Donor to host transmission of disease via corneal transplantation

Quality assurance in corneal transplants: Donor cornea assessment and oversight

The cornea is the most frequently transplanted human tissue, and corneal transplantation represents the most successful allogeneic transplant worldwide. In order to obtain good surgical outcome and visual rehabilitation and to ensure the safety of the recipient, accurate screening of donors and donor tissues is necessary throughout the process. This mitigates the risks of transmission to the recipient, including infectious diseases and environmental contaminants, and ensures high optical and functional quality of the tissues. The process can be divided into 3 stages: (1) donor evaluation and selection before tissue harvest performed by the retrieval team, (2) tissue analysis during the storage phase conducted by the eye bank technicians after the retrieval, and, (3) tissue quality checks undertaken by the surgeons in the operating room before transplantation. Although process improvements over the years have greatly enhanced safety, quality, and outcome of the corneal transplants, a lack of standardization between centers during certain phases of the process still remains, and may impact on the quality and number of transplanted corneas. Here we detail the donor screening process for the retrieval teams, eye bank operators. and ophthalmic surgeons and examine the limitations associated with each of these stages.

Occurrence of Herpes Viruses in Morphologically Normal Corneas

PURPOSE

The purpose of this study was to detect the occurrence of herpes simplex virus (HSV) types 1 and 2 and varicella zoster virus (VZV) DNA in transplanted corneas using polymerase chain reaction (PCR) and to determine the relationship between latent HSV and VZV and herpetic eye disease in recipients.

METHODS

This was a retrospective, interventional case series. Samples from 88 donor corneoscleral buttons (CSBs) were collected from the conjunctiva, iris, and endothelium and tested for HSV-1, HSV-2, and VZV DNA using PCR. All transplanted eyes were evaluated and followed up. The main outcome measures were HSV-1, HSV-2, and VZV DNA positivity rates in donor CSBs and the occurrence of herpetic eye disease or graft failure in recipients of positive corneas.

RESULTS

HSV-1 DNA was detected in 5 (5.7%) of 88 CSBs. HSV-2 was not detected in any CSBs, and VZV was found in 1 (1.2%) of the 82 examined CSBs. One recipient (16.7%) developed dendritic epitheliopathy and keratouveitis typical of HSV 12 months after transplantation, although the graft remained clear after treatment. One cornea was used for a tectonic graft and stayed edematous at the 20-month follow-up. The remaining corneas remained clear.

CONCLUSIONS

Morphologically normal donor corneas may be PCR-positive for herpes viruses, especially HSV-1. Recipients of herpes-positive corneal grafts could be at risk for herpetic eye disease. Further studies using viral RNA by reverse transcriptase PCR are needed to provide more information on HSV and VZV latency and active replication in donor corneas.

Hospital Cornea Retrieval Programme in a startup eye bank - A retrospective analysis and lessons learned

Purpose:

This study aimed to share our experience in the hospital cornea retrieval program as a new eye bank.

Methods:

This was a retrospective study conducted in a tertiary care institute from August 26, 2019 to March 22, 2020. The medical and eye bank records were analyzed for hospital mortality, mortuary records, and donors approached. The corneal collection was divided between Voluntary (received from voluntary calls), HCRP (cornea received from hospital deaths), and Medico-Legal Cases (received from MLC deaths in hospital) to see the trend of donation and utilization over time.

Results:

During the study period, 154 corneas (77 pairs) were collected. The HCRP provided a major source of corneas 58.4% (90 corneas) as compared to voluntary 19.5% (30 corneas) and MLC 22.1%(34 corneas). There were younger tissues in MLC than HCRP donors, and older tissues in Voluntary donors, and the difference was statistically significant. There was no significant difference in the quality of optical grade tissues and the utilization of corneas for transplants between the three groups. Post hoc analysis showed more non-optical tissues in the voluntary donations (P = 0.004), maximum donors with medical contraindications in the HCRP group (P = 0.001), and time-lapse in corneal retrieval in MLC cases (P = 0.0001). Of these 154 corneas, 78 (50.6%) were assessed as suitable for transplantation, of which 59 (75.6%) tissues were optical grade tissues. The overall utilization was 39.6%.

