Antibiotic Efflux Studied with Phenotype MicroArrays

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Antibiotic Efflux Studied with Phenotype MicroArrays

Phenotype MicroArrays are ideally suited to the study of transporters.  Loss of function mutations in drug efflux transporters exhibit hypersensitivity to chemicals that may be substrates of the transporter.  Similarly, overexpression of an efflux transporter may result in relative resistance to the substrates.  Phenotype MicroArray technology can be used to assay transporter function, assign substrates to transporters, and quickly identify multidrug resistance.  The recent papers below show some of the ways that drug efflux pumps have been studied with Biolog’s Phenotype MicroArray antimicrobial assay technology.

Characterization of the MSMEG_2631 Gene (mmp) Encoding a Multidrug and Toxic Compound Extrusion (MATE) Family Protein in Mycobacterium smegmatis and Exploration of Its Polyspecific Nature Using Biolog Phenotype MicroArray
A multidrug and toxic compound extrusion protein was found in the genome of M. smegmatis. Biolog’s Phenotype MicroArrays were used to show that the mutant has increased sensitivity to diverse compounds. Other transporters were shown to have overlapping efflux capabilities. Themmp gene was also shown to be part of an operon.

Elucidating the Regulon of Multidrug Resistance Regulator RarA in Klebsiella pneumoniae
In order to better understand the role of RarA in multidrug resistance, the authors employed DNA microarrays and Phenotype MicroArrays.  Overexpression of RarA results in differential regulation of many genes including transporters.  PM analysis showed relative resistance to several classes of antibiotics.  The results enchance our understanding of the RarA regulon and it’s role in multidrug resistance.

Functional Analysis of Pneumococcal Drug Efflux Pumps Associates the MATE DinF Transporter with Quinolone Susceptibility
Mutants were constructed in ABC, MATE, and MFS transporters.  Mutant susceptibility to 250 inhibitory substances was evaluated with several techniques including Phenotype MicroArray analysis.  The ABC transporter (PatAB) mutant had phenotypes consistent with multidrug resistance while the MATE mutant (DinF) has phenotypes associated with quinoline susceptibility.

Differential Gene Expression by RamA in Ciprofloxacin-Resistant SalmonellaTyphimurium
In the study of RamA mediated antibiotic resistance, Phenotype MicroArrays were used to characterize ramA overexpressing and ramA deletion mutants. Overexpression of ramA upregulated the MDR efflux pump AcrAB-TolC and led to resistance to antibiotics and other toxic agents. Additionally, PM uncovered that the ramA deletion mutant had increased ability to use 10 carbon sources and 10 phosphorus sources. Several PM findings were independently verified.

Phenotype MicroArray Technology
Biolog’s Phentoype MicroArray technology enables researchers to evaluate nearly 2000 phenotypes of a microbial cell in a single experiment. This integrated system of cellular assays, instrumentation and bioinformatics software provides cellular knowledge that complements molecular information, helping you interpret and find the relevant aspects in massive amounts of gene expression or proteomics data. Through comprehensive and precise quantitation of phenotypes, researchers are able to obtain an unbiased perspective of the effect on cells of genetic differences, environmental change, exposure to chemicals or drugs, and more.