Chapter 5. Infection Control in the Hospital

Hand hygiene is the most important infection-control practice, whether in the hospital, the clinic, or at home. By interrupting the transmission of pathogens, hand hygiene protects not only patients, but also the health care workers (HCWs) who care for them. Monitoring and encouraging compliance with proper hand hygiene is one of the most important goals of every infection control program.

Human skin is naturally colonized with bacteria; our hands have been estimated to have approximately 4 million bacteria/cm2 of skin, mostly coagulase-negative staphylococci and diptheroids.1–3 After admission to hospital, patients become colonized with different, more pathogenic organisms, some acquired in hospital, others brought from the community but increasing in number by stress of illness and antibiotic treatment.4,5 These bacteria can become the source of nosocomial infections. After caring for a hospitalized patient, the hands of a HCW become contaminated with these “transient flora,”6 which can then be passed onto the next patient cared for, to a chart, phone, or computer, unless removed by hand hygiene.7 The deeper resident flora remains mostly intact.8 Viral pathogens such as the respiratory syncytial virus (RSV) and rotavirus are also transmitted to the hands of HCWs during direct patient care,9 and also by contact with fomites in the room. Hence, hand hygiene is crucial not only after touching a patient but also after entering a hospital room and handling objects in the room.

Gloves are used to decrease the risk of transmission of pathogens to hands of HCWs and have an important role in infection-control guidelines. However, gloves do not completely prevent transmission of organisms to our hands.10 It is, therefore, necessary to clean hands after removing gloves and to change gloves when going from an infected site to a “clean” site.

Artificial nails can become colonized with gram-negative bacteria,11,12 and should not be allowed for HCWs involved in direct patient care. In the nursery, rings are removed prior to washing hands on entering the nursery and should remain off until finished with direct patient care.13 While at least one study has suggested that alcohol-based rubs are not adversely affected by the presence of rings,14 other studies raise concern about the ability to remove bacteria adequately when rings are left on during hand hygiene.13

From Semmelweis’ observation that hand hygiene could decrease the risk of puerperal fever and maternal death in an obstetrical ward in 1847, to a recent study showing decreased catheter-related bacteremia with attention to hand hygiene and infection-control guidelines,15 hand hygiene really does save lives.

How Do We Do Hand Hygiene?

Soaps are detergents that remove organic substances and soiling materials from the hands, removing pathogens mechanically. Plain soaps without any antimicrobial additives reduce the burden of bacteria on the skin. A 15-second handwash can reduce the number of pathogenic bacteria on the skin by 0.6–1.1 log10.1,16 However, bar soaps can become colonized with gram-negative bacteria and can become a fomite for spread of pathogens.17 Antimicrobial agents have been added to soaps and most hospitals now use antimicrobial liquid-dispensed soaps to avoid this problem. The most common antimicrobial additives in soaps are triclosan and chlorhexidine, which act to destabilize the cytoplasmic membrane of bacteria and yeast. Chlorhexidine also has excellent activity against enveloped viruses like HIV, HSV, RSV, influenza, and hepatitis viruses. Technique is important to be effective (Table 5–1).

In contrast to soaps, alcohol-based hand rubs operate primarily by denaturing proteins contained in microbes. Most commercial rubs contain ethanol, n-propanolol, or isopropanolol alcohol at varying concentrations. The most effective concentration of alcohol is between 60% and 95%.18 At these concentrations, alcohols have activity against gram-positive bacteria, including MRSA and VRE, various gram-negative bacteria, fungi, mycobacteria, HSV, HIV, influenza virus, RSV, hepatitis B virus, hepatitis C virus, and rotavirus. Alcohols are not effective in destroying the spores of Clostridium difficile, protozoal oocysts and are not effective in cleaning visibly soiled hands; mechanical removal by soap and water is therefore recommended after contact with these infections.

