Interface Scopulariopsis gracilis fungal keratitis following Descemet’s stripping automated endothelial keratoplasty (DSAEK) with a contaminated graft

Early postoperative infection following lamellar keratoplasty: a review

With the growing popularity of lamellar keratoplasty for selective replacement of diseased corneal tissue, it is important to understand the risk of developing an infection after the procedure. Although lesser than that postpenetrating keratoplasty, the reports on post lamellar keratoplasty infectious keratitis are not negligible. Trends of acute infections arising within 2 months of surgery are a subject of interest. Most of these infections are reported post Descemet's stripping endothelial keratoplasty with a preponderance of Candida species. A donor to host transmission of infection is not uncommon. Among the Candida cases, about 80% seem to occur due to a donor to host transmission. Infections presenting as or progressing to endophthalmitis lead to a poor visual outcome. Strict aseptic measures and protocols during corneal tissue harvesting, tissue processing, tissue storage and surgery are essential to prevent occurrence of these infections. After the infection has occurred, determining the aetiology and drug susceptibility through microbiological testing is vital. This helps to guide treatment protocols and hence determines final outcome of these cases. Most cases require some form of surgical management for resolution of infection, most often a graft removal and therapeutic keratoplasty. Secondary surgical interventions are performed to restore graft clarity and achieve a good final visual outcome.

Excisional penetrating keratoplasty for fungal interface keratitis after endothelial keratoplasty: surgical timing and visual outcome

PURPOSE

In this paper, we describe two cases of fungal interface infectious keratitis (IIK) developed after endothelial keratoplasty (EK) who underwent delayed therapeutic penetrating keratoplasty (TPK) with a poor visual outcome. Furthermore, we conducted a review of the literature and analyzed the visual outcomes of TPK in relation to the time from IIK diagnosis.

METHODS

We searched the literature for fungal IIK cases occurred after EK and treated by TPK. We identified 17 cases of fungal IIK, mostly caused by Candida spp. (88%).

RESULTS

Infection was diagnosed at a median time of 21 (range 1-90 days) days after EK. The median lag time between infection diagnosis and TPK was 30 (range 7-393) days. The median distance corrected visual acuity (DCVA) measured 4-12 months after surgery was 20/40 (range 20/200-20/20). When TPK was performed within one month from diagnosis, the final median DCVA was 20/30 (range 20/100-20/20), with 83% of patients achieving ≥ 20/40 vision. When TPK was carried out later, the final median DCVA was 20/50 (range 20/200-20/22) with 44% of patients achieving ≥ 20/40 vision. One patient in the early surgery and four patients in the late surgery group showed postoperative DCVA ≤ 20/100 despite clear grafts.

CONCLUSION

TPK with removal of the sequestered infection is advocated as a safe and effective measure to treat a post-EK infection. Early surgery allows a reduced exposure time to infection and therefore may result in better visual outcomes and lower risk of complications caused by prolonged inflammation.

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.

Interface infectious keratitis after anterior and posterior lamellar keratoplasty. Clinical features and treatment strategies. A review

Interface infectious keratitis (IIK) is a novel corneal infection that may develop after any type of lamellar keratoplasty. Onset of infection occurs in the virtual space between the graft and the host where it may remain localised until spreading with possible risk of endophthalmitis. A literature review identified 42 cases of IIK. Thirty-one of them occurred after endothelial keratoplasty and 12 after deep anterior lamellar keratoplasty. Fungi in the form of Candida species were the most common microorganisms involved, with donor to host transmission of infection documented in the majority of cases. Donor rim cultures were useful to address the infectious microorganisms within few days after surgery. Due to the sequestered site of infection, medical treatment, using both topical and systemic antimicrobials drugs, was ineffective on halting the progression of the infection. Injection of antifungals, right at the graft–host interface, was reported successful in some cases. Spreading of the infection with development of endophthalmitis occurred in five cases after Descemet stripping automated endothelial keratoplasty with severe sight loss in three cases. Early excisional penetrating keratoplasty showed to be the treatment with the highest therapeutic efficacy, lowest rate of complications and greater visual outcomes.