Comparison of topical 0.3% ofloxacin with fortified tobramycin plus cefazolin in the treatment of bacterial keratitis

Safety and efficacy of fortified antibiotics and fluoroquinolones for the treatment of bacterial keratitis: A meta-analysis

PURPOSE

To compare the safety and efficacy of fortified antibiotics and fluoroquinolones in the treatment of bacterial keratitis.

METHODS

PubMed, EMBASE, Cochrane Library, CNKI, Wanfang database and VIP database were systematically searched for randomized controlled trials (RCT) of treatment of bacterial keratitis with fortified antibiotics and fluoroquinolones. Rev Man 5.3 software was used to analyze outcome index cure rate, time to cure, and adverse events in a meta-analysis.

RESULTS

After literature search and screening, 9 randomized controlled trials were included in this study. Compared with traditional fortified antibiotic therapy, fluoroquinolones show consistency in terms of cure rate and incidence of adverse events: cure rates (OR=0.99, 95% CI: 0.75, 1.30) and incidence of adverse events (OR=0.75, 95% CI: 0.48, 1.17). However, the time to cure for fluoroquinolones was shorter than that of fortified antibiotics (MD=0.96, 95% CI: 0.50, 1.41).

CONCLUSION

The cure rate and safety of fluoroquinolones are equivalent to those of fortified antibiotics, so it seems reasonable to use fluoroquinolones as the preferred treatment for bacterial keratitis.

Bacterial keratitis in a tertiary hospital in São Paulo: a 21-year review of the epidemiological, laboratory, and clinical data

Infectious keratitis is a sight-threatening condition that is usually an ocular emergency. The visual outcome depends on prompt and accurate clinical management as well as geographic and epidemiological awareness. We conducted a retrospective observational study to define the epidemiological and laboratory profile, as well as the clinical course of bacterial keratitis in a tertiary hospital in São Paulo over 21 years. Information about age, sex, predisposing factors, topical and surgical treatment, visual acuity, ulcers' classification, bacterioscopy, culture, and antibiotic sensitivity tests were collected. This study included 160 patients. The mean age was 65.1 ± 18.4 years and risk factors were identified in 83.1 % of the patients. Empirical topical fortified cephalosporin with an aminoglycoside or fourth-generation fluoroquinolone was curative for 66.2 % of the cases. The mean treatment duration was 22.5 ± 9 days. The mean variation of visual acuity was -0.25 logMAR, p < 0.001. Culture revealed 64 % of Gram-positive bacteria. All Gram-positive bacteria were sensitive to cephalothin, vancomycin, and quinolones. All Gram-negative bacteria were sensitive to gentamicin, tobramycin, amikacin, and ciprofloxacin. These findings reinforce the importance of prompt empirical treatment of severe corneal ulcers with a fortified cephalosporin and aminoglycoside or a fourth-generation fluoroquinolone as there are equally effective. Collected data was insufficient to evaluate resistance of ocular infections over time in this population.

The clinical treatment of bacterial keratitis: A review of drop instillation regimes

Bacterial keratitis (BK) presentations are often treated using the commercially available second-generation fluoroquinolones ciprofloxacin 0.3% and ofloxacin 0.3% as monotherapy. The guidelines available for instillation regimes are often not supported by data from clinical studies. This review examines the peer-reviewed clinical studies and compared treatment failure rates for ciprofloxacin 0.3% and ofloxacin 0.3% for BK in relation to Day-1 drop-regimes. From the statistical analysis, this review derived evidence-based clinically applicable minimum drop-regimes for the treatment of BK on Day-1. Lower numbers of drops of ciprofloxacin on Day-1 were significantly associated with increased treatment failure rates (p < 0.002). The derived minimum number of drops on Day for ciprofloxacin on Day-1 was 47 drops, and for ofloxacin 24 drops. The mean number of drops used in the clinical studies was significantly lower than the manufacturers' recommended Day-1 regimes for both ciprofloxacin (p = 0.0006) and ofloxacin (p = 0.048). From Day-3 to -6 of treatment the drop rates for ciprofloxacin relative to recommended rates were higher, and for ofloxacin lower (p = 0.014). The findings of this review were then compared with a representative sample of published guidelines and case studies to determine the validity of applying those drop-regimes in clinical practice. Although the manufacturers' suggested minimum drop-regimes on Day-1 were significantly different (120 drops ciprofloxacin, 34 drops ofloxacin, p < 0.0001), many of the published guidelines suggested the same drop-regime for both fluoroquinolones. The suggested drop numbers on Day-1 for ciprofloxacin in these guidelines and case studies were significantly less than those used in the clinical studies (p = 0.043). Increased treatment failure rates for ciprofloxacin are associated with lower drop numbers on Day-1. The Day-1 dosing rates for ciprofloxacin and ofloxacin should be considered separately, and the regimes suggested in published guidelines and case studies may need be re-considered in light of the findings of this review.

