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- Adlerberth, Ingegerd, 1959, et al.
(författare)
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Toxin-producing Clostridium difficile strains as long-term gut colonizers of healthy infants.
- 2014
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Ingår i: Journal of clinical microbiology. - 1098-660X. ; 52:1, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Clostridium difficile is a colonizer of the human gut, and toxin-producing strains may cause diarrhea if infectious burden is heavy. Infants are more frequently colonized than adults, but rarely develop C. difficile disease. It is not known whether strains of C. difficile differ in capacity to colonize and persist in the human gut microbiota. Here, we strain-typed isolates of C. difficile colonizing 42 healthy infants followed from birth to ≥12 months of age, using PCR ribotyping of the 16S-23S rRNA intergenic spacer region. The isolates were also characterized regarding carriage of the toxin genes tcdA, tcdB and cdtA/B, and capacity to produce toxin B in vitro. Most strains (71%) were toxin-producers, and 51% belonged to the 001 or 014 ribotypes, that often cause disease in adults. These ribotypes were significantly more likely than other ones to persist for ≥6 months in the infant micobiota, and were isolated from 13/15 children carrying such long-term colonizing strains. Ribotype 001 strains were often acquired in the first week of life and attained higher population counts than other C. difficile ribotypes in newborn infants' faeces. Several toxin-negative ribotypes were identified, two of which (GI and GIII) were long-term colonizers, each in one infant. Our results suggest that the toxin-producing C. difficile ribotypes 001 and 014 have special fitness in the infantile gut microbiota. Toxin-producing strains colonizing young children for long time periods may represent a reservoir for strains causing disease in adults.
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| 2. |
- Barman, Malin, 1983, et al.
(författare)
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High Levels of Both n-3 and n-6 Long-Chain Polyunsaturated Fatty Acids in Cord Serum Phospholipids Predict Allergy Development
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Background Long-chain polyunsaturated fatty acids (LCPUFAs) reduce T-cell activation and dampen inflammation. They might thereby counteract the neonatal immune activation and hamper normal tolerance development to harmless environmental antigens. We investigated whether fatty acid composition of cord serum phospholipids affects allergy development up to age 13 years. Methods From a population-based birth-cohort born in 1996/7 and followed until 13 years of age (n = 794), we selected cases with atopic eczema (n = 37) or respiratory allergy (n = 44), as well as non-allergic non-sensitized controls (n = 48) based on diagnosis at 13 years of age. Cord and maternal sera obtained at delivery from cases and controls were analysed for proportions of saturated, monounsaturated and polyunsaturated fatty acids among serum phospholipids. Results The cord serum phospholipids from subject who later developed either respiratory allergy or atopic eczema had significantly higher proportions of 5/8 LCPUFA species, as well as total n-3 LCPUFA, total n-6 LCPUFA and total LCPUFA compared to cord serum phospholipids from controls who did not develop allergy (P<0.001 for all comparisons). Conversely, individuals later developing allergy had lower proportion of the monounsaturated fatty acid 18:1n-9 as well as total MUFA (p<0.001) among cord serum phospholipids. The risk of respiratory allergy at age 13 increased linearly with the proportion of n-3 LCPUFA (Ptrend<0.001), n-6 LCPUFA (Ptrend = 0.001), and total LCPUFA (Ptrend<0.001) and decreased linearly with the proportions of total MUFA (Ptrend = 0.025) in cord serum phospholipids. Furthermore, Kaplan-Meier estimates of allergy development demonstrated that total LCPUFA proportion in cord serum phospholipids was significantly associated with respiratory allergy (P = 0.008) and sensitization (P = 0.002), after control for sex and parental allergy. Conclusion A high proportion of long-chain PUFAs among cord serum phospholipids may predispose to allergy development. The mechanism is unknown, but may involve dampening of the physiologic immune activation in infancy needed for proper maturation of the infant's immune system.
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| 3. |
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| 4. |
- Hesselmar, Bill, 1955, et al.
(författare)
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Pacifier Cleaning Practices and Risk of Allergy Development.
- 2013
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Ingår i: Pediatrics. - : American Academy of Pediatrics (AAP). - 1098-4275 .- 0031-4005. ; 131:6
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:Immune stimulation through exposure to commensal microbes may protect against allergy development. Oral microbes may be transferred from parents to infants via pacifiers. We investigated whether pacifier cleaning practices affected the risk of allergy development.METHODS:A birth-cohort of 184 infants was examined for clinical allergy and sensitization to airborne and food allergens at 18 and 36 months of age and, in addition, promptly on occurrence of symptoms. Pacifier use and pacifier cleaning practices were recorded during interviews with the parents when the children were 6 months old. The oral microbiota of the infants was characterized by analysis of saliva samples collected at 4 months of age.RESULTS:Children whose parents "cleaned" their pacifier by sucking it (n = 65) were less likely to have asthma (odds ratio [OR] 0.12; 95% confidence interval [CI] 0.01-0.99), eczema (OR 0.37; 95% CI 0.15-0.91), and sensitization (OR 0.37; 95% CI 0.10-1.27) at 18 months of age than children whose parents did not use this cleaning technique (n = 58). Protection against eczema remained at age 36 months (hazard ratio 0.51; P = .04). Vaginal delivery and parental pacifier sucking yielded independent and additive protective effects against eczema development. The salivary microbiota differed between children whose parents cleaned their pacifier by sucking it and children whose parents did not use this practice.CONCLUSIONS:Parental sucking of their infant's pacifier may reduce the risk of allergy development, possibly via immune stimulation by microbes transferred to the infant via the parent's saliva.
