Table 2.

Summary of existing tools for assessing agr function.

Assay	Throughputa			EEb	SMc	Referenced
	L	M	H
Agar Plate Assays
CAMP test	✓					Elek and Levy (1950)
β-hemolytic disk assay for δ-hemolysin	✓					Schweizer et al. (2011)
Phospholipase plate assay	✓					Kouker and Jaeger (1987); Laabei et al. (2014)
Agar plate X-GAL test	✓					Nielsen et al. (2010)
Cell culture and ex vivo techniques
Bacterial survival with neutrophils	✓			✓		Schwartz et al. (2009); Pang et al. (2010), White et al. (2014)
Human neutrophil lysis test	✓			✓	✓	Nielsen et al. (2014)
Human keratinocyte cell lysis test	✓			✓	✓	Cech et al. (2012)
Rabbit erythrocyte lysis test	✓			✓	✓	Pang et al. (2010)
Virulence expression on reconstituted human epithelia	✓			✓		Paniagua-Contreras et al. (2014)
Chromatography tools
HPLC quantification of δ-hemolysin	✓	✓		✓	✓	Otto and Gotz (2000); Quave et al. (2011)
LC-MS detection of δ-hemolysin	✓			✓		Somerville et al. (2003)
MALDI-TOF/TOF MS detection of δ-hemolysin	✓			✓		Gagnaire et al. (2012)
HPLC quantification of PSM-α	✓	✓		✓		Chua et al. (2014)
IMS and MALDI-MS/MS characterization of metabolic products and PSMs	✓	✓		✓		Gonzalez et al. (2012)
Quantification of extracellular AIPs by UHPLC/MS	✓	✓		✓		Junio et al. (2013); Roux et al. (2014)
Molecular techniques
Transcriptional analyses by Northern blotting	✓			✓	✓	Gagnaire et al. (2012); Nielsen et al. (2014)
qRT-PCR	✓			✓		Park et al. (2007)
agr::P3 driven GFP reporter assay		✓	✓	✓	✓	Murray et al. (2014); Sully et al. (2014)
agr::P3 driven lux reporter assay		✓	✓	✓	✓	Subrt et al. (2011); Figueroa et al. (2014)
P3-blaZ reporter		✓		✓	✓	Nielsen et al. (2014)
AIP fluorescent reporter competition assay		✓		✓		Kavanaugh et al. (2007); Malone et al. (2007)
Vesicle lysis test		✓		✓		Laabei et al. (2014)

^aTesting throughput: Assay is amenable to the following throughput testing. L, low throughput testing, amenable to a small number of samples. M, medium throughput screening, amenable to 96-well plate assays and not requiring robotic liquid handling systems. H, high throughput screening, amenable to large samples, such as 96-well or 384-well microtiter plates with the assistance of robotics.

^bEE: Requires the use of expensive equipment or core services, such as microplate readers, HPLC, mass spectrometer, and etc.

^cSM: Adapted for testing small molecule inhibitors of the agr system.

^dReferences: Select references are included and this does not represent the full body of literature for each assay.