Grow now, pay later: When should a bacterium go into debt?

Microbes grow in a wide variety of environments and must balance growth and stress resistance. Despite the prevalence of such trade-offs, understanding of their role in nonsteady environments is limited. In this study, we introduce a mathematical model of "growth debt," where microbes grow rapidly initially, paying later with slower growth or heightened mortality. We first compare our model to a classical chemostat experiment, validating our proposed dynamics and quantifying Escherichia coli's stress resistance dynamics. Extending the chemostat theory to include serial-dilution cultures, we derive phase diagrams for the persistence of "debtor" microbes. We find that debtors cannot coexist with nondebtors if "payment" is increased mortality but can coexist if it lowers enzyme affinity. Surprisingly, weak noise considerably extends the persistence of resistance elements, pertinent for antibiotic resistance management. Our microbial debt theory, broadly applicable across many environments, bridges the gap between chemostat and serial dilution systems.

New Genetic Variants of RUNX2 in Mexican Families Cause Cleidocranial Dysplasia.

Cleidocranial dysplasia (CCD) is an autosomal dominant skeletal dysplasia characterized by persistent open skull sutures with bulging calvaria, hypoplasia, or aplasia of clavicles permitting abnormal opposition of the shoulders; wide public symphysis; short middle phalanx of the fifth fingers; and vertebral, craniofacial, and dental anomalies. It is a rare disease, with a prevalence of 1-9/1,000,000, high penetrance, and variable expression. The gene responsible for CCD is the Runt-related transcription factor 2 (RUNX2) gene. We characterize the clinical, genetic, and bioinformatic results of four CCD cases: two cases within Mexican families with six affected members, nine asymptomatic individuals, and two sporadic cases with CCD, with one hundred healthy controls. Genomic DNA analyses of the RUNX2 gene were performed for Sanger sequencing. Bioinformatics tools were used to predict the function, stability, and structural changes of the mutated RUNX2 proteins. Three novel heterozygous mutations (c.651_652delTA; c.538_539delinsCA; c.662T>A) and a previously reported mutation (c.674G>A) were detected. In silico analysis showed that all mutations had functional, stability-related, and structural alterations in the RUNX2 protein. Our results show novel mutations that enrich the pool of RUNX2 gene mutations with CCD. Moreover, the proband 1 presented clinical data not previously reported that could represent an expanded phenotype of severe expression.

Chagasin from Trypanosoma cruzi as a molecular scaffold to express epitopes of TSA-1 as soluble recombinant chimeras.

Trypanosoma cruzi is the causative agent of Chagas disease, a global public health problem. New therapeutic drugs and biologics are needed. The TSA-1 recombinant protein of T. cruzi is one such promising antigen for developing a therapeutic vaccine. However, it is overexpressed in E. coli as inclusion bodies, requiring an additional refolding step. As an alternative, in this study, we propose the endogenous cysteine protease inhibitor chagasin as a molecular scaffold to generate chimeric proteins. These proteins will contain combinations of two of the five conserved epitopes (E1 to E5) of TSA-1 in the L4 and L6 chagasin loops. Twenty chimeras (Q1-Q20) were designed, and their solubility was predicted using bioinformatics tools. Nine chimeras with different degrees of solubility were selected and expressed in E. coli BL21 (DE3). Western blot assays with anti-6x-His and anti-chagasin antibodies confirmed the expression of soluble recombinant chimeras. Both theoretically and experimentally, the Q12 (E5-E3) chimera was the most soluble, and the Q20 (E4-E5) the most insoluble protein. Q4 (E5-E1) and Q8 (E5-E2) chimeras were classified as proteins with medium solubility that exhibited the highest yield in the soluble fraction. Notably, Q4 has a yield of 239 mg/L, well above the yield of recombinant chagasin (16.5 mg/L) expressed in a soluble form. The expression of the Q4 chimera was scaled up to a 7 L fermenter obtaining a yield of 490 mg/L. These data show that chagasin can serve as a molecular scaffold for the expression of TSA-1 epitopes in the form of soluble chimeras.

