Bloodstream infections among solid organ transplant recipients: epidemiology, microbiology, associated risk factors for morbility and mortality

Analyzing the Donor Dilemma: Outcomes of Kidney Transplant Recipients From Donors With Positive Blood Cultures Obtained at Organ Procurement

Based on expert consensus, the American Society of Transplantation recommends 7-14 days of preventive antibiotic therapy for solid organ transplant recipients from donors with positive blood cultures. We evaluated management and outcomes of kidney transplant recipients from these donors.

Is intestinal colonization with multidrug-resistant Enterobacterales associated with higher rates of nosocomial Enterobacterales bloodstream infections?

OBJECTIVES

Intestinal colonization with multidrug-resistant Enterobacterales (MDRE-IC) increases the risk of MDRE bloodstream infection (BSI). However, its impact on the overall risk of nosocomial Enterobacterales bloodstream infections (nE-BSIs) remains unclear. This study aimed to determine this risk and identify associated factors in hospitalized patients.

DESIGN

This retrospective cohort study at a 3200-bed tertiary institution including patients hospitalized in 2019 who underwent MDRE rectal swab (RS) screening. Inclusion criteria were age ≥18 years, first RS in 2019, follow-up ≥7 days, and Enterobacterales BSIs >48 hours after RS. The primary outcome was the first nE-BSI during the follow-up period, analyzed using a Cox model.

RESULTS

Among 7006 patients, 817 (11.9%) had MDRE-IC. Most were male and primarily hospitalized in acute wards. nE-BSIs occurred in 433 (6.1%) patients and were more frequent in patients with MDRE-IC than the non-colonized group (adjusted hazard ratio [aHR] = 1.78, 95% confidence interval [CI]: 1.40-2.26). Intestinal colonization with extended-spectrum β-lactamase-producing and carbapenemase-resistant Enterobacterales showed similar risks for Enterobacterales BSI onset: aHR = 1.73 (95% CI: 1.33-2.24) and aHR = 2.02 (95% CI: 1.27-3.22), respectively.

CONCLUSIONS

In hospitalized patients, MDRE-IC is associated with a higher rate of nE-BSI than those without MDRE-IC, underscoring the urgent need for improved infection prevention and control measures, as well as optimized antibiotic use to mitigate this risk.

Clinical response to nonsurgical periodontal therapy is associated with decreased serum leukocyte count and uric acid levels in kidney transplant recipients

OBJECTIVE

This study sought to investigate the relationship between clinical response to nonsurgical periodontal therapy (NSPT) and serum changes in leukocyte count, fasting blood glucose, hemoglobin, hematocrit, creatinine, and uric acid in kidney transplant recipients (KTR).

METHODOLOGY

A prospective study was performed on 20 KTRs. Periodontal and serum data were collected before and 90 days after NSPT, and delta values (Δ = after NSPT - before) were calculated. Periodontal assessment included periodontal probing depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP). Patients were classified based on the presence of periodontitis and then categorized into stages.

RESULTS

Patients showed a reduction in the percentage of sites with PPD≥3mm, PPD≥4 mm and BOP, after NSPT. There was a direct correlation between the deltas of leukocyte count and CAL ≥3 mm (r=0.645, P=0.002) and BOP (r=0.663, P=0.001), and the deltas of uric acid and CAL ≥3 mm (r=0.562, P=0.010).

CONCLUSION

A good clinical response to NSPT may affect the reduction of serum levels of leukocyte count and uric acid, suggesting a beneficial effect on systemic health in KTR.

Can the pan-immune-inflammation value predict gram negative bloodstream infection-related 30-day mortality in solid organ transplant patients?

BACKGROUND

The recently used pan-immune-inflammation value (PIV) has not been adequately studied as a predictive marker for mortality in immunosuppressed patients. The aim of this study was to evaluate the usefulness of baseline PIV level as a predictor of 30-day mortality in solid organ transplant (SOT) recipients with gram negative bloodstream infections (GN-BSI).

METHODS

This retrospective, cross-sectional study was conducted between January 1, 2019, and December 31, 2022, in 1104 SOT recipients. During the study period, 118 GN-BSI were recorded in 113 patients. Clinical, epidemiological, and laboratory data were collected, and mortality rates (30-day and all-cause) were recorded.

RESULTS

The 113 recipients had a median age of 50 years [interquartile range (IQR) 37.5-61.5 years] with a male predominance (n = 72, 63.7%). The three most common microorganisms were as follows: 46 isolates (38.9%) of Escherichia coli, 41 (34.7%) of Klebsiella pneumoniae, and 12 (10.2%) of Acinetobacter baumannii. In 44.9% and 35.6% of the isolates, production of extended-spectrum beta-lactamases and carbapenem resistance were detected, respectively. The incidence of carbapenem-resistant GN-BSI was higher in liver recipients than in renal recipients (n = 27, 69.2% vs n = 13, 17.6%, p < 0.001). All-cause and 30-day mortality rates after GN-BSI were 26.5% (n = 30), and 16.8% (n = 19), respectively. In the group with GN-BSI-related 30-day mortality, the median PIV level was significantly lower (327.3, IQR 64.8-795.4 vs. 1049.6, IQR 338.6-2177.1; p = 0.002). The binary logistic regression analysis identified low PIV level [hazard ratio (HR) = 0.93, 95% confidence interval (CI) 0.86-0.99; p = 0.04], and increased age (HR = 1.05, 95% CI 1.01-1.09; p = 0.002) as factors associated with 30-day mortality. The receiver operating characteristic analysis revealed that PIV could determine the GN-BSI-related 30-day mortality with area under curve (AUC): 0.723, 95% CI 0.597-0.848, p = 0.0005.

CONCLUSIONS

PIV is a simple and inexpensive biomarker that can be used to estimate mortality in immunosuppressed patients, but the results need to be interpreted carefully.

