Molecular epidemiology of Escherichia coli producing CTX-M β-lactamases: the worldwide emergence of clone ST131 O25:H4

Since 2000, Escherichia coli producing CTX-M enzymes have emerged worldwide as important causes of community-onset urinary tract and bloodstream infections owing to extended-spectrum β-lactamase (ESBL)-producing bacteria. Molecular epidemiological studies suggested that the sudden worldwide increase of CTX-M-15-producing E. coli was mainly due to a single clone (ST131) and that foreign travel to high-risk areas, such as the Indian subcontinent, might in part play a role in the spread of this clone across different continents. Empirical antibiotic coverage for these resistant organisms should be considered in community patients presenting with sepsis involving the urinary tract, especially if the patient recently travelled to a high-risk area. If this emerging public health threat is ignored, it is possible that the medical community may be forced, in the near future, to use carbapenems as the first choice for the empirical treatment of serious infections associated with urinary tract infections originating from the community.