while (my @row = $sth->fetchrow_array()) {
    s!$term!"<i>$term</i>"! for @row;
    # ...
}

##</code><code>##

my $rx = qr/\Q$term/;
while (my @row = $sth->fetchrow_array()) {
    s!$rx!"<i>$term</i>"! for @row;
    # ...
}