Łukasz Grześkowiak

University of Turku, Turku, Province of Western Finland, Finland

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Publications (7)13.01 Total impact

  • Łukasz Grześkowiak, Maria Carmen Collado, Seppo Salminen
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    ABSTRACT: Bacterial aggregation is related to cell-to-cell adherence between bacteria of the same or different strains. This phenomenon is known to have an important role in microbial interactions and in aquaculture.The aim of the present study was to evaluate the aggregation properties of bacterial candidates for fish probiotics and to assess these properties in viable and non-viable forms with fish bacterial pathogens.The microorganisms Leuconostoc citreum and Enterococcus durans in viable and non-viable forms were evaluated with fish pathogens Aeromonas hydrophila, Aeromonas salmonicida, Edwardsiella tarda and Vibrio anguillarum.L. citreum showed higher auto-aggregation properties in non-viable vs. viable form (P = 0.005). The co-aggregation percentage of viable L. citreum + A. hydrophila differed from those of L. citreum + E. tarda, and L. citreum + V. anguillarum (P = 0.033, P = 0.013, respectively). The co-aggregation abilities with A. salmonicida and E. tarda were higher with non-viable than viable cells of this microorganism (P = 0.023 and P = 0.020, respectively). Non-viable form of E. durans co-aggregated at different percentage with A. hydrophila compared to A. salmonicida and to E. tarda (P = 0.023, P = 0.030, respectively).The results suggest that the ability to auto- and co-aggregate with pathogens can be a useful tool for preliminary screening in order to identify potential probiotic bacteria suitable for use in aquaculture.
    Aquaculture 08/2012; 356-357:412-414. DOI:10.1016/j.aquaculture.2012.04.015 · 1.83 Impact Factor
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    ABSTRACT: Specific probiotic combinations during early feeding, via the mother or incorporated in early formula-feeding, mold the intestinal microbiota composition in infants. The objective was to analyze the impact of probiotic administration to mother or infant on gut microbiota composition in 6-month-old Finnish and German infants. In Finland probiotics were given to mothers (n = 79) for 2 months prior to and 2 months after delivery. In Germany probiotics were started in infants (n = 81) at weaning, at the latest at 1 month of age, and continued for 4 months. A breast-fed group of 6-month-old infants (22 from Finland, 8 from Germany) were compared. Gut microbiota were analyzed by FCM-FISH and qPCR methods. In breast-fed infants a trend toward higher counts of bifidobacteria was detected in Finland (p = 0.097) as against Germany, where a more diverse microbiota was reflected in higher Akkermansia (p = 0.003), Clostridium histolyticum (p = 0.035) and Bacteroides-Prevotella (p = 0.027) levels and a higher percentage of Akkermansia (p = 0.004). Finnish LPR + BL999 intervention group (Lactobacillus rhamnosus LPR and Bifidobacterium longum BL999) had higher percentages of fecal Lactobacillus-Enterococcus (9.0% vs. 6.1% placebo, p = 0.003) and lower bifidobacteria levels (10.03 log cells/g vs. 10.68 log cells/g placebo, p = 0.018). Probiotic treatment had different impacts on gut microbiota composition in Finnish and German infants due to differences in mode of feeding and the early commensal microbiota. Probiotic treatment had different impacts on gut microbiota composition in Finnish and German infants due to differences in mode of feeding and the basic commensal microbiota.
    Anaerobe 02/2012; 18(1):7-13. DOI:10.1016/j.anaerobe.2011.09.006 · 2.36 Impact Factor
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    ABSTRACT: The intestinal microbiota composition in infants reflects the early environment. Our objective was to compare the gut microbiota in 6-month-old infants living in rural Malawi with children of the same age living in urban Finland, both being breast-fed and having an age-appropriate diet typical for each area. Malawian 6-month-old infants (n=44) were compared with Finnish infants (n=31) of the same age. In both cohorts, infant stool samples were available for microbiota characterization by flow cytometry-fluorescent in situ hybridization and quantitative polymerase chain reaction methods. Bifidobacteria were dominant at 6 months of age in all of the infants, although in greater proportions in Malawian (70.8%) than in Finnish infants (46.8%; P<0.001). Additional distinctions in bacterial group composition comprised Bacteroides-Prevotella (17.2% vs 4.7%; P<0.001) and Clostridium histolyticum (4.4% vs 2.8%; P=0.01), respectively. The species Bifidobacterium adolescentis, Clostridium perfringens, and Staphylococcus aureus were absent in Malawian but detected in Finnish infants. The gut microbiota of 6-month-old infants in a low-income country differs significantly from that in a high-income country. This may have an effect on both the energy harvest from the diet typifying malnutrition and diarrheal diseases in low-income countries and Western lifestyle diseases in high-income countries.
    Journal of pediatric gastroenterology and nutrition 01/2012; 54(6):812-6. DOI:10.1097/MPG.0b013e318249039c · 2.18 Impact Factor
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    ABSTRACT: Adhesion to the host mucus represents the first crucial step in most infections caused by pathogenic bacteria. To characterize this phenomenon, the adhesion of Aeromonas hydrophila, Aeromonas salmonicida, Edwardsiella tarda and Vibrio anguillarum to mucus from different parts of three fish species was analyzed. Furthermore, the adherence of two commensal bacteria isolated from fish, Leuconostoc citreum and Enterococcus durans was assessed. To determine whether the observed bacterial adhesion to fish mucus was caused by non-specific interactions, adhesion to bovine serum albumin (BSA), gelatin and polystyrene was also tested. Our results demonstrated that non-specific adhesion such as hydrophobic interactions are only partially involved in the binding process since adhesion to BSA was low, and there was no correlation between adhesion to polystyrene and adhesion to fish mucus.These results indicate the need for a case-by-case assessment in order to select strains with the further ability to inhibit or displace specific pathogens. Specific probiotics selected for further pathogen exclusion could be useful tools to reduce and/or to prevent common fish infections.
    Aquaculture 07/2011; 318(1-2):33-36. DOI:10.1016/j.aquaculture.2011.04.037 · 1.83 Impact Factor
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    ABSTRACT: The aim here was to elucidate the mother-infant association in the gut colonization of 1-6 month-old infants and to establish whether probiotics can influence this process. Fecal samples from 80 mother-infant pairs were analyzed at 1 month (mothers and infants) and 6 months (infants) by real-time polymