scholarly journals Transferable class C beta-lactamases in Escherichia coli strains isolated in Greek hospitals and characterization of two enzyme variants (LAT-3 and LAT-4) closely related to Citrobacter freundii AmpC beta- lactamase

1998 ◽  
Vol 42 (4) ◽  
pp. 419-425 ◽  
Author(s):  
M. Gazouli ◽  
L. S. Tzouvelekis ◽  
A. C. Vatopoulos ◽  
E. Tzelepi
Keyword(s):  
Escherichia Coli ◽  
Citrobacter Freundii ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Class C ◽  
Greek Hospitals

Transferable cefoxitin resistance in enterobacteria from Greek hospitals and characterization of a plasmid-mediated group 1 beta-lactamase (LAT-2).

1996 ◽  
Vol 40 (7) ◽  
pp. 1736-1740 ◽  
Author(s):  
M Gazouli ◽  
L S Tzouvelekis ◽  
E Prinarakis ◽  
V Miriagou ◽  
E Tzelepi
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Citrobacter Freundii ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Greek Hospitals ◽  
Group 1

Cefoxitin resistance in Klebsiella pneumoniae from Escherichia coli strains isolated in Greek hospitals was found to be due to the acquisition of similar plasmids coding for group 1 beta-lactamases. The plasmids were not self-transferable but were mobilized by conjugative plasmids. These elements have also been spread to Enterobacter aerogenes. The most common enzyme was a Citrobacter freundii-derived cephalosporinase (LAT-2) which differed from LAT-1 by three amino acids.

scholarly journals Construction and characterization of an OHIO-1 beta-lactamase bearing Met69Ile and Gly238Ser mutations.

1997 ◽  
Vol 41 (9) ◽  
pp. 1940-1943 ◽  
Author(s):  
R A Bonomo ◽  
J R Knox ◽  
S D Rudin ◽  
D M Shlaes
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Beta Lactamase ◽  
Beta Lactams ◽  
Beta Lactamases ◽  
Class A ◽  
Influence Activity

Amino acid changes that influence activity and resistance to beta-lactams and beta-lactamase inhibitors were explored by constructing the Gly238Ser and Met69Ile-Gly238Ser mutants of the OHIO-1 beta-lactamase, a class A enzyme of the SHV family. The Km values of cefotaxime and ceftazidime for OHIO-1 and Met69Ile beta-lactamases were > or = 500 microM. The Km of cefotaxime for the Gly238Ser beta-lactamase was 26 microM, and that of ceftazidime was 105 microM. The Km of cefotaxime for the Met69Ile-Gly238Ser beta-lactamase was 292 microM, and that of ceftazidime was 392 microM. For the beta-lactamase inhibitors clavulanate and sulbactam, the apparent Ki values for the Met69Ile-Gly238Ser enzyme were 0.03 and 0.15 microM, respectively. Relative Vmax values indicate that the Met69Ile-Gly238Ser mutant of the OHIO-1 beta-lactamase possesses cephalosporinase activity similar to that of the Gly238Ser mutant but diminished penicillinase activity. In an Escherichia coli DH5alpha strain that possesses a Met69Ile beta-lactamase of the OHIO-1 family, the added Gly238Ser mutation resulted in a phenotype with qualities that confer resistance to expanded-spectrum cephalosporins and, to a lesser extent, beta-lactamase inhibitors.

scholarly journals Comparative characterization of the cephamycinase blaCMY-1 gene and its relationship with other beta-lactamase genes.

1996 ◽  
Vol 40 (8) ◽  
pp. 1926-1930 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
R Wilhelm ◽  
Y Chong
Keyword(s):  
Enterobacter Cloacae ◽  
Citrobacter Freundii ◽  
Beta Lactamase ◽  
Phenotypic Characteristics ◽  
Beta Lactamases ◽  
Its Gene ◽  
Relationship Of ◽  
The Relationship ◽  
Relevant Class

A plasmidic beta-lactamase which hydrolyzed cephamycins was first detected and reported in 1989. At that time its description was restricted to phenotypic characteristics. We analyzed nucleotide sequence of its gene and explored it genetic relationship with other bla genes. The deduced amino acid sequence of the blaCMY-1 product was compared with those of other known plasmidic cephamycinases and of chromosomal AmpC beta-lactamases. The results indicate that the relationship of CMY-1 is closest to MOX-1 among the plasmidic cephamycinases and to AmpC of Pseudomonas aeruginosa among the chromosomal cephalosporinases. We conclude that the plasmidic cephamycinases described up to now may be classified into three families, as follows: CMY-1, MOX-1, and FOX-1 with AmpC of P. aeruginosa; CMY-2, BIL-1 and LAT-1 with AmpC of Citrobacter freundii; and MIR-1 with AmpC of Enterobacter cloacae. Plasmidic cephamycinases are now recognized as clinically relevant class C beta-lactamases.

scholarly journals The acyl-enzyme mechanism of β-lactamase action. The evidence for class C β-lactamases