Pathophysiological Responses to Bloodstream Infection in Critically Ill Transplant Recipients Compared With Non-Transplant Recipients

BACKGROUND

Identification of bloodstream infection (BSI) in transplant recipients may be difficult due to immunosuppression. Accordingly, we aimed to compare responses to BSI in critically ill transplant and non-transplant recipients and to modify systemic inflammatory response syndrome (SIRS) criteria for transplant recipients.

METHODS

We analyzed univariate risks and developed multivariable models of BSI with 27 clinical variables from adult intensive care unit (ICU) patients at the University of Virginia (UVA) and at the University of Pittsburgh (Pitt). We used Bayesian inference to adjust SIRS criteria for transplant recipients.

RESULTS

We analyzed 38.7 million hourly measurements from 41 725 patients at UVA, including 1897 transplant recipients with 193 episodes of BSI and 53 608 patients at Pitt, including 1614 transplant recipients with 768 episodes of BSI. The univariate responses to BSI were comparable in transplant and non-transplant recipients. The area under the receiver operating characteristic curve (AUC) was 0.82 (95% confidence interval [CI], .80-.83) for the model using all UVA patient data and 0.80 (95% CI, .76-.83) when using only transplant recipient data. The UVA all-patient model had an AUC of 0.77 (95% CI, .76-.79) in non-transplant recipients and 0.75 (95% CI, .71-.79) in transplant recipients at Pitt. The relative importance of the 27 predictors was similar in transplant and non-transplant models. An upper temperature of 37.5°C in SIRS criteria improved reclassification performance in transplant recipients.

CONCLUSIONS

Critically ill transplant and non-transplant recipients had similar responses to BSI. An upper temperature of 37.5°C in SIRS criteria improved BSI screening in transplant recipients.

Postoperative infectious complications are associated with diminished overall survival of patients undergoing resection for colorectal liver metastases

INTRODUCTION

Postoperative infectious complications (PIC) remain one of the most common complications after surgery. The influence of PIC on long-term survival for patients after liver surgery for colorectal liver metastases (CRLM) needs further investigation.

METHODS

Data of patients who underwent liver resection for CRLM between 2012 and 2017 at the Department of Surgery, Campus Charité Mitte and Campus Virchow-Klinikum, Charité - Universitätsmedizin Berlin were evaluated. Overall survival (OS) was stratified according to the development of PIC. Independent predictors of PIC and diminished survival were identified using regression models.

RESULTS

Of 270 patients, eighty-four (31%) patients developed PIC including intraabdominal infections (n = 51, 61%), cholangitis (n = 5, 6%), pneumonia (n = 12, 14%), wound infections (n = 28, 33%), urinary tract infections (n = 5, 6%), or central line-associated bloodstream infections (n = 4, 5%). PIC were associated with a significantly diminished five-year OS (30% vs. 43%, p = 0.008). Age >65 years (p = 0.016, hazard ratio [HR] = 2.2, 95% confidence interval [CI] = 1.2-4.0), comorbidity (p = 0.019, HR [95% CI] = 2.4 [1.2-4.9]), simultaneous resection of primary tumor (p = 0.005, HR [95% CI] = 4.3 [1.6-11.9]), biliary drainage (p < 0.001, HR [95% CI] = 4.1 [2.0-8.5]), and length of procedure ≥272 min (p = 0.012, HR [95% CI] = 2.2 [1.2-4.1]) were independent predictors for the development of PIC. Body-mass index (BMI) > 30 kg/m2 (p = 0.002, HR [95% CI] = 2.4 [1.4-4.0]), postoperative major complications (p = 0.003, HR [95% CI] = 2.2 [1.3-3.8]), and 3- or 4-MRGN bacteria (p = 0.001, HR [95% CI] = 7.7 [2.2-27.3]) were independently associated with diminished OS.

CONCLUSIONS

PIC are associated with diminished OS after resection for CRLM. Age >65 years, comorbidities, simultaneous resection of the primary tumor, and biliary drainages were identified as independent risk factors for the development of PIC. High BMI, postoperative major morbidity and 3-/4-MRGN bacteria were independently predictive of worse OS. These factors need to be considered in perioperative management for patients with CRLM.

Bacteremia During the First Year After Solid Organ Transplantation: An Epidemiological Update

Background

There are limited contemporary data on the epidemiology and outcomes of bacteremia in solid organ transplant recipients (SOTr).

Methods

Using the Swiss Transplant Cohort Study registry from 2008 to 2019, we performed a retrospective nested multicenter cohort study to describe the epidemiology of bacteremia in SOTr during the first year post-transplant.

Results

Of 4383 patients, 415 (9.5%) with 557 cases of bacteremia due to 627 pathogens were identified. One-year incidence was 9.5%, 12.8%, 11.4%, 9.8%, 8.3%, and 5.9% for all, heart, liver, lung, kidney, and kidney-pancreas SOTr, respectively (P = .003). Incidence decreased during the study period (hazard ratio, 0.66; P < .001). One-year incidence due to gram-negative bacilli (GNB), gram-positive cocci (GPC), and gram-positive bacilli (GPB) was 5.62%, 2.81%, and 0.23%, respectively. Seven (of 28, 25%) Staphylococcus aureus isolates were methicillin-resistant, 2/67 (3%) enterococci were vancomycin-resistant, and 32/250 (12.8%) GNB produced extended-spectrum beta-lactamases. Risk factors for bacteremia within 1 year post-transplant included age, diabetes, cardiopulmonary diseases, surgical/medical post-transplant complications, rejection, and fungal infections. Predictors for bacteremia during the first 30 days post-transplant included surgical post-transplant complications, rejection, deceased donor, and liver and lung transplantation. Transplantation in 2014-2019, CMV donor-negative/recipient-negative serology, and cotrimoxazole Pneumocystis prophylaxis were protective against bacteremia. Thirty-day mortality in SOTr with bacteremia was 3% and did not differ by SOT type.

