Detection ofSalmonella entericaSerovar Typhimurium by Using a Rapid, Array-Based Immunosensor

Abstract

The multianalyte array biosensor (MAAB) is a rapid analysis instrument capable of detecting multiple analytes simultaneously. Rapid (15-min), single-analyte sandwich immunoassays were developed for the detection of Salmonella enterica serovar Typhimurium, with a detection limit of 8 ؋ 10 4 CFU/ml; the limit of detection was improved 10-fold by lengthening the assay protocol to 1 h. S. enterica serovar Typhimurium was also detected in the following spiked foodstuffs, with minimal sample preparation: sausage, cantaloupe, whole liquid egg, alfalfa sprouts, and chicken carcass rinse. Cross-reactivity tests were performed with Escherichia coli and Campylobacter jejuni. To determine whether the MAAB has potential as a screening tool for the diagnosis of asymptomatic Salmonella infection of poultry, chicken excretal samples from a private, noncommercial farm and from university poultry facilities were tested. While the private farm excreta gave rise to signals significantly above the buffer blanks, none of the university samples tested positive for S. enterica serovar Typhimurium without spiking; dose-response curves of spiked excretal samples from university-raised poultry gave limits of detection of 8 ؋ 10 3 CFU/g.

Landscape phage probes for Salmonella typhimurium

“…However, this technique may take as many as 4-5 days to confirm identity. More advanced methods for routine S. typhimurium detection include polymerase chain reaction (PCR) (Kumar et al, 2003;Peng and Shelef, 2001;Tseng et al, 1997), DNA hybridization (Meckes and MacDonald, 2003;Miyamoto et al, 1998;Nastasi et al, 1999), enzyme-linked immunosorbent assay (ELISA) (Tapchaisri et al, 1999) and biosensor-based assays (Kramer and Lim, 2004;Muhammad-Tahir and Alocilja, 2003;Olsen et al, 2003;Taitt et al, 2004) These modern methods offer many potential advantages for the rapid detection of microbial and viral pathogens in environmental samples and food in comparison with traditional long-term culture methods. Despite these advantages, their applications for real time detection and environmental monitoring remain in developmental stages with significant methodological hurdles.…”

The Array Biosensor: Portable, Automated Systems

“…14,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Table 1 provides detailed information on the assays including limits of detection (LOD). The LOD was calculated as the lowest concentration tested which gave a signal 3 standard deviations above the blank.…”

Immunoimmobilization of Living Salmonella for Fundamental Studies and Biosensor Applications

“…Another popularly used linkage is the biotinavidin (streptavidin/neutravidin) system (Fig. 2E), which involves the covalent linking of biotin to antibodies followed by the binding of biotin-labeled antibodies to an avidin layer on the substrate (Taitt et al 2004). Antibodies can also be linked to substrate surfaces through protein A/G/L (Fig.…”