A 30-year-old hospitalized patient with an intravenous (IV) catheter developed fever and systemic infection. The source of the infection was bacteria that contaminated the catheter during its insertion. The IV catheter had to be removed because the bacteria grew within the catheter forming a biofilm. Biofilm development depends on the ability of the bacteria to produce which of the following?
Pathogenic bacteria such as the gram-negative bacillus Pseudomonas aeruginosa and the gram-positive coccus Staphylococcus aureus colonize the surface of certain surgical appliances such as artificial heart valves and catheters. Multiple layers of the colonizing bacteria surround themselves with a polysaccharide (c) matrix, which protects them from the effect of antibiotics and host immune defenses. The remaining choices do not contribute to biofilm development. Porins (d), proteins that are located within the outer membrane of gram-negative bacteria, facilitate the transfer of hydrophilic molecules through the membrane. Teichoic acids (e) found within the cell wall of gram-positive bacteria are anionic polymers of polyglycan that provide rigidity to the cell wall. In gram-negative bacteria, the periplasmic space occupies the area between the external surface of the cytoplasmic membrane and the internal surface of the outer membrane. The periplasm (b) contains hydrolytic enzymes, virulence proteins, and components of the sugar transport systems. Endotoxin (LPS), a component of the outer membrane of gram-negative bacteria, is recognized by the host defenses and stimulates macrophages to produce cytokines.
Endotoxin
Periplasm
Polysaccharides
Porins
General