Academic literature on the topic 'Lactamase gene'
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Journal articles on the topic "Lactamase gene"
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Matsumoto, Yoshimi, and Matsuhisa Inoue. "Characterization of SFO-1, a Plasmid-Mediated Inducible Class A β-Lactamase from Enterobacter cloacae." Antimicrobial Agents and Chemotherapy 43, no. 2 (February 1, 1999): 307–13. http://dx.doi.org/10.1128/aac.43.2.307.
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ABSTRACT Enterobacter cloacae 8009 produced an inducible class A β-lactamase which hydrolyzed cefotaxime efficiently. It also hydrolyzed other β-lactams except cephamycins and carbapenems. The activity was inhibited by clavulanic acid and imipenem. Thebla gene was transferable to Escherichia coliby electroporation of plasmid DNA. The molecular mass of the β-lactamase was 29 kDa and its pI was 7.3. All of these phenotypic characteristics of the enzyme except for inducible production resemble those of some extended-spectrum class A β-lactamases like FEC-1. The gene encoding this β-lactamase was cloned and sequenced. The deduced amino acid sequence of the β-lactamase was homologous to the AmpA sequences of the Serratia fonticola chromosomal enzyme (96%), MEN-1 (78%), Klebsiella oxytoca chromosomal enzymes (77%), TOHO-1 (75%), and FEC-1 (72%). The conserved sequences of class A β-lactamases, including the S-X(T)-X(S)-K motif, in the active site were all conserved in this enzyme. On the basis of the high degree of homology to the β-lactamase of S. fonticola, the enzyme was named SFO-1. The ampR gene was located upstream of the ampA gene, and the AmpR sequence of SFO-1 had homology with the AmpR sequences of the chromosomal β-lactamases from Citrobacter diversus(80%), Proteus vulgaris (68%), and Pseudomonas aeruginosa (60%). SFO-1 was also inducible in E. coli. However, a transformant harboring plasmid without intactampR produced a small amount of β-lactamase constitutively, suggesting that AmpR works as an activator ofampA of SFO-1. This is the first report from Japan describing an inducible plasmid-mediated class A β-lactamase in gram-negative bacteria.
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Pradel, N., J. Delmas, L. F. Wu, C. L. Santini, and R. Bonnet. "Sec- and Tat-Dependent Translocation of β-Lactamases across the Escherichia coli Inner Membrane." Antimicrobial Agents and Chemotherapy 53, no. 1 (November 3, 2008): 242–48. http://dx.doi.org/10.1128/aac.00642-08.
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ABSTRACT β-Lactamases represent the major resistance mechanism of gram-negative bacteria against β-lactam antibiotics. The amino acid sequences of these proteins vary widely, but all are located in the periplasm of bacteria. In this study, we investigated the translocation mechanism of representative β-lactamases in an Escherichia coli model. N-terminal signal sequence analyses, antibiotic activity assay, and direct measurement of translocation of a green fluorescent protein (GFP) reporter fused to β-lactamases revealed that most were exported via the Sec pathway. However, the Stenotrophomonas maltophilia L2 β-lactamase was exported via the E. coli Tat translocase, while the S. maltophilia L1 β-lactamase was Sec dependent. These results show the possible Tat-dependent translocation of β-lactamases in the E. coli model system. In addition, the mutation of the cytoskeleton-encoding gene mreB, which may be involved in the spatial organization of penicillin-binding proteins, decreased the MIC of β-lactams for β-lactamase-producing E. coli. These findings provide new knowledge about β-lactamase translocation, a putative new target for addressing β-lactamase-mediated resistance.
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Lau, Susanna K. P., Pak-leung Ho, Maria W. S. Li, Hoi-wah Tsoi, Raymond W. H. Yung, Patrick C. Y. Woo, and Kwok-yung Yuen. "Cloning and Characterization of a Chromosomal Class C β-Lactamase and Its Regulatory Gene in Laribacter hongkongensis." Antimicrobial Agents and Chemotherapy 49, no. 5 (May 2005): 1957–64. http://dx.doi.org/10.1128/aac.49.5.1957-1964.2005.
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ABSTRACT Laribacter hongkongensis, a newly discovered bacterium recently shown to be associated with community-acquired gastroenteritis, is generally resistant to most β-lactams except the carbapenems. We describe the cloning and characterization of a novel chromosomal class C β-lactamase and its regulatory gene in L. hongkongensis. Two genes, ampC and ampR, were cloned by inserting restriction fragments of genomic DNA from L. hongkongensis strain HLHK5 into pBK-CMV to give the recombinant plasmid pBK-LHK-5. The ampR and ampC genes and their promoters were divergently oriented, with the ampR gene immediately upstream of the ampC gene and an intercistronic Lys-R motif, typical of inducible ampC-ampR regulatory systems. The deduced amino acid sequence of the cloned AmpC β-lactamase (pI 8.1) contained consensus motifs characteristic of class C β-lactamases but had identities no greater than 46% to known class C β-lactamases. The kinetic properties of this AmpC were also compatible with those of a class C β-lactamase. PCR of 20 clinical isolates of L. hongkongensis, including HLHK5, showed the presence of both ampC and ampR genes in all isolates. Southern hybridization suggested that the ampC gene of HLHK5 was chromosomally encoded. Subcloning experiments showed that the expression of the ampC gene of HLHK5 was regulated by its ampR gene, which acts as a repressor. The β-lactamase characterized from strain HLHK5 was named LHK-5 (gene, bla LHK-5) and represents the first example of AmpC β-lactamase in the β subdivision of proteobacteria.
