Rebeca Arroyo

Treatment of Infectious Mastitis during Lactation: Antibiotics versus Oral Administration of Lactobacilli Isolated from Breast Milk

BACKGROUND Mastitis is a common infectious disease during lactation, and the main etiological agents are staphylococci, streptococci, and/or corynebacteria. The efficacy of oral administration of Lactobacillus fermentum CECT5716 or Lactobacillus salivarius CECT5713, two lactobacilli strains isolated from breast milk, to treat lactational mastitis was evaluated and was compared with the efficacy of antibiotic therapy. METHODS In this study, 352 women with infectious mastitis were randomly assigned to 3 groups. Women in groups A (n = 124) and B (n = 127]) ingested daily 9 log(10) colony-forming units (CFU) of L. fermentum CECT5716 or L. salivarius CECT5713, respectively, for 3 weeks, whereas those in group C (n =101) received the antibiotic therapy prescribed in their respective primary care centers. Results. On day 0, the mean bacterial counts in milk samples of the 3 groups were similar (4.35-4.47 log(10) CFU/mL), and lactobacilli could not be detected. On day 21, the mean bacterial counts in the probiotic groups (2.61 and 2.33 log(10) CFU/mL) were lower than that of the control group (3.28 log(10) CFU/mL). L. fermentum CECT5716 and L. salivarius CECT5713 were isolated from the milk samples of women in the probiotic groups A and B, respectively. Women assigned to the probiotic groups improved more and had lower recurrence of mastitis than those assigned to the antibiotic group. Conclusions. The use of L. fermentum CECT5716 or L. salivarius CECT5713 appears to be an efficient alternative to the use of commonly prescribed antibiotics for the treatment of infectious mastitis during lactation. ClinicalTrials.gov identifier. NCT00716183.

Staphylococcus epidermidis: a differential trait of the fecal microbiota of breast-fed infants.

BackgroundBreast milk is an important source of staphylococci and other bacterial groups to the infant gut. The objective of this work was to analyse the bacterial diversity in feces of breast-fed infants and to compare it with that of formula-fed ones. A total of 23 women and their respective infants (16 breast-fed and 7 formula-fed) participated in the study. The 16 women and their infants provided a sample of breast milk and feces, respectively, at days 7, 14, and 35. The samples were plated onto different culture media. Staphylococcal and enterococcal isolates were submitted to genetic profiling and to a characterization scheme, including detection of potential virulence traits and sensitivity to antibiotics.ResultsThe feeding practice had a significant effect on bacterial counts. A total of 1,210 isolates (489 from milk, 531 from breast-fed and 190 from formula-fed infants) were identified. Staphylococcus epidermidis was the predominant species in milk and feces of breast-fed infants while it was less prevalent in those of formula fed-infants. Enterococcus faecalis was the second predominant bacterial species among the fecal samples provided by the breast-fed infants but it was also present in all the samples from the formula-fed ones. The biofilm-related icaD gene and the mecA gene were only detected in a low number of the S. epidermidis strains. Several enterococcal isolates were also characterized and none of them contained the cylA or the vanABDEG antibiotic-resistance genes. All were sensitive to vancomycin.ConclusionThe presence of S. epidermidis is a differential trait of the fecal microbiota of breast-fed infants. Globally, the staphyloccal isolates obtained from milk and feces of breast-fed infants contain a low number of virulence determinants and are sensitive to most of the antibiotics tested.

Staphylococcus epidermidis strains isolated from breast milk of women suffering infectious mastitis: potential virulence traits and resistance to antibiotics

BackgroundAlthough Staphylococcus aureus is considered the main etiological agent of infectious mastitis, recent studies have suggested that coagulase-negative staphylococci (CNS) may also play an important role in such infections. The aims of this work were to isolate staphylococci from milk of women with lactational mastitis, to select and characterize the CNS isolates, and to compare such properties with those displayed by CNS strains isolated from milk of healthy women.ResultsThe milk of 30 women was collected and bacterial growth was noted in 27 of them, of which Staphylococcus epidermidis was isolated from 26 patients and S. aureus from 8. Among the 270 staphylococcal isolates recovered from milk of women with mastitis, 200 were identified as Staphylococcus epidermidis by phenotypic assays, species-specific PCR and PCR sequencing. They were typified by pulsed field gel electrophoresis (PFGE) genotyping. The PFGE profiles of the S. epidermidis strains were compared with those of 105 isolates from milk of healthy women. A representative of the 76 different PFGE profiles was selected to study the incidence of virulence factors and antibiotic resistance. The number of strains that contained the biofilm-related icaD gene and that showed resistance to oxacillin, erythromycin, clindamycin and mupirocin was significantly higher among the strains isolated from mastitic milk.ConclusionS. epidermidis may be a frequent but largely underrated cause of infectious mastitis in lactating women. The resistance to diverse antibiotics and a higher ability to form biofilms found among the strains isolated from milk of women suffering mastitis may explain the chronic and/or recurrent nature of this infectious condition.

