Causative agent distribution and antibiotic therapy assessment among adult patients with community acquired pneumonia in Chinese urban population

<p>Abstract</p> <p>Background</p> <p>Knowledge of predominant microbial patterns in community-acquired pneumonia (CAP) constitutes the basis for initial decisions about empirical antimicrobial treatment, so a prospective study was performed during 2003–2004 among CAP of adult Chinese urban populations.</p> <p>Methods</p> <p>Qualified patients were enrolled and screened for bacterial, atypical, and viral pathogens by sputum and/or blood culturing, and by antibody seroconversion test. Antibiotic treatment and patient outcome were also assessed.</p> <p>Results</p> <p>Non-viral pathogens were found in 324/610 (53.1%) patients among whom <it>M. pneumoniae </it>was the most prevalent (126/610, 20.7%). Atypical pathogens were identified in 62/195 (31.8%) patients carrying bacterial pathogens. Respiratory viruses were identified in 35 (19%) of 184 randomly selected patients with adenovirus being the most common (16/184, 8.7%). The nonsusceptibility of <it>S. pneumoniae </it>to penicillin and azithromycin was 22.2% (Resistance (R): 3.2%, Intermediate (I): 19.0%) and 79.4% (R: 79.4%, I: 0%), respectively. Of patients (312) from whom causative pathogens were identified and antibiotic treatments were recorded, clinical cure rate with β-lactam antibiotics alone and with combination of a β-lactam plus a macrolide or with fluoroquinolones was 63.7% (79/124) and 67%(126/188), respectively. For patients having mixed <it>M. pneumoniae </it>and/or <it>C. pneumoniae </it>infections, a better cure rate was observed with regimens that are active against atypical pathogens (e.g. a β-lactam plus a macrolide, or a fluoroquinolone) than with β-lactam alone (75.8% vs. 42.9%, <it>p </it>= 0.045).</p> <p>Conclusion</p> <p>In Chinese adult CAP patients, <it>M. pneumoniae </it>was the most prevalent with mixed infections containing atypical pathogens being frequently observed. With <it>S. pneumoniae</it>, the prevalence of macrolide resistance was high and penicillin resistance low compared with data reported in other regions.</p

Diagnostic Potential of microRNAs in Extracellular Vesicles Derived from Bronchoalveolar Lavage Fluid for Pneumonia&mdash;A Preliminary Report

Current clinical needs require the development and use of rapid and effective diagnostic indicators to accelerate the identification of pneumonia and the process of microbiological diagnosis. MicroRNAs (miRNAs) in extracellular vesicles (EVs) have become attractive candidates for novel biomarkers to evaluate the presence and progress of many diseases. We assessed their performance as biomarkers of pneumonia. Patients were divided into the pneumonia group (with pneumonia) and the control group (without pneumonia). We identified and compared two upregulated miRNAs in EVs derived from bronchoalveolar lavage fluid (BALF-EVs) between the two groups (PmiR&ndash;17&ndash;5p = 0.009; PmiR&ndash;193a&ndash;5p = 0.031). Interestingly, in cell-debris pellets and EVs-free supernatants derived from bronchoalveolar lavage fluid (BALF-cell-debris pellets and BALF-EVs-free supernatants), total plasma, and EVs derived from plasma (plasma-EVs), the expression of miR&ndash;17&ndash;5p and miR&ndash;193a&ndash;5p showed no difference between pneumonia group and control group. In vitro experiments revealed that miR&ndash;17&ndash;5p and miR&ndash;193a&ndash;5p were strikingly upregulated in EVs derived from macrophages stimulated by lipopolysaccharide. MiR&ndash;17&ndash;5p (area under the curve, AUC: 0.753) and miR&ndash;193a&ndash;5p (AUC: 0.692) in BALF-EVs are not inferior to procalcitonin (AUC: 0.685) in the diagnosis of pneumonia. Furthermore, miR&ndash;17&ndash;5p and miR&ndash;193a&ndash;5p in BALF-EVs had a significantly higher specificity compared to procalcitonin and could be served as a potential diagnostic marker. MiR&ndash;17&ndash;5p and miR&ndash;193a&ndash;5p in EVs may be involved in lung inflammation by influencing the forkhead box O (FoxO) signaling pathway and protein processing in endoplasmic reticulum. This study is one of the few studies which focused on the potential diagnostic role of miRNAs in BALF-EVs for pneumonia and the possibility to use them as new biomarkers for a rapid and early diagnosis

Relatively Low Level of Antigen-specific Monocytes Detected in Blood from Untreated Tuberculosis Patients Using CD4⁺ T-cell Receptor Tetramers

