Incidence and clinical significance of bacterial and fungal contamination of the preservation solution in liver transplantation

Assessing the impact of positive cultures in preservation fluid on renal transplant outcomes: a scoping review

BACKGROUND

Infection following kidney transplantation is a significant risk factor for adverse outcomes. While the donor may be a source of infection, microbiological assessment of the preservation fluid (PF) can mitigate potential recipient contamination and help curb unnecessary antibiotic use. This scoping review aimed to describe the available literature on the association between culture-positive preservation fluid, its clinically relevant outcomes, and management.

METHODS

Following the Joanna Briggs Institute's scoping review recommendations, a comprehensive search in databases (EMBASE, MEDLINE, and gray literature) was conducted, with data independently extracted by two researchers from selected studies.

RESULTS

We analysed 24 articles involving 12,052 samples, predominantly published post-2000, 91% of which retrospective. The prevalence of culture-positive preservation fluid varied from 0.86 to 77.8%. Coagulase-negative staphylococci emerged as the most frequently isolated pathogen in 14 studies. The presence of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), observed in two studies involving 1074 donors, was significantly associated with an increased risk of probable donor-derived infections (p-DDI). Of the reviewed articles, 14 reported on probable donor-derived infections, while 19 addressed the topic of preemptive antibiotic therapy.

CONCLUSIONS

Routine culturing of preservation fluid is crucial for the identification of pathogenic organisms, facilitates targeted treatment and prevents probable donor-derived infections. Furthermore, this approach helps avoid the treatment of low-virulence contaminants, thereby reducing unnecessary antimicrobial use and the risk of antibiotic resistance. In cases where ESKAPE or Candida species are detected, preemptive therapy appears to be an important strategy. Given that the current evidence primarily stems from retrospective studies, there is a pressing need for large-scale, prospective trials to corroborate these recommendations. This scoping review currently represents the most thorough compilation of evidence on how contamination of preservation fluids affects kidney transplant management.

Utility of deceased donor cultures in solid organ transplantation in preventing donor-derived bacterial and fungal infectious diseases transmission

Deceased donor and organ perfusion fluid cultures are obtained in order to inform recipient antimicrobial management and therefore reduce the risk of donor-derived bacterial and fungal infections. However, important heterogeneity exists in laboratory practice across organ procurement organizations and clinical management of culture results across transplant centers. While not standardized, the clinical approach to donors with positive bacterial and/or fungal cultures should be informed by the risk of donor-derived infection (DDI) and the consequence of organ non-utilization and account for potential unintended effects of antimicrobial use in the recipient. In this review, we summarize the literature on bacterial and fungal DDIs, describe the significance of positive cultures by anatomic site, and summarize current guidance on the management of positive cultures from donors or preservation fluids.

The impact of preservation fluid culture on graft site arteritis: A systematic review and meta-analysis

BACKGROUND

The role of culturing the graft preservation fluid (PF) is controversial and its impact on graft arteritis development remains unclear.

METHODS

Systematic literature search retrieving observational studies comparing solid organ transplant (SOT) recipients with culture-positive PF versus culture-negative PF. The quality of included studies was independently assessed according to the ROBINS-I tool for observational studies. Meta-analysis was performed using Mantel-Haenszel random-effect models. Graft site arteritis within 180 days from transplant was selected as the primary outcome.

RESULTS

Twenty-one observational studies (N = 2208 positive PF vs. 4458 negative) were included. Among positive PF, 857 (38.8%) were classified as high-risk group pathogens and 1351 (61.2%) as low-risk pathogens. Low-risk and negative PF showed similar odds ratios. A significant higher risk of graft arteritis was found in SOT recipients with a PF yielding a high-risk pathogen (odds ratio [OR] 18.43, 95% confidence interval [CI] 7.83-43.40) compared to low-risk and negative PF, with low heterogeneity (I² = 2.24%). Similar results were found considering separately high-risk bacteria (OR 12.02, 95%CI 4.88-29.60) and fungi (OR 71.00, 95%CI 28.07-179.56), with no heterogeneity (I² = 0%), and in the subgroup analyses of the liver (OR 16.78, 95%CI 2.95-95.47) and kidney (OR 19.90, 95%CI 4.78-82.79) recipients. However, data about diagnostic features of graft arteritis were very limited, indeed for only 11 of the 93 events histological or microbiological results were reported.

