Risk factors for cytomegalovirus and severe bacterial infections following liver transplantation: a prospective multivariate time-dependent analysis

Cytomegalovirus periodontal presence is associated with subgingival Dialister pneumosintes and alveolar bone loss

Destructive periodontal disease is associated with human cytomegalovirus (HCMV), Epstein-Barr type 1 virus (EBV-1) and other members of the Herpesviridae family as well as with various gram-negative anaerobic bacteria, including the Dialister pneumosintes species. This study aimed to determine possible interrelationships between periodontal HCMV, EBV-1, herpes simplex virus and D. pneumosintes, and relate the microbiological findings to periodontitis clinical status. Sixteen subjects each contributed paper point samples from two progressing and two stable periodontitis lesions, as determined by ongoing loss of probing attachment. Polymerase chain reaction methodology was used to identify the study herpesviruses and D. pneumosintes. Chi-squared tests, Fisher exact tests and multivariate logistic regression were employed to identify statistical associations among herpesviruses, bacteria and clinical variables. HCMV, and no other virus or combination of viruses, was positively associated with the presence of D. pneumosintes, and the relationship was specific for individual periodontitis sites with no detectable subject effect. D. pneumosintes was in turn positively associated with periodontal pocket depth and disease-active periodontitis. When the average percentage of alveolar bone loss in all teeth was treated as a response, HCMV remained significant even after D. pneumosintes was included in the model, suggesting that both HCMV and D. pneumosintes affected bone loss or, alternatively, HCMV affected factors not studied that themselves can induce bone loss. We hypothesize that periodontal HCMV sets the stage for subgingival proliferation of D. pneumosintes and subsequent periodontal disease progression. Studies on herpesviral-bacterial interactions may hold great promise for delineating important etio-pathogenic aspects of destructive periodontal disease.

CMV hepatitis after liver transplantation: incidence, clinical course, and long-term follow-up

Cytomegalovirus (CMV) hepatitis is described as the most frequent manifestation of CMV tissue invasive disease after liver transplantation. Its correlation with HLA-matching, hepatic artery thrombosis, and chronic rejection is still controversial. Risk factors, incidence, clinical course, and complications of CMV hepatitis were retrospectively analyzed in a 12-year series of 1,146 consecutive liver transplantations in 1,054 patients. All patients received only low-dose acyclovir but no gancyclovir prophylaxis. CMV infection was diagnosed by viral culture, pp65 antigenemia, or by polymerase chain reaction (PCR). CMV hepatitis was proven by liver biopsy. Treatment of CMV disease consisted of intravenous ganciclovir for a minimum of 14 days. Long-term follow-up of patients included monthly routine laboratory values and routine liver biopsies 1, 3 and 5 years after transplantation. CMV hepatitis was a rare event after liver transplantation, with a total incidence of 2.1% (24 cases). It was significantly more frequent in CMV seronegative (5.2%) than in seropositive recipients (0.7%). The leading indication in patients with CMV hepatitis was HCV cirrhosis (n = 8). The maximum number of pp65 positive white blood cells was 82 +/- 23 per 10,000 cells. Most courses manifested as isolated hepatitis; only 2 patients had disseminated disease. Nine of 24 patients had received OKT3 monoclonal antibodies because of steroid-resistant rejection before CMV hepatitis. In seronegative patients with CMV hepatitis, 71% revealed 1 or 2 HLA DR matches, in contrast to 32% in patients without CMV hepatitis. One-, 3-, and 5-year graft survival was 78%, 65%, and 59% in patients with CMV hepatitis compared with 88%, 81%, and 79% in patients without. Chronic rejection was observed in one patient, but already before onset of CMV hepatitis. Beneath D+R-constellation and OKT3 treatment as risk factors, HLA DR-matched grafts and HCV seem to favor manifestation of CMV hepatitis after liver transplantation. Long-term complications of CMV hepatitis were not observed, and especially no correlation with chronic rejection was found.

[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.

Bayesian estimation, simulation and uncertainty analysis: the cost-effectiveness of ganciclovir prophylaxis in liver transplantation

This paper demonstrates the usefulness of combining simulation with Bayesian estimation methods in analysis of cost-effectiveness data collected alongside a clinical trial. Specifically, we use Markov Chain Monte Carlo (MCMC) to estimate a system of generalized linear models relating costs and outcomes to a disease process affected by treatment under alternative therapies. The MCMC draws are used as parameters in simulations which yield inference about the relative cost-effectiveness of the novel therapy under a variety of scenarios. Total parametric uncertainty is assessed directly by examining the joint distribution of simulated average incremental cost and effectiveness. The approach allows flexibility in assessing treatment in various counterfactual premises and quantifies the global effect of parametric uncertainty on a decision-maker's confidence in adopting one therapy over the other.

A randomized, prospective, double-blinded evaluation of selective bowel decontamination in liver transplantation

BACKGROUND

Bacterial infection is a frequent, morbid, and mortal complication of liver transplantation. Selective bowel decontamination (SBD) has been reported to reduce the rate of bacterial infection after liver transplantation in uncontrolled trials, but benefits of this intervention have been less clear in controlled studies.

METHODS

Eighty candidates for liver transplantation were randomly assigned in a double-blinded fashion to an SBD regimen consisting of gentamicin 80 mg+polymyxin E 100 mg+nystatin 2 million units (37 patients) or to nystatin alone (43 patients). Both treatments were administered orally in 10 ml (increasing to 20 ml, according to predefined criteria), four times daily, through day 21 after transplantation. Anal fecal swab cultures were performed on days 0, 4, 7, and 21. Rates of infection, death, and charges for medical care were assessed from day 0 through day 60.

RESULTS

More than 85% of patients in both treatment groups began study treatment more than 3 days before transplantation. Rates of infection (32.4 vs. 27.9%), death (5.4 vs. 4.7%), or charges for medical care (median $194,000 vs. $163,000) were not reduced in patients assigned to SBD. On days 0, 4, 7, and 21, growth of aerobic gram-negative flora in fecal cultures of patients assigned to SBD was significantly less than that of patients taking nystatin alone; growth of aerobic gram-positive flora, anaerobes, and yeast was not significantly different.

CONCLUSION

Routine use of SBD in patients undergoing liver transplantation is not associated with significant benefit.

Diagnostic issues in liver transplantation pathology

Liver biopsy is used to determine the pathogenesis of liver dysfunction after liver transplantation. One or more causative factors may be identified on biopsy. The pathologist must be familiar with the histopathology of acute rejection to differentiate it from other potential complications, including biliary obstruction, intercurrent cytomegalovirus hepatitis, or recurrent disease. Consensus documents from the Banff international panel provide useful guidelines for the appropriate grading of acute and chronic rejection.

Auxiliary partial orthotopic versus standard orthotopic whole liver transplantation for acute liver failure: a reappraisal from a single center by a case-control study

OBJECTIVE

To reappraise the results of auxiliary partial orthotopic liver transplantation (APOLT) compared with those of standard whole-liver transplantation (OLT) in terms of postoperative death and complications, including neurologic sequelae.

SUMMARY BACKGROUND DATA

Compared with OLT, APOLT preserves the possibility for the native liver to recover, and to stop immunosuppression.

