instruction: what was the organism name of the last sputum, tracheal specimen microbiology test of patient 031-16123 in 09/2104?
response: SELECT microlab.organism FROM microlab WHERE microlab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '031-16123')) AND microlab.culturesite = 'sputum, tracheal specimen' AND STRFTIME('%y-%m', microlab.culturetakentime) = '2104-09' ORDER BY microlab.culturetakentime DESC LIMIT 1