Screening of Salmonella Enteritidis Specific O and H Antiserum Potency against Isolated Field Strains of Salmonella from Aegean Region

Background: The increasing prevalence of foodborne human salmonellosis caused by Salmonella Enteritidis is a major foodborne illness throughout the world. Prevention from Salmonella infection is more important in an effective ongoing screening program. The slide agglutination test could be more widely used in developing countries to obtain local and regional data due to its rapid, valid, and relatively cheap and ease application. The main purpose of this study is to characterize Salmonella Enteritidis O and H specific polyclonal antibodies for the detection of Salmonella Enteritidis in field samples by comparing with different species of Salmonella field samples isolated from Aegean Region. Materials, Methods & Results: The polyclonal antibodies used in this study were produced in rabbits as a diagnostic tool in our previous study. A total of 70 Salmonella field samples isolates collected between the years 2009 and 2012 from the layers and broilers poultry farms in Aegean Region were examined against Salmonella Enteritidis O and H specific polyclonal antibodies by slide agglutination test. Isolated Salmonella suspect colonies were subjected to biochemical identification by VITEK 2 compact microbial identification system and further serotyping to identify the serovar was done in the Salmonella National Reference Laboratory of Turkey. Seventy isolates of Salmonella, representing 8 different serotypes were obtained from field samples. In serotyping, the strains together with Salmonella Schwarzengrund, Salmonella Enteritidis, Salmonella Gallinarum, Salmonella Mbandaka, Salmonella Infantis, Salmonella Kentucky, Salmonella Virchow and Salmonella Corvallis were determined in accordance with the Kauffman White Le Minor scheme. The results of Salmonella Enteritidis O and H hyperimmune rabbit sera reactivity with a variety of field strains of Salmonella by slide agglutination test demonstrated that the polyclonal antibodies showed stronger binding capacity to Salmonella Enteritidis without showing cross reactivity between O and H antigen in different field strains. The avidity test result verified a range between 15 and 31 s for O antisera, whereas H antisera showed a range from 15 to 26 s. Discussion: The prevalence of Salmonella may possibly vary from country to country attributable to the geographical properties, sampling strategies and isolation methods performed in the countries. In this study, Salmonella strains were isolated from the Aegean region and polyclonal antibodies were examined for the detection of possible antigenic differences among isolated field strains of Salmonella by using slide agglutination test. Comparing our result with previous studies in literature, the isolated field strains of Salmonella from layers and broilers poultry farms were parallel to those obtained by other researchers. Additionally, according to the study results for the distribution of Salmonella serotype, Salmonella Enteritidis was found the predominant serovar in the Aegean region of Turkey which is also the most frequently isolated serotype worldwide. The results confirm that previously produced polyclonal antibodies were able to identify all Salmonella isolated serotypes without generate any false negative positive results interpreted in accordance with National Reference Laboratory findings. Consequently, the findings show that the prepared polyclonal antibodies can be used in detecting Salmonella Enteritidis from field and clinical samples. From this point of view, importance of the study was clearly put forward that the development of novel diagnostic reagent against Salmonella Enteritidis is very critical in our country since the diagnostic reagents have been exported from various countries with higher cost.