Therapeutic possibilities of ceftazidime nanoparticles in devastating pseudomonas ophthalmic infections; keratitis and endophthalmitis

As the number of contact-lens wearers rises worldwide, Pseudomonas aeruginosa (PA) keratitis is attracting more attention as a major public health issue. Corneal lesions of PA, being the most intimidating complication of contact-lens wearer, can progress rapidly in spite of local antibiotic treatment, and may result in perforation and the permanent loss of vision. One of the explanations proposed for the evasion of the pathogen from immune responses of the host as well as antibacterial treatment is the fact that invasive clinical isolates of PA have the unusual ability to invade and replicate within surface corneal epithelial cells. In this manner, PA is left with an intracellular sanctuary. Endophthalmitis, albeit rare, is another ophthalmic infection faced by the challenge of drug delivery that can be potentially catastrophic. The present hypothesis is that nanoparticles can carry anti-pseudomonas antibiotics (e.g. ceftazidime) through the membranes, into the "hidden zone" of the pathogen, hence being an effective and potent therapeutic approach against pseudomonas keratitis and endophthalmitis.

Development of EKC after eximer laser photorefractive surgery and subsequent recurrence of EKC-like keratitis

This research focuses on four cases of patients having undergone eximer laser photorefractive surgery who were diagnosed with adenoviral keratoconjunctivitis during the postoperative period and who later developed epidemic keratoconjunctivitis (EKC)-like keratitis. Two of the patients had undergone laser-assisted subepithelial keratectomy (LASEK), one had undergone laser in situ keratomileusis and one had photorefractive keratectomy. After the surgery adenoviral keratoconjunctivitis and recurrent late-developing EKC-like keratitis were observed in the patients. Recurrent late-developing EKC-like keratitis occurred in one of the patients, who had received LASEK as many as three times. The others had only one or two episodes.The corneal infiltrates of keratitis mainly occurred in the central cornea. Successful resolution of recurrent late-developing EKC-like keratitis was achieved through the use of topical steroids without sequelae and the final best-corrected visual acuity was as good as the base line. These keratitis infiltrates have been presumed to represent an immune response to the suspected adenoviral antigens deposited in corneal stroma during the primary adenoviral infection. Previous reports argued that patients with a history of adenoviral ketatoconjunctivitis were succeptible to adenoviral keratoconjunctivitis becoming reactivated; however, in our research, our patients had their first adenoviral infections after the eximer laser photorefractive surgery and reactivation was confirmed. We recommend that attention be paid to adenoviral infection after laser refractive operations, because these patients seem to have more frequent recurrences.

Tarantula hairs as corneal foreign bodies

Purpose

To report a case of tarantula hairs found in the cornea and discuss treatment.

Case Report

A 16-year-old male presented with a 6-week history of right ocular irritation that began after letting his pet tarantula crawl on his face. Slit-lamp examination of the right eye revealed the presence of approximately 16 dark foreign bodies that had the appearance of small hairs. The foreign bodies were removed from the nasal region of the right cornea using Jewelers forceps, and the patient was prescribed a combination neomycin, polymyxin B, and dexamethasone ointment (Maxitrol^®), given 4 times per day.

Results

The patient presented for follow-up 2 weeks later, with resolution of symptoms.

Conclusion

Effective treatment of keratitis caused by tarantula hairs includes taking a detailed history, conducting a careful slit-lamp examination, removal of any accessible hairs, and initiation of treatment with a topical steroid as determined by the clinical picture.

Radial keratoneuritis as a presenting sign in acanthamoeba keratitis

The visual outcomes of Acanthamoeba keratitis, a rare cause of corneal infection, can be devastating. This paper reports two contact lens wearers with severe pain and photophobia who presented to the emergency room. Biomicroscopy revealed radial keratoneuritis in both individuals. Tissue culture on a nonnutrient agar plate with Escherichia coli overlay resulted in a heavy growth of Acanthamoeba. The inpatient treatment included 0.02% polyhexamethylene biguanide, chlorhexidine, neomycin/polymyxin B/bacitracin (Neosporin), and oral fluconazole, which successfully controlled the corneal infection and improvement in the best corrected visual acuity in both patients. Infection did not recur during the 12-month follow-up period. Acanthamoeba keratitis can present as radial keratoneuritis, mimicking other common corneal infections resulting in diagnostic and treatment delays. Early diagnosis and prudent treatment of Acanthamoeba keratitis are the keys to restoring vision and avoiding the subsequent need for penetrating keratoplasty.

