The role of topical moxifloxacin, a new antibacterial in Europe, in the treatment of bacterial conjunctivitis

Topical Antibiotic Therapy in the Ocular Environment: The Benefits of Using Moxifloxacin Eyedrops

Moxifloxacin is a fourth-generation fluoroquinolone antibiotic available for ophthalmic use. It inhibits two enzymes involved in bacterial DNA synthesis, covering Gram-positive and Gram-negative pathogens. This spectrum allows for the formulation of self-preserving bottle solutions, while its interesting pharmacological profile is distinguished by efficacy at low tissue concentrations and by an infrequent dose regimen due to its long duration on ocular tissues. This enhances patient compliance, promoting its use in children. The human eye hosts several microorganisms; this collection is called the ocular microbiota, which protects the ocular surface, assuring homeostasis. When choosing an antibiotic, it is appropriate to consider its influence on microbiota. A short dose regimen is preferred to minimize the impact of the drug. Moxifloxacin eyedrops represent an effective and safe tool to manage and prevent ocular infections. As healthcare providers face the complexity of the ocular microbiota and microbial resistance daily, the informed use of moxifloxacin is necessary to preserve its efficacy in the future. In this regard, it is well known that moxifloxacin has a lower capacity to induce resistance (an optimal WPC and MPC) compared to other quinolones, but much still needs to be explored regarding the impact that fluoroquinolones could have on the ocular microbiota.

Trends in antibiotic resistance in ocular samples in a tertiary eye centre in Saudi Arabia in 2003-2019

OBJECTIVE

The aim of this study was to analyze the antibiotic resistance in ocular samples over a 16-year period.

METHODS

This was a retrospective cohort study conducted at King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia (2003-2019). The study included corneal and conjunctival swabs and aqueous and vitreous samples.

RESULTS

Coagulase-negative staphylococci exhibited a significant trend of increasing resistance over time to erythromycin (p < 0.001), oxacillin (p < 0.001), fusidic acid (p < 0.001), and moxifloxacin (p = 0.003). Staphylococcus aureus also showed a significant increase in oxacillin (p = 0.001), ofloxacin (p = 0.003), and moxifloxacin (p = 0.001) resistance patterns. Streptococcus pneumoniae demonstrated a significant increase in resistance to erythromycin (p = 0.01) and ofloxacin, which jumped from 0.80% in 2003 to 80% in 2019 (p = 0.015). No statistically significant increase in antibiotic resistance trend was observed for Pseudomonas.

CONCLUSIONS

An increasing antibiotic resistance pattern was demonstrated, particularly among gram-positive organisms. Such findings warrant revision of the common ocular antibiotic prescribing strategy and consideration of alternative antibiotics.

Antibiotic resistance in ocular bacterial infections: an integrative review of ophthalmic chloramphenicol

INTRODUCTION

Chloramphenicol is a broad-spectrum antibiotic widely used for treating ophthalmic infections, but concerns about rising bacterial resistance to chloramphenicol have been observed due to its frequent use as an over-the-counter medication. This review assessed the common ophthalmic bacterial pathogens, their chloramphenicol resistance mechanisms, and rates of drug resistance.

METHODS

PubMed and Google Scholar databases were searched for relevant publications from the years 2000 to 2022, bordering on ophthalmic bacterial infections, chloramphenicol susceptibility profiles, and drug resistance mechanisms against chloramphenicol. A total of 53 journal publications met the inclusion criteria, with data on the antibiotic susceptibility profiles available in 44 of the reviewed studies, which were extracted and analyzed.

RESULTS

The mean resistance rates to chloramphenicol from antibiotic susceptibility profiles varied between 0% and 74.1%, with the majority of the studies (86.4%) showing chloramphenicol resistance rates below 50%, and more than half (23 out of 44) of the studies showed resistance rates lower than 20%. The majority of the publications (n = 27; 61.4%) were from developed nations, compared to developing nations (n = 14; 31.8%), while a fraction (n = 3; 6.8%) of the studies were regional cohort studies in Europe, with no country-specific drug resistance rates. No pattern of cumulative increase or decrease in ophthalmic bacterial resistance to chloramphenicol was observed.

