Decolonizing Parents Cuts NICU Staph Transmission Risk

Nicola M. Parry, DVM

January 13, 2020

Treating colonized parents of neonates hospitalized in the neonatal intensive care unit (NICU) may reduce the risk of parents spreading Staphylococcus aureus to the infants, a recent study published online December 30 in JAMA has shown.

"Treating parents of neonates in the NICU with intranasal mupirocin and 2% chlorhexidine-impregnated cloths compared with placebo reduced the risk of a neonate acquiring S aureus colonization with strains that were the same as S aureus strains identified from the parent(s) at time of study enrollment," write Aaron M. Milstone, MD, MHS, from Johns Hopkins University, Baltimore, Maryland, and colleagues.

"In this trial, more than half of neonates who acquired S aureus had the same strain as their parent(s)."

According to the authors, neonates have an immature microbiome at the time of their admission to the NICU and rarely are already colonized by S aureus. Instead, they become colonized in the NICU after exposure to the organism from colonized or infected people and contaminated objects in the environment.

Staphylococcus aureus remains a common cause of outbreaks and healthcare-associated infections in NICUs and can seriously impact affected infants, with long-term sequelae such as poor neurodevelopmental and growth outcomes.

Although infection prevention strategies in NICUs typically center on healthcare workers and the physical environment as reservoirs for exposure of infants to S aureus, parents may also serve as an important reservoir for transmission of the bacterium.

With this in mind, Milstone and colleagues conducted their double-blinded, randomized controlled trial across two tertiary care NICUs to investigate whether treating parents would reduce the risk of their infants becoming colonized with S aureus.

The Treating Parents to Reduce Neonatal Transmission of Staphylococcus aureus (TREAT PARENTS) trial enrolled 236 infants. It included infants who had not had a previous culture positive for S aureus, had at least a 5-day NICU stay, were no more than 7 days old if admitted to the NICU from an outside location, and had at least one parent who tested positive for S aureus at screening.

The study's primary endpoint was infants' acquisition within 90 days of the same S aureus strain that their parent had. Secondary outcomes included infants' acquisition of any strain of S aureus and neonatal S aureus infections.

Parents in the study received 5 days of treatment. They were randomly assigned to intranasal mupirocin and topical bathing with 2% chlorhexidine-impregnated cloths (n = 117) or placebo treatment with petrolatum intranasal ointment and nonmedicated soap cloths (n = 119).

Of the 236 enrolled infants, 208 (55% male; 76% singleton births; mean birthweight 1985 grams; 76% vaginal births) were included in the analytic sample, although 18 of these were lost to follow-up.

A total of 190 infants were included in the final analysis: 89 in the intervention group and 101 in the placebo group. Of these, 74 (38.9%) acquired S aureus colonization by 90 days, 42 (56.8%) of whom had a strain concordant with a parental baseline strain.

According to the researchers, fewer (n = 13; 14.6%) infants in the intervention group than in the placebo group (n = 29; 28.7%) acquired concordant S aureus colonization (risk difference, –14.1%; hazard ratio [HR], 0.43).

Similarly, fewer infants in the intervention group acquired any S aureus strain
(n = 28; 31.4% vs n = 46; 45.5%; HR, 0.57).

One infant (1.1%) in the intervention group and 1 (1.0%) in the placebo group developed a S aureus infection before colonization. Skin reactions in parents occurred commonly in both groups (4.8% vs 6.2%).

"This trial suggests that parents are a major reservoir from which neonates acquire S aureus in the NICU," the authors write.

"Treating colonized parents may reduce risk of S aureus transmission to neonates, but these findings are preliminary and require further research for replication and to assess generalizability."

This study "offers a novel and promising strategy to address a highly relevant, often intractable, clinical problem", and "provides an explanation why interventions that primarily target patients and health care workers can fail to eradicate MSSA [methicillin-susceptible S aureus] in the NICU," pediatric infectious disease specialists Philip Zachariah, MD, MSc, and Lisa Saiman, MD, MPH, write in an accompanying editorial.

However, they highlight some features of the study that indicate a need for further investigation before this strategy could be widely adopted by other NICUs. For example, both study NICUs already used active surveillance and decolonization protocols for both MSSA and MRSA, which limits generalizability of this treatment strategy.

In addition, the study was not powered to detect differences in infections or mortality, the editorialists say. Scalability is another concern, they add, noting that the study took 4 years to complete and that 92.7% of infants who were screened for eligibility failed to meet its inclusion criteria.

"Cost-effectiveness will also need to be determined," Zachariah and Saiman add. Zachariah is from Columbia University Irving Medical Center, New York City, and Saiman is from NewYork-Presbyterian Hospital in New York City.

Nevertheless, the editorialists conclude that regardless of whether future research will support integration of this strategy into routine care, "Milstone and colleagues have made an important advance into this difficult area with the promise of having a meaningful benefit on neonatal care."

This study was supported by the Agency for Healthcare Research and Quality. Three authors report receiving grants from the Centers for Disease Control and Prevention, the National Institutes of Health, Sage Products Inc, Singulex Inc, Curetis Inc, Accelerate Inc, and GenMark. The same three authors report personal fees from Becton Dickinson, Novartis, Theravance, Basilea, Pattern Diagnostics, and GenMark. The remaining authors and the editorialists have disclosed no relevant financial relationships.

JAMA. Published online December 30, 2019. Abstract, Editorial

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