NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

What type of activity do 3rd generation cephalosporins such as ceftriaxone, cefotaxime, and ceftazidime have?

1. No gram-positive activity, covers Pseudomonas

2. Resistant strep, MSSA, gram-positive anaerobes and resistant HNPEK

3. Broad GN activity including HNPEK, CAPES, Pseudomonas

4. None of the above

The correct answer is: Resistant strep, MSSA, gram-positive anaerobes and resistant HNPEK

3rd generation cephalosporins like ceftriaxone, cefotaxime, and ceftazidime are known for their broad spectrum of activity. They have good activity against Gram-positive cocci, including Staphylococcus aureus and Streptococcus pneumoniae. These antibiotics are also effective against a variety of Gram-negative bacteria, such as Haemophilus influenzae, Neisseria gonorrhoeae, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae. Additionally, they exhibit enhanced activity against some anaerobic bacteria. Therefore, option B is the correct choice as it correctly describes the spectrum of activity exhibited by 3rd generation cephalosporins. Option A is incorrect because 3rd generation cephalosporins do have some gram-positive activity and cover Pseudomonas. Option C is incorrect because it overstates the spectrum of activity by including CAPES (Citrobacter, Acinetobacter, Pseudomonas, Enterobacter, and Serratia), which are typically covered by broader-spectrum antibiotics like carbapenems. Option D is incorrect as mentioned above.