A multiplexed, indirect enzyme-linked immunoassay for the detection and differentiation of E. coil from other Enterobacteriaceae and P. aeruginosa from other glucose non-fermenters

Gram-negative bacteria (GNB) are important causes of community (CA) and hospital (HA)-associated infections. Here we describe the development of an indirect ELISA (I-ELISA), which can be used to detect and differentiate the Enterobacteriaceae Escherichia coil, and glucose non-fermenter Pseudomonas aeruginosa from other GNB species. The I-ELISA utilizes six antibodies for bacterial speciation, which were grouped according to their bacterial targets; Enterobacteriaceae (SL-EntA and CH1810 mAb), Escherichia coli (SL-EcA and 6103-46 mAb), Pseudomonas aeruginosa (SL-PaA and SL-PaB). The six, anti-GNB antibodies were first screened against a panel of well-characterized clinical GNB isolates to optimize assay conditions and to determine individual antibody sensitivity and specificity. When tested against a diverse, blinded panel of 94 GNB clinical isolates, the I-ELISA exhibited the following sensitivity/specificity for each target: Enterobacteriaceae (94.4%/95%), E. coli (82.6%/88.7%), P. aeruginosa (83.3%/96%). An I ELISA to detect and differentiate the most common GNB pathogens offers advantage in terms of simplicity over diagnostic tests currently used in most clinical settings.