Appearance of enterotoxigenic Escherichia coli in piglets with diarrhea in connection with feed changes.
Twelve weaned piglet (3-week-old) were divided into three groups according to time of feed change and observed for diarrhea during the time they were 3 to 8 weeks of age. A total of 553 strains of Escherichia coli were isolated from rectal fecal samples and examined for heat-labile (LT) and heat-stable (ST) enterotoxins, pilus antigens (K88, K99, and 987P), hemolysin (Hly), raffinose utilization (Raf) and drug resistance. Enterotoxins and/or hemolytic E. coli strains appeared in the rectal feces of 5- to 6-week-old piglets with diarrhea in connection with feed change and changing temperatures. Most of the isolates showed multiple drug resistance to sulfonamides (Sa), streptomycin (Sp), ampicillin, and/or mercury. Enterotoxigenic E. coli isolates represented four phenotypes: K88+.LT+.Hly+.Raf+.(SaSmCpTcKmSp) (12 strains), K99+.ST+.Raf+.(TcKm) (7 strains), ST+.Raf+.(TcKm) (7 strains), and ST.+(SaSmKm) (25 strains). The drug resistance determinants were transferable concurrently and some of them mobilized the determinants for K88, LT, Hly, and Raf to an E. coli C strain.
D000818:Animals; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D010641:Phenotype; D013552:Swine / Q000382:microbiology; D013553:Swine Diseases / Q000382:microbiology*