CONCLUSIONS

Our results may support the performance of PF culturing and a preemptive diagnostic or therapeutic management upon isolation of high-risk pathogens. Further studies based on a reliable diagnosis of graft arteritis are needed.

Effects of preservative fluid associated possible donor-derived carbapenem-resistant Klebsiella Pneumoniae infection on kidney transplantation recipients

BACKGROUND

Infections remain a major cause of morbidity and mortality in kidney transplant (KT) recipients. This study aimed to investigate the preservation fluid (PF) samples from deceased donors and report the impacts of possible donor-derived carbapenem-resistant Klebsiella pneumoniae (pdd-CRKP) infections on KT recipients.

METHODS

A retrospective study was performed that included all recipients who received kidney transplantation from deceased donors in our hospital between December 2018 and December 2020. A total of 212 patients received kidney transplantation from deceased donors, a total of 206 PF samples were collected, and 20 recipients had a CRKP-positive culture. Both donors and recipients with CRKP-positive PF cultures were divided into two groups, and continuous variables between the two groups were compared using independent-sample t tests and Mann-Whitney tests. Categorical variables were compared using the chi-square test or Fisher's exact test. The significance level of p values was set at 0.05.

RESULTS

A total of 337 recipients underwent kidney transplantation, including 212 recipients of organs from deceased donors and 110 corresponding deceased donors. A total of 206 PF samples were collected, and 20 recipients had CRKP-positive PF cultures. The donors' length of ICU stay was a potential risk factor for CRKP positivity in the PF culture (P < 0.05). Fifteen recipients were infected with pdd-CRKP, and the incidence of pdd-CRKP infection was 7.3% (15/206). The use of antibiotics, including ceftazidime-avibactam (CAZ-AVI), was a potential protective factor against death and graft loss in recipients with a CRKP-positive PF culture (P < 0.05).

CONCLUSIONS

This study shows that the incidence of pdd-CRKP is high in our centre, recipients with pdd-CRKP infection can still achieve a good prognosis with the use of antimicrobial agents including CAZ-AVI.

Severe Sepsis Mimicking Primary Nonfunction Following Liver Transplantation: Normothermic Machine Perfusion Is a Potential Environment for Bacterial Overgrowth and Transmission From Donor to Recipient. A Case Report

Primary nonfunction (PNF) in the early postoperative period following liver transplantation is fatal if not managed appropriately with early retransplantation. Severe early allograft dysfunction can mimic PNF. The identification of treatable causative factors such as sepsis, hepatic artery, or portal vein thrombosis is essential to distinguish it from PNF, and their early management may avoid the need for retransplantation. In this article, we describe a case of sepsis-induced severe liver dysfunction from a contaminated graft perfused with normothermic machine perfusion (NMP), which presented in a manner similar to PNF. The implications of graft contamination are poorly described. To our knowledge, this is the first report of bacterial contamination of a graft that underwent NMP and subsequently caused severe sepsis in the recipient. The conditions created with NMP may be optimal for certain micro-organisms to thrive. The role of the liver in the immune system is complex as it provides an essential barrier to enterically derived portal venous pathogens and produces numerous acute phase proteins that augment the systemic immune response. Additionally, the liver is also known to restrain harmful and excessive systemic immune responses such as those that occur with the sepsis syndrome. The relationship between bacterial graft contamination, sepsis, and graft dysfunction may be multidirectional.

Antibiotic therapy in case of positive cultures of kidney transplant preservation fluid: a nationwide survey of prescribing practices

Our survey aimed to describe current prescribing practices for perioperative antibiotic prophylaxis in French kidney transplant centers. We conducted a nationwide cross-sectional clinical vignette-based survey that we sent via email to hospital practitioners involved in perioperative management of kidney transplant patients (KTR). Nearly half of practitioners contacted (182/427, 42.6%) were respondents. A total of 167 getting enough kidney transplant activity were eligible for the survey. The response rate was 50.7% (68/134) among interns and 33.8% (99/293) among seniors. Positive perfusion fluids (PF) cultures for methicillin-susceptible Staphylococcus aureus were associated with antibiotic prescribing in 35% of cases, with no difference in prescribing in patients with diabetes, obesity, or delayed graft function. Antibiotic prescribing was most frequent with Pseudomonas aeruginosa (67%) and Klebsiella pneumoniae strains producing extended spectrum β-lactamases (57%). About 77%, 16%, and 13% of respondents, respectively, reported the existence of local practice guidelines for surgical antibiotic prophylaxis, a standardized approach for antibiotic prescribing in case of positive kidney transplant PF cultures, and local practice guidelines for systematical antibiotic prophylaxis in the early post-transplant period. In France, antibiotic prophylaxis practices in the perioperative kidney transplant period are very heterogeneous. To prevent unnecessary prescribing and bacterial resistance, evidence-based practice guidelines should be developed.

