Control of Infections Associated With Hemodialysis



Control of Infections Associated With Hemodialysis


Priti R. Patel

Nicola D. Thompson

Matthew J. Arduino


The findings and conclusions in this chapter are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.



In 2007, there were approximately 340,000 maintenance hemodialysis patients receiving care at some 5,240 outpatient hemodialysis facilities (1). This represents about 92% of the end-stage renal disease (ESRD) population receiving renal replacement therapy (hemodialysis, peritoneal dialysis, or renal transplantation) in the United States. Approximately 2,999 (1%) hemodialysis patients perform self or assisted therapy in their homes. The ESRD program is administered by the Centers for Medicare and Medicaid Services (CMS) of the Department of Health and Human Services and is the only Medicare entitlement that is based on the diagnosis of a medical condition.

Maintenance hemodialysis patients are at increased risk for infection because uremia is known to make patients with ESRD more susceptible to infectious agents through defects in cellular immunity, neutrophil function, and complement activation (2,3). In addition, since the process requires vascular access for extended periods and an extracorporeal circuit in an environment where multiple patients receive hemodialysis concurrently, repeated opportunities exist for transmission of infectious agents. Transmission of infectious agents, directly or indirectly through contaminated devices, equipment, supplies, dialysis fluids, injectable medications, environmental surfaces, or hands of healthcare personnel have all been demonstrated. Furthermore, hemodialysis patients require frequent hospitalizations and surgery, which increases their opportunities for exposure to healthcare-associated infections. This chapter describes (a) the major infectious diseases that can be acquired in the maintenance dialysis center setting, (b) important epidemiologic and environmental microbiologic considerations, and (c) infection control strategies.


MICROBIAL CONTAMINANTS IN HEMODIALYSIS SYSTEMS

Hemodialysis systems are complex and have components that contain a variety of fluid pathways that transport water, dialysate, dialysate effluent, and blood. These systems can become colonized or contaminated with a variety of microorganisms. There are many situations where certain types of water bacteria (gram negatives, environmental mycobacteria, and other gram positives) and fungi can persist and actively multiply in aqueous environments associated with hemodialysis equipment. This can result in the production of massive concentrations of microorganisms, primarily gram-negative bacteria, which can directly or indirectly affect patients by septicemia or endotoxemia (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 17).

Gram-negative water bacteria are commonly found in water supplies used for hemodialysis. These bacteria, in conjunction with fungi, can adhere to surfaces and form biofilms (glycocalyces), which are virtually impossible to eradicate (6,18, 19, 20, 21, 22, 23 and 24). Control strategies are designed not to eradicate bacteria but to prevent establishment of biofilms (25), reduce bacterial concentration to relatively low levels, and prevent their regrowth.

Although certain genera of gram-negative water bacteria (e.g., Burkholderia, Delftia, Enterobacter, Flavobacterium, Hydrogenophaga, Methylobacterium, Pseudomonas, Ralstonia, Serratia, Sphingomonas, and Stenotrophomonas) are most commonly encountered, virtually any bacterium that can grow in water can be a problem in a hemodialysis unit. Several species of environmental mycobacteria may also contaminate water treatment systems, including Mycobacterium chelonae, M. abscessus, M. fortuitum, M. gordonae, M. mucogenicum, M. scrofulaceum, M. kansasii, M. avium, and M. intracellulare; these microorganisms do not contain bacterial endotoxin but are comparatively resistant to chemical germicides (26, 27, 28, 29, 30 and 31). Some investigators have also reported isolating fungi from water used to prepare dialysate (18,19,32,33).

Gram-negative water bacteria can multiply even in water containing relatively small amounts of organic matter, such as water treated by distillation, softening, deionization, or reverse osmosis, reaching levels of 105 to 107 microorganisms/mL (6); these levels are not associated with visible turbidity. When treated water is mixed with dialysis concentrate, the resulting dialysis fluid is a balanced salt solution and growth medium almost as rich in nutrients as conventional nutrient broth (6,34). Gram-negative water bacteria growing in dialysis fluids can reach levels of 108 to 109 microorganisms/mL, without producing visible turbidity.

Bacterial growth in water used for hemodialysis depends on the types of water treatment system used, dialysate distribution systems, dialysis machine type, and
method of disinfection (Table 63-1) (6,20,26,35,36). Each component is discussed separately below.








