825 research outputs found
A seasonal study of the mecA gene and Staphylococcus aureus including methicillin-resistant S. aureus in a municipal wastewater treatment plant
No full textThe spread of methicillin-resistant Staphylococcus aureus (MRSA), in which the mecA gene mediates resistance, threatens the treatment of staphylococcal diseases. The aims were to determine the effect of wastewater treatment processes on mecA gene concentrations, and the prevalence of S. aureus and MRSA over time. To achieve this a municipal wastewater treatment plant was investigated for the mecA gene, S. aureus and MRSA, using real-time PCR assays. Water samples were collected monthly for one year, at eight sites in the plant, reflecting different aspects of the treatment process. The mecA gene and S. aureus could be detected throughout the year at all sampling sites. MRSA could also be detected, but mainly in the early treatment steps. The presence of MRSA was verified through cultivation from inlet water. The concentration of the mecA gene varied between months and sampling sites, but no obvious seasonal variation could be determined. The wastewater treatment process reduced the mecA gene concentration in most months. Taken together our results show that the mecA gene, S. aureus and MRSA occur over the year at all sites investigated.Original Publication:Stefan Börjesson, Sara Melin, Andreas Matussek and Per-Eric Lindgren, A seasonal study of the mecA gene and Staphylococcus aureus including methicillin-resistant S. aureus in a municipal wastewater treatment plant, 2009, Water Research, (43), 4, 925-932.http://dx.doi.org/10.1016/j.watres.2008.11.036Copyright: Elsevier Science B.V., Amsterdam.http://www.elsevier.com
Nitrogen and methanogen community composition within and among three Sphagnum dominated peatlands in Scandinavia
No full textOmbrotrophic raised bogs are nutrient poor acidic peatlands accumulating organic matter. They are widely spread on northern latitudes and are substantial sources of methane emissions to the atmosphere being of great concern from a climate change perspective. We investigated the methanogen community composition along microtopographic gradients within three bogs in Scandinavia, receiving different amounts of nitrogen precipitation. Methanogenic community analyses by terminal restriction fragment length polymorphism of the mcrA gene showed different profiles among the three sites, while no in- fluence of the microtopographic gradients was observed. Peat temperature and dissolved organic carbon were the major edaphic variables explaining 38% of the variation of the methanogenic community di- versity among the bogs. The family Methanoregulaceae (hydrogenotrophic methanogens) showed the largest relative proportion and highest activity in all three sites. Quantitative PCR of the mcrA gene and transcripts showed that the most northern site, receiving the lowest atmospheric nitrogen load, had significantly lower abundance and activity of methanogens (4.7 106 and 2.4 104 mcrA copies per gram of soil, respectively), compared to the most southern site (8.2 107 and 4.6 105 mcrA copies per gram of soil, respectively), receiving the highest nitrogen load. No patterns of the mcrA gene and tran- script abundances were observed along the microtopography. The results indicated that the difference in occurrence of methanogens is mainly due to geoclimatological conditions rather than site intrinsic microtopographic variation. The study further suggests that environmental changes on the site intrinsic topography will not affect the methanogenic activity, while increasing average temperatures in Scan- dinavian ombrotrophic raised bogs might contribute to an increase of the methanogenic archaeal activity resulting in an increase of methane production.