Numerous studies, using various methods19,20 have documented that alcohol-based hand rubs are effective, and many studies suggest increased efficacy compared to soap and water.21 Newer hand rub products have added emollients and are much better tolerated than earlier products that dried the skin and were not well accepted. Nurses who use an alcohol rub compared to those using soap and water have less drying and cracking of the skin.22,23 Additionally, studies have shown improved compliance with hand hygiene when hand rubs are made available to HCWs, as they are faster and easier to use effectively, and can be placed in areas where getting to a sink is difficult.24

Despite the importance of hand hygiene, many studies continue to show poor compliance with hand hygiene in most hospitals in this country. Important reasons that HCWs fail to comply with hand hygiene include overwork and a sense of not having enough time25; lack of role models (“if my attending physician doesn't clean his hands, why should I?”); and lack of understanding the need to use hand hygiene, especially after removing gloves. In response to these considerations and the increasing data that alcohol rubs improve compliance, the CDC in 2002 revised guidelines for hand hygiene and for the first time stressed the use of hand rubs (Table 5–2).21

Infection Control and Supporting Hand Hygiene

Methods to support and to promote hand hygiene include education, to be sure that every HCW understands proper hand hygiene; observation of hand hygiene practice with feedback and corrective action, if practice does not improve; placing more hand rubs in places where sinks are difficult to reach; educating patients and families and engaging their support in hand hygiene promotions; institutional role models and a commitment to safety within the institution. (Recommendations are reviewed in detail in reference 21 and at the Institute for Healthcare Improvement (IHI): How-to Guide: Improving Hand Hygiene: www.IHI.org). Hand hygiene is a constant concern and promoting it is necessary as part of each hospital's infection-control and safety programs.

Isolation Precautions

All hospitalized patients should be handled with standard precautions, as outlined by the CDC Health Care Infection Control Practices Advisory Committee. These guidelines recognize that not only blood but also other body fluids pose a risk of carrying pathogens and that all patients should be treated in a consistent manner to decrease the risk of transmission of these pathogens between patients and HCWs. Standard precautions are based on the following basic assumptions:

1. Hand hygiene is the most important infection-control practice—the basis of all precautions including standard precautions.

2. Barrier techniques help to avoid contact with any body fluid or mucosal surface to decrease transmission of pathogens and include Gloves, gowns, mask, and eye protection or face shield as appropriate for patient contact.

Standard precautions for pediatrics are summarized in Table 5–3.

Transmission-Based Precautions

More specialized precautions are used to prevent the spread of specific microorganisms when standard precautions are not sufficient. The types of transmission-based precautions are airborne, droplet, and contact precautions (Table 5–4).

Airborne precautions are employed for infectious agents spread primarily by the droplet route, such as Mycobacterium tuberculosis, varicella zoster virus, and the measles virus. These organisms are carried on small-particle droplets or dust in the air, remaining suspended for long periods of time, and are subject to spread based on airflow. They can be spread over long distances, and require special ventilation and air handling. Patients should be given a private room with negative air pressure ventilation system that exhausts air externally or filter it through a high-efficiency particulate (HEPA) filter prior to recirculation. If a private room is not possible, patients with the same infectious agent should be cohorted. HCWs susceptible to infection with measles or varicella virus should not care for these patients. If susceptible workers must care for these children, a mask should be worn when in the room. Workers with immunity to measles or varicella do not require masks. N-95 masks, or other sealed respirators should be used in the care of patients with suspected or known cavitary pulmonary tuberculosis. HCWs require “fit” testing, to be sure that the mask selected is properly fit and will be protective, prior to using in the care of patients.

