Microbial contamination of enteral feeding solutions in a community hospital

Blenderized Tube Feedings for Adult Patients on Home Enteral Nutrition: A Pilot Study

OBJECTIVE

Despite surveys indicating a high prevalence of blenderized tube feeding (BTF) as an alternative to commercial enteral nutrition (EN), there remains a paucity of data regarding use in clinical practice. The objective of the present open-label pilot study was to assess the safety and effectiveness of BTF in adult patients being given home enteral nutrition (HEN).

DESIGN

This is an open-label pilot study, in which all participants who had been on traditional EN formulas were changed to BTF for 6 weeks.

SETTING/LOCATION

The Mayo Clinic in Rochester, Minnesota.

PARTICIPANTS

Twenty individuals gave their consent to participate in the study, with nine completing the 6-week BTF protocol.

OUTCOME MEASURES

Weight was measured at baseline and at 6 weeks of BTF use. Participants completed a survey regarding the frequency of BTF use and adverse effects, at baseline and then weekly for 6 weeks.

RESULTS

Nine participants with a mean age of 60.6 ± 7.8 years completed the 6-week protocol. BTF use increased from 4.85 ± 2.44 to 6.45 ± 0.82 days per week from week 1 to week 6. The percentage of participants consuming >50% of their calorie intake from BTF increased from 23.1% (3 of 13 participants) at week 1 to 44.4% (4 of 9 participants) at week 6. Six of nine participants experienced weight gain, weight was maintained by one participant, and two participants lost weight (intentionally in one and due to an intolerance of commercial formula in the other).

CONCLUSIONS

BTF was found to be safe and effective in promoting weight gain in adult participants who required HEN for at least 6 weeks.

A Microbiologic Study of Enteral Feeding Hang Time in a Burn Hospital: Can Feeding Costs be Reduced Without Compromising Patient Safety?

BACKGROUND

Procedural changes for hospitalized patients must always balance safety with fiscal constraints. Microbiologic contamination of enteral feeding solutions has been previously associated with nosocomial infections. Formula manipulation and hang time contribute to microbial load, and there is considerable variation in hang time recommendations in the medical literature. With cost containment in mind, the purpose of this performance improvement study was to determine if an increase in hang time of a modular tube feeding product would increase microbial load or affect the nosocomial infection rate in pediatric burn patients.

METHODS

This biphasic trial initially evaluated the microbial load of the feeding after delivery of two 4-hour aliquots into a container using the same delivery set (total hang time of 8 hours; number of tests = 20). Second, once this feeding procedure was deemed microbiologically safe, tube feedings were administered to patients, and both microbial load and nosocomial infection rate were monitored for 1 year.

RESULTS

Contamination levels at the end of the 8-hour period using the same feeding set with 2 consecutive 4-hour feeding aliquots (number of tests = 38) were lower than standard recommendations. The hospital's nosocomial infection rate was not altered by this procedural change, and feeding-set expenses were reduced.

CONCLUSIONS

The hang time of our enteral feeding administration set can be increased safely from 4 hours to 8 hours, with the tube feeding preparation added as two 4-hour aliquots without a significant change in microbial load or nosocomial infection rate, thus promoting simultaneous fiscal responsibility and patient safety.

ASPEN Safe Practices for Enteral Nutrition Therapy [Formula: see text]

Enteral nutrition (EN) is a valuable clinical intervention for patients of all ages in a variety of care settings. Along with its many outcome benefits come the potential for adverse effects. These safety issues are the result of clinical complications and of process-related errors. The latter can occur at any step from patient assessment, prescribing, and order review, to product selection, labeling, and administration. To maximize the benefits of EN while minimizing adverse events requires that a systematic approach of care be in place. This includes open communication, standardization, and incorporation of best practices into the EN process. This document provides recommendations based on the available evidence and expert consensus for safe practices, across each step of the process, for all those involved in caring for patients receiving EN.

Use of Blenderized Tube Feeding in Adult and Pediatric Home Enteral Nutrition Patients

BACKGROUND

Long-term use of enteral nutrition (EN) continues to increase due to significant noted benefits. Patients also continue to express significant desire to pursue holistic and organic diets. Despite this, many nutrition providers are not well versed in assisting patients with blenderized tube feeding (BTF), and prevalence of its use is unknown.

METHODS

A validated survey was administered to Oley Foundation members or individuals with access to the Oley website to assess the prevalence of BTF.

RESULTS

A total of 216 participants took the survey, of whom 125 (57.8%) were pediatric patients with a mean age of 5.4 ± 3.5 years and 91 (42.2%) were adults with a mean age of 51.7 ± 19.5 years. Of pediatric patients, 112 (89.6%) used BTF for an average of 71% of their total daily nutrition intake; 93 (83%) reported that BTF comprised >50% of their daily EN, 12 (10.7%) reported it comprised 25%-50% of their daily enteral intake, and 7 (6.3%) reported BTF comprised < 25% of their daily intake. In the adult population, 60 (65.9%) used BTF for an average of 56% of total daily nutrition intake; 41 (68.4%) reported BTF comprised >50% of their daily nutrition intake, 11 (18.3%) reported it compromised 25%-50%, and 8 (13.3%) reported BTF comprised <25% of their daily intake.

