Developing global guidance on human milk banking

International expert meeting on the donation and use of human milk: Brief report

Where a mother's own milk is not available or is insufficient, donor human milk (DHM) processed by a human milk bank (HMB) is the recommended next best alternative. HMBs exist in over 65 countries. However, most countries have yet to establish national policies or programmes that support the provision of DHM. In July 2019, a group of international experts in fields relevant to human milk banking gathered at a meeting organised by the Institute of Biomedical Ethics, University of Zurich, and co-sponsored by the World Health Organisation. Prompted by the growing interest globally in creating and sustaining HMBs and addressing current safety and ethical concerns and standards, the aims of the meeting were to define knowledge gaps, determine the need for and scope of global guidelines and provide recommendations on steps that need to be taken at the international level. Following wide-ranging discussions that included the integration of milk banks into health care systems, strategy and policy, quality and safety, the use of DHM and associated ethical considerations, the overall conclusion of the meeting was that in the absence of global recommendations on the implementation, operation and regulation of HMBs, evidence-based guidance is urgently needed.

The global status of human milk banking

Human milk provides essential nutrition for infants and holds many health benefits for infants and mothers. When a mother's own milk is not available for her infant, the World Health Organization recommends feeding donor human milk (DHM) from a human milk banking facility. DHM is human milk produced, collected then donated to a human milk bank (HMB). HMBs serve many vital functions, including screening donor mothers, then collecting, processing, storing, and allocating DHM to recipients. The first HMB opened in 1909, and today there are more than 700 HMBs globally. Unfortunately, HMB facilities are not present in all locales, with notable gaps in South Asia and Africa. Additionally, there are no global standards to guide HMB operational procedures. Even though most HMBs attempt to employ quality control systems to provide safe DHM, differences in community needs, resource availability, and a range of methods and policies to execute processes result in significant variations in DHM quality and HMB operations. Robust and collaborative systems that ensure safe and equitable access to DHM are needed. In this paper, we present a global snapshot of current human milk banking practices; review an interdisciplinary framework to guide and support HMB activities as an integrated part of health and newborn care systems; discuss factors that contribute to HMB sustainability; outline barriers to scaling HMBs worldwide; and highlight knowledge, policy, and research gaps. Developing global HMB guidance and rigorous, adaptable standards would strengthen efforts to improve newborn health.

Review of current best practices for human milk banking

Mother's/parent milk is the optimal way to feed infants and when unavailable, supplemental donor human milk is preferred. A safe supply of donor human milk should be available for all low birthweight infants for whom it has been shown to reduce morbidity. Human milk banking has been in existence for more than a century, although largely shut down during the 1980s, primarily due to fears of human immunodeficiency virus transmission. With renewed security in milk banking, has come an exponential growth in human donor milk use. Guidelines for milk banking have been published in many countries including Australia, France, India, Italy, Spain, Switzerland, the United Kingdom and the nonprofit organization PATH. The European Milk Bank Association and the Human Milk Banking Association of North America have also published recommendations for milk banks throughout Europe and North America, respectively. Although there is variability among these guidelines, there is general consensus on quality control measures required to provide a supply of safe donor milk. These measures include effective donor screening, safe collection, transport and storage of milk, standardized pasteurization and bacteriological testing. Operational considerations are also critical, such as appropriate training for staff, equipment maintenance and cleaning, protocol and record keeping and inspection and accreditation. Clearly delineating these key quality control measures provides an excellent foundation for establishing international guidelines. Acceptable modifications must be established for low- and middle-income countries that do not have sufficient resources; overly burdensome guidelines may make establishing a milk bank unnecessarily prohibitive. This review presents a summary of current best practices for human milk banking.

Human Milk-The Biofluid That Nourishes Infants from the First Day of Life

Human milk is a biofluid with a unique composition among mammalian milks. Besides this milk's major components, its bioactive compounds, like hormones, immune factors, and oligosaccharides, are unique and important for infant growth and development. The best form of nutrition for term and preterm infants is the mother's own milk. However, in the absence of the mother's own milk, donor milk should be made available. Milk banks support neonatal intensive care units by providing preterm infants with human milk that generally has reasonable nutritive value for this sensitive population. However, neither mother's own milk nor donor milk has sufficient energy content for the growth of preterm babies, so adequate human milk supplementation is crucial for their progress. Due to the different characteristics of human breast milk, as well as ubiquitous environmental pollutants, such as microplastics, new methods are required for monitoring the quality and characteristics of human milk, which will lay a solid foundation for the further development and progress of human milk research.

A systematic review of contaminants in donor human milk

Donor human milk (DHM) from a milk bank is the recommended feeding method for preterm infants when the mother's own milk (MOM) is not available. Despite this recommendation, information on the possible contamination of donor human milk and its impact on infant health outcomes is poorly characterised. The aim of this systematic review is to assess contaminants present in DHM samples that preterm and critically ill infants consume. The data sources used include PubMed, EMBASE, CINAHL and Web of Science. A search of the data sources targeting DHM and its potential contaminants yielded 426 publications. Two reviewers (S. T. and D. L.) conducted title/abstract screening through Covidence software, and predetermined inclusion/exclusion criteria yielded 26 manuscripts. Contaminant types (bacterial, chemical, fungal, viral) and study details (e.g., type of bacteria identified, study setting) were extracted from each included study during full-text review. Primary contaminants in donor human milk included bacterial species and environmental pollutants. We found that bacterial contaminants were identified in 100% of the papers in which bacterial contamination was sought (16 papers) and 61.5% of the full data set (26 papers), with the most frequently identified genera being Staphylococcus (e.g., Staphylococcus aureus and coagulase-negative Staphylococcus) and Bacillus (e.g., Bacillus cereus). Chemical pollutants were discovered in 100% of the papers in which chemical contamination was sought (eight papers) and 30.8% of the full data set (26 papers). The most frequently identified chemical pollutants included perfluoroalkyl substances (six papers), toxic metal (one paper) and caffeine (one paper). Viral and fungal contamination were identified in one paper each. Our results highlight the importance of establishing standardisation in assessing DHM contamination and future studies are needed to clarify the impact of DHM contaminants on health outcomes.

Unlocking the Potential: A Systematic Literature Review on the Impact of Donor Human Milk on Infant Health Outcomes

Human mother milk is considered the most healthy and best source of nutrition for both premature and full-term infants, as it possesses many health benefits and is associated with its consumption. Some of the mothers are not able to produce an adequate quantity of milk to meet the required needs of the infants, particularly in cases involving premature births or facing challenges in breastfeeding. Especially for the most vulnerable premature infants, donor human milk (DHM) provides a helpful bridge for effective breastfeeding. Even with the advancement in baby formulas, no other dietary source can match the bioactive matrix of benefits found in human breast milk. This literature review discusses the risks associated with prematurity and explores the use of DHM in the care of premature infants. It helps prevent substantial preterm complications, especially necrotizing enterocolitis, bronchopulmonary dysplasia, and late-onset sepsis, which are more commonly seen in infants who are given formulated milk made from cow's milk. It gives insights into the benefits of DHM, such as immunological and nutritional benefits, which is a basic infant's need. When medical distress prevents mothers from producing enough breast milk for their infants, pasteurized human donor breast milk should be made accessible as an alternative feeding option to ensure infants remain healthy and nourished. A systematic literature search was conducted using PubMed and Google Scholar databases and other sources. A total of 104 articles were searched, of which 35 were included after identification, filters were applied, eligibility was checked, and references out of scope were excluded. Human milk banking should be incorporated into programs encouraging breastfeeding, highlighting lactation in mothers and only using DHM when required.

Factors associated with informal human milk sharing among donors and recipients: A mixed-methods systematic review

BACKGROUND

The multiple benefits associated with the provision of human milk exceed individual health outcomes, engendering substantial economic, societal and environmental domains. Human milk is the absolute, unparalleled source of nutrition for infants. Informal human milk sharing is a modernistic and rapidly progressing practice. No systematic review of the factors associated with this contemporary practice among donors and recipients of informal human milk sharing exists.

AIM

The aim of this review was to identify, evaluate, synthesize and integrate the evidence on the factors associated with informal human milk sharing among donors and recipients.

METHODS

A mixed methods systematic review was conducted according to the Joanna Briggs Institute methodological guidance utilizing a convergent integrated approach. The following databases were systematically searched: CINAHL, Scopus, Medline and Embase and Web of Science between inception to August 2023. A grey literature search was conducted using multiple techniques. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Twenty-four studies were included in this review. Ten integrated findings relating to the factors associated with informal human milk sharing among donors and recipients were identified. The four integrated findings pertaining to donors included: altruistic motivation and value, resistance to commercialization and overcoming inaccessibility, uniting digital and personal connectedness and lack of awareness and acceptance of informal human milk sharing in healthcare settings. The six integrated findings relating to recipients included: maternal or infant factors, superiority and advantageous impact of breastmilk, human milk bank influences, digital connections and transparency, healthcare professional facilitation of informal human milk sharing, and professional and logistical implications.

