Infections in liver transplantation: risk factors and strategies for prevention

Modulatory immune responses in fungal infection associated with organ transplant - advancements, management, and challenges

Organ transplantation stands as a pivotal achievement in modern medicine, offering hope to individuals with end-stage organ diseases. Advancements in immunology led to improved organ transplant survival through the development of immunosuppressants, but this heightened susceptibility to fungal infections with nonspecific symptoms in recipients. This review aims to establish an intricate balance between immune responses and fungal infections in organ transplant recipients. It explores the fundamental immune mechanisms, recent advances in immune response dynamics, and strategies for immune modulation, encompassing responses to fungal infections, immunomodulatory approaches, diagnostics, treatment challenges, and management. Early diagnosis of fungal infections in transplant patients is emphasized with the understanding that innate immune responses could potentially reduce immunosuppression and promise efficient and safe immuno-modulating treatments. Advances in fungal research and genetic influences on immune-fungal interactions are underscored, as well as the potential of single-cell technologies integrated with machine learning for biomarker discovery. This review provides a snapshot of the complex interplay between immune responses and fungal infections in organ transplantation and underscores key research directions.

Surgical Site Infections in Liver Transplant Patients: A Single-Center Experience

AIM

The aim of the study was a single-center assessment of occurrence of surgical site infections (SSI) in patients after liver transplantation and an attempt to determine factors that may contribute to this complication.

PATIENTS AND METHODS

Analysis of medical records of 60 adult patients, who underwent first transplantation in 2016 and 2017 was conducted. Selected pre-, intra-, and postoperative factors were assessed. Statistical analysis was performed with StatSoft Statistica 13.1 PL package.

RESULTS

SSI occurred in 25% of liver recipients, with average timing of diagnosis on the 14th day after surgery. Mean duration of hospitalization was significantly longer in patients who experienced SSI than in patients without this complication (35.8 ± 8.9 days vs 25.2 ± 6 days, P < .0001). SSI occurred a little more frequently in men and older recipients, as well as in overweight and underweight patients (not significant). An indication for transplantation did not have an impact on SSI occurrence. The complication was more likely in patients with diabetes and renal failure prior to transplantation (P > .05). Duration of the procedure, blood loss and prolonged drainage did not have any impact on SSIs. SSI was significantly more common in recipients with lower total protein value (P < .0002) and anemia (P < .0002) in early postoperative period.

CONCLUSION

Among the studied population, a high incidence of SSI was noted, and that some of the identified risk factors differ from those described in the literature.

Logistic Coordination in Pediatric Liver Transplantation: Criteria for Optimization

INTRODUCTION

Logistic organization of the transplantation coordination process aims to synchronize the recovery and recipient team and to reduce to a minimum the graft's cold ischemia time (CIT), which, in turn, is known, to have deleterious effects on the graft and recipient, if prolonged. To determine whether variables influencing the different steps in the coordination process might allow for reducing CIT, this study aimed to analyze these variables.

PATIENTS AND METHODS

Retrospective analysis of 61 pediatric liver transplantations from 2006 to 2015 in the Geneva University Hospitals.

RESULTS

Length of donor hepatectomy was increased for split grafts (P < .0001). Length of recipient hepatectomy was longer in the case of previous surgery (P = .06). The recipient team waiting time for the graft was longer for split grafts (P = .01). The graft waiting time at the recipient site was longer for whole grafts (P = .0005) and increased recipient weight (P = .03). The graft waiting time at the donor site was doubled in the case of recovery of organs after the liver by the same team (P = .007). The graft waiting time at the donor and recipient site not surprisingly increased the CIT (P = .007 and < .0001, respectively).

CONCLUSION

CIT depends on waiting times during the entire coordination process, which largely depends on the estimation of hepatectomy lengths. A more accurate estimation, considering graft type and recipient's previous surgery and weight, might allow for decreasing CIT and consequently improve outcomes after pediatric liver transplantation.

