1. Epidemiology and host defense are concerned with defining and explaining the interrelationship of the host, agent, and environment in the prevention and control of disease

2. The principles of infection prevention and control provide a foundation for the delivery of infusion therapy

3. Initiation of an intravenous catheter breaks the transcutaneous skin barrier, which is the first line of host defense, and provides an avenue of entry for many of the organisms capable of causing infection

1. Body mobilizes a complex system of cells and organs called the immune system to neutralize or fight invading pathogens

2. One missing element can cause the entire immune system to be ineffective

3. Leukocytes, or white blood cells, are important components of the immune system

a. Normal white blood cell count ranges from 4,500 to 10,000 per cubic millimeter, with neutrophils and lymphocytes comprising 80% to 90% of the total white blood cell count

b. There are three types of leukocytes: granulocytes, monocytes, and lymphocytes

c. Differential white blood cell count provides more specific information related to infection and disease processes

4. Granulocytes and monocytes are the foundation of the nonspecific immune response

a. Granulocytes—divided into three groups: neutrophils, eosinophils, and basophils

1) Neutrophils or polymorphonuclear leukocytes (bands and segments)

a) Body’s first line of defense and are the first cells to appear in large numbers at the site of infection

b) Segments are mature neutrophils; bands are less mature neutrophils

c) Bands and segments are commonly referred to as polymorphonuclear leukocytes and are capable of destroying invading bacteria and viruses

d) Are the most numerous circulating white blood cells

e) Rapidly respond to inflammatory and tissue injury sites

f) Neutropenia is defined as a decrease in the absolute neutrophil count or ANC

g) An ANC of 1,500 to 2,000 per cubic millimeter places the patient at moderate risk for developing an infection, while an ANC <500 per cubic millimeter places the patient at substantial risk for developing an infection

h) Other authorities suggest that an ANC of 500 to 1,000 per cubic millimeter places the patient at moderate risk for infection

2) Eosinophils

a) Increase during allergic reactions and parasitic conditions

b) Decrease when steroids are parenterally administered or during periods of stress

3) Basophils

a) Increase during the healing process

b) Decrease when steroids are parenterally administered or during periods of stress

b. Agranulocytes

1) Monocytes

2) Lymphocytes

1. Provided by granulocytes and monocytes

2. Neutrophils and monocytes are macrophages responsible for engulfing and partially digesting or phagocytizing the invading antigens

a. Neutrophils (bands and segments) predominate in the first hours of injury

b. Monocytes respond late during the acute phase of infection

1) Stronger action than neutrophils

2) Can ingest larger particles of debris

1. Formed by the B and T lymphocytes

2. Lymphocytes have specific antigen recognition

a. Neutralize bacterial endotoxins

b. Phagocytize invading bacteria and viruses

c. Increase with the occurrence of chronic and viral infections

1. Catheter-related bloodstream infection (CRBSI)

a. Not the same as catheter-associated bloodstream infection (CABSI) or central line-associated bloodstream infection (CLABSI)

b. Clinical definition is used when diagnosing and treating patients

c. Definition is not typically used for surveillance purposes

d. Requires specific laboratory testing that more thoroughly identifies the catheter as the source of the bloodstream infection

e. Problematic to precisely establish if a bloodstream infection is a CRBSI due to:

a. Clinical needs of the patient (e.g., the catheter is not always pulled)

b. Limited availability of microbiologic methods (e.g., many labs do not use quantitative blood cultures or differential time to positivity)

c. Procedural compliance by direct care personnel (e.g., specimen labeling must be accurate)

2. CLABSI

a. A term used by the Center for Disease Control and Prevention’s (CDC’s) National Healthcare Safety Network (NHSN) for surveillance definition

b. Surveillance definitions are really definitions for CABSI

c. Surveillance definition overestimates the true incidence of CRBSI because:

1) Not all bloodstream infections originate from a catheter

2) Some bloodstream infections are secondary to other sources other than the central line (e.g., pancreatitis, mucositis) that may not be easily recognized

1. Immunosuppression and immunodeficiency

2. Severe underlying chronic illness

a. Diabetes mellitus

b. Diseases that cause granulocytopenia

c. Other humoral or cellular immune states with neutrophil impairment, increasing a person’s susceptibility to infusion-related infection

3. Administration of multiple infusions

4. Extended hospitalization

5. Leukopenia (an abnormal decrease of white blood cells, usually below 5,000/mm³)

6. Presence of a concurrent infection

a. Urinary tract or respiratory infections

b. Hematogenous seeding when microorganisms migrate to the intravascular catheter from distant foci or if a catheter is inserted into a patient with a high-grade bacteremia or fungemia

