Question

i. Do aminoglycosides exhibit concentration dependent or concentration independent killing activity? '

ii. What are the most common bacteria associated with UTI’s in adults?

iii. Your patient’s nurse contacts you to determine if the gentamicin may be infused with the current maintenance fluids (D5W/0.9% NaCl with KCl 30 mEq/L infusing at 100 ml/hour)? What information do you provide to the nurse?

Answer 1

(i) The two major determinants of an antibiotic to kill the bacteria are time and concentration. The drug can either be time dependent or concentration dependent.

In time dependent drug, the time is the major factor. An antibiotic’s efficacy of action increases with the increase in time period for which it remains active in body. For eg : penicillin, clindamycin.

The another factor is concentration. Certain antibiotics kill bacteria when their concentration is maintained above the minimal inhibitory concentration for organism. The drug efficacy rises with rise in its concentration upto a specific level. They are called concentration dependent or dose dependent drug.

Aminoglycosides are concentration dependent drugs.

(ii) Most common bacterias causing UTI are:

1. Escherichia coli

2. chlamydia trachomatis

3. Staphylococcus aureus

4. Pseudomonas

5. Klebsiella

6. Enterobacter

7. Mycoplasma

(iii)