Isolation of Citrate-Utilizing Variants of Escherichia coli from Cattle, Pigs, Chickens, Pigeons and Wild Animals

Lee, Hun-Jun; Choi, Won-Pil

Korean Journal of Veterinary Research 1983;23(2):173-178.

¹Department of Vettrinary Medicine, College of Agriculture, Chungnam National University
²Department of Veiltrinary Medicine, College of Agriculture, Gyeongbug National University

동물유래(動物由來)의 Citrate이용대장균(利用大腸菌) 변이주(變異株)에 관하여

이헌준¹, 최원필²

¹충남대학교 농과대학
²경북대학교 농과대학

Abstract

This paper deals with the isolation of citrate-utilizing variants of Escherichia coli ($Cit^+$ E. coli) from the animals, their biochemical reactivity and antibiotic susceptibility, and whether the citrate utilizing ability is transmissible. One hundred arid twenty-three isolates of $Cit^+$ E. coli were obtained from cattle and pigs. but from other animals, no isolates were obtaied. Antibiotic susceptibility testing of $Cit^+$ E. coli was performed by the agar dilution method, using the following 9 antibiotics, chloramphenicol(CP), tetracycline(TC), streptomycine(SM), kanamycin(KM), colistin(CL), gentamicin(GM), cephaloridine(CR), aminobenzycillin and nalidixic acid(NA). All the variants tested were susceptible to KM, CL, GM, CR and NA. Of all the variants, 80(65%) were resistant to the drugs tested and resistance to TC and SM was most frequent. The transmission of the ability to utilize citrate on Simmons citrate agar at $37^{circ}C$ was demonstrated in 78(67.8%) out of the 115 $Cit^+$ E. coli. There were no significant difference in the transfer rates of citrate utilizing ability between resistant and susceptible variants to above 9 drugs. Of 123 isolates, 8 were lost their citrate utilizing ability, spontaneously.