A Study to Identify and Characterise Bacteria Causing Chronic Cough Among Children in United Kingdom

Inclusion Criteria: * Subjects who the investigator believes that parent(s)/ legally acceptable representative can and will comply with the requirements of the protocol. * A male or female child between, and including, six to 72 months of age at the time of enrolment. * Written informed consent obtained from the parent(s)/ legally acceptable representative of the subject. * No antibiotic therapy within four weeks prior to the visit. * No cystic fibrosis or known major immunodeficiency such as agammaglobulinaemia, T cell deficiency or Human Immunodeficiency Virus / Acquired Immune Deficiency Syndrome. * No documented evidence or suspicion of gastroesophageal reflux disease. * No evidence of an upper viral respiratory infection four weeks prior to the visit. In addition, all subjects regarded as 'cases' must satisfy all the following criteria at study entry: * Persistent cough greater than eight weeks. * No response to five-day prednisolone treatment. * Chest X-ray showing no evidence of a lobar pneumonia or gross structural abnormality. In addition, all subjects regarded as 'controls' must satisfy the following criteria at study entry: * No respiratory symptoms four weeks prior to the visit. * No documented evidence or suspicion of lung disease upon physical examination. Exclusion Criteria: * Concurrently participating in another study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product. * Use of any investigational or non-registered product within 30 days prior to study procedures, or planned use during the study period. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination. * Child in care.