Novel antimicrobial-resistant bacteria among patients requiring chronic hemodialysis

The cost of hospitalizations for treatment of hemodialysis catheter-associated blood stream infections in children: a retrospective cohort study

BACKGROUND

Hospitalization costs for treatment of hemodialysis (HD) catheter-associated blood stream infections (CA-BSI) in adults are high. No studies have evaluated hospitalization costs for HD CA-BSI in children or identified factors associated with high-cost hospitalizations.

METHODS

We analyzed 160 HD CA-BSIs from the Standardizing Care to Improve Outcomes in Pediatric End-stage Kidney Disease (SCOPE) collaborative database linked to hospitalization encounters in the Pediatric Health Information System (PHIS) database. Charge-to-cost ratios were used to convert hospitalization charges reported in PHIS database to estimated hospital costs. Generalized linear mixed modeling was used to assess the relationship between higher-cost hospitalization (cost above 50^th percentile) and patient and clinical characteristics. Generalized linear regression models were used to assess differences in mean service line costs between higher- and lower-cost hospitalizations.

RESULTS

The median (IQR) length of stay for HD CA-BSI hospitalization was 5 (3-10) days. The median (IQR) cost for HD CA-BSI hospitalization was $18,375 ($11,584-$36,266). ICU stay (aOR 5.44, 95% CI 1.62-18.26, p = 0.01) and need for a catheter procedure (aOR = 6.08, 95% CI 2.45-15.07, p < 0.001) were associated with higher-cost hospitalization.

CONCLUSIONS

Hospitalizations for HD CA-BSIs in children are often multiple days and are associated with substantial costs. Interventions to reduce CA-BSI may reduce hospitalization costs for children who receive chronic HD. A higher resolution version of the Graphical abstract is available as Supplementary information.

COVID-19 modeling and non-pharmaceutical interventions in an outpatient dialysis unit

This paper describes a data-driven simulation study that explores the relative impact of several low-cost and practical non-pharmaceutical interventions on the spread of COVID-19 in an outpatient hospital dialysis unit. The interventions considered include: (i) voluntary self-isolation of healthcare personnel (HCPs) with symptoms; (ii) a program of active syndromic surveillance and compulsory isolation of HCPs; (iii) the use of masks or respirators by patients and HCPs; (iv) improved social distancing among HCPs; (v) increased physical separation of dialysis stations; and (vi) patient isolation combined with preemptive isolation of exposed HCPs. Our simulations show that under conditions that existed prior to the COVID-19 outbreak, extremely high rates of COVID-19 infection can result in a dialysis unit. In simulations under worst-case modeling assumptions, a combination of relatively inexpensive interventions such as requiring surgical masks for everyone, encouraging social distancing between healthcare professionals (HCPs), slightly increasing the physical distance between dialysis stations, and-once the first symptomatic patient is detected-isolating that patient, replacing the HCP having had the most exposure to that patient, and relatively short-term use of N95 respirators by other HCPs can lead to a substantial reduction in both the attack rate and the likelihood of any spread beyond patient zero. For example, in a scenario with R0 = 3.0, 60% presymptomatic viral shedding, and a dialysis patient being the infection source, the attack rate falls from 87.8% at baseline to 34.6% with this intervention bundle. Furthermore, the likelihood of having no additional infections increases from 6.2% at baseline to 32.4% with this intervention bundle.

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.

High frequency of colonization by diverse clones of beta-lactam-resistant Gram-negative bacilli in haemodialysis: different sources of transmission outside the renal unit?

Introduction. While colonization by Staphylococcus aureus in haemodialysis patients has been assessed, knowledge about colonization by beta-lactam-resistant Gram-negative bacilli is still limited.Aim. To describe clinical and molecular characteristics in haemodialysis patients colonized by S. aureus (MSSA-MRSA) and beta-lactam-resistant Gram-negative bacilli in an ambulatory renal unit.Methodology. The study included patients with central venous catheters in an outpatient haemodialysis facility in Medellín, Colombia (October 2017-October 2018). Swab specimens were collected from the nostrils and skin around vascular access to assess colonization by S. aureus (MSSA-MRSA). Stool samples were collected from each patient to evaluate beta-lactam-resistant Gram-negative bacilli colonization. Molecular typing included PFGE, multilocus sequence typing (MLST), spa typing and enterobacterial repetitive intergenic consensus-PCR (ERIC). Clinical information was obtained from medical records and personal interview.Results. A total of 210 patients were included in the study. S. aureus colonization was observed in 33.8 % (n=71) of the patients, 4.8 % (n=10) of which were colonized by methicillin-resistant S. aureus. Stool samples were collected from 165 patients and of these 41.2 % (n=68) and 11.5 % (n=19) were colonized by extended-spectrum-beta-lactamase-producing (ESBL) and carbapenem-resistant bacilli, respectively. Typing methods revealed high genetic diversity among S. aureus and ESBL-producing Gram-negative bacilli (ESBL-GNB). Antibiotic use and hospitalization in the previous 6 months were observed in more than half of the studied population.Conclusion. The high colonization by ESBL-GNB in haemodialysis patients shows evidence for the need for stronger surveillance, not only for S. aureus but also for multidrug-resistant bacilli in order to avoid their spread. Additionally, the high genetic diversity suggests other sources of transmission outside the renal unit instead of horizontal transmission between patients.

