Methicillin-resistant Staphylococcus aureus in human milk.
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We collected and analyzed 500 samples of human milk, from five Brazilian cities (100 from each) to detect methicillin-resistant strains of Staphylococcus aureus (MRSA) producing enterotoxins. We found 57 strains of MRSA, and the mecA gene, responsible for resistance, was detected in all of them using a specific molecular probe. We examined 40 strains for the presence of four enterotoxins, after selecting a subset that included all strains from each region, except for the largest sample, from which 10 were randomly selected. Among these two presented enterotoxin B, and growth in human colostrum and trypicase soy broth. After 5 h of incubation at 37 degrees C, population sizes were already higher than 9.4 x 10(5) UFC/ml and enterotoxin was released into culture medium and colostrum. Our results stress the importance of hygiene, sanitary measures, and appropriate preservation conditions to avoid the proliferation of S. aureus in human milk. (+info)
Oral transmission of human immunodeficiency virus by infected seminal fluid and milk: a novel mechanism.
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Salivary transmission by the 30 million human immunodeficiency virus (HIV) carriers is rare, despite kissing, aerosolization, and dental treatment. The main protective mechanism of saliva is reported to be inactivation of HIV-transmitting leukocytes by its unique hypotonicity; however, the successful oral transmission of HIV by seminal fluid and milk is unexplained. Whether seminal fluid and milk successfully transmit HIV orally by overcoming the recipient's salivary hypotonic inactivation of HIV-transmitting leukocytes was tested. Isotonic salt solution and normal donor samples of milk, colostrum, seminal fluid, and blood were studied for their ability to overcome the salivary hypotonic inactivation. All samples, in physiologic volumes, prevented the hypotonic saliva from inactivating HIV-transmitting leukocytes by providing solutes and retarding diffusion. This indicates that successful oral transmission of HIV by seminal fluid, milk, and colostrum may be due to their isotonicity, which overcomes hypotonic salivary inactivation of HIV-transmitting leukocytes. (+info)
Secretory anti-human immunodeficiency virus (HIV) antibodies in colostrum and breast milk are not a major determinant of the protection of early postnatal transmission of HIV.
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The immune response to human immunodeficiency virus (HIV) type 1 was evaluated in breast milk from HIV-infected African mothers who had transmitted and those who had not transmitted HIV to their children through breast-feeding. The levels, specific activities against gp160 and 2 HIV-derived peptides from gp41 and gp120 (V3 loop), and inhibitory activity toward viral transcytosis in vitro of secretory IgA (S-IgA) and IgG purified from breast milk were investigated in 8 transmitting mothers and 18 nontransmitting mothers. S-IgA and IgG antibodies to gp160 and to peptides were found in all breast milk samples. The specific activities of S-IgA and IgG to gp160 and peptides were similar between transmitting and nontransmitting mothers. No difference of the capacity of S-IgA and IgG to block HIV transcytosis in vitro was found between the 2 groups. These results suggest that humoral mucosal immunity to HIV does not appear as a predominant factor for protection against viral transmission through breast milk. (+info)
Brucellosis in a mother and her young infant: probable transmission by breast milk.
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Brucellosis, although primarily a zoonotic infection, is also a threat for human health. Infection can be transmitted to humans through direct contact with infected animals, products of conception, or animal discharges, and through consumption of potentially infected milk, milk products, or meat. Human-to-human transmission is rare. There have been case reports of transmission via blood transfusion and bone marrow transplantation from infected donors. Sexual intercourse is a possible means of transmission. Neonatal infection can be acquired transplacentally or during delivery. This report describes a mother with brucellosis who probably transmitted the infection to her 3-month-old baby by breast milk. (+info)
Evaluation of serum retinol, the modified-relative-dose-response ratio, and breast-milk vitamin A as indicators of response to postpartum maternal vitamin A supplementation.