Melting corneal ulcers (keratomalacia) in dogs: A 5-year clinical and microbiological study (2014-2018)

OBJECTIVES

To identify bacterial microorganisms associated with canine keratomalacia, review their antimicrobial sensitivity, and evaluate clinical outcomes compared to results of microbial culture.

METHODS

Retrospective analysis of clinical records of dogs diagnosed with a melting corneal ulcer presented to a referral hospital in Hertfordshire, UK between 2014 and 2018.

RESULTS

One hundred and ten melting corneal ulcers were sampled in 106 dogs. The most common pure bacterial isolate was Pseudomonas aeruginosa (n = 26) followed by β-hemolytic Streptococcus (n = 12). Melting corneal ulcers that cultured coagulase-positive Staphylococcus, coliform bacteria, Pasteurella multocida, Enterococcus, and Streptococcus viridans presented in smaller numbers and were analyzed together (n = 16). Multiple cultures were identified in nine cases (n = 9). Forty-seven cultures yielded no bacterial growth (n = 47). The susceptibility to fluoroquinolones remained high with the exception of β-hemolytic Streptococci. There was no significant difference in the ulcer severity at presentation in regard to the cultured bacteria. Overall, 63 eyes (57%) received surgical grafting in addition to medical treatment. In 14 cases (13%), the progression of corneal melting despite medical ± surgical treatment resulted in enucleation. Fifty-seven percent (8/14) of the enucleated eyes cultured pure Pseudomonas aeruginosa isolates. In contrast, all β-hemolytic Streptococcus-associated ulcers healed.

CONCLUSIONS

The most common bacterial species associated with canine keratomalacia were Pseudomonas aeruginosa and β-hemolytic Streptococcus. Because of the variation in antibacterial sensitivity between these two species, bacterial culture and sensitivity testing should be performed in all dogs presenting with keratomalacia. Melting corneal ulcers associated with pure Pseudomonas infection were significantly more likely to result in globe loss than melting corneal ulcers associated with other cultures.

A New Treatment Experience in Pseudomonas Keratitis: Topical Meropenem and Cefepime

PURPOSE

To compare the efficacy of topical meropenem and cefepime treatments with respect to moxifloxacin as new treatment options in an experimental Pseudomonas keratitis model.

METHODS

Twenty-four rabbits in which keratitis are induced using Pseudomonas aeruginosa were divided into four groups according to treatment options. A solution of 50 mg/mL meropenem was prepared and topically applied to the first group, 50 mg/mL cefepime solution to the second group, topical 0.5% moxifloxacin drop to the third group, and topical isotonic (0.9% saline) solution to the fourth (control) group. The eyes were examined before and after treatment to score the clinical severity. After the subjects were sacrificed, their corneas were excised. To determine the efficacy of treatments, clinical score, bacterial load, and histopathological and immunohistochemical findings were evaluated.

RESULTS

When the three treatment groups were compared, there was a significant difference in the colony-forming unit (CFU) value, polymorph-nuclear leukocyte (PMNL) infiltration, and matrix metalloproteinase (MMP)-9 immunoreactivity (P=0.022, P=0.038, and P=0.037, respectively). The CFU values, PMNL infiltration scores and MMP-9 immunoreactivity were significantly lower in the meropenem and moxifloxacin groups compared with the cefepime group (P<0.05 for all). There was no significant difference between the meropenem and moxifloxacin groups in respect of the CFU values, PMNL infiltration, and MMP-9 immunoreactivity (P=0.842, P=0.784, and P=0.699, respectively).

CONCLUSION

The results of our study indicate that topical meropenem is at least as effective as topical moxifloxacin in the treatment of Pseudomonas keratitis. The meropenem and moxifloxacin are safer and suitable in the limited corneal invasion than cefepime. Thus, topical meropenem may be an alternative drug in the treatment of this condition. Clinical studies are needed to be conducted to assess this possibility more accurately.