TABLE 63-1 Factors Influencing Microbial Contamination in Hemodialysis Systems


























































































Factors

Comments


Water Supply (Water Source)

Ground water

Contains endotoxin and bacteria

Surface water

Contains high levels of endotoxin, bacteria, and other microorganisms


Water treatment at the dialysis center

None

Not recommended

Filtration

Prefilter

Particular filter to protect equipment; does not remove microorganisms

Absolute filter (depth or membrane)

Removes bacteria but unless changed frequently or disinfected, bacteria will accumulate and grow through the filter; acts as a significant reservoir of bacteria and endotoxin

Granular activated carbon (GAC)

Removes organics and available chlorine or chloramine; significant reservoir of water bacteria and endotoxin


Water treatment devices

Ion exchange (softener, deionization)

Softeners and deionizers remove cations and anions, contaminants from source water; significant reservoir for bacteria and endotoxin

Reverse osmosis

Removes bacteria, endotoxin, chemicals, and must be cleaned and disinfected; most systems employed for dialysis applications operate under high pressure

Ultraviolet germicidal irradiator

Kills most bacteria, but there is no residual, some UV-resistant bacteria can develop

Ultrafilter

Removes bacteria and endotoxin; operates on normal line pressure; can be positioned distal to storage tank and deionizer; must be disinfected or changed


Water and dialysate distribution system

Distribution pipes

Size

Oversized diameters and length decrease fluid flow and increases bacterial reservoir in the form of biofilms for both treated water and central delivery systems (bicarbonate concentrate or bicarbonate dialysate)

Materials

Pipe materials influence bacterial colonization and biofilm formation, as well as what types of chemical disinfectants can be used

Construction

Rough joints, dead ends, and unused branches can act as bacterial reservoirs

Elevation

Outlet taps should be located at highest elevation to prevent loss of disinfectant

Storage tanks

Generally undesirable because of large surface area and can act as a reservoir for water bacteria; a properly designed tank can minimize this risk


Dialysis machines

Single pass

Disinfectant should have contact time with all parts of the machine that are in contact with treated water or dialysate

Recirculating single pass, or recirculating batch

Recirculating pumps and machine design allow for massive contamination levels if not properly disinfected. Overnight disinfection has been recommended



Microbial Contamination of Water

Water used for the production of dialysis fluid must be treated to remove chemical and microbial contaminants. The Association for the Advancement of Medical Instrumentation (AAMI) has published guidelines and recommended practices for the chemical and microbial quality of water used to prepare dialysis fluid and reprocess hemodialyzers (Table 63-2) (37,38,39). Some components of the water treatment system may allow for amplification of water bacteria (Table 63-1). For example, ion exchangers such as water softeners and deionizers do not remove endotoxin or microorganisms, and provide many sites for significant bacterial multiplication (40, 41 and 42). Granular activated carbon adsorption media (i.e., carbon filters) are used primarily to remove certain organic compounds and available chlorine (free and combined) from water (43, 44 and 45), but they also significantly increase the level of water bacteria, yeast, fungi, and endotoxins (46, 47 and 48).

A variety of filters are marketed to control bacterial contamination of water and dialysis fluids. Most are inadequate, especially if they are not either routinely disinfected or frequently changed. Particulate filters, commonly called prefilters, operate by depth filtration, which allows
larger particles to be trapped near the surface of the filter while smaller particles penetrate the larger open areas to be trapped nearer the center of the filter in the smaller openings. Depth filters remove larger particulates from the water but do not remove bacteria or endotoxin; these filters can become colonized with gram-negative water bacteria, resulting in higher levels of bacteria and endotoxin in the filter effluent than in the feed water. Absolute filters, including membrane types, remove 100% of particles above the stated pore sizes (≥1 µm) and temporarily remove bacteria from passing water; however, some of these filters tend to clog, and gram-negative water bacteria can “grow through” the filter matrix and colonize downstream surfaces within a few days. Further, absolute filters do not reduce levels of endotoxin in the effluent water. All of these filters should be changed regularly in accordance with the manufacturer’s directions and disinfected in the same manner and at the same time as the rest of the water distribution system.








TABLE 63-2 AAMI Microbial Quality Standards for Dialysis Fluids

Microbial Bioburden

Endotoxin


Type of Fluid

Maximum Contaminant Level

Action Level

Maximum Contaminant Level

Action Level


Water for all purposes

200 CFU/mL

50 CFU/mL

2 EU/mL

1 EU/mL


Conventional dialysate

200 CFU/mL

50 CFU/mL

2 EU/mL

1 EU/mL


Ultrapure dialysate

1 CFU/10 mL


0.03 EU/mL


Dialysate for infusion

1CFU/1,000 La


0.03 EU/mL


a Compliance with a maximum bacterial level of 10-6 CFU/mL cannot be demonstrated by culturing, but by processes developed by the machine manufacturers.


Ultraviolet germicidal irradiation (UVGI) is sometimes used to reduce microbial contamination in water, but the use of UVGI has some special considerations. The lamp should be appropriately sized for the flow rate of water passing through the device, and the energy output should be monitored to insure effectiveness of the lamp. Manufacturers of the lamp may require a routine replacement schedule. Some bacterial populations may develop resistance to UVGI (49). In recirculating dialysis distribution systems, repeated exposure to UVGI is used to ensure adequate disinfection; however, this approach allows for selection of UVGI-resistant microorganisms. In addition, bacterial endotoxins are not affected.

