Bacillus cereus and severe intestinal infections in preterm neonates: Putative role of pooled breast milk

Abstract

Bacillus cereus is an environmental pathogen whose spores resist the usual cleaning procedure applied by the food industry and hospitals. We reported a cluster of severe intestinal infections due to Bcereus in 2 very low birth weight neonates from a neonatal intensive care unit. Environmental sampling and bacteriological analysis of pooled breast milk (PBM) were performed. Practices for preparation and administration of milk were observed and additional laboratory experiments performed. Strains were typed using M13-polymerase chain reaction and their virulence tested using cellular and insect models. Bcereus strains were exclusively isolated from intestinal tracts and PBM. No environmental culture yielded any viable Bcereus. Although genotypically diverse, both clinical and food strains exhibited high virulence potency. These findings pointed out the pathogenic potency of Bcereus in neonates; the putative role of PBM as a reservoir for pathogenic Bcereus and the triggered effect ofadefective care procedure, which allowed the growth of bacteria in pasteurized PBM. Well described from dried formula, the presence of pathogenic Bcereus strains in PBM was not previously reported. Careful monitoring of conditions during collection, conservation, and administration of PBM should be implemented in high-risk populations such as premature neonates.