This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kimura, S. Articles by Yamaguchi, K. Search for Related Content PubMed PubMed Citation Articles by Kimura, S. Articles by Yamaguchi, K.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, May 2004, p. 1454-1460, Vol. 48, No. 5
0066-4804/04/$08.00+0     DOI: 10.1128/AAC.48.5.1454-1460.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Role of a Mutation at Position 167 of CTX-M-19 in Ceftazidime Hydrolysis

Department of Microbiology, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 1438540,¹ Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Mishima-gun, Osaka 6188503, Japan²

Received 15 July 2003/ Returned for modification 28 September 2003/ Accepted 30 December 2003

CTX-M-19 is a recently identified ceftazidime-hydrolyzing extended-spectrum ß-lactamase, which differs from the majority of CTX-M-type ß-lactamases that preferentially hydrolyze cefotaxime but not ceftazidime. To elucidate the mechanism of ceftazidime hydrolysis by CTX-M-19, the ß-lactam MICs of a CTX-M-19 producer, and the kinetic parameters of the enzyme were confirmed. We reconfirmed here that CTX-M-19 is also stable at a high enzyme concentration in the presence of bovine serum albumin (20 µg/ml). Under this condition, we obtained more accurate kinetic parameters and determined that cefotaxime (k_cat/K_m, 1.47 x 10⁶ s^–1 M^–1), cefoxitin (k_cat/K_m, 62.2 s^–1 M^–1), and aztreonam (k_cat/K_m, 1.34 x 10³ s^–1 M^–1) are good substrates and that imipenem (k₊₂/K, 1.20 x 10² s^–1 M^–1) is a poor substrate. However, CTX-M-18 and CTX-M-19 exhibited too high a K_m value (2.7 to 5.6 mM) against ceftazidime to obtain their catalytic activity (k_cat). Comparison of the MICs with the catalytic efficiency (k_cat/K_m) of these enzymes showed that some ß-lactams, including cefotaxime, ceftazidime, and aztreonam showed a similar correlation. Using the previously reported crystal structure of the Toho-1 ß-lactamase, which belongs to the CTX-M-type ß-lactamase group, we have suggested characteristic interactions between the enzymes and the ß-lactams ceftazidime, cefotaxime, and aztreonam by molecular modeling. Aminothiazole-bearing ß-lactams require a displacement of the aminothiazole moiety due to a severe steric interaction with the hydroxyl group of Ser167 in CTX-M-19, and the displacement affects the interaction between Ser130 and the acidic group such as carboxylate and sulfonate of ß-lactams.

This article has been cited by other articles:

• Novais, A., Canton, R., Coque, T. M., Moya, A., Baquero, F., Galan, J. C. (2008). Mutational Events in Cefotaximase Extended-Spectrum {beta}-Lactamases of the CTX-M-1 Cluster Involved in Ceftazidime Resistance. Antimicrob. Agents Chemother. 52: 2377-2382 [Abstract] [Full Text]  
• Stepanova, M. N., Pimkin, M., Nikulin, A. A., Kozyreva, V. K., Agapova, E. D., Edelstein, M. V. (2008). Convergent In Vivo and In Vitro Selection of Ceftazidime Resistance Mutations at Position 167 of CTX-M-3 {beta}-Lactamase in Hypermutable Escherichia coli Strains. Antimicrob. Agents Chemother. 52: 1297-1301 [Abstract] [Full Text]  
• Bae, I. K., Lee, B. H., Hwang, H. Y., Jeong, S. H., Hong, S. G., Chang, C. L., Kwak, H.-S., Kim, H. J., Youn, H. (2006). A novel ceftazidime-hydrolysing extended-spectrum {beta}-lactamase, CTX-M-54, with a single amino acid substitution at position 167 in the omega loop. J Antimicrob Chemother 58: 315-319 [Abstract] [Full Text]  
• Delmas, J., Robin, F., Carvalho, F., Mongaret, C., Bonnet, R. (2006). Prediction of the Evolution of Ceftazidime Resistance in Extended-Spectrum {beta}-Lactamase CTX-M-9. Antimicrob. Agents Chemother. 50: 731-738 [Abstract] [Full Text]  
• Ishii, Y., Kimura, S., Alba, J., Shiroto, K., Otsuka, M., Hashizume, N., Tamura, K., Yamaguchi, K. (2005). Extended-Spectrum {beta}-Lactamase-Producing Shiga Toxin Gene (stx1)-Positive Escherichia coli O26:H11: a New Concern. J. Clin. Microbiol. 43: 1072-1075 [Abstract] [Full Text]