Question

A biofilm of Staphylococcus aureus is growing on the inside of an intravascular catheter inserted into a patient's arm. The doctor recommends removing it and replacing it with a new one. Why?

• The microbes in the biofilm are antibiotic resistant and would be tough to eliminate
• The bacteria are producing toxins that degrade the catheter
• The bacteria can be transferred to a new patient when the catheter is removed
• The catheter forms a parasitic relationship with the bacteria
• The bacteria can be used to generate a vaccine to save the patient

Answer 1

S. aureus that are found in hospital setting may be antibiotic resistant strain MRSA (methicillin resistant S. aureus). S. aureus from skin can easily be transferred to the catheter where it can reside. Thus, there are increased chances that they can be transferred to the patient. MRSA can form biofilms and thus can remain within the catheter form a long time. MRSA is an opportunistic pathogen and can infect the patient. They are causes for septicemia, pneumonia, urinary tract infections etc. It is difficult to treat MRSA infections as they are resistant to many antibiotics, if the patient gets infected with MRSA via the catheter.

Toxins produced by S. aureus help in virulence during infection. However, these toxins don’t degrade catheters. There is no parasitic relationship between catheter and bacteria as catheter is mostly plastic and cannot provide any nutrient. Vaccines are produced from killed or in attenuated bacteria and not from infectious bacteria. Catheters are never reused in hospital settings.

Right choice: The microbes in the biofilm are antibiotic resistant and would be tough to eliminate.