Enhanced Biofilm Formation by Tetracycline in a Staphylococcus aureus Naturally Lacking ica Operon and atl.

Staphylococcus aureus is a major, widespread pathogen, and its biofilm-forming characteristics make it even more difficult to eliminate by biocides. Tetracycline (TCY) is a major broad-spectrum antibiotic, the residues of which can cause deleterious health impacts, and subinhibitory concentrations of TCY have the potential to increase biofilm formation in S. aureus. In this study, we showed how the biofilm formation of S. aureus 123786 is enhanced in the presence of TCY at specific subinhibitory concentrations. S. aureus 123786 used in this study was identified as Staphylococcal Cassette Chromosome mec III, sequence type239 and naturally lacking ica operon and atl gene. Two assays were performed to quantify the formation of S. aureus biofilm. In the crystal violet (CV) assay, the absorbance values of biofilm stained with CV at optical density (OD)540 nm increased after 8 and 16 hr of incubation when the concentration of TCY was 1/2 minimum inhibitory concentration (MIC), whereas at the concentration of 1/16 MIC, the absorbance values increased after 16 and 24 hr of incubation. In tetrazolium salt reduction assay, the absorbance value at OD490 nm of S. aureus 123786 biofilms mixed with 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium solution increased after 8 hr when the concentration of TCY was 1/4 MIC, which may be correlated with the higher proliferation and maturation of biofilm. In conclusion, the biofilm formation of S. aureus 123786 could be enhanced in the presence of TCY at specific subinhibitory concentrations.

Positional dyspnea due to excessive dynamic airway collapse: A case report.

RATIONALE: Excessive dynamic airway collapse (EDAC) is a form of dynamic central airway obstruction, with characteristic of excessive dynamic invagination of airway posterior wall membrane and structurally intact airway cartilage. We report a rare case of EDAC with a marked positional component. PATIENT CONCERNS: A 73-year-old man was admitted to our hospital owing to dyspnea in right recumbent position (RRP). Also only in RRP, strong rhonchi was auscultated bilaterally through entire respiratory phase. He had gone through 3 episodes of resections on left lung due to hemoptysis caused by bronchiectasis, so he had only segment B1 + 2 and B3 left. DIAGNOSES: The spirometry results indicated that he had chronic obstructive pulmonary disease (COPD). The bronchoscopy revealed that in RRP, there was severe inward bulging of the posterior membrane of right main bronchus (RMB), which was worsened at expiratory phase. The EDAC of RMB was suspected, and was confirmed by an expiratory phase computed tomography (CT) in RRP. The EDAC was likely due to COPD, and the positional component was most likely to be caused by the removal of majority of his left lung. INTERVENTIONS: Considering locality of EDAC and his overall stability, he was given a conservative approach. He was prescribed with budesonide/glycopyrrolate/formoterol for COPD and followed up. OUTCOMES: Two months later, the patient had relived dyspnea and weaker wheezing in RRP, and he had a good social and physical recovery. LESSONS: Dyspnea may present as a diagnostic challenge, and it is rarely accompanied with a positional component. EDAC is an uncommon cause of dyspnea. This case illustrates the possible role of bronchoscopy and dynamic CT in dynamic evaluation of airway.

Corrigendum: First report on the rapid detection and identification of methicillin-resistant Staphylococcus aureus (MRSA) in viable but non-culturable (VBNC) under food storage conditions.

[This corrects the article DOI: 10.3389/fmicb.2020.615875.].

The CURB65 score predicted 180-day mortality of non-small cell lung carcinoma patients with immune checkpoint inhibitor-associated pneumonitis: A pilot retrospective analysis.

