Ocular nocardia infections with special emphasis on the cornea

A case of disseminated nocardiosis with orbital apex involvement and endophthalmitis

Nocardia is a rare cause of ocular infections and most commonly occurs secondary to trauma. Systemic Nocardiosis may have ocular involvement in rare cases. We report a case of disseminated nocardiosis with orbital apex involvement and endophthalmitis in an immunocompromised patient. The patient presented with respiratory sepsis, and later developed complete ptosis and ophthalmoplegia in the left eye. This was on the background of treatment with high-dose prednisolone. Magnetic resonance imaging showed enhancement of the entire clivus, extending into the left orbital apex and cavernous sinus. The patient was initially treated empirically for CNS tuberculosis. Bronchoscopic cultures returned positive for Nocardia farcinica, and the patient was treated with trimethoprim/sulfamethoxazole and weaned off previous corticosteroids.

Nocardia keratitis after small incision lenticule extraction (SMILE)

We report the case of a female patient in her late 20s who visited the clinic with concerns about poor vision, redness, watering and a burning sensation in her left eye 2 weeks after undergoing a small incision lenticule extraction. She had no history of systemic illness or immunosuppressed status. On slit lamp examination, she was found to have corneal stromal infiltrates in the interface at multiple locations. Given the clinical diagnosis of microbial keratitis, corneal scraping of the interface infiltrate was performed and sent for microbiological examination revealing gram-positive, thin, beaded filaments that were acid-fast positive and later identified by growth in culture media as Nocardia species. This case was managed successfully with the use of topical amikacin and systemic trimethoprim-sulfamethoxazole with complete resolution of infection.

Atypical microbial keratitis

Atypical microbial keratitis refers to corneal infections caused by micro-organisms not commonly encountered in clinical practice. Unlike infections caused by common bacteria, cases of atypical microbial keratitis are often associated with worse clinical outcomes and visual prognosis. This is due to the challenges in the identification of causative organisms with standard diagnostic techniques, resulting in delays in the initiation of appropriate therapies. Furthermore, due to the comparatively lower incidence of atypical microbial keratitis, there is limited literature on effective management strategies for some of these difficult to manage corneal infections. This review highlights the current management and available evidence of atypical microbial keratitis, focusing on atypical mycobacteria keratitis, nocardia keratitis, achromobacter keratitis, and pythium keratitis. It will also describe the management of two uncommonly encountered conditions, infectious crystalline keratopathy and post-refractive infectious keratitis. This review can be used as a guide for clinicians managing patients with such challenging corneal infections.

Nocardia infection following ocular surface surgery

OBJECTIVE

To investigate the clinical characteristics and treatment outcomes of Nocardia infection after ocular surface surgery.

METHODS

This is a retrospective study. Eight cases of culture-proven Nocardia infection, which developed within 1 month after ocular surface surgery were included. Demographics and clinical history of patients were investigated.

RESULTS

There were 8 eyes (2 left and 6 right) of 8 patients (5 males and 3 females), aged 27-65, with a median age of 52.9 years. Three cases underwent pterygium excision, three were subjected to conjunctival flap covering, and two were treated with lamellar corneal transplantation. The time interval between previous surgery and the onset of symptoms varied from 7 to 28 days (mean = 20.5 ± 7.13 days). All the cases presented grey-white infiltrates at the surgical incision site while appearing with six corneal ulcers and two conjunctival ulcers. Filaments of Nocardia were founded by confocal microscopy in two of the five cases. All responded poorly to medical therapy. Seven of the eight cases were treated with reoperation. Nocardia infection recurred in three cases after reoperation, and one was eviscerated.

CONCLUSIONS

Surgical trauma is a risk factor for ocular Nocardia infection. Nocardia infection should be suspected when secondary infection occurs in a surgical incision with an atypical clinical presentation. The use of corticosteroids may influence the efficacy of drugs. Complete removal of lesions may lower the recurrence of Nocardia infection with poor drug treatment effects.

Nocardia and Streptomyces keratitis in dogs: In vivo detection of filamentous bacteria by confocal microscopy

OBJECTIVE

To describe the clinical features of dogs with Nocardia and Streptomyces keratitis, including the results of in vivo confocal microscopy examinations.

ANIMAL STUDIED

A 15-year-old, male-castrated, miniature Schnauzer was presented with a multilobulated, cystic, pink, ulcerated corneal mass with surrounding dense leukocyte infiltrates. Cytologic evaluation of a corneal scraping identified pyogranulomatous inflammation and filamentous bacteria. Nocardia nova was cultured from corneal samples. Anterior lamellar keratectomy was performed to excise the affected corneal region and histopathologic evaluation confirmed the diagnosis of pyogranulomatous keratitis. A 10-year-old, male-castrated, Yorkshire terrier was presented for evaluation of a chronic anterior stromal corneal ulcer associated with a brown corneal plaque. Cytologic evaluation of a corneal scraping identified suppurative inflammation and filamentous bacteria. A Streptomyces sp. was cultured from corneal samples. The keratitis in both dogs resolved with therapy.

