title: R factor types found in Salmonella typhimurium and Escherichia coli isolated from calves in a confined environment.
abstract: Typing of R factors by genetic properties was done with Salmonella typhimurium and Escherichia coli isolated from calves on a feedlot where epizootics of clinical or subclinical calf salmonellosis had repeatedly occurred during 5 years. Forty-nine R factors from S typhimurium were fi- (no fertility inhibition) and spp- (no restriction against phage lambda vir). Twenty-three (46.9%) of them belonged to compatibility group Ialpha and the remainder were nontypable. Fourteen R factors from E coli belonged to different genetic types: fi+ (11=78.6%) and fi- (3=21.4%); spp+ (1=7.1%) and spp- (13=92.9%); compatibility groups FII (5=35.7%), N (1=7.1%), and nontypable (8=57.2%). In contrast to the R factors of S typhimurium, 9 (64.3%) of the 14 R factors of E coli carried resistance against aminobenzyl penicillin with or without kanamycin resistance. The compatibility groups of R factors of S typhimurium seemed to be useful as a subsidiary epizootiologic marker in this feedlot.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D002417:Cattle / Q000382:microbiology; D002418:Cattle Diseases / Q000382:microbiology; D002701:Chloramphenicol / Q000494:pharmacology; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary; D007612:Kanamycin / Q000494:pharmacology; D008297:Male; D010403:Penicillin Resistance; D011815:R Factors; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D007612:Kanamycin; D002701:Chloramphenicol; D000667:Ampicillin; D013752:Tetracycline