Bacterial infection after liver transplantation

Carbapenem-Resistant Klebsiella pneumoniae influences the outcome of early infections in liver transplant recipients

Background

Infections remain a leading cause of morbidity and mortality among liver transplant (LT) recipients. The aim of our study was to define the factors associated with outcome of early bacterial and fungal infections in a cohort of patients who underwent LT at the University Hospital of Ancona over a nine year period.

Methods

All consecutive patients who underwent LT in our center were considered. An early infection was defined as occurring in the first month post-transplantation.

Results

Among 330 patients who underwent LT from August 2005 to October 2014, 88 (27 %) had at least one infection documented within 30 days after transplantation. In 54 cases only one site was involved, in 34 cases ≥2 sites. There were 43 (30 %) pneumonia, 40 (27 %) surgical site infections, 31 (22 %) blood stream infections, and 30 (21 %) urinary tract infections. Gram-negative bacteria accounted for 64 % of the culture-positive cases, followed by Gram-positive bacteria (30 %) and fungi (6 %). A high proportion of drug-resistant strains was found within either Gram-negative (79 %) or Gram-positive (81 %) bacteria. There were 27 out 88 patients (31 %) who died within 180 days from the transplant. Factors independently associated with a higher risk of mortality were: renal replacement therapy (HR 11.797 [CI95 % 3.082–45.152], p < 0.0001), multisite infections (HR 4.865 [CI95 % 1.417–16.700], p = 0.012) and being infected with carbapenem-resistant Klebsiella pneumoniae (CRKP; HR 5.562 [CI95 % 1.186–26.088], p = 0.030).

Conclusions

Overall, these data indicate that early infections in LT patients are characterized by significant mortality. In particular, an early infection caused by CRKP has an adverse impact on survival in these patients suggesting an urgent need for adopting preventive measures to avoiding this complication.

Systemic hemodynamics in advanced cirrhosis: Concerns during perioperative period of liver transplantation

Advanced liver cirrhosis is usually accompanied by portal hypertension. Long-term portal hypertension results in various vascular alterations. The systemic hemodynamic state in patients with cirrhosis is termed a hyperdynamic state. This peculiar hemodynamic state is characterized by an expanded blood volume, high cardiac output, and low total peripheral resistance. Vascular alterations do not disappear even long after liver transplantation (LT), and recipients with cirrhosis exhibit a persistent systemic hyperdynamic state even after LT. Stability of optimal systemic hemodynamics is indispensable for adequate portal venous flow (PVF) and successful LT, and reliable parameters for optimal systemic hemodynamics and adequate PVF are required. Even a subtle disorder in systemic hemodynamics is precisely indicated by the balance between cardiac output and blood volume. The indocyanine green (ICG) kinetics reflect the patient’s functional hepatocytes and effective PVF, and PVF is a major determinant of the ICG elimination constant (kICG) in the well-preserved allograft. The kICG value is useful to set the optimal PVF during living-donor LT and to evaluate adequate PVF after LT. Perioperative management has a large influence on the postoperative course and outcome; therefore, key points and unexpected pitfalls for intensive management are herein summarized. Transplant physicians should fully understand the peculiar systemic hemodynamic behavior in LT recipients with cirrhosis and recognize the critical importance of PVF after LT.

Postoperative Care of a Liver Transplant Recipient Using a Classification System: Type A (Stable) Versus Type B (Unstable)

Liver transplantation has become an effective and valuable option for patients with end-stage liver disease and hepatocellular carcinoma. Liver failure, an acute or chronic condition, results in impaired bile production and excretion, clotting factor production, protein synthesis, and regulation of metabolism and glucose. Some acute conditions of liver disease have the potential to recover if the liver heals on its own. However, chronic conditions, such as cirrhosis, often lead to irreversible disease and require liver transplantation. In this publication, we review the pathophysiology of liver failure, examine common conditions that ultimately lead to liver transplantation, and discuss the postoperative management of patients who are either hemodynamically stable (type A) or unstable (type B).

