Incidence and clinical relevance of bacterial contamination in preservation solution for liver transplantation

Effect of preservation fluid contamination and associated possible donor-derived infections on early postoperative prognosis in kidney transplant recipients

BACKGROUND

The study aims to analyze the epidemiology of preservation fluid (PF) contamination and investigate the impact of PF contamination and possible donor-derived infections(p-DDI) on early postoperative prognosis in kidney transplant (KT) recipients.

METHODS

A total of 256 PF samples were collected for microbiological evaluation from all KT recipients who received deceased donor donations in our hospital from June 2018 to August 2022. Data on the baseline and clinical characteristics of these PF corresponding to recipients and donors were extracted from the electronic medical record. It mainly included the early postoperative complications and prognosis of KT recipients.

RESULTS

From June 2018 to August 2022, 597 kidney transplants were performed in our center, with 260 recipients receiving kidney transplantation from donation after citizens' death. A total of 256 samples of PF were collected, of which 64.5% (165/256) were culture positive, and 24.6% (63/165) of the culture-positive PF were polymicrobial contamination. A total of 238 strains were isolated, of which coagulase-negative staphylococci (CoNS) had the highest proportion of 34.0% (81/238), followed by Klebsiella pneumoniae with 20.6% (49/238) and Escherichia coli with 8.8% (21/238). Recipients with culture-positive PF had a significantly higher incidence of postoperative infection (55.8% vs. 20.9%, P < 0.001) and DGF (38.2% vs. 24.2%, P = 0.023). In addition, the incidence of p-DDI was 12.9% (33/256). CRKP was the most common pathogen causing p-DDI. The recipients who developed p-DDI had a higher rate of graft loss (9.1% vs. 0.4%, P < 0.001), mortality (12.1% vs. 3.1%, P = 0.018), and longer postoperative hospital stay (30 days (19.5-73.5) vs. (22 days (18-32), P < 0.05) compared with recipients who did not develop p-DDI.

CONCLUSIONS

Culture-positive PF is potentially significant for KT recipients, and p-DDI may increase the risk of poor prognosis for recipients. Prophylactic anti-infective treatment should be actively performed for highly virulent or multidrug-resistant (MDR) pathogens (especially Carbapenem-resistant Klebsiella pneumoniae, CRKP) in PF to avoid the occurrence of p-DDI.

Substantial decline of organ preservation fluid contamination following adoption of ischemia-free liver transplantation: a post-hoc analysis

INTRODUCTION

Preservation fluid (PF) contaminations are common in conventional liver transplantation (CLT) and presumably originate from organ or PF exposures to the external environment in a non-strict sterile manner. Such exposures and PF contamination may be avoided in ischaemia-free liver transplantation (IFLT) because of the strict sterile surgical procedures. In this study, the authors evaluated the impact of IFLT on organ PF contamination.

METHODS

A post-hoc analysis using data from the first randomized controlled trial of IFLT was performed to compare the incidence, pathogenic spectrum of PF contamination, and incidence of early recipient infection between IFLT and CLT. Multivariable logistic regression was used to explore risk factors for PF contamination.

RESULTS

Of the 68 cases recruited in the trial, 64 were included in this post-hoc analysis. The incidence of culture-positive PF was 9.4% (3/32) in the IFLT group versus 78.1% (25/32) in the CLT group ( P <0.001). Three microorganisms were isolated from PF in the IFLT group, while 43 were isolated in the CLT group. The recipient infection rate within postoperative day 14 was 3.1% (1/32) in the IFLT group vs 15.6% (5/32) in the CLT group, although this difference did not reach statistical significance ( P =0.196). Multivariate analysis revealed that adopting IFLT is an independent protective factor for culture-positive PF.

CONCLUSION

PF contamination is substantially decreased in IFLT, and IFLT application is an independent protective factor for PF contamination. Using rigorous sterile measures and effective antibiotic therapy during IFLT may decrease PF contamination.

Perfusion fluid-related infections in liver transplant recipients: A 5-year, single-center, retrospective study

BACKGROUND

Perfusion fluid (PRF) is employed in liver transplantation (LTx) to maintain graft viability. Still, it represents a new potential way of infection transmission in LTx recipients (LTRs). Currently, no systematic research has investigated this topic.

METHODS

Five-year single-center retrospective study conducted on LTRs from January 2017 to December 2021. We analyzed the incidence of positive PRF culture (PRF+) and perfusion fluid-related infections (PRF-RI) and their associated factors. We also assessed 1-year mortality, both overall and infection-related.

