1887

Abstract

. DNA-DNA hybridisation was used to examine 89 isolates of serogroup O138 for toxin gene content and location. Sixty-six isolates encoded toxin genes; 29 were STpa STpb VT2, 24 were VT2, four were STpa STpb, three were STpb VT2, three were STpb VT2 LT and one was STpa. None were K88-, K99- or F41-positive. The VT toxin gene was chromosomally located in all VT isolates tested whereas STpa, STpb and LT were plasmid borne. In co-transfer experiments with pRP4 as the mobilising plasmid, VT2 genes were not transferred to recipient K12 whereas STpa, STpb and LT genes were. Two VT2-positive isolates inhibited pRP4 transfer to K12 by a factor of 10 and rare transconjugants harboured a cointegrate plasmid comprising pRP4 (54kb) and a cryptic host plasmid (145 kb). In a K12 background, the co-integrate had transfer and incompatibility properties of pRP4 whereas in both progenitor O138 backgrounds the co-integrate was transfer inhibited and in one case resolved to give original plasmids.

Loading

Article metrics loading...

/content/journal/jmm/10.1099/00222615-31-4-241
1990-04-01
2019-12-12
Loading full text...

Full text loading...

http://instance.metastore.ingenta.com/content/journal/jmm/10.1099/00222615-31-4-241
Loading
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error