Methods for In Vivo/Ex Vivo Analysis of Antimicrobial Peptides in Bacterial Keratitis: siRNA Knockdown, Colony Counts, Myeloperoxidase, Immunostaining, and RT-PCR Assays

Antimicrobial peptides (AMPs) are essential components of the innate immune response. They have direct killing ability as well as immunomodulatory functions. Here, we describe techniques to identify specific AMPs involved in the protection against microbial keratitis, a vision threatening infection of the cornea of the eye which is the most serious complication of contact lens wear. Specifically we detail the use of siRNA technology to temporarily knockdown AMP expression at the murine ocular surface in vivo and then describe ex vivo assays to determine the level of bacteria, relative number of neutrophils, and levels of cytokines, chemokines, and AMPs in infected corneas.

Label-free electrical sensing of bacteria in eye wash samples: A step towards point-of-care detection of pathogens in patients with infectious keratitis

The diagnosis of keratitis is based on visual exam, tissue cytology, and standard microbial culturing to determine the type of the infectious pathogen. To prescribe appropriate therapy, it is important to distinguish between bacterial, fungal, and viral keratitis, as the treatments are quite different. Diagnosis of the causative organism has a substantial prognostic importance. Further, timely knowledge of the nature of the pathogen is also critical to adapt therapy in patients unresponsive to empiric treatment options, which occurs in 10% of all cases. Currently, the identification of the nature of the pathogen that causes keratitis is achieved via microbial culture screening, which is laboratory-based, expensive, and time-consuming. The most frequent pathogens that cause the corneal ulcers are P. aeruginosa and S. aureus. Here, we report a microchip for rapid (<1h) detection of P. aeruginosa (6294), S. aureus(LAC), through on-chip electrical sensing of bacterial lysate. We evaluated the microchip with spiked samples of PBS with bacteria concentration between 10¹ to 10⁸ CFU/mL. The least diluted bacteria concentration in bacteria-spiked samples with statistically significant impedance change was 10 CFU/mL. We further validated our assay by comparing our microchip results with the standard culture-based methods using eye washes obtained from 13 infected mice.

Ocular involvement associated with varicella in adults

BACKGROUND

Varicella is a common infectious disease primarily of childhood that is usually benign and self-limited. It is, however, increasingly seen in adults who are at a higher risk of severe infection. Ocular complications of varicella are relatively uncommon and have been rarely described in adults. We describe herein five adults who developed ocular involvement in association with primary varicella-zoster virus infection.

FINDINGS

Ocular manifestations included acute anterior uveitis in four eyes, with associated stromal keratitis in one of them, epithelial ulcerative keratitis in the two eyes of one patient, and acute retinal necrosis in one eye. One patient with acute anterior uveitis was treated with topical steroids and cycloplegic agents. The four other patients received topical or systemic antiviral drugs, with subsequent resolution of acute ocular inflammatory disease.

CONCLUSIONS

The spectrum of chickenpox-associated ocular complications in adults is wide. Early diagnosis and appropriate management are mandatory to improve visual outcome.

Repertoire of free-living protozoa in contact lens solutions

Background

The repertoire of free-living protozoa in contact lens solutions is poorly known despite the fact that such protozoa may act as direct pathogens and may harbor intra-cellular pathogens.

Methods

Between 2009 and 2014, the contact lens solutions collected from patients presenting at our Ophthalmology Department for clinically suspected keratitis, were cultured on non-nutrient agar examined by microscope for the presence of free-living protozoa. All protozoa were identified by 18S rRNA gene sequencing.

Results

A total of 20 of 233 (8.6 %) contact lens solution specimens collected from 16 patients were cultured. Acanthamoeba amoeba in 16 solutions (80 %) collected from 12 patients and Colpoda steini, Cercozoa sp., Protostelium sp. and a eukaryotic more closely related to Vermamoeba sp., were each isolated in one solution. Cercozoa sp., Colpoda sp., Protostelium sp. and Vermamoeba sp. are reported for the first time as contaminating contact lens solutions.

Conclusion

The repertoire of protozoa in contact lens solutions is larger than previously known.

