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

Imaging Characteristics of Invasive Pulmonary Fungal Infection Secondary to Hematological Diseases and Comparison before and after Treatment

Fungal infections have become crucial factors that threaten the prognosis and survival of blood disease patients. Here, we aim to analyze the epidemiological characteristics and early and advanced CT (computed tomography) manifestations of patients with invasive pulmonary fungal infections secondary to blood system diseases. 65 hospitalized patients from October 2018 to October 2020 with invasive pulmonary fungal infections secondary to blood diseases were enrolled. Blood diseases were recorded according to clinical and imaging data, and the serum galactomannan test (GM test) was conducted. Two senior radiologists analyzed the CT data and recorded the distribution of the lesions and CT signs. We analyzed and counted the first chest CT scan images of patients with nodule/mass type secondary to hematological diseases and invasive pulmonary fungal infection. The first CT nodules or mass-type lesions were statistically significant in nodule size, the number of lesions, distribution, and accompanying signs. Pulmonary fungal infection was common in both lungs during 7-day, 14-day, and 30-day follow-up CT. We also found that the nodular mass type was the main manifestation in the positive group of the GM test. Both the positive group and the negative group had the highest incidence of nodules. The incidence of air crescent signs in nodules or mass lesions in the positive group was higher than in the negative group, and the difference was statistically significant. To conclude, follow-up CT signs after antifungal treatment were highly sensitive to the early diagnosis of hematological diseases and secondary invasive pulmonary Eumycetes infection, which could be used for clinical treatment to provide help. GM test results were also related to CT manifestations such as air crescent sign, cavity, and halo sign.

Effects of Gut Metabolites and Microbiota in Healthy and Marginal Livers Submitted to Surgery

Microbiota is defined as the collection of microorganisms within the gastrointestinal ecosystem. These microbes are strongly implicated in the stimulation of immune responses. An unbalanced microbiota, termed dysbiosis, is related to the development of several liver diseases. The bidirectional relationship between the gut, its microbiota and the liver is referred to as the gut–liver axis. The translocation of bacterial products from the intestine to the liver induces inflammation in different cell types such as Kupffer cells, and a fibrotic response in hepatic stellate cells, resulting in deleterious effects on hepatocytes. Moreover, ischemia-reperfusion injury, a consequence of liver surgery, alters the microbiota profile, affecting inflammation, the immune response and even liver regeneration. Microbiota also seems to play an important role in post-operative outcomes (i.e., liver transplantation or liver resection). Nonetheless, studies to determine changes in the gut microbial populations produced during and after surgery, and affecting liver function and regeneration are scarce. In the present review we analyze and discuss the preclinical and clinical studies reported in the literature focused on the evaluation of alterations in microbiota and its products as well as their effects on post-operative outcomes in hepatic surgery.

Biofilm formation by multidrug resistant Enterobacteriaceae strains isolated from solid organ transplant recipients

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant bacteria (MDR). In this study, the biofilm-forming capability of 209 MDR strains (Escherichia coli n = 106, Klebsiella pneumoniae n = 78, and Enterobacter spp. n = 25) isolated from rectal swabs in the first 48 hours before or after kidney (93 patients), liver (60 patients) or kidney/pancreas transplants (5 patients) were evaluated by using a microplate assay. Thirty-nine strains were isolated before transplant and 170 strains were isolated post-transplant. Overall, 16% of E. coli strains, 73% of K. pneumoniae strains and 4% Enterobacter strains showed moderate or strong biofilm production. Nine strains isolated from infection sites after transplantation were responsible of infections in the first month. Of these, 4 K. pneumoniae, 1 E. coli and 1 Enterobacter spp. strains isolated pre-transplant or post-transplant as colonizers caused infections in the post-transplant period. Our results suggest that in vitro biofilm formation could be an important factor for adhesion to intestine and colonization in MDR K. pneumoniae strains in SOT recipients, but this factor appears to be less important for MDR E. coli and Enterobacter spp.

Influence of gut microbiota and intestinal barrier on enterogenic infection after liver transplantation

Liver transplantation is currently a standard therapy for patients with end-stage liver diseases and hepatocellular carcinoma. Given that liver transplantation has undergone a thriving development in these decades, the survival rates after liver transplantation have markedly improved as a result of the critical advancement in surgical techniques, immunosuppressive therapies, and post-operative care. However, infection remains a fatal complication after liver transplantation surgery. In particular, enterogenic infection represents a major complication in liver transplant recipients. This article gives an overview of infection cases after liver transplantation and focuses on the discussion of enterogenic infection in terms of its pathophysiology, risk factor, outcome, and treatment.

Epidemiological Analysis of Extended-Spectrum Beta-Lactamase-Producing Bacterial Infections in Adult Live Donor Liver Transplant Patients

Introduction:

Bacterial infections are a leading cause of morbidity and mortality in patients receiving solid-organ transplants. Extended-spectrum beta-lactamases (ESBL) pathogens are the most important pathogenic bacteria infecting these patients.

Aim:

This study aims to evaluate for the incidence and characteristics of ESBL-positive organism, to look for the clinical outcomes in ESBL-positive infected cases, and to evaluate and draft the antibiotic policy in posttransplant patients during the first 28 days posttransplant.

Materials and Methods:

This is a retrospective data analysis of liver transplant recipients infected with ESBL culture-positive infections. All the culture sites such as blood, urine, and endotracheal tube aspirates were screened for the first ESBL infection they had and noted. This data were collected till day 28 posttransplant. The antibiotic susceptibility pattern and the most common organism were also noted.

