In vitro and in vivo evaluation of cephalosporins for the treatment of Lyme disease

Abstract

Background: Lyme disease accounts for >90% of all vector-borne disease cases in the United States and affect ~300,000 persons annually in North America. Though traditional tetracycline antibiotic therapy is generally prescribed for Lyme disease, still 10%-20% of patients treated with current antibiotic therapy still show lingering symptoms.

Methods: In order to identify new drugs, we have evaluated four cephalosporins as a therapeutic alternative to commonly used antibiotics for the treatment of Lyme disease by using microdilution techniques like minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). We have determined the MIC and MBC of four drugs for three Borrelia burgdorferi s.s strains namely CA8, JLB31 and NP40. The binding studies were performed using in silico analysis.

Results: The MIC order of the four drugs tested is cefoxitin (1.25 µM/mL) > cefamandole (2.5 µM/mL), > cefuroxime (5 µM/mL) > cefapirin (10 µM/mL). Among the drugs that are tested in this study using in vivo C3H/HeN mouse model, cefoxitin effectively kills B. burgdorferi. The in silico analysis revealed that all four cephalosporins studied binds effectively to B. burgdorferi proteins, SecA subunit penicillin-binding protein (PBP) and Outer surface protein E (OspE).

Conclusion: Based on the data obtained, cefoxitin has shown high efficacy killing B. burgdorferi at concentration of 1.25 µM/mL. In addition to it, cefoxitin cleared B. burgdorferi infection in C3H/HeN mice model at 20 mg/kg.

Keywords: Borrelia burgdorferi; Lyme disease; antimicrobials; penicillin-binding proteins.

Figure 1

The efficacy of cephalosporins determined by BacTiter-Glo Assay. Notes: Effect of drugs on Borrelia cell viability was studied with drugs (cefoxitin, cefamandole, cefuroxime, and cefapirin) on CA8 strain. The control has no drug. The results represent mean ± SD.

Figure 2

Spatial arrangement of the in silico tested cephalosporins with secA translocase PBP of Borrelia burgdorferi: (A) cefamandole, (B) cefapirin, (C) cefoxitin, and (D) cefuroxime. Note: The amino acid sequence of secA-PBP (B. burgdorferi B31) was retrieved from the Uniprot KB (Gene BB_0718) with a GenBank gene accession number of AE000783 (translation AAC67056.2.). Abbreviation: PBP, penicillin-binding protein.