The biofilm proteome of Staphylococcus aureus and its implications for therapeutic interventions to biofilm-associated infections.

Staphylococcus aureus is a major healthcare concern due to its ability to inflict life-threatening infections and evolve antibiotic resistance at an alarming pace. It is frequently associated with hospital-acquired infections, especially device-associated infections. Systemic infections due to S. aureus are difficult to treat and are associated with significant mortality and morbidity. The situation is worsened by the ability of S. aureus to form social associations called biofilms. Biofilms embed a community of cells with the ability to communicate with each other and share resources within a polysaccharide or protein matrix. S. aureus establish biofilms on tissues and conditioned abiotic surfaces. Biofilms are hyper-tolerant to antibiotics and help evade host immune responses. Biofilms exacerbate the severity and recalcitrance of device-associated infections. The development of a biofilm involves various biomolecules, such as polysaccharides, proteins and nucleic acids, contributing to different structural and functional roles. Interconnected signaling pathways and regulatory molecules modulate the expression of these molecules. A comprehensive understanding of the molecular biology of biofilm development would help to devise effective anti-biofilm therapeutics. Although bactericidal agents, antimicrobial peptides, bacteriophages and nano-conjugated anti-biofilm agents have been employed with varying levels of success, there is still a requirement for effective and clinically viable anti-biofilm therapeutics. Proteins that are expressed and utilized during biofilm formation, constituting the biofilm proteome, are a particularly attractive target for anti-biofilm strategies. The proteome can be explored to identify potential anti-biofilm drug targets and utilized for rational drug discovery. With the aim of uncovering the biofilm proteome, this chapter explores the mechanism of biofilm formation and its regulation. Furthermore, it explores the antibiofilm therapeutics targeted against the biofilm proteome.

Protective role of CFTR during fungal infection of cystic fibrosis bronchial epithelial cells with Aspergillus fumigatus.

Lung infection with the fungus Aspergillus fumigatus (Af) is a common complication in cystic fibrosis (CF) and is associated with loss of pulmonary function. We established a fungal epithelial co-culture model to examine the impact of Af infection on CF bronchial epithelial barrier function using Af strains 10AF and AF293-GFP, and the CFBE41o- cell line homozygous for the F508del mutation with (CF+CFTR) and without (CF) normal CFTR expression. Following exposure of the epithelial surface to Af conidia, formation of germlings (early stages of fungal growth) was detected after 9-12 hours and hyphae (mature fungal growth) after 12-24 hours. During fungal morphogenesis, bronchial epithelial cells showed signs of damage including rounding, and partial detachment after 24 hours. Fluorescently labeled conidia were internalized after 6 hours and more internalized conidia were observed in CF compared to CF+CFTR cells. Infection of the apical surface with 10AF conidia, germlings, or hyphae was performed to determine growth stage-specific effects on tight junction protein zona occludens protein 1 (ZO-1) expression and transepithelial electrical resistance (TER). In response to infection with conidia or germlings, epithelial barrier function degraded time-dependently (based on ZO-1 immunofluorescence and TER) with a delayed onset in CF+CFTR cell monolayers and required viable fungi and apical application. Infection with hyphae caused an earlier onset and faster rate of decline in TER compared to conidia and germlings. Gliotoxin, a major Af virulence factor, caused a rapid decline in TER and induced a transient chloride secretory response in CF+CFTR but not CF cells. Our findings suggest growth and internalization of Af result in deleterious effects on bronchial epithelial barrier function that occurred more rapidly in the absence of CFTR. Bronchial epithelial barrier breakdown was time-dependent and morphotype-specific and mimicked by acute administration of gliotoxin. Our study also suggests a protective role for CFTR by turning on CFTR-dependent chloride transport in response to gliotoxin, a mechanism that will support mucociliary clearance, and could delay the loss of epithelial integrity during fungal development in vivo.

Anxiety and Depression Diagnoses and the Cough Severity Index: A Retrospective Study.

Background: As mental health comorbidities can impact patient perception of symptoms, understanding a potential association of anxiety and depression with patients' perception of their cough may provide insight into preferred treatment plans. Methods: A retrospective cohort study of patients presenting with chronic cough was completed. Demographics, anxiety and depression diagnoses, and patient-reported outcome measures were collected. Patient-reported outcomes between the four groups of patients-anxiety only, depression only, anxiety and depression, and none of these conditions-were compared using Kruskal-Wallis and Mann-Whitney U tests that were used for post-hoc analysis. Results: Cough Severity Index scores were higher in those with both anxiety and depression as compared to neither, with a median score of 26 (range: 5-39) versus 19 (range: 1-38), respectively (P = .041). These results were persistent also after controlling for sex and smoking status in the robust regression analysis. Conclusions: Patients with prior diagnoses of anxiety and depression self-reported more severe symptoms for chronic cough. Adequately understanding the association of mental health with perceived cough severity may help for more individualized, successful treatment plans.

Secretory proteins in the orchestration of microbial virulence: The curious case of Staphylococcus aureus.

Microbial virulence showcases an excellent model for adaptive changes that enable an organism to survive and proliferate in a hostile environment and exploit host resources to its own benefit. In Staphylococcus aureus, an opportunistic pathogen of the human host, known for the diversity of the disease conditions it inflicts and the rapid evolution of antibiotic resistance, virulence is a consequence of having a highly plastic genome that is amenable to quick reprogramming and the ability to express a diverse arsenal of virulence factors. Virulence factors that are secreted to the host milieu effectively manipulate the host conditions to favor bacterial survival and growth. They assist in colonization, nutrient acquisition, immune evasion, and systemic spread. The structural and functional characteristics of the secreted virulence proteins have been shaped to assist S. aureus in thriving and disseminating effectively within the host environment and exploiting the host resources to its best benefit. With the aim of highlighting the importance of secreted virulence proteins in bacterial virulence, the present chapter provides a comprehensive account of the role of the major secreted proteins of S. aureus in orchestrating its virulence in the human host.

