[Antimicrobial resistance of coliform isolates from expressed human milk]. / Resistência antimicrobiana de coliformes isolados de leite humano ordenhado.

The dispersion of potentially pathogenic, antibiotic-resistant microorganisms via expressed human milk can be considered a risk factor. The aim of this study was to contribute to a better understanding of coliform isolates from expressed human milk and their antimicrobial resistance profiles. The sampling scheme followed a totally randomized design, using 837 samples of expressed human milk. Of these, 71 (8.48%) were identified as contaminated with total coliforms, although in none of the samples did the population exceed 1.0x10(3) MPN/ml. Most of the microorganisms isolated (91.6%) belonged to only two species, Enterobacter cloacae and Klebsiella pneumoniae, which when subjected to antibiograms, revealed that several strains showed prior resistance to some of the antimicrobials tested. Coliforms may grow in expressed human milk if it is improperly stored, depleting protection factors and reducing the milk's nutritional value.

[Human colostrum: a natural source of probiotics?] / Colostro humano: fonte natural de probióticos?

OBJECTIVE: The aim of the present study was to obtain data on the microbiota of human colostrum, and to correlate it with a possible source of probiotics transferred from mother to infant during breastfeeding. METHODS: 70 samples of milked human colostrum were analyzed as to the presence of mesophylic, thermoduric, psychrotrophic, proteolytic, proteolytic-psychrotrophic, lipolytic microorganisms, molds and yeasts, Staphylococcus aureus, total coliforms, fecal coliforms, Group D Streptococcus species and lactic acid bacteria. RESULTS: the microbiological analyses revealed several classical groups of microorganisms: mesophylic (68.6%); thermoduric (38.6%); psychrotrophic (8.6%); proteolytic (15.7%); proteolytic-psychrotrophic (1,4%); lipolytic (4.3%); molds and yeasts (11.4%); Staphylococcus aureus (44.3%); total coliforms (7.2%); and lactic acid bacteria (37.2%), thus characterizing a diversified microbiota. Thermoduric-psychrotrophic microorganisms, fecal coliforms and Group D Streptococcus species were not identified in any of the samples. CONCLUSIONS: The results show a microbiota rich in lactic acid bacteria, which may work as probiotics if delivered to infants within the first days of life.

Contamination of expressed human breast milk with an epidemic multiresistant Staphylococcus aureus clone.

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major cause of outbreaks in intensive care units. Infants make up a sector of the population that presents a high risk for MRSA infections. Mother-to-infant transmission has been indicated as a possible cause of MRSA infections in neonates. The occurrence and characteristics of MRSA in samples of banked human milk were investigated by selective culture, antibiogram and pulsed-field gel electrophoresis. MRSA contamination was found in 11% of 500 samples of expressed, fresh-frozen milk from 500 different donors at five Brazilian milk banks. The great majority of the contaminated samples passed breast milk quality control criteria for dispensing as raw milk under Brazilian and American guidelines. Most of the MRSA isolates belonged to the Brazilian epidemic clone, which is reported to be widespread in several Brazilian states, in Argentina and in Portugal. It is concluded that expressed breast milk can be a reservoir of multiresistant S. aureus epidemic clones. Studies are necessary to assess the source of contamination and potential role of MRSA-contaminated milk in the transmission of MRSA to neonates.

Methicillin-resistant Staphylococcus aureus in human milk.

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.

Methicillin-resistant Staphylococcus aureus in human milk

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§C, population sizes were already higher than 9.4 x 105 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.