Pharmacology Antibiotics Review: Tetracycline

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Which drug showed the highest effectiveness against methicillin resistant Staphylococcus aureus (MRSA) in the study?

Penicillin

Azithromycin

Trimethoprim (correct)

Ciprofloxacin

What percentage of fluoroquinolones were effective against methicillin susceptible Staphylococcus aureus (MSSA)?

15%

40%

5%

80% (correct)

Which drug showed resistance in 59.7% of Staphylococcus aureus isolates in the study?

Azithromycin (correct)

Vancomycin

Chloramphenicol

Penicillin

Based on the information provided, which drug is NOT mentioned as having resistance observed in the study?

Vancomycin Signup and view all the answers

Among the listed drugs, which one is NOT recommended for treating MRSA based on the study results?

Besifloxacin Signup and view all the answers

What is the main advantage of 4th generation fluoroquinolones over other fluoroquinolones?

Greater efficacy against gram-positive bacteria Signup and view all the answers

Why do bacteria need two mutations to become resistant to 4th generation fluoroquinolones?

To affect topoisomerase and efflux pumps Signup and view all the answers

What is the mechanism of action of Besifloxacin in treating bacterial conjunctivitis?

Disrupting bacterial DNA replication Signup and view all the answers

How does the 4th generation of fluoroquinolones circumvent antibiotic resistance?

By targeting a different enzyme than 2nd generation fluoroquinolones Signup and view all the answers

What is the significance of needing two mutations in bacteria to be destroyed by 4th generation fluoroquinolones?

It emphasizes the dual target approach of these antibiotics Signup and view all the answers

Which class of antibiotics is known to inhibit bacterial DNA synthesis?

Tetracyclines Signup and view all the answers

In the context of antibiotics, what is the main function of fluoroquinolones?

Affect DNA synthesis Signup and view all the answers

Besifloxacin is commonly used to treat which eye condition?

Bacterial conjunctivitis Signup and view all the answers

Which antibiotic class is most associated with resistance due to modification of the drug target?

Aminoglycosides Signup and view all the answers

What is a common characteristic of bacterial strains that show resistance to antibiotics like besifloxacin?

Reduced membrane permeability Signup and view all the answers

Which of the following fluoroquinolones showed the lowest MIC90s in the study?

Besifloxacin Signup and view all the answers

In the study, which drug had a resistance greater than 70% for fluoroquinolones?

Azithromycin Signup and view all the answers

Which drug had the highest resistance observed among the listed antibiotics in the ARMOR study?

Oxacillin Signup and view all the answers

Compared to earlier-generation fluoroquinolones, which group had lower MIC90s overall?

Besifloxacin, Gatifloxacin, Moxifloxacin Signup and view all the answers

Which antibiotic showed the highest resistance among presumed keratitis isolates during the period 2009-2019?

Ciprofloxacin Signup and view all the answers

Which antibiotic class binds to the 50S ribosomal subunit and inhibits bacterial protein synthesis?

Macrolides Signup and view all the answers

Which antibiotic is specifically mentioned for use in chlamydia and corneal ulcers?

Ciprofloxacin Signup and view all the answers

Why is the use of a sulfa + anesthetic combination not recommended?

The anesthetic contains PABA which can antagonize the sulfa component. Signup and view all the answers

Which generation of fluoroquinolones includes Levofloxacin and Moxifloxacin with superior effectiveness compared to Ciprofloxacin?

3rd Generation Signup and view all the answers

Besifloxacin is formulated in which specific vehicle for ophthalmic use?

DuraSite vehicle Signup and view all the answers

Which of the following is NOT a mechanism of antibiotic resistance mentioned in the text?

Increased antibiotic permeability Signup and view all the answers

Which class of antibiotics is mentioned in the text as being effective for ocular conditions due to their ability to affect bacterial DNA synthesis?

Fluoroquinolones Signup and view all the answers

Besifloxacin is specifically mentioned in the text as an antibiotic recommended for treating which ocular condition?

Bacterial conjunctivitis Signup and view all the answers

What is highlighted in the text as the reason for the high and stable antibiotic resistance among ocular microbes?

Inappropriate use of antibiotics Signup and view all the answers

What is one guideline highlighted for effective antimicrobial treatment of ocular conditions?

Ensuring accurate diagnosis before treatment Signup and view all the answers

Why is Besifloxacin considered effective against bacteria?

It has lower Minimum Inhibitory Concentration (MIC) for staphylococcal isolates. Signup and view all the answers

What is the significance of using a loading dose with great frequency in treating corneal ulcers?

To bombard the infection with troops initially. Signup and view all the answers

How do practitioners justify the off-label use of 4th generation fluoroquinolones to treat corneal ulcers?

By recognizing their effectiveness in treating corneal ulcers. Signup and view all the answers

What distinguishes Moxifloxacin from Gatifloxacin in terms of potency?

Moxifloxacin has greater potency against Gram-positive bacteria. Signup and view all the answers

What is the role of Polymyxin B/Neomycin/Gramicidin Solutions in ocular treatment?

To treat inflammation and bacteria simultaneously. Signup and view all the answers

What differentiates Tobradex ST from generic Tobradex?

Tobradex ST has increased staying time on the ocular surface. Signup and view all the answers

Why is it important to be cautious when using Dexamethasone in patients with glaucoma?

It has a higher correlation with increasing IOP in glaucoma patients. Signup and view all the answers