ABSTRACT
BACKGROUND: In the United States in 2017, there were an estimated 903,745 hospitalizations involving mechanical ventilation (MV). Complications from ventilation can result in longer hospital stays, increased risk of disability, and increased healthcare costs. It has been hypothesized that electrically pacing the diaphragm by phrenic nerve stimulation during mechanical ventilation may minimize or reverse diaphragm dysfunction, resulting in faster weaning. METHODS: The ReInvigorate Trial is a prospective, multicenter, randomized, controlled clinical trial evaluating the safety and efficacy of Stimdia's pdSTIM System for facilitating weaning from MV. The pdSTIM system employs percutaneously placed multipolar electrodes to stimulate the cervical phrenic nerves and activate contraction of the diaphragm bilaterally. Patients who were on mechanical ventilation for at least 96 h and who failed at least one weaning attempt were considered for enrollment in the study. The primary efficacy endpoint was the time to successful liberation from mechanical ventilation (treatment vs. control). Secondary endpoints will include the rapid shallow breathing index and other physiological and system characteristics. Safety will be summarized for both primary and additional analyses. All endpoints will be evaluated at 30 days or at the time of removal of mechanical ventilation, whichever is first. DISCUSSION: This pivotal study is being conducted under an investigational device exception with the U.S. Food and Drug Administration. The technology being studied could provide a first-of-kind therapy for difficult-to-wean patients on mechanical ventilation in an intensive care unit setting. TRIAL REGISTRATION: Clinicaltrials.gov, NCT05998018 , registered August 2023.
Subject(s)
Diaphragm , Multicenter Studies as Topic , Phrenic Nerve , Randomized Controlled Trials as Topic , Ventilator Weaning , Humans , Ventilator Weaning/methods , Diaphragm/innervation , Phrenic Nerve/physiology , Prospective Studies , Time Factors , Treatment Outcome , Respiration, Artificial/adverse effects , Respiration, Artificial/methods , Electric Stimulation Therapy/methods , Electric Stimulation Therapy/adverse effects , Electric Stimulation Therapy/instrumentationABSTRACT
Disorders of consciousness represent altered mental status at its most severe, comprising a continuum between coma, the vegetative state/unresponsive wakefulness syndrome, the minimally conscious state, and emergence from the minimally conscious state. Patients often transition between these levels throughout their recovery, and determining a patient's current level can be challenging, particularly in the acute care setting. Although healthcare providers have classically relied on a bedside neurological exam or the Glasgow Coma Scale to aid with assessment of consciousness, studies have identified multiple limitations of doing so. Neurobehavioral assessment measures, such as the Coma Recovery Scale-Revised, have been developed to address these shortcomings. Each behavioral metric has strengths as well as weaknesses when applied in the acute care setting. In this review, we appraise common assessment approaches, outline alternative measures for fine-tuning these assessments in the acute care setting, and highlight strategies for implementing these practices in an interdisciplinary manner.
ABSTRACT
Candida glabrata (also called Nakaseomyces glabratus) is an opportunistic pathogen that can resist common antifungals and rapidly acquire multidrug resistance. A large amount of genetic variation exists between isolates, which complicates generalizations. Portable Tn-seq methods can efficiently provide genome-wide information on strain differences and genetic mechanisms. Using the Hermes transposon, the CBS138 reference strain and a commonly studied derivative termed 2001 were subjected to Tn-seq in control conditions and after exposure to varying doses of the clinical antifungal micafungin. The approach revealed large differences between these strains, including a 131 kb tandem duplication and a variety of fitness differences. Additionally, both strains exhibited up to 1000-fold increased transposon accessibility in subtelomeric regions relative to the BG2 strain, indicative of open subtelomeric chromatin in these isolates and large epigenetic variation within the species. Unexpectedly, the Pdr1 transcription factor conferred resistance to micafungin through targets other than CDR1. Other micafungin resistance pathways were also revealed including mannosyltransferase activity and biosynthesis of the lipid precursor sphingosine, the inhibition of which by SDZ 90-215 and myriocin enhanced the potency of micafungin in vitro. These findings provide insights into complexity of the C. glabrata species as well as strategies for improving antifungal efficacy.
