Impact of Phage Therapy on Pseudomonas syringae pv. syringae and Plant Microbiome Dynamics Through Coevolution and Field Experiments.

Bacteriophages (phages) are viruses that infect and lyse bacteria and have the potential for controlling bacterial diseases. Isolation of phages targeting the cherry pathogen Pseudomonas syringae pv. syringae (Pss) led to five distinct phage genotypes.

Coevolutionary analysis of Pseudomonas syringae-phage interactions to help with rational design of phage treatments.

Treating plant bacterial diseases is notoriously difficult because of the lack of available antimicrobials. Pseudomonas syringae pathovar syringae (Pss) is a major pathogen of cherry (Prunus avium) causing bacterial canker of the stem, leaf and fruit, impacting productivity and leading to a loss of trees. In an attempt to find a treatment for this disease, naturally occurring bacteriophage (phage) that specifically target Pss is being investigated as a biocontrol strategy.

Absence, loss-of-function, or inhibition of Escherichia coli AcrB does not increase expression of other efflux pump genes supporting the discovery of AcrB inhibitors as antibiotic adjuvants.

Objectives: To determine whether expression of efflux pumps and antibiotic susceptibility are altered in Escherichia coli in response to efflux inhibition.

Methods: The promoter regions of nine efflux pump genes (acrAB, acrD, acrEF, emrAB, macAB, cusCFBA, mdtK, mdtABC, mdfA) were fused to gfp in pMW82 and fluorescence from each reporter construct was used as a measure of the transcriptional response to conditions in which AcrB was inhibited, absent or made non-functional. Expression was also determined by RT-qPCR.

New Multidrug Efflux Inhibitors for Gram-Negative Bacteria.

Active efflux of antibiotics preventing their accumulation to toxic intracellular concentrations contributes to clinically relevant multidrug resistance. Inhibition of active efflux potentiates antibiotic activity, indicating that efflux inhibitors could be used in combination with antibiotics to reverse drug resistance. Expression of by serovar Typhimurium increases in response to efflux inhibition, irrespective of the mode of inhibition.

Chlorpromazine and Amitriptyline Are Substrates and Inhibitors of the AcrB Multidrug Efflux Pump.

Efflux is an important mechanism in Gram-negative bacteria conferring multidrug resistance. Inhibition of efflux is an encouraging strategy to restore the antibacterial activity of antibiotics. Chlorpromazine and amitriptyline have been shown to behave as efflux inhibitors.

Strategies to combat antimicrobial resistance: anti-plasmid and plasmid curing.

Antimicrobial resistance (AMR) is a global problem hindering treatment of bacterial infections, rendering many aspects of modern medicine less effective. AMR genes (ARGs) are frequently located on plasmids, which are self-replicating elements of DNA. They are often transmissible between bacteria, and some have spread globally.

Recovery of Staphylococcus aureus in Gray Mugil cephalus Roe (Bottarga): Investigation by an Integrated Cultural/Molecular Approach.

In the Mediterranean area, salted and dried roe from the gray Mugil cephalus "bottarga" represent a speciality food with great commercial value. Bottarga is currently produced by a traditional handmade process and, the risk of human bacterial contamination during its manufacturing is still unknown; in this perspective the foodborne pathogen Staphylococcus aureus could potentially contaminate this product due to poor sanitation or bad handling during processing. The aim of this work is: to evaluate the contamination level of foodborne pathogens at different product manufacturing stages and, in addition, to describe a fast and realizable method for the rapid detection of S.

Mutations upstream of fabI in triclosan resistant Staphylococcus aureus strains are associated with elevated fabI gene expression.

Background: The enoyl-acyl carrier protein (ACP) reductase enzyme (FabI) is the target for a series of antimicrobial agents including novel compounds in clinical trial and the biocide triclosan. Mutations in fabI and heterodiploidy for fabI have been shown to confer resistance in S. aureus strains in a previous study.

Evaluation of reduced susceptibility to quaternary ammonium compounds and bisbiguanides in clinical isolates and laboratory-generated mutants of Staphylococcus aureus.

The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride and chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus. Both compounds showed unimodal MIC and MBC distributions (2 and 4 or 8 mg/liter, respectively) with no apparent subpopulation with reduced susceptibility. To investigate further, all isolates were screened for qac genes, and 39 of these also had the promoter region of the NorA multidrug-resistant (MDR) efflux pump sequenced.

Functional analysis of pneumococcal drug efflux pumps associates the MATE DinF transporter with quinolone susceptibility.

The pneumococcal chromosome encodes about 140 transporters, many of which are predicted to be involved in efflux. In order to critically evaluate pneumococcal efflux, a series of transporter mutants were constructed, and their phenotypes were assayed by disk diffusion, microdilution drug susceptibility testing (MIC testing), growth of cultures at sub-MIC concentrations, and phenotype microarray analysis. Mutants with mutations in seven ATP binding cassette (ABC) transporters, three multiantimicrobial extrusion (MATE) family efflux pumps, and one major facilitator superfamily (MFS) transporter were obtained in Streptococcus pneumoniae strain DP1004.

A novel resistance mechanism to triclosan that suggests horizontal gene transfer and demonstrates a potential selective pressure for reduced biocide susceptibility in clinical strains of Staphylococcus aureus.

The widely used biocide triclosan selectively targets FabI, the NADH-dependent trans-2-enoyl-acyl carrier protein reductase, which is an important target for narrow-spectrum antimicrobial drug development. In relation to the growing concern about biocide resistance, we compared in vitro mutants and clinical isolates of Staphylococcus aureus with reduced triclosan susceptibility. Clinical isolates of S.

Evaluation of antimicrobial-antibiofilm activity of a hydrogen peroxide decontaminating system used in dental unit water lines.

A dental unit water line (DUWL) equipped with a device designed to automatically and continually flush a bacteriostatic solution of hydrogen peroxide (WHE) and a discontinuous disinfecting system (BIOSTER) was evaluated. In the first instance a preliminary sensitivity test on a large number of microorganisms (bacteria and fungi) was tried with a H(2)O(2) range from 100 to 800 ppm. The bacteria frequently reported in DUWL (including Pseudomonas spp, Streptococcus spp.

Usefulness of real time PCR for the differentiation and quantification of 652 and JP2 Actinobacillus actinomycetemcomitans genotypes in dental plaque and saliva.

Background: The aim of our study is to describe a fast molecular method, able to distinguish and quantize the two different genotypes (652 and JP2) of an important periodontal pathogen: Actinobacillus actinomycetemcomitans. The two genotypes show differences in the expression of an important pathogenic factor: the leukotoxin (ltx). In order to evidence this, we performed a real time PCR procedure on the ltx operon, able to recognize Aa clinical isolates with different leukotoxic potentials.