[Ocular syphilis: 9 cases]

Syphilis is a disease with ocular involvement may be opening and cover all ocular structures. The objective of the study was to retrospectively identify and describe all cases of ocular syphilis diagnosed in the ophthalmology department of Besançon University Hospital from March 2004 to April 2014. Between March 2004 and April 2014, we diagnosed and monitored 9 male patients (13 eyes) with ocular syphilis (1 interstitial keratitis, chorioretinitis associated with a 1 hyalite, 3 panuvéites, 1 chorioretinitis after placoid, 3 bilateral papillary edema). Patients had a mean age of 52.6 years (32-77 years) at diagnosis and the inaugural symptoms were in 100% of cases decreased visual acuity. The follow-up period ranged from 1 month to 5 years. The curative treatment included intravenous antibiotics penicillin G for 3 weeks. All patients had an improvement in their AV (AV initial range "counting fingers" and 0.6 versus AV final between 0.5 and 1 in decimal scale). Syphilis is a disease currently on the rise. It must be systematically sought before any inflammatory disease of the eye or papilledema.

Successful Treatment of Lasiodiplodia theobromae Keratitis - Assessing the Role of Voriconazole

Purpose

The aim of this paper is to report the successful management of the first case of Lasiodiplodia theobromae keratitis in Hong Kong.

Methods

We conducted a case report.

Results

A 43-year-old Chinese male with a history of diabetes developed left eye keratitis after a trauma during tree felling. Fungal keratitis was diagnosed using a confocal microscope on day 1, and L. theobromae was confirmed from the culture. He was given oral voriconazole, topical natamycin, and topical and intracameral amphotericin B. The patient's condition improved after the initial treatment. However, there was a slow progression to descemetocele formation and impending perforation due to corneal melting. Penetrating keratoplasty was performed at 8 weeks after presentation. Final visual recovery was good with no recurrence of infection. The cornea remained clear.

Conclusions

We report the first case of L. theobromae keratitis in Hong Kong, and it is the only case so far that involved the use of oral voriconazole in the combination therapy. Early recognition with the aid of confocal microscopy allowed the early start of treatment. The use of newer antifungal voriconazole topically and orally combined with topical amphotericin B appeared to be useful in the eradication of the fungus and prevention of recurrence. Intracameral antifungals might have improved the clinical management.

LOX-1 and TLR4 affect each other and regulate the generation of ROS in A. fumigatus keratitis

PURPOSE

To explore the relationship between LOX-1 and TLR4 in Aspergillus fumigatus (A. fumigatus) keratitis. To determine LOX-1 and TLR4 can affect each other and regulate inflammation through regulation of the generation of reactive oxygen species (ROS) in A. fumigatus keratitis.

METHODS

The cornea and abdominal cavity extracted neutrophils of susceptible C57BL/6 mice were infected with A. fumigatus. The cornea and neutrophils were pretreated with LOX-1 neutralizing antibody, Polyinosinic acid (Poly(I)) (the inhibitor of LOX-1) or CLI-095 (the inhibitor of TLR4) separately before infection. LOX-1, TLR4 and IL-1β expression were detected in normal and infected cornea by PCR and Western Blot, while ROS was detected in the neutrophils by flow cytometry.

RESULTS

LOX-1, TLR4, IL-1β mRNA and protein levels were up-regulated in C57BL/6 cornea after infection. LOX-1 neutralizing antibody or Poly(I) pretreatment decreased the expression of LOX-1, TLR4 and IL-1β in C57BL/6 cornea after infection and CLI-095 pretreatment decreased the expression of LOX-1, TLR4 and IL-1β in C57BL/6 cornea after infection. ROS generation was increased in C57BL/6 neutrophils after infection, however, ROS generation was decreased in C57BL/6 neutrophils after infection by LOX-1 neutralizing antibody or Poly(I) or CLI-095 pretreatment.

CONCLUSION

LOX-1, TLR4 and IL-1β expression and ROS generation are increased after infection. LOX-1 and TLR4 can affect each other and regulate the generation of ROS in A. fumigatus keratitis. Inhibition of LOX-1 and TLR4 can reduce ROS generation.

The effects of oral and topical corticosteroid in rabbit corneas

BACKGROUND

To determine the most effective route of administration of corticosteroids in the treatment of ocular surface disease, by characterizing the difference between oral prednisolone and topical dexamethasone administration using an animal model.