ABSTRACT
Severe trauma can induce systemic inflammation but also immunosuppression, which makes understanding the immune response of trauma patients critical for therapeutic development and treatment approaches. By evaluating the levels of 59 proteins in the plasma of 50 healthy volunteers and 1000 trauma patients across five trauma centers in the United States, we identified 6 novel changes in immune proteins after traumatic injury and further new variations by sex, age, trauma type, comorbidities, and developed a new equation for prediction of patient survival. Blood was collected at the time of arrival at Level 1 trauma centers and patients were stratified based on trauma level, tissues injured, and injury types. Trauma patients had significantly upregulated proteins associated with immune activation (IL-23, MIP-5), immunosuppression (IL-10) and pleiotropic cytokines (IL-29, IL-6). A high ratio of IL-29 to IL-10 was identified as a new predictor of survival in less severe patients with ROC area of 0.933. Combining machine learning with statistical modeling we developed an equation ("VIPER") that could predict survival with ROC 0.966 in less severe patients and 0.8873 for all patients from a five analyte panel (IL-6, VEGF-A, IL-21, IL-29, and IL-10). Furthermore, we also identified three increased proteins (MIF, TRAIL, IL-29) and three decreased proteins (IL-7, TPO, IL-8) that were the most important in distinguishing a trauma blood profile. Biologic sex altered phenotype with IL-8 and MIF being lower in healthy women, but higher in female trauma patients when compared to male counterparts. This work identifies new responses to injury that may influence systemic immune dysfunction, serving as targets for therapeutics and immediate clinical benefit in identifying at-risk patients.
ABSTRACT
C. glabrata is an opportunistic pathogen that can resist common antifungals and rapidly acquire multidrug resistance. A large amount of genetic variation exists between isolates, which complicates generalizations. Portable Tn-seq methods can efficiently provide genome-wide information on strain differences and genetic mechanisms. Using the Hermes transposon, the CBS138 reference strain and a commonly studied derivative termed 2001 were subjected to Tn-seq in control conditions and after exposure to varying doses of the clinical antifungal micafungin. The approach revealed large differences between these strains, including a 131 kb tandem duplication and a variety of fitness differences. Additionally, both strains exhibited up to 1000-fold increased transposon accessibility in subtelomeric regions relative to the BG2 strain, indicative of open subtelomeric chromatin in these isolates and large epigenetic variation within the species. Unexpectedly, the Pdr1 transcription factor conferred resistance to micafungin through targets other than CDR1 . Other micafungin resistance pathways were also revealed including mannosyltransferase activity and biosynthesis of the lipid precursor sphingosine, the drugging of which by SDZ 90-215 or myriocin enhanced the potency of micafungin in vitro . These findings provide insights into complexity of the C. glabrata species as well as strategies for improving antifungal efficacy. Summary: Candida glabrata is an emerging pathogen with large genetic diversity and genome plasticity. The type strain CBS138 and a laboratory derivative were mutagenized with the Hermes transposon and profiled using Tn-seq. Numerous genes that regulate innate and acquired resistance to an important clinical antifungal were uncovered, including a pleiotropic drug resistance gene (PDR1) and a duplication of part of one chromosome. Compounds that target PDR1 and other genes may augment the potency of existing antifungals.