METHODS

In a consecutive series of 49 patients transplanted for fulminant or subfulminant hepatitis, 37 received OLT and 12 received APOLT. APOLT was done when logistics allowed simultaneous performance of graft preparation and the native liver partial hepatectomy to revascularize the graft as soon as possible. Each patient undergoing APOLT (12 patients) was matched to two patients undergoing OLT (24 patients) according to age, grade of coma, etiology, and fulminant or subfulminant type of hepatitis. All grafts in the study population were retrieved from optimal donors.

RESULTS

Before surgery, both groups were comparable in all aspects. In-hospital death occurred in 4 of 12 patients undergoing APOLT compared with 6 of 24 patients undergoing OLT. Patients receiving APOLT had 1 +/- 1.3 technical complications compared with 0.3 +/- 0.5 for OLT patients. Bacteriemia was significantly more frequent after APOLT than after OLT. The need for retransplantation was significantly higher in the APOLT patients (3/12 vs. 0/24). Brain death from brain edema or neurologic sequelae was significantly more frequent after APOLT (4/12 vs. 2/24). One-year patient survival was comparable in both groups (66% vs. 66%), and there was a trend toward lower 1-year retransplantation-free survival rates in the APOLT group (39% vs. 66%). Only 2 of 12 (17%) patients had full success with APOLT (i.e., patient survival, liver regeneration, withdrawal of immunosuppression, and graft removal). One of these two patients had neurologic sequelae.

CONCLUSIONS

Using optimal grafts, APOLT and OLT have similar patient survival rates. However, the complication rate is higher with APOLT. On an intent-to-treat basis, the efficacy of the APOLT procedure is low. This analysis suggests that the indications for an APOLT procedure should be reconsidered in the light of the risks of technical complications and neurologic sequelae.

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.

Differences between the quantitative antigenemia assay and the cobas amplicor monitor quantitative PCR assay for detecting CMV viraemia in bone marrow and solid organ transplant patients

The relationship between quantitative PCR (COBAS Amplicor CMV Monitor, Roche Diagnostics) and quantitative antigenemia (Monofluor pp65, Sanofi Diagnostics) was examined for monitoring CMV viraemia. A total of 469 specimens from immunocompromised haematology and solid organ transplant patients were tested by quantitative antigenemia and qualitative PCR. Quantitative PCR (QPCR) was performed on the 245 specimens in which CMV DNA was detected by qualitative PCR. To exclude any effect due to specific anti-CMV treatment, analysis of antigenemia and QPCR results was only performed on the 164 of 245 specimens collected from patients not on ganciclovir or foscarnet treatment. Forty seven specimens had <400 CMV copies/mL and a negative antigen result, four specimens were antigen positive (all between 1 to 10 positive CMV cells/2 x 10(5) leucocytes) and had <400 CMV copies/mL. Fifty-one specimens had a CMV viral load > or = 400 copies/mL and a negative antigen result and 62 specimens had a CMV viral load > or = 400 copies/mL and a positive antigen. The viral load was shown to be as high as 43,000 copies/mL in some patients with a negative antigen and occurred in non-neutropenic patients. The correlation coefficient for antigen and QPCR results for specimens from bone marrow transplant patients, was 0.69 with an average CMV viral load of 3,200 copies/mL (SEM = 800) and an average antigen of nine positive CMV cells/2 x 10(5) leucocytes (SEM = 3). In the corresponding solid organ transplant group, the correlation coefficient for antigen and QPCR results was 0.71 with an average CMV viral load of 9,900 copies/mL (SEM = 2,100) and an average antigen of 26 positive CMV cells/2 x 10(5) leucocytes (SEM = 6). Both the average viral load and the average antigen result in specimens from solid organ transplant patients, were significantly higher than the average viral load and antigen result in the corresponding group of bone marrow transplant patients (Two-Sample-for-Means z-Test, P = 0.001 and P = 0.003, respectively). The differences in the kinetics of the two assays in monitoring CMV and their ability to predict CMV disease was also assessed in a sub-group of patients. In conclusion, the two assays used in this study do not always show parallel changes in CMV viral load, but may be complementary for the diagnosis and management of CMV disease. The observation that non-neutropenic patients can have a high viral load in plasma and a negative antigenemia has implications for laboratories using antigenemia alone to monitor patients for CMV disease.

Prophylaxis strategies for solid-organ transplantation

In addition to the net state of immunosuppression, the risk of infection after transplantation is largely determined by the transplant recipient's epidemiologic exposures. Potential sources of infection in the transplant recipient include the environment and the recipient's endogenous flora. This article presents aspects of prevention of infection after solid-organ transplantation such as avoidance of epidemiologic exposures, antibacterial prophylaxis, prophylaxis for tuberculin-positive transplant recipients, and prophylaxis against infections with Pneumocystis carinii and Toxoplasma gondii.

Infectious complications of solid organ transplantations

The rate of infectious complications in SOT recipients has declined dramatically. As improvements in immunosuppressive therapy, surgical techniques, and diagnostics and antimicrobial treatment continue, further declines in infectious complications are expected. Refinements to preemptive therapy for high-risk patients are likely to contribute further to this decrease. Further investigation is required to define what role various infectious agents play in chronic allograft injury and rejection.

[Infectious complications associated with liver transplantation: analysis of 104 patients]

OBJECTIVE

Infectious complications are the main cause of morbidity and mortality during the first year after liver transplantation. The aim of the present study was to determine the incidence, microorganisms and factors associated with the development of infectious complications.

PATIENTS AND METHOD

Retrospective analysis of infectious episodes during the first year after transplantation in 104 patients undergoing transplantation between April 1995 and December 1996. The various clinical variables related to the pre-transplant disease, the surgical intervention and post-transplant evolution were evaluated with the aim of identifying predictive factors for the development of bacterial infectious complications.

RESULTS

During the first year, 51 patients (49%) presented 111 infectious episodes. The most frequent infections were bacterial (66%); 21% were cytomegalovirus infections and 22% were fungal. The incidence of bacterial infections was highest during the first month (80% of all infectious episodes in this period). Two variables were independently associated with the development of bacterial infections in the first month following transplantation: prolonged ischemia of the graft (p = 0.002) and length of stay in the intensive care unit (p = 0.002). Infectious complications caused 8 of the 11 deaths that occurred during the 1-year follow-up. Mortality associated with invasive fungal infections was 100%.

CONCLUSIONS

Although the overall incidence of infections and associated mortality has decreased, it remains the main cause of mortality and morbidity in the first year after transplantation.

Anaesthesia for patients with a transplanted organ

Increasing numbers of individuals leading normal lives have transplanted organs. They may appear in any hospital for treatment of trauma or general diseases. Common anaesthesia methods can be used for these patients, but safe conduct of anaesthesia requires knowledge of the immunosuppression, risk factors, and altered physiology or drug actions. This article reviews the anaesthesia-related literature on patients with transplanted organs.

Direct visualization and quantitation of cytomegalovirus-specific CD8+ cytotoxic T-lymphocytes in liver transplant patients

BACKGROUND

CMV infection remains a significant clinical problem in the context of LT. Changes in the magnitude of the CMV-specific CTL response after LT have not previously been assessed but may be important in determining the outcome of CMV infection.

