Evolution of Peritoneal Dialysis-Associated Peritonitis: Pathogen, Antibiotic Resistance, and the Impact of Lymphocyte Count on Treatment Outcomes

Purpose

Antibiotic administration leads to alterations in pathogenic organisms and antibiotic resistance, posing a significant risk to peritoneal dialysis patients' health. This study aimed to investigate changes in the cause-specific peritonitis, pathogen profiles, antibiotic resistance, and the prognostic factors among patients with peritoneal dialysis-associated peritonitis (PDAP) at our center.

Patients and Methods

We included 463 PDAP patients who attended Peking University Shenzhen Hospital between 2002 and 2023. We analyzed the effects of empirical treatment regimens with cefazolin and ceftazidime or gentamicin.

Results

From 2002 to 2023, we observed that gram-positive staphylococci emerged as the primary causative agents, while the proportion of gram-negative bacillary, enteric peritonitis, and catheter-associated peritonitis decreased significantly. However, the overall cure rate for PDAP and gram-negative bacillary peritonitis declined significantly from 2014 to 2023. Notably, we observed no increase in antibiotic resistance associated with antibiotic drugs use. In addition, reduced lymphocyte counts due to the prevalence of 2019 coronavirus disease (COVID-19) emerged as an independent risk factor for treatment failure in cases of gram-negative bacillary peritonitis.

Conclusion

We did not observe elevated antibiotic resistance in our center when employing empirical dosing strategies involving cefazolin, ceftazidime, or gentamicin. Additionally, we found that a decrease in lymphocyte count due to the COVID-19 epidemic was a significant risk factor for treatment failure in cases of gram-negative bacillary peritonitis at our center. This study provides a foundation for developing clinical treatment strategies for PDAP.

Changes of antibiotic resistance over time among Escherichia coli peritonitis in Southern China

Escherichia coli (E. coli) is the main cause of Gram-negative bacterial peritonitis among peritoneal dialysis patients. According to the 2016 update of the International Society for Peritoneal Dialysis Peritonitis Recommendations, drug susceptibilities of specific organisms should be regularly monitored. The aim of this study was to examine the evolution of antimicrobial resistance of E. coli peritonitis from 2006 to 2018. Two hundred and fifty-three episodes of E. coli peritonitis were enrolled in our study, corresponding to a rate of 0.024 episodes per patient-year. According to drug sensitivity test results, isolates were most sensitive to carbapenems, followed by cefmetazole, piperacillin/tazobactam, cefotetan and amikacin, with an overall rate of more than 90% in both cohorts. Cefazolin and ciprofloxacin resistance increased significantly from 2006-2011 to 2012-2018. Conversely, cefepime and ceftazidime resistance decreased significantly. The extended-spectrum β-lactamase (ESBL) rate fluctuated from 34.7% in 2006-2011 to 46.8% in 2012-2018. Compared with the ESBL-negative strains, ESBL-producing E. coli were more likely be resistant to ampicillin, ampicillin/sulbactam, cephalosporins, quinolones, aminoglycosides, furadantin and sulfamethoxazole and accounted for over 50% of the drug resistance. In the correlation analysis, E. coli displayed significantly increased resistance to cefazolin and ciprofloxacin, a finding correlated with ESBL production (r = 0.883 and 0.276 respectively, p < 0.001 and p = 0.003). In conclusion, the rate of E. coli peritonitis declined stably in recent years, but the resistance to antimicrobial was high.

Peritoneal dialysis-related peritonitis caused by gram-negative organisms: ten-years experience in a single center

Objectives

Concerns are increasing about the clinical characteristics of gram- negative bacterial peritonitis for providing reference for clinical diagnosis, treatment and prevention.

Methods

A retrospective analysis was performed examining patients who developed peritoneal dialysis-related peritonitis (PDRP) from 1 January 2009 to 31 December 2018.

Results

Among 898 PD patients, 677 episodes of peritonitis occurred in 344 patients. Over 10 years, the proportion of gram-negative bacterial peritonitis increased from 0% to 26.15% (p = .045). E. coli was the leading cause (38.51%) of the 148 cases of gram-negative bacterial peritonitis. The increase of E. coli peritonitis between the first 5 and the last 5 years was obvious (20.45% vs. 46.15%). The antimicrobial sensitivity of gram-negative organisms to cefotaxime decreased from 71.43% to 55.84% (p = .017). In the gram-negative group, the effluent white cell count (WCC) on the first day was larger (OR: 1.374;95%CI: 1.248–1.563; p < .001), the time required for the WCC to normalize was longer (OR: 1.100;95%CI: 1.037–1.189; p = .003), and the level of C-reactive protein (CRP) was higher (OR: 1.038;95%CI: 1.026–1.042; p < .001) than those in the gram-positive group. The complete cure rate and treatment failure rate of gram-negative bacteria peritonitis were 87.8% and 12.2% respectively.