Conclusion:

HCRP is indeed challenging for a new eye bank, but proper understanding and implementing strategies may help for good utilization of tissues.

Distribution of Microbial Keratitis After Penetrating Keratoplasty According to Early and Late Postoperative Periods

Objectives:

The aim of this study was to investigate the distribution of microbial agents in the early and late postoperative periods in patients with microbial keratitis (MK) after penetrating keratoplasty (PK).

Materials and Methods:

The records of 36 patients who were clinically diagnosed as having MK after PK were retrospectively reviewed. Culture results were obtained from microbiology records and the organisms that were produced were noted. A case was deemed as viral keratitis based on the clinical appearance, negative cultures, and response to antiviral treatment. Keratitis development times were evaluated in 2 categories: early (within the first year) and late (after year 1) postoperative period. Mann-Whitney U and Kruskal-Wallis tests were used to compare numerical variables that did not show normal distribution and chi-square test was used to compare categorical variables.

Results:

The majority of MK cases were of bacterial origin (55.5%, n=20), followed by viral (41.7%, n=15) and fungal (2.8%, n=1). Of the 15 cases of early postoperative MK, 10 were bacterial, 4 were viral, and 1 was fungal; however, among cases of late postoperative MK, 10 were bacterial and 11 were viral. The majority (65%) of early and late bacterial infections were caused by gram-positive strains (most commonly staphylococci). Gram-positive bacteria caused keratitis significantly earlier than gram-negative bacteria (p=0.037). Viral and gram-negative bacterial MK was more frequent in the late postoperative period, but the difference was not statistically significant.

Conclusion:

In our study, bacterial keratitis was more common in post-keratoplasty MK than viral and fungal keratitis. Gram-positive bacteria were the most common causative agents. The increased incidence of gram-negative bacterial agents and viral keratitis in the late postoperative period can be explained by long-term topical steroid use.

Infectious Disease Transmission through Cell, Tissue, and Organ Transplantation: Reducing the Risk through Donor Selection

The incidence of cell transplant-transmitted infection is unknown and can only be inferred from prospective studies–that have not yet been performed and reported. The possibility of donor-to-recipient disease transmission through cell transplant therapy can be considered by reviewing the risk associated with other transplanted tissues and organs. Viral, bacterial, and fungal infections have been transmitted via transplantation of organs, tissue allografts such as bone, skin, cornea, and heart valves, and cells such as islets, hematopoietic stem cells, and semen. Several types of protozoan and worm parasites have been transferred via organ transplants. Bone allografts have transmitted hepatitis, tuberculosis, and human immunodeficiency virus (HIV-1). Corneas have transmitted rabies, Creutzfeldt-Jakob disease (CJD), hepatitis B (HBV), cytomegalovirus (CMV), herpes simplex virus (HSV), bacteria, and fungi. Heart valves have been implicated in transmitting tuberculosis and hepatitis B. HIV-1 and CMV seroconversion has been reported in patients receiving skin from seropositive donors. CJD has been transmitted by dura and pericardium transplants. Over the past several years, improvements in donor screening criteria, such as excluding potential donors with infection and those with behaviors risky for HIV-1 and hepatitis infection, and introduction of new donor blood tests have greatly reduced the risk of HIV-1 and hepatitis and may have nearly eliminated the risk of tuberculosis and CJD. Prior to use, many tissues are exposed to antibiotics, disinfectants, and sterilants, which further reduce or remove the risk of transmitted disease. Because organs, cells, and some tissue grafts cannot be subjected to sterilization steps, the risk of infectious disease transmission remains and thorough donor screening and testing is especially important.

Eye banking and corneal transplantation communicable adverse incidents: current status and project NOTIFY

PURPOSE

Evidence of the transmission of disease via donor ocular tissue has been demonstrated for adenocarcinoma, rabies, hepatitis B virus, cytomegalovirus, herpes simplex virus, Creutzfeldt-Jakob disease, and a variety of bacterial and fungal infections.

