Study On Pathogens And Predisposing Factors Of Peritoneal Dialysis-Associated Peritonitis

Objectives:Peritoneal dialysis-associated peritonitis(PDAP)is a common and serious complication of peritoneal dialysis(PD)and an important cause of technical failure of PD.We designed a series of studies from both clinical and laboratory aspects.At the laboratory level,we detected a variety of monosaccharides in peritoneal dialysate of PDAP patients based on the difference in surface sugar composition of different pathogens,and explored the diagnostic value of different monosaccharides in PDAP pathogens.At the clinical level,the white blood cell(WBC)>100*10~6/L and polymorphonuclear leukocytes(PMN)≤50%in ascites after peritoneal dialysis catheterization,which is rarely involved in the guidelines,were studied.Material and Methods:Laboratory study:Peritoneal dialysate samples were collected from 90 peritoneal dialysis patients who were hospitalized in the Affiliated Hospital of Qingdao University from October 1,2020 to October 31,2021,including 52 non-peritonitis samples and 38peritonitis samples.24 Gram-positive bacterial peritonitis dialysate samples and 14 Gram-negative bacterial peritonitis dialysate samples.The concentrations of degraded mannose,glucose and fucose in all samples were measured by high performance liquid chromatography,and the differences in the levels of mannose,glucose and fucose in the three groups of dialysate samples were compared.Logistic regression was used to analyze the relationship between the monosaccharide levels and the occurrence of peritonitis and pathogens.The Receiver operator characteristic curve(ROC)was used to evaluate the diagnostic value of the monosaccharide levels for different pathogens in peritonitis.Clinical studies:A total of 223 patients who underwent peritoneal dialysis catheterization due to acute or chronic renal failure in the Department of Nephrology,the Affiliated Hospital of Qingdao University from January 1,2018 to April 30,2022 were retrospectively analyzed.The age was≥18 years old.A total of 193 patients were enrolled.According to the white blood cell count and the proportion of multinucleated white blood cells in ascites within 48 hours after operation,61 patients with increased white blood cell count and decreased proportion of multinucleated white blood cells(WBC>100*10~6/L,PMN%≤50%)were finally enrolled.According to whether peritoneal dialysis catheter-related peritonitis progressed within 1 month after surgery,61 patients were divided into peritonitis progression group(n=14)and ascites white blood cell count returned to normal group(n=47).The incidence and influencing factors of PDAP in patients with ascites WBC>100*10~6/L and PMN%≤50%were analyzed.Results:Laboratory results:(1)The levels of BMI,ALB,serum sodium,serum calcium and serum phosphorus in the peritonitis group were lower than those in the non-peritonitis group,and the level of CRP was higher than that in the non-peritonitis group(all P<0.05).Compared with the non-peritonitis group,the glucose concentration and fucose concentration in the peritonitis group were significantly decreased(P<0.01).Mannose concentration was different between gram-positive peritonitis and gram-negative peritonitis(P<0.01).(2)Logistic regression analysis showed that the decreased concentration of fucose was a risk factor for peritonitis(P<0.01).The decrease of mannose concentration was a risk factor for Gram-positive bacteria peritonitis(P<0.01).(3)ROC curve analysis showed that the concentration of fucose had high diagnostic value for peritonitis,AUC is0.820,95%CI(0.732,0.908),sensitivity is 71.05%,specificity is 84.62%,and the optimal cut-off value is 3.045umol/L.Mannose concentration is of high diagnostic value for gram-positive bacterial peritonitis,AUC is 0.863,95%CI(0.740,0.986),sensitivity is 78.57%,specificity is 83.33%,and the optimal cut-off value is 0.345umol/L.In gram-positive bacterial peritonitis,mannose level in peritoneal dialysate decreased significantly.Clinical research:(1)The levels of BNP and serum creatinine in patients who progressed to peritonitis within 1 month after surgery were higher than those in patients whose ascites white blood cell count returned to normal(P<0.05).In the group with WBC>100*106/L and PMN%≤50%,14 cases progressed to peritoneal dialysis catheter-related peritonitis within 1 month after operation,including 2 cases of peritonitis with positive ascites culture,and the pathogens were Staphylococcus capitis and Enterococcus faecalis.A chi-square analysis of antibiotic use found no difference in the incidence of peritonitis in the first month after surgery between those who received antibiotics and those who did not.(2)Logistic regression analysis showed that elevated BNP was a risk factor for the development of peritonitis in patients with WBC>100*10~6/L and PMN%≤50%.Conclusions:(1)The concentration of fucose degraded in peritoneal dialysate is an independent risk factor for peritonitis associated with peritoneal dialysis,and the concentration of mannose degraded in peritoneal dialysate is an independent risk factor for Gram-positive bacterial peritonitis.(2)The significant decrease of fucose concentration in dialysate can be used to indicate the occurrence of peritonitis.The decrease of mannose concentration in dialysate has certain diagnostic value for early diagnosis of Gram-positive bacterial peritonitis infection and guiding the selection of antibiotics.(3)Patients with WBC>100*10~6/L and PMN%≤50%should be closely monitored.If they have poor cardiac function,heart failure should be corrected actively,which will help to reduce the incidence of peritonitis.