A new way of developing antibiotics using uncultivable soil bacterium is sparking interest with its potential to tackle an emerging public health problem posed by the rise of antibiotic resistance.
A novel antibiotic, called teixobactin, produced from bacteria in live dirt to treat mice infected with S. aureus or Streptococcus pneumonia reduced infection without adverse side effects, and, importantly, appears not to be susceptible to resistant bacteria.
“The antibiotic seems to work against many Gram-positive bacteria including those resistant to antibiotics in current use,” said Gerry Wright, PhD, who is with the department of biochemistry and biomedical sciences at McMaster University in Hamilton, Ontario, Canada, who wrote a commentary that accompanied the study (Nature 2015;517:442-444).
In the study, the researchers used a new technique to cultivate rare taxa that included cultivation in situ. Using a multichannel miniaturized device they developed called the iChip, the investigators cultivated rare cells directly in their source environments. Among the 10,000 strains of bacteria screened, teixobactin was found to be the most promising candidate and in laboratory and mice studies showed excellent activity against Gram-positive pathogens such as Streptococcus (Strep) and Staphylococcus (Staph) infections.
Teixobactin is thought to work by inhibiting cell wall synthesis by binding to two precursors of bacterial cell-wall polymers—lipid II (peptidoglycan) and lipid II (cell wall teichoic acid).
Importantly, attempts to generate teixobactin-resistant mutants to susceptible Gram-positive bacteria were unsuccessful.
Emphasizing that finding an antibiotic in the lab is just the first step in the process to developing a new drug, Dr. Wright stressed that teixobactin still needs to undergo safety and efficacy tests. “Only time will tell if this compound will go the distance,” he said.