Conclusions

Almost 1/10 SOTr may develop bacteremia during the first year post-transplant associated with low mortality. Lower bacteremia rates have been observed since 2014 and in patients receiving cotrimoxazole prophylaxis. Variabilities in incidence, timing, and pathogen of bacteremia across different SOT types may be used to tailor prophylactic and clinical approaches.

Gram-negative bacteremia in solid organ transplant recipients: Clinical characteristics and outcomes as compared to immunocompetent non-transplant recipients

BACKGROUND

Outcomes from Gram-negative bacteremia (GNB) in solid organ transplant (SOT) recipients are poorly understood.

METHODS

This is a single center prospective cohort study comparing the clinical characteristics and outcomes of SOT recipients with GNB to immunocompetent non-SOT patients with GNB between 1/1/2002 through 12/31/2018. Outcomes of interest included incidence of septic shock, respiratory failure, and time to death. A multivariable logistic regression model was used to determine factors associated with incidence of septic shock and respiratory failure. Time to death was evaluated using Cox proportional hazard models.

RESULTS

A total of 297 SOT and 1245 immunocompetent non-SOT patients were included. Incidence of septic shock did not significantly differ between the groups (SOT 25.3% vs. non-SOT 24.6%, p = .8225). Overall survival did not significantly differ by transplant status (30-day survival: SOT 76%, 95% confidence interval [CI] 70, 92, non-SOT 74%, 95% CI 71, 77: log rank: p = .76). SOT recipients taking three immunosuppressive medications had significantly lower odds of developing septic shock or respiratory failure requiring intubation and mechanical ventilation than those taking ≤1 agent (shock: adjusted odds ratio [aOR] 0.29, 95% CI 0.09, 0.90, p = .0316; respiratory failure: aOR 0.14, 95% CI: 0.04, 0.49, p = .0020).

CONCLUSIONS

SOT recipients with GNB do not experience higher rates of septic shock, respiratory failure, or mortality than immnon-SOT recipients with GNB. Among SOT recipients, a greater number of immunosuppressive medications may be associated with improved outcomes during GNB. Future studies are needed to understand the potential relationship between levels of immunosuppression and clinical outcome in SOT recipients with GNB.

The long-term impact of bloodstream infections on patient and graft survival following kidney transplantation

BACKGROUND

There are limited data on the impact of bloodstream infections (BSI) following kidney transplantation (KT) on long term patient outcome.

METHODS

This was a retrospective parallel-cohort study. We included 123 consecutive KT recipients who were admitted with a first episode of BSI between 1/2007-12/2016. They were matched with 225 KT recipients who did not have BSI. Multivariate regression analysis with BSI as time-dependent covariate was used for the effect of BSI on graft loss, all-cause mortality and long-term graft function (defined by the slope of mean serum creatinine level).

RESULTS

During a median follow-up of 89.4 months, post-transplant BSI was independently associated with all-cause mortality (HR 5.56, 95% CI 3.07-10.09, p<0.0001) and graft failure (HR-2.82, 95% CI 1.40-5.64, p = 0.003) after adjustment for potential confounders. This association remained irrespective of the source of infection or pathogen, but became non-significant when appropriate antibiotic therapy was administrated. Baseline kidney function was independently associated with graft failure. Recipients with BSI had lower baseline kidney function, however the BSI episode had no influence on the slope of change in serum creatinine over time.

CONCLUSION

BSI after KT was associated with long-term adverse outcome. This effect was mitigated by the early administration of appropriate antibiotics. This article is protected by copyright. All rights reserved.

Assessment of pathogens and risk factors associated with bloodstream infection in the year after pediatric liver transplantation

BACKGROUND

Bloodstream infection (BSI) is one of the most significantly adverse events that can occur after liver transplantation (LT) in children.

AIM

To analyze the profile of BSI according to the postoperative periods and assess the risk factors after pediatric LT.

METHODS

Clinical data, collected from medical charts of children (n = 378) who underwent primary LT, were retrospectively reviewed. The primary outcome considered was BSI in the first year after LT. Univariate and multivariate analyses were performed to identify risk factors for BSI and respective odds ratios (ORs).

RESULTS

Of the examined patients, 106 (28%) experienced 162 episodes of pathogen-confirmed BSI during the first year after LT. There were 1.53 ± 0.95 episodes per children (mean ± SD) among BSI-complicated patients with a median onset of 0.4 mo post-LT. The most common pathogenic organisms identified were Coagulase-negative staphylococci, followed by Enterococcus spp. and Streptococcus spp. About half (53%) of the BSIs were of unknown origin. Multivariate analysis demonstrated that young age (≤ 1.3 year; OR = 2.1, P = 0.011), growth failure (OR = 2.1, P = 0.045), liver support system (OR = 4.2, P = 0.008), and hospital stay of > 44 d (OR = 2.3, P = 0.002) were independently associated with BSI in the year after LT.

CONCLUSION

BSI was frequently observed in patients after pediatric LT, affecting survival outcomes. The profile of BSI may inform clinical treatment and management in high-risk children after LT.

Bacterial and fungal bloodstream infections in solid organ transplant recipients: results from a Danish cohort with nationwide follow-up

OBJECTIVES

Bloodstream infections (BSI) are prevalent after solid organ transplantation (SOT). In this study, we aimed to investigate the incidence and risk factors for BSI in the first 5 years post-transplantation.