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Fournier, B., and P. H. Roy. "Variability of chromosomally encoded beta-lactamases from Klebsiella oxytoca." Antimicrobial Agents and Chemotherapy 41, no. 8 (August 1997): 1641–48. http://dx.doi.org/10.1128/aac.41.8.1641.
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The beta-lactamase genes of Klebsiella oxytoca were previously divided into two main groups: bla(OXY-1) and bla(OXY-2). The two beta-lactamase groups were each represented by beta-lactamases with four different pIs. In each group, one form of beta-lactamase is more frequent than the others combined. The beta-lactamase gene of each representative beta-lactamase with a different pI that was not yet sequenced (pIs 5.7, 6.8 [OXY-2], 7.1, 8.2, and 8.8 [OXY-1]) was cloned and sequenced. The susceptibility patterns as well as relative rates and kinetic parameters for beta-lactam hydrolysis revealed that OXY-2 enzymes hydrolyzed several of the beta-lactams that were examined (carbenicillin, cephalothin, cefamandole, ceftriaxone, and aztreonam) at a greater rate than the OXY-1 enzymes did. Comparison of K. oxytoca beta-lactamases with plasmid-mediated extended-spectrum beta-lactamases MEN-1 and TOHO-1 implied that the threonine at position 168 present in OXY-2 beta-lactamase instead of the alanine in OXY-1 could be responsible for its modified substrate hydrolysis. In each group, the beta-lactamase with a variant pI differs from the main form of beta-lactamase by one to five amino acid substitutions. The substrate profile and the 50% inhibitory concentrations revealed that all substitutions differing from the main form of beta-lactamase were neutral except one difference in the OXY-1 group. This substitution of an Ala to a Gly at position 237 increases the hydrolysis of some beta-lactams, particularly aztreonam; decreases the hydrolysis of benzylpenicillin, cephaloridine, and cefamandole, and decreases the susceptibility to clavulanic acid (fivefold increase in the 50% inhibitory concentration).
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Ma, Ling, Yoshikazu Ishii, Masaji Ishiguro, Hiroshi Matsuzawa, and Keizo Yamaguchi. "Cloning and Sequencing of the Gene Encoding Toho-2, a Class A β-Lactamase Preferentially Inhibited by Tazobactam." Antimicrobial Agents and Chemotherapy 42, no. 5 (May 1, 1998): 1181–86. http://dx.doi.org/10.1128/aac.42.5.1181.
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ABSTRACT Escherichia coli TUM1083, which is resistant to ampicillin, carbenicillin, cephaloridine, cephalothin, piperacillin, cefuzonam, and aztreonam while being sensitive to cefoxitin, moxalactam, cefmetazole, ceftazidime, and imipenem, was isolated from the urine of a patient treated with β-lactam antibiotics. The β-lactamase (Toho-2) purified from the bacteria hydrolyzed β-lactam antibiotics such as penicillin G, carbenicillin, cephaloridine, cefoxitin, cefotaxime, ceftazidime, and aztreonam and especially had increased relative hydrolysis rates for cephalothin, cephaloridine, cefotaxime, and ceftizoxime. Different from other extended-spectrum β-lactamases, Toho-2 was inhibited 16-fold better by the β-lactamase inhibitor tazobactam than by clavulanic acid. Resistance to β-lactams was transferred by conjugation from E. coliTUM1083 to E. coli ML4909, and the transferred plasmid was about 54.4 kbp, belonging to the incompatibility group IncFII. The cefotaxime resistance gene for Toho-2 was subcloned from the 54.4-kbp plasmid. The sequence of the gene was determined, and the open reading frame of the gene was found to consist of 981 bases. The nucleotide sequence of the gene (DDBJ accession no. D89862) designated asbla toho was found to have 76.3% identity to class A β-lactamase CTX-M-2 and 76.2% identity to Toho-1. It has 55.9% identity to SHV-1 β-lactamase and 47.5% identity to TEM-1 β-lactamase. Therefore, the newly isolated β-lactamase designated as Toho-2 produced by E. coli TUM1083 is categorized as an enzyme similar to Toho-1 group β-lactamases rather than to mutants of TEM or SHV enzymes. According to the amino acid sequence deduced from the DNA sequence, the precursor consisted of 327 amino acid residues. Comparison of Toho-2 with other β-lactamase (non-Toho-1 group) suggests that the substitutions of threonine for Arg-244 and arginine for Asn-276 are important for the extension of the substrate specificity.
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Gazouli, Maria, Eva Tzelepi, Sergei V. Sidorenko, and Leonidas S. Tzouvelekis. "Sequence of the Gene Encoding a Plasmid-Mediated Cefotaxime-Hydrolyzing Class A β-Lactamase (CTX-M-4): Involvement of Serine 237 in Cephalosporin Hydrolysis." Antimicrobial Agents and Chemotherapy 42, no. 5 (May 1, 1998): 1259–62. http://dx.doi.org/10.1128/aac.42.5.1259.