Conclusions

Over 10 years, the proportion of gram-negative bacterial peritonitis increased, with E. coli epidermidis being the most common pathogen. More effluent WCC on the first day, longer time required for the WCC to normalize, and higher level of CRP are more common for gram-negative bacterial peritonitis. Prognosis of gram-negative bacterial peritonitis is worse.

Variation in Peritoneal Dialysis-Related Peritonitis Outcomes in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS)

RATIONALE & OBJECTIVE

Peritoneal dialysis (PD)-associated peritonitis is a significant PD-related complication. We describe the likelihood of cure after a peritonitis episode, exploring its association with various patient, peritonitis, and treatment characteristics.

STUDY DESIGN

Observational prospective cohort study.

SETTING & PARTICIPANTS

1,631 peritonitis episodes (1,190 patients, 126 facilities) in Australia, New Zealand, Canada, Japan, Thailand, the United Kingdom, and the United States.

EXPOSURE

Patient characteristics (demographics, patient history, laboratory values), peritonitis characteristics (organism category, concomitant exit-site infection), dialysis center characteristics (use of icodextrin and low glucose degradation product solutions, policies regarding antibiotic self-administration), and peritonitis treatment characteristics (antibiotic used).

OUTCOME

Cure, defined as absence of death, transfer to hemodialysis (HD), PD catheter removal, relapse, or recurrent peritonitis within 50 days of a peritonitis episode.

ANALYTICAL APPROACH

Mixed-effects logistic models.

RESULTS

Overall, 65% of episodes resulted in a cure. Adjusted odds ratios (AOR) for cure were similar across countries (range, 54%-68%), by age, sex, dialysis vintage, and diabetes status. Compared with Gram-positive peritonitis, the odds of cure were lower for Gram-negative (AOR, 0.41 [95% CI, 0.30-0.57]), polymicrobial (AOR, 0.30 [95% CI, 0.20-0.47]), and fungal (AOR, 0.01 [95% CI, 0.00-0.07]) peritonitis. Odds of cure were higher with automated PD versus continuous ambulatory PD (AOR, 1.36 [95% CI, 1.02-1.82]), facility icodextrin use (AOR per 10% greater icodextrin use, 1.06 [95% CI, 1.01-1.12]), empirical aminoglycoside use (AOR, 3.95 [95% CI, 1.23-12.68]), and ciprofloxacin use versus ceftazidime use for Gram-negative peritonitis (AOR, 5.73 [95% CI, 1.07-30.61]). Prior peritonitis episodes (AOR, 0.85 [95% CI, 0.74-0.99]) and concomitant exit-site infection (AOR, 0.41 [95% CI, 0.26-0.64]) were associated with a lower odds of cure.

LIMITATIONS

Sample selection may be biased and generalizability may be limited. Residual confounding and confounding by indication limit inferences. Use of facility-level treatment variables may not capture patient-level treatments.

CONCLUSIONS

Outcomes after peritonitis vary by patient characteristics, peritonitis characteristics, and modifiable peritonitis treatment practices. Differences in the odds of cure across infecting organisms and antibiotic regimens suggest that organism-specific treatment considerations warrant further investigation.

Evaluation of the health and healthcare system burden due to antimicrobial-resistant Escherichia coli infections in humans: a systematic review and meta-analysis

BACKGROUND

Assessment of the burden of disease due to antimicrobial-resistant Escherichia coli infections facilitates understanding the scale of the problem and potential impacts, and comparison to other diseases, which allows prioritization of research, surveillance, and funding. Using systematic review and meta-analysis methodology, the objectives were to evaluate whether humans with antimicrobial-resistant E. coli infections experience increases in measures of health or healthcare system burden when compared to susceptible E. coli infections.