Determinación de los factores de riesgo en sepsis por Enterococcus vancomicino resistente. Estudio de casos y controles en pacientes críticamente enfermos

Introducción: las infecciones causadas por Enterococcus resistente a Vancomicina (EVR) presentan mayor mortalidad en pacientes críticos, asociado a un aumento gradual en este patrón de resistencia, especialmente en el continente americano, por lo cual la adecuada terapia antimicrobiana empírica es fundamental para mejorar los desenlaces. Objetivo: determinar los factores de riesgo asociados al desarrollo de infección por EVR en pacientes sépticos en la Unidad de Cuidados Intensivos (UCI) del Hospital San José en Bogotá, Colombia. Métodos: Estudio descriptivo de casos y controles en pacientes sépticos ingresados a la UCI durante 2016 y 2017. Los casos se definieron como pacientes con infección por EVR y los controles los pacientes con infección por otro germen. Resultados: se incluyeron 32 pacientes con aislamiento de EVR y 96 controles. Los factores de riesgo asociados a infección por EVR fueron: nutrición parenteral(OR 15,7 IC 4,2-71,4), lavado peritoneal (OR 8,9 IC 3,2-24,8), cultivo polimicrobiano (OR 19,9 IC 6,0-83,4). La mortalidad fue 56,2% en casos y 33,3% en controles. Conclusiones: Los factores de riesgo hallados con mayor frecuencia fueron: múltiples lavados peritoneales, nutrición parenteral y cultivos polimicrobianos. Encontramos una correlación significativa en el uso de antibiótico empírico adecuado y la reducción en la mortalidad.

Clinical and Economic Benefits of Antimicrobial Stewardship Programs in Hemodialysis Facilities: A Decision Analytic Model

BACKGROUND AND OBJECTIVES

Infections caused by multidrug-resistant organisms and Clostridium difficile are associated with substantial morbidity and mortality as well as excess costs. Antimicrobial exposure is the leading cause for these infections. Approximately 30% of antimicrobial doses administered in outpatient hemodialysis facilities are considered unnecessary. Implementing an antimicrobial stewardship program in outpatient hemodialysis facilities aimed at improving prescribing practices would have important clinical and economic benefits.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We developed a decision analytic model of antimicrobial use on the clinical and economic consequences of implementing a nationwide antimicrobial stewardship program in outpatient dialysis facilities. The main outcomes were total antimicrobial use, infections caused by multidrug-resistant organisms and C. difficile, infection-related mortality, and total costs. The analysis considered all patients on outpatient hemodialysis in the United States. The value of implementing antimicrobial stewardship programs, assuming a 20% decrease in unnecessary antimicrobial doses, was calculated as the incremental differences in clinical end points and cost outcomes. Event probabilities, antimicrobial regimens, and health care costs were informed by publicly available sources.

RESULTS

On a national level, implementation of antimicrobial stewardship programs was predicted to result in 2182 fewer infections caused by multidrug-resistant organisms and C. difficile (4.8% reduction), 629 fewer infection-related deaths (4.6% reduction), and a cost savings of $106,893,517 (5.0% reduction) per year. The model was most sensitive to clinical parameters as opposed to antimicrobial costs.

CONCLUSIONS

The model suggests that implementation of antimicrobial stewardship programs in outpatient dialysis facilities would result in substantial reductions in infections caused by multidrug-resistant organisms and C. difficile, infection-related deaths, and costs.

Medical safety in the care of the person with end-stage kidney disease

Much is written about medical safety as it pertains to patients with chronic kidney disease, yet the transition to end-stage kidney disease and processes inherent to the receipt of dialysis present unique safety challenges in this population. Educational efforts in medical safety need to focus on the areas of greatest threat and where intervention can provide the greatest benefit. This study addresses such safety topics in the dialysis population and identifies potential strategies that may aid in harm reduction.