Digital ischemia in Behçet's disease: case-based review.

Behçet's disease is a rare chronic autoimmune disease affecting primarily Middle and East Asian populations between the ages of 20 and 40 years. Behçet's disease manifests with oral and genital mucocutaneous lesions, ocular disease, venous thrombosis, and central nervous system degradation. Treatment can be challenging and may require immunosuppressive agents and/or topical wound-care. While larger vascular involvement has been reported, digital ischemia due to small-vessel involvement has not been well described in the literature. Based on a systematic literature review, we were only able to find seven published cases of limb ischemia, none of which reported digital involvement. We present a unique case of Behçet's disease with severe digital ischemia and ulceration caused by small-vessel involvement. The patient was managed successfully with antiplatelet, immunosuppressants, and anti-inflammatories with complete resolution of the ischemic symptoms. By focusing on small-vessel involvement and digital ischemia, we provide insight into clinical presentation and treatment for this very rare vascular manifestation of Behçet's disease.

Segmental arterial mediolysis (SAM): Systematic review and analysis of 143 cases.

Segmental arterial mediolysis (SAM) is a rare but serious nonatherosclerotic, noninflammatory vasculopathy of unknown etiology that often results in dissection, aneurysm, occlusion, or stenosis of, primarily, the abdominal arteries. Current literature lacks consensus on diagnostic criteria and management options for SAM. This review summarizes 143 cases and aims to advance appropriate recognition and management of SAM. Literature review of all relevant SAM case studies from 2005 to 2018 yielded 126 individual SAM cases from 66 reports. We identified 17 additional SAM cases from our center, bringing our analysis to 143 patients. Patients with SAM were most commonly men (68%) in their 60s. Hypertension (43%), tobacco use (12%), and hyperlipidemia (12%) were common comorbidities. Abdominal pain (80%) and intraabdominal bleeding (50%) were the most common presenting symptoms. Computed tomography was the most frequently used imaging method (78%), and histology was available in 44% of cases. The most commonly affected vessels were the superior mesenteric (53%), hepatic (45%), celiac (36%), renal (26%), and splenic (25%) arteries with aneurysm (76%), dissection (61%), and arterial rupture (46%). Treatments included coil embolization (28%), abdominal organ surgery (24%), open arterial repair (21%), and medical management (20%). Case-specific treatment modalities yielded symptom relief in the vast majority (91%) of patients, with a mortality rate of 7%.

Aortitis caused by antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis: a case-based review.

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is a systemic necrotizing small vessel vasculitis primarily affecting elderly patients. Neutrophil apoptosis and release of pro-inflammatory mediators promote small vessel inflammation and hence multi-organ disease. It rarely affects larger vessels with extremely rare aortic involvement. Diagnosis is made based on clinical presentation, tissue biopsy of affected organ, as well as immunofluorescence and ELISA assays for ANCA. Management includes immunosuppression (e.g., glucocorticoids, cyclophosphamide and rituximab) and supportive therapy. We present a rare case of a younger patient with AAV involving the aorta. The patient's diagnosis was supported by clinical presentation, systemic organ involvement, strongly positive c-ANCA, and skin as well as aortic tissue biopsy results. After failing multiple immunosuppressants, he responded well to rituximab with improved symptoms, inflammatory markers, and imaging findings. Based on our literature review, we were only able to find ten cases of ANCA-related vasculitis involving the aorta. This is the first reported case of successful treatment of AAV-related aortitis using rituximab. Our case report and literature review provide insight into treatment of severe cases of AAV with aortic involvement.

Impaired PGE2-stimulated Cl- and HCO3- secretion contributes to cystic fibrosis airway disease.

BACKGROUND: Airway mucociliary clearance (MCC) is an important defense mechanism against pulmonary infections and is compromised in cystic fibrosis (CF). Cl- and HCO3- epithelial transport are integral to MCC. During pulmonary infections prostaglandin E2 (PGE2) production is abundant. AIM: To determine the effect of PGE2 on airway Cl- and HCO3- secretion and MCC in normal and CF airways. METHODS: We examined PGE2 stimulated MCC, Cl- and HCO3- secretion using ferret trachea, human bronchial epithelial cell cultures (CFBE41o- with wildtype CFTR (CFBE41 WT) or homozygous F508del CFTR (CFBE41 CF) and human normal bronchial submucosal gland cell line (Calu-3) in Ussing chambers with or without pH-stat. RESULTS: PGE2 stimulated MCC in a dose-dependent manner and was partially impaired by CFTRinh-172. PGE2-stimulated Cl- current in ferret trachea was partially inhibited by CFTRinh-172, with niflumic acid eliminating the residual current. CFBE41 WT cell monolayers produced a robust Cl- and HCO3- secretory response to PGE2, both of which were completely inhibited by CFTRinh-172. CFBE41 CF cells exhibited no response to PGE2. In Calu-3 cells, PGE2 stimulated Cl- and HCO3- secretion. Cl- secretion was partially inhibited by CFTRinh-172, with additional inhibition by niflumic acid. HCO3- secretion was completely inhibited by CFTRinh-172. CONCLUSIONS: PGE2 stimulates bronchotracheal MCC and this response is decreased in CF. In CF airway, PGE2-stimulated Cl- and HCO3- conductance is impaired and may contribute to decreased MCC. There remains a CFTR-independent Cl- current in submucosal glands, which if exploited, could represent a means of improving airway Cl- secretion and MCC in CF.