PROCEDURES

In vivo confocal microscopy examination of the corneal lesions in both dogs revealed dense accumulations of leukocytes and clusters of hyperreflective, slender, branching bacterial structures that were approximately 1.5-2.0 μm in diameter and 25-50 μm in length. Confocal microscopy imaging of the Nocardia isolate in vitro, and ex vivo canine corneas experimentally infected with the bacteria, was performed to corroborate the in vivo findings. The morphology of the filamentous bacteria was similar between the in vivo, in vitro, and ex vivo confocal microscopy examinations.

CONCLUSIONS AND CLINICAL RELEVANCE

Nocardia and Streptomyces spp. can be associated with infectious keratitis in dogs. In vivo detection of filamentous bacteria in the cornea can be accomplished by confocal microscopy.

A Case of Nocardia africana-Related Keratitis

Nocardia spp. are gram positive, aerobic, weakly acid-fast bacteria. Nocardia spp. keratitis is a rare ocular infection classically described following corneal injury or vegetative and soil exposure. However, keratitis caused by Nocardia africana had never been reported in the literature. We first reported a 70-year-old male who had a traumatic ocular injury to his left eye a month ago. With his complaint of left eye pain, reduced vision, and light sensitivity, the slit-lamp biomicroscopy showed the superficial multi-lobulated epithelial infiltration located at the inferior cornea with a positive fluorescein stain. Microscopic workup from corneal specimens demonstrated dry and chalky white colonies on blood agar and Lowenstein-Jensen media resembling Nocardia spp. The MALDI-TOF MS analyses using VITEK® MS exhibited N. africana. The corneal lesion was treated with 2% amikacin topical eye drops and responded well. The careful history-taking, precise clinical examinations, and meticulous microscopic assessment were the cornerstones of diagnosis. Definite diagnosis and timely treatment were essential to prevention of ocular morbidity in N. africana.

Surgically-induced necrotising scleritis complicated by Nocardia infection following routine cataract surgery

Necrotising scleritis is a rare, inflammatory condition with potentially devastating visual consequences. It can be associated with inflammatory and infectious causes, and has been linked to several different ocular procedures. We present a difficult case of a patient with surgically-induced necrotising scleritis following routine phacoemulsification cataract surgery, who developed a secondary Nocardia bacterial infection. He required a number of surgical interventions and prolonged antibiotic therapy, suffering recurrent scleral abscesses. A literature review accompanies our case report. Prompt recognition and adequate investigation for underlying inflammatory and infective causes are vital to maintain integrity of the globe and ensure suitable treatment of this challenging condition.

Nocardia Endophthalmitis- Prophylactic Prevention with an Innovative Approach

Background:

Nocardia is a common cause of endophthalmitis in southern India. It is an aggressive disease with a poor prognosis.

Objective:

This study was conducted using an amikacin antibiotic in the drip irrigation of balanced saline solution (BSS) during the surgery to prophylactically study the occurrence of Nocardia endophthalmitis and any subsequent toxic effects of the antibiotics used.

Methods:

Prospective study period was of 6 months, starting from July to December-2018. Preoperative and postoperative specular counts and macular thickness using Ocular Coherence Tomography (OCT) were compared with any incidence of Nocardia endophthalmitis. A total of 500 patients operated for manual SICS were randomly assigned into 2 groups. The first group of 250 patients received antibiotic amikacin added to the Balanced Saline Solution (BSS) irrigating solution throughout the course of the surgery. The second control group received no antibiotics. Manual SICS was performed on all 500 patients by a single surgeon and was found to be uneventful. Pre- and postoperative corneal endothelial cell density and mean macular thickness using OCT were taken and recorded of all the patients, respectively, and data obtained were statistically compared.

Results:

No incidence of Nocardia endophthalmitis among the cataract surgeries operated was found. There was no drug-related toxicity to the cornea or macula. Furthermore, no incidence of Nocardia endophthalmitis has been reported since 2018 after using antibiotics.

Conclusion:

A simple routine of adding amikacin in the drip prophylactically during the course of surgery helped us prevent Nocardia endophthalmitis with no side effects. Also, it will be an innovative technique that is economically feasible and effective in regions where Nocardia endophthalmitis is prevalent.

Diagnostic armamentarium of infectious keratitis: A comprehensive review

Infectious keratitis (IK) represents the leading cause of corneal blindness worldwide, particularly in developing countries. A good outcome of IK is contingent upon timely and accurate diagnosis followed by appropriate interventions. Currently, IK is primarily diagnosed on clinical grounds supplemented by microbiological investigations such as microscopic examination with stains, and culture and sensitivity testing. Although this is the most widely accepted practice adopted in most regions, such an approach is challenged by several factors, including indistinguishable clinical features shared among different causative organisms, polymicrobial infection, long diagnostic turnaround time, and variably low culture positivity rate. In this review, we aim to provide a comprehensive overview of the current diagnostic armamentarium of IK, encompassing conventional microbiological investigations, molecular diagnostics (including polymerase chain reaction and mass spectrometry), and imaging modalities (including anterior segment optical coherence tomography and in vivo confocal microscopy). We also highlight the potential roles of emerging technologies such as next-generation sequencing, artificial intelligence-assisted platforms. and tele-medicine in shaping the future diagnostic landscape of IK.

