The repurposing of Tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively drug resistant Shigella spp

Antibacterial Prodrugs to Overcome Bacterial Antimicrobial Resistance

Antimicrobial resistance (AMR) is an increasingly concerning phenomenon that requires urgent attention because it poses a threat to human and animal health. Bacteria undergo continuous evolution, acquiring novel resistance mechanisms in addition to their intrinsic ones. Multidrug-resistant and extensively drug-resistant bacterial strains are rapidly emerging, and it is expected that bacterial AMR will claim the lives of 10 million people annually by 2050. Consequently, the urgent need for the development of new therapeutic agents with new modes of action is evident. The antibacterial prodrug approach, a strategy that includes drug repurposing and derivatization, integration of nanotechnology, and exploration of natural products, is highlighted in this review. Thus, this publication aims at compiling the most pertinent research in the field, spanning from 2021 to 2023, offering the reader a comprehensive insight into the AMR phenomenon and new strategies to overcome it.

Bioequivalence Study of Tebipenem Pivoxil in Healthy Chinese Adults

BACKGROUND AND OBJECTIVE

Tebipenem pivoxil (TP) is a carbapenem and is applied against pneumonia, otitis media, and sinusitis. This study compared the pharmacokinetics (PK) and safety of a test (T) preparation and reference (R) preparation of TP in healthy Chinese adults.

METHODS

This study was a single-center, randomized, open, single-dose (fasting/postprandial) oral administration, two-agent, two-sequence, two-cycle, crossover bioequivalence trial. A total of 60 participants were enrolled (24 fasting and 36 postprandial). All participants were randomly assigned to the TR sequence and RT sequence. Subsequently, they switched T sequences or R sequences 7 days later. PK blood samples were collected according to the protocol, plasma TP concentration was determined by liquid chromatography-mass spectrometry, main PK parameters were calculated based on a non-compartment model, and adverse events were recorded during the test.

RESULTS

In the feeding arm, the geometric mean ratio of maximum concentration (Cmax) was 89.84% (90% confidence interval 84.33-95.70), the geometric mean ratio of area under the plasma concentration-time curve from time 0 to last time of quantifiable concentration (AUC0-t) was 86.80% (83.62-90.10), and the geometric mean ratio of area under the plasma concentration-time curve from time 0 to infinity time of quantifiable concentration (AUC0-∞) was 86.90% (83.73-90.20), which were within the acceptable range of bioequivalence (80-125%). In the fasting arm, the geometric mean ratio of Cmax was 96.07% (89.62-102.99), the geometric mean ratio of AUC0-t was 93.09% (90.47-95.78), and the geometric mean ratio of AUC0-∞ was 93.09% (90.48-95.77), which was within the acceptable range of bioequivalence (80-125%). Hence, the T preparation and R preparation of TP had bioequivalence in the fasting arm and feeding arm of the clinical trial. In addition, all adverse events were mild, and no severe adverse events were noted.

CONCLUSION

Preparations T and R of TP were bioequivalent in the fasting and postprandial groups in clinical trials, and TP was safe.

Activity of Oral Tebipenem-Avibactam in a Mouse Model of Mycobacterium abscessus Lung Infection

The combination of the β-lactam tebipenem and the β-lactamase inhibitor avibactam shows potent bactericidal activity against Mycobacterium abscessus in vitro. Here, we report that the combination of the respective oral prodrugs tebipenem-pivoxil and avibactam ARX-1796 showed efficacy in a mouse model of M. abscessus lung infection. The results suggest that tebipenem-avibactam presents an attractive oral drug candidate pair for the treatment of M. abscessus pulmonary disease and could inform the design of clinical trials.

Dissemination of Multiple Drug-Resistant Shigella flexneri 2a Isolates Among Pediatric Outpatients in Urumqi, China

Multiple drug-resistant (MDR) Shigella isolates have been reported worldwide. Between May 2017 and September 2018, 55 Shigella flexneri 2a isolates were collected from 3322 stool samples of 0-10-year-old outpatients with diarrhea at the Children's Hospital of Urumqi, China. All isolates were characterized using serotyping, antimicrobial susceptibility testing, and whole-genome sequencing. A total of 54 of 55 (98.2%) isolates exhibited MDR phenotypes and had accumulated multiple resistance determinants, particularly of fluoroquinolones and cephalosporins preferred for shigellosis treatment: point mutations in quinolone resistance-determining regions (QRDRs) of topoisomerases (GyrA (S83L, D87N) and ParC (S80I) [n = 9]; GyrA (S83L) and ParC (S80I) [n = 45]) and acquisition of qnrS1 (n = 3) and bla_CTX-M (n = 8). Over 70% of isolates acquired two point mutations of GyrA (S83L) and ParC (S80I) in QRDRs and 11 highly resistant isolates accumulated three point mutations in QRDRs or acquired qnrS1. Four S. flexneri 2a isolates from three single-nucleotide polymorphism clusters exhibited coresistance to ciprofloxacin, cefotaxime, or azithromycin (AZM), which are used as first- and second-line shigellosis treatment antimicrobials in clinics. Our data indicated that fluoroquinolones should be terminated in shigellosis treatment for outpatients in Urumqi. The transferable antimicrobial resistance determinants have been identified for third-generation cephalosporins and AZM. Novel strategies are urgently required for developing empirical medication to reduce the antimicrobial selective pressure and prevent dissemination of MDR S. flexneri 2a isolates.