High Genetic Diversity Among Bacillus cereus Isolates Contaminating Donated Milk at a Canadian Human Milk Bank
department or school: Medicine, Faculty of
department or school: Non UBC
department or school: Obstetrics and Gynaecology, Department of
department or school: Pathology and Laboratory Medicine, Department of
data provider: DSpace
identifier citation: Microorganisms 13 (5): 1136 (2025)
contributor: Children's Hospital (Vancouver, B.C.). Research Institute
contributor: Children's Hospital (Vancouver, B.C.)
creator: Gene, Mathew
creator: Guthrie, Jennifer L.
creator: Li, Kevin
creator: Teatero, Sarah
creator: Paterson, Aimee
creator: Li, Angel
creator: Doyen, Alain
creator: Yamamura, Deborah
creator: Khan, Sarah
creator: Srigley, Jocelyn A.
creator: Stone, Debbie
creator: O’Connor, Deborah L.
creator: Poutanen, Susan
creator: Unger, Sharon
creator: McGeer, Allison
creator: Fittipaldi, Nahuel
issued: 2025-06-02T15:53:10Z
issued: 2025-05-15
description: Bacillus cereus poses a persistent challenge for human milk banks (HMBs) due to its ability to survive Holder pasteurization (HoP; 62.5 °C for 30 min). To ensure neonatal safety, any milk found to be contaminated post-HoP must be discarded, which impacts milk supply and adds to the operational demands of HMBs. In this study, we analyzed 688 B. cereus isolates from human milk (pre- and post-HoP), as well as from patient and environmental sources, to investigate human milk contamination by B. cereus at a Canadian HMB. Despite the limited temporal and geographic scope of the collection, the isolates exhibited remarkable genomic diversity, comparable to global B. cereus collections. Phylogenetic analysis at the core genome level revealed no clear clustering by isolate source, suggesting multifactorial pathways of B. cereus contamination. Isolates surviving HoP displayed gene variants linked to sporulation and cell wall integrity, suggesting a potential basis for HoP tolerance. Our findings emphasize that while genomic analyses offer major valuable insights, they alone are insufficient to address the complexities of B. cereus contamination in HMBs. Addressing this challenge will require combining genomic tools with robust monitoring systems, improved human milk-handling protocols, and pasteurization strategies better-suited to countering B. cereus resilience.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/91248
note: Academic Editor: Grzegorz WegrzynReceived: 7 April 2025Revised: 2 May 2025Accepted: 10 May 2025Published: 15 May 2025Citation: Gene, M.; Guthrie, J.L.; Li,K.; Teatero, S.; Paterson, A.; Li, A.;Doyen, A.; Yamamura, D.; Khan, S.;Srigley, J.A.; et al. High GeneticDiversity Among Bacillus cereusIsolates Contaminating Donated Milkat a Canadian Human Milk Bank.Microorganisms 2025, 13, 1136.https://doi.org/10.3390/microorganisms13051136Copyright: © 2025 by the authors.Licensee MDPI, Basel, Switzerland.This article is an open access articledistributed under the terms andconditions of the Creative CommonsAttribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/).ArticleHigh Genetic Diversity Among Bacillus cereus IsolatesContaminating Donated Milk at a Canadian Human Milk BankMathew Gene 1,†, Jennifer L. Guthrie 2,3,†, Kevin Li 4 , Sarah Teatero 2, Aimee Paterson 5,‡, Angel Li 5,Alain Doyen 6 , Deborah Yamamura 7,8, Sarah Khan 9,10, Jocelyn A. Srigley 11,12,13 , Debbie Stone 5,14,Deborah L. O’Connor 15, Susan Poutanen 5,16 , Sharon Unger 14,17,18, Allison McGeer 5,16and Nahuel Fittipaldi 2,4,*1 Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada;mathew.gene@alumni.utoronto.ca2 Public Health Ontario, Toronto, ON M5G 1M1, Canada; jennifer.guthrie@uwo.ca (J.L.G.);sarah.teatero@oahpp.ca (S.T.)3 Department of Microbiology and Immunology, Western University, London, ON N6A 3K7, Canada4 GREMIP and CRIPA, Faculty of Veterinary Medicine, University of Montreal,St-Hyacinthe, QC J2S 2M2, Canada; kevin.li.2@umontreal.ca5 Sinai Health System, Toronto, ON M5G 1X5, Canada; aimee.paterson@auckland.ac.nz (A.P.);xinliu.angelli@sinaihealth.ca (A.L.); debbie.stone@sinaihealth.ca (D.S.); susan.poutanen@sinaihealth.ca (S.P.);allison.mcgeer@sinaihealth.ca (A.M.)6 Department of Food Sciences, Institute of Nutrition and Functional Foods (INAF) and Dairy Science andTechnology Research Center (STELA), Laval University, Quebec City, QC G1V 0A6, Cana…
has type: Article
is shown at: 10.14288/1.0449007
language: eng
peer review status: Reviewed
provider: Vancouver : University of British Columbia Library
publisher: Multidisciplinary Digital Publishing Institute
publisher DOI: 10.3390/microorganisms13051136
rights: CC BY 4.0
rights URI: https://creativecommons.org/licenses/by/4.0/
scholar level: Faculty
scholar level: Researcher
scholar level: Other
subject: Bacillus cereus
subject: human milk bank and hospital
subject: human milk
subject: holder pasteurization
subject: contamination routes
subject: genetic diversity
subject: whole-genome sequencing
subject: sporulation
subject: neonatal health
type: Text
identifier URI: http://hdl.handle.net/2429/91248