scholarly journals Survey of Enterobacteriaceae Producing Extended-Spectrum β-Lactamases in a Slovak Hospital: Dominance of SHV-2a and Characterization of TEM-132

2005 ◽  
Vol 49 (7) ◽  
pp. 3066-3069 ◽  
Author(s):  
Martina Zarnayová ◽  
Eliane Siebor ◽  
André Péchinot ◽  
Jean-Marie Duez ◽  
Helena Bujdáková ◽  
...  
Keyword(s):  
Amino Acid ◽  
Kinetic Properties ◽  
Amino Acid Substitutions ◽  
Extended Spectrum

ABSTRACT Eighty-five extended-spectrum β-lactamase-producing Enterobacteriaceae from a Slovak hospital have been studied. SHV-2a was predominant, but other variants have been detected, namely, SHV-5, SHV-12, TEM-12, TEM-15, and TEM-132, which differed from TEM-1 by amino acid substitutions R164H, E240K, and I173V and had kinetic properties similar to those of TEM-28.

scholarly journals Diversity of TEM Mutants in Proteus mirabilis

1999 ◽  
Vol 43 (11) ◽  
pp. 2671-2677 ◽  
Author(s):  
R. Bonnet ◽  
C. De Champs ◽  
D. Sirot ◽  
C. Chanal ◽  
R. Labia ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Proteus Mirabilis ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
First Report ◽  
Conjugative Plasmids ◽  
Extended Spectrum ◽  
Nucleotide Mutation

ABSTRACT In a survey of resistance to amoxicillin among clinical isolates ofProteus mirabilis, 10 TEM-type β-lactamases were characterized: (i) the well-known penicillinases TEM-1 and TEM-2, the extended-spectrum β-lactamases (ESBLs) TEM-3 and TEM-24, and the inhibitor-resistant TEM (IRT) TEM-44 and (ii) five novel enzymes, a penicillinase TEM-57 similar to TEM-1, an ESBL TEM-66 similar to TEM-3, and three IRTs, TEM-65, TEM-73, and TEM-74. The penicillinase TEM-57 and the ESBL TEM-66 differed from TEM-1 and TEM-3, respectively, by the amino acid substitution Gly-92→Asp (nucleotide mutation G-477→A). This substitution could have accounted for the decrease in pIs (5.2 for TEM-57 and 6.0 for TEM-66) but did not necessarily affect the intrinsic activities of these enzymes. The IRT TEM-65 was an IRT-1-like IRT (Cys-244) related to TEM-2 (Lys-39). The two other IRTs, TEM-73 and TEM-74, were related to IRT-1 (Cys-244) and IRT-2 (Ser-244), respectively, and harbored the amino acid substitutions Leu-21→Phe and Thr-265→Met. In this study, the ESBLs TEM-66, TEM-24, and TEM-3 were encoded by large (170- to 180-kb) conjugative plasmids that exhibited similar patterns after digestion and hybridization with the TEM and AAC(6′)I probes. The three IRTs TEM-65, TEM-73, and TEM-74 were encoded by plasmids that ranged in size from 42 to 70 kb but for which no transfer was obtained. The characterization of five new plasmid-mediated TEM-type β-lactamases and the first report of TEM-24 in P. mirabilis are evidence of the wide diversity of β-lactamases produced in this species and of its possible role as a β-lactamase-encoding plasmid reservoir.

scholarly journals TEM-121, a Novel Complex Mutant of TEM-Type β-Lactamase from Enterobacter aerogenes

2004 ◽  
Vol 48 (12) ◽  
pp. 4528-4531 ◽  
Author(s):  
Laurent Poirel ◽  
Hedi Mammeri ◽  
Patrice Nordmann
Keyword(s):  
Amino Acid ◽  
Kinetic Parameters ◽  
Clavulanic Acid ◽  
Clinical Isolate ◽  
Amino Acid Change ◽  
Enterobacter Aerogenes ◽  
Kinetic Properties ◽  
Amino Acid Substitutions ◽  
Extended Spectrum ◽  
Novel Complex