Droplet precautions are used for organisms with transmission by aerosols from activities such as talking or sneezing. Aerosols deposited on the mucous membranes of another individual transmit infection. These larger droplets spread only over a more limited range of less than 3 ft, compared to airborne organisms. Since these microorganisms are contained in large droplets, they are not readily spread by air currents and therefore do not require negative pressure rooms with high-efficiency particulate filters or outside exhausts. In general, patients with an organism spread by droplet transmission should be given a private room. If a private room is not available, cohorting patients with the same infection is acceptable. If neither of these solutions is possible, then infected patients must be separated from their roommates by a distance of at least 3 ft. HCWs entering the room should wear masks to prevent infection when in close contact with the patient, within 3 ft. Masks should be removed and left in the room or anteroom, with hand hygiene after removing the mask. Organisms that require droplet precautions include adenovirus, diphtheria (pharyngeal), invasive Haemophilus type b, Influenza, mumps, Neisseria meningiditis, parvovirus prior to rash, pertussis, rubella, streptococcal respiratory infections, and the SARS virus.

Contact precaution is used to prevent both direct and indirect contact transmission. Direct contact transmission occurs when microorganisms are transferred from a patient to a HCW or another patient directly by direct contact (e.g., patient to hand of HCW). In contrast, indirect contact transmission occurs when the spread is via an intermediate object, such as when a HCW touches contaminated linens or bed surfaces and his hands become contaminated. Hand hygiene and barrier methods are particularly important in preventing the spread of these organisms. Patients should be given a private room, or cohorted with other patients with the same infection, and gloves should be worn at all times. If a HCW is likely to have contact with a patient's clothing or with surfaces in the patient's room, gowns should be worn and removed with gloves prior to leaving the room (or in an anteroom) and then hand hygiene. Organisms requiring this isolation include C. difficile, conjunctivitis, enteroviruses, Escherichia coli O157:H7, hepatitis A, herpes simplex virus: neonatal and cutaneous herpes zoster shingles, parainfluenza virus, RSV, rotavirus, scabies, Shigella, and Staphylococcus aureus draining wounds.

When the etiology of the infection is unknown, the transmission precautions can be used empirically and can be used in combination. For example, infants who are clinically diagnosed with bronchiolitis should be placed in both droplet and contact precautions if and until their specific pathogen is known. Similarly, pediatric patients with a diarrheal illness that is likely to be infectious should be placed in contact precautions.

Children placed in transmission-based precautions should not be allowed to leave their rooms for visits to the cafeteria or play rooms. Gloves are not required for routine diaper changes unless the child is in contact isolation. A full listing of organisms with isolation recommendations and incubation periods is available at the CDC Web site: www.cdc.gov/ncidod/dhqp/gl_isolation.

Consoderations for Staff in Children's Units

HCWs should be screened by serology for vaccine-preventable infections and vaccine offered at the time of employment; infections include varicella zoster, measles, rubella, and mumps in addition to hepatitis B. The Tdap vaccine released in 2006 against tetanus, diphtheria, and pertussis should be given to employees 19–65 years of age if they have not received a tetanus booster in the last 2 years or when due for a booster. Yearly vaccination with the influenza virus vaccine should be standard. This vaccine can be given on hospital units, increasing compliance with this important recommendation. HCWs should also be evaluated for tuberculosis yearly, more frequently in high-risk areas. HCWs should be encouraged to stay at home and to avoid direct patient care when they are ill. They should be educated about the devastating effects that mild adult diseases, such as an upper respiratory infection or gastroenteritis, may have on children, especially infants and newborns.

Sibling Visitation

Visitation rules should complement isolation and safety procedures. In pediatric hospitals, family and sibling visits are important to the well-being of patients, but can also be a source of infectious diseases. Siblings should be evaluated outside the ward or intensive care unit by a trained HCW to evaluate each child for symptoms of contagious diseases and history of exposure to a contact with a known contagious disease to which the child is susceptible. Siblings should be excluded from visiting if they have fevers or symptoms of upper respiratory infection, gastroenteritis, or communicable viral exanthema. Some hospitals have utilized a sticker system that notifies the hospital staff that the visiting sibling has been screened and hence is wearing a specified sticker (e.g., green sticker for go).

