Colonization or infection of the urinary tract: do we pay attention?

I sincerely congratulate the authors of the recent report on carbapenem-resistant Klebsiella pneumoniae infection for their restraint in ascribing to carbapenem-resistant K. pneumoniae such properties as increased virulence or attributable mortality. They elegantly and correctly avoided a common temptation to perform multivariate analysis using their large database (eg, by comparing carbapenem-resistant K. pneumoniae isolates with carbapenem-susceptible K. pneumoniae isolates as a potential predictor of mortality). In conclusion, Oscar's behavior is most probably only associated with mortality—he is not necessarily a more virulent cat.