METHOD

We used a fluorescent HLA-B*0702-CMV peptide tetrameric complex to directly visualize and quantitate CMV-specific CD8+ CTL both in immunosuppressed patients after LT and in immunocompetent controls.

RESULTS

CMV-specific CD8+ CTL, at a frequency ranging from 0.1 to 5.8% of CD8+, were detected in the peripheral blood of 22 of 25 B*0702, CMV immunoglobulin G seropositive individuals, with no difference observed between immunocompetent controls and patients >3 years after LT. In CMV seropositive LT recipients who did not have symptomatic CMV infection during the first 3 months after LT, CMV-specific CD8+ CTL magnitude initially decreased, then increased up to 5 times higher than pre-LT levels within 3 months. Two CMV seronegative recipients of seropositive donors had symptomatic CMV infection in association with high viral load. In both patients, no CD8+ CTL response was detected before the onset of symptoms, and a reduction in viral load was observed during antiviral therapy. However, polymerase chain reaction negativity was achieved only when a demonstrable CMV-specific CD8+ CTL response was generated. Responses were never observed in asymptomatic CMV seronegative patients.

CONCLUSIONS

We suggest that the generation of CMV-specific CD8+ CTL may be driven by, and seems to coincide with the suppression of, viral reactivation. Direct monitoring of CMV-specific CD8+ CTL using an HLA-peptide tetramer may prove to be of value in the management of patients after LT.

Application of viral-load kinetics to identify patients who develop cytomegalovirus disease after transplantation

BACKGROUND

Cytomegalovirus (CMV) continues to be a major problem post-transplantation; early markers for predicting patients at risk of CMV disease are needed. Peak CMV load in the blood correlates with CMV disease but frequently occurs too late to provide prognostic information.

METHODS

359 transplant recipients (162 liver, 87 renal, and 110 bone marrow) were prospectively monitored for CMV DNA in the blood with qualitative and quantitative PCR. 3873 samples were analysed. The CMV load in the first PCR-positive sample and the rate of increase in CMV load in blood during the initial phase of replication were assessed as risk factors for CMV disease using logistic regression.

FINDINGS

127 of the 359 patients had CMV DNA in the blood and 49 developed CMV disease. Initial viral load correlated significantly with peak CMV load (R2=0.47, p=<0.001) and with CMV disease (odds ratio 1.82 [95% CI 1.11-2.98; p=0.02; 1.34 [1.07-1.68], p=0.01, and 1.52 [1.13-2.05], p=0.006, per 0.25 log10 increase in viral load for liver, renal, and bone-marrow patients, respectively). The rate of increase in CMV load between the last PCR-negative and first PCR-positive sample was significantly faster in patients with CMV disease (0.33 log10 versus 0.19 log10 genomes/mL daily, p<0.001). In multivariate-regression analyses, both initial CMV load and rate of viral load increase were independent risk factors for CMV disease (1.28 [1.06-1.52], p=0.01, per 0.25 log10 increase in CMV load and 1.52 [1.06-2.17], p=0.02, per 0.1 log10 increase in CMV load/mL daily, respectively).

INTERPRETATION

CMV load in the initial phase of active infection and the rate of increase in viral load both correlate with CMV disease in transplant recipients; in combination, they have the potential to identify patients at imminent risk of CMV disease.

[Infection after orthotopic liver transplantation: analysis of the first 120 consecutive cases]

OBJECTIVE

To report the infectious complications and presentation time of the first 120 consecutive liver transplants performed at our institution.

METHODS

Prospective study of infectious complications among 120 consecutive adult patients who received orthotopic liver transplantation at Hospital de Cruces, from February 1996 to November 1998. Two patients received a renal transplant concomitantly. The same surveillance protocols were used for all patients and the criteria used to define infections were those reported by other authors.

RESULTS

The group consisted of 120 patients, 95 males and 25 females. The age ranged from 20 and 66 years (mean: 54 +/- 9 years). The indications for transplantation included alcoholic cirrhosis (47%), HCV cirrhosis (20%), hepatocellular carcinoma (17.5%), fulminant hepatitis (6%), primary biliary cirrhosis (2.5%) and miscellaneous conditions (7%). Three patients required retransplantation. Acute rejection was histologically diagnosed in 38 patients (31%). None of the patients had corticosteroid-resistant rejection. Fifty-one patients (42.5%) developed 76 episodes of severe infection, which included: 48 episodes of bacterial infection among 33 patients (27.5%), tuberculosis in 7 patients (6%), 9 episodes of fungal infection among 8 patients (7%) and cytomegalovirus (CMV) infection among 8.5% of patients. No patient developed Pneumocystis carinii pneumonia. Fifteen (12.5%) patients died: six (12.5%) with active infection, and in four of them the infection was considered the cause of death.

CONCLUSIONS

Infection rates due to bacteria and fungi were similar to those reported in the literature. A high rate of tuberculosis was found, which possible correlated with the high incidence of this disease in the general population. The low incidence of CMV infection was probably due to the preemptive therapy with gancyclovir. Trimethoprim-sulfamethoxazol prophylaxis against Pneumocystis carinii was highly effective.

The economic impact of cytomegalovirus infection after liver transplantation

BACKGROUND

We studied the economic impact of cytomegalovirus (CMV) disease and its effective reduction with antiviral prophylaxis in liver transplant recipients.

METHOD

Analysis of institutional charge data accumulated during a prospective, randomized, controlled trial comparing oral acyclovir 800 mg four times daily for 120 days (ACV) and intravenous ganciclovir 5 mg/kg every 12 h for 14 days followed by ACV for 106 days (GCV) was performed.

RESULTS

Liver transplant recipients who developed CMV disease had significantly higher charges (median: $148,300) than those who developed asymptomatic CMV infection ($119,600) or experienced no CMV infection ($114,100) (P<0.01). A multiple linear regression analysis indicated that CMV disease is associated with a 49% increase in charges, independent of other factors influencing increased hospitalization charges. In CMV-seronegative patients who received a CMV-seropositive donor organ, GCV prophylaxis was associated with a significant reduction in charges, as compared to ACV prophylaxis ($113,900 vs. $153,300, respectively; P=0.02).

CONCLUSIONS

CMV disease is an independent risk factor for increased resource utilization associated with liver transplantation. The use of an effective prophylactic antiviral regimen provides savings in health care resources, particularly in patients at high risk for developing CMV disease.

Dosing of intravenous ganciclovir for the prophylaxis and treatment of cytomegalovirus infection in solid organ transplant recipients

BACKGROUND

The optimal regimen for the prevention and treatment of cytomegalovirus (CMV) disease in solid organ transplant recipients remains to be defined, particularly for patients with abnormal or changing renal function.

METHODS

A prospective trial was conducted in patients receiving i.v. ganciclovir using a standardized dosing nomogram that corrects for renal function. Steady state peak (P) and trough (T) serum levels were determined by high-performance liquid chromatography and correlated with therapeutic outcomes and toxicities attributable to ganciclovir.

