cochrane Library databases according to the PRISMA-DTA method and the Cochrane Handbook for Systematic Reviews of Interventions. We analysed controlled and uncontrolled studies (published 1983-2018) on biological tests for adults to diagnose LB according to the European Study Group for Lyme Borreliosis or the Infectious Diseases Society of America definitions, or identify strongly suspected LB. Two independent readers evaluated study eligibility and extracted data from relevant study reports; a third reader analysed full texts of papers to resolve disagreements. The quality of each included study was assessed with the QUADAS-2 evaluation scale. RESULTS: Forty studies were included: two meta-analyses, 25 prospective controlled studies, five prospective uncontrolled studies, six retrospective controlled studies and two case reports. These biological tests assessed can be classified as: (i) proven to be effective at diagnosing LB and already in use (CXCL-13 for neuroborreliosis), but not enough to be standardized; (ii) not yet used routinely, requiring further clinical evaluation (CCL-19, OspA and interferon-α); (iii) uncertain LB diagnostic efficacy because of controversial results and/or poor methodological quality of studies evaluating them (lymphocyte transformation test, interferon-γ, ELISPOT); (iv) unacceptably low sensitivity and/or specificity (CD57+ natural killer cells and rapid diagnostic tests); and (v) possible only for research purposes (microscopy and xenodiagnoses). DISCUSSION: QUADAS-2 quality assessment demonstrated high risk of bias in 25/40 studies and uncertainty regarding applicability for 32/40, showing that in addition to PCR and serology, several other LB diagnostic assays have been developed but their sensitivities and specificities are heterogeneous and/or under-evaluated or unassessed. More studies are warranted to evaluate their performance parameters. The development of active infection biomarkers would greatly advance LB diagnosis and monitoring.

Hospitalisations with infections related to antimicrobial-resistant bacteria from the French nationwide hospital discharge database, 2016.

Massive use of antibiotics has led to increased bacterial resistance to these drugs, making infections more difficult to treat. Few studies have assessed the overall antimicrobial resistance (AMR) burden, and there is a paucity of comprehensive data to inform health policies. This study aims to assess the overall annual incident number of hospitalised patients with AMR infection in France, using the National Hospital Discharge database. All incident hospitalisations with acute infections in 2016 were extracted. Infections which could be linked with an infecting microorganism were first analysed. Then, an extrapolation of bacterial species and resistance status was performed, according to age class, gender and infection site to estimate the total number of AMR cases. Resistant bacteria caused 139 105 (95% CI 127 920-150 289) infections, resulting in a 12.3% (95% CI 11.3-13.2) resistance rate. ESBL-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus were the most common resistant bacteria (>50%), causing respectively 49 692 (95% CI 47 223-52 142) and 19 493 (95% CI 15 237-23 747) infections. Although assumptions are needed to provide national estimates, information from PMSI is comprehensive, covering all acute bacterial infections and a wide variety of microorganisms.

Management of established pressure ulcer infections in spinal cord injury patients.

OBJECTIVES: Pressure ulcers are frequently observed in spinal cord injury (SCI) patients. They can be life-threatening and are a major medico-economic burden. Despite their frequency, their pathophysiology and optimal management are still poorly understood. Most available data comes from non-comparative studies, especially in terms of antimicrobial use. METHODS: We performed a critical review of the literature and opinions of infectious disease specialists based in a French expert center for this disease. We mainly focused on antimicrobial treatments prescribed in this situation. RESULTS: These infections are usually clinically diagnosed. Microbiological samples are not the gold standard for this assessment. Furthermore, reliable microbiological identification is a major challenge but should help select antimicrobial treatment. Imaging technique could be helpful but cannot replace the physical examination. The choice of antimicrobials must consider the potential ecological collateral damages in this vulnerable population. Antimicrobial therapy should be as short as possible, adapted to the microbiological identification, and must have suitable bioavailability. CONCLUSION: Management of infected pressure ulcers is a major concern in disabled patients already highly exposed to antimicrobial treatment and multidrug-resistant organisms colonization. Extensive data is required.