Treatment of Severe Infectious Keratitis With Scleral Contact Lenses as a Reservoir of Moxifloxacin 0.5

PURPOSE

To report the outcomes of using scleral contact lenses as antibiotic reservoirs as a therapeutic approach in a case series of severe infectious keratitis and to discuss the clinical potential.

METHODS

This was a prospective consecutive case series study of 12 eyes treated for infectious keratitis at the "Conde de Valenciana" Institute of Ophthalmology. A scleral lens (SL) filled with 0.5% moxifloxacin was used as a reservoir and replaced every 24 hours until epithelization was complete or the culture report and/or antibiogram demonstrated either a microorganism not susceptible to or resistant to moxifloxacin.

RESULTS

The study included 12 eyes of 12 patients (7 women; 58.33%; average age of 63 ± 20.11 years). All patients completed at least 1 month of follow-up. Patients had a diagnosis of infectious keratitis, and the SL was fitted on initial consultation. Of the 12 eyes, 7 had culture-positive bacterial infection, 2 eyes were mycotic, and 3 eyes had no culture growth. In 3 eyes, SL was discontinued because of the lack of response (one eye) and to the presence of mycotic infection (2 eyes). All infections resolved favorably at the final follow-up.

CONCLUSIONS

The use of SLs could be an alternative for antibiotic impregnation and treatment of infectious keratitis. No complications or side effects were observed related to the use of the scleral contact lens as a reservoir for the antibiotic. This treatment modality could offer a comfortable treatment for the patient, ensuring good impregnation and maintenance of antibiotic concentrations during the 24-hour wear periods.

Bacterial Keratitis: Isolated Organisms and Antibiotic Resistance Patterns in San Francisco

PURPOSE

Understanding the spectrum of pathogens in a given geographic region is important when deciding on empiric antibiotic therapy. In this study, we evaluate the spectrum of bacterial organisms cultured from corneal samples and their antibiotic sensitivities to guide initial treatment of keratitis.

METHODS

We performed a retrospective case review of cultures from suspected infectious keratitis cases at the Francis I. Proctor Foundation, University of California, San Francisco, from 1996 through 2015. Logistic regression models were used to assess the risk of culturing methicillin-resistant Staphylococcus aureus (MRSA) from ulcers over time and the association between the year cultured and moxifloxacin resistance.

RESULTS

A total of 522 of 2203 (23.7%) cultures grew bacterial organisms believed to be the etiology of infection, with available antibiotic sensitivity data. Of these, 338 (65.3%) grew gram-positive organisms with the most common being methicillin-sensitive Staphylococcus aureus (20.1%, N = 105). One hundred eighty (34.7%) grew gram-negative species with Pseudomonas aeruginosa as the most prevalent organism (10.9%, N = 57). There was 1.13 increased odds of culturing MRSA for each 1-year increase in the culture date (P = 0.01) and 1.26 increased odds of culturing an organism resistant to moxifloxacin with each 1-year increase in the culture date after controlling for the infectious organism (P < 0.001).

CONCLUSIONS

Gram-positive organisms are the most commonly identified etiology of microbial keratitis in this series. Approximately 35% of cultured organisms had variable susceptibility to moxifloxacin, and resistance seems to be increasing over time. The risk of culturing MRSA increased over time.

Bacterial keratitis treated by strengthened antibiotic eye drops: An 18 months review of clinical cases and antibiotic susceptibilities

PURPOSE

To describe, in patients treated for infectious keratitis, the microorganisms identified and their antibiotic susceptibility over a period of 18 months.

METHOD

Retrospective, descriptive, non-comparative study. Medical and biological data were extracted from the patients' file treated with strengthened antibiotic eye drops at Angers University Hospital between January 2015 and June 2016. The main elements noted were the bacteria involved and their susceptibility to antibiotics. Patients' visual acuity at the start and end of treatment was compared.

RESULTS

Forty-eight patients were included. Almost one bacterium was identified in 31 patients, totalling 43 pathogens of 24 different species. The most frequently found microorganisms were Gram-positive cocci (55.8%), including Staphylococcus Aureus (14.0%) and Epidermidis (14.0%). All Gram-negative bacilli amounted to 30.2% of the identified bacteria, including 9.3% of Pseudomonas aeruginosa. None of the Gram-positive cocci were resistant to vancomycin and all Gram-negative bacilli were susceptible to ceftazidime and amikacin. Following treatment with at least one of the three antibiotic eye drops produced by our pharmacy (amikacin at 50mg/mL, ceftazidime at 50mg/mL and vancomycin at 25mg/mL), patients' visual acuity was significantly improved (P=0.043).