Introduction: The immune checkpoint inhibitor-associated pneumonitis (CIP) is a particularly worrisome and potentially lethal form of immune-related adverse events. An objective and evidence-based assessment tool for evaluating the severity of CIP is in urgent need. CURB65 (consciousness, urea nitrogen, respiratory rate, blood pressure, and age) is a potential candidate to meet the need. Methods: A retrospective study was conducted to explore preliminarily if CURB65 could predict the mortality in non-small cell lung carcinoma (NSCLC) patients with CIP. Results: A total number of 28 NSCLC patients with CIP were included in the current study and classified into low-CURB65 group (n = 21) and high-CURB65 group (n = 7). Mortality after onset of CIP was consistently higher in the high-CURB65 group than in the low-CURB65 group (30-day: 57.1% vs. 0; 90-day: 71.4% vs. 4.76%; 180-day:71.4% vs. 14.29%). Two patients (9.5%) in the low-CURB65 group had severe CIP, and more than half of patients in the high-CURB65 group had severe CIP (p = 0.0008). The patients in the high-CURB65 group received more aggressive treatment. Both groups showed a predominant organizing pneumonia-like pattern on CT scan. CURB65 was moderately correlated with the American Society of Clinical Oncology (ASCO) grade of CIP, with a Pearson correlation coefficient R of 0.524. Conclusion: CURB65 accurately stratified the risk of mortality in NSCLC patients with CIP. CURB65 might complement the ASCO grade in the assessment and prediction of mortality in these populations.

Daily versus three-times-weekly azithromycin in Chinese patients with non-cystic fibrosis bronchiectasis: protocol for a prospective, open-label and randomised controlled trial.

INTRODUCTION: Non-cystic fibrosis bronchiectasis (NCFB) brought a heavy healthcare burden worldwide. Macrolide maintenance therapy was proved to be helpful in reducing exacerbation of NCFB. However, the optimal dosing regimens of macrolides have not been determined, and its efficacy in Chinese NCFB population has not been validated. This protocol describes a head-to-head clinical trial designed to compare the efficacy of two dosing regimens of azithromycin in Chinese NCFB population. METHODS AND ANALYSIS: This prospective, open-label and randomised controlled trial will be conducted in the First People's Hospital of Jiashan, China. Eligible patients with high-resolution CT defined NCFB will be randomly divided into three groups, which will receive either 250 mg daily azithromycin, or 500 mg three-times-weekly azithromycin or no treatment for 6 months. They will be followed up for another 6 months without treatment. The primary outcome is the mean rate of protocol-defined pulmonary exacerbation at 6 months. ETHICS AND DISSEMINATION: Ethical approval was obtained from the First People's Hospital of Jiashan Ethics Committee. The findings will be disseminated in peer-reviewed publications. TRIAL REGISTRATION NUMBER: ChiCTR2100052906.

Dynamic monitor of CT scan within short interval in invasive pulmonary aspergillosis for nonneutropenic patients: a retrospective analysis in two centers.

BACKGROUND: In nonneutropenic patients with underlying respiratory diseases (URD), invasive pulmonary aspergillosis (IPA) is a life-threatening disease. Yet establishing early diagnosis in those patients remains quite a challenge. METHODS: A retrospective series of nonneutropenic patients with probable or proven IPA were reviewed from January 2014 to May 2018 in Department of Respiratory Medicine of two Chinese hospitals. Those patients were suspected of IPA and underwent lung computed tomography (CT) scans twice within 5-21 days. The items required for IPA diagnosis were assessed by their host factors, mycological findings and CT scans according to the European Organization for Research and Treatment of Cancer (EORTC) and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (MSG) criteria (EORTC/MSG criteria). RESULTS: Together with the risk factors, mycological findings and nonspecific radiological signs on first CT, ten patients were suspected of IPA. With the appearance of cavities on second CT scan in the following days, all patients met the criteria of probable or possible IPA. Except one patient who refused antifungal treatment, nine patients received timely antifungal treatment and recovered well. One of the nine treated IPA cases was further confirmed by pathology, one was confirmed by biopsy. CONCLUSIONS: Dynamic monitor of CT scan provided specific image evidences for IPA diagnosis. This novel finding might provide a noninvasive and efficient strategy in IPA diagnosis with URD.

Eosinopenia Predicting Long-term Mortality in Hospitalized Acute Exacerbation of COPD Patients with Community-acquired Pneumonia-A Retrospective Analysis.

