Patient is treated with bit of cream, a germicide (10)
I believe the answer is:
antiseptic
'a germicide' is the definition.
(I've seen this before)
'patient is treated with bit of cream' is the wordplay.
'treated with' is an anagram indicator.
'bit of' suggests taking the first letters.
The initial letter of 'cream' is 'c'.
'patient'+'is'='patientis'
'patientis' mixed up with 'c' gives 'ANTISEPTIC'.
(Other definitions for antiseptic that I've seen before include "Preventing growth of microorganisms" , "treatment" , "Clinical" , "germicide" , "Preventing growth of, eg, bacteria" .)