Fecal microbiota transplantation to eradicate vancomycin-resistant enterococci colonization in case of an outbreak.

OBJECTIVE: A rapid and worrying emergence of vancomycin-resistant enterococci (VRE) gut colonization is occurring worldwide and may be responsible for outbreaks, especially in healthcare facilities. While no efficient decolonization strategies are recommended, we assessed fecal microbiota transplantation (FMT) to eradicate VRE colonization. PATIENTS AND METHOD: Our main objective was to measure the impact of FMT on decolonization of VRE carriers, confirmed by at least two consecutive negative rectal swabs at one-week interval during a 3-month follow-up period. Patients received no antibiotic prior to the FMT. RESULTS: After a month only three patients remained colonized with VRE. Decolonization was associated with 87.5% (n=7) of success after three months as only one patient remained colonized. CONCLUSION: Our first results confirm that the FMT seems to be safe, with an impact on VRE colonization over time that may help control outbreaks.

[Original strategy for prevention of recurrent symptomatic urinary tract infections in patients with neurogenic bladder: Bacterial interference, state of the art]. / Stratégie préventive originale des infections urinaires symptomatiques chez les patients porteurs d'une vessie neurologique : l'interférence bactérienne, état de l'art.

PURPOSE: Urinary tract infection (UTI) is the most common complication in patients with neurogenic bladder. The long-term use of antibiotic drugs induces an increase in antimicrobial resistance and adverse drug reactions. Bacterial interference is a new concept to prevent recurrent UTI which consists in a bladder colonization with low virulence bacteria. We performed a literature review on this emerging therapy. MATERIALS AND METHODS: Literature review of bacterial interference to prevent symptomatic urinary tract infection in neurological population. RESULTS: Seven prospectives study including 3 randomized, double-blind and placebo controlled trial were analyzed. The neurological population was spinal cord injured in most cases. The bladder colonization was performed with 2 non-pathogen strains of Escherichia coli: HU 2117 and 83972. At 1 month, 38 to 83% of patients were colonized. Mean duration of colonization was 48.5 days to 12.3 months. All studies showed that colonization might reduce the number of urinary tract infections and is safe with absence of serious side effects. CONCLUSION: Bacterial interference is a promising alternative therapy for the prevention of recurrent symptomatic urinary tract infections in neurogenic patients. This therapy should have developments for a daily use practice and for a long-term efficacy.

The impact of migration on tuberculosis in the United States.

Due to greater exposure to Mycobacterium tuberculosis infection before migration, migrants moving to low-incidence settings can experience substantially higher tuberculosis (TB) rates than the native-born population. This review describes the impact of migration on TB epidemiology in the United States, and how the TB burden differs between US-born and non-US-born populations. The United States has a long history of receiving migrants from other parts of the world, and TB among non-US-born individuals now represents the majority of new TB cases. Based on an analysis of TB cases among individuals from the top 30 countries of origin in terms of non-US-born TB burden between 2003 and 2015, we describe how TB risks vary within the non-US-born population according to age, years since entry, entry year, and country of origin. Variation along each of these dimensions is associated with more than 10-fold differences in the risk of developing active TB, and this risk is also positively associated with TB incidence estimates for the country of origin and the composition of the migrant pool in the entry year. Approximately 87 000 lifetime TB cases are predicted for the non-US-born population resident in the United States in 2015, and 5800 lifetime cases for the population entering the United States in 2015.

Severe neutropenia revealing a rare presentation of dengue fever: a case report.

