Improvement in culture-negative peritoneal dialysis-related peritonitis: a single center's experience

Cefazolin Plus Ceftazidime versus Cefazolin Monotherapy in the Treatment of Culture-Negative Peritonitis: A Retrospective Cohort Study

Background

Based on current ISPD guidelines, it is unclear as to whether ceftazidime should be discontinued in subsequent management of culture-negative peritonitis if it is used as empirical gram-negative coverage. Herein, we aim to compare the clinical outcomes of cefazolin plus ceftazidime versus cefazolin alone.

Methods

This was a retrospective cohort study. Adult peritoneal dialysis (PD) patients who were diagnosed with culture-negative peritonitis between 2014 and 2020 were included. Patients were categorized into two groups according to treatment regimen. Primary response rate, peritonitis relapse rate, and time to primary response were compared. Factors that predicted primary response were determined using Cox regression analysis.

Results

A total of 58 patients were included in the study. Of these, 42 received cefazolin plus ceftazidime and 16 received cefazolin monotherapy. Overall, the mean age was 65.7±10.4 years. Most of the patients (81.3%) were prescribed continuous ambulatory peritoneal dialysis. Initial effluent WBC was 4211±10357 in the combination group and 3833±6931 cell/mm³ in the monotherapy group (p=0.89). There was no significant difference in primary response at day 5 between the two groups (95.2% in the combination group vs93.7% in the monotherapy group, p=0.82). However, cumulative probability of primary response by the Kaplan–Meier analysis in the combination group was higher than in the monotherapy group (p=0.02). Adjusted HR of serum potassium level to predict a primary response was 1.83 according to multivariate analysis (p=0.03). There was no difference between the two groups in terms of peritonitis relapse or catheter removal.

Conclusion

This is the first study to compare clinical outcomes between cefazolin plus ceftazidime versus cefazolin monotherapy in culture-negative peritonitis. Our results suggest that if peritonitis is resolving at day 3, discontinuation of ceftazidime could yield favorable treatment outcomes and might be appropriate for subsequent management. However, the risk of not having gram-negative coverage should be considered.

Peritoneal Effluent Cell-Free DNA Sequencing in Peritoneal Dialysis Patients With and Without Peritonitis

Rationale & Objective

Conventional culture can be insensitive for the detection of rare infections and for the detection of common infections in the setting of recent antibiotic usage. Patients receiving peritoneal dialysis (PD) with suspected peritonitis have a significant proportion of negative conventional cultures. This study examines the utility of metagenomic sequencing of peritoneal effluent cell-free DNA (cfDNA) for evaluating the peritoneal effluent in PD patients with and without peritonitis.

Study Design

Prospective cohort study.

Setting & Participants

We prospectively characterized cfDNA in 68 peritoneal effluent samples obtained from 33 patients receiving PD at a single center from September 2016 to July 2018.

Outcomes

Peritoneal effluent, microbial, and human cfDNA characteristics were evaluated in culture-confirmed peritonitis and culture-negative peritonitis.

Analytical Approach

Descriptive statistics were analyzed and microbial cfDNA was detected in culture-confirmed peritonitis and culture-negative peritonitis.

Results

Metagenomic sequencing of cfDNA was able to detect and identify bacterial, viral, and eukaryotic pathogens in the peritoneal effluent from PD patients with culture-confirmed peritonitis, as well as patients with recent antibiotic usage and in cases of culture-negative peritonitis.

Limitations

Parallel cultures were not obtained in all the peritoneal effluent specimens.

Conclusions

Metagenomic cfDNA sequencing of the peritoneal effluent can identify pathogens in PD patients with peritonitis, including culture-negative peritonitis.

Evaluation of different methods to improve culture-negative peritoneal dialysis-related peritonitis: A single-center study

Background

ISPD recommends culture-negative peritonitis in each peritoneal dialysis (PD) center should less than 15%. The hospital in Thailand, however faced a significantly high rate of culture negative peritonitis, even using blood culture bottles technique. This study evaluates the performance of three different culture methods in detecting organisms in PD related peritonitis.

Methods

A prospective cohort diagnostic study was performed in PD patients diagnosed with PD related peritonitis in Surin Hospital from October 2018 to June 2020. The Diagnosis of peritonitis was followed ISPD guidelines. PDF sample from each patient was processed by three different blood culture bottle-based techniques, including i) 50 ml PDF centrifugation, and ii) 10 ml PDF centrifugation before inoculated into blood culture bottles, and iii) inoculation into blood culture bottles without centrifugation. The sensitivities and isolated organisms were compared among the individual methods.

Results

Of 126 PD patients with clinical peritonitis, PD related peritonitis was diagnosed in 87 patients with 105 PDF analysis. PDF culture showed gram-positive organisms 34%, gram-negative organisms 41%, fungal 5.71%, and culture-negative result in 22.86%. The direct blood culture method was positive in 59.05%, while centrifugation before inoculated into blood culture bottles, has a higher percentage of positive results, 60.95% and 64.76% from 10 ml to 50 ml PDF volume; respectively. The sensitivity was 84% and 76.5% for 50 ml PDF centrifugation and blood culture without centrifugation.

Conclusion

Large volume PDF centrifugation before inoculating into blood culture bottles may improve the positive culture rate in PD related peritonitis.

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PD related peritonitis is the major cause of technical failure in peritoneal dialysis.

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Early diagnosis and prompt antibiotic initiation are vital clues for treatment success in peritoneal dialysis related peritonitis.

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Inappropriate culture techniques is one of the common causes of negative culture results.

