Multidrug-resistant organisms in dialysis patients

High frequency of colonization by extended-spectrum beta-lactamase-producing Gram-negative bacilli in hemodialysis patients and their household contacts in Colombia: dissemination between the community and the hospital

OBJECTIVES

Increasing colonization by beta-lactam-resistant Gram-negative bacilli (BR-GNB) represents a risk for infections and bacterial resistance spread, both in hospitals and the community. Hemodialysis patients and their household contacts regularly transit between these environments. This study investigated the clinical and epidemiological characteristics of BR-GNB colonization in hemodialysis patients and their household contacts, as well as the genetic relationship between their isolates.

METHODS

A cross-sectional study was conducted on hemodialysis patients at a hospital-associated dialysis center in Medellín, Colombia and their household contacts. Clinical and epidemiological information was collected. Colonization was assessed from stool or rectal swab samples. Bacterial identification and susceptibility were determined using chromogenic media and Vitek-2. Molecular characterization included beta-lactamase detection by polymerase chain reaction, multiple-locus sequence typing (MLST), pulsed-field gel electrophoresis, and identification of Escherichia coli phylogroups by the Clermont protocol.

RESULTS

This study included 36 hemodialysis patients and 90 household contacts. Colonization by BR-GNB occurred in 58.3% of patients and 22.2% of household contacts. The main beta-lactamase detected was CTX-M group-1 (40.5%). In 3 of the 9 homes that had more than 1 colonized individual, a genetic relationship was found. MLST showed a high diversity in E. coli isolates, and the most frequent phylogroups were B1 and B2.

CONCLUSIONS

These results show a high frequency of colonization and the presence of potentially pathogenic BR-GBN both in hospitals and the community. This highlights the importance of populations who move between those 2 environments, and the need to prevent the spread of bacterial resistance outside hospitals.

The remarkable genetic relationship between Staphylococcus aureus isolates from hemodialysis patients and their household contacts: Homes as an important source of colonization and dissemination

Introduction

Staphylococcus aureus is a successful pathogen in hospital and community. Hemodialysis patients have high colonization rates. Interactions between them and their household contacts, are an opportunity to understand the S. aureus colonization between hospitals and community. This study aims to determine the clinical and epidemiological characteristics of S. aureus colonization in hemodialysis patients and their household contacts, as well as the genetic relationship between their isolates.

Methods

A cross-sectional study was conducted on hemodialysis patients from hospital-associated dialysis center in Medellín-Colombia, and their household contacts between 2019 and 2020. Colonization was assessed in the nostrils for household contacts and nostrils and skin around the catheter insertion for hemodialysis patients. Epidemiological information was obtained, and colonization was evaluated in their pets’ oral cavities. Bacterial identification and susceptibility were assessed using phenotypic and molecular methods. Molecular typing included SCCmec typing, pulsed-field gel electrophoresis (PFGE), spa typing, and virulence factor detection.

Results

Colonization frequency was 35.6% (n = 16/45) in patients (87.5% MSSA– 12.5% MRSA) and 43.1% (n = 53/123) in household contacts (88.7% MSSA—11.3% MRSA). Of 45 homes, 77.8% presented colonized people. Colonization was detected in at least two household members in 46.7% of homes, of which 52.4% had a genetic relationship. Colonization was 16% (n = 4/25) in pets (75% MRSA—25% MSSA). The most frequent clonal complex was CC8 (15.6%), and the spa typing revealed high diversity.

Conclusion

This study shows a high frequency of colonization by S. aureus in both hemodialysis patients and their household contacts and a significant genetic relationship between their isolates. This demonstrates an exchange of this bacterium and that homes are an important source of colonization to patients, highlighting the need for prevention strategies outside the hospital to avoid future infections, and the importance of the populations with permanent transit between the two environments.

[Diagnosis and treatment of catheter-related bloodstream infection in hemodialysis: 10 years later]

