Emergency Physician-Performed Point-of-Care Ultrasound of a Renal Mass.

Emergency physicians (EPs) frequently integrate point-of-care ultrasound (POCUS) into the initial bedside evaluation of patients presenting to the emergency department with acute flank pain. A POCUS-first diagnostic approach can allow EPs to promptly assess for life-threatening pathologies of the aorta and gallbladder. POCUS is also a critical bedside tool to determine renal causes of acute flank pain, such as hydronephrosis in the setting of nephrolithiasis, subcapsular hematomas, renal abscesses, pyelonephritis, and renal masses. This report illustrates a case in which EP-performed POCUS led to the incidental diagnosis of a malignant renal mass in a patient presenting with flank pain. We review the specifics of the ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) Bosniak classification system used by radiologists for risk stratification of cystic renal masses (CRMs).

Bedside Echocardiography Diagnosis of Tricuspid Valve Infective Endocarditis in the Emergency Department.

Infective endocarditis (IE) is a rare life-threatening entity that remains difficult to diagnose in the emergency department (ED). Focused cardiac ultrasound (FOCUS) with transthoracic echocardiography (TTE) is an indispensable bedside tool for the emergency physician (EP) to promptly diagnosis and expedite clinical management of IE. This report describes a case in which EP-performed FOCUS led to the early identification of right-sided tricuspid valve IE complicated with septic pulmonary emboli.

Point-of-Care Ultrasound Diagnosis of a Crohn's Disease-Related Intraabdominal Abscess in the Emergency Department.

The emergency department (ED) diagnosis of Crohn's disease (CD)-associated complications is typically established with abdominopelvic computed tomography imaging. Ultrasonography has been suggested as an effective alternative modality for diagnosing several CD complications, including intraabdominal abscesses. We report the identification of a CD-related intraabdominal abscess by emergency physician (EP)-performed point-of-care ultrasound (POCUS). This case highlights the feasibility of EPs integrating POCUS into the clinical decision-making for patients with inflammatory bowel disease in the ED.

Point-of-care ultrasound diagnosis of a pyogenic liver abscess in the emergency department.

Pyogenic liver abscess (PLA) is a rarely encountered condition in the emergency department (ED) that necessitates a timely diagnosis by the emergency physician. An early ED diagnosis is challenging as the presenting symptoms of PLA are often variable and nonspecific. The rapid bedside diagnosis of PLA with point-of-care ultrasound (POCUS) performed by emergency physicians has not been investigated thoroughly. This case report describes the expeditious identification and ED management of PLA by implementing emergency physician-performed POCUS as the initial diagnostic modality.

Bedside Ocular Ultrasound Diagnosis of a Traumatic Lens Dislocation.

Rapid identification of ophthalmologic emergencies can be challenging in the ED, and a missed or delayed diagnosis may have vision-threatening consequences. The application of ocular point-of-care ultrasound (POCUS) by the emergency physician (EP) can facilitate the timely recognition of a myriad of emergent eye conditions. This report describes a case in which EP-performed POCUS established the prompt diagnosis of a traumatic lens dislocation in a patient with chronic vision changes.

Emergency physician-performed bedside ultrasound of pyomyositis.

Point-of-care ultrasound (POCUS) is an indispensable tool for emergency physicians in the rapid bedside diagnosis of skin and soft tissue infections. The utility of POCUS for the differentiation of cellulitis and subcutaneous abscess is well established; however, there is a paucity of studies highlighting POCUS as a first-line imaging approach for pyomyositis, an uncommon skeletal muscle infection and/or intramuscular abscess formation requiring emergent diagnosis. This report describes a case in which emergency physician-performed POCUS led to the early detection and timely management of pyomyositis in the emergency department.

Emergency Physician-Performed Bedside Ultrasound of Gastric Volvulus.

Gastric volvulus (GV) is a seldomly encountered life-threatening condition that necessitates rapid diagnosis in the emergency department (ED). The diagnosis of GV is traditionally established with cross-sectional imaging and/or endoscopy with surgical confirmation. The potential role of point-of-care ultrasound (POCUS) as a bedside tool to support the early identification of GV by emergency physicians (EPs) has not been thoroughly investigated. This case report describes the expeditious diagnosis and ED management of acute GV by implementing EP-performed POCUS into critical decision making.

