Atypical class 1 integron coexists with class 1 and class 2 integrons in multi-drug resistant Shigella flexneri isolates from China.
The antimicrobial resistance and the character of integrons were determined in 58 Shigella flexneri strains isolated from China. All isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). No intI3 was detected. The typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient E. coli DH5α. The gene cassettes of typical class 1 integrons dfrA17-aadA5 and dfrA12-orfF-aadA2 were detected in 54 strains (93.1%) and 1 strain, respectively. Atypical class 1 integrons located on the chromosome with gene cassettes bla (oxa-30)-aadA1 were detected in 55 isolates (94.8%). All the intI2 positive isolates carried gene cassettes dfrA1-sat1-aadA1. To our knowledge, this is the first report that atypical and typical class 1 integrons coexisted with class 2 integron in multi-drug resistant S. flexneri strains.
Department of Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, People's Republic of China.
Jing Yuan
JY
Zhu
Guang Cai
GC
Duan
Hai Yan
HY
Yang
Qing Tang
QT
Fan
Yuan Lin
YL
Xi
D002681:China; D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial; D004405:Dysentery, Bacillary / Q000382:microbiology*; D005798:Genes, Bacterial; D006801:Humans; D032023:Integrons; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D012763:Shigella flexneri / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
D004269:DNA, Bacterial