Infection Spread in the NICU: “The Tip of the Iceberg” - Part 1

Late one summer at the Children’s Hospital of Philadelphia, a top American medical centre, routine microbiological surveillance revealed something unusual in the neonatal intensive care unit: Over four weeks, 23 newborns tested positive for adenovirus, though not a single NICU patient had been infected with the virus the entire previous year.

The outbreak was cause for alarm.

In healthy children, adenovirus particles — launched airborne by coughs and sneezes and hardy enough to survive for weeks on surfaces — cause little more than a sore throat or pink eye. But in ill newborns, the most fragile of patients, adenovirus can trigger dire respiratory complications. Indeed, among the infected babies in Philadelphia, 12 required extra breathing support and 5 developed pneumonia. Four babies died.

An intense investigation traced the outbreak to contaminated eye-exam instruments — lenses and scopes that, notably, had been touched only by providers. In other words, the investigators emphasized, adenovirus can be spread even by equipment “that does not directly contact patients.”

These days, concern about infection spread at hospitals largely revolves around Covid-19. But well before the emergence of SARS-CoV-2, containing dangerous pathogens was an urgent and complex battle for hospitals, particularly in the NICU.

The coronavirus pandemic has only increased the risks facing the smallest, most vulnerable patients. To protect hospitalized newborns and assuage their anxious parents, hospitals are bolstering their infection-control strategies, minimizing the number of healthcare staff and visitors allowed near NICU patients, augmenting hand-hygiene protocols, and deploying air dis-infection technology to eradicate pathogens in the NICU air.

“This is an exceptional time,” says Hany Aly, M.D, chair of neonatology at Cleveland Clinic, a prominent American hospital that has made numerous changes to its infection-control practices.

Airborne Pathogens: Nothing New in the NICU

Indeed, today’s circumstances are exceptional, but in reality, augmented infection-control practices in the NICU were warranted prior to the pandemic and will remain so when the Covid-19 crisis abates.

In developed countries worldwide, up to 25% or 30% of NICU patients may contract an infection, whether viral, bacterial, or fungal. Developing countries bear a much higher burden.

NICUs account for 18% of all hospital infection outbreaks recorded in the worldwide Outbreak Database, numbers that may represent “only the tip of the iceberg,” according to Jayashree Ramasethu, M.D., NICU director at MedStar Georgetown University Hospital in the United States.

Premature and ill infants are, of course, highly susceptible to infection, because of their immature immune systems and fragile skin and because the very devices they depend on for life, such as ventilators and catheters, are common channels for bacterial invasion.

What’s more, advances in neonatal care are increasing the NICU’s population of smaller and sicker infants, the patients most likely to develop and succumb to serious infection.

As Dr Ramasethu notes, infection spread in the NICU presents hospitals with a daunting trifecta: “serious consequences for patients, huge economic burdens and staffing issues.”

The average NICU infection outbreak strikes 24 patients, with a mortality rate of 6.4%, according to a German review of 276 NICU outbreaks. As for the financial burden, infections often add weeks to a newborn’s hospital stay while more than doubling the cost, as British research has shown.

Superbug Outbreaks in the NICU

Thus far, only a small number of infants have contracted Covid-19, primarily from their caregivers, and no cases of in-hospital transmission have been reported. Most infants who have contracted the disease have recovered without complication, though severe cases requiring mechanical ventilation have been reported, and clearly, the utmost precautions must be taken around infected babies.

Compared to adults, “neonates tend to have a milder infection based on the very limited number of cases published so far,” according to a peer-reviewed literature review.

However, the same cannot be said for the way newborns fare when infected by pathogens other than SARS-CoV-2. Among the dangerous microbes known to lurk in the NICU, the superbug MRSA may be the most concerning.

“Neonates are particularly vulnerable to colonization and infection with MRSA,” cautioned a research team at Yale University School of Medicine in the United States.

About 30% of MRSA-colonized babies will develop an invasive infection. Among the potentially dire consequences: sepsis, meningitis, necrotizing pneumonia, respiratory tract infection, and endocarditis.

MRSA outbreaks in NICUs have been reported worldwide — in Germany, Great Britain, Israel, Japan, Scotland, Taiwan, and elsewhere — and incidence of MRSA in the NICU is skyrocketing.

The Yale study, reviewing data from 149 NICUs, found MRSA infections increased by 308% over a decade. The emergence of multi-drug resistant MRSA strains, the authors warned, suggests “difficulties treating MRSA infections will only continue to escalate.”

Another study found MRSA infection in the NICU independently increased the newborns’ length of stay by 40 days and added, on average, over $164,000 in costs per patient.

MRSA droplets can hover in the air and can survive for weeks on floors, door handles, sinks, mops, nursing scrubs, and towels, allowing for easy transmission to newborns.

The bacteria is so easily spread that when a triplet, later discovered to have been colonized, was transferred from one Danish NICU to another, 32 newborns in the second NICU became colonized with the same rare MRSA strain. The index patient had become colonized during a 15-day stay in a room adjacent to an isolation room that had housed an MRSA-infected newborn.

Read part two here