BACKGROUND: Arboviruses are a common cause of fever in the returned traveler often associated with leucopenia, especially lymphopenia and thrombocytopenia. Transient neutropenia has been described in a few cases of arboviruses. However, prolonged and severe neutropenia (<500/mm3) has rarely been reported in dengue fever, especially in the returned traveler in Europe. CASE PRESENTATION: A 26-year-old healthy female without any medical past history, flying back from Thailand, presented a transient fever with severe neutropenia (<500/mm3). Laboratory tests showed a mild hepatic cytolysis and thrombocytopenia, mimicking malaria or viral hepatitis. While she underwent protective isolation, NS1 antigen returned positive in favor of a dengue fever. Outcome was favorable without any antimicrobial therapy. CONCLUSION: Physicians should be wary of possible unusual presentation of dengue fever with prolonged neutropenia. Although such biological sign is more often associated with malaria or severe bacterial infection, it may be a sign of arbovirus.

Impact of an antimicrobial stewardship programme to optimize antimicrobial use for outpatients at an emergency department.

BACKGROUND: Antimicrobial stewardship programmes (ASPs) have been effective in optimizing antibiotic use for inpatients. However, an emergency department's fast-paced clinical setting can be challenging for a successful ASP. AIM: In April 2015, an ASP was implemented in our emergency department and we aimed to determine its impact on antimicrobial use for outpatients. METHODS: This was a single-centre study comparing the quality of antibiotic prescriptions between a one-year period before ASP implementation (November 2012 to October 2013) and a one-year period after its implementation (June 2015 to May 2016). For each period, antimicrobial prescriptions for all adult outpatients (hospitalized for <24h) were evaluated by an infectious disease specialist and an emergency department physician to assess compliance with local prescribing guidelines. Inappropriate prescriptions were then classified. FINDINGS: Before and after ASP, 34,671 and 35,925 consultations were registered at our emergency department, of which 25,470 and 26,208 were outpatients. Antimicrobials were prescribed in 769 (3.0%) and 580 (2.2%) consultations, respectively (P < 0.0001). There were 484 (62.9%) and 271 (46.7%) (P < 0.0001) instances of non-compliance with guidelines before and after ASP implementation. Non-compliance included unnecessary antimicrobial prescriptions, 197 (25.6%) vs 101 (17.4%) (P<0.0005); inappropriate spectrum, 108 (14.0%) vs 54 (9.3%) (P=0.008); excessive treatment duration, 87 (11.3%) vs 53 (9.1%) (P>0.05); and inappropriate choices, 11 (1.4%) vs 15 (2.6%) (P>0.05). CONCLUSION: The implementation of an ASP markedly decreased the number of unnecessary antimicrobial prescriptions, but had little impact on most other aspects of inappropriate prescribing.

Contribution of echocardiography in the diagnosis of definitive infective endocarditis: the infectious disease specialist's point of view.

In 1994, the original Duke criteria introduced the usefulness of echocardiography for the diagnosis of definitive infective endocarditis (IE). Recently, the European Society of Cardiology (ESC) highlighted the need of complementary imaging to support the diagnosis of embolic events and cardiac involvement when echocardiography findings are negative or doubtful. We decided to study the usefulness of transthoracic and transesophageal echocardiography (TTE/TEE) for the diagnosis of definitive IE in patients who already benefited from complementary investigations. A retrospective bicentric study was conducted among patients hospitalized for an IE (2006-2017). Modified Duke criteria were calculated for each patient before and after findings of TTE/TEE. Thereafter, patients were classified by the local task force into three groups: excluded, possible, and definitive IE. Overall, 86 episodes were studied. The median patient age was 72 years (18-95). Microorganisms involved were mostly Staphylococcus aureus (32.5%) and Streptococcus spp. (40.7%). The mortality rate was 17.4%. Before echocardiography, there were 3 excluded IE (3.5%), 51 possible IE (59.3%), and 32 definitive IE (37.2%). After echocardiography findings, we observed 62 definitive (72.1%) and 24 possible IE (27.9%) (p < 0.0001). Our cohort revealed that 19.8% of the definitive and possible IE had a normal echocardiography. The rate of septic emboli did not statistically differ between patients who had a contributive or a normal echocardiography (76.5% vs. 76.8%). TTE and TEE play a major role in the diagnosis of definitive IE, even if we consider findings of complementary imaging. Physicians should be wary that definitive IE may present with a non-contributive echocardiography, mentioned as normal.