what was the the organism name found in the first pleural fluid test of patient 17398 until 40 months ago?
select microbiologyevents.org_name from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 17398 ) and microbiologyevents.spec_type_desc = 'pleural fluid' and microbiologyevents.org_name is not null and datetime(microbiologyevents.charttime) <= datetime(current_time,'-40 month') order by microbiologyevents.charttime asc limit 1