Role of gut microbiota in travel-related acquisition of extended spectrum β-lactamase-producing Enterobacteriaceae.

Background: International travel could facilitate the spread of antimicrobial-resistant bacteria including extended spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E). Previous studies, which attempted to understand the role of gut microbiota in the acquisition of antimicrobial resistant bacteria during international travels, are limited to western travellers.

Methods: We established a prospective cohort of 90 Hong Kong travellers to investigate gut microbiota determinants and associated risk factors for the acquisition of ESBL-E.

Two Regulators, PA3898 and PA2100, Modulate the Pseudomonas aeruginosa Multidrug Resistance MexAB-OprM and EmrAB Efflux Pumps and Biofilm Formation.

It is generally believed that the biofilm matrix itself acts as a molecular sieve or sink that contributes to significant levels of drug resistance, but it is becoming more apparent that multidrug efflux pumps induced during biofilm growth significantly enhance resistance levels. We present here a novel transcriptional regulator, PA3898, which controls biofilm formation and multidrug efflux pumps in A mutant of this regulator significantly reduced the ability of to produce biofilm and affected its fitness and pathogenesis in and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA3898 modulates essential virulence genes/pathways, including multidrug efflux pumps and phenazine biosynthesis.

Novel dual regulators of Pseudomonas aeruginosa essential for productive biofilms and virulence.

Gene regulation network in Pseudomonas aeruginosa is complex. With a relatively large genome (6.2 Mb), there is a significant portion of genes that are proven or predicted to be transcriptional regulators.

Simultaneous overexpression of multidrug efflux pumps in Pseudomonas aeruginosa non-cystic fibrosis clinical isolates.

The purpose of this study was to examine expression and regulation of 6 multidrug efflux systems, including MexAB-OprM, MexCD-OprJ, MexEF-OprN, MexXY, MexJK, and MexVW, in 13 non-cystic fibrosis (CF) clinical isolates of Pseudomonas aeruginosa. These isolates displayed a high level of resistance to many clinically important antibiotics. Some isolates simultaneously overexpressed up to 4 different Mex systems, as determined by quantitative real-time reverse transcription PCR.

Aminoglycoside resistance mechanisms in Pseudomonas aeruginosa isolates from non-cystic fibrosis patients in Thailand.

This study aimed to examine aminoglycosides (AMGs) resistance mechanisms, including the AMG-modifying enzyme genes, mexXY, rplY, nuoG, and galU, in the Pseudomonas aeruginosa non-cystic fibrosis (CF) isolates in Thailand. One hundred P. aeruginosa isolates from non-CF patients were examined for susceptibility to AMGs and for the presence of 10 AMG-modifying enzyme genes.

Class 1 integrons in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from clinical isolates.

Resistance to various antimicrobial agents is an increasing problem in Pseudomonas aeruginosa and Acinetobacter baumannii infections. In this study, the roles of integrons were examined in 101 P. aeruginosa isolates and 176 A.

Contribution of the MexXY multidrug efflux pump and other chromosomal mechanisms on aminoglycoside resistance in Pseudomonas aeruginosa isolates from canine and feline infections.

As study of multidrug efflux pumps is a crucial step for development of efflux pump inhibitors for treatment of Pseudomonas aeruginosa infection, the objective of this study was to examine the contribution of the MexXY multidrug efflux systems and other chromosomal mechanisms in aminoglycoside (AMG) resistance in P. aeruginosa isolated from dogs and cats. Thirteen Pseudomonas aeruginosa isolates from canine and feline infections were examined for contribution of the MexXY multidrug efflux pump and four other chromosomally-encoded genes including PA5471, galU, nuoG and rplY to AMG resistance.