RESULTS

Overall, 234 LTx were included. PRF+ were found in 31/234 (13.2%) LTx for a total of 37 isolates, with >1 isolate identified in 5 (2.1%) cases. High-risk microorganisms (Enterobacterales 13/37, Enterococcus spp. 4/37, S. aureus 3/37, P. aeruginosa 2/37) were isolated in 25/37 (67.6%) LTRs, the remaining being coagulase-negative staphylococci (12/37, 32.4%). Antimicrobial prophylaxis was administered to all LTRs, always active against the isolate even if suboptimal in 19 cases (61.3%). PRF-RI developed in 4/234 LTx (1.7%), and prophylaxis was considered suboptimal in 2/4 of them. The isolation of >1 microorganism in PRF culture was associated with an increased risk of developing PRF-RI (OR 37.5 [95%CI 2.6-548.4], p = .01). PRF-RI were associated with longer ICU stays (p = .005) and higher 1-year mortality, both overall and related to infections (p = .001).

CONCLUSION

Despite PRF+ being infrequent, only a minority of patients develops PRF-RI. Nonetheless, once occurred, PRF-RI seems to increase morbidity and mortality rates.

Impact of Culture-Positive Preservation Fluid on Early Morbidity and Mortality After Lung Transplantation

The prevalence, risk factors and outcomes associated with culture-positive preservation fluid (PF) after lung transplantation (LT) are unknown. From January 2015 to December 2020, the microbiologic analyses of PF used to store the cold ischaemia-placed lung graft(s) of 271 lung transplant patients were retrospectively studied. Culture-positive PF was defined as the growth of any microorganism. Eighty-three (30.6%) patients were transplanted with lung grafts stored in a culture-positive PF. One-third of culture-positive PF were polymicrobial. Staphylococcus aureus and Escherichia coli were the most frequently isolated microorganisms. No risk factors for culture-positive PF based on donor characteristics were identified. Forty (40/83; 48.2%) patients had postoperative pneumonia on Day 0 and 2 (2/83; 2.4%) patients had pleural empyema with at least one identical bacteria isolated in culture-positive PF. The 30-day survival rate was lower for patients with culture-positive PF compared with patients with culture-negative PF (85.5% vs. 94.7%, p = 0.01). Culture-positive PF has a high prevalence and may decrease lung transplant recipient survival. Further studies are required to confirm these results and improve understanding of the pathogenesis of culture-positive PF and their 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.

Klebsiella pneumoniae infection in a liver transplant patient: A case report and review of the literature

The share of Klebsiella pneumoniae in infections has been recently increasing. Multidrug-resistant strains that produce more than one antibiotic resistance mechanism are also increasingly isolated. Contamination of the organs preservation fluid occurs quite often, but the isolated microorganisms are mainly saprophytic bacteria that are part of the skin microbiota (coagulase-negative Staphylococcus, Corynebacterium spp). The following case describes a K. pneumoniae blood infection in a patient after liver transplantation. Susceptibility of the strains to chosen antimicrobials was determined using the automated method. For strain isolated from blood, it was confirmed by loop-mediated isothermal amplification of genetic material.

Candida Contamination in Kidney and Liver Organ Preservation Solution: Does It Matter?

INTRODUCTION

Fungal infections remain a major challenge affecting outcomes after kidney (KT) and liver transplantation (LT).

METHODS

In this retrospective single center study, the incidence of Candida contamination in renal and hepatic graft preservation solution (PS) was evaluated. In addition, Candida associated infections in recipients and related complications were analyzed.

RESULTS

Overall, the PS of 1248 hepatic and 1273 renal grafts were evaluated. The incidence of fungal contamination in the PS of hepatic and renal grafts was 1.2% and 0.86%, respectively. Additionally, the hepatic PS of one patient who underwent a combined liver-kidney transplant had Candida contamination. Candida albicans was the most common organism (70.4%) and 65.4% of the patients received antifungal treatment. Candida-associated complications in the recipients was 19%. Complications in LT patients included Candida peritonitis and Candida sepsis. Two KT recipients with contaminated PS developed a mycotic aneurysm at the anastomotic site resulting in severe bleeding. The 1-year mortality in patients with PS contamination for LT and KT recipients was 33% and 18%, respectively. Although the incidence of fungal contamination of PS was low, contaminated PS was associated with a high mortality.

CONCLUSION

The results of the study suggest that PS should be evaluated for fungal growth.

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.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

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.

Donor-derived infections among Chinese donation after cardiac death liver recipients

AIM

To investigate blood cultures of deceased donors and report the confirmed transmission of bacterial infection from donors to liver recipients.

METHODS

We retrospectively studied the results of blood cultures among our donation after cardiac death (DCD) donors and calculated the donor-derived bacterial infection rates among liver recipients. Study participants underwent liver transplantation between January 1, 2010 and February 1, 2017. The study involved a total of 67 recipients of liver grafts from 67 DCD donors. We extracted the data of donors’ and patients’ characteristics, culture results and clinical outcomes, especially the post-transplant complications in liver recipients, from electronic medical records. We analyzed the characteristics of the donors and the corresponding liver recipients with emphasis put on donor-derived infections.

