Emergence of fluoroquinolone‐resistant clonal group A: clonal analysis of Norwegian and Russian E. coli isolates

Abstract

We describe a study of urinary tract and intestinal isolates of Escherichia coli from Norway and Russia using automated ribotyping, single nucleotide polymorphism analysis for clonal group A (CgA) supplemented with phylogrouping, virulence gene profiling and resistance profiling. CgA comprised 19% of the Norwegian UTI isolates from 2001. Two highly multiresistant fluoroquinolone-resistant CgA isolates were found. Ribotypes clustered into four major and six minor groups (ribogroups). Fluoroquinolone-resistant isolates and phylogroups A and B1 were associated with ribogroup (R)A. Ribogroup (R)B predominated among Russian UTI isolates and was predominantly phylogroup A and depleted in P-fimbriae. Ribogroup (R)C predominated among Norwegian UTI isolates and was rich in virulence factors (S-fimbriae, haemagglutinin and haemolysin) and predominantly phylogroup B2 and D. Ribogroup (R)G was associated with CgA and predominantly phylogroup D. Ribogroups (R)D, (R)E and (R)F had too few members for statistical analysis. The correlation between ribotype and phylogenetic group was not as strong as reported in other studies.

High levels of multiresistance in quinolone resistant urinary tract isolates of Escherichia coli from Norway; a non clonal phenomen?

“…All CGA isolates were quinolone resistant and one third were ciprofloxacin resistant, confirming the emergence of fluoroquinolone resistance in CGA that we [20] and others [11] have previously observed. Although CGA is considered a multiresistant clone, CGA isolates in this material were not significantly more multiresistant than other quinolone resistant isolates (p > 0.5, z-test).…”

“…Our results suggest that multiresistance emerges early in the development of ciprofloxacin resistance and place constraints on several of the possible explanations for association between ciprofloxacin resistance and multiresistance. We also reinvestigate our earlier findings suggesting fluoroquinolone resistance and clonal spread and the emergence of fluoroquinolone resistance in clonal group A [20]. …”

“…These isolates were not clonally related. However, one isolate belonged to clonal group A and resembled two highly resistant CGA isolates previously isolated by us in 2003 [20]. …”

“…The reason for this association is not understood, but several possibilities may be considered. Ciprofloxacin-resistant isolates have been reported to show a high level of clonality [8,14] and resistance has emerged in the multiresistant uropathogenic clonal group A (CGA) [15-20], which suggests a contribution from the spread of multiresistant clones under selection pressure. The agricultural sector has also been suggested as a source of ciprofloxacin resistance [21], in which case multiresistance might arise at source, driven by the extensive use of antibiotic additives as growth stimulants in animal feed.…”

Escherichia coli clonal group A causing bacteraemia of urinary tract origin

“…CgA has a worldwide endemic distribution with a concentration in the western world [9]. However, the distribution of CgA in Europe has received little investigation [8–11]. CgA isolates cause extraintestinal infections and especially its distribution among uropathogenic E. coli (UPEC) has been investigated [5,6,8,10,12].…”