Post-traumatic exogenous endophthalmitis caused by Nocardia farcinica

A case report of post-traumatic exogenous endophthalmitis caused by Nocardia farcinica, including treatment procedures, microbiology examination, and systemic medications. A 23-year-old male suffered a penetrating corneal injury that was treated with sutures. On the thirteenth day after the final suture was removed, an anterior uveitis developed and progressed to whitish, plump, nodular, and tufted exudates within the anterior chamber over the next 10 days; this led to an indication for intraocular surgery. Anterior chamber lavage and resection of solid fibrinous exudates (using a vitrectomy knife) for a complete microbiological examination were performed. Nocardia farcinica was identified. Systemic medications were chosen according to sensitivity, and a fixed combination of sulfamethoxazole 400 mg/trimethoprim 80 mg was administered long-term (months). In this case, accurate, early detection of an atypical infectious agent and determination of its sensitivity to antibiotic treatment enabled effective treatment that achieved the best functional and anatomical results under the circumstances.

Nocardia keratitis mimicking superior limbic keratoconjunctivitis and herpes simplex virus

Purpose

Nocardia keratitis is a rare type of infectious keratitis and may mimic other corneal diseases and lead to delay in diagnosis. This case illustrates how Nocardia often escapes accurate diagnosis due to its insidious onset, variable clinical manifestations, and unusual characteristics on cultures.

Observation

The patient presented with an epithelial defect and superior pannus and scarring, which was misdiagnosed as superior limbic keratoconjunctivitis (SLK) and herpes simplex virus (HSV) keratitis. Repeat corneal scraping cultures, smears, and conjunctival biopsy were necessary to elucidate the diagnosis. It can be effectively treated with the intravenous preparation of trimethoprim-sulfamethoxazole 80 mg/mL (brand name SEPTRA) used topically as eye drops.

Conclusion

The diagnosis of Nocardia keratitis relies on a high clinical suspicion and a prompt corneal scraping with culture. Due to its potential for rapid resolution with early therapy, it is important to isolate Nocardia early in its disease course.

Importance

Topical amikacin had been the standard of care for Nocardia keratitis for many years. However, recently there is increasing resistance of Nocardia to amikacin. SEPTRA offers an alternative therapy. Nocardia keratitis mimics other infectious and inflammatory etiologies so rapid diagnosis and treatment is critical in the prevention of long-term complications.

Current diagnostic tools and management modalities of Nocardia keratitis

Nocardia species are an uncommon but important cause of keratitis. The purpose of this review is to discus previous published papers relation to the epidemiology, etiology, diagnosis and management of Nocardia keratitis. Nocardia asteroides is the most frequently reported from Nocardia keratitis. Pain, photophobia, blepharospasm and lid swelling are mainly clinical manifestations. Usual risk factors for Nocardia keratitis are trauma, surgery, corticosteroids, and contact lens wear. Several antibiotics were used for treatment of Nocardia infection but according to studies, topical amikacin is the drug of choice for Nocardia keratitis. Topical steroid should not prescribe in these patients. In conclusion, although Nocardia keratitis is rare, early diagnosis and treatment are essential to prevent any scar formation and preserve a good visual acuity.

Post phacoemulsification wound infection by Nocardia cyriacigeorgica: a rare acid-fast organism

Tunnel infection is one of the most dreaded infections, post phacoemulsification. Most cases reported till now are caused by Gram-positive and Gram-negative bacteria or fungi and very few cases by the acid-fast organisms. Ocular infections by Nocardia usually have poor prognosis. Here, we report a case of tunnel infection, its management and microbiological identification of cause behind it, that is, Nocardia cyriacigeorgica a rare acid-fast microorganism.

Treatment-Resistant Bacterial Keratitis: Challenges and Solutions

Bacterial keratitis is an important ophthalmic emergency and one of the most common causes of corneal blindness. The main causes of treatment resistance in bacterial keratitis are failure to eliminate predisposing factors, misdiagnosis and mistreatment. At first, exogenous, local and systemic predisposing factors that disturbing ocular surface must be eliminated to improve corneal ulcers and to prevent recurrences. Smears and scrapings for staining and culture are indispensable diagnostic tools for cases of sight-threatening keratitis (centrally located, multifocal, characterized by melting, painful). Main treatment agents in bacterial keratitis treatment are topical antibiotics. Until the results of culture antibiograms reach the ophthalmologist, empirical antibiotic selections based on direct microscopic examination and gram stain findings are the most appropriate initial treatment approach currently. S. aureus and coagulase-negative staphylococci (CoNS), the most common gram-positive agents, have resistance rates of more than 30% for fluoroquinolone and methicillin. Multidrug resistance rates are similarly high in these microorganisms. P. aeruginosa is the most common gram-negative micro-organism, in case of multidrug-resistant isolates, both functional and anatomical prognosis of the eyes are very poor. In cases of sight-threatening and resistant keratitis, antibiotic susceptibility testing containing imipenem, colistin, and linezolid is seeming to be an important requirement. Despite its efficiency limited to superficial cases, a nonpharmaceutical anti-infective treatment option such as corneal crosslinking for bacterial keratitis is an emerging hope, while antibiotic resistance increases.

