INFECTIONS IN CANCER CENTRE PATIENTS

Cancer center patients are frequently immunosuppressed and at risk for a wide range of pathogens. A good infection prevention program is extremely important to reduce risks of both community-acquired infections and hospital-acquired infections (HAIs). Basic measures such as hand hygiene, transmission-based precautions, environmental hygiene, aseptic technique, HAI “bundles,” and antimicrobial stewardship are essential components of any infection prevention program, and the cancer center is no exception.

Hygiene

Proper hygiene is important in preventing infections in all patients, especially those with profound immunosuppression. Skin inspection should be done routinely with attention to sites at high risk for infection (eg, in- travascular catheters, perineum); in our institution this is performed daily during nursing care with physician follow-up as needed. Expert recommendations include avoiding tampon use for menstruating hematopoietic stem cell transplant (HSCT) recipients as well as avoid- ing digital rectal examinations, rectal thermometers, enemas, and suppositories during periods of neutrope- nia to prevent mucosal breakdown. There are in- creasing data to support the use of daily chlorhexidine bathing, particularly in critically ill patients, to reduce transmission of multidrug-resistant organisms (MDROs) and prevent infections. A recent randomized clus- ter trial in 9 intensive care units and 1 bone marrow transplant unit demonstrated a 23% reduction in MDRO acquisition and a 28% reduction in hospital- associated bloodstream infections with daily chlorhexi- dine bathing. Additional studies are needed to determine if this is an effective strategy in the general cancer center population. 

Because the oral cavity is an important source of potentially pathogenic bacteria, stringent periodontal health is important. Complete periodontal examination followed by necessary treatment is recommended before management of head and neck cancers, high-dose chemotherapy, HSCT and any cancer regimen that is expected to lead to significant immunosuppression. Routine oral hygiene is important to minimize infections (eg, pneumonia) and may improve healing of mucositis. Oral rinses with sterile water or normal saline are recommended 4–6 times per day and neutropenic patients should routinely brush their teeth, taking care to minimize gingival trauma.

Low Microbial Diet

The Centers for Disease Control and Prevention (CDC) recom- mends a low microbial diet for HSCT recipients. There are no guidelines for the use of a low microbial diet in other patients; however, many centers will prescribe one for patients with hematologic malignancies during periods of neutropenia. Theoretically, reducing exposure to microbes in foods such as unpasteurized cheeses or beverages, raw fruits and vegetables, and undercooked meats during periods of neutropenia may de- crease the incidence of infection.

Device-Associated Infections

Because of the unique needs of cancer patients, intravascular catheters, particularly tunneled or implantable catheters, are used more often and for longer durations in these compared to other hospitalized patients as catheters provide long-term access for frequent blood draws and infusion of chemotherapy and blood products. Thus, these patients are at particular risk for catheter-related complications including infections. Catheter-related infections are more common with the use of nontunneled central venous catheters (CVCs). No cath- eters, however, are without risk. In a recent prospective obser- vational cohort study of all adult patients requiring a CVC in a cancer unit, the rate of central line–associated bloodstream in- fection (CLABSI) per 1000 line-days was 2.50. CVC type was a risk factor, greatest for nontunneled lines (hazard ratio [HR], 3.50; P < .0001) and tunneled lines (HR, 1.77; P ≤ .011) compared to peripherally inserted central venous catheter lines. In theory, the best way to prevent catheter-related complica- tions is to minimize catheter use; however, this is often not fea- sible. Regardless, the need for catheters should be reassessed regularly and catheters removed when no longer needed.

There are few published data regarding the frequency of use of urinary catheters or the incidence of catheter-associated urinary tract infections (CAUTI) in the cancer center popula- tion. Regardless, implementation of strategies aimed at reduc- ing CAUTI is prudent for those patients requiring urinary catheterization. These strategies include ensuring appropriate catheter use, including removal when no longer necessary, use of aseptic technique during insertion, and maintaining a closed-drainage system with unobstructed flow.

Community Respiratory Viruses

Infection with common community respiratory viruses can lead to serious disease and significant morbidity and mortality among patients with cancer, especially HSCT recipients. Given the potential adverse outcomes and the relative ease of spread of infection, healthcare-associated and household transmission is a serious concern. Significant effort to prevent and control the spread of these infections should be made. Acute viral respiratory infections are most commonly due to respiratory syncytial virus, influenza viruses, rhinoviruses, parainfluenza viruses, human metapneumoviruses, coronaviruses, and adenoviruses and typically reflect disease activity in the community. Rhinoviruses, coronaviruses, and adenovi- ruses are the most commonly encountered. However, immunosuppressed patients may present with atypical lower respiratory tract disease (in addition to typical upper tract disease), and the incidence of lower respiratory tract infection is higher with respiratory syncytial virus, influenza viruses, parainfluenza viruses, human metapneumoviruses, and adeno- viruses. Early studies suggested that nearly half of cancer patients (HSCT recipients and leukemia patients) infected with these viruses progress to viral pneumonia with a mortality rate of >50%. An effective infection prevention strategy includes vaccination (influenza); community outbreak surveillance; hospital surveillance for nosocomial transmission outbreaks; patient and personnel education regarding disease recognition, prevention strategies, and modes of transmission; rapid diagnosis with early isolation for suspected and confirmed cases; and restriction of potentially infected visitors and healthcare personnel from the cancer center.

Fungal Pneumonia

Invasive pulmonary aspergillosis and other fungal pneumonias are a serious concern, particularly in patients with prolonged neutropenia or HSCT recipients. Aspergillus species are responsible for a majority of invasive fungal infections among cancer patients; and, although decreased in recent years, mor- tality remains high. Aspergillus is ubiquitous in the environment, including hospital water supplies; infection occurs primarily through inhalation of conidia. Multidrug-Resistant Organisms Historically, cancer centers used surveillance cultures of the skin or perirectal areas to guide empiric antibiotic therapy for patients with neutropenic fevers. Many centers discontinued this practice due to the lack of supporting data and cost. The role of surveillance culture for MDROs (eg, vancomycin- resistant enterococci, methicillin-resistant Staphylococcus aureus, and multidrug-resistant gram-negative organisms) has yet to be well defined in the cancer center. Yet, many advocate for the use of MDRO surveillance, particularly in high-risk patients (eg, HSCT or acute leukemia).

Transmissible Diseases From Visitors and Healthcare Personnel Leukemia patients and HSCT recipients often have prolonged hospitalizations. They may have a large number of visitors both in the hospital and at home while still profoundly immunosuppressed. All visitors should be instructed on basic infection pre- vention including hand hygiene techniques and isolation procedures. In the hospital, a system should be established whereby all visitors can be screened for potential transmissible diseases . The CDC recommends that any visitor with an upper respiratory tract infection, a flu-like illness, a herpes zoster rash (whether covered or not), or recent known exposure to any transmittable disease should not be allowed access to the unit or should at least be restricted from visiting severely im- munosuppressed patients. Healthcare personnel with a disease trans- mitted by air, droplet, or direct contact should be restricted from direct patient contact.

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