Hepatic abscess: Diagnosis and management

Microbial contamination of the liver parenchyma leading to hepatic abscess (HA) can occur via the bile ducts or vessels (arterial or portal) or directly, by contiguity. Infection is usually bacterial, sometimes parasitic, or very rarely fungal. In the Western world, bacterial (pyogenic) HA is most prevalent; the mortality is high approaching 15%, due mostly to patient debilitation and persistence of the underlying cause. In South-East Asia and Africa, amebic infection is the most frequent cause. The etiologies of HA are multiple including lithiasic biliary disease (cholecystitis, cholangitis), intra-abdominal collections (appendicitis, sigmoid diverticulitis, Crohn's disease), and bile duct ischemia secondary to pancreatoduodenectomy, liver transplantation, interventional techniques (radio-frequency ablation, intra-arterial chemo-embolization), and/or liver trauma. More rarely, HA occurs in the wake of septicemia either on healthy or preexisting liver diseases (biliary cysts, hydatid cyst, cystic or necrotic metastases). The incidence of HA secondary to Klebsiella pneumoniae is increasing and can give rise to other distant septic metastases. The diagnosis of HA depends mainly on imaging (sonography and/or CT scan), with confirmation by needle aspiration for bacteriology studies. The therapeutic strategy consists of bactericidal antibiotics, adapted to the germs, sometimes in combination with percutaneous or surgical drainage, and control of the primary source. The presence of bile in the aspirate or drainage fluid attests to communication with the biliary tree and calls for biliary MRI looking for obstruction. When faced with HA, the attending physician should seek advice from a multi-specialty team including an interventional radiologist, a hepatobiliary surgeon and an infectious disease specialist. This should help to determine the origin and mechanisms responsible for the abscess, and to then propose the best appropriate treatment. The presence of chronic enteric biliary contamination (i.e., sphincterotomy, bilio-enterostomy) should be determined before performing radio-frequency ablation and/or chemo-embolization; substantial stenosis of the celiac trunk should be detected before performing pancreatoduodenectomy to help avoid iatrogenic HA.

Quality of surgical care in liver and small-bowel transplant: approach to risk assessment and antibiotic prophylaxis

In August 2002, The Centers for Medicare and Medicaid Services and the Centers for Disease Control and Prevention implemented the National Surgical Infection Prevention project. The goal of the project was to decrease the morbidity and mortality associated with postoperative surgical site infections through appropriate selection and timing of administration and discontinuation of prophylactic antimicrobials. The National Surgical Infection Prevention project, however, excluded transplant surgeries from its focus because of the lack of randomized clinical trials comparing antimicrobial agents. The goals of this article are to (1) provide a framework for risk factors associated with surgical site infections in liver, small-bowel, and multivisceral transplants; (2) review general principles of the appropriate antimicrobial prophylaxis; (3) provide a framework for developing a triage of liver, small-bowel, and multivisceral transplant candidates for appropriate antibiotic prophylaxis; and (4) develop an approach to further quality improvements in transplant surgical care. A multidisciplinary team produced recommendations for antibacterial prophylaxis and monitoring.

Differential effects of plasma and red blood cell transfusions on acute lung injury and infection risk following liver transplantation

Patients with chronic liver disease have an increased risk of developing transfusion-related acute lung injury (TRALI) from plasma-containing blood products. Similarly, red blood cell transfusions have been associated with postoperative and nosocomial infections in surgical and critical care populations. Patients undergoing liver transplantation receive large amounts of cellular and plasma-containing blood components, but it is presently unclear which blood components are associated with these postoperative complications. A retrospective cohort study of 525 consecutive liver transplant patients revealed a perioperative TRALI rate of 1.3% (7/525, 95% confidence interval = 0.6%-2.7%), which was associated with increases in the hospital mortality rate [28.6% (2/7) versus 2.9% (15/518), P = 0.02] and the intensive care unit length of stay [2 (1-11 days) versus 0 days (0-2 days), P = 0.03]. Only high-plasma-containing blood products (plasma and platelets) were associated with the development of TRALI. Seventy-four of 525 patients (14.1%) developed a postoperative infection, and this was also associated with increased in-hospital mortality [10.8% (8/74) versus 2.0% (9/451), P < 0.01] and a prolonged length of stay. Multivariate logistic regression determined that the number of transfused red blood cell units (adjusted odds ratio = 1.08, 95% confidence interval = 1.02-1.14, P < 0.01), the presence of perioperative renal dysfunction, and reoperation were significantly associated with postoperative infection. In conclusion, patients undergoing liver transplantation have a high risk of developing postoperative complications from blood transfusion. Plasma-containing blood products were associated with the development of TRALI, whereas red blood cells were associated with the development of postoperative infections in a dose-dependent manner.

