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Original Research

Efflux Pump AcrAB Confers Decreased Susceptibility to Piperacillin–Tazobactam and Ceftolozane–Tazobactam in Tigecycline-Non-Susceptible Klebsiella pneumoniae

, , , , , , & ORCID Icon show all
Pages 4309-4319 | Published online: 26 Nov 2020

Figures & data

Table 1 Primers Used in This Study

Table 2 Antimicrobial Susceptibility Patterns of the K. pneumoniae Clinical Parental Strains and Their Derivatives

Table 3 Genomic Changes of K2606 After Exposure to Tigecycline

Figure 1 Gene mutation and expression in TNSKP24, K2606 K2606-4, and K2606-16. (A) Mutations in ramR and the intergenic region of ramR-romA in K. pneumoniaeK2606 and its two derivatives when compared with K. pneumoniae MGH78578 (GenBank: CP000647.1). The arrow segments in the intergenic region of romR-romA are the inverted repeat (IR) sequences recognized by the RamR protein (24). The numbering system is based on the “t” prior to romA’s start codon ATG as the 194. Missense mutation (D77H) in ramR, and point mutation (C111T) in the intergenic region of ramR-romA was detected in K2606, K2606-4, and K2606-16, and an additional novel point mutation (C133T) was found between the palindromic repeats in the 2 derivatives. (B) and (C) Transcriptional expression (mean±standard deviation) of ramA, acrB, rarA, and oqxB in TNSKP24, K2606 K2606-4, and K2606-16.

Figure 1 Gene mutation and expression in TNSKP24, K2606 K2606-4, and K2606-16. (A) Mutations in ramR and the intergenic region of ramR-romA in K. pneumoniaeK2606 and its two derivatives when compared with K. pneumoniae MGH78578 (GenBank: CP000647.1). The arrow segments in the intergenic region of romR-romA are the inverted repeat (IR) sequences recognized by the RamR protein (24). The numbering system is based on the “t” prior to romA’s start codon ATG as the 194. Missense mutation (D77H) in ramR, and point mutation (C111T) in the intergenic region of ramR-romA was detected in K2606, K2606-4, and K2606-16, and an additional novel point mutation (C133T) was found between the palindromic repeats in the 2 derivatives. (B) and (C) Transcriptional expression (mean±standard deviation) of ramA, acrB, rarA, and oqxB in TNSKP24, K2606 K2606-4, and K2606-16.