CONCLUSION

This review highlighted a multitude of factors that motivate, facilitate and impede the practice of informal human milk sharing. Future research is required to explore these factors further within broader geographical locations to enhance the generalizability and rigor of the body of knowledge. Further studies should consider the exploration of the experiences and psychological impact of informal human milk sharing on donors and recipients. The provision of human milk to all infants is an imperative public health endeavor and thus positioning this as a key benchmark for research and practice is crucial.

Monitoring the Use of Human Milk, the Ideal Food for Very Low-Birth-Weight Infants-A Narrative Review

Aware of the utmost importance of feeding premature babies-especially those of lower weight-with human milk, as well as the need to monitor this important element of neonatal care, we focused on four aspects in this review. First of all, we reviewed the beneficial effects of feeding premature infants with breast milk in the short and long term. Secondly, we performed a quantitative evaluation of the rates of breastfeeding and feeding with human milk in Very-Low-Birth-Weight infants (VLBWs) during hospitalization in the Neonatal Intensive Care Unit (NICU) and at discharge. Our aim was to take a snapshot of the current status of human milk-feeding care and track its trends over time. Then we analyzed, on the one hand, factors that have been proven to facilitate the use of maternal milk and, on the other hand, the risk factors of not feeding with breast milk. We also considered the spread of human milk banking so as to assess the availability of donated milk for the most vulnerable category of premature babies. Finally, we proposed a protocol designed as a tool for the systematic monitoring of actions that could be planned and implemented in NICUs in order to achieve the goal of feeding even more VLBWs with human milk.

Setting up the first human milk bank in Uganda: a success story from Nsambya hospital

Background

The World Health Organization (WHO) strongly recommends the use of donor human milk (DHM) for low birth weight infants when mother's own milk is unavailable or insufficient. However, the use of DHM requires the availability of human milk banks (HMBs), the majority of which are in middle and high-income countries. Developing countries offer multiple opportunities and challenges regarding the establishment and operationalization of HMBs. This study describes the experience in setting up the HMB in Uganda at St. Francis Hospital Nsambya.

Methods

The establishment of the first HMB in Uganda followed a step-wise approach using the PATH's Resource Toolkit for Establishing and Integrating Human Milk Banks. The steps included: performing a facility readiness assessment, implementing quality control measures, forming and training a committee for the Baby Friendly Hospital Initiative, establishing a monitoring and evaluation system, developing a communication strategy, engaging with the Ministry of Health, providing staff training by a Human Milk Bank consultant, and maintaining regular coordination by a dedicated technical team.

Results

A total of 170 donors have been screened and of these 140 have donated milk with a mean age of 26 years since the establishment of the bank in November 2021. A total of 108 admitted neonates have received the milk; majority (88%) are preterm infants with a mean gestational age of 34 weeks. A total of 90 liters have been collected and 76 distributed. The challenges in establishment of the Human Milk bank included: lack of guidelines on human milk banking, use of unpasteurized milk, lack of communication strategy, lack of clear model infrastructure and lactation training. We addressed the challenges: by drafting guidelines, set up a human milk bank and had training on use donor pasteurized milk, designed communication messages through videos and brochures, visited Pumwani hospital and remodeled the Human Milk Bank according to the model at Pumwani, all the health workers in the human milk bank had a training on Lactation. Assessing the experiences and attitudes of mothers, donors, healthcare providers, and hospital leaders revealed concerns about milk safety and fear about potential attachments or acquired traits through the donated milk to the babies that may receive it. Donors viewed milk donation as a life-saving act, although fears of breast cancer and lumps arose from misconceptions. To address these perspectives, creative media, such as videos and messages, were designed to raise awareness, promote behavioral change, and create demand for the HMB services.

Conclusion

The establishment and integration of HMB services at hospitals in Uganda is feasible.