CONCLUSION

The study helped identify the bacterial ecology of patients admitted for infectious keratitis. Among the bacteria identified, none were found to be resistant to any of the three strengthened antibiotic eye drops produced by the hospital pharmacy. These eye drops allowed for a rapid and effective treatment of patients and the improvement of their visual acuity before even identifying the bacteria.

Update on the Management of Infectious Keratitis

Infectious keratitis is a major global cause of visual impairment and blindness, often affecting marginalized populations. Proper diagnosis of the causative organism is critical, and although culture remains the prevailing diagnostic tool, newer techniques such as in vivo confocal microscopy are helpful for diagnosing fungus and Acanthamoeba. Next-generation sequencing holds the potential for early and accurate diagnosis even for organisms that are difficult to culture by conventional methods. Topical antibiotics remain the best treatment for bacterial keratitis, and a recent review found all commonly prescribed topical antibiotics to be equally effective. However, outcomes remain poor secondary to corneal melting, scarring, and perforation. Adjuvant therapies aimed at reducing the immune response associated with keratitis include topical corticosteroids. The large, randomized, controlled Steroids for Corneal Ulcers Trial found that although steroids provided no significant improvement overall, they did seem beneficial for ulcers that were central, deep or large, non-Nocardia, or classically invasive Pseudomonas aeruginosa; for patients with low baseline vision; and when started early after the initiation of antibiotics. Fungal ulcers often have worse clinical outcomes than bacterial ulcers, with no new treatments since the 1960s when topical natamycin was introduced. The randomized controlled Mycotic Ulcer Treatment Trial (MUTT) I showed a benefit of topical natamycin over topical voriconazole for fungal ulcers, particularly among those caused by Fusarium. MUTT II showed that oral voriconazole did not improve outcomes overall, although there may have been some effect among Fusarium ulcers. Given an increase in nonserious adverse events, the authors concluded that they could not recommend oral voriconazole. Viral keratitis differs from bacterial and fungal cases in that it is often recurrent and is common in developed countries. The Herpetic Eye Disease Study (HEDS) I showed a significant benefit of topical corticosteroids and oral acyclovir for stromal keratitis. HEDS II showed that oral acyclovir decreased the recurrence of any type of herpes simplex virus keratitis by approximately half. Future strategies to reduce the morbidity associated with infectious keratitis are likely to be multidimensional, with adjuvant therapies aimed at modifying the immune response to infection holding the greatest potential to improve clinical outcomes.

The efficacy and safety of 0.5% Levofloxacin versus fortified Cefazolin and Amikacin ophthalmic solution for the treatment of suspected and culture-proven cases of infectious bacterial keratitis: a comparative study

Background: Bacterial keratitis is a major devastating ocular condition that quickly deteriorates the patient’s vision. Vigorous and prompt treatment of bacterial keratitis with broad-spectrum antibiotic eye-drops is preferred.

Objective: Evaluate the efficacy and safety of 0.5% Levofloxacin for the treatment of suspected and cultureproven cases of infectious bacterial keratitis in comparison to fortified Cefazolin and Amikacin ophthalmic solution.

Materials and methods: Seventy-one eyes from 69 patients suspected of having infectious bacterial keratitis were enrolled in the study. The patients were randomized into two arms, 0.5% Levofloxacin eye drops (34 eyes) or fortified Cefazolin and Amikacin (37 eyes). Sixty-eight eyes were included in the efficacy analysis. During treatment, on days 2, 7, 14, and 21, the patient’s symptoms and signs were scored from grade 0-3 (absent to severe).

Results: At the end of the treatment, 61 out of 71 eyes completely healed. The resolution of the keratitis was not significantly different between both groups. There were no significant differences in the mean time-duration for the ulcer to heal or for the symptoms and clinical signs to disappear between the two groups. No serious adverse events or side effects from the disease were found. The patients compliance was 80% based on the self-reported diaries.

Conclusion: The efficacy and safety of 0.5% topical Levofloxacin was comparable to fortified Cefazolin and Amikacin for the treatment of mild-to-moderate bacterial keratitis. Topical Levofloxacin is far superior because of its availability and patient compliance when used as monotherapy for the treatment of infectious bacterial keratitis.

