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  • PBPs
  • It is based on alterations of the penicillin target enzymes, the penicillin binding proteins (PBPs). (springer.com)
  • To obtain a further understanding to the role of low-molecular-mass penicillin-binding proteins (LMM PBPs) including PBP4, PBP5, PBP6, and PBP7, as well as NagZ and AmpR in ampC regulation of Y. enterocolitica , series of single/multiple mutant strains were systematically constructed and the ampC expression levels were determined by luxCDABE reporter system, reverse transcription-PCR (RT-PCR) and β-lactamase activity test. (frontiersin.org)
  • gene
  • Insertional inactivation of the gene ( mtrD ) encoding the membrane transporter component of the Mtr efflux pump in these transformant strains and in strain FA6140 decreased the MIC of penicillin by 16-fold. (asm.org)
  • Mutations in the coding or promoter region of a gene encoding a transcriptional repressor ( mtrR ) of the mtrCDE operon result in the Mtr property ( 12 , 21 , 23 ). (asm.org)
  • The first determinant in the stepwise acquisition of penicillin resistance is the penA gene, which encodes altered forms of penicillin-binding protein 2 (PBP 2) that have a lower rate of acylation by penicillin ( 15 , 16 , 40 ). (asm.org)
  • Plasmid-mediated gene complexes confer high-level resistance to vancomycin and are often used as targets for molecular detection of VRE. (uspharmacist.com)
  • Resistance to erythromycin was correlated with the presence of the ermB resistance gene. (mdpi.com)
  • Mutant gene variants are passed from parent to offspring, and advantageous mutations spread through future generations in that way. (berkeley.edu)
  • So bacteria acquire genetic variation through random mutation, but, unlike humans or oak trees, they also regularly get new gene variants through the process of horizontal transfer that is, they can pass DNA back and forth to one another directly. (berkeley.edu)
  • In terms of evolution, this means that bacteria do not have to rely on random mutation to produce a beneficial gene variant. (berkeley.edu)
  • Different mutations in the bla ROB-1 gene were obtained during the passages in the presence of the different concentrations of the selective agents. (asm.org)
  • Novel dihydropteroate synthase gene mutation in Pneumocystis jirovecii among HIV-infected patients in India: Putative association with drug resistance and mortality. (annals.org)
  • nalC mutants originate from the wild-type P. aeruginosa PAO1 and are characterized by a mutation in the PA3721 gene [ 8 ]. (hindawi.com)
  • proteins
  • Adam M, Damblon C, Jamin M et al (1991) Acyltransferase activities of the high-molecular-mass essential penicillin-binding proteins. (springer.com)
  • For a long time the main reason for this natural resistance was considered to be the low outer membrane permeability due to the presence of proteins with high molecular mass about 50 kDa [ 5 ]. (hindawi.com)
  • discovery of penicil
  • Until the discovery of penicillin, sulfadiazine and several of its analogues were recognized universally as the drugs of choice in the treatment of pneumococcic pneumonia. (annals.org)
  • resistant
  • In this study, we analyzed the cause of β-lactam resistance in pandemic multidrug-resistant clones. (vanopijnenlab.com)
  • As antimicrobial resistance continues to rise globally, multidrug-resistant (MDR) organisms have posed a significant challenge for clinicians, owing to the dearth of effective therapeutic options to combat them. (uspharmacist.com)
  • When the media report on MRSA and other drug resistant pathogens, they often say that such pathogens have recently "emerged" that they've "developed" resistance or "learned" to evade our drugs. (berkeley.edu)
  • The patient was being treated with vancomycin, and slowly, over the course of a few months and 35 separate mutations, the bacteria evolved into a vancomycin-resistant MRSA strain. (berkeley.edu)
  • An enzyme, known as NDM-1, short for New Delhi metallo-beta-lactamase, makes bacteria resistant to a wide range of penicillins including carbapenems. (medindia.net)