Reverse osmosis is an effective water treatment modality that is used in more than 97% of US hemodialysis centers, either alone or in combination with deionization (50). Reverse osmosis possesses the singular advantage of being able to remove a variety of substances including microorganisms and endotoxin from supply water based primarily on particle size and adsorption to the membrane. However, low numbers of microorganisms may penetrate the membrane or by other means (leaks around seals) colonize downstream portions of the water distribution system. Consequently, the reverse osmosis unit must be disinfected routinely.

A water treatment system that produces chemically adequate water while avoiding high levels of microbial contamination is highly recommended. The components in a typical water system should include (a) prefilters, (b) a water softener, (c) carbon adsorption tanks (at least two in series), (d) a particulate filter or absolute filter (to protect the reverse osmosis membrane), and (e) a reverse osmosis unit. If one includes a deionization unit as a polisher (postreverse osmosis unit) or a storage tank, the final component in the system should be an ultrafilter to remove both microorganisms and endotoxin (51,52). As the incoming tap water passes through the system components, it becomes more chemically pure, but the level of microbial contamination increases, which is why the use of reverse osmosis and ultrafiltration is important. Additional components or processes may be included in the pretreatment chain (Table 63-1) depending on the pH, potable water disinfectant, and the chemical quality of the incoming municipal water (52). If the system is adequately disinfected and properly maintained, the microbial content of water should be well within the recommended limits.


Distribution Systems

Water that has passed through the water distribution system (product water) is then distributed to individual dialysis machines, where it is combined with dialysate concentrates (bicarbonate and acid concentrates), and to a reprocessing area if a facility reprocesses hemodialyzers for reuse. It may also be combined with concentrates at a central location where the resulting dialysis fluid is supplied to the individual machines. Plastic pipe (most often schedule 80 polyvinyl chloride) is then used to distribute water or dialysis fluids to the dialysis machines. Distribution systems should include the use of a loop-based system and no dead end pipes (dead legs). Outlets to dialysis machines should have a relatively short path with the least amount of fittings and the use of valves with minimal dead space. Voids, dead ends, and large surface areas serve as sites for microbial colonization. Large-diameter pipes decrease fluid velocity and increase the wetted surface area available for microbial colonization (34,53), and long pipe runs increase the available surface area for colonization; therefore, both of these situations should be avoided if possible. Gram-negative water bacteria in fluids remaining in pipes overnight can rapidly multiply and colonize wetted surfaces of the distribution system, producing microbial populations and endotoxin in quantities proportional to the total volume of the surface area. Such colonization results in the formation of protective biofilm, which is difficult to remove and protects the bacteria and other microorganisms from disinfection (54).


Routine disinfection of the water or dialysate distribution system should be performed on a regular basis so that the microbial quality of the fluids is within the acceptable standards range. The minimum frequency of disinfection may be at least monthly (34,51). However, AAMI standards and recommended practices are community consensus standards, and do not specify a schedule for disinfection other than to suggest that routine disinfection be conducted. In many instances, microbiologic monitoring can be used to determine the frequency of testing and disinfection of the distribution system (51,52).

To prevent disinfectant from draining from pipes by gravity before adequate contact time, distribution systems should be designed with all taps at equal elevation and at the highest point of the system. Furthermore, the system should be free of rough joints, dead ends, oversized pipes, and long pipe runs. Fluid trapped in such stagnant areas can serve as reservoirs for bacteria and fungi that later contaminate the rest of the distribution system (55).

Storage tanks greatly increase the volume of fluid and surface area of the distribution system. If used, these should be designed with a conical-shaped bottom so that water exits the storage tank at its lowest point (and allows the tank to be drained), fitted with a tight sealing lid, and equipped with a spray head, and possesses an air vent containing a bacteriologic filter. Storage tanks should also be routinely cleaned, disinfected, and drained. In order to remove biofilm, use of strong oxidizers may aid in stripping biofilm from surfaces; however, physical scrubbing of the inner surfaces of the tank may be necessary. When using a storage tank, an ultrafilter should be incorporated before water is pumped into the distribution system (51,52).


Hemodialysis Machines

In the 1970s, most dialysis machines were of the recirculating or recirculating single-pass type; their design contributed to relatively high levels of gram-negative bacterial contamination in dialysis fluid. Currently, virtually all dialysis machines in the United States are single-pass machines. Single-pass machines tend to respond to adequate cleaning and disinfection procedures and, in general, have lower levels of bacterial contamination than do recirculating machines. Levels of contamination in single-pass machines depend primarily on the microbiologic quality of the incoming water and the method of machine disinfection (6,51).

Disinfection of Hemodialysis Systems Routine disinfection of isolated components of the dialysis system frequently produces inadequate results. Consequently, the total dialysis system (water treatment system, distribution system, and dialysis machine) should be included in the disinfection procedure.

