Identification and characterization of SCCmec typing with psm-mec positivity in staphylococci from patients with coagulase-negative staphylococci peritoneal dialysis-related peritonitis

BACKGROUND

Peritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance.

METHODS

We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected.

RESULTS

Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene.

CONCLUSIONS

The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.

Peritoneal dialysis-related peritonitis caused by Rhodococcus corynebacterioides

A 57-year-old Japanese man on peritoneal dialysis developed peritoneal dialysis-associated peritonitis caused by Rhodococcus corynebacterioides. After the introduction of peritoneal dialysis, he had experienced four episodes of peritonitis, but the causative organism was not identified in any of episode. When he was hospitalized for the fifth episode of peritonitis, Rhodococcus corynebacterioides was detected in the ascitic fluid. He improved after an intraperitoneal administration of vancomycin (VCM) that was used based on the treatment of peritonitis caused by Corynebacterium spp. However, he then had repeated flare-ups and eventually required the removal of the peritoneal dialysis catheter due to recurrent peritonitis. 16S rRNA gene sequencing is generally needed to positively identify Rhodococcus corynebacterioides. In this case, we were able to rapidly identify the organism by using mass spectrometry and then apply this knowledge to the patient's treatment. To the best of our knowledge, this is the first reported case of peritoneal dialysis-associated peritonitis caused by Rhodococcus corynebacterioides.

A nomogram predicts cardiovascular events in patients with peritoneal dialysis-associated peritonitis

Objective

To predict the risk factors for cardiovascular events within 5 years in patients with peritoneal dialysis-associated peritonitis and establish a nomogram for clinical prediction.

Methods

A prediction model was established by conducting an observational study in 150 patients with peritoneal dialysis-associated peritonitis obtained from the Information Database of AnHui Medical University Affiliated Hospital. The nomogram was constructed using the multivariate COX regression model. The C-index and the calibration plot were used to assess the discrimination and calibration of the prediction model.

Results

The elderly [HR = 2.453 (1.071–5.619)], history of cardiovascular events [HR = 2.296 (1.220–4.321)], alkaline phosphatase [HR = 1.004 (1.002–1.005)] and culture-positive [HR= 2.173 (1.009–4.682)] were identified as risk predictors of cardiovascular events, while serum albumin [HR = 0.396(0.170–0.924)] was identified as protective predictors of cardiovascular events. Combined with clinical studies, we constructed a nomogram based on the minimum value of the Akaike Information Criterion or Bayesian Information Criterion. The C index of the nomogram is 0.732, revealing great discrimination and appropriate calibration. Through the total score of the nomogram and the result of ROC, we classify patients into high-risk groups (cardiovascular events group) and low-risk groups (no cardiovascular events group). Cardiovascular events were significantly different for patients in the high-risk group compared to the low-risk group (HR = 3.862(2.202–6.772; p < 0.001).

Conclusions

The current novel nomogram can accurately predict cardiovascular events in patients with peritonitis associated with peritoneal dialysis. However, external validation is required before the model can be used in clinic settings.

Neisseria elongata -mediated peritonitis in an end-stage renal disease patient on automated peritoneal dialysis, A case report and literature review

Introduction

Peritoneal dialysis (PD) can result in peritonitis, which frequently causes severe and near-fatal clinical implications if left untreated. Usually, Gram-positive bacteria are the most common organisms involved. Uncommonly recognized as the cause of peritonitis in PD patients, Neisseria Elongata is a gram-negative nasal and oropharyngeal normal flora organism.

Case presentation

We report a rare case of a 29-year-old man who had received automated peritoneal dialysis for six years and had Neisseria Elongata peritonitis.

Discussion

Several case Reports of niseria-related peritonitis may point to the potential pathogenicity of such organisms and suggest that many cases of culture-negative peritonitis may have been misdiagnosed. Poor nutrition and chronic kidney disease have been suggested as potential risk factors for Neisseria elongata peritonitis [8], both of which are present in our patient. With appropriate antibiotic use, most of the cases respond well to empirical treatment.

Conclusion

Although rare, Neisseria Elongata can lead to Peritoneal Dialysis catheter Peritonitis that, in some cases, require changing to hemodialysis.

Hypertriglyceridemia is a risk factor for treatment failure in patients with peritoneal dialysis-related peritonitis

OBJECTIVE

Disorders of triglycerides (TG) are common in patients with peritoneal dialysis (PD). Hypertriglyceridemia has been demonstrated in various infections. The association between triglycerides and the outcomes of peritoneal dialysis-related peritonitis (PDRP) was investigated in this study.

METHODS

We retrospectively investigated patients with PDRP from January 1, 2013 to October 31, 2020. Hypertriglyceridemia was defined as triglycerides ≥ 1.7 mmol/L. PDRP episodes were divided into two groups: hypertriglyceridemia and normal levels of triglycerides. The clinical and laboratory baseline data of the two groups were collected and compared. The association between triglycerides and treatment failure was analyzed by logistic regression analysis.

RESULTS

Ninety episodes in 66 patients were recorded in our center. Hypertriglyceridemia occurred in 38% (34/90) of episodes. Twenty-five episodes were not cured in 90 episodes (27.8%, 25/90). The levels of thrombocytes, high-sensitivity C-reactive protein (hs-CRP), low-density lipoprotein cholesterol (LDL-C) and glycated hemoglobin, were higher in hypertriglyceridemia episodes of PDRP at baseline. The bacterial classification was different between elevated triglyceride group and normal triglyceride group. Adjusted for age, duration of dialysis, residual renal function, diabetes, thrombocytes, hs-CRP, serum albumin, cholesterol, HDL-C, LDL-C, intact parathyroid hormone (iPTH), glycated hemoglobin and spectrum of bacteria, hypertriglyceridemia were associated significantly with treatment failure of PDRP in our study (OR 3.416, 95% CI 1.223-9.540 p < 0.05).

CONCLUSION

Hypertriglyceridemia at baseline was an independent risk factor for treatment failure of PDRP.

Risk factors for peritoneal dialysis withdrawal due to peritoneal dialysis-related peritonitis

BACKGROUND

Peritoneal dialysis has become commonly used for renal replacement therapy; however, some patients withdraw from peritoneal dialysis due to complications, including peritoneal dialysis-related peritonitis, resulting in the low number of patients on peritoneal dialysis. Risk factors for peritoneal dialysis withdrawal due to peritoneal dialysis-related peritonitis are less certain. This retrospective study aimed to investigate these risk factors.

METHODS

We retrospectively analyzed clinical characteristics, laboratory data, and causative microorganisms of 204 episodes of peritoneal dialysis-related peritonitis between 2007 and 2018 at our institution.

RESULTS

Of the 204 episodes, 38 resulted in withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis. The number of peritonitis episodes per patient-year and the incidence of cardiovascular disease were significantly higher in the withdrawal group. Similarly, this group had low levels of serum creatinine, urea nitrogen, serum albumin, alanine aminotransferase, cholinesterase and high C-reactive protein, and second dialysate cell counts after antibiotic administration. Multivariate logistic regression analysis revealed that serum albumin (odds ratio: 0.465; 95% confidence interval: 0.249-0.868; P=0.016) and cardiovascular disease (odds ratio: 2.508; 95% confidence interval: 1.184-5.315; P=0.016) exhibited significant differences.

CONCLUSIONS

The results of this study suggest that hypoalbuminemia and the presence of cardiovascular disease were independent risk factors for withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis.