Class 1 and 2 integrons, sul resistance genes and antibiotic resistance in Escherichia coli isolated from Dongjiang River, South China.
Antibiotic susceptibility, detection of sul gene types and presence of class 1, 2 and 3 integrons and gene cassettes using PCR assays were investigated in 3456 Escherichia coli isolates obtained from 38 sampling sites of the Dongjiang River catchment in the dry and wet seasons. 89.1% of the isolates were resistant and 87.5% showed resistance to at least three antibiotics. sul2 was detected most frequently in 89.2% of 1403 SXT-resistant isolates. The presence of integrons (class 1 and 2) was frequently observed (82.3%) while no class 3 integron was found. In these integrons, 21 resistance genes of 14 gene cassette arrays and 10 different families of resistance genes were identified. Three gene cassette arrays, aac(6')-Ib-cr-aar-3-dfrA27-aadA16, aacA4-catB3-dfrA1 and aadA2-lnuF, were detected for the first time in surface water. The results showed that bacterial resistance in the catchment was seriously influenced by human activities, especially discharge of wastewater.
State Key Laboratory of Organic Geochemistry, CAS Centre for Pearl River Delta Environmental Pollution and Control Research, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
Hao-Chang
HC
Su
Guang-Guo
GG
Ying
Ran
R
Tao
Rui-Quan
RQ
Zhang
Jian-Liang
JL
Zhao
You-Sheng
YS
Liu
D000900:Anti-Bacterial Agents; D002681:China; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D006802:Human Activities; D006801:Humans; D032023:Integrons; D008826:Microbial Sensitivity Tests; D045483:Rivers / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C091882:Sul1 protein, E coli