Signs Of Lower Respiratory Tract Infection Research Articles

Genetic point‐of‐care diagnosis of Mycoplasma pneumoniae infection using LAMP assay

Mycoplasma pneumoniae (MP) is a major pathogen of lower respiratory tract infection (LRTI) in children. A rapid diagnostic method during the acute phase is required for the prescription of effective antibiotics. A prospective, single-centered study was conducted on community-acquired LRTI in children. We regarded the day of fever onset as the first day of illness. In part 1, we studied 191 patients with signs of LRTI. We compared diagnostic reliability using loop-mediated isothermal amplification (LAMP) assay and serological testing at the first visit. In part 2, we evaluated the clinical characteristics of 117 patients with positive LAMP assay. In part 1, 31 patients met the definite MP infection criteria. LAMP assay had a sensitivity of 96.8% and specificity of 100%, whereas enzyme immunoassay had a sensitivity of 38.7% and specificity of 76.9%, and particle agglutination test had a sensitivity of 19.4% and specificity of 93.1%. In part 2, of 106 patients with fever, 100 patients were diagnosed by the day 7 of illness. The diagnosis was made a mean of 3.5 ± 2.1 days after the onset of fever. LAMP assay had excellent sensitivity and specificity for the detection of acute MP infection at the first visit. This assay can diagnose MP infection during the very acute phase. LAMP assay is appropriate for genetic point-of-care diagnosis of MP infection in hospital laboratories.

Strong Association between Respiratory Viral Infection Early after Hematopoietic Stem Cell Transplantation and the Development of Life-Threatening Acute and Chronic Alloimmune Lung Syndromes

Alloimmune lung syndromes (allo-LS), including idiopathic pneumonia syndrome, bronchiolitis obliterans syndrome, and bronchiolitis obliterans organizing pneumonia, are severe complications after hematopoietic stem cell transplantation (HSCT). In our cohort of 110 pediatric patients, 30 had allo-LS (27.3%), 18 with ideopathic pneumonia syndrome and 12 with bronchiolitis obliterans syndrome. Multivariate analysis showed that respiratory viral infection early after HSCT is an important predictor for the development of allo-LS (P <.0001). This was true for all viruses tested. In multivariate analysis, allo-LS was the only predictor for higher mortality (P = .04). Paradoxically, prolonged administration of immunosuppressive agents because of acute graft-versus-host disease had a protective effect on the development of allo-LS (P = .004). We hypothesize that early infection of the respiratory tract with a common cold virus makes the lungs a target for alloimmunity.

Chlamydia trachomatis lower respiratory tract infection in infants.

Chlamydia trachomatis may be an important cause of lower respiratory tract infection (LRTI) in infants born to mothers amongst whom there is a high prevalence of sexually transmitted disease. A study of 100 ambulatory infants with signs of LRTI in South Africa showed that 6% had C. trachomatis infection. The majority of the infected infants had received chloramphenicol eye ointment as prophylaxis. Half had previously visited a health facility for the same illness but the infection has been misdiagnosed. Infants with C. trachomatis infection were According to the Centers for Disease Control (CDC) guidelines, 85% were younger than uninfected infants (mean (SD) age of 3.8 weeks (3.2) vs 8.7 weeks (5.4); p=0.03). Clinical signs significantly associated with chlamydial infection were the presence of eye discharge (p = 0.02) or conjunctivitis (p = 0.01). There was a greater rate of rhinorrhoea (p = 0.06) and wheeze (p = 0.03) amongst patients without chlamydial infection. H. influenzae, M. catarrhalis, S. pneumoniae, S. aureus and N. gonorrhoeae were cultured from five different patients infected with chlamydia. The majority of infants with chlamydial infection had mild disease requiring only outpatient anti- biotic therapy.