Norovirus Gastroenteritis Outbreak with a Secretor-independent Susceptibility Pattern, Sweden
No full textNorovirus (NoV) is recognized as the commonest cause of acute gastroenteritis among adults. Susceptibility to disease has been associated with histo-blood group antigens and secretor status; nonsecretors are almost completely resistant to disease. We report a foodborne outbreak of GI.3 NoV gastroenteritis that affected 33/83 (40%) persons. Symptomatic disease was as likely to develop in nonsecretors as in secretors (odds ratio [OR] 1.41, 95% confidence interval [CI] 0.46-4.36 vs. OR 0.71, 95% Cl 0.23-2.18, p = 0.57). Moreover, no statistical difference in susceptibility was found between persons of different Lewis or ABO phenotypes. The capsid gene of the outbreak strain shares high amino acid homology with the Kashiwa645 GI.3 strain, previously shown to recognize nonsecretor saliva, as well as synthetic Lewis a. This norovirus outbreak affected persons regardless of secretor status or Lewis or ABO phenotypes.Original Publication:Johan Nordgren, Per-Eric Lindgren, Andreas Matussek and Lennart Svensson, Norovirus Gastroenteritis Outbreak with a Secretor-independent Susceptibility Pattern, Sweden, 2010, EMERGING INFECTIOUS DISEASES, (16), 1, 81-87.http://dx.doi.org/10.3201/eid1601.090633Licensee: National Center for Infectious Diseaseshttp://www.cdc.gov/ncidod/eid/index.ht
Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant
No full textNorovirs (NoV) is a leading cause of acute gastroenteritis and is often spread via wastewater contamination. Little is known about how the wastewater treatment process affects norovirus, and which factors influence virus concentrations. To investigate this, we collected wastewater samples monthly during one year at eight different key sites at the municipal wastewater treatment plant in Gothenburg, Sweden. Virus particles were concentrated using ultracentrifugation, viral RNA was subsequently extracted, and transformed into cDNA by reverse transcription. The quantification was performed with real-time PCR assays for NoV genogroups I (GGI) and II (GGII), respectively. We found seasonal changes of NoV genogroups, with the highest concentration of NoV GGII during the winter months, and the highest concentration of NoV GGI during the summer months. Virus transmission in wastewater was more stable for NoV GGI, with NoV GGII demonstrating larger seasonal peaks. Virus reduction took place at similar rates in the primary settling, and in the activated sludge in combination with the secondary settling. Different physicochemical parameters and incoming virus concentrations were correlated to reduction of NoV between different treatment sites. This study gives new information about NoV transmission and virus reduction in a wastewater treatment plant.Original Publication:Johan Nordgren, Andreas Matussek, Ann Mattsson, Lennart Svensson and Per-Eric Lindgren, Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant, 2009, Water Research, (43), 4, 1117-1125.http://dx.doi.org/10.1016/j.watres.2008.11.053Copyright: Elsevier Science B.V., Amsterdam.http://www.elsevier.com
Characterization of the bacterial microbiome of Swedish ticks through 16S rRNA amplicon sequencing of whole ticks and of individual tick organs
No full textBACKGROUND: The composition of the microbial flora associated with ixodid ticks has been studied in several species, revealing the importance of geographical origin, developmental stage(s) and feeding status of the tick, as well as substantial differences between tissues and organs. Studying the microbiome in the correct context and scale is therefore necessary for understanding the interactions between tick-borne pathogens and other microorganisms as well as other aspects of tick biology. METHODS: In the present study the microbial flora of whole Ixodes ricinus, I. persulcatus and I. trianguliceps ticks were analyzed with 16S rRNA amplicon sequencing. Additionally, tick organs (midguts, Malpighian tubules, ovaries, salivary glands) from flat and engorged I. ricinus female ticks were examined with the same methodology. RESULTS: The most abundant bacteria belonged to the group of Proteobacteria (Cand. Midichloria mitochondrii and Cand. Lariskella). 16S amplicon sequencing of dissected tick organs provided more information on the diversity of I. ricinus-associated microbial flora, especially when organs were collected from engorged ticks. Bacterial genera significantly associated with tick feeding status as well as genera associated with the presence of tick-borne pathogens were identified. CONCLUSIONS: These results contribute to the knowledge of microbial flora associated with ixodid ticks in their northernmost distribution limit in Europe and opens new perspectives for other investigations on the function of these bacteria, including those using other approaches like in vitro cultivation and in vitro models. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13071-022-05638-4
Low risk of developing Borrelia burgdorferi infection in the south-east of Sweden after being bitten by a Borrelia burgdorferi-infected tick
