Clinical Pharmacokinetics of Gentamicin in Various Patient Populations and Consequences for Optimal Dosing for Gram-Negative Infections: An Updated Review

Gentamicin is an aminoglycoside antibiotic with a small therapeutic window that is currently used primarily as part of short-term empirical combination therapy. Gentamicin dosing schemes still need refinement, especially for subpopulations where pharmacokinetics can differ from pharmacokinetics in the general adult population: obese patients, critically ill patients, paediatric patients, neonates, elderly patients and patients on dialysis. This review summarizes the clinical pharmacokinetics of gentamicin in these patient populations and the consequences for optimal dosing of gentamicin for infections caused by Gram-negative bacteria, highlighting new insights from the last 10 years. In this period, several new population pharmacokinetic studies have focused on these subpopulations, providing insights into the typical values of the most relevant pharmacokinetic parameters, the variability of these parameters and possible explanations for this variability, although unexplained variability often remains high. Both dosing schemes and pharmacokinetic/pharmacodynamic (PK/PD) targets varied widely between these studies. A gentamicin starting dose of 7 mg/kg based on total body weight (or on adjusted body weight in obese patients) appears to be the optimal strategy for increasing the probability of target attainment (PTA) after the first administration for the most commonly used PK/PD targets in adults and children older than 1 month, including critically ill patients. However, evidence that increasing the PTA results in higher efficacy is lacking; no studies were identified that show a correlation between estimated or predicted PK/PD target attainment and clinical success. Although it is unclear if performing therapeutic drug monitoring (TDM) for optimization of the PTA is of clinical value, it is recommended in patients with highly variable pharmacokinetics, including patients from all subpopulations that are critically ill (such as elderly, children and neonates) and patients on intermittent haemodialysis. In addition, TDM for optimization of the dosing interval, targeting a trough concentration of at least < 2 mg/L but preferably < 0.5–1 mg/L, has proven to reduce nephrotoxicity and is therefore recommended in all patients receiving more than one dose of gentamicin. The usefulness of the daily area under the plasma concentration–time curve for predicting nephrotoxicity should be further investigated. Additionally, more research is needed on the optimal PK/PD targets for efficacy in the clinical situations in which gentamicin is currently used, that is, as monotherapy for urinary tract infections or as part of short-term combination therapy.

Anti-infective Medicines Use in Children and Neonates With Pre-existing Kidney Dysfunction: A Systematic Review

Background

Dosing recommendations for anti-infective medicines in children with pre-existing kidney dysfunction are derived from adult pharmacokinetics studies and adjusted to kidney function. Due to neonatal/pediatric age and kidney impairment, modifications in renal clearance and drug metabolism make standard anti-infective dosing for children and neonates inappropriate, with a risk of drug toxicity or significant underdosing. The aim of this study was the systematic description of the use of anti-infective medicines in pediatric patients with pre-existing kidney impairment.

Methods

A systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The EMBASE, Medline and Cochrane databases were searched on September 21st, 2021. Studies in all languages reporting data on pre-defined outcomes (pharmacokinetics-PK, kidney function, safety and efficacy) regarding the administration of anti-infective drugs in children up to 18 years with pre-existing kidney dysfunction were included.

Results

29 of 1,792 articles were eligible for inclusion. There were 13 case reports, six retrospective studies, nine prospective studies and one randomized controlled trial (RCT), reporting data on 2,168 pediatric patients. The most represented anti-infective class was glycopeptides, with seven studies on vancomycin, followed by carbapenems, with five studies, mostly on meropenem. Antivirals, aminoglycosides and antifungals counted three articles, followed by combined antibiotic therapy, cephalosporins, lipopeptides with two studies, respectively. Penicillins and polymixins counted one study each. Nine studies reported data on patients with a decreased kidney function, while 20 studies included data on kidney replacement therapy (KRT). Twenty-one studies reported data on PK. In 23 studies, clinical outcomes were reported. Clinical cure was achieved in 229/242 patients. There were four cases of underdosing, one case of overdosing and 13 reported deaths.

Conclusion

This is the first systematic review providing evidence of the use of anti-infective medicines in pediatric patients with impaired kidney function or requiring KRT. Dosing size or interval adjustments in pediatric patients with kidney impairment vary according to age, critical illness status, decreased kidney function and dialysis type. Our findings underline the relevance of population PK in clinical practice and the need of developing predictive specific models for critical pediatric patients.

ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment

Peritoneal dialysis (PD)-associated peritonitis is a serious complication of PD and prevention and treatment of such is important in reducing patient morbidity and mortality. The ISPD 2022 updated recommendations have revised and clarified definitions for refractory peritonitis, relapsing peritonitis, peritonitis-associated catheter removal, PD-associated haemodialysis transfer, peritonitis-associated death and peritonitis-associated hospitalisation. New peritonitis categories and outcomes including pre-PD peritonitis, enteric peritonitis, catheter-related peritonitis and medical cure are defined. The new targets recommended for overall peritonitis rate should be no more than 0.40 episodes per year at risk and the percentage of patients free of peritonitis per unit time should be targeted at >80% per year. Revised recommendations regarding management of contamination of PD systems, antibiotic prophylaxis for invasive procedures and PD training and reassessment are included. New recommendations regarding management of modifiable peritonitis risk factors like domestic pets, hypokalaemia and histamine-2 receptor antagonists are highlighted. Updated recommendations regarding empirical antibiotic selection and dosage of antibiotics and also treatment of peritonitis due to specific microorganisms are made with new recommendation regarding adjunctive oral N-acetylcysteine therapy for mitigating aminoglycoside ototoxicity. Areas for future research in prevention and treatment of PD-related peritonitis are suggested.

The impact of intraperitoneal antibiotic administration in patients with peritoneal dialysis-related peritonitis: systematic review and meta-analysis

Background

Peritonitis is a common and clinically important complication in patients receiving peritoneal dialysis (PD). Antibiotic administration is essential for PD-related peritonitis, but routes of administration have not been established enough. Here, we performed a systematic review to assess the efficacy and safety of intraperitoneal (IP) antibiotic administration compared to intravenous (IV) antibiotic administration in patients with PD-related peritonitis.

Methods

Cochrane CENTRAL, MEDLINE, and Ichushi-Web were searched in June 2017. Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed, and articles were screened by four independent reviewers.

Results

Two randomized controlled trials (113 patients) were identified. IP antibiotic administration was more effective than IV antibiotic administration. The pooled risk difference between IP and IV was 0.13 (95% CI − 0.17 to 0.43). Safety assessment indicated less frequency of side effects in patients receiving IP antibiotic administration. The pooled risk ratios of IV to IP regarding adverse drug reaction-related and administration route-related side effects were 5.13 (0.63 to 41.59) and 3.00 (0.14 to 65.90), respectively.

Conclusion

The systematic review and meta-analysis suggested that IP antibiotic administration is more effective and safer in patients with PD-related peritonitis compared to IV antibiotic administration.

The Diagnostic Value of Gram Stain for Initial Identification of the Etiologic Agent of Peritonitis in Capd Patients

Objective

To evaluate the effectiveness of the Gram stain in the initial diagnosis of the etiologic agent of peritonitis in continuous ambulatory peritoneal dialysis (CAPD).

Design

Retrospective study analyzing the sensitivity (S), specificity (SS), positive predictive value (+PV), and negative predictive value (-PV) of the Gram stain relating to the results of cultures in 149 episodes of peritonitis in CAPD. The data were analyzed in two studies. In the first, only the cases with detection of a single agent by Gram stain were taken (Study 1). In the second, only the cases with two agents in Gram stain were evaluated (Study 2).

Setting

Dialysis Unit and Laboratory of Microbiology of a tertiary medical center.

Patients

Sixty-three patients on regular CAPD who presented one or more episodes of peritonitis from May 1992 to May 1995.

Results

The positivity of Gram stain was 93.2% and the sensitivity was 95.7%. The values of S, SS, +PV, and -PV were respectively: 94.9%, 53.5%, 68.3%, and 90.9% for gram -positive cocci and 83.3%, 98.8%, 95.2%, and 95.6% for gram-negative bacilli. The association of grampositive cocci plus gram -negative bacilli were predictive of growth of both in 6.8%, growth of gram -positive cocci in 13.7%, and growth of gram -negative bacilli in 72.5%.

Conclusions

The Gram stain is a method of great value in the initial diagnosis of the etiologic agent of peritonitis in CAPD, especially for gram-negative bacilli.

