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Volume 32, Number 6—June 2026
Synopsis
Emergence of Klebsiella pneumoniae Carbapenemase–Producing K. pneumoniae with Penicillin-Binding Protein 3 Insertions, Taiwan, 2021
Figure 2

Figure 2. Confocal laser scanning microscopy of Klebsiella pneumoniae carbapenemase (KPC)–producing K. pneumoniae with penicillin-binding protein 3 (PBP3) insertions with and without ATM treatment, Taiwan, 2021. Isolates on the left (ATM–) were not treated with aztreonam and isolates on the right (ATM+) were treated with 64 µg/mL ATM for 6 hours. A) KPC-producing K. pneumoniae with wild-type PBP3 showing elongated and filamentous PBP3 in ATM+, a typical feature of PBP3 inhibition. Isolate used (isolate no. LC6990) was collected from the same hospital as patient isolate in this study (B) and had similar sequence type 11, K locus 47, KPC-2–producing background, and aztreonam MIC (>128 µg/mL). B) KPC-producing K. pneumoniae with PBP3 insertion mutations from isolate LC1491 from this study. Note that ATM+ does not show PBP3 inhibition (filamentation) under the conditions of this experiment. Images were acquired using a 63× objective. ATM, aztreonam.