METHODS

Comprehensive literature searches were performed in four primary and seven grey literature databases. Analytic observational studies of human E. coli infections that assessed the impact of resistance to third/fourth/fifth-generation cephalosporins, resistance to quinolones, and/or multidrug resistance on mortality, treatment failure, length of hospital stay and/or healthcare costs were included. Two researchers independently performed screening, data extraction, and risk of bias assessment. When possible, random effect meta-analyses followed by assessment of the confidence in the cumulative evidence were performed for mortality and length of hospital stay outcomes, and narrative syntheses were performed for treatment failure and healthcare costs.

RESULTS

Literature searches identified 14,759 de-duplicated records and 76 articles were included. Based on 30-day and all-cause mortality meta-analyses, regardless of the type of resistance, there was a significant increase in the odds of dying with resistant E. coli infections compared to susceptible infections. A summary mean difference was not presented for total length of hospital stay meta-analyses due to substantial to considerable heterogeneity. Since small numbers of studies contributed to meta-analyses for bacterium-attributable mortality and post-infection length of hospital stay, the summary results should be considered with caution. Studies contributing results for treatment failure and healthcare costs had considerable variability in definitions and reporting.

CONCLUSIONS

Overall, resistant E. coli infections were associated with significant 30-day and all-cause mortality burden. More research and/or improved reporting are necessary to facilitate quantitative syntheses of bacterium-attributable mortality, length of hospital stay, and hospital costs. Protocol Registration PROSPERO CRD42018111197.

Gram-Negative Peritonitis—The Achilles Heel of Peritoneal Dialysis?

Peritonitis caused by gram-negative bacteria is a serious complication of peritoneal dialysis. Antibiotic resistance is common, and response to medical treatment is often poor. In the present article, we review recent advances in the understanding of the pathogenesis and treatment of this serious condition.

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.

Peritonitis in Peritoneal Dialysis Patients in Uruguay

Uruguay is a South American country (3241003 inhabitants) where renal replacement treatment is universally available. The aim of this study was to analyze the incidence and outcome of peritonitis, and the causative organisms and their sensitivity, in order to recommend an empiric initial antibiotic treatment. A retrospective descriptive study of all peritonitis during the period 2004 – 2005 was performed (144 peritonitis, 44% due to gram-positive bacteria). We conclude that the high prevalence of methicillin-resistant coagulase-negative staphylococci justifies the use of vancomycin in the national empiric initial antibiotic protocols.

Continuous ambulatory peritoneal dialysis peritonitis: Microbiology and outcomes

Context

Continuous ambulatory peritoneal dialysis (CAPD) is now a preferred mode of the treatment in patients with end-stage renal disease, but peritonitis remains to be a shortcoming of CAPD. High-culture negativity, emerging drug resistance and peritoneal dialysis (PD)-related morbidity and mortality have been a challenge to tackle.

Aims

The present study was taken up to compare the the various culture methods and to identify the spectrum of organisms causing CAPD peritonitis and their outcome.

Settings and Design

A prospective, observational, cross-sectional study was conducted at a tertiary care teaching hospital in Hyderabad over a period of 1 year.

Subjects and Methods

Dialysate fluid from 100 episodes of clinically suspected peritonitis in 75 patients was processed by conventional centrifuging, water lysis, direct inoculation and addition of centrifuged pellet into brain-heart infusion broth and by automated blood culture system. Identification and antibiotic susceptibility of organisms was done, and the outcome of PD-related peritonitis was analysed.

Statistical Analysis Used

The categorical data and continuous data were analysed using the Chi-square test and Student's t-test, respectively. P < 0.05 was considered statistically significant.

Results

Of the 100 PD fluids, 87 were culture positive. Automated blood culture systems detected 87 episodes, whereas conventional centrifuge method detected only 53 episodes (P = 0.00001). Peritonitis due to Gram-negative organisms (62.3%) was higher than that of Gram-positive peritonitis (31.1%) and fungi (6.4%). Nineteen per cent episodes were constituted by relapse (9), refractory (4), recurrent (4) and repeat (2) peritonitis. Outcomes were analysed as recovery (77%), catheter removal (15%) and death (2.6%).

Conclusions

Direct inoculation of peritoneal fluid into automated blood culture bottles increases the positivity rate and also aids in the early detection of CAPD peritonitis, helping reduce morbidity and mortality of PD patients.

