title: Atypical Pneumonia - Screening in a Tertiary Care Centre.
abstract: BACKGROUND
  Pneumonia is one of the leading infectious causes of mortality and morbidity worldwide. Atypical respiratory pathogens account for 30 - 40% of these infections. The three most important atypical pathogens are Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila.
  
  
  OBJECTIVE
  To screen for atypical pathogens as cause for community acquired pneumonia.
  
  
  METHODS
  A cross-sectional study was done with 107 patients who had clinical suspicion of atypical pneumonia. The presence of atypical pathogens Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila were screened from the patient's sample. Respiratory samples in the form of sputum, Broncheoalveolar lavage and Non- Broncheoalveolar lavage were used for cultivation of Mycoplasma pneumoniae and Legionella pneumophila. Urine specimen was used for the detection of Legionella antigen. Serum samples were used for the detection of Mycoplasma pneumoniae IgM and Chlamydophila pneumoniae IgM antibodies.
  
  
  RESULTS
  Among the 107 samples screened, 13(12.1%) were positive for antibodies against atypical pathogens. Out of which 7(6.5%) had IgM antibodies against Mycoplasma pneumoniae and the rest 6(5.6%) had Chlamydophila pneumoniae IgM antibodies. All the samples were culture negative for Mycoplasma pneumoniae and Legionella pneumophila. Urinary antigen detection for Legionella pneumophila was also negative in patients.
  
  
  CONCLUSIONS
  Atypical pathogens should also be considered routinely as a cause of lower respiratory tract infections, especially Chlamydia pneumoniae and Mycoplasma pneumoniae in our country. Serological diagnosis by ELISA can be adopted for determining the infections by atypical pathogens as cultivation is difficult and also requires special media and prolonged incubation. This may not be feasible for many laboratories. Early diagnosis and treatment will reduce the complications.
authors.affiliation: Post Graduate Student, Department of Microbiology, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University , Porur, Chennai, India .
authors.forename: Aruna
authors.initials: A
authors.lastname: Dorairaj
authors.affiliation: Associate Professor, Department of Microbiology, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University , Porur, Chennai, India .
authors.forename: Sridharan Sathyamoorthy
authors.initials: SS
authors.lastname: Kopula
authors.affiliation: Associate Professor, Department of Microbiology, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University , Porur, Chennai, India .
authors.forename: Kennedy
authors.initials: K
authors.lastname: Kumar
keywords: Atypical pathogens; Methylene blue glucose biphasic medium; PPLO urinary antigen