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Infectious Keratitis Caused by Rare and Emerging Micro-Organisms

PURPOSE

To provide a comprehensive review of rare and emerging micro-organisms causing infectious keratitis.

MATERIAL AND METHODS

A literature search was performed using PubMed Medline, Cochrane Library Database, EMBASE and Scopus (1960 onwards), using the terms: keratitis caused by rare pathogens; mycotic keratitis; fungal keratitis; bacterial keratitis; infectious keratitis; infective keratitis; atypical fungal keratitis; fungal keratitis caused by rare organisms; fungal keratitis caused by rare ocular pathogen; atypical bacterial keratitis; bacterial keratitis caused by rare organisms; bacterial keratitis caused by rare ocular pathogen. All relevant articles were included in this review.

RESULTS

A total of 1232 articles matched our search strategy of which 124 articles were included in this mini-review. The rare and emerging bacteria causing keratitis include atypical mycobacteria, Nocardia spp., Chrysebacterium spp., Delftia acidovorans, Kocuria spp., Enterococcus spp., Bartonella henslae, Achromobacter spp. and others. The rare and emerging fungi causing keratitis include Pythium spp., Alternaria spp., Acremonium spp., Cladosporium spp., Curvularia spp., Bipolaris spp., Microsporidia spp., Pseudallescheria spp., Colletotrichum spp., and others. The clinical presentation of these cases is variable. While a few organisms produce characteristic clinical features, rest present similar to bacterial or fungal keratitis with variable response to routine treatment. A strong degree of suspicion is therefore essential for its diagnosis. Special investigations like polymerase chain reaction, gene sequencing, mass spectroscopy and enzyme-linked immunosorbent assay are required for accurate identification of these organisms. Culture-sensitivity is extremely useful as drug resistance to routinely used anti-microbial drugs is common. Prognosis is usually poor for keratitis with Pythium spp., Pseudallescheria spp., Arthrographis spp., Purpureocillium spp., Kociria spp. and Achromobacter spp.

CONCLUSION

Keratitis caused by rare and emerging micro-organisms must be suspected in cases where the infection runs an unusual course or shows a poor response to standard anti-microbial drugs. Early diagnosis and timely treatment hold the key for a good outcome.

Nocardia endophthalmitis in a child: Distinct clinical and imaging features on orbital CT scan

Nocardia is a rare cause of endophthalmitis in immunocompetent individuals with poor visual outcomes. We, herein report a 15 month otherwise healthy child, who presented with hyphema, vitreous hemorrhage and secondary glaucoma following a vague history of trauma in the left eye 2 months before presentation. He presented a week later with features of panophthalmitis which were confirmed on B-scan and orbital CT scan. CT scan with contrast revealed the presence of multiple ring enhancing abscesses in the vitreous cavity and also in the intraconal space. Evisceration was done and smear and cultures revealed Nocardia. Rare presentation in a healthy pediatric patient and typical CT scan findings are discussed.

Diagnosis, Clinical Presentations, and Outcomes of Nocardia Endophthalmitis

PURPOSE

To describe the clinical presentations, diagnosis, and management outcomes of Nocardia endophthalmitis.

DESIGN

Retrospective, interventional, multicenter case series.

METHODS

The study was conducted in a multicentric institutional practice setup and included 25 eyes of 25 patients with culture-proven Nocardia endophthalmitis. Anterior chamber fluid and/or vitreous and/or intraocular lens were submitted for microbiological evaluation in all cases. Patients with non-Nocardia etiology and those that were culture negative were excluded. Case records were studied and data regarding demography, clinical presentations, interventions received, and final visual and anatomic outcomes were noted. The main outcome measures were final visual outcomes and factors determining them.

RESULTS

The mean age of the patients was 54.7 ± 22.9 years. By the etiology of infection, 18 (75%) eyes were post-cataract surgery (operated elsewhere), 3 (12.5%) eyes were posttrauma, and 3 (12.5%) eyes were endogenous. The final follow-up was a mean of 14.25 ± 30.35 months, median 2 months. The odds of a favorable outcome were 42.5 (95% confidence interval [CI] 3.15 to 571.84, P = .0047) when the vision was more than hand motions at presentation, 9.42 (95% CI 0.92 to 95.89, P = .05) in male sex, 21 (95% CI 0.9 to 489.7, P = .05) when presentation was within 48 hours, and 2.5 (95% CI 0.23 to 26.48, P = .44) with primary vitrectomy instead of a biopsy. The in vitro susceptibility was poor for vancomycin and was best for amikacin.

CONCLUSIONS

The visual outcome in Nocardia endophthalmitis is very guarded when presenting vision is poor. On diagnostic confirmation or high index of suspicion, intravitreal amikacin is preferred.

