GENES ENCODING S-TRIAZINE DEGRADATION ARE PLASMID-BORNE IN KLEBSIELLA-PNEUMONIAE STRAIN-99

Klebsiella pneumoniae strain 99 degrades the s-triazine compound ammel ide through cyanuric acid and biuret to yield urea, carbon dioxide, an d ammonia. The urea and ammonia formed from the degradation of ammelid e or cyanuric acid are utilized as sources of nitrogen for growth of t he organism. When plasmids of the IncI alpha incompatibility group wer e transferred into K. pneumoniae strain 99, the ability to degrade s-t riazine compounds was last at high frequency. Analysis of the plasmid profiles of s-triazine(+) and s-triazine(-) derivatives of strain 99 i ndicated that the largest of the at least five plasmids detected in th is organism carries the genes encoding the s-triazine degradation path way. Conjugal transfer of this plasmid from wild-type strain 99 into a type strain of Klebsiella planticola (ATCC 33531) resulted in exconju gants able to utilize ammelide or cyanuric acid as nitrogen sources. T hus, the genes required for s-triazine degradation are present on a la rge IncI alpha plasmid in K. pneumoniae strain 99.