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ABSTRACT The sequence of the gene encoding a novel cefotaxime-hydrolyzing β-lactamase (CTX-M-4) was determined. It was located in a plasmid harbored by a Salmonella typhimurium strain. CTX-M-4 was similar to the plasmidic cefotaxime-hydrolyzing β-lactamases CTX-M-2 and Toho-1 and related to the chromosomal β-lactamase ofKlebsiella oxytoca. A Ser-237→Ala substitution, introduced by site-directed mutagenesis, caused minor alterations in the interaction of CTX-M-4 with β-lactams, reducing slightly the relative hydrolytic activity against cefotaxime and the susceptibility to inhibition by clavulanate.
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Queenan, Anne Marie, Stephen Jenkins, and Karen Bush. "Cloning and Biochemical Characterization of FOX-5, an AmpC-Type Plasmid-Encoded β-Lactamase from a New York CityKlebsiella pneumoniae Clinical Isolate." Antimicrobial Agents and Chemotherapy 45, no. 11 (November 1, 2001): 3189–94. http://dx.doi.org/10.1128/aac.45.11.3189-3194.2001.
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ABSTRACT Klebsiella pneumoniae 5064, isolated in New York, carried plasmid-mediated resistance to multiple β-lactams and was unresponsive to clavulanic acid. The β-lactamase gene responsible for cephalosporin resistance encoded FOX-5, with 96 to 97% amino acid identities to other members of the FOX family of β-lactamases. Thebla FOX-5 coding region was located next to a transposase gene from the Aeromonas salmonicidainsertion element ISAS2.
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Walsh, Timothy R., Mark A. Toleman, Laurent Poirel, and Patrice Nordmann. "Metallo-β-Lactamases: the Quiet before the Storm?" Clinical Microbiology Reviews 18, no. 2 (April 2005): 306–25. http://dx.doi.org/10.1128/cmr.18.2.306-325.2005.
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SUMMARY The ascendancy of metallo-β-lactamases within the clinical sector, while not ubiquitous, has nonetheless been dramatic; some reports indicate that nearly 30% of imipenem-resistant Pseudomonas aeruginosa strains possess a metallo-β-lactamase. Acquisition of a metallo-β-lactamase gene will invariably mediate broad-spectrum β-lactam resistance in P. aeruginosa, but the level of in vitro resistance in Acinetobacter spp. and Enterobacteriaceae is less dependable. Their clinical significance is further embellished by their ability to hydrolyze all β-lactams and by the fact that there is currently no clinical inhibitor, nor is there likely to be for the foreseeable future. The genes encoding metallo-β-lactamases are often procured by class 1 (sometimes class 3) integrons, which, in turn, are embedded in transposons, resulting in a highly transmissible genetic apparatus. Moreover, other gene cassettes within the integrons often confer resistance to aminoglycosides, precluding their use as an alternative treatment. Thus far, the metallo-β-lactamases encoded on transferable genes include IMP, VIM, SPM, and GIM and have been reported from 28 countries. Their rapid dissemination is worrisome and necessitates the implementation of not just surveillance studies but also metallo-β-lactamase inhibitor studies securing the longevity of important anti-infectives.
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Madinier, I., T. Fosse, J. Giudicelli, and R. Labia. "Cloning and Biochemical Characterization of a Class A β-Lactamase from Prevotella intermedia." Antimicrobial Agents and Chemotherapy 45, no. 8 (August 1, 2001): 2386–89. http://dx.doi.org/10.1128/aac.45.8.2386-2389.2001.
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ABSTRACT The gene encoding a β-lactamase of Prevotella intermedia was cloned and sequenced. This gene, calledcfxA2, shared 98% identity with cfxA, the structural gene of a β-lactamase previously described inBacteroides vulgatus. The deduced protein sequence had a K272E substitution. CfxA2 had the characteristics of class A, group 2e β-lactamases.
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Moubareck, Carole, Sylvie Brémont, Marie-Christine Conroy, Patrice Courvalin, and Thierry Lambert. "GES-11, a Novel Integron-Associated GES Variant in Acinetobacter baumannii." Antimicrobial Agents and Chemotherapy 53, no. 8 (May 18, 2009): 3579–81. http://dx.doi.org/10.1128/aac.00072-09.
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ABSTRACT New extended-spectrum β-lactamase GES-11 was detected in Acinetobacter baumannii BM4674. The enzyme conferred resistance to β-lactams, including aztreonam, and reduced susceptibility to carbapenems. The structural gene was part of a class 1 integron borne by self-transferable plasmid pIP847. GES-type β-lactamases have not been reported previously in A. baumannii.
Dissertations / Theses on the topic "Lactamase gene"
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Alfredson, David, and n/a. "Characterisation of the B-Lactamase Gene From Campylobacter Jejuni." Griffith University. Institute for Glycomics, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060111.172351.