METHODS

The study included 1322 SOT (kidney, liver, lung and heart) recipients transplanted from 2010 to 2017 with a total of 5616 years of follow-up. Clinical characteristics and microbiology were obtained from the Centre of Excellence for Personalized Medicine of Infectious Complications in Immune Deficiency (PERSIMUNE) data repository with nationwide follow-up. Incidence was investigated in the different SOT groups. Risk factors associated with BSI were assed in the combined group in time-updated multivariable Cox regressions.

RESULTS

The cumulative incidence of first BSI in the first 5 years post-transplantation differed in the SOT groups with a lower incidence in heart transplant recipients than in the other SOT groups (heart: 4.4%, CI 0.0-9.7%, vs. kidney: 24.6%, CI 20.9-28.2%, liver: 24.7%, CI 19.4-29.9%, and lung: 19.6%, CI 14.5-24.8%, p <0.001). Age above 55 years (HR 1.71, CI 1.2-2.4, p=0.002) and higher Charlson comorbidity index score (HR per unit increase: 1.25, CI 1.1-1.4, p<0.001) at transplantation, current cytomegalovirus (CMV) infection (HR 4.5, CI 2.6-7.9, p<0.001) and current leucopenia (HR 13.3, CI 3.7-47.9, p<0.001) were all associated with an increased risk of BSI.

CONCLUSION

In SOT recipients, the incidence of BSI differed with the type of transplanted organ. Risk of BSI was higher in older recipients and in recipients with comorbidity, current CMV infection or leucopenia. Thus, increased attention towards BSI in recipients with these characteristics is warranted.

Bloodstream infections among intestinal and multivisceral transplant recipients

OBJECTIVE

To examine the etiologies, risk factors, and microbiology of bloodstream infections (BSIs) among intestinal and multivisceral transplant recipients in the 2-year post-operative period.

METHODS

A retrospective medical record review of adult intestinal or multivisceral transplant recipients between 2003 and 2015. Descriptive statistics were used to describe cohort data. Logistic regression was used to assess factors related to BSIs using a backward selection process.

RESULTS

One-hundred and six intestinal or multivisceral transplants were performed in 103 individuals. Fifty-eight percent (n = 62) developed a BSI in the 2-year post-operative period with a median time to first BSI of 53 days (interquartile range [IQR] 15, 169). The majority of BSIs were catheter related 38% (n = 58) when the source was known. Common microbiological isolates included enterococcus 20% (n = 36/174), coagulase-negative staphylococcus 14% (n = 23), and 12% Klebsiella spp (n = 21). Forty-seven percent (n = 17) of the enterococci were resistant to vancomycin, and 14% (n = 10/70) of the gram negatives were extended spectrum beta-lactamase (ESBL) producers. In adjusted analyses, (OR: 0.200 95% CI: 0.2, 0.514, P = .009) men were less likely to have a BSI. Transplant recipient age, allograft type, comorbidities, rejection, and length of stay were not noted to be risk factors for development of BSIs in our cohort. Mortality at 2-years post-transplant was similar for those who did not develop a BSI and those that developed infection, P = .5028.

CONCLUSIONS

BSIs are a common complication of intestinal transplantation, and central venous catheters were a common source. Interventions such as early catheter removal should be implemented to prevent infections in this population. Female sex association with BSI requires further investigation.

Efficacy of β-lactam/β-lactamase inhibitors to treat extended-spectrum beta-lactamase-producing Enterobacterales bacteremia secondary to urinary tract infection in kidney transplant recipients (INCREMENT-SOT Project)

BACKGROUND

Whether active therapy with β-lactam/β-lactamase inhibitors (BLBLI) is as affective as carbapenems for extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) bloodstream infection (BSI) secondary to urinary tract infection (UTI) in kidney transplant recipients (KTRs) remains unclear.

METHODS

We retrospectively evaluated 306 KTR admitted to 30 centers from January 2014 to October 2016. Therapeutic failure (lack of cure or clinical improvement and/or death from any cause) at days 7 and 30 from ESBL-E BSI onset was the primary and secondary study outcomes, respectively.

RESULTS

Therapeutic failure at days 7 and 30 occurred in 8.2% (25/306) and 13.4% (41/306) of patients. Hospital-acquired BSI (adjusted OR [aOR]: 4.10; 95% confidence interval [CI]: 1.50-11.20) and Pitt score (aOR: 1.47; 95% CI: 1.21-1.77) were independently associated with therapeutic failure at day 7. Age-adjusted Charlson Index (aOR: 1.25; 95% CI: 1.05-1.48), Pitt score (aOR: 1.72; 95% CI: 1.35-2.17), and lymphocyte count ≤500 cells/μL at presentation (aOR: 3.16; 95% CI: 1.42-7.06) predicted therapeutic failure at day 30. Carbapenem monotherapy (68.6%, primarily meropenem) was the most frequent active therapy, followed by BLBLI monotherapy (10.8%, mostly piperacillin-tazobactam). Propensity score (PS)-adjusted models revealed no significant impact of the choice of active therapy (carbapenem-containing vs any other regimen, BLBLI- vs carbapenem-based monotherapy) within the first 72 hours on any of the study outcomes.

CONCLUSIONS

Our data suggest that active therapy based on BLBLI may be as effective as carbapenem-containing regimens for ESBL-E BSI secondary to UTI in the specific population of KTR. Potential residual confounding and unpowered sample size cannot be excluded (ClinicalTrials.gov identifier: NCT02852902).