Patients in hemodialysis on central venous catheter as vascular access are at risk of infections. Catheter-related bloodstream infection is one of the most serious catheter-complications in hemodialysis patients. Its clinical and microbiological diagnosis is challenging. The implementation of empiric antibiotic therapy is based on old recommendations proposing the combination of a molecule targeting methicillin-resistant Staphylococcus aureus and a betalactamin active on P. aeruginosa, and also adapting this probabilistic treatment by carrying out a microbiological register on a local scale, which is rarely done. In our hemodialysis center at Bordeaux University Hospital, an analysis of the microorganisms causing all catheter-related bloodstream infection over the period 2018-2020 enabled us to propose, in agreement with the infectious disease specialists, an adapted probabilistic antibiotic therapy protocol. This approach allowed us to observe a low incidence of meticillinoresistance of Staphylococcus. For catheters inserted more than 6 months ago, we observed no Staphylococcus, no multi-resistant Pseudomonas, and only 2% of Enterobacteria resistant to cephalosporins. A frequent updating of the microbiological epidemiology of catheter-related bloodstream infection, in partnership with the infectious diseases team in each hemodialysis center, allowing an adaptation of the probabilistic antibiotic therapy, and seems to have a good feasibility. This strategy might favor the preservation of microbial ecology on an individual and collective scale in maintenance hemodialysis patients.

Post-Dialysis Parenteral Antimicrobial Therapy in Patients Receiving Intermittent High-Flux Hemodialysis

Patients with end-stage renal disease (ESRD) requiring intermittent hemodialysis (IHD) are at increased risk of infection, which represents a leading cause of mortality in this population. The use of additional vascular access devices such as peripherally inserted central catheters to treat such infections should be minimized in patients with ESRD requiring IHD in order to mitigate complications such as infection and thrombosis and to maintain venous patency for hemodialysis access. Intravenous antimicrobial dosing following IHD has the advantages of avoiding additional access devices and providing convenience for patients and providers. Vancomycin, cefazolin, and aminoglycosides have historically been regarded as the primary intravenous antimicrobials administered with IHD given their relatively low cost, convenient dosing, and longevity of clinical use. Despite this, a growing body of literature is evaluating the use of an expanded list of antimicrobials that may be employed using post-dialysis dosing for patients requiring IHD; however, the available data are largely limited to pharmacokinetic studies and small cohorts of infected patients or uninfected subjects. Post-dialytic dosing of intravenous antimicrobials may be considered on a patient-by-patient basis after careful consideration of clinical, microbiological, and logistical factors that may influence the probability of treatment success. This document reviews and evaluates currently available information on the post-dialytic administration of an expanded list of intravenous antimicrobials in the setting of thrice-weekly, high-flux IHD.

Staphylococcus aureus colonization increases the risk of bacteremia in hemodialysis patients: a molecular epidemiology approach with time-dependent analysis

BACKGROUND

Bacteremia is the second cause of death in hemodialysis patients and colonization may be a risk factor. We analyzed the association between Staphylococcus aureus or multidrug-resistant Gram-negative bacteria colonization and bacteremia in hemodialysis patients.

METHODS

A prospective cohort study was conducted. Colonization status was determined at baseline, 2, and 6 months later. The time-to-first-bacteremia was analyzed using the baseline status and time-dependent nature of colonization. The recurrence of bacteremia given colonization status was evaluated using a Poisson regression model. The genetic relatedness between isolates that colonized and caused bacteremia were established by molecular typing methods.

RESULTS

Seventy-one patients developed bacteremia over the course of follow-up, with the majority of cases being caused by S aureus (n = 28; 39.4%) and only three caused by multidrug-resistant Gram-negative bacteria. S aureus colonization was associated with an increased risk of bacteremia in time-dependent analysis (HR:4.64; 95%CI: 1.72-12.53) and with recurrence of infection in Poisson model (IRR:5.90, 95%CI: 2.29-15.16). Molecular methods revealed that 77.8% of patients with S aureus bacteremia were colonized with the same strain that caused the infection.

CONCLUSIONS

S aureus is a cause of endogenous infection in hemodialysis patients. Colonization is associated with both time-to-first-bacteremia and the recurrence of infection. The prompt identification of colonized patients and the evaluation of decolonization protocols are needed.

Epidemiology of bloodstream infections in a Scottish haemodialysis population with focus on vascular access method

BACKGROUND

Infection is the second highest cause of mortality in end-stage renal disease, with a significant proportion relating to haemodialysis (HD) vascular access-related infection (VARI).

AIM

To report the rate and antimicrobial resistance (AMR) of all-source bloodstream infections (BSIs) by vascular access type in a Scottish HD cohort.

METHODS

Retrospective analysis was undertaken of data on adult patients attending seven HD units during 2017. Total HD days for each vascular access type were calculated. BSIs were analysed with rates expressed per 1000 HD days. AMR was verified using health board microbiology databases.

