Growth of microorganisms in total parenteral nutrition solutions containing lipid

Analysis for Candida albicans in samples of intravenous lipids administered to premature infants with the goal of optimizing the use of the 1.2 µm filter

Introduction

Introduction: parenteral nutrition is a mixture of macro and micronutrients necessary for the premature infant who cannot be fed enterally. The binary mixture contains carbohydrates, amino acids and micronutrients in one bag and intravenous lipids in another. The latter are more susceptible to microbial contamination, especially by Candida albicans. For this reason, many professional associations typically recommend the use of a single filter in line "Y"; however, this has not yet become standard hospital practice. Aim: to determine the presence of Candida albicans in devices that contain intravenous lipids used in neonates and relate it to the correct use of the 1.2 µm filter. Method: three groups of samples consisting of the remains of a lipid solution (ML) administered to the premature patient for 24 h seeded on Sabouraud agar organized as follows: (ML1), lipid solution obtained directly from the ethinyl vinyl acetate bag were evaluated. (ML2): filtered lipid solution with a 1.2 µm device connected directly to the catheter. (ML3): solution of lipids intentionally contaminated with Candida and subsequently filtered. Results: Candida albicans was not detected in any of the filtered simples (ML2 and ML3) and also not detected in any of the unfiltered simples (ML1). Conclusions: there was no presence of Candida albicans in the lipid solutions used directly with a 1.2 µm filter, however, the use of a single 1.2 µm filter in line "Y" is recommended according to international standards to save the health system.

Metabolic impact of high lipid low dextrose parenteral nutrition

BACKGROUND

Parenteral nutrition (PN) containing 100% soybean oil lipids and high amounts of dextrose may lead to liver dysfunction and hyperglycemia. Mixed lipids have less pro-inflammatory components, so higher doses may be given to decrease the amount of dextrose provided. The purpose of this study is to provide a descriptive analysis of patients who received PN with high mixed lipid and low dextrose content versus PN with lower 100% soybean oil lipid and high dextrose content.

METHODS

We retrospectively reviewed 62 patients aged ≥18 years receiving PN ≥ 7 days from 2016 to 2021 in an acute care hospital. Participants were divided into two groups: high lipid low dextrose (HLLD) containing a four-oil lipid (>30% kcal or ≥1 g/kg) vs adequate lipid high dextrose (ALHD) containing a 100% soybean oil lipid (<30% kcal or <1 g/kg SO-ILE).

RESULTS

Patients in the HLLD group (n = 31) had 64.1% lower incidence of blood glucose levels >180 mg/dL, decreased insulin requirements, 52.7% lower alkaline phosphatase levels, 40.6% higher prealbumin levels, and 42.6% lower c-reactive protein levels while maintaining similar calorie targets compared to the ALHD group (n = 31).

CONCLUSION

Changing from 100% soybean oil to a mixed lipid in PN is helpful to reduce soybean oil intake. However, it is also important to increase the mixed lipid dose to decrease the amount of dextrose provided. PNs containing higher amounts of mixed lipids (40-45% kcal) with lower amounts of dextrose (20-30% kcal) may have clinical benefits that warrant further exploration.

A scoring system based on novel biomarkers and clinical risk factors to predict invasive candidiasis in immunocompetent critically ill patients

Background

Delayed diagnosis further increases the mortality of invasive candidiasis (IC) in intensive care unit (ICU) patients. This study aimed to develop and validate a score based on novel serological biomarkers and clinical risk factors for predicting IC in immunocompetent ICU patients.

Methods

We retrospectively collected clinical data and novel serological markers on admission to ICU. Multivariate logistic regression was used to identify the risk factors associated with IC, which were adopted to establish a scoring system.

Results

Patients with IC had a higher C-reactive protein-to-albumin ratio (CAR) and neutrophil-to-lymphocyte ratio (NLR) and lower prognostic nutritional index than those without IC. The NLR, CAR, sepsis, total parenteral nutrition, 1,3-β-D-glucan (BDG)-positivity, and Sequential Organ Failure Assessment score were identified as independent risk factors for IC by multivariate logistic regression analysis and entered into the final scoring system. The area under receiver operating characteristic curve of the score were 0.883 and 0.892, respectively, in the development and validation cohort, higher than Candida score (0.883 vs.0.730, p &lt; 0.001).

