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Martins M

Characterization of antimicrobial resistance of Salmonella enterica food and animal isolates from Colombia: identification of a qnrB19-mediated quinolone resistance marker in two novel serovars

Ninety-three Salmonella isolates recovered from commercial foods and exotic animals in Colombia were studied. The serotypes, resistance profiles and where applicable the quinolone resistance genes were determined. Salmonella Anatum (n=14), Uganda (19), Braenderup (10) and Newport (10) were the most prevalent serovars, and resistance to tetracycline (18.3%), ampicillin (17.2%) and nalidixic acid (14%) was most […]
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Ion Channel Blockers as Antimicrobial Agents, Efflux Inhibitors, and Enhancers of Macrophage Killing Activity against Drug Resistant Mycobacterium tuberculosis

Given the ability of M. tuberculosis to survive as an intracellular pathogen and its propensity to develop resistance to the existing antituberculosis drugs, its treatment requires new approaches. Here the antimycobacterial properties of verapamil, thioridazine, chlorpromazine, flupenthixol and haloperidol were investigated against a panel of drug resistant M. tuberculosis strains, both in vitro and on human-infected macrophages.
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Targeting the human macrophage with combinations of drugs and inhibitors of Ca2+ and K+ transport to enhance the killing of intracellular multi-drug resistant Mycobacterium tuberculosis (MDR-TB)–a novel, patentable approach to limit the emergence of XDR-TB.

The emergence of resistance in tuberculosis has become a serious problem for the control of this disease. For that reason, new therapeutic strategies that can be implemented in the clinical setting are urgently needed.
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Identification of efflux pump-mediated multidrug-resistant bacteria by the ethidium bromide-agar cartwheel method.

BACKGROUND/AIM:
Bacterial multidrug resistance may be mediated by the overexpression of efflux pumps. Conventional evaluation of efflux activity using efflux pump substrates, such as ethidium bromide, requires specialised instrumentation. The agar-based method, previously reported, has been modified to evaluate as many as twelve bacterial strains and has been termed the ethidium bromide-agar cartwheel method.
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Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent.

Thioridazine (TZ)-induced accumulation of the universal efflux pump substrate ethidium bromide and its subsequent efflux by Salmonella strains with various degrees of overexpressed efflux pumps takes place automatically at pH 7.4, is independent of a metabolic source, is not affected by a proton ionophore and is precluded by palmitic acid.
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Phenothiazines, bacterial efflux pumps and targeting the macrophage for enhanced killing of intracellular XDRTB

Phenothiazines have their primary effects on the plasma membrane of prokaryotes and eukaryotes. Among the components of the prokaryotic plasma membrane affected are efflux pumps, their energy sources, energy providing enzymes such as ATPases, and genes that regulate and code for permeability aspects of the bacterium.
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Exploring the contribution of efflux on the resistance to fluoroquinolones in clinical isolates of Staphylococcus aureus.

BACKGROUND:
Antimicrobial resistance mediated by efflux systems is still poorly characterized in Staphylococcus aureus, despite the description of several efflux pumps (EPs) for this bacterium. In this work we used several methodologies to characterize the efflux activity of 52 S. aureus isolates resistant to ciprofloxacin collected in a hospital in Lisbon, Portugal, in order to understand the role played by these systems in the resistance to fluoroquinolones.
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Inhibitors of mycobacterial efflux pumps as potential boosters for anti-tubercular drugs.

Tuberculosis is one of the major causes of infection across the world. The emergence of multi-, extensively- and totally drug-resistant strains of Mycobacterium tuberculosis contributes to the lack of therapeutic options available.
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Mechanisms of fluoroquinolone resistance in Escherichia coli isolates from food-producing animals.

Eleven multidrug-resistant Escherichia coli isolates (comprising 6 porcine and 5 bovine field isolates) displaying fluoroquinolone (FQ) resistance were selected from a collection obtained from the University Veterinary Hospital (Dublin, Ireland). MICs of nalidixic acid and ciprofloxacin were determined by Etest.
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Mechanisms of Antibiotic Resistance in Salmonella: Efflux Pumps, Genetics, Quorum Sensing and Biofilm Formation.

Multidrug resistance (MDR) to antibiotics presents a serious therapeutic problem in the treatment of bacterial infections. The importance of this mechanism of resistance in clinical settings is reflected in the increasing number of reports of multidrug resistant isolates. In Salmonella enterica, the most common etiological agent of food borne salmonellosis worldwide, MDR is becoming a major concern.
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