Quality of Surgical Care in Liver and Small-Bowel Transplant: Approach to Risk Assessment and Antibiotic Prophylaxis

In August 2002, The Centers for Medicare and Medicaid Services and the Centers for Disease Control and Prevention implemented the National Surgical Infection Prevention project. The goal of the project was to decrease the morbidity and mortality associated with postoperative surgical site infections through appropriate selection and timing of administration and discontinuation of prophylactic antimicrobials. The National Surgical Infection Prevention project, however, excluded transplant surgeries from its focus because of the lack of randomized clinical trials comparing antimicrobial agents. The goals of this article are to (1) provide a framework for risk factors associated with surgical site infections in liver, small-bowel, and multivisceral transplants; (2) review general principles of the appropriate antimicrobial prophylaxis; (3) provide a framework for developing a triage of liver, small-bowel, and multivisceral transplant candidates for appropriate antibiotic prophylaxis; and (4) develop an approach to further quality improvements in transplant surgical care. A multidisciplinary team produced recommendations for antibacterial prophylaxis and monitoring.

[Descriptive study of infectious complications in 109 consecutive liver transplant recipients]

INTRODUCTION

Infectious disease is a common, serious complication in liver transplant recipients. The etiology of these infections undergoes changes related with technical advances, prophylaxis, and local epidemiology.

METHODS

Prospective study in patients who underwent liver transplantation from July 2003 to December 2005 at the Hospital Universitario Virgen del Rocío. An observational description of infections occurring during the first 2 years following transplantation was carried out.

RESULTS

The incidence of infection was 1.32 episodes per patient over follow-up (443 +/- 248 days). The most frequent infections were surgical site (16%), cytomegalovirus (CMV) (14%), and urinary tract (11%). Etiologies included bacterial (64%), viral (31%), and fungal (5%) causes. The most common pathogens were CMV (21%), Escherichia coli (20%), among which, 40% were extended-spectrum beta-lactamase ESBL-producers, and Enterococcus spp. (11%). More than half the infectious episodes (58%) occurred in the first 4 months after transplantation. The 30-day mortality rate was 18%. In the group with infection, patient and graft survivals were 75% and 73% at the end of follow-up, and in the group without infection, survival was 80% in both cases (P=NS).

CONCLUSIONS

The most common infectious syndromes following liver transplantation were surgical site infection, CMV infection, and urinary tract infection. Bacteria were the most commonly isolated microorganisms, and there was a high rate of ESBL-producing E. coli.

Incremental costs of post-liver transplantation complications

BACKGROUND

Complications after liver transplantation are common and expensive. The incremental costs of adult posttransplantation liver transplantation complications and who pays for these complications (center or payor) is unknown.

STUDY DESIGN

We reviewed the medical and financial records (first 90 postoperative days) of all adult liver transplant recipients at our center between July 1, 2002, and October 30, 2005 (N = 214). The association of donor, recipient, and financial data points (total costs, reimbursements, and profits) was assessed using standard univariable analyses. The incremental costs of complications were determined with multiple linear regression models to control for the costs inherent to donor and recipient characteristics.

RESULTS

Univariate analyses demonstrated that both total hospital costs and reimbursements were substantially increased in patients with several different complications. Multiple linear regression analysis, controlling for recipient (age, gender, race, and laboratory Model for End-Stage Liver Disease [MELD]) and donor factors (donor risk index), noted that increased hospital costs and hospital reimbursements were independently associated with laboratory MELD (incremental costs of $3,368 and $2,787, respectively, per MELD point) and pneumonia ($83,718 and $68,214, respectively). A negative profit margin for the medical center was independently associated with peritonitis ($21,760). Commercial insurance was associated with no changes in total costs when compared with public insurer, but it was associated with decreased reimbursement and profit.

CONCLUSIONS

The incremental costs of complications in liver transplantation are high for both the medical center and payor, but medical center profits are not affected substantially. The payor bears the financial burden for post-liver transplantation complications.

Risk Factors for Pulmonary Aspergillus terreus Infection in Patients With Positive Culture for Filamentous Fungi

BACKGROUND

Invasive aspergillosis (IA) is a common fungal infection in immunocompromised patients and has a high mortality rate. Among patients with IA, Aspergillus terreus infections have become a growing concern in the past few years.

OBJECTIVE

To determine the clinical risk factors for isolation of and respiratory infection by A terreus in patients with culture findings positive for filamentous fungi.