Conclusion

We established a parsimonious score based on NLR, CAR, BDG-positivity, and clinical risk factors, which can accurately identify IC in ICU patients to give treatment on time and reduce mortality.

Risk factors for invasive candida infection in critically ill patients - a systematic review and meta-analysis

Background

Current guidelines recommend empirical antifungal therapy in patients with sepsis with high risk of invasive Candida infection. However, many different risk factors have been derived from multiple studies. These risk factors lack specificity, and broad application would render most ICU patients eligible for empirical antifungal therapy.

Research Question

What risk factors for invasive Candida infection can be identified by a systematic review and meta-analysis?

Study Design and Methods

We searched PubMed, Web of Science, ScienceDirect, Biomed Central, and Cochrane and extracted the raw and adjusted OR for each risk factor associated with invasive Candida infection. We calculated pooled ORs for risk factors present in more than one study.

Results

We included 34 studies in our meta-analysis resulting in the assessment of 29 possible risk factors. Risk factors for invasive Candida infection included demographic factors, comorbid conditions, and medical interventions. Although demographic factors do not play a role for the development of invasive Candida infection, comorbid conditions (eg, HIV, Candida colonization) and medical interventions have a significant impact. The risk factors associated with the highest risk for invasive Candida infection were broad-spectrum antibiotics (OR, 5.6; 95% CI, 3.6-8.8), blood transfusion (OR, 4.9; 95% CI, 1.5-16.3), Candida colonization (OR, 4.7; 95% CI, 1.6-14.3), central venous catheter (OR, 4.7; 95% CI, 2.7-8.1), and total parenteral nutrition (OR, 4.6; 95% CI, 3.3-6.3). However, dependence between the various risk factors is probably high.

Interpretation

Our systematic review and meta-analysis identified patient- and treatment-related factors that were associated with the risk for the development of invasive Candida infection in the ICU. Most of the factors identified were either related to medical interventions during intensive care or to comorbid conditions.

Assessment of Total Parenteral Nutrition administration among Intensive Care Unit patients at Omdurman Military Hospital, Sudan.. [DOI: 10.1101/2020.10.19.20215053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Total parenteral nutrition is one of the important types of nutrition among patients with intestinal failure. This research was intended to assess total parenteral nutrition administration of the intensive care unit patients at the Military hospital, Sudan. A cross-sectional hospital-based study assessed the patients records in the period between April 2014-November 2015, data were analyzed through chi-square test, it was considered significant when p≤ 0.05. Twenty patients who received total parenteral nutrition were assessed, 60% were males, while 40% were females. The most frequent indication for total parenteral nutrition was laparotomy (35% of patients). The duration of total parenteral nutrition was assessed, 70% of patients had duration between 1-20 days. Regarding total parenteral nutrition complications, the most frequent complication was hypokalemia (45% of patients), refeeding syndrome occurred in 10 % of patients. A statistically significant association was found between total parenteral nutrition duration when assessed with age and indication (p= 0.005 and 0.000 respectively). Patients suffering from electrolytes imbalance need more care to avoid the development of refeeding syndrome, as well as high level of hygiene is strictly required to overcome septic complications. There is a need to consider specialized care team composed of nurses, clinical pharmacists and nutritionists.

Catheter-related bloodstream infections in palliative care patients receiving parenteral nutrition by medical home care

BACKGROUND

Catheter-related bloodstream infections (CRBSIs) constitute a major complication associated with the use of central venous lines (CVL). The aim of this study was to investigate the incidence proportion and risk factors of CRSBI in palliative care patients with CVL receiving home parenteral nutrition (HPN).

METHODS

Medical records from patients admitted to a medical home care unit in stockholm, Sweden, during 2017 were reviewed (n=1022) and 454 palliative care patients with a CVL were identified. Data on CRBSI cases, HPN exposure time, type of parenteral nutrition (PN), age, diagnosis and type of CVL were collected.

RESULTS

Twenty-nine of 143 patients receiving HPN through a CVL were diagnosed with a CRBSI (20%). Nine of 311 patients with CVL without exposure for HPN developed CRBSI (3%). The risk of a CRBSI was significantly higher in patients receiving HPN compared with those not receiving HPN, OR 8.5 (95% CI 4.0 to 18.7). For those receiving HPN six to seven times a week the risk was even higher, OR 13 (95% CI 5.1 to 30.3). The highest incidence proportion of CRBSI (31%) was found in a home care team where patients had been trained to disconnect themselves from the PN drip. Sex, cancer versus non-cancer, type of CVL or protein content in the PN, did not differ between patients that developed CRBSI versus those that did not develop the outcome.