Various factors affecting the bacterial corneal ulcer healing: a 4-years study in referral tertiary eye hospital in Indonesia

Background: Corneal ulcer is one of the most common causes of visual acuity impairment and blindness all over the world. The aim of the study was to evaluate various factors affecting the bacterial corneal ulcers healing, including the predisposing factors, causative organisms, antibiotic sensitivity, as well as the treatment outcomes.Methods: All data were taken retrospectively from medical records of patients who underwent corneal scraping for Gram examination and/or culture over a-4-year period (2008-2011) at the Cipto Mangunkusumo Hospital Jakarta. Treatment outcome were analyzed using Chi-square test, one-way ANOVA, and post-hoc analysis. Mean time required for complete epithelial healing was also investigated.Results: 220 cases of bacterial corneal ulcers in 216 patients were included. The most common risk factors were ocular trauma (45.8%). Gram-positive coccus were found in 65.7% cases other than other microbes. Pseudomonas sp. (25,0%) and Staphylococcus epidermidis (18.4%) were the most common isolates, sensitive to almost all kinds of antibiotics. About 83.0% (106 cases) were improved with antibiotics only, the rest were not improved and worsened. Mean time for complete epithelial healing was 17.5 ± 8.9 days with mild ulcer had the most rapid recovery. Eyes treated with fluoroquinolone eyedrops were healed in 14 days, faster than other regiments.Conclusion: Ocular trauma was the most common risk factor for corneal ulcer, and the most commonly isolated organism was Pseudomonas sp. Most cases were improved with antibiotics, and fluoroquinolone showed faster healing. Complete epithelial healing occurred in about 17.5 days.

Levofloxacin and Tobramycin for Severe Bacterial Keratouveitis

PURPOSE

To report on clinical features and outcome of severe bacterial keratouveitis.

METHODS

Twenty patients with severe bacterial keratouveitis treated with topical tobramycin and levofloxacin and oral levofloxacin were included. Main outcome measures were ulcers location, bacterial isolates, risk factors, visual prognosis.

RESULTS

Centrally located ulcer/abscess was present in 65% of patients. Contact lens (CL) wear was the most common risk factor (70%). Bacterial isolates were observed in 58% of patients, none resistant to tobramycin and levofloxacin. Pseudomonas aeruginosa was found in 47% of positive cases and in 64% of CL wearers. After therapy, the mean visual acuity improved significantly (p < 0.0001), particularly in contact lens wearers (p = 0.04) and in patients younger than 60 years old (p < 0.001).

CONCLUSIONS

Pseudomonas aeruginosa is the most frequent cause of bacterial keratouveitis and CL wear the most common risk factor. Topical tobramycin and levofloxacin and oral levofloxacin are effective in the treatment of bacterial keratouveitis.

Community opinions in the management of corneal ulcers and ophthalmic antibiotics: a survey of 4 states

OBJECTIVE

To evaluate the ophthalmic community's current opinions of the management of bacterial keratitis and usage of the currently available ophthalmic antibiotics.

METHODS

An anonymous questionnaire was mailed to ophthalmologists in California, Florida, Illinois, and Missouri. The results were tabulated and analyzed statistically.

RESULTS

Six hundred twenty-nine usable questionnaires (10.3%) were returned. In the management of corneal ulcers, 42.2% of comprehensive ophthalmologists and 75.3% of cornea specialists perform Gram stains some of the time. A total of 73.3% of comprehensive ophthalmologists and 93.7% of cornea specialists perform corneal cultures some of the time. A total of 88.8% of comprehensive ophthalmologists and 76% of cornea specialists initiate treatment with the newer fluoroquinolone antibiotics. A total of 12.1% of comprehensive ophthalmologists and 41% of cornea specialists would select fortified antibiotics for the treatment of corneal ulcers. The percentage of those who feel that fortified antibiotics are superior ranges from 17.7% for comprehensive ophthalmologists to 33.3% for cornea specialists. A total of 65.7% of comprehensive ophthalmologists indicate that the newer fluoroquinolones have impacted their practices, and 58.3% indicate that they represent an improvement over older fluoroquinolones.

CONCLUSIONS

Most responding ophthalmologists initiate empiric therapy with the newer fluoroquinolone antibiotics for corneal ulcers, forgoing Gram staining and culturing. However, respondents are not universally sanguine about the newer fluoroquinolones. The practice patterns and opinions on antibiotics differ almost universally between comprehensive ophthalmologists and cornea specialists. Larger, more detailed surveys and more specific analyses would help to further establish the factors that lead to differing management choices and opinions.

