|Year : 2017 | Volume
| Issue : 5 | Page : 371-375
Nocardia infection following intraocular surgery: Report of seven cases from a tertiary eye hospital
Devesh Sharma, Umang Mathur, Abha Gour, Manisha Acharya, Nidhi Gupta, Neelam Sapra
Department of Cornea and Anterior Segment, Dr. Shroff's Charity Eye Hospital, New Delhi, India
|Date of Submission||29-Mar-2017|
|Date of Acceptance||31-Mar-2017|
|Date of Web Publication||2-Jun-2017|
Dr. Shroff's Charity Eye Hospital, 5027, Kedarnath Road, Daryaganj, New Delhi - 110 002
Source of Support: None, Conflict of Interest: None
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.
Keywords: Endophthalmitis, intraocular surgery, ocular infection, ocular nocardiosis
|How to cite this article:|
Sharma D, Mathur U, Gour A, Acharya M, Gupta N, Sapra N. Nocardia infection following intraocular surgery: Report of seven cases from a tertiary eye hospital. Indian J Ophthalmol 2017;65:371-5
|How to cite this URL:|
Sharma D, Mathur U, Gour A, Acharya M, Gupta N, Sapra N. Nocardia infection following intraocular surgery: Report of seven cases from a tertiary eye hospital. Indian J Ophthalmol [serial online] 2017 [cited 2019 Aug 21];65:371-5. Available from: http://www.ijo.in/text.asp?2017/65/5/371/207447
Nocardia is filamentous, Gram-positive, weakly acid–fast bacteria, frequently found as soil saprophytes. Ocular nocardiosis has most commonly been associated with infectious keratitis, with the reported incidence varying from 0.3% to 4.2%.,, Postoperative infections after intraocular surgical procedures caused by Nocardia are rare and potentially sight-threatening. Two series that studied the microbiological spectrum of endophthalmitis after intraocular surgery did not list Nocardia as a causative organism., The outcomes of Nocardia endophthalmitis have not been studied extensively, with only one large series on the subject, that reported a generally poor visual outcome. However, encouraging results have been noted in isolated case reports., The present retrospective analysis was conducted to evaluate the clinical outcomes of Nocardia infections after intraocular surgery.
| Materials and Methods|| |
We retrospectively reviewed the medical records of all postoperative cases of culture proven Nocardia infection that presented to our hospital over a period of 3 years, from October 2010 to September 2013. The parameters analyzed included predisposing factors, time between onset and presentation, presenting visual acuity, clinical examination, microbiologic data, antibiotic sensitivities of isolates, response to treatment, need for surgical intervention, time duration to surgical intervention from onset of symptoms, and the final best-corrected visual outcome.
At presentation, a complete ocular and systemic history was taken. A detailed slit-lamp evaluation was performed, and characteristics of the infiltrate were recorded, including the size, depth and location, and the height of the hypopyon, if present. B-scan ultrasonography was performed in case of suspected posterior segment involvement.
The type of sample taken for microbiological analysis depended on the clinical presentation of the case-corneal scraping, anterior chamber (AC) tap, or tissue biopsy. In the initial microbiology workup, samples were smeared onto glass slides for Gram stain and 10% potassium hydroxide wet mount preparations. Acid–fast staining was performed when Nocardia was suspected on Gram's stain. For culture, samples were plated onto blood agar, chocolate agar, brain-heart infusion broth, and on Sabouraud's dextrose agar. Blood agar, chocolate agar, and brain-heart infusion broth were maintained at 37°C for a period of 14 days. Sabouraud's dextrose agar was incubated at 26°C for 21 days. Growth of Nocardia species on culture was noted as chalky white colonies. This growth was then subjected to acid–fast staining and also subcultured on Lowenstein–Jensen media, which confirmed Nocardia. In case the culture was suspected to have growth of Nocardia, the smears that were initially stained with Gram's stain were destained with acetone and subjected to acid–fast staining, using 1% sulfuric acid. Antibiotic sensitivities of the isolates were obtained by the disc-diffusion method.
