Colostrum of Healthy Slovenian Mothers: Microbiota Composition and Bacteriocin Gene Prevalence

Abstract

Microbial communities inhabiting the breast milk microenvironment are essential in supporting mammary gland health in lactating women and in providing gut-colonizing bacterial 'inoculum' for their infants’ gastro-intestinal development. Bacterial DNA was extracted from colostrum samples of 45 healthy Slovenian mothers. Characteristics of the communities in the samples were assessed by polymerase chain reaction (PCR) coupled with denaturing gradient gel electrophoresis (DGGE) and by quantitative real-time PCR (qPCR). PCR screening for the prevalence of bacteriocin genes was performed on DNA of culturable and total colostrum bacteria. DGGE profiling revealed the presence of Staphylococcus and Gemella in most of the samples and exposed 4 clusters based on the abundance of 3 bands: Staphylococcus epidermidis/Gemella, Streptococcus oralis/pneumonia and Streptococcus salivarius. Bacilli represented the largest proportion of the communities. High prevalence in samples at relatively low quantities was confirmed by qPCR for enterobacteria (100%), Clostridia (95.6%), Bacteroides-Prevotella group (62.2%) and bifidobacteria (53.3%). Bacterial quantities (genome equivalents ml-1) varied greatly among the samples; Staphylococcus epidermidis and staphylococci varied in the range of 4 logs, streptococci and all bacteria varied in the range of 2 logs, and other researched groups varied in the range of 1 log. The quantity of most bacterial groups was correlated with the amount of all bacteria. The majority of the genus Staphylococcus was represented by the species Staphylococcus epidermidis (on average 61%), and their abundances were linearly correlated. Determinants of salivaricin A, salivaricin B, streptin and cytolysin were found in single samples. This work provides knowledge on the colostrum microbial community composition of healthy lactating Slovenian mothers and reports bacteriocin gene prevalence.

Human Milk Microbial Community Structure Is Relatively Stable and Related to Variations in Macronutrient and Micronutrient Intakes in Healthy Lactating Women

“…Our data are generally similar to those previously published by others. For example, the microbial composition of colostrum we collected on day 2 postpartum was similar to that described by Obermajer et al ( 29 ). Unlike what was reported by Cabrera-Rubio et al ( 30 ), however, Weisella and Leuconostoc were only present in very low relative abundances (0.01% and 0.03%, respectively) in one colostrum sample we collected.…”

Systematic Review of the Human Milk Microbiota

“…The human milk microbiota may be involved in the development of infant innate immunity and serve as a functional link between maternal and infant gut microbiota 8 , 33 . This relationship is multifactorial and dependent on many potential confounding factors such as delivery mode, 21 , 34 – 39 antibiotic use, 15 , 18 and maternal obesity 22 , 26 , 40 . Infants exclusively breastfed have been shown to have a less diverse and rich intestinal microbiota in comparison to infants formula fed 41 , 42 .…”

“…The mission of the Human Microbiome Project is to characterize the human microbiome from multiple body sites, but the investigators did not include human milk as one of the 18 anatomical regions or body sites of interest 9 . Nonetheless, independent studies have analyzed the human milk microbiota 3 , 6 , 7 , 10 – 26 . Early studies using cultured breast milk isolated only a limited number of genera 6 .…”

“Omics” in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes

“…Furthermore, it is possible that the overgrowth of one bacterial component over the others could lead to dysbiosis and pathologic states (such as in mastitis) [ 161 ]. In fact, during mastitic infection, it has been demonstrated that microbiome lose their diversity, with a predominance of bacterial pathogen species [ 162 ].…”