Two different beta-lactamase genes are present in Streptomyces cacaoi.

Two beta-lactamase genes called blaL and blaU have been cloned independently in Liège and in Umeå, from Streptomyces cacaoi. Genes blaL and blaU were found to differ largely in their nucleotide sequences, although the encoded proteins both belonged to the class A of beta-lactamases (active-site serine penicillinases). DNA-hybridization and polymerase chain reaction assays have now demonstrated that both blaL and blaU genes were present in the S. cacaoi strains used in Liège and in Umeå.