Diagnostic value of loop-mediated isothermal amplification in detecting lower respiratory pathogens.

INTRODUCTION: To investigate the diagnostic value of loop-mediated thermostatic amplification (LAMP) in detecting pathogenic bacteria from bronchoalveolar lavage fluid (BALF) of patients with pulmonary disorders combined with lower respiratory tract infections (LRTI). METHODOLOGY: This cross-sectional study included patients with pulmonary disorders combined with LRTI, including chronic obstructive pulmonary disease (COPD), bronchiectasis, or lung cancer, hospitalized in Meizhou People's Hospital between January 2020 and October 2021. BALF was collected using local bronchoalveolar lavage and electronic bronchoscopy. The presence of the pathogens was confirmed using the LAMP method and the bacterial culture method. RESULTS: In total, 249 patients were included (135 with COPD, 73 with bronchiectasis, and 41 with lung cancer). The proportions of Methicillin-resistant Staphylococcus aureus (4.8% vs 0.4%, p = 0.02) and Haemophilus influenzae (6.8% vs 0.4%, p < 0.001) detected by the LAMP method was higher, while the proportion of Pseudomonas aeruginosa was lower compared with that of the culture method (6.8% vs 12.4%, p = 0.034). The bacterial species with the highest agreement coefficient was Stenotrophomonas maltophilia (Kappa = 0.798, p < 0.001). Furthermore, 9 COPD patients exhibited mixed infections as determined by the LAMP method, whereas the culture method detected only 2 of these cases (1.48%) (p < 0.05). CONCLUSIONS: LAMP can detect more pathogenic bacteria, notably Haemophilus influenza, Methicillin-resistant Staphylococcus aureus, and atypical pathogens in patients with clinically common pulmonary disorders combined with LRTI. LAMP may provide etiological evidence to guide the clinical use of antibiotics in primary hospitals.

Predictive roles of D-dimer for mortality of patients with community-acquired pneumonia: a systematic review and meta-analysis.

OBJECTIVE: To explore the predictive roles of D-dimer for the mortality of patients with community-acquired pneumonia (CAP). METHODS: This was a systematic review and meta-analysis. We searched the following databases: PubMed, EMBASE, Web of Science, Ovid MEDLINE, and Cochrane Library from their inception to July 26, 2020. Studies exploring the relationship between blood D-dimer levels and CAP-related mortality were selected. In this meta-analysis, we calculated mortality rates, sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios. RESULTS: The search identified 1,073 articles, 8 of which (a total of 2,126 patients) were included in this meta-analysis. The pooled mortality rate of the overall sample was 0.10 (95% CI, 0.08-0.14). The levels of blood D-dimer in the nonsurvivors were significantly higher than those in the survivors (weighted mean difference = 1.03 mg/L [95% CI, 0.81-1.26]; p < 0.00001). The area under the summary ROC curve for the optimal cutoff value of D-dimer as a predictor of mortality was 0.848 (SE = 0.046), and the pooled negative likelihood ratio for D-dimer within the normal range was 0.24 (95% CI, 0.11-0.53). CONCLUSIONS: Blood D-dimer might be helpful for the initial assessment of mortality risk of patients with CAP. D-dimer levels within the normal range indicate low risk of mortality. Because of the small sample size in our study, our findings should be further explored and validated in future studies with larger sample sizes.

Correlation of Luminal Mucus Score in Large Airways with Lung Function and Quality of Life in Severe Acute Exacerbation of COPD: A Cross-Sectional Study.

BACKGROUND AND OBJECTIVE: Luminal mucus plugging in small airways is associated with lung function decline and death of patients with chronic obstructive pulmonary disease (COPD). However, little attention has been paid to the possible role of mucus in large airways in acute exacerbation of COPD (AECOPD). Therefore, this study aimed to explore the relationship between the luminal mucus score of large airways and other physiological parameters of severe AECOPD. SUBJECTS AND METHODS: A total of 74 AECOPD inpatients were enrolled in this cross-sectional study. All patients underwent lung function tests and bronchoscopy, and their luminal mucus was observed and scored through bronchoscopy. Four questionnaires, including the St. George Respiratory Questionnaire (SGRQ), modified Medical Research Council dyspnea scale (mMRC), COPD Assessment Test (CAT) and Exacerbation of Chronic pulmonary disease Tool (EXACT), were used to assess health-related quality of life (HRQoL). RESULTS: The luminal mucus score of large airways was significantly correlated with spirometry parameters and HRQoL score. Both mMRC grade and SGRQ score were significantly positively correlated with luminal mucus score (ρ=0.527, P<0.001; ρ=0.441, P<0.001, respectively). Forced expiratory flow at 25% to 75% of the FVC (FEF25%-75%) and FEV1% predicted, as functional measures reflecting small airway disease, were significantly negatively correlated with luminal mucus score (ρ=-0.518, P<0.001; ρ=-0.498, P<0.001, respectively). The stepwise multiple linear regression model suggested that mMRC grade and FEV1% predicted could predict luminal mucus score (R 2=0.348, F=18.960, P<0.001). CONCLUSION: For severe acute exacerbation of COPD, bronchoscopy-identified luminal mucus in large airways is associated with reduced lung function and worse health-related quality of life.