Trichomonas vaginalis Legumain-2, TvLEGU-2, Is an Immunogenic Cysteine Peptidase Expressed during Trichomonal Infection.

Trichomonas vaginalis is the causative agent of trichomoniasis, the most prevalent nonviral, neglected sexually transmitted disease worldwide. T. vaginalis has one of the largest degradomes among unicellular parasites. Cysteine peptidases (CPs) are the most abundant peptidases, constituting 50% of the degradome. Some CPs are virulence factors recognized by antibodies in trichomoniasis patient sera, and a few are found in vaginal secretions that show fluctuations in glucose concentrations during infection. The CPs of clan CD in T. vaginalis include 10 genes encoding legumain-like peptidases of the C13 family. TvLEGU-2 is one of them and has been identified in multiple proteomes, including the immunoproteome obtained with Tv (+) patient sera. Thus, our goals were to assess the effect of glucose on TvLEGU-2 expression, localization, and in vitro secretion and determine whether TvLEGU-2 is expressed during trichomonal infection. We performed qRT-PCR assays using parasites grown under different glucose conditions. We also generated a specific anti-TvLEGU-2 antibody against a synthetic peptide of the most divergent region of this CP and used it in Western blot (WB) and immunolocalization assays. Additionally, we cloned and expressed the tvlegu-2 gene (TVAG_385340), purified the recombinant TvLEGU-2 protein, and used it as an antigen for immunogenicity assays to test human sera from patients with vaginitis. Our results show that glucose does not affect tvlegu-2 expression but does affect localization in different parasite organelles, such as the plasma membrane, Golgi complex, hydrogenosomes, lysosomes, and secretion vesicles. TvLEGU-2 is secreted in vitro, is present in vaginal secretions, and is immunogenic in sera from Tv (+) patients, suggesting its relevance during trichomonal infection.

Ursolic Acid Induces Beneficial Changes in Skeletal Muscle mRNA Expression and Increases Exercise Participation and Performance in Dogs with Age-Related Muscle Atrophy.

Muscle atrophy and weakness are prevalent and debilitating conditions in dogs that cannot be reliably prevented or treated by current approaches. In non-canine species, the natural dietary compound ursolic acid inhibits molecular mechanisms of muscle atrophy, leading to improvements in muscle health. To begin to translate ursolic acid to canine health, we developed a novel ursolic acid dietary supplement for dogs and confirmed its safety and tolerability in dogs. We then conducted a randomized, placebo-controlled, proof-of-concept efficacy study in older beagles with age-related muscle atrophy, also known as sarcopenia. Animals received placebo or ursolic acid dietary supplements once a day for 60 days. To assess the study's primary outcome, we biopsied the quadriceps muscle and quantified atrophy-associated mRNA expression. Additionally, to determine whether the molecular effects of ursolic acid might have functional correlates consistent with improvements in muscle health, we assessed secondary outcomes of exercise participation and T-maze performance. Importantly, in canine skeletal muscle, ursolic acid inhibited numerous mRNA expression changes that are known to promote muscle atrophy and weakness. Furthermore, ursolic acid significantly improved exercise participation and T-maze performance. These findings identify ursolic acid as a natural dietary compound that inhibits molecular mechanisms of muscle atrophy and improves functional performance in dogs.

FRONTIER1: a partially randomized phase 2 study assessing the safety, pharmacokinetics, and pharmacodynamics of Mim8, a factor VIIIa mimetic.

