ORIGINAL ARTICLE Comparison of the VIDAS Ò system, FTA Ò filter-based PCR and culture on SM ID for detecting Salmonella in Dermanyssus gallinae C. Valiente Moro 1 , S. Desloire 1 , C. Vernozy-Rozand 2 , C. Chauve 1 and L. Zenner 1 1 UMR 958 ENVL ⁄ INRA Protozoaires Ente ´ ricoles et Parasites des Volailles, Ecole Nationale Ve ´ te ´ rinaire de Lyon, Marcy l’Etoile, France 2 Unite ´ de Microbiologie Alimentaire et Pre ´ visionnelle, Ecole Nationale Ve ´ te ´ rinaire de Lyon, Marcy l’Etoile, France Introduction The haematophagous ectoparasite, the poultry red mite Dermanyssus gallinae (DeGeer 1778) is the most import- ant in terms of widespread pest of laying hens in Europe (Chauve 1998). It parasites its hosts only during blood meals and causes anaemia, dermatitis, weight loss and decreased egg production. Although its hosts are mainly poultry, it is an ubiquitous pest and can also parasite mammals, including man. It has also been demonstrated or suspected of being a vector of many pathogens (Valiente Moro et al. 2005). Salmonella is the bacteria responsible for one of the most widespread major zoo- noses in the world (Lacey 1993). As poultry is one of the most important reservoirs for Salmonella, preventing the food-borne transmission of diseases to humans has become an urgent priority on poultry farms (Rodrigue et al. 1990; Calnek 1997). More and more investigations have emphasized the role of wildlife species such as litter beetles, houseflies and nematodes, in the transmission or persistence of salmonellae in poultry. As Salmonella Gal- linarum was isolated from D. gallinae collected from a poultry farm with pullurosis-typhus, the presence of mites and recurrent Salmonella contamination in poultry flocks Keywords Dermanyssus gallinae, PCR, poultry, Salmonella, SM ID, VIDAS Ò . Correspondence Claire Valiente Moro, UMR 958 ENVL ⁄ INRA Protozoaires Ente ´ ricoles et Parasites des Volailles, Ecole Nationale Ve ´ te ´ rinaire de Lyon, 1 avenue Bourgelat, 69280 Marcy l’Etoile, France. E-mail: valienteclaire@yahoo.fr 2005 ⁄ 1454: received 9 December 2005, revised and accepted 25 October 2006 doi:10.1111/j.1472-765X.2007.02119.x Abstract Aims: To compare different analytical methods for detecting Salmonella in Der- manyssus gallinae. Methods and Results: The detection limit of three Salmonella detection methods [Vitek immunodiagnostic assay (VIDAS Ò ) Salmonella immuno-concentration ⁄ immunoassay, FTA Ò filter-based PCR, and Salmonella detection and identifica- tion medium (SM ID) preceded by a pre-enrichment step] was evaluated by crushing mites in serial dilutions of pure cultures of Salmonella enterica ssp. Enterica serotype Enteritidis. Each method was then compared for its ability to detect Salmonella in artificially contaminated mites. In 105 mites artificially engorged with Salm. Enteritidis-contaminated blood, Salmonella was isolated from 68 samples of the samples cultured on SM ID and tests were positive for Salmonella using FTA filter-based PCR and VIDAS in 77 and 65 samples, respect- ively. Using SM ID as our reference method, specificities and sensitivities were 97% and 94% and 73% and 98Æ5% for VIDAS and PCR, respectively. Conclusions: Each method allowed the detection of Salmonella in contamin- ated mites and is usable for screening mites. PCR is more sensitive but less spe- cific than VIDAS for detecting Salmonella. Significance and Impact of the Study: This is the first time that the VIDAS has been used to detect pathogens in vectors. The development of analytical meth- ods for Salmonella detection in mites is a necessary step in the study of the role of D. gallinae as a vector of salmonellae and to check the contamination of D. gallinae in poultry facilities. Letters in Applied Microbiology ISSN 0266-8254 Journal compilation ª 2007 The Society for Applied Microbiology, Letters in Applied Microbiology 44 (2007) 431–436 No claim to original French government works 431