what was the last bronchial washings's microbiology test patient 91249 had in 01/2104?
select microbiologyevents.charttime from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 91249 ) and microbiologyevents.spec_type_desc = 'bronchial washings' and strftime('%y-%m',microbiologyevents.charttime) = '2104-01' order by microbiologyevents.charttime desc limit 1