Trends in fungal keratitis in the United States, 2001 to 2007

OBJECTIVE

Fungal keratitis is a serious ocular infection that is considered to be rare among contact lens wearers. The recent Fusarium keratitis outbreak raised questions regarding the background rate of Fusarium-related keratitis and other fungal keratitis in this population.

DESIGN

Retrospective, multicenter case series.

PARTICIPANTS

Six hundred ninety-five cases of fungal keratitis cases who presented to 1 of 10 tertiary medical centers from 2001 to 2007.

METHODS

Ten tertiary care centers in the United States performed a retrospective review of culture-positive fungal keratitis cases at their centers between January 2001 and December 2007. Cases were identified using microbiology, pathology, and/or confocal microscopy records. Information was collected on contact lens status, method of diagnosis, and organism(s) identified. The quarterly number of cases by contact lens status was calculated and Poisson regression was used to evaluate presence of trends. The Johns Hopkins Medicine Institutional Review Board (IRB) and the IRBs at each participating center approved the research.

MAIN OUTCOME MEASURES

Quarterly number of fungal keratitis cases and fungal species.

RESULTS

We identified 695 fungal keratitis cases; 283 involved the use of contact lenses. The quarterly number of Fusarium cases increased among contact lens wearers (CLWs) during the period that ReNu with MoistureLoc (Bausch & Lomb, Rochester, NY) was on the market, but returned to prior levels after withdrawal of the product from the market. The quarterly frequency of other filamentous fungi cases showed a statistically significant increase among CLWs comparing October 2004 through June 2006 with July 2006 through December 2007 with January 2001 through September 2004 (P < 0.0001).

CONCLUSIONS

The quarterly number of Fusarium fungal keratitis cases among CLWs returned to pre-Renu with Moistureloc levels after removal of the product from the market. However, the number of other filamentous fungal keratitis cases, although small, seems to have increased among refractive CLWs. Reasons for these apparent increases are unclear.

[Fluoroquinolones in ophthalmology: indications and current use]

Fluoroquinolones are commonly used in ophthalmology, either for conjunctival infections or endophthalmitis. Use of these antibiotics requires good knowledge of the pharmacokinetic profile and adverse effects, and contraindications must be respected. Fluoroquinolones are useful in 2008 given their antibacterial spectrum, good ocular penetration, and the potential benefit of intravitreal injection.

Medical management approach to infectious keratitis

This section provides guidelines on medical therapy of patients with infectious keratitis. In addition to initial empirical therapy, preferred medications, once the organisms responsible are isolated, are discussed. Atypical mycobacterial keratitis following lasik is described. General guidelines for supportive therapy and follow-up, of these patients are presented. Clinical response to treatment and indications for intervention are discussed. Possible causes and approach to cases refractory to medical therapy are discussed.

Prescrire les collyres fortifiés

Fortified preparations of ophthalmic antibiotics are made with commercially available antibiotics (parenteral or lyophilized preparations). These fortified eyedrops have two main advantages: the increase in the antibiotic concentration in the corneal stroma and the wide choice of available antibiotics. Fortified ophthalmic solutions are used in severe keratitis (large diameter, stroma infiltration, inflammation of the anterior chamber, old patient). The following associations are recommended: ticarcillin+gentamicin+vancomycin or cephazolin+amikacin since they provide a broad-spectrum antibiotic activity against the wide range of bacteria that may cause keratitis. The main toxicity of these preparations is the retardation effect of the epithelial-healing rate (aminoglycosides, vancomycin) and the corneal and conjunctival toxic effects (aminoglycosides). However, fortified antibiotic drops remain the standard therapy for severe bacterial keratitis, given their corneal penetration and the possibility of the synergic and combined effect of an antibiotic association.

Demographic pattern, predisposing factors and management of ulcerative keratitis: evaluation of one thousand unilateral cases at a tertiary care centre

PURPOSE

To determine the predisposing factors, special clinical manifestations and the management of presumed microbial ulcerative keratitis.

METHODS

A retrospective study was performed in 1000 eyes of 1000 patients with presumed microbial keratitis. Information was recorded on patients' age and gender, risk factors, seasonal presentation, number of days since initiation of ulcer, prior therapy, clinical presentation, microbiological work-up and case management.

