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Changing trends in ocular infections

Changing trends . Surveillance trends indicate that the rates of resistance in isolates taken from serious ocular infections, whether involving the cornea or the intraocular compartment are increasing.These trends are of major concern to the ophthalmologists seeking to prevent postsurgical ocular infections..

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Changing trends in ocular infections

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    1. Changing trends in ocular infections 4th generation fluoroquinolones : Arsenals in treating ocular infections

    3. Changing trends In a 5-year study on trends in resistance, Goldstein and colleagues found the vast majority of isolates were gram-positives versus gram negatives. (N= 797 vs N= 256, respectively).

    4. Changing trends:Ocular infections

    5. Emerging resistance Recent reports of ocular bacterial resistance to the second generation fluoroquinolones has threatened their success .

    6. Emerging resistance In 2001, The Charles T Campbell Eye Microbiology Lab found 100% of all S. aureus isolates cultured in cases of endophthalmitis were resistant to ciprofloxacin, ofloxacin and levofloxacin. Ophthalmology Times 2003, 28(5), 1-15

    7. Increasing resistance to fluoroquinolones

    8. Increasing resistance to fluoroquinolones S. aureus resistance to ciprofloxacin 5.8% in 1993 to 35% in 1997 S. aureus resistance to ofloxacin 4.7% in 1993 to 35% in 1997

    9. Development of fourth generation fluoroquinolones A rising incidence of postoperative endophthalmitis and bacterial keratitis, combined with the steady increase in resistance to traditional fluoroquinolone therapies has lead to development of the new generation of fluoroquinolones.

    10. Fourth generation fluoroquinolones The 2 representatives of this new generation to be approved by the U.S FDA are gatifloxacin and moxifloxacin. Both the drugs have a unique 8-methoxy structure.

    11. Gatifloxacin : Fourth generation fluoroquinolone

    12. Gatifloxacin: Clinical Efficacy

    13. Ocular isolates: Susceptibility of gatifloxacin to resistant strains Aim: To determine susceptibility of ocular lesions to gatifloxacin, levofloxacin & ciprofloxacin. Methods: Conjunctival swabs were taken from patients with conjunctivitis prior to antibacterial therapy. MICs were then determined. Results: All gram-positive ocular isolates (n=170) were susceptible to gatifloxacin.

    14. Susceptibility of gatifloxacin to resistant strains RESULTS: 2.9% and 7.6% of S. epidermidis which were fully resistant to levofloxacin and ciprofloxacin were susceptible to gatifloxacin. All gram-negative isolates (n=65) were susceptible to all 3 antibacterials.

    15. Role of gatifloxacin: Multiple drug-resistant Staphylococcal Keratitis Aim: To assess the efficacy of gatifloxacin for treatment of multiple drug-resistant Staphylococcus Keratitis after Lamellar Keratectomy. Method: N= 28 New Zealand white rabbits. Ocular infection was induced in them. Eyes were then randomized and treated immediately & 6,12, 18 hours after surgery with one drop of balanced salt solution, gatifloxacin (0.3%), ciprofloxacin(0.3%),or levofloxacin(0.5%)

    16. Role of gatifloxacin: Multiple drug-resistant Staphylococcal Keratitis

    17. Gatifloxacin : Bacterial conjunctivitis

    18. Penetration of gatifloxacin Aim: To compare the aqueous penetration of newer fluoroquinolone antibiotic gatifloxacin with that of ofloxacin and ciprofloxacin. Method: N= 20 New Zealand white rabbits. were dosed with commercial topical preparation of gatifloxacin, ciprofloxacin and ofloxacin. (2 drops in each eye at 90, 85, 80, 60, and 30 minutes preoperatively) The aqueous was then sampled and analyzed using reversed phase HPLC.

    19. Penetration of gatifloxacin Results: Gatifloxacin, Ciprofloxacin and Ofloxacin achieved a mean aqueous concentration of 2.4817 mcg/ml, 0.9616 mcg/ml and 2.5136 mcg/ml respectively.Ofloxacin achieved a concentration no different than gatifloxacin (p= 0.963). Conclusion: Gatifloxacin has aqueous penetration in excess of the reported MIC90 of likely pathogens when dosed topically. The penetration of gatifloxacin compared favorably to that of established fluoroquinolone agents.

    20. Conclusion Until recently, third generation fluoroquinolones were relatively well-equipped to take the task of prophylaxis. With the introduction of the newest generation of fluoroquinolones, surgeons have more power to fight bacterial infections.

    21. The dual advantage offered by fourth generation fluoroquinolones (gatifloxacin) will quickly position them as the antimicrobials of choice in the prevention and treatment of bacterial keratitis and endophthalmitis.

    22. Conclusion ‘‘ Put simply, if we use some of the small guns first, we give the bacteria a chance to develop resistance mechanisms that allow them to then overcome the bigger guns. A more effective strategy appears to be to use the bigger guns first, as long as we use them judiciously’’ David G. Hwang Director, Cornea and Refractive Surgery Service San Francisco, California

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