7. Age

a. Infants younger than 1 year have an immature immune system

b. The older adult population (over 60 years of age) tends to exhibit a hyporesponsiveness to the invasion of foreign antibodies and may not exhibit the same signs and symptoms of infection, making the diagnosis of septicemia difficult

8. Burns

9. Therapeutic regimens

a. Antineoplastic therapy increases the risk of infection due to myelosuppression

b. Long-term parenteral nutrition due to the ability of microorganisms to translocate across the gastrointestinal tract into the mesenteric lymph system, spleen, liver, and vasculature

c. Corticosteroid therapy depresses the body’s immune system and decreases the body’s natural response to invading foreign proteins, permitting the invasion and multiplication of microorganisms

d. Antibiotic therapy, especially prolonged therapy, alters the body’s natural flora and predisposes the body to the development of an infection

1. Can occur when microorganisms are introduced into the infusion system by the administration of intravenous fluids

2. Most prevalent means of contamination

3. Primary causes of contamination

a. Improper hand hygiene by healthcare personnel

b. During compounding of admixtures

1) Improper use of laminar flow hoods

2) Use of malfunctioning laminar flow hoods

3) Incorrect use of admixing equipment, such as needles, syringes, or calibration devices that contaminate products

4) Failure to refrigerate admixed fluid containers

c. Improper aseptic technique while inserting a vascular access device (VAD)

1) Improper site preparation

2) Touch contamination of catheter or the prepared insertion site

3) Use of contaminated agents for the preparation of skin

4) Improper application of dressing

5) Failure to replace catheter insertion sites at the first sign of a complication (e.g., erythema, swelling)

6) Allowing a damp, soiled, or nonocclusive dressing to remain on the insertion site

d. During infusion system interventions/manipulations

1) Touch contamination of the administration set spike

2) Addition or touch contamination of add-on devices such as filters or extension sets

3) Addition or replacement of administration set(s)

4) During air removal from the administration set

5) Withdrawal of blood for laboratory specimens

6) Accidental disconnection of the administration set

7) Failure to maintain sterile, closed infusion system

8) Use of external devices to calibrate pressure monitoring systems

9) Administrations sets that are left in place too long, including blood administration sets, or residual blood in the administration set, may result in the proliferation of bacteria

10) Damp, soiled, or nonocclusive dressings left in place

11) Ointment at the insertion site (exception: hemodialysis catheters)

e. During medication administration

1) When medication is added to parenteral fluids

2) When secondary administration sets are not maintained as a closed system

3) During administration through injection/access ports of administration sets

4) When changing tubing or containers during administration of intermittent medication

5) When multidose vials are used, the potential for contamination increases

4. Primary causative organisms include, but are not limited to, the following:

a. Enterobacteriaceae (Enterobacter cloacae, Enterobacter agglomerans, Serratia marcescens, Klebsiella species)

b. Staphylococcus aureus

c. Coagulase-negative staphylococci

d. Fungi (Candida, Fusarium, Trichophyton, or Malassizia species)

e. Corynebacterium species

f. Pseudomonas aeruginosa

g. Serratia cepacia

5. Preventive strategies

a. Proper hand hygiene

b. Proper handling of infusates, including refrigeration when indicated

c. Careful examination of infusates

d. Careful admixture preparation

e. Careful handling of administration sets

f. Disinfection of injection ports/needleless connectors prior to each access

g. Strict aseptic technique when inserting catheters or changing dressings

h. Proper skin preparation of insertion sites

i. Remove Peripheral catheter at first sign of complications

j. Routine change of dressing, stabilization device, add-on devices, and administration set

k. Maintenance of dry, intact dressing on catheter insertion site

l. Maintaining a closed infusion system, whenever possible

m. Avoiding unnecessary manipulation of the infusion system

1. Occurs during the manufacturing process

a. Continuously monitored by industry and regulatory agencies

b. Sampling procedures devised to detect ongoing problems result in low levels of contamination

c. Sequential sampling procedures to monitor the production process

1) Rejection of products contaminated at unacceptable frequencies

2) Consideration of previous sterility testing results to determine the acceptability of current tests

2. Low rate of occurrence

a. An epidemic of infusion-related bacteremias possibly related to

1) Mass production of large volumes of intravenous solutions

2) Microorganisms in fluid containers that proliferate during storage

b. Nearly all reported septicemias are associated with contaminated infusate by aerobic gram-negative bacilli

c. Intrinsic contamination should be suspected in patients exhibiting signs and symptoms of septicemia who have no other apparent focus of infection

3. Primary causative organisms include, but are not limited to the following:

a. Enterobacteriaceae (Enterobacter cloacae, Enterobacter agglomerans, Serratia marcescens, Klebsiella species)

b. Nonaeruginose pseudomonades, particularly Pseudomonas cepacia and Pseudomonas maltophilia, or by the Citrobacter species