METHODS

Cohort study of 505 consecutive isolates of filamentous fungi in 332 patients from one center. A terreus was present in 46 isolates from 40 patients (9.1%). Clinical histories were reviewed to identify the risk factors related to isolation of and infection by A terreus, which were grouped into three categories (ie, host factors, factors related to immunosuppression, and factors related to hospitalization), and were analyzed using a multiple logistic regression model.

RESULTS

A total of 192 of 505 isolates studied (38%) were due to invasive respiratory infection. A total of 27 of 46 cultures (58.7%) that were positive for A terreus were due to invasive infection (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.37 to 4.69; p = 0.034). The factors associated with invasive A terreus infection were prophylactic use of amphotericin B aerosols (OR, 27.8; 95% CI, 6.7 to 109.7; p = 0.001) and mechanical ventilation (OR, 3.3; 95% CI, 1.02 to 10.9; p = 0.04). Transplantation was associated with a lower risk of A terreus infection (OR, 0.2; 95% CI, 0.046 to 0.789; p = 0.02).

CONCLUSIONS

In patients with culture findings positive for filamentous fungi, the prophylactic use of amphotericin B aerosols and mechanical ventilation are associated with a higher risk of A terreus infections. In these patients, transplantation is associated with a lower risk of isolation and respiratory infection by A terreus.

Liver and kidney transplantation for polycystic liver and kidney-renal function and outcome

BACKGROUND

Polycystic liver disease (PLD) is a rare disorder frequently associated with polycystic kidney disease (PKD). Transplantation is a treatment option for these patients. Because of preservation of hepatic function in these patients, liver transplantation is not routinely utilized. We report a large series of PLD patients and their outcomes following liver and kidney transplantation.

METHODS

Fourteen patients underwent orthotopic liver transplantation (OLTx) for PLD between 1987 and 2003. Twelve patients had PKD combined with PLD. Nine patients received only liver transplantation. Five patients had combined liver and kidney transplantation. Thirteen patients (93%) survived for at least one year following liver transplantation. Two out of eight patients who received solitary liver transplantation later required kidney transplantation.

RESULTS

Pretransplant glomerular filtration rate (GFR) in patients with PKD was 75.8+/-25.4 ml/min/1.73 m. One year later, GFR was 37.2+/-8.3 ml/min/1.73 m. Kaplan-Meier analysis showed that one- and two-year graft survival for combined liver and kidney transplantation was 80% (n=5), whereas graft survival for solitary liver transplantation was 100% (n=9). Mean survival of patients who had combined liver and kidney transplantation was 46.7+/-54.2 months (n=5), whereas the mean survival for solitary liver transplant patients was 80.4+/-68.6 months (n=9) (P=0.36).

CONCLUSION

Transplantation is an excellent option for PLD with dramatic improvement in quality of life and acceptable morbidity. For combined liver and kidney transplantation one- and two-year patient survival rates were similar to combined transplantation for other indications. For patients with acceptable renal function at time of transplantation, solitary liver transplantation has an excellent outcome.

Biliary epithelial cell antibodies induce expression of toll-like receptors 2 and 3: a mechanism for post-liver transplantation cholangitis?

Studies to determine the role of preformed antibodies to biliary epithelial cells (BECs) in liver transplant rejections have been initiated. However, the clinical importance of these antibodies in the posttransplantation period still remains to be elucidated. Reactivity to BECs isolated from a normal healthy liver was investigated in sera of 56 patients before and after liver transplantation (LTX) using flow cytometry. Functional capacity of BEC antibodies was determined by the ability to induce expression of Toll-like receptors (TLRs) on BECs. Cytokine and chemokine production induced by BEC antibodies was determined by enzyme-linked immunosorbent assay. In all, 7 patients (13%) had BEC antibodies only pre-LTX, 14 (25%) only after LTX, 18 (32%) both before and after LTX, and 17 (30%) had no detectable antibodies. Presence of preformed BEC antibodies correlated with acute rejections (P < 0.03). Deposition of immunoglobulins in bile ducts was detected in biopsies of patients during rejections. Significantly higher numbers of patients with post-LTX antibodies (9 of 32) developed cholangitis, compared with 0 of 17 without antibodies (P < 0.02). Specificity studies indicated that these antibodies were both non-HLA- and HLA-specific. Normal BECs expressed mRNA but not the proteins for the TLRs. However, treatment with F(ab')2 fragments of BEC antibodies induced protein expression of TLRs 2 and 3 and significantly high production of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, epithelial neutrophil activating peptide (ENA)-78, and IL-8. In conclusion, BEC antibodies via induction of TLR2 and TLR3 expression, as well as inflammatory cytokine and chemokine production may induce epithelial cell inflammatory responses to bacterial components and contribute to posttransplantation cholangitis.

