J Korean Soc Microbiol.  1997 Oct;32(5):553-568.

Transferable Trimethoprim Resistance in Urine Isolates of Escherichia coli

• Seol SY
• Cho DT
• Lee YC
• Kim JM
• Shin HS
• Chang HK
• Hyun HS

Abstract

One hundred and twenty-two strains of E. coli isolated from urinary tract infection were examined for antibiogram, transferability of trimethoprim (Tp) resistance, incompatibility with F group plasmid and southem hybridization with DHFR I, II, and III probe of Tp-resistant R plasmids. 1. Among 172 Gram negative bacilli isolated from urinary tract infection, 122 (70.9%) were E. coli and 75 strains of them were resistant to trimethoprim (Tp). Most of Tp-resistant isolates were also resistant to penicillins (ampicillin, carbenicillin, and ticarcillin), aminoglycosides (kanamycin and gentamicin), and sulfisoxazole but almost all strains were susceptible to cephalosporins. 2. Most of Tp-resistant strains and E. coli transconjugant derived from them showed multiple drug resistance and various antimicrobial resistance patterns. 3. Thirty-three Tp-resistant strains (45.2%) transferred 35 Tp-resistant plasmids to E. coli recipients but among them 6 transconjugants did not show retransfer of resistance and plasmid DNA were not detected in 2 transconjugants after resistance transfer. 4. Tp-resistant R plasmids ranged from 157 to 67 kb and 8 R plasmids were classified to incompatibilty group IncFI or IncFII ranging from 120 to 83 kb. Three and two R plasmids belonged to IncFII showed similar molecular weight, resistance pattern, and reaction site by southern hybridization with DHFR I probe. Twenty-five plasmids specifically responded on various EcoRI endonuclease fragments to DHFR I probe but not to DHFR II or DHFR III probe. These findings suggest that most of Tp- resistant R plasmids from urine isolates of E. coli were derived from various sources but some plasmids including IncFII R plasmids were probably originated from same or similar sources.

MeSH Terms

Aminoglycosides
Carbenicillin
Cephalosporins
Deoxyribonuclease EcoRI
DNA
Drug Resistance, Multiple
Escherichia coli*
Escherichia*
Microbial Sensitivity Tests
Molecular Weight
Penicillins
Plasmids
R Factors
Sulfisoxazole
Trimethoprim Resistance*
Trimethoprim*
Urinary Tract Infections
Aminoglycosides
Carbenicillin
Cephalosporins
DNA
Deoxyribonuclease EcoRI
Penicillins
Sulfisoxazole
Trimethoprim