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| 5. |
- Lindberg, Erika, 1976, et al.
(författare)
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Effect of lifestyle factors on Staphylococcus aureus gut colonization in Swedish and Italian infants.
- 2011
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Ingår i: Clinical microbiology and infection. - : Elsevier BV. - 1469-0691 .- 1198-743X. ; 17:8, s. 1209-1215
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Tidskriftsartikel (refereegranskat)abstract
- Clin Microbiol Infect ABSTRACT: In recent years, Staphylococcus aureus has become a common bowel colonizer in Swedish infants. We aimed to identify host factors that determine such colonization. Stool samples from 100 Italian and 100 Swedish infants were obtained on seven occasions during the first year of life and cultured quantitatively for S.aureus. In a subgroup of infants in each cohort, individual strains were identified by random amplified polymorphic DNA analysis. Colonization at each time-point was related to delivery mode, siblings in family and antibiotic treatment. In total, 66% of the Italian and 78% of the Swedish infants had S.aureus in their stools on at least one time-point (p 0.08) and 4% of Italian and 27% of Swedish infants were positive on at least six of the seven time-points investigated (p0.0001). Most infants analysed regarding strain carriage harboured a single strain in their microbiota for several months. The S.aureus stool populations in colonized infants decreased from 10(7) to 10(4) colony-forming units/g between 1week and 1year of age in both cohorts. In multivariate analysis, the strongest predictor for S.aureus colonization was being born in Sweden (OR 3.4 at 1week of age, p0.002). Having (an) elder sibling(s) increased colonization at peak phase (OR 1.8 at 6months, p0.047). Antibiotic treatment was more prevalent among Italian infants and correlated negatively with S.aureus colonization at 6months of age (OR 0.3, p0.01). To conclude, S.aureus is a more common gut colonizer in Swedish than Italian infants, a fact that could not be attributed to feeding or delivery mode.
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| 6. |
- Lundell, Anna-Carin, 1976, et al.
(författare)
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High Proportion of CD5(+) B Cells in Infants Predicts Development of Allergic Disease
- 2014
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 193:2, s. 510-518
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Tidskriftsartikel (refereegranskat)abstract
- Delayed maturation of the immune system has been proposed to be a risk factor for development of allergy, but B cell maturation in relation to allergic disease has not been examined. B cells lose CD5 and acquire CD27 during maturation from immature via mature/naive to Ig-secreting cells and memory cells. We sought to investigate B cell maturation in relation to development of allergic disease and sensitization in the FARMFLORA birth cohort including 65 Swedish children. Total B cell numbers, proportions of CD5(+) and CD27(+) B cells, and levels of IgM, IgG, IgA, and IgE were measured in blood on repeated occasions from birth to 36 mo of age, and related to allergic disease and sensitization at 18 and 36 mo of age with multivariate discriminant analysis. We also compared the expression of CD24 and CD38 within CD5(+) and CD5(neg) B cells in children and in adults. We found that infants with a high proportion of CD5(+) B cells at birth and at 1 mo of age had an increased risk for having allergic disease at 18 and 36 mo of life. Further, the proportions of CD5(+) B cells at 1 mo of age were inversely correlated with total IgG levels at 18 and 36 mo of age. The majority of the CD5(+) B cells were of a CD24(hi/+)CD38(hi/+) immature/naive phenotype at birth (97%), 7 y of age (95%), and in adults (86%). These results suggest that development of allergic disease is preceded by an immaturity in neonatal B cell phenotype.
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| 7. |
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| 8. |
- Nowrouzian, Forough, 1957, et al.
(författare)
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Adhesin and superantigen genes and the capacity of Staphylococcus aureus to colonize the infantile gut.
- 2011
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Ingår i: The Journal of infectious diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 204:5, s. 714-21
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus aureus is a pathogen and a skin commensal that is today also common in the infant gut flora. We examine the role of S. aureus virulence factors for gut colonization. S. aureus isolated from quantitative stool cultures of 49 Swedish infants followed from birth to 12 months of age were assessed for 30 virulence-associated genes, spa type, and agr allele by serial polymerase chain reaction (PCR) assays. Strains carrying genes encoding collagen-binding protein, and the superantigens S. aureus enterotoxin O/M (SEO/SEM) had higher stool counts than strains lacking these genes, whereas genes for S. aureus enterotoxin A (SEA) were associated with low counts. A cluster of strains belonging to agr allele I and the spa clonal cluster 630 (spa-CC 630) that carried genes encoding SEO/SEM, SEC, collagen-binding protein, and elastin-binding protein were all long-time colonizers. Thus, certain S. aureus virulence factors might promote gut colonization.
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