Disinfection of dialysis systems usually employs sodium hypochlorite solutions, hydrogen peroxide solutions, commercially available peracetic or peroxyacetic acid (PAA) disinfectants, ozone, and in some systems hot-water pasteurization. Sodium hypochlorite solutions are convenient and effective in most parts of the dialysis system when used at the manufacturer’s recommended concentrations. Also, the test for residual available chlorine to confirm adequate rinsing is simple and sensitive. However, because chlorine is corrosive, it is usually rinsed from the system after a relatively short dwell time of 20 to 30 minutes. The rinse water invariably contains microorganisms that can multiply to significant levels if the system is permitted to stand overnight (34). Therefore, disinfection with chlorine-based disinfectants is best performed before the start of the first patient treatment session rather than at the end of the day. In centers dialyzing patients in multiple shifts with either batch or recirculating hemodialysis machines, it may be reasonable to disinfect with chlorine-based disinfectants between shifts and with another disinfectant or process (e.g., PAA) at the end of the day. Single-pass machines may be disinfected at the end or beginning of the treatment day.

Aqueous formaldehyde, PAA, hydrogen peroxide, or glutaraldehyde solutions can produce good disinfection results (20,56,57). These products are not as corrosive as hypochlorite solutions and can be allowed to dwell in the system for long periods of time when the system is not in operation. However, formaldehyde, which has good penetrating power, is considered an environmental hazard and potential carcinogen and has irritating qualities that may be objectionable to staff (58). The U.S. Environmental Protection Agency (EPA) has also limited the amount of formaldehyde that can be discharged into the wastewater stream, which has drastically reduced the use of this chemical in the dialysis community as a disinfectant. PAA and hypochlorite-based products are commercially available and are designed for use with dialysis machines when used according to the manufacturers’ labeled instructions. Glutaraldehyde use is limited because it is considered to be a sensitizer and may pose a risk to healthcare workers; it is more frequently used for dialyzer reprocessing and only in a minority (<4%) of facilities in the United States (59).

Some dialysis systems (both water treatment and distribution systems, some hemodialysis machines) use hotwater disinfection (pasteurization) for control of microbial contamination. In this type of system, water heated to >80°C (176°F) is passed either through the water distribution system and the fluid pathway of the hemodialysis machine, or just through the hemodialysis machine at the end of the day. These hot-water systems are excellent for controlling microbial contamination.


Monitoring of Water and Dialysis fluid

Microbiologic and endotoxin standards for water and dialysis fluids were originally based on the results of culture assays performed during epidemiologic investigations (34,35,52,53,60). However, as knowledge improved about the long-term effect of dialysis fluids on patient inflammatory responses, the recommended microbial standards have been revised (Table 63-2) (37,38,39). There is increasing evidence that the microbial quality of hemodialysis fluids plays a role in the chronic inflammatory response syndrome impacting anemia management, serum albumin level, and rate of loss of residual renal function in dialysis patients (61,62, 63, 64, 65 and 66,67,68,69,70, 71, 72, 73, 74 and 75). Increasing data suggest that use of ultrapure water and dialysate would benefit maintenance dialysis patients. However, there have been no randomized controlled studies to evaluate and confirm the impact on health outcomes.

Water samples should be collected from a source as close as possible to where water enters the dialysate proportioning unit. In most cases, this is the tap (not from the hose
connecting the tap to the dialysis machine) at the dialysis station, but may also be a sampling port on the hemodialysis machine. Water samples should be collected at least monthly (more frequent monitoring may be necessary) from several locations within the dialysis unit. Samples should also be collected after any modifications or maintenance has been made to the water treatment system or water distribution system. Dialysate samples should be collected during or at the end of the dialysis treatment from a source close to where the dialysis fluid either enters or leaves the dialyzer. Dialysate samples should be collected at least monthly from a representative number of dialysis machines. Samples of water and dialysate should also be collected whenever pyrogenic reactions are suspected (53). If centers reprocess hemodialyzers for reuse on the same patient, water used to prepare disinfectant and rinse dialyzers should also be assayed monthly. The maximum contaminant levels are 200 CFU/mL and 2 EU/mL (Table 63-2) (37,38,39).

Specimens should be assayed within 30 minutes of collection or refrigerated at 4°C and assayed within 24 hours of collection. Conventional laboratory methods, such as the spread plate or membrane filter technique, can be used. Calibrated loops should not be used because they sample only a small volume, are inaccurate, and often do not have the sensitivity to detect the current action or maximum contamination limits. Blood and chocolate agar media should not be used because the microorganisms have adapted to nutrient-poor environments and thus require specific media designed for the recovery of microorganisms from water. In addition, microorganisms that are found in bicarbonate dialysis fluids require a small amount of sodium chloride. Consequently, to cover both conditions needed, trypticase soy agar (soybean casein digest agar) is currently recommended; however, standard methods agar, plate count agar, or tryptose glucose yeast extract agar may also be used (39,76,77). The assay should be quantitative, not qualitative, and a standard technique for enumeration should be used. Colonies should be counted after 48 hours of incubation at 36°C (39,51, 52 and 53,78,79). Total viable counts are the objective of plate counts. Endotoxin testing should be conducted using either the Limulus amebocyte lysate assay, Gel-clot method, or one of the kinetic methods.