1982 ◽  
Vol 207 (2) ◽  
pp. 315-322 ◽  
Author(s):  
V Knott-Hunziker ◽  
S Petursson ◽  
S G Waley ◽  
B Jaurin ◽  
T Grundström
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Enzyme Mechanism ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Escherichia Coli K12 ◽  
Rate Determining Step ◽  
Class C ◽  
Hydrolysis Of

Methanol or ethanol can replace water in the action of certain chromosomal beta-lactamases on benzylpenicillin: the products are alpha-methyl or alpha-ethyl benzylpenicilloate. The beta-lactamases were from a mutant of Pseudomonas aeruginosa 18S that produces the enzyme constitutively [Flett, Curtis & Richmond (1976) J. Bacteriol. 127, 1585-1586; Berks, Redhead & Abraham (1982) J. Gen. Microbiol. 128, 155-159] and from Escherichia coli K12 (the ampC beta-lactamase) [Lindström, Boman & Steele (1970) J. Bacteriol. 101, 218-231]. The variation of the rates of alcoholysis and hydrolysis with concentration of alcohol show that the rate-determining step is breakdown of an intermediate. This intermediate is likely to be the acyl-enzyme. The esters, alpha-methyl or alpha-ethyl benzylpenicilloate, are themselves substrates for the Pseudomonas beta-lactamase, benzylpenicilloic acid being formed. Thus this beta-lactamase can be an esterase. The kinetics for the hydrolysis of cloxacillin by the Pseudomonas beta-lactamase are consistent with the acyl-enzyme, formed by acylation of serine-80, being an intermediate in the overall hydrolysis.

scholarly journals Sequence and comparative analysis of three Enterobacter cloacae ampC β-lactamase genes and their products

1988 ◽  
Vol 250 (3) ◽  
pp. 753-760 ◽  
Author(s):  
M Galleni ◽  
F Lindberg ◽  
S Normark ◽  
S Cole ◽  
N Honore ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Comparative Analysis ◽  
Amino Acid ◽  
Enterobacter Cloacae ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Citrobacter Freundii ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
High Degree

The sequences of three Enterobacter cloacae ampC beta-lactamase genes have been determined. The deduced amino acid sequences are very similar: out of a total of 361 residues, only eight positions were found to be variable, and several mutations yielded residues with very similar properties. The kinetic properties of two of the enzymes were not significantly different. The three enzymes also exhibited a high degree of homology (greater than 70%) with the ampC beta-lactamases of Escherichia coli K12 and Citrobacter freundii, confirming the homogeneity of class-C beta-lactamases.

scholarly journals Characterization of the plasmidic beta-lactamase CMY-2, which is responsible for cephamycin resistance.

1996 ◽  
Vol 40 (1) ◽  
pp. 221-224 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
H Giamarellou
Keyword(s):  
Amino Acids ◽  
Klebsiella Pneumoniae ◽  
Open Reading Frame ◽  
Its Sequence ◽  
Citrobacter Freundii ◽  
Beta Lactamase ◽  
Reading Frame ◽  
Class C

The phenotype of Klebsiella pneumoniae HEL-1 indicates a plasmidic cephamycinase gene (blaCMY-2). Its sequence shows one open reading frame coding for a protein of 381 amino acids. CMY-2 is classified as class C beta-lactamase that is closely related to the plasmidic enzymes BIL-1 and LAT-1 and the chromosomal AmpC of Citrobacter freundii. The blaCMY-2 gene possibly was translocated onto a plasmid of C. freundii which spread to K. pneumoniae.

scholarly journals Characterization of the 6'-N-aminoglycoside acetyltransferase gene aac(6')-Im [corrected] associated with a sulI-type integron.

1997 ◽  
Vol 41 (2) ◽  
pp. 314-318 ◽  
Author(s):  
E Hannecart-Pokorni ◽  
F Depuydt ◽  
L de wit ◽  
E van Bossuyt ◽  
J Content ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Resistance Gene ◽  
Citrobacter Freundii ◽  
Gram Negative ◽  
Gene Environment ◽  
Insert Region ◽  
Klebsiella Spp

The amikacin resistance gene aac(6')-Im [corrected] from Citrobacter freundii Cf155 encoding an aminoglycoside 6'-N-acetyltransferase was characterized. The gene was identified as a coding sequence of 521 bp located down-stream from the 5' conserved segment of an integron. The sequence of this aac(6')-Im [corrected] gene corresponded to a protein of 173 amino acids which possessed 64.2% identity in a 165-amino-acid overlap with the aac(6')-Ia gene product (F.C. Tenover, D. Filpula, K.L. Phillips, and J. J. Plorde, J. Bacteriol. 170:471-473, 1988). By using PCR, the aac(6')-Im [corrected] gene could be detected in 8 of 86 gram-negative clinical isolates from two Belgian hospitals, including isolates of Citrobacter, Klebsiella spp., and Escherichia coli. PCR mapping of the aac(6')-Im [corrected] gene environment in these isolates indicated that the gene was located within a sulI-type integron; the insert region is 1,700 bases long and includes two genes cassettes, the second being ant (3")-Ib.

Sign in / Sign up

Export Citation Format

Share Document