Comparative Efficacy of Quinolones and Aminoglycosides in Carbapenem-Resistant Acinetobacter Baumannii Infections

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Questions and Answers

What is the primary concern with the development of carbapenem-resistant Acinetobacter baumannii (CRAB) strains?

The limited number of novel fluoroquinolone classes for clinical use
The nephrotoxicity of quinolones
The emergence of multidrug resistance in CRAB strains (correct)
The increased use of quinolones in clinical practice

What is the characteristic of quinolones in terms of their killing effect?

Concentration-dependent and time-independent
Concentration- and time-dependent (correct)
Dose-dependent and time-independent
Dose-independent and time-dependent

Why are fluoroquinolones being reused as potential drugs in human body therapy?

In combination with other drugs and physiological weakness (correct)
Due to their concentration-dependent killing effect
Due to their nephrotoxicity
Because of their limited availability

What is the classification of quinolones by the World Health Organization?

Essential medicines (D) Signup and view all the answers

What is the limitation of the available quinolones in treating CRAB infections?

Their display of distinct features of multidrug resistance (C) Signup and view all the answers

What is the reason for the reuse of quinolones in clinical practice?

The limited therapeutic options for CRAB infections (C) Signup and view all the answers

What is the evolutionary transformation of Acinetobacter baumannii that is particularly common?

From aminoglycoside-sensitive to carbapenem-resistant strains (C) Signup and view all the answers

What is the primary goal of the present study?

To investigate the efficacy of new quinolones in treating CRAB infections (B) Signup and view all the answers

What is the primary mechanism of action of aminoglycosides against gram-negative bacteria?

Inhibiting bacterial protein synthesis (C) Signup and view all the answers

What is the primary concern with using aminoglycosides in combination with beta-lactam antibiotics for CRAB infections?

Higher risk of renal function damage (C) Signup and view all the answers

What is the primary reason for the development of new antibiotic compounds for CRAB infections?

To combat the rising threat of untreatable CRAB infections (D) Signup and view all the answers

What is the primary mechanism of resistance of Acinetobacter baumannii to antimicrobial agents?

Overexpression of OXA-type carbapenemase or carbapenemase (D) Signup and view all the answers

What is the primary goal of the study mentioned in the content?

To evaluate the efficacy of quinolones and aminoglycosides in CRAB infections (B) Signup and view all the answers

What is the primary outcome of using quinolones and aminoglycosides in CRAB-infected patients?

No impact on 30-day mortality (D) Signup and view all the answers

What is the primary advantage of using TGC and CAZ/AVI treatment in CRAB-infected patients?

Reduced 30-day mortality and ICU mortality (D) Signup and view all the answers

What is the estimated annual number of deaths in the U.S. due to bacterial infections acquired during hospital stays?

98,000 (D) Signup and view all the answers

What is the primary concern with the widespread outbreaks of CRAB infections?

Difficulty in treating CRAB infections with conventional antibiotics (B) Signup and view all the answers

What is the primary outcome of using quinolones in CRAB-infected patients?

Reduced length of hospital stay after adjustment with other potential factors (A) Signup and view all the answers

What is the primary reason for the urgent need to launch new effective antibiotics?

To reduce the mortality rate in carbapenem-resistant Acinetobacter infections (B) Signup and view all the answers

What is the challenge in treating CRAB infections?

The limited options of antibiotics (C) Signup and view all the answers

What was the primary aim of the study mentioned in the content?

To investigate the potential efficacy of quinolones in CRAB infections (C) Signup and view all the answers

What is CRAB?

A serious nosocomial pathogen (A) Signup and view all the answers

What was the outcome of the study compared to previous studies?

The results were quite different (D) Signup and view all the answers

What is the significance of the widespread dissemination of carbapenem-resistant genes?

It makes CRAB infections more difficult to treat (C) Signup and view all the answers

What is the primary mechanism of resistance to antibiotics in Acinetobacter baumannii?

Efflux pumps and outer membrane proteins (B) Signup and view all the answers

What is the optimal temperature range for the growth of Acinetobacter baumannii?

30-37 °C (D) Signup and view all the answers

What is the characteristic that allows Acinetobacter baumannii to protect itself from effector molecules?

Porin and outer membrane proteins (C) Signup and view all the answers

What is the only antimicrobial that Acinetobacter baumannii is unable to produce resistance against innately?

Carbapenems (C) Signup and view all the answers

What is the mechanism of action of aminoglycosides in treating gram-negative infections?

Inhibition of protein synthesis (D) Signup and view all the answers

What is the significance of using a nitrofurantoin with aminoglycosides in treating gram-negative infections?

To decrease the emergence of resistant bacterial strains (A) Signup and view all the answers

What is the characteristic of Acinetobacter baumannii that allows it to form biofilms on abiotic and biotic surfaces?

All of the above (D) Signup and view all the answers

What is the bacterium described as a strictly aerobic, Gram-negative, coccobacillus, non-fermentative and non-motile?

Acinetobacter baumannii (A) Signup and view all the answers

What is the derivative of quinolines used as antimicrobial agents?

Quinolones (B) Signup and view all the answers

What is the characteristic that allows Acinetobacter baumannii to use a variety of compounds as sources of carbon, nitrogen, sulfur, and phosphorus?

