Open AccessCharacterisation of drug resistance gene cassettes associated with class 1 integrons in clinical isolates of Escherichia coli from Taiwan, ROC
Author(s) -
Chih-Yuan Chang,
LinLi Chang,
YuHung Chang,
Tsong-Ming Lee,
Shui-Feng Chang
Publication year - 2000
Publication title -
journal of medical microbiology/journal of medical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 117
eISSN - 1473-5644
pISSN - 0022-2615
DOI - 10.1099/0022-1317-49-12-1097
Subject(s) - integron , biology , escherichia coli , gene , microbiology and biotechnology , plasmid , genetics , gene cassette , chloramphenicol , drug resistance , antibiotics
The presence of class 1 integrons in clinical isolates of Escherichia coli was detected by PCR. Of 104 E. coli isolates from Kaohsiung, 54 (52%) carried class 1 integrons, with inserted DNA regions of 1-3 kb. These integrons were located on plasmids, as demonstrated by Southern hybridisation. DNA sequencing was used to identify the genetic content of the integron-variable regions. Different class 1 integrons contained various numbers, kinds and combinations of gene cassettes within their variable regions. These gene cassettes included those encoding resistance to trimethoprim (dfrIa, dfrV, dfr12 and dfr17), aminoglycosides (aadA1a, aadA2, aadA4 and aadB), chloramphenicol (cmlA), erythromycin (ereA2) and beta-lactams (blaP1). An integron carrying three inserted cassettes - dfr12-orJF-aadA2 - was present in 33 (61%) of the 54 isolates with class 1 integrons. Gene cassettes encoding resistance were expressed phenotypically. The results indicate that class 1 integrons are widespread in clinical E. coli isolates in Taiwan. The types, combinations and frequency of the gene cassettes in integrons may reflect the specific selective pressures to which the isolates were exposed and could provide useful surveillance data for relation to antibiotic usage information.