Minimizing tacrolimus decreases the risk of new-onset diabetes mellitus after liver transplantation

AIM: To investigate the impact of minimum tacrolimus (TAC) on new-onset diabetes mellitus (NODM) after liver transplantation (LT).

METHODS: We retrospectively analyzed the data of 973 liver transplant recipients between March 1999 and September 2014 in West China Hospital Liver Transplantation Center. Following the exclusion of ineligible recipients, 528 recipients with a TAC-dominant regimen were included in our study. We calculated and determined the mean trough concentration of TAC (cTAC) in the year of diabetes diagnosis in NODM recipients or in the last year of the follow-up in non-NODM recipients. A cutoff of mean cTAC value for predicting NODM 6 mo after LT was identified using a receptor operating characteristic curve. TAC-related complications after LT was evaluated by χ² test, and the overall and allograft survival was evaluated using the Kaplan-Meier method. Risk factors for NODM after LT were examined by univariate and multivariate Cox regression.

RESULTS: Of the 528 transplant recipients, 131 (24.8%) developed NODM after 6 mo after LT, and the cumulative incidence of NODM progressively increased. The mean cTAC of NODM group recipients was significantly higher than that of recipients in the non-NODM group (7.66 ± 3.41 ng/mL vs 4.47 ± 2.22 ng/mL, P < 0.05). Furthermore, NODM group recipients had lower 1-, 5-, 10-year overall survival rates (86.7%, 71.3%, and 61.1% vs 94.7%, 86.1%, and 83.7%, P < 0.05) and allograft survival rates (92.8%, 84.6%, and 75.7% vs 96.1%, 91%, and 86.1%, P < 0.05) than the others. The best cutoff of mean cTAC for predicting NODM was 5.89 ng/mL after 6 mo after LT. Multivariate analysis showed that old age at the time of LT (> 50 years), hypertension pre-LT, and high mean cTAC (≥ 5.89 ng/mL) after 6 mo after LT were independent risk factors for developing NODM. Concurrently, recipients with a low cTAC (< 5.89 ng/mL) were less likely to become obese (21.3% vs 30.2%, P < 0.05) or to develop dyslipidemia (27.5% vs 44.8%, P <0.05), chronic kidney dysfunction (14.6% vs 22.7%, P < 0.05), and moderate to severe infection (24.7% vs 33.1%, P < 0.05) after LT than recipients in the high mean cTAC group. However, the two groups showed no significant difference in the incidence of acute and chronic rejection, hypertension, cardiovascular events and new-onset malignancy.

CONCLUSION: A minimal TAC regimen can decrease the risk of long-term NODM after LT. Maintaining a cTAC value below 5.89 ng/mL after LT is safe and beneficial.

Infectious Complications After Liver Transplantation

Orthotopic liver transplantation (OLT) is the standard of care for patients with decompensated cirrhosis and for patients with hepatocellular carcinoma. More than 6000 liver transplants are performed annually in the United States. High patient and graft survival rates have been achieved in great part due to the availability of potent immunosuppressive agents. Systemic immunosuppression has rendered the liver recipient susceptible to de novo infections as well as reactivation of preexisting latent infections. Infections occurring during the first month post-OLT are usually nosocomial, donor-derived, or the result of a perioperative complication. The development of opportunistic infections (OIs) such as Aspergillus and the reactivation of latent infections such as Mycobacterium tuberculosis are more frequent 1 to 6 months posttransplant, when the net state of immunosuppression is the highest. Immunosuppressive therapy is tapered 6 to 12 months post-OLT; therefore, infections occurring during that time period and afterward generally resemble those of the general population. Screening strategies applied to determine the risk of an infection after transplantation and the use of prophylactic antimicrobial therapy have reduced the incidence of OIs after OLT. This article will review the various causes of infection post-OLT and the therapies used to manage complications.

Impact of abdominal drainage systems on postoperative complication rates following liver transplantation

BACKGROUND

Depending on the extent of surgery, coagulation status and the number of anastomoses, drains are routinely used during liver transplantation. The aim of this study was to compare different drain types with regard to abdominal complication rates.