Amikacin eye drops (2%) were the mainstay of medical therapy once the causative organism was established. Surgical intervention was performed in case of nonresponse to medical therapy, or associated endophthalmitis. Patients were followed up every 24–48 h in the first week, 2–3 times a week for the next 2 weeks, and then weekly for a month.
| Results|| |
Over a 3-year period from October 2010 to September 2013, seven patients were diagnosed with culture-positive Nocardia infection after intraocular surgery. The mean age was 58.71 ± 10.05 years (age range: 35–68 years). There were four male and three female patients. Three patients were diabetics under treatment. All seven patients were operated on in a hospital surgical facility. One case followed an in-house surgery while six patients were referred from elsewhere. Four patients were part of a cluster infection, having had phacoemulsification on a single day in the same operation room. However, these patients were referred to our hospital at different times, and so the severity of presentation differed. Out of the seven cases, six followed phacoemulsification with intraocular lens (IOL) implantation and one followed secondary IOL surgery for aphakia. All the infections were predominantly wound infections with intra-ocular extension, presumably due to the reuse of the surgical blades.
The time interval between the surgical procedure and presentation varied from 7 to 30 days (mean = 16.14 ± 9.82 days). One patient had undergone core vitrectomy elsewhere, for associated endophthalmitis 2 weeks before presentation. Visual acuity at presentation ranged from 20/30 to no light perception.
On clinical examination, five patients were seen to have infiltrate at the site of the surgical incision. The infiltrates appeared fluffy, dense, frequently involved the deep corneal stroma, had a yellowish tinge and had fairly well-defined margins with a limited zone of surrounding edema [Figure 1]. In addition, frank exudation in the AC was seen in two patients, one of which had a localized exudate on the iris. One patient showed associated involvement of the vitreous cavity on B-scan ultrasonography in the form of multiple dot and membrane echoes and was diagnosed with endophthalmitis [Figure 2]. A diagnosis of panophthalmitis was made in one patient who had restricted ocular motility, posterior segment involvement on ultrasound, and denied light perception. One patient presented with a gradually progressive diminution of vision and scleral nodules with an associated exudative retinal detachment [Figure 3]. In four cases, an initial clinical impression of fungal infection was made.
|Figure 1: Deep corneal stromal infiltrates at the surgical incision sites in case 3 (a). (b) Following corneal patch grafts|
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|Figure 2: Exudation in the anterior chamber in case 2. B-scan ultrasonography showed involvement of the vitreous cavity|
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|Figure 3: Multiple scleral nodules in case 7. Fundus evaluation revealed an associated exudative retinal detachment|
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Samples from all seven patients were subjected to microbiological analysis [Figure 4]. Three patients underwent early surgical intervention, within 8 days of onset of symptoms, and samples from surgery were sent for microbiological analysis. The samples included contents of evisceration sample (1), scleral biopsy (1), and corneal button (5). Direct microscopic examination with 10% acid–fast staining was performed in only four samples, and Nocardia could be detected in two (50%) of these on microscopy.
|Figure 4: Smears on potassium hydroxide media revealing Nocardia organisms (×2) (a). Nocardia colonies on blood agar (b)|
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All the samples sent for culture grew Nocardia. Chalky white, tiny colonies of Nocardia grew on blood agar, chocolate agar, and Sabaroud's dextrose agar in 48 h in all patients. Cultures also revealed an Aspergillus coinfection in one patient. Antibiotic sensitivity testing was performed in all the samples. All samples were sensitive to amikacin. Antibiotic sensitivity testing could be performed in six of the seven samples. The antibiotic sensitivity report showed sensitivity to amikacin (7/7), moxifloxacin (5/7), gatifloxacin (5/7), ciprofloxacin (6/7), gentamicin (6/7), tobramycin (4/7), imipenem (4/7), and linezolid (3/7).
