Synthesis of the cyanobacterial halometabolite Chlorosphaerolactylate B and demonstration of its antimicrobial effect and .

Chlorosphaerolactylate B, a newly discovered antimicrobial halometabolite from the cyanobacterium sp. LEGE 00249 has been synthesized in three steps by using 12-bromododecanoic acid as starting material. A total of 0.5 g was produced for and antimicrobial efficacy testing. , the minimal inhibitory concentration (MIC) was estimated to be 256 mg/L for , while the minimal biofilm inhibitory concentration (MBIC) was estimated to be 74 mg/L. The study utilized a porcine model of implant-associated osteomyelitis. In total, 12 female pigs were allocated into 3 groups based on inoculum ( = 4 in each group). An implant cavity (IC) was drilled in the right tibia and followed by inoculation and insertion of a steel implant. All pigs were inoculated with 10 μL containing either: 11.79 mg synthetic Chlorosphaerolactylate B + 10 CFU of (Group A), 10 CFU of (Group B), or pure saline (Group C), respectively. Pigs were euthanized five days after inoculation. All Group B animals showed macroscopic and microscopic signs of bone infection and both tissue and implant harbored bacteria (mean CFU on implants = 1.9 × 10). In contrast, could not be isolated from animals inoculated with saline. In Group A, two animals had a low number of (CFU = 6.7 × 10 and 3.8 × 10, respectively) on the implants, otherwise all Group A animals were similar to Group C animals. In conclusion, synthetic Chlorosphaerolactylate B holds potential to be a novel antimicrobial and antibiofilm compound.