Determination the Pathogenicity of Citrobacter freundii by Using Three Types of Antigens in Najaf City

Abstract

Background:This study has been included stool and urine samples were collected from children under six years of ages collected from three hospitals in Al-Najaf city (Al-Sadr Teaching, Al-Hakeem, and Al-Zahra Maternity and Children) ,Citrobacter freundii isolated from clinical sample. The Suckling Mice Assay (SMA) and Rabbit ligated ileal loop assay (RIL) have been tested to detect production of heat stable and heat labile enterotoxins by bacteria. Material and Methods: Three types of antigens were prepared: Live Bacteria, Crude Enterotoxin and Partially purified enterotoxin(PPET). LD₅₀ for crude and PPET were determined by using white mice (20-25) g, which divided into five groups each group consist of five mice. Results LD₅₀ of bacterial Suspension, crude enterotoxin and PPET in mice was 2.04 × 10⁷ cell/mouse, 66.6 μg/mouse and 46.2 μg/mouse respectively. Conclusion: Citrobacter freundii considered as a potential pathogen that isolated from clinical samples .Bioassay administrated the ability of this species to produce heat stable enterotoxin by using SMA, and heat labile enterotoxin by RIL.

Aim:The aim of this study was to investigate three types of antigens isolated from Citrobacter freundii to determination the pathogencity of this bacteria by LD_50.