Characterization of Escherichia coli obtained from patients undergoing peritoneal dialysis and diagnosed with peritonitis in a Brazilian centre

Purpose. This study aimed to characterize 27 Escherichia coli isolates obtained from peritoneal dialysis (PD)-related peritonitis that occurred at the University Hospital of Botucatu Medical School, Brazil, between 1997 and 2015.Methodology. These isolates were characterized regarding the occurrence of 22 virulence factor-encoding genes, antimicrobial resistance and biofilm production. We then evaluated whether these factors influenced the clinical outcome.Results. Over an 18-year period, 726 episodes of PD-related peritonitis were diagnosed, with 27 of them (3.7 %) being due to E. coli. The majority of the isolates were classified in phylogroups B1 (33.3 %), B2 (30.0 %) or F (18.0 %). fimH (100.0 %), ompT (66.7 %) and irp2 (51.9 %) were the most prevalent genes, while papA, papC, iha, sat, irp2, iucD, ireA, ibe10, ompT and kpsMTII were significantly more prevalent among isolates belonging to phylogroups B2 and F (P<0.05). Non-susceptibility to quinolones was detected in six isolates, which harboured chromosomal and/or plasmid-mediated quinolone resistance determinants, while two CTX-M extended-spectrum β-lactamase-producing E. coli were identified. Virulence factor-encoding genes (alone or in combination) and antimicrobial resistance were not associated with non-resolution outcomes. However, there was a trend for the ability to produce biofilm to be associated with treatment failure, although this association was not statistically significant.Conclusion. The E. coli isolates were heterogeneous in terms of the features investigated, and were susceptible to most of the antimicrobial drugs tested, despite the unsuccessful treatment observed in more than 50.0 % of the patients. Studies including more cases could help to clarify if biofilm production can influence the outcome in patients with PD-related peritonitis.

Viridans streptococcus peritonitis in peritoneal dialysis: clinical characteristics and comparison with concurrent polymicrobial infection

Background

The clinical course of Viridans streptococci (VS) peritonitis in patients undergoing peritoneal dialysis (PD) is rarely reported. This study examined the association of clinical factors with VS peritonitis.

Methods

We retrospectively reviewed clinical data from patients with VS peritonitis from March 1990 to February 2016 in a PD center in Taiwan and evaluated clinical profiles and treatment outcomes.

Results

A total of 109 episodes of VS peritonitis in 71 patients identified. Among these patients, 57 had mono-VS peritonitis and 14 had concurrent polymicrobial infections. The median time interval from PD initiation to the first VS peritonitis episode was 18 months (range, 0.6–144 months). Among clinical outcomes, most VS peritonitis episodes were completely cured regardless of a history of peritonitis. All episodes with catheter removal occurred in those without a history of recent antibiotic use.

Conclusion

VS peritonitis in patients undergoing PD typically has favorable treatment outcomes. Antibiotic therapy should be started promptly.

Comprehensive Approach to Peritoneal Dialysis-Related Peritonitis by Enteric Microorganisms. Comparison Between Single Organism and Polymicrobial Infections

BACKGROUND

Peritoneal infections of enteric origin (EntP) have been classically investigated using partial strategies, focused on particular subgroups of microorganisms. A more comprehensive approach may facilitate the definition of the nomenclature and clinical presentation of these infections.

OBJECTIVES

To investigate the clinical presentation and outcomes of a full spectrum of EntP, with a particular interest in the comparison between single-organism and polymicrobial infections.

METHOD

Following an observational design, we investigated 165 single-organism and 83 polymicrobial peritonitis episodes with isolation of at least 1 enteric bacteria (Enterobacteriaceae, Enterococcus spp. and/or intestinal anaerobics). We compared the risk of treatment failure for these 2 types of infection and explored the significance of the isolation of specific microorganisms and of their antibacterial susceptibility patterns.

RESULTS

Polymicrobial EntP was associated with higher rates of hospitalization, more changes to initial antibiotic therapy, more surgical explorations, and higher mortality and treatment failure rates than monobacterial EntP. However, stratified and multivariate analyses revealed that the burden of these differences rested on the isolation of intestinal anaerobics (odds ratio [OR] 12.05, 95% confidence interval [CI] 2.53-31.09, p < 0.001) and/or Enterococcus faecium (OR 3.37, 95% CI 1.02-11.30, p = 0.046), while other polymicrobial infections were more comparable with single-organism peritonitis, except for even higher mortality rates in the former group. Lower antibiotic susceptibility of the isolations (OR 1.18, 95% CI 0.51-2.70, p = 0.70) did not perform as a predictor of treatment failure.

