in 05/2103 when patient 73362 first got a microbiology test?
select microbiologyevents.charttime from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 73362 ) and strftime('%y-%m',microbiologyevents.charttime) = '2103-05' order by microbiologyevents.charttime asc limit 1