FINDINGS

Excluding contaminant organisms, there was an overall BSI rate of 0.57 per 1000 HD days. The highest all-source and vascular access-related infection (VARI) BSI rates per 1000 HD days were in the non-tunnelled central venous catheter (CVC) group (3.11 and 2.07 respectively), followed by tunnelled CVC (1.10 and 0.67), arteriovenous graft (0.51 and 0.31), and finally arteriovenous fistula (0.29 and 0.02). The non-VARI BSI rates were lowest in the arteriovenous graft group. Staphylococci comprised the majority of events, with Staphylococcus aureus implicated in 29%. Gram-negative BSIs were prevalent, particularly in CVC groups, and associated with higher mortality. Multidrug-resistant (MDR) S. aureus and carbapenem resistance were relatively low. MDR Gram-negatives were high compared with the Scottish population.

CONCLUSION

Arteriovenous fistula access is confirmed as having lowest all-source and VARI BSI rates, and arteriovenous graft access the lowest non-VARI BSI rates. Staphylococci remain the prevailing genus; however, the contributions of Gram-negative BSIs, the higher mortality, and proportion of MDR organisms in this group are notable.

A longitudinal study shows intermittent colonization by Staphylococcus aureus with a high genetic diversity in hemodialysis patients

Staphylococcus aureus colonization increases the risk of invasive infections in different groups of patients. We analyzed the dynamics and factors associated with S. aureus colonization in hemodialysis patients. A longitudinal study was conducted at a dialysis center associated with a tertiary health care institution. S. aureus colonization was assessed three times in nostrils and on the skin and was classified as absent, intermittent or persistent. The molecular analysis included pulsed-field gel electrophoresis (PFGE) and spa-typing. Clonal complex was inferred from spa-typing. A model of generalized estimating equations was performed to determine the factors associated with colonization. A total of 210 patients were included. Colonization by methicillin-susceptible (MSSA) and methicillin-resistant (MRSA) isolates was 29.1 % vs. 4.8 %, 29.2 % vs. 6.7 % and 24.1 % vs. 7.1 % in the first, second and third screenings respectively. Most of the colonized patients were intermittent carriers (77.8 %, n = 63). PFGE and spa-typing revealed a high genetic diversity. One third (33.3 %) of the carriers classified as persistent had different clones during follow-up. Clonal complex 8 was frequent among MSSA (28 %) and MRSA (59 %) isolates. Current smoking (OR:7.22, 95 %CI 2.24-23.27), Charlson index (OR:1.22, 95 %CI 1.03-1.43) and previous infection by S. aureus (OR:2.41; 95 %CI:1.09-5.30) were associated with colonization by this microorganism. Colonization increased the risk of bacteremia (HR = 4.9; 95 % CI: 1.9-12.9). In conclusion, the colonization by S. aureus in hemodialysis patients changes over time and acquisition of new clones is a frequent event. These results evidence that patients are repeatedly recolonizing from hospitals, dialysis units and their homes. On the other hand, factors not associated with healthcare, as smoking, can increase the risk of colonization.

High intermittent colonization by diverse clones of β-lactam-resistant Gram-negative bacilli suggests an excessive antibiotic use and different sources of transmission in haemodialysis patients

BACKGROUND

The spread of β-lactam-resistant Gram-negative bacilli (GNB) is a topic of worldwide concern; however, knowledge about colonization by these bacteria in haemodialysis patients is limited.

AIM

To analyse the dynamics and factors associated with colonization by β-lactam-resistant GNB in a dialysis centre.

METHODS

A longitudinal study was conducted. Stool samples were collected for each patient to evaluate extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Gram-negative bacilli. Colonization screens were performed at three time-points and then classified as absent, intermittent, or persistent. Molecular typing included enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST). Clinical information was obtained from medical records and personal interview. A generalized estimating equations model was performed to determinate factors associated with the colonization.

FINDINGS

A total of 210 patients were included. ESBL-producing and carbapenem-resistant GNB colonization reached 41.2% and 11.5%, respectively. Most patients were intermittent carriers with frequencies of 73.9% and 92.95% for each bacteria group. The most frequent ESBL was CTX-M-G1, while the most common carbapenemase was KPC. ERIC-PCR and PFGE revealed high genetic diversity among strains and the Escherichia coli clone ST131 was the most important by MLST. Fluoroquinolone use (odds ratio: 3.13; 95% confidence interval: 1.03-9.44; P [cap] = 0.043) and chronic obstructive lung disease (odds ratio: 3.53; 1.42-8.74; P = 0.006) were associated with ESBL-producing GNB colonization.