In an outbreak investigation, the assay methods may need to be both qualitative and quantitative; detection of nontuberculous mycobacteria and, in some cases, fungi in water or dialysate may be desirable. In such instances, plates should be incubated for 5 to 14 days at both 36°C and 28°C to 30°C.


DIALYSIS-ASSOCIATED PYROGENIC REACTIONS

Gram-negative bacterial contamination of dialysis water or components of the dialysis system (water, dialysate, water used for reprocessing) can cause pyrogenic reactions. Pyrogenic reactions are defined as objective chills (visible rigors), fever (oral temperature ≥37.8°C [100°F]), or both in a patient who was afebrile (oral temperature up to 37°C [98.6°F]) and had no signs or symptoms of an infection before the start of the dialysis treatment session (11,80,81). Depending on the type of dialysis system and the level of contamination, fever and chills may start 1 to 5 hours after dialysis has been initiated. Other symptoms may include hypotension, headache, myalgia, nausea, and vomiting. Pyrogenic reactions can occur without bacteremia; because presenting signs and symptoms cannot differentiate bacteremia from pyrogenic reactions, blood cultures are necessary.

During 1990 to 2002, an annual average of 20% to 24% of the hemodialysis centers in the United States reported at least one pyrogenic reaction in the absence of septicemia in patients undergoing maintenance dialysis (50,59,82, 83, 84, 85, 86, 87, 88, 89 and 90). Pyrogenic reactions can result from passage of bacterial endotoxin (lipopolysaccharide [LPS]) or other substances in the dialysate across the dialyzer membrane (91, 92, 93 and 94,95) or from the transmembrane stimulation of cytokine production in the patient’s blood by endotoxin in the dialysate (92,96, 97 and 98). In other instances, endotoxin can enter directly into the bloodstream with fluids that are contaminated with gram-negative bacteria (99). The signs and symptoms of pyrogenic reactions without bacteremia generally abate within a few hours after the dialysis has been stopped. If gram-negative sepsis is associated, fever and chills may persist, and hypotension is more refractory to therapy (4,99).

When a pyrogenic reaction occurs, the following steps are usually recommended: (a) careful physical examination of the patient to rule out other causes of chills and fever (e.g., pneumonia, vascular access infection, urinary tract infection); (b) blood cultures, and other diagnostic tests (e.g., chest radiograph), and other cultures as clinically indicated; (c) collection of dialysate from the dialyzer (downstream side) for quantitative and qualitative microbiological culture; and (d) recording of the incident in a log or other permanent record. Determining the cause of these episodes is important, because they may be the first indication of a remediable problem.

The higher the level of bacteria or endotoxin in dialysis fluid, the higher is the probability that the bacteria or their products will pass through the dialyzer membrane, thus producing bacteremia or a pyrogenic reaction by stimulating cytokine production in a patient. In an outbreak of febrile reactions among patients undergoing hemodialysis, attack rates were directly proportional to the level of microbial contamination in the dialysis fluid (6). Prospective studies also demonstrated a lower pyrogenic reaction rate among patients when they underwent dialysis with dialysis fluid from which most bacteria had been removed, compared to patients who underwent dialysis with fluid that was highly contaminated (mean 19,000 CFU/mL) (5,80,100).

Among nine outbreaks of bacteremia, fungemia, and pyrogenic reactions not related to dialyzer reuse investigated by the Centers for Disease Control and Prevention (CDC), inadequate disinfection of the water distribution system or dialysis machines was implicated in seven (Table 63-3) (4,9,55,101, 102, 103, 104 and 105). The most recent outbreaks occurred at dialysis centers using dialysis machines that had a port (waste-handling option or WHO port) that allowed disposal of the extracorporeal circuit priming fluids. One-way check valves in the WHO had not been maintained, checked for competency, or disinfected as recommended, thus allowing backflow from the effluent dialysate path into and contamination of the port and the attached blood line (103,104,105).












TABLE 63-3 Outbreaks of Dialysis-Associated Illnesses Investigated by the Centers for Disease Control and Prevention, 1975-2008





































































































































































































































Description

Cause(s) of Outbreak

Corrective Measure(s) Recommended

Reference


Bacteremia, Fungemia, or Pyrogenic Reactions not Related to Dialyzer Reuse


Pyrogenic reactions in 49 patients

Untreated city water contained high levels of endotoxin

Install a reverse osmosis system

(4)


Pyrogenic reactions in 45 patients

Inadequate disinfection of the fluid distribution system

Increase disinfection frequency and contact time of the disinfectant

(55)


Pyrogenic reactions in 14 patients; 2 bacteremia; 1 death

Reverse osmosis water storage tank contaminated with bacteria

Remove or properly maintain and disinfect the storage tank

(35)


Pyrogenic reactions in six patients; seven bacteremias

Inadequate disinfection of water distribution system and dialysis machines; improper microbial assay procedure

Use correct microbial assay procedures; disinfect water treatment system and dialysis machines following manufacturer’s recommended procedures

(301)