BACKGROUND: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) could be triggered by community-acquired pneumonia (CAP). Peripheral blood eosinopenia are strongly associated with increased mortality. In hospitalized AECOPD patients with CAP, eosinopenia may be used to identify patients with high risk of death on admission. METHODS: We conducted a retrospective cohort study in 82 hospitalized AECOPD patients with CAP. Patients who had received systemic corticosteroids preadmission were excluded. The patients were identified by individual case file review. According to blood eosinophil count, patients were grouped as eosinopenia (<50/µL) and non-eosinopenia (≥50/µL). Association of eosinopenia with infection and 18-month survival were analyzed using appropriate statistical methods. RESULTS: Baseline demographic, comorbidity, CURB65 and Pneumonia Severity Index scores were similar between two groups. The eosinopenia group had significantly higher pro-brain natriuretic peptide, D-dimer, neutrophil percentage, and lower lymphocyte count and lymphocyte percentage. The eosinopenia group had significantly higher C-reactive protein (median 77.30 vs 16.55, p=0.008) and procalcitonin (median 0.32 vs 0.12, p=0.001). Survival at 18 months after hospital discharge was significantly lower in the eosinopenia group vs non-eosinopenia group (log rank, p=0.002). CONCLUSION: Eosinopenia (<50/µL) was a strong predictor of 18-month mortality and associated with more severe infection in hospitalized AECOPD patients with CAP. Eosinophil count at admission can be used as a prognosis marker of mortality in those population.

First Report on the Rapid Detection and Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) in Viable but Non-culturable (VBNC) Under Food Storage Conditions.

Formation of viable but non-culturable (VBNC) status in methicillin-resistant Staphylococcus aureus (MRSA) has never been reported, and it poses a significant concern for food safety. Thus, this study aimed to firstly develop a rapid, cost-effective, and efficient testing method to detect and differentiate MRSA strains in the VBNC state and further apply this in real food samples. Two targets were selected for detection of MRSA and toxin, and rapid isothermal amplification detection assays were developed based on cross-priming amplification methodology. VBNC formation was performed for MRSA strain in both pure culture and in artificially contaminated samples, then propidium monoazide (PMA) treatment was further conducted. Development, optimization, and evaluation of PMA-crossing priming amplification (CPA) were further performed on detection of MRSA in the VBNC state. Finally, application of PMA-CPA was further applied for detection on MRSA in the VBNC state in contaminated food samples. As concluded in this study, formation of the VBNC state in MRSA strains has been verified, then two PMA-CPA assays have been developed and applied to detect MRSA in the VBNC state from pure culture and food samples.

House dust mite induces Sonic hedgehog signaling that mediates epithelial­mesenchymal transition in human bronchial epithelial cells.

Epithelial­mesenchymal transition (EMT) provides a valuable source of fibroblasts that produce extracellular matrix in airway walls. The Sonic hedgehog (SHH) signaling pathway plays an essential role in regulating tissue turnover and homeostasis. SHH is strikingly upregulated in the bronchial epithelia during asthma. Snail1 is a major target of SHH signaling, which regulates EMT and fibroblast motility. The present study was designed to ascertain whether the combination of house dust mite (HDM) and transforming growth factor ß1 (TGF­ß1) could induce EMT via the SHH signaling pathway in human bronchial epithelial cells (HBECs). HBEC cultures were treated with HDM/TGF­ß1 for different periods of time. The involvement of SHH signaling and EMT biomarkers was evaluated by quantitative real­time PCR, western blotting and immunofluorescence staining. Small­interfering RNA (siRNA) for glioma­associated antigen­1 (Gli1) or cyclopamine was used to inhibit SHH signaling in HBECs. HBECs stimulated by HDM/TGF­ß1 exhibited morphological features of EMT. E­cadherin (an epithelial marker) was decreased after a 72­h exposure to HDM/TGF­ß1 compared to that in the control cells, and the expression of type I collagen and FSP1 (mesenchymal markers) was increased. HDM/TGF­ß1 activated the SHH signaling pathway in HBECs, which led to Gli1 nuclear translocation and the transcriptional activation of Snail1 expression. Moreover, gene silencing or the pharmacological inhibition of Gli1 ameliorated EMT. In summary, these findings suggest that HDM/TGF­ß1 may induce EMT in HBECs via an SHH signaling mechanism. Inhibition of SHH signaling may be a novel therapeutic method for preventing airway remodeling in asthma.

Long non-coding RNA OECC promotes cell proliferation and metastasis through the PI3K/Akt/mTOR signaling pathway in human lung cancer.

