Bacterial, mycobacterial, and protozoal infections after liver transplantation--part I

Methods of preventing bacterial sepsis and wound complications for liver transplantation

BACKGROUND

Bacterial sepsis and wound complications after liver transplantation increase mortality, morbidity, hospital stay, and overall transplant costs.

OBJECTIVES

To assess the benefits and harms of different methods aimed at preventing bacterial sepsis and wound complications in patients undergoing liver transplantation.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until June 2007.

SELECTION CRITERIA

We included only randomised clinical trials irrespective of language or publication status.

DATA COLLECTION AND ANALYSIS

We collected the data on infections, adverse effects of intervention, ITU (intensive therapy unit) stay, and hospital stay. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis and risk ratio (RR) or weighted mean difference (WMD) with 95% confidence intervals (CI) based on intention-to-treat analysis.

MAIN RESULTS

We identified seven trials for inclusion including 614 patients. Four trials compared selective bowel decontamination versus placebo or no treatment. In one trial, patients were randomised to selective bowel decontamination, active lactobacillus with fibres (probiotic with prebiotic), or to inactivated lactobacillus with fibres (prebiotic). In another trial, different doses of granulocyte-colony stimulating factor and placebo were compared. The remaining two trials compared lactobacillus with fibres versus fibres alone and early enteral feeding versus no intervention. Only one trial was of low bias-risk. There was no statistically significant difference in any outcome between the selective bowel decontamination and the control groups. Selective bowel decontamination increased incidence of cholangitis (RR 4.84, 95% CI 1.15 to 20.35), incidence of bacterial infection (RR 3.63, 95% CI 1.36 to 9.74), and hospital stay (WMD 4.00, 95% CI 3.14 to 4.86) than the participants in the combined pre- and probiotic group. Hospital stay was prolonged in the selective bowel decontamination group compared to the prebiotic group. There was a statistically significant lower occurrence of urinary infection in the pre- and probiotic group than in the prebiotic group. The number of people experiencing gram-negative bacterial infection was not significantly lower in the probiotic group (RR 0.18, 95% CI 0.03 to 1.17). The ITU stay was lower in the probiotic group (WMD -1.41 days, 95% CI -2.09 to -0.73). There were no differences in any outcomes in the other comparisons.

AUTHORS' CONCLUSIONS

Currently, there is no clear evidence for any intervention offering significant benefits in the reduction of bacterial infections and wound complications in liver transplantation. Selective bowel decontamination increases the risk of infection and hospital stay compared to prebiotics and probiotics. The use of prebiotics and probiotics offers promise. Further randomised clinical trials are necessary.

Is phage therapy acceptable in the immunocompromised host?

Over the last decade, bacteriophages (bacterial viruses) have emerged as the major alternative to antibiotics in the treatment of antibiotic-resistant infections. While a considerable body of evidence has accumulated for the efficacy and safety of phage therapy in immunocompetent patients, data remain relatively scarce regarding its use in the immunocompromised host. To our knowledge, the present article is the first to summarize all findings, of both experimental and clinical studies, that may be relevant to the employment of phage therapy in immunocompromised patients. The available data suggest that bacteriophages could also be an efficacious and safe therapeutic modality in such patients.

Intrahepatic cholestasis after liver transplantation

Biochemical cholestasis after liver transplantation is common and often has no clinical significance if biliary anastomosis strictures and leaks have been excluded. There is no agreed upon definition for severe cholestasis, but it is associated with a worse mortality. There has been little evaluation on risk factors, but these include cryoprecipitate and platelet transfusion intraoperatively, nonidentical blood group, suboptimal graft appearance, inpatient status before transplant, and bacteremia within the first month. Associated causes considered as early (<6 months) include ischemia-reperfusion injury, primary nonfunction, small-for-size graft syndrome, infection, drugs and acute cellular rejection. Late causes include hepatic artery thrombosis, chronic rejection, biliary complications, recurrent viral and cholestatic disease, and posttransplant lymphoproliferative disorder.

Surgical site infections in liver recipients in the early posttransplantation period: etiological agents and susceptibility profiles

OBJECTIVE

This study evaluated the frequency of microbial isolates and their susceptibility profiles from cultures at the surgical site of 83 liver recipients in the early posttransplantation period.

PATIENTS AND METHODS

We prospectively collected microbiologic culture data on 83 adult patients undergoing orthotopic liver transplantation (OLT) using standard procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was performed by the Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

All patients were followed prospectively for the first 4 weeks after surgery. Among 284 microbial isolates from clinical surgical site samples in 80 liver recipients, cultures were positive in 110 samples. The most commonly isolated species were: Gram-positive cocci (n = 222 isolates, 78%) with dominance of methicillin-resistant coagulase-negative staphylococci (MRCNS; 42%) and high-level aminoglycoside-resistant enterococci (HLAR strains; 24.3%). Gram-negative bacteria were identified in 21.5% of positive cultures, including 30 strains (24%) from the Enterobacteriaceae family, with 13.3% of extended spectrum beta-lactamase producers [ESBL(+)]. Significant differences (P = .0012) were observed during the analysis of changes in the occurrence of Gram-positive bacteria isolated from the surgical site in the first week versus the second to the end of the fourth week.

