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Development of selective lysine decarboxylase broth using spectrophotometric assay for Salmonella screening
Khueankhancharoen, J1, Thipayarat, A2.
This study was to demonstrate the application of spectrophotometry for rapid and presumptive
differentiation of Salmonella from other Enterobacteriaceae based on lysine decarboxylase
(LDC) activity. The pH indicator system and cocktails of Salmonella selective inhibitors were
optimized to derive a new selective broth (patent pending no. 1301006577) for Salmonella
screening. Phenol red (PR) was the most suitable pH indicator for the lysine decarboxylase
broth and then derived a new medium, developed lysine decarboxylase broth with phenol red
(dLDBPR). This enrichment medium was able to produce the highest absorbance to differentiate
LDC-positive from -negative samples at 587 nm wavelength and proven to be rapid and useful
approach to identify salmonellae and Enterobacteriaceae from other competitors. The variation
of bacterial growth and broth pH generated from the glucose fermentation and LDC activity
resulted in broth color changes. The most efficient broth was dLDBPR with RVS inhibitors
(dLRVS) enabling fast positive-color shift within 8-10 h and sustained cell viability in all LDCpositive
Salmonella samples. However, dLRVS treatment contained some false LDC-positive
results in some samples with non-Salmonella competitors (Escherichia coli and Klebsiella
pneumoniae). Further optimization of selective inhibitors towards Salmonella detection is in
progress. The assay was proven to be rapid and useful approach to distinguish salmonellae and
Enterobacteriaceae from other competitors.
Affiliation:
- King Mongkut's University of Technology Thonburi (KMUTT), Thailand
- King Mongkut's University of Technology Thonburi (KMUTT), Thailand
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Indexation |
Indexed by |
MyJurnal (2018) |
H-Index
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8 |
Immediacy Index
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0.000 |
Rank |
28/30,Q4(Sciences ) 28/30,Q4(Sciences ) 14/17,Q4(Medical & Health Sciences )
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Indexed by |
Scopus (SCImago Journal Rankings 2016) |
Impact Factor
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- |
Rank |
Q3 (Food Science) |
Additional Information |
0.335 (SJR) |
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