since 08/2101 what was patient 59002's last microbiology test time?
select microbiologyevents.charttime from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 59002 ) and strftime('%y-%m',microbiologyevents.charttime) >= '2101-08' order by microbiologyevents.charttime desc limit 1