CONCLUSION

HPN entails a high risk of CRBSI. A high frequency of PN and incautious handling of the disconnection of the drip, seem to be the most important risk factors.

Bactericidal and Antiproliferative Effects of Peripheral Parenteral Nutrition Solutions with Sodium Bisulfite on Pathogenic Microorganisms in Catheter Lumens

Catheter-related bloodstream infections (CRBSIs) due to pathogenic microorganisms pose a major threat to patients requiring parenteral nutrition (PN). Additives contained in medicines and foods have antiproliferative and bacteriostatic effects on pathogenic microorganisms. Therefore, PN solutions containing additives may also have an antibacterial effect. However, so far, there have been no reports on or observations of a PN solution with bactericidal activity. In this study, we assessed several nutrition solutions with antimicrobial activities and investigated their effects on pathogenic microorganisms colonizing catheter lumens. We selected the highly acidic Plas-Amino^® (PA), which contains a large amount of sodium bisulfite as a preservative and potentially has an antimicrobial effect. In this study, we used the following pathogenic bacteria as the main causatives of CRBSIs: Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Serratia marcescens, Pseudomonas aeruginosa, and Candida albicans. We then created a catheter lumen microorganism contamination model and evaluated the antibacterial effect of PA; we found that all bacteria in the control group grew significantly in the catheter lumen in a time-dependent manner at 48 and 72 h. On the other hand, we demonstrated that PA has bactericidal effects on S. aureus, S. epidermidis, B. cereus, S. marcescens, and P. aeruginosa in the catheter lumen and confirmed that it has a remarkable antiproliferative effect on C. albicans. Hence, we concluded that highly acidic PN solutions that contain a preservative like sodium bisulfite have bactericidal and growth inhibition effects on microorganisms in the catheter lumens of patients with CRBSIs and patients with totally implantable central venous access devices, in whom it is difficult to remove the catheter.

Microbial Contamination of Neonatal Injectable Lipid Emulsions at 12 and 24 Hours' Infusion Time With Evaluation of Infection Control Measures

OBJECTIVES

This study aimed to assess the microbial contamination rate of injectable lipid emulsion (ILE) repackaged syringes at 12 and 24 hours of their infusion time. Probable risk factors associated with contamination of the ILEs were also assessed. In addition, the antimicrobial resistance pattern of the bacterial isolates was also determined.

METHODS

Samples of ILE were collected from 152 repackaged syringes and their infusion lines after 12 hours and 24 hours of infusion time (73 and 79 samples, respectively). Samples were cultured, the isolates were identified, and the antimicrobial resistance pattern of the bacterial isolates was identified. A checklist was completed throughout the study to observe the compliance to infection control measures by pharmacists (who prepare) and nurses (who administer) the ILE infusions. Results of septic neonatal cultures were taken from records.

RESULTS

Microbial contamination was found in 15.8% of ILE samples. The 2 most common pathogens found among positive samples were Klebsiella pneumoniae (29.2%) and Candida albicans (20.8%). Microbial contamination of repackaged syringes increased from 9.6% at 12 hours to 21.5% at 24 hours. This difference was found to be statistically significant (p = 0.044). A similar trend of predominance of those 2 pathogens, in both ILE and neonatal cultures, was observed. There was a statistically significant better performance of infection control measures of pharmacists rather than nurses. The K pneumoniae isolates (n = 7) showed antibiotic resistance in the following pattern: gentamicin (71.4%), cefazolin (85.7%), and cefoxitin (85.7%).

CONCLUSIONS

The rate of ILE contamination was less at 12 hours' than at 24 hours' infusion time. However, contamination rates at 12 hours were unacceptably high. Klebisella pneumoniae and C albicans were the most common pathogens isolated from ILE. Compliance with infection control measures was significantly worse among nurses compared with pharmacists.