METHODS

Although there is no evidence to date of disease transmission for HIV infection, syphilis, hepatitis C, hepatitis A, tuberculosis, HTLV-1 and -2 infection, active leprosy, active typhoid, smallpox, and active malaria, these entities remain contraindications for transplantation for all eye banks nationally and internationally. The potential sources of contamination include infected donors, during the process of removing tissue from cadaveric donors, the processing environment, and contaminated supplies and reagents used during processing. The transmissions of Herpes simplex virus and HSV via corneal graft have been shown to be responsible for primary graft failure. HSV-1 may also be an important cause of PFG.

RESULTS

The long latency period of some diseases, the emergence of new infectious disease, and the reemergence of others emphasize the need for long-term record maintenance and effective tracing capabilities.

CONCLUSIONS

The standardization of definitions for adverse events and reactions will be necessary to support the prevention and transmission of disease. International classification of a unique identification system for donors will be increasingly important for vigilance and traceability in cross-national exportation of human cells, tissues, and cellular- and tissue-based products. Opportunities for continuous improvement exist as does the need for constant vigilance and surveillance.

Frequency of positive donor rim cultures after penetrating keratoplasty using hypothermic and organ-cultured donor corneas

PURPOSE

To compare the frequency of positive rim cultures after penetrating keratoplasty using corneas preserved by hypothermic and organ culture storage. To evaluate the influence of standard procurement techniques on the frequency of microbial donor rim contamination.

METHODS

Six hundred four donor corneas stored at 31 degrees C and 214 at 4 degrees C were studied. Microbiology studies were carried out during organ culture storage, and corneas with positive medium cultures were discarded. Frequency of postoperative positive rim cultures was related to the type of corneal storage and procurement technique used.

RESULTS

Thirty-nine (6.4%) corneas with positive medium cultures were discarded during organ culture. Microbiology reports of 628 donor rims cultures from 671 (94%) consecutive transplants were reviewed. Positive rim cultures resulted in 24 (3.8%) cases. None of the patients developed endophthalmitis. The frequency of postoperative positive rim cultures was greater after hypothermic than organ culture storage, being 9.8% and 1.3%, respectively (chi(2) = 24.9; P < 0.001). With organ culture storage, the frequency of positive rim cultures was 1.3% and 1.4% after enucleation and in situ corneal excision, respectively (chi(2) = 0.03; P = 0.638). After hypothermic storage, positive rim cultures were found in 8% of the corneas procured using enucleation and 12% of the corneas excised in situ (chi(2) = 0.829; P = 0.254).

CONCLUSIONS

Organ culture storage allows one to recognize and discard corneas with microbial contamination during storage. This method significantly reduces the frequency of postoperative positive rim cultures compared with hypothermic storage. Procurement methods do not influence the percentage of positive rim cultures.

Infectious keratitis following keratoplasty

Infectious keratitis following corneal transplantation is one of the leading causes of failure of a corneal graft. The incidence of graft infection is variable, with developing countries having a higher incidence. The majority of the graft infections occur within 1 year of the corneal transplantation. Suture-related problems and persistent epithelial defect are the most common risk factors predisposing to graft infection. Pneumococcus species and Staphylococcus aureus have been found to be the commonest microorganisms in the developed world, whereas Staphylococcus epidermidis is the most often detected microorganism in corneal graft infection in the developing world. The early identification of predisposing risk factors in patients and their appropriate management at the earliest may prevent the occurrence of graft infection and might improve graft survival. Visual prognosis in eyes with post-keratoplasty graft infection is poor even after optimal therapy and there is a high rate of graft decompensation.

Bacterial infection transmitted by human tissue allograft transplantation

Bacterial contamination of tissue allografts obtained from cadaveric donors has been a serious cause of morbidity and mortality in recipients. Recent cases of fatal and nonfatal bacterial infections in recipients of contaminated articular cartilage (distal femur) and tendon allografts have called attention to the importance of avoiding tissue donors suspected of carrying infectious disease, of not processing donated tissue carrying virulent bacteria, the occurrence of falsely negative final sterility tests, and the need to sterilize tissues. These cases demonstrated that contamination can arise from an infected donor, during tissue removal from cadaveric donors, from the processing environment, and from contaminated supplies and reagents used during processing. Final sterility testing can be unreliable, especially when antibiotics remain on tissues. There is an increasing need for control of microbial contamination in tissue banks, and sterilization of tissue allografts should be recommended whenever possible.

