INTRODUCTION:

Neonates represent a unique and highly vulnerable patient population. Advances in medical technology that have occurred over the last few decades have improved the survival and quality of life for neonates¹.But the neonatal patients are at risk for acquiring nosocomial infections due to the need for invasive monitoring and supportive care². The National Institute of Child Health and Human Development sponsored “Neonatal Network” indicated that 29% of infants born at 25 to 28 weeks gestation and 46% of infants born less than 25 weeks gestation experience a serious nosocomial infection during hospitalization in the NICU³. Although immunological immaturity and altered cutaneous barriers play some role in the vulnerability of neonates to nosocomial infections, clearly, therapeutic interventions that have proven to be life saving for these fragile infants also appears to be associated with the majority of infectious complications resulting in neonatal morbidity and mortality.¹

Definition

The US Department of Health and Human science centers for Disease Control and Preventive defines nosocomial infection as an infection during hospitalization that was not present or incubating at the time of admission.

Incidence

The neonatal intensive care unit (NICU) nosocomial infection rate has increased over the past decade.⁴ In the United States, more than 2,000,000 nosocomial infections (in infants and adults) occur each year.³

Nosocomial infection increase the costs of neonatal intensive care, prolonged hospitalization by several weeks , and are responsible for almost 50% of the deaths that occur beyond 2 weeks of age.

The total number of neonates who develop nosocomial infection per admission varies from 6.2 to 33%. The variability of the infection rates depends on the gestational age, distribution of the infants surveyed for the report, the specific environment and care practices.

Predisposing factors

1. Host- related

Premature and very low birth weight infants appear to be particularly vulnerable to nosocomial sepsis due to their relative immune deficiency.

Other factors associated with an increased risk of nosocomial infection include: Neutropenia associated with hypertensive mother, degree of prematurity, prolonged rupture of membranes and maternal disease or infection.

2. Clinical practice related

Clinical practice factors associated with an increased likelihood that the neonate has nosocomial fungal sepsis include: Need for mechanical ventilation, exposure to a central venous catheter, catheter hub manipulation, and prolonged exposure to total parentral nutrition or intravenous lipids and delayed enteral fluids.

3. Environmental factors

In the vast majority of the cases it has been found that the transmission is due to cross-contamination from health care workers.

Reservoirs for transmission are numerous: laundry, soap bottles and sink, hand lotion, blood gas analyzer, ventilator circuits, multi-use vials, sibling-to mother-to-patient, water tap, hands, suction equipment, air conditioner, wooden tongue depressor, expressed mother’s milk, powdered milk, latex gloves, and resuscitator.

Clinical presentation

The dominant presenting features of septicemia or sepsis include:

· Increasing apnea (55%)

· Feeding intolerance, abdominal distension or gram positive stools (43%)

· Need for increased respiratory support

· Lethargy and hypotonia (23%)

· Abnormal white blood cell count (46%)

· Unexplained metabolic acidosis (11%)/ Hyperglycemia (10%)

· Gram negative nosocomial sepsis often presents with a more rapid clinical deterioration and is commonly associated with shock and coagulation problems.

Diagnosis

The gold standard for the diagnosis of nosocomial sepsis remains the finding of a positive blood culture for a known pathogen. There are two common errors that are made in evaluating neonates with possible sepsis.

Type I error (false positive, contaminant)

A type I error (false positive, contaminant) is accepting a positive culture as real when the patient is not truly bacteremic. Type I errors lead to the overuse of antibiotics and can subsequently increase the risk for more serious infections.

The best way to avoid type I errors is to prevent coagulase negative staphylococci contamination of blood cultures. Preparing the skin prior to puncture requires broad spectrum site antisepsis, however, the skin of the neonate, especially the preterm neonate, is more susceptible to damage from antiseptic agents. Additionally, the thinner layer of epidermis in premature neonates also contributes to the enhanced absorption of disinfectants. Chlorhexidine glucorate and povidone-iodine appears to be the best, agents. A 30 second exposure time is recommended, followed by removal with sterile water/ saline.

Type II errors (false negative, inadequate culture)

This occur when a negative blood culture result is accepted as proof that the patient is not infected when, in fact, the patient has true bacteremia that has not been detected by the blood culture. Consequently, type II error can lead to under treatment of neonates with life threatening sepsis.

The best way to reduce type II errors is to obtain adequate blood culture specimens.⁴

Impacts of nosocomial infection

Nosocomial infections are associated with significant morbidity and increased mortality.

· Meningitis may result in multiple major impairment, seizure disorder, cerebral palsy, learning disabilities and mental retardation.

· Ventilator associated pneumonia predisposes the infant to chronic lung changes.

· Systemic infection presenting with tissue perfusion, profound acidosis and end organ failure can lead to death.

Prevention

A multidisciplinary team approach to care for infants in the NICU potentially can provide a partnering strategies and practices to decrease nosocomial infections.

1. A team commitment to early extubation decreases the number of days.

2. A team commitment to an early feeding protocol increases the number of infants who are susceptible to changes in the intestinal mucosa that increases the risk of necrotizing enterocolitis.

3. Early feeding also decreases the nutrition and central venous lines by shortening the duration of time it takes to advanced feeding.

4. A team commitment to decreasing the number of skin puncture an infant receives can decrease the number of entry sites for pathogens.

5. Hand hygiene has been singled out as the most important measure in preventing hospital acquired infection.

Hand hygiene:

Washing before touching a patient is an immediate safety concern for that patient, washing afterwards may protect the caregiver and exposed to their future contacts.

Table2: Potential better Practices for Preventing Nosocomial Infection

Handwashing:

· Meticulous attention to hand washing, with regular monitoring and surveillance of hand washing practice and reporting of compliance.

Nutrition

· No alteration of hyper alimentation solutions after preparation

· Initiation of enteral feedings as early as possible

· Reduced exposure to intravenous lipids and hyper alimentation.

· Promotion of the use of human milk, ensuring proper collection and storage.

Skin care

· Initiation of skincare protocol for all neonates weighing<1000gm, the goals of which are to promote skin maturation and to prevent skin breakdown.

· Reduced laboratory testing that require venipuncture or heel stick.

· Development of a systematic approach to intravenous therapy that reduces the frequency and number of skin punctures for placement of

an intravenous catheter.

Diagnosis

· Establishment of a minimum sample size for a blood culture that is 1 ml/ aerobic culture bottle.

· Preference for two samples of 1ml each in two aerobic culture bottles

· Development of a method distinguishes true infection from a contaminated culture.

Respiratory care

· Minimization of intubation days

· Minimization of the interruption of the ventilator-endotracheal tube circuit

Vascular access

· Minimization of the use of central lines, and when used, minimization of the frequency of daily entries and the duration of use.

· Prospective placement of central lines when intravenous therapy will be of long duration.

· Establishment of sound policies and procedures for line care and access and regular monitoring of compliance.

Unit culture

· Promotion of developmentally supportive care, with an emphasis on minimal handling

· Development and maintenance of a culture of cooperation and team work that supports and encourages all team members to feel

responsible for outcomes.³