RESULTS

Over the study period, 44 individuals received ganciclovir prophylaxis (5 mg(kg/day) and 25 patients were treated (5 mg/kd q12 hr) for symptomatic CMV disease. Ganciclovir levels (microg/ml+/-SD) achieved in prophylaxis were P: 7.98+/-3.34, T: 3.03+/-2.63; and in treatment were P: 9.00+/-3.72, T: 2.65+/-1.82. Despite corrections for renal dysfunction, undialyzed patients with serum creatinine >3.0 mg/dl had trough levels in excess of the population mean (T: range 3-8 microg/ml). Failure of prophylaxis (disease) or therapy (relapse) occurred in 14 patients; 8 of these were at risk for primary infection (donor CMV seropositive, recipient seronegative, P<0.01). Patients at greatest risk for relapse after treatment of CMV disease were liver transplant recipients, patients with ganciclovir-resistant viral isolates, and renal patients with six antigen MHC donor-recipient mismatches.

CONCLUSIONS

This trial demonstrates the efficacy of a nomogram for ganciclovir dosing during renal dysfunction; reduced doses can be used for prophylaxis for undialyzed patients with renal dysfunction (1.25 mg/kg/day for Cr > or =3.0, 1.25 mg/kg QOD for Cr > or =5.0). Some groups of transplant recipients may require more intensive anti-CMV regimens.

Cost-effectiveness of different strategies of cytomegalovirus prophylaxis in orthotopic liver transplant recipients

Cytomegalovirus (CMV) is an important cause of morbidity and mortality in liver transplant recipients and several different strategies of CMV chemoprophylaxis are in practice. A cost-effective analysis was performed to compare these strategies. A hypothetical cohort of liver transplant recipients was followed up for a year posttransplantation in a Markov model, as they made possible transitions to different states of health with respect to CMV infection and disease. Different strategies of chemoprophylaxis were compared. Cost per patient, yield in terms of gain in quality-adjusted stages, amount of time spent in the state of CMV disease, and CMV-related mortality were the outcome measures compared. Oral ganciclovir administered universally to all transplant recipients was the most favored strategy. Restricting prophylaxis to defined high-risk groups or extending the duration of prophylaxis beyond 3 months did not improve cost-effectiveness. The strategy of short-term, oral ganciclovir-based chemoprophylaxis for CMV in liver transplant recipients is cost-effective by current standards of healthcare interventions.

Etiology and microbial patterns of pulmonary infiltrates in patients with orthotopic liver transplantation

STUDY OBJECTIVE

To evaluate the etiology and microbial patterns of pulmonary infiltrates in liver transplant patients using a bronchoscopic diagnostic approach and the impact of diagnostic results on antimicrobial treatment decisions.

DESIGN

A prospective cohort study.

SETTING

A 1,000-bed tertiary-care university hospital.

PATIENTS AND METHODS

Fifty consecutive liver transplant patients with 60 episodes of pulmonary infiltrates (33 episodes during mechanical ventilation) were studied using flexible bronchoscopy with protected specimen brush (PSB) and BAL.

RESULTS

A definite infectious etiology was confirmed in 29 episodes (48%). Eighteen episodes corresponded to probable pneumonia (30%), 10 episodes had noninfectious etiologies (17%), and 3 remained undetermined (5%). Opportunistic infections were the most frequent etiology (16/29, 55%, including 1 mixed etiology). Bacterial infections (mainly Gram-negative) accounted for 14 of 29 episodes (48%), including 1 of mixed etiology. The majority of bacterial pneumonia episodes (n = 10, 71%) occurred in period 1 (1 to 28 days posttransplant) during mechanical ventilation, whereas opportunistic episodes were predominant in periods 2 and 3 (29 to 180 days and > 180 days posttransplant, respectively; n = 14, 82%). Microbial treatment was changed according to diagnostic results in 21 episodes (35%).

CONCLUSIONS

Microbial patterns in liver transplant patients with pulmonary infiltrates corresponded to nosocomial, mainly Gram-negative bacterial pneumonia in period 1, and to opportunistic infections in period 2 and, to a lesser extent, period 3. A comprehensive diagnostic evaluation including PSB and BAL fluid examination frequently guided specific antimicrobial therapy.

New strategies for prevention and therapy of cytomegalovirus infection and disease in solid-organ transplant recipients

In the past three decades since the inception of human organ transplantation, cytomegalovirus (CMV) has gained increasing clinical import because it is a common pathogen in the immunocompromised transplant recipient. Patients may suffer from severe manifestations of this infection along with the threat of potential fatality. Additionally, the dynamic evolution of immunosuppressive and antiviral agents has brought forth changes in the natural history of CMV infection and disease. Transplant physicians now face the daunting task of recognizing and managing the changing spectrum of CMV infection and its consequences in the organ recipient. For the microbiology laboratory, the emphasis has been geared toward the development of more sophisticated detection assays, including methods to detect emerging antiviral resistance. The discovery of novel antiviral chemotherapy is an important theme of clinical research. Investigations have also focused on preventative measures for CMV disease in the solid-organ transplant population. In all, while much has been achieved in the overall management of CMV infection, the current understanding of CMV pathogenesis and therapy still leaves much to be learned before success can be claimed.

Human herpesviruses 6 and 7 as potential pathogens after liver transplant: prospective comparison with the effect of cytomegalovirus

Because cytomegalovirus (CMV) is an important opportunistic infection after liver transplant, we conducted a prospective study to see if the same applied to human herpesviruses (HHV)-6 and -7. We used polymerase chain reaction (PCR) methods optimised to detect active, not latent, infection and studied patients not receiving antiviral prophylaxis for CMV. Post-transplant, 536 blood samples were tested by PCR (median 7; range 4-50). Active infection with CMV was detected in 28/60 (47%), HHV-6 in 19/60 (32%), and HHV-7 in 29/60 (48%) of patients. The PCR-positive samples were tested by quantitative-competitive PCR to measure the virus load of each betaherpesvirus. The median peak virus load for CMV was significantly greater than that for HHV-6 or HHV-7. Detailed clinicopathological analyses for the whole population showed that CMV and HHV-6 were each significantly associated with biopsy-proven graft rejection. Individual case histories suggested that HHV-6 and HHV-7 may be the cause of some episodes of hepatitis and pyrexia. It is concluded that HHV-6 is a previously unrecognized contributor to the morbidity of liver transplantation, that HHV-7 may also be important and that both viruses should be included in the differential diagnosis of graft dysfunction.

Broadsheet. Number 50: Diagnosis of human cytomegalovirus infection and disease

Human cytomegalovirus (CMV) remains an important cause of illness in immunocompromised individuals and the most common viral cause of congenital malformation. The tests available for diagnosis of CMV include serology, antigen detection, virus culture, tissue histopathology and nucleic acid detection. The diagnosis of CMV remains difficult because of the issues of virus latency, virus infection versus clinical disease and virus reactivation. The tests available and the use of these tests are undergoing significant changes. This Broadsheet presents a review of these tests, particularly in the diagnosis of congenital infection and infection in pregnant women and immunocompromised individuals.

Relationship between herpesviruses and adult periodontitis and periodontopathic bacteria

BACKGROUND

Various mammalian viruses and specific bacteria seem to play important roles in the pathogenesis of human periodontitis. This study examined the relationship between subgingival herpesviruses and periodontal disease and potential periodontopathic bacteria in 140 adults exhibiting either periodontitis or gingivitis.

