title: Characterization of Staphylococcus aureus strains isolated from faeces of healthy neonates and potential mother-to-infant microbial transmission through breastfeeding.
abstract: Twenty-one women and their respective singleton infants participated in this study, contributing with samples of breast milk and faeces (at days 7, 14 and 35 after birth), respectively, used for Staphylococcus aureus recovery. The aim was to track the carriage of S. aureus in milk and infant faeces of mother-infant pairs, and to determine the genetic lineages of the isolates, their potential clonal relationships and their content in antimicrobial resistance, virulence and immune evasion cluster genes. The molecular characterization was performed by PCR and sequencing. Clonal relationship among mother-infant isolates was conducted by spa typing, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Staphylococcus aureus was isolated from milk samples of 6 of 21 mothers (16 isolates) and from faecal samples of 12 of 21 infants (25 isolates). From these 41 S. aureus recovered, 18 were methicillin-resistant (MRSA) and 23 methicillin-susceptible (MSSA). Twelve diferentes spa types and eight sequence types were detected among S. aureus. Predominant clonal complexes were CC5 (43.9%) and CC30 (36.6%). MRSA strains presented a multidrug-resistance profile, 65.2% of MSSA strains harboured tsst-1 toxin gene and 26.8% of total strains carried the cna gene. A potential mother-to-infant S. aureus transmission was demonstrated in four cases by spa typing, MLST and PFGE (transmission of t322/ST5/CC5-PFGE-A, t136/ST34/CC30-PFGE-B and t021/ST1869/CC30-PFGE-C strains). Breastfeeding seems to contribute to early S. aureus intestinal colonization in neonates what might affect the immune system development.
authors.affiliation: Área de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Benito
authors.affiliation: Área de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Lozano
authors.affiliation: ProbiSearch, S.L., Tres Cantos, 28760 Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Jiménez
authors.affiliation: Servei de Pediatria, Hospital Joan XXIII, 43007 Tarragona, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Albújar
authors.affiliation: Servei de Pediatria, Hospital Joan XXIII, 43007 Tarragona, Spain.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Gómez
authors.affiliation: ProbiSearch, S.L., Tres Cantos, 28760 Madrid, Spain Departamento de Nutrición, Bromatología y Tecnología de los Alimentos, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Rodríguez
authors.affiliation: Área de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain carmen.torres@unirioja.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: Torres
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics; D000328:Adult; D001427:Bacterial Toxins / Q000235:genetics; D001483:Base Sequence; D001942:Breast Feeding / Q000009:adverse effects*; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004768:Enterotoxins / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D018445:Infectious Disease Transmission, Vertical; D008712:Methicillin / Q000494:pharmacology; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D008895:Milk, Human / Q000382:microbiology; D058885:Multilocus Sequence Typing; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000382:microbiology / Q000635:transmission*; D018089:Superantigens / Q000235:genetics
chemical_list: D018829:Adhesins, Bacterial; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004768:Enterotoxins; D018089:Superantigens; C048165:adhesin, Staphylococcus aureus; C030107:enterotoxin F, Staphylococcal; D008712:Methicillin
keywords: breastfeeding Staphylococcus aureus transmission; methicillin-resistant; neonate faecal carriage