Pathogenic Microbiological Analysis Of Urinary Tract Infection After Kidney Transplantation And Clinical Characteristics Of Disease Progression Of Acute Lobar Nephronia

Part 1:Pathogenic microbiological analysis of urinary tract infection after kidney transplantation.Objective:To explore the distribution of pathogenic microorganisms in the blood and urine of patients with urinary tract infection(UTI)after kidney transplantation,and to explore the significance of mNGS in the identification of pathogenic microorganisms in UTI patients after kidney transplantation,in order to make clinical suggestions for the rapid diagnosis and targeted treatment of UTI after kidney transplantation.Methods:The case information of 46 hospitalized patients diagnosed with UTI in Nanfang Hospital of Southern Medical University from October 1,2019 to October 31,2021 was analyzed,and their blood and urine samples were collected for traditional pathogen culture and mNGS microbial detection,and the detection efficiency of the two pathogen detection methods was compared.The distribution of pathogenic microorganisms in positive specimens was analyzed,and their distribution in blood and urine specimens was compared,and the similarities and differences between male patients and female patients were analyzed.Results:A total of 136 specimens were taken from 46 patients with UTI after kidney transplantation,of which 69 specimens tested positive.The positive rate of traditional pathogen culture method was 13%,and the positive rate of mNGS detection was 78%,which was statistically significant(p<0.001).A total of 29 pathogens were detected in all positive specimens,of which G-bacteria accounted for the largest proportion(38%,26/69);It was followed by viruses(36%,25/69).The detection rate of G-bacteria in urine specimens was significantly higher than that in blood specimens(p=0.05),and the detection rate of fungi in blood specimens was significantly higher than that in urine specimens(p=0.016).The detection rate of the virus in blood samples was higher than in urine samples(52.9%vs.30.8%).The detection rate of G-bacteria in urine specimens in female patients was significantly higher than that in male patients(p=0.025).Conclusions:For patients with UTI after kidney transplantation,mNGS has higher sensitivity than traditional culture methods,and the combination of traditional urine culture and NGS microbial detection technology can improve the detection rate and accuracy of pathogenic microorganisms.Most post-kidney transplant UTIs are bacterial UTIs,which are common with G-bacteria.Viruses are also common pathogens of UTIs,while fungi and specific pathogens are rare.The use of broad-spectrum antibiotics and high adherence in patients after kidney transplantation allow bacterial UTI to be controlled early and the bacteria are less susceptible to bloodshed.Viruria is often clinically overlooked and tends to progress to viremia.Fungi are mostly found in NGS sequencing.The anatomy and physiology of female patients make them more likely to develop bacterial and fungal infections than men.Part 2:Clinical characteristics of disease progression of Acute lobar nephroniaObjective:To explore the high-risk factors,clinical characteristics,pathogenesis,disease progression and outcome of Acute lobar nephronia(ALN)in recipients,thus reducing misdiagnosis and inadequate treatment.Methods:We retrospectively examined 302 kidney transplant recipients with the first UTI diagnosis from Nanfang Hospital of Southern Medical University(Guangzhou,China)between January 2005 and January 2021 to select those diagnosed with ALN.Besides,a literature search of ALN in renal allograft was conducted in PubMed between January 1979 and January 2021 with no language restriction.The general conditions,clinical symptoms and complications were collected to summarize the clinical characteristics and the high-risk factors of ALN in renal transplant allografts.Laboratory examination results(serum leukocyte count,neutrophil percentage,C reactive protein,creatinine,urinary leukocyte count and serum cytology levels of IL-2,TNF-?,IFN-r,IL-4,IL-4,IL-6,IL-10,IL-17)were all recorded to explore the pathogenesis.Additionally,the imaging findings were analyzed to summarize the disease progression.The treatment of all patients was recorded,and a long-term follow-up of 8 patients in our center was performed to further explore the progression and prognosis of the ALN in renal transplant allografts.Results:From 302 patients diagnosed with UTI,a total of 8 renal transplant recipients with ALN were identified in our center.Besides,6 cases were identified from the literature review.Among the 14 cases,the male to female ratio was 1:6,and the median age at transplantation was 36.5 years.According to statistics,84.6%received cadaveric donor kidneys,62.5%used ATG for immunoinduction after transplantation,and 53.8%had diabetes.Fever(85.7%)and pain or discomfort in the transplant allograft(71.4%)were the main clinical symptoms of the ALN after transplantation.Laboratory examination indicates the elevation of blood image,infection index and urinary white blood cell count,which could be accompanied by renal function injury.Additionally,the common pathogens in urine culture were Gram-negative bacteria.In the acute phase,the serum IL-6 and IL-10 levels increased significantly.According to the imaging results,the course of ALN after transplantation could be divided into three stages:the first stage is acute upper urinary tract infection period,the second stage is acute focal infection period,and the third stage is scar formation and absorption period after infection.All patients received antibiotic maintenance therapy with a mean duration of 15.6±8.9 days,and the clinical symptoms were relieved after 4.6 ± 3 days,while the renal function gradually recovered within 14 months after the development of ALN.Among the 8 patients in our center,7 patients developed chronic renal scar in allograft according to B ultrasound,and 2 patients progressed to graft kidney failure due to chronic rejection,while 4 patients developed BKV viruria and 3 patients had JCV viruria.Conclusions:Female,receiving cadaveric donor kidney,age 20-40 years at undergoing kidney transplant,immune induction with ATG,and concurrent diabetes are risk factors for the development of ALN in renal transplant allografts.The clinical symptoms of this disease are atypical,thus leading to misdiagnosis or missed diagnosis.Imaging examination can serve as the diagnostic basis of this disease.Retrograde infection of gram-negative bacteria is a major pathogenesis of ALN after transplantation,and IL-6 and IL-10 are typical cytokines in the disease course,which play important roles in the early stage of the disease.The course of ALN in renal transplant allografts can be divided into three stages:acute upper urinary tract infection period(Phase ?),acute focal infection period(Phase ?),treatment failure and renal scar formation(Phase ?).The disease can be quickly identified from other space-occupying lesions by imaging examination to avoid misdiagnosis.Besides,this disease is sensitive to antibiotic therapy,but a delayed diagnosis or inadequate therapy can lead to treatment failure.The prognosis of ALN after transplantation is satisfying without long-term damage of graft function.However,it' necessary to be alert to the occurrence of acute and chronic rejection.Recipients with this disease are susceptible to polyomavirus infection,which suggests the excessive immunosuppressed state.Therefore,the appropriate adjustment of the immunosuppressive agent dose may prevent the occurrence of this disease.