Potential effectiveness of integrating human milk banking and lactation support on neonatal outcomes at Pumwani Maternity Hospital, Kenya

We assessed the potential effectiveness of human milk banking and lactation support on provision of human milk to neonates admitted in the newborn unit (NBU) at Pumwani Maternity Hospital, Kenya. This pre-post intervention study collected data from mothers/caregivers and their vulnerable neonates or term babies who lacked sufficient mother's milk for several reasons admitted in the NBU. The intervention included establishing a human milk bank and strengthening lactation support. Preintervention data were collected between 5 October 2018 and 11 November 2018, whereas postintervention data were collected between 4 September 2019 and 6 October 2019. Propensity score-matched analysis was performed to assess the effect of the intervention on exclusive use of human milk, use of human milk as the first feed, feeding intolerance and duration of NBU stay. The surveys included 123 and 116 newborns at preintervention and postintervention, respectively, with 160 newborns (80 in each group) being included in propensity score matched analysis. The proportion of neonates who exclusively used human milk during NBU stay increased from 41.3% preintervention to 63.8% postintervention (adjusted odds ratio [OR]: 2.68; 95% confidence interval [CI]: 1.31, 5.53) and those whose first feed was human milk increased from 55.0% preintervention to 83.3% postintervention (adjusted OR: 5.09; 95% CI: 2.18, 11.88). The mean duration of NBU stay was 27% (95% CI: 5.8%, 44.0%) lower in the postintervention group than in the preintervention group. The intervention did not affect feeding intolerance. Integrating human milk banking and lactation support may improve exclusive use of human milk among vulnerable neonates in a resource limited setting.

Comparison between the for-profit human milk industry and nonprofit human milk banking: Time for regulation?

Human milk (HM) is a highly evolutionary selected, complex biofluid, which provides tailored nutrition, immune system support and developmental cues that are unique to each maternal-infant dyad. In the absence of maternal milk, the World Health Organisation recommends vulnerable infants should be fed with screened donor HM (DHM) from a HM bank (HMB) ideally embedded in local or regional lactation support services. However, demand for HM products has arisen from an increasing awareness of the developmental and health impacts of the early introduction of formula and a lack of prioritisation into government-funded and nonprofit milk banking and innovation. This survey of global nonprofit milk bank leaders aimed to outline the trends, commonalities and differences between nonprofit and for-profit HM banking, examine strategies regarding the marketing and placement of products to hospital and public customers and outline the key social, ethical and human rights concerns. The survey captured information from 59 milk bank leaders in 30 countries from every populated continent. In total, five companies are currently trading HM products with several early-stage private milk companies (PMCs). Products tended to be more expensive from PMC than HMB, milk providers were financially remunerated and lactation support for milk providers and recipients was not a core function of PMCs. Current regulatory frameworks for HM vary widely, with the majority of countries lacking any framework, and most others placing HM within food legislation, which does not include the support and care of milk donors and recipient prioritisation. Regulation as a Medical Product of Human Origin was only in place to prevent the sale of HM in four countries; export and import of HM was banned in two countries. This paper discusses the safety and ethical concerns raised by the commodification of HM and the opportunities policymakers have globally and country-level to limit the potential for exploitation and the undermining of breastfeeding.

A descriptive analysis of human milk dispensed by the Leipzig Donor Human Milk Bank for neonates between 2012 and 2019

Background

Human milk banking has become an important aspect of Nutritional medicine. It is not just about the provision of mother's own milk (MOM) or donor human milk (DHM) in the hospital, but also a strategy to encourage breastfeeding in the clinical setting and beyond.

Objective

To describe the feeding patterns of hospitalised infants including human milk dispensed by the Leipzig Donor Human Milk Bank (LMB).

Design

A descriptive analysis of daily data on milk feeds dispensed by LMB for hospitalised infants distinguishing between MOM or DHM, either fresh or frozen, and raw/pasteurised milk from 2012-2019.

Results

We included 2,562 infants with median hospitalisation of 23 days, for whom human milk was dispensed on median 76% of those days and other nutrition on the remaining days. Raw MOM and raw DHM comprised 52% and 8% of the dispensed milk, respectively. Dispensing exclusive DHM instead of MOM for at least one full day was required for 55% of the infants, mostly at the beginning but also later during hospitalisation. Exclusive raw DHM was dispensed on at least 1 day for 37% of the infants, in different birthweight strata <1,000 g: 10%, 1,000-1500 g: 11%, 1,500-2500 g: 13% and > 2,500 g: 3%. At discharge, MOM was dispensed for more than 60% of the infants.