Microbiological epidemiology of preservation fluids in transplanted kidney: a nationwide retrospective observational study

OBJECTIVES

Kidney transplant recipients are at high-risk for donor-derived infections in the early post-transplant period. Transplant preservation fluid (PF) samples are collected for microbiological analysis. In case of positive PF cultures, the risk for the recipient is unknown and there is no consensus for prescribing prophylactic antibiotics. This nationwide observational study aimed to determine the epidemiology of bacterial and fungal agents in kidney transplant PF cultures and identify risk factors associated with positive PF cultures.

METHODS

We performed a retrospective observational study on the following data collected from a national database between October 2015 and December 2016: characteristics of donor, recipient, transplantation, infection in donor and PF microbiological data.

RESULTS

Of 4487 kidney transplant procedures, including 725 (16.2%, 725/4487) from living donors, 20.5% had positive PF cultures (living donors: 1.8%, 13/725; deceased donors: 24.1%, 907/3762). Polymicrobial contamination was found in 59.9% (485/810) of positive PF cultures. Coagulase-negative staphylococci (65.8%, 533/810) and Enterobacteriaceae (28.0%, 227/810) were the most common microorganisms. Factors associated with an increased risk of positive PF cultures in multivariable analysis were (for deceased-donor kidney transplants): intestinal perforation during procurement (OR 4.4, 95% CI 2.1-9.1), multiorgan procurement (OR 1.4, 95% CI 1.1-1.7) and en bloc transplantation (OR 2.5, 95% CI 1.3-4.9). Use of perfusion pump and donor antibiotic therapy were associated with a lower risk of positive PF cultures (OR 0.4, 95% CI 0.3-0.5 and OR 0.6, 95% CI 0.5-0.7, respectively).

CONCLUSION

In conclusion, 24% of deceased-donor PF cultures were positive, and PF contamination during procurement seemed to be the major cause.

The Impact of Culturing the Organ Preservation Fluid on Solid Organ Transplantation: A Prospective Multicenter Cohort Study

Background

We analyzed the prevalence, etiology, and risk factors of culture-positive preservation fluid and their impact on the management of solid organ transplant recipients.

Methods

From July 2015 to March 2017, 622 episodes of adult solid organ transplants at 7 university hospitals in Spain were prospectively included in the study.

Results

The prevalence of culture-positive preservation fluid was 62.5% (389/622). Nevertheless, in only 25.2% (98/389) of the cases were the isolates considered "high risk" for pathogenicity. After applying a multivariate regression analysis, advanced donor age was the main associated factor for having culture-positive preservation fluid for high-risk microorganisms. Preemptive antibiotic therapy was given to 19.8% (77/389) of the cases. The incidence rate of preservation fluid-related infection was 1.3% (5 recipients); none of these patients had received preemptive therapy. Solid organ transplant (SOT) recipients with high-risk culture-positive preservation fluid receiving preemptive antibiotic therapy presented both a lower cumulative incidence of infection and a lower rate of acute rejection and graft loss compared with those who did not have high-risk culture-positive preservation fluid. After adjusting for age, sex, type of transplant, and prior graft rejection, preemptive antibiotic therapy remained a significant protective factor for 90-day infection.

Conclusions

The routine culture of preservation fluid may be considered a tool that provides information about the contamination of the transplanted organ. Preemptive therapy for SOT recipients with high-risk culture-positive preservation fluid may be useful to avoid preservation fluid-related infections and improve the outcomes of infection, graft loss, and graft rejection in transplant patients.

Donor Leucocytosis Predicts Bacterial and Fungal Contamination of the Preservation Solution in Visceral Organ Transplantation

INTRODUCTION

Contamination of the preservation solution may contribute to septic complications that can occur after transplantation and cause higher morbidity and mortality among recipients. The aim of this study was to determine potential donor-related predictors of positive microbiological findings in the preservation solution.