Pharmacokinetics of Once-Daily Ip Gentamicin in Capd Patients

Objective

This study aimed to investigate the pharmacokinetic characteristics of once-daily intraperitoneal (IP) gentamicin in continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

Prospective, nonrandomized, open study.

Setting

CAPD outpatient clinic in a teaching hospital.

Patients

Ten volunteer CAPD patients without peritonitis.

Interventions

Each patient received a single IP dose of 0.6 mg/kg of gentamicin. Blood and dialysate samples were collected at 0,0.5,1, 2, 3,6 (end of first dwell), and 24 hours after the administration of IP gentamicin. Any urine produced over the 24hour study period was also collected. The dialysate concentration/time data were fitted to a monoexponential curve for all patients.

Results

The bioavailability was 56±11% over a six hour dwell. The mean serum elimination half-life (t1/2) was 35.8 hours. The volume of distribution was 0.23±0.08 L/kg. Equilibration of gentamicin across the peritoneal membrane was rapid, with a t½ equilibration of 4.5 hours. The peritoneal clearance was 5.74±1.5 mL/min. Patients with residual renal function had significantly higher systemic gentamicin clearances (7.36±1.46 mL/min) than those of anuric patients (4.76±1.08 mL/min, p < 0.024).

Conclusion

Currently recommended doses of oncedaily IP gentamicin for the treatment of peritonitis may not produce the desired therapeutic serum and dialysate concentrations over 24 hours for effective treatment of peritonitis.

Continuous Peritoneal Dialysis-Associated Peritonitis of Nosocomial Origin

Objective

To describe our experience with nosocomial continuous peritoneal dialysis (CPD)-associated peritonitis focusing on the incidence, possible risk factors, spectrum of organisms, and outcome.

Design

Retrospective review of the medical records of our CPD patients admitted to an acute-care hospital between November, 1993 and December, 1994.

Setting

University-associated acute-care hospitals in New Haven, Connecticut.

Patients

One hundred and eighty-eight patients maintained on CPD therapy and admitted to an acute-care hospital.

Results

Nineteen patients (5%) developing nosocomial peritonitis (NP) were identified from the 408 admissions occurring during the study period. Patients developing NP were older than the hospitalized CPD patients not developing NP(65.5± 14.6vs58.4± 14.7years, p<0.05). Comorbid diseases including diabetes, peripheral vascular disease, gastrointestinal disease, cardiovascular disease, and human immunodeficiency virus seropositivity were not more common in the patients developing NP. Patients developing NP were hospitalized significantly longer than the CPD patients not developing NP (39.5 ± 46.5 days vs 12.7 ± 12.4 days, p < 0.001). The mean serum albumin was lower in the NP patients than in the CPD patients not developing NP (2.35 ± 0.52 g/dL vs 3.02 ± 0.60 g/dL, p < 0.001). Antecedent antibiotic use and performance of invasive procedures were noted in 89% and 68% of the patients developing NP, respectively. Staphylococcal species, enterococcal species, and gram-negative organisms accounted for 26%, 21 %, and 53% of the episodes of NP, respectively. Furthermore, two strains of Enterococcus resistant to vancomycin were cultured. Eight patients developing NP expired, 8 patients continued CPD therapy, 2 patients transferred to hemodialysis, and one patient recovered renal function.

Conclusion

We conclude that NP is uncommon. Increased age, increased length of hospital stay, and hypoalbuminemia may predispose patients to the development of NP. Further studies with case controls should help to clarify whether antecedent antibiotics or prior performance of invasive procedures predispose patients to the development of nosocomial peritonitis. The spectrum of organisms accounting for NP is different than the spectrum of organisms causing community-acquired CPD-associated peritonitis. Some of these organisms may be resistant to standard antibiotic therapies. Patients developing NP do poorly, with 42% expiring while being treated for NP.

Chronic Peritoneal Dialysis: Seven-Year Experience in a Large Hispanic Program

Objective

To analyze the clinical results of our patient population on continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) in relation to treatment modality systems, compliance, rehabilitation characteristics, complications, and survivals.

Design

The medical records of all patients trained on CAPD or CCPD between 1985 and 1992 were reviewed for the above-mentioned outcome objectives.

Setting

Outpatient CAPD facility affiliated to a tertiary care community hospital.