CONCLUSIONS

Chloramphenicol is still active against ophthalmic bacterial infections and is suitable as a topical antibiotic for ophthalmic infections. However, concerns remain about the drug becoming unsuitable in the long run due to some proof of high drug resistance rates.

Clinical Characterization of Inpatients with Acute Conjunctivitis: A Retrospective Analysis by Natural Language Processing and Machine Learning

Background Acute bacterial conjunctivitis (ABC) is a relatively common medical condition caused by different pathogens. Although it rarely threatens vision, it is one of the most common conditions that cause red eyes and may be accompanied by discomfort and discharge. The study aimed to identify and characterize inpatients with ABC treated with topical antibiotics. Methods The EHRead® technology, based on natural language processing (NLP) and machine learning, was used to extract and analyze the clinical information in the electronic health records (EHRs) of antibiotic-treated patients with conjunctivitis and admitted to five hospitals in Spain between January 2014 and December 2018. Categorical variables were described by frequency, whereas numerical variables included the mean, standard deviation, median, and quartiles. Results From a source population of 2,071,812 adult patients who attended the participating hospitals in the study period, 11,110 patients diagnosed with acute conjunctivitis were identified. Six thousand five hundred eighty-three patients were treated with antibiotics, comprising the final study population. Microbiology was tested only on 12.1% of patients. Antibiotics, mainly tobramycin, and corticosteroids, mainly dexamethasone, were usually prescribed. NSAIDs were also used in about 50% of patients, always combined with antibiotics. Conclusions The present study provided a realistic representation of the hospital practice concerning managing patients with acute antibiotic-treated conjunctivitis. The diagnosis is usually based on the clinical ground, microbiology is rarely tested, few bacteria species are involved, and local antibiotics are frequently associated with corticosteroids and/or NSAIDs. Moreover, this study provided clinically relevant outcomes, based on new technology, that could be applied in clinical practice.

Ciprofloxacin-Loaded Zein/Hyaluronic Acid Nanoparticles for Ocular Mucosa Delivery

Bacterial conjunctivitis is a worldwide problem that, if untreated, can lead to severe complications, such as visual impairment and blindness. Topical administration of ciprofloxacin is one of the most common treatments for this infection; however, topical therapeutic delivery to the eye is quite challenging. To tackle this, nanomedicine presents several advantages compared to conventional ophthalmic dosage forms. Herein, the flash nanoprecipitation technique was applied to produce zein and hyaluronic acid nanoparticles loaded with ciprofloxacin (ZeinCPX_HA NPs). ZeinCPX_HA NPs exhibited a hydrodynamic diameter of <200 nm and polydispersity index of <0.3, suitable for ocular drug delivery. In addition, the freeze-drying of the nanoparticles was achieved by using mannitol as a cryoprotectant, allowing their resuspension in water without modifying the physicochemical properties. Moreover, the biocompatibility of nanoparticles was confirmed by in vitro assays. Furthermore, a high encapsulation efficiency was achieved, and a release profile with an initial burst was followed by a prolonged release of ciprofloxacin up to 24 h. Overall, the obtained results suggest ZeinCPX_HA NPs as an alternative to the common topical dosage forms available on the market to treat conjunctivitis.

Comparative Study of Ocular Pharmacokinetics of Topical 0.3% Gatifloxacin Eye Gel and Solution in Rabbits

Few articles have reported drug concentrations of different ophthalmic dosage forms in the ocular tissues. This study aimed to determine the ocular pharmacokinetics of gatifloxacin 0.3% eye gel (GTX-Gel) and gatifloxacin 0.3% eye solution (GTX-Sol) at different time intervals after topical instillation in rabbits. A total of 126 healthy New Zealand rabbits were included, of which six rabbits did not receive antibiotics (control group). The remaining rabbits were randomly divided into four groups. GTX-Gel and GTX-Sol (50 μL) were topically instilled every hour in groups A1 and B1, respectively, and every two hours in groups A2 and B2, respectively, for 12 h. Ocular tissues were collected 2, 4, 8, 12, and 24 h after administration. Gatifloxacin concentration was measured using high-performance liquid chromatography coupled with tandem mass spectrometry. The drug reached peak concentrations (Cmax) in all tissues at 8−12 h. With the same administration frequency, the Cmax was higher with GTX-Gel than with GTX-Sol (p < 0.05). Except for the iris-ciliary body, other ocular tissues did not show significant difference (p > 0.05) in gatifloxacin concentration between either pair of groups. Gatifloxacin ophthalmic gel was found to attain significantly higher concentrations than the ophthalmic solution in ocular tissues.

