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- Bredholt, S., et al.
(författare)
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Microbial methods for assessment of cleaning and disinfection of food-processing surfaces cleaned in a low-pressure system
- 1999
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Ingår i: European Food Research and Technology. - 1438-2377 .- 1438-2385. ; 209:2, s. 145-152
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Tidskriftsartikel (refereegranskat)abstract
- An assessment system using various microbial methods was developed for the detection of residual, surface-attached microbes and soil on surfaces after sanitation. The microbial methods tested were: conventional cultivation, microscopy using image analysis after staining with acridine orange (AO), 5-cyano-2,3-ditolyl tetrazolium chloride/4?, 6-diamidino-2-phenylindole (CTC-DAPI) and LIVE/DEAD stains, impedance measurements, viable counts with 2,3,5-triphenyltetrazolium chloride (TTC) agar and ATP measurements. A test rig was used for the trials with four different low-pressure cleaning procedures (pressure ? 20 bar flow rate 271 min-1). A strong alkaline foam cleaner, Trippel, and a mild alkaline foam cleaner, Topax 12, in combination with two disinfectants, respectively, were used. The disinfectants were peroxide-peracetic-acid-based Oxonia Aktiv and potassium-persulphate-based Virkon. Conventional cultivation combined with impedance measurements and image analysis of surfaces stained with AO, as well as CTC-DAPI, gave results that were comparable and complementary. The combination of these methods enabled a total evaluation of both the removal of biofilm and the killing of bacterial cells. The low-pressure cleaning system did not remove all of the bacterial cells from the surfaces and did not kill the bacteria even after use of the strong alkaline foam cleaner. The above-mentioned protocol carried out on the test rig can also be used to evaluate the ensitivity of microbial methods for use in certain industrial premises. © Springer-Verlag 1999.
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- Paino, Annamari, et al.
(författare)
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Trimeric Form of Intracellular ATP Synthase Subunit β of Aggregatibacter actinomycetemcomitans Binds Human Interleukin-1β.
- 2011
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Ingår i: PloS one. - : Public Library of Science. - 1932-6203. ; 6:4, s. e18929-
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial biofilms resist host defenses and antibiotics partly because of their decreased metabolism. Some bacteria use proinflammatory cytokines, such as interleukin (IL)-1β, as cues to promote biofilm formation and to alter virulence. Although one potential bacterial IL-1β receptor has been identified, current knowledge of the bacterial IL-1β sensing mechanism is limited. In chronic biofilm infection, periodontitis, Aggregatibacter actinomycetemcomitans requires tight adherence (tad)-locus to form biofilms, and tissue destroying active lesions contain more IL-1β than inactive ones. The effect of IL-1β on the metabolic activity of A. actinomycetemcomitans biofilm was tested using alamarBlue™. The binding of IL-1β to A. actinomycetemcomitans cells was investigated using transmission electron microscopy and flow cytometry. To identify the proteins which interacted with IL-1β, different protein fractions from A. actinomycetemcomitans were run in native-PAGE and blotted using biotinylated IL-1β and avidin-HRP, and identified using mass spectroscopy. We show that although IL-1β slightly increases the biofilm formation of A. actinomycetemcomitans, it reduces the metabolic activity of the biofilm. A similar reduction was observed with all tad-locus mutants except the secretin mutant, although all tested mutant strains as well as wild type strains bound IL-1β. Our results suggest that IL-1β might be transported into the A. actinomycetemcomitans cells, and the trimeric form of intracellular ATP synthase subunit β interacted with IL-1β, possibly explaining the decreased metabolic activity. Because ATP synthase is highly conserved, it might universally enhance biofilm resistance to host defense by binding IL-1β during inflammation.
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- Razavi-Shearer, Devin M., et al.
(författare)
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Adjusted estimate of the prevalence of hepatitis delta virus in 25 countries and territories
- 2024
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Ingår i: JOURNAL OF HEPATOLOGY. - 0168-8278 .- 1600-0641. ; 80:2, s. 232-242
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Hepatitis delta virus (HDV) is a satellite RNA virus that requires the hepatitis B virus (HBV) for assembly and propagation. Individuals infected with HDV progress to advanced liver disease faster than HBV-monoinfected individuals. Recent studies have estimated the global prevalence of anti-HDV antibodies among the HBV-infected population to be 5-15%. This study aimed to better understand HDV prevalence at the population level in 25 countries/territories. Methods: We conducted a literature review to determine the prevalence of anti-HDV and HDV RNA in hepatitis B surface antigen (HBsAg)-positive individuals in 25 countries/territories. Virtual meetings were held with experts from each setting to discuss the findings and collect unpublished data. Data were weighted for patient segments and regional heterogeneity to estimate the prevalence in the HBV-infected population. The findings were then combined with The Polaris Observatory HBV data to estimate the anti-HDV and HDV RNA prevalence in each country/territory at the population level. Results: After adjusting for geographical distribution, disease stage and special populations, the anti-HDV prevalence among the HBsAg+ population changed from the literature estimate in 19 countries. The highest anti-HDV prevalence was 60.1% in Mongolia. Once adjusted for the size of the HBsAg+ population and HDV RNA positivity rate, China had the highest absolute number of HDV RNA+ cases. Conclusions: We found substantially lower HDV prevalence than previously reported, as prior meta-analyses primarily focused on studies conducted in groups/regions that have a higher probability of HBV infection: tertiary care centers, specific risk groups or geographical regions. There is large uncertainty in HDV prevalence estimates. The implementation of reflex testing would improve estimates, while also allowing earlier linkage to care for HDV RNA+ individuals. The logistical and economic burden of reflex testing on the health system would be limited, as only HBsAg+ cases would be screened.
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