PCR-DGGE assessment of the bacterial diversity of breast milk in women with lactational infectious mastitis

BackgroundInfectious mastitis is a common condition during lactation and in fact, represents one of the main causes leading to a precocious weaning. The number of studies dealing with lactational mastitis is low and, up to now, the etiological diagnosis is frequently made on the basis of unspecific clinical signs. The aim of this study was to investigate the microbial diversity of breast milk in 20 women with lactational mastitis employing culture-dependent and culture-independent (PCR-DGGE) approaches.MethodsBreast milk samples were cultured in different media to investigate the presence of bacteria and/or yeasts, and a total of 149 representative isolates were identified to the species level by 16S rRNA gene PCR sequencing. The microorganisms recovered were compared with those found by PCR-DGGE analysis. To identify the DGGE profiles two reference markers of different microbial species were constructed. Sequence analysis of unknown bands was also performed.ResultsStaphylococci were the dominant bacterial group and Staphylococcus epidermidis was the dominant species. In a lower number of samples, other bacteria (mainly streptococci and a few gram-negative species) were also identified. Globally, PCR-DGGE results showed a good correlation with those obtained by culture-based methods. However, although DNA bands corresponding to different lactic acid bacteria were detected, such bacteria could not be isolated from the milk samples.ConclusionStaphylococci seem to be the main etiological agents of human lactational mastitis. The combined use of culture and molecular techniques allowed a better characterization of the bacterial diversity in milk from women suffering from infectious mastitis. Our results suggest that this condition could be the result of a disbiotic process where some of the bacterial species usually present in human milk outgrow (staphylococci) while others disappear (lactobacilli or lactococci).

Cold Storage of Human Milk: Effect on Its Bacterial Composition

Objectives:In the last few years, it has been proved that human milk contains bacteria that constitute an important factor in the initiation and development of the neonatal gut microbiota. In this context, the objective of this study was to evaluate the effect of cold storage on the natural bacterial composition of breast milk. Materials and Methods:Breast milk samples provided by 34 healthy women and collected either by manual expression (n = 27) or breast pump (n = 7), were plated onto several culture media immediately after arrival at the laboratory (day 0) and after storage at −20°C for 6 weeks. A high number of isolates from 8 of the women were identified at the species level. Results:No statistically significant differences were observed between the counts obtained at both sampling times in those media in which growth was detected. In all of the culture media, bacterial counts in pump-collected samples were higher than in those obtained by manual expression. Staphylococci and streptococci were the predominant bacteria in both fresh and frozen samples, Staphylococcus epidermidis being the most abundant species at both sampling times. Lactic acid bacteria and bifidobacteria were also present in fresh and frozen breast milk samples, but among them, only 1 species (Lactobacillus gasseri) could be isolated at both sampling times. Conclusions:The results of this study suggest that cold storage of milk at −20°C for 6 weeks does not significantly affect either the quantitative or the qualitative bacterial composition of breast milk.

Complete Genome Sequence of Lactobacillus fermentum CECT 5716, a Probiotic Strain Isolated from Human Milk

Lactobacillus fermentum is a heterofermentative lactic acid bacterium and is frequently isolated from mucosal surfaces of healthy humans. Lactobacillus fermentum CECT 5716 is a well-characterized probiotic strain isolated from human milk and, at present, is used in commercial infant formulas. Here, we report the complete and annotated genome sequence of this strain.

Multifunctional properties of soy milk fermented by Enterococcus faecium strains isolated from raw soy milk.

