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- Ahlinder, Jon, et al.
(författare)
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Upstream land use with microbial downstream consequences : iron and humic substances link to Legionella spp
- 2024
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 256
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Tidskriftsartikel (refereegranskat)abstract
- Intensified land use can disturb water quality, potentially increasing the abundance of bacterial pathogens, threatening public access to clean water. This threat involves both direct contamination of faecal bacteria as well as indirect factors, such as disturbed water chemistry and microbiota, which can lead to contamination. While direct contamination has been well described, the impact of indirect factors is less explored, despite the potential of severe downstream consequences on water supply. To assess direct and indirect downstream effects of buildings, farms, pastures and fields on potential water sources, we studied five Swedish lakes and their inflows. We analysed a total of 160 samples in a gradient of anthropogenic activity spanning four time points, including faecal and water-quality indicators. Through species distribution modelling, Random Forest and network analysis using 16S rRNA amplicon sequencing data, our findings highlight that land use indirectly impacts lakes via inflows. Land use impacted approximately one third of inflow microbiota taxa, in turn impacting ∌20–50 % of lake taxa. Indirect effects via inflows were also suggested by causal links between e.g. water colour and lake bacterial taxa, where this influenced the abundance of several freshwater bacteria, such as Polynucleobacter and Limnohabitans. However, it was not possible to identify direct effects on the lakes based on analysis of physiochemical- or microbial parameters. To avoid potential downstream consequences on water supply, it is thus important to consider possible indirect effects from upstream land use and inflows, even when no direct effects can be observed on lakes. Legionella (a genus containing bacterial pathogens) illustrated potential consequences, since the genus was particularly abundant in inflows and was shown to increase by the presence of pastures, fields, and farms. The approach presented here could be used to assess the suitability of lakes as alternative raw water sources or help to mitigate contaminations in important water catchments. Continued broad investigations of stressors on the microbial network can identify indirect effects, avoid enrichment of pathogens, and help secure water accessibility.
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- Börjesson, Stefan, 1979-, et al.
(författare)
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Detection of an IMI-2 carbapenemase-producing Enterobacter asburiae at a Swedish feed mill
- 2022
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Occurrence of multidrug resistant Enterobacteriaceae in livestock is of concern as they can spread to humans. A potential introduction route for these bacteria to livestock could be animal feed. We therefore wanted to identify if Escherichia spp., Enterobacter spp., Klebsiella spp., or Raoutella spp. with transferable resistance to extended spectrum cephalosporins, carbapenems or colistin could be detected in the environment at feed mills in Sweden. A second aim was to compare detected isolates to previous described isolates from humans and animals in Sweden to establish relatedness which could indicate a potential transmission between sectors and feed mills as a source for antibiotic resistant bacteria. However, no isolates with transferable resistance to extended-cephalosporins or colistin could be identified, but one isolate belonging to the Enterobacter cloacae complex was shown to be carbapenem-resistant and showing carbapenemase-activity. Based on sequencing by both short-read Illumina and long-read Oxford Nanopore MinIon technologies it was shown that this isolate was an E. asburiae carrying a bla IMI-2 gene on a 216 Kbp plasmid, designated pSB89A/IMI-2, and contained the plasmid replicons IncFII, IncFIB, and a third replicon showing highest similarity to the IncFII(Yp). In addition, the plasmid contained genes for various functions such as plasmid segregation and stability, plasmid transfer and arsenical transport, but no additional antibiotic resistance genes. This isolate and the pSB89A/IMI-2 was compared to three human clinical isolates positive for bla IMI-2 available from the Swedish antibiotic monitoring program Swedres. It was shown that one of the human isolates carried a plasmid similar with regards to gene content to the pSB89A/IMI-2 except for the plasmid transfer system, but that the order of genes was different. The pSB89A/IMI-2 did however share the same transfer system as the bla IMI-2 carrying plasmids from the other two human isolates. The pSB89A/IMI-2 was also compared to previously published plasmids carrying bla IMI-2, but no identical plasmids could be identified. However, most shared part of the plasmid transfer system and DNA replication genes, and the bla IMI-2 gene was located next the transcription regulator imiR. The IS3-family insertion element downstream of imiR in the pSB89A was also related to the IS elements in other bla IMI-carrying plasmids.
