what was the name of the organism detected in patient 71091's last urine microbiology test until 2 months ago?
select microbiologyevents.org_name from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 71091 ) and microbiologyevents.spec_type_desc = 'urine' and microbiologyevents.org_name is not null and datetime(microbiologyevents.charttime) <= datetime(current_time,'-2 month') order by microbiologyevents.charttime desc limit 1