Risk factors and etiology of repeat infection in kidney transplant recipients

Infections in the first year of living related kidney transplantation in a young transplant cohort

BACKGROUND

Infection after a kidney transplant is a serious cause of morbidity and mortality. Weighing the risks and benefits of immunosuppression is of paramount importance for patient wellbeing and transplant survival.

METHODS

This is a prospective observational study exploring the variety of bacterial, viral and fungal infections occurring within the first year of living related kidney transplantation in a young transplant cohort. Fifty-one kidney transplant recipients (KTR) between the age of 18 and 45 who had a kidney transplant between Jan 2020 and Jan 2022 were enrolled and followed up for one year. Primary outcome was the occurrence of infection.

RESULTS

Twenty-four patients (47%) recorded a collective 33 episodes of infection. Seven patients had repeated infections and 17 had single infections. Twenty-seven patients had an uneventful year with no infections recorded. Commonest infection was lower urinary tract infection (UTI) (27.3%) followed by SARS-COV2 and Herpes Zoster (15.2%). The commonest pathogens causing lower UTI were Escherichia coli (E coli) (21.2%) and Klebsiella (18.2%). Median Tacrolimus level was (7.8) ng/ml in KTR with infection and (8.95) ng/ml in KTR without infection, p = 0.21. Median Haemoglobin (IQR) was (10.2) g/dl (7.8-14) gm/dl in KTR with infection compared to (10.8) g/dl (7.3-15.3) in KTR without infection odds ratio (OR) = 0.78, confidence interval (CI) (0.5-1.1); p = 0.16.In KTR with infection 25% had donors above the age of 60 compared to 11% in KTR without infection ( OR 2.6,CI (0.5-12), p = 0.2). Post transplant diabetes (PTDM) occurred in (25%) in KTR with infection compared to those without, but that was not statistically significant p = 0. 365.In KTR without infection, 59.3% had a preemptive transplant compared to 20.8% in the group with infection (OR = 0.18; 95% CI: 0.052-0.631; p = 0.007). Median tacrolimus was 7.8 ng/ml in KTR with single infection compared to 7.7 ng/ml in KTR with repeated infections.

CONCLUSION

This study shows that the commonest infection occurring in the first-year post kidney transplant was lower urinary tract infection followed by SARS-COV2 and Herpes Zoster. There was no difference in trough tacrolimus or haemoglobin levels between KTR who developed infection with those who did not.

CYP3A5 Polymorphism in Renal Transplantation: A Key to Personalized Immunosuppression

BACKGROUND

Tacrolimus is essential for the maintenance of immunosuppression after a kidney transplant. CYP3A5 is the gene that metabolizes tacrolimus, and polymorphism in this gene affects the metabolizing status.

AIM

To assess the genetic polymorphism status of patients undergoing kidney transplantation and determine its impact on graft function and complications in the post-transplant period.

METHODS

We retrospectively included the patients who had undergone a kidney transplant and had positive genetic polymorphism of the CYP3A5 gene. Based on loss of alleles, patients were categorized as non-expresser (loss of both alleles), intermediate expresser (loss of one allele), and expresser (no loss of allele) denoted by CYP3A5*3/*3, CYP3A5*1/*3, and CYP3A5*1/*1, respectively. Data were analyzed with descriptive statistics.

RESULTS

Of 25 patients, 60%, 32%, and 8% were non-expressers, intermediate-expressers, and expressers, respectively. The mean tacrolimus trough concentration to dose ratio after 6 months of the transplant was higher in non-expressers than intermediate-expressers and expressers (213 vs 85 and 46 ng/mL/mg/kg/d, respectively). The graft function was normal in all 3 groups except for graft rejection 1 patient in the expresser group. Compared with expressers, urinary tract infections (42.9% and 62.5%) and new-onset diabetes after transplantation (28.6% and 12.5%) were more frequent in non-expresser and intermediate expressers, respectively. The proportion of patients developing new-onset diabetes after transplantation was lower with the pre-transplant diagnosis of CYP3A5 polymorphism (16.7% vs 23.1%).

CONCLUSION

Genotype-based dosing of tacrolimus helps achieve the desired therapeutic concentrations that can help to optimize graft outcomes and reduce the tacrolimus-related adverse effects. Pre-transplant evaluation of CYP3A5 can be more helpful in planning treatment strategies for optimized outcomes after kidney transplantation.

