###HUMAN: what was the number of patients that were tested since 5 years ago for sputum, tracheal specimen microbiology?, ###ASSISTANT: SELECT COUNT(DISTINCT patient.uniquepid) FROM patient WHERE patient.patientunitstayid IN (SELECT microlab.patientunitstayid FROM microlab WHERE microlab.culturesite = 'sputum, tracheal specimen' AND DATETIME(microlab.culturetakentime) >= DATETIME(CURRENT_TIME(), '-5 year'))