ABSTRACT
BACKGROUND: Surgical stabilization of rib fractures (SSRF) improves outcomes in chest wall trauma. Geriatric patients are particularly vulnerable to poor outcomes; yet, this population is often excluded from SSRF studies. Further delineating patient outcomes by age is necessary to optimize care for the aging trauma population. METHODS: A retrospective cohort study was conducted examining outcomes among patients aged 40+ for whom an SSRF consult was placed between 2017 and 2022 at a level 1 trauma center. Patients were categorized into geriatric (65+) and adult (40-64), as well as 80 years and older (80+) and 79 and younger (40-79). Patient outcomes were assessed comparing non-operative and operative management of chest wall trauma. Propensity matched analysis was performed to evaluate mortality differences between adult and geriatric patients who did and did not undergo SSRF. RESULTS: A total of 543 patients had an SSRF consult. Of these, 227 were 65+, and 73 were 80+. A total of 129 patients underwent SSRF (24 %). The percentage of patients undergoing SSRF did not vary between 40 and 64 and 65+ (23.7 % and 23.6 %, respectively, p = 0.97) or 40-79 and 80+ (24.0 vs 21.9, p = 0.69). Patients undergoing SSRF had higher chest injury burden and were more likely to require mechanical ventilation and ICU level care on admission. Overall, in-hospital mortality rate was 4.6 %. Among patients who underwent SSRF, mortality rate did not significantly differ between 65+ and 40-64 (7.8% vs 2.7 %, p = 0.18) or 80+ and 40-79 (6.3% vs 4.6 %, p = 0.77). This remained true in propensity matched analysis. CONCLUSION: Geriatric and octogenarian patients with rib fractures underwent SSRF at similar rates and achieved equivalent outcomes to their younger counterparts. SSRF did not differentially affect mortality outcomes based on age group in propensity matched analysis. SSRF is safe for geriatric patients including octogenarians.
Subject(s)
Propensity Score , Rib Fractures , Trauma Centers , Humans , Rib Fractures/surgery , Rib Fractures/mortality , Female , Male , Retrospective Studies , Aged , Aged, 80 and over , Middle Aged , Treatment Outcome , Adult , Age Factors , Hospital Mortality , Fracture Fixation, Internal/methods , Thoracic Injuries/surgery , Thoracic Injuries/mortalityABSTRACT
Liebold et al. recently revealed how the identity of dying cells drives distinct changes to the macrophages which engulf and clear them, a process known as efferocytosis. During infection with the helminth Schistosoma mansoni, liver macrophages recapitulate these phenotypes, mediated by Axl/MerTK receptors and regulating egg burdens.
Subject(s)
Macrophages , Phagocytosis , Schistosoma mansoni , Animals , Macrophages/immunology , Macrophages/parasitology , Schistosoma mansoni/physiology , Schistosoma mansoni/immunology , Schistosomiasis mansoni/immunology , Schistosomiasis mansoni/parasitology , Receptor Protein-Tyrosine Kinases/metabolism , Receptor Protein-Tyrosine Kinases/immunology , Humans , Liver/parasitology , Liver/immunology , Axl Receptor Tyrosine Kinase , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins/genetics , c-Mer Tyrosine Kinase/metabolism , c-Mer Tyrosine Kinase/physiology , EfferocytosisABSTRACT
ABSTRACT: Providers are charged with responsibility to maintain their own health and wellness; however, well-being is multifactorial and the construct lacks clarity. In the current state of health care, burnout is on the rise with increasing demands for clinical productivity and strained system resources. The health care industry has recognized wellness's patient safety and financial impact, recently applying research and resources to identify sustainable solutions. We reviewed the wellness literature with a focus on systems to provide a framework for consensus building for a quality acute care surgery system. Our review revealed several areas within system wellness for consideration: (1) provider wellness, (2) culture of safety, (3) learning health systems, and (4) organizational perspectives. We provide specific system recommendations for the acute care surgery practice to preserve our workforce by creating a system that works for its providers.
