We randomly allocated infants to receive injectable procaine benzylpenicillin-gentamicin for @ days ( group A , reference group ) ; injectable gentamicin and oral amoxicillin for @ days ( group B ) ; injectable procaine benzylpenicillin-gentamicin for @ days , then oral amoxicillin for @ days ( group C ) ; or injectable gentamicin for @ days and oral amoxicillin for @ days ( group D ) .