Patients

The total of 305 patients trained during the study period were studied.

Main Outcome Measures

The patients were studied for age, sex, primary renal disease, peritoneal dialysis modality, need of assistance from a partner during the dialysis procedure, causes of transfer and hospitalization, peritonitis, rehabilitation, patient compliance, and outcome including mortality.

Results

Patient population: 179 (58.7%) males and 126 (41.3%) females, aged 1-80 years(mean47.2±15.09) with a total observation time of 15753 patient-months. The most common diagnosis of the renal disease was diabetic nephropathy (41%). Peritonitis was the main cause of hospitalizations(36.7%) and of transfers (69.5%). Patient survival at one, two, and three years was 87.9%, 76.6%, and 67.0%, respectively. Likewise, technique survival was 65.5%,45.5%, and 30.6%. Peritonitis rate for CAPD has improved from 1.9 episodes per patient-year to 1.2 episodes per patient-year and an overall rate of 1.5 episodes per patient-year.

Conclusions

The experience in a large Hispanic program shows a good patient survival rate. Although there is a trend to a lower peritonitis rate, this continues to be the main cause of transfer, hospitalization, and one of the main causes of death.

Abdominal Catastrophe: Visceral Injury as a Cause of Peritonitis in Patients Treated by Peritoneal Dialysis

Objective

Peritonitis is considered an acceptable and controllable risk in patients undergoing chronic peritoneal dialysis (PD). In contrast, peritonitis due to visceralleakage represents a true “abdominal catastrophe” because of striking morbidity and mortality. To delineate the incidence, causes, and outcomes of catastrophic peritonitis, we compared patients who developed peritonitis due to documented visceral leakage with patients who developed peritonitis due to enteric organisms without evidence of visceral leakage.

Design

Retrospective chart review.

Setting

PD Unit located in tertiary care referral center.

Patients

230 patients treated by PD between January 1988 and June 1996.

Main Outcome Measures

All episodes of PD-related peritonitis occurring over an 8-year period. Hospital course of all patients with or without renal failure who were treated at University Hospitals of Cleveland for ischemic bowel disease, cholecystitis, viscus perforation, or diverticulitis.

Results

Anatomically documented visceral injury caused 32.5% of episodes of enteric bacterial peritonitis in 72 patients between January 1988 and June 1996. The overall incidence of this “abdominal catastrophe” was 11.3%, or 26 of a total of 230 patients treated by PD. Of the 26 patients, 50% died, 30.7% survived but switched permanently to hemodialysis, and only 19.2% remained on, or returned to, PD. Compared to renal failure patients treated by hemodialysis or transplantation and to nonrenal failure patients, the incidence of abdominal catastrophe was 20 -60 times greater in patients treated by PD.

Conclusions

Evidence for injury of an abdominal organ should be sought in all patients treated by PD who develop peritonitis with enteric organisms. Surgical intervention is definitive for diagnosis, and if performed early may reduce morbidity and mortality.

Stability of Drug Additives to Peritoneal Dialysate

Objective

The primary literature was reviewed to determine the stability of drug additives in peritoneal dialysis solutions.

Data Sources

A MEDLINE search and retrieval, covering the period 1981 to 1994, was undertaken to identify relevant original literature. Additional references were identified from citations within the original literature. Non-English literature was excluded unless an English abstract was provided.

Study Selection

Forty-nine studies were identified. Of these, 24 were directly related to drug stability, 13 were related to the clinical use of the drug additives but included no stability data, and 12 examined other, nonstability aspects of in vitroactivity of antibiotics, additives, or drug adsorption in peritoneal dialysis bags and tubing.

Data Extraction

Data included concentrations of drug additives and dialysate solutions, duration and temperatures of storage conditions, types of assay, and whether they were stability-indicating.

Results

Stability was defined as the duration of time that the drug concentration remained at 90% or more of the original concentration. Stability was examined under a large variety of conditions. Thirty-one drugs were identified from 20 manuscripts as single-drug additives. Most beta-Iactams were stable for 1 –2 weeks in a refrigerator and for several days at room temperature. Aminoglycosides were stable for 1 –2 days at room temperature. Glycopeptides were stable for several weeks refrigerated or at room temperature. Prolonged storage at room temperature resulted in instability of cefotaxime, ceftazidime, ceftriaxone, and miconazole. Eleven drugs were identified from seven manuscripts as drug combination studies and showed similar stability as single agents. Dialysate concentration appeared to have minimal effect on stability.