Subject(s)
Burnout, Professional , Humans , Burnout, Professional/prevention & control , Organizational Culture , Traumatology , United States , Health Promotion , WhiteABSTRACT
BACKGROUND: The Joint Commission reports that at least half of communication breakdowns occur during handovers or transitions of care. There is no consensus on how best to approach the transfer of care within acute care surgery (ACS). We conduct a systematic review and meta-analysis of the current data on handoffs and transitions of care in ACS patients and evaluate the impact of standardization and formalized communication processes. METHODS: Clinically relevant questions regarding handoffs and transitions of care with clearly defined patient Population(s), Intervention(s), Comparison(s), and appropriately selected Outcomes were determined. These centered around specific transitions of care within the setting of ACS, specifically perioperative interactions, emergency medical services and trauma team interactions, and intra/interfloor and intensive care unit (ICU) interactions. A systematic literature review and meta-analysis were conducted using the Grading of Recommendations Assessment, Development, and Evaluation methodology. RESULTS: A total of 10 studies were identified for analysis. These included 5,113 patients in the standardized handoff group and 5,293 in the current process group. Standardized handoffs reduced handover errors for perioperative interactions and preventable adverse events for intra/interfloor and ICU interactions. There were insufficient data to evaluate outcomes of clinical complications and medical errors. CONCLUSION: We conditionally recommend a standardized handoff in the field of ACS, including perioperative interactions, emergency medical services and trauma team interactions, and intra/interfloor and ICU interactions. LEVEL OF EVIDENCE: Systematic Review/Meta-analysis; Level III.
Subject(s)
Patient Handoff , Humans , Patient Care Team/organization & administration , Patient Care Team/standards , Patient Handoff/standards , Patient Handoff/organization & administration , Patient Transfer/standards , Wounds and Injuries/surgery , Wounds and Injuries/therapyABSTRACT
Demyelination in the central nervous system (CNS) resulting from injury or disease can cause loss of nerve function and paralysis. Cell therapies intended to promote remyelination of axons are a promising avenue of treatment, with mesenchymal stromal cells (MSCs) a prominent candidate. We have previously demonstrated that MSCs derived from human olfactory mucosa (hOM-MSCs) promote myelination to a greater extent than bone marrow-derived MSCs (hBM-MSCs). However, hOM-MSCs were developed using methods and materials that were not good manufacturing practice (GMP)-compliant. Before considering these cells for clinical use, it is necessary to develop a method for their isolation and expansion that is readily adaptable to a GMP-compliant environment. We demonstrate here that hOM-MSCs can be derived without enzymatic tissue digestion or cell sorting and without culture antibiotics. They grow readily in GMP-compliant media and express typical MSC surface markers. They robustly produce CXCL12 (a key secretory factor in promoting myelination) and are pro-myelinating in in vitro rodent CNS cultures. GMP-compliant hOM-MSCs are comparable in this respect to those grown in non-GMP conditions. However, when assessed in an in vivo model of demyelinating disease (experimental autoimmune encephalitis, EAE), they do not significantly improve disease scores compared with controls, indicating further pre-clinical evaluation is necessary before their advancement to clinical trials.
Subject(s)
Anti-Bacterial Agents , Mesenchymal Stem Cells , Humans , Culture Techniques , Axons , Biological TransportABSTRACT
The protein phosphatase calcineurin is vital for the virulence of the opportunistic fungal pathogen Candida glabrata. The host-induced stresses that activate calcineurin signaling are unknown, as are the targets of calcineurin relevant to virulence. To potentially shed light on these processes, millions of transposon insertion mutants throughout the genome of C. glabrata were profiled en masse for fitness defects in the presence of FK506, a specific inhibitor of calcineurin. Eighty-seven specific gene deficiencies depended on calcineurin signaling for full viability in vitro both in wild-type and pdr1∆ null strains lacking pleiotropic drug resistance. Three genes involved in cell wall biosynthesis (FKS1, DCW1, FLC1) possess co-essential paralogs whose expression depended on calcineurin and Crz1 in response to micafungin, a clinical antifungal that interferes with cell wall biogenesis. Interestingly, 80% of the FK506-sensitive mutants were deficient in different aspects of vesicular trafficking, such as endocytosis, exocytosis, sorting, and biogenesis of secretory proteins in the endoplasmic reticulum (ER). In response to the experimental antifungal manogepix that blocks GPI-anchor biosynthesis in the ER, calcineurin signaling increased and strongly prevented cell death independent of Crz1, one of its major targets. Comparisons between manogepix, micafungin, and the ER-stressing tunicamycin reveal a correlation between the degree of calcineurin signaling and the degree of cell survival. These findings suggest that calcineurin plays major roles in mitigating stresses of vesicular trafficking. Such stresses may arise during host infection and in response to antifungal therapies.IMPORTANCECalcineurin plays critical roles in the virulence of most pathogenic fungi. This study sheds light on those roles in the opportunistic pathogen Candida glabrata using a genome-wide analysis in vitro. The findings could lead to antifungal developments that also avoid immunosuppression.