Lung cancer is one of the most common malignancies worldwide; however, its detailed molecular mechanism remains largely unknown. Long non-coding RNAs (lncRNAs) have been identified to serve critical roles in tumorigenesis. The aim of the present study was to investigate the role of a newly identified lncRNA, overexpressed in colorectal cancer (OECC), in human lung cancer. It was initially revealed that the relative transcript level of OECC was highly upregulated in clinical human lung cancer tissues as well as in cultured lung cancer cells. Knockdown of OECC with specific short hairpin RNAs in lung cancer cell lines A549 and 95D inhibited colony formation and cell viability, as evidenced using colony formation assays and cell proliferation assays. Furthermore, depletion of OECC in A549 and 95D cells suppressed migration and invasion, which was verified using Transwell assays. RNA-sequence analysis suggested that the phosphoinositide 3-kinase/protein kinase B (Akt)/mammalian target of rapamycin signaling pathway was positively regulated by OECC in lung cancer cells A549. In addition, overexpression of Akt in OECC-depleted A549 and 95D cells reversed the suppression of proliferation and migration caused by OECC depletion. The results of the present study identified lncRNA OECC as a novel regulator of lung cancer progression and provided new clues for the clinical treatment of lung cancer.

Adipose Tissue-Derived Mesenchymal Stem Cells Attenuate Pulmonary Infection Caused by Pseudomonas aeruginosa via Inhibiting Overproduction of Prostaglandin E2.

RATIONALE: New strategies for treating Pseudomonas aeruginosa pulmonary infection are urgently needed. Adipose tissue-derived mesenchymal stem cells (ASCs) may have a potential therapeutic role in P. aeruginosa-induced pulmonary infection. METHODS: The therapeutic and mechanistic effects of ASCs on P. aeruginosa pulmonary infection were evaluated in a murine model of P. aeruginosa pneumonia. RESULTS: ASCs exhibited protective effects against P. aeruginosa pulmonary infection, evidenced by reduced bacterial burdens, inhibition of alveolar neutrophil accumulation, decreased levels of myeloperoxidase, macrophage inflammatory protein-2 and total proteins in broncho-alveolar lavage fluid (BALF), and attenuated severity of lung injury. ASCs had no effects on BALF and serum levels of keratinocyte growth factor or Ang-1. ASCs had no effects on the levels of insulin growth factor 1 (IGF-1) in BALF, but increased IGF-1 levels in serum. ASCs inhibited the overproduction of prostaglandin E2 (PGE2 ) by decreasing the expression of cyclooxygenase-2 (COX2) and enhancing the expression of 15-PGDH. In addition, the addition of exogenous PGE2 with ASCs abolished many of the protective effects of ASCs, and administrating PGE2 alone exacerbated lung infection. By inhibiting production of PGE2 , ASCs improved phagocytosis and the bactericidal properties of macrophages. Furthermore suppressing PGE2 signaling by COX2 inhibition or EP2 inhibition exhibited protective effects against pulmonary infection as well. CONCLUSIONS: In a murine model of P. aeruginosa pneumonia, ASCs exhibited protective effects by inhibiting production of PGE2 , which subsequently improved phagocytosis and the bactericidal properties of macrophages. ASCs may provide a new strategy for managing pulmonary infection caused by P. aeruginosa.

Persistent suppression of ocular neovascularization with intravitreal administration of AAVrh.10 coding for bevacizumab.

Vascular endothelial growth factor (VEGF) plays an important role in the pathogenesis of neovascular age-related macular degeneration and diabetic retinopathy. Bevacizumab, an anti-VEGF monoclonal antibody, is efficacious for these disorders, but requires monthly intravitreal administration, with associated discomfort, cost, and adverse event risk. We hypothesized that a single intravitreal administration of adeno-associated virus (AAV) vector expressing bevacizumab would result in persistent eye expression of bevacizumab and suppress VEGF-induced retinal neovascularization. We constructed an AAV rhesus serotype rh.10 vector to deliver bevacizumab (AAVrh.10BevMab) and assessed its ability to suppress neovascularization in transgenic mice overexpressing human VEGF165 in photoreceptors. Intravitreal AAVrh.10BevMab directed long-term bevacizumab expression in the retinal pigmented epithelium. Treated homozygous mice had reduced levels of neovascularization, with 90±4% reduction 168 days following treatment. Thus, a single administration of AAVrh.10BevMab provides long-term suppression of neovascularization without the costs and risks associated with the multiple administrations required for the current conventional bevacizumab monoclonal drug delivery.