CONCLUSIONS

Most of the pediatric and adult patients surveyed use BTF as some portion of their enteral intake, making it essential that clinicians expand their knowledge related to BTF to appropriately care for this patient population.

Nutrition and Nutritional Support in Critically Ill Patients

The use of intravenous nutritional support has increased dramatically in the last 20 years. Although it is not without controversy, administration of nutritional support is common practice in hospitalized patients including critically ill patients. Malnutrition continues to be reported in a significant number of hospitalized patients. The incidence of malnutrition in critically ill patients may be even higher than that reported in hospitalized patients overall. The consequences of malnutrition in a critically ill patient may be severe. Nutritional assessment and nutritional support can present special challenges to the intensivist. Techniques of nutritional assessment in critically ill patients are evaluated. Guidelines for the determination of the nutritional needs of these patients are outlined. Methods of delivery of nutritional support in critically ill patients are reviewed. Complications of nutritional support are discussed.

Enterobacter sakazakii Infections in Neonates Associated with Intrinsic Contamination of a Powdered Infant Formula

We report an outbreak of Enterobacter sakazakii infection and colonization in neonates related to an infant formula contaminated during the manufacturing process. The outbreak occurred in a 2O-bed neonatal intensive care unit during a six-week period in 1988, and involved a total of four infants. Three infants had sepsis and three had bloody diarrhea; all patients responded to intravenous antibiotics and recovered without complications. The E sakazakii isolated from the formula had the same plasmid and multilocus enzyme profile as those isolated from patients. This outbreak demonstrates the significance of commercially contaminated formulas and emphasizes the need to limit contamination and multiplication of bacteria in enteral formulas.

Blenderized Tube Feeding Use in Adult Home Enteral Nutrition Patients: A Cross-Sectional Study

BACKGROUND

Use of long-term enteral nutrition (EN) has increased dramatically in the United States. It has been the authors' experience that most home EN (HEN) patients use blenderized tube feeding (BTF) in addition to commercial EN. There are limited resources available for patients interested in BTF, and studies evaluating safety and effectiveness are limited.

METHODS

The authors conducted a prospective cross-sectional study (n = 54).

INCLUSION CRITERIA

age >18 years, follow-up in HEN clinic, prescribed commercial EN. Participants were provided the survey at HEN follow-up appointments after receiving HEN for at least 3 weeks.

RESULTS

Median age (range) was 60.5 (22-87) years with 42.6% females (n = 23). BTF was used by 55.5% of patients (n = 30). Most (57%; n = 31) received HEN for >6 months. BTF use was a median of 4 (1-7) days per week. Most common reasons for using BTF were as follows: it is more natural (43%), like eating what their family does (33%), and tolerate BTF better (30%). In patients who use BTF, 80% reported maintaining goal body weight. BTF resulted in significantly less reported nausea, vomiting, bloating, diarrhea, and constipation compared with commercial EN.

CONCLUSIONS

This is the first study to evaluate BTF use in an adult HEN population. More than 50% of our patients used and approximately 80% expressed a desire to use BTF if provided with adequate information. With new connection tube changes coming in the near future, adequate adapters for BTF need to be developed.

Analysis of sites of bacterial contamination in an enteral feeding system

BACKGROUND

Contamination of enteral feedings is an often overlooked source for bacterial infection in the intensive care unit. A new 1-L enteral feeding system with minimal chances of touching critical areas (Nutrison Pack) was compared with routinely used 0.5-L glass bottle systems.

METHODS

Patients admitted to intensive care were randomized to Pack or glass bottle feeding systems. Cultures were taken from the delivery sets 5 times during the day and from feeding containers and different sites of the system after 24 hours.

RESULTS

Bacteria were present in 3 of 112 glass bottles and in 2 of 95 Pack bags. True bacterial contamination (defined as >10(2) colony-forming units/mL, with same bacteria also present in the delivery set) was found in none of the Packs with a 12-h (69 Packs) or a 24-h (26 Packs) hanging time and in only 1 of the glass bottles with a hanging time of 24 hours, which exceeded the advised hanging time of 8 hours. In contrast, the contamination rate of delivery sets was 48%, with increasing bacterial counts over the day and 4 subsequent days. Bacteria mainly belonged to the group of potentially pathogenic bacteria (Enterobacteriaceae and Pseudomonaceae). They likely originated from throat, lungs, and stomach and grew into and along feeding tubes upwards until they reached the delivery set.

