Detection and enumeration of Streptococcus agalactiae from bovine milk samples by real-time polymerase chain reaction

de Carvalho, Nara Ladeira, Goncalves, Juliano Leonel, Botaro, Bruno Garcia and Prada Silva, Luis Felipe (2015) Detection and enumeration of Streptococcus agalactiae from bovine milk samples by real-time polymerase chain reaction. Current Microbiology, 71 3: 363-372. doi:10.1007/s00284-015-0855-1


Author de Carvalho, Nara Ladeira
Goncalves, Juliano Leonel
Botaro, Bruno Garcia
Prada Silva, Luis Felipe
Title Detection and enumeration of Streptococcus agalactiae from bovine milk samples by real-time polymerase chain reaction
Formatted title
Detection and enumeration of Streptococcus agalactiae from bovine milk samples by real-time polymerase chain reaction
Journal name Current Microbiology   Check publisher's open access policy
ISSN 0343-8651
1432-0991
Publication date 2015-09-01
Sub-type Article (original research)
DOI 10.1007/s00284-015-0855-1
Open Access Status Not yet assessed
Volume 71
Issue 3
Start page 363
End page 372
Total pages 10
Place of publication New York, NY United States
Publisher Springer New York
Language eng
Formatted abstract
The aim of this study was to evaluate the use of real-time polymerase chain reaction (qPCR) combined with DNA extraction directly from composite milk and bulk tank samples for detection and enumeration of Streptococcus agalactiae (SAG) causing subclinical mastitis. Dilutions of sterile reconstituted skim milk inoculated with SAG ATCC 13813 were used to establish a standard curve (cfu/mL) for the qPCR assay targeting SAG. The analytical sensitivity and repeatability of the qPCR assay were determined. Bulk tank (BTM; n = 38) and composite milk samples (CM; n = 26) collected from lactating cows with positive isolation of SAG were submitted to the qPCR protocol and SAG plate counting, with results from both methods compared. Amplification of DNA was not possible in two out of 64 samples, indicating that qPCR was able to detect SAG in 96 and 97 % of BTM and CM samples, respectively. The inter-assay coefficient of variation was <5 %, showing that the technique had adequate repeatability. The qPCR protocol can be a high-throughput and rapid diagnostic assay to accurately detect SAG from BTM and CM samples compared with conventional microbiological culture method. However, the evaluated qPCR protocol is not accurate for enumerating SAG in milk samples, probably due to quantification of DNA of non-viable cells.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Queensland Alliance for Agriculture and Food Innovation
 
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Created: Mon, 13 Mar 2017, 14:13:38 EST by Luis Prada E Silva on behalf of Centre for Animal Science