Conclusion

During an infant's hospital stay, LMB dispenses various human milk feeds with interspersed DHM resulting in complex intra-individual and time-variant feeding patterns. LMB dispenses raw MOM and especially raw DHM with the intention to retain the properties of human milk unlike a diet containing pasteurised DHM and/or formula. Although raw DHM comprises a small percentage of all dispensed milk, raw DHM is dispensed for a substantial portion of infants. Our results document that dispensing raw DHM, is possible in routine settings.

Case Report: I feel like a mother to other babies: experiences and perspectives on bereavement and breastmilk donation from Vietnam

There is a growing recognition globally that care regarding lactation following a perinatal death needs to potentially offer the opportunity for maternal donation. This article discusses this experience and perspectives from a human milk bank (HMB) in Vietnam. This is a descriptive exploratory case study that has a long tradition in both the social and health sciences. Triangulated data collection involved a review of video data, interview data with the donor, and data review for the Da Nang HMB, a Center for Excellence in Breastfeeding. We found that although it is common for mothers in Vietnam to donate breastmilk to HMBs, it is less common for this to occur following perinatal loss. We offer a descriptive case study of the maternal loss of twins and a subsequent choice to donate for approximately 1 month to the Da Nang HMB, the first HMB in Vietnam. We discuss four reasons derived from this case regarding donation following perinatal loss. (1) A strong motivation to donate breastmilk when aware of the service, (2) donating breastmilk helped her deal with grief, (3) family members supported her through this tough time and supported her decision, and (4) health staff supported her decision. While human milk sharing (e.g., wet nursing) has been practiced in Vietnam, breastmilk donation from bereaved mothers has neither been discussed nor well-researched. Because maternal grief is complex and individual, deciding to donate breastmilk is a personal decision that needs to be supported, without creating guilt for those who do not wish to donate.

Combined Nutrition in Very-Low-Birth-Weight Preterm Infants in the Neonatal Intensive Care Unit

Background Adequate nutritional support is crucial for achieving optimal growth and development in very-low-birth-weight (VLBW) preterm infants. This study evaluated the efficacy of combined nutrition (CN) (parenteral plus enteral nutrition (EN)) as an alternative nutrition protocol for VLBW infants in the neonatal intensive care unit (NICU). Methods This retrospective cohort study collected clinical and growth data from the medical records of VLBW infants weighing between 1,000 and 1,500 grams in the NICU of the Hospital of Obstetrics and Gynecology "Dr. Víctor Manuel Espinosa de los Reyes Sánchez" of the Centro Médico Nacional "La Raza" Instituto Mexicano del Seguro Social, Mexico. Parenteral nutrition (PN) alone or CN (PN plus EN) was used for nutritional management. Statistical tests, such as Student's t-test, Mann-Whitney U test, and chi-square test as appropriate, were used to compare the clinical characteristics and growth data of the two groups, and relative risk was calculated to determine the probability of comorbidities according to feeding type. Statistical significance was set at p<0.05. Results The study included 90 VLBW infants, with 27 receiving PN alone and 63 receiving CN. No statistically significant differences were found concerning sex, age, or Apgar score. The CN group showed better weight gain with statistically significant differences at 28 days (p=0.002), with no increase in the relative risk of necrotizing enterocolitis (NEC) or other complications. Conclusions The CN protocol met the caloric and nutritional needs, without increasing morbidity and mortality. The protocol had a positive impact on weight gain and a shorter NICU stay and should be considered as a nutritional alternative for VLBW infants.

Protein and Immune Component Content of Donor Human Milk in Japan: Variation with Gestational and Postpartum Age

Donor human milk (DHM) is the second-best nutrition for preterm infants when their own mother's milk is unavailable. The nutrient content of human milk is influenced by various factors, including gestational and postpartum age, but there are no data regarding DHM composition in Japan. The aim of this study was to determine the protein and immune component content of DHM in Japan and to elucidate the effects of gestational and postpartum age on nutrient composition. From September 2021 to May 2022, 134 DHM samples were collected from 92 mothers of preterm and term infants. Protein concentrations in preterm DHM (n = 41) and term DHM (n = 93) were analyzed using a Miris Human Milk Analyzer. The concentrations of secretory immunoglobulin A (sIgA) and lactoferrin, major immune components, were measured using enzyme-linked immunosorbent assays. Preterm DHM exhibited higher protein content than term DHM (1.2 g/dL and 1.0 g/dL, respectively, p < 0.001), whereas sIgA content was higher in term DHM than in preterm DHM (110 μg/mL and 68.4 μg/mL, respectively, p < 0.001). Gestational age was negatively correlated with protein levels and positively correlated with sIgA and lactoferrin levels. Furthermore, a negative correlation was found between postpartum week and protein, sIgA, and lactoferrin concentrations. Our data suggest that gestational and postpartum age affects protein, sIgA, and lactoferrin concentrations in DHM. These results indicate the importance of nutritional analysis for the appropriate use of DHM in preterm infants.