METHODS

All consecutive full-size orthotopic liver transplantations (LTX) performed over a 7-year period were included in this retrospective analysis. Abdominal drain groups were divided into open-circuit drains and closed-circuit drains. Data are reported as total number (%) or median (range); for all comparisons a p value <0.05 was considered statistically significant.

RESULTS

A total of 256 LTX [age 56.89 (0.30-75.21) years; MELD 14.5 (7-40)] was included; 56 (21.8 %) patients received an open-circuit Easy Flow Drain (Group 1) and 200 (78.2 %) a closed-circuit Robinson Drainage System (Group 2). For Groups 1 and 2, overall infection rates were 78.6 and 56 % (p = 0.001), abdominal infection rates 50.82 and 21.92 % (p = 0.001), yeast infection rates 37 and 23 % (p = 0.02), abdominal bleeding rates 26.78 and 17 % (p = 0.07), biliary complication rates 14.28 and 13.5 % (p = 0.51), respectively.

CONCLUSIONS

In this retrospective series, open-circuit drains were associated with more abdominal complications, mainly due to intraabdominal infections, than were closed-circuit drains.

Septic arthritis in immunocompetent and immunosuppressed hosts

Septic arthritis has long been considered an orthopedic emergency. Historically, Neisseria gonorrhoeae and Staphylococcus aureus have been the most common causes of septic arthritis worldwide but in the modern era of biological therapy and extensive use of prosthetic joint replacements, the spectrum of microbiological causes of septic arthritis has widened considerably. There are also new approaches to diagnosis but therapy remains a challenge, with a need for careful consideration of a combined medical and surgical approach in most cases.

Distribution and resistance of pathogens in liver transplant recipients with Acinetobacter baumannii infection

BACKGROUND

Drug-resistant Acinetobacter baumannii has become a major problem in liver transplant recipients. The aim of this study was to investigate the clinical presentation, distribution, and drug susceptibility characteristics in liver recipients with A. baumannii infection.

METHODS

We retrospectively investigated 17 liver recipients who developed A. baumannii infection between January 1, 2007 and December 31, 2014. The distribution of A. baumannii and drug susceptibility characteristics were reviewed.

RESULTS

Infectious complications due to A. baumannii appeared in 17 liver recipients, with a total of 24 episodes. Approximately 63% (15/24) of A. baumannii infections occurred within 2 weeks after transplantation. The most common source of infection was multiple culture-positive sites (35.3%, n=6), followed by the intra-abdominal/biliary tract (23.5%, n=4) and lung (23.5%, n=4). Eight patients (47.1%) had a body temperature of 38°C or higher at the onset of A. baumannii infection. Nine, seven, and 12 recipients had a serum creatinine level of >1.5 mg/dL, a white blood cell count of >15,000/mm(3), and a platelet count of <50,000/mm(3), respectively. There were five (29.4%) cases of septic shock and eight (47.1%) deaths. The rate of antibiotic resistance of A. baumannii to ten of 12 antibiotics investigated was more than 60%. Among the 24 infections caused by A. baumannii, 75% were carbapenem-resistant. The rods were relatively sensitive to tigecycline and cefoperazone-sulbactam.

CONCLUSION

The clinical manifestations of A. baumannii infection included a high body temperature, a decreased platelet count, an elevated white blood cell count, and onset in the early period after transplantation as well as high mortality. The antibiotic resistance rate of A. baumannii was extremely high. Prevention measures and combination antibiotic therapy are needed to improve the outcomes of liver recipients with A. baumannii infections.

Distribution and resistance of pathogens in liver transplant recipients with Acinetobacter baumannii infection

Background

Drug-resistant Acinetobacter baumannii has become a major problem in liver transplant recipients. The aim of this study was to investigate the clinical presentation, distribution, and drug susceptibility characteristics in liver recipients with A. baumannii infection.