CONCLUSION

A comprehensive approach to peritoneal infections by intestinal microorganisms may provide a focused perspective of the clinical presentation and outcomes of these complications of peritoneal dialysis.

Impact of infection with extended-spectrum β-lactamase-producing Escherichia coli or Klebsiella species on outcome and hospitalization costs

BACKGROUND

Extended-spectrum β-lactamase (ESBL)-producing bacteria are important sources of infection; however, Canadian data evaluating the impact of ESBL-associated infection are lacking.

AIM

To determine whether patients infected with ESBL-producing Escherichia coli or Klebsiella species (ESBL-EcKs) exhibit differences in clinical outcome, microbiological outcome, mortality, and/or hospital resource use compared to patients infected with non-ESBL-producing strains.

METHODS

A retrospective case-control study of 75 case patients with ESBL-EcKs matched to controls infected with non-ESBL-EcKs who were hospitalized from June 2010 to April 2013 was conducted. Patient-level cost data were provided by the institution's business office. Clinical data were collected using the electronic databases and paper charts.

FINDINGS

Median infection-related hospitalization costs per patient were greater for cases than controls (C$10,507 vs C$7,882; median difference: C$3,416; P = 0.04). The primary driver of increased costs was prolonged infection-related hospital length of stay (8 vs 6 days; P = 0.02) with patient location (ward, ICU) and indirect care costs (including costs associated with infection prevention and control) as the leading cost categories. Cases were more likely to experience clinical failure (25% vs 11%; P = 0.03), with a higher all-cause mortality (17% vs 5%; P = 0.04). Less than half of case patients were prescribed appropriate empiric antimicrobial therapy, whereas controls received adequate initial treatment in nearly all circumstances (48% vs 96%; P < 0.01).

CONCLUSION

Patients with infection caused by ESBL-EcKs are at increased risk for clinical failure and mortality, with additional cost to the Canadian healthcare system of C$3,416 per patient.

Microbiological Surveillance of Peritoneal Dialysis Associated Peritonitis: Antimicrobial Susceptibility Profiles of a Referral Center in GERMANY over 32 Years

Objectives

Peritonitis is one of the most important causes of treatment failure in peritoneal dialysis (PD) patients. This study describes changes in characteristics of causative organisms in PD-related peritonitis and antimicrobial susceptibility.

Methods

In this single center study we analyzed retrospective 487 susceptibility profiles of the peritoneal fluid cultures of 351 adult patients with peritonitis from 1979 to 2014 (divided into three time periods, P1-P3).

Results

Staphylococcus aureus decreased from P1 compared to P2 and P3 (P<0.05 and P<0.01, respectively). Methicillin-resistant S. aureus (MRSA) occurred only in P3. Methicillin-resistant Staphylococcus epidermidis (MRSE) increased in P3 over P1 and P2 (P <0.0001, respectively). In P2 and P3, vancomycin resistant enterococci were detected. The percentage of gram-negative organisms remained unchanged. Third generation cephalosporin resistant gram-negative rods (3GCR-GN) were found exclusively in P3. Cefazolin-susceptible gram-positive organisms decreased over the three decades (93% in P1, 75% in P2 and 58% in P3, P<0.01, P<0.05 and P<0.0001, respectively). Vancomycin susceptibility decreased and gentamicin susceptibility in gram-negatives was 94% in P1, 82% in P2 and 90% in P3. Ceftazidim susceptibility was 84% in P2 and 93% in P3.

Conclusions

Peritonitis caused by MSSA decreased, but peritonitis caused by MRSE increased. MRSA peritonitis is still rare. Peritonitis caused by 3GCR-GN is increasing. An initial antibiotic treatment protocol should be adopted for PD patients to provide continuous surveillance.

Escherichia coli Peritonitis in peritoneal dialysis: the prevalence, antibiotic resistance and clinical outcomes in a South China dialysis center

INTRODUCTION

Escherichia coli (E. coli) peritonitis is a frequent, serious complication of peritoneal dialysis (PD). The extended-spectrum β-lactamase (ESBL)-producing E. coli peritonitis is associated with poorer prognosis and its incidence has been on continuous increase during the last decades. However, the clinical course and outcomes of E. coli peritonitis remain largely unclear.

METHODS

All of the E. coli peritonitis episodes that occurred in our dialysis unit from 2006 to 2011 were reviewed. The polymicrobial episodes were excluded.