CONCLUSIONS

Prolonged hanging times of Pack bags were safe with respect to bacterial contamination. However, the bacterial safety of enteral feedings is more likely to be endangered by the endogenous route of contamination rather than exogenous contamination, as high bacterial counts were found in feeding tubes and delivery sets as a result of retrograde growth.

Enterobacter sakazakii: a coliform of increased concern to infant health

The first cases of neonatal meningitis believed to have been caused by Enterobacter sakazakii were reported in 1961. Prompted by several subsequent outbreaks of E. sakazakii infections in neonates and an increasing number of neonates in intensive care units being fed rehydrated powdered infant formula, considered to be a source of the pathogen, public health authorities and researchers are exploring ways to eliminate the bacterium or control its growth in dry infant formula, processing environments and formula preparation areas in hospitals. Reviewed here are advances in taxonomy and classification of E. sakazakii, methods of detecting, isolating and typing the bacterium, antibiotic resistance, clinical etiology and pathogenicity. Outbreaks of E. sakazakii infections in neonates and adults are summarized. Reports on the presence of E. sakazakii in clinical settings, the environment and foods and food processing facilities are reviewed. Tolerance of the pathogen to environmental stresses, its behavior in powdered and rehydrated infant formulae and hazard analysis and risk management are discussed. Research needs are presented.

Microbial contamination of enteral feed administration sets in a pediatric institution

BACKGROUND

Enteral feeding tubes have been associated with outbreaks of antimicrobial-resistant organisms, but the pathogenesis of this association has not been investigated. We hypothesized that the enteral feed administration sets become colonized externally by microbes grown from the enteral tube hub, and therefore serve as a reservoir of organisms that can be crosstransmitted.

METHODS

We conducted a prospective observational cohort pilot study, obtaining bacterial cultures from the external enteral feed administration set and from the hub of nasogastric, gastric, or gastrojejunal tubes in children receiving enteral feeding while hospitalized in a tertiary care pediatric hospital.

RESULTS

Thirty-six of 37 hubs cultured had bacterial growth. Twenty-nine of 36 administration sets (78%) sampled had at least 1 microbe isolated that was also cultured from the hub. No significant risk factors for colonization were identified.

CONCLUSIONS

Enteral feed administration sets are frequently colonized by organisms in the enteral tube hub. These sets can serve as a reservoir of organisms that can be crosstransmitted between patients. Adherence to Standard Precautions is critical when handling enteral feeding apparatuses.

Prospective study of the incidence and complications of bacterial contamination of enteral feeding in neonates

PURPOSE

The goal of this study was to determine incidence of, and complications resulting from, bacterial contamination of enteral feedings in neonates.

METHODS

A prospective study of 50 tube-fed neonates was conducted. Infants were bolus fed via an open gravity drained system; demographic and clinical data were gathered. The lumen of the tube was cultured quantitatively after 7 days. All organisms were isolated, identified, frozen, and stored to correlate with clinical cultures.

RESULTS

The 50 neonates were fed for a mean of 17.6 days each and represent 125 patient weeks (1 tube per patient per week). A total of 71 of 125 tubes were "contaminated" (>1,000 colony forming units [CFU]/mL), with a mean 908,173 CFU and 3 different bacteria types. Among formula-fed infants, feeding intolerance occurred in 24 of 32 weeks with contaminated tubes versus 0 of 44 weeks with noncontaminated tubes (P <.05). Contamination occurred in 41 of 48 weeks in patients on H2 antagonists versus 32 of 66 weeks in patients with normal gastric acidity (P <.05). Necrotizing enterocolitis developed in 7 patients; all were fed formula contaminated with greater than 100,000 CFU/mL of Gram-negative bacteria. Four required operation; intraoperative cultures found the same organism as cultured previously in the tube in all 4 infants.

CONCLUSION

Bacterial contamination of enteral feeding occurs frequently, causes significant feeding intolerance, and may contribute to NEC.

Bacterial contamination of blenderized whole food and commercial enteral tube feedings in the Philippines

Hospital-prepared tube feedings from four Philippine acute-care hospitals were analysed for microbial contamination. Two feedings were prepared on three separate days at each hospital. The tube feedings were either blended natural whole foods or a reconstituted commercial powdered nutritional product. Samples of each feeding were collected for coliform count and standard plate count at the time of preparation and at 1, 2 and 4 h after preparation after maintenance at room temperature (26-31 degrees C). At the time of preparation, mean coliform and standard plate counts for all samples were 10.3 most probable number per gram (MPN/g) and 7.4x10(4)colony-forming units per gram (cfu/g), respectively. Nine of 24 samples (38%) had coliform counts greater than 10 MPN/g, and 22/24 (92%) samples had standard plate counts greater than 10(3) cfu/g. There were significant increases in mean coliform and standard plate counts over 4 h (P=0.0005 and P=0.008, respectively). At 4 h after preparation, the mean coliform and standard plate counts were 18.2 MPN/g and 2.1x10(5) cfu/g, respectively. At this time, 18/24 (75%) samples had coliform counts greater than 10 MPN/g and 20/24 (83%) samples had standard plate counts greater than 10(5) cfu/g. The results of this study show that the microbial quality of the majority of the hospital-prepared enteral tube feedings analysed were not within published guidelines for safety.

