colistin
Mechanisms of ResistancePotential Mobilization of mcr-10 by an Integrative Mobile Element via Site-Specific Recombination in Cronobacter sakazakiimcr-10 is a newly identified plasmid-borne colistin resistance gene, but its mobilization mechanism remains unclear. In this study, mcr-10 was found on an IncFIB plasmid carrying virulence genes mrkABCDFJ, iucABCD/iutA, and eitCBAD in a Cronobacter sakazakii isolate.
Mechanisms of ResistanceEvolution of Colistin Resistance in the Klebsiella pneumoniae Complex Follows Multiple Evolutionary Trajectories with Variable Effects on Fitness and Virulence CharacteristicsThe increasing prevalence of multidrug-resistant Klebsiella pneumoniae has led to a resurgence in the use of colistin as a last-resort drug. Colistin is a cationic antibiotic that selectively acts on Gram-negative bacteria through electrostatic interactions with anionic phosphate groups of the lipid A moiety of lipopolysaccharides (LPSs). Colistin resistance in...
Experimental TherapeuticsActivity of Tigecycline or Colistin in Combination with Zidovudine against Escherichia coli Harboring tet(X) and mcr-1Alternative therapeutic options are urgently needed against multidrug-resistant Escherichia coli infections, especially in situations of preexisting tigecycline and colistin resistance. Here, we investigated synergistic activity of the antiretroviral drug zidovudine in combination with tigecycline or colistin against...
Experimental TherapeuticsImipenem/Cilastatin/Relebactam Alone and in Combination against Pseudomonas aeruginosa in the In Vitro Pharmacodynamic ModelCombination therapy may enhance imipenem/cilastatin/relebactam’s (I/R) activity against Pseudomonas aeruginosa and suppress resistance development. Human-simulated unbound plasma concentrations of I/R at 1.25 g every 6 h (h), colistin at 360 mg daily, and amikacin at 25 mg/kg daily were reproduced alone and in combination against six imipenem-nonsusceptible...
Epidemiology and SurveillanceNational Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and...
Epidemiology and SurveillanceThe mcr-9 Gene of Salmonella and Escherichia coli Is Not Associated with Colistin Resistance in the United StatesReports of transmissible colistin resistance show the importance of comprehensive colistin resistance surveillance. Recently, a new allele of the mobile colistin resistance (mcr) gene family designated mcr-9, which shows variation in genetic context and colistin susceptibility, was reported. We tested over 100 Salmonella enterica and...
Mechanisms of ResistanceA Novel Deletion Mutation in pmrB Contributes to Concurrent Colistin Resistance in Carbapenem-Resistant Escherichia coli Sequence Type 405 of Clinical OriginWe report the first clinical Escherichia coli strain EC3000 with concomitant chromosomal colistin and carbapenem resistance. A novel in-frame deletion, Δ6-11 (RPISLR), in pmrB that contributes to colistin resistance was verified using recombinant DNA techniques. Although being less fit than the wild-type (WT) strain or EC3000 revertant (chromosomal...
PharmacologyEvaluation of Dose-Fractionated Polymyxin B on Acute Kidney Injury Using a Translational In Vivo Rat ModelWe investigated dose-fractionated polymyxin B (PB) on acute kidney injury (AKI). PB at 12 mg of drug/kg of body weight per day (once, twice, and thrice daily) was administered in rats over 72 h. The thrice-daily group demonstrated the highest KIM-1 increase (P = 0.018) versus that of the controls (P = 0.99) and histopathological damage (P = 0.013). A three-compartment model best described the data (bias, 0....
PharmacologyActivity of Antibiotics against Pseudomonas aeruginosa in an In Vitro Model of Biofilms in the Context of Cystic Fibrosis: Influence of the Culture MediumPseudomonas aeruginosa is a major cause of respiratory biofilm-related infections in patients with cystic fibrosis. We developed an in vitro pharmacodynamic model to study the activity of antipseudomonal antibiotics against PAO1 biofilms grown in artificial sputum medium with agar [ASM(+)] versus that against biofilms grown in Trypticase soy broth...
Experimental TherapeuticsEfficacy of Ceftolozane-Tazobactam in Combination with Colistin against Extensively Drug-Resistant Pseudomonas aeruginosa, Including High-Risk Clones, in an In Vitro Pharmacodynamic ModelCombination therapy is an attractive therapeutic option for extensively drug-resistant (XDR) Pseudomonas aeruginosa infections. Colistin has been the only treatment available for these infections for many years, but its results are suboptimal. Ceftolozane-tazobactam (C/T) is a newly available therapeutic option that has shown good antipseudomonal activity, even...