Bacterial Urinary Tract Infection and Early Asymptomatic Bacteriuria in Kidney Transplantation Still Negatively Affect Kidney Transplant Outcomes in the Era of Modern Immunosuppression and Cotrimoxazole Prophylaxis

Risk factors and consequences of urinary tract infection (UTI) post-kidney transplant have been variously reported by studies that were heterogenous in immunosuppressants and prophylactic protocols. We aimed to clarify the risks and consequences of UTI in kidney transplant recipients with post-transplantation cotrimoxazole prophylaxis in the context of modern immunosuppression. This retrospective cohort included kidney transplant recipients receiving tacrolimus, mycophenolate, prednisolone, and cotrimoxazole for bacterial UTI prophylaxis. Recipients were categorized into non-UTI and UTI groups. Asymptomatic bacteriuria (ASB) was screened in the first 3 months and was evaluated for association with UTI. Of 348 kidney transplant recipients, 129 were in the UTI group and 219 in the non-UTI group. UTI risk factors were female sex, body mass index ≥ 25 kg/m², human leukocyte antigen mismatch, and panel reactive antibody ≥ 50%. Recipients with recurrent UTI had inferior allograft function compared with non-UTI recipients. Patient survival was significantly lower in recipients with UTI in the first post-transplant month. Higher degree of immunosuppressions was associated with recurrent UTI and drug-resistant organisms. In conclusion, UTI continues to negatively affect graft function and survival of kidney transplant recipients. Treating ASB in the first 3 months did not reduce the UTI incidence in the first transplantation year.

Optimal blood levels of (extended-release) tacrolimus in living donor kidney transplantation to prevent de novo donor-specific antibody production: A retrospective cohort study

Chronic antibody-mediated rejection, caused by de novo donor-specific antibody (dnDSA) production, results in poor graft survival. To prevent dnDSA production, optimal blood levels of immunosuppressive drugs in living donor kidney transplant recipients were determined. A total of 772 recipients underwent living donor kidney transplantation between January 2008 and December 2017. Graft survival and risk factors for dnDSA production were investigated in 647 recipients. Optimal blood levels of tacrolimus (TAC) and extended-release TAC (TACER) were measured in recipients receiving steroids and mycophenolate mofetil, combined with TAC (n = 53) or TACER (n = 135). Receiver operating characteristic (ROC) curve analysis and comparisons between dnDSA-negative and dnDSA-positive recipients were carried out. The Kaplan-Meier method revealed significantly poor graft survival in dnDSA-positive recipients (P < 0.001). Cox regression models indicated calcineurin inhibitor withdrawal as a significant risk for dnDSA production (P < 0.001; hazard ratio 6.637; 95% confidence interval 2.667-6.517). Average trough levels of TAC and TACER in dnDSA-negative recipients were significantly higher than those in dnDSA-positive recipients (4.88 vs 3.69 ng TAC/ml, P = 0.023, and 4.60 vs 3.85 ng TACER/ml, P = 0.001). ROC curve analysis indicated 4.325 and 3.990 ng/ml as the best trough levels under TAC- and TACER-based regimens, respectively, to prevent dnDSA production (areas under the curve: 0.788 and 0.813, respectively). Maintenance of the trough levels of TAC > 4.325 ng/ml and TACER > 3.990 ng/ml may prevent dnDSA production.

Microbial Predominance and Antimicrobial Resistance in a Tertiary Hospital in Northwest China: A Six-Year Retrospective Study of Outpatients and Patients Visiting the Emergency Department

Background

With the wide use of antibiotics, antimicrobial resistance becomes a serious issue. Timely understanding of microbial pathogen profiles and the change of antimicrobial resistance provide an important guidance for effective and optimized use of antibiotics in local healthcare systems. The aim was to investigate the characteristics of microbial species and their antimicrobial resistances in a tertiary hospital with an Emergency Department and outpatient clinics for a period of six years. Methodology. A retrospective study was conducted using the HIS database of a tertiary hospital between 2013 and 2018. Antimicrobial susceptibility was tested by automated systems and/or the Kirby-Bauer disc diffusion method. The data were analyzed using the WHONET 5.6 software. The Cochran-Armitage test was used to study the trends over the period of research.

Results

In a total of 19,028 specimens submitted for microbial tests during the period from 49 units of the hospital, only the samples from the Emergency Department and Kidney Transplantation Clinic showed an annually significant increase (P < 0.001). More than 200 species with 46.4% gram-positive cocci and 45.3% gram-negative bacilli were identified in the 3,849 nonrepetitive isolates. The methicillin-resistant S. aureus and S. epidermidis rates were 25.1% and 74.6%, respectively. 60.9% E. coli and 33.5% K. pneumonia samples carried extended-spectrum-β-lactamase. All Staphylococci and Enterococci samples were not resistant to linezolid, vancomycin, and tigecycline. In addition, only 0.01% E. coli, 1.1% K. pneumonia, and 18.7% P. aeruginosa isolates showed resistance to carbapenems.

