Tireless individual swirling them around to kill bacteria (9)

I believe the answer is:

sterilise

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'them around to kill bacteria' is the definition.
I can't tell whether this definition defines the answer.

'tireless individual swirling' is the wordplay.
'individual' becomes 'i' (Roman numeral for one, ie individual).
'swirling' indicates anagramming the letters (letters get swirled around).
'tireless'+'i'='tirelessi'
'tirelessi' anagrammed gives 'STERILISE'.

Can you help me to learn more?

(Other definitions for sterilise that I've seen before include "Listerise (anag)" , "Disinfect" , "Make free from bacteria" , "Free from germs" , "Make free from micro-organisms, like surgeon's knife" .)

I've seen this clue in The Irish Times.

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