Quinolone immediate hypersensitivity due to topical ophthalmic preparations: a case report and review of literature

Ophthalmic quinolone preparations are widely used for the treatment of eye diseases; however, there are only a few reported cases of immediate hypersensitivity due to such medications. Here, we present a case of immediate hypersensitivity induced by an ophthalmic administration of quinolones in a 20-year-old female with bacterial conjunctivitis. The results of skin prick and basophil activation tests suggest that it involved a type Ib reaction associated with Mas-related G-protein coupled receptor X2. The present case cautions us to be aware of quinolone immediate hypersensitivity caused by topical ophthalmic preparations, which can easily be overlooked, because it may predict severe hypersensitivity reactions to systemic administration.

Antibacterial resistance in ophthalmic infections: a multi-centre analysis across UK care settings

BACKGROUND

Bacterial ophthalmic infections are common. Empirical treatment with topical broad-spectrum antibiotics is recommended for severe cases. Antimicrobial resistance (AMR) to agents used for bacterial ophthalmic infections make it increasingly important to consider changing resistance patterns when prescribing, however UK data in this area are lacking. We evaluate the epidemiology and antimicrobial susceptibilities of ophthalmic pathogens across care settings and compare these with local and national antimicrobial prescribing guidelines.

METHODS

A retrospective, multi-centre observational analysis was undertaken of ophthalmic microbiology isolates between 2009 and 2015 at a centralised North-West London laboratory (incorporating data from primary care and five London teaching hospitals). Data were analysed using descriptive statistics with respect to patient demographics, pathogen distribution (across age-groups and care setting), seasonality, and susceptibility to topical chloramphenicol, moxifloxacin, and fusidic acid.

RESULTS

Two thousand six hundred eighty-one isolates (n = 2168 patients) were identified. The commonest pathogen in adults was Staphylococcus spp. across primary, secondary, and tertiary care (51.7%; 43.4%; 33.6% respectively) and in children was Haemophilus spp. (34.6%;28.2%;36.6%). AMR was high and increased across care settings for chloramphenicol (11.8%;15.1%;33.8%); moxifloxacin (5.5%;7.6%;25.5%); and fusidic acid (49.6%;53.4%; 58.7%). Pseudomonas spp. was the commonest chloramphenicol-resistant pathogen across all care settings, whilst Haemophilus spp. was the commonest fusidic acid-resistant pathogen across primary and secondary care. More isolates were recorded in spring (31.6%) than any other season, mostly due to a significant rise in Haemophilus spp.

CONCLUSIONS

We find UK national and local antimicrobial prescribing policies for ophthalmic infections may not be concordant with the organisms and antimicrobial susceptibilities found in clinical samples. We also find variations in microbial incidence related to patient age, clinical setting, and season. Such variations may have further important implications for prescribing practices and modification of antimicrobial guidelines.

Chloramphenicol Resurrected: A Journey from Antibiotic Resistance in Eye Infections to Biofilm and Ocular Microbiota

The advent of multidrug resistance among pathogenic bacteria is devastating the worth of antibiotics and changing the way of their administration, as well as the approach to use new or old drugs. The crisis of antimicrobial resistance is also due to the unavailability of newer drugs, attributable to exigent regulatory requirements and reduced financial inducements. The emerging resistance to antibiotics worldwide has led to renewed interest in old drugs that have fallen into disuse because of toxic side effects. Thus, comprehensive efforts are needed to minimize the pace of resistance by studying emergent microorganisms and optimize the use of old antimicrobial agents able to maintain their profile of susceptibility. Chloramphenicol is experiencing its renaissance because it is widely used in the treatment and prevention of superficial eye infections due to its broad spectrum of activity and other useful antimicrobial peculiarities, such as the antibiofilm properties. Concerns have been raised in the past for the risk of aplastic anemia when chloramphenicol is given intravenously. Chloramphenicol seems suitable to be used as topical eye formulation for the limited rate of resistance compared to fluoroquinolones, for its scarce induction of bacterial resistance and antibiofilm activity, and for the hypothetical low impact on ocular microbiota disturbance. Further in-vitro and in vivo studies on pharmacodynamics properties of ocular formulation of chloramphenicol, as well as its real impact against biofilm and the ocular microbiota, need to be better addressed in the near future.

