Bio 205: Two Discussion Questions

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The role of microorganisms in disease is extremely relevant to my current and future jobs in the healthcare field. One of this year’s goals in the hospital is to reduce the number of CAUTIs (Catheter Acquired Urinary Tract Infection). This is when a microorganism is able to make its way into the urinary tract from the insertion and prolonged placement of a catheter. These can be prevented with proper aseptic technique and proper maintenance of the catheter. Understanding that microorganisms cause this problem is key to help preventing any infections.

2. The antibiotic (antimicrobial) amphotericin B causes leaks in cells by combining with sterols in the plasma membrane. Would you expect to use amphotericin B against a bacterial infection? A fungal infection? Offer a reason why amphotericin B has severe side effects in humans.

Answer below:

The antibiotic amphotericin B combines with sterols to cause damage to cells. Sterols are a subgroup of steroids that are found in the cell membranes of prokaryotic organisms. These sterols are an important part of maintaining the fluidity of the membrane. Being prokaryotic these sterols are not found in bacterial membranes, they have another compound called hopanoids. Since bacteria lack the sterols amphotericin has no effect on bacteria. The amphotericin cannot combine with anything and cause the leaking of the cell. Fungi on the other hand do have sterols present in the membrane. Therefore amphotericin is an effective treatment in fungal infections. This treatment of amphotericin will cause side effects because human cells also contain sterols in the membrane. The amphotericin will combine with the cholesterol in the plasma membranes and cause the leaking and damage. This would cause even healthy cells to leak, which can result in swollen/painful joints, pulmonary edema, pedal edema, excessive urination, etc. This is why amphotericin is only recommended to be used in severe fungal infections.

Being a healthcare professional and giving many different medications with may effects, understanding how a medication works in the body is very important to foreseeing any side effects from it. Every medication has the risk of side effects so as a healthcare provider you have to weigh the intended effects against the side effects to see if it is worth the risk to give to a patient.