Chloramphenicol Resistance Plasmids in Escherichia coli Isolated from Diseased Piglets

Abstract

The plasmids in 19 chloramphenicol-resistant Escherichia coli strains of three pig pathogenic antigen types were studied in conjugation and transduction experiments. The plasmids had identical resistance patterns: streptomycin, spectinomycin, sulfonamides, and chloramphenicol (Sm, Sp, Su, Cm) and belonged to IncFII. One plasmid carried ampicillin resistance in addition. Restriction enzyme analysis of the deoxyribonucleic acid from five of the plasmids originating from the same herd showed that their digestion patterns with EcoRI were indistinguishable. EcoRI cleaved the deoxyribonucleic acid of a sixth plasmid from the same herd and displayed nine of the ten bands of the other five plasmids plus an additional six. It appears that the five plasmids with identical restriction patterns have a common origin and may be copies of the same plasmid from which the sixth may have developed. Four strains carried two plasmids each. In two of these strains, a plasmid with a tetracycline marker (Tc), or possibly the tetracycline marker alone, recombined frequently with the Sm Sp Su Cm plasmid without destroying any known function of the latter. The possibility that Tc is carried on a translocation sequence is discussed.

Incidence of antibiotic-resistant Escherichia coli associated with frozen chicken carcasses and characterization of conjugative R plasmids derived from such strains

“…Although this aspect was not further investigated, it seemed likely that the original transfer had been the result of mobilization of a nonconjugative R plasmid by a cohabiting conjugative plasmid in the same cell. Certainly, the likelihood that many of the wild-type strains harbored more than one R plasmid was evidenced by the recovP ery of the plasmid pairs pVS118 and pVS121 (total of three resistances), and pVS108 and pVS115 (total of four resistances) from the same bacterium, and by the fact that, although many strains displayed multiple resistances, only 1 (15), from pigeons in Japan (25), and from breeding hens in France (6), respectively. Moreover, A and A-like plasmids (Inc L) were common in Salmonella typhinurium type 29 from human and bovine origin in England in the 1960s (1).…”

Quantifying Attachment and Antibiotic Resistance of Escherichia coli from Conventional and Organic Swine Manure

“…Chloramphenicol is functionally similar to a macrolide in that it affects the 50S ribosomal subunit (Thompson et al, 2002). With the exception of TYL, CMP, and ERY, the antibiotics used in this study are important in the treatment of infections caused by Gram-negative bacteria such as E. coli; however, CMP is often carried on a plasmid that also codes for resistance to multiple antibiotics (Jorgensen, 1978) that are effective on Gram-negative bacteria, and ERY is effective against some Gram-negative bacteria (Mao and Putterman, 1968). Guidelines from the CLSI (formerly the National Committee for Clinical Laboratory Standards) were used to prepare and dilute all antimicrobial agents except TYL, which was dissolved in methanol and adjusted to pH 7.9 using 0.1 mol L -1 phosphate buffer (Kaukas et al, 1988).…”

New translocation sequence mediating tetracycline resistance found in Escherichia coli pathogenic for piglets

“…This strain, 1324, contains several plasmids among which are two R plasmids as described in a previous publication (9). Genetic experiments reported there show that a deoxyribonucleic acid (DNA) segment coding for tetracycline resistance moves from one R plasmid to the other in the absence of the recA function.…”

“…Genetic experiments reported there show that a deoxyribonucleic acid (DNA) segment coding for tetracycline resistance moves from one R plasmid to the other in the absence of the recA function. The Media and antibiotics were those described by J0r-gensen (9). The conjugation technique was also described in that paper.…”