Pediatric Healthcare: Infection Epidemiology, Prevention and Control, and Antimicrobial Stewardship

Host or Intrinsic Factors

PICUs, NICUs, oncology services, and gastroenterology services caring for patients with intestinal failure who are dependent on total parenteral nutrition (including lipids) have the highest rates of bacterial and fungal infection associated with central venous catheters. The definition of mucosal barrier injury laboratory-confirmed bloodstream infection (MBI-LCBI) currently is used by the National Healthcare Safety Network (NHSN) of the CDC to distinguish bacteremia that represents translocation of gut microorganisms related to mucosal barrier injury in patients with oncologic conditions, hematopoietic stem cell transplantation (HSCT), and intestinal failure from bacteremia associated with central venous catheters (CLABSI) and are not publicly reported. This distinction is important because the bundled practices that focus on line insertion and maintenance do not prevent MBI-LCBI. HAIs can result in substantial morbidity and mortality, as well as lifetime physical, neurologic, and developmental disabilities. Host (i.e., intrinsic) factors that make children particularly vulnerable to infection include immaturity of the immune system, congenital abnormalities, and congenital or acquired immunodeficiencies. Children with congenital anomalies and developmental disabilities have an increased risk of HAI because their unique anatomic features predispose them to contamination of normally sterile sites, and their physiologic functions may be impaired. Moreover, these children require prolonged and repeated hospitalizations, undergo many complex surgical procedures, and have extended exposure to invasive supportive and monitoring equipment.

Innate deficiencies of the immune system in prematurely born infants, who may be hospitalized for prolonged periods and exposed to intensive monitoring, supportive therapies, and invasive procedures, contribute to the relatively high rates of infection in the NICU. All components of the immune system are compromised in neonates, and the degree of deficiency is proportional inversely to gestational age (see Chapter 9 ). The underdeveloped skin of the very low birth weight (<1000 g) infant provides another mode of pathogen entry.

Populations of immunosuppressed children have expanded with the advent of more intense and innovative immunosuppressive therapeutic regimens used for oncologic conditions, HSCT, solid-organ transplantation, and rheumatologic conditions and inflammatory bowel disease for which immunosuppressive drugs and biologic response modifying agents are used. Genetic mutations in the genes for the transmembrane conductance regulator (CFTR) in children with cystic fibrosis result in thick secretions, chronic endobronchial infections, and gastrointestinal malabsorption. Knowledge of the epidemiology of infection of patients with cystic fibrosis and effective methods to prevent patient-to-patient transmission have expanded with the use of newer molecular diagnostic methods; a guideline for prevention of transmission of infectious agents of particular concern for this population was developed and updated. Fortunately, the population of children with perinatally acquired HIV infection and AIDS has decreased dramatically since 1994, but new cases of sexually transmitted HIV infection continue to be diagnosed in teens who receive care in children’s hospitals; therefore, HIV screening is an important routine practice for those >13–15 years of age. Additionally, young infants who have not yet been immunized, or immunosuppressed children who do not respond to vaccines or who lose antibody during disease or treatment (e.g., patients with nephrotic syndrome), have increased susceptibility to vaccine-preventable diseases.

Sources or Extrinsic Factors

The source of many HAIs is the endogenous flora of the patient. A colonizing pathogen can invade a patient’s bloodstream or be transmitted to other patients on the hands of healthcare personnel (HCP) or on shared equipment. Water can be an important source of infections caused by gram-negative bacilli (GNB); therefore, exposure of wounds or mucous membranes to tap water should be avoided in high risk hospitalized patients. Other important sources of HAIs in infants and children include the mother in the case of neonates, invasive monitoring and supportive equipment, contaminated infusates such as blood, total parenteral nutrition fluids, lipids, and infant formula, nutritional supplements, and human milk. Intrinsically contaminated powdered formulas and infant formulas prepared in contaminated blenders or improperly stored or handled have resulted in sporadic and epidemic infections in the nursery (e.g., Cronobacter sakazakii ), but such infections have become less frequent since the pathogenesis was defined and contamination reduced. Human milk that has been contaminated by maternal flora or by organisms transmitted through breast pumps has caused isolated serious infections and outbreaks. The risks of neonatal hepatitis, cytomegalovirus (CMV) infection, and HIV infection from human milk warrant further caution for handling and use of banked breast milk.