The effect of system design on bacterial contamination of enteral tube feeds

The effect of recent changes in system design on the levels and incidence of bacterial contamination in enteral tube feeds was examined by comparing two different systems. Adult patients who had been identified as requiring enteral tube feeding were allocated to receive sterile, whole protein enteral feed from either 2 x 1000 mL triple foil laminated pouches (Nutrison Standard, Nutrison Pack, Nutricia Ltd, UK) attached to a Flocare 800 pack giving set or from 2 x 1000 mL rigid plastic bottles (Osmolite, Ross Ready-to-Hang, Abbott Laboratories, UK) connected to a Patrol Pump set. Samples of feed from the nutrient containers were sent for microbiological analysis each time the container was changed (12 and 24 h) and samples from the distal ends of giving sets after 24 h.Bacterial contamination was found in a significantly lower number of Nutrison Packs (14/120; 12%) as compared with Ross Ready-to-Hang containers (25/120; 21%) (Fisher's exact test, 1 tailed test, P > or = 0.05). However, both the level and frequency of contamination of the feed samples collected from the distal ends of the giving sets of both types of system were similar to each other but higher than those from the nutrient containers (57/120 contaminated giving sets as compared with 39/240 nutrient containers; P > or = 0.00001). On 32/120 patient days only the giving set samples were contaminated. The results highlight the important role that improvements in system design, such as the use of recessed spikes on giving sets have in reducing the risk of bacterial contamination of enteral tube feeds introduced due to faulty handling procedures, and further implicate retrograde spread of the patients' own flora as a source of contamination in the giving set.

Metoclopramide for preventing pneumonia in critically ill patients receiving enteral tube feeding: a randomized controlled trial

OBJECTIVE

To determine whether metoclopramide prevents nosocomial pneumonia in intensive care unit (ICU) patients receiving enteral feeding by a nasogastric tube.

DESIGN

Prospective, randomized, controlled trial.

SETTING

ICU of a university hospital.

PATIENTS

A total of 305 consecutive patients requiring placement of a nasogastric tube for >24 hrs.

INTERVENTIONS

Patients were randomized to receive either 10 mg of metoclopramide or placebo at 8-hr intervals through the nasogastric tube.

MEASUREMENTS AND MAIN RESULTS

A total of 174 patients received placebo and 131 received metoclopramide. Baseline characteristics in the two treatment groups were comparable. Of the 305 patients, 46 developed nosocomial pneumonia, which was 24 patients (13.7%) in the placebo group and 22 (16.8%) in the metoclopramide group (p > .05). Patients in the placebo group developed pneumonia earlier than patients receiving metoclopramide (4.46+/-1.72 days [mean +/- SD[rsqb] after ICU admission compared with 5.95+/-1.78 days; p = .006). Subgroup analysis showed that metoclopramide did not reduce the frequency rate of pneumonia in patients with tracheal intubation (19 [25.3%] of 75 patients receiving metoclopramide vs. 21 [21.2%] of 99 patients receiving placebo) or those receiving mechanical ventilation (17 [25.6%] of 58 patients receiving metoclopramide vs. 20 [29.3%] of 78 patients receiving placebo). The mortality rate also did not differ in the two treatments groups (56% in the metoclopramide group vs. 53% in the placebo group; p > .05).

CONCLUSIONS

Although metoclopramide delayed the development of nosocomial pneumonia, it did not decrease its frequency rate and had no effect on the mortality rate in critically ill patients receiving nasogastric enteral feeding.

Bacterial contamination of ready-to-use 1-L feeding bottles and administration sets in severely compromised intensive care patients

OBJECTIVE

In intensive care patients, enteral feeding requires sterile feedings because of infectious complications and adequate supplements to meet nutritional needs. Heretofore, prepacked, large-volume formula containers were developed, but bacterial contamination occurred in 4% to 15%. Our objective was to investigate the microbial contamination rate of 1-L feeding bottles and newly designed administration sets over hanging times of 24 hrs in the intensive care unit (ICU).

DESIGN AND SETTING

A prospective observational cohort study of patients admitted to the ICU of a university hospital.

PATIENTS

All consecutive patients fed via a nasojejunal tube for at least 4 days.

MEASUREMENTS

Cultures of feeding bottles, administration sets, and gastric and tracheobronchial aspirates at day 0, 1, 2, 4, and 7.