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Thermophilic Campylobacter species such as Campylobacter jejuni and Campylobacter coli are recognised worldwide as major causes of acute gastroenteritis in humans. Campylobacteriosis is frequently a mild to moderate self-limited illness and most cases do not require antimicrobial therapy; antimicrobial therapy is necessary for patients with systemic Campylobacter infections, for patients with severe disease, or for immunosuppressed patients. Antimicrobial susceptibility testing of Campylobacter species using disk diffusion currently is not standardised by the National Committee for Clinical Laboratory Standards (NCCLS), however, in order to monitor the prevalence of antimicrobial resistance in Campylobacter species, there is a need for standardised or calibrated methods of susceptibility testing. Initially, 90 human clinical isolates of thermophilic Campylobacter species from Southeast Queensland, Australia, were screened for resistance to ampicillin, erythromycin and tetracycline using the disk diffusion susceptibility testing method. Levels of resistance were then determined using E test MIC and agar dilution methods to determine the reliability of disk diffusion results. Results of the disk diffusion testing showed 87 (97%) isolates resistant to ampicillin, 14 (16%) isolates were resistant to tetracycline and three (3.4%) isolates were resistant to erythromycin. Results of disk diffusion testing showed 100% correlation (+1 log2 dilution) with agar dilution for erythromycin and tetracycline, and 77% for ampicillin. E test showed 68% correlation with agar dilution for ampicillin, 100% for erythromycin and 64% for tetracycline. These data suggest that disk diffusion susceptibility testing may be used to screen thermophilic Campylobacter spp. for putative resistance to erythromycin and tetracycline and that the incidence of resistance of Campylobacter spp. to erythromycin and tetracycline is low in Southeast Queensland, Australia. Agar dilution remains the most accurate method for determination of ampicillin susceptibility. Numerical analyses of restriction endonuclease (RE) fragment profiles were performed to elucidate relatedness of the antibiotic resistant isolates and the results suggested a high level of isolate variation. The role of the B-lactamase in the resistance of C. jejuni to various B-lactams has been well documented and B-lactamase production in C. jejuni has been reported in 83-93% of strains. The expression and characterisation of the Campylobacter B-lactamase, however, has not been described. In this work, standard cloning techniques utilising a high-copy number E. coli cloning vector and a previously described E. coli-Campylobacter shuttle cloning vector were unsuccessful in isolation and expression of the C. jejuni B-lactamase gene in E. coli, possibly due to a lack of expression of the campylobacter gene in its host or low efficiency of transformation. Therefore, in order to facilitate the isolation, expression and characterisation of the C. jejuni B-lactamase gene, it was necessary to construct a new E.coli-Campylobacter shuttle cloning vector for the purposes of expressing the C. jejuni B-lactamase in Campylobacter. To aid in the construction of the vector, the sequence and genetic organisation of a 4.0-kb cryptic plasmid, termed pCJ419, identified in a human clinical isolate of C. jejuni was determined. Plasmid pCJ419 is a circular molecule of 4013 bp and contains four open reading frames (ORFs), the products of which share significant sequence similarity with putative proteins from known C. jejuni and C. coli plasmids. ORF-1 encodes a putative mobilisation protein (Mob); ORF-2 and ORF-3 encode proteins which have high identity to putative RepA and RepB proteins, respectively, of known C. jejuni and C. coli plasmids. ORF-4 encodes a protein which has high identity to a hypothetical protein of unknown function, Cjp32, previously described in a pVir plasmid of C. jejuni. Tandem repeating sequences typical of a plasmid replication origin (ori) were identified upstream of the DNA sequences encoding putative replication initiation proteins RepA and RepB. An E. coli-Campylobacter shuttle cloning vector, pGU0202, was constructed using plasmid pMW2 which harbours a Campylobacter-derived kanamycin-resistance gene, aphA(3)-III. The sequences encoding pCJ419 mob, repA and repB were inserted upstream of aphA(3)-III resulting in a stable construct of 6174 bp that was used successfully to transform both E. coli and Campylobacter. Subsequently, a novel molecular class D ?-lactamase gene, blaOXA-61, from a B-lactamase-positive, ampicillin-resistant (MIC 64 mg l-1), clinical strain of Campylobacter jejuni, strain GC015 was isolated, cloned and characterized using the newly constructed shuttle vector pGU0202. An open reading frame of 774 bp was identified on a ClaI genomic fragment of 2.2 kb and encodes a protein of 257 amino acids. Conserved motifs composed of identical amino acids typical of penicillin-recognising proteins and specific class D motifs were identified. blaOXA-61 was cloned into the shuttle cloning vector pGU0202 and expressed in B-lactamase-negative, ampicillin-susceptible C. jejuni and E. coli. A conserved 122-bp sequence directly upstream of blaOXA-61 was identified and shown to be required in cis for high-level resistance of Campylobacter to the penicillins although blaOXA-61 expressed only at low levels in E.coli. Southern hybridisation analysis demonstrated that the bla gene was chromosomally encoded and present on the same BglII and ClaI-digested genomic DNA fragments from various strains of Campylobacter with ampicillin MICs of between 4 and 64 mg l-1. In addition, DNA fragments encoding two putative zinc-dependent hydrolases from the metallo-B-lactamase superfamily, designated GLX2-1 and GLX2-2, were identified in a clinical isolate of Campylobacter jejuni, strain 012, cloned and sequenced. A strictly conserved motif, -H-X-H-X-D-, characteristic of the metallo- B-lactamase superfamily of proteins, including the class B metallo- B-lactamases, was identified in both proteins although functional B-lactamase could not be expressed in either E. coli or C. coli transformed using the C. jejuni hydrolase-containing shuttle vector pGU0202. Further work is warranted to determine the exact function of these proteins.
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Alfredson, David. "Characterisation of the B-Lactamase Gene From Campylobacter Jejuni." Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367271.
