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

Dpt. Nutrición, Bromatología y Tecnología de Alimentos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
BMC Microbiology (Impact Factor: 2.73). 02/2009; 9(1):82. DOI: 10.1186/1471-2180-9-82
Source: PubMed


Although 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.
The 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.
S. 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.

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    • "Isolates were coded according to their origin (the prefix M for milk and H for hand swabs). S. aureus Sa9, isolated from mastitis milk (García et al. 2007), and S. aureus ATCC 14458 were used as positive controls; Staphylococcus epidermidis F12 was used as a negative control (Delgado et al. 2009). All isolates were routinely cultured in tryptic soy broth (TSB, Scharlab) or in tryptic soy agar (TSA). "
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    ABSTRACT: Staphylococcus aureus is involved in human and animal infections. Because of mastitis in dairy cows, milk can be contaminated by enterotoxin-producing strains, which constitutes a food poisoning risk. Animal handlers can be asymptomatic carriers, becoming an additional source of contamination. This research aims to improve our understanding of Staphylococcus aureus in small-scale dairy systems in central Mexico. Samples were taken in 12 dairy farms and included composite milk (from the four teats) and hand swabs from each farmer. Of 149 presumptive S. aureus isolates, 102 (84 from cows; 18 from farmers) were accurately identified by molecular methods. The genetic variability of 43 randomly selected isolates was determined by RAPD-PCR, and of these, 38 were genetically distinct (≤90% similarity). Of the 38 distinct isolates, 78.9% harboured at least one enterotoxin-encoding gene (staphylococcal enterotoxin a (sea)-sed, seg, and/or sei), whereas 100% carried icaA-icaD genes and 28% carried the bap gene. The latter three genes are all involved in biofilm formation. Susceptibility to antibiotics, bacteriocins, and bacteriophages, was also assayed; 36.8% of isolates were resistant to penicillin G. Only five isolates were resistant to bacteriocins nisin A and AS-48, and phiPLA-RODI was the most effective bacteriophage, infecting all of the isolates. These results support the need to adopt management strategies to improve hygiene and milking practices in order to enhance herd health and diminish the risk of food poisoning associated with the consumption of raw milk cheese.
    Dairy Science and Technology 03/2015; 95:181-196. DOI:10.1007/s13594-014-0195-0 · 1.09 Impact Factor
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    • "In this sense, a negative association between Caesarean delivery and breastfeeding exists because postoperative care routines delay the onset of lactation, disrupt mother-infant interaction and inhibit infant suckling [20]. Peripartum antibiotherapy has emerged as a strong risk factor for human mastitis because it induces the selection for antibiotic-resistant bacteria in the mammary gland and the elimination of potential competitors [21,22]. Antibiotics also affect vaginal and intestinal microbiota of the mother [22] and the development of intestinal microbiota in the infant [23]. "
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    ABSTRACT: Background The purpose of this study was to identify potential predisposing factors associated with human infectious mastitis. Methods We conducted a case–control study among breastfeeding women, with 368 cases (women with mastitis) and 148 controls. Data were collected by a questionnaire designed to obtain retrospective information about several factors related to medical history of mother and infant, different aspects of pregnancy, delivery and postpartum, and breastfeeding practices that could be involved in mastitis. Bivariate analyses and multivariate logistic regression model were used to examine the relationship between mastitis and these factors. Results The variables significantly- and independently-associated with mastitis were cracked nipples (P < 0.0001), oral antibiotics during breastfeeding (P < 0.0001), breast pumps (P < 0.0001), topical antifungal medication during breastfeeding (P = 0.0009), mastitis in previous lactations (P = 0.0014), breast milk coming in later than 24 h postpartum (P = 0.0016), history of mastitis in the family (P = 0.0028), mother-infant separation longer than 24 h (P = 0.0027), cream on nipples (P = 0.0228) and throat infection (P = 0.0224). Conclusions Valuable factors related to an increased risk of infectious mastitis have been identified. This knowledge will allow practitioners to provide appropriate management advice about modifiable risk factors, such as the use of pumps or inappropriate medication. They also could identify before delivery those women at an increased risk of developing mastitis, such as those having a familial history of mastitis, and thus develop strategies to prevent this condition.
    BMC Pregnancy and Childbirth 06/2014; 14(1):195. DOI:10.1186/1471-2393-14-195 · 2.19 Impact Factor
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    • "The infectious aetiology of lactational mastitis is usually so high that some authors define the term " mastitis " as an infectious process of the mammary gland, involving staphylococci, streptococci and/or corynebacteria [2] [4]. Traditionally, Staphylococcus aureus has been considered as the main aetiological agent of acute mastitis , although Staphylococcus epidermidis is emerging as the leading cause of both subacute and chronic mastitis in human medicine [5] [6] [7]. Multiresistance to antibiotics and/or formation of biofilms is very common among clinical isolates of these two staphylococcal species. "
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    ABSTRACT: Infectious mastitis is a common condition among lactating women, with staphylococci and streptococci being the main aetiological agents. In this context, some lactobacilli strains isolated from breast milk appear to be particularly effective for treating mastitis and, therefore, constitute an attractive alternative to antibiotherapy. A (1)H-NMR-based metabolomic approach was applied to detect metabolomic differences after consuming a probiotic strain (Lactobacillus salivarius PS2) in women with mastitis. Before 24h urine of women with lactational mastitis was collected at baseline and after 21 days of probiotic (PB) administration. Multivariate (OSC-PLS-DA and hierarchical clustering) analysis showed metabolome differences after PB treatment. The discriminant metabolites detected at baseline of the intervention were lactose, and ibuprofen and acetaminophen (two pharmacological drugs commonly used for mastitis pain), while, after PB intake, creatine and the gut microbial co-metabolites hippurate and TMAO were detected. In addition, a voluntary desertion of the pharmacological drugs ibuprofen and acetaminophen was observed after probiotic administration. The application of NMR-based metabolomics enabled the identification of the overall effects of probiotic consumption among women suffering from mastitis and highlighted the potential of this approach in evaluating the outcomes of probiotics consumption.To our knowledge; this is the first time that this approach has been applied in women with mastitis during lactation.
    Pharmacological Research 05/2014; 87. DOI:10.1016/j.phrs.2014.05.010 · 4.41 Impact Factor
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