<div><p>The <em>in vivo</em> kinetics of antigen-presenting cells (APCs) in patients with advanced and convalescent tuberculosis (TB) is not well characterized. In order to target <em>Mycobacterium tuberculosis</em> (MTB) peptides- and HLA-DR-holding monocytes and macrophages, 2 MTB peptide-specific CD4⁺ T-cell receptor (TCR) tetramers eu and hu were successfully constructed. Peripheral blood (PBL) samples from inpatients with advanced pulmonary TB (PTB) were analyzed using flow cytometry, and the percentages of tetramer-bound CD14⁺ monocytes ranged from 0.26–1.44% and 0.21–0.95%, respectively; significantly higher than those measured in PBL samples obtained from non-TB patients, healthy donors, and umbilical cords. These tetramers were also able to specifically detect macrophages <em>in situ via</em> immunofluorescent staining. The results of the continuous time-point tracking of the tetramer-positive rates in PBL samples from active PTB outpatients undergoing treatment show that the median percentages were at first low before treatment, increased to their highest levels during the first month, and then began to decrease during the second month until finally reaching and maintaining a relatively low level after 3–6 months. These results suggest that there is a relatively low level of MTB-specific monocytes in advanced and untreated patients. Further experiments show that MTB induces apoptosis in CD14⁺ cells, and the percentage of apoptotic monocytes dramatically decreases after treatment. Therefore, the relatively low level of MTB-specific monocytes is probably related to the apoptosis or necrosis of APCs due to live bacteria and their growth. The bactericidal effects of anti-TB drugs, as well as other unknown factors, would induce a peak value during the first month of treatment, and a relatively low level would be subsequently reached and maintained until all of the involved factors reached equilibrium. These tetramers have diagnostic potential and can provide valuable insights into the mechanisms of antigen presentation and its relationship with TB infection and latent TB infection.</p> </div

Percentage of early-apoptosis CD14⁺ cells from healthy donors or the continuously treated PTB patients.

<p>Apoptotic CD14⁺ cells were analyzed by flow cytometry using Annexin V plus PI staining <i>in vitro</i>. Annexin V⁺PI⁻ cells represent the early apoptotic populations. Healthy, healthy donors; untreated, untreated PTB patients; within 5 days, PTB patients who received regular anti-TB treatment within 5 days; 15 to 30 days, PTB patients received regular treatment for 15–30 days; More than 30 days: PTB patients received regular treatment for >30 days. The presented data indicate that the percentage of apoptotic cells dramatically decreased after treatment.</p

<i>In situ</i> detection of tetramer-bound MTB APCs using confocal laser-scanning microscopy.

<p>(A) The MTB antigen and peptide/HLA-DR were detected using <i>in situ</i> immunofluorescent staining with anti-MTB antibody and TCR tetramer, respectively. The nucleus is stained blue (panel 1), TCR tetramer is stained green (panel 2), and MTB antigen is stained red (panel 3). Panel 4 shows a merged image. (B) CD14 and peptide/HLA-DR were detected using i<i>n situ</i> immunofluorescent staining with anti-CD14 antibody and TCR tetramer, respectively. The nucleus is labeled in blue (panel 1), CD14 is labeled in green (panel 2), and the TCR tetramer is labeled in red (panel 3). Panel 4 shows a merged image. Lymph node and lung sections of active TB patients show co-staining in both (A) and (B), but no staining or only anti-CD14 antibody staining were observed in the lung and lymph node sections from non-PTB patients.</p

HLA-DRB1 alleles of 9 active PTB outpatients.

<p>HLA-DRB1 alleles of 9 active PTB outpatients.</p

HLA-DRB1 alleles of active PTB patients and the percentages of TCR tetramer-bound CD14⁺ monocytes in PBL samples.

a<p>The positivity rate indicates the median percentage of double-stained-positive monocytes in PBL samples from active PTB patients.</p

VDJ repertoire, CDR3 amino acid sequences of the α/β chains, and other related information regarding CD4⁺ TCR eu- and hu-tetramers.

<p>VDJ repertoire, CDR3 amino acid sequences of the α/β chains, and other related information regarding CD4⁺ TCR eu- and hu-tetramers.</p

Flow cytometric analysis of the binding of TCR tetramers to artificial APCs.

<p>(A) The X-axis indicates APCs with different HLA-DR alleles and Y-axis indicates the percentages of tetramer-positive APCs induced by different MTB-specific peptides (E7, E6, C5, and C14). On the X-axis, “none” indicates non-induced cells or cells that only expressed HLA-DR without the peptide listed on the Y-axis. (B) Examples of dot plots showing the binding of TCR tetramers with artificial APCs. Only the background stainings of the non-induced cells were shown (0.32% for eu and 0.23% for hu). Positive stainings by either the tetramers in cells expressing C14/HLA-DR following induction (10.90% in C14/HLA-DRB1*150101 stained with eu and 3.13% in C14/HLA-DRB1*08032 stained with hu), were observed. The expression of HLA-DR was confirmed by staining with the anti-HLA-DR antibody (L243-FITC). Because the binding of the TCR tetramers to peptide/HLA-DR complexes could be competitively blocked by L243, small cells appeared in the upper right quadrant of the dot plots.</p