Right Heart Thrombus in Transit Diagnosed With Focused Cardiac Ultrasound in the Emergency Department.

The diagnosis of a right heart thrombus (RHTh) in transit associated with pulmonary embolism (PE) is an uncommon phenomenon with a high mortality rate. Timely recognition of RHTh with focused cardiac ultrasound (FOCUS) in cases of suspected PE is necessary for critical decision making in the emergency department (ED). We present a case of RHTh with submassive PE in which the patient underwent successful catheter-directed thrombolysis. This case report illustrates the significance of an emergency physician (EP) implementing FOCUS during the initial ED evaluation to rapidly diagnose RHTh in transit and initiate PE therapy without delay.

Emergent Diagnosis of a Flail Mitral Leaflet With Bedside Echocardiography.

Flail mitral leaflet (FML) with associated acute pulmonary edema and acute decompensated heart failure is an emergent condition requiring prompt recognition by the emergency physician (EP). Focused cardiac ultrasound (FOCUS) and lung ultrasound (LUS) have a vital role in the evaluation of FML in the emergency department. This case report describes the identification of a FML with EP-performed bedside echocardiography.

Point-of-Care Ultrasound Diagnosis of Pneumoperitoneum in the Emergency Department.

Prompt and accurate diagnostic evaluation of the nontraumatic acute abdomen in the emergency department (ED) is crucial to lessen mortality burden. In patients with perforated viscus and pneumoperitoneum, point-of-care ultrasound (POCUS) can assist the emergency physician (EP) in the rapid bedside diagnosis. This report describes a case in which EP-performed POCUS led to the early detection and timely management of an atypical presentation of pneumoperitoneum.

Serial Point-of-care Echocardiography Performed by an Emergency Physician to Guide Thrombolytic Management of Massive Pulmonary Embolism.

Massive pulmonary embolism (PE) is a life-threatening condition with a high mortality burden. The rapid diagnosis of PE can be supported with focused cardiac ultrasound (FOCUS) by identifying signs of right ventricular dysfunction (RVD). This case report describes a patient with hemodynamically unstable massive PE who received systemic thrombolytic therapy. Emergency physicians performed serial FOCUS examinations to assess the resolution of RVD in guidance of clinical management.

A Cost-Effective, Rapidly Constructed Simulation Model for Ultrasound-Guided Pericardiocentesis Procedural Training.

BACKGROUND: Emergent ultrasound-guided pericardiocentesis (USGP) is an uncommonly performed procedure by emergency physicians (EPs). USGP simulation models have previously been developed to increase procedural proficiency, but these models are limited for routine implementation secondary to high-cost, lengthy time to construct, and lack of durability. The objective of this study was to develop an USGP simulation model that is cost-effective, easily and rapidly constructed, and has procedure-specific fidelity. DISCUSSION: We have developed a novel tofu simulation model for USGP training. The model cost per unit was $1.81 and the average construction time was 2.5 ± 0.3 min. The model can withstand upward of 100 needle punctures. Our model provides USGP procedure-specific aspiration of a simulated pericardial effusion. CONCLUSIONS: The tofu USGP model provides a cost-effective and rapidly constructible simulation tool that could be readily integrated in EP procedural training.

Dual-Reporter Mycobacteriophages (Φ2DRMs) Reveal Preexisting Mycobacterium tuberculosis Persistent Cells in Human Sputum.

