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[Gram-negative rods: antibacterial agents effective on gram-negative rods]
1Laboratory of Drug-resistance in Bacteria, Gunma University School of Medicine.
Abstract:
Some kinds of gram-negative rods cause serious infections in the compromised hosts. The species most frequently isolated in big hospitals are P. aeruginosa, E. coli, K. pneumoniae, E. cloacae, S. marcescens, and H. influenzae. Among these species. P. aeruginosa, E. cloacae and S. marcescens show resistance to many antibacterial agents. The aminoglycoside, such as gentamicin, is effective against these strains but resistant strains are detected at a high frequency for P. aeruginosa. Resistant strains to new quinolones are isolated for both S. marcescens and P. aeruginosa. The third generation cephems are effective against these species but they easily acquire resistance to these drugs. Imipenem and cefclidin are effective and a few resistant strains to the drugs are already detectable in gram-negative rods.
Insights
Gram-negative rods like Pseudomonas aeruginosa cause severe infections. Antibiotic resistance is a growing concern, with strains resisting gentamicin, new quinolones, and third-generation cephems.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Gram-negative rods are significant pathogens, particularly in immunocompromised patients.
- Commonly isolated species include Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens, and Haemophilus influenzae.
- Several of these species exhibit resistance to multiple antibacterial agents.
Purpose of the Study:
- To investigate the prevalence of antibiotic resistance in clinically significant gram-negative rods.
- To assess the effectiveness of common antibiotics against these resistant strains.
Main Methods:
- Isolation and identification of gram-negative bacterial species from hospital settings.
- Antimicrobial susceptibility testing against various antibiotic classes (aminoglycosides, new quinolones, third-generation cephems, imipenem, cefclidin).
Main Results:
- Pseudomonas aeruginosa, Enterobacter cloacae, and Serratia marcescens demonstrate resistance to numerous antibacterial agents.
- High-frequency resistance to gentamicin observed in P. aeruginosa.
- Emergence of resistance to new quinolones in S. marcescens and P. aeruginosa.
- While third-generation cephems are effective, rapid resistance development occurs.
- Imipenem and cefclidin show effectiveness, though some resistant strains are emerging.
Conclusions:
- Antibiotic resistance is a significant challenge in managing gram-negative rod infections.
- Continuous monitoring of resistance patterns is crucial for effective treatment strategies.
- The emergence of resistance to last-resort antibiotics like imipenem and cefclidin warrants attention.