Antibiotic susceptibility patterns of pseudomonas corneal ulcers in contact lens wearers

PURPOSE

To evaluate the resistance or susceptibility of Pseudomonas aeruginosa, the most common pathogen in contact lens keratitis and corneal ulcer, to different antibiotic regimens.

MATERIALS AND METHODS

This cross-sectional study included all patients with recently diagnosed contact lens corneal ulcer whose culture results were positive for P. aeruginosa, from March 2009 to March 2010. The empirical antibiotic therapy was changed to appropriate antibiotics according to the culture results, provided that satisfactory clinical improvement was not achieved with the initial antibiotic regimen. The overall sensitivity or resistance of P. aeruginosa to the most commonly used antibiotics was assessed based on the results of the antibiograms.

RESULTS

Fifty-two patients (43 females and 9 males) were included. Forty-five patients (86%) were wearing cosmetic contact lenses, while 7 patients (14%) were using therapeutic contact lenses. Thirty-nine patients (75%) were hospitalized and13 patients (25%) were followed up through an outpatient clinic. Thirty patients (58%) had central ulcers, whereas 22 patients (42%) had peripheral ulcers. Twelve patients (23%) had hypopyon in their first exam. The mean time to diagnose the ulcer after the last time wearing was 2 days (range: 12 hours to 5 days). AMT was required for 10 patients (19%). Based on the antibiograms, PA was shown to be sensitive in 100% of cases to ceftazidime and ciprofloxacin. Amikacin, imipenem, and gentamicin were the second most effective antibiotics.

CONCLUSION

P. aeruginosa was highly sensitive to ceftazidime, ciprofloxacin, and amikacin. All cases were resistant to cefazolin. Resistance to multiple antibiotics might be a significant concern in patients with corneal ulcers. In referral centers dealing with corneal ulcers, the initial antibiotic regimens should be changed from time to time to prevent this phenomenon.

A case of Stenotrophomonas maltophilia keratitis effectively treated with moxifloxacin

A 70-year-old man with a long history of diabetes mellitus presented to our hospital (Department of Ophthalmology, Sahm Yook Medical Center, Seoul, Korea) complaining of severe ocular pain and visual disturbance in his left eye that had started three days prior to admission. A round 3.7 × 5.0 mm dense central stromal infiltrate with an overlying epithelial defect was noted on slit-lamp examination. Following corneal scrapings and culture, topical 0.5% moxifloxacin and 0.5% tobramycin were administered hourly. A few days later, Stenotrophomonas maltophilia was isolated in a bacterial culture from a corneal specimen. According to the results of susceptibility tests, topical 0.5% moxifloxacin was given every hour and 0.5% tobramycin was stopped. The patient's clinical features improved steadily with treatment. The corneal epithelium healed rapidly, and the infiltrate resolved within four weeks of the initiation of treatment. The patient's best corrected visual acuity improved from hand motion to 20 / 25.

Evaluation of molecular diagnosis in fungal keratitis. Ten years of experience

Purpose

The aims of this study were to assess the utility of polymerase chain reaction (PCR) in diagnosing fungal keratitis in the last decade in our center and to review the molecular diagnosis of mycotic keratitis.

Methods

A retrospective nonrandomized investigation was undertaken at Vissum Corporación Instituto Oftalmologico de Alicante to evaluate 27 corneal samples of 20 patients with proven fungal keratitis from January 2000 to December 2009. Corneal samples (21 corneal scrapings, 5 biopsies, and 1 cornea) were evaluated by Gram stain or calcofluor stain, culture, and PCR. The detection and molecular identification were carried out by DNA amplification and sequencing of the internal transcribed spacer and 5.8S rRNA region from the corneal samples.

