Bacterial pathogens that are multi-drug resistant compromise the effectiveness of treatment when they are the causative agents of infectious disease. These multi-drug resistance mechanisms allow bacteria to survive in the presence of clinically useful antimicrobial agents, thus reducing the efficacy of chemotherapy towards infectious disease. Importantly, active multi-drug efflux is a major mec...

Bacterial efflux pumps confer multidrug resistance by transporting diverse antibiotics from the cell. In Gram-negative bacteria, some of these pumps form multi-protein assemblies that span the cell envelope. Here, we report the near-atomic resolution cryoEM structures of the Escherichia coli AcrAB-TolC multidrug efflux pump in resting and drug transport states, revealing a quaternary structural...

Gram-negative bacteria tend to be more resistant to lipophilic and amphiphilic inhibitors than gram-positive bacteria. Such inhibitors include dyes, detergents, free fatty acids, antibiotics, and other chemotherapeutic agents. This property is used in the selective enrichment of gram-negative bacteria, especially of members of the family Enterobacteriaceae, for example with MacConkey agar (cont...

Quinolone antibiotics constitute a clinically successful and widely used class of broad-spectrum antibiotics; however, the emergence and spread of resistance increasingly limits the use of fluoroquinolones in the treatment and management of microbial disease. In this study, we evaluated the quantitative contributions of quinolone target alteration and efflux pump expression to fluoroquinolone r...

OBJECTIVES Overexpression of efflux pumps in Acinetobacter baumannii is a common mechanism of multidrug resistance in this nosocomial pathogen. Increased efflux pump expression is often assumed from MICs of antibiotics and dyes, without measurement of efflux levels. This study describes a safe, rapid and simple 96-well plate assay that measures the accumulation of a fluorescent dye, Hoechst (H)...

Even though microbial communities can be more effective at degrading xenobiotics than cultured micro-organisms, yet little is known about the strategies that underpin xenobiotic biodegradation by communities. Here, we employ metagenomic community sequencing to explore mechanisms drive development of 49 xenobiotic-degrading communities, which were enriched from 7 contaminated soils or sediments ...

Treponema denticola, a periodontal pathogen, is relatively resistant to human beta-defensins, which are small cationic antimicrobial peptides produced by a number of cells, including the gingival epithelium. Using two independent methods, we previously demonstrated that T. denticola proteases are not responsible for decreased vulnerability to defensins. In this study, we confirmed that the majo...

Pseudomonas aeruginosa shows multidrug resistance, which is mainly attributable to its expression of xenobiotic efflux pumps. However, it is unclear how silent pumps are expressed in clinical isolates. Here, we sequenced the complete genome of P. aeruginosa strain 8380, which was isolated from a human gut.

Bacteria have evolved various types of resistance mechanism to toxic soft metals and metalloids, including cadmium/zinc, copper/silver and arsenic/antimony. Active efflux of the metal is a frequently utilized stratagem to produce resistance by lowering the intracellular concentration to subtoxic levels. Reduction to a less-toxic form or to a form recognized by an efflux system also occurs. Pump...