Triclosan susceptibility and co-metabolism--a comparison for three aerobic pollutant-degrading bacteria.
The antimicrobial agent triclosan is an emerging and persistent environmental pollutant. This study evaluated the susceptibility and biodegradation potential of triclosan by three bacterial strains (Sphingomonas wittichii RW1, Burkholderia xenovorans LB400 and Sphingomonas sp. PH-07) that are able to degrade aromatic pollutants (dibenzofuran, biphenyl and diphenyl ether, respectively) with structural similarities to triclosan. These strains showed less susceptibility to triclosan when grown in complex and mineral salts media. Biodegradation experiments revealed that only strain PH-07 was able to catabolize triclosan to intermediates that included hydroxylated compounds (monohydroxy-triclosan, and dihydroxy-triclosan) and the ether bond cleavage products (4-chlorophenol and 2,4-dichlorophenol), indicating that the initial dihydroxylation occurred on both aromatic rings of triclosan. Additional growth inhibition tests demonstrated that the main intermediate, 2,4-dichlorophenol, was less toxic to strain PH-07 than was triclosan. Our results indicate that ether bond cleavage might be the primary mechanism of avoiding triclosan toxicity by this strain.
School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
Young-Mo
YM
Kim
Kumarasamy
K
Murugesan
Stefan
S
Schmidt
Varima
V
Bokare
Jong-Rok
JR
Jeon
Eun-Ju
EJ
Kim
Yoon-Seok
YS
Chang
D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D001420:Bacteria, Aerobic / Q000145:classification* / Q000187:drug effects* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002470:Cell Survival / Q000187:drug effects; D006801:Humans; D008660:Metabolism; D013045:Species Specificity; D014260:Triclosan / Q000378:metabolism* / Q000494:pharmacology*
D000891:Anti-Infective Agents, Local; D014260:Triclosan