ADJ.
against, bacterial
FIRST-LINE + NOUN
defense, manager, treatment
adj
Of first resort.
The embankment was the first-line defense against the flood.
Of prime quality or importance.
At the lowermost supervisory level.
first-line manager
Police sergeant is a first-line position.
Penicillin is a first-line treatment for bacterial infections, but doesn't work against viruses.