CONCLUSION

Gram-positive bacteria predominated as 78% of isolates.

Incidence and Timing of Infections After Liver Transplant in Italy

BACKGROUND

Infections are one of the main complications that cause high morbidity and mortality in transplant recipients. This study sought to estimate the incidence of infections and their main determinants in liver transplant recipients in the first year after transplantation.

PATIENTS AND METHODS

A prospective study was conducted on 103 consecutive patients (72% men) who underwent transplantation in three centers in Northern (Bologna) and Central (Rome) Italy in 2005. Person-years (PY) at risk, incidence rates (IR), IR ratios and 95% confidence intervals were computed for viral, fungal, and bacterial infections.

RESULTS

The 103 patients (median age 55 years) contributed a total of 78.2 PYs, with a median follow-up of 286 days (interquartile range: 194 to 365 days). Fifty-eight patients (56.3%) experienced one or more infections, namely, 151 events (IR = 193.2 infections/100 PYs). IR for bacterial, fungal, and viral infections were 110.0, 56.3, and 26.9 infections/100 Pys, respectively. Within the first 30 days after transplantation, 37.9% patients (39/103) developed one or more events. Bacterial infections represented the most frequent event (86/151, 57.0%). Risk factors significantly associated with increased IR were gender (female), age (>50 years), prolonged intensive care stay volume of blood transfused during surgery and posttransplant, and need for retransplantation.

CONCLUSIONS

These preliminary results showed the relevance of infectious events after liver transplantation especially those of bacterial etiology, and identified factors mainly associated with their occurrence.

Infecciones en los pacientes trasplantados de hígado

Infection is the main cause of morbidity and mortality in liver transplant patients. Infections appear in three different periods following transplantation and are related to surgical factors, the degree of immunosuppression, environmental exposure and the type of prophylaxis used. Bacterial infections occur in the first two months after transplantation as bacteremia, surgical wound and intra-abdominal infection, or pneumonia. Tuberculosis in the liver transplant recipient is more aggressive than in immunocompetent persons. Viruses produce direct infection in these patients; moreover, some viruses (e.g., cytomegalovirus and human herpes virus 6) are immunomodulators and can facilitate other infections and graft rejection. Polymerase chain reaction and antigenemia techniques have made possible prompt diagnosis of cytomegalovirus infection and the implementation of prophylactic strategies. Fungal infections still have a high associated mortality rate, despite new diagnostic techniques and new antifungal drugs.

Hepatobiliary pathology

PURPOSE OF REVIEW

Recent papers on disorders of the liver and biliary tract which clarify their pathogenesis and attendant morphologic changes are highlighted.

RECENT FINDINGS

The concept of 'bystander hepatitis' was cited in studies showing hepatic infiltration of CD8-positive T cells in the setting of extrahepatic infections such as influenza virus and severe acute respiratory syndrome. Diabetic liver lesions include glycogenic hepatopathy (in which poor diabetic control leads to swollen, glycogen-filled hepatocytes without fat, steatohepatitis or fibrosis) and diabetic hepatosclerosis in which there is diffuse perisinusoidal fibrosis (type IV collagen) without zonal predilection. Ground-glass hepatocellular inclusions (positive with periodic acid-Schiff stain for glycogen) were reported in three separate series of patients who were hepatitis B virus-negative, often transplant recipients, immunosuppressed and on multiple medications. A Banff consensus paper expertly compared and contrasted the histologic features which characterize the various causes of late liver allograft dysfunction.

SUMMARY

Informative papers emerged this past year concerning collateral damage to the liver in extrahepatic infections, diabetic lesions and causes of liver dysfunction after transplantation, among other topics.

Update in infectious diseases in liver transplant recipients

The prevention and management of bacterial, fungal, and viral infections are important components in the care of the liver transplant recipient. Although much progress has been made, challenges still remain. This article provides updates on the management of bilomas and peritonitis, the prevention and management of invasive Candida and Aspergillus infections, the prevention and management of cytomegalovirus disease, and the current status of liver transplantation in HIV-infected patients.

[Intensive care treatment following transplant surgery]

Transplant-related intensive care treatment after transplantation of visceral organs, in Germany traditionally headed by transplant surgeons, is an integral part of postoperative therapy after liver, pancreas, intestinal, and combined organ transplantation, i.e. pancreas-kidney, liver-kidney, and multivisceral transplantation. Apart from adjustment and monitoring of immunosuppressive therapy, as well as common intensive care issues such as cardiopulmonary disease and complications, the avoidance, early detection, and rigorous treatment of transplant-related problems are the focus of surgical intensive care treatment of transplant patients. In the following article, its role after visceral organ transplantation is described regarding the most frequent transplant-related complications such as technical failure, various kinds of infection, and graft failure with different etiologies.