METHODS

A nested-polymerase chain reaction (PCR) method determined the presence of Epstein-Barr virus type 1 and type 2 (EBV-1, EBV-2), human cytomegalovirus (HCMV), and herpes simplex virus (HSV) and a 16S rRNA PCR detection method identified Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola.

RESULTS

Using a logistic analysis, EBV-1 showed significant positive association with P. gingivalis (odds ratio [OR] 3.37), and with coinfections of P. gingivalis and P. intermedia (OR 4.03); P. gingivalis and B. forsythus (OR 3.84); P. gingivalis and T. denticola (OR 4.17); P. gingivalis, B. forsythus, and T. denticola (OR 4.06); and P. gingivalis, P. nigrescens, and T. denticola (OR 3.29). EBV-1 also showed positive association with severe periodontitis (OR 5.09), with increasing age (OR 1.03), and with periodontal probing depth at the sample sites (OR 1.77). HCMV was positively associated with coinfections of P. gingivalis and P. nigrescens (OR 3.23); P. gingivalis, B. forsythus, and P. nigrescens (OR 3.23); and P. gingivalis, P. nigrescens, and T. denticola (OR 2.59); with severe periodontitis (OR 4.65); and with age (OR 1.03). Patients with mixed viral infections revealed significant associations with P. gingivalis (OR 2.27), and with coinfections of P. gingivalis and B. forsythus (OR 2.06); P. gingivalis and P. nigrescens (OR 2.91); P. gingivalis, B. forsythus, and P. nigrescens (OR 2.91); and P. gingivalis, P. nigrescens, and T. denticola (OR 2.70) with the clinical diagnosis of slight (OR 3.73), moderate (OR 3.82), or severe periodontitis (OR 4.36), and with probing depth at the sample sites (OR 1.39). HSV and EBV-2 showed no significant associations with any of the variables tested.

CONCLUSIONS

The results indicate that subgingival EBV-1, HCMV, and viral coinfections are associated with the subgingival presence of some periodontal pathogens and periodontitis. Herpesviruses may exert periodontopathic potential by decreasing the host resistance against subgingival colonization and multiplication of periodontal pathogens.

Absence of teratogenicity of oral ganciclovir used during early pregnancy in a liver transplant recipient

BACKGROUND

Ganciclovir (GCV) is effective for prevention of cytomegalovirus (CMV) disease. In animals it may cause some teratogenicity. There is little information on the effect of GCV on a human fetus.

METHODS

The chart of a liver transplant recipient who received oral GCV during the first trimester was reviewed as was the published literature.

RESULTS

There was no evidence of teratogenicity in the baby or in a case reported elsewhere.

CONCLUSIONS

GCV has been used in a few female transplant recipients without untoward effects. The still uncertain risk of short term and long term teratogenicity, however, must be weighed against the risk of CMV disease in the recipient and the development of congenital CMV in the baby.

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.

Oral ganciclovir dosing in transplant recipients and dialysis patients based on renal function

BACKGROUND

An oral formulation of ganciclovir (GCV) was recently approved for the prevention of cytomegalovirus disease in solid organ transplant recipients. This study was designed to determine the bioavailability of GCV and to test a dosing algorithm in transplant and dialysis patients with different levels of renal function.

METHODS

Pharmacokinetic studies were carried out in 23 patients who were either a recipient of an organ transplant or on hemodialysis. Drug dosing was established by the following algorithm based on calculated creatinine clearance (CrCl): CrCl = [(140-age) x body weight]/(72 x Cr) x 0.85 for women that is, CrCl >50 ml/min, 1000 mg every 8 hr; CrCl of 25-50 ml/min, 1000 mg every 24 hr; CrCl of 10-24 ml/ min, 500 mg every day; CrCl < 10 ml/min (or on dialysis), 500 mg every other day after dialysis. GCV was taken within 30 min after a meal. The patients received oral GCV for between 12 days and 14 weeks. Serum specimens (or plasma from patients on hemodialysis) obtained at steady state were analyzed for GCV concentrations by high-performance liquid chromatography. In nine of the transplant recipients, absolute bioavailability was determined by comparing GCV levels after single oral and intravenous doses of GCV.

RESULTS

The following GCV concentrations (mean +/-SD) were determined: with CrCl of > or =70 ml/min, the minimum steady-state concentration (Cmin) and maximum concentration (Cmax) were 0.78+/-0.46 microg/ml and 1.42+/-0.37 microg/ml, respectively, with a 24-hr area under the concentration time curve (AUC0-24) of 24.7+/-7.8 microg x hr/ml; with CrCl of 50-69 ml/min, the Cmin and Cmax were 1.93+/-0.48 and 2.57+/-0.39 microg/ml, respectively, with an AUC0-24 of 52.1+/-10.1 microg x hr/ml; with CrCl of 25-50 ml/min, the Cmin and Cmax were 0.41+/-0.27 and 1.17+/-0.32 microg/ml, respectively, with an AUC0-24 of 14.6+/-7.4 microg x hr/ml. For one patient with a CrCl of 23.8 ml/min, the Cmin and Cmax were 0.32 and 0.7 microg/ml, respectively, with an AUC0-24 of 10.7 microg x hr/ml. With CrCl of <10 ml/min, the mean Cmin and Cmax were 0.75+/-0.42 and 1.59+/-0.55 microg/ml, respectively, with a mean AUC0-24 of 64.6+/-18.8 microg x hr/ml. Absolute bioavailability, for the nine patients so analyzed, was 7.2+/-2.4%. For those patients with end-stage renal failure, GCV concentrations fell during dialysis from a mean of 1.47+/-0.48 microg/ml before dialysis to 0.69+/-0.38 microg/ml after dialysis.

CONCLUSIONS

The bioavailability of oral GCV in transplant patients was similar to that observed in human immunodeficiency virus-infected patients. However, levels between 0.5 and 1 microg/ml (within the IC50 of most cytomegalovirus isolates) could be achieved with tolerable oral doses. The proposed dosing algorithm resulted in adequate levels for patients with CrCl greater than 50 ml/min and for patients on dialysis. For patients with CrCl between 10 and 50 ml/min, the levels achieved were low and these patients would likely benefit from increased doses.

Significance of cytomegalovirus for long-term survival after orthotopic liver transplantation: a prospective derivation and validation cohort analysis

BACKGROUND

Cytomegalovirus (CMV) infection and disease has been found to be associated with decreased graft and patient survival among heart transplant recipients. We sought to explore the effect of CMV infection and disease on long-term survival in orthotopic liver transplant (OLT) recipients using a derivation and validation cohort.

METHODS

For derivation-validation modeling, we used data collected from two prospectively followed cohorts as the basis for multivariate analyses: 167 OLT recipients from the Boston Center for Liver Transplantation (the derivation set; median follow-up: 5.5 years, mortality: 40%) and an independent cohort of 294 OLT recipients from the Mayo Clinic (the validation set; median follow-up: 4.8 years, mortality: 27%).