Predictors of Mortality During Initial Liver Transplant Hospitalization and Investigation of Causes of Death

BACKGROUND Liver transplant (LT) remains a life-saving procedure with a high mortality rate. The present study investigated the causes of death and sought to identify predictive factors of mortality during the initial LT hospitalization. MATERIAL AND METHODS We retrieved data on first-time adult recipients who underwent LT between November 2017 and October 2019 receiving grafts from donation after citizen's death. The risk factors for mortality during the initial LT hospitalization were confirmed by univariate analysis. We also analyzed the causes of death. RESULTS We enrolled 103 recipients, including 86 males and 17 females, with a mean age of 47.7 years. Thirty-eight (36.9%) recipients were labeled as non-cholestatic cirrhosis-related indications. Approximately 8% of all recipients had diabetes prior to LT. Induction therapy was used in 11 (10.7%) recipients, along with maintenance therapy. The median model for end-stage liver disease score at LT was 32.4 (21.4-38.4). The in-hospital mortality rate of LT recipients was 6.8% (7/103), and infections were responsible for most of the deaths (6/7). The 1 remaining death resulted from primary graft failure. Univariate analysis showed recipients with postoperative pneumonia (p2 mg/dL, and alanine transaminase on day 1 after LT >1800 µmol/L (all P<0.001) were much more likely to die. CONCLUSIONS In-hospital mortality of LT recipients was high, due in large part to infections. Acute hepatic necrosis, prolonged post-transplant ICU stays, certain types of postoperative infections, and postoperative liver and kidney dysfunction were potential risk factors for in-hospital mortality of LT recipients.

Risk Factors for Acquisition of Carbapenem-Resistant Klebsiella pneumoniae and Mortality Among Abdominal Solid Organ Transplant Recipients with K. pneumoniae Infections

BACKGROUND For abdominal solid organ transplant (ASOT) recipients, infection with Klebsiella pneumoniae, particularly carbapenem-resistant K. pneumoniae (CRKP), can be life-threatening. The aims of this study were to characterize the risk factors associated with acquisition of CRKP and 90-day crude mortality among patients. MATERIAL AND METHODS In our cohort study, we retrospectively reviewed 68 K. pneumoniae-infected transplant recipients, studied their demographics, clinical manifestations, microbiology, and outcomes, and determined the risk factors associated with the occurrence of CRKP and crude mortality due to K. pneumoniae infections. RESULTS Sixty-eight ASOT recipients (5.4%) experienced 78 episodes of K. pneumoniae infection. Among these, 20 patients (29.4%) died. The independent risk factors associated with mortality were multiple infected organs or sites (odds ratio=22.034, 95% confidence intervals=4.348-111.653, P=0.001) and septic shock (odds ratio=27.090, 95% confidence intervals=1.841-398.512, P=0.016). Risk factors associated with acquisition of CRKP were multiple infected organs or sites (odds ratio=3.056, 95% confidence intervals=1.091-8.556, P=0.033). CONCLUSIONS K. pneumoniae infections, especially CRKP, frequently occurred among ASOT recipients, with a high mortality rate. Multiple infected organs or sites and septic shock were predictors of crude mortality caused by K. pneumoniae infections, while CRKP infections were associated with multiple infected organs or sites. Greater efforts are needed towards improved antibiotic administration, early diagnosis and precise treatment, recognition of septic shock, and reduced length of hospitalization.

Preoperative abnormal body composition is closely related to bacteremia after living donor liver transplantation

OBJECTIVE

Infection is the most critical cause of early death after liver transplantation (LT). However, the effect of preoperative body composition on bacteremia after LT is unclear. The aim of this study was to examine the effects of preoperative body composition on bacteremia after living donor LT (LDLT).

METHODS

The study comprised 277 patients who underwent LDLT at Kyoto University, Kyoto, Japan, between January 2008 and June 2016. We evaluated body composition parameters including skeletal muscle mass index (SMI), intramuscular adipose tissue content (IMAC), and visceral-to-subcutaneous adipose tissue area ratio (VSR) using preoperative plain computed tomography at the L3 level. We compared the incidence of bacteremia, species, period of antibiotic administration, mortality due to bacteremia, and survival rates according to the number of abnormal body composition factors (low SMI, high IMAC, and high VSR). Moreover, risk factors for post-transplant bacteremia were examined.

RESULTS

Incidence of bacteremia was significantly higher in patients with three abnormal factors (47.1%), two factors (42%), or a single factor (37%) than in patients with no factors (22.5%; P = 0.027). Species of bacteremia did not differ significantly among the four groups. The period of antibiotic administration was significantly shorter (P = 0.039) and mortality of patients with bacteremia and survival rates were significantly better (P < 0.001, each) in patients with no factors. Multivariate analysis identified ABO incompatibility (P = 0.002) and low SMI (P = 0.045) as independent risk factors for bacteremia after LT.

CONCLUSION

Preoperative abnormal body composition was closely related to bacteremia after LDLT.

Challenges in the Diagnosis and Management of Bacterial Lung Infections in Solid Organ Recipients: A Narrative Review

Respiratory infections pose a significant threat to the success of solid organ transplantation, and the diagnosis and management of these infections are challenging. The current narrative review addressed some of these challenges, based on evidence from the literature published in the last 20 years. Specifically, we focused our attention on (i) the obstacles to an etiologic diagnosis of respiratory infections among solid organ transplant recipients, (ii) the management of bacterial respiratory infections in an era characterized by increased antimicrobial resistance, and (iii) the development of antimicrobial stewardship programs dedicated to solid organ transplant recipients.