Subject(s)
Aminopyridines , Antifungal Agents , Candidiasis , Isoxazoles , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Candida glabrata/physiology , Micafungin/therapeutic use , Candidiasis/microbiology , Calcineurin/genetics , Tacrolimus/pharmacology , Tacrolimus/therapeutic use , Fungal Proteins/genetics , Fungal Proteins/metabolismABSTRACT
Early surgical stabilization of rib fracture (SSRF) improves outcomes in patients with flail physiology and severely displaced fractures. We present two cases of patients with severe chest injury and large flail segment who underwent SSRF while on veno-venous extracorporeal membrane oxygenation (VV-ECMO). The patients developed respiratory failure within 24 hours of admission requiring VV-ECMO. The extent of their chest wall injury limited pulmonary mechanics prohibiting transition off VV-ECMO. Therefore, SSRF was performed on hospital days 2 and 3 and while on VV-ECMO support. Stabilizing the chest wall allowed for improved ventilation and successful decannulation from VV-ECMO on postoperative days 3 and 4. Ultimately, both achieved a functional recovery and were discharged home. These cases demonstrate a unique thoracic damage control strategy wherein SSRF is performed while on VV-ECMO. Improving chest stability and pulmonary mechanics with SSRF allowed for safe transition off VV-ECMO and achieved a favorable long-term outcome.
Subject(s)
Extracorporeal Membrane Oxygenation , Flail Chest , Rib Fractures , Thoracic Injuries , Wounds, Nonpenetrating , Humans , Rib Fractures/complications , Rib Fractures/surgery , Wounds, Nonpenetrating/complications , Wounds, Nonpenetrating/surgery , Flail Chest/etiology , Flail Chest/surgery , Retrospective StudiesABSTRACT
The murine helminth parasite Heligmosomoides polygyrus expresses a family of modular proteins which, replicating the functional activity of the immunomodulatory cytokine TGF-ß, have been named TGM (TGF-ß Μimic). Multiple domains bind to different receptors, including TGF-ß receptors TßRI (ALK5) and TßRII through domains 1-3, and prototypic family member TGM1 binds the cell surface co-receptor CD44 through domains 4-5. This allows TGM1 to induce T lymphocyte Foxp3 expression, characteristic of regulatory (Treg) cells, and to activate a range of TGF-ß-responsive cell types. In contrast, a related protein, TGM4, targets a much more restricted cell repertoire, primarily acting on myeloid cells, with less potent effects on T cells and lacking activity on other TGF-ß-responsive cell types. TGM4 binds avidly to myeloid cells by flow cytometry, and can outcompete TGM1 for cell binding. Analysis of receptor binding in comparison to TGM1 reveals a 10-fold higher affinity than TGM1 for TGFßR-I (TßRI), but a 100-fold lower affinity for TßRII through Domain 3. Consequently, TGM4 is more dependent on co-receptor binding; in addition to CD44, TGM4 also engages CD49d (Itga4) through Domains 1-3, as well as CD206 and Neuropilin-1 through Domains 4 and 5. TGM4 was found to effectively modulate macrophage populations, inhibiting lipopolysaccharide-driven inflammatory cytokine production and boosting interleukin (IL)-4-stimulated responses such as Arginase-1 in vitro and in vivo. These results reveal that the modular nature of TGMs has allowed the fine tuning of the binding affinities of the TßR- and co-receptor binding domains to establish cell specificity for TGF-ß signalling in a manner that cannot be attained by the mammalian cytokine.