Disparate Candida albicans Biofilm Formation in Clinical Lipid Emulsions Due to Capric Acid-Mediated Inhibition

Receipt of parenteral nutrition (PN) remains an independent risk factor for developing catheter-related bloodstream infections (CR-BSI) caused by fungi, including by the polymorphic fungus Candida albicans, which is notoriously adept at forming drug-resistant biofilm structures. Among a variety of macronutrients, PN solutions contain lipid emulsions to supply daily essential fats and are often delivered via central venous catheters (CVCs). Therefore, using an in vitro biofilm model system, we sought to determine whether various clinical lipid emulsions differentially impacted biofilm growth in C. albicans We observed that the lipid emulsions Intralipid and Omegaven both stimulated C. albicans biofilm formation during growth in minimal medium or a macronutrient PN solution. Conversely, Smoflipid inhibited C. albicans biofilm formation by approximately 50%. Follow-up studies revealed that while Smoflipid did not impair C. albicans growth, it did significantly inhibit hypha formation and hyphal elongation. Moreover, growth inhibition could be recapitulated in Intralipid when supplemented with capric acid-a fatty acid present in Smoflipid but absent in Intralipid. Capric acid was also found to dose dependently inhibit C. albicans biofilm formation in PN solutions. This is the first study to directly compare different clinical lipid emulsions for their capacity to affect C. albicans biofilm growth. Results derived from this study necessitate further research regarding different lipid emulsions and rates of fungus-associated CR-BSIs.

Blood gas sample spiking with total parenteral nutrition, lipid emulsion, and concentrated dextrose solutions as a model for predicting sample contamination based on glucose result

OBJECTIVE

Evaluate the effects of blood gas sample contamination with total parenteral nutrition (TPN)/lipid emulsion and dextrose 50% (D50) solutions on blood gas and electrolyte measurement; and determine whether glucose concentration can predict blood gas sample contamination with TPN/lipid emulsion or D50.

DESIGN AND METHODS

Residual lithium heparin arterial blood gas samples were spiked with TPN/lipid emulsion (0 to 15%) and D50 solutions (0 to 2.5%). Blood gas (pH, pCO2, pO2), electrolytes (Na+, K+ ionized calcium) and hemoglobin were measured with a Radiometer ABL90. Glucose concentration was measured in separated plasma by Roche Cobas c501. Chart review of neonatal blood gas results with glucose >300 mg/dL (>16.65 mmol/L) over a seven month period was performed to determine whether repeat (within 4 h) blood gas results suggested pre-analytical errors in blood gas results. Results were used to determine whether a glucose threshold could predict contamination resulting in blood gas and electrolyte results with greater than laboratory-defined allowable error.

RESULTS

Samples spiked with 5% or more TPN/lipid emulsion solution or 1% D50 showed glucose concentration >500 mg/dL (>27.75 mmol/L) and produced blood gas (pH, pO₂, pCO₂) results with greater than laboratory-defined allowable error. TPN/lipid emulsion, but not D50, produced greater than allowable error in electrolyte (Na⁺,K⁺,Ca⁺⁺,Hb) results at these concentrations. Based on chart review of 144 neonatal blood gas results with glucose >250 mg/dL received over seven months, four of ten neonatal intensive care unit (NICU) patients with glucose results >500 mg/dL and repeat blood gas results within 4 h had results highly suggestive of pre-analytical error. Only 3 of 36 NICU patients with glucose results 300-500 mg/dL and repeat blood gas results within 4 h had clear pre-analytical errors in blood gas results.

CONCLUSION

Glucose concentration can be used as an indicator of significant blood sample contamination with either TPN/lipid emulsion or D50 solution. NICU blood gas samples with glucose ≥300 mg/dL should be considered potentially contaminated, and samples with glucose >500 mg/dL have a risk for contamination.

Risk factors of catheter-related bloodstream infection caused by Bacillus cereus: Case-control study in 8 teaching hospitals in Japan

In this multicenter, matched case-control study, patients diagnosed with catheter-related bloodstream infection (CRBSI) caused by Bacillus cereus (n = 108) were matched to controls (n = 269). In the multivariable analysis, administration of an amino acid preparation and an indwelling peripheral catheter were significant variables for B cereus-related CRBSI.

Candida albicans outbreak associated with total parenteral nutrition in the neonatal unit

BACKGROUND

The most frequently isolated fungi in patients using TPN belongs to the Candida genus. Various infections including venous catheter infections, fungemia, endocarditis and ophthalmitis may be encountered.

