Promising In Vitro Activity of Tebipenem Against Enterobacterales in Outpatient Clinics and Nursing Homes

Research published in the International Journal of Antimicrobial Agents found that tebipenem shows outstanding in vitro activity against Enterobacterales isolated from patients in outpatient settings, such as urology clinics and nursing homes.  

The study examined the effectiveness of tebipenem as a treatment option for various infections, considering its safety profile of the β-lactam antimicrobial class and convenient oral dosage. The in vitro evaluation focused on testing tebipenem against clinical Enterobacterales samples obtained from outpatient and community settings of nursing homes and urology clinics 

In 2022, 11 US medical centers across different regions contributed 618 Enterobacterales isolates collected from outpatient centers affiliated with these centers. These isolates underwent susceptibility testing for tebipenem and other comparator agents using broth microdilution. Isolates showing extended-spectrum-β-lactamase (ESBL)-like characteristics were identified through phenotypic methods, while multidrug-resistant isolates were defined as non-susceptible to at least one agent in three or more antimicrobial classes. Additionally, a subset of isolates underwent genotypic testing using CarbaR. 

Patients seen primarily in urology/nephrology (24%), nursing home/long-term care (21%), and ambulatory/primary care (21%) clinics were tested for isolates (59% Escherichia coli). The proportion of comparator agent susceptibility rates against all isolates were: 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%).  

Researchers found that 90.3% (558/619) of isolates were inhibited when the tebipenem MIC was at or below 0.125 mg/L (specifically, MIC50/90 values were 0.016/0.125 mg/L), including 85.7% of isolates with the ESBL-phenotype (n=161; MIC50/90, 0.03/0.25 mg/L), 86.3% of isolates resistant to levofloxacin and sulfamethoxazole/trimethoprim (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). Among the ESBL-phenotype isolates, tebipenem MIC values of ≥0.5 mg/L were associated with the presence of carbapenemase genes in 2 isolates. 

“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,” said researchers. 

Reference  

Asempa T E, Bobenchik A M, Bourassa L, et al. Antimicrobial activity of tebipenem and comparators against enterobacterales from diverse outpatient centers and nursing homes in the United States. Int Journ of Antimicrobial Agents. 2023;61(3):106733. doi:10.1016/j.ijantimicag.2023.106733.