Lactic acid bacteria (LAB) isolated from soy milk were used to produce a multifunctional fermented food. Seven isolates were screened for their ability to produce peptides and free isoflavones in soy milk. The antihypertensive, antioxidant, and anti-inflammatory properties of the resulting fermented soy milks were evaluated in vitro using biochemical assays. Isolates 1-5 were found to be producers of fermented soy milk with angiotensin I converting enzyme inhibitory activity (ACEI). Isolate 3 was found to be a producer of free isoflavones that increased the antioxidant and anti-inflammatory potential of fermented soy milk. LAB isolates 2-5 were submitted to genetic profiling and a characterization scheme. These isolates were identified as Enterococcus faecium , and none of them contained virulence determinants or resistance to antibiotics. In conclusion, this study shows that the application of E. faecium isolate 3 for multifunctional food production from soy milk could be a promising strategy in the prevention therapy against cardiovascular disease.

Prevention of Infectious Mastitis by Oral Administration of Lactobacillus salivarius PS2 During Late Pregnancy

BACKGROUND Previous studies have shown that oral administration of lactobacilli can be an efficient approach to treat lactational infectious mastitis. In this trial, we have evaluated the potential of Lactobacillus salivarius PS2 to prevent this condition when orally administered during late pregnancy to women who had experienced infectious mastitis after previous pregnancies. METHODS In this study, 108 pregnant women were randomly assigned to one of 2 groups. Those in the probiotic group (n = 55) ingested daily 9 log10 colony-forming units of L. salivarius PS2 from approximately week 30 of pregnancy until delivery, whereas those in the placebo group (n = 53) received a placebo. The occurrence of mastitis was evaluated during the first 3 months after delivery. RESULTS Globally, 44 of 108 women (41%) developed mastitis; however, the percentage of women with mastitis in the probiotic group (25% [n = 14]) was significantly lower than in the control group (57% [n = 30]). When mastitis occurred, the milk bacterial counts in the probiotic group were significantly lower than those obtained in the placebo group. CONCLUSIONS Oral administration of L. salivarius PS2 during late pregnancy appears to be an efficient method to prevent infectious mastitis in a susceptible population. CLINICAL TRIALS REGISTRATION NCT01505361.

Microbial Diversity in Milk of Women With Mastitis: Potential Role of Coagulase-Negative Staphylococci, Viridans Group Streptococci, and Corynebacteria:

Background: Lactational mastitis constitutes a significant cause of premature weaning. However, its etiology, linked to the presence of pathogenic microorganisms, has been scarcely reported. Research aim: The aim of this study was to describe the microbial diversity in milk samples from women suffering from lactational mastitis and to identify more accurately a collection of isolates belonging to coagulase-negative staphylococci, streptococci, and coryneform bacteria. Methods: This is a cross-sectional descriptive one-group study. A total of 5,009 isolates from 1,849 mastitis milk samples was identified by culture, biochemical, and/or molecular methods at the species or genus level. A more precise identification of a collection of 211 isolates was carried out by 16S rRNA gene sequencing. Results: Mean total bacterial count in milk samples was 4.11 log10 colony-forming units/ml, 95% confidence interval [4.08, 4.15]. Staphylococcus epidermidis was the most common species being isolated from 91.56% of the samples, whereas Staphylococcus aureus was detected in 29.74%. Streptococci and corynebacteria constituted the second (70.20%) and third (16.60%) most prevalent bacterial groups, respectively, found in this study. In contrast, Candida spp. was present in only 0.54% of the samples. Sequencing of the 16S rRNA gene revealed a high diversity of bacterial species among identified isolates. Conclusion: Many coagulase-negative staphylococci, viridans group streptococci, and corynebacteria, usually dismissed as contaminant bacteria, may play an important role as etiologic agents of mastitis. Proper diagnosis of mastitis should be established after performing microbiological testing of milk based on standardized procedures. A reliable analysis must identify the mastitis-causing pathogen(s) at the species level and its(their) concentration(s).

Complete Genome Sequence of Bifidobacterium breve CECT 7263, a Strain Isolated from Human Milk

Bifidobacterium breve is an actinobacterium frequently isolated from colonic microbiota of breastfeeding babies. Here, we report the complete and annotated genome sequence of a B. breve strain isolated from human milk, B. breve CECT 7263. The genome sequence will provide new insights into the biology of this potential probiotic organism and will allow the characterization of genes related to beneficial properties.