OBJECTIVE

Upon growth of Candida in the blood cultures from the pediatric (neonatal) unit of our hospital, a surveillance was performed in this unit and involving the health care workers. Clonal relationships of the isolates were investigated with molecular tests.

METHODS

Blood samples obtained from the patients in pediatric neonatal unit were studied with automatized blood culture [BacT/Alert (Bio Mιrioux, France)]. Yeast isolates from environmental surveillance cultures (TPN solutions, hands of healthcare personnel, ιtagθre, etc) and patients were identified as C. albicans with conventional methods and ID 32 C and ATB TM Fungus 3 (Biomerieux, France) kits. Clonal similarity was determined by using AP-PCR as initial method and we have also typified all strains by the method of REP-PCR (diversilab system,bioMιrieux). Finally; Pulsed Field Gel Electrophoresis (PFGE) was used for confirmation.

RESULTS

C. albicans was isolated in blood cultures of seven patients. Similar antifungal susceptibility patterns were observed in all isolates. AP-PCR and REP-PCR showed that the C. albicans isolates grown in the TPN solution and from the patients' blood cultures were clonally same strains. PFGE analysis further confirmed this clonality.

CONCLUSION

According to results of the molecular methods, we thought that a C. albicans outbreak had occurred in the neonatal pediatric unit, due to contamination of TPN solution.

Systematic review and meta-analyses of the effect of lipid emulsion on microbial growth in parenteral nutrition

BACKGROUND

As lipid in parenteral nutrition (PN) purportedly enhances microbial growth, recommendations limit infusion of lipid PN (or lipid emulsion) from a single container to 24h (48h for lipid-free PN). However, the associated evidence base is ambiguous.

AIM

To examine factors affecting microbial growth in PN.

METHODS

A systematic review with meta-analyses examined effects of nutrients on microbial growth in PN infusates over a 48-h period using the growth ratio {GR=log₁₀[colony-forming units (cfu)/mL at 48h/cfu/mL at time zero]}.

FINDINGS

Factors influencing GR in PN included glucose, microbial species, temperature, osmolarity, presence of vitamins, trace elements and lipid, and amino acid profile. Using unmatched datasets (N=306), a general linear model found that lipid inclusion in PN represented 3.3% of the variability, which was less than that due to glucose concentration (5.8%), microbial species (35.3%) and microbe-infusate interaction (4.4%). Using matched datasets (N=38 pairs), lipid inclusion in PN represented 5.4% of the variability (P=0.076), which was less than that due to glucose concentration (8.5%; P=0.025), microbial species (75.5%; P<0.001) and microbe-infusate interaction (13.3%; P=0.382). Using meta-analyses of matched datasets, the presence of lipid in PN at fixed glucose concentrations did not significantly increase GR of Candida albicans, Escherichia coli or Staphylococcus epidermidis (P=0.352, P=0.025 and P=0.494, respectively; overall P=0.175).

CONCLUSION

Lipid inclusion in PN is only one of several factors that may influence microbial growth in PN. Any recommendations about the duration of PN infusion from a single container should account for all these factors, and should be weighted according to microbial species likely to contaminate PN.

Adding Biotin to Parenteral Nutrition Solutions Without Lipid Accelerates the Growth of Candida albicans

BACKGROUND

We have previously demonstrated that Candida albicans requires multivitamins (MVs) or lipid to increase rapidly in parenteral nutrition (PN) solutions. In this study, in detail, the effects of vitamins on the growth of C. albicans in PN solutions without lipid were investigated.

METHODS

In the 1st experiment, a commercial PN solution without lipid was supplemented with water-soluble vitamins (SVs: vitamins B1, B2, B6, B12 and C, folic acid, nicotinamide, biotin and panthenol), water-insoluble vitamins (IVs: vitamins A, D, E and K) or both (MVs). In the 2nd experiment, the test solutions were prepared by supplementing the PN solution with one of each or all of the SVs. In the 3rd experiment, another commercial peripheral PN (PPN) solution without lipid was supplemented with SVs, nicotinic acid, biotin or both nicotinic acid and biotin. In each of the experiments, a specified number of C. albicans organisms was added to each test solution, and all of the test solutions were allowed to stand at room temperature (23-26ºC). The number of C. albicans was counted at 0, 24, 48 and 72 hours after the addition of the organism.

