Next Article in Journal
Real-Time Detection of Staphylococcus Aureus Using Whispering Gallery Mode Optical Microdisks
Next Article in Special Issue
Microfluidic Devices for Forensic DNA Analysis: A Review
Previous Article in Journal
Current-Induced Transistor Sensorics with Electrogenic Cells
Previous Article in Special Issue
Sensing of Salivary Glucose Using Nano-Structured Biosensors
Article Menu

Export Article

Open AccessArticle
Biosensors 2016, 6(2), 19; doi:10.3390/bios6020019

Semi-Quantitative Method for Streptococci Magnetic Detection in Raw Milk

1
INESC–MN Instituto de Engenharia de Sistemas e Computadores—Microsistemas e Nanotecnologias, Rua Alves Redol 9, 1000-029 Lisbon, Portugal
2
CIISA at Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica, 1300-477 Lisbon, Portugal
3
INESC-ID Instituto de Engenharia de Sistemas e Computadores—Investigação e Desenvolvimento, Rua Alves Redol 9, 1000-029 Lisbon, Portugal
4
Visiting from the National Institute of Research and Development for Technical Physics, 47 Mangeron Blvd, Iasi 700050, Romania
5
Instituto Superior Técnico, Physics Department, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
6
International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga, 4715-330 Braga, Portugal
*
Author to whom correspondence should be addressed.
Academic Editor: Domenico Caputo
Received: 21 March 2016 / Revised: 15 April 2016 / Accepted: 21 April 2016 / Published: 27 April 2016
(This article belongs to the Special Issue Advances in Lab-on-Chip Devices)
View Full-Text   |   Download PDF [2445 KB, uploaded 27 April 2016]   |  

Abstract

Bovine mastitis is the most costly disease for dairy farmers and the most frequent reason for the use of antibiotics in dairy cattle; thus, control measures to detect and prevent mastitis are crucial for dairy farm sustainability. The aim of this study was to develop and validate a sensitive method to magnetically detect Streptococcus agalactiae (a Group B streptococci) and Streptococcus uberis in raw milk samples. Mastitic milk samples were collected aseptically from 44 cows with subclinical mastitis, from 11 Portuguese dairy farms. Forty-six quarter milk samples were selected based on bacterial identification by conventional microbiology. All samples were submitted to PCR analysis. In parallel, these milk samples were mixed with a solution combining specific antibodies and magnetic nanoparticles, to be analyzed using a lab-on-a-chip magnetoresistive cytometer, with microfluidic sample handling. This paper describes a point of care methodology used for detection of bacteria, including analysis of false positive/negative results. This immunological recognition was able to detect bacterial presence in samples spiked above 100 cfu/mL, independently of antibody and targeted bacteria used in this work. Using PCR as a reference, this method correctly identified 73% of positive samples for streptococci species with an anti-S. agalactiae antibody, and 41% of positive samples for an anti-GB streptococci antibody. View Full-Text
Keywords: magnetoresistive sensors; magnetic nanoparticle (NP); Streptococcus agalactiae ; Streptococcus uberis ; milk; immunogenic recognition; microfluidic magnetoresistive sensors; magnetic nanoparticle (NP); Streptococcus agalactiae ; Streptococcus uberis ; milk; immunogenic recognition; microfluidic
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Duarte, C.; Costa, T.; Carneiro, C.; Soares, R.; Jitariu, A.; Cardoso, S.; Piedade, M.; Bexiga, R.; Freitas, P. Semi-Quantitative Method for Streptococci Magnetic Detection in Raw Milk. Biosensors 2016, 6, 19.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Biosensors EISSN 2079-6374 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top