BACKGROUND: Mim8 (denecimig) is a factor VIII (FVIII) mimetic bispecific antibody in development for the treatment of hemophilia. Data from the phase 1 part of FRONTIER1 (EudraCT: 2019-000465-20, NCT04204408, and NN7769-4513) suggested that Mim8 was well tolerated in healthy participants and exhibited pharmacokinetic (PK) properties consistent with dose proportionality. OBJECTIVES: The partially randomized, phase 2, multiple ascending dose (MAD) part of FRONTIER1 aimed to evaluate the safety, PK, pharmacodynamics (PD), and exploratory efficacy of Mim8 in participants with hemophilia A with or without FVIII inhibitors. METHODS: The MAD part of FRONTIER1 consisted of 42 participants, assigned to 5 cohorts, with participants in cohorts 3 and 4 randomized 1:1 to dosing weekly or every 4 weeks, respectively. Four of the 42 participants (9.5%) had FVIII inhibitors prior to study enrolment. The primary endpoint was treatment-emergent adverse events (TEAEs). PK and PD were evaluated by Mim8 plasma concentration and thrombin generation, respectively. Exploratory efficacy was assessed via the number of treated bleeds. Safety and PD parameters were also evaluated from an exploratory cohort treated with emicizumab. RESULTS: Mim8 was well tolerated, with 1 serious TEAE (anxiety-related chest pain) deemed unrelated to Mim8. There was no dose dependency on the number, causality, type, or severity of TEAEs. PK/PD properties supported weekly to monthly dosing approaches, and few participants experienced treated bleeds beyond the lowest dose cohort (1 in cohorts 2 and 3, and 3 in cohort 5). CONCLUSION: These data support the continued clinical development of Mim8, and FRONTIER1 has proceeded onto an extension phase.

Competition for shared resources increases dependence on initial population size during coalescence of gut microbial communities.

The long-term success of introduced populations depends on their initial size and ability to compete against existing residents, but it remains unclear how these factors collectively shape colonization. Here, we investigate how initial population (propagule) size and resource competition interact during community coalescence by systematically mixing eight pairs of in vitro microbial communities at ratios that vary over six orders of magnitude, and we compare our results to a neutral ecological model. Although the composition of the resulting co-cultures deviated substantially from neutral expectations, each co-culture contained species whose relative abundance depended on propagule size even after ~40 generations of growth. Using a consumer-resource model, we show that this dose-dependent colonization can arise when resident and introduced species have high niche overlap and consume shared resources at similar rates. This model predicts that propagule size will have larger, longer-lasting effects in diverse communities in which niche overlap is higher, and we experimentally confirm that strain isolates show stronger dose dependence when introduced into diverse communities than in pairwise co-culture. This work shows how neutral-like colonization dynamics can emerge from non-neutral resource competition and have lasting effects on the outcomes of community coalescence.

Management of post-ERCP duodenal perforations: experience at Hospital Juárez de México.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is an endoscopic study in which the duodenum is observed laterally, and the bile duct is instrumented. There are several indications and complications in the procedure. OBJECTIVE: To determine the incidence of duodenal perforations, using the Stapfer classification in the Hospital Juárez de Mexico over a period of 5 years, as well as the management implemented in such cases. METHOD: The study was carried out at the Hospital Juárez de Mexico of the Ministry of Health. All patients who underwent ERCP between January 1, 2017, to May 30, 2022 were included. RESULTS: 485 ERCP were performed in the study period. Incidence of 1.6% post-ERCP duodenal perforation. The average age of the subjects 56.37 years. In-hospital stay of post-ERCP perforations averaged 9.37 days. The time of the endoscopic study at the time of the surgical procedure is 10 h on average. CONCLUSIONS: Post-ERCP duodenal perforation is a complication that occurs with a low incidence, it tends to increase the number of days of in-hospital stay and increases morbimortality of patients; therefore, it is important to be always alert.

ANTECEDENTES: La colangiopancreatografía retrógrada endoscópica (CPRE) es un estudio endoscópico en el cual se observa lateralmente el duodeno y se instrumenta la vía biliar. Existen diversas indicaciones y complicaciones en el procedimiento. OBJETIVO: Determinar la incidencia de perforaciones duodenales utilizando la clasificación Stapfer para ubicación anatómica en el Hospital Juárez de México en un periodo de 5 años, así como el manejo implementado en dichos casos. MÉTODO: El estudio se realizó en el Hospital Juárez de México de la Secretaría de Salud. Se incluyeron todos los pacientes sometidos a CPRE entre el 1 de enero de 2017 y el 30 de mayo de 2022. RESULTADOS: Se realizaron 485 CPRE en el periodo de estudio. Hubo una incidencia del 1.6% de perforación duodenal post-CPRE. El promedio de edad de los sujetos fue de 56.37 años. La estancia hospitalaria de los pacientes con perforación post-CPRE fue en promedio de 9.37 días. El tiempo del estudio endoscópico al momento de realizar el procedimiento quirúrgico fue de 10 h en promedio. CONCLUSIONES: La perforación duodenal post-CPRE es una complicación que ocurre con una baja incidencia, suele aumentar los días de estancia intrahospitalaria y aumenta la morbimortalidad de los pacientes, y por ello es importante estar siempre alerta.

