Transfer of antibiotic resistance plasmids in pure and activated sludge cultures in the presence of environmentally representative micro-contaminant concentrations.
The presence of antibiotics in the natural environment has been a growing issue. This presence could also account for the influence that affects microorganisms in such a way that they develop resistance against these antibiotics. The aim of this study was to evaluate whether the antibiotic resistant gene (ARG) plasmid transfer can be facilitated by the impact of 1) environmentally representative micro-contaminant concentrations in ppb (part per billion) levels and 2) donor-recipient microbial complexity (pure vs. mixed). For this purpose, the multidrug resistant plasmid, pB10, and Escherichia coli DH5α were used as a model plasmid and a model donor, respectively. Based on conjugation experiments with pure (Pseudomonas aeruginosa PAKexoT) and mixed (activated sludge) cultures as recipients, increased relative plasmid transfer frequencies were observed at ppb (μg/L) levels of tetracycline and sulfamethoxazole micro-contaminant exposure. When sludge, a more complex community, was used as a recipient, the increases of the plasmid transfer rate were always statistically significant but not always in P. aeruginosa. The low concentration (10 ppb) of tetracycline exposure led to the pB10 transfer to enteric bacteria, which are clinically important pathogens.
Department of Environmental Engineering, Korea University, Sejong 339-700, Republic of Korea. Electronic address: ub1905ub@korea.ac.kr.
Sungpyo
S
Kim
Zuwhan
Z
Yun
Un-Hwan
UH
Ha
Seokho
S
Lee
Hongkeun
H
Park
Eilhann E
EE
Kwon
Yunchul
Y
Cho
Sungwook
S
Choung
Junsik
J
Oh
Carl Angelo
CA
Medriano
Kartik
K
Chandran
D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000032:analysis*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli; D022761:Gene Transfer, Horizontal / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D011550:Pseudomonas aeruginosa; D012722:Sewage / Q000382:microbiology*; D013420:Sulfamethoxazole; D013752:Tetracycline
D000900:Anti-Bacterial Agents; D012722:Sewage; D013752:Tetracycline; D013420:Sulfamethoxazole
Activated sludge; Antibiotic resistance gene; Conjugation; Sulfamethoxazole; Tetracycline