RESULTS

Fifty per cent of the patients with corneal ulcers were aged between 36 and 65 years and 13.3% were in the paediatric age group (1 month to <16 years). The male : female ratio was almost 1.6:1. Only 11.4% of patients reported to the authors during the first week of initiation of ulcer. Trauma was the cause in 47.6% of eyes, and ocular surface diseases accounted for 16.6%. Forty-two per cent of eyes received topical antibiotics alone (either one or more) prior to hospital visit and 42.2% of eyes were on topical antibiotics and antifungals. Another 8.2% were on topical corticosteroids along with antibiotics and 4.6% were receiving some unidentified drop. Only 3% of the eyes did not receive any therapy prior to visit. Contact lens use as a risk factor could be identified only in 8.2% of eyes. Ulcers were central in location in 48%. Ulcer size 6-9 mm was observed in 51.7% of eyes. Medical therapy alone was effective in 61.0% of eyes and another 9.7% eyes responded to paramedian tarsorrhaphy along with topical antimicroboial drugs.

CONCLUSION

Corneal ulcers are a frequent problem in this part of the world. The ulcers seen at this tertiary referral hospital present late in the natural history of the disease and are clinically severe. Despite the severity a majority of the eyes could be saved anatomically, but almost 65% of eyes were left with a visual acuity of <6/120. Considering the high magnitude of visual loss, public education about the potential for loss of sight and the importance of timely and appropriate treatment is recommended.

Concentrations of levofloxacin, ofloxacin, and ciprofloxacin in human corneal stromal tissue and aqueous humor after topical administration

OBJECTIVE

To evaluate the penetration of commercially available levofloxacin 0.5%, ofloxacin 0.3%, and ciprofloxacin 0.3% topical ophthalmic solutions in human corneal stromal and aqueous humor tissues.

METHODS

A total of 67 patients scheduled to undergo penetrating keratoplasty for treatment of stromal scar or dystrophy, keratoconus, pellucid marginal degeneration, or endothelial disease were enrolled in this prospective, double-blind, 3-center study. To be considered for inclusion, patients had to have an intact corneal epithelium and minimal or no corneal edema (pachymetry < 650 microm). After informed consent was obtained, patients were randomized to receive 1 drop of levofloxacin 0.5%, ofloxacin 0.3%, or ciprofloxacin 0.3% topical ophthalmic solution at approximately 15 and 10 minutes before surgery. Approximately 0.1 mL of aqueous fluid was aspirated by paracentesis through the trephination wound at the onset of surgery, followed by excision of the affected cornea and removal of its epithelium. Specimens were stored frozen at -70 degrees C until assayed by high-performance liquid chromatography.

RESULTS

All 3 fluoroquinolones were well tolerated. A total of 65 corneas and 59 aqueous fluid samples were obtained and assayed. The mean +/- standard deviation corneal concentrations of ciprofloxacin, ofloxacin, and levofloxacin following a 2-drop administration were 9.92 +/- 10.99 microg/g (n = 18), 10.77 +/- 5.90 microg/g (n = 23), and 18.23 +/- 20.51 microg/g (n = 24), respectively. Although corneal stromal levels were highest in the levofloxacin group, the high degree of interpatient variability prevented demonstration of statistically significant differences when compared with ofloxacin (P = 0.377). In contrast, levofloxacin concentrations were approximately twice as high as ciprofloxacin, and this difference reached statistical significance (P = 0.014). The corresponding aqueous humor concentrations of ciprofloxacin, ofloxacin, and levofloxacin were 0.135 +/- 0.231 microg/mL (n = 15), 0.135 +/- 0.111 microg/mL (n = 20), and 0.372 +/- 0.546 microg/mL (n = 24, P < 0.001 versus ciprofloxacin and ofloxacin).

CONCLUSION

The topical administration of all 3 agents was well tolerated in patients undergoing penetrating keratoplasty. Two drops of levofloxacin 0.5% solution results in a 1.7- to 2.7-fold greater penetration into human corneal stromal and aqueous humor tissues than ofloxacin 0.3% or ciprofloxacin 0.3%. The mean intracorneal concentrations of all three agents following 2 drops exceeds the MIC90 for the majority of pathogens causing bacterial keratitis. Topical levofloxacin appears to offer pharmacokinetic and pharmacodynamic advantages over ofloxacin and ciprofloxacin in terms of enhanced transcorneal penetration; however, clinical comparative trials are needed to confirm these relative advantages.