RESULTS

In the 1st experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs, but increased slowly without the SVs, regardless of the addition of the IVs. In the 2nd experiment, the C. albicans increased rapidly in the PN solution supplemented with the SVs or biotin, but increased slowly with each of the other water-soluble vitamins. In the 3rd experiment, the C. albicans increased rapidly in the PPN solution supplemented with the SVs or biotin, but increased slowly with the addition of nicotinic acid.

CONCLUSIONS

These results suggested that adding MVs or SVs to PN solutions without lipid promotes the growth of C. albicans, and that this effect is mostly attributable to biotin.

Nutritional support in critical illness and recovery

An adequate nutritional status is crucial for optimum function of cells and organs, and for wound healing. Options for artificial nutrition have greatly expanded in the past few decades, but have concomitantly shown limitations and potential side-effects. Few rigorous randomised controlled trials (RCTs) have investigated enteral or parenteral nutritional support, and evidence-based clinical guidance is largely restricted to the first week of critical illness. In the early stages of critical illness, whether artificial feeding is better than no feeding intervention has been given little attention in existing RCTs. Expected beneficial effects of various forms of early feeding interventions on rates of morbidity or mortality have generally not been supported by results of recent high-quality RCTs. Thus, whether nutritional interventions early in an intensive care unit (ICU) stay improve outcomes remains unclear. Trials assessing feeding interventions that continue after the first week of critical illness and into the post-ICU and post-hospital settings are clearly needed. Although acute morbidity and mortality will remain important safety parameters in such trials, primary outcomes should perhaps, in view of the adjunctive nature of nutritional intervention in critical illness, be focused on physical function and assessed months or even years after patients are discharged from the ICU. This Series paper is based on results of high-quality RCTs and provides new perspectives on nutritional support during critical illness and recovery.

Laboratory replication of filtration procedures associated with Serratia marcescens bloodstream infections in patients receiving compounded amino acid solutions

PURPOSE

Specific deviations from United States Pharmacopeia standards were analyzed to investigate the factors allowing an outbreak of Serratia marcescens bloodstream infections in patients receiving compounded amino acid solutions.

METHODS

Filter challenge experiments using the outbreak strain of S. marcescens were compared with those that used the filter challenge organism recommended by ASTM International (Brevundimonas diminuta ATCC 19162) to determine the frequency and degree of organism breakthrough. Disk and capsule filters (0.22- and 0.2-μm nominal pore size, respectively) were challenged with either the outbreak strain of S. marcescens or B. diminuta ATCC 19162. The following variables were compared: culture conditions in which organisms were grown overnight or cultured in sterile water (starved), solution type (15% amino acid solution or sterile water), and filtration with or without a 0.5-μm prefilter.

RESULTS

Small-scale, syringe-driven, disk-filtration experiments of starved bacterial cultures indicated that approximately 1 in every 1,000 starved S. marcescens cells (0.12%) was able to pass through a 0.22-μm nominal pore-size filter, and about 1 in every 1,000,000 cells was able to pass through a 0.1-μm nominal pore-size filter. No passage of the B. diminuta ATCC 19162 cells was observed with either filter. In full-scale experiments, breakthrough was observed only when 0.2-μm capsule filters were challenged with starved S. marcescens in 15% amino acid solution without a 0.5-μm prefiltration step.

CONCLUSION

Laboratory simulation testing revealed that under certain conditions, bacteria can pass through 0.22- and 0.2-μm filters intended for sterilization of an amino acid solution. Bacteria did not pass through 0.2-μm filters when a 0.5-μm prefilter was used.

Addition of lipids to parenteral nutrition does not cause fungal infections

Parenteral nutrition (PN) that includes lipid emulsion is considered to increase both bacterial and fungal central venous catheter-related bloodstream infections. This concept is based on several erroneous metrics: Reports in age-old literature at a time when preparing PN admixtures lacked stringent quality control, when its infusion, the techniques of insertion, maintenance of vascular access devices, and delivery systems were not well identified or enforced. Additionally, concepts of glucohomeostasis were different and higher glucose levels were accepted. We provide updated information with supporting literature to show that associating PN with lipids with an increase in bloodstream infections is not justified.