The Efficacy of Postenucleation Saline Wash and the Effect of Different Antimicrobial Agents on Microbial Contamination of Donor Eyes

OBJECTIVES

To evaluate the efficacy of postenucleation saline wash and the effect of different antimicrobial agents on the microbial contamination of donor eyes.

METHODS

Two hundred donor eyes were given saline wash and treated with any one of the following 5 randomly selected antimicrobial solutions: 1% povidone-iodine for 3 min, 0.3% gentamycin for 10 min, 0.3% ciprofloxacin for 10 min, a combination of neomycin 1,700 IU, gramicidin 0.025% and polymyxin B 5,000 IU (Neosporin(R)) for 10 min and a combination of 0.3% amikacin for 10 min, followed by 2.5% cefazolin for 10 min. Limbal swabs were sent for culture before and after saline wash and after treatment with antimicrobial agents.

RESULTS

On culture of the pretreatment swabs, 77.5% were positive for growth with 75.5% bacterial and 11.5% fungal. Coagulase-negative Staphylococcus (29.1%) was the most common bacterial contamination followed by Pseudomonas aeruginosa (18.5%), Acinetobacter sp. (18.5%) and Alcaligenes faecalis (13.2%). A 20-ml sterile saline wash resulted in a 20% decrease (p < 0.01) in the amount of contamination. The maximum antimicrobial effect with regard to bacterial decontamination was achieved with povidone-iodine (64% decrease in the amount of contamination, p < 0.01) followed by ciprofloxacin (47.6% decrease, p < 0.05), the combination of cefazolin and amikacin (42.5%, p < 0.05), Neosporin (38.5%, p < 0.05) and then gentamycin (21.7%, p = NS).

CONCLUSIONS

A thorough saline wash and treatment with 1% povidone-iodine for 3 min is a more effective method for the decontamination of donor eyes as compared to most currently available and frequently used antibiotics.

Cryptococcus albidus keratitis after corneal transplantation

PURPOSE

To report suspected donor-to-host transmission of Cryptococcus albidus after penetrating keratoplasty.

METHODS

Review of the literature and a case report of a 69-year-old woman who underwent penetrating keratoplasty for Fuchs corneal dystrophy and developed persistent corneal infiltrates 7 months postoperatively are presented.

RESULTS

Cryptococcus albidus was cultured from the original donor tissue at the time of the repeat keratoplasty.

CONCLUSION

This case demonstrates an unusual case of cryptococcal keratitis after keratoplasty suspected to be a donor-to-host transmission.

Organ-cultured corneal grafts from septic donors: a retrospective study

PURPOSE

To evaluate the quality of corneal grafts from donors, who have died from septic multi-organ failure and who are called septic donors in the following.

METHODS

One hundred and eighty-two corneal grafts from septic donors were stored in organ culture for 10-14 days. Graft evaluation was performed according to the criteria of the European Eye Bank Association. Only donor corneas with cell density values above 2000 cells/mm(2) were transplanted. Ninety-one patients who received these transplanted corneas were examined retrospectively with special emphasis on endophthalmitis, graft failure and incidence of immune reactions.

RESULTS

Ninety-one of 182 donor corneas (50%) from septic donors were discarded mainly due to endothelial damage (61; 67%). Only seven (8%) were discarded due to medium contamination. In contrast, 452 of 1261 donor corneas (36%) from non-septic donors during the same period were discarded, again mainly due to endothelial damage (264; 58%). In this group, 48 donor corneas (11%) were discarded due to medium contamination. No patient who had received a graft from a septic donor has experienced endophthalmitis. The rate of immune reactions and graft failure was in the same range when compared to a larger group who received grafts from non-septic donors.

CONCLUSION

Our data reveal no contraindication against the use of corneal grafts derived from septic donors, critical graft assessment in organ culture provided.

Donor-to-host transmission of Candida albicans after corneal transplantation

PURPOSE

To report donor-to-host transmission of Candida albicans after penetrating keratoplasty.

DESIGN

Interventional case report.

METHODS

A 15-year-old boy who underwent penetrating keratoplasty for keratoconus with donor tissue from a drowning victim developed keratitis and a lenticular abscess 26 days postoperatively.

