Treating Parents Colonized With Staph Aureus Cuts NICU Transmission Risk

Staphylococcus aureus infections are serious health care-associated infections and are especially dangerous when they occur in the neonatal intensive care unit (NICU).

Prevention strategies in the NICU primarily focus on limiting neonatal exposure to S aureus via reservoirs in the environment and health care workers, but the role of parents as a reservoir has not been not well studied.

With this in mind, a team led by investigators from Johns Hopkins set out to evaluate whether treating parents colonized with S aureus could reduce transmission from parent to neonates.

The results of the double-blinded randomized clinical trial were published in JAMA.

The study was conducted in 2 tertiary NICUs in Baltimore, Maryland, from November 7, 2014, through December 13, 2018. In total, the study enrolled 236 neonates with parents colonized with S aureus.

The primary end point of the study was neonatal acquisition of the same S aureus strain as their parent at time of screening within 90 days. Secondary outcomes included neonatal acquisition of any strain of S aureus and neonatal S aureus infections.

For the investigation, 117 parents were assigned to receive intranasal mupirocin and 2% chlorhexidine—impregnated cloths while 119 parents were placed in the placebo group and received petrolatum intranasal ointment and nonmedicated soap cloths. Both groups received 5 days of treatment.

In total, 208 neonates were included in the analytic sample, 18 of whom were lost to follow up. Available information indicates that 55% of the neonates were male, 76% were from a singleton birth, the mean birthweight was 1985 grams, and 76% of infants were born via vaginal births.

Of the 190 neonates in the analysis, 74 (38.9%) acquired S aureus colonization within 90 days. From this population, 42 (56.8%) had a strain concordant with the baseline parental strain.

The investigators observed that in the intervention and placebo groups, 13 of 89 neonates (14.6%) and 29 of 101 neonates (28.7%), respectively, acquired concordant S aureus colonization (risk difference, —14.1% [95% CI, –30.8% to –3.9%]; hazard ratio [HR], 0.43 [95.2% CI, 0.16 to 0.79]).

In looking at secondary outcomes, 28 of 89 neonates (31.4%) in the intervention group and 46 of 101 neonates (45.5%) in the control group acquired any S aureus strain (HR, 0.57 [95% CI, 0.31 to 0.88]), and 1 neonate (1.1%) in the intervention group and 1 neonate (1.0%) in the control group developed an S aureus infection prior to colonization. The investigators also note that skin reactions in parents were common in both groups (4.8% intervention, 6.2% placebo).

Based on these findings, the study investigators report that treating parents colonized with S aureus with intranasal mupirocin and chlorhexidine-impregnated cloths significantly reduced neonatal colonization with concordant S aureus strains when compared with placebo. However, the investigators caution that more work is needed.

“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,” the authors concluded.