CONCLUSION

Our findings indicate a high intermittent colonization by diverse clones of β-lactam-resistant GNB in haemodialysis patients. It suggests excessive antibiotic pressure that favours the acquisition of bacteria with diverse genetic profiles and different transmission sources.

Post-antibiotic era in hemodialysis? Two case reports of simultaneous colonization and bacteremia by multidrug-resistant bacteria

The emergence of resistance mechanisms not only limits the therapeutic options for common bacterial infections but also worsens the prognosis in patients who have conditions that increase the risk of bacterial infections. Thus, the effectiveness of important medical advances that seek to improve the quality of life of patients with chronic diseases is threatened. We report the simultaneous colonization and bacteremia by multidrug-resistant bacteria in two hemodialysis patients. The first patient was colonized by carbapenem- and colistin-resistant Klebsiella pneumoniae, carbapenem-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA). The patient had a bacteremia by MRSA, and molecular typing methods confirmed the colonizing isolate was the same strain that caused infection. The second case is of a patient colonized by extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli and carbapenem-resistant Pseudomonas aeruginosa. During the follow-up period, the patient presented three episodes of bacteremia, one of these caused by ESBL-producing E. coli. Molecular methods confirmed colonization by the same clone of ESBL-producing E. coli at two time points, but with a different genetic pattern to the strain isolated from the blood culture. Colonization by multidrug-resistant bacteria allows not only the spread of these microorganisms, but also increases the subsequent risk of infections with limited treatments options. In addition to infection control measures, it is important to establish policies for the prudent use of antibiotics in dialysis units.

Clinical characteristics, risk factors and microbiology of infections in patients receiving chronic hemodialysis

BACKGROUND

The infectious complications in hemodialysis patients are still among the main reasons for their increased morbidity and mortality. The possible reasons behind this might be due to impairments in the host defense mechanisms, comorbidities, invasive procedures and pathogenicity of the infecting organisms. With the increased incidence of bacteremia in hemodialysis patients and the overt use of antibiotics, we have witnessed a rise in the number of new multidrug resistant (MDR) strains in those patients.

AIM

We aim to determine the epidemiology, risk factors and complications of infections in patients receiving chronic hemodialysis, particularly bloodstream infections.

METHODS

This is a retrospective case-control study involving patients undergoing hemodialysis at a tertiary care center. We studied the prevalence of infectious complications among those patients as well as the responsible agent in each respective infectious episode and the risk factors associated with bacteremia.

FINDINGS

46.6% of the studied population had at least one documented episode of infection. The most common were blood and respiratory infections (33.2% and 32.7% respectively). Among patients with bacteremia, coagulase-negative Staphylococcus was the predominant pathogen (49% of cases), followed by Staphylococcus aureus and Escherichia coli. Mortality was higher in patients who had MDR bacteremia, and in those who had mechanical ventilation or intensive care unit (ICU) admission.

CONCLUSION

Due to the alarming increase in the incidence of infection among hemodialysis patients and its strong association with mortality, further studies are needed to look for risk factors associated with infection and for ways to control those risk factors.

Risk factors for multidrug-resistant organisms among deceased organ donors

Donor infection or colonization with a multidrug-resistant organism (MDRO) affects organ utilization and recipient antibiotic management. Approaches to identifying donors at risk of carrying MDROs are unknown. We sought to determine the risk factors for MDROs among transplant donors. A multicenter retrospective cohort study was conducted at four transplant centers between 2015 and 2016. All deceased donors who donated at least one organ were included. Cultures obtained during the donor's terminal hospitalization and organ procurement were evaluated. The primary outcome was isolation of an MDRO on culture. Multivariable Cox regression was used to determine risk factors associated with time to donor MDRO. Of 440 total donors, 64 (15%) donors grew an MDRO on culture. Predictors of an MDRO on donor culture included hepatitis C viremia (hazard ratio [HR] 4.09, 95% confidence interval [CI] 1.71-9.78, P = .002), need for dialysis (HR 4.59, 95% CI 1.09-19.21, P = .037), prior hematopoietic cell transplant (HR 7.57, 95% CI 1.03-55.75, P = .047), and exposure to antibiotics with a narrow gram-negative spectrum (HR 1.13, 95% CI 1.00-1.27, P = .045). This is the first study to determine risk factors for MDROs among deceased donors and will be important for risk stratifying potential donors and informing transplant recipient prophylaxis.

