Stool cultures obtained before liver transplantation are useful for choice of perioperative antibiotic prophylaxis.

Bacterial infections, especially cholangitis, are still common complications after liver transplantation (LTx). During recent years, multiresistant enterococci have become a nosocomial problem in transplant units. The present prospective study on 26 patients, including 24 patients with chronic liver disease, demonstrated that enterococci were the predominant micro-organism involved in post-LTx bacterial infections. They were cultured in the feces and in other sites of 10 out of 13 (77%) patients who underwent extensive examinations. Ampicillin-resistant Enterococcus faecium strains were isolated in urine or feces of 2 of the 13 patients prior to LTx. Similarly, resistance to ampicillin and gentamicin, the empirically used antibiotics for patients with fever of unknown origin, was found in E. faecium strains in 3 and 2 patients, respectively. Moreover, multiresistant E. faecium and E. faecalis strains were demonstrated in 46% of the patients in the postoperative period (3 months). However, no vancomycin-resistant enterococci were isolated. The use of antibiotics within 4 months prior to LTx significantly increased the risk of developing ampicillin-resistant bacteria at the time of LTx and of infections with bacteria of enteric origin after LTx (P = 0.03 and 0.01, respectively). We conclude that stool and urine cultures performed prior to LTX may be useful for selecting prophylactic antibiotic regimens.

Epstein-Barr virus DNA in serum after liver transplantation--surveillance of viral activity during treatment with different immunosuppressive agents.

In immunocompromised HIV-infected and transplanted patients, there is a risk of developing Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPD) and lymphomas. EBV has previously been detected by the polymerase chain reaction (PCR) in cerebrospinal fluid from all AIDS patients with EBV-associated cerebral lymphomas. We therefore thought it would be of interest to determine whether transplant patients with extracerebral EBV-associated LPD have detectable EBV genomes in serum. Nested PCR (nPCR) showed that 58% (18/31) of liver transplant (LTX) patients had EBV DNA in 17% (21/125) of serum samples obtained within the first 3 months after LTX. In 39% (7/18) of the patients, the first EBV nPCR-positive sample was found within 2 weeks post-LTX. Basic immunosuppression with cyclosporin A or FK506 did not seem to influence the frequency of detectable EBV genomes in serum. In contrast, positive EBV nPCR correlated to secondary OKT3 treatment for severe acute rejection (P = 0.009). EBV-associated malignant lymphoma developed in three patients 2-6 months post-LTX. In all of them, EBV DNA was amplifiable within 12-14 days after LTX. The EBV antibody titers were not directly related to detectable EBV DNA in serum. We conclude that monitoring of LTX patients receiving increased immunosuppression by nPCR for EBV DNA in serum may help in the early identification of those at risk of developing EBV-associated LPD.

Polymerase chain reaction for the early diagnosis of cytomegalovirus hepatitis in liver transplant patients.

BACKGROUND: In liver transplant (LTX) patients, cytomegalovirus (CMV) hepatitis as a cause of graft dysfunction occurs in 15-25% of the patients. Polymerase chain reaction (PCR), applied to liver biopsy specimens, may increase the ability to detect CMV DNA at a local site. In this study, PCR was used to compare its relation to the development of clinical CMV hepatitis. STUDY DESIGN: Nested polymerase chain reaction (nPCR), derived from a conserved region of the CMV major immediate-early gene, was used to examine 141 frozen liver biopsies from 61 LTX patients for the presence of CMV DNA. 134 biopsies were obtained from 54 patients with pathological liver function tests within four months after transplantation. The remaining seven patient biopsies were derived from the one-year investigation after LTX and served as controls. The results were compared to virus isolation, antigen detection by immunohistology and in situ hybridization for CMV DNA of the biopsy specimens. Histological examination was performed to verify a diagnosis of viral hepatitis. RESULTS: CMV DNA was amplified in 11% (15/134) of the biopsies, corresponding to 20% (11/54) of the patients. Virus isolation revealed CMV in 5% (7/134) of the samples. None of the nPCR-negative biopsies was virus culture positive. CMV genomes were detected by nPCR more frequently than CMV hepatitis was diagnosed by using the combination of CMV-specific histopathology and/or immunohistology and/or CMV-positive virus isolation (p < 0.01). However, when this comparison was performed within individual patients, the difference was not significant (p > 0.05). If the results of in situ hybridization were included in the diagnostic criteria of CMV hepatitis, the nPCR was comparable to these, both at the biopsy and the patient levels (p > 0.1 and p > 0.05, respectively). For the diagnosis of CMV hepatitis the negative predictive value of CMV-nPCR was 1.0. The positive predictive value ranged from 0.55 to 0.82 depending on the criteria of CMV hepatitis. The nPCR also detected signs of CMV infection in the liver graft earlier than virus isolation, 11 versus 21 days, respectively, after transplantation. CONCLUSION: The frequency of CMV DNA positivity, measured by nPCR, was similar to that revealed by other combined methods. We suggest that the combined findings of histological cholangitis and/or lobulitis together with nPCR for CMV DNA can be used as a diagnostic criterion for initiation of antiviral treatment against CMV hepatitis.