METHODS

Pharmacokinetic analyses determined the corticosteroid concentrations in the normal ocular tissues of rabbits after oral or topical administration of corticosteroids using LC-MS/MS. In wound healing analyses, the area of the epithelial defect created by keratectomy using a 6-mm trephine was calculated with an image analyzer using an orally or topically steroid-administrated animal model. The average size of basal epithelial cells, the frequency of mitotic basal epithelial cells, the number of squamous cells, and the number of hypertrophic stromal fibroblasts were determined in the enucleated corneal tissues after wound closure.

RESULTS

By slit lamp examination, no remarkable differences were observed between orally and topically administered groups. Pharmacokinetic analyses showed that the distribution of dexamethasone after topical administration was superior to that after oral administration in the cornea. In contrast, both concentrations of corticosteroid applied topically and orally were similar with regards to AUCs (area under the concentration-time curve) in the conjunctiva. Although the healing rate was slower in the topical group, all corneas were almost healed within 96 h in the wound healing analysis. According to the histological analyses of epithelial cells, the average basal cell size was larger, the frequency of mitotic basal cells was greater, and the number of squamous epithelial cell layers was lower in the topically administered group although all of these differences were with no statistical significance. However, the number of hypertrophic stromal fibroblasts in the topically administered group was significantly lower than that in the orally administered group.

CONCLUSIONS

There are different distributions and effects between orally and topically administered corticosteroids on the ocular surface. The data may provide the useful information in selecting the appropriate route of corticosteroid application for the treatment of ocular surface disease.

[Good outcome in Acanthamoeba keratitis]

A 31-year-old woman presented with mild keratitis of her left eye. The use of daily disposable contact lenses, regularly rinsed with tap water, and the development of perineural corneal infiltrates resulted in the clinical suspicion of infection with Acanthamoeba. Corneal epithelial scraping probe for polymerase chain reaction on Acanthamoeba confirmed the clinical diagnosis. Although the treatment was limited to low-dose propamidine monotherapy because of reduced tolerability, the keratitis healed with almost no scarring after 13 months of consequent medication.

Corneal Phaeohyphomycosis Caused by Bipolaris hawaiiensis

Purpose

To report a rare case of keratitis infected by Bipolaris hawaiiensis.

Methods

A patient who was diagnosed as fungal keratitis caused by B. hawaiiensis was retrospectively reviewed for history, clinical characteristics, risk factors, laboratory findings, treatments, and outcomes.

Results

A 63-year-old man with a history of trauma and saw dust in the left eye presented with a corneal ulcer. Eye examination revealed whitish infiltration with a feathery edge and small brownish deposits in the anterior stroma of the left cornea. Numerous septate hyphal fragments were detected in a corneal specimen, and nucleotide sequence analysis identified B. hawaiiensis. Treatment was started with 5% natamycin eyedrops and oral itraconazole. Subsequently, a corneal plaque developed which did not respond to medication and debridement. The patient underwent therapeutic penetrating keratoplasty.

Conclusions

B. hawaiiensis is a rare cause of corneal phaeohyphomycosis. A brownish pigmented infiltration is an important diagnostic clue, however microbiologic studies are required to obtain a definite diagnosis. Although antifungal medication and debridement are the mainstay of most corneal fungal infection, therapeutic penetrating keratoplasty can prevent morbidity related to this fungal infection.

Decreasing HMGB1 levels improves outcome of Pseudomonas aeruginosa keratitis in mice

Pseudomonas (P.) aeruginosa is a Gram negative bacterium widely dispersed in the environment which can cause acute and chronic infections in humans. According to the Centers for Disease Control and Prevention (CDC), the overall incidence of P. aeruginosa infections in USA hospitals averages about 0.4% (4/1000 discharges), and the bacterium is the fourth most commonly-isolated nosocomial pathogen accounting for 10.1% of all hospital-acquired infections. P. aeruginosa keratitis is a severe infection of the eye, progresses rapidly and remains a leading cause of corneal ulcers worldwide. Use of contact lenses is the major risk factor in the USA, while in less industrialized countries, trauma from agricultural accidents are of importance. Animal models of bacterial keratitis are of value in the study of this disease and suggest potential alternative therapeutic targets that are needed urgently due to increasing antibiotic resistance. Recently we have shown success and improved disease outcome after down-regulation of one promising target, high mobility group box1 (HMGB1) using small interfering RNA (siRNA). Testing more clinically relevant approaches are underway to reduce HMGB1 levels in P. aeruginosa keratitis which may hold promise for its treatment.