[Risk factors associated with invasive fungal infection in orthotopic liver transplantation]

BACKGROUND AND OBJECTIVE

Invasive fungal infection (IFI) in orthotopic liver transplantation (OLT) influences survival, hence the need for risk predictors. We have determined the incidence and risk factors associated with invasive fungal infection in OLT.

PATIENTS AND METHOD

165 OLTs performed in 152 receptors from May 1994 to May 1998 at the Hospital Juan Canalejo (La Coruña), were included in the study. Pre-surgical, surgical and post-surgical variables were evaluated. Those variables that independently influenced the development of IFI were determined by multivariate logistic regression.

RESULTS

IFI presented in 7 cases /152 patients (4.6%). In the univariate analysis, IFI was associated with pre-transplantation serum albumin, the number of blood units transfused, mechanical ventilation (OR = 7.56), re-transplantation (OR = 11.10) cytomegalovirus infection (OR = 8.35) and pre-transplantation GOT. In the multivariate analysis, the independent variables predicting IFI were the number of blood units transfused (OR = 1.21; 95% CI, 1.05-1.38), serum albumin pre-transplantation (OR = 0.06; 95% CI, 0.007-0.537) and re-transplantation (HR = 432; 95% CI, 9.80-19 058).

CONCLUSIONS

Pre-transplantation serum albumin, a clear predictor, the number of blood units transfused and re-transplantation are all independent predictors of IFI.

Recurrent cytomegalovirus disease, visceral leishmaniosis, and Legionella pneumonia after liver transplantation: a case report

PURPOSE

Recurrent cytomegalovirus (CMV) disease is a frequent complication of liver transplantation. Visceral leishmaniosis in a transplant recipient is, on the other hand, extremely rare and only two cases of kala-azar have been described after liver transplantation. Immunosuppressed patients are known to be at risk of Legionella infection and the relationship between infection with this organism and hospital water supplies has been well described. These three diseases carry a high mortality rate. Our report examines the potential relationship between these complications.

CLINICAL FEATURES

We describe the case of a liver transplant recipient who presented the three complications successively and survived. After reviewing the literature, we explore hypotheses linking these infections and discuss treatment strategies.

CONCLUSIONS

In the patient described, infection with leishmania probably occurred months prior to the clinical presentation, a delay that matches the incubation period of kala-azar. The simultaneous onset of leishmaniosis and of a high CMV viremia may have been a coincidence. However, CMV infection has been shown to be an independent predictor of invasive fungal infection in liver transplant recipients. CMV does indeed have a suppressive effect on the humoral and cellular immune response in vitro as well as in vivo. The clinical manifestations of leishmaniosis may, therefore, have been precipitated in this patient by the additive immunosuppressive effect of antirejection drugs and CMV.

Bio-ecological control of perioperative and ITU morbidity

BACKGROUND

Perioperative and intensive therapy unit (ITU) morbidity and mortality has remained unchanged during the past several decades, and this at an unacceptably high level. It is most likely, in the EU countries annually, that more than 1 million people suffer severe sepsis and some 300,000 die. Pharmaceutical attempts at prevention and treatment have, despite extensive efforts, hitherto failed to improve outcome more significantly. Much supports the fact that sepsis and its severe consequences are results of a malfunctioning innate immune system, impaired by both lifestyle and disease. A series of mostly simple measures to prevent further deterioration of the immune system, and to boost it, is recommended. Among the measures recommended are some modifications of surgical and postoperative management: restricted use of antibiotics, attempts made to maintain salivation and GI secretions, omission of prophylactic gastric decompression, postoperative drainage and preoperative bowel preparation, restricted use of stored blood, avoidance of overload with nutrients, uninterrupted enteral nutrition but also tight blood glucose control, supply of antioxidants, administration of prebiotic fibre and probiotic lactic acid bacteria. Nutritional control of postoperative morbidity includes use of so-called synbiotics, e.g. a combination of bioactive lactic acid bacteria (LAB) and bioactive plant fibres.

