Cronobacter sakazakii Infections in Two Infants Linked to Powdered Infant Formula and Breast Pump Equipment - United States, 2021 and 2022

Abstract

Cronobacter sakazakii, a species of gram-negative bacteria belonging to the Enterobacteriaceae family, is known to cause severe and often fatal meningitis and sepsis in young infants. C. sakazakii is ubiquitous in the environment, and most reported infant cases have been attributed to contaminated powdered infant formula (powdered formula) or breast milk that was expressed using contaminated breast pump equipment (1-3). Previous investigations of cases and outbreaks have identified C. sakazakii in opened powdered formula, breast pump parts, environmental surfaces in the home, and, rarely, in unopened powdered formula and formula manufacturing facilities (2,4-6). This report describes two infants with C. sakazakii meningitis reported to CDC in September 2021 and February 2022. CDC used whole genome sequencing (WGS) analysis to link one case to contaminated opened powdered formula from the patient's home and the other to contaminated breast pump equipment. These cases highlight the importance of expanding awareness about C. sakazakii infections in infants, safe preparation and storage of powdered formula, proper cleaning and sanitizing of breast pump equipment, and using WGS as a tool for C. sakazakii investigations.

FIGURE

Maximum likelihood phylogeny from high quality single nucleotide polymorphism* analysis^†,§,¶ of Cronobacter sakazakii patient A and B isolates and environmental isolates — United States, 2021 and 2022 Abbreviations: CSF = cerebrospinal fluid; SNP = single nucleotide polymorphism; // = skip mark. *SNP distances guide genetic relatedness between strains. ^† Scale bar indicates the genomic distance of samples to right of skip mark. ^§ Values at branch nodes indicate bootstrapping from 100 iterations. C. sakazakii isolates from patients A and B, in addition to environmental samples, form three distinct clusters in a maximum likelihood phylogeny. ^¶ Skip mark indicates a truncation to capture the relationship between clusters.