Conclusions

Drug additives in peritoneal dialysate, singly or combined, should be avoided unless data are available to support their stability. Additives should be made as close as possible to the time of the exchange. Alternatively, additives should be stored refrigerated, then warmed prior to use. The practice of preparing numerous bags at one time should be avoided. Finally, stability data do not indicate sterile integrity of the dialysate.

Nystatin Prophylaxis: Its Inability to Prevent Fungal Peritonitis in Patients on Continuous Ambulatory Peritoneal Dialysis

Objective

To evaluate the potential effectiveness of nystatin as prophylaxis for fungal peritonitis (FP) in patients on continuous ambulatory peritoneal dialysis (CAPD).

Design

This historically controlled study was designed to investigate the effectiveness of nystatin in the prevention of FP. For this purpose we compared the incidence of FP among 240 (new and prevalent) CAPD patients between January 1996 and November 1996 (period A) with its incidence in 240 new and prevalent CAPD patients in our program between January 1997 and November 1997 (period B) when nystatin prophylaxis was used. There were 2400 patient-months in each period. Nystatin (500000 IU four times per day), was given orally at the beginning of other antibiotic therapy (usually for peritonitis) and continued for 5 days after the end of the antibiotic therapy.

Results

During period A, 133 peritonitis episodes were recorded, and during period B, 99 episodes were recorded. Six episodes of FP were identified in over 2400 patient months of period A, and 12 in over 2400 patient-months of period B. This difference was not statistically significant. Three episodes of antibiotic-related FP were seen in period A, and four in period B. The remaining episodes arose de novo, that is, unrelated to the use of antibiotics. We observed no side effects for nystatin.

Conclusion

In CAPD patients the use of nystatin, a nonabsorbable antifungal agent, as prophylaxis in every instance of peritonitis or other indications for antibiotics, did not lower the incidence of fungal peritonitis.

Single Daily Dose of Aminoglycosides in the Treatment of Continuous Ambulatory Peritoneal Dialysis Peritonitis

Toxicity of amlnoglycosides is a major concern in the treatment of continuous ambulatory peritoneal dialysis (CAPO) peritonitis. The relatively high blood levels and prolonged and repeated usage may all be contributory. The recognition of the so-called postantibiotic effect, together with the Increased phagocytosis of antiblotictreated cells, may introduce a new mode of therapy with once-dally dosage. Intermittent therapy with vancomycin Is already generally accepted. The extension of this modality to antibiotic therapy is discussed.

Is Heparin Therapy Necessary in Capd Peritonitis?

Objective

Heparin therapy in continuous ambulatory peritoneal dialysis (CAPD) peritonitis seems well established; it is costly due to the necessity of hospitalization. There are no clinical studies that show a benefit of such a treatment. The aim of this study was to investigate whether heparin therapy in CAPD peritonitis isnecessary.

Design and Patients

194 samples of peritoneal dialysates were collected from 17 patients over a period of 24 months. Samples were subdivided into three groups: those without peritonitis (<100 leukocytes/ILL), those with mild peritonitis (100 -499 leukocytes/ILL), and those with severe peritonitis (≥500 leukocytes/ILL).

Measurements

The number of leukocytes per ILL dialysate and total protein concentrations were determined. Furthermore, dialysate concentrations of thrombin-antithrombin 111 (TAT-) complexes (indicator of thrombin formation), D-dimers (indicator of fibrinolysis), and plasminogen activator inhibitor 1 (PAI-1) were measured.

Results

The dialysate protein concentration progressively increased from no peritonitis to mild and severe inflammation. In parallel, dialysate TAT -complex and D-dimer concentrations increased. Thrombin-antithrombin 1I1-complex and D-dimer concentrations correlated strongly in 179 cases (r = 0.76; 62 samples showing peritonitis, 117 samples with no evidence of peritonitis). In the remaining 15 samples of 3 patients, high PAI-1 levels (>40 ng/mL) and low D-dimer concentrations were found. Eleven of the 15 samples showed evidence of peritonitis. In these 11 samples with evidence of peritonitis, high levels of TAT -complexes were detected, while Ddimer concentrations were found to be very low, pointing to a blocked fibrinolysis. The P AI-1levels were not related to leukocyte counts or protein concentrations in the dialysates.