RESULTS

Dramatic reduction in (in reality, almost abolishment of) septic morbidity is reported following supplementation of specific bioactive lactic bacteria in combination with prebiotic plant fibres, as tried in controlled studies in connection with extensive abdominal operations, liver transplantation and severe acute pancreatitis.

[Incidence, risk factors and influence on survival of infectious complications in liver transplantation]

INTRODUCTION

Orthotopic liver transplantation (OLT) is successful therapy for patients with end-stage liver disease. Infection is currently a life-threatening complication for these patients. The aims of this study are to determine the incidence of various infections in patients with OLT, to study overall survival rates and survival as related to individual infections, and to investigate the risk factors associated with first episodes of bacterial (BI), fungal (FI), invasive fungal (IFI) and cytomegalovirus (CMV) infections.

METHODS

The study includes 165 OLTs performed in 152 recipients from May 1994 to May 1998. A descriptive analysis estimating the 95% confidence interval was performed with 100 variables stratified according to preoperative, operative and postoperative conditions. Cox regression analysis was used to identify the variables associated with infection. Survival studies were carried out with the Kaplan-Meier method.

RESULTS

Among the total, 66% of patients developed infection: 41.8% viral, 33.9% BI, 20.6% FI and 4.2% IFI. One-year and 4-year survival rates after transplantation were 90% and 75%, respectively. All the infections decreased survival. Multivariate analyses identified the following risk factors for the specific infections: BI - dialysis, mechanical ventilation, and time of organ ischemia during harvesting; FI - number of hours of surgery and pretransplantation plasma albumin concentrations; IFI - number of blood units transfused, pretransplantation plasma albumin and retransplantation. Cytomegalovirus infection was associated with FI and IFI in the univariate analysis, but the multivariate analysis identified no variables that independently increased the risk of developing this infection.

Salvage therapy of open, infected surgical wounds: a retrospective review using Techni-Care

OBJECTIVE

To determine outcome of infected surgical wounds treated with 3% para-chloro-meta-xylenol + 3% phospholipid PTC [PCMX-PL] (Techni-Care).

DESIGN

Retrospective review of patient records.

SETTING

University hospital.

PATIENTS

Thirty consecutively treated patients (sixteen male, fourteen female) who had developed open infected wounds (twenty-one abdominal [seventy percent], nine extremity [thirty percent]). Mean patient age was 50.1 years. All wounds were treated with commonly practiced wound care techniques (e.g., debridement, frequent dressing changes using saline or topical antibiotics, and, in most cases, parenteral antibiotics) for an extended period of time prior to intervention (mean = 35 days).

INTERVENTIONS

PCMX-PL, a topical microbicide, was used as adjunctive therapy. Eight outcome parameters were analyzed: (1) patient morbidity and mortality; (2) wound healing; (3) number of debridements; (4) wound culture results; (5) leukocytosis (peripheral white blood cell count > 10,000 cells/microl); (6) number of febrile days (temperature > 101 degrees F); (7) length of hospital stay; and (8) number of days of intensive care.

RESULTS

No treatment failures or adverse reactions to PCMX-PL were seen. Twenty (sixty-seven percent) wounds were healed or had been successfully closed while ten (thirty-three percent) were granulating well at sixty-day follow-up. The number of debridements, positive wound cultures, white-blood-cells, and febrile days decreased after PCMX-PL treatment began.

CONCLUSIONS

Despite severe underlying diseases, all patients were discharged from the hospital with closed or healing wounds. We recommend treatment with PCMX-PL as an adjunctive therapy for infected wounds particularly when standard care measures have failed.

[Early infection in liver transplant recipients: incidence, severity, risk factors and antibiotic sensitivity of bacterial isolates]

OBJECTIVES

To conduct a descriptive study with an analysis of risk factors for early infection in liver transplant patients, and to determine the resistance of the bacteria involved.

PATIENTS AND METHODS

The study included 149 liver transplant recipients. All cases of infection occurring 0-90 days after transplantation were considered early infection. Pre-, intra- and postoperative variables were analyzed, and isolated microorganisms were studied. Selective bowel decontamination with quinolones, and perioperative and antifungal prophylaxis were carried out in all patients.

