The structures of an RNA component of ribonuclease P (RNase P RNA) were examined for Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio carchariae, Vibrio natriegens, Vibrio campbellii, Vibrio proteolyticus, Vibrio pelagius and Vibrio harveyi to clearly determine their genetic differences. The RNase P RNAs ranged from 382 to 454 nucleotides (nt) in size, and were remarkably different from each other in the structure of two helices, P3 and P12. The P3 helices were comprised of tandem repeats of a palindromic sequence (24 nt), resulting in the longitudinal repetition of a stem structure. The number of repetitions ranged from four in V. harveyi, to one in both V. alginolyticus and V. proteolyticus. The genes for the RNase P RNAs of all species were located between two open reading frames, the amino acid sequences of which were similar to the hypothetical proteins located at 70.92 and 1.94 min in the Escherichia coli chromosome.
ABSTRACT Tetracycline-resistant (Tet r ) bacteria were isolated from fishes collected at three different fish farms in the southern part of Japan in August and September 2000. Of the 66 Tet r gram-negative strains, 29 were identified as carrying tetB only. Four carried tetY , and another four carried tetD . Three strains carried tetC , two strains carried tetB and tetY , and one strain carried tetC and tetG . Sequence analyses indicated the identity in Tet r genes between the fish farm bacteria and clinical bacteria: 99.3 to 99.9% for tetB , 98.2 to 100% for tetC , 99.7 to 100% for tetD , 92.0 to 96.2% for tetG , and 97.1 to 100% for tetY . Eleven of the Tet r strains transferred Tet r genes by conjugation to Escherichia coli HB-101. All transconjugants were resistant to tetracycline, oxycycline, doxycycline, and minocycline. The donors included strains of Photobacterium , Vibrio , Pseudomonas , Alteromonas , Citrobacter , and Salmonella spp., and they transferred tetB , tetY , or tetD to the recipients. Because NaCl enhanced their growth, these Tet r strains, except for the Pseudomonas , Citrobacter , and Salmonella strains, were recognized as marine bacteria. Our results suggest that tet genes from fish farm bacteria have the same origins as those from clinical strains.
ABSTRACT Six strains of multidrug-resistant Stenotrophomonas maltophilia were isolated from cultured yellowtail. The strains were divided into two clusters based on the 16S rRNA genes, and all of them contained L1 metallo-β-lactamase and L2 β-lactamase genes. Differences in the intercluster divergence between the lactamase genes suggest that horizontal transfer of the genes occurred.