DESIGN

We retrospectively studied 16 donor parameters on data from our center for microbiological findings in the preservation solution used in solid-organ recovery. From January 2008 through December 2011, 976 solid organs were transplanted, and in 167, the solution was positive for contaminants.

RESULTS

The most frequently detected contaminant was coagulase-negative staphylococci. Only the donor leucocyte count (cutoff at 9.1 × 10⁹/L) predicted positive microbiological findings in the preservation solution ( P = .0024). Multivariable regression analysis found that donor age, donor sex, intensive care unit stay, total number of organs recovered, and leucocyte count differentiated various categories of potentially pathogenic bacteria.

CONCLUSION

Donor leucocyte count higher than 9.1 × 10⁹/L predicts contamination of preservation solution.

Clinical impact of culture-positive preservation fluid on solid organ transplantation: A systematic review and meta-analysis

Contamination of the preservation fluid (PF) used for donated organs is a potential source of post-transplant infection. However, the information on this issue is scarce. We therefore conducted a systematic review and meta-analysis to assess the incidence of culture-positive PF and its impact on solid organ transplant (SOT) recipients. Seventeen studies were identified and included. The overall incidence of culture-positive PF was 37% (95% CI: 27% to 49%), and the incidence of PF-related infections among SOT recipients with PF cultures that grew pathogenic microorganisms was 10% (95% CI: 7% to 15%). There were differences in the rates of infections due to pathogenic microorganisms between SOT recipients who received pre-emptive treatment and those who did not, but without statistical significance. The mortality rate among SOT recipients with PF-related infection was 35% (95% CI: 21% to 53%). In conclusion, although contamination of the PF of donated organs is frequent, the incidence of PF-related infection is relatively low. A closely clinical and microbiologic monitoring of the SOT recipient in case of culture-positive PF, regardless of the type of microorganism isolated might be do in order to establish a prompt diagnosis of PF-related infection.

The Etiology, Incidence, and Impact of Preservation Fluid Contamination during Liver Transplantation

The role of contaminated preservation fluid in the development of infection after liver transplantation has not been fully elucidated. To assess the incidence and etiology of contaminated preservation fluid and determine its impact on the subsequent development of infection after liver transplantation, we prospectively studied 50 consecutive liver transplants, and cultured the following samples in each instance: preservation fluid (immediately before and at the end of the back-table procedure, and just before implantation), blood, and bile from the donor, and ascitic fluid from the recipient. When any culture was positive, blood cultures were obtained and targeted antimicrobial therapy was started. We found that the incidence of contaminated preservation fluid was 92% (46 of 50 cases of liver transplantation per year), but only 28% (14/50) were contaminated by recognized pathogens. Blood and bile cultures from the donor were positive in 28% and 6% respectively, whereas ascitic fluid was positive in 22%. The most frequently isolated microorganisms were coagulase-negative staphylococci. In nine cases, the microorganisms isolated from the preservation fluid concurred with those grown from the donor blood cultures, and in one case, the isolate matched with the one obtained from bile culture. No liver transplant recipient developed an infection due to the transmission of an organism isolated from the preservation fluid. Our findings indicate that contamination of the preservation fluid is frequent in liver transplantation, and it is mainly caused by saprophytic skin flora. Transmission of infection is low, particularly among those recipients given targeted antimicrobial treatment for organisms isolated in the preservation fluid.

Clinical Significance of Contamination of the Preservation Solution in Liver Transplantation

INTRODUCTION

The aim of the present study was to describe the incidence and microbiological profiles of positive cultures obtained from preservation solution (PS) and correlate these findings with infectious complications detected in the liver transplant (LT) recipient.

PATIENTS

We conducted a single-center, retrospective study between December 2010 and August 2014 among 178 LT. In all grafts, a PS culture was carried out. All the infections in the receipt until hospital discharge were collected. In patients with >1, infection was considered the most severe according to Clavien-Dindo classification.

RESULTS

PS culture was positive for bacterial or fungal agents in 79 of 178 LT recipients (44%). The most commonly cultured organisms were coagulase-negative staphylococci (64%), Enterobacteriaceae (17%), and Staphylococcus aureus (4.7%). In the 79 patients with positive PS, 49 blood cultures were requested in the period after LT. Twenty-five postoperative infections (31.7%) were diagnosed. Only 4 of 79 patients (5%) with PS contamination had a postoperative infections related with isolated microorganism.