Fungal keratitis due to Schizophyllum commune: an emerging pathogenic fungus

Fungal keratitis due to Schizophyllum commune is very rare. In this study, we report the clinical and microbiological profile of five patients with fungal keratitis due to S. commune. Direct microscopic examination of corneal scrapings from all five patients showed septate branching hyaline fungal filaments. Similarly, in all five patients Sabouraud dextrose agar (SDA) plates inoculated with corneal scrapings showed white, cottony colonies on the second day of incubation. Lactophenol cotton blue stained wet preparation of 7-day-old colonies on SDA revealed clamp connections and no spores. The fungus was identified by its characteristic clamp connections, fan-shaped bracket fruiting body with pinkish-grey longitudinally split-radiating gills. The phenotypic identification of one of the five isolates further conformed by ITS sequencing. Treatment outcome was available for two of the five patients; in these two patients, the keratitis resolved with topical natamycin.

Preclinical assessment of scleral lens as a reservoir-based ocular therapeutic system

PURPOSE

Bacterial keratitis is a sight threatening infection of the cornea which remains one of the most important potential complications of contact lens use. If the corneal ulcer is small, peripheral with no impending perforation present, intensive monotherapy with fluoroquinolones could be used. Therefore, a study was conducted with the objective to provide pharmacological data of the intra-ocular diffusion after administration of Ofloxacin using a scleral lens reservoir, as well as an evaluation of surface tolerability in rabbits.

MATERIALS AND METHODS

Samples of corneas, aqueous humor and vitreous were collected to measure the drug levels of Ofloxacin using High Performance Liquid Chromatography. The corneas were examined by electron microscopy scanning and the eyeballs by light polarizing microscopy in order to evaluate surface tolerability.

RESULTS

Ofloxacin levels found in the aqueous humor and cornea were higher than those previously reported. The mean Ofloxacin corneal levels exceeded the MIC (Minimum Inhibitory Concentration) for which 90% of isolates are indicated for all bacteria implicated in keratitis.

CONCLUSION

To our knowledge, this is the first preclinical study assessing local tolerance and intra-ocular diffusion of Ofloxacin after administration using a scleral lens reservoir.

Contact Lens-related Polymicrobial Keratitis from Pantoea agglomerans and Escherichia vulneris

Purpose

To report a case of polymicrobial keratitis caused by Panotea agglomerans, Escherichia vulneris and coagulase-negative Staphylococcus in a patient who cleaned their extended wear contact lenses with only tap water for 2 weeks.

Methods

Case report.

Results

An adult presented with a painful red eye after wearing the same contact lenses for two weeks. The patient admitted to taking the contacts out in the evening and cleaning them with tap water before reapplying them in the morning. Exam revealed a 2.5 mm paracentral corneal ulcer in the left eye. Culture results from corneal scrapings were positive for P. agglomerans, E. vulneris and coagulase-negative Staphylococcus.

Conclusions

This is the first report of P. agglomerans and E. vulneris keratitis in association with contact lens wear. Both strains of P. agglomerans and E. vulneris were pansensitive to all tested antibiotics.

Evaluation of the visual function of patients with locked-in syndrome: Report of 13 cases

Although visual function is thought to be preserved in patients with locked-in syndrome (LIS), enabling them to communicate through vertical or lateral eye movements or blinking of the upper eyelid, nothing is known about the actual visual function of patients with LIS. The goal of this study is to evaluate the visual function of patients with LIS which may enable better evaluation of the state of consciousness of these patients. Patients with LIS seen in a single neurovascular unit of a tertiary center between 1997 and 2013 were retrospectively reviewed. Each patient had a specialized neuro-ophthalmological evaluation under optimal environmental conditions (light, contrast, examination distance, head position, best ergonomic adaptation, and establishment of a means of communication with help from the patient's friends/family). Visual acuity, extraocular eye movements, confrontational visual field, slit lamp and fundus examination were performed. Thirteen patients (6M/7F) were included in this study. Mean visual acuity was 20/60. Oculomotor examination was abnormal in 77%. Forty-six percent of patients presented binocular diplopia mainly related to a VIth nerve palsy. One patient presented complete ophthalmoplegia. Forty-six percent of patients had nystagmus responsible for oscillopsia (oculopalatal tremor). An abnormal visual field was observed in 17% of patients, and abnormal pupillary light response leading to photophobia was present in 22% of patients. Keratitis or dry eye syndrome was present in most patients and was a major cause of pain and visual impairment. Our results suggest that the visual function is impaired in all patients with LIS. This impairment is multifactorial including mostly binocular diplopia or oscillopsia but also refractive errors, dry eye syndrome, keratitis or visual field defect. This altered visual function may alter the ability of the patient to interact with his environment and lead to underestimation of their state of consciousness. An ophthalmologic evaluation would allow for improvement of these patients' comfort, their ability to communicate, and the assessment of their state of consciousness.

