ABSTRACT
INTRODUCTION: Tebipenem is a potential option for the treatment of a range of infections because of its oral dosing coupled with the safety profile of the ß-lactam antimicrobial class. OBJECTIVES: To evaluate tebipenem in vitro activity against a challenge set of clinical Enterobacterales collected from outpatient and community settings. METHODS: 618 Enterobacterales isolates were submitted by 11 geographically dispersed U.S medical centers that processed cultures from affiliated outpatient centers in 2022. Susceptibility tests for tebipenem and comparator agents were performed by broth microdilution. Extended-spectrum-ß-lactamase (ESBL)-like isolates were identified phenotypically. Multidrug-resistant isolates were non-susceptible to ≥1 agent in ≥3 antimicrobial classes. Genotypic testing (CarbaR) was conducted on select isolates. RESULTS: Isolates (59% Escherichia coli) were recovered from patients seen predominantly in urology/nephrology (24%), nursing home/long-term care (21%), and ambulatory/primary care (21%) clinics. Comparator agent susceptibility rates against all isolates were as follows: levofloxacin (67.5%), amoxicillin/clavulanate (73.6%), cefixime (70.4%), cefpodoxime (70%), cephalexin (61.7%), ceftriaxone (74.4%), cefazolin (63.8%), ertapenem (97.6%), meropenem (99.7%), nitrofurantoin (64.9%), and sulfamethoxazole/trimethoprim (70.9%). Overall, 90.3% (558/619) of isolates were inhibited at a tebipenem MIC of ≤0.125 mg/L (MIC50/90, 0.016/0.125 mg/L), including 85.7% inhibition of ESBL-phenotype isolates (n=161; MIC50/90, 0.03/0.25 mg/L), 86.3% of levofloxacin and sulfamethoxazole/trimethoprim co-resistant isolates (n=95; MIC50/90, 0.016/0.25 mg/L) and 84.3% of multidrug-resistant isolates (n = 172; MIC50/90, 0.03/0.25 mg/L). Carbapenemase genes were observed in 2 ESBL-phenotype isolates with a tebipenem MIC of ≥0.5 mg/L. CONCLUSION: Relative to common oral comparators, these data demonstrate excellent tebipenem in vitro activity against Enterobacterales isolated from patients receiving care in outpatient settings, including urology clinics and nursing homes.