Full textAbstract:
Thermophilic Campylobacter species such as Campylobacter jejuni and Campylobacter coli are recognised worldwide as major causes of acute gastroenteritis in humans. Campylobacteriosis is frequently a mild to moderate self-limited illness and most cases do not require antimicrobial therapy; antimicrobial therapy is necessary for patients with systemic Campylobacter infections, for patients with severe disease, or for immunosuppressed patients. Antimicrobial susceptibility testing of Campylobacter species using disk diffusion currently is not standardised by the National Committee for Clinical Laboratory Standards (NCCLS), however, in order to monitor the prevalence of antimicrobial resistance in Campylobacter species, there is a need for standardised or calibrated methods of susceptibility testing. Initially, 90 human clinical isolates of thermophilic Campylobacter species from Southeast Queensland, Australia, were screened for resistance to ampicillin, erythromycin and tetracycline using the disk diffusion susceptibility testing method. Levels of resistance were then determined using E test MIC and agar dilution methods to determine the reliability of disk diffusion results. Results of the disk diffusion testing showed 87 (97%) isolates resistant to ampicillin, 14 (16%) isolates were resistant to tetracycline and three (3.4%) isolates were resistant to erythromycin. Results of disk diffusion testing showed 100% correlation (+1 log2 dilution) with agar dilution for erythromycin and tetracycline, and 77% for ampicillin. E test showed 68% correlation with agar dilution for ampicillin, 100% for erythromycin and 64% for tetracycline. These data suggest that disk diffusion susceptibility testing may be used to screen thermophilic Campylobacter spp. for putative resistance to erythromycin and tetracycline and that the incidence of resistance of Campylobacter spp. to erythromycin and tetracycline is low in Southeast Queensland, Australia. Agar dilution remains the most accurate method for determination of ampicillin susceptibility. Numerical analyses of restriction endonuclease (RE) fragment profiles were performed to elucidate relatedness of the antibiotic resistant isolates and the results suggested a high level of isolate variation. The role of the B-lactamase in the resistance of C. jejuni to various B-lactams has been well documented and B-lactamase production in C. jejuni has been reported in 83-93% of strains. The expression and characterisation of the Campylobacter B-lactamase, however, has not been described. In this work, standard cloning techniques utilising a high-copy number E. coli cloning vector and a previously described E. coli-Campylobacter shuttle cloning vector were unsuccessful in isolation and expression of the C. jejuni B-lactamase gene in E. coli, possibly due to a lack of expression of the campylobacter gene in its host or low efficiency of transformation. Therefore, in order to facilitate the isolation, expression and characterisation of the C. jejuni B-lactamase gene, it was necessary to construct a new E.coli-Campylobacter shuttle cloning vector for the purposes of expressing the C. jejuni B-lactamase in Campylobacter. To aid in the construction of the vector, the sequence and genetic organisation of a 4.0-kb cryptic plasmid, termed pCJ419, identified in a human clinical isolate of C. jejuni was determined. Plasmid pCJ419 is a circular molecule of 4013 bp and contains four open reading frames (ORFs), the products of which share significant sequence similarity with putative proteins from known C. jejuni and C. coli plasmids. ORF-1 encodes a putative mobilisation protein (Mob); ORF-2 and ORF-3 encode proteins which have high identity to putative RepA and RepB proteins, respectively, of known C. jejuni and C. coli plasmids. ORF-4 encodes a protein which has high identity to a hypothetical protein of unknown function, Cjp32, previously described in a pVir plasmid of C. jejuni. Tandem repeating sequences typical of a plasmid replication origin (ori) were identified upstream of the DNA sequences encoding putative replication initiation proteins RepA and RepB. An E. coli-Campylobacter shuttle cloning vector, pGU0202, was constructed using plasmid pMW2 which harbours a Campylobacter-derived kanamycin-resistance gene, aphA(3’)-III. The sequences encoding pCJ419 mob, repA and repB were inserted upstream of aphA(3’)-III resulting in a stable construct of 6174 bp that was used successfully to transform both E. coli and Campylobacter. Subsequently, a novel molecular class D ?-lactamase gene, blaOXA-61, from a B-lactamase-positive, ampicillin-resistant (MIC 64 mg l-1), clinical strain of Campylobacter jejuni, strain GC015 was isolated, cloned and characterized using the newly constructed shuttle vector pGU0202. An open reading frame of 774 bp was identified on a ClaI genomic fragment of 2.2 kb and encodes a protein of 257 amino acids. Conserved motifs composed of identical amino acids typical of penicillin-recognising proteins and specific class D motifs were identified. blaOXA-61 was cloned into the shuttle cloning vector pGU0202 and expressed in B-lactamase-negative, ampicillin-susceptible C. jejuni and E. coli. A conserved 122-bp sequence directly upstream of blaOXA-61 was identified and shown to be required in cis for high-level resistance of Campylobacter to the penicillins although blaOXA-61 expressed only at low levels in E.coli. Southern hybridisation analysis demonstrated that the bla gene was chromosomally encoded and present on the same BglII and ClaI-digested genomic DNA fragments from various strains of Campylobacter with ampicillin MICs of between 4 and 64 mg l-1. In addition, DNA fragments encoding two putative zinc-dependent hydrolases from the metallo-B-lactamase superfamily, designated GLX2-1 and GLX2-2, were identified in a clinical isolate of Campylobacter jejuni, strain 012, cloned and sequenced. A strictly conserved motif, -H-X-H-X-D-, characteristic of the metallo- B-lactamase superfamily of proteins, including the class B metallo- B-lactamases, was identified in both proteins although functional B-lactamase could not be expressed in either E. coli or C. coli transformed using the C. jejuni hydrolase-containing shuttle vector pGU0202. Further work is warranted to determine the exact function of these proteins.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Institute for Glycomics
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Mossakowska, Danuta Ewa Irena. "Molecular characterisation of the OXA-2 beta-lactamase." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/847832/.