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Centrifugation of peritoneal fluid before culture may improve the diagnostic yield.

Multicentre registry data analysis comparing outcomes of culture-negative peritonitis and different subtypes of culture-positive peritonitis in peritoneal dialysis patients

BACKGROUND

The outcomes of culture-negative peritonitis in peritoneal dialysis (PD) patients have been reported to be superior to those of culture-positive peritonitis. The current study aimed to examine whether this observation also applied to different subtypes of culture-positive peritonitis.

METHODS

This multicentre registry study included all episodes of peritonitis in adult PD patients in Australia between 2004 and 2014. The primary outcome was medical cure. Secondary outcomes were catheter removal, hemodialysis transfer, relapsing/recurrent peritonitis and peritonitis-related death. These outcomes were analyzed using mixed effects logistic regression.

RESULTS

Overall, 11,122 episodes of peritonitis occurring in 5367 patients were included. A total of 1760 (16%) episodes were culture-negative, of which 77% were medically cured. Compared with culture-negative peritonitis, the odds of medical cure were lower in peritonitis caused by Staphylococcus aureus (adjusted odds ratio (OR) 0.62, 95% confidence interval (CI) 0.52-0.73), Pseudomonas species (OR 0.20, 95% CI 0.16-0.26), other gram-negative organisms (OR 0.48, 95% CI 0.41-0.56), polymicrobial organisms (OR 0.30, 95% CI 0.25-0.35), fungi (OR 0.02, 95% CI 0.01-0.03), and other organisms (OR 0.61, 95% CI 0.49-0.76), while the odds were similar in other (non-staphylococcal) gram-positive organisms (OR 1.11, 95% CI 0.97-1.28). Similar results were observed for catheter removal and hemodialysis transfer. Compared with culture-negative peritonitis, peritonitis-related mortality was significantly higher in culture-positive peritonitis except that due to other gram-positive organisms. There was no difference in the odds of relapsing/recurrent peritonitis between culture-negative and culture-positive peritonitis.

CONCLUSION

Culture-negative peritonitis had superior outcomes compared to culture-positive peritonitis except for non-staphylococcal gram-positive peritonitis.

Peritoneal Dialysis-Associated Peritonitis: Suggestions for Management and Mistakes to Avoid

Peritonitis is a common complication of peritoneal dialysis that is associated with substantial morbidity and mortality. Peritonitis increases treatment costs and hospitalization events and is the most common reason for transfer to hemodialysis. Although there is much focus on preventing peritoneal dialysis–associated peritonitis, equally as important is appropriate management to minimize the morbidity of a peritonitis episode when it has occurred. Despite the presence of international guidelines on peritonitis treatment, the evidence base to support optimal peritonitis treatment practices is lacking, leaving the practitioner to rely on clinical experience and extrapolate from across other infection treatment practices. This article reviews common mistakes and misconceptions that we have observed in the management of peritonitis that may compromise treatment success. It also provides suggestions on common controversial aspects of peritonitis management based on the best available literature. Although the use of the word mistakes is somewhat controversial and subjective, we acknowledge that evidence is lacking and have based many of our suggestions on clinical judgment, experience, and available data.

Microbacterium Peritonitis in Peritoneal Dialysis: A Case Report and Review

Peritoneal dialysis-related peritonitis (PDRP) is a commonly encountered complication in patients undergoing peritoneal dialysis (PD). Establishing the causative organism in PDRP allows for targeted antibiotic selection, helps to guide duration of therapy, and determines the need for catheter removal. Microbacterium is a genus of aerobic gram-positive bacilli found in the environment. Its detection in clinical isolates has increased owing to improved microbiology diagnostics. We present a case of PDRP due to M. paraoxydans and review the epidemiology, clinical manifestations, and available evidence for treatment of this organism. The high rate of recurrent infection and limited data regarding antimicrobial susceptibility testing pose significant challenges in the management of PDRP caused by Microbacterium species.

Time to Positivity of Bacteria Cultures in Peritoneal Dialysis Fluid: Evaluation of Different Laboratory Techniques

Patients with chronic kidney disease on peritoneal dialysis (PD) are susceptible to infections, with peritonitis being the primary cause of dropout. Peritoneal fluid culture is one of the essential elements for proper diagnosis and peritonitis treatment. The aim of this study was to compare the time required to obtain a positive culture using different laboratory methods. An in vitro cross-sectional study was conducted comparing different techniques for preparation and culture of bacteria in peritoneal fluid. The research was carried out with 21 sterile dialysis bags and 21 PD bags containing peritoneal fluid drained from patients without peritonitis. Fluids from the 42 PD bags were contaminated by injecting a coagulase-negative Staphylococcus suspension and then prepared for culture using 4 distinct techniques: A - direct culture; B - post-centrifugation culture; C - direct culture after 4 h sedimentation; and D - culture after 4 h sedimentation and centrifugation. This was followed by seeding. In the 21 contaminated sterile bags, mean times to obtain a positive culture with techniques D (19.6 h ± 2.6) and C (19.1 h ± 2.3) were longer than with technique A (15.8 h ± 3.0; p < 0.01), but not statistically different from group B (19.0 h ± 3.2). The same occurred in the 21 bags drained from patients, with mean times for techniques D (14.0 h ± 1.9) and C (14.5 h ± 1.7) being longer than technique A (12.22 h ± 1.94; p < 0.05) but not statistically different from technique B (13.2 h ± 1.3). The sedimentation and centrifugation steps seem to be unnecessary and may delay antibiotic sensitivity test results by approximately 8 hours.