Pet and Service Animal Visitations

An effective animal visitation policy involving allergic reactions, zoonotic transmission of infection, emotional reactions to the animals must be taken into account.26 Pets should have documentation of their vaccinations and a certification from the attending veterinarian that the animals are free from disease and appropriate for visiting. Three types of animals are eligible for visits: personal pets, therapeutic animals, and service animals. Only canines and felines are eligible for visitation in the hospital. Children who have indwelling catheters in place should have these devices covered when interacting with the animal. In addition, the animals should be confined to the specific areas and in general, should not be allowed entry into intensive care units or nurseries.

Service animals differ from pets or therapeutic animals in that their presence is necessary to allow the disabled to perform daily tasks.27 These animals, usually a professionally trained dog, have a role that has been legally defined by the Americans with Disabilities Act. As such, exclusionary rules may not apply as a matter of law. In general, all public facilities must allow service animals to accompany disabled citizens. Service animals may be barred from certain areas of the hospital if their presence would result in a danger to patients or a change in hospital functioning.

Infection Control in the Neonatal Intensive Care Unit

There is no more concerning site for infection control in the hospital than the Neonatal Intensive Care Unit (NICU), the site with the highest rate of nosocomial infections.28 Neonates, and especially the premature neonate, are immuno-compromised hosts. In the NICU, infants are likely to have underlying medical disease often requiring prolonged hospital stays with invasive procedures and indwelling catheters. The premature infant may also have immature skin, those born before 32-weeks gestation have relatively permeable skin for the first 2 weeks after birth, allowing for the translocation of bacteria across the skin, with resultant transient bacteremias. In a similar manner, the mucosa of the mouth and gastrointestinal tract are underdeveloped and can allow translocation of organisms. The GI tract and upper airway at birth are sterile, becoming colonized with bacteria from the environment, normally that of the mother. If a child is critically ill and is in ICU, the flora is likely to be the more pathogenic flora of the hospital,4 and even community-acquired flora will be pressured by antibiotic therapy toward more resistant organisms.29 The immune system of the neonate is immature with decreased neutrophil reserves and neutrophil chemotactic function; immaturity of T-cell function, as well as defects in the complement cascade.30 Transplacental transmission of immunoglobulin G (IgG) occurs during the last trimester so the immature infant born before 32-weeks gestation is deficient. The newborn has a blunted immunoglobulin response and frequent blood draws in the NICU deplete stores of IgM and IgG, while frequent blood transfusions dilute immunoglobulin levels. Together these factors make the newborn, and especially the very immature infant, at risk for infection.

Outbreaks are a constant concern in the NICU. Hand contamination of the HCW can occur even with routine patient care and allows transmission between infants unless hand hygiene is meticulous between patients.31,32 A pathogen of increasing concern in the NICU is methicillin-resistant Staphylococcus aureus (MRSA).33 McBryde et al. documented the spread of MRSA from patient clothing and patient beds to the gloved hands of HCWs. 34 Very rarely a HCW is a carrier,35 but here also, the infection spreads on the hands of a HCW. Some nurseries now routinely screen for MRSA at admission and attempt to contain this organism with isolation of colonized infants. In an outbreak situation, neonates with MRSA should be placed in contact precautions, preferably in a separate room from the rest of the unit and with cohorting of staff, though this may not always be possible.

Resistant gram-negatives and viruses, such as RSV, are other important nosocomial pathogens.36 While some outbreaks of gram-negatives have been linked to contaminated antibiotics, total parenteral nutrition, or intravenous fluids, most are the result of poor infection-control techniques.37

Equipment routinely used should be thoroughly cleaned after use and whenever possible, each neonate should have his own dedicated equipment. The role of hand rubs is evolving in the NICU, but clearly is effective.38 Parents and staff should avoid the NICU when ill, especially with contagious diseases such as diarrhea, adenoviral conjunctivitis, and herpes simplex infections of the mouth or hands.