Results:

A total of 484 patients was screened and 116 patients had ESBL-positive cultures. Out of these, 54 patients had infections and 62 patients were ESBL colonizers. The primary infection site was abdominal fluid (40.7%), with Klebsiella accounting for most of the ESBL infections. Colistin was the most sensitive antibiotic followed by tigecycline. The overall mortality was 11.4% and 31 out of 54 ESBL-infected patients died.

Conclusions:

Infections with ESBL-producing organism in liver transplant recipients has a high mortality and very limited therapeutic options.

C7 genotype of the donor may predict early bacterial infection after liver transplantation

Post-transplantation infection causes high mortality and remains a significant challenge. High clinical risk factors for bacterial infection in recipients are often found in critically ill patients. However, for some recipients, bacterial infections are inevitable. It is conceivable that this susceptibility may be related to the genetics of the donor and recipient. Using expression quantitative trait loci (eQTL) analysis, we found that the C7 rs6876739 CC genotypes and mannan-binding lectin (MBL2) gene polymorphisms of liver donors were significantly associated with bacterial infection in recipients. In an extended validation group of 113 patients, donor C7 rs6876739 genetic variation was an independent risk factor for bacterial infection. The donor C7 rs6876739 CC genotype was associated with lower levels of recipient C7 protein, soluble membrane attack complex (MAC), and IL-1β expression compared with the donor C7 rs6876739 TT genotype. In vitro, the MAC significantly triggered NLRP3 inflammasome activation and IL-1β release, suggesting that the mechanism by which C7 defends against bacteria may involve MAC formation, leading to NLRP3 inflammasome activation and IL-1β release. Our findings may be helpful in identifying transplantation recipients at risk of bacterial infection prior to surgery and may contribute to novel infection prevention strategies and the improvement of postoperative outcomes.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical site infection in liver transplant recipients: impact of the type of perioperative prophylaxis

Surgical site infection (SSI) is an important cause of morbidity after orthotopic liver transplantation (OLT). Perioperative antibiotic prophylaxis is one of the main modifiable risk factors. We prospectively investigated the epidemiology, risk factors, and prognosis of SSI in a cohort of 167 OLT. Two different schedules of antibiotic SSI prophylaxis were compared. Fifty-six episodes of SSI were included (0.34 episodes/patient). The SSI incidence among patients who received cefazolin and amoxicillin-clavulanate did not differ. Bacteria caused all episodes. The most common pathogen was Escherichia coli (21.25%), among which 47% were extended-spectrum beta-lactamase producers. The only risk factor for SSI was antibiotic therapy before OLT. Patients with SSI had a longer hospital and intensive care unit stay (P<0.05), but survival did not differ. In conclusion, SSI has a high incidence despite antibiotic perioperative prophylaxis; therefore, an integral perspective of SSI and a multifactorial approach other than antimicrobial prophylaxis are needed to prevent it.

Effect of antibiotic prophylaxis on the risk of surgical site infection in orthotopic liver transplant

Surgical site infections are common bacterial infections in orthotopic liver transplantation. The purpose of this study was to determine the incidence, timing, location, and risk factors, specifically antibiotic prophylaxis, for surgical site infections. A prospective study was performed that included a population of 1222 consecutive patients (73.0% males) who underwent liver transplantation in Spanish hospitals belonging to the Red de Estudio de la Infección en el Trasplante research network. One hundred seven patients developed surgical site infections. The predominant infection sites were incisional wound (53 episodes) and peritonitis (40 episodes). The timing of the organ/space surgical site infections was slightly delayed in comparison with incisional surgical site infections. Enterococcus spp., Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii were the predominant pathogens. Choledochojejunal or hepaticojejunal reconstruction (odds ratio, 4.2; 95% confidence interval, 1.6-10.7), previous liver or kidney transplant (odds ratio, 2.6; 95% confidence interval, 1.1-6.3), and more than 4 red blood cell units transfused (odds ratio, 2.0; 95% confidence interval, 1.1-3.4) were independently associated with the development of surgical site infections. Biliary reconstruction by choledochojejunostomy or hepaticojejunostomy increases the risk of surgical site infections.

Impact of surveillance stool culture guided selection of antibiotics in the management of pediatric small bowel transplant recipients

Surveillance stool cultures (SSC) have been used in immunocompromised populations to predict the organisms associated with invasive infections and aid in the selection of empiric antibiotic regimens. To evaluate the utility of this approach in pediatric small bowel transplant (SBT) recipients, we conducted a retrospective review of 33 patients who underwent SBT, 16 of whom had SSC done. In no case was the same organism isolated from SSC and subsequent blood, peritoneal fluid or wound cultures. In the first month post-transplantation, blood cultures were positive in 44% and 35% of patients that had and did not have SSC done, respectively (p = 0.73); peritoneal fluid cultures in 44% and 65% (p = 0.30); and wound cultures in 44% and 24% (p = 0.28). There were no significant differences among both groups in time to first infection, duration of ICU stay following SBT, graft survival or long-term patient survival. We conclude that SSC-guided antibiotic selection does not have a significant impact on the incidence of invasive infections in the first month following SBT or on specific indicators of patient outcome. This suggests that empiric antibiotic regimens should be selected based on clinical presentation and hospital flora and susceptibility patterns.

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

INTRODUCTION

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

METHODS

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

RESULTS

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