Antimicrobial resistance in nephrology

The prevalence of antimicrobial resistance among many common bacterial pathogens is increasing. The emergence and global dissemination of these antibiotic-resistant bacteria (ARB) is fuelled by antibiotic selection pressure, inter-organism transmission of resistance determinants, suboptimal infection prevention practices and increasing ease and frequency of international travel, among other factors. Patients with chronic kidney disease, particularly those with end-stage renal disease who require dialysis and/or kidney transplantation, have some of the highest rates of colonization and infection with ARB worldwide. These ARB include methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus spp. and several multidrug-resistant Gram-negative organisms. Antimicrobial resistance limits treatment options and increases the risk of infection-related morbidity and mortality. Several new antibiotic agents with activity against some of the most common ARB have been developed, but resistance to these agents is already emerging and highlights the dire need for new treatment options as well as consistent implementation and improvement of basic infection prevention practices. Clinicians involved in the care of patients with renal disease must be familiar with the local epidemiology of ARB, remain vigilant for the emergence of novel resistance patterns and adhere strictly to practices proven to prevent transmission of ARB and other pathogens.

Cefazolin-gentamicin versus taurolidine-citrate for the prevention of infection in tunneled central catheters in hemodialysis patients: A quasi-experimental trial

BACKGROUND

Catheter-related bloodstream infection (CR-BSI) is one of various complications related to hemodialysis (HD). As a result of the high rate of infection, the use of lock solutions for the prevention of CR-BSI has been studied. However, adverse effects of lock solution, such as increased emergence of strains resistant to antibiotics, which is an important concern, need to be investigated further. The aim of this study was to compare the efficacy of lock solution using a combination of cefazolin and gentamicin versus taurolidine and citrate in reducing CR-BSI in patients undergoing HD and to identify any adverse effects.

METHODS

A prospective observational study was performed at two dialysis centers. Patients using new tunneled central venous catheters (CVC) for HD were included. Patients with a tunneled CVC were assigned to receive either antibiotic lock solution (group 1: gentamicin 7mg/ml+cefazolin 12mg/ml+heparin 3500IU/ml) or lock solution with TauroLock-Hep500 (group 2: taurolidine citrate 4%+heparin 500 IU/ml) during the inter-dialysis period. The patients were allocated to these groups according to the hemodialysis center they were attending.

RESULTS

A total of 145 CVCs were implanted in 127 patients and were followed for 15 months: 77 CVCs (65 patients) were placed in group 1 and 68 CVCs (62 patients) in group 2. There was no difference between the two groups with regard to CR-BSI (events per 1000 catheter-days: group 1=0.79, group 2=1.10; p=0.18) or exit site infection rates (events per 1000 catheter-days: group 1=2.45, group 2=1.83; p=0.37). The groups differed in ESI pathogens, with gram-positive oxacillin-resistant pathogens more frequent in group 1 (31.8% vs. 5.0%; p=0.003). The two groups were similar in mechanical complications. In the Cox regression analysis, the internal jugular vein site was a protective factor for all catheter removal complications (hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.19-0.91) and mechanical complications (HR 0.16, 95% CI 0.065-0.41); only ESI was a risk factor for all catheter removal complications (HR 1.79, 95% CI 1.04-3.07) and mechanical complications (HR 5.64, 95% CI 1.65-19.3).

CONCLUSIONS

The efficacy of both lock solutions was similar in preventing infections related to tunneled CVCs for HD. However, there were more oxacillin-resistant strains in patients who received antibiotic lock solution. Further studies are required to determine the optimal drug regimen and concentrations for lock solution and the associated adverse effects.

Clinical epidemiology of infectious disease among patients with chronic kidney disease

Infectious disease is recognized as an important complication among patients with end-stage renal disease, contributing to excess morbidity and health care costs. However, recent epidemiological studies have revealed that even mild to moderate stages of chronic kidney disease (CKD) substantially increase risk of infection. Regarding underlying mechanisms, evidence suggests various aspects of altered immune response in patients with CKD including impaired function of T cells, B cells and neutrophil. Multiple conditions surrounding CKD, such as older age, diabetes, and cardiovascular disease are important contributors in the increased susceptibility to infection in this population. In addition, several mechanisms impairing immune function have been hypothesized including accumulated uremic toxins, increased oxidative stress, endothelial dysfunction, low-grade inflammation, and mineral and bone disorders. In terms of prevention strategies, influenza and pneumococcal vaccines are most feasible and important. Nevertheless, the extent of vaccine utilization in CKD has not been well documented. In addition, antibody response to vaccination may be reduced in CKD patients, and thus a vaccine delivery strategy (e.g., dose and frequency) may need to be optimized among patients with CKD. Through this review, we demonstrate that infection is a major but underrecognized complication of CKD. As CKD is recognized as a serious public health issue, dedicated research is needed to better characterize the burden of infectious disease associated with CKD, understand the pathophysiology of infection in patients with CKD, and develop effective strategies to prevent infection and its sequela in this high risk population.