Conclusions

Based on our findings, the routine intraperitoneal administration of heparin in CAPD peritonitis is not necessary. In rare cases an imbalance between coagulation and fibrinolysis due to high PAI-1 levels exists (15 of 194 dialysate samples, 11 of the 15 samples showing peritonitis). These cases -which do require heparinization -can be identified by demonstrating low D-dimer levels in CAPD dialysate at times of peritonitis.

A Survey of CAPD Peritonitis Management and Outcomes in North and South Thames NHS Regions (U.K.): Support for the ISPD Guidelines

Objective

This survey examined the current management of continuous ambulatory peritoneal dialysis (CAPD) peritonitis and the effectiveness of the various antibiotic protocols in use.

Design

The information required was elicited via a postal questionnaire.

Setting

The questionnaire was posted to each renal dialysis unit offering CAPD throughout the North and South Thames National Health Service regions.

Patients

All patients using CAPD at each responding unit were eligible for inclusion.

Main Outcome Measures

Each unit provided details of their CAPD peritonitis episodes for 1997. Each unit's empirical treatment regimen for CAPD peritonitis was sought in addition to response rates. Also requested were numbers for peritonitis episodes, recurrences, and negative cultures, plus the peritonitis rate per patient-month.

Results

Thirteen units returned the questionnaire (87% of the survey population). Nine of the 13 units were using vancomycin regimens, with the remainder using cephalosporin regimens. The results were compared to the audit standards of the British Renal Association. Seventy percent of units reached the 80% mark for response rate; similar results were achieved with both the vancomycin and cephalosporin regimens. Ninety-two percent achieved the suggested peritonitis rate of 1 episode every 18 patient-months; 30% achieved the culture-negative rate of 10%. The average recurrence rate was 19%.

Conclusion

The units contacted achieved most of the standards suggested by the British Renal Association; however, wide variations did exist. Recent guidelines have suggested avoiding vancomycin-based regimens in order to reduce the incidence of vancomycin resistance. The suggested regimen of a cephalosporin with an aminoglycoside seems to represent a suitable alternative.

Pharmacokinetics of Intraperitoneal Cefazolin and Gentamicin in Empiric Therapy of Peritonitis in Continuous Ambulatory Peritoneal Dialysis Patients

Objective

The aim of this study was to measure and evaluate the appropriateness of the actual concentrations of serum and dialysate cefazolin and gentamicin in Thai continuous ambulatory peritoneal dialysis (CAPD) patients treated following the International Society for Peritoneal Dialysis (ISPD) 1996 recommendations for the empiric therapy of CAPD-related peritonitis.

Design

Prospective and descriptive study.

Setting

Institutional level of clinical care.

Patients

CAPD-related peritonitis patients were diagnosed by dialysate effluent white cell count of more than 100/mm3and polymorphonuclear leukocytes of at least 50%. There were 18 patients, all at least 15 years of age, entered; all completed the study.

Intervention

In accordance with the ISPD 1996 recommendations, the antibiotic regimen included continuous intraperitoneal (IP) cefazolin and once-daily IP amino-glycoside. Cefazolin was administered as loading and continuous maintenance doses of 500 and 125 mg/L dialysate, respectively. Gentamicin, 0.6 mg/kg body weight, was given IP once daily. Duration of treatment was 120 hours.

Main Outcome Measures

Serum and dialysate effluent samples of the 18 CAPD patients with peritonitis were measured and used for the synthesis of pharmacokinetic equations that could predict drug concentrations at any treatment time.

Results

Following administration according to the ISPD 1996 treatment recommendations, serum cefazolin reached levels higher than the recommended levels (8 mg/mL) at 3.3 minutes after drug administration, and persisted through the 5-day duration of the study. Dialysate cefazolin levels during the studied period also were persistently higher than the recommended values. The peak serum gentamicin levels were lower than the suggested values of 4 mg/mL, whereas the trough serum gentamicin levels were higher than the minimal toxic concentrations (2 mg/mL). Dialysate gentamicin levels were higher than therapeutic concentrations for only 4.75 hours in each day. It was difficult, using pharmacokinetic studies, to adjust the dosage regimen of gentamicin to achieve appropriately therapeutic levels in both serum and dialysate.

