Limitations of Current Antibiotics for the Treatment of Bacterial Conjunctivitis

Abstract

Bacterial conjunctivitis is a common ocular infection that is generally treated empirically with a broad-spectrum antibiotic. The more common pathogens causing bacterial conjunctivitis include Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus epidermidis, and Moraxella species. Several antibiotics traditionally used to treat bacterial conjunctivitis are no longer widely prescribed because of increased bacterial resistance and/or safety concerns. The introduction of the fluoroquinolone class of anti-infectives offered effective and better tolerated treatment options. Nonetheless, successful therapy for bacterial conjunctivitis continues to be limited by several factors. A primary concern is the development of bacterial resistance that may be impacted not only by widespread antibiotic use but also by antibacterial pharmacokinetics, such as maintenance of insufficient bactericidal concentrations at the site of infection. In addition, poor adherence to prescribed regimens that require frequent administration, along with undesirable adverse events, affects the development of bacterial resistance and the success of treatment regimens. This article reviews current antibacterial agents used to treat bacterial conjunctivitis, factors that limit their successful use in treatment, and options for future development of more effective topical ophthalmic anti-infective agents.

Besifloxacin in the management of bacterial infections of the ocular surface

“…These include shorter disease duration; prevention of spread of infection; reduction in adverse events (AEs), including those threatening vision; and reduced disease recurrence. 14,15 The socioeconomic impact of these benefits are significant, with decreased absenteeism from school and work. Moreover, the presence of red eyes may constitute a social and psychological burden 16 driving demand for medical treatment.…”

“…This balanced, dual action may also partially account for the lower rate of resistance development to besifloxacin compared with older fluoroquinolones that preferentially target either one of these enzymes, because dual mutations are required for development of high-level resistance to besifloxacin. 15 A mutant-selection study showed that the proportion of isolates acquiring resistance to besifloxacin was nearly 2 orders of magnitude lower than those developing resistance to ciprofloxacin 23 ; further, because besifloxacin is not used for systemic indications, there is no possibility of developing resistance subsequent to systemic use. However, cross-resistance from bacteria developing resistance to other fluoroquinolones is still possible.…”

“…20,21 Compared with other classes of antibiotics, topical fluoroquinolones are preferred for treating bacterial conjunctivitis, because they offer safety and broad-spectrum efficacy against disease-specific bacteria. 15 Earlier second-generation fluoroquinolones include ciprofloxacin and ofloxacin; these were followed by the third-generation fluoroquinolone, levofloxacin; the fourth-generation fluoroquinolones, gatifloxacin and moxifloxacin; and most recently, besifloxacin, the first topical chlorofluoroquinolone. 22 In the following section, we discuss antibiotic resistance and the development of newer fluoroquinolones to combat drug-resistant strains.…”

“…Additional factors include globalization and migration with resultant cross-transmission of resistance, health care policies that affect specific usage factors, and biological characteristics of specific bacterial species predisposing them to the development of resistance. 15 Fluoroquinolones are used in a variety of infections. Similar to other fluoroquinolones, besifloxacin acts by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes that catalyze negative supercoiling of DNA and participate in decatenation, respectively.…”

An Update on Neonatal and Pediatric Conjunctivitis

“…Topical antibiotics alone are effective in most cases of bacterial conjunctivitis, except in cases of gonococcal and chlamydial infection, which require systemic treatment [54]. Fluoroquinolones or aminoglycoside drops are an excellent initial choice of therapy for bacterial conjunctivitis.…”