RESULTS

Candida albicans was cultured from the donor rim and the recipient cornea. Antifungal sensitivity profiles were identical for the two isolates. DNA profiles were identical for both isolates, confirming the donor as the source of the infection.

CONCLUSION

This case demonstrates the value of routine culture of corneal donor rims and the advisability of close follow-up and possible antifungal prophylaxis when donor rims are positive for fungus.

Detection of hepatitis C virus in the corneas of seropositive donors

PURPOSE

There have been no reported cases of hepatitis C virus (HCV) transmission by corneal transplantation. Previous studies have also shown no correlation between HCV seropositivity and the presence of HCV RNA in the corneal tissues. This study aims to investigate such correlation and to provide further evidence to the possible transmissibility of HCV via corneal grafts.

METHODS

Of the 1,619 potential corneal donors to the Eye Bank of Canada over a 1-year period, 15 tested HCV-positive by the second-generation Abbott HCV enzyme immunoassay (EIA) 2.0 assay. Their sera were further tested with second-generation radio-immunoblot assay (RIBA-II), and their corneas (29 altogether) were processed for identification of HCV RNA using polymerase chain reaction (PCR).

RESULTS

Of the 29 corneas from seropositive donors, HCV RNA was detected in 7 (24.1%).

CONCLUSION

This is the first study in the literature that demonstrates a significant correlation between HCV seropositivity and the presence of HCV in the corneas. Routine HCV serologic testing for all potential corneal donors and rejection of corneal tissues based on HCV seropositivity is certainly justifiable.

The past twenty-five years in eye banking

PURPOSE

This review of milestones and challenges in eye banking describes efforts made by dedicated eye bankers to ensure the quality and quantity of corneal tissue for corneal blind patients over the last 25 years.

METHODS

This account is the result of the recollection of the author, discussions with eye bankers, and a review of the literature, public documents, and Eye Bank Association of America (EBAA) records.

RESULTS

A measure of the success of eye banking is the fact that corneal transplant surgery is now scheduled as an elective procedure. Corneal tissue has also enjoyed a stellar safety record. This is due in part to the establishment of comprehensive medical standards by the EBAA, the accreditation of eye banks, and the training and certification of eye bank technicians.

CONCLUSION

Advancements in eye banking over the last 25 years have improved the quality of life of several hundred thousand corneal blind persons in this country. More efforts must be made in the future to eliminate corneal blindness internationally.

Aspergillus terreus postoperative endophthalmitis

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Candida tropicalis endophthalmitis following penetrating keratoplasty

A case of Candida tropicalis endophthalmitis following penetrating keratoplasty is presented. The donor was an alcoholic, who died of bronchopneumonia and pancreatitis. We presume the candida infection was transmitted by the donor because Candida tropicalis was cultured in life from the donor's throat swab and corresponding fungal elements were discovered post mortem in kidney sections of the donor.

Unsuspected infectious keratitis in host corneal buttons

Infectious keratitis may be unsuspected preoperatively in patients undergoing penetrating keratoplasty. We have diagnosed five cases of previously unknown corneal infection discovered only after post-keratoplasty histopathologic examination using specific stains. These cases of preoperatively unsuspected infectious keratitis illustrate examples where histopathologic examination using specialized stains may alert the physician to the need for appropriate postoperative antimicrobial therapy. Furthermore, these cases illustrate the ability of soft contact lenses to mask symptoms of infectious keratitis. Additionally, the clinical appearance of advanced bullous keratopathy may mask signs of infectious keratitis.

Corneal preservation

Significant advances in corneal preservation have been made over the past decade. The introduction of chondroitin sulfate-containing media for use at 4 degrees C allows storage of corneas for up to ten days prior to transplantation. Organ culture techniques have also been improved with the addition of chondroitin sulfate. There has been an increase in our understanding of preservation using McCarey-Kaufman medium. Studies have been published that compare these methods and help the clinician decide which method to use based on objective data. Also, our understanding of existing methods of evaluating endothelial viability has increased and new methods have been developed. Finally, the acquired immunodeficiency syndrome is having an increasing effect on eye-banking and the supply of donor corneas.

