what was the name of the organism at the last sputum test of patient 26886 on the first hospital encounter?
select microbiologyevents.org_name from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 26886 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) and microbiologyevents.spec_type_desc = 'sputum' and microbiologyevents.org_name is not null order by microbiologyevents.charttime desc limit 1