| 1. |
- Dwibedi, Chinmay Kumar, et al.
(author)
-
Biological amplification of low frequency mutations unravels laboratory culture history of the bio-threat agent Francisella tularensis
- 2020
-
In: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 45
-
Journal article (peer-reviewed)abstract
- Challenges of investigating a suspected bio attack include establishing if microorganisms have been cultured to produce attack material and to identify their source. Addressing both issues, we have investigated genetic variations that emerge during laboratory culturing of the bacterial pathogen Francisella tularensis. Key aims were to identify genetic variations that are characteristic of laboratory culturing and explore the possibility of using biological amplification to identify genetic variation present at exceedingly low frequencies in a source sample. We used parallel serial passage experiments and high-throughput sequencing of F. tularensis to explore the genetic variation. We found that during early laboratory culture passages of F. tularensis, gene duplications emerged in the pathogen genome followed by single-nucleotide polymorphisms in genes for bacterial capsule synthesis. Based on a biological enrichment scheme and the use of high-throughput sequencing, we identified genetic variation that likely pre-existed in a source sample. The results support that capsule synthesis gene mutations are common during laboratory culture, and that a biological amplification strategy is useful for linking a F. tularensis sample to a specific laboratory variant among many highly similar variants.
|
|
| 2. |
- Granberg, Agnes, et al.
(author)
-
First-Time Mothers' Enjoyment of Breastfeeding Correlates with Duration of Breastfeeding, Sense of Coherence, and Parental Couple and Child Relation : A Longitudinal Swedish Cohort Study
- 2020
-
In: Nursing Research and Practice. - : Hindawi Publishing Corporation. - 2090-1429 .- 2090-1437. ; 2020
-
Journal article (peer-reviewed)abstract
- Objectives: Many women do not reach their own breastfeeding goals regarding duration of breastfeeding. Different factors influence breastfeeding, and to learn more about breastfeeding within a multidimensional and longitudinal perspective, further research is needed. Therefore, the aim of the present study was to investigate diverse factors correlated with first-time mothers' enjoyment of breastfeeding and breastfeeding duration, between childbirth and two years after birth.Methods: In a prospective longitudinal cohort study, 324 newly become mothers were followed. The Spearman correlation test was used to investigate factors correlated with the degree to which mothers enjoy breastfeeding and the duration of breastfeeding. The Mann-Whitney test was conducted for comparisons of demographic characteristics between mothers who did or did not breastfeed.Results: Among the mothers, 99.2% initiated breastfeeding after birth. Frequencies of breastfeeding were 54.8% at six months, 9.1% at one year, and 1.0% at two years. The degree to which the mother enjoyed breastfeeding was correlated positively with (1) the duration of breastfeeding, (2) more positive feelings for and relation to the child, (3) the partner's perceived relation to the child, (4) a higher sense of coherence, and (5) stronger perceived parental couple's relationship. Longer breastfeeding duration was correlated positively with (1) a higher degree of enjoyment of breastfeeding, (2) more positive relation to the child, and (3) stronger perceived parental couple's relationship. Additionally, breastfeeding during the first two hours after birth, more positive feelings for and relation to the child, and a higher degree of enjoyment of breastfeeding were more frequently reported among breastfeeding mothers, in comparison with not breastfeeding mothers.Conclusion: Mothers' subjective experience from breastfeeding, sense of coherence, and couple relationship with partner and relationship with the child are valuable factors in regard to breastfeeding.
|
|
| 3. |
- Karlsson, Edvin, et al.
(author)
-
Clonality of erythromycin resistance in Francisella tularensis
- 2016
-
In: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 0305-7453 .- 1460-2091. ; 71:10, s. 2815-2823
-
Journal article (peer-reviewed)abstract
- Objectives: We analysed diverse strains of Francisella tularensis subsp. holarctica to assess if its division into biovars I and II is associated with specific mutations previously linked to erythromycin resistance and to determine the distribution of this resistance trait across this subspecies. Methods:Three-hundred and fourteen F. tularensis subsp. holarctica strains were tested for erythromycin susceptibility and whole-genome sequences for these strains were examined for SNPs in genes previously associated with erythromycin resistance. Each strain was assigned to a global phylogenetic framework using genome-wide canonical SNPs. The contribution of a specific SNP to erythromycin resistance was examined using allelic exchange. The geographical distribution of erythromycin-resistant F. tularensis strains was further investigated by literature search. Results:There was a perfect correlation between biovar II strains (erythromycin resistance) and the phylogenetic group B.12. Only B.12 strains had an AaEuroS -> aEuroSC SNP at position 2059 in the three copies of the rrl gene. Introducing 2059C into an rrl gene of an erythromycin-susceptible F. tularensis strain resulted in resistance. An additional 1144 erythromycin-resistant strains were identified from the scientific literature, all of them from Eurasia. Conclusions:Erythromycin resistance in F. tularensis is caused by an A2059C rrl gene mutation, which exhibits a strictly clonal inheritance pattern found only in phylogenetic group B.12. This group is an extremely successful clone, representing the most common type of F. tularensis throughout Eurasia.
|
|
| 4. |
- Rahman, Anisur, et al.
(author)
-
Early life arsenic exposure, infant and child growth, and morbidity : a systematic review
- 2017
-
In: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 91:11, s. 3459-3467
-
Research review (peer-reviewed)abstract
- Epidemiological studies have suggested a negative association between early life arsenic exposure and fetal size at birth, and subsequently with child morbidity and growth. However, our understanding of the relationship between arsenic exposure and morbidity and growth is limited. This paper aims to systematically review original human studies with an analytical epidemiological study design that have assessed arsenic exposure in fetal life or early childhood and evaluated the association with one or several of the following outcomes: fetal growth, birth weight or other birth anthropometry, infant and child growth, infectious disease morbidity in infancy and early childhood. A literature search was conducted in PubMed, TOXLINE, Web of Science, SciFinder and Scopus databases filtered for human studies. Based on the predefined eligibility criteria, two authors independently evaluated the studies. A total of 707 studies with morbidity outcomes were identified, of which six studies were eligible and included in this review. For the growth outcomes, a total of 2959 studies were found and nine fulfilled the criteria and were included in the review. A majority of the papers (10/15) emanated from Bangladesh, three from the USA, one from Romania and one from Canada. All included studies on arsenic exposure and morbidity showed an increased risk of respiratory tract infections and diarrhea. The findings in the studies of arsenic exposure and fetal, infant, and child growth were heterogeneous. Arsenic exposure was not associated with fetal growth. There was limited evidence of negative associations between arsenic exposures and birth weight and growth during early childhood. More studies from arsenic-affected low- and middle-income countries are needed to support the generalizability of study findings.
|
|
| 5. |
|
|