ABSTRACT
BACKGROUND: End-tidal carbon dioxide (ETCO2) has previously shown promise as a predictor of shock severity and mortality in trauma. ETCO2 monitoring is non-invasive, real-time, and readily available in prehospital settings, but the temporal relationship of ETCO2 to systemic oxygen transport has not been thoroughly investigated in the context of hemorrhagic shock. METHODS: A validated porcine model of hemorrhagic shock and resuscitation was used in male Yorkshire swine (N â= â7). Both ETCO2 and central venous oxygenation (SCVO2) were monitored and recorded continuously in addition to other traditional hemodynamic variables. RESULTS: Linear regression analysis showed that ETCO2 was associated with ScvO2 both throughout the experiment (ß â= â1.783, 95% confidence interval (CI) [1.552-2.014], p â< â0.001) and during the period of most rapid hemorrhage (ß â= â4.896, 95% CI [2.416-7.377], p â< â0.001) when there was a marked decrease in ETCO2. CONCLUSIONS: ETCO2 and ScvO2 were closely associated during rapid hemorrhage and continued to be temporally associated throughout shock and resuscitation.
Subject(s)
Shock, Hemorrhagic , Male , Swine , Animals , Shock, Hemorrhagic/therapy , Carbon Dioxide , Resuscitation , Hemorrhage , HemodynamicsABSTRACT
Long-lived parasites evade host immunity through highly evolved molecular strategies. The murine intestinal helminth, Heligmosomoides polygyrus, down-modulates the host immune system through release of an immunosuppressive TGF-ß mimic, TGM1, which is a divergent member of the CCP (Sushi) protein family. TGM1 comprises 5 domains, of which domains 1-3 (D1/2/3) bind mammalian TGF-ß receptors, acting on T cells to induce Foxp3+ regulatory T cells; however, the roles of domains 4 and 5 (D4/5) remain unknown. We noted that truncated TGM1, lacking D4/5, showed reduced potency. Combination of D1/2/3 and D4/5 as separate proteins did not alter potency, suggesting that a physical linkage is required and that these domains do not deliver an independent signal. Coprecipitation from cells treated with biotinylated D4/5, followed by mass spectrometry, identified the cell surface protein CD44 as a coreceptor for TGM1. Both full-length and D4/5 bound strongly to a range of primary cells and cell lines, to a greater degree than D1/2/3 alone, although some cell lines did not respond to TGM1. Ectopic expression of CD44 in nonresponding cells conferred responsiveness, while genetic depletion of CD44 abolished enhancement by D4/5 and ablated the ability of full-length TGM1 to bind to cell surfaces. Moreover, CD44-deficient T cells showed attenuated induction of Foxp3 by full-length TGM1, to levels similar to those induced by D1/2/3. Hence, a parasite protein known to bind two host cytokine receptor subunits has evolved a third receptor specificity, which serves to raise the avidity and cell type-specific potency of TGF-ß signaling in mammalian cells.
Subject(s)
Parasites , Animals , Mice , T-Lymphocytes, Regulatory , Signal Transduction , Transforming Growth Factor beta , Forkhead Transcription Factors , MammalsABSTRACT
Background: Quality improvement is a cornerstone for any verified trauma center. Conducting effective quality and performance improvement, however, remains a challenge. In this study, we sought to better explore the landscape and challenges facing the members of the Eastern Association for the Surgery of Trauma (EAST) through a survey. Methods: A survey was designed by the EAST Quality Patient Safety and Outcomes Committee. It was reviewed by the EAST Research and Scholarship Committee and then distributed to 2511 EAST members. The questions were designed to understand the frequency, content, and perceptions surrounding quality improvement processes. Results: There were 151 respondents of the 2511 surveys sent (6.0%). The majority were trauma faculty (55%) or trauma medical directors (TMDs) (37%) at American College of Surgeons level I (62%) or II (17%) trauma centers. We found a wide variety of resources being used across hospitals with the majority of cases being identified by a TMD or attending (81%) for a multidisciplinary peer review (70.2%). There was a statistically significant difference in the perception of the effectiveness of the quality improvement process with TMDs being more likely to describe their process as moderately or very effective compared with their peers (77.5% vs. 57.7%, p=0.026). The 'Just Culture' model appeared to have a positive effect on the process improvement environment, with providers less likely to report a non-conducive environment (10.9% vs. 27.6%, p=0.012) and less feelings of assigning blame (3.1% vs. 13.8%, p=0.026). Conclusion: Case review remains an essential but challenging process. Our survey reveals a need to continue to advocate for appropriate time and resources to conduct strong quality improvement processes. Level of evidence: Epidemiological study, level III.