RESULTS

The incidence of infection was 73.1%: bacterial (49.7%), viral (35.5%), fungal (10.1%) and mixed (4.5%). In the first postoperative month the most frequent infections were bacterial and in the second and third months, viral (p = 0.001). Multivariate analysis of risk factors identified the following: days of parenteral nutrition, duration of surgery > 5 hours, rejection and CMV seronegative status. Among 1278 cultures, the following microorganisms were isolated: 77.9% gram-positive cocci (GP) and 19% aerobic gram-negative bacilli (GNB). Sensitivity of Staphylococcus to vancomycin was 99.6-100% and to teicoplanin 97.9-100%. VAN resistance was observed in 1.2% of E. faecalis and 4.5% of E. faecium. Among S. aureus strains, 68.7% were MRSA. The resistance rate of GNB to quinolones was 38.8%.

CONCLUSIONS

Incidence of infection was higher the first 30 days after transplantation, with bacterial infection predominating. Duration of surgery > 5 hours was the most important risk factor for acquiring bacterial infection. GP were the most frequently isolated bacteria. Empirical treatment of early bacterial infection should include vancomycin or teicoplanin. Selective bowel decontamination resulted in a low incidence of GNB infections, among which there was 38.8% resistance to quinolones.

Histological patterns of rejection using oral microemulsified cyclosporine and tacrolimus (FK506) as monotherapy induction after orthotopic liver transplantation

BACKGROUND/AIMS

We describe the histological patterns of rejection in liver transplant recipients using induction therapies with cyclosporine and tacrolimus monotherapy compared with standard triple therapy as historical control.

METHODS

Patients formed part of the initial cohort in an open-labelled, randomised pilot study and were selected consecutively if they had histological rejection and no other confounding diagnoses. There were 13 patients in the cyclosporine monotherapy group (CsA), 11 in the tacrolimus monotherapy group and 13 in the triple therapy group (CAP). The histology of liver biopsies was reassessed blindly and the severity of rejection was recorded.

RESULTS

The total Royal Free Hospital (RFH) rejection scores as well as other histological features (zone 3 haemorrhage, apoptosis in zones 1 and 3, steatosis, cholestasis, nuclear vacuolation, lymphoblasts and ballooning) were comparable in the three groups. There was no difference in individual components of the histological features comprising the diagnosis of rejection, except that the portal inflammation score was significantly lower in the tacrolimus group when compared with the CsA group (p=0.04). There was no significant difference in the number of patients with moderate/severe rejection between the three groups. Overall, there was no significant increase in histological severity of rejection in the monotherapy groups.

CONCLUSIONS

The results suggest that the monotherapy may be as effective as the triple therapy in the initial post-transplant phase and that no particular graft histological changes were associated with the type of treatment.

The effect of surgical site infections on outcomes and resource utilization after liver transplantation

BACKGROUND

Although postoperative infections have a significant impact on morbidity and mortality after orthotopic liver transplantation (OLT), less is known about their economic implications. In this study, we sought to identify risk factors and estimate the impact of surgical site infections on 1-year mortality, graft survival, and resource utilization after OLT.

METHODS

We studied 777 first, single-organ liver transplant recipients from the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database. Surgical site infections (n = 292, 37.8%) were defined as bacterial or fungal infections of the liver, intestine, biliary tract, surgical wound, or peritoneum within 1 year of transplantation. A subset of these (n = 159) occurred during the transplant hospitalization and were used to estimate excess charges associated with surgical site infections.

RESULTS

Leaks in the choledochojejunostomy (odds ratio [OR] = 7.1, P =.001) and choledochocholedochostomy (OR = 2.5, P =.002), extended operation duration in hours (OR = 1.2, P =.002), serum albumin levels in grams per liters (OR = 0.71, P =.009), ascites (OR = 1.43, P =.037), and administration of OKT3 within 7 days (OR = 1.49, P =.039) significantly increased risk of infection. Surgical site infections did not significantly increase 1-year mortality (88.5% vs 91.5%, P =.19) but significantly increased 1-year graft loss (79.8% vs 86.5%, P =.022). Patients with surgical site infections incurred approximately 24 extra hospital days and $159,967 in excess charges (P =.0001). Multivariate analysis reduced the estimate of excess charges to $131,276 (P =.0001).

CONCLUSIONS

Liver transplant recipients who develop surgical site infection have significantly higher resource utilization requirements than those who do not. These results imply substantial returns to preventative efforts directed at surgical site infections in patients undergoing OLT.