CONCLUSIONS

Contamination of PS appears in a high percentage of liver grafts before LT, although there is a poor correlation with postoperative infections in LT recipient. In these patients, a standardized process including fungal and bacterial cultures could be useful.

Fungal complications after Candida preservation fluid contamination in liver transplant recipients

Donor-derived fungal infections can be associated with severe complications in transplant recipients. Donor-derived candidiasis has been described in kidney transplant recipients where contamination of the preservation fluid (PF) was a commonly proposed source. In liver transplantation, these fungal infections have been less explored. The aim of this study was therefore to determine the incidence and clinical relevance of Candida contamination of preservation fluid in the context of liver transplantation. A 5-year (2008-2012) retrospective multicentre study involving six French liver transplantation centers was performed to determine the incidence of Candida PF contamination. Postoperative clinical features, outcomes in recipients, and risk factors for Candida-related complications of liver transplantation were studied. Candida sp. was isolated from 28 of 2107 preservation fluid samples (1.33%). Candida albicans was the most common yeast (n = 18, 64%). Twenty-two recipients (78.5%) received antifungal therapy (echinocandins in 68%) for 7-37 days. Eight patients developed yeast-related complications (28.6%) including hepatic artery aneurysms (n = 6) and Candida peritonitis (n = 2). The 1-year mortality rate among patients after a yeast-related complication was 62.5%. The incidence of Candida PF contamination was low, but was associated with dramatic postoperative complications and high mortality. Close radiological follow-up may enable early recognition of the arterial complications associated with PF contamination by Candida.

High-resolution CT findings of pulmonary infections after orthotopic liver transplantation in 453 patients

OBJECTIVES

The objective of this study was to review the high-resolution CT (HRCT) findings in patients with pulmonary infection after orthotopic liver transplantation (OLT) and to determine distinguishing findings among the various types of infection.

METHODS

This study included 453 consecutive liver transplant recipients with pulmonary infection, on whom HRCT of the chest was performed within 24 h of the beginning of symptoms and for whom proven diagnosis had taken place within 1 week of the onset of symptoms. Two radiologists analysed the CT images; final decisions regarding the findings were reached by consensus.

RESULTS

Bacterial and viral pneumonia made up the bulk of infections (63.4% and 29.4%, respectively), followed by fungal infiltrates (24.5%). Large nodules were most common in patients with fungal pneumonia, having been seen in 38 (54%) of the 70 patients with fungal pneumonia, 22 (10%) of 220 with bacterial pneumonia (p=0.0059) and 6 (8%) of 78 with viral pneumonia (p=0.0011). The halo sign was also more frequent in patients with fungal pneumonia, having been seen in 38 (54%) of the 70 patients with fungal pneumonia, 17 (8%) of 220 with bacterial pneumonia (p=0.0026) and 7 (9%) of 78 with viral pneumonia (p=0.0015). There was no statistically significant difference in the prevalence of the other HRCT patterns including air-space consolidation, ground-glass attenuation and small nodules among bacterial, viral and fungal infections (all p>0.05).

CONCLUSION

The presence of large nodules with the halo sign is most suggestive of fungal infection after OLT. Other HRCT patterns are not helpful in distinguishing among the various types of infection seen in liver transplant recipients.

Donor-derived fungal infections in organ transplant recipients: guidelines of the American Society of Transplantation, infectious diseases community of practice

Donor-derived fungal infections can be associated with serious complications in transplant recipients. Most cases of donor-derived candidiasis have occurred in kidney transplant recipients in whom contaminated preservation fluid is a commonly proposed source. Donors with cryptococcal disease, including those with unrecognized cryptococcal meningoencephalitis may transmit the infection with the allograft. Active histoplasmosis or undiagnosed and presumably asymptomatic infection in the donor that had not resolved by the time of death can result in donor-derived histoplasmosis in the recipient. Potential donors from an endemic area with either active or occult infection can also transmit coccidioidomycosis. Rare instances of aspergillosis and other mycoses, including agents of mucormycosis may also be transmitted from infected donors. Appropriate diagnostic evaluation and prompt initiation of appropriate antifungal therapy are warranted if donor-derived fungal infections are a consideration. This document discusses the characteristics, evaluation and approach to the management of donor-derived fungal infections in organ transplant recipients.