RESULTS

Underlying liver disease other than primary biliary cirrhosis or sclerosing cholangitis, number of units of red blood cells administered during transplantation, and donor CMV seropositivity were the pre- and intratransplant variables independently associated (P<0.01) with decreased long-term survival in the derivation cohort. For variables collected up to 1 year after transplantation, the need for retransplan. tation, CMV pneumonia, invasive fungal disease, and underlying liver disease other than primary biliary cirrhosis or sclerosing cholangitis were independently associated (P<0.01) with decreased long-term survival in the derivation cohort. The magnitude of the relationship of each pre-, intra-, and posttransplant factor with survival, as measured by the relative risk, did not significantly differ between the derivation and validation cohorts. The derivation model, incorporating pre-, intra-, and posttransplant factors, had receiver operating characteristic areas of 73% and 74% for 5-year mortality in the derivation and validation cohorts, respectively.

CONCLUSIONS

Data from a derivation and an independent validation cohort demonstrate that CMV factors (reflected by either donor CMV seropositivity at transplantation, CMV pneumonia, or CMV disease within the first posttransplant year) are independently associated with decreased long-term survival in OLT recipients.

Cytomegalovirus and its association with hepatic artery thrombosis after liver transplantation

BACKGROUND

Hepatic artery thrombosis (HAT) is a cause of morbidity and graft loss in approximately 7% of patients after an orthotopic liver transplantation (OLT). Although technical problems are often thought to be the cause of HAT, in general the etiology remains unclear. Because cytomegalovirus (CMV) can infect endothelial cells in vitro and lead to a rapid procoagulant response, it can be hypothesized that, in the absence of CMV antibodies, latent CMV in an allograft may become activated and promote or contribute to vascular thrombosis. Therefore, the purpose of this study was to examine the relationship between CMV serology of the donor and recipient with the development of HAT after OLT.

METHODS

Between July 1988 and November 1995 (University of Wisconsin era), 490 OLTs were performed in 413 patients. Subsequently, four patients were excluded in whom the CMV serology results of the donor were not available. Sixteen of the 409 patients developed HAT within 30 days after liver transplantation. The control group consisted of the other 393 patients.

RESULTS

The incidence of HAT was 12.5% in 64 CMV D+R- patients and 0% in 52 CMV D-R- patients. However, in the other combinations (D+R+ and D-R+), the incidence was only 2.8% (P = 0.005). Eight of the 16 patients with HAT belonged to the CMV D+R- group.

CONCLUSIONS

We conclude that CMV-seronegative patients receiving a seropositive allograft may be at risk for early HAT. Seropositivity of the donor alone and of the recipient alone was not significantly related to the incidence of HAT. Prophylactic treatment with ganciclovir and/or anticoagulation should be evaluated to prevent this complication.

Active cytomegalovirus infection in human periodontitis

This study used the reverse transcription polymerase chain reaction method to determine mRNA transcription of subgingival human cytomegalovirus (HCMV) in six adult and three localized juvenile periodontitis patients. The oligonucleotide primers targeted the major capsid protein gene to determine active HCMV infection. HCMV major capsid protein transcript was detected in deep periodontal pockets of two adult and two localized juvenile periodontitis patients but not in any shallow periodontal sites. The findings suggest that active HCMV replication can occur in periodontal sites. Further studies are necessary to establish whether periodontal reactivation of HCMV correlates with the initiation or progression of destructive periodontal disease.

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.

Randomised trial of efficacy and safety of oral ganciclovir in the prevention of cytomegalovirus disease in liver-transplant recipients. The Oral Ganciclovir International Transplantation Study Group [corrected]

BACKGROUND

Cytomegalovirus (CMV) disease is a frequent cause of serious morbidity after solid-organ transplantation. The prophylactic regimens used to prevent CMV infection and disease have shown limited benefit in seronegative recipients. We studied the safety and efficacy of oral ganciclovir in the prevention of CMV disease following orthotopic liver transplantation.

METHODS

Between December, 1993, and April, 1995, 304 liver-transplant recipients were randomised to receive oral ganciclovir 1000 mg or matching placebo three times a day. Seronegative recipients of seronegative livers were excluded. Study drug was administered as soon as the patient was able to take medication by mouth (no later than day 10) until the 98th day after transplantation. Patients were assessed at specified times throughout the first 6 months after surgery for evidence of CMV infection, CMV disease, rejection, opportunistic infections, and possible drug toxicity.

FINDINGS

The Kaplan-Meier estimate of the 6-month incidence of CMV disease was 29 (18.9%) of 154 in the placebo group, compared with seven (4.8%) of 150 in the ganciclovir group (p < 0.001). In the high-risk group of seronegative recipients (R-) of seropositive livers (D+), incidence of CMV disease was 11 (44.0%) of 25 in the placebo group, three (14.8%) of 21 in the ganciclovir group (p = 0.02). Significant benefit was also observed in those receiving antibodies to lymphocytes, where the incidence of CMV disease was 12 (32.9%) of 37 in the placebo group and two (4.6%) of 44 in the ganciclovir group (p = 0.002). Oral ganciclovir reduced the incidence of CMV infection (placebo 79 [51.5%] of 154; ganciclovir 37 [24.5%] of 150; p < 0.001) and also reduced symptomatic herpes-simplex infections (Kaplan-Meier estimates: placebo 36 [23.5%] of 154; ganciclovir five [3.5%] of 150; p < 0.001).

INTERPRETATION

Oral ganciclovir is a safe and effective method for the prevention of CMV disease after orthotopic liver transplantation.

Prophylaxis of cytomegalovirus infection in liver transplantation: a randomized trial comparing a combination of ganciclovir and acyclovir to acyclovir. NIDDK Liver Transplantation Database

BACKGROUND

The optimal prophylactic regimen to prevent cytomegalovirus (CMV) infection and disease in orthotopic liver-transplant patients remains to be established. We tested whether a combination of intravenous ganciclovir (GCV) followed by high dosages of oral acyclovir (ACV) for 4 months provided a higher degree of protection from CMV than oral ACV alone.

METHODS

One hundred sixty-seven liver-transplant recipients were randomized to receive 120 days of antiviral treatment starting at the time of transplantation consisting of either ACV 800 mg orally four times daily (n=84) or 14 days of GCV 5 mg/kg intravenously every 12 hr followed by oral ACV 800 mg four times daily (n=83). Prospective laboratory and clinical surveillance was performed to determine primary endpoints (onset of CMV infection and CMV disease) and secondary endpoints (rates of fungal and bacterial infection, allograft rejection, and survival after transplantation). One-year event rates are presented as cumulative percentages.

RESULTS

During the first year after transplantation, CMV infection developed in 57% of patients treated with ACV and in 37% of patients treated with GCV + ACV (P=0.001). CMV disease developed in 23% of patients treated with ACV and in 11% of patients treated with GCV + ACV (P=0.03). In seronegative recipients of allografts from CMV-seropositive donors (D+/R-), CMV disease developed in 58% of patients treated with ACV and in 25% of patients treated with GCV + ACV (P=0.04). In the D+/R- group, 54% of patients treated with ACV and 17% of patients treated with GCV + ACV developed infection with Candida albicans (P=0.05).

