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A Gram- negative rod-shaped bacterium 28/1 isolated by enrichment cultures is able to hydrolyze the amide bond of some phenylurea herbicides and acid anilide herbicides by an inducible amidase. 7.5% of 0.3 mumol.ml-1 linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) are hydrolyzed after 16 hours. 1,1-Dimethylphenylureas are not degraded. Acid anilides are hydrolyzed at a higher rate, 80% of 0.5 mumol.ml-1 N-(4-chlorophenyl)-propionamide and N-(4-nitrophenyl)-propionamide are transformed after 6 hours. The 1-methoxy-1-methyl phenylureas are effective inducers. Linuron-induced cells have a specific activity of 3-4 nmol per mg dry weight per min on the substrate N-(3,4-dichlorophenyl)-propionamide (Propanil). The rate of hydrolysis is influenced by substituents of the aniline ring and by the structure of the side chain of the acid anilides.

6R-[(R)-2-[3-[2-(p-Aminosulfonyl) anilino-4-hydroxy-5-pyrimidinyl] ureido]-2-(4-hydroxyphenyl)acetamido]-penicillanic acid, sodium salt (VX-VC 43), a pyrimidinylureidopenicillin, is a broad-spectrum antibiotic. In vitro it is more active than piperacillin, apalcillin and mezlocillin especially against the following strains; E. coli, Ps. aeruginosa, Ps. stutzeri, K. pneumoniae, Eb. cloacae, Ser. marcescens, Proteus, Sh. flexneri, Y. enterocolitica, Cb. freundii, Acb. calcoaceticus, Bacteroides and Sc. faecalis. The minimal inhibitory concentration (MIC, micrograms/ml), for VX-VC 43 lies between 0.06 and 4 for piperacillin between 0.25 and 16, for apalcillin between 0.25 and 8, and for mezlocillin between 0.5 and 32. The action of VX-VC 43 is bactericidal. In tests against patient-isolates of E. coli (n = 50), Ps. aeruginosa (n = 50), K. pneumoniae (n = 46) and Eb. cloacae (n = 50) VX-VC 43 is clearly more active than Piperacillin. In the case of Ps. aeruginosa 2 micrograms/ml VX-VC 43 inhibits 43.9% of the bacteria and 8.5% with piperacillin; for E. coli 0.25 micrograms/ml inhibits 43.9% with VX-VC 43 and 0% with piperacillin; for K. pneumoniae 4 micrograms/ml inhibits 43.7% with VX-VC 43 and 28% for piperacillin; with Eb. cloacae 2 micrograms/ml inhibits 78% with VX-VC 43 and 4% with piperacillin. Addition of 50% human serum, or a change in culture medium pH (from 6 to 8) has little or no effect on the MIC of VX-VC 43 or piperacillin.(ABSTRACT TRUNCATED AT 250 WORDS)