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BACKGROUND: Conflicting results have been reported regarding the relative performance of serum retinol, the modified-relative-dose-response (MRDR) ratio, and breast-milk vitamin A concentrations in detecting changes in maternal vitamin A status. OBJECTIVE: We used receiver operating characteristic analyses and standardized differences to compare the ability of these indicators to detect a response to postpartum vitamin A supplementation in lactating Bangladeshi women. DESIGN: At 2 wk postpartum, women were randomly assigned to receive either a single dose of vitamin A [200000 IU (60000 retinol equivalents); n = 74] or placebo (n = 73). Data from maternal serum and breast milk collected 3 mo postpartum and from infant serum collected 6 mo postpartum were used to examine the ability of serum retinol, the MRDR ratio, and breast-milk vitamin A to discriminate between individuals in the supplemented and unsupplemented groups. Breast milk was collected by expressing the entire contents of one breast that had not been used to feed an infant for > or =2 h (full samples) or without controlling the time since the last breast-feeding episode (casual samples). RESULTS: Casual breast-milk samples performed better than full breast-milk samples in detecting a response to maternal supplementation. The MRDR ratio performed better than serum retinol in both the women and their infants. Overall, the most responsive indicator was the measurement of breast-milk vitamin A per gram of fat in casual breast-milk samples. CONCLUSIONS: Breast-milk vitamin A and the MRDR ratio are responsive indicators of vitamin A status, especially in women with mild vitamin A deficiency. (+info)
Randomized diet in the neonatal period and growth performance until 7.5-8 y of age in preterm children.
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BACKGROUND: Preterm children are at high risk of poor growth performance. In 2 randomized trials, preterm infants fed preterm formula grew better in the neonatal period than those fed banked donor breast milk or standard term formula. OBJECTIVE: Our objective was to test the hypothesis that for preterm infants, the neonatal period is a critical one for programming growth performance and that early diet influences long-term growth. DESIGN: A total of 926 preterm infants were recruited into 2 parallel, randomized trials of neonatal diet. In trial 1, infants were fed either banked donor breast milk or preterm formula whereas in trial 2, infants were fed either standard term formula or preterm formula. Within each trial, the allocated milk was the sole diet for some infants (study A), whereas for others it was a supplement to maternal breast milk, given when not enough expressed breast milk was available (study B). We followed up 781 of 833 survivors (94%) to age 7.5-8 y. Trained assessors obtained anthropometric measurements according to a standard protocol. RESULTS: Despite significantly better neonatal growth performance in infants fed preterm formula (compared with either banked donor breast milk or standard formula), early diet had no influence on weight, height, head circumference, or skinfold thicknesses at 9 or 18 mo postterm or at age 7.5-8 y. CONCLUSIONS: These findings suggest that the preterm period is not a critical window for nutritional programming of growth, which contrasts with evidence from these trials showing that early diet influences later neurodevelopment. (+info)
Inhibitors of complement activity in human breast-milk: a proposed hypothesis of their physiological significance.
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Several natural components abundant in the fluid phase of human breast-milk have been shown to be inhibitors of complement activation in vitro, particularly the classical pathway. These include lysozyme, lactoferrin, lactalbumin alpha and other ligand chelators, complement regulator proteins and other specific soluble inhibitors of complement activation. Their physiological significance probably resides in their ability to restrict in vivo complement activation to specialized (compartmentalized) sites on the cellular membrane structures in human milk, represented by the abundant surface area of the milk fat globule membranes. This would serve to prevent inflammatory-induced tissue damage of the delicate immature gastrointestinal tract of the newborn as well as the mammary gland itself. A number of recognized and potential inhibitors of complement activity in human milk and other biological fluids are hereby reviewed, with a proposal of their physiological significance. (+info)
Adverse host responses to bacterial toxins in human infants.
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Bacterial toxin interaction with the intestinal epithelium is regulated developmentally as well as by nutritional factors. It is the binding of bacterial toxins to the epithelium followed by several events that forms the basis of infantile diarrhea, a leading cause of morbidity and mortality world-wide. There has been increasing interest in bacterial toxin interaction with the enterocyte, postreceptor events that follow and the effect of developmental regulation on necrotizing enterocolitis. Diet and environmental factors can provide a major influence on bacterial-enterocyte interaction. Particularly important is the role of breast milk and its constituents, as well as probiotics, in this regard. The purpose of this review is to provide a brief overview on this complex interaction. (+info)