CONCLUSIONS

Prophylaxis of CMV infection in liver-transplant patients with 14 days of intravenous GCV followed by high-dosage oral ACV is more effective than high-dosage oral ACV alone at reducing CMV infection and disease, even for patients in the D+/R- CMV serological group.

Infections After Organ Transplantation

Over the last ten to fifteen years medical and surgical advances have led to lower rates of infection and infection-related mortality in transplant recipients. Despite these advances, the process whereby one diagnoses and manages infectious problems in transplant patients has become increasingly complex. Evaluation of transplant patients with infections requires a good understanding of the intricacies of modern immunosuppressive therapy and both the typical and atypical clinical manifestations of many conventional and opportunistic pathogens. In particular, it is incumbent upon the clinicians caring for transplant patients to be familiar with the biology of cytomegalovirus and other herpes viruses, and of the prophylactic strategies that have evolved to lessen the burden of disease from these agents. Thorough knowledge is also required of common fungal pathogens and the viruses that cause chronic hepatitis. Transplant patients also should always be evaluated in the temporal context of their transplant operation, because different diseases are prevalent at different times after transplantation. Since immunosuppressive drugs modify the clinical presentation of infections is important to maintain clinical vigilance and attend to even minor new symptoms. This chapter is designed to provide a relatively concise overview of transplant infections for intensivists or other clinicians who encounter transplant patients in their practice. The references encompass much of the classic transplant infectious disease literature; they are included, not only for citation, but as a bibliography for further study.

Cytomegalovirus disease is associated with increased cost and hospital length of stay among orthotopic liver transplant recipients

Cytomegalovirus (CMV) is a cause of considerable morbidity and mortality among orthotopic liver transplant (OLT) recipients. To study the impact of CMV on cost and hospital length of stay in this population, we undertook an analysis of a cohort of OLT recipients from four transplant centers in Boston who participated in a CMV prophylaxis trial. First posttransplant year hospital length of stay (including the hospital stay after transplantation and readmissions within 1 year after transplantation) was available for all 141 patients included in the study. In a multiple linear regression model bacteremia (P=0.0001), CMV disease (P=0.0007), abdominal reexploration (excluding retransplantation) (P=0.0070), recipient age < or = 16 years (P=0.0352), and the number of units of blood products (red blood cells, platelets, or fresh frozen plasma) administered during transplantation (P=0.0523) were shown to be independently associated with longer first posttransplant year hospital length of stay. Cost data for in-hospital care for the year beginning with admission for liver transplantation were available for 66 OLT recipients. Using a multiple linear regression model, development of CMV disease (P=0.0001), the number of units of blood products administered during transplantation (P=0.0001), bacteremia (P=0.0002), decreased pretransplant renal function (estimated by creatinine clearance) (P=0.0109), and need for retransplantation (P=0.0619) were shown to be independently associated with higher cost. These data strongly suggest that CMV disease has a direct impact on cost and hospital length of stay in liver transplantation.

Enhanced (cytomegalovirus) viral replication associated with septic bacterial complications in liver transplant recipients

BACKGROUND

Complications of the biliary anastomosis are the principal cause of clinically serious bacterial sepsis in liver transplant recipients. Reported series suggest an association of bacterial and fungal infection with cytomegalovirus (CMV) infection, although the mechanism of this association is unclear.

METHODS

We examined the association of serious bacterial sepsis with CMV replication in a cohort of 106 consecutive liver transplant recipients. Sequentially collected buffy coats were examined with a polymerase chain reaction (PCR) assay that has been shown to have good predictive value for the development of CMV infection. For selected patients, CMV-specific IgM response and serum tumor necrosis factor-alpha (TNF-alpha) were also measured.

RESULTS

Ten of 13 patients with serious bacterial sepsis developed buffy coat PCR positivity, compared with 26 of 93 patients without bacterial sepsis (chi-square, P<0.001). Ten of 10 septic recipients with a seropositive liver donor developed PCR positivity. For 9 of 10 recipients, bacterial sepsis developed before PCR positivity. Bacterial sepsis was associated with high serum levels of TNF-alpha. Immune response to CMV (reflected by the appearance CMV-specific IgM) was apparently affected by bacterial sepsis, and IgM response was not observed for the three septic patients who died during the study period.

CONCLUSIONS

We conclude that CMV replication is encouraged by serious bacterial sepsis. Replication may be promoted by high antecedent levels of TNF-alpha, and/or by poor immune response to CMV in the context of serious bacterial infection.

A comparison of cytomegalovirus and community respiratory viruses in immunocompromised patients

Infection of organ transplant recipients with herpesviruses, especially cytomegalovirus (CMV), has been an important barrier to successful transplantation. Measures to prevent CMV infection have evolved based on the biology and epidemiology of the virus. Recently, community-acquired respiratory viruses have been recognized as an important cause of morbidity and mortality in immunocompromised hosts. It is unlikely that the strategies used to prevent and treat CMV disease will be applicable to the community respiratory viruses, owing to their different biology and epidemiology. Basic epidemiologic questions that focus on defining risk factors for disease and death from community-acquired respiratory viruses in the immunocompromised host have not been answered. The lack of established risk factors and a rapid "gold standard" diagnostic test for community-acquired respiratory viruses in the immunocompromised host has had a negative impact on the diagnosis and treatment of these infections. The study of CMV disease in organ transplant patients may serve as a blueprint for studies of community respiratory virus infections.

Patterns of viremia in liver transplant recipients with symptomatic cytomegalovirus infection

Cytomegalovirus (CMV) titer in blood seems to be the principal determinant of clinical symptoms in immunosuppressed patients. We have developed an assay for quantitation of CMV DNA in serum. The assay requires the coamplification by polymerase chain reaction (PCR) of extracted serum DNA with 1000 molecules of mutated internal standard DNA, and then an ELISA detection system. We examined 133 paired buffy coats and sera from 15 patients with symptomatic infection. Sera were examined by quantitative PCR, and buffy coats were examined by qualitative PCR (with a detection threshold of approximately 40 copies per 150,000 cells). Serum viral titers peaked during the seventh week after transplant (median day 40, range 26-58) at about the time of symptom onset. Mean viral titer measured during the seventh week was 1.2 x 10(5) copies per milliliter of serum (standard error 6.5 x 10(4). Buffy-coat PCR results were generally concordant with results of serum PCR (overall concordance 103/133=77.4%). Serum CMV titer fell, as symptoms resolved with reduction of immunosuppression and specific antiviral therapy. High titers and poor response to antiviral therapy were observed in the context of excessive immunosuppression and bacterial sepsis. Measurement of serum CMV titer may be useful for the management of immunosuppressed transplant recipients, and provides a tool for the better understanding of factors that enhance or inhibit viral replication.