Racial capitalism and the US formula shortage: A policy analysis of the formula industry as a neocolonial system

The U.S. is currently experiencing a formula shortage and an infant feeding crisis that began with a formula recall and the hospitalization of 4 infants, 2 of whom died. Since 1981, governments around the world have been calling for an end to blatant human rights violations made by the commercial milk formula (CMF) industry. These practices not only involve targeting nutritionally vulnerable populations of mothers and newborns to turn a profit, but also actively undermining the implementation of policies, legislation, and regulatory oversight that might compromise their accumulation of wealth. In this paper we analyze the 2022 formula-shortage-as-infant-feeding-crisis through the lens of the history of colonialism and critical theory in the anthropology of reproduction. First, we provide an overview of the colonial roots of the formula industry from a global perspective. We then focus on how the mechanisms of racial exploitation remain entrenched in the U.S. approach to infant feeding policies, regulation and investment, setting the stage for the current infant feeding crisis. Through our analysis of the 2022 infant feeding crisis we demonstrate how the multinational CMF industry perpetuates racial capitalism and racialized health inequities and disparities through its operations as a neocolonial enterprise. Finally, we offer policy interventions and potential solutions that are grounded in structural interventions for more equitable, anticolonial, antiracist infant feeding systems.

Rural Nurses' Views on Breastmilk Banking in Limpopo Province, South Africa: A Qualitative Study

The development of breastmilk banks is being established among the African population, including in Limpopo Province. However, the views of nurses directly handling the donated breastmilk in the province remain unknown. This study was aimed at exploring and describing the views of nurses towards breastmilk banking in the Mankweng area, Limpopo Province. A qualitative, descriptive, and explorative study was undertaken at a tertiary hospital and a rural feeder clinic in the Mankweng area. Purposive sampling was employed to obtain participants for the interviews. One-on-one, semi-structured interviews were conducted to explore the views of these nurses. Data were analysed using Tesch’s open coding method, with the information obtained being grouped into different themes and sub-themes. Almost all nurses were willing to donate their breastmilk to the bank. However, receiving donated breastmilk for their own children seemed to be a challenge due to the safety of the donated breastmilk, uncertainty about the screening process, and cultural issues. Although donation of breastmilk appeared to be well supported by almost all the nurses, the use of donated breastmilk seemed to be not fully acceptable. Increased awareness about breastmilk donation and banking should be prioritised in the province.

Serratia marcescens outbreak in a neonatal intensive care unit associated with contaminated donor milk

Objective:

Investigation of the origin of a Serratia marcescens outbreak in a neonatal intensive care unit.

Design:

Retrospective case–control study.

Setting:

Regional level 3 perinatal center in Germany.

Patients:

This study included 4 S. marcescens–positive and 19 S. marcescens–negative neonates treated between February 1 and February 26, 2019, in the neonatal intensive care unit.

Methods:

A case–control study was performed to identify the source of the outbreak. The molecular investigation of S. marcescens isolates collected during the outbreak was performed using pulsed-field gel electrophoresis and next-generation sequencing.

Results:

The retrospective case–control study showed a significant correlation (P < .0001) between S. marcensens infection or colonization and consumption of donor milk that had tested negative for pathogenic bacteria from a single breast milk donor. Pulsed-field gel electrophoresis and next-generation sequencing retrospectively confirmed an S. marcescens strain isolated from the breast milk of this donor as the possible origin of the initial outbreak. The outbreak was controlled by the implementation of an infection control bundle including a multidisciplinary infection control team, temporary nutrition of infants with formula only and/or their mother’s own milk, repeated screening of all inpatients, strict coat and glove care, process observation, retraining of hand hygiene and continuous monitoring of environmental cleaning procedures.

Conclusions:

Low-level contaminated raw donor milk can be a source of infection and colonization of preterm infants with S. marcescens even if it tests negative for bacteria.