Carbapenem-Resistant Enterobacteriaceae Infections in Patients on Renal Replacement Therapy

BACKGROUND

Patients on chronic intermittent renal replacement therapy (RRT) are at risk for infection with carbapenem-resistant Enterobacteriaceae (CRE). However, the impact of RRT on outcomes after CRE infections remains to be defined. Here we perform a comparison of outcomes for CRE-infected patients with preserved renal function compared with CRE-infected patients on RRT.

METHODS

Cases and controls were defined from a prospective cohort of CRE-infected patients from the Consortium on Resistance against Carbapenems in Klebsiella and other Enterobacteriaceae (CRACKLE). Cases were defined as CRE-infected patients on RRT at hospital admission, while controls were defined as CRE-infected patients with serum creatinine <2 mg/dL and not receiving RRT at admission. Risk factors for 28-day in-hospital mortality were assessed using multivariable logistic regression. An ordinal ranking of outcomes by desirability analysis was performed.

RESULTS

Patients on RRT were more likely to have diabetes mellitus and cardiac disease than controls. Urinary sources of infection were less common in the RRT group. In RRT patients, 28-day in-hospital mortality was increased as compared with controls: 22/71 (31%) vs 33/295 (11%). RRT remained significantly associated with 28-day in-hospital mortality after adjustment for source of infection, prehospitalization origin, and severity of illness (adjusted odds ratio, 2.27; 95% confidence interval [CI], 1.09-4.68; P = .03). Using univariable desirability of outcome ranking analysis, RRT status was associated with a 68% (95% CI, 61%-74%) chance of a worse disposition outcome.

CONCLUSIONS

Chronic RRT in CRE-infected patients is associated with increased in-hospital mortality and worse disposition outcomes at 28 days.

National Healthcare Safety Network (NHSN) Dialysis Event Surveillance Report for 2014

BACKGROUND AND OBJECTIVES

Persons receiving outpatient hemodialysis are at risk for bloodstream and vascular access infections. The Centers for Disease Control and Prevention conducts surveillance for these infections through the National Healthcare Safety Network. We summarize 2014 data submitted to National Healthcare Safety Network Dialysis Event Surveillance.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Dialysis facilities report three types of dialysis events (bloodstream infections; intravenous antimicrobial starts; and pus, redness, or increased swelling at the hemodialysis vascular access site). Denominator data consist of the number of hemodialysis outpatients treated at the facility during the first 2 working days of each month. We calculated dialysis event rates stratified by vascular access type (e.g., arteriovenous fistula, arteriovenous graft, or central venous catheter) and standardized infection ratios (comparing individual facility observed with predicted numbers of infections) for bloodstream infections. We described pathogens identified among bloodstream infections.

RESULTS

A total of 6005 outpatient hemodialysis facilities reported dialysis event data for 2014 to the National Healthcare Safety Network. These facilities reported 160,971 dialysis events, including 29,516 bloodstream infections, 149,722 intravenous antimicrobial starts, and 38,310 pus, redness, or increased swelling at the hemodialysis vascular access site events; 22,576 (76.5%) bloodstream infections were considered vascular access related. Most bloodstream infections (63.0%) and access-related bloodstream infections (69.8%) occurred in patients with a central venous catheter. The rate of bloodstream infections per 100 patient-months was 0.64 (0.26 for arteriovenous fistula, 0.39 for arteriovenous graft, and 2.16 for central venous catheter). Other dialysis event rates were also highest among patients with a central venous catheter. Facility bloodstream infection standardized infection ratio distribution was positively skewed with a median of 0.84. Staphylococcus aureus was the most commonly isolated bloodstream infection pathogen (30.6%), and 39.5% of S. aureus isolates tested were resistant to methicillin.

CONCLUSIONS

The 2014 National Healthcare Safety Network Dialysis Event data represent nearly all United States outpatient dialysis facilities. Rates of infection and other dialysis events were highest among patients with a central venous catheter compared with other vascular access types. Surveillance data can help define the epidemiology of important infections in this patient population.