Diagnostic Challenges in Nocardia Keratitis

OBJECTIVE

To present a case of diagnostic confusion in Nocardia keratitis in a contact lens wearer and to illustrate the characteristic clinical findings of this rare entity.

METHODS

Case report of Nocardia keratitis that was mistaken for acanthamoeba, herpetic, and fungal keratitis in three tertiary corneal referral centers before the correct diagnosis of Nocardia infection was made.

RESULTS

A 29-year-old contact lens wearer was referred to our hospital for a contact lens-associated bacterial keratitis, not improving under standard bacterial treatment. Biomicroscopy revealed a circular corneal ulcer and pinhead lesions arranged in a wreath pattern. Initial scraping revealed no positive cultures and confocal microscopy findings were suspicious for fungal keratitis. Only after a poor response to protozoal and fungal treatment, and a negative herpes serology, Nocardia was suspected. This suspicion was confirmed with a positive culture and the topical amikacin and ciprofloxacin were started. The infiltrate responded promptly and resolved, leaving a small corneal scar and a good visual recovery.

CONCLUSION

Because of its infrequent occurrence and its variable clinical picture, Nocardia keratitis is easily misdiagnosed. Although a rare entity, this infection should be added to the differential diagnosis in contact lens-related keratitis not responding to first-line antibiotics and presenting with patchy anterior stromal infiltrates.

Disseminated Nocardiosis with retinal abscess in a patient treated for bullous pemphigoid

Purpose

To report a case of disseminated Nocardiosis with retinal and intracranial lesions.

Observations

A 49-year-old woman immunosuppressed because of treatment given for bullous pemphigoid presented with altered mental status and multiple intracranial lesions on imaging. The patient was found to have multiple retinal lesions in both eyes, including a subretinal abscess in the right eye. The patient underwent brain biopsy, confirming Nocardia farcinica histopathologically and in culture.

Conclusions and Importance

Ocular Nocardiosis is a rare disease with varying prognosis that requires prompt diagnosis to ensure appropriate medical therapy.

Therapeutic Femtosecond Laser-Assisted Lamellar Keratectomy for Multidrug-Resistant Nocardia Keratitis

PURPOSE

To describe the novel use of femtosecond laser technology for therapeutic resection of infectious foci in a case of multidrug-resistant Nocardia asteroides keratitis.

METHODS

A 30-year-old man presented with a corneal infiltrate. Cultures were taken, and fortified vancomycin and tobramycin were initiated. After 3 negative cultures and minimal improvement on various broad-spectrum antibiotics, all topical medications were stopped and a final fourth corneal culture grew N. asteroides. Treatment with topical amikacin was initiated, but the infection continued to worsen. With drug sensitivities still pending, the patient's clinical status continued to deteriorate rapidly, despite treatment with amikacin, gatifloxacin, and polymyxin B/trimethoprim. The femtosecond laser was then used to perform targeted lamellar keratectomy.

RESULTS

Femtosecond laser-assisted lamellar keratectomy successfully removed the infected tissue and allowed for increased penetration of topical antibiotics. Drug sensitivities finally returned, revealing multidrug resistance and sensitivity only to trimethoprim/sulfamethoxazole and tobramycin, some of which the patient had previously tried and failed. The infection fully resolved after readministering polymyxin B/trimethoprim and tobramycin, leaving minimal residual scarring.

CONCLUSIONS

Multidrug-resistant N. asteroides keratitis can be difficult to manage even with appropriate antibiotic therapy based on drug sensitivity testing. Femtosecond laser-assisted resections may facilitate treatment in these cases by safely and precisely debulking infected tissue and enhancing penetration of topical medications.

Nocardia Keratitis: A Case Report

Purpose

To describe a case of Nocardia keratitis resistant to 2% amikacin, with a toxic-allergic reaction to fortified topical 5% amikacin, and recurrence of the infection with topical corticosteroids.

Methods

Nocardia was diagnosed from a smear and positive culture and identified as Nocardia asteroides by gas chromatography and quantitative fatty acid analysis using the Microbial Identification System. Treatment was started with topical 2% amikacin, which was subsequently raised to 5% because of clinical resistance.

Results

A toxic-allergic reaction was observed after 5% amikacin so the drug was discontinued and commercially available drugs combining 1% chloramphenicol, 0.5% tetracycline, and 18 mil IU colistin with 0.3% ofloxacin were given. These were well tolerated and the infection improved quickly. After 1 month the antibiotics were discontinued and topical 0.1% clobetasone was given to reduce scar formation. The infection recurred after 1 week but responded to 3 months of the previous antibiotic combination and its sensitivity was checked with the Epsilometer test.

Conclusions

Nocardia keratitis may not respond to 2% topical amikacin and fortified topical 5% amikacin may cause a strong toxic-allergic reaction. A commercially available combination of chloramphenicol, tetracycline, and colistin, with ofloxacin, may be effective but the treatment must be continued for several months. Topical steroids should only be used with considerable caution since they can lead to relapse of the infection.