Acanthamoeba and Fusarium interactions: A possible problem in keratitis

The incidence of Acanthamoeba and Fusarium species has increased in contact lens-related infectious keratitis. They share several environments and cases of co-infection have been reported. The interaction between the amoebae and other microorganisms may result in significant changes for both, like increased virulence in mammalian hosts. In this study, we evaluated the interaction of three Acanthamoeba castellanii strains with Fusarium conidia and the possible implications on keratitis. F. conidia were internalized by A. castellanii strains and were able to germinate inside the amoebae. The co-culture with the live amoebae, as well as the amoebal culture supernatant and lysate, increased the fungal growth significantly. Moreover, live F. solani and its culture supernatant enhanced the survival of amoebae, but in a different way in each amoebal strain. The encystment of the A. castellanii strain re-isolated from rat lung was increased by the fungus. These results show that A. castellanii and F. solani interaction may have an important influence on survival of both, and specially indicate a possible effect on virulence characteristics of these microorganisms. These data suggest that the A. castellanii-F. solani interaction may cause severe impacts on keratitis.

Isolation and genotyping of Acanthamoeba strains (T4, T9, and T11) from amoebic keratitis patients in Iran

The continuous increase in Acanthamoeba keratitis, a severe corneal infection, worldwide is mainly due to the increase in the number of soft contact lens users. In the present study, which involves a 5-year study, a total of 138 corneal scraps and contact lenses together with their paraphernalias were obtained from suspected amoebic keratitis patients. All samples were cultured using culture-enrichment method. Pathogenic assay, using thermotolerance and osmotolerance tests were also performed on the positive strains. Sequencing of the isolated strains was done by targeting the DF3 region of 18s rRNA gene. The results revealed that 18 (13 %) of patients were infected with Acanthamoeba spp. As expected, T4 genotype was the most common genotype among the clinical samples; however, in three cases, Acanthamoeba belonging to T11 and T9 were detected. Interestingly, T9 genotype, commonly classified as non-pathogenic amoebae, was identified as a causal agent of a patient with amoebic keratitis. From the pathogenic assay, four strains belonging to T4 genotypes were highly pathogenic. This is the first report of Acanthamoeba T9 genotypes isolated in Iran and the first report of T9 type occurring in amoebic keratitis patients worldwide. Due to the increasing trend of amoebic keratitis (AK) and the identification of new genotypes, such as T9 as the causative agent of AK, more researches in this field are necessary in the region and the world at large.

Ocular toxicity assessment of chronic sildenafil therapy for pulmonary arterial hypertension

PURPOSE

The aim of this study was to investigate possible functional and structural ocular changes caused by chronic sildenafil therapy to treat pulmonary arterial hypertension (PAH).

METHODS

Case-control study included patients with pulmonary arterial hypertension: chronically using sildenafil and without sildenafil treatment. A comprehensive ophthalmologic exam including ectoscopy, extrinsic ocular motility, logMAR visual acuity measurement, contrast sensitivity test, color test, anterior segment biomicroscopy, Schirmer test 1, intraocular pressure, fundus exam under pupil dilation, fundus pictures, time domain and spectral domain optical coherence tomography, ocular Doppler ultrasound were performed. Full-field electroretinography (ERG) was tested for each eye in a subgroup of sildenafil-treated patients.

