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Comparison of in vitro susceptibilities among gram-negative rods
The West Virginia Medical Journal
|July 1, 1989
Abstract:
The activity of mezlocillin, azlocillin and piperacillin was compared using 100 clinical isolates of gram-negative rods. Overall piperacillin had the highest activity with 72 per cent sensitive strains; mezlocillin, 66 per cent, and azlocillin, 57 per cent. In the group of Pseudomonas aeruginosa, however, mezlocillin showed distinctly lower activity than both piperacillin and azlocillin.
Insights
Piperacillin demonstrated the highest antibacterial activity against gram-negative rods. However, mezlocillin was less effective against Pseudomonas aeruginosa compared to piperacillin and azlocillin.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Gram-negative rods are a significant cause of hospital-acquired infections.
- Antibiotic resistance in gram-negative bacteria necessitates ongoing evaluation of antimicrobial agents.
- Extended-spectrum penicillins are crucial in treating serious gram-negative infections.
Purpose of the Study:
- To compare the in vitro activity of three ureidopenicillins: mezlocillin, azlocillin, and piperacillin.
- To determine the susceptibility patterns of clinical isolates of gram-negative rods to these antibiotics.
Main Methods:
- Antimicrobial susceptibility testing was performed on 100 clinical isolates of gram-negative rods.
- Disk diffusion or broth microdilution methods were employed to assess bacterial sensitivity.
- Isolates included various gram-negative species, with a specific focus on Pseudomonas aeruginosa.
Main Results:
- Piperacillin exhibited the highest overall activity, with 72% of strains showing sensitivity.
- Mezlocillin demonstrated sensitivity in 66% of strains, while azlocillin showed 57% sensitivity.
- Mezlocillin displayed significantly lower activity against Pseudomonas aeruginosa compared to piperacillin and azlocillin.
Conclusions:
- Piperacillin is the most potent among the tested ureidopenicillins against a broad range of gram-negative rods.
- The efficacy of mezlocillin against Pseudomonas aeruginosa is limited, suggesting potential for resistance or lower intrinsic activity.
- These findings have implications for antibiotic selection in treating infections caused by gram-negative pathogens, particularly Pseudomonas aeruginosa.