Premium
Acetylation of fluoroquinolone antimicrobial agents by an Escherichia coli strain isolated from a municipal wastewater treatment plant
Author(s) -
Jung C.M.,
Heinze T.M.,
Strakosha R.,
Elkins C.A.,
Sutherland J.B.
Publication year - 2009
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2008.04026.x
Subject(s) - antimicrobial , escherichia coli , microbiology and biotechnology , strain (injury) , wastewater , bacteria , acetylation , biology , chemistry , environmental engineering , environmental science , biochemistry , gene , genetics , anatomy
Aims: To isolate environmental bacteria capable of transforming fluoroquinolones to inactive molecules. Methods and Results: Bacteria were isolated from the aerobic liquor of a wastewater treatment plant on a medium containing norfloxacin (100 mg l −1 ). Twenty‐two isolates were highly resistant (minimal inhibitory concentration: 6·25−200 μg ml −1 ) to five fluoroquinolones and six of them were positive by PCR amplification for the aminoglycoside resistance gene aac(6′)‐Ib. Of these, only Escherichia coli strain LR09 had the ciprofloxacin‐acetylating variant gene aac(6′)‐Ib‐cr ; HPLC and mass spectrometry showed that this strain transformed both ciprofloxacin and norfloxacin by N ‐acetylation. This bacterium also had mutations in the quinolone‐resistance determining regions of the gyrA and parC genes. Conclusions: An E. coli isolate from wastewater, which possessed at least two distinct fluoroquinolone resistance mechanisms, inactivated ciprofloxacin and norfloxacin by N ‐acetylation. Significance and Impact of the Study: This is the first report of N ‐acetylation of fluoroquinolones by an aac(6′)‐Ib‐cr ‐containing bacterium from an environmental source.