4. Preventive strategies

a. Stringent quality control during the manufacturing process

b. Careful examination of intravenous fluid containers and packaging before use for

1) Puncture holes, cracks, tears, or leaks

2) Apparent moisture

3) Loss of vacuum

4) Damage to bag, bottle closures, missing or improperly fitting port covers, protective seals, and coverings

5) Beyond-use date or expiration date surpassed

6) Clarity and particulate matter

5. Isolation of lot(s) of suspected contaminated products

6. Documentation and reporting mechanisms for contamination

a. If potential contamination is suspected, promptly report to:

1) Infusion therapy manager

2) Pharmacist

3) Materials management

4) Risk management

5) Licensed independent practitioner (LIP)

b. Immediate notification of authoritative bodies

1) Local, state, and federal authorities

2) CDC

3) Food and Drug Administration (FDA)

1. Caused by transmission of organisms from sources other than the patient; can be from the healthcare workers’ hands, nose, clothing, or other contaminated objects

2. Frequent occurrences

3. Primary causative organisms include, but are not limited to the following:

a. Staphylococcus aureus

b. Coagulase-negative staphylococci

c. Staphylococcus epidermidis

d. Pseudomonas aeruginosa

e. Enterococcus

f. Candida species

4. Preventive strategies

a. Proper hand hygiene

b. Strict adherence to aseptic technique

c. Use of barrier protection, such as gloves, face masks, and disposable gowns

1. Caused by patient’s own microflora

2. Two sources of endogenous infections

a. Primary endogenous infections

1) Caused by the patient’s own flora (e.g. placement of a tunneled catheter exit site near a patient’s tracheostomy site may result in a catheter infection from migration of the patient’s own flora around the tracheostomy)

2) Intravenous catheter can become colonized by microorganisms from a distant site of infection

b. Secondary endogenous infections

1) Caused by modification of the patient’s own flora following prolonged antibiotic administration

2) Colonization with healthcare setting flora

3. Patients who are immunocompromised are more susceptible

4. Some microorganisms can translocate across the gastrointestinal tract to normally sterile tissues, such as the mesenteric lymph nodes, spleen, liver, and blood

5. A variety of microorganisms associated with the flora of the skin are commonly involved

6. Primary causative organisms include, but are not limited to, the following:

a. Staphylococcus aureus

b. Staphylococcus epidermidis

c. Escherichia coli

d. Candida species

7. Preventive strategies

a. Proper hand hygiene

b. Proper site preparation

c. Strict adherence to aseptic technique

d. Use of appropriate antimicrobial solutions

e. Replace or remove peripheral catheter upon first sign of complications

f. Proper technique for preparing intravenous sites

g. Changing dressings that have become compromised, damp, or soiled

h. Proper disinfection of injection ports/needleless connectors and systems connections

i. Use of disinfection caps on needleless connectors

1. Gram-negative organisms are the most common pathogens found in contaminated infusate

2. Klebsiella and Escherichia coli, which are primarily transmitted from hand and food contamination; and Pseudomonas aeruginosa, recognized by green, foul smelling exudates at the insertion or exit site

3. Klebsiella and Enterobacter aerugenes exhibit rapid growth in dextrose solutions, whereas Pseudomonas cepacia, Pseudomonas aerugenes, and Serratia grow in distilled water

4. Saline solutions support the growth of most organisms, but poorly support the growth of Candida

5. Crystalline amino acids with 25% dextrose solutions support the growth of Candida, although slowly

6. 10% lipid emulsions have been shown to support the rapid growth of Candida

7. Blood products

a. Contamination of blood products occurs rarely; only 1% to 6% of blood units show small amounts of microorganisms

b. Blood and blood products may be contaminated at the collection site, during the actual collection procedure, during the separation process into components, or during transport and storage

c. Blood collection sets may be contaminated during the manufacturing process

d. Storage time and temperature of the blood or blood products are directly related to the growth of microorganisms

e. Sepsis from contaminated blood products is related to the endotoxins produced by psychrophillic (or cold-growing) gram-negative bacteria

f. Pseudomonas species, Citrobacter, Freundii, Escherichia coli, and Yesinia enterocolitica are the most common pathogens associated with endotoxin production

g. The resulting transfusion reaction produces overwhelming shock and a high mortality rate because of the massive numbers of pathogens present in the contaminated unit

1. Gram-positive organisms, especially Staphylococcus aureus and Enterococcus, are the most frequently involved pathogens in catheter-related infections and sepsis

2. Enterococcal infections have become extremely difficult to treat with the emergence of vancomycin-resistant enterococcus

