Antimicrobial Susceptibility and Cross-Resistance Patterns among Common Complicated Urinary Tract Infections in US Hospitals, 2013 to 2018

In the face of increasing rates of antimicrobial resistance in complicated urinary tract infections (cUTIs), clinicians need to understand cross-resistance patterns among commonly encountered pathogens. We performed a multicenter, retrospective cohort study in the Premier database of approximately 180 hospitals, from 2013 to 2018. Using an ICD-9/10-based algorithm, we identified all adult patients hospitalized with cUTIs and included those with a positive blood or urine culture. We examined the microbiology and susceptibilities to common cUTI antimicrobials (3rd-generation cephalosporin [C3], fluoroquinolones [FQ], trimethoprim-sulfamethoxazole (TMP/SMa fosfomycin [FFM], and nitrofurantoin (NFT]) singly and in groups of two. Among 28,057 organisms from 23,331 patients, the 3 most common pathogens were Escherichia coli (41.0%; C3(r), 15.1%), Klebsiella pneumoniae (12.1%; C3(r), 13.2%), and Pseudomonas aeruginosa (11.0%; C3(r), 12.0%). E. coli was most frequently resistant to FQ (43.5%) and least to NFT (6.7%). K. pneumoniae was most frequently resistant to NFT (60.8%) and least to FFM (0.1%). P. aeruginosa was most frequently resistant to FQ (34.4%) and least to TMP/SMZ (4.2%). Of the C3(r) E. coli isolates, 87.1% were also FQ(r), 63.7% were TMP/SMZ(r), and 13.3% were NFTr. C3(r) K. pneumoniae isolates had a 76.5% chance of being FQ(r), 78.1% were TMP/SMZ(r), and 77.6% were NFTr. C3(r) P. aeruginosa coexisted with FQ(r) in 47.3%, TMP/SMZ(r) in 18.9%, and NFTr in 28.7%. Among the most common pathogens isolated from hospitalized patients with cUTIs, the rates of single resistance to common treatments and of cross-resistance to these regimens are substantial. Knowing the patterns of crossresistance may help clinicians tailor empirical therapy more precisely.