Nocardia infection following intraocular surgery: Report of seven cases from a tertiary eye hospital

PURPOSE

To study the outcome of ocular nocardiosis following intraocular surgery.

MATERIALS AND METHODS

A retrospective review of medical records of all postoperative cases of culture proven Nocardia infection over a period of 3 years, from October 2010 to September 2013, was performed. Microbiological analysis was performed for all cases and included smears and cultures. Fortified 2% amikacin eye drops were the mainstay of treatment. Surgical intervention was performed in case of nonresponse to medical therapy or suspected endophthalmitis.

RESULTS

Seven cases of culture proven Nocardia infection were seen. All cases had been operated in a hospital surgical facility. Six followed phacoemulsification, and one followed a secondary intraocular lens implantation. Four patients were part of a cluster infection. The mean duration between the primary surgical procedure and presentation was 16.14 ± 9.82 days. Five patients had infiltrates at the site of the surgical incision. One each had endophthalmitis and panophthalmitis. Six eyes required surgical intervention. Infection was seen to resolve in four eyes. Two eyes went into phthisis, and one was eviscerated. Only two of the six eyes, where in surgical intervention was performed early, obtained a final visual acuity of 20/60.

CONCLUSION

Early surgical intervention, before the involvement of the anterior chamber, may help preserve the anatomic and functional integrity of the eye.

Chronic Conjunctivitis due to Nocardia nova Complex Formation on a Silicone Stent: A Case Report and Review of the Literature

Nocardial conjunctivitis associated with silicone tubing is an extremely rare finding. The authors present a case of a 52-year-old woman with previous dacryocystorhinostomy and silicone tube placement 3 years prior who presented with OD redness and discharge for 1 week. On examination, the patient was noted to have mucoid discharge and crusting surrounding the silicone tube. The tube debris was sampled, and the culture was positive for Nocardia nova complex sensitive to trimethoprim/sulfamethoxazole and amikacin. Silicone tube colonization and N. nova complex conjunctivitis are both rare but should be considered in the differential diagnosis of patients with indwelling silicone tubes presenting with chronic conjunctivitis resistant to fluoroquinolones and tobramycin.

Case of keratitis caused by Streptomyces thermocarboxydus

We describe a case of keratitis caused by Streptomyces thermocarboxydus and report the usefulness of molecular analysis in identifying the exact species of Streptomyces. A 50-year-old man was diagnosed with keratitis caused by Streptomyces sp. which was identified as S. thermocarboxydus by sequencing the 16S rDNA. He had no history of trauma or systemic diseases. He was initially treated with topical beta-lactams and fluoroquinolones, and systemic beta-lactams but the keratitis did not improve. His vision improved significantly after topical erythromycin (5 mg/ml) and oral minocycline (200 mg/day) therapy. Our findings demonstrate that molecular analysis can be used to identify the exact Streptomyces species causing the keratitis. This then allowed us to determine the susceptibility of this species to different antibacterial drugs which were used to treat our patient successfully.

Contact lens-associated nocardial necrotizing scleritis

A 52 year-old, contact lens-wearing man presented with progressive right eye pain and redness for one month. He had been evaluated and treated for necrotizing scleritis by multiple eye care specialists prior to presentation. He underwent a complete systemic work-up for both autoimmune and infectious causes of scleritis, including a culture. The culture revealed heavy growth of Nocardia asteroides complexes. The patient was treated with topical amikacin and oral Bactrim. Following several weeks of antibiotic treatment, the patient's infection resolved completely, and his visual acuity returned to baseline status. Nocardia is a rare but potentially devastating cause of necrotizing scleritis that may affect contact lens wearers without an associated keratitis. Prompt recognition and early treatment with appropriate antimicrobial agents are critical to achieve a favorable outcome.

Update on pathologic diagnosis of corneal infections and inflammations

One of the most frequent types of corneal specimen that we received in our pathology laboratory is an excised corneal tissue following keratoplasty. Several of these cases are due to corneal infections or the sequelae, like corneal scar. Advances in the histological and molecular diagnosis of corneal infections and inflammations have resulted in rapid and accurate diagnosis of the infectious agent and in the overall understanding of the mechanisms in inflammatory diseases of the cornea. This review provides an update of histopathological findings in various corneal infections and inflammations.

A case of endophthalmitis associated with limbal relaxing incision

Limbal relaxing incisions (LRIs) are considered a relatively safe procedure with rapid stabilization and absence of infectious complications. Do we need to readdress this last impression? We report a case of nocardia endophthalmitis associated with an exudate at the site of an LRI in a patient who underwent routine cataract surgery. This case, to the best of our knowledge, is the first report of its kind, stressing the need for a cautious approach to the adoption of this method of astigmatic correction.