Carbapenemase-Producing Bacterial Infections in Patients With Liver Transplant

Carbapenemase-producing Enterobacteriacea (CPE) cause serious and life-threatening infections. They are resistant to carbapenems and many other classes of commonly used antimicrobial agents; therefore, managing infections caused by them poses a substantial challenge in clinical practice. They can also cause morbidity and mortality in patients with liver transplant. A retrospective analysis of CPE culture-positive patients with a history of liver transplant can help to examine the epidemiology and microbiology of these bacteria, as well as gain information on the possible infection sources, susceptibility patterns, and expected mortality in infected populations. In addition, study of these bacteria could help formulate a consensus on the appropriate use of empirical and directed antibiotic therapy, which can effectively reduce infections in these patients. We reviewed the medical records of 142 subjects who underwent liver transplantation at Ankara University Hospital, a 1900-bed tertiary care university hospital, in Ankara, Turkey, between January 2014 and August 2018. Patients showing signs of infection with culture positivity for CPE-producing organisms were included from the study. Statistical analysis was performed and a value of P < .05 is considered statistically significant. In most cases, the source of infection was the abdomen. Klebsiella species was also predominant in these cases. Model for End-Stage Liver Disease scores and length of hospital stay were higher and statistically significant when compared to patients who were CPE negative. Mortality was highest in the CPE-positive group. Infection is the most important cause of mortality and morbidity after liver transplantation and increases the cost of treatment. Regarding the culture sensitivity patterns and resistance mode, empirical therapy with carbapenems does not produce a solid result. The high mortality observed with these infections reflects very limited therapeutic options.

Minimizing central line-associated bloodstream infections in a high-acuity liver transplant intensive care unit

BACKGROUND

Increases in liver transplant patient perioperative acuity have resulted in frail immunosuppressed patients at elevated risk for nosocomial infections. Avoiding central line-associated bloodstream infections (CLABSIs) is paramount to facilitate transplantation and post-transplant recovery. In 2015, our liver transplant intensive care unit (ICU) CLABSIs accounted for more than 25% of all CLABSI at our institution. We therefore undertook a multidisciplinary collaborative among clinical epidemiology, nursing, transplant surgery, and critical care to eliminate CLABSI events.

METHODS

From 2014-2016, using Lean methodology and plan-do-study-act (PDSA) cycles, 14 interventions were implemented in the liver transplant ICU. Interventions were aimed at infection prevention, care standardization, and team-based monitoring. Implementation used quality improvement methodology including audit and feedback, education, standardization, multidisciplinary stakeholder involvement, and PDSA cycles. Process measures were monitored and audited. CLABSI rates per 1,000 central venous catheter (CVC) days were tracked by clinical epidemiology.

RESULTS

During the intervention, 901 CVC catheter audits were completed. Improvements were seen on all process measures, and complete compliance increased from 25%-67%. CLABSI infection rates dropped from 4.2 to 1.8 in 1,000 CVC days, with an average of less than 1 CLABSI per month. This marked a 61.2% annual reduction, which correlated with an estimated $935,000 annual savings.

CONCLUSION

Concerted ongoing multidisciplinary collaboratives are essential to minimize CLABSI and optimize value and quality in a challenging, high-acuity patient population.

Bacteremia in kidney transplant recipients: Burden, causes, and consequences

Bacteremia is an important complication after kidney transplantation. We examined bacteremia and its outcomes in a large cohort of kidney transplant recipients. Kidney transplants from 1-Jul-2004 to 1-Dec-2014 at the Toronto General Hospital were eligible for study inclusion. Bacteremia was defined as two blood culture positives for common skin contaminants or one blood culture positive for other organisms. The cumulative incidence of first bacteremia was estimated using the Kaplan-Meier method, and risk factors were examined in a Cox proportional hazards model. The risk of graft failure or death was assessed in a time-dependent Cox model. Over follow-up, 154 of 1333 patients had at least one bacteremia episode. The cumulative incidence of first bacteremia was 6.8% (6 months) and 11.9% (5 years). Risk factors included recipient diabetes mellitus, time on dialysis, dialysis modality, delayed graft function, donor age, and donor eGFR. Bacteremia increased the risk of total graft failure (hazard ratio 2.11 [95% CI: 1.50, 2.96]), death-censored graft failure (1.73 [0.99, 3.02]), and death with graft function (2.52 [1.63, 3.89]). In conclusion, bacteremia is common after kidney transplantation and impacts both graft and patient survival. Identifying high-risk patients for targeted preventive strategies may reduce the burden and adverse consequences of this important complication.

Risk factors for infection after pediatric lung transplantation

Although infection is the leading cause of death in the first year following pediatric lung transplantation, there are limited data on risk factors for early infection. Sepsis remains under-recognized and under-reported in the early post-operative period for lung transplant recipients (LTR). We evaluated the incidence of infection and sepsis, and identified risk factors for infection in the early post-operative period in pediatric LTRs. A retrospective review of medical records of LTRs at a large quaternary-care hospital from January 2009 to March 2016 was conducted. Microbiology results on days 0-7 after transplant were obtained. Sepsis was defined using the 2005 International Pediatric Consensus Conferencecriteria. Risk factors included history of recipient and donor infection, history of multi-drug resistant (MDR) infection, nutritional status, and surgical times. Among the 98 LTRs, there were 22 (22%) with post-operative infection. Prolonged donor ischemic time ≥7 hours, cardiopulmonary bypass(CPB) time ≥340 minutes, history of MDR infection and diagnosis of cystic fibrosis were significantly associated with infection. With multivariable regression analysis, only prolonged donor ischemic time remained significant (OR 4.4, 95% CI: 1.34-14.48). Further research is needed to determine whether processes to reduce donor ischemic time could result in decreased post-transplant morbidity.

Effect of Selective Antibiotic Pressure on the MLS-B Phenotype in Methicillin-Resistant Staphylococcus aureus Strains Originating From Patients From Transplantation Wards: 24 Years of Observations

INTRODUCTION

Staphylococcus aureus infection, and health care-associated-methicillin resistant S aureus (HA-MRSA) in particular, is a serious risk for patients treated with organ transplantation. The frequent combined resistance of these bacteria to macrolides, lincosamides, and streptogramin-B (MLS-B) limits the use of these drugs in therapy.

AIM

Evaluation of the mechanism of MLS-B resistance among HA-MRSA strains derived from patients treated in surgical-transplantation wards, over a 24-year period, and assessment of correlation of clindamycin use and resistance phenotype.