Vancomycin-Resistant Enterococci: Therapeutic Challenges in the 21st Century

Vancomycin-resistant enterococci are serious health threats due in part to their ability to persist in rugged environments and their propensity to acquire antibiotic resistance determinants. Enterococci have now established a home in our hospitals and possess mechanisms to defeat most currently available antimicrobials. This article reviews the history of the struggle with this pathogen, what is known about the traits associated with its rise in the modern medical environment, and the current understanding of therapeutic approaches in severe infections caused by these microorganisms. As the 21st century progresses, vancomycin-resistant enterococci continue to pose a daunting clinical challenge.

Factors associated with the receipt of antimicrobials among chronic hemodialysis patients

BACKGROUND

Antimicrobial use is common among patients receiving chronic hemodialysis (CHD) and may represent an important antimicrobial stewardship opportunity. The objective of this study is to characterize CHD patients at increased risk of receiving antimicrobials, including not indicated antimicrobials.

METHODS

We conducted a prospective cohort study over a 12-month period among patients receiving CHD in 2 outpatient dialysis units. Each parenteral antimicrobial dose administered was characterized as indicated or not indicated based on national guidelines. Patient factors associated with receipt of antimicrobials and receipt of ≥1 inappropriate antimicrobial dose were analyzed.

RESULTS

A total of 89 of 278 CHD patients (32%) received ≥1 antimicrobial doses and 52 (58%) received ≥1 inappropriately indicated dose. Patients with tunneled catheter access, a history of colonization or infection with a multidrug-resistant organism, and receiving CHD sessions during daytime shifts were more likely to receive antimicrobials (odds ratio [OR], 5.16; 95% confidence interval [CI], 2.72-9.80; OR, 5.43; 95% CI, 1.84-16.06; OR, 4.59; 95% CI, 1.20-17.52, respectively). Patients with tunneled catheter access, receiving CHD at dialysis unit B, and with a longer duration of CHD prior to enrollment were at higher risk of receiving an inappropriately indicated antimicrobial dose (incidence rate ratio, 2.23; 95% CI, 1.16-4.29; incidence rate ratio, 2.67; 95% CI, 1.34-5.35; incidence rate ratio, 1.11; 95% CI, 1.01-1.23, respectively).

CONCLUSIONS

This study of all types of antimicrobials administered in 2 outpatient dialysis units identified several important factors to consider when developing antimicrobial stewardship programs in this health care setting.

Evaluating Infection Prevention Strategies in Out-Patient Dialysis Units Using Agent-Based Modeling

Patients receiving chronic hemodialysis (CHD) are among the most vulnerable to infections caused by multidrug-resistant organisms (MDRO), which are associated with high rates of morbidity and mortality. Current guidelines to reduce transmission of MDRO in the out-patient dialysis unit are targeted at patients considered to be high-risk for transmitting these organisms: those with infected skin wounds not contained by a dressing, or those with fecal incontinence or uncontrolled diarrhea. Here, we hypothesize that targeting patients receiving antimicrobial treatment would more effectively reduce transmission and acquisition of MDRO. We also hypothesize that environmental contamination plays a role in the dissemination of MDRO in the dialysis unit. To address our hypotheses, we built an agent-based model to simulate different treatment strategies in a dialysis unit. Our results suggest that reducing antimicrobial treatment, either by reducing the number of patients receiving treatment or by reducing the duration of the treatment, markedly reduces overall colonization rates and also the levels of environmental contamination in the dialysis unit. Our results also suggest that improving the environmental decontamination efficacy between patient dialysis treatments is an effective method for reducing colonization and contamination rates. These findings have important implications for the development and implementation of future infection prevention strategies.

Streptococcus acidominimus causing invasive disease in humans: a case series

INTRODUCTION

Streptococcus acidominimus is a member of the viridans group streptococci and is rarely pathogenic in humans, making it difficult to assess its epidemiologic and clinical significance.

CASE PRESENTATION

We report the cases of five Han Chinese patients with invasive diseases caused by S. acidominimus over a one-year time frame. Three of the patients developed continuous fever after surgery, consisting of a successful elective laparoscopic cholecystectomy (case 1), a laparoscopic esophageal resection and gastroesophageal anastomosis (case 2), and a liver transplant in a patient with liver cancer (case 3). For these three patients, cultures of the purulent drainage material grew S. acidominimus. Case 4 concerns a 52-year-old man who developed sepsis 48 hours after hospitalization for hepatitis, liver cirrhosis and hepatitis-related glomerulonephritis. Case 5 concerns a 55-year-old woman receiving regular hemodialysis who had low-grade fever for one month. For these two patients, blood cultures grew S. acidominimus. An antimicrobial susceptibility test revealed that S. acidominimus was resistant to clindamycin and, to some degree, beta-lactam or macrolides. The S. acidominimus from the patient on hemodialysis was resistant to multiple antibiotics.