No full textObjectives: The risk of developing Lyme borreliosis (LB) from Borrelia burgdorferi sensu lato (Bb)-infected ticks in Sweden is largely unknown. In the current study, we investigated the prevalence of Bb in ticks that had bitten humans and the risk of developing LB from Bb-infected ticks. Methods: Health questionnaires, blood samples, and ticks were collected from 394 tick-bitten study subjects in the County of Ostergotland, Sweden, at the time of the tick bite. Questionnaires and blood samples were also collected 3 months later. Ticks were screened for Bb DNA with PCR, while sera were analyzed for antibodies against Bb using two ELISA assays. Seroconversion, i.e., an at least two-fold increase in anti-Bb antibodies after 3 months, was confirmed using a Strip-Immunoassay. Results: Seventy-five of 397 ticks collected from the study subjects were determined to be Bb-positive. Sixty-four of the tick-bitten subjects had been bitten by Bb-infected ticks. Four of them showed seroconversion and were therefore considered to have an active Bb infection. None of these four subjects had sought health care due to symptoms, but one reported symptoms. Conclusions: Our data suggest that the risk of developing LB after being bitten by a Bb-infected tick is low, and asymptomatic Bb infections appear to be more frequent than symptomatic infections.Original Publication: Linda Fryland, Peter Wilhelmsson, Per-Eric Lindgren, Dag Nyman, Christina Ekerfelt and Pia Forsberg, Low risk of developing Borrelia burgdorferi infection in the south-east of Sweden after being bitten by a Borrelia burgdorferi-infected tick, 2011, INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, (15), 3, E174-E181. http://dx.doi.org/10.1016/j.ijid.2010.10.006 Copyright: Elsevier Science B. V., Amsterdam http://www.elsevier.com
Vale Eric Carle: Creator of The Very Hungry Caterpillar, A Story of Hope ... and Holes
No full textEric Carle, author and illustrator of beloved children’s book, The Very Hungry Caterpillar, died on Sunday — the same day his famous caterpillar is born: 'One Sunday morning, the warm sun came up — and pop! — out of the egg came a very tiny and hungry caterpillar'. Described by author Mo Willems as a 'gentleman with a mischievous charm', Carle might have appreciated the irony. All living things grow and change and die. But while a caterpillar’s life is spectacularly short, Carle lived for 91 years. He wrote more than 70 books. His most celebrated, The Very Hungry Caterpillar, is frequently cited as one of the best picture books of all time. With just 224 words, it has sold roughly a copy per minute since its publication in 1969
Molecular preservation of the pigment melanin in fossil melanosomes.
No full textFossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this fundamental difference in interpretation is crucial: if endogenous then the fossil microbodies would represent a significant advancement in the fields of palaeontology and evolutionary biology given, for example, the possibility to reconstruct integumentary colours and plumage colour patterns. It has previously been shown that certain trace elements occur in fossils as organometallic compounds, and hence may be used as biomarkers for melanin pigments. Here we expand this knowledge by demonstrating the presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark
Prevalence and Diversity of Borrelia Species in Ticks That Have Bitten Humans in Sweden
No full textMembers of the genus Borrelia are among the most common infectious agents causing tick-borne disease in humans worldwide. Here, we developed a Light Upon eXtension (LUX) real-time PCR assay that can detect and quantify Borrelia species in ticks that have fed on humans, and we applied the assay to 399 such ticks. Borrelia PCR-positive ticks were identified to species level by sequencing the products of conventional PCR performed using Borrelia group-specific primers. There was a 19% prevalence of Borrelia spp. in the detached ticks, and the number of spirochetes per Borrelia PCR-positive tick ranged from 2.0 x 10(2) to 4.9 x 10(5), with a median of 7.8 x 10(3) spirochetes. Adult ticks had a significantly larger number of spirochetes, with a median of 8.4 x 10(4) compared to the median of nymphs of 4.4 x 10(4). Adult ticks also exhibited a higher prevalence of Borrelia (33%) than nymphs (14%). Among the identified species, Borrelia afzelii was found to predominate (61%) and was followed by B. garinii (23%), B. valaisiana (13%), B. burgdorferi sensu stricto (1%), B. lusitaniae (1%), and B. miyamotoi-like (1%). Also, 3% of the ticks were coinfected with multiple strains of B. afzelii. Notably, this is the first report of B. lusitaniae being detected in ticks in Sweden. Our LUX real-time PCR assay proved to be more sensitive than a corresponding TaqMan assay. In conclusion, the novel LUX real-time PCR method is a rapid and sensitive tool for detection and quantification of Borrelia spp. in ticks.Original Publication:Peter Wilhelmsson, Linda Fryland, Stefan Börjesson, Johan Nordgren, Sven Bergström, Jan Ernerudh, Pia Forsberg and Per-Eric Lindgren, Prevalence and Diversity of Borrelia Species in Ticks That Have Bitten Humans in Sweden, 2010, JOURNAL OF CLINICAL MICROBIOLOGY, (48), 11, 4169-4176.http://dx.doi.org/10.1128/JCM.01061-10Copyright: American Society for Microbiologyhttp://www.asm.org
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