Six of the seven cases (85.71%) required some form of surgical intervention-evisceration (1), therapeutic penetrating keratoplasty (1) [Case 6, Figure 5], corneal patch graft (2), core vitrectomy with corneal patch graft (1), and scleral patch graft (1) [Figure 6]. The time duration between the onset of symptoms and surgical intervention varied from 7 to 42 days.
|Figure 5: Multiple deep infiltrates and corneal perforation (a) in case 6. (b) Anterior chamber exudation. (c) Following therapeutic penetrating keratoplasty|
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|Figure 6: Scleral patch graft (a) for a scleral abscess in case 1. Three months postoperatively, the eye is quiet (b)|
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Infection was seen to resolve in four out of the seven patients. Surgical intervention was performed within a week of onset of symptoms in the two cases [Case 3 - Figure 1 and Case 5 - Figure 7]. The summary as well as outcomes of all the cases is tabulated in [Table 1].
|Table 1: Demography, risk factors, clinical presentation, management, and outcomes of subjects|
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|Figure 7: Endoexudate at the corneal surgical incision in case 5 (a). Following a corneal patch graft (b)|
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| Discussion|| |
Our case series of Nocardia infection following ocular surgery suggests that patients with early surgical intervention had a better prognosis than cases that had delayed intervention. In addition, surgery performed in the absence of significant intraocular involvement, translated into better visual outcomes. This emphasizes the need for prompt microbiological diagnosis and surgical intervention for Nocardia infections. All cases in our study had involvement of the deep corneal stroma, with or without intraocular extension, where medical therapy may be ineffective. Corneal scraping may not be possible in most cases due to nonavailability of surface infiltration, making it difficult to initiate treatment based on microbiology findings.
Postoperative infections caused by Nocardia species are generally regarded as uncommon., However, an unusually high rate (16.8%) of postoperative infections caused by the organism has been found in South India. This may be relevant for tropical regions. In the same series, only three cases (12.5%) of infection followed phacoemulsification surgery. In addition, there were no cases that occurred as a cluster infection. Four cases in our study were part of a cluster infection. All four cases had infection at the incision site with varying severity of anterior and posterior segment involvement, depending on the time of presentation. Gokhale et al. have reported two cases of infection following phacoemulsification from a surgical knife that was not resterlized. Five of our seven patients (including four from the cluster infection) had surgical site infection from possibly infected surgical knives. Nocardia is found to be endemic in soil and dust and may infect hospital spaces. Contamination of surgical instruments and reuse with improper sterilization may lead to Nocardia infection. Most of the cases had their primary surgery elsewhere and were referred to us for the management of postoperative infection, and hence, we were unable to perform root cause analysis of the infection in the operative field.
Medical therapy may only be successful for superficial Nocardia infections. When infection is deep seated, treatment failure is likely. Poor response to medical therapy may be found even when isolates are found to be sensitive in vitro. Gokhale et al. found good outcomes with early surgical intervention. Two patients, in our study, who had deep infiltrates limited to the site of the surgical incision, without significant anterior segment involvement, also benefited from early surgery and maintained a visual acuity of at least (20/60). In addition, surgical intervention may provide opportunity to obtain material for microbiological examination in deep-seated infection. Four of the total seven (57.14%) patients had a final visual acuity of hand motions or worse. This may be due to the advanced nature of the infection at presentation. Nocardia infections have generally been associated with a poor visual outcome. The absence of posterior segment involvement may not necessarily give the patient a better prognosis. It has been hypothesized that extensive involvement of the AC and ciliary body may result in hypotony and phthisis bulbi. Indeed, two patients in the present study, without a posterior segment involvement, had a poor visual outcome.
| Conclusion|| |
Nocardia infections after intraocular surgery have a guarded visual prognosis. Early surgical intervention, before the involvement of the AC, may help preserve the anatomic and functional integrity of the globe.
Authors would like to thank Mr. Lokesh Chauhan for analytical and technical assistance.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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