MATERIALS AND METHODS

One hundred and twelve HA-MRSA strains from patients in surgical-transplantation wards (clinical hospital, Warsaw), hospitalized in the period from 1991 to 2014. Methicillin-resistance was determined using phenotypic and genetic methods by detecting the mecA gene. Erythromycin/clindamycin resistance was determined by E-test, the iMLS-B (inductive) and cMLS-B (constitutive) phenotypes by the D-test method. The number of defined daily doses (DDD), statistically per 1000 person-days, was calculated in accordance with the WHO guidelines.

RESULTS

Resistance to erythromycin/clindamycin in MRSA strains increased from 1991 to 2004-2007 from 64.7/11.8% to 100/76.9%, respectively. The frequency of the cMLS-B phenotype in the years 1991/2010-2011/2012 was 5.9%/76.9%/69.7%, respectively, and correlated with the increased use of clindamycin in the examined wards. In 2012, the percentage of MLS-B-sensitive isolates increased from 3.9 to 21.7%, while constitutive resistance decreased to 69.7%, which correlated with a decrease in the use of clindamycin.

CONCLUSIONS

The proportion of cMLS-B to iMLS-B phenotypes in HA-MRSA is related to the amount of clindamycin used in hospital wards. Limiting the selection pressure of antibiotics can lead to complete loss of resistance or return to the inductive mechanism of its regulation.

Epidemiology and management of healthcare-associated bloodstream infections in non-neutropenic immunosuppressed patients: a review of the literature

Advancements in medicine have led to a considerable increase in the proportion of patients living with severe chronic diseases, malignancies, and HIV infections. Most of these conditions are associated with acquired immune-deficient states and treatment-related immunosuppression. Although infections as a result of neutropenia have long been recognized and strategies for management were developed, non-neutropenic immunosuppression has been overlooked. Recently, community-acquired infections in patients with frequent, significant exposure to healthcare settings and procedures have been classified as 'healthcare-associated infections' since they are more similar to hospital-acquired infections. Most of the non-neutropenic immunosuppressed patients have frequent contact with the healthcare system due to their chronic and severe diseases. In this review, we focus on the healthcare-associated bloodstream infections in the most common non-neutropenic immunosuppressive states and provide an update of the recent evidence for the management of these infections.

Bacterial infections after pediatric heart transplantation: Epidemiology, risk factors and outcomes

BACKGROUND

Bacterial infections represent a major cause of morbidity and mortality in heart transplant recipients. However, data describing the epidemiology and outcomes of these infections in children are limited.

METHODS

We analyzed the Pediatric Heart Transplant Study database of patients transplanted between 1993 and 2014 to determine the etiologies, risk factors and outcomes of children with bacterial infections post-heart transplantation.

RESULTS

Of 4,458 primary transplants in the database, there were 4,815 infections that required hospitalization or intravenous therapy, 2,047 (42.51%) of which were bacterial. The risk of bacterial infection was highest in the first month post-transplant, and the bloodstream was the most common site (24.82%). In the early post-transplant period (<30 days post-transplant), coagulase-negative staphylococci were the most common pathogens (16.97%), followed by Enterobacter sp (11.99%) and Pseudomonas sp (11.62%). In the late post-transplant period, community-acquired pathogens Streptococcus pneumoniae (6.27%) and Haemophilus influenzae (2.82%) were also commonly identified. Patients' characteristics independently associated with acquisition of bacterial infection included younger age (p < 0.0001) and ventilator (p < 0.0001) or extracorporeal membrane oxygenation (p = 0.03) use at time of transplant. Overall mortality post-bacterial infection was 33.78%, and previous cardiac surgery (p < 0.001) and multiple sites of infection (p = 0.004) were independent predictors of death.

CONCLUSIONS

Bacteria were the most common causes of severe infections in pediatric heart transplant recipients and were associated with high mortality rates. The risk of acquiring a bacterial infection was highest in the first month post-transplant, and a large proportion of the infections were caused by multidrug-resistant pathogens.

Factors influencing mortality in abdominal solid organ transplant recipients with multidrug-resistant gram-negative bacteremia

BACKGROUND

Although multidrug-resistant (MDR) gram-negative bacteremia (GNB) has been recognized as an important cause of morbidity and mortality among abdominal solid organ transplant (ASOT) recipients, there are no data on its prognostic factors after an interim standard definition of MDR was proposed in 2012. The objective of this study was to describe the epidemiology, microbiology, and predictors of infection-related 30-day mortality in ASOT recipients with MDR GNB.

METHODS

We performed a retrospective, double-center analysis of ASOT patients with MDR GNB over a 13-year study period. Univariate and multivariate analyses were performed to identify the risk factors for mortality.

RESULTS

During the observational period, 2169 subjects underwent ASOT. Ninety-nine episodes of MDR GNB were diagnosed in 91 (4.6%) ASOT recipients, with a predominance of E.coli (29 isolates, 29.3%) and A.baumanii (24 isolates, 24.2%). The median age of these 91 recipients was 45 years (interquartile range 35-54). Mortality after the first episode of MDR GNB was 39.6% (36 deaths). The univariate analysis identified the following variables as predictors of MDR GNB-related mortality: lung focus (P = 0.001),nosocomial origin (P = 0.002), graft from donation after cardiac death or deceased donors (P = 0.023), presence of other concomitant bloodstream infection (P < 0.001), temperature of 40 °C or greater at the onset of MDR GNB (P = 0.039), creatinine > 1.5 mg/dl (P = 0.006), albumin < 30 g/L (P = 0.009), platelet count < 50,000/mm3 (P < 0.001), and septic shock (P < 0.001). In the multivariate logistic regression analysis, septic shock (odds ratio (OR) = 160.463, 95% confidence interval (CI) = 19.377-1328.832, P < .001), as well as creatinine > 1.5 mg/dl (OR = 24.498, 95% CI = 3.449-173.998, P = 0.001), nosocomial origin (OR = 23.963, 95% CI = 1.285-46.991, P = 0.033), and presence of other concomitant bloodstream infections (OR = 27.074, 95% CI = 3.937-186.210, P = 0.001) were the variables associated with MDR GNB-related 30-day mortality.

