title: Estimation of the sensitivity of four sampling methods for Mycoplasma hyopneumoniae detection in live pigs using a Bayesian approach.
abstract: Four sampling techniques for Mycoplasma hyopneumoniae detection, namely nasal swabbing, oral-pharyngeal brushing, tracheo-bronchial swabbing and tracheo-bronchial washing, were compared in naturally infected live pigs. In addition, a quantitative real-time PCR assay for M. hyopneumoniae quantification was validated with the same samples. 60 finishing pigs were randomly selected from a batch of contemporary pigs on a farm chronically affected by respiratory disorders. Each pig was submitted to nasal swabbing, oral-pharyngeal brushing, tracheo-bronchial swabbing and tracheo-bronchial washing. Nested-PCR and real-time PCR assays were performed on all samples. A Bayesian approach was used to analyze the nested-PCR results of the four sampling methods (i.e. positive or negative) to estimate the sensitivity and specificity of each method. M. hyopneumoniae was detected by nested-PCR in at least one sample from 70% of the pigs. The most sensitive sampling methods for detecting M. hyopneumoniae in live naturally infected pigs were tracheo-bronchial swabbing and tracheo-bronchial washing, as compared to oral-pharyngeal brushing and nasal swabbing. Swabbing the nasal cavities appeared to be the least sensitive method. Significantly higher amounts of M. hyopneumoniae DNA were found at the sites of tracheo-bronchial sampling than in the nasal cavities or at the oral-pharyngeal site (p<0.001). There was no difference between the tracheo-bronchial washing and the tracheo-bronchial swabbing results (p>0.05). Our study indicated that tracheo-bronchial swabbing associated with real-time PCR could be an accurate diagnostic tool for assessing infection dynamics in pig herds.
authors.affiliation: Agence Française de Sécurité Sanitaire des Aliments (AFSSA), Unité d'Epidémiologie et de Bien-Etre du Porc, B.P. 53, 22440 Ploufragan, France. c.fablet@ploufragan.afssa.fr
authors.forename: C
authors.initials: C
authors.lastname: Fablet
authors.forename: C
authors.initials: C
authors.lastname: Marois
authors.forename: M
authors.initials: M
authors.lastname: Kobisch
authors.forename: F
authors.initials: F
authors.lastname: Madec
authors.forename: N
authors.initials: N
authors.lastname: Rose
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology; D001431:Bacteriological Techniques / Q000379:methods / Q000662:veterinary*; D001499:Bayes Theorem; D045705:Mycoplasma hyopneumoniae / Q000302:isolation & purification*; D045729:Pneumonia of Swine, Mycoplasmal / Q000175:diagnosis* / Q000382:microbiology / Q000517:prevention & control; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012680:Sensitivity and Specificity; D013552:Swine
chemical_list: D001428:Bacterial Vaccines