Methods

We retrospectively investigated 17 liver recipients who developed A. baumannii infection between January 1, 2007 and December 31, 2014. The distribution of A. baumannii and drug susceptibility characteristics were reviewed.

Results

Infectious complications due to A. baumannii appeared in 17 liver recipients, with a total of 24 episodes. Approximately 63% (15/24) of A. baumannii infections occurred within 2 weeks after transplantation. The most common source of infection was multiple culture-positive sites (35.3%, n=6), followed by the intra-abdominal/biliary tract (23.5%, n=4) and lung (23.5%, n=4). Eight patients (47.1%) had a body temperature of 38°C or higher at the onset of A. baumannii infection. Nine, seven, and 12 recipients had a serum creatinine level of >1.5 mg/dL, a white blood cell count of >15,000/mm³, and a platelet count of <50,000/mm³, respectively. There were five (29.4%) cases of septic shock and eight (47.1%) deaths. The rate of antibiotic resistance of A. baumannii to ten of 12 antibiotics investigated was more than 60%. Among the 24 infections caused by A. baumannii, 75% were carbapenem-resistant. The rods were relatively sensitive to tigecycline and cefoperazone-sulbactam.

Conclusion

The clinical manifestations of A. baumannii infection included a high body temperature, a decreased platelet count, an elevated white blood cell count, and onset in the early period after transplantation as well as high mortality. The antibiotic resistance rate of A. baumannii was extremely high. Prevention measures and combination antibiotic therapy are needed to improve the outcomes of liver recipients with A. baumannii infections.

Chronic alcohol consumption potentiates the development of diabetes through pancreatic β-cell dysfunction

Chronic ethanol consumption is well established as a major risk factor for type-2 diabetes (T2D), which is evidenced by impaired glucose metabolism and insulin resistance. However, the relationships between alcohol consumption and the development of T2D remain controversial. In particular, the direct effects of ethanol consumption on proliferation of pancreatic β-cell and the exact mechanisms associated with ethanol-mediated β-cell dysfunction and apoptosis remain elusive. Although alcoholism and alcohol consumption are prevalent and represent crucial public health problems worldwide, many people believe that low-to-moderate ethanol consumption may protect against T2D and cardiovascular diseases. However, the J- or U-shaped curves obtained from cross-sectional and large prospective studies have not fully explained the relationship between alcohol consumption and T2D. This review provides evidence for the harmful effects of chronic ethanol consumption on the progressive development of T2D, particularly with respect to pancreatic β-cell mass and function in association with insulin synthesis and secretion. This review also discusses a conceptual framework for how ethanol-produced peroxynitrite contributes to pancreatic β-cell dysfunction and metabolic syndrome.

Predictive factors of neurological complications and one-month mortality after liver transplantation

Background: Neurological complications are common after orthotopic liver transplantation (OLT). We aimed to characterize the risk factors associated with neurological complications and mortality among patients who underwent OLT in the post-model for end-stage liver disease (MELD) era.

Methods: In a retrospective review, we evaluated 227 consecutive patients at the Keck Hospital of the University of Southern California before and after OLT to define the type and frequency of and risk factors for neurological complications and mortality.

Results: Neurological complications were common (n = 98), with encephalopathy being most frequent (56.8%), followed by tremor (26.5%), hallucinations (11.2%), and seizure (8.2%). Factors associated with neurological complications after OLT included preoperative dialysis, hepatorenal syndrome, renal insufficiency, intra-operative dialysis, preoperative encephalopathy, preoperative mechanical ventilation, and infection. Preoperative infection was an independent predictor of neurological complications (OR 2.83, 1.47–5.44). One-month mortality was 8.8% and was independently associated with urgent re-transplant, preoperative intubation, and intra-operative arrhythmia.

Conclusion: Neurological complications are common in patients undergoing OLT in the post-MELD era, with encephalopathy being most frequent. An improved understanding of the risk factors related to both neurological complications and one-month mortality post-transplantation can better guide perioperative care and help improve outcomes among OLT patients.