CONCLUSIONS

MDR GNB was associated with high morbidity and mortality in ASOT recipients, with a predominant causative organisms being E.coli and A.baumanii. Nosocomial origin, as well as presence of other concomitant bloodstream infections, increased creatinine level and septic shock were the main predictors of MDR GNB-related 30-day mortality.

A Rationale for Age-Adapted Immunosuppression in Organ Transplantation

Demographic changes are associated with a steady increase of older patients with end-stage organ failure in need for transplantation. As a result, the majority of transplant recipients are currently older than 50 years, and organs from elderly donors are more frequently used. Nevertheless, the benefit of transplantation in older patients is well recognized, whereas the most frequent causes of death among older recipients are potentially linked to side effects of their immunosuppressants.Immunosenescence is a physiological part of aging linked to higher rates of diabetes, bacterial infections, and malignancies representing the major causes of death in older patients. These age-related changes impact older transplant candidates and may have significant implications for an age-adapted immunosuppression. For instance, immunosenescence is linked to lower rates of acute rejections in older recipients, whereas the engraftment of older organs has been associated with higher rejection rates. Moreover, new-onset diabetes mellitus after transplantation is more frequent in the elderly, potentially related to corticosteroids, calcineurin inhibitors, and mechanistic target of rapamycin inhibitors.This review presents current knowledge for an age-adapted immunosuppression based on both, experimental and clinical studies in and beyond transplantation. Recommendations of maintenance and induction therapy may help to improve graft function and to design future clinical trials in the elderly.

Bloodstream infections after solid-organ transplantation

Solid-organ transplantation (SOT) has become the preferred strategy to treat a number of end-stage organ disease, because a continuous improvement in survival and quality of life. While preventive strategies has decreased the risk for classical opportunistic infections (such as viral, fungal and parasite infections), bacterial infections, and particularly bloodstream infections (BSIs) remain the most common and life-threatening complications in SOT recipients. The source of BSI after transplant depends on the type of transplantation, being urinary tract infection, pneumonia, and intraabdominal infections the most common infections occurring after kidney, lung and liver transplantation, respectively. The risk for candidemia is higher in abdominal-organ than in thoracic-organ transplantation. Currently, the increasing prevalence of multi-drug resistant (MDR) Gram-negative pathogens, such as extended-spectrum betalactamase-producing Enterobacteriaciae and carbapenem-resistant Klebsiella pneumoniae, is causing particular concerns in SOT recipients, a population which presents several risk factors for developing infections due to MDR organisms. The application of strict preventive policies to reduce the incidence of post transplant BSIs and to control the spread of MDR organisms, including the implementation of specific stewardship programs to avoid the overuse of antibiotics and antifungal drugs, are essential steps to reduce the impact of post transplant infections on allograft and patient outcomes.

Death and kidney allograft dysfunction after bacteremia

BACKGROUND

Some studies have reported causal associations between bacteremia and mortality or allograft loss in kidney transplant recipients (KTR). However, few studies have assessed the clinical course of kidney function and the risk of acute allograft rejection after bacteremia.

METHODS

We retrospectively reviewed 902 kidney transplants performed at Nagoya Daini Red Cross Hospital between January 1, 2002 and March 31, 2014. Forty-five living donor kidney transplant recipients with single bacteremia were included. We analyzed death, change in kidney function, and development of acute allograft rejection 12 months after bacteremia according to the following groups: primary source of bacteremia (urinary tract or other sources), site of acquisition (community acquired or nosocomial), severity (not meeting the systemic inflammatory response syndrome criteria and sepsis or severe sepsis and septic shock), empiric antibiotic use (appropriate or inappropriate), and baseline kidney function (estimated glomerular filtration rate ≤44.7 or ≥44.8 ml/min).

RESULTS

Urinary tract infection (UTI) was the leading cause of bacteremia (68.9 %), and Escherichia coli was the most common pathogen. Three cases (6.7 %) died of infection that caused bacteremia within 12 months. Pneumonia accounted for two-thirds. Kidney function declined 1 week after bacteremia (P < 0.05), particularly in severe cases. Thereafter, kidney function was comparable to baseline level in each group (P ≥ 0.05). Severe UTI was associated with subsequent acute allograft rejection (P = 0.03).

CONCLUSIONS

Pneumonia in KTR should be managed with caution. Kidney function generally returned to baseline level after bacteremia. However, severe UTI may be associated with subsequent acute allograft rejection.

Factors influencing mortality in solid organ transplant recipients with bloodstream infection

Although bloodstream infection (BSI) is a major cause of mortality after solid organ transplantation, information regarding its prognostic factors is scarce. To identify risk factors for 30-day mortality in solid organ transplant (SOT) recipients with BSI, we prospectively recorded all episodes of BSI occurring in adult SOT recipients from January 2007 to October 2014 at a university hospital. We identified 361 consecutive episodes of BSI involving 246 patients. The 30-day case-fatality rate from the onset of BSI was 11.4%. Factors independently associated with 30-day mortality in a logistic regression analysis were shock at presentation (OR 13.658; 95% CI 5.985-31.168), acute graft rejection in the previous 6 months (OR 3.681; 95% CI 1.059-12.795), and a platelet count of <50,000 × 10(9)/L (OR 3.070; 95% CI 1.173-8.038). Kidney recipients were the patients with the best prognosis (OR 0.375; 95% CI 0.156-0.900). Our findings may help to identify SOT recipients with BSI who are at the highest risk of death.