Clinical and Antibacterial Efficacy and Safety of Besifloxacin Ophthalmic Suspension Compared With Moxifloxacin Ophthalmic Solution

PURPOSE

To evaluate the efficacy of besifloxacin ophthalmic suspension 0.6% compared with moxifloxacin ophthalmic solution 0.5% in the treatment of bacterial conjunctivitis in an Indian population.

DESIGN

Multicenter, randomized, double-masked, active-controlled, parallel-group, clinical trial, including 6 clinical sites in India.

METHODS

Patients were randomized to receive 1 drop of besifloxacin or moxifloxacin in the infected eye(s), 3 times daily, for 5 days. Primary efficacy end points included clinical resolution and bacterial eradication at day 5. Secondary efficacy end points included clinical resolution and bacterial eradication at day 8, ocular discharge, bulbar conjunctival injection, investigator's global assessment, and bacterial eradication by species. Efficacy was analyzed using the Cochran-Mantel-Haenszel and Pearson χ2 tests. Safety was assessed by the incidence of ocular and nonocular treatment-emergent adverse events (AEs), changes in visual acuity, and biomicroscopy and ophthalmoscopy findings. Data presented are that for the subset of patients from India.

RESULTS

Of the 123 patients randomized at clinical sites in India, 96.7% completed the study. Day 5 differences in microbial eradication (100% besifloxacin vs 96.3% moxifloxacin) and in clinical resolution (78.9% besifloxacin vs 71.4% moxifloxacin) were not statistically significant. No statistically significant between-group differences were observed for secondary end points. All ocular AEs in both groups were mild or moderate in severity. There were no drug-related ocular AEs with besifloxacin.

CONCLUSIONS

Treatment of bacterial conjunctivitis with besifloxacin 0.6% produces similar antibacterial and clinical efficacy as that with moxifloxacin 0.5% in an Indian population, with no clinically meaningful safety concerns.

[Purulent corneal ulcers: clinical presentation, diagnosis, and conservative treatment]

This is a detailed review of purulent corneal ulcer signs and symptoms, problems in diagnosis, and conservative treatment options.

In vitro moxifloxacin drug interaction with chemotherapeutics: implications for retinoblastoma management

Retinoblastoma (RB) is a common malignant intraocular tumor primarily affecting children. Multidrug resistance (MDR) proteins (P-gp and MRPs) mediated chemoresistance have been considered as a major cause of treatment failure in treatment of RB. Ocular cells have shown good tolerability against moxifloxacin (MFX). Hence, the aim of present study was to investigate the effect of moxifloxacin on the functionality of MDR proteins. Furthermore, we have also examined an interaction of MFX with anticancer agents (Topotecan, etoposide and vinblastine) for RB treatment. For interaction of MFX with efflux transporter, model cell lines transfected with the efflux transporters (MDCK-MDR1 and MDCK-MRP2) were used to perform uptake and bi-directional transport experiments. Modulation of anticancer induced cell cytotoxicity, pro-inflammatory cytokines (IL-6 and IL-8) release and caspase-3 enzyme activity in presence of MFX was also evaluated. Result indicates that MFX is a substrate of both MDR1 and MRP2 efflux transporters. Furthermore elevation of anticancer uptake and bi-directional transport, reduction in IC50 cytotoxic value and modulation of antiproliferative and cytokines release in presence of MFX by anticancer agents was observed. Our results demonstrate that MFX may not only modulate the permeability of anticancer agents at efflux sites but it may also potentiate antiproliferative activity of anticancer agents in retinoblastoma cells. This study may be further extended to explore in vivo outcome of this finding.