RESULTS

A total of 4% of feeding bottles and 74% of infusion sets contained >10(2) colony forming units (CFU)/mL. Gastric and bronchial aspirates were positive in 90% and 92%, respectively. Bacterial counts of feeding bottles were 10(2)-10(5) CFU/mL, and the main bacteria isolated included Enterobacter cloacae, Klebsiella oxytoca, and enterococci. One third of all cultured bacteria in feeding bottles, administration sets, stomach, and lungs belonged to the Enterobacteriaceae family, which was held responsible for the nosocomial infections in the ICU. None of the 1-L feeding bottles with a hanging time of 19-24 hrs was contaminated. Only bottles that had to be exchanged because of need for a faster rate of infusion proved to be contaminated, apparently without clinical consequences. With time and the increasing severity of disease, the administration sets became contaminated at an increasingly faster rate and with higher bacterial counts mainly through retrograde growth of endogenous bacteria. The final step of bottle contamination might have been the bacterial transfer by nurses' hands.

CONCLUSION

Despite an almost ideal design of the enteral nutrition delivery system, a 4% contamination rate of initially sterile feedings with clinically relevant bacteria and the fact that only manipulated systems showed bacterial growth are of concern.

Microbiological evaluation of four enteral feeding systems which have been deliberately subjected to faulty handling procedures

The present study was designed to investigate the levels of contamination in four currently used 1000 mL, 'ready-to-hang', enteral feeding systems--Osmolite (Ross Ready-To-Hang), Steriflo, Dripac-flex and Easybag, when faulty handling procedures were used during assembly of the systems. The top of the nutrient container and the proximal (container) end of the pump set of each system were touched during assembly by a researcher whose hands had been deliberately contaminated with Klebsiella aerogenes. Once assembled systems were run continuously for 24 h delivering 1000 mL of feed. Feed samples for microbiological analysis were taken from the distal (patient) end of the feeding tube at 0 h and 24 h and from the feed remaining in the nutrient container at the end of administration (24 h). Five systems of each type were run. Five controls were also run for each type of system, where all procedures were carried out wearing sterile gloves. Eighty-seven percent of feed samples collected from the Osmolite systems and 80% of those from the Steriflo systems were found to contain K. aerogenes, with 13% of feed samples from both systems containing > or = 10(4) cfu/mL, a level of contamination, considered by many, as that above which feed is unacceptable for patient consumption. The percentage of feed systems containing the test organism was much lower in the Dripac-flex and Easybag systems, with K. aerogenes being detected in 27% and 13% of samples respectively. No feed samples from either of these systems contained > or = 10(4) cfu/mL. From the results it can be concluded that deviation from the manufacturers instructions when assembling enteral feeding systems can lead to bacterial contamination of these systems. The results also highlight the effect that system design, such as recessed pump set spikes and recessed nutrient container seals (both of which prevent care workers accidentally touching parts of the feeding system which may come into contact with the feed) have on reducing the number of bacteria gaining entry to the feed in the systems.

Effect of Acid Feeds on Feeding System Contamination

BACKGROUND AND OBJECTIVE

Bacterial contamination of the enteral nutrition delivery system (FS) has been well described. Case reports and prospective cohort studies suggest that bacterial contamination is a cause of morbidity and mortality in the critically ill patient. Because bacterial growth and replication is pH dependent, we hypothesized that acidified enteral feedings would lower incidence of bacterial contamination of the FS and potentially infectious morbidity and mortality of critically ill patients. Our objective was to evaluate the effect of acidified enteral feedings on bacterial growth in the FS and subsequent gastric and tracheal bacterial growth.

DESIGN

Randomized, double-blind, placebo-controlled, multicenter study.

SETTING

Eight mixed intensive care units at tertiary care hospitals.

PATIENTS

We recruited mechanically ventilated critically ill patients expected to remain ventilated ≥48 hours. We excluded patients with overt gastrointestinal bleeding, persistent acidemia, and renal failure requiring dialysis. We enrolled 120 patients: women, 38%; age, 57.6 ± 19.3 years, and mean APACHE II score, 21.6 ± 7.6.

INTERVENTIONS

Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group. Hydrochloric acid was added to achieve a pH to 3.5 in the experimental group.

MAIN OUTCOME MEASURES

Microbial growth in the FS, stomach, and trachea.

RESULTS

Compared with patients in the control group, patients who received acid feedings were less likely to have potentially pathogenic microorganisms in their FSs (19% versus 80% of patients [p ≤ .001] and 0.1 versus 0.8 organisms per specimen [p ≤ .001]). There were 151 organisms that were cultured in two or more sites. Of the 146 organisms cultured from the stomach, 22 (15%) were first cultured in the feeding system and 32 (22%) were cultured simultaneously in the feeding system and the stomach. Of the 58 organisms cultured in the trachea, 19 (33%) were first cultured in the feeding system and 6 (10%) were cultured simultaneously in the feeding system and the trachea.