Results

PCR detected all the samples that were positive by conventional methods. Four samples were positive by PCR and showed negative results by culture and stain. Combination of microscopy and culture gave positive results in 21 of the 27 samples of patients with mycotic keratitis. Stains showed a 66.7% of positive results, culture showed 59.3%, and PCR showed 92.6%. The time taken for PCR assay was 4 to 8 h whereas positive fungal cultures took 1 to 35 days. Identification at species level by molecular methods was possible in all cases except one. Identification at species level by conventional methods only was possible in eight cases.

Conclusions

PCR not only proved to be an effective rapid method for the diagnosis of fungal keratitis but was also more sensitive than stain and culture methods. Fungal PCR must be added as the screening diagnosis test when an early mycotic keratitis is suspected. Molecular identification is the gold standard technique for the identification of corneal fungal pathogens.

Microbial keratitis in kingdom of bahrain: clinical and microbiology study

Background:

Microbial keratitis is a potentially vision threatening condition worldwide. Knowing the predisposing factors and etiologic microorganism can help control and prevent this problem. This is the first study of its kind in Kingdom of Bahrain.

Objective:

To study the profile of microbial keratitis in Bahrain with special focus on risk factors, clinical outcome and microbilogical results.

Methods:

A retrospective analysis of all patients admitted in Salmaniya Medical Complex over a period of three years from January 2005 to January 2007 was performed. A total of 285 patients with keratitis were analysed. Non infectious corneal ulceration were excluded. Data collected from medical records were demographic features, predisposing factors, history of corneal trauma, associated ocular conditions, visual acuity at the time of presentation and the clinical course. Predisposing risk factors measured were contact lens use, presence of blepharitis, diabetes, lid abnormalities, dry eyes, keratoplasty and refractive surgery. For contact lens wearers any contact lens related risk factors that can lead to keratitis were measured. Pearson's chi-square test was used to carry out statistical analysis wherever required.

Results:

Contact lens wear, as a risk factor for microbial keratitis, formed 40% of the total study population. Other risk factors identified were dry eyes 24 cases (8%), 10 blepharitis (3%), 22 trauma (8%), abnormal lid position 14 cases (5%). 6 patients keratitis in a graft (2%), 3 had refractive surgery (1%). The most common causative organism isolated was pseudomonas aeroginosa (54%) followed by streptococcus 12%, staph 10%, other organisms 6%. 95% of contact lens wearers had pseudomonas Aeroginosa. This was statistically significant (p< 0.0001). The vast majority, 92% healed with scarring. 1% needed therapeutic keratoplasty and 7% lost to follow up. Risk factors in contact lens wearers were; 41 patients (36%) slept with the contact lenses. 12 (8%) had contact lens related trauma and 8 (7%) had poor hygiene. Sleeping with the contact lenses was statistically significant (p< 0.0001).

Conclusion & Recommendation:

Contact lens wear is the major risk factor for microbial keratitis in Bahrain. Pseudomonas aeroginosa was the commonest bacteria isolated. Sleeping with the contact lenses is the major risk factor among contact lens wearers. Majority of keratitis patients resulted in permanent scarring on the cornea. Educating the public, especially on contact lens care and precaution, can help reduce this visual morbidity.

Bacterial keratitis: perspective on epidemiology, clinico-pathogenesis, diagnosis and treatment

Bacterial keratitis is an acute or chronic, transient or recurrent infection of the cornea with varying predilection for anatomical and topographical parts of the cornea like marginal or central. It is a potentially sight-threatening corneal infection in humans that is generally found in eyes with predisposing elements, the most common of which is contact lens wear. The epidemiological data reveals the universal occurrence of this disease. With advances in the understanding of its pathogenesis, laboratory investigations like immunohistochemistry, fluorescent microscopy, enzyme immunoassays and molecular biology, and the availability of fourth generation antibiotics, the overall visual outcome in bacterial keratitis has improved with time. Particular attention should be given to this condition as it can progress very rapidly with complete corneal destruction occurring within 24-48 hours. Early diagnosis, which is primarily clinical and substantiated largely by microbiological data, and prompt treatment are needed to minimise the possibility of permanent visual loss and reduce structural damage to the cornea.

