Scientists have identified a structural reason why Clostridium difficile may be so difficult to eradicate, according to findings published Feb. 25 in Nature Communications.
Scientists from several U.K. universities outlined the structure of the main protein, SlpA, that forms links of flexible and protective armor of the superbug. They discovered the armor is made of a close-knit yet flexible outer layer similar to chain mail. The diarrhea-causing superbug Clostridium difficile uses the armor that covers the cell of the whole bacteria — the surface layer or S-layer — to protect itself from antibiotics and immune responses.
"I started working on this structure more than 10 years ago — it's been a long, hard journey but we got some really exciting results!" Paula Salgado, PhD, structural microbiologist and study author, said in a Feb. 25 news release. "Surprisingly, we found that the protein forming the outer layer, SlpA, packs very tightly, with very narrow openings that allow very few molecules to enter the cells. S-layer from other bacteria studied so far tend to have wider gaps, allowing bigger molecules to penetrate. This may explain the success of C.diff at defending itself against the antibiotics and immune system molecules sent to attack it."
Currently, C. diff is resistant to all but three drugs. Antimicrobial resistance, declared by the World Health Organization a top global public health threat, is a main problem when attempting to rid of the bacteria.
"Excitingly, it also opens the possibility of developing drugs that target the interactions that make up the chain mail," Dr. Salgado said. "If we break these, we can create holes that allow drugs and immune system molecules to enter the cell and kill it."