Article Figures & Data
Figures
- FIG. 1.
Genetic environment of blaKLUA-1 gene encoding the β-lactamase produced by K. ascorbata strain CIP 82.95T. The regions surrounding the chromosomal blaKLUA-1 gene and the sequences adjacent to the plasmidic genes encoding β-lactamases CTX-M-2, CTX-M-4, CTX-M-5, CTX-M-6, CTX-M-7, and Toho-1 (2, 10, 11, 23) were compared. The RTR sequence and tnpA correspond to the right terminal repeat and transposase A, respectively, which are typical of ISEcp1.
Tables
- TABLE 1.
MICs of 12 β-lactams for the 12 clinical K. ascorbata isolates, recipient strain E. coli XL-1, and the E. coli XL-1 transformant producing KLUA-1
β-Lactam(s)a No. of isolates for which MIC (μg/ml) was: MIC (μg/ml) for E. coli XL-1 recipient <0.03 0.06 0.125 0.25 0.5 1 2 4 8 16 32 64 128 R+ R− Amoxicillin 1 1 4 4 2 >128 4 Amoxicillin + CA 3b 3 4 2 1 1 Ticarcillin 2 3 4 3 >128 0.5 Ticarcillin + CA 5b 2 4 1 4 0.125 Piperacillin 1 4 4 3 128 1 Piperacillin + TZ 4b 3 3 1 1 2 0.12 Cephalothin 2 7 3 >128 0.5 Cefuroxime 1 6 5 64 1 Cefoxitin 1 4 4 3 2 1 Cefotaxime 3 7 2 128 <0.03 Ceftriaxone 2 6 4 14 <0.03 Ceftazidime 6 5 1 4 0.06 Cefepime 9 2 1 4 <0.03 Aztreonam 4 6 2 8 0.12 Imipenem 1 6 5 0.25 <0.03 - TABLE 2.
Kinetic constants (Vmax, Km) of β-lactamase produced by K. ascorbata strain CIP 82. 95Ta
Substrate Vmax (relative) Km (μM) Vmax/Km (relative) Benzylpenicillin 100 17.5 100 Ticarcillin 7.5 10 13 Cephalothin 1,100 141 136 Cefuroxime 80 35 40 Cefotaxime 110 375 5.1 Ceftazidime <0.1 50 <0.04 Aztreonam 0.3 105 0.06 Cefoxitin <0.1 110 <0.02 ↵ a V max was expressed relative to the Vmax for benzylpenicillin (which was set at 100%).
- TABLE 3.
Genotypic characterization of β-lactamase contents of K. ascorbata strains and β-lactamase pIs
Strain pI Result of PCR with primer(s): Gene Genbank accession no. MA1-MA2 (208-751 bp; 543 bp) MA3 (1-430 bp; 429 bp) MA4 (461-883 bp; 422 bp) CIP 82.95T 8.0 + + + bla KLUA-1 AJ272538 IP 15.79 8.4 + + + bla KLUA-2 AJ251722 IP 5.79 8.0 + + + bla KLUA-3 AJ427461 IP 8.79 8.0 + + + bla KLUA-4 AJ427462 IP 12.79 8.0 + + + bla KLUA-5 AJ427463 SL Ka99 6.9 − − − IP 2.89 6.9 − − − IP 3.89 8.0 + + + bla KLUA-8 AJ427465 TN Ka01 8.4 + + + bla KLUA-9 AJ427466 IP 43.50 8.0 + + + bla KLUA-10 AJ427467 IP 4450.94 8.4 + + + bla KLUA-11 AJ427468 IP 684.74 8.4 + + + bla KLUA-12 AJ427469 - TABLE 4.
Identities of amino acid sequences of K. ascorbata β-lactamases and CTX-M, Toho, UOE β-lactamases
Enzyme(s) Range % identity (reference) with clusters including: KLUA-1, -2, -3, -4, -5, -8, -9, -10, -11, and -12 (this work) CTX-M-1, -3, -10, -11, and -12 and UOE-1 (13, 18, 23a) CTX-M-2, -4, -5, -6, and -7 and Toho-1 (3, 10, 11, 23) CTX-M-9, -13, -14, and -15 and UOE-2 (21b) Toho-2 (15) CTX-M-8 (2) KLUA-1, -2, -3, -4, -5, -8, -9, -10, -11, and -12 96-100 77-82 95-100 78-81 68-71 82-84 CTX-M-1, -3, -10, -11, and -12 and UOE-1 98-100 77-81 79-80 70-71 80-82 CTX-M-2, -4, -5, -6, and -7 and Toho-1 97-100 78-81 68-71 81-84 CTX-M-9, -13, -14, and -15 and UOE-2 99-100 87-88 85-86 Toho-2 100 75 CTX-M-8 100