A retrospective study of fungal corneal ulcers in the South sharqiyah region in oman

OBJECTIVES

To study the incidence, identify the risk factors and determine the predominant microorganisms and treatment regimen of fungal corneal ulcers.

METHODS

This was a retrospective analysis of corneal ulcers treated in the Ophthalmology Department of Sur Hospital, Oman, undertaken from January 2004 to December 2007. Medical and microbiology records of thirty two culture proven cases of fungal keratitis were reviewed for risk factors, laboratory findings and response to treatment.

RESULTS

Out of the total 242 corneal ulcers, 13.22 % were fungal. Among the 102 culture positive cases, 31.38 % were fungal isolates. Fusarium spp (50%) and Aspergillus spp (34.4%) predominated in the hyaline fungal spectrum. The important risk factors were topical steroid usage in 31.25 % of cases and ocular injury in 25 %. The majority of cases (90.62%) responded to 2% ketoconazole alone or in combination with 0.15% amphotericin B.

CONCLUSION

Fungal ulcer remains one of the leading causes of visual disability. Indiscriminate use of topical steroids and ocular trauma are the most important risk factors. Filamentous fungi are common aetiological agents in this region. Topical ketoconazole and amphotericin B were very effective for most of the cases.

A case of amniotic membrane transplantation in non-healing Nocardia asteroides keratitis

A patient with severe non-healing microscopically proven Nocardia keratitis was treated with maximal topical amikacin followed by amniotic membrane transplantation (AMT) 2 months later (single-layer epithelial side-down). Epithelial healing was achieved, but neovascularization continued. This case report indicates that AMT combined with topical antibiotic provides pain relief and allows epithelial healing in severe Nocardia keratitis.

Topical and oral voriconazole in the treatment of fungal keratitis

We describe two patients with fungal keratitis refractory to standard antifungal therapy whose conditions were managed with voriconazole. The first case is a patient with endophthalmitis and corneal ulcer due to Candida parapsilosis after receiving a corneal transplant. The patient was treated with amphotericin but showed no signs of improvement. Topical voriconazole, oral voriconazole, and intravitreal voriconazole yielded signs of improvement. The second case is a 63-year-old male who underwent a month of empiric treatment with 0.2% topical amphotericin for fungal keratitis but showed no signs of improvement. Treatment was then provided with 1% voriconazole. Both cases showed effective treatment with voriconazole. Voriconazole may be considered as a new method to treat fungal keratitis refractory to standard antifungal therapy.

Acanthamoeba species Keratitis in a Soft Contact Lens Wearer Molecularly Linked to Well Water

Acanthamoeba species keratitis has been associated with soft contact lens wear. In the present report, an epidemiological link was established between the patient's isolate and well water from the home using molecular methods. To the authors' knowledge, this is the first case in Canada where such a link has been established. Primary care practitioners and specialists, including ophthalmologists and infectious diseases specialists, must maintain a high degree of clinical suspicion in soft contact lens wearers with keratitis unresponsive to conventional topical and systemic treatment.

MYCOTIC KERATITIS

Mycotic keratitis is a distressing infection and may lead to permanent blindness. Fifty two cases of suspected mycotic keratitis were studied from Jan 91 to Sep 94. Specimens were collected on swabs in 20 cases and by corneal scraping in 32 cases. Wet mount examination of the specimens revealed fungal elements in 8 (15.4%) cases, of which 3 specimens were collected on swabs and 5 by corneal scraping. Fungi were isolated from a total of 12 (23.1%) specimens 5 of which were obtained by swabs while 7 by corneal scraping. Important pathogens were Fusarium spp, Aspergillus spp, Candida albicans and Cephalosporium spp. Direct examination of the specimens was found to be less sensitive than culture for the diagnosis of mycotic keratitis.