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Table 4 Minimal inhibitory concentrations to penicillin of Streptococcus pneumoniae mutants and transformants

From: Whole genome sequencing of penicillin-resistant Streptococcus pneumoniae reveals mutations in penicillin-binding proteins and in a putative iron permease

Strain or transformant Description MIC to PG (μg/ml)a
R6 Wild type 0.023
CCRI1974 S. pneumoniae, sensitive clinical isolate 0.023
R6M1 R6 clone selected in vitro for PG resistance 2.0
R6M2 R6 clone selected in vitro for PG resistance 2.0
1974M1 1974 clone selected in vitro for PG resistance 2.0
1974M2 1974 clone selected in vitro for PG resistance 2.0
CP1250 S. pneumoniae that contains a spontaneous mutation in the rpsL gene that confers resistance to SM  
R62x-M1 R6-WT transformed with pbp2x PCR fragments from R6M1 (contains all three missense mutations present in PBP2x of R6M1) 0.06
R62x-M2 R6-WT transformed with pbp2x PCR fragments from R6M2 (contains just three mutations - Q281P, A369V, R384G - out of five mutations present in PBP2x of R6M2) 0.06
R62x2b-M1 R62x-M1 transformed with pbp2b PCR fragments from R6M1 so all missense mutations present in PBP2b of R6M1 transformed into this transformant 0.125
R62x2b-M2 R62x-M2 transformed with pbp2b PCR fragments from R6M2 so all missense mutations present in PBP2b of R6M2 transformed into this transformant 0.125
R62x2b-M2, 1a::Janus R62x2b-M2 knocked out in pbp1a by Janus cassette, KMRSMS 0.125
R6SmR, 2x2b1a-M2, R62x2b-M2, 1a::Janus subjected to second step transformation with pbp1a of the Janus cassette with pbp1a of R6M2, KMSSMR 0.125
R6SmR, 2x2b1a,spr1178-M2, R62x2b1a-M2 transformed with spr1178 PCR fragments from R6M2 (contains a Q28* nonsense mutation in spr1178), SMR 0.125
R62x2b,spr1254-M2 R62x2b-M2 transformed with pstB PCR fragment from R6M2 (contains a T205I mutation in PstB) 0.125
R62x2b, spr1254, spr1178-M2 R62x2b-M2 transformed with spr1178 and pstB PCR fragments from R6M2 (contains the substitutions Q28* in spr1178 and T205I in PstB) 0.125
R6M1SmR,1a-WT R6M1 co-transformed with a pbp1a PCR fragment from R6-WT and a rpsL streptomycin resistance marker, SMR 1.0
R6ko in spr1178 R6-WT knocked out in spr1178, CMR 0.023
R6ko in spr1254 R6-WT knocked out in spr1254, KMR 0.023
R6spr1888::janus R6-WT knocked out in spr1888 by Janus cassette, KMRSMS 0.023
  1. aResults are the average of at least three independent measurements. Asterisks indicate nonsense mutations. PG, penicillin; KM, kanamycin; SM, streptomycin.