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The DNA sequence of the gene coding for the OXA-2 beta-lactamase has been completed. The primary amino acid sequence deduced from the DNA sequence was used to study homologies with other beta-lactamases; no good homologies were observed with any class of beta-lactamase. A more detailed analysis has revealed from comparison of both primary and predicted secondary structure, that the OXA-2 beta-lactamase may be more closely related to class A enzymes. Confirmation that the OXA-2 beta-lactamase is a serine enzyme has come from the DNA sequence and the interaction with mechanism based inactivators. Clavulanic acid and a novel beta-lactamase inhibitor, BRL36148, both interact specifically with the OXA-2 beta-lactamase by branched pathway mechanisms. Analysis of inactivated enzymes by peptide mapping and isoelcetric focusing have revealed that more than one inactive enzyme species is formed with each inactivator. A specific DNA probe was designed to come entirely from within the coding sequence of the OXA-2 beta-lactamase gene. This probe was found to interact only with plasmids specifying the OXA-2 or OXA-3 type enzymes. These results confirm earlier observations that OXA-2 and OXA-3 beta-lactamases are related. Another probe which comprised the whole of the OXA-2 beta-lactamase gene as well as segments of DNA on either side of the gene, was found to hybridise with a number of resistance plasmids. This interaction suggests that multi resistance plasmids carry common segments of DNA. Characterisation of the physical properties of the OXA-2 enzyme by analytical ultracentrifugation have not only confirmed the dimeric nature of this beta-lactamase but have also shown that this enzyme forms aggregates at high protein concentrations. Probing of the enzyme structure with trypsin, strongly points to the OXA-2 beta-lactamase having a domain structure.
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Ali, Norryai A. "Expression and secretion of OXA-2 beta-lactamase by Streptomyces lividans." Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/847196/.
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The OXA-2 beta-lactamase gene was first found on a conjugative plasmid R46 from a clinical isolate of Salmonella typhimurium. To test the expression and secretion of OXA-2 beta-lactamase in Streptomyces lividans a shuttle plasmid (pSU101) was created by fusing an Escherichia coli plasmid (pSU8) carrying the OXA-2 beta-lactamase gene with the S. lividans vector pLJ61. The OXA-2 beta-lactamase gene specified by the hybrid plasmid PSU101 was expressed in S. lividans, although at a lower level than in coli. Almost all the beta-lactamase activity was found in the culture supernatant of S. lividans, whereas in E. coli the enzyme was almost wholly cell associated. The identity of the enzyme was established by substrate specificity and isoelectric focusing. The stability and integrity of the plasmid pSU101 in both E. coli and lividans was determined, in comparison with that of pSU8 and pLJ61 plasmids. The promoter regions of the OXA-2 beta-lactamase gene were identified by using promoter-probe plasmid vectors; and by S1 mapping of the transcriptional start-sites coupled to the DNA sequencing of the OXA-2 beta-lactamase gene. Multiple transcriptional start sites were found in both hosts, with the origin of transcription apparently different in the two organisms. Part of this work has been published as a scientific paper which is appended.
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Doyle, Jamielynn. "Identification of an L2 ß-lactamase gene from Stenotrophomonas maltophilia OR02." Youngstown State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1528369969169163.
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Cooper, Kerri W. "Expression, degradation, and applications of Escherichia coli TolA-beta-lactamase fusion proteins /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/9815.
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Albaaj, Mohammed. "Diversity of β-Lactamase Genes in Gram-Negative Soil Bacteria from Northwest Ohio." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1566553116919146.
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Henderson, Ian. "Solving the inclusion body problem - a case study : high level expression of TEM-1 #beta#-lactamase in Escherichia coli." Thesis, University of Warwick, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282432.
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Li, Wai-shan. "Cloning and characterization of chromosomal class C [beta]-Lactamase and its regulatory gene in Laribacter hongkongensis." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31046393.
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Li, Wai-shan, and 李慧珊. "Cloning and characterization of chromosomal class C {221}-Lactamase and its regulatory gene in Laribacter hongkongensis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31046393.
Full textBooks on the topic "Lactamase gene"
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Rosa, Abel De La. Deletion analysis of the promoter/operator nucleotide sequence of the metF gene from Escherichia Coli K-12: The use of Beta-lactamase as a reporter gene. 1991.
Find full textBook chapters on the topic "Lactamase gene"
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Khuc, Thai, Chia-Wen Hsu, Srilatha Sakamuru, and Menghang Xia. "Using β-Lactamase and NanoLuc Luciferase Reporter Gene Assays to Identify Inhibitors of the HIF-1 Signaling Pathway." In Methods in Molecular Biology, 23–31. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-6346-1_3.
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Ogawara, Hiroshi. "Beta-Lactamase Genes from Streptomyces Species." In Genetics and Product Formation in Streptomyces, 195–202. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-5922-7_22.
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Carter, Ian. "Metallo β Lactamases Gene blaimp, blaspm and blavim Detection by Multiplex Real-Time TaqMan Assay on the Smartcycler." In PCR for Clinical Microbiology, 423–27. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9039-3_74.
