Final answer:
The timing for collecting a sputum sample can vary, but it is often done early in the morning before breakfast or after nebulizer treatment. In John's case, the sputum sample was essential in identifying Legionella pneumophila as the cause of his symptoms after influenza was ruled out, allowing for the correct antibiotic treatment.
Step-by-step explanation:
The collection of a sputum sample is a common procedure in diagnosing respiratory infections such as influenza or Legionella pneumophila, the cause of Legionnaires' disease. Sputum collection typically happens early in the morning or after a nebulizer treatment, which is often before breakfast for outpatient settings or fasting patients. However, the timing can vary depending on the healthcare provider's instructions and the patient's condition. In a hospital setting, samples could be collected at different times, following specific protocols.
After chest radiography, and collecting blood and urine samples, a sputum sample may be analyzed for the presence of pathogens. The microscopic examination of an induced sputum sample can reveal the causative organism.
The clinical focus on the sputum sample involves sending it to a microbiology lab where the sample undergoes testing, which includes antimicrobial susceptibility testing (AST) to ensure appropriate antibiotic therapy is used. In cases like John's, where influenza tests came back negative, the sputum sample helped to identify an alternative diagnosis of Legionella pneumophila, demanding a shift in his treatment to include a specific antibiotic like levofloxacin.