Bacteremia in 35 patients with central venous catheters (CVCs)

CVCs used as facilities primary vascular access; median duration of infected catheters was 311 d; improper aseptic techniques

Uses CVCs when only absolutely necessary for vascular access; use appropriate aseptic technique when inserting and performing routine catheter care

(302)


Three pyrogenic reactions and 10 bacteremias in patients treated on machines with a port for disposal of dialyzer priming fluid (waste-handling option or WHO port)

Incompetent check valves allowing backflow of fluid from the waste side of the machine into attached blood tubing; bacterial contamination of the WHO

Routine disinfection and maintenance of the dialysis machine including the WHO; check competency of WHO prior to patient treatment

(103)


Bacteremia in 10 patients treated on machines with WHO port

Incompetent backflow to allow backflow from dialysate effluent side of the machine in the WHO port and attached bloodlines

Routine maintenance, disinfection, and check for valve competence of the WHO port

(104)


Outbreak of pyrogenic reactions and gramnegative bacteremia in 11 patients

Water distribution system and machines were not routinely disinfected according to manufacturer’s recommendations. Water and dialysate samples were cultured using a calibrated loop and blood agar plates—results were always as no growth

Disinfect machines according to manufacturer’s recommendations and include reverse osmosis water distribution system in the weekly disinfection schedule; microbiological assay should be performed via membrane filtration or spread plate using Trypticase Soy agar

(9)


Phialemonium curvatum access infections in four dialysis patients; two of these patients died of systemic disease

Observations at the facility noted some irregularities in site prep for needle insertion. All affected patients had synthetic grafts. One environmental sample was positive for P. curvatum (condensate pan of HVAC serving the unit)

Review infection control practices and clean and disinfect HVAC system where water accumulated. Perform surveillance on all patients

(303)


Phialemonium curvatum blood stream infections in two patients

Water system and dialysis machines with WHO ports not routinely maintained; water system contained dead legs and lab used wrong assays

Conduct routine maintenance and disinfection of machines and WHO ports; redesign water system to eliminate dead legs; have a routine schedule for disinfection of the water system

(105)


Bacteremia/Pyrogenic Reactions Related to Dialyzer Reprocessing


Mycobacterial infections in 27 patients

Inadequate concentration of dialyzer disinfectant

Increase formaldehyde concentration used to disinfect dialyzers to 4%

(27)


Mycobacterial infections in five high-flux dialysis patients; two deaths

Inadequate concentration of dialyzer disinfectant and inadequate disinfection of water treatment system

Use higher concentration of peracetic acid for reprocessing dialyzers and follow manufacturers labeled recommendations; Increase frequency of disinfecting the water treatment system

(304)


Bacteremia in six patients

Inadequate concentration of dialyzer disinfectant; water used to reprocess dialyzers did not meet AAMI standards

Use AAMI quality water; insure proper germicide concentration in the dialyzer

CDC unpublished data


Bacteremia and pyrogenic reactions in six patients

Dialyzer disinfectant diluted to improper concentration

Use disinfectant at the manufacturers’ recommended dilution and verify concentration

(79)


Bacteremia and pyrogenic reactions in six patients

Inadequate mixing of dialyzer disinfectant

Thoroughly mix disinfectant and verify proper concentration

(10)


Bacteremia in 33 patients at two dialysis centers

Dialyzer disinfectant created holes in the dialyzer membrane

Change disinfectant (product was withdrawn from the market place by the manufacturer)

(305,306)


Bacteremia in six patients; all blood isolates had similar plasmid profiles

Dialyzers were contaminated during removal and cleaning of headers with gauze; staff not routinely changing gloves; dialyzers not reprocessed for several hours after disassembly and cleaning

Do not use gauze or similar material to remove clots from header; change gloves frequently; process dialyzers after rinsing and cleaning

(307)


Pyrogenic reactions in three high-flux dialysis patients

Dialyzer reprocessed with two disinfectants; water for reuse did not meet AAMI standards

Do not disinfect dialyzers with multiple germicides; more frequent disinfection of water treatment system and conduct routine environmental monitoring of water for reuse

(308)


Pyrogenic reactions in 14 high-flux dialysis patients; one death

Dialyzers rinsed with city (tap) water containing high levels of endotoxin; water used to reprocess dialyzers did not meet AAMI standards

Do not rinse or reprocess dialyzers with tap water; use AAMI quality water for rinsing and preparing dialyzer disinfectant

(309)


Pyrogenic reactions in 18 patients

Dialyzers rinsed with city (tap) water containing high levels of endotoxin; water used to reprocess dialyzers did not meet AAMI standards

Do not rinse or reprocess dialyzers with tap water; Use AAMI quality water for rinsing and preparing dialyzer disinfectant

(11)


Pyrogenic reactions in 22 patients

Water for reuse did not meet AAMI standards; improper microbiological technique was used on samples collected for monthly monitoring

Use the recommended assay procedure for analysis of water and dialysate; disinfect water distribution system

(8)