Maternal infection with Neisseria gonorrhoeae, Treponema pallidum, HIV, hepatitis B virus, parvovirus B19, Mycobacterium tuberculosis, herpes simplex virus, group B Streptococcus , or colonization with multidrug-resistant organisms (MDROs) poses substantial threats to the neonate. Group B Streptococcus is rarely transmitted nosocomially and is prevented by following recommended screening and prophylaxis protocols. During perinatal care, procedures such as fetal monitoring using scalp electrodes, fetal transfusion and surgical procedures, umbilical cannulation, and circumcision are potential risk factors for infection. Other contacts, including adult and sibling visitors, may introduce RSV and vaccine preventable infections into pediatric healthcare settings.

The use of invasive devices for monitoring or treatment is associated with an increased infection risk, and devices should be used only for the period of time when necessary and according to evidence based protocols for insertion and care. With increasing numbers of procedures being performed by pediatric interventional radiologists, an understanding of appropriate aseptic technique, as well as prevention and management of infectious complications, by interventional radiologists is important.

Construction, renovation, demolition, and excavation in and near healthcare facilities and contaminated linen are important sources of environmental fungi (e.g., Aspergillus spp., agents of mucormycoses, Fusarium spp., Scedosporium spp., Bipolaris spp.), but these pathogens are not transmitted patient to patient. Immunocompromised patients, and patients in the PICU are at greatest risk for fungal infection, and case fatality rates may be ≥50%, especially if diagnosis and treatment are delayed. Infection control risk assessments and implementation of effective practices can prevent exposure to these pathogens.

Several practices must be evaluated with respect to the potentially associated risk of infection for infants and young children. Theoretical concerns exist that infection risk also will increase in association with the innovative skin-to-skin practices (kangaroo Care) and co-bedding of twins. The experience with skin-to-skin practices has been safe and beneficial as long as parents are advised about potential risks if they have an infection. Neither the benefits nor the safety of co-bedding multiple-birth infants in the hospital setting has been demonstrated.

Routes

The principal modes of transmission of infectious agents are through direct and indirect contact, droplet, and airborne routes. ^, Many pathogens can be transmitted by more than one route. During the 2020 pandemic of SARS-CoV-2, additional evidence has been published to support aerosol transmission as an important mode of transmission that varies from traditional droplet or airborne routes. Whole genome sequencing has become a critically important tool in outbreak investigations of bacteria, fungi, and viruses to define routes of transmission more precisely and is now available widely.

Role of Healthcare Personnel

Transmission of microbes between children and HCP when recommended hand hygiene is not performed is an especially important risk because of the very close contact that occurs during care of infants and young children. HCP as vehicles of infectious agents is facilitated by overcrowding, understaffing, and too few appropriately trained nurses in pediatric facilities. ^, Adequate staffing levels and the composition of staff in high-risk clinical units are important components of an effective IPC program. HCP rarely are the source of outbreaks of HAIs caused by bacteria and fungi and, therefore, performing screening cultures among HCP as part of an outbreak investigation rarely is indicated. Observations of HCP for specific risk factors (e.g., dermatitis, skin abscesses, onychomycosis, wearing of artificial nails) and querying about the presence of conditions (e.g., sinusitis, draining otitis externa, respiratory tract infections) that may increase the risk of transmission is more helpful than performing widespread cultures of hand swabs during an outbreak investigation unless there is a specific epidemiologic link. Persons with direct patient contact who were wearing artificial nails have been implicated in outbreaks of P. aeruginosa and ESBL-producing Klebsiella pneumoniae in NICUs; therefore, the use of artificial nails or extenders is prohibited in persons who have direct contact with high-risk patients. Several published studies have shown that infected pediatric HCP, including resident physicians, transmitted Bordetella pertussis to patients and can be the source of other vaccine-preventable infections in healthcare.