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- Elving, Josefine, et al.
(författare)
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Composting for avian influenza virus elimination
- 2012
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 78, s. 3280-3285
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Tidskriftsartikel (refereegranskat)abstract
- Effective sanitization is important in viral epizootic outbreaks to avoid further spread of the pathogen. This study examined thermal inactivation as a sanitizing treatment for manure inoculated with highly pathogenic avian influenza virus H7N1 and bacteriophages MS2 and phi 6. Rapid inactivation of highly pathogenic avian influenza virus H7N1 was achieved at both mesophilic (35 degrees C) and thermophilic (45 and 55 degrees C) temperatures. Similar inactivation rates were observed for bacteriophage phi 6, while bacteriophage MS2 proved too thermoresistant to be considered a valuable indicator organism for avian influenza virus during thermal treatments. Guidelines for treatment of litter in the event of emergency composting can be formulated based on the inactivation rates obtained in the study.
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- Elving, Josefine
(författare)
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Pathogen inactivation and regrowth in organic waste during biological treatment
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After proper sanitation treatment, organic wastes such as animal by-products, e.g.catering waste, slaughterhouse waste and manure can be used as fertilisers and soil conditioners and thereby contribute to a sustainable society. However, organic waste may contain pathogenic microorganisms and can thus present a health risk to both humans and animals if not properly treated. In the present thesis regrowth potential of Salmonella Typhimurium, Enterococcus spp. and coliforms in organic waste at psychrophilic and mesophilic temperatures and the time and temperature combinations required for pathogen inactivation during thermal treatments was investigated. This was done with the aim to contribute to hygienically safe recycling of organic waste. Pathogen growth was observed in active compost material as well as in fresh cattle manure. The growth potential decreased with increased maturity of the compost. In thermal treatment of fresh cattle manure, a treatment temperature of 52°C and a retention time of 17.2 h or a temperature of 55°C during 16.9 h were needed to achieve the reduction targets set by current EU regulation in terms of bacterial reduction. However, this time and temperature combination was not sufficient to achieve the reduction target of 3 log10 for parvovirus as a thermoresistant virus. The inactivation rate of Salmonella Senftenberg W775 and Enterococcus spp. were found to increase with increased moisture content whereas the opposite relationship between inactivation rate and moisture content was observed for viruses.
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| 9. |
- Elving, Josefine
(författare)
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Thermal treatment of organic waste and its function as a controlled risk mitigation strategy
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Land application of organic waste is a convenient disposal method, improves soil properties by adding organic matter and recycles plant nutrients. Used in this way, organic waste is a resource, but it can also be a transmission route for pathogens with animal and human origin, such as Salmonella, verotoxin-producing Escherichia coli (VTEC) and avian influenza virus (AIV). Many pathogens are known to be able to survive for long time periods in soil after land application of organic waste. The total amount of pathogens entering the environment is eventually reduced due to environmental factors, e.g. UV-light and desiccation. Mitigation strategies applied after land application, for instance holding times, can reduce the risk for disease transmission to grazing animals. However, it is difficult to predict the reduction occurring within a given time. Thus, controlled mitigation strategies, such as, sanitization treatments are therefore needed. This thesis investigated the effect of thermal treatment on the inactivation rate of bacterial and viral pathogens, aiming to produce a hygienically safe end-product. For thermal treatment of organic waste it is recommended to keep a temperature above 50°C. Some organisms, such as AIV, can be rapidly reduced at lower temperatures. However, many organisms show a slow reduction at lower temperatures and some bacterial pathogens, such as Salmonella, might even regrow. The reduction target of 5 log10, for Salmonella Senftenberg W775 and Enterococcus faecalis, can be reached within 11.7 h at a temperature of 50.5°C. To reach a 3 log10 reduction of the thermotolerant virus, in this case porcine parvovirus, sufficiently longer treatment times are needed, e.g. 42 h at 55°C. However, the use of such thermotolerant viruses in the validation process has been questioned. Making use of the less thermotolerant bacteriophage ΦX174, as a process indicator, indicates that the treatment recommendations concerning viral reduction could be lowered to 5.8 h at 55°C. Thermal treatment can ensure; that a hygienically safe end-product is obtained from organic waste, safe handling of material from AI outbreaks, and help in reducing the risk for pathogen transmission to the environment.
