TABLE 2

Amino acid substitutions in PBP3 in BLNAR and BLPACR isolatesa

GenotypeGroupNo. of strainsMIC (mg/liter)Amino acid substitution(s) in PBP3
AMPCTRCTXD350S357M377S385L389V436A437A502R517T532N526A530V547A554G555Y557V562N569A586S594A595I601E603
Low-BLNAR (n = 5)II11≤0.06≤0.06K
12≤0.060.25KSILG
12≤0.06≤0.06NIVKISSTT
11≤0.06≤0.06NIVKILSSTT
10.5≤0.06≤0.06NSVKILSSTTD
High-BLNAR (n = 47)III193.2b0.4b1.8bNNITFKILS
155b0.4b2.4bNNITFKILSSTTD
33.2b0.1b0.5bNNITFVK
34b0.2b0.6bNNITFKS
120.250.5NNITKILS
140.130.5NNITFTKIS
120.252NNITFKILG
1812NNITFAKILS
180.251NNITFKILSD
12≤0.060.13NNITFVKISD
120.130.25NNTVKISSTTD
High-BLNAR (n = 9)III-like12≤0.060.25NNITHSILN
45.7b0.3b5.7bNNITFHSIHS
120.130.5NNTHIEHSSTT
1160.252NNITFHITHLD
1160.52NNITFHIEHSSTT
140.251NNITFHIEHSSTTD
BLPACR (n = 2)III2>1280.25 or 0.51 or 2NNITFKILS
  • a Amino acid substitutions in the region from D350 to E603 in PBP3 were examined. Bold letters indicate amino acid substitutions classifying low- and high-BLNAR isolates and their groups. Amino acids at positions 379 to 381 and 512 to 514 were the Ser-Ser-Asn (SSN) motif and the Lys-Thr-Gly (KTG) motif, respectively. The high-BLNAR isolate SMHi90 was excluded because of its unique ftsI sequence (see Fig. S1 and S2). AMP, ampicillin; CTR, ceftriaxone; CTX, cefotaxime.

  • b Geometric mean.