Staphylococcus aureus nasal carriage in 104 cirrhotic and control patients. A prospective study

BACKGROUND/AIMS

Bacterial infections, specially Staphylococcus aureus (S. aureus) septicemia, remain a leading cause of death following liver transplantation. It has been demonstrated that nasal carriage of S. aureus is associated with invasive infections in patients undergoing hemodialysis and could be decreased by use of antibiotic nasal ointment. However, in cirrhotic patients, the frequency of nasal carriage is unknown. The aims of this study were to determine the prevalence of S. aureus nasal carriage in cirrhotic patients and to assess nosocomial contamination.

METHODS

One hundred and four patients were included in a prospective study, 52 cirrhotic and 52 control (hospitalized patients without cirrhosis or disease which might increase the rate of nasal carriage of S. aureus). On admission and after a few days of hospitalization, nasal specimens from each anterior naris were obtained for culture. S. aureus was identified by the gram strain, positive catalase and coagulase reactions; antibiotic susceptibility was determined using a disk-diffusion test.

RESULTS

Both groups were similar with regard to age and sex. The prevalence of nasal colonization on hospital admission was 56% in cirrhotic patients and 13% in control patients (p = 0.001). After an average of 4 days, 42% of cirrhotics and 8% of control patients were colonized (p = 0.001), without any nosocomial contamination. Three strains out of 29 were oxacillin-resistant in cirrhotic patients, and none in controls (p>0.05). There was no statistical difference in carriage rate according to sex, age, cause of cirrhosis and Child-Pugh score. Previous hospitalization (OR, 6.3; 95% CI, 2.3 to 19.9; p = 0.0006) and cirrhosis (OR, 4.4; 95% CI, 1.5 to 13.4; p = 0.0048) were independent predictors of colonization.

CONCLUSION

Cirrhotic patients had a higher S. aureus nasal carriage rate than control subjects. Previous hospitalization and cirrhosis diagnosis were correlated to nasal colonization. Further studies are necessary to determine if nasal decontamination could reduce S. aureus infections after liver transplantation.

The epidemiology and prevention of invasive aspergillosis

Over the past two decades, the incidence of invasive aspergillosis (IA) has risen inexorably. This is almost certainly the consequence of the more widespread use of aggressive cancer chemotherapy regimens, the expansion of organ transplant programmes and the advent of the acquired immunodeficiency syndrome (AIDS) epidemic. Despite the development of new approaches to therapy, IA still remains a life-threatening infection in immunocompromised patients and is the most important cause of fungal death in cancer patients. It is clear that the prevention of severe fungal infection by the use of effective infection control measure should be the priority of the teams involved in managing at-risk patients. The evidence from clinical and molecular epidemiological studies is reviewed and current thinking on sources and routes of transmission of the organism are discussed. Our increasing understanding of these has led to the development of a variety of environmental and general strategies for the prevention of IA. It is anticipated that these, coupled with the use of prophylactic antifungal agents active against Aspergillus spp., will have a significant impact upon the morbidity and mortality associated with this infection.

Ten years of liver transplantation: an evolving understanding of late graft loss

BACKGROUND

We undertook this study to understand the causes of late graft loss and long-term outcome in orthotopic liver transplantation (OLT) recipients.

METHODS

Prospectively collected data of 1174 consecutive OLT in 1045 adult patients who received liver grafts between April 1985 and August 1995 were reviewed. The causes of graft loss, pretransplant patient characteristics, and posttransplant events were analyzed in patients who survived at least 1 year after OLT, in an attempt to establish a link between these factors and graft loss.

RESULTS

One hundred fifty-nine (17.9%) grafts were lost after the first year. Of these, 132 grafts were lost by death and 27 by retransplantation. Recipients who survived the first year (n=884) had 5- and 10-year survivals of 81.4% and 67.2%, respectively. Death with a functioning graft occurred in 97 (61%) patients. The main causes of late graft loss were recurrent disease (n=48), cardiovascular and cerebral vascular accidents (n=28), infections (n=24), and chronic rejection (n = 15). Pretransplant heart disease and diabetes were found to be significant risk factors for late graft loss due to cardiovascular diseases and cerebral vascular accidents.

CONCLUSIONS

Survival of OLT patients who live beyond the first posttransplant year is excellent. Some patient characteristics may be associated with late graft loss. Compared with previous reports, this study shows an increased incidence of late graft loss secondary to recurrent diseases, de novo malignancies, cardiovascular diseases, and cerebral vascular accidents. Chronic rejection seems to be a less frequent cause of late graft loss. The prevention of recurrent disease and better immunosuppression may further improve these results.