RESULTS

In total, ninety episodes of monomicrobial E. coli peritonitis occurred in 68 individuals, corresponding to a rate of 0.027 episodes per patient-year. E. coli was the leading cause (59.2%) of monomicrobial gram-negative peritonitis. ESBL-producing strains accounted for 35.5% of E. coli peritonitis. The complete cure rate and treatment failure rate of E. coli peritonitis were 77.8% and 10.0% respectively. Patients with preceding peritonitis had a higher risk of ESBL production as compared to those without peritonitis history [odds ratio (OR): 5.286; 95% confidence interval (CI): 2.018 - 13.843; p = 0.001]. The risk of treatment failure was significantly increased when the patient had a baseline score of Charlson Comorbidity Index (CCI) above 3 (OR: 6.155; 95% CI: 1.198 - 31.612; p = 0.03), or had diabetes mellitus (OR: 8.457; 95% CI: 1.838 - 38.91; p = 0.006), or hypoalbuminemia (≤ 30g/l) on admission (OR: 13.714; 95% CI: 1.602 - 117.428; p = 0.01). Prolonging the treatment course from 2 to 3 weeks or more reduced the risk of relapse and repeat significantly (p < 0.05).

CONCLUSIONS

E. coli peritonitis remains a common complication of PD. The clinical outcomes of E. coli peritonitis are relatively favorable despite the high ESBL rate. A history of peritonitis is associated with increased risk for ESBL development. The severity of baseline comorbidities, the presence of diabetes mellitus and hypoalbuminemia at admission are associated with poor outcomes.

Lipopolysaccharide (LPS)-induced autophagy is involved in the restriction of Escherichia coli in peritoneal mesothelial cells

BACKGROUND

Host cell autophagy is implicated in the control of intracellular pathogen. Escherichia coli (E.coli) is the most common organism caused single-germ enterobacterial peritonitis during peritoneal dialysis. In this study, we investigated autophagy of peritoneal mesothelial cells and its role in defense against E.coli.

RESULTS

Autophagy in human peritoneal mesothelial cell line (HMrSV5) was induced by lipopolysaccharide (LPS) in a dose-dependent and time-dependent way, which was demonstrated by increased expression of Beclin-1 and light chain 3 (LC3)-II, the accumulation of punctate green fluorescent protein-LC3, and a higher number of monodansylcadaverine-labeled autophagic vacuoles. After incubation of HMrSV5 cells with E.coli following LPS stimulation, both the intracellular bactericidal activity and the co-localization of E.coli (K12-strain) with autophagosomes were enhanced. Conversely, blockade of autophagy with 3-methyladenine, wortmannin or Beclin-1 small-interfering RNA (siRNA) led to a significant reduction in autophagy-associated protein expression, attenuation of intracellular bactericidal activity, and reduced co-localization of E.coli with monodansylcadaverine-labeled autophagosomes. In addition, treatment of HMrSV5 cells with LPS caused a dose-dependent and time-dependent increase in Toll-like receptor 4 (TLR4) expression. Both knockdown of TLR4 with siRNA and pharmacological inhibition of TLR4 with Polymyxin B significantly decreased LPS-induced autophagy. Furthermore, TLR4 siRNA attenuated remarkably LPS-induced intracellular bactericidal activity.

CONCLUSIONS

Our findings demonstrated for the first time that LPS-induced autophagy in peritoneal mesothelial cells could enhance the intracellular bactericidal activity and the co-localization of E.coli with autophagosomes. The activation of TLR4 signaling was involved in this process. These results indicate that LPS-induced autophagy may be a cell-autonomous defense mechanism triggered in peritoneal mesothelial cells in response to E.coli infection.

Extended Spectrum β-lactamase–producing &lt;italic&gt;E. coli&lt;/italic&gt;-related Nosocomial Peritonitis Treated Successfully with Meropenem in a Patient on Peritoneal Dialysis

Peritonitis is a common and potentially serious infection in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The most common organisms usually associated with CAPD peritonitis are <italic>Staphylococcus aureus</italic> and <italic>Staphylococcus epidermidis</italic>. Rarely, aerobic gram negative bacilli have been the causative agents of CAPD peritonitis. The treatment of CAPD peritonitis requires removal of the peritoneal catheter and treatment with parenteral antibiotics active against the causative pathogen. While hospitalized for CAPD peritonitis, a 55-year-old man on CAPD had nosocomial peritonitis secondary to infection by ESBL–producing <italic>E. coli</italic>, that was sensitive to imipenem and meropenem. He was treated successfully with a 4-week course of intraperitoneal meropenem therapy without subsequent relapse, loss of peritoneal catheter, ultrafiltration failure, or dialysis inadequacy.

