One-minute through test to distinguish lower respiratory infection by analysis of sputum; exploring the mechanisms

• Published in: BMC research notes Vol. 11; no. 1; p. 664
• Main Authors: Ramezani, Amir, Alipouratigh, Mahin, Eng, Lars, Turkina, Maria V, Lönn, Johanna, Theodorsson, Annette, Nayeri, Fariba
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12.09.2018; BioMed Central; BMC
• Subjects: Anti-Bacterial Agents; Antibiotics; Cell-free DNA; Color; Colorimetry; Cough; Deoxyribonucleic acid; Diagnosis; Dische’s test; DNA; DNA - analysis; Fever; Growth factors; Hepatocyte growth factor; Humans; Immune response; Infections; Neutrophil extracellular traps; Neutrophils; Pneumonia; Research Note; Respiratory infection; Respiratory tract infection; Respiratory tract infections; Respiratory Tract Infections - diagnosis; Risk factors; Sensitivity and Specificity; Sputum; Sputum - microbiology; Time Factors; Sweden; Cell-free DNA; Diagnosis; Dische’s test; Neutrophil extracellular traps; Respiratory infection
• ISSN: 1756-0500; 1756-0500
• DOI: 10.1186/s13104-018-3771-1

Cough and fever are the initial symptoms of lower respiratory infection. Severe cases might be fatal. Therefore, particularly in the non-equipped centers, the lack of diagnostic methods to identify the severe cases has resulted in overconsumption of antibiotics. On the basis of the knowledge about non-specific immune response at the site of injury, we developed a colorimetric dip-test that shows abrupt, sensitive and quite specific color change upon contact with sputum in the cases of lower respiratory infection. We further explored the mechanism of the test. We detected deoxyribonucleic acid (DNA) and hepatocyte growth factor in the sputum of patients that suffered from respiratory infection (n = 18). The results differed significantly (P < 0.0001) from age-matched patients (n = 18) with other respiratory disorders and highly correlated with the index-test results (Spearman Rank test = 0.84). DNA with a concentration more than 0.03 mg/ml induced a visible and stable color change on index-test within 1 min. The test recognized all of the cases with respiratory infection and the specificity was 72%. With a high negative predictive value. The index test detects, inter alia, cell-free DNA in sputum and might safely rule-out respiratory infection in 2/3 of cases that present symptoms of acute respiratory infection.