Fluoroquinolone resistance during 2000-2005: an observational study

Area of Science:

• Infectious Diseases
• Microbiology
• Pharmacology

Background:

• Moxifloxacin, a respiratory fluoroquinolone, is indicated for community-acquired pneumonia.
• Unlike other fluoroquinolones, moxifloxacin has low urinary excretion.
• Hypothesis: Increased moxifloxacin use is linked to rising fluoroquinolone resistance in Gram-negative uropathogens.

Purpose of the Study:

• To investigate the association between moxifloxacin usage and fluoroquinolone resistance in Gram-negative bacteria.
• To compare the impact of moxifloxacin on resistance with other fluoroquinolones.

Main Methods:

• Antibiograms for Gram-negative bacteria from 2000-2005 were analyzed.
• Defined Daily Doses (DDD) per 1000 bed days were calculated for each fluoroquinolone.
• Pearson's Correlation Coefficient (r) assessed the relationship between fluoroquinolone use and bacterial susceptibility.

Main Results:

• Fluoroquinolone use decreased from 237.2 to 115.2 DDD/1000 bed days between 2000 and 2005.
• Moxifloxacin use showed a negative correlation with sensitivity in 12 out of 13 Gram-negative species.
• Aggregated data indicated increased sensitivity with other fluoroquinolones but decreased sensitivity with moxifloxacin.

Conclusions:

• Moxifloxacin use may negatively influence local antibiotic sensitivities in Gram-negative organisms.
• This resistance-promoting effect was specific to moxifloxacin and not observed with other fluoroquinolones.
• The findings highlight potential unintended consequences of moxifloxacin use on antimicrobial resistance patterns.