Infectious complications in dialysis--epidemiology and outcomes

This Review focuses on the changing epidemiology of infections among patients with end-stage renal disease who are undergoing dialysis. In particular, bloodstream infections related to vascular access in patients undergoing hemodialysis, and peritonitis in patients undergoing peritoneal dialysis, are highlighted. Gram-positive (staphylococcal and enterococcal) bloodstream infections and Gram-negative peritonitis (especially extended-spectrum β-lactamase-producing organisms) contribute substantially to excess health-care use owing to infection caused by dialysis access. Although the management of peritoneal-dialysis-related peritonitis has been hampered by a dearth of randomized, controlled studies, epidemiological data have provided useful information. To overcome the problem of differing methods used to monitor infections within various dialysis centers, uniform reporting systems for vascular-access-related infection and peritoneal-dialysis-related peritonitis, as recommended by the Centers for Disease Control and Prevention and the International Society for Peritoneal Dialysis, respectively, are discussed. Infections unrelated to the port of entry for dialysis are also examined, namely hepatitis and respiratory infection. To address the disease burden, we examine the infection-related mortality as well as the implications for subsequent cardiovascular mortality.

Clinical course and outcomes of single-organism Enterococcus peritonitis in peritoneal dialysis patients

BACKGROUND AND OBJECTIVES

Enterococci are part of the normal flora of the gastrointestinal tract. They can cause enteric peritonitis, which is a serious complication of peritoneal dialysis (PD). However, the clinical course and outcome of PD-related Enterococcus peritonitis remains unclear.

METHODS

We reviewed all Enterococcus peritonitis episodes occurring in our dialysis unit from 1995 to 2009.

RESULTS

During the study period, 1421 episodes of peritonitis were recorded. Of 29 episodes (2.0%) that were attributable to single-organism Enterococcus, 12 episodes were caused by E. faecalis; 9, by E. faecium; and the remaining 8, by other Enterococcus species. The overall rate of ampicillin resistance was 41.4%. Recent use of antibiotics was associated with the development of ampicillin-resistant Enterococcus (ARE) peritonitis (hazard ratio: 12.53; p = 0.04). The primary response rate of Enterococcus peritonitis was significantly higher than that of Escherichia coli peritonitis (89.7% vs. 69.9%, p = 0.038), but the primary response rate was not significantly lower for ARE peritonitis than for ampicillin-susceptible Enterococcus (ASE) peritonitis (83.3% vs. 94.1%, p = 0.553). However, significantly more patients with ARE had received vancomycin (83.3% vs. 23.5%, p = 0.003), with a longer mean duration of vancomycin treatment (11.8 ± 6.9 days vs. 3.7 ± 6.8 days, p = 0.005).

CONCLUSIONS

Recent use of antibiotics was a risk factor for the development of ARE peritonitis. Outcomes in ASE and ARE peritonitis were similar, but vancomycin was required during treatment for ARE peritonitis, in turn possibly predisposing the patients to infections caused by vancomycin-resistant organisms.

Positive dialysate gram stain predicts outcome of empirical antibiotic therapy for peritoneal dialysis-associated peritonitis

Empirical antibiotic treatment with a first-generation cephalosporin plus gentamicin for peritoneal dialysis (PD)-associated peritonitis before culture results are available is still wildly used due to concerns regarding the economic burden and antibiotic-resistant bacterial infections. The aim of this study is to define the factors that predict the outcome of empirical antibiotic therapy for PD peritonitis. This is a retrospective study of patients with PD peritonitis over the last 10 years. Patients who had been treated empirically with intermittent intraperitoneal first-generation cephalosporin and gentamicin were enrolled. Eighty-three patients had 192 episodes of PD peritonitis. In total, 159 peritonitis episodes were treated with intraperitoneal antibiotics combined with first-generation cephalosporin and gentamicin empirically. Twenty-five peritonitis episodes had no pathogens identified by dialysate culture. In total, 122 (122/159, 76.7%) PD peritonitis episodes were caused by bacteria, 9 (9/159, 5.7%) were fungal, and 3 (3/159, 1.9%) were Mycobacterium tuberculosis peritonitis. Sixty-four (64/159, 40.3%) peritonitis episodes were successfully cured by empirical intraperitoneal antibiotic therapy. Empirical antibiotic treatment failed in 95 episodes (95/159, 59.7%). The positive rates of dialysate Gram stain in the empirical treatment success and failure groups were 15.6% and 40.0%, respectively (P = 0.001). The odds ratio of empirical treatment failure with a positive bacteria Gram stain was 3.60 (95% CI: 1.65-7.82). The dialysate Gram staining result was a significant predictor of empirical antibiotics treatment outcome for PD-associated peritonitis. Therefore, using an empirical antibiotic regimen for patients with an initial positive bacterial Gram stain of the dialysate should be introduced cautiously.

