In:
Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 45, No. 12 ( 2001-12), p. 3355-3361
Abstract:
Escherichia coli ILT-1, Klebsiella pneumoniae ILT-2, and K. pneumoniae ILT-3 were isolated in May 1999 in Paris, France, from a rectal swab of a hospitalized 5-month-old girl. These isolates had a clavulanic acid-inhibited substrate profile that included expanded-spectrum cephalosporins. The MICs of cefotaxime were higher for E. coli ILT-1 and K. pneumoniae ILT-2 than for K. pneumoniae ILT-3, while the opposite was found for the MICs of ceftazidime. Genetic and biochemical analyses revealed that E. coli ILT-1 and K. pneumoniae ILT-2 produced the CTX-M-18 β-lactamase, while K. pneumoniae ILT-3 produced the CTX-M-19 β-lactamase. The amino acid sequence of the CTX-M-18 β-lactamase differed from that of the CTX-M-9 β-lactamase by an Ala-to-Val change at position 231, while CTX-M-19 possessed an additional Pro-to-Ser change at position 167 in the omega loop of Ambler class A enzymes. The latter amino acid substitution may explain the CTX-M-19-mediated hydrolysis of ceftazidime, which has not been reported for other CTX-M-type enzymes. The bla CTX-M-18 and bla CTX-M-19 genes were located on transferable plasmids that varied in size (ca. 60 and 50 kb, respectively) but that showed similar restriction patterns.
Type of Medium:
Online Resource
ISSN:
0066-4804
,
1098-6596
DOI:
10.1128/AAC.45.12.3355-3361.2001
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2001
detail.hit.zdb_id:
1496156-8
SSG:
12
SSG:
15,3