Conclusions

Vancomycin, linezolid and tigecycline were the most effective antibiotics for outpatients with gram-positive infection. Carbapenems were the most effective antibiotics for gram-negative infection. There was no significant annual increase of common multidrug resistances.

Analysis of risk factors for early urinary tract infection after kidney transplantation

Background

Urinary tract infection (UTI) is the most common kind of infection in the early stage after kidney transplantation. Although many studies have investigated the risk factors for UTI following kidney transplantation, few studies have focused on the risk factors for UTI in the early stage after transplantation.

Methods

The early-stage data of patients who underwent kidney transplantation between January 2018 and December 2019 in a first-class tertiary hospital in Suzhou, China, were retrospectively analyzed. The general and UTI information of the recipients was subjected to univariate analysis. Variables with statistical significance in the univariate analysis were included in a multivariate logistic regression model.

Results

A total of 129 recipients were recruited, among whom 62 patients had a UTI in the early stage after kidney transplantation (48.1%), and the median (interquartile range) of onset time was 5 (4, 10) days after the surgery. A total of 324 strains of UTI pathogens were detected in the 62 recipients after kidney transplantation, 279 of which were gram-negative bacilli (86.1%). Multivariate logistic regression analysis showed that female sex and delayed graft function (DGF) were independent risk factors for early-stage UTI, with odds ratios of 0.095 and 3.753, respectively.

Conclusions

The incidence of early UTI after kidney transplantation is high. Females and DGF patients are more prone to UTIs. Comprehensive prevention and treatment measures should be taken as early as possible against the risk factors to reduce the incidence of UTI.

How to Treat Asymptomatic and Symptomatic Urinary Tract Infections in the Kidney Transplant Recipients?

Patients with end-stage renal functions are treated with renal transplantation. After the transplantation, kidney transplant recipients (KTR) are at the risk of urinary tract infection (UTI). UTI in KTR may be symptomatic and asymptomatic. Asymptomatic UTI is the presence of the organisms without any signs and symptoms. There are various ways suggested in the published research papers to deal with UTI in the KTR. The goal of this literature review is to explore how to treat symptomatic and asymptomatic UTI in KTR. A PubMed search was conducted to identify the studies explaining the methods used to deal with UTI in KTR. A total number of 2158 articles were found while searching for regular keywords; however, we found 996 articles with the medical subject heading (Mesh) keywords. After applying the inclusion/ exclusion criteria, 56 articles with the regular keywords search and 29 articles with the Mesh keywords search were selected. These articles included 24 randomized clinical trials, 16 clinical trials, 7 review articles, 5 case reports, 2 controlled clinical trials, 2 observational studies, and 1 cross-sectional study. Our analysis has shown that the early removal of the stent after the transplantation and the use of antibiotics are beneficial in reducing the incidence of symptomatic UTI in the KTR; whereas, treating asymptomatic UTI in KTR has not been proven helpful in reducing the incidence of developing symptomatic UTI later on.

Prognostic Performance of SOFA, qSOFA, and SIRS in Kidney Transplant Recipients Suffering from Infection: A Retrospective Observational Study

INTRODUCTION

The prognostic performance of scoring systems for illness severity in infectious kidney transplant recipients (KTRs) is rarely reported. We investigated the ability of the scores for the quick Sequential Organ Failure Assessment (qSOFA), Sequential Organ Failure Assessment (SOFA) and Systemic Inflammatory Response Syndrome (SIRS) to predict in-hospital mortality, intensive care unit (ICU) admission and mechanical ventilation (MV) requirement.

METHODS

This was a second analysis of a retrospective observational study. Scores for SIRS, SOFA and qSOFA were calculated upon hospitalization (infection onset was before hospitalization) or on the day of infection onset (infection episodes were during hospitalization). The primary outcome was in-hospital mortality. The secondary outcomes were ICU admission and MV requirement. Binary logistic regression and area under the receiver operating characteristic curve (AUC) were employed to assess prognostic performance.

RESULTS

A total of 161 infectious episodes occurred in 97 KTRs. Forty patients (41%) experienced more than one episode. The SOFA score was available in 161 infections, and scores for qSOFA and SIRS were available in 160 infections. The SIRS score was not different between KTRs with opposite outcomes. The qSOFA score was higher in infections necessitating MV. The SOFA score was significantly higher in the deceased, those needing ICU admission, MV, and for those with positive etiology results. The SOFA score was the only independent predictor of in-hospital mortality, ICU admission, and MV requirement, and the AUCs were 0.879, 0.815, and 0.784, respectively. The optimum cutoff value of predicting the three outcomes was SOFA score ≥ 3.

CONCLUSIONS

The SOFA score (but not those for SIRS and qSOFA) independently predicted in-hospital mortality, ICU admission, and MV requirement in infectious KTRs.