RESULTS

Twenty patients from each group were tested. Bilateral severe keratitis was found in seven (35 %) patients under sildenafil therapy. Lacrimal film break-up time (BUT) was significantly reduced (p = 0.006 respectively) and Doppler ultrasound showed a reduced resistance index of the central retinal artery in the group of sildenafil users (p = 0.019). No diffuse retinal functional abnormalities were found in ERG in treated patients. Visual acuity, contrast sensitivity and color discrimination were normal in both groups. No abnormalities were found in both time-domain and spectral-domain OCT for retinal parameters.

CONCLUSIONS

One-third of the treated PAH group showed severe bilateral keratitis. This finding could be related to connective tissue abnormalities usually present in patients with this condition that might be exacerbated with the sildenafil usage. The resistance index of the central retinal artery was diminished in the chronic users group and it could be associated to the vasodilation caused by the medication in the choroidal vessels. An ophthalmic assessment for these patients is recommended to diagnose and treat possible ocular surface and choroidal blood flow abnormalities caused by sildenafil.

Keratoneuritis is not pathognomonic of Acanthamoeba keratitis: a case report of Pseudomonas keratitis

The presence of keratoneuritis in a radial pattern is considered to be a virtually pathognomonic sign of Acanthamoeba keratitis. We report a case of a massive keratoneuritis as a presenting sign in Pseudomonas keratitis in a contact lens wearer, thereby further challenging this concept.

Levator lengthening technique using cartilage or fascia graft for paralytic lagophthalmos in facial paralysis

INTRODUCTION

Lid loading using gold weights has been commonly used to treat paralytic lagophthalmos (PL); however, the procedure has a relatively high complication rate and the availability of these plates varies among social circumstances. We used a levator lengthening (LL) technique, which originally elongated the levator aponeurosis by inserting a fascia graft between the edge of the levator aponeurosis and the tarsal plate. However, because this procedure tends to result in a wide residual lagophthalmos, we changed the graft material from fascia to conchal cartilage. In this study, we describe in detail our experience with LL using the cartilage graft.

METHODS

LL was performed in 18 patients with PL. Fascia grafts were used in seven patients and cartilage grafts in 11. Static reconstructions of the lower eyelid and eyebrow were also performed in most patients. Efficacy was evaluated from patient reports of ocular symptoms and by measuring the palpebral fissure width at opening and closing for both eyes.

RESULTS

All patients experienced improved ophthalmological symptoms, which were more apparent in cartilage cases. The average palpebral fissure at eyelid closure was 1.8 mm in cartilage cases and 4.0 mm in fascia cases. In cases where an eyebrow lift was concurrently performed, the residual lagophthalmos became wider in fascia grafting but remained acceptable in cartilage grafting.

DISCUSSION

LL is a simple and useful procedure for treating PL with higher efficacy when a cartilage graft is used. However, the level of the upper eyelid can be easily adjusted by changing the fixation position of the cartilage. Additional experience is required to obtain more consistent outcomes.

Alternaria keratitis after uneventful phacoemulsification in an otherwise healthy adult

Background

Fungal infections of self-sealing corneal incisions in cataract surgery are scarce. We report a case of Alternaria keratitis, several weeks after uneventful clear-cornea phacoemulsification.

Findings

A 42-year-old woman, with a history of retinitis pigmentosa, complained of painful red right eye, 45 days after uneventful self-sealing clear-cornea phacoemulsification. Slit-lamp examination revealed multiple snow-like contiguous stromal infiltrates, with irregular margins, and no epithelial defect. These infiltrates were unresponsive to topical quinolones and topical corticosteroids as well as oral valaciclovir. Culture from corneal biopsy specimen grew Alternaria species. Management consisted of topical amphotericin-B, and then a combination of topical and oral voriconazole. The corneal infiltrates progressively healed. One year later, the best-corrected visual acuity was 20/400.

Conclusions

Fungal infection, particularly Alternaria keratitis, should be considered in the differential diagnosis of delayed post-cataract surgery keratitis. Prompt diagnosis and management are mandatory to improve visual prognosis.

Microbial Profile of Corneal Ulcers in a Tertiary Care Hospital in South India

PURPOSE

To identify the prevalence and microbial profile of infectious keratitis in a tertiary eye care hospital, and to test for the in vitro antimicrobial resistance of the bacterial isolates.