Clinical use of immunohistopathologic methods for the diagnosis of cytomegalovirus hepatitis in human liver allograft biopsy specimens.

BACKGROUND: Cytomegalovirus (CMV) infections are common in liver transplant recipients, and some of the patients develop CMV hepatitis. Clinically, this condition is difficult to distinguish from acute rejection. The histologic criteria for acute liver graft rejection are well accepted, but the criteria for the histomorphologic changes in CMV hepatitis vary considerably. We have recently applied immunohistologic examinations, in situ hybridization, and virus isolation for identification of CMV in liver biopsy specimens. METHODS: CMV hepatitis was studied with repeated liver biopsies during the first 3 post-transplant months in 57 transplanted liver grafts. The histopathologic changes due to CMV were compared with those of acute rejection in 99 biopsy specimens. CMV-specific monoclonal antibodies (mAbs) were used to detect the presence of CMV antigens by means of immunofluorescence and immunoperoxidase methods. In situ hybridization for the detection of CMV-DNA was performed on the same paraffin-embedded liver specimens. In most cases, fresh, post-transplant liver specimens were also subjected to virus isolation. RESULTS: Although 60% of the liver graft donors were CMV-seropositive, CMV was rarely detected in the perioperatively obtained specimens: 1 of 36 by in situ hybridization only. None of the 21 specimens (21 patients) obtained from diseased liver grafts during the 1st post-transplant month showed evidence of CMV infection. In contrast, 8 of the 42 specimens (42 patients) obtained during the 2nd and 3rd months showed histopathologic signs of a predominant viral cholangitis (4 cases) or viral lobulitis (4 cases). The presence of CMV was ascertained in 7 of these 42 patients (17%). CONCLUSIONS: In liver transplant patients with clinical and laboratory signs of liver involvement, the identification of CMV by immunomorphologic methods and/or by virus isolation permitted the diagnosis of CMV hepatitis with the positive and negative predictive values of 0.86 and 1.0, and 1.0 and 1.0 for the former and the latter methods, respectively, as compared with histologic changes. By using immunohistopathologic techniques, it is possible to initiate antiviral therapy early in patients with CMV hepatitis.

Seroprevalence and outcome of hepatitis C in liver transplantation.

A recombinant enzyme-linked immunosorbent assay (ELISA) followed by a neutralization test (NT) and recombinant immunoblot assay (RIBA) were used for the detection of antibody to hepatitis C virus (anti-HCV) in 71 patients receiving 84 orthotopic liver grafts between 1984 and 1990. Before the liver transplantation (LTX) anti-HCV was present in six of the 71 recipients (8.5%) who were accepted for LTX because of acute or chronic liver failure. After LTX anti-HCV could not be detected in one of the patients, but it was continuously present in the others for more than 12 months. Detectable HCV antibodies were not present in the three patients who underwent LTX because of clinical evidence of fulminant NANB hepatitis. Two of 48 (4.2%) previously HCV seronegative recipients, who survived more than 3 months, seroconverted 9 and 16 months, respectively, after transplantation. The postoperative seroconversion was probably due to the transfer of virus via perioperative blood transfusions. Thus, these liver recipients may be able to respond by producing anti-HCV despite immunosuppressive therapy. None of the seven post-transplant HCV-seropositive patients developed symptoms such as icterus or fatigue, which would suggest the presence of liver insufficiency due to HCV infection. However, two of them had increased transaminase levels and histological signs of mild hepatitis. No significant difference was found in 1-year survival, prothrombin complex, albumin levels or the risk for retransplantation in post-transplant anti-HCV-seropositive patients, compared with those without detectable HCV antibodies (71% vs 69%, respectively). Thus, during the study period of 1-5 years, the clinical course of HCV infection was milder than that reported for hepatitis B infection in liver recipients.