were there any organisms found in patient 42473's first microbiological mrsa screen test in the current hospital encounter?
select count(*)>0 from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 42473 and admissions.dischtime is null ) and microbiologyevents.spec_type_desc = 'mrsa screen' and microbiologyevents.org_name is not null order by microbiologyevents.charttime asc limit 1