Management of post-operative Nocardia endophthalmitis

Post-operative Nocardia endophthalmitis has an aggressive course and poor visual prognosis. It often masquerades as severe post-operative uveitis or toxic anterior segment syndrome due to the absence of vitreous involvement resulting in a delay in diagnosis. The poor prognosis in Nocardia endophthalmitis is due to severe intra-ocular inflammation which may lead to phthisis. Therefore, treatment with corticosteroids after appropriate antibiotics have been initiated may improve the outcome. This is an interventional case report highlighting the typical features of Nocardia endophthalmitis, which when diagnosed early and managed medically with antibiotics and steroids, resulted in an excellent visual outcome in our patient.

Isolated Nocardia exalbida endogenous endophthalmitis

PURPOSE

To report an immunocompetent patient with Nocardia exalbida endogenous endophthalmitis.

DESIGN

Case report.

METHODS

Clinical-pathologic correlation and microbiologic evaluation were performed on an enucleated eye.

RESULTS

A 56-year-old man presented with rapidly progressive vision loss associated with a posterior choroidal mass and serous retinal detachment. Pathologic evaluation of the enucleated eye demonstrated endogenous endophthalmitis. Nocardia exalbida was identified microbiologically. Systemic workup failed to demonstrate definite foci of systemic infection or evidence of immunocompromise. Review of literature failed to identify previously reported cases of Nocardia exalbida endophthalmitis.

CONCLUSIONS

Nocardia can rarely cause isolated endogenous endophthalmitis in immunocompetent patients, which can contribute to a delay in diagnosis and vision loss. Endogenous Nocardia endophthalmitis typically occurs in immunocompromised patients with disseminated nocardiosis. Isolated endogenous Nocardia endophthalmitis in immunocompetent patients is rare. We describe isolated endogenous intraocular infection caused by Nocardia exalbida, a novel species, not previously associated with endophthalmitis.

Nocardia scleritis-clinical presentation and management: a report of three cases and review of literature

Aim

This study aims to describe the clinical features and management of Nocardia scleritis.

Methods

The authors retrospectively reviewed medical charts of three patients with microbiologically proven Nocardia scleritis and reviewed literature.

Results

All the patients presented with areas of well-demarcated, circumscribed abscess. No specific clinical feature could be attributed to the causative organism. Nocardia was identified by smear and culture from the scleral exudates. The medical management was based on the antibiotic sensitivity. Surgical exploration of the suppurated area along with the healthy margins was done on all patients. Two patients required multiple explorations. All three patients resolved with a good visual and tectonic outcome. The literature review also suggests a good outcome with prolonged medical management though the preferred antibiotic has changed over the years.

Conclusion

Though the prevalence of a disease like Nocardia scleritis is low, the results suggest that specific diagnosis and appropriate management can lead to a good outcome.

Etiology and antibacterial susceptibility pattern of community-acquired bacterial ocular infections in a tertiary eye care hospital in south India

AIMS

To identify the etiology, incidence and prevalence of ocular bacterial infections, and to assess the in vitro susceptibility of these ocular bacterial isolates to commonly used antibiotics.

MATERIALS AND METHODS

Retrospective analysis of consecutive samples submitted for microbiological evaluation from patients who were clinically diagnosed with ocular infections and were treated at a tertiary eye care referral center in South India between January 2002 and December 2007.

RESULTS

A total of 4417 ocular samples was submitted for microbiological evaluation, of which 2599 (58.8%) had bacterial growth, 456 (10.3%) had fungal growth, 15 (0.34%) had acanthamoebic growth, 14 (0.32%) had mixed microbial growth and the remaining 1333 (30.2%) had negative growth. The rate of culture-positivity was found to be 88% (P < 0.001) in eyelids' infection, 70% in conjunctival, 69% in lacrimal apparatus, 67.4% in corneal, 51.6% in intraocular tissues, 42.9% in orbital and 39.2% in scleral infections. The most common bacterial species isolated were Staphylococcus aureus (26.69%) followed by Streptococcus pneumoniae (22.14%). Sta. aureus was more prevalent more in eyelid infections (51.22%; P = 0.001) coagulase-negative staphylococci in endophthalmitis (53.1%; P = 0.001), Str. pneumoniae in lacrimal apparatus and corneal infections (64.19%; P = 0.001), Corynebacterium species in blepharitis and conjunctivitis (71%; P = 0.001), Pseudomonas aeruginosa in keratitis and dacryocystitis (66.5%; P = 0.001), Haemophilus species in dacryocystitis and conjunctivitis (66.7%; P = 0.001), Moraxella lacunata in blepharitis (54.17%; P = 0.001) and Moraxella catarrhalis in dacryocystitis (63.83%; P = 0.001). The largest number of gram-positive isolates was susceptible to moxifloxacin (98.7%) and vancomycin (97.9%), and gram-negative isolates to amikacin (93.5%) and gatifloxacin (92.7%).

CONCLUSIONS

Gram-positive cocci were the most frequent bacteria isolated from ocular infections and were sensitive to moxifloxacin and vancomycin, while gram-negative isolates were more sensitive to amikacin and gatifloxacin.

Nocardia farcinica Infection of a Baerveldt implant and endophthalmitis in a patient with a Boston type I keratoprosthesis

Eyes with implanted hardware carry a higher risk of infection. Here we report a rare case of Nocardia farcinica endophthalmitis and Baerveldt implant infection originating from infectious keratitis in a patient with a Boston type I keratoprosthesis. The infection resolved with aggressive surgical and medical treatment.

