Inhibition of resistance plasmid transfer in Escherichia coli by ionophores, chlortetracycline, bacitracin, and ionophore/antimicrobial combinations.
Avian Dis
; 48(2): 317-23, 2004.
Article
em En
| MEDLINE
| ID: mdl-15283418
ABSTRACT
Medicinal feed additives bacitracin, chlortetracycline (CTC), laidlomycin, lasalocid, and salinomycin inhibited the transfer of multiresistance-conferring plasmid pBR325 (Tet(r) Amp(r) Cp(r), 6.0 kb) into selected gram-negative strains with the use of an in vitro model. High concentrations of ampicillin-sensitive competence-pretreated Escherichia coli HB 101 cells were exposed to 10% (v/v) of 110 dimethyl sulfoxide/agent water containing test mixtures for 0.5 hr prior to plasmid addition and transforming conditions. Transformation was inhibited for all antimicrobials and showed a positive association wich higher concentration. Additional testing of ionophore compounds separately and in combination with bacitracin, chlortetracycline, lincomycin, roxarsone, tylosin, and virginiamycin at representative feed concentrations demonstrated 80.6% to >99.9% inhibition (P < 0.001) of resistance transfer. Bacitracin alone inhibited transformation within the range of 50-500 ppm. No increase in resistance transfer was observed when poultry-derived and reference gram-negative isolates having low or no transformation efficiency were additionally tested. The results suggest that these compounds, at relevant concentrations used in animal feed, may interfere with cell envelope-associated DNA uptake channels or other transformation competence mechanisms. Through these mechanisms, ionophores and cell membrane-interactive feed agents such as CTC and bacitracin may act to inhibit resistance transfer mechanisms within poultry and livestock.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bacitracina
/
Transformação Bacteriana
/
Monensin
/
Clortetraciclina
/
Farmacorresistência Bacteriana
/
Quimioterapia Combinada
/
Escherichia coli
/
Ionóforos
Idioma:
En
Revista:
Avian Dis
Ano de publicação:
2004
Tipo de documento:
Article
País de afiliação:
Estados Unidos