Some infections are acquired after admission to the nursery rather than from the mother in utero or intrapartum. For some infections (eg, group B streptococci, herpes simplex virus [HSV]) it may not be clear whether the source is maternal or the hospital environment.
Hospital-acquired (nosocomial) infection is primarily a problem for premature infants and for term infants with medical disorders requiring prolonged hospitalization. Healthy, term neonates have infection rates < 1%. For neonates in special care nurseries, the incidence increases as birth weight decreases. The most common nosocomial infections are central line-associated bloodstream infections (CLABSI) and hospital-acquired pneumonia Hospital-Acquired Pneumonia Hospital-acquired pneumonia (HAP) develops at least 48 hours after hospital admission. The most common pathogens are gram-negative bacilli and Staphylococcus aureus; antibiotic-resistant organisms... read more .
(See also Overview of Neonatal Infections Overview of Neonatal Infections Neonatal infection can be acquired In utero transplacentally or through ruptured membranes In the birth canal during delivery (intrapartum) From external sources after birth (postpartum) Common... read more .)
Etiology of Neonatal Hospital-Acquired Infection
In term neonates, the most frequent hospital-acquired infection is
Skin infection due to Staphylococcus aureus Staphylococcal Infections Staphylococci are gram-positive aerobic organisms. Staphylococcus aureus is the most pathogenic; it typically causes skin infections and sometimes pneumonia, endocarditis, and osteomyelitis... read more (both methicillin-sensitive and methicillin-resistant)
Although nursery personnel who are S. aureus nasal carriers are potential sources of infection, colonized neonates and mothers also may be reservoirs. The umbilical stump, nose, and groin are frequently colonized during the first few days of life. Often, infections do not manifest until the neonate is at home.
In very-low-birth-weight (VLBW; < 1500 g) infants, gram-positive organisms cause about 70% of infections, the majority being with coagulase-negative staphylococci. Gram-negative organisms, including Escherichia coli Escherichia coli Infections The gram-negative bacterium Escherichia coli is the most numerous aerobic commensal inhabitant of the large intestine. Certain strains cause diarrhea, and all can cause infection when they invade... read more , Klebsiella Klebsiella, Enterobacter, and Serratia Infections The gram-negative bacteria Klebsiella, Enterobacter, and Serratia are closely related normal intestinal flora that rarely cause disease in normal hosts. Diagnosis is by culture. Treatment is... read more , Pseudomonas Pseudomonas and Related Infections Pseudomonas aeruginosa and other members of this group of gram-negative bacilli are opportunistic pathogens that frequently cause hospital-acquired infections, particularly in ventilator patients... read more , Enterobacter Klebsiella, Enterobacter, and Serratia Infections The gram-negative bacteria Klebsiella, Enterobacter, and Serratia are closely related normal intestinal flora that rarely cause disease in normal hosts. Diagnosis is by culture. Treatment is... read more , and Serratia Klebsiella, Enterobacter, and Serratia Infections The gram-negative bacteria Klebsiella, Enterobacter, and Serratia are closely related normal intestinal flora that rarely cause disease in normal hosts. Diagnosis is by culture. Treatment is... read more , cause about 20%. Fungi (Candida albicans Candidiasis (Invasive) Candidiasis is infection by Candida species (most often C. albicans), manifested by mucocutaneous lesions, fungemia, and sometimes focal infection of multiple sites. Symptoms depend on the site... read more and C. parapsilosis) cause about 10%. Patterns of infection (and antibiotic resistance) vary among institutions and units and change with time. Intermittent “epidemics” sometimes occur as a particularly virulent organism colonizes a unit.
Infection is facilitated by the multiple invasive procedures VLBW infants undergo (eg, long-term arterial and venous catheterization, endotracheal intubation, continuous positive airway pressure, nasogastric tubes or nasojejunal feeding tubes). The longer the stay in special care nurseries and the more procedures done, the higher is the likelihood of infection.
