Trimethoprim-resistant Shigella and enterotoxigenic escherichia coli strains in children in Thailand

Arunsri Chatkaeomorakot, Peter Echeverria, David N. Taylor, Jitvimol Seriwatana, Udom Leksomboon

Research output: Contribution to journalArticlepeer-review

Abstract

The percentage of Shigella and enterotoxigenic Escherichia coli (ETEC) strains resistant to trimethoprim (TMP)-sulfamethoxazole isolated from children with diarrhea at the outpatient department of the Children’s Hospital in Bangkok increased from 3 and 0%, respectively, in 1982 to 29% and 25% in 1986. One hundred thirty-nine Shigella and 22 ETEC strains resistant to >1024 μg/ml of trimethoprim (TMPr) isolated from children with diarrhea in Bangkok in 1984 and 1985 were analyzed for the presence of type I, II and III plasmid-specific dihydrofolate reductase (DHFR) genes. Thirty-two percent (45 of 139) of TMPR Shigella had genes encoding type II and 9% (13 of 139) had genes encoding type I DHFR genes. Fifty percent (11 of 22) of TMPR ETEC had type II and 14% (3 of 22) had type I DHFR genes. Plasmids encoding DHFR were identified by the Southern technique in 24% (14 of 58) of Shigella and 1 of 14 ETEC that contained genes encoding DHFR. Plasmids coding for type II DHFR were transferred to E. coli K12 by conjugation from 13 of 14 Shigella and a plasmid coding for type I DHFR was transferred from the single ETEC containing a plasmid coding for type I DHFR. Genes coding for DHFR were presumably situated on the chromosome in 76% (44 of 58) of Shigella and 93% (13 of 14) of ETEC that contained genes encoding DHFR. Since 58% (81 of 139) of TMPR Shigella and 36% (8 of 22) of TMPr ETEC strains examined did nnt contain fffvnfis «ncnHintr t.vnp T. TT nr TTT DHFR, high level TMP resistance was presumably caused by other types of DHFR genes. Additional studies should be performed to characterize mechanisms of TMP resistance in Shigella and ETEC in Thailand. TMP-sulfamethoxazole may no longer be efficacious in the treatment of Shigella and ETEC infections in Thailand.

Original languageEnglish (US)
Pages (from-to)735-739
Number of pages5
JournalPediatric Infectious Disease Journal
Volume6
Issue number8
StatePublished - Aug 1987

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Microbiology (medical)
  • Infectious Diseases

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