Outbreak of Serratia marcescens bloodstream infections in patients receiving parenteral nutrition prepared by a compounding pharmacy

BACKGROUND

Compounding pharmacies often prepare parenteral nutrition (PN) and must adhere to rigorous standards to avoid contamination of the sterile preparation. In March 2011, Serratia marcescens bloodstream infections (BSIs) were identified in 5 patients receiving PN from a single compounding pharmacy. An investigation was conducted to identify potential sources of contamination and prevent further infections.

METHODS

Cases were defined as S. marcescens BSIs in patients receiving PN from the pharmacy between January and March 2011. We reviewed case patients' clinical records, evaluated pharmacy compounding practices, and obtained epidemiologically directed environmental cultures. Molecular relatedness of available Serratia isolates was determined by pulsed-field gel electrophoresis (PFGE).

RESULTS

Nineteen case patients were identified; 9 died. The attack rate for patients receiving PN in March was 35%. No case patients were younger than 18 years. In October 2010, the pharmacy began compounding and filter-sterilizing amino acid solution for adult PN using nonsterile amino acids due to a national manufacturer shortage. Review of this process identified breaches in mixing, filtration, and sterility testing practices. S. marcescens was identified from a pharmacy water faucet, mixing container, and opened amino acid powder. These isolates were indistinguishable from the outbreak strain by PFGE.

CONCLUSIONS

Compounding of nonsterile amino acid components of PN was initiated due to a manufacturer shortage. Failure to follow recommended compounding standards contributed to an outbreak of S. marcescens BSIs. Improved adherence to sterile compounding standards, critical examination of standards for sterile compounding from nonsterile ingredients, and more rigorous oversight of compounding pharmacies is needed to prevent future outbreaks.

Microbial Growth in Neonatal Intravenous Fat Emulsion Administered Over 12 Versus 24 Hours

OBJECTIVES

To determine whether an extended infusion time (24 hours) of intravenous fat emulsion is associated with an increase in microbial growth, versus a shorter infusion time (12 hours).

METHODS

Samples were collected from intravenous fat emulsions (n=132), from intravenous fat emulsions prepared in the current 24-hour infusion method (n=55), and from intravenous fat emulsions prepared in the twice-daily (12-hour infusion) method (n=55). In addition, samples were collected from pharmacy (n=22) to test for possible contamination.

RESULTS

No growth was observed in either arm of the study.

CONCLUSIONS

Current Kern Medical Center policy of preparation and administration of neonatal intensive care unit intravenous fat emulsion is safe and effective in regard to microbial growth.

Standardised parenteral nutrition

Parenteral nutrition (PN) has become an integral part of clinical management of very low birth weight premature neonates. Traditionally different components of PN are prescribed individually considering requirements of an individual neonate (IPN). More recently, standardised PN formulations (SPN) for preterm neonates have been assessed and may have advantages including better provision of nutrients, less prescription and administration errors, decreased risk of infection, and cost savings. The recent introduction of triple-chamber bag that provides total nutrient admixture for neonates may have additional advantage of decreased risk of contamination and ease of administration.

Effects of lipid emulsion and multivitamins on the growth of microorganisms in peripheral parenteral nutrition solutions

BACKGROUND

Blood stream infections caused by Bacillus cereus or Serratia marcescens in patients receiving peripheral parenteral nutrition (PPN) have occasionally been reported in Japan, but these microorganisms are not major causes of blood stream infections in patients receiving total parenteral nutrition via a central venous catheter. In Japan, commercially available PPN solutions contain amino acids, glucose, and electrolytes, but not contain lipid emulsion (LE) and multivitamins (MV). In this study, the effects of LE and MV on the growth of microorganisms such as Bacillus cereus, Serratia marcescens, Staphylococcus aureus, and Candida albicans in PPN solutions were investigated.

METHODS

A commercial 3% amino acid and 7.5% glucose solution with electrolytes (AF) was used as the base solution to prepare test solutions (LAF, AFV, and LAFV) containing LE, MV, or both. Specifically, 20% LE was added to AF in a ratio of 1:9 to prepare LAF. MV was added to AF and LAF to prepare AFV and LAFV, respectively. A specified number of each microorganism was added to each 100 mL of AF, LAF, AFV, and LAFV in sterile plastic flasks, and all flasks were allowed to stand at room temperature. The number of colony forming units per mL of each microorganism was counted at 0, 24, and 48 hours after the addition of each microorganism.