METHODS

A total of 312 patients presenting to a tertiary eye care hospital with infected corneal ulcer were enrolled in this study. Their socio-demographic data and risk factors were recorded. Corneal scrapings collected from the edge of the ulcer were processed for direct gram stain and KOH mount. Culture was recovered on blood agar, chocolate agar, MacConkey agar and Sabouraud's dextrose (SDA) agar in multiple C shaped streaks. After overnight incubation, bacterial culture was followed by standard biochemical tests and antimicrobial sensitivity according to the clinical and laboratory standards institute (CLSI) guidelines. Inoculated SDA was inspected daily for up to 10 days and the growth was identified by its colony morphology, pigment production and lacto-phenol cotton blue mount examination.

RESULTS

Of 312 patients, a microbial etiology was established in 117 cases (37.5%). Of these, 72 (61.5%) were male. The age range of 41-60 years was the most affected group. Of 117 positive cases, 52 (44.5%) were bacterial, 58 (49.5%) were fungal and 7 (6%) patients showed mixed bacterial and fungal infection. The most common isolated fungus was Fusarium which was detected in 36 (31%) cases, followed by Aspergillus spp in 13 (11%) subjects. Staphylococcus aureus was the most common isolated bacteria. All Gram positive cocci were susceptible to vancomycin followed by gatifloxacin, whereas all Gram negative bacilli were susceptible to gatifloxacin.

CONCLUSION

Routine microbiological examination of patients with corneal ulcer is necessary in order to analyze and compare the changing trends of the etiology and their susceptibility patterns.

Antifungal Susceptibility and Phylogeny of Opportunistic Members of the Genus Fusarium Causing Human Keratomycosis in South India

Fusarium species are reported frequently as the most common causative agents of fungal keratitis in tropical countries such as India. Sixty-five fusaria isolated from patients were subjected to multilocus DNA sequencing to characterize the spectrum of the species associated with keratitis infections in India. Susceptibilities of these fusaria to ten antifungals were determined in vitro by the broth microdilution method. An impressive phylogenetic diversity of fusaria was reflected in susceptibilities differing at species level. Typing results revealed that the isolates were distributed among species in the species complexes (SCs) of F. solani (FSSC; n = 54), F. oxysporum (FOSC; n = 1), F. fujikuroi (FFSC; n = 3), and F. dimerum (FDSC; n = 7). Amphotericin B, voriconazole, and clotrimazole proved to be the most effective drugs, followed by econazole.

Microbial Keratitis at an Urban Public Hospital: A 10-Year Update

Purpose

To review the epidemiology, risk factors, microbiologic spectrum, and treatment of microbial keratitis during a five-year period at an urban public hospital with comparison to similar findings a decade earlier at the same hospital.

Methods

Retrospective chart review in the 5-year interval 2009 through 2014 compared to previously reported cases 2000 through 2004 [Eye & Contact Lens 33(1): 45-49, 2007]. Comparative primary outcome measures included best-corrected visual acuity (BCVA), risk factors, culture and sensitivities, treatment, and complication rates.

Results

318 eyes with microbial keratitis were identified. Contact lens wear, ocular trauma, and ocular surface diseases were the most common risk factors. The culture and recovery rates were 73% and 66% respectively. Gram-positive organisms represented 46%, gram-negative organisms 39%, fungal organisms 15%, and Acanthamoeba <1% of corneal isolates. No common corneal pathogens were resistant to aminoglycosides or vancomycin. 48% of cases were initially treated with fortified antibiotics, 43% with fluoroquinolone monotherapy, and 6% with antifungals. 40% of cases received inpatient treatment. At resolution, average BCVA was 20/82 [logMAR 0.61] with 8% of cases resulting in light perception or worse vision. The perforation rate was 8%. 6% of cases underwent urgent penetrating keratoplasty and 4% of cases underwent urgent enucleation or evisceration. Compared to the prior study, significant differences were: (1) lower culture but higher recovery rates, (2) lower admission rate, (3) more contact lens-related cases of Pseudomonas ulcers, (4) lower resistance of coagulase-negative Staphylococcus to aminoglycoside antibiotics, (5) improved BCVA at resolution, and (6) lower associated complication rates.

Conclusion

Microbial keratitis remains a clinical challenge in the urban public hospital setting. In the past ten years, epidemiology has shifted towards greater contact lens wear with more Pseudomonal infections. Visual outcomes have not worsened despite a shift away from routine culture and inpatient care to fluoroquinolone monotherapy and outpatient management.