CONCLUSIONS

The feeding system is a frequent source of gastric and tracheal contamination. Acidified enteral feedings reduces contamination of the feeding system and therefore may have an impact on subsequent colonization and infection. Larger studies of acidified enteral feedings are needed to examine their effect on infectious morbidity and mortality.

Clinical and laboratory evaluation of a closed enteral feeding system under cyclic feeding conditions: a microbial and cost evaluation

Cyclic feeding schedules are now commonly used in conjunction with closed enteral feeding systems. Some manufacturers and clinicians have speculated that closed system cyclic feeding may promote formula contamination via retrograde movement of bacteria during the "no-flow" periods. Using both laboratory and clinical settings, our study evaluated whether retrograde bacterial movement under "no-flow" conditions results in contamination of closed system feeding containers. The clinical phase was conducted with 57 closed system feeding containers used to feed nursing home residents. In both laboratory and clinical testing there was no evidence of container contamination at 36-48 h, nor was there evidence of retrograde movement of bacteria beyond the drip chamber. Formula waste and costs were also analyzed using several 24- or 36-h hang time scenarios. Provided the appropriate container size is used, potential cost savings between $67 to $135 per patient per month may be achieved with the 36-h hang time scenarios. Retrograde movement of bacteria does not appear to be a source of closed system feeding container contamination in systems that incorporate a drip chamber. Using the appropriate size feeding container and systems with at least a 36-h hang time will result in significant cost savings.

The effects of rinsing enteral delivery sets on formula contamination

This study investigated whether rinsing enteral delivery sets before formula addition affects formula contamination. Both a simulated and a clinical phase were conducted. In the simulated phase, Osmolite (Ross Laboratories, Columbus, OH) was infused continuously through 52 delivery sets into a flask via enteral infusion pumps for 24 hours. The delivery sets were randomly assigned to two groups of equal size. One group was rinsed with tap water before new formula was added at 8 and 16 hours, and the other group was not rinsed. At 8, 16, and 24 hours, samples of formula were collected from the delivery sets, and bacteria counts were obtained. In the clinical phase, 23 critically ill patients receiving Osmolite continuously were randomly assigned to a rinse or no-rinse group. The same formula addition and rinse protocol from phase I was used. Formula samples were obtained at 24 hours. In both phases, there were no significant differences between the rinse and no-rinse groups with respect to bacteria counts at any time period. The findings suggest that rinsing may be unnecessary if delivery sets are used continuously for 24 hours or less; however, the possibility of a type II error because of the small sample size of this study must be recognized.

Review: microbiology of the gastrostomy tube

This review summarizes what is presently known about microbial colonization of silicone gastrostomy feeding tubes and their deterioration. Feeding tubes are frequently colonized by fungal and bacterial organisms. Candida organisms seem to originate from the oral cavity from where they colonize the stomach and the gastrostomy tubes. It appears that many microorganisms are able to metabolize certain polymer additives, and although this is well described for polyvinyl chloride, it is not for silicone elastomers. However, clinical evidence for a role of microorganisms in the deterioration of silicone feeding tubes is very strong. The clinical significance of gastrointestinal tract seeding from gastrostomy tubes, which act as incubators, is not fully understood and deserves further study. Likewise, deterioration of feeding tubes must be investigated systematically to address the safety and economical issues it presents.

Contamination of a prefilled ready-to-use enteral feeding system compared with a refillable bag

The contamination of a refillable bag enteral feeding system was compared with a prefilled, ready-to-use system on four stable patients with gastrostomies in a longterm care facility. Samples were taken from the distal end of the tubing attached to the formula reservoir three times (just before administration to the patient, during the morning medication pass, and just before the reservoir change) during 24 hours for 3 days with use of the refillable bag, the ready-to-use system, and the ready-to-use system with a Y-port added. A Y-port was added to the ready-to-use system to facilitate administration of water, medications, residual checks, and specimen collection without disconnection of the gastrostomy tube from the formula reservoir tubing when it was apparent that the contamination levels of the refillable bag and the ready-to-use system were not different. Forty-one (65%) of the 63 specimens collected while the Y-port was not being used exceeded the acceptable contamination level for grade A pasteurized milk. Five (28%) of the 18 specimens collected while the Y-port was in use exceeded this level. Use of a Y-port is suggested when a prefilled ready-to-use system is used to decrease contamination as well as save nursing time.