ABSTRACT
Candida glabrata is a prominent opportunistic fungal pathogen of humans. The increasing incidence of C. glabrata infections is attributed to both innate and acquired resistance to antifungals. Previous studies suggest the transcription factor Pdr1 and several target genes encoding ABC transporters are critical elements of pleiotropic defense against azoles and other antifungals. This study utilizes Hermes transposon insertion profiling to investigate Pdr1-independent and Pdr1-dependent mechanisms that alter susceptibility to the frontline antifungal fluconazole. Several new genes were found to alter fluconazole susceptibility independent of Pdr1 (CYB5, SSK1, SSK2, HOG1, TRP1). A bZIP transcription repressor of mitochondrial function (CIN5) positively regulated Pdr1 while hundreds of genes encoding mitochondrial proteins were confirmed as negative regulators of Pdr1. The antibiotic oligomycin activated Pdr1 and antagonized fluconazole efficacy likely by interfering with mitochondrial processes in C. glabrata. Unexpectedly, disruption of many 60S ribosomal proteins also activated Pdr1, thus mimicking the effects of the mRNA translation inhibitors. Cycloheximide failed to fully activate Pdr1 in a cycloheximide-resistant Rpl28-Q38E mutant. Similarly, fluconazole failed to fully activate Pdr1 in a strain expressing a low-affinity variant of Erg11. Fluconazole activated Pdr1 with very slow kinetics that correlated with the delayed onset of cellular stress. These findings are inconsistent with the idea that Pdr1 directly senses xenobiotics and support an alternative hypothesis where Pdr1 senses cellular stresses that arise only after engagement of xenobiotics with their targets. IMPORTANCE Candida glabrata is an opportunistic pathogenic yeast that causes discomfort and death. Its incidence has been increasing because of natural defenses to our common antifungal medications. This study explores the entire genome for impacts on resistance to fluconazole. We find several new and unexpected genes can impact susceptibility to fluconazole. Several antibiotics can also alter the efficacy of fluconazole. Most importantly, we find that Pdr1-a key determinant of fluconazole resistance-is not regulated directly through binding of fluconazole and instead is regulated indirectly by sensing the cellular stresses caused by fluconazole blockage of sterol biosynthesis. This new understanding of drug resistance mechanisms could improve the outcomes of current antifungals and accelerate the development of novel therapeutics.
Subject(s)
Antifungal Agents , Fluconazole , Humans , Antifungal Agents/pharmacology , Antifungal Agents/metabolism , Candida glabrata/genetics , Cycloheximide/metabolism , Cycloheximide/pharmacology , Drug Resistance, Fungal/genetics , Fluconazole/pharmacology , Fungal Proteins/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Xenobiotics/metabolism , Xenobiotics/pharmacologyABSTRACT
OBJECTIVE: This study aimed to determine whether lower extremity fracture fixation technique and timing (≤24 vs. >24 hours) impact neurologic outcomes in TBI patients. METHODS: A prospective observational study was conducted across 30 trauma centers. Inclusion criteria were age 18 years and older, head Abbreviated Injury Scale (AIS) score of >2, and a diaphyseal femur or tibia fracture requiring external fixation (Ex-Fix), intramedullary nailing (IMN), or open reduction and internal fixation (ORIF). The analysis was conducted using analysis of variamce, Kruskal-Wallis, and multivariable regression models. Neurologic outcomes were measured by discharge Ranchos Los Amigos Revised Scale (RLAS-R). RESULTS: Of the 520 patients enrolled, 358 underwent Ex-Fix, IMN, or ORIF as definitive management. Head AIS was similar among cohorts. The Ex-Fix group experienced more severe lower extremity injuries (AIS score, 4-5) compared with the IMN group (16% vs. 3%, p = 0.01) but not the ORIF group (16% vs. 6%, p = 0.1). Time to operative intervention varied between the cohorts with the longest