Use of mucoid bacterial mutants to circumvent clumping of cells and minicells containing R plasmids derepressed for pilus synthesis.

Clumping of bacteria containing R factors derepressed for pilus synthesis interfered with the separation of cells and minicells. Mucoid derivatives of these bacteria provided the means of preventing clumping and allowing a good separation. This method may be generally useful in dealing with autoagglutination of bacterial cultures.