Original article
Fourth generation fluoroquinolones: new weapons in the arsenal of ophthalmic antibiotics1

Data from this manuscript have been presented at the 2001 ARVO meeting in Fort Lauderdale, FL and at the 2001 OMIG meeting in New Orleans, LA
https://doi.org/10.1016/S0002-9394(02)01334-XGet rights and content

Abstract

PURPOSE: Fourth generation fluoroquinolones (FQs) will soon be introduced to ophthalmology. In this in vitro study, differences in the susceptibility patterns and the potencies of fourth generation FQs (gatifloxacin-GAT and moxifloxacin-MOX) were compared with third generation (levofloxacin-LEV) and second generation FQs (ciprofloxacin-CIP and ofloxacin-OFX).

DESIGN: Experimental laboratory investigation.

METHODS: In retrospect, the minimum inhibitory concentrations (MICs) of 93 bacterial endophthalmitis isolates were determined to CIP, OFX, LEV, GAT, and MOX using E-tests. The National Committee of Clinical Laboratory Standards (NCCLS) susceptibility patterns and the potencies of the MICs were statistically compared.

RESULTS: With in vitro tests, Staphylococcus aureus isolates that were resistant to CIP and OFX were statistically most susceptible (P = .01) to MOX. Coagulase negative Staphylococci that were resistant to CIP and OFX were statistically most susceptible (P = .02) to MOX and GAT. Streptococcus viridans were more susceptible (P = .02) to MOX, GAT, and LEV than CIP and OFX. Streptococcus pneumoniae was least susceptible (P = .01) to OFX compared with the other FQs. Susceptibilities were equivalent (P = .11) for all other bacterial groups. In general, MOX was the most potent FQ for gram-positive bacteria (P = .05) while CIP, MOX, GAT, and LEV demonstrated equivalent potencies to gram-negative bacteria.

CONCLUSIONS: This in vitro study indicated that fourth generation FQs appear to cover bacterial resistance to the second and third generation FQs, were more potent than the second and third generation FQs for gram-positive bacteria, and are equally potent for gram-negative bacteria. Clinical studies will need to confirm these results.

Section snippets

Design

The in vitro susceptibilities and potencies of ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin, and gatifloxacin were compared in a retrospective laboratory study using bacteria isolated from clinical cases of endophthalmitis.

Methods

The minimum inhibitory concentrations (MICs) (μg/ml) of 93 bacterial endophthalmitis isolates were determined to ciprofloxacin, ofloxacin, levofloxacin, moxifloxacin, and gatifloxacin using E-tests (AB Biodisk, Piscataway, NJ). The isolates included eight isolates of Staphylococcus aureus that were resistant to ciprofloxacin and ofloxacin as determined by disk diffusion; six isolates of Staphylococcus aureus that were susceptible to ciprofloxacin and ofloxacin as determined by disk diffusion;

Results

Table 1summarizes the susceptibility results of 93 endophthalmitis isolates to ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and moxifloxacin based on the NCCLS serum standards. Second-generation fluoroquinolone-resistant Staphylococcus aureus was statistically more susceptible (P = .01) to moxifloxacin than the other fluoroquinolones. Coagulase negative staphylococci were statistically more susceptible (P = .02) to gatifloxacin and moxifloxacin than levofloxacin, ciprofloxacin, and

Discussion

We are at the advent of the introduction of new generations of fluoroquinolone antibiotics for ocular therapy. The question to be asked is whether there will be any forthcoming advantage over the present generation fluoroquinolones. These new antibiotics were developed primarily for the treatment of systemic infections such as pneumonia. In this setting, they have demonstrated a broad spectrum of activity with greater potency for gram-positive bacteria (that is, Streptococci, Staphylococci) as

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Cited by (0)

1

The Eye and Ear Foundation of Pittsburgh (Pittsburgh, PA) was given a core grant for Vision Research EY 08098 and Research to Prevent Blindness. The first author (R.M.) was granted travel support for ARVO 2001 in Fort Lauderdale, FL by Alcon (Fort Worth, TX).

2

The authors have no proprietary interest in any of the antibiotics presented in this manuscript.

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