Comparison of Staphylococcal Flora in Denture Plaque and the Surface of the Pharyngeal Mucous Membrane in Kidney Transplant Recipients

BACKGROUND

Biofilm occurring on removable prostheses is a reservoir of bacterial flora, consisting of both physiological and pathogenic multidrug-resistant microorganisms. Patients undergoing dialysis and organ transplantation are particularly prone to bacterial infections, which can have its source in denture plaque. This study was a comparison of the composition of staphylococcal flora within the surface of the pharyngeal mucous membrane as well as denture plaque in kidney transplant recipients.

METHODS

The study included 44 subjects with removable prostheses who reported for a kidney transplant procedure. Swab samples were collected from prostheses and the pharyngeal wall. Isolated strains were identified and investigated for drug resistance.

RESULTS

A total of 72 strains of Staphylococcus were isolated from the denture plaque and 53 from the pharynx. In the pharynx, the following species prevailed: Staphylococcus epidermidis, Staphylococcus warneri, and Staphylococcus aureus. The following species prevailed in denture plaque: S epidermidis, S aureus, and Staphylococcus haemolyticus. Among the pharyngeal strains, antibiotic resistance most commonly referred to natural penicillin (77%), constitutive macrolide-lincosamide-streptogramin B resistance (28%), and tetracycline (26.4%). In case of denture plaque, the highest percentage of strains demonstrated resistance to natural penicillin (60%), fosfomycin (32%), and cefoxitin (25%). In 10 subjects (48%), Staphylococcus-induced infections occurred in the first year after transplantation, 5 of which had the same bacterial strain as cultured previously from dentures.

CONCLUSIONS

The denture biofilm and surface of the pharynx differ in terms of bacterial composition and bacterial drug resistance profiles. Denture plaque constitutes a considerable reservoir of staphylococcal flora, which can be a potential source of infection in organ transplant recipients.

Three-times-weekly, post-dialysis cefepime therapy in patients on maintenance hemodialysis: a retrospective study

BACKGROUND

In hemodialysis patients, post-dialysis treatment with intravenous antibiotics permits even severe infections to be managed on an outpatient basis. Cefepime is a fourth-generation cephalosporin with a broad spectrum of action in monotherapy. We report on the pharmacokinetics of cefepime in post-dialysis therapy.

METHODS

Since June 2012, twelve infections were treated with post-dialysis cefepime in 9 patients on high-flux hemodialysis. The initial post-dialysis dose of cefepime was approximately 15 mg/kg. The following doses were adapted according to the trough serum levels obtained before the subsequent dialysis in order to be above the EUCAST breakpoints for susceptible organisms and above the MIC90. Residual plasma concentrations were determined before (n = 30) and after (n = 17) dialysis by liquid chromatography-mass spectrometry.

RESULTS

Overall, the mean ± SD dose of cefepime was 920 ± 270 mg (14.5 ± 5.1 mg/kg), but it was significantly lower before the 48 h interval (775 ± 210 mg or 12.7 ± 4.5 mg/kg) compared to the 72 h interval (1125 ± 225 mg or 17.2 ± 4.9 mg/kg) (p < 0.05). The mean trough pre-dialysis concentrations were 10.7 ± 3.9 mg/l and 11.3 ± 5.6 mg/l at 48 and 72 h, respectively. These levels always largely exceeded the EUCAST susceptibility breakpoints for all the targeted bacteria (>1 mg/l) with the exception of Pseudomonas aeruginosa (>8 mg/l). Cefepime concentrations were higher in anuric patients compared to those with preserved diuresis (15.6 ± 3.5 vs 9.25 ± 3.6 mg/l; p < 0.001) and decreased on average by 81 % during dialysis (from 10.5 ± 3.7 to 1.96 ± 1.2 mg/l; p < 0.001). The clinical outcome of all patients was good.

CONCLUSIONS

Outpatient treatment with cefepime administered post-dialysis three-times-weekly was effective and well-tolerated in our patients. According to our data, in patients infected by highly susceptible pathogens a fixed dose of cefepime of 1 g before every 48-h interval and of 1.5 g before every 72-h interval should be recommended, without need of routine monitoring of the cefepime blood levels. In patients having an infection with less susceptibles pathogens as P. aeruginosa, and particularly in those among them exhibiting residual renal function, higher initial doses are necessary (1.5 g before a 48-h interval and 2.0 g before a 72-h interval) with adaption according to the subsequent pre-dialysis trough serum levels.