ABSTRACT Enterobacter aerogenes clinical isolate LOR was resistant to penicillins and ceftazidime but susceptible to cefuroxime, cephalothin, cefoxitin, cefotaxime, ceftriaxone, and cefepime. PCR and cloning experiments from this strain identified a novel TEM-type β-lactamase (TEM-121) differing by five amino acid substitutions from β-lactamase TEM-2 (Glu104Lys, Arg164Ser, Ala237Thr, Glu240Lys, and Arg244Ser) and by only one amino acid change from the extended-spectrum β-lactamase (ESBL) TEM-24 (Arg244Ser), with the last substitution also being identified in the inhibitor-resistant β-lactamase IRT-2. Kinetic parameters indicated that TEM-121 hydrolyzed ceftazidime and aztreonam (like TEM-24) and was inhibited weakly by clavulanic acid and strongly by tazobactam. Thus, TEM-121 is a novel complex mutant TEM β-lactamase (CMT-4) combining the kinetic properties of an ESBL and an inhibitor-resistant TEM enzyme.

scholarly journals Construction and Characterization of Mutants of the TEM-1 β-Lactamase Containing Amino Acid Substitutions Associated with both Extended-Spectrum Resistance and Resistance to β-Lactamase Inhibitors

1999 ◽  
Vol 43 (8) ◽  
pp. 1881-1887 ◽  
Author(s):  
Paul D. Stapleton ◽  
Kevin P. Shannon ◽  
Gary L. French
Keyword(s):  
Amino Acid ◽  
Site Directed Mutagenesis ◽  
Amino Acid Substitutions ◽  
Extended Spectrum ◽  
Double Substitution ◽  
Inhibitor Resistance ◽  
Reduced Activity ◽  
Hybrid Enzymes ◽  
Increased Susceptibility

ABSTRACT Extended-spectrum TEM β-lactamases (ESBLs) do not usually confer resistance to β-lactamase inhibitors such as clavulanate or tazobactam. To investigate the compatibility of the two phenotypes we used site-directed mutagenesis of the bla TEM-1gene to introduce into the TEM-1 β-lactamase amino acid substitutions that confer the ESBL phenotype: TEM-12 (Arg164→Ser), TEM-26 (Arg164→Ser plus Glu104→Lys), TEM-19 (Gly238→Ser), and TEM-15 (Gly238→Ser plus Glu104→Lys). These were combined with three sets of substitutions that confer inhibitor resistance: TEM-31 (Arg244→Cys), TEM-33 (Met69→Leu), and TEM-35 (Met69→Leu and Asn276→Asp). Introduction of the Arg244→Cys substitution gave rise to inhibitor-resistant hybrid enzymes that either lost ESBL activity (TEM-12, TEM-15, and TEM-19) or had reduced activity (TEM-26) against ceftazidime. In contrast, the introduction of Met69→Leu or Met69→Leu plus Asn276→Asp substitutions did not significantly affect the abilities of the enzymes to confer resistance to ceftazidime, although increased susceptibility to cefotaxime was observed with Escherichia coli strains that expressed the TEM-19 and TEM-26 β-lactamases. With the exception of the TEM-12 β-lactamase, introduction of the Met69→Leu substitution did not give rise to enzymes with increased resistance to clavulanate compared to that of the TEM-1 β-lactamase. However, introduction of the double substitution Met69→Leu plus Asn276→Asp in the ESBLs did give rise to low-level (TEM-19, TEM-15, and TEM-26) or moderate-level (TEM-12) clavulanate resistance. None of the hybrid enzymes were as resistant to clavulanate as the corresponding inhibitor-resistant TEM β-lactamase mutant, suggesting that active-site configuration in the ESBLs limits the degree of clavulanate resistance conferred.

scholarly journals Characterization of H9N2 influenza A viruses isolated from chicken products imported into Japan from China

2006 ◽  
Vol 135 (3) ◽  
pp. 386-391 ◽  
Author(s):  
M. MASE ◽  
M. ETO ◽  
K. IMAI ◽  
K. TSUKAMOTO ◽  
S. YAMAGUCHI
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Influenza A ◽  
H9n2 Virus ◽  
Amino Acid Substitutions ◽  
Influenza A Viruses ◽  
Potential Sources