Prevention of Neonatal Hospital-Acquired Infection
Measures to reduce S. aureus colonization
Prevention of colonization and infection in special care nurseries and neonatal intensive care units (ICUs)
Surveillance for infection
Using a topical antiseptic agent during routine bathing or skin preparation for sterile procedures can help reduce bacterial skin colonization in newborns. Chlorhexidine-based products are increasingly used for this purpose, but the U.S. Food and Drug Administration warns of risk of skin irritation and chemical burns in infants < 2 months of age. The American Academy of Pediatrics recommends dry umbilical cord care, but this practice may result in high rates of colonization with S. aureus, and epidemics have occurred in some hospitals. During disease outbreaks, application of triple dye to the cord area or bacitracin or mupirocin ointment to the cord, nares, and circumcision site reduces colonization. Routine cultures of personnel or of the environment are not recommended.
Special care nurseries and neonatal ICUs
Prevention of colonization and infection in special care nurseries requires provision of sufficient space and personnel. In intensive care, multipatient rooms should provide 120 square ft (about 11.2 square m)/infant and 8 ft (about 2.4 m) between incubators or warmers, edge-to-edge in each direction. A nurse:patient ratio of 1:1 to 1:2 is required. In intermediate care, multipatient rooms should provide 120 square ft (about 11.2 square m)/infant and 4 ft (about 1.2 m) between incubators or warmers, edge-to-edge in each direction. A nurse:patient ratio of 1:3 to 1:4 is required.
Proper techniques are required, particularly for placement and care of invasive devices and for meticulous cleaning and disinfection or sterilization of equipment. Active monitoring of adherence to techniques is essential. Formal evidence-based protocols for inserting and maintaining central catheters have significantly decreased the rate of central line-associated bloodstream infection.
Similarly, a group of procedures and protocols that reduce healthcare-associated pneumonia in the neonatal ICU have been identified; these include staff education and training, active surveillance for healthcare-associated pneumonia, raising the head of an intubated neonate's bed 30 to 45°, and providing comprehensive oral hygiene. Placing the neonate in a lateral position with the endotracheal tube horizontal with the ventilator circuit also may be helpful.
Other preventive measures include meticulous attention to hand hygiene. Cleansing with alcohol preparations is as effective as soap and water in decreasing bacterial colony counts on hands, but if hands are visibly soiled, they should first be washed with soap and water. Incubators provide limited protective isolation; the exteriors and interiors of the units rapidly become heavily contaminated, and personnel are likely to contaminate their hands and forearms. Universal blood and body fluid precautions add further protection.
Active surveillance for infection is done. In an epidemic, establishing a cohort of diseased or colonized infants and assigning them a separate nursing staff are useful. Continuing surveillance for 1 month after discharge is necessary to assess the adequacy of controls instituted to end an epidemic.
Prophylactic antimicrobial therapy is generally not effective, hastens development of resistant bacteria, and alters the balance of normal flora in the neonate. However, during a confirmed nursery epidemic, antibiotics against specific pathogens may be considered—eg, penicillin G for prophylaxis against group A streptococcal infection (see Table: Recommended Dosages of Selected Parenteral Antibiotics for Neonates Recommended Dosages of Selected Parenteral Antibiotics for Neonates In neonates, the extracellular fluid (ECF) constitutes up to 45% of total body weight, requiring relatively larger doses of certain antibiotics (eg, aminoglycosides) compared with adults. Lower... read more ).
Inactivated vaccines should be given according to the routine schedule (see Table: Recommended Immunization Schedule for Ages 0–6 Years Recommended Immunization Schedule for Ages 0–6 Years Vaccination follows a schedule recommended by the Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics, the American Academy of Family Physicians, and the American... read more ) to any infant who is in the hospital at that time. Live viral vaccines (eg, rotavirus vaccine) are not given until the time of discharge to prevent spread of vaccine virus in the hospital.
Nosocomial infection is primarily a problem for premature infants and for term infants with disorders requiring prolonged hospitalization.
The lower the birth weight, the higher the risk of infection, particularly in neonates with central catheters, endotracheal tubes, or both.
Meticulous technique for inserting and maintaining catheters, tubes, and devices is essential for prevention; formal protocols improve adherence.
Prophylactic antibiotics are not recommended except possibly during a confirmed nursery epidemic involving a specific pathogen.