Prescribing trends in infectious keratitis: a survey of New Zealand ophthalmologists

PURPOSE

To obtain an overview of the treatment of infectious diseases of the cornea by New Zealand ophthalmologists and to analyse the data in the context of evidence-based treatment recommendations.

METHODS

A questionnaire was sent to all New Zealand ophthalmologists. It comprised 23 multiple-choice questions pertaining to the characteristics of the respondents, the nature of their practice and their prescribing preferences in infectious conjunctivitis and keratitis.

RESULTS

Of the 93 ophthalmologists surveyed, 80.6% returned the questionnaire. Of those in clinical practice, 91.4% regularly treated patients with corneal disease. A subspecialty interest in cornea was stated by 12.5% of these. This paper reports observations for adenoviral conjunctivitis and adenoviral, Herpes simplex, varicella zoster, bacterial, acanthamoebal and fungal keratitis. In some conditions prescribing practice varied dramatically, such as in adenoviral conjunctivitis where 50% of respondents prescribed a corticosteroid and 51.6% an antibiotic, whereas 37.5% prescribed only lubrication or no topical treatment. In other conditions there was a high degree of agreement between ophthalmologists; indeed, all ophthalmologists treated Herpes simplex dendritic keratitis with topical acyclovir. No statistically significant differences in prescribing habits were identified between subspecialist and non-subspecialist groups, although some important clinical differences emerged. There were occasional marked differences in response when the age group of respondents was considered, particularly in relation to the management of adenoviral infections and bacterial keratitis.

CONCLUSIONS

The findings of this survey suggest that the majority of New Zealand ophthalmologists generally follow international guidelines for the management of infectious keratitis. The identified variations in management provide a foundation for informed clinical debate and the development of treatment guidelines, in line with evidence-based recommendations.

Clinical and epidemiological advantages of culturing bacterial keratitis

PURPOSE

To examine how the corneal culture result is associated with the antibacterial treatment response rate of ulcerative keratitis in a prospective cohort study and to determine whether culture confirmation affects the relative treatment effect in randomized clinical trials of bacterial keratitis.

METHODS

The influence of a positive bacterial culture on the rates of antibacterial improvement and cure was estimated by proportional hazards regression among 608 patients with ulcerative keratitis treated with topical ciprofloxacin monotherapy. The interaction of culture confirmation on the relative cure rates of 735 patients enrolled in 4 clinical trials comparing fluoroquinolone monotherapy to combined cephalosporin and aminoglycoside therapy was evaluated by metaregression.

RESULTS

In a prospective cohort study, bacterial keratitis that was culture positive and longer than 4 mm had a 37% (95% confidence interval, 20%, 51%) slower improvement rate and a 56% (95% confidence interval, 41%, 67%) slower cure rate during ciprofloxacin therapy. Among randomized clinical trials, the culture result did not modify the relative effect of treatments having similar 1-week cure rates.

CONCLUSIONS

Culture confirmation affects the antibacterial therapeutic response rate of ulcerative keratitis and, while not modifying the comparative effect of equivalent antibacterial treatments, facilitates generalizability of clinical trials of bacterial keratitis.

The efficacy and safety of topical polymyxin B, neomycin and gramicidin for treatment of presumed bacterial corneal ulceration

AIM

To evaluate the clinical efficacy and safety of topical polymyxin B, neomycin, and gramicidin for the treatment of suspected bacterial corneal ulceration at the Leiden University Medical Center.

METHODS

Patients with a diagnosis of a suspected bacterial corneal ulcer between April 1995 and February 2002 were retrospectively identified and reviewed; clinical and microbiological features and response to therapy were analysed. All patients were treated with Polyspectran eye drops.

RESULTS

In total, 91 patients were included in this analysis. Bacteriological cultures of 46 patients (51%) were positive and revealed 51 microorganisms. Staphylococcus aureus (29.4%) and Pseudomonas aeruginosa (23.5%) were the most frequently encountered bacteria. Eighteen patients switched therapy before complete healing of the corneal ulceration, four patients were lost to follow up. Of the 69 patients who completed Polyspectran treatment, re-epithelialisation occurred in 68 patients (99%) and on average took 12.6 (median 8) days. Among 91 patients, there were four perforations and one evisceration. Seven toxic or allergic reactions were reported.

CONCLUSION

This study shows that the combination of polymyxin B, neomycin, and gramicidin is an effective and safe treatment of suspected corneal ulceration.