Breast milk is often used to feed infants in the nursery, including infants too ill to breastfeed directly. Infection-control policy should address clean methods of collecting, saving, and dispensing fresh and frozen milk to infants. Care should be taken that infants receive only their own mother's milk, or under the guidance of a milk bank, safely stored and screened donor milk.

Infection Control in the Pediatric Intensive Care Unit

After the NICU, the Pediatric Intensive Care Unit (PICU) is the next most important site for nosocomial infections in the children's hospital. Here, as everywhere, hand hygiene and attention to infection-control practice is key for the prevention of nosocomial infections. Meticulous care in starting intravenous lines and following “bundling” recommendations (chlorhexidene skin preparation, full-barrier measures, and meticulous hand hygiene) are crucial.15 Infection-control issues should be considered for each child at admission to the PICU, and appropriate empiric isolation precautions started.

Each infection control program selects specific infections to monitor as part of hospital surveillance. Catheter-related bloodstream, cerebrospinal fluid and urinary tract infections should be actively monitored in real time to identify outbreaks promptly, especially in the ICU. Catheters should be removed as soon as possible. Catheter-related bloodstream infections are most deadly, especially in the burn unit,39 septic thrombophlebitis in particular. This life-threatening infection requires prompt recognition and surgical debridement of the vein.

When a multidrug-resistant organism is cultured from a patient in the ICU, a decision about whether to isolate the patient should be made. The more resistant the organism, the more concern about spread of the organism within the ICU. Contact precautions can be used to try to contain the organism. If multiple children are colonized, cohorting will likely be necessary as well.

Ventilator-associated pneumonia is very rare in pediatrics, while nosocomial transmission of respiratory viruses and rotavirus is a more common occurrence. Transmission-based precautions and strict attention to hand hygiene are critical to prevention.

Infection-control programs should maintain surveillance programs to be able to identify outbreaks. Surveillance should reflect particular populations and their specific risks for outbreaks. The program should develop and implement policies to improve safety in the hospital.40

Special Situations: Construction

Construction, remodeling, and new additions to a health care facility all carry infection risks that need to be managed and minimized. Infection-control guidelines should be followed in all hospital construction planning and execution. Ceilings, elevator shafts, and insulation have also been found to contain the fungal conidia of Aspergillus, a special concern in immunocompromised patients; and they should be removed from areas adjacent to construction,41 with barriers placed to separate air supply from hospital units.

The hospital water supply is vulnerable to contamination, especially with Legionella species.42 Immunocompromised and transplant patients are especially susceptible. The route of infection is usually via inhalation of contaminated aerosols from environmental sources, including hot water supplied in hospitals. The use of routine surveillance cultures of the water supply is not recommended, but should be used in outbreak situations to identify possible sources.

Disaster Preparedness

Disaster preparedness is an essential role of the infection-control program. Disasters, which include both natural pandemics and acts of biological terrorism, stress the resources and personnel of any health care system. The infection-control program should work with the community to be part of preparedness drills and HCW educational programs. Ideally, personal protective equipment is available and HCWs are trained to use these appropriately. Medications for particular threats may be difficult to stockpile, and should be available from a federal source in the case of a biological attack.43

Children are especially vulnerable to disasters and the aftermath. Children with more rapid respiratory rates and increased body/surface areas are at increased risk of exposure and disease, after a toxin or biological weapon attack. Increased body/surface area also makes hypothermia and exposure more serious than for the adult, including during a decontamination procedure. The pediatric population requires different doses of antibiotics and antidote compounds than adult victims, and in an emergency, this information should be readily available. Thus, careful planning and training for possible disasters is essential in maximizing the quality of disaster care children receive in your hospital and local community.44

The recently held Pediatric Preparedness for Disasters and Terrorism: A National Consensus Conference focused on eight major areas to improve preparedness for disasters like pandemics and terrorism, as well as natural disasters. These areas include emergency and prehospital care, hospital care, emergency preparedness, terrorism preparedness, mental health needs, school preparedness, training and drills, and future research and funding (CDC website: www.CDC.gov).