Campylobacter Peritonitis Complicating Continuous Ambulatory Peritoneal Dialysis: Report of Three Cases and Review of the Literature

Background

The micro-organisms involved in continuous ambulatory peritoneal dialysis (CAPD) peritonitis are usually gram-positive cocci of cutaneous origin. Campylobacter species are rarely implicated as a cause of CAPD peritonitis.

Methods

A retrospective review of 100 consecutive episodes of peritonitis was carried out in patients undergoing CAPD or automated PD in our hospital from June 2004 to December 2007. Collection of dialysate and microbial examination was done according to ISPD guidelines. Identification of the organism was made on the basis of Gram smear morphology, positive oxidase test, and biochemical reactions using API Campi (BioMérieux, Marcy l'Étoile, France). Susceptibility testing was performed using E-test (AB Biodisc, Solna, Sweden) and confirmation was done by molecular techniques.

Results

The causative organisms in 23 of these episodes were gram-negative bacteria, 3 of which were identified as Campylobacter species using special culture techniques. The clinical presentation in our patients with Campylobacter peritonitis (CP) was different from that of patients with peritonitis from other organisms in that all 3 had diarrhea at presentation. Among patients with CP, no subspecies-specific feature was identified. Good response to the antibiotic treatment was observed; there was no relapse/recurrence of peritonitis, catheter loss, or death.

Conclusion

Incidence of CP remains low and, regardless of the subtype, clinical outcomes are better than those seen with other gram-negative bacteria such as Pseudomonas. The presence of diarrhea at presentation and the finding of curved or spiral gram-negative bacilli in the Gram smear of peritoneal dialysis effluent should make one think of CP. The use of appropriate microbiology techniques in this situation will increase the isolation of this organism.

Enhanced local production of vascular endothelial growth factor is not sufficient to increase peritoneal permeability to protein during acute peritonitis

Dialysate concentrations of inflammatory mediators and growth factors, such as vascular endothelial growth factor (VEGF), are increased during acute peritonitis in peritoneal dialysis patients; however, it can be difficult to determine whether these high concentrations are caused by either increased peritoneal permeability or enhanced local production within peritoneal tissues. VEGF and total protein kinetics were first compared in a rabbit model during an 8-h dwell of dialysis solution containing 2.5% dextrose with (peritonitis) and without (control) the addition of 1-2 x 10(5) colony forming units (cfus) of Escherichia coli (series 1 experiments). Series 2 experiments determined whether intraperitoneal administration of indomethacin (75 microg/mL) altered the kinetics of VEGF and its local production during peritonitis. Series 1 experiments showed that peritonitis resulted in increased peritoneal permeability to total protein, enhanced appearance of VEGF in the dialysate, and increased tissue VEGF mRNA expression in the cecum and abdominal muscle tissues. Series 2 experiments showed that intraperitoneal administration of indomethacin during peritonitis blocked the increase in peritoneal permeability to total protein but had no effect on the appearance rate of VEGF in the dialysate. Intraperitoneal indomethacin decreased tissue VEGF mRNA expression in the cecum but not in the diaphragm or abdominal muscle tissues. It is concluded that the enhanced appearance of VEGF in peritoneal dialysate during peritonitis is largely from increased local production within peritoneal tissues. These observations also demonstrate that enhanced local production of VEGF is not sufficient to increase peritoneal permeability to total protein during peritonitis.

Non-Pseudomonas Gram-negative peritonitis

Non-Pseudomonas Gram-negative organisms account for over 10% of cases of peritoneal dialysis-associated peritonitis. The key findings from a paper by Szeto et al. are discussed and compared with those from previous publications. This type of peritonitis has a high rate of catheter removal and technique failure. Results may be better with more aggressive antibiotic treatment. Other developments in the field are reviewed.