Enhancing Therapeutic Drug Monitoring in Inflammatory Bowel Disease: A Comparative Analysis of Rapid Point-of-Care Infliximab, Adalimumab and Anti-Drug Antibodies' Determination against ELISA.

The introduction of point-of-care (POC) assays into clinical practice in patients with inflammatory disease enables on-demand therapeutic decision making. The aim of this study was to compare the POC test Quantum blue (Bühlmann Laboratories) for infliximab (IFX), adalimumab (ADL), and its anti-drug antibodies with the traditional ELISA assay (Promonitor). A total of 200 serum samples were analyzed. Samples were classified into the following three different groups; sub-therapeutic range (IFX < 3 µg/mL and ADL < 5 µg/mL); therapeutic range (IFX: 3-7 µg/mL and ADL: 5-12 µg/mL) and supra-therapeutic range (IFX levels > 7 µg/mL and ADL levels > 12 µg/mL). Significant higher values were measured using the POC test (p < 0.001) for IFX results but no differences in ADL trough levels were observed (p = 0.3101). Spearman's correlation indicated a good correlation between the two assays (rs = 0.88 for ADL and rs = 0.93 for IFX), and McNemar's test revealed significant differences (p = 0.016) when classifying IFX samples between therapeutic and supra-therapeutic ranges but no significant differences were found among the other ranges for either IFX or ADL. These results show that we should be cautious when using these rapid measurement methods, and new targets should probably be defined for IFX when using this new analytical method.

Immunoglobin and T cell receptor repertoire changes induced by a prototype vaccine against Chagas disease in naïve rhesus macaques.

A vaccine against Trypanosoma cruzi, the agent of Chagas disease, would be an excellent additional tool for disease control. A recombinant vaccine based on Tc24 and TSA1 parasite antigens was found to be safe and immunogenic in naïve macaques. Here we performed a transcriptomic analysis of PBMC responses to vaccination, to shed light on the immunogenicity of this vaccine and guide the optimization of doses and formulation. RNA-sequencing analysis indicated a clear transcriptomic response of PBMCs from macaques after three vaccine doses, with the up-regulation of several immune cell activation pathways and a broad non-polarized immune profile. Analysis of the IgG repertoire showed that it had a rapid turnover with novel IgGs produced following each vaccine dose, while the TCR repertoire presented several persisting clones that were expanded after each vaccine dose. These data suggest that three vaccine doses may be needed for optimum immunogenecity and support the further evaluation of the protective efficacy of this vaccine.

Recurrent Mutation (p.Arg718Pro) in the COMP Gene with Clinical Heterogeneity of Pseudoachondroplasia.

Introduction: Pseudoachondroplasia (PSACH) and multiple epiphyseal dysplasia (MED) are allelic and caused by mutations in the COMP gene. Other mutations in the genes MMP13, AIFM1, B3GALT6, MATN3, COL9A1, COL9A2, COL9A3, and SLC26A2 have also been associated with evidence of dysplasia in the epiphysis, metaphysis, and spine. Case Presentation: We report on the first Mexican patient diagnosed with PSACH. The diagnosis was confirmed by identifying a recurrent heterozygous mutation c.2153G>C (p.Arg718Pro) in the COMP gene using whole-exome sequencing. Discussion: The anterior spindle-shaped vertebral bodies and severe short stature are not observed in patients carrying p.Arg718Pro, identifying another amino acid site associated with clinical heterogeneity. Reporting new cases with clinical heterogeneity in terms of phenotype plays a crucial role in understanding PSACH and MED pathogenesis. The most important aspect of this presentation is providing a new perspective on a recognized clinical scenario, thus setting the standard for better genetic counseling.

