Antimicrobial resistance, a growing threat to Human Health

The increase in antimicrobial resistance (AMR) is a direct consequence of the excessive use of antibiotics. Staphylococcus aureus and Pseudomonas aeruginosa are well-known opportunistic, potent, biofilm-producing, nosocomial and food-borne pathogens. They generally have the ability to promote intestinal diseases. The use of antibiotics for the treatment of P. aeruginosa and S. aureus infections in humans remains controversial; however, the increase in antibiotic resistance in these bacterial species is a growing cause for concern.

Human colonization by S. aureus is widespread; thirty percent of the population carries S. aureus as part of the nasopharyngeal, skin, and intestinal epithelial microbiota. Research conducted over the past few years has revealed that S. aureus colonizes the intestine of several neonates; its presence in the gut during the early developmental stages has also been associated with allergy development. This bacterium causes diseases ranging from skin infections to food-borne illnesses, and severe infections, including endocarditis, osteomyelitis, and sepsis. The biofilm-forming ability of this bacterium depends on the production of polysaccharide intercellular adhesin (PIA), encoded by the icaADBC gene cluster.

P. aeruginosa is an aerobic, Gram-negative, ubiquitous bacterium. It has a high degree of adaptability and is resistant to many antibiotics. The intestinal carriage of P. aeruginosa could be attributed to its opportunistic nature. This bacterium causes enteric disease accompanied by sepsis, which is described as “Shanghai fever”, a syndrome comprising fever, diarrhea, and sepsis; this disease was attributed to P. aeruginosa in as early as 1918. Gastrointestinal colonization with subsequent invasion into the bloodstream is the presumed mechanism underlying P. aeruginosa bacteremia in neutropenic patients. Diarrhea caused by P. aeruginosa has been observed almost exclusively in patients with prolonged antibiotic exposure. The development of antibiotic resistance is a serious side effect of current anti-pseudomonal treatments.