Persisters are the minor subpopulation of bacterial cells that lack alleles conferring resistance to a specific bactericidal antibiotic but can survive otherwise lethal concentrations of that antibiotic. In infections with Mycobacterium tuberculosis, such persisters underlie the need for long-term antibiotic therapy and contribute to treatment failure in tuberculosis cases. Here, we demonstrate the value of dual-reporter mycobacteriophages (Φ2DRMs) for characterizing M. tuberculosis persisters. The addition of isoniazid (INH) to exponentially growing M. tuberculosis cells consistently resulted in a 2- to 3-log decrease in CFU within 4 days, and the remaining ≤1% of cells, which survived despite being INH sensitive, were INH-tolerant persisters with a distinct transcriptional profile. We fused the promoters of several genes upregulated in persisters to the red fluorescent protein tdTomato gene in Φ2GFP10, a mycobacteriophage constitutively expressing green fluorescent protein (GFP), thus generating Φ2DRMs. A population enriched in INH persisters exhibited strong red fluorescence, by microscopy and flow cytometry, using a Φ2DRM with tdTomato controlled from the dnaK promoter. Interestingly, we demonstrated that, prior to INH exposure, a population primed for persistence existed in M. tuberculosis cells from both cultures and human sputa and that this population was highly enriched following INH exposure. We conclude that Φ2DRMs provide a new tool to identify and quantitate M. tuberculosis persister cells. IMPORTANCE: Tuberculosis (TB) is again the leading cause of death from a single infectious disease, having surpassed HIV. The recalcitrance of the TB pandemic is largely due to the ability of the pathogen Mycobacterium tuberculosis to enter a persistent state in which it is less susceptible to antibiotics and immune effectors, necessitating lengthy treatment. It has been difficult to study persister cells, as we have lacked tools to isolate these rare cells. In this article, we describe the development of dual-reporter mycobacteriophages that encode a green fluorescent marker of viability and in which the promoters of genes we have identified as induced in the persister state are fused to a gene encoding a red fluorescent protein. We show that these tools can identify heterogeneity in a cell population that correlates with propensity to survive antibiotic treatment and that the proportions of these subpopulations change in M. tuberculosis cells within human sputum during the course of treatment.

Serratia marcescens Cyclic AMP Receptor Protein Controls Transcription of EepR, a Novel Regulator of Antimicrobial Secondary Metabolites.

UNLABELLED: Serratia marcescens generates secondary metabolites and secreted enzymes, and it causes hospital infections and community-acquired ocular infections. Previous studies identified cyclic AMP (cAMP) receptor protein (CRP) as an indirect inhibitor of antimicrobial secondary metabolites. Here, we identified a putative two-component regulator that suppressed crp mutant phenotypes. Evidence supports that the putative response regulator eepR was directly transcriptionally inhibited by cAMP-CRP. EepR and the putative sensor kinase EepS were necessary for the biosynthesis of secondary metabolites, including prodigiosin- and serratamolide-dependent phenotypes, swarming motility, and hemolysis. Recombinant EepR bound to the prodigiosin and serratamolide promoters in vitro. Together, these data introduce a novel regulator of secondary metabolites that directly connects the broadly conserved metabolism regulator CRP with biosynthetic genes that may contribute to competition with other microbes. IMPORTANCE: This study identifies a new transcription factor that is directly controlled by a broadly conserved transcription factor, CRP. CRP is well studied in its role to help bacteria respond to the amount of nutrients in their environment. The new transcription factor EepR is essential for the bacterium Serratia marcescens to produce two biologically active compounds, prodigiosin and serratamolide. These two compounds are antimicrobial and may allow S. marcescens to compete for limited nutrients with other microorganisms. Results from this study tie together the CRP environmental nutrient sensor with a new regulator of antimicrobial compounds. Beyond microbial ecology, prodigiosin and serratamolide have therapeutic potential; therefore, understanding their regulation is important for both applied and basic science.

Bacterial cyclic AMP-phosphodiesterase activity coordinates biofilm formation.

Biofilm-related infections are a major contributor to human disease, and the capacity for surface attachment and biofilm formation are key attributes for the pathogenesis of microbes. Serratia marcescens type I fimbriae-dependent biofilms are coordinated by the adenylate cyclase, CyaA, and the cyclic 3',5'-adenosine monophosphate (cAMP)-cAMP receptor protein (CRP) complex. This study uses S. marcescens as a model system to test the role of cAMP-phosphodiesterase activity in controlling biofilm formation. Herein we describe the characterization of a putative S. marcescens cAMP-phosphodiesterase gene (SMA3506), designated as cpdS, and demonstrated to be a functional cAMP-phosphodiesterase both in vitro and in vivo. Deletion of cpdS resulted in defective biofilm formation and reduced type I fimbriae production, whereas multicopy expression of cpdS conferred a type I fimbriae-dependent hyper-biofilm. Together, these results support a model in which bacterial cAMP-phosphodiesterase activity modulates biofilm formation.