[Gram-negative rods: antibacterial agents effective on gram-negative rods]

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.