title: Simultaneous Quantification and Differentiation of Streptococcus suis Serotypes 2 and 9 by Quantitative Real-Time PCR, Evaluated in Tonsillar and Nasal Samples of Pigs.
abstract: Invasive Streptococcus suis (S. suis) infections in pigs are often associated with serotypes 2 and 9. Mucosal sites of healthy pigs can be colonized with these serotypes, often multiple serotypes per pig. To unravel the contribution of these serotypes in pathogenesis and epidemiology, simultaneous quantification of serotypes is needed. A quantitative real-time PCR (qPCR) targeting cps2J (serotypes 2 and 1/2) and cps9H (serotype 9) was evaluated with nasal and tonsillar samples from S. suis exposed pigs. qPCR specifically detected serotypes in all pig samples. The serotypes loads in pig samples estimated by qPCR showed, except for serotype 9 in tonsillar samples (correlation coefficient = 0.25), moderate to strong correlation with loads detected by culture (correlation coefficient > 0.65), and also in pigs exposed to both serotypes (correlation coefficient > 0.75). This qPCR is suitable for simultaneous differentiation and quantification of important S. suis serotypes.
authors.affiliation: Faculty of Veterinary Medicine, Department of Farm Animal Health, Utrecht University, P.O. Box 80.151, 3508 TD Utrecht, The Netherlands. c.n.t.dekker@uu.nl.|Faculty of Veterinary Medicine, Department of Infectious Diseases and Immunology, Utrecht University, P.O. Box 80.165, 3508 TD Utrecht, The Netherlands. c.n.t.dekker@uu.nl.
authors.forename: Niels
authors.initials: N
authors.lastname: Dekker
authors.affiliation: Faculty of Veterinary Medicine, Department of Farm Animal Health, Utrecht University, P.O. Box 80.151, 3508 TD Utrecht, The Netherlands. a.j.j.m.daemen@uu.nl.
authors.forename: Ineke
authors.initials: I
authors.lastname: Daemen
authors.affiliation: Faculty of Veterinary Medicine, Department of Infectious Diseases and Immunology, Utrecht University, P.O. Box 80.165, 3508 TD Utrecht, The Netherlands. k.verstappen@uu.nl.
authors.forename: Koen
authors.initials: K
authors.lastname: Verstappen
authors.affiliation: Central Veterinary Institute of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands. astrid.degreeff@wur.nl.
authors.forename: Astrid
authors.initials: A
authors.lastname: de Greeff
authors.affiliation: Central Veterinary Institute of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands. hilde.smith@wur.nl.
authors.forename: Hilde
authors.initials: H
authors.lastname: Smith
authors.affiliation: Faculty of Veterinary Medicine, Department of Infectious Diseases and Immunology, Utrecht University, P.O. Box 80.165, 3508 TD Utrecht, The Netherlands. b.duim@uu.nl.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Duim
keywords: S. suis; Streptococcus suis; cps; nose; pig; qPCR; serotype 2; serotype 9; tonsil