Non-fastidious growth requirement (B) Signup and view all the answers

What characterizes Multidrug-resistant Acinetobacter baumannii (MDR-AB)?

Resistant to carbapenem and susceptible to colistin and tigecycline (D) Signup and view all the answers

What is the main difference in action between quinolones and aminoglycosides?

Quinolones penetrate cells more easily than aminoglycosides (A) Signup and view all the answers

What was the primary objective of the study mentioned in the content?

To investigate the comparative efficacies of quinolones and aminoglycosides in treating CRE and CRAB infections (C) Signup and view all the answers

What was the finding of the study regarding the 28-day mortality in the subgroup of blood infection?

There was no significant difference between quinolones and aminoglycosides (B) Signup and view all the answers

What is a potential advantage of quinolones over aminoglycosides?

Quinolones have less nephrotoxicity or ototoxicity (C) Signup and view all the answers

What was the result of the ciprofloxacin plus amikacin treatment in the study?

It resulted in the highest cumulative survival for CRAB infections (D) Signup and view all the answers

Why do clinicians prefer to use quinolones over aminoglycosides?

Because quinolones are known to be effective or popular for treating CRAB infections (B) Signup and view all the answers

What is the significance of carbapenem resistance in A. baumannii infections?

It is a significant contributor to morbidity and mortality among hospitalized patients (B) Signup and view all the answers

What is a limitation of the use of quinolones in treating CRAB infections?

Resistance rates to quinolones have increased lately (A) Signup and view all the answers

What is the ultimate goal of the review mentioned in the content?

To find a new substitute for quinolones (D) Signup and view all the answers

What type of organisms are quinolones especially effective against?

Gram-negative organisms (D) Signup and view all the answers

What is the mechanism of carbapenem-resistance in Acinetobacter?

Inhibition of outer membrane protein (OprD) (B), Production of carbapenem-hydrolyzing class D enzymes (D) Signup and view all the answers

What is the function of OprD in Acinetobacter?

To facilitate the entry of carbapenem into the cell (A) Signup and view all the answers

What is the purpose of the study comparing quinolones and aminoglycosides in CRAB infections?

To compare the clinical efficacy of quinolones and aminoglycosides (A) Signup and view all the answers

What is the result of the absence of OprD in Acinetobacter?

Development of carbapenem-resistance (C) Signup and view all the answers

What is the mechanism of resistance caused by OXA-23 in Acinetobacter?

Hydrolysis of carbapenems (C) Signup and view all the answers

What is the result of the increase in carbapenem-resistant Acinetobacter baumannii infections?

Increased mortality rates above 50% (D) Signup and view all the answers

What is the common feature of the four quinolones mentioned in the study?

Broad antibacterial spectrum (D) Signup and view all the answers

What is the significance of Tn2006 and Tn2008 in carbapenem-resistance?

They are plasmids that contribute to carbapenem-resistance (D) Signup and view all the answers

What is the result of the overuse of carbapenem in hospital patients?

Increased incidence of carbapenem-resistant Acinetobacter (C) Signup and view all the answers

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Study Notes

Carbapenem-Resistant Acinetobacter Baumannii (CRAB) Infections

CRAB is an opportunistic pathogen commonly found in hospitals, resistant to most antibiotics, and causes hospital-acquired pneumonia, postoperative wound infections, and various infections in patients with low immunity and trauma.
CRAB is a high outbreak infectious agent that can cause serious infections and has significant economic pressure on hospitals and patients.

Quinolones and Aminoglycosides

Quinolones are essential medicines recognized by the World Health Organization, have a concentration- and time-dependent killing effect, and are not nephrotoxic.
Aminoglycosides inhibit bacterial protein synthesis, cause a bactericidal effect against gram-negative bacteria, and are often administered in combination with beta-lactams for CRAB infections.

Mechanisms of Action and Spectrum of Activity

Quinolones are especially effective against gram-negative organisms and have a broad antibacterial spectrum, inhibiting bacterial DNA synthesis.
Aminoglycosides are bactericidal against gram-negative organisms, including Escherichia coli, Klebsiella species, and Pseudomonas aeruginosa.

Mechanisms of Carbapenem-Resistance

Plasmid-mediated resistance is a widespread phenomenon, and the overuse of carbapenem can cause carbapenem to undergo highly restricted clinical treatment.
The main mechanism of carbapenem-resistance in Acinetobacter is the production of carbapenem-hydrolyzing class D enzymes, such as OXA-23, OXA-24, and OXA-58.

Clinical Studies Comparing Quinolones and Aminoglycosides

A study evaluated the clinical efficacy of quinolones and aminoglycosides in patients with CRAB infections, including 702 patients in the quinolones group and 411 in the aminoglycosides group.
Quinolones can penetrate cells more easily than aminoglycosides and have a higher efficacy than aminoglycosides in combinations.

Key Findings and Outcomes

Quinolones and aminoglycosides have relatively potent broad-spectrum activity against diverse bacterial species, but quinolones are a better choice for serious infections due to less nephrotoxicity or ototoxicity.
The study found no significant differences between quinolones and aminoglycosides in tested outcomes in the overall population or the subgroup of pneumonia.

Conclusion and Future Directions

The resistance rates to quinolones have increased, but quinolones are still a better choice for serious infections, especially when combined with amikacin.
The development of new effective antibiotics is urgently needed to overcome the infection burden of CRAB infections.

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