Conclusions

The ISPD 1996 recommended dosage of continuous IP cefazolin could be appropriate for the treatment of CAPD-related peritonitis. Once-daily IP gentamicin administration, however, has less therapeutic benefit and should be re-evaluated.

Changes in Causative Organisms and Their Antimicrobial Susceptibilities in Capd Peritonitis: A Single Center's Experience over one Decade

Background

In recent years, the rate of peritonitis during continuous ambulatory peritoneal dialysis (CAPD) has been significantly reduced. However, peritonitis remains a major complication of CAPD, accounting for considerable mortality and hospitalization among CAPD patients.

Objective

To generate a “center tailored” treatment protocol for CAPD peritonitis by examining the changes of causative organisms and their susceptibilities to antimicrobial agents over the past 10 years.

Method

Retrospective review of the medical records of 1015 CAPD patients (1108 episodes of peritonitis) who were followed up from 1992 through 2001.

Results

The overall incidence of peritonitis was 0.40 episodes/patient-year. The annual rate of peritonitis and the incidence of peritonitis caused by a single gram-positive organism were significantly higher in 1992 and 1993 compared with those in the rest of the years ( p < 0.05). The incidence of peritonitis due to coagulase-negative staphylococcus (CoNS) decreased significantly over time, whereas there was no significant change in the incidence of Staphylococcus aureus (SA)-induced peritonitis. Among CoNS, resistance to methicillin increased from 18.4% in 1992 – 1993 to 41.7% in 2000 – 2001 ( p < 0.05). In contrast, the incidence of methicillin-resistant SA was not different according to the calendar year. Catheter removal rates were significantly higher in peritonitis due to a single gram-negative organism (16.6%) compared with gram-positive peritonitis (4.8%, p < 0.005). The mortality associated with peritonitis was also higher in gram-negative (3.7%) compared with gram-positive peritonitis (1.4%), but there was no statistical significance. Among single gram-positive organism-induced peritonitis, catheter removal rates were significantly higher in SA (9.3%) than those in CoNS (2.9%, p < 0.01) and other gram-positive organisms (2.9%, p < 0.05). In peritonitis caused by CoNS, the methicillin-resistant group showed significantly higher removal rates than the methicillin-susceptible group (8.2% vs 1.0%, p < 0.01).

Conclusion

The incidence of peritonitis for 2001 decreased to less than half that for 1992, due mainly to a significant decrease in CoNS-induced peritonitis, whereas the proportions of peritonitis due to a single gram-negative organism and methicillin-resistant CoNS increased. These findings suggest that it is necessary to prepare new center-based guidelines for the initial empirical treatment of CAPD peritonitis.

Ciprofloxacin and Cefazolin as a Combination for Empirical Initial Therapy of Peritoneal Dialysis-Related Peritonitis: Five-year Follow-up

The treatment of peritoneal dialysis (PD)-related peritonitis has been a matter of extensive investigation, frequently generating therapeutic trials. Several combinations of antibiotics have served as newer protocols and tended to be efficacious, comfortable, and cost-effective. According to the more recent recommendations from the International Society for Peritoneal Dialysis, the rationale for empirical initial therapy of clinically detected peritonitis in PD patients has been to follow the bacterial profile derived from cultured specimens of PD effluents.

The current study describes 5 year's experience with the use of a new antibiotic regimen for the treatment of peritonitis. We herein analyze the outcome of 95 episodes of peritonitis in 54 patients on either automated PD or continuous ambulatory PD at the dialysis unit of the Federal University of Rio de Janeiro. Peritoneal dialysis-related peritonitis was treated with the combination of oral ciprofloxacin and intraperitoneal cefazolin. The observed cure rate was 85.2% and the sensitivity test was observed to be positive for this combination of antibiotics in 88.9% of positive cultures. Of the 14 unsuccessful episodes, 7 were due to catheter colonization and the rest did not respond to the proposed therapy within 48 hours. These 7 cases were also related to peritoneal fluid cultures that were resistant to both ciprofloxacin and cefazolin.

