SYNPH2515 6550 1 42 poly linker SYNPH2515 6550 223 228 macrolide-lincosamide-streptogramin B resistance SYNPH2515 6550 1451 1505 tetracycline resistance SYNPH2515 6550 4898 4903 ampicillin resistance SYNPH2515 6550 6029 6539 RNA primer