Microbial contamination of enteral feeding tubes occurring during nutritional treatment

Enteral nutrition is an effective treatment for catabolic patients with normal intestinal absorption. However, tube-fed patients are at risk from superinfection. Our study is the first to evaluate in vivo the microbial contamination of solutions staying in the nasogastric tube of cancer patients receiving nutritional preparations. After daily feeding, the tube was rinsed with nonsterile tap water. Tap water staying overnight in the tube was considered as tube-rinsing solution. Microbial burden of nutritional preparations was determined on the fifth day of enteral nutrition, from opening the first container and throughout feeding. The next day, a sample of the tube-rinsing solution was cultured. All bacterial species were identified and antibiotic susceptibility pattern was assessed. Thirty-one cancer patients were included, 12 on the hospital's preparations and 19 on commercial feeding. Seven of the hospital--and none of the commercial--preparations were contaminated. Among the 48 samples collected during feeding, 16 were contaminated, including 10 hospital and 6 commercial preparations. All the 31 tube-rinsing solutions were contaminated and 102 strains cultured. Their median concentration was 10(6) colony-forming units/mL (range 10-10(10)). The strains were 48 Enterobacteriaceae, 20 group D streptococci, 9 Candida albicans, 9 Pseudomonas aeruginosa, and 16 others. Multiple antibiotic resistance was present in 12 of the 102 strains. Lower resistance was present in 33. The predominant microorganism of the tube-rinsing solution caused a bacterial colonization for three febrile patients. In conclusion, the feeding tube is an important reservoir for multiple antibiotic-resistant bacteria.

Retrograde (ascending) bacterial contamination of enteral diet administration systems

A prospective clinical study in three phases was performed to determine whether it was possible that enteral diet containers could become contaminated as a result of endogenous organisms ascending retrogradely from the enteral feeding tube via the giving set, and if this did occur whether the incidence could be altered by modifying enteral delivery systems. Each phase observed patients on enteral feeding over a 48-hour study period (phase I, n = 18; phase II, n = 17; phase III, n = 18). Each patient was prescribed an enteral diet of 2 L/24 h administered by continuous pump infusion from a closed 1-L sterile diet container. Four containers were used for each patient, and one giving set was used in the 48-hour period. Diet samples were taken at 12-hour intervals: two from the giving set before and after flushing with residual diet, and one from the diet container. Phases differed only in the design of the giving set: phase I had no drip chamber, phase II had a drip chamber, phase III had a drip chamber and an anti-reflux ball valve at the distal end. Both phase I and III had greater numbers of giving set samples colonized at 24, 36, and 48 hours. In phase I, 3 of 14 sterile diet containers were colonized with greater than 10(4) colony-forming organisms/mL of diet at 48 hours. Only phase II had no organisms contaminating the containers at 48 hours. We conclude that the retrograde spread of organisms from patient to sterile diet container does occur in clinical practice, and that a drip chamber in the giving set may prevent the problem.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial contamination of enteral feeds as a possible risk of nosocomial infection

The degree of microbiological contamination in enteral diets was studied and the possible infectious complications that could arise in the patient after administration of an enteral feed were evaluated. Of the 208 diets studied, 56 (26.9%) were contaminated and 152 (73.1%) were sterile. Of the 56 contaminated diets, 11 could be used as delivered, but the other 45 required further modification. Of the patients who had received enteral feeding, 43 developed gastrointestinal symptoms in the first 24 h (fever, vomiting, abdominal pain and diarrhoea). Twenty-nine (67.4%) had received a contaminated diet and 14 (32.6%) an uncontaminated one. We conclude that contamination of enteral feeds may constitute a risk factor for nosocomial infection, and consider it necessary to carry out epidemiological surveillance in order to control the factors which may lead to contamination of enteral diets.

Limiting bacterial contamination of enteral nutrient solutions: 6-year history with reduction of contamination at two institutions

Running enteral nutrient solution (ENS) bacterial contamination logs that were collected over a 6-year time frame are presented. At hospital A, reconstituted ENS were prepared by the pharmacy department in bulk and were frozen in the final container. These solutions were cultured and counted after 12 hours of storage at room temperature to stimulate this institution's hang time. Major reductions in ENS bacterial counts occurred after improvements in sanitation, a reduction in solution hang time, the conversion to the use of sterile water for dilution and reconstitution of ENS, and most dramatically, after the incorporation of a preservative (potassium sorbate) to reconstituted ENS. At hospital B, ENS usage consisted of canned feedings that were prepared by nursing personnel and were transferred to the feeding container at the bedside. Reductions in final counts of contamination of ENS occurred after procedural changes, which included container changes every 24 hours, use of sterile water for dilution, cleansing of can lids with alcohol swabs before use, rinsing and air drying of intermittent feeding containers between feedings, and limiting feeding container fills to 4-hour hang time quantities. At both institutions, the value of an ongoing three-class enteral quality control program with a defined acceptance/rejection criteria was demonstrated in that ENS contamination was reduced to acceptable levels comparable with federal standards for milk and dairy products.