time to intervention for the IMN group (median hours: Ex-Fix, 15 [8-24] vs. ORIF, 26 [12-85] vs. IMN, 31 [12-70]; p < 0.001). The discharge RLAS-R score distribution was similar across the groups. After adjusting for confounders, neither method nor timing of lower extremity fixation influenced the discharge RLAS-R. Instead, increasing age and head AIS score were associated with a lower discharge RLAS-R score (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.002-1.03 and OR, 2.37; 95% CI, 1.75-3.22), and a higher Glasgow Coma Scale motor score on admission (OR, 0.84; 95% CI, 0.73-0.97) was associated with higher RLAS-R score at discharge. CONCLUSION: Neurologic outcomes in TBI are impacted by severity of the head injury and not the fracture fixation technique or timing. Therefore, the strategy of definitive fixation of lower extremity fractures should be dictated by patient physiology and the anatomy of the injured extremity and not by the concern for worsening neurologic outcomes in TBI patients. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level III.
Subject(s)
Brain Injuries, Traumatic , Fracture Fixation, Intramedullary , Leg Injuries , Tibial Fractures , Humans , Adolescent , Fracture Fixation , Fracture Fixation, Intramedullary/methods , Tibial Fractures/complications , Tibial Fractures/surgery , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/surgery , Brain , Lower Extremity/surgery , Treatment Outcome , Retrospective StudiesABSTRACT
Candida glabrata is a prominent opportunistic fungal pathogen of humans. The increasing incidence of C. glabrata infections is attributed to both innate and acquired resistance to antifungals. Previous studies suggest the transcription factor Pdr1 and several target genes encoding ABC transporters are critical elements of pleiotropic defense against azoles and other antifungals. This study utilizes Hermes transposon insertion profiling to investigate Pdr1-independent and Pdr1-dependent mechanisms that alter susceptibility to the frontline antifungal fluconazole. Several new genes were found to alter fluconazole susceptibility independent of Pdr1 ( CYB5 , SSK1 , SSK2 , HOG1 , TRP1 ). A bZIP transcription repressor of mitochondrial function ( CIN5 ) positively regulated Pdr1 while hundreds of genes encoding mitochondrial proteins were confirmed as negative regulators of Pdr1. The antibiotic oligomycin activated Pdr1 and antagonized fluconazole efficacy likely by interfering with mitochondrial processes in C. glabrata . Unexpectedly, disruption of many 60S ribosomal proteins also activated Pdr1, thus mimicking the effects of the mRNA translation inhibitors. Cycloheximide failed to fully activate Pdr1 in a cycloheximide-resistant Rpl28-Q38E mutant. Similarly, fluconazole failed to fully activate Pdr1 in a strain expressing a low-affinity variant of Erg11. Fluconazole activated Pdr1 with very slow kinetics that correlated with the delayed onset of cellular stress. These findings are inconsistent with the idea that Pdr1 directly senses xenobiotics and support an alternative hypothesis where Pdr1 senses cellular stresses that arise only after engagement of xenobiotics with their targets. Importance: Candida glabrata is an opportunistic pathogenic yeast that causes discomfort and death. Its incidence has been increasing because of natural defenses to our common antifungal medications. This study explores the entire genome for impacts on resistance to fluconazole. We find several new and unexpected genes can impact susceptibility to fluconazole. Several antibiotics can also alter the efficacy of fluconazole. Most importantly, we find that Pdr1 - a key determinant of fluconazole resistance - is not regulated directly through binding of fluconazole and instead is regulated indirectly by sensing the cellular stresses caused by fluconazole blockage of sterol biosynthesis. This new understanding of drug resistance mechanisms could improve the outcomes of current antifungals and accelerate the development of novel therapeutics.