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TOWNER, KEVIN J. "Detection of TEM β-Lactamase Genes Using DNA Probes." In Gene Probes for Bacteria, 459–83. Elsevier, 1990. http://dx.doi.org/10.1016/b978-0-12-463000-0.50022-0.
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Palzkill, Timothy, Wanzhi Huang, and Joseph Petrosino. "Complete mutagenesis of the gene encoding TEM-1 β-lactamase." In Techniques in Protein Chemistry, 827–36. Elsevier, 1997. http://dx.doi.org/10.1016/s1080-8914(97)80080-4.
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Dembélé, René, Wendpoulomdé A.D. Kaboré, Issiaka Soulama, Oumar Traoré, Nafissatou Ouédraogo, Ali Konaté, Nathalie K. Guessennd, et al. "Beta-Lactamase-Producing Genes and Integrons in Escherichia coli from Diarrheal Children in Ouagadougou, Burkina Faso." In Diarrhea - Novel Advances and Future Perspectives in the Etiological Diagnosis and Management [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103169.
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This study aimed to determine the resistance of diarrheagenic Escherichia coli (DEC) strains to β-lactams antibiotics and to perform the molecular characterization of extended-spectrum β-lactamases (ESBLs) and integrons genes. It was carried out from August 2013 to October 2015 and involved 31 DEC strains isolated from diarrheal stools samples collected from children less than 5 years. The identification and characterization of DEC strains were done through the standard biochemical tests that were confirmed using API 20E and polymerase chain reaction (PCR). The antibiogram was realized by the disk diffusion method, then an amplification of the β-lactamase resistance genes and integrons by PCR was done. Out of the 419 E. coli, 31 isolates (7.4%) harbored the DEC virulence genes. From these DEC, 21 (67.7%) were ESBL-producing E. coli. Susceptibility to ESBL-producing E. coli showed that the majority of isolates were highly resistant to amoxicillin (77.4%), amoxicillin-clavulanic acid (77.4%), and piperacillin (64.5%). The following antibiotic resistance genes and integron were identified: blaTEM (6.5%), blaSHV (19.4%), blaOXA (38.7%), blaCTX-M (9.7%), Int1 (58.1%), and Int3 (19.4%). No class 2 integron (Int2) was characterized. Because of the high prevalence of multidrug-resistant ESBL organisms found, there is a need of stringent pediatric infection control measures.
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Zlokarnik, Gregor. "[15] Fusions to β-lactamase as a reporter for gene expression in live mammalian cells." In Methods in Enzymology, 221–41. Elsevier, 2000. http://dx.doi.org/10.1016/s0076-6879(00)26057-6.
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"Molecular detection of DHA-1 AmpC beta-lactamase gene in Enterobacteriaceae clinical isolates in Indonesia." In Advances in Biomolecular Medicine, edited by B. Diela, S. Sudigdoadi, A. I. Cahyadi, B. A. P. Wilopo, I. M. W. Dewi, and C. B. Kartasasmita, 13–18. CRC Press, 2017. http://dx.doi.org/10.1201/9781315208619-4.
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Primrose, Sandy B. "Understanding Pathogen Populations: Klebsiella pneumoniae." In Microbiology of Infectious Disease, 47–52. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192863843.003.0006.
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Klebsiella pneumoniae is widespread in the environment and is a human commensal but only a small number of strains cause human infections. Human infections are of two types: hospital-acquired infections (HAI) and community-acquired infections (CAI). Klebsiella pneumoniae is resistant to ampicillin because it has a bla gene, but many clinical isolates are resistant to most β-lactam antibiotics because of mutations in the bla gene or by the acquisition of genes encoding other β-lactamases. Strains causing HAI are opportunistic pathogens but are difficult to treat because they are multi-drug resistant. Most of these strains circulate locally but a small number for unknown reasons have spread globally. Strains causing CAI are true pathogens and are hypervirulent but sensitive to most antibiotics. They are largely restricted to south-east Asia and Taiwan but the reason for this is not known.
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Ullah, Waheed, and Shandana Ali. "Antimicrobial Resistance in Escherichia coli." In Escherichia coli [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101583.
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The ability of microbes to resist or neutralize the action of drugs that have been used against microbes is considered as antimicrobial resistance (AMR). AMR among different strains of Escherichia coli is considered as a major threat to public health. Drug-resistant in E. coli is found predominantly in the hospital sittings, in the community, and surrounding environment. It has adopted different defensive strategies to minimize the effects of drugs. Extended-spectrum β-lactamase (ESBL), fluoroquinolones, and carbapenemases have been considered as strong resistance strategies being present in most of resistant bacterial strains. Mobile genetic elements (MGEs) have the major contribution in the transfer of resistance genes in between or among bacterial cells. Plasmids are normally present in most of resistant strains, helping in the transfer of genetic material between bacterial cells. Transposons another MGEs, are being considered as one of the major sources of resistance transmission. Collectively, MGEs play an important role in facilitating in exchange, acquisition, and dissemination of resistance genes. Resistance in E. coli has been reported worldwide and there is variation in its resistance pattern. CTX-M ESBLs, carbapenems, colistin-resistant, and ST-131 E. coli resistant clones are considered the most dominant phenotypes. The aforesaid resistant variants are predominantly found in densely populated regions, Sub-Saharan Africa, China, and South Asian countries.