  • The mechanism of colistin resistance (Col r ) in Acinetobacter baumannii was studied by selecting in vitro Col r derivatives of the multidrug-resistant A. baumannii isolate AB0057 and the drug-susceptible strain ATCC 17978, using escalating concentrations of colistin in liquid culture. (asm.org)
  • To overcome this, drug manufacturers developed new derivatives of penicillin, such as methicillin, which were resistant to beta-lactamase. (sciencecodex.com)
  • In the escalating arms race, one particular type of bacteria known as Methicillin-resistant Staphylococcus aureus - MRSA - has developed widespread resistance to this class of drugs. (sciencecodex.com)
  • These mutants: (1) are resistant to two different oxidative stressors, paraquat and the omission of 2-mercaptoethanol, (2) have reduced levels of endogenous reactive oxygen species (ROS), (3) are capable of generating live mice, and (4) transmit the stress resistance phenotype to the mice. (frontiersin.org)
  • The limited spectrum of TKI-resistant mutations in EGFR , which binds to erlotinib in the active conformation, contrasts with a wider range of second-site mutations seen with acquired resistance to imatinib, which binds to ABL and KIT, respectively, in closed conformations. (aacrjournals.org)
  • cephalosporins
  • Such a selective process may lead to the increased use of extended-spectrum cephalosporins or β-lactams plus β-lactamase inhibitors and, eventually, resistance to these agents, which has not previously been observed in H. influenzae . (asm.org)
  • The aim of this study was to evaluate the possible risk of emergence of ROB-1 molecular variants able to hydrolyze oxyimino-cephalosporins such as ceftriaxone or cefotaxime or to develop resistance to β-lactamase inhibitors. (asm.org)
  • Identical
  • Heteroresistance to colistin in A. baumannii has been described ( 17 , 24 ), but it is uncertain whether the basis for this resistance is the presence of a genetically distinct population of cells or whether variation in the regulatory program among genetically identical cells may be sufficient for the expression of resistance. (asm.org)
  • ampicillin
  • In the postvaccination era, ampicillin resistance has dropped to apparently stable levels of 20 to 25% in the United States and 10 to 15% in Spain ( 18 ). (asm.org)
  • deletion
  • Resistance to these agents is most commonly due to a single base pair deletion in the regulatory region of the mtrCDE locus that results in increased expression of the energy-dependent Mtr efflux pump. (asm.org)
  • All the replacement mutations at these sites in PorB1B were correlated with resistance and the deletion mutation showed the highest resistance. (biomedcentral.com)
  • Our initial analysis suggests that patients whose tumors harbor EGFR exon 19 deletion mutations have a longer median survival than those with EGFR L858R point mutation ( 5 ). (aacrjournals.org)
  • molecular
  • The molecular basis for these mutations and how they contribute to antimicrobial resistance are now better understood. (asm.org)
  • We're targeting a resistance mechanism that's shared by a whole bunch of pathogens," said Bruce Geller, professor of microbiology in OSU's College of Science and College of Agricultural Sciences, who's been researching molecular medicine for more than a decade. (medindia.net)
  • impart resistance
  • MET amplification, which can occur as an acquired or de novo resistance mechanism, is a second well-established resistance mechanism known to bypass EGFR inhibition and impart resistance to EGFR TKIs, and as such requires a therapeutic strategy directed at both EGFR and MET ( 3 ). (aacrjournals.org)
  • vitro
  • Our in vitro findings demonstrate that MET D1228V induces resistance to type I MET TKIs through impaired drug binding, while sensitivity to type II MET TKIs is maintained. (aacrjournals.org)
  • When penicillin was shown to be active against pneumococci in vitro, the question of its relationship to the sulfonamides in the treatment of pneumococcic pneumonia became important. (annals.org)
  • occur
  • Over time, additional beneficial mutations that build on the first may occur and begin to spread in the population, allowing more complex traits to evolve as mutations accumulate. (berkeley.edu)