Bacteremia and candidemia among patients in seven dialysis units (MN and CA)

Dialyzers were not reprocessed in a timely manner; some dialyzers refrigerated for extended periods of time before reprocessing; Company recently made changes to header cleaning protocol

Reprocess dialyzers as soon as possible; follow joint CDC and dialyzer reprocessing equipment and disinfectant manufacturer guidance for cleaning and disinfecting headers of dialyzer

CDC unpublished data


Transmission of Viral Agents


26 patients seroconvert to HBsAg+ during a 10-mo period

Leakage of coil dialyzer membranes and use of recirculating bath dialysis machines

Separation of HBsAg+ patients and equipment from all other patients

(181)


19 patients and 1 staff member seroconvert to HBsAg+ during a 14-mo period

No specific cause determined; falsepositive HBsAg results caused some susceptible patients to be dialyzed with infected patients

Laboratory confirmation of HBsAg+ results; strict adherence to glove use and use of separate equipment for HBsAg+ patients

(310)


24 patients and 6 staff seroconverted to HBsAg+ during a 10-mo period

Staff not wearing gloves; surfaces not properly disinfected; improper handling of needles/sharps resulting in many staff needlestick injuries

Separation of HBsAg+ patients and equipment from susceptible patients; proper precautions by staff (e.g., gloves; handling of needles and sharps)

(181)


13 patients and 1 staff member seroconvert to HBsAg+ during a 1-mo period

Extrinsic contamination of intravenous medication being prepared adjacent to an area where blood samples were handled

Separate medication preparation area from area where blood processing for diagnostic tests is performed

(186)


Eight patients seroconverted to HBsAg+ during a 5-mo period

Extrinsic contamination of multidose medication vial shared by HBsAg+ and HBV-susceptible patients

No sharing of supplies, equipment, and medications between patients

(CDC, unpublished data)


Seven patients seroconverted to HBsAg+ during a 3-mo period

Same staff caring for HBsAg+ and HBV-susceptible patients

Separation of HBsAg+ patients from other patients; same staff should not care for HBsAg+ and HBV susceptible patients

(181)


Eight patients seroconverted to HBsAg+ during 1 mo

Not consistently using external pressure transducer protectors; same staff members cared for both HBsAg+ patients and HBV-susceptible patients

Use external pressure transducer protectors and replace after each use; same staff members should not care for HBV-infected and susceptible patients on the same shift

(300)


14 patients seroconvert to HBsAg+ during a 6-wk period

Failure to review results of admission and monthly HBsAg testing; inconsistent hand washing and use of gloves; adjacent clean and contaminated areas; <20% of patients vaccinated

Proper infection control precautions for dialysis facilities; routine review of serologic testing; hepatitis B vaccination of all patients

(184)


Seven patients on the same shift seroconvert to HBsAg+ during a 2-mo period

Same staff members cared for HBsAg+ and HBV-susceptible patients on the same shift; common medication and supply carts were moved between stations, and multidose vials were shared; no patients vaccinated

Dedicated staff for HBsAg+ patients; no sharing of equipment or supplies between any patients; centralized medication and supply areas; hepatitis B vaccination of all patients

(184)


Four patients seroconverted to HBsAg+ during a 3-mo period

Transmission appeared to occur during hospitalization at an acute-care facility; no patients vaccinated

Hepatitis B vaccination of all patients

(184)


11 patients seroconverted to HBsAg+ during a 3-mo period

Staff, equipment, and supplies were shared between HBsAg+ and HBV-susceptible patients; no patients were vaccinated

Dedicated staff for HBsAg+; no sharing of medication or supplies between any patients; hepatitis B vaccination of all patients

(184)


Two patients converted to HBsAg+ during a 4-mo period

Same staff cared for HBsAg+ and HBV-susceptible patients; no patients vaccinated

Hepatitis B vaccination of all patients; dedicate staff for the care of HBsAg+ patients; no sharing of supplies or medication between patients

(184)


Six patients converted to HBsAg+ during a 6-mo period

Transmission occur during hospitalization at an acute-care facility; same staff cared for HBsAg+ and HBV-susceptible patients; no patients vaccinated

Hepatitis B vaccination of all patients; review HBsAg status of chronic hemodialysis patients who require hospitalization; no sharing of equipment, supplies, or medication between patients

(187)


36 patients with liver enzyme elevations consistent with Non-A, Non-B hepatitis

Environmental contamination with blood

Utilize proper precautions (e.g., gloving of staff; environmental cleaning); monthly liver function tests (e.g., ALT)

(308)


35 patients with elevated liver enzymes consistent with Non-A, Non-B hepatitis during a 22-mo period; 82% of probable cases were anti-HCV+

Inconsistent use of infection control precautions, especially hand washing

Strict compliance to aseptic technique and dialysis center precautions

(311)


HCV infection developed in 7/40 (18%) HCV-susceptible patients; shift specific attack rates of 29-36%