Conference papers on the topic "Lactamase gene"
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Kromer-Edwards, Cory, Mariana Castanheira, and Suely Oliveira. "Year, Location, and Species Information In Predicting MIC Values with Beta-Lactamase Genes." In 2020 IEEE International Conference on Bioinformatics and Biomedicine (BIBM). IEEE, 2020. http://dx.doi.org/10.1109/bibm49941.2020.9313331.
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Wahab, Atqah Abdul, Emad Ibrahim, Ali A. Sultan, Jana Jass, and Mazen A. Sid Ahmed. "Variability of ß-lactamase resistance Pseudomonas aeruginosa genes infecting patients with cystic fibrosis." In ERS International Congress 2021 abstracts. European Respiratory Society, 2021. http://dx.doi.org/10.1183/13993003.congress-2021.pa2353.
Full textReports on the topic "Lactamase gene"
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Willis, C., F. Jorgensen, S. A. Cawthraw, H. Aird, S. Lai, M. Chattaway, I. Lock, E. Quill, and G. Raykova. A survey of Salmonella, Escherichia coli (E. coli) and antimicrobial resistance in frozen, part-cooked, breaded or battered poultry products on retail sale in the United Kingdom. Food Standards Agency, May 2022. http://dx.doi.org/10.46756/sci.fsa.xvu389.
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Frozen, breaded, ready-to-cook chicken products have been implicated in outbreaks of salmonellosis. Some of these outbreaks can be large. For example, one outbreak of Salmonella Enteritidis involved 193 people in nine countries between 2018 and 2020, of which 122 cases were in the UK. These ready-to-cook products have a browned, cooked external appearance, which may be perceived as ready-to-eat, leading to mishandling or undercooking by consumers. Continuing concerns about these products led FSA to initiate a short-term (four month), cross-sectional surveillance study undertaken in 2021 to determine the prevalence of Salmonella spp., Escherichia coli and antimicrobial resistance (AMR) in frozen, breaded or battered chicken products on retail sale in the UK. This study sought to obtain data on AMR levels in Salmonella and E. coli in these products, in line with a number of other FSA instigated studies of the incidence and nature of AMR in the UK food chain, for example, the systematic review (2016). Between the beginning of April and the end of July 2021, 310 samples of frozen, breaded or battered chicken products containing either raw or partly cooked chicken, were collected using representative sampling of retailers in England, Wales, Scotland and Northern Ireland based on market share data. Samples included domestically produced and imported chicken products and were tested for E. coli (including extended-spectrum beta-lactamase (ESBL)-producing, colistin-resistant and carbapenem-resistant E. coli) and Salmonella spp. One isolate of each bacterial type from each contaminated sample was randomly selected for additional AMR testing to determine the minimum inhibitory concentration (MIC) for a range of antimicrobials. More detailed analysis based on Whole Genome Sequencing (WGS) data was used to further characterise Salmonella spp. isolates and allow the identification of potential links with human isolates. Salmonella spp. were detected in 5 (1.6%) of the 310 samples and identified as Salmonella Infantis (in three samples) and S. Java (in two samples). One of the S. Infantis isolates fell into the same genetic cluster as S. Infantis isolates from three recent human cases of infection; the second fell into another cluster containing two recent cases of infection. Countries of origin recorded on the packaging of the five Salmonella contaminated samples were Hungary (n=1), Ireland (n=2) and the UK (n=2). One S. Infantis isolate was multi-drug resistant (i.e. resistant to three different classes of antimicrobials), while the other Salmonella isolates were each resistant to at least one of the classes of antimicrobials tested. E. coli was detected in 113 samples (36.4%), with counts ranging from <3 to >1100 MPN (Most Probable Number)/g. Almost half of the E. coli isolates (44.5%) were susceptible to all antimicrobials tested. Multi-drug resistance was detected in 20.0% of E. coli isolates. E. coli isolates demonstrating the ESBL (but not AmpC) phenotype were detected in 15 of the 310 samples (4.8%) and the AmpC phenotype alone was detected in two of the 310 samples (0.6%) of chicken samples. Polymerase Chain Reaction (PCR) testing showed that five of the 15 (33.3%) ESBL-producing E. coli carried blaCTX-M genes (CTX-M-1, CTX-M-55 or CTX-M-15), which confer resistance to third generation cephalosporin antimicrobials. One E. coli isolate demonstrated resistance to colistin and was found to possess the mcr-1 gene. The five Salmonella-positive samples recovered from this study, and 20 similar Salmonella-positive samples from a previous UKHSA (2020/2021) study (which had been stored frozen), were subjected to the cooking procedures described on the sample product packaging for fan assisted ovens. No Salmonella were detected in any of these 25 samples after cooking. The current survey provides evidence of the presence of Salmonella in frozen, breaded and battered chicken products in the UK food chain, although at a considerably lower incidence than reported in an earlier (2020/2021) study carried out by PHE/UKHSA as part of an outbreak investigation where Salmonella prevalence was found to be 8.8%. The current survey also provides data on the prevalence of specified AMR bacteria found in the tested chicken products on retail sale in the UK. It will contribute to monitoring trends in AMR prevalence over time within the UK, support comparisons with data from other countries, and provide a baseline against which to monitor the impact of future interventions. While AMR activity was observed in some of the E. coli and Salmonella spp. examined in this study, the risk of acquiring AMR bacteria from consumption of these processed chicken products is low if the products are cooked thoroughly and handled hygienically.