Comparison of bacterial profiles in human milk from mothers of term and preterm infants

Abstract Background Reducing the disposal of donated human milk (HM) is important for efficient management of human milk banks (HMBs). The presence of bacteria growth is the main factor that contributes to the disposal of donated HM. The bacterial profile in HM is suspected to differ between term an...

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Main Authors: Kumiko Miura, Miori Tanaka, Midori Date, Mizuho Ito, Noriko Mizuno, Katsumi Mizuno
Format: Article
Language:English
Published: BMC 2023-06-01
Series:International Breastfeeding Journal
Subjects:
Online Access:https://doi.org/10.1186/s13006-023-00563-3
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author Kumiko Miura
Miori Tanaka
Midori Date
Mizuho Ito
Noriko Mizuno
Katsumi Mizuno
author_facet Kumiko Miura
Miori Tanaka
Midori Date
Mizuho Ito
Noriko Mizuno
Katsumi Mizuno
author_sort Kumiko Miura
collection DOAJ
description Abstract Background Reducing the disposal of donated human milk (HM) is important for efficient management of human milk banks (HMBs). The presence of bacteria growth is the main factor that contributes to the disposal of donated HM. The bacterial profile in HM is suspected to differ between term and preterm mothers, with HM from preterm mothers containing more bacteria. Thus, elucidation of the causes of bacterial growth in preterm and term HM may help to reduce the disposal of donated preterm HM. This study compared the bacterial profiles of HM between mothers of term infants and mothers of preterm infants. Methods This pilot study was conducted in the first Japanese HMB, which was initiated in 2017. This study analyzed 214 human milk samples (term: 75, preterm: 139) donated by 47 registered donors (term: 31, preterm: 16) from January to November 2021. Bacterial culture results in term and preterm HM were retrospectively reviewed in May 2022. Differences in total bacterial count and bacterial species count per batch were analyzed using the Mann–Whitney U test. Bacterial loads were analyzed using the Chi-square test or Fisher’s exact test. Results The disposal rate did not significantly differ between term and preterm groups (p = 0.77), but the total amount of disposal was greater in the preterm group (p < 0.01). Coagulase-negative Staphylococci, Staphylococcus aureus, and Pseudomonas fluorescens were frequently found in both types of HM. Serratia liquefaciens (p < 0.001) and two other bacteria were present in term HM; a total of five types of bacteria, including Enterococcus faecalis and Enterobacter aerogenes (p < 0.001) were present in preterm HM. The median (interquartile range) total bacterial counts were 3,930 (435–23,365) colony-forming units (CFU)/mL for term HM and 26,700 (4,050–334,650) CFU/mL for preterm HM (p < 0.001). Conclusions This study revealed that HM from preterm mothers had a higher total bacterial count and different types of bacteria than HM from term mothers. Additionally, preterm infants can receive nosocomial-infection-causing bacteria in the NICU through their mother’s milk. Enhanced hygiene instructions for preterm mothers may reduce the disposal of valuable preterm human milk, along with the risk of HM pathogen transmission to infants in NICUs.
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spelling doaj.art-70ff72fd0ec34625967c14f6fd9ad7182023-06-11T11:26:28ZengBMCInternational Breastfeeding Journal1746-43582023-06-011811810.1186/s13006-023-00563-3Comparison of bacterial profiles in human milk from mothers of term and preterm infantsKumiko Miura0Miori Tanaka1Midori Date2Mizuho Ito3Noriko Mizuno4Katsumi Mizuno5The Nippon Foundation Human Milk BankThe Nippon Foundation Human Milk BankThe Nippon Foundation Human Milk BankThe Nippon Foundation Human Milk BankJapan Human Milk Bank AssociationThe Nippon Foundation Human Milk BankAbstract Background Reducing the disposal of donated human milk (HM) is important for efficient management of human milk banks (HMBs). The presence of bacteria growth is the main factor that contributes to the disposal of donated HM. The bacterial profile in HM is suspected to differ between term and preterm mothers, with HM from preterm mothers containing more bacteria. Thus, elucidation of the causes of bacterial growth in preterm and term HM may help to reduce the disposal of donated preterm HM. This study compared the bacterial profiles of HM between mothers of term infants and mothers of preterm infants. Methods This pilot study was conducted in the first Japanese HMB, which was initiated in 2017. This study analyzed 214 human milk samples (term: 75, preterm: 139) donated by 47 registered donors (term: 31, preterm: 16) from January to November 2021. Bacterial culture results in term and preterm HM were retrospectively reviewed in May 2022. Differences in total bacterial count and bacterial species count per batch were analyzed using the Mann–Whitney U test. Bacterial loads were analyzed using the Chi-square test or Fisher’s exact test. Results The disposal rate did not significantly differ between term and preterm groups (p = 0.77), but the total amount of disposal was greater in the preterm group (p < 0.01). Coagulase-negative Staphylococci, Staphylococcus aureus, and Pseudomonas fluorescens were frequently found in both types of HM. Serratia liquefaciens (p < 0.001) and two other bacteria were present in term HM; a total of five types of bacteria, including Enterococcus faecalis and Enterobacter aerogenes (p < 0.001) were present in preterm HM. The median (interquartile range) total bacterial counts were 3,930 (435–23,365) colony-forming units (CFU)/mL for term HM and 26,700 (4,050–334,650) CFU/mL for preterm HM (p < 0.001). Conclusions This study revealed that HM from preterm mothers had a higher total bacterial count and different types of bacteria than HM from term mothers. Additionally, preterm infants can receive nosocomial-infection-causing bacteria in the NICU through their mother’s milk. Enhanced hygiene instructions for preterm mothers may reduce the disposal of valuable preterm human milk, along with the risk of HM pathogen transmission to infants in NICUs.https://doi.org/10.1186/s13006-023-00563-3Neonatal intensive care unitHuman milkDonor milkHuman milk microbiotaBacteriological test
spellingShingle Kumiko Miura
Miori Tanaka
Midori Date
Mizuho Ito
Noriko Mizuno
Katsumi Mizuno
Comparison of bacterial profiles in human milk from mothers of term and preterm infants
International Breastfeeding Journal
Neonatal intensive care unit
Human milk
Donor milk
Human milk microbiota
Bacteriological test
title Comparison of bacterial profiles in human milk from mothers of term and preterm infants
title_full Comparison of bacterial profiles in human milk from mothers of term and preterm infants
title_fullStr Comparison of bacterial profiles in human milk from mothers of term and preterm infants
title_full_unstemmed Comparison of bacterial profiles in human milk from mothers of term and preterm infants
title_short Comparison of bacterial profiles in human milk from mothers of term and preterm infants
title_sort comparison of bacterial profiles in human milk from mothers of term and preterm infants
topic Neonatal intensive care unit
Human milk
Donor milk
Human milk microbiota
Bacteriological test
url https://doi.org/10.1186/s13006-023-00563-3
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