Real-World Effectiveness of Intravenous and Oral Antibiotic Stepdown Strategies for Gram-Negative Complicated Urinary Tract Infection With Bacteremia

Background

Robust data are lacking regarding the optimal route, duration, and antibiotic choice for gram-negative bloodstream infection from a complicated urinary tract infection source (GN-BSI/cUTI).

Methods

In this multicenter observational cohort study, we simulated a 4-arm registry trial using a causal inference method to compare effectiveness of the following regimens for GN-BSI/cUTI: complete course of an intravenous β-lactam (IVBL) or oral stepdown therapy within 7 days using fluoroquinolones (FQs), trimethoprim-sulfamethoxazole (TMP-SMX), or high-bioavailability β-lactams (HBBLs). Adults treated between January 2016 and December 2022 for Escherichia coli or Klebsiella species GN-BSI/cUTI were included. Propensity weighting was used to balance characteristics between groups. The 60-day recurrence was compared using a multinomial Cox proportional hazards model with probability of treatment weighting.

Results

Of 2571 patients screened, 759 (30%) were included. Characteristics were similar between groups. Compared with IVBLs, we did not observe a difference in effectiveness for FQs (adjusted hazard ratio, 1.09 [95% confidence interval, .49-2.43]) or TMP-SMX (1.44 [.54-3.87]), and the effectiveness of TMP-SMX/FQ appeared to be optimal at durations of >10 days. HBBLs were associated with nearly 4-fold higher risk of recurrence (adjusted hazard ratio, 3.83 [95% confidence interval, 1.76-8.33]), which was not mitigated by longer treatment durations. Most HBBLs (67%) were not optimally dosed for bacteremia. Results were robust to multiple sensitivity analyses.

Conclusions

These real-world data suggest that oral stepdown therapy with FQs or TMP-SMX have similar effectiveness as IVBLs. HBBLs were associated with higher recurrence rates, but dosing was suboptimal. Further data are needed to define optimal dosing and duration to mitigate treatment failures.

Oral β-Lactams, Fluoroquinolones, or Trimethoprim-Sulfamethoxazole for Definitive Treatment of Uncomplicated Escherichia coli or Klebsiella Species Bacteremia From a Urinary Tract Source

Background

Fluoroquinolones (FQs) are effective for oral step-down therapy for gram-negative bloodstream infections but are associated with unfavorable toxic effects. Robust data are lacking for trimethoprim-sulfamethoxazole (TMP-SMX) and high-bioavailability β-lactams (HBBLs).

Methods

In this multicenter observational cohort study, we simulated a 3-arm registry trial using causal inference methods to compare the effectiveness of FQs, TMP-SMX, or HBBLs for gram-negative bloodstream infections oral step-down therapy. The study included adults treated between January 2016 and December 2022 for uncomplicated Escherichia coli or Klebsiella species bacteremia of urinary tract origin who were who were transitioned to an oral regimen after ≤4 days of effective intravenous antibiotics. Propensity weighting was used to balance characteristics between groups. 60-day recurrence was compared using a multinomial Cox proportional hazards model with probability of treatment weighting.

Results

Of 2571 patients screened, 648 (25%) were included. Their median age (interquartile range) was 67 (45-78) years, and only 103 (16%) were male. Characteristics were well balanced between groups. Compared with FQs, TMP-SMX had similar effectiveness (adjusted hazard ratio, 0.91 [95% confidence interval, .30-2.78]), and HBBLs had a higher risk of recurrence (2.19 [.95-5.01]), although this difference was not statistically significant. Most HBBLs (70%) were not optimally dosed for bacteremia. A total antibiotic duration ≤8 days was associated with a higher recurrence rate in select patients with risk factors for failure.

Conclusions

FQs and TMP-SMX had similar effectiveness in this real-world data set. HBBLs were associated with higher recurrence rates but suboptimal dosing may have contributed. Further studies are needed to define optimal BL dosing and duration to mitigate treatment failures.

Outcomes of patients with bacteriuria/pyuria of clinically undetermined significance (BPCUS) treated with antibiotics in 23 community hospital emergency departments

The optimal management of bacteriuria/pyuria of clinically undetermined significance (BPCUS) is unknown. Among 220 emergency department patients prescribed antibiotics for BPCUS, we found frequent readmissions, which were mitigated by outpatient follow-up visits. Observation and follow-up for an unknown diagnosis should be emphasized over antibiotics due to high likelihood of readmissions.

Assessment of invitrosynergy of daptomycin or vancomycin plus ceftaroline for daptomycin non-susceptible Staphylococcus aureus

The combination of vancomycin or daptomycin plus ceftaroline has showed synergistic results in vitro. This study aimed to investigate in vitro synergy of vancomycin or daptomycin plus ceftaroline for seven patients with daptomycin non-susceptible Staphylococcus aureus (SA) bacteremia Thirteen isolates from seven patients were evaluated: two methicillin-susceptible and five methicillin-resistant SA infections. All patients were treated with daptomycin and became non-susceptible (minimum inhibitory concentration (MIC) >1 μg/mL) with therapy or had resistant strains initially. Time kill experiments were completed with 0.25 × MIC, 0.5 × MIC, and 0.75 × MIC concentrations. No synergy was seen at 0.25 × MIC. Synergy was observed for 4 isolates with vancomycin plus ceftaroline and with daptomycin plus ceftaroline for 2 isolates at 0.5 × MIC. These results are in accordance with literature that supports synergistic combinations of daptomycin or vancomycin with ceftaroline for SA bacteremia. Daptomycin non-susceptible SA bacteremia presents a treatment challenge.

Assessment of the AUTOGRP patient classification system

This study was conducted to assess the adaptability of the AUTOGRP Patient Classification System (APCS) to the patient population of western Pennsylvania. The APCS consists of a fixed sex of 383 patient categories, each of which is purported to contain similar patients with respect to resource consumption as measured by length of stay. The assessment of the APCS examines both the reproducibility of the classification using western Pennsylvania patient date and the homogeneity of the resultant categories. The results indicate that the APCS categories examined were not statistically optimal using western Pennsylvania data, and that individual diagnostic-related groups within the APCS do not contain similar patients with respect to resource consumption and with respect to other patient and hospital characteristics.