In vitro susceptibility of recent gram-positive isolates to ciprofloxacin, levofloxacin, and trovafloxacin

A phase III clinical trial of 0.5% levofloxacin ophthalmic solution versus 0.3% ofloxacin ophthalmic solution for the treatment of bacterial conjunctivitis

OBJECTIVE

To compare the efficacy and safety of 0.5% levofloxacin ophthalmic solution (QUIXIN) with 0.3% ofloxacin ophthalmic solution for the treatment of bacterial conjunctivitis.

DESIGN

Prospective, randomized, active-controlled, double-masked, multicenter study.

PARTICIPANTS

Four hundred twenty-three patients with a clinical diagnosis of bacterial conjunctivitis were enrolled.

METHODS

Patients were randomly assigned to receive either 0.5% levofloxacin (n = 211) or 0.3% ofloxacin (n = 212) for 5 days (every 2 hours on days 1 and 2 and every 4 hours on days 3-5). Conjunctival cultures were obtained, and ocular signs and symptoms were evaluated on day 1 (baseline), days 3 to 5 (interim), and days 6 to 10 (final). End point was defined as the last evaluable observation.

MAIN OUTCOME MEASURES

Primary microbial and clinical outcomes were based on culture results and resolution of cardinal signs, respectively. Secondary efficacy assessments included evaluations of ocular signs and symptoms.

RESULTS

Two hundred eight patients (levofloxacin, n = 109; ofloxacin, n = 99) were evaluated for efficacy. Microbial eradication rates were significantly greater in the 0.5% levofloxacin treatment group compared with the 0.3% ofloxacin group at both the final visit (89% vs. 80%, P = 0.034) and at end point (90% vs. 81%; P = 0.038). Treatment with 0.5% levofloxacin was significantly more effective in resolving photophobia than was 0.3% ofloxacin treatment (94% vs. 73%, P = 0.006). Both study medications were well tolerated, with a low incidence of adverse events.

CONCLUSIONS

Although clinical cure rates in the 0.5% levofloxacin and 0.3% ofloxacin treatment groups were similar, a 5-day treatment regimen with 0.5% levofloxacin achieved microbial eradication rates that were statistically superior to those attained with 0.3% ofloxacin. Despite the higher concentration of active drug in 0.5% levofloxacin versus 0.3% ofloxacin, there was no difference between treatment groups in the incidence of treatment-related adverse events.

Pneumococcal resistance: the treatment challenge

OBJECTIVE

To review in vitro and in vivo information dealing with pneumococcal antibiotic resistance and provide a review of the incidence, mechanisms, and controversies surrounding this growing problem. The review is also intended to provide clinicians with relevant recommendations on treatment and prevention of this organism.

DATA SOURCES AND SELECTION

Primary and review articles were identified by MEDLINE search (1966-August 2000) and through secondary resources such as conference proceedings. All of the articles identified from the data sources were evaluated, and all information deemed relevant was included in this review.

DATA SYNTHESIS

The growing incidence and reporting of pneumococcal isolates that are resistant to one or more classes of antibiotics have become a troubling trend that has resulted in significant shifts in treatment. Although clinicians have shifted to a new generation or class of antibiotics when faced with a resistance trend, data with resistant pneumococci show that this may not be necessary. By incorporating the pharmacokinetic and pharmacodynamic data of antimicrobials into the decision-making process, many of the drugs that we have become hesitant to use due to this resistance may still be appropriate if used correctly.

CONCLUSIONS

Appropriate dosing of antimicrobials, combined with optimal use of pneumococcal vaccines, will not only prolong the longevity of some agents, but also hopefully slow resistance development.

Comparative in vitro activity of gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin and trovafloxacin against 4151 Gram-negative and Gram-positive organisms

Gatifloxacin, grepafloxacin, moxifloxacin and trovafloxacin are fluoroquinolones with enhanced Gram-positive activity while retaining broad-spectrum activity against Gram-negative pathogens. Levofloxacin and ciprofloxacin are older quinolones with broad activity against Gram-negative pathogens and borderline activity against some Gram-positive organisms. We compared the in vitro activity of these compounds against 4151 Gram-negative and -positive organisms. Gatifloxacin, grepafloxacin, moxifloxacin and trovafloxacin were highly active against penicillin sensitive and resistant Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes and Streptococcus agalactiae. Ciprofloxacin and levofloxacin were active but less potent. All compounds were highly active (overall) against Gram-negative pathogens with ciprofloxacin being the most active agent against Pseudomonas aeruginosa. Our data indicate that the advanced fluoroquinolones will be important compounds for treating infections caused by Gram-positive and Gram-negative pathogens.