The relationship between enteral formula contamination and length of enteral delivery set usage

Twenty-one delivery sets were collected from 21 patients who had received continuous Osmolite feedings over 24 hours. Delivery sets were than taken to the laboratory and hung for an additional 48 hours. In the laboratory, the delivery sets were rinsed with tap water and Osmolite was added every 12 hours. Formula samples were obtained from the delivery sets after they had been used for 24 hours, and every 12 hours during the additional 48 hours in the laboratory. Formula contamination was assessed by determining bacterial counts. Unacceptable contamination was defined as bacterial counts greater than or equal to 10(5) cfu/mL. The mean bacterial count was 2.8 x 10(5) cfu/mL at 24 hours, and all subsequent mean counts increased over time. There were statistically significant differences among the mean log bacterial counts at all time periods (p less than or equal to 0.0005) except between 36 hours and 48 hours (p = 0.019). Of the 21 delivery sets, 23.8% were unacceptably contaminated at 24 hours, and by 48 hours, 42.9% were unacceptable. These findings suggest that if 10(5) cfu/mL is used as a criterion, delivery sets should not be used for more than 24 hours in a hospital, and 24-hour use of delivery sets may even be too long.

Re-use of enteral feeding tubes--a potential hazard to the patient? A study of the efficiency of a representative range of cleaning and disinfection procedures

Some hospitals and manufacturers are now recommending that patients (particularly those on home enteral feeding) remove and re-insert their tubes on a daily basis. This study was carried out to evaluate the effectiveness of a representative range of currently used cleaning procedures in removing bacteria from the lumina of these tubes. One thousand-ml portions of feed experimentally contaminated with 10(2)-10(3) Klebsiella aerogenes ml(-1) were perfused through three types of commonly used polyurethane enteral feeding tubes for 15 h. The tubes were then cleaned by a range of methods including rinsing them with sterile water, sterile water and detergent and/or disinfection with hypochlorite solution. A further 1000-ml sterile feed was then perfused through the tubes for 15 h and it was found that residual organisms in the tubes multiplied to yield levels of 10(6)-10(9) colony-forming units (cfu) ml(-1) in the feed collected from the distal ends of the tubes after 15 h. It is concluded that none of the cleaning methods tested can be recommended as being totally effective in removing bacteria from the lumina of contaminated tubes.

The effect of handling procedures on microbial contamination of enteral feeds--a comparison of the use of sterile vs non-sterile gloves

The use of non-sterile disposable gloves to reduce the level of microbial contamination introduced into enteral feeds during the assembly of the feeding systems was investigated. No contamination was detected in any of the feed samples collected from the systems assembled wearing non-sterile gloves. The number of microorganisms transferred to the surface of agar plates used for fingerprint cultures was reduced from an average of 43-54 colony forming units (cfu) per plate for volunteers with bare hands to less than 1 cfu when they wore non-sterile gloves. No contamination was detected on plates touched by volunteers wearing sterile gloves.

Enteral feeding and infection in the immunocompromised patient

Evidence is accumulating that immunocompromised individuals are at an increased risk of infection from foodborne pathogens including Campylobacter jejuni, Listeria monocytogenes, Salmonella spp. Normal bacterial flora and contaminants of foods and enteral feeds can also result in nosocomial infection in susceptible individuals. Safe food handling, low-microbial diets, and measures to reduce bacterial contamination of enteral foods can reduce exposure to potential pathogens in the food supply.

Bacterial contamination and growth in two defined formula diets of different pH

We inoculated partially hydrolysed protein feed of low pH and an intact protein feed of neutral pH with various pathogenic bacteria, and showed that the low pH feed restricted bacterial growth. To study this effect in a clinical setting, 20 malnourished in-patients were randomised prospectively to receive one or other of these feeds. Both formulae were given as a continuous feed via a nasogastric tube, 1,000 ml over 12 h twice daily, using routine hygienic measures. On two occasions significant contamination was demonstrated (Erwinia herbicola and Acinetobacter Iwoffi), both occurring in the intact protein diet. When the bacteria were isolated and transferred to the hydrolysed protein diet, their growth was inhibited. The contamination did not cause clinical complications. The study demonstrates inhibition of microbial growth in a partially hydrolysed protein formula of low pH. This effect may reduce the risk of contamination, and limit infectious complications.

Microorganisms and diarrhea in enterally fed intensive care unit patients

Thirty-six intensive care unit patients, receiving aseptic or manually (routine) reconstituted enteral feeding formulas, were evaluated prospectively for the relationship of microbial involvement, gastric pH, and antimicrobial therapy to diarrhea. The routine protocol group had a significantly higher incidence of bacterial contamination than the aseptic protocol group (Fisher's exact test, p less than 0.05). There were no significant direct associations between isolate category (Gram-negative bacilli, Gram-positive cocci, Gram-negative cocci, yeast), gastric pH, or antimicrobials and diarrhea. However, two organisms (Group D Enterococci and yeast) were indirectly implicated in some cases of diarrhea.