We characterized eleven H9N2 influenza A viruses isolated from chicken products imported from China. Genetically they were classified into six distinct genotypes, including five already known genotypes and one novel genotype. This suggested that such multiple genotypes of the H9N2 virus have possibly already become widespread and endemic in China. Two isolates have amino-acid substitutions that confer resistance to amantadine in the M2 region, and this supported the evidence that this mutation might be a result of the wide application of amantadine for avian influenza treatment in China. These findings emphasize the importance of surveillance for avian influenza virus in this region, and of quarantining imported chicken products as potential sources for the introduction of influenza virus.

scholarly journals Molecular characterization of a 13-amino acid deletion in VP1 (1D) protein and novel amino acid substitutions in 3D polymerase protein of foot and mouth disease virus subtype A/Iran87

2011 ◽  
Vol 12 (4) ◽  
pp. 363 ◽  
Author(s):  
Majid Esmaelizad ◽  
Saber Jelokhani-Niaraki ◽  
Khadije Hashemnejad ◽  
Morteza Kamalzadeh ◽  
Mohsen Lotfi
Keyword(s):  
Amino Acid ◽  
Molecular Characterization ◽  
Disease Virus ◽  
Foot And Mouth Disease ◽  
Amino Acid Substitutions ◽  
Amino Acid Deletion ◽  
Mouth Disease Virus ◽  
Subtype A ◽  
Virus Subtype

scholarly journals Kinetic Properties and Metal Content of the Metallo-β-lactamase CcrA Harboring Selective Amino Acid Substitutions

1999 ◽  
Vol 274 (22) ◽  
pp. 15706-15711 ◽  
Author(s):  
Youjun Yang ◽  
David Keeney ◽  
Xue-jun Tang ◽  
Norman Canfield ◽  
Beth A. Rasmussen
Keyword(s):  
Amino Acid ◽  
Metal Content ◽  
Kinetic Properties ◽  
Amino Acid Substitutions

scholarly journals Characterization of amino acid substitutions in feline coronavirus 3C-like protease from a cat with feline infectious peritonitis treated with a protease inhibitor

2019 ◽  
Vol 237 ◽  
pp. 108398 ◽  
Author(s):  
Krishani Dinali Perera ◽  
Athri D. Rathnayake ◽  
Hongwei Liu ◽  
Niels C. Pedersen ◽  
William C. Groutas ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protease Inhibitor ◽  
Amino Acid Substitutions ◽  
Feline Infectious Peritonitis ◽  
Feline Coronavirus

scholarly journals Characterization of Amino Acid Substitutions in the Putative Binding Site of Bupropion in Glic

2020 ◽  
Vol 118 (3) ◽  
pp. 583a
Author(s):  
Dubem Onyejegbu ◽  
Jessica Shepherd ◽  
Elham Pirayesh ◽  
Akash Pandhare ◽  
Zackary R. Gallardo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Amino Acid Substitutions ◽  
Putative Binding Site

scholarly journals PER-6, an Extended-Spectrum β-Lactamase from Aeromonas allosaccharophila

2010 ◽  
Vol 54 (4) ◽  
pp. 1619-1622 ◽  
Author(s):  
Delphine Girlich ◽  
Laurent Poirel ◽  
Patrice Nordmann
Keyword(s):  
Amino Acid ◽  
Amino Acid Identity ◽  
Environmental Isolate ◽  
Kinetic Properties ◽  
Seine River ◽  
Acid Identity ◽  
Extended Spectrum

ABSTRACT An Aeromonas allosaccharophila environmental isolate recovered from the Seine River (Paris, France) produced a novel extended-spectrum β-lactamase, PER-6, that shared 92% amino acid identity with the closest ß-lactamase, PER-2. The kinetic properties of PER-6 showed a slightly increased affinity for carbapenems. The bla PER-6 gene was chromosomally located and bracketed by non-transposon-related structures.

Sign in / Sign up

Export Citation Format

Share Document