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- Ottosson, Jakob, et al.
(författare)
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Bevattningsvatten : kunskapsunderlag
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Livsmedel från växtriket kan i vissa fall sprida mikrobiologisk smitta. Bär, bladgrönt och groddarmedför en särskild risk. Det beror på att de ofta äts råa eller efter minimal tillredning. Vi värmer deminte innan vi äter dem.Om livsmedlen är kontaminerade är det med stor sannolikhet orsakat av bevattningen. Vattnet kan havarit påverkat av avföring. Det kan också bero på spillning från vilda djur. Även naturgödsel kanförorena produkterna vid stänk från jord.Syftet med detta projekt var att se över kvaliteten på vatten för bevattning i Sverige. Vi ville koppladet till mikrobiologiska risker och utifrån det ta fram underlag till nationella råd och riktlinjer. Måletär ”en säkrare produktion av ätfärdiga bär och grönsaker som bättre förebygger sjukdomsutbrott”.Det visade sig att kvaliteten på vattnet generellt sett var god hos odlarna i projektet. Det samma gällergrödor. I vatten hittade vi enstaka sjukdomsframkallande mikroorganismer och ESBL-bildande E. coli.Dessa hittade vi dock endast i ytvatten som var mer förorenade av avföring och spillning. Men endastett fåtal prov på gröda visade på högre fekal förorening. Majoriteten av dessa kom från en och sammaodlare, som bevattnade med vatten från en damm. Vi hittade inga patogener på grödor. Däremot var ettprov på vitkål positivt för ESBL-bildande E. coli.Vi gjorde en kvantitativ riskvärdering av Shigatoxinproducerande E. coli (STEC) från isbergssallat.Den visade att även en liten förorening orsakad av avföring och utan påvisade STEC-bakterier ibevattningsvattnet kan utgöra en risk för mag-och tarminfektion. Riskvärderingen kan användas somunderlag för att föreslå mikrobiologiska kriterier, till exempel på vattenkvalitet. Vi behöver dockbeakta osäkerheterna med värderingen. De viktigaste osäkerheterna var utsöndringen av ochpatogeniciteten hos STEC från infekterade nötkreatur. Hur mycket av dessa fastnar på den bevattnadegrödan? Hur stor är sannolikheten att infekteras vid låga doser (enstaka STEC-bakterier)? Och hur storär risken av stänk från jord?Det finns olika åtgärder att ta till för att minska sannolikheten för utbrott och sjukdomsfall. Dessa är 1.Kriterier för vattenkvalitet. 2: Rening av vatten som inte uppnår dessa kriterier. 3. Införa enuppehållstid mellan sista bevattning och skörd. 4. Dessutom kan konsumenterna skölja produkternainnan de konsumerar dem. Det är också viktigt att se till att hålla utrustningen ren, exempelvis rör ochmunstycken. På så vis undviks föroreningar och tillväxt av bakterier.Om ytvatten måste användas för bevattning under de sista två veckorna innan skörd bör ettprovtagningsprogram utformas. Proven bör då visa på låg fekal förorening samt avsaknad avSalmonella. I bästa fall bör ytvatten renas före bevattning. Detta kan göras till exempel med hjälp avfotokatalys, UV-ljus eller filtrering. De sista två dagarna före skörd bör dock endast vatten avdricksvattenkvalitet användas.I en framtid med sjunkande grundvattennivåer, torrare somrar och blötare vintrar finns ett behov av attsamla in vatten för bevattning. Det bör göras under höstregn och vårfloder, samt vintertid. Vattnet fårsedan lagras i magasin. Vatten från bevattningsmagasin kan behöva renas innan det används förbevattning beroende på hur skyddat magasinet är från föroreningar.
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