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 drugefflux 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.

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.

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.