Bacterial DNA on the skin surface overrepresents the viable skin microbiome.

The skin microbiome provides vital contributions to human health. However, the spatial organization and viability of its bacterial components remain unclear. Here, we apply culturing, imaging, and molecular approaches to human and mouse skin samples, and find that the skin surface is colonized by fewer viable bacteria than predicted by bacterial DNA levels. Instead, viable skin-associated bacteria are predominantly located in hair follicles and other cutaneous invaginations. Furthermore, we show that the skin microbiome has a uniquely low fraction of viable bacteria compared to other human microbiome sites, indicating that most bacterial DNA on the skin surface is not associated with viable cells Additionally, a small number of bacterial families dominate each skin site and traditional sequencing methods overestimate both the richness and diversity of the skin microbiome. Finally, we performed an in vivo skin microbiome perturbation-recovery study using human volunteers. Bacterial 16S rRNA gene sequencing revealed that, while the skin microbiome is remarkably stable even in the wake of aggressive perturbation, repopulation of the skin surface is driven by the underlying viable population. Our findings help explain the dynamics of skin microbiome perturbation as bacterial DNA on the skin surface can be transiently perturbed but is replenished by a stable underlying viable population. These results address multiple outstanding questions in skin microbiome biology with significant implications for future efforts to study and manipulate it.

Guidelines for Qualifications of Neurodiagnostic Personnel: A Joint Position Statement of the American Clinical Neurophysiology Society, the American Association of Neuromuscular & Electrodiagnostic Medicine, the American Society of Neurophysiological Monitoring, and ASET The Neurodiagnostic Society.

The Guidelines for Qualifications of Neurodiagnostic Personnel (QNP) document has been created through the collaboration of the American Clinical Neurophysiology Society (ACNS), the American Society of Neurophysiological Monitoring (ASNM), the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM), and ASET The Neurodiagnostic Society (ASET). The quality of patient care is optimized when neurophysiological procedures are performed and interpreted by appropriately trained and qualified practitioners at every level. These societies recognize that neurodiagnostics is a large field with practitioners who have entered the field through a variety of training paths. This document suggests job titles, associated job responsibilities, and the recommended levels of education, certification, experience, and ongoing education appropriate for each job. This is important because of the growth and development of standardized training programs, board certifications, and continuing education in recent years. This document matches training, education, and credentials to the various tasks required for performing and interpreting neurodiagnostic procedures. This document does not intend to restrict the practice of those already working in neurodiagnostics. It represents recommendations of these societies with the understanding that federal, state, and local regulations, as well as individual hospital bylaws, supersede these recommendations. Because neurodiagnostics is a growing and dynamic field, the authors fully intend this document to change over time.

Excellent hemostatic control during cardiac surgery in a patient with hemophilia B treated with albutrepenonacog alfa (rIX-FP): A case report.

Key Clinical Message: In hemophilia patients undergoing cardiac surgery, ROTEM® and Quantra® viscoelastic tests are useful to monitor perioperative hemostatic status and a single dose of rIX-FP is safe and avoids any hemorrhagic or thrombotic complication. Abstract: Cardiac surgery poses a high hemostatic risk in patients with hemophilia. We present the first case of an adult patient with hemophilia B on treatment with albutrepenonacog alfa (rIX-FP) who underwent surgery for acute coronary syndrome. Treatment with rIX-FP made it possible to perform the surgery safely.

Usefulness of the H-Reflex for Intraoperative Monitoring of Thoracoabdominal Aneurysms.

