Objective: To clone the gene of plasmid-mediated AmpC beta-lactamase from the plasmid of multiple-drug resistance Klebsiella pneumoniae producing plasmid-mediated AmpC beta-lactamase and demonstrate its mechanism of transmission.
Methods: Plasmids of the transconjugant were extracted and digested with restriction endonuclease HindIII. Taq DNA polymerase was applied to fill the recessed 3' termini, and a single deoxyadenosine was added to the 3' termimi of fragments. Then these fragments were ligated with pGEM-T Easy vector. E. coli DH5alpha containing recombinant plasmid was selected on MacConkey agar plates containing ampicillin and cefoxitin. Insert fragments were sequenced by primer walking. MIC determinations and isoelectric focusing electrophoresis (IFE) were utilized to analyze recombinant.
Results: The recombinant plasmid pT948 containing a 5.2-kb insert was obtained. The inserted fragment contained a bla(DHA-1) and a regulatory gene ampR. The insertion sequence (IS26), qacEDelta1 and sulI genes of the I type integron were obtained near the bla(DHA-1) gene. Recombinant expressed a beta-lactamase with pI of 7.7. MIC determinations showed that recombinant was resistant to cefoxitin and the resistance to ceftazidime could be induced by the cefoxitin.
Conclusion: The plasmid-mediated ampC gene cloned was identified as bla(DHA-1). IS26 observed on the flanks of the bla(DHA-1) maybe relate to the translocation of bla(DHA-1) gene region from the chromosome to plasmid.
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Acta Vet Scand
January 2025
Department of Animal Health and Antibiotic Strategies, Swedish Veterinary Agency, Uppsala, Sweden.
Background: Antibiotic resistant bacteria are a threat to both human and animal health. Of special concern are resistance mechanisms that are transmissible between bacteria, such as extended-spectrum beta-lactamases (ESBL) and plasmid-mediated AmpC (pAmpC). ESBL/AmpC resistance is also of importance as it confers resistance to beta-lactam antibiotics including third generation cephalosporins.
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November 2024
Biomedical Research Center Šalata, University of Zagreb School of Medicine, Department for Clinical Microbiology and Infection Prevention and Control, University Hospital Centre Zagreb, 10000 Zagreb, Croatia.
Heliyon
November 2024
Bapubhai Desaibhai Patel Institute of Paramedical Sciences, Charotar University of Science and Technology, Changa, Gujarat, India.
is a potent human pathogen and a prevalent ESKAPE ( and Enterobacter species). Considerably, becomes a major clinical problem due to numerous AMR genes [extended-spectrum β-lactamase, plasmid-mediated C, carbapenemases, tigecycline resistance, and New Delhi Metallo-β-lactamase-1 (NDM-1)] and can hydrolyze the majority of β-lactam antibiotics. Hence, targeting NDM-1 could be an effective approach to eradicate pathogenesis.
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November 2024
Microbiology and Infectious Diseases, SA Pathology, Adelaide, South Australia, Australia.
Plasmid-mediated AmpC β-lactamases are a cause of acquired cephalosporin resistance in Gram-negative bacteria. However, consensus regarding the optimal detection method is yet to be achieved and varies depending on local epidemiology and laboratory capacity. We determined the acquired genotypic resistance mechanisms of 250 isolates with a positive AmpC screen, defined as cefoxitin MIC ≥ 8 mg/L and a positive AmpC double- disc diffusion test, using in-house designed high-resolution melt PCR, detecting plasmid-acquired genes from the CIT and DHA families.
View Article and Find Full Text PDFSci Rep
November 2024
Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University, PO Box 12211, Giza, Egypt.
The emergence of critical-priority E. coli, carrying a wide array of resistance and virulence factors through food sources, poses a significant challenge to public health. This study aimed to investigate the potential role of oysters sold in Egypt as a source for E.
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