Screening for Salmonella with a murine monoclonal antibody M105 detects both Felix O1 bacteriophage sensitive and resistant Salmonella strains.

Ten Felix O1 (FO1) bacteriophage sensitive Salmonella strains as well as their phage resistant derivates together with 39 strains of FO1-resistant Salmonella were tested for their reactivities with a murine monoclonal antibody, M105, by indirect whole cell and competitive ELISA. All FO1 phage sensitive and 48 of the 49 FO1-resistant Salmonella strains were found to react with M105. The single Salmonella strain not reacting with M105 was a FO1 resistant derivative selected by exposing the sensitive parent strain to the phage. This M105-negative and FO1-resistant strain was also found to be a rough mutant without O-antigens and possibly lacks the terminal LPS core sugars which form the M105 reactive epitope.