Women with uncomplicated urinary tract infection (uUTI) and antimicrobial-resistant isolates were found to be at significantly increased risk for progression to complicated UTI (cUTI) compared with those with susceptible isolates, according to research presented at IDWeek, held virtually from September 29 to October 2, 2021.

In this retrospective cohort study, investigators obtained data from electronic health records on women (N=2565) 12 years and older (mean, 43.5 years) with incident uUTI (diagnosis code or urine culture) who were given oral antibiotic (AB) therapy within 5 days prior to or after their initial diagnosis and 1 or more AB susceptibility tests.

The primary outcome was the probability of progression to cUTI, defined as new fever, nausea, or vomiting in addition to uUTI symptoms, or treatment with intravenous AB between 3 and 28 days after the index uUTI. Progression probability was determined by comparing patients with nonsusceptible (n=1535) vs those with susceptible (n=1030) isolates, with subsequent propensity score matching in a 1:1 fashion. Patients were retained for analysis if they had a nonzero predicted probability of uUTI progression; the case and control groups were analyzed only if there were patients in the mirror group with similar probability propensity scores.

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After propensity score matching, 10.7% of patients with nonsusceptible isolates and 4.9% with susceptible isolates were found to be at increased risk for progression to cUTI (odds ratio, 2.35; P <.001). Among patients with nonsusceptible isolates, sensitivity analyses also showed an increased risk for progression to cUTI (P ≤.009), excluding those who received fluoroquinolones only.

“This finding highlights the need for greater understanding of antimicrobial resistance and has implications for the clinical management of uUTI,” the investigators concluded.

Disclosure: Some author(s) declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of disclosures.


Shafrin J, Marijam A, Joshi AV, et al. Progression of an uncomplicated urinary tract infection among female patients with susceptible and non-susceptible urine isolates: findings from an integrated delivery network. Presented at: IDWeek; September 29 to October 3, 2021. Poster 194.

This article originally appeared on Infectious Disease Advisor