Corneo-scleral rim cultures: donor contamination a case of fungal endophthalmitis transmitted by K-Sol stored cornea

This retrospective study of 549 corneo-scleral rim cultures shows that gentamicin, used in MK and K-Sol medium storage at 4 degrees C, has decreased donor contamination from 43% in whole-globe storage to 13%, but failed to eliminate coagulase negative staphylococci (37%), streptococci (28%) and fungi (28%). Donor-to-host transmitted staphylococcal and streptococcal endophthalmitis have been reported previously. We present the first documented case of donor-to-recipient transmitted fungal endophthalmitis following corneal transplantation using corneas stored in MK or K-Sol solution at 4 degrees C; Candida albicans was isolated. Recommendations are made to assess critically the true incidence of donor fungal contamination and the necessity of adding anti-mycotic agents to preservation medium for 4 degrees C storage. In the absence of ideal antimicrobial cover for corneal preservation solutions, stringent prophylactic measures to reduce contamination and continued monitoring of corneo-scleral rim cultures are warranted, if the poor visual consequences of donor-to-host transmitted endophthalmitis are to be avoided.

Effectiveness of a decontamination method for donor corneas

A retrospective study was made of the effectiveness of an eye bank decontamination and storage method. A comparison was made between microbial cultures taken from the limbus at enucleation and from scleral remnants recovered after surgery. Organisms were isolated from the limbus of 73% of donor eyes and from 4% of remnants. Standard eye bank procedures were found to eradicate gut and skin organisms, including candida, from donor tissue.

Hepatitis B surface antigen in corneal donors

Using an enzyme immunoassay, we detected hepatitis B surface antigen in washings of ocular tissue from two of three corneal donors who had positive serum assays for hepatitis B surface antigen. Hepatitis B surface antigen was identified in emulsified corneal tissue from one of two donors from whom corneal tissue was available for study.

Candida albicans endophthalmitis after penetrating keratoplasty

We examined two patients who received contaminated corneas from the same organ donor during penetrating keratoplasty. Both developed Candida albicans endophthalmitis, which responded to surgical and antifungal therapy. On follow-up examination one patient had a visual acuity of hand motions, a pupillary membrane, and a macular scar. The other had a visual acuity of 20/100 and a clear graft.

Survival of corneal grafts from donors supported by mechanical ventilation

Eighty-five patients undergoing penetrating keratoplasty with tissue from donors supported by mechanical ventilation (Ventilator group) were compared to a surgeon- and diagnosis-matched group (Control group). Age at surgery, duration of follow-up, and sex of recipient patients were similar in the two groups. The mean donor age in the Ventilator group (26.4 years) was significantly less than in the Control group (45.8 years, P less than 0.0001). Mean time on the ventilator was 99.4 hours (range, 4 hours to 21 days). Overall graft survival rates in the Ventilator and Control groups were similar (P greater than or equal to 0.72). Time on the ventilator did not affect graft survival. Cultures of corneoscleral donor rims were positive more often in the Ventilator group than in Controls (39.7 versus 23.1%), but the difference was not significant (P = 0.09). Prolonged ventilator time was not associated with a higher rate of positive corneoscleral rim cultures, nor did positive cultures affect graft survival. The most common cause of graft failure in both groups was allograft rejection. In no case could postoperative bacterial infection be attributed to contamination of the donor material. One case of primary donor failure occurred in the Ventilator group, but the incidence (1.2%) is similar to that of previously reported studies. The data indicate that corneal tissue from ventilator-supported donors should be considered for use in penetrating keratoplasty.

Contamination of donor cornea by gentamicin-resistant organisms

Cultures of the donor corneoscleral rims in 70 consecutive penetrating keratoplasties showed microbial contamination in 14 cases. All positive cultures were tested by standard microdilution broth method for sensitivities to gentamicin, an antibiotic routinely used in McCarey-Kaufman transport medium. Seven of 15 organisms demonstrated resistance to gentamicin at concentrations above 100 micrograms/ml. These results indicated the selection of more antibiotic-resistant microorganisms in antibiotic-supplemented medium and the need for appropriate antibiotic prophylaxis at the time of surgery.