Population structure, virulence potential and antibiotic susceptibility of uropathogenic Escherichia coli from Northwest England.
OBJECTIVE
Multilocus sequence typing (MLST) has been used to characterize diverse pathogens, including uropathogenic Escherichia coli (UPEC). There has been significant interest in the contribution of the O25b:H4-ST131 lineage to UPEC disease, as these isolates are often highly virulent and exhibit multidrug resistance. To reveal the wider impact of sequence type (ST) 131, we have examined its contribution to the overall population structure of UPEC isolates that were not selected on the basis of virulence or antibiotic resistance.


METHODS
Three hundred UPEC isolates were recovered from community and hospital urine samples examined by clinical microbiology laboratories in the Northwest region of England in June 2007 and June 2009. They were characterized by susceptibility profiling, MLST and virulence gene PCR. PFGE was used to examine isolates from key clones.


RESULTS
The most common lineage was ST73 (16.6%) followed by ST131 (13.3%), ST69 (9%), ST95 (6.3%), ST10 (4.3%) and ST127 (3.6%). ST131 isolates were significantly more likely to exhibit high levels of antibiotic resistance (35% being CTX-M-15 PCR positive) and those of ST127 were the most widely susceptible but carried the highest number of virulence genes. Only when the CTX-M-15-O25b-positive strains were examined was a high level of virulence observed for ST131 isolates. PFGE indicated ongoing local evolution in ST131.


CONCLUSIONS
ST131 isolates are well established in the wider UPEC population. This clone is still evolving and we further support suggestions that it represents a real threat to health. We suggest that ST127 is a recently emerged, community-associated, virulent clone that warrants further study.
Microbiology and Virology Unit,  School of Translational Medicine, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9WL,  UK.
Tarek M
TM
Gibreel
Andrew R
AR
Dodgson
John
J
Cheesbrough
Andrew J
AJ
Fox
Frederick J
FJ
Bolton
Mathew
M
Upton
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D044822:Biodiversity; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D004739:England; D004927:Escherichia coli Infections / Q000382:microbiology*; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D010641:Phenotype; D014556:Urine / Q000382:microbiology; D056689:Uropathogenic Escherichia coli / Q000145:classification* / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence; D055815:Young Adult
D000900:Anti-Bacterial Agents