Nocardia keratitis

PURPOSE OF REVIEW

Nocardia keratitis is a rarity in most parts of the world. If the diagnosis is timely, and appropriate treatment started, then the visual outcome is good. The purpose of this review is to discuss the recently published literature in relation to the epidemiology, cause, diagnosis, and therapy of Nocardia keratitis.

RECENT FINDINGS

The incidence of Nocardia keratitis, although not well established, appears to be increasing with new species identified with newer molecular methods. The different species causing keratitis are Nocardia. arthritidis, N. neocaledoniensis, N. asiatica, N. asteroids type IV, N. brasiliensis, N. pseudobrasiliensis, N. cyriacigeorgica, N. farcinica, N. otitidiscaviarum, and N. transvalensis. Current therapies with fortified amikacin and newer fluoroquinolones are effective, provided the diagnosis has been made in good time. Ongoing research toward rapid diagnosis using various molecular techniques seems to be promising. Diagnostic microbiology laboratories need to be familiar with these organisms especially in endemic areas, and it is important for the clinician to notify the suspicion of such cases.

SUMMARY

The current recommended treatment is amikacin, and with appropriate therapy, Nocardia keratitis resolves with scarring, with or without vascularization, resulting in good visual outcome.

Outbreak of Nocardia keratitis after photorefractive keratectomy: clinical, microbiological, histopathological, and confocal scan study

Nocardia keratitis occurred in 4 eyes of 3 patients (2 women and 1 man) who had photorefractive keratectomy (PRK) by the same surgeon at the same center. Two eyes of the first 2 patients required lamellar keratectomy to debulk the involved stroma and obtain specimens for microbiological and histopathological evaluation. Light microscopic examination disclosed gram-positive and acid-fast filaments of Nocardia that were confirmed by the microbiological results. Diagnosis of Nocardia keratitis in the third case was not as challenging as in the first 2 cases because of a high index of suspicion. Confocal scans of all cases disclosed hyperreflective and slender, fibril-like structures in the corneal stroma. All eyes responded favorably to topical amikacin and the infection resolved without recurrence. The most probable cause of the outbreak was inadequate attention to sterility during surgery.

Bioadhesive sulfacetamide sodium microspheres: evaluation of their effectiveness in the treatment of bacterial keratitis caused by Staphylococcus aureus and Pseudomonas aeruginosa in a rabbit model

The aim of this study was to prepare bioadhesive sulfacetamide sodium (SA) microspheres to increase their residence time on the ocular surface and to enhance their treatment efficacy on ocular keratitis. Microspheres were fabricated by spray drying method using mixture of polymers such as pectin, polycarbophil and hydroxypropylmethyl cellulose (HPMC) at different ratios. The particle size and distribution, morphological characteristics, thermal behavior, encapsulation efficiency, mucoadhesion and in vitro drug release studies on formulations have been investigated. After optimisation studies, SA-loaded polycarbophil microsphere formulation with polymer:drug ratio of 2:1 was found to be the most suitable for ocular application and used in in vivo studies. In vivo studies were carried out on New Zealand male rabbit eyes with keratitis caused by Pseudomonas aeruginosa and Staphylococcus aureus. Sterile microsphere suspension in light mineral oil was applied to infected eyes twice a day. Plain SA suspension was used as a positive control. On 3rd and 6th days of the antimicrobial therapy, the eyes were examined in respect to clinical signs of infection (blepharitis, conjunctivitis, iritis, corneal oedema and corneal infiltrates) which are the main symptoms of bacterial keratitis and then cornea samples were counted microbiologically. The rabbit eyes treated with microspheres demonstrated significantly lower clinical scores than those treated with SA alone. A significant decrease in the number of viable bacteria in eyes treated with microspheres was observed in both infection models when compared to those treated with SA alone. In conclusion, in vitro and in vivo studies showed that SA-loaded microspheres were proven to be highly effective in the treatment of ocular keratitis.

Sutureless wound infection by unusual acid-fast organisms

PURPOSE

To report infection of self-sealing wounds in cataract surgery by unusual acid-fast organisms.

METHODS

Two patients who underwent phacoemulsification and developed corneal tunnel infection by acid-fast organisms were included. Both were managed with appropriate medical and surgical treatment modalities.

RESULTS

Diagnosis was facilitated in the first case by diagnostic and therapeutic lamellar keratoplasty and in the second case by the analysis of scrapings obtained from the inner lip of the tunnel. Ziehl-Neilsen staining helped diagnosis of acid-fast bacteria and implementation of adequate therapy. Nonresponse to appropriate susceptibility-guided medical therapy in the second case was controlled by timely surgical keratectomy as a peripheral patch graft.

CONCLUSIONS

Tunnel infection after phacoemulsification is a serious complication and can be caused by relatively uncommon acid-fast bacteria. Appropriate diagnostic work-up will help in the identification and institution of appropriate therapy.