Multidose vials left on top of machine and used for multiple patients; routine cleaning and disinfection of surfaces and equipment between patients not routinely done; arterial line for draining prime dripped into a bucket that was not routinely cleaned or disinfected between patients

Strict compliance with infection control precautions for all dialysis patients; routine HCV testing

(252,253)


HCV infection developed in 5/61 (8%) HCV-susceptible patients

Sharing of equipment and supplies between chronically infected and susceptible patients; gloves not routinely used; clean and contaminated areas not separated

Strict compliance with infection control precautions for all dialysis patients; CDC does not recommend separation of equipment/supplies between HCV-infected and susceptible patients

(252,253)


HCV infection developed in 3/23 (13%) HCV-susceptible patients; shift specific attack rate 27%

Supply carts moved between stations and contained both clean and blood-contaminated items; medications prepared in the same area used for disposal of used injection equipment

Strict compliance with infection control precautions for all dialysis patients

(252,253)


HCV infection developed in 7/52 (13%) HCV-susceptible patients; shift specific attack rates 4-21%

Medication cart moved between stations and contained both clean and blood-contaminated items; single-dose medication vials used for multiple patients; cleaning and disinfection of surfaces and equipment between patients not routinely done

Strict compliance with infection control precautions for all dialysis patients

(252,253)


HCV infection developed in 9/90 (10%) HCV-susceptible patients.

Cleaning and disinfection of surfaces and equipment between patients not routinely done; gloves not routinely used; medications not stored in separate clean area

Strict compliance with infection control precautions for all dialysis patients; routine HCV testing

(254)


HCV infection developed in 8/107 (7.5%) HCV-susceptible patients

Poor medication handling and infusion practices

Proper training of personnel on aseptic technique and compliance with infection control precautions for dialysis setting

(255)



Hemodialyzer Reuse

From 1976 to 1997, the percentage of maintenance dialysis centers in the United States that reported reuse of disposable hollow-fiber dialyzers increased steadily; the largest increase (126%) occurred during the period between 1976 and 1982, when percentage of facilities reprocessing dialyzers increased from 18% to 43%, and the percentage of facilities reprocessing peaked at 82% in 1997 (90). However, the percentage of facilities reporting reusing dialyzers had declined to 63% in 2002 (59). This decline was primarily driven by a large dialysis chain’s decision to discontinue the practice of reuse and to only use single-use dialyzers.

In 1986, AAMI Standards for reprocessing hemodialyzers (106) were adopted by the United States Public Health Service (USPHS) and were incorporated into regulation by the CMS. In general, dialyzer reuse appears to be safe if performed according to strict and established protocols (22). In the United States, dialyzer reuse has not been associated with the transmission of blood-borne pathogens such as hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) (107,108). However, the reprocessing of dialyzers has been associated with pyrogenic reactions (107). These adverse events may be the result of the use of incorrect concentrations of chemical germicides, failure to maintain appropriate water quality, or improper cleaning (e.g., header cleaning practices). Manual reprocessing of dialyzers that does not include a test for membrane integrity, such as a pressure-leak test, may fail to detect membrane defects and may be a cause of both pyrogenic reactions and bacteremia (107,108).


The procedures used to reprocess hemodialyzers generally constitute high-level disinfection rather than sterilization (22,109). There are several liquid chemical germicides that have been used for high-level disinfection of dialyzers. Formaldehyde is a chemical solution from chemical supply houses and is not specifically formulated for dialyzer disinfection. There are commercially available chemical germicides specifically formulated for this purpose (e.g., PAA, chlorine-, and glutaraldehyde-based products) that are approved by the U.S. Food and Drug Administration (FDA) as sterilants or high-level disinfectants for reprocessing hemodialyzers. During the period between 1983 and 2002, the percentage of centers using formaldehyde for reprocessing dialyzers decreased from 94% to 20%, while the percentage using PAA increased from 5% to 72%. Only a minority of facilities (4%) reported using either glutaraldehyde or heat disinfection (59).

In 1983, most centers used 2% aqueous formaldehyde with a contact time of approximately 36 hours to disinfect dialyzers (110). In 1982, a dialysis center using this regimen experienced an outbreak of infections caused by nontuberculous mycobacteria (27). It was subsequently shown that the 2% formaldehyde regimen was not effective against nontuberculous mycobacteria. Rather, a regimen of 4% formaldehyde with a minimum contact time of 24 hours was required to inactive high numbers of these microorganisms and was recommended as the minimum solution for reprocessing dialyzers (22,107,109). A similar outbreak of systemic mycobacterial infections in five hemodialysis patients, resulting in two deaths, occurred when high-flux dialyzers were contaminated with M. abscessus during manual reprocessing and disinfected with a commercial disinfectant prepared at a concentration that did not ensure complete inactivation of mycobacteria (28). These two outbreaks of infections in dialysis patients emphasize the need to use dialyzer disinfectants at concentrations that are effective against more chemically resistant microorganisms, such as mycobacteria.

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Jun 22, 2016 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Control of Infections Associated With Hemodialysis

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