Honey in the Prevention and Treatment of Infection in the CKD Population: A Narrative Review

Infection is a major cause of morbidity and mortality at all stages of chronic kidney disease (CKD). Multiresistant organisms are becoming increasingly common, particularly in the CKD population. Unfortunately, the rapid evolution of antibiotic resistance has not been mirrored by innovation in new antibiotic agents. Novel treatments are therefore urgently needed. Honey has garnered much interest due to its broad-spectrum antibacterial properties based on extensive experimental data. Unlike conventional antibiotics, honey has an added advantage as it appears to avoid inducing antimicrobial resistance in bacteria. This review discusses the potential mechanisms of action and role of honey in infection management in the general population, epidemiology and special challenges of infections in CKD populations, and the clinical trial evidence pertaining to the safety and efficacy of honey for the prevention and treatment of infections in CKD population.

Extracorporeal clearance of colistin methanesulphonate and formed colistin in end-stage renal disease patients receiving intermittent haemodialysis: implications for dosing

OBJECTIVES

Colistin, administered intravenously as its inactive prodrug colistin methanesulphonate (CMS), is being increasingly used. However, there is very limited information available on the impact of haemodialysis (HD) on the pharmacokinetics of CMS and formed colistin.

PATIENTS AND METHODS

A single 30 min intravenous dose of CMS (150 mg of colistin base activity) was administered to 10 patients undergoing HD. HD was performed from 1.5 to 5.5 h after the start of the CMS infusion. Serial blood samples were collected over 50 h, additional blood samples pre- and post-dialysis membrane at three timepoints during HD, dialysate samples at four timepoints during HD, and a cumulative urine sample over 24 h. CMS and colistin were determined by HPLC. Population modelling and determination of HD clearance by multiple methods was conducted.

RESULTS

The average amount of CMS recovered in the dialysate was 30.6% of the dose administered. The concentrations of CMS and colistin in the plasma and the amounts of CMS recovered in the dialysate were well described by the population disposition model. The clearance of CMS by dialysis as estimated by population analysis based on systemic plasma concentrations and amounts in the dialysate was 4.26 L/h (26% coefficient of variation). The dialysis clearance determined from the pre- and post-membrane plasma concentrations was 5.67 L/h (21%) for CMS and 3.99 L/h (44%) for colistin. Thus, CMS clearance by dialysis from trans-cartridge extraction was ∼30% higher than when calculated based on the amount in dialysate, suggesting adsorption to the membrane.

CONCLUSIONS

Due to the extensive removal of CMS by dialysis, HD should be conducted at the end of a dosing interval and a supplemental dose should be administered.

Risk factors for morbidity and mortality of bloodstream infection in patients undergoing hemodialysis: a nested case-control study

BACKGROUND

Infection is the leading cause of morbidity and the second most frequent cause of mortality among patients on renal replacement therapy. A major morbid event in this population is hospitalization because of infection. The aim of this study was to investigate the risk factors for morbidity and mortality related to bloodstream infection (BSI) among patients on hemodialysis.

RESULTS

Risk factors for morbidity and mortality related to BSI in patients on hemodialysis were investigated retrospectively by nested case-control, from January 2010 to June 2013. Patients were divided into two groups: those who progressed to hospitalization or death due to BSI (Group 1) and those who developed BSI, but did not progress to the same outcome (Group 2). Data were collected through consultation of patient records. For statistical analysis, logistic regression was used. There were 32 patients in Group 1 and 61 in Group 2. Logistic regression verified that, for each year of age, the chance of death or hospitalization for BSI increased 1.05 times [95% confidence interval (CI): 1.02-1.09]. Patients with BSI caused by Staphylococcus aureus had an 8.67 times higher chance of progressing to death or hospitalization (95% CI: 2.5-30.06). The isolation of multiresistant microorganisms in blood cultures of hemodialysis patients increased morbidity and mortality by 2.75 times (95% CI: 1.01-7.48).

CONCLUSION

Independent risk factors for morbidity and mortality among patients after developing BSI during hemodialysis were: age, blood culture positive for S. aureus, and antibiotic resistance. Control measures to prevent microbial dissemination, primarily the multiresistant ones, should be intensified in this population. More studies are needed to standardize specific measures not yet classically standardized, such as collection of surveillance culture samples, contact precautions, and decolonization.