S. aureus Intestinal Colonization
Human intestine is a highly complex microbial ecosystem. It accommodates commensal microflora species, various types of secretory fluids, fermentation metabolites and host defense molecules that promote colonization resistance to pathogenic bacteria. However, Staphylococcus aureus, one of the most opportunistic and invasive pathogens, is capable of disrupting this colonization resistance and infecting the intestine. Patients with S. aureus intestinal colonization suffer from fecal incontinence, diarrhea, pseudomembranous colitis and so on.
Antibiotic Overuse and Superbacteria
Due to antibiotic overuse, Staphylococcus aureus develops resistance to various antibiotics and it becomes increasingly difficult to be eliminated. As a leading cause of hospital-acquired infections, methicillin-resistant S. aureus (MRSA) strains are multi-antibiotic resistant. Even the use of vancomycin — one of the last therapeutic resorts against S. aureus, becomes futile. Worse still, community-acquired MRSA strains are much more virulent and cause more morbidity and mortality than hospital-acquired MRSA.
Antimicrobial Peptides — A Promising Alternative To Antibiotics
Antimicrobial peptides (AMPs) have a reputation for their efficient antimicrobial activity against bacteria, fungi and protozoa. Despite of some promising results in clinical trials, AMPs have difficulties to be made into drugs due to their poor metabolic stability in human body. Therefore, our project aims to genetically engineer Lactococcus lactis (Grenadier Guards) to closely detect S. aureus and throw AMPs (grenades) to eradicate them within a short time after infection.
Our genetically engineered Lactococcus lactis can be made into medicines, such as enteric coated tablets, together with anti-diarrheal medicines, to cure enteritis. In addition, as an important industrial microorganism, L. lactis can be used as food additives in fermented dairy products such as cheese, and yogurt. When they inhabit in the intestinal tract, not only do they regulate micro-ecological balance, but also prevent or reduce the chance of infection.