Infections in solid-organ transplant recipients

Solid-organ transplantation is a therapeutic option for many human diseases. Infections are a major complication of solid-organ transplantation. All candidates should undergo a thorough infectious-disease screening prior to transplantation. There are three time frames, influenced by surgical factors, the level of immunosuppression, and environmental exposures, during which infections of specific types most frequently occur posttransplantation. Most infections during the first month are related to surgical complications. Opportunistic infections typically occur from the second to the sixth month. During the late posttransplant period (beyond 6 months), transplantation recipients suffer from the same infections seen in the general community. Opportunistic bacterial infections seen in transplant recipients include those caused by Legionella spp., Nocardia spp., Salmonella spp., and Listeria monocytogenes. Cytomegalovirus is the most common cause of viral infections. Herpes simplex virus, varicella-zoster virus, Epstein-Barr virus and others are also significant pathogens. Fungal infections, caused by both yeasts and mycelial fungi, are associated with the highest mortality rates. Mycobacterial, pneumocystis, and parasitic diseases may also occur.

Cytokine pattern during rejection and infection after liver transplantation--improvements in postoperative monitoring?

Despite improvements in immunosuppression, rejection occurs in 50% of liver transplant patients and may cause significant morbidity. The most frequent cause of death after liver transplantation is severe infection. Determination of the cytokine network may lead to earlier detection of patients at risk for severe rejection and infection. For this purpose, 81 patients with 85 liver transplants were monitored for cytokines and neopterin on a daily basis. During the first postoperative month, 28 patients (34.6%) developed acute rejection; 14 patients were successfully treated with methylprednisolone (steroid-sensitive rejection), while 14 patients required additional treatment with FK506 and OKT3 (steroid-resistant rejection). Ten patients developed severe infections, and 11 patients experienced asymptomatic cholangitis. Patients with an uneventful postoperative course (n=37) were the control group. One-year patient survival was 88.9%: 1 patient died because of chronic rejection and Pseudomonas urosepsis; a further 4 patients died of aspergillus pneumonia and bacterial sepsis. Soluble TNF-RII, sIL-2R-, and IL-10 levels were significantly elevated 3 days prior to or at the onset of acute steroid-resistant rejection (P < or = 0.01 versus steroid-sensitive rejection and on uneventful postoperative course). An increase in IL-8, neopterin, and sTNF-RII was indicative of severe infection 3 days prior to onset of infection. In this group of patients, a simultaneous increase in IL-10 indicated a lethal outcome of severe infection. During the second week of acute steroid-resistant rejection and lethal infection, a significant rise in IL-1beta, IFN-gamma, and IL-6 was observed (P < or = 0.01 versus control groups). The different patterns in neopterin- and cytokine-increase could differentiate between severe rejection and severe infection. Furthermore, the increase in these parameters indicated severe rejection--i.e., steroid resistance at the onset of acute rejection--which could prompt us to initiate rescue therapy immediately. The ability to detect patients at risk for severe or lethal infection may result in intensified infectious screening and more aggressive antiinfectious treatment. Therefore, routine monitoring of these parameters may lead to changes in therapeutic management of severe acute rejection and infection after liver transplantation.

Risk factors of invasive Candida and non-Candida fungal infections after liver transplantation

Fungal infections are associated with a high mortality rate after liver transplantation. To describe risk factors for fungal infections, 405 consecutive liver transplant recipients were analyzed. Forty-five patients (11%) developed invasive fungal infection. Median posttransplantation time to the first episode was 60 days. Pathogens were Candida species (spp) (n=24, 53%), Cryptococcus neoformans (n=10, 22%), Aspergillus spp (n=6, 13%), Rhizopus spp (n=l), and others (n=4). Presentations of infection included disseminated (n=9), intra-abdominal (n=9), esophageal (n=9), lung (n=8), blood (n=6), and central nervous system infections (n=3), and sinusitis with esophagitis (n=1). Eighteen patients (40%) with invasive fungal infection died, and 13 (72%) of these deaths were attributable to fungi. Mortality in the nonfungal infection group was 12%. Univariate analysis identified separate risk factors for Candida (intra-abdominal bleeding), Aspergillus (fulminant hepatitis), and cryptococcal (symptomatic cytomegalovirus infection) infections. In both univariate and multivariate analyses, a high intratransplant transfusion requirement and posttransplant bacterial infection were identified as significant risk factors for all types of fungal infection. The risk factor analysis reported here suggests that different pathogenic processes lead to Candida and non-Candida infection in liver transplant recipients. Their identification should prompt specific prophylactic measures to reduce morbidity and mortality in this population.

Incidence and predictors of cytomegalovirus pneumonia in orthotopic liver transplant recipients. Boston Center for Liver Transplantation CMVIG Study Group

The incidence, predictors, and outcome of cytomegalovirus pneumonia in OLT recipients have not been well defined. We conducted an analysis of prospectively collected data from 141 OLT recipients who were included as part of a randomized, placebo-controlled trial of CMV immune globulin prophylaxis. Cytomegalovirus pneumonia was diagnosed in 13 of 141 (9.2%) OLT recipients during the first year posttransplant and was associated with a higher 1-year mortality compared with those recipients without CMV pneumonia (84.6 vs. 17.2%, P=0.0001). Univariate analysis demonstrated that CMV viremia (P=0.001), invasive fungal disease (P=0.0001), donor(+)/pretransplant recipient(-) CMV serologic status (P=0.013), abdominal operation (excluding retransplantation) after liver transplantation (P=0.0027), bacteremia (P=0.0105), and advanced United Network of Organ Sharing status (P=0.023) were associated with CMV pneumonia. Cytomegalovirus viremia was diagnosed in 11 of 13 patients with CMV pneumonia at a median of 11 days (range 1-66 days) before diagnosis of CMV pneumonia. In a multivariate analysis using a time-dependent, Cox proportional hazards model, CMV viremia (RR=8.6, 95% CI 1.8-39.7, P=0.0012), invasive fungal disease (RR=6.5, 95% CI 2.1-20.3, P=0.0001), and abdominal reoperation (RR=4.4, 95% CI 1.4-13.1, P=0.0043) were found to be independent predictors of CMV pneumonia. The attributable mortality associated with CMV pneumonia within the first year after liver transplantation for the patients with CMV pneumonia was 67.4%. Intensified measures for prevention of CMV should be considered for patients at high risk of developing CMV pneumonia.

Relevance and risk factors of enterococcal bacteremia following liver transplantation

To analyze the clinical characteristics of and identify specific risk factors for enterococcal bacteremia following liver transplantation, we performed a study in 405 consecutive liver transplantation recipients prophylaxed with a selective bowel decontamination regimen. Seventy enterococcal bacteremias in 52 patients were identified. Enterococcus faecalis (50) outnumbered Enterococcus faecium isolates (18), and 49% of enterococcal bacteremias were polymicrobial. Biliary tree complications were present in 34% of enterococcal bacteremias. Of the 15 deaths (29%) among the patients with enterococcal bacteremia, 4 were directly associated with enterococcal bacteremia. In a multivariate analysis, Roux-en-Y choledochojejunostomy (P=0.005), a cytomegalovirus-seropositive donor (P=0.013), prolonged transplantation time (P=0.02), and biliary stricturing (P=0.016) were identified as significant risk factors. Other risk factors identified in a univariate analysis included primary sclerosing cholangitis (P=0.009) and symptomatic cytomegalovirus infection (P=0.008). Enterococcal bacteremia is a frequent infectious complication in liver transplantation recipients receiving selective bowel decontamination. Its association with cytomegalovirus and biliary tree abnormalities suggest specific areas for prophylactic intervention.