Are Low Lactose Concentrations a Risk Factor for Staphylococcus aureus-Associated Mastitis? †
by
, , , ,
Grace C. McLoughlin
1,2,3,*
,
Stefano Cacciatore
4,
Anna O. Okunola
5,
Noor-Ul-Huda Ghori
1,
Heather J. Zar
6,
Donna T. Geddes
2,3,7 and
Mark P. Nicol
1 1
School of Biomedical Sciences, The University of Western Australia, Crawley, WA 6009, Australia
2
ABREAST Network, Perth, WA 6000, Australia
3
UWA Centre for Human Lactation Research and Translation, Crawley, WA 6009, Australia
4
International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town 7925, South Africa
5
Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DSI-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town 7505, South Africa
6
Department of Pediatrics and Child Health, Red Cross Memorial Children’s Hospital, Cape Town 7925, South Africa
7
School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
*
Author to whom correspondence should be addressed.
†
Presented at the Australian Breastfeeding + Lactation Research and Science Translation Conference (ABREAST Conference 2023), Perth, Australia, 10 November 2023.
Proceedings 2023, 93(1), 6; https://doi.org/10.3390/proceedings2023093006
Published: 19 December 2023
(This article belongs to the Proceedings of Australian Breastfeeding + Lactation Research and Science Translation Conference 2023)
Abstract
:Staphylococcus aureus is a bacterium found in the milk of up to 38% of healthy lactating mothers; however, S. aureus is isolated with increased frequency from colostrum and mastitis milk. Both of these milk types have lower lactose concentrations compared to mature milk from healthy lactating mothers, which may indicate that lactose has a role in determining whether S. aureus can survive in human milk. The aim of this study was (1) to investigate whether the presence of S. aureus in human milk is associated with the milk’s lactose concentration, and (2) to determine whether different lactose concentrations can affect the ability of S. aureus isolates to grow in vitro. Human milk samples were collected at 10 weeks postpartum from mothers participating in the Drakenstein Child Health Study (Cape Town, South Africa) and underwent NMR spectroscopy to determine their metabolome. A subset of these samples (n = 117) was cultured to isolate S. aureus. Milk samples with lactose concentrations of less than 166 mM were more likely to have S. aureus present, compared to samples with lactose concentrations of over 166 mM (p < 0.001). In vitro, the growth of S. aureus was negatively correlated with the lactose concentration of axenic culture. Lactose concentrations associated with human milk appear to have an inhibitory effect on the growth of S. aureus human milk isolates. Therefore, low-lactose human milk could potentially be a risk factor for increased S. aureus growth and the development of S. aureus-associated mastitis.
Author Contributions
Conceptualization, G.C.M., N.-U.-H.G. and M.P.N.; methodology, G.C.M., N.-U.-H.G., A.O.O., S.C., H.J.Z., D.T.G. and M.P.N.; software, G.C.M.; formal analysis, G.C.M., N.-U.-H.G., D.T.G. and M.P.N.; investigation, G.C.M., D.T.G. and M.P.N.; resources, H.J.Z. and M.P.N.; data curation, G.C.M., A.O.O. and S.C.; writing—original draft preparation, G.C.M.; writing—review and editing, G.C.M., N.-U.-H.G., D.T.G. and M.P.N.; supervision, N.-U.-H.G., D.T.G. and M.P.N.; funding acquisition, H.J.Z. and M.P.N. All authors have read and agreed to the published version of the manuscript.
Funding
This work was supported by the Bill and Melinda Gates Foundation (OPP1017641; OPP1017579), and the Australian National Health and Medical Research Council (APP1174455). G.M. is supported by the Sibyl and Wylie Gibbons Scholarship award from the Marshall Centre (The University of Western Australia). D.T.G. is supported by an unrestricted research grant from Medela AG (Switzerland), administered by The University of Western Australia. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
Institutional Review Board Statement
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Human Research Ethics Committee of the University of Western Australia (protocol code 2019/RA/5/15/1294 and date of approval 27 May 2020).
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
Data sharing is not applicable.
Conflicts of Interest
D.T.G. declares participation in the Scientific Advisory Board of Medela AG. D.T.G. is supported by an unrestricted research grant from Medela AG, administered by The University of Western Australia. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. All other authors declare no conflict of interest.
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© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
MDPI and ACS Style
McLoughlin, G.C.; Cacciatore, S.; Okunola, A.O.; Ghori, N.-U.-H.; Zar, H.J.; Geddes, D.T.; Nicol, M.P. Are Low Lactose Concentrations a Risk Factor for Staphylococcus aureus-Associated Mastitis? Proceedings 2023, 93, 6. https://doi.org/10.3390/proceedings2023093006
AMA Style
McLoughlin GC, Cacciatore S, Okunola AO, Ghori N-U-H, Zar HJ, Geddes DT, Nicol MP. Are Low Lactose Concentrations a Risk Factor for Staphylococcus aureus-Associated Mastitis? Proceedings. 2023; 93(1):6. https://doi.org/10.3390/proceedings2023093006
Chicago/Turabian StyleMcLoughlin, Grace C., Stefano Cacciatore, Anna O. Okunola, Noor-Ul-Huda Ghori, Heather J. Zar, Donna T. Geddes, and Mark P. Nicol. 2023. "Are Low Lactose Concentrations a Risk Factor for Staphylococcus aureus-Associated Mastitis?" Proceedings 93, no. 1: 6. https://doi.org/10.3390/proceedings2023093006