RESULTS

Both Bacillus cereus and Serratia marcescens increased rapidly in AF as well as in LAF, AFV, and LAFV. Staphylococcus aureus did not increased in AF, but increased slightly in LAF and increased rapidly in AFV and LAFV. Candida albicans increased slightly in AF and increased rapidly in LAF, AFV, and LAFV.

CONCLUSIONS

The results suggest the followings: if microbial contamination occurs, 1) Bacillus cereus and Serratia marcescens can grow rapidly in PPN solutions consisting of amino acids, glucose and electrolytes; 2) Staphylococcus aureus cannot grow without LE and MV, but can grow rapidly with MV; 3) Candida albicans can grow slowly without LE and MV, and the addition of LE or MV accelerates its growth.

Risk of parenteral nutrition in neonates--an overview

Healthcare-associated infections (HAI) in preterm infants are a challenge to the care of these fragile patients. HAI-incidence rates range from 6 to 27 infections per 1000 patient-days. Most nosocomial infections are bloodstream infections and of these, the majority is associated with the use of central venous catheters. Many studies identified parenteral nutrition as an independent risk factor for HAI, catheter-associated bloodstream infection, and clinical sepsis. This fact and various published outbreaks due to contaminated parenteral nutrition preparations highlight the importance of appropriate standards in the preparation and handling of intravenous solutions and parenteral nutrition. Ready-to-use parenteral nutrition formulations may provide additional safety in this context. However, there is concern that such formulations may result in overfeeding and necrotizing enterocolitis. Given the risk for catheter-associated infection, handling with parenteral nutrition should be minimized and the duration shortened. Further research is required about this topic.

Factors that influence Staphylococcus epidermidis growth in parenteral nutrition with and without lipid emulsion: a study framework to inform maximum duration of infusion policy decisions

BACKGROUND & AIMS

Recommendations limit infusion of parenteral nutrition (PN) from bags with lipid to 24 h (48 h if lipid free) because lipid putatively encourages contaminant growth. This study aimed to examine these recommendations and identify factors affecting Staphylococcus epidermidis growth in PN.

METHODS

S. epidermidis growth was assessed in quadruplicate in 12 PN regimens, with and without lipid and varying glucose concentrations.

RESULTS

Baseline colony forming units (cfu)/mL (32.6) less than doubled at 48 h in all infusates. In PN infusates (pH 6.2 + 0.02 (SEM)) growth was independently increased by the presence of 5% w/v lipid (14.2 cfu/mL; P = 0.028), and glucose concentration (25.6 cfu/mL per 10% increase in w/v glucose; P = 0.003). In a separate analysis growth was stimulated by energy density (27.7 cfu/1000 kcal non-nitrogen energy in 2 L; P = 0.002), without a significant effect of % non-protein energy from lipid (-2.6 cfu/ml per 10%).

CONCLUSIONS

Using a framework developed to examine growth of potential contaminants in PN, no evidence was found to support the specific recommendation to restrict the maximum infusion duration of lipid containing PN to a greater extent than lipid free PN. S. epidermidis growth was not only affected by the presence of lipid, but also glucose concentration and energy density.

Severe Candida spp. infections: new insights into natural immunity

Invasive infections caused by Candida spp. are associated with high mortality. Colonisation by Candida spp. and the capacity of the host to recognise them as potential pathogens are essential steps in the development of these infections. The major pathogen-associated molecular patterns of Candida are mannoproteins, glucans and chitins, which are recognised by C-type lectin pattern recognition receptors such as the mannose receptor, dectin-1 and dectin-2. By the secretion of proteases and toxins, and the formation of hyphae and biofilms, Candida spp. are able to enhance their virulence and pathogenicity. Studies in patients with relatively rare immunodeficiencies, such as dectin-1 deficiency, CARD9 deficiency, chronic mucocutaneous candidiasis, hyper-IgE/Job's syndrome and chronic granulomatous disease, have shown the role of dectin-1 and its signalling pathway, which involves interleukins 17 and 22, defensins and phagocytic cells, in defence against Candida. These studies also provide insights into how acquired risk factors for fungal infection operate, and may lead to new approaches for immunotherapy.