RESULTS

Head trauma was the most common origin of death among our 67 DCD donors (46.3%). Blood taken prior to the procurement operation was cultured for 53 of the donors, with 17 episodes of bloodstream infections developing from 13 donors. The predominant organism isolated from the blood of donors was Gram-positive bacteria (70.6%). Only three (4.5%) of 67 liver recipients developed confirmed donor-derived bacterial infections, with two isolates of multidrug-resistant Klebsiella pneumoniae and one isolate of multidrug-resistant Enterobacter aerogenes. The liver recipients with donor-derived infections showed relation to higher crude mortality and graft loss rates (33.3% each) within 3 mo post transplantation, as compared to those without donor-derived infections (9.4% and 4.7%, respectively). All three liver recipients received appropriate antimicrobial therapy.

CONCLUSION

Liver recipients have high occurrence of donor-derived infections. The liver recipients with donor-derived multidrug-resistant Enterobacteriaceae infections can have good outcome if appropriate antimicrobial therapy is given.

Continuous monitoring of the liver graft temperature: relationship between bacterial contamination of the perfusion fluid and early outcome

BACKGROUND

A potential mechanism of the infection would be an infected donor, contamination at the time of the infusion and/or packaging, back-table procedure, and finally during the transplantation, all are potential sources of infection. The aim of our study is to analyze the incidence and significance of infection in the preservation solution according with the graft temperature. The second aim was to analyze the impact graft temperature on the clinical infections and the ischemia reperfusion injury.

METHODS

Sixteen donors were prospectively included in this study, including 9 males and 7 females. The liver graft temperature monitoring shows variation in four different phases: at the harvesting beginning, before the graft packaging, at the beginning of the backtable, at the end of the backtable.

RESULTS

There was no correlation between the functionality of the graft and the temperature of the perfusion fluid.

CONCLUSIONS

In conclusion, we did not found a correlation between graft temperature, culture of the preservation solution and early post-transplant follow up.

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.

Use of the BacT/alert system for rapid detection of microbial contamination in a pilot study using pancreatic islet cell products

At the Islet Isolation Laboratory of the Scottish National Blood Transfusion Service, manual sterility testing data show that contamination rates are 57.7% for pancreas transport fluid, 4.3% for postpurification islet samples, and 0% for pretransplant islet samples. This pilot study presents the BacT/Alert System as an alternative to manual testing to provide more rapid and sensitive sterility results for islet cell products.

Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor.

Update on donor-derived infections in liver transplantation

Advances in surgical techniques, immunosuppressive medications, and robust infectious disease prophylaxis have resulted in liver transplantation becoming the treatment of choice for patients with end-stage liver disease and unresectable hepatocellular carcinoma. Nonetheless, organ transplantation is not without risk. Unexpected donor-derived disease transmission is a newly recognized risk that complicates approximately 0.2% of all organ transplants. We review the epidemiology of donor-derived infectious diseases and methods of risk mitigation with a focus on liver transplantation.

Microbiological findings of culture-positive preservation fluid in liver transplantation

Bacterial and fungal infections are the leading cause of mortality in liver transplant (LT) recipients. Few studies have examined the incidence of culture-positive preservation fluid (PF) and the outcome of related recipients. The aim of this study was to determine the incidence and the microbiologic findings of PF positive cultures, and to evaluate the impact on morbidity and mortality of LT recipients. A retrospective analysis of PF cultures performed after 477 LTs from cadaveric grafts between January 2001 and February 2008 was conducted. Forty-five (9.5%) PFs were found to be positive with 1 or 2 pathogens. The demographic profiles of recipients of PF with positive or negative cultures were similar. Enterobacteriaceae species were the most frequent organisms (n = 30), followed by Staphylococcus aureus (n = 5), coagulase-negative staphylococci (n = 5), enterococci (n = 4), and yeasts (n = 3). Mortality rate at 1 month was not significantly different in recipients with positive or sterile PF cultures (88.1% vs. 87.7%, respectively). The rate of bacteremia among LT recipients with positive or negative PF cultures was not statistically different. Systemic infections caused by the pathogen cultured from the PF occurred in 8 (18%) of the 45 recipients, including bacteremia (4/8) or intra-abdominal sepsis (5/8). Causative organisms were Enterobacteriaceae species (n = 5), Candida species (n = 2), and Enterococcus faecium (n = 1). Among the 8 patients who developed infection with the PF organism, 4 (50%) died in the intensive care unit (ICU) vs. an ICU mortality rate of 8% (3/37) in those who did not develop infection with the PF organism (P < 0.05). Infection occurred less frequently in recipients who received antimicrobial therapy with activity against the PF isolate than in those without appropriate treatment (41% vs. 3.8%, P < 0.005). Those who develop infection with organisms recovered from PF cultures appear to have high early mortality rates; therefore, appropriate antimicrobial therapy against organisms cultured from PF should be given.