From this study, we propose this combination of oral ciprofloxacin and intraperitoneal cefazolin as a first choice for empirical initial therapy of PD-related peritonitis, given its efficacy and low cost. However, in order to apply the most adequate cost-effective therapy, careful examination of the bacterial profile and sensitivities to antibiotics used in each unit is strongly recommended.

Fungal peritonitis in peritoneal dialysis: a 34-year single centre evaluation

Backgound

Fungal peritonitis (FP) is one of the most important causes of peritoneal dialysis (PD) failure, often burdened by increased morbility and mortality. This study evaluates the clinical course of FP cases that arose between 1983 and 2016 in a single PD unit.

Methods

We conducted a retrospective observational analysis of FP episodes recorded in the Baxter POET (Peritonitis Organism Exit sites Tunnel infections) registry and clinical records. FP incidence rate, PD and patients’ survival and clinical characteristics of the study population were analysed, taking into account the evolution of clinical practice during the study period as a result of technical innovation, scientific evidence and guideline history.

Results

Fourteen FP cases (2.8%) were detected. The overall incidence of PD peritonitis was one episode/27 patient-months. Candida parapsilosis was the most frequently (50%) detected yeast. Seventy-five per cent of cases were considered secondary FP. This group experienced 2.6±1.7 bacterial peritonitis before FP, most frequently due to Staphylococcus and Enterococcus species. Most patients were treated with fluconazole for ≥8 days. All subjects were hospitalized for a median time of 25 days. Tenckhoff catheter removal occurred in all cases of FP and all patients were transferred to haemodialysis. Two patients died. From December 2010 to December 2016, no FP episodes were recorded.

Conclusions

FP is confirmed as a significant cause of PD drop out and increases patients’ mortality risk. Prompt diagnosis of FP, targeted antifugal therapy and rapid PD catheter removal are essential strategies for improved patient and PD survival.

Risk factors for encapsulating peritoneal sclerosis: Analysis of a 36-year experience in a University Hospital

AIM

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication that occurs in peritoneal dialysis (PD) therapy. The present study aimed to identify the risk factors, especially peritonitis and biocompatible PD fluid.

METHODS

The study included 703 patients who received PD between January 1980 and March 2015 at two centres. The patients were divided into two groups: those who had developed EPS (EPS group: n = 44) and those who had no documentary evidence of EPS (non-EPS group: n = 659). The independent risks of EPS were determined by univariate and multivariate logistic models.

RESULTS

Encapsulating peritoneal sclerosis occurred in 44/703 (6.3%) patients between January 1980 and March 2015. In multivariate logistic models of risk factors correlated with EPS, dialysate to plasma creatinine ratio (D/P Cr) by peritoneal equilibration test (PET) and history of peritonitis were risk factors for EPS development (P < 0.01, respectively) in addition to PD duration. Especially, total duration of peritonitis, defined by period between onset and resolution of peritonitis, was an important risk factor for EPS development in patients with a history of peritonitis. Receiver operating characteristic (ROC) curve analysis revealed that cut-off point for EPS development was 36 days. Moreover, biocompatible PD fluid contributed to decreased EPS development.

CONCLUSION

Both the longer duration of peritonitis and higher D/P Cr, as well as the longer PD duration, were risk factors for EPS development. Furthermore, use of biocompatible PD fluid contributed to the decrease in EPS development.

Prevention of Catheter Related Infections in Patients on CAPD

Catheter-related infections remain a serious problem for patients on peritoneal dialysis. Such infections can be reduced by careful patient selection and training, by the use of the best connection technology and screening and treating nasal carriage. To date, treatment is less than optimal and therefore, the primary goal should be prevention of catheter-related infections. Prevention is based on improving catheter design and implantation technique, while providing careful exit-site care. Regardless of how it is implemented, we must aggressively pursue the prevention of catheter-related infections by eradicating S.aureus exit-site carriage in PD patients. Based on its effectiveness in adult PD patients, its low rate of adverse effects, and its reasonable cost-effectiveness, application of mupirocin ointment at the exit-site is the current method of choice for preventing PD catheter infections caused byS. aureus. In addition to reducing S. aureus exit-site infections, mupirocin seems to reduce the rates of staphylococcal peritonitis and PD catheter loss. Whether the ointment should be applied in the nares, to the exit-site or both, and whether it should be used only in staphylococcal nasal carriers or all PD patients requires further study.