3. Staphylococcus aureus is the most common gram-positive organism causing septicemia

4. Staphylococcus aureus is carried and transmitted on the hands of healthcare workers or is colonized on the patient’s skin, migrating on the catheter surface into the bloodstream at the catheter’s insertion site

5. The causal agent in approximately two-thirds of infusion-related infections

6. Attach themselves to the inner and outer surfaces of intravenous catheters, grow and proliferate even in the absence of externally supplied nutrients

7. Produce a glycocalyx solution called slime, which protects the microorganisms by providing resistance to the natural immune mechanisms of the body, and even to prolonged high-dose antibiotic therapy

1. The most frequently identified pathogen associated with fungemias is Candida albicans

2. Central vascular access devices (CVADs) are the most likely sources of this pathogen

3. Focal retinal lesions known as cotton-wool spots are commonly seen in patients with severe Candida infections, even without positive blood cultures

4. Careful ophthalmologic examinations should be performed on patients with suspected catheter-related fungemia, especially those patients receiving parenteral nutrition

1. Susceptibility to infection

a. Leukopenia

b. Presence of concurrent infection

c. Severe underlying chronic illness

d. Age

e. Burns

2. Method of site preparation

a. Not using appropriate antiseptic solutions

b. Improper technique

3. Method of insertion

a. Technical skill of the clinician placing the venous access device

b. Improper aseptic technique during catheter insertion

c. Inadequate barrier protection

d. Inadvertent contamination

4. Type of catheter and material

a. Larger, stiffer catheters provoke thrombogenesis, an inflammatory response, which facilitates colonization

b. Polyurethane and silicone catheter materials are softer and less thrombogenic

c. Candida species and coagulase-negative staphylococcus have been shown to better adhere to catheters made of polyvinylchloride than to those made of polytetrafluoroethylene

d. Catheters with silver ion impregnated cuffs have been shown to prevent the migration of bacteria and fungi along the external surface of the catheter, preventing colonization

5. Catheter location

a. Peripherally placed access devices pose a substantially lower risk of septicemia than nontunneled CVADs

b. Skin of the upper and lower extremities has a lower temperature than the trunk or neck

6. Residual blood left in the infusion system

7. Use of multilumen catheters

a. Patients with multilumen catheters are generally sicker, may be receiving parenteral nutrition, may be immunocompromised, will probably have extended hospital stays, and have their infusion systems accessed and manipulated more frequently

8. Fibrin sheaths

a. Form within hours after insertion of a catheter

b. May be a protective mechanism or may be a nidus for infection

c. Promotes bacterial adherence and increases bacterial replication around the catheter

d. Formation prevention interventions under investigation include the use of antibiotic locks, prophylactic use of antibiotics, alternative flush solutions, and prophylactic use of thrombolytic drugs

9. Migration of bacteria through the subcutaneous catheter tract

10. Contamination of infusion system

11. Hematogenous seeding from a concurrent source of infection

12. Biofilm attachment and growth to the intravascular portion of the catheter may promote bacterial adherence, replication, and detachment of microbes

13. Longer catheter dwell time may increase colonization of microorganisms

14. Colonization of microorganisms on the catheter hub

15. Long-term antimicrobial therapy alters the normal flora of the skin

1. Colonization of microorganisms at the insertion site is associated with the highest incidence of catheter-related infections

2. Normal skin flora

a. Serves as one of the main sources of bacteria responsible for infusion-associated infection and sepsis

b. Can colonize on catheter hubs, system connections, and insertion sites, especially if moisture is allowed to accumulate under the site dressing

3. Microorganisms of the skin are classified as either resident (permanent) or transient flora

a. Resident flora is referred to as colonizing flora

1) Considered to be permanent residents of the skin

2) Not readily removed by mechanical friction

3) Permanent skin flora organisms include, but are not limited to, the following:

a) Staphylococcus epidermidis

b) Staphylococcus aureus

c) Corynebacterium (commonly referred to as diphtheroids or coryneforms)

d) Klebsiella-Enterobacter group

b. Transient flora is referred to as contaminating or noncolonizing flora

1) Microorganisms not consistently present on most persons

2) Loosely attached to the skin, varying in quantity from day to day

3) Readily transmitted by the hands of healthcare workers

4) Removed when proper hand hygiene is performed

1. Peripheral

a. Lowest risk of infection with short peripheral catheters, and Teflon or polyurethane peripheral VADs

b. Change VAD inserted in an emergency (emergency-inserted catheter) when patient is in stable condition or within 48 hours of catheter insertion; replace with a catheter inserted in a new location

c. Appropriate site selection

1) Adults: use an upper extremity site for catheter insertion. Replace a catheter inserted in a lower extremity site to an upper extremity site as soon as possible

2) Pediatric patients: use the upper or lower extremities or the scalp (in neonates or young infants) as the catheter insertion site