CONCLUSION

S. acidominimus is an ever-increasing cause of disease, especially in patients who are critically ill. It is showing increased resistance to antimicrobial agents, so in patients with viridans group streptococci infections, it is necessary to identify the species to improve the clinical management of S. acidominimus.

Reevaluation of ceftazidime dosing recommendations in patients on continuous ambulatory peritoneal dialysis

While intraperitoneal (i.p.) ceftazidime is commonly used to treat continuous ambulatory peritoneal dialysis (CAPD)-related infections, the ability of i.p. regimens to achieve critical pharmacodynamic targets in both blood and dialysate has not been reported. To understand the pharmacodynamic profile of ceftazidime during CAPD, data were obtained from a single-dose pharmacokinetic (PK) i.p. ceftazidime study that included 10 CAPD patients who received i.p. ceftazidime at 15 mg/kg of body weight. The probability of target attainment (concentrations maintained above the MIC for >60% of the dosing interval [60% T > MIC]) was determined for six simulated regimens. A 3-compartment model with each dialysis dwell modeled as a separate differential equation was fit to ceftazidime concentrations using BigNPAG. Embedded with the final PK model, serum and dialysate concentration-time profiles of ceftazidime at 1, 1.5, and 2 g i.p. every 24 h (q24h) to q48h were simulated using ADAPT 5. The mean population pharmacokinetic parameters were as follows: apparent volume of the central compartment (Vc), 7.57 liter; apparent volume of the peritoneal cavity (Vpd), 2.44 liter; clearance from the central compartment (CL), 0.379 liter/h; intercompartmental transfer rate constants (first order) between the central and peripheral compartments (k12 and k21), 4.66 and 4.88 h(-1), respectively; and intercompartmental transfer rate constants (first order) between the central and peritoneal compartments (k13 and k31), 0.111 and 0.227 h(-1), respectively. In serum, the probability of target attainment for MICs of ≤8 mg/liter exceeded 90% for 1.5 to 2 g i.p. q24h to q48h. However, no tested regimen provided adequate dialysate exposure at MICs of ≥8 mg/liter on day 1 without the use of a 3-g loading dose (post hoc analysis). On day 2, 1.5 to 2 g i.p. q24h or 2 g i.p. q48h provided adequate exposure in the peritoneal cavity. These results should be validated in the presence of infection. Ceftazidime i.p. at 1.5 or 2 g q24h to q48h is recommended for nonperitoneal infections. For peritonitis, a 3-g load with maintenance dosing of 1 to 2 g i.p. q24h or 2 g i.p. q48h is recommended.

Antimicrobial use in outpatient hemodialysis units

OBJECTIVE

To quantify and characterize overall antimicrobial use, including appropriateness of indication, among patients receiving chronic hemodialysis.

DESIGN

Retrospective and prospective observational study.

SETTING

Two outpatient hemodialysis units.

PATIENTS

All patients receiving chronic hemodialysis.

METHODS

The rate of parenteral antimicrobial use (number of doses per 100 patient-months) was calculated retrospectively from September 2008 through July 2011. Indication and appropriateness of antimicrobial doses were characterized prospectively from August 2010 through July 2011. Inappropriate administration was defined as occasions when criteria for infection based on national guidelines were not met, failure to choose a more narrow-spectrum antimicrobial on the basis of culture data, or occasions when indications for surgical prophylaxis were not met.

RESULTS

Over the 35-month retrospective study period, the rate of parenteral antimicrobial use was 32.9 doses per 100 patient-months. Vancomycin was the most commonly prescribed antimicrobial, followed by cefazolin and third- or fourth-generation cephalosporins. Over the 12-month prospective study, 1,003 antimicrobial doses were prescribed. Among the 926 (92.3%) doses for which an indication for administration was available, 276 (29.8%) were classified as inappropriate. Of these, a total of 146 (52.9%) did not meet criteria for infection, 74 (26.8%) represented failure to choose a more narrow-spectrum antimicrobial, and 56 (20.3%) did not meet criteria for surgical prophylaxis. The most common inappropriately prescribed antimicrobials were vancomycin and third- or fourth- generation cephalosporins.

CONCLUSIONS

Parenteral antimicrobial use was extensive, and as much as one-third was categorized as inappropriate. The findings of this study provide novel information toward minimizing inappropriate antimicrobial use.