PURPOSE: Intraoperative neurophysiologic monitoring in thoracoabdominal aneurysms (TAAA) is essential to avoid intraoperative spinal cord injury). Motor and somatosensory evoked potentials may be considered intraoperative tools for detecting spinal cord injury. H-reflex is a well-known neurophysiologic technique to evaluate L5-S1 root. Current evidence supports the observation that H-reflex changes may occur with spinal cord damage as high as the cervical level. This study aimed to evaluate the usefulness of the H-reflex in these surgeries. METHODS: The use of intraoperative H-reflex in TAAA monitoring was evaluated in 12 patients undergoing open or endovascular repair of TAAA for a period of four years (2016-2020) using somatosensory evoked potentials (SSEPs) and transcranial motor evoked potentials (TcMEPs) and bilateral H-reflex. RESULTS: Six neurophysiologic alarms were recorded in five of the 12 patients. Summarizing the neurophysiologic changes of our series, we considered a peripheral change when we detected a unilateral loss of SSEPs, TcMEPs, and H-reflex. Instead, we assumed a central change when we detected a unilateral or bilateral loss of TcMEPs and H-reflex with normal SSEPs, which we considered a sign of spinal cord ischemia. Interestingly H-reflex always changed significantly in combination with TcMEPs in the same fashion. CONCLUSIONS: According to our series, H-reflex can detect intraoperative changes with the same sensitivity as TcMEPs in TAAA surgeries. With the support of other techniques, it can be useful to localize the origin of the lesion (peripheral or central spinal cord), to help in surgical decision-making to avoid postoperative neurologic damage. Based on our results, we recommend the systematic use of H-reflex in TAAA surgeries.

Duration of antibiotic therapy among paediatricians: A national survey of current clinical practice in Spain.

OBJECTIVES: Appropriate duration of antibiotic treatment is a key principle to reduce the emergence of bacterial resistance and antibiotic harm. The aim of this study was to document current clinical practice among Spanish paediatricians in terms of the duration of antibiotic therapy in both inpatient and outpatient settings, mapping the difference between practice and guidelines, and thus identifying opportunities to improve practice. METHODS: A national exploratory work survey was distributed in 2020 as a questionnaire about seven main infectious syndromes in children: genitourinary; skin and soft tissue; osteoarticular; ear, nose and throat; pneumonia; central nervous system; and bacteraemia. The answers were contrasted with current recommendations regarding the duration of antibiotic therapy. Demographic analysis was also performed. RESULTS: The survey was completed by 992 paediatricians in Spain, representing 9.5% of paediatricians working in the Spanish national health system. Hospital care clinicians accounted for 42.7% (6662/15590) of responses. The antibiotic duration used in practice was longer than recommended in 40.8% (6359/15590) of responses, and shorter than recommended in 16% (1705/10654) of responses. Only 25% (249/992) and 23% (229/992) of respondents indicated that they would prescribe antibiotics for the recommended treatment duration for lower urinary tract infection and community-acquired pneumonia (AI evidence). Among severe hospital-managed infections, a tendency towards longer courses of antibiotics was found for non-complicated meningococcal infections and non-complicated pneumococcal, Gram-negative and S. aureus bacteraemia. CONCLUSIONS: A noteworthy tendency towards prescribing antibiotics for longer than recommended among paediatricians was evidenced in this nationwide study, highlighting a wide range of opportunities for potential improvement.

Guidelines for Qualifications of Neurodiagnostic Personnel: A Joint Position Statement of the American Clinical Neurophysiology Society, the American Association of Neuromuscular & Electrodiagnostic Medicine, the American Society of Neurophysiological Monitoring, and ASET - The Neurodiagnostic Society.

The Guidelines for Qualifications of Neurodiagnostic Personnel (QNP) document has been created through the collaboration of the American Clinical Neurophysiology Society (ACNS), the American Society of Neurophysiological Monitoring (ASNM), the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM), and ASET - The Neurodiagnostic Society (ASET). The quality of patient care is optimized when neurophysiological procedures are performed and interpreted by appropriately trained and qualified practitioners at every level. These Societies recognize that Neurodiagnostics is a large field with practitioners who have entered the field through a variety of training paths. This document suggests job titles, associated job responsibilities, and the recommended levels of education, certification, experience, and ongoing education appropriate for each job. This is important because of the growth and development of standardized training programs, board certifications, and continuing education in recent years. This document matches training, education, and credentials to the various tasks required for performing and interpreting Neurodiagnostic procedures. This document does not intend to restrict the practice of those already working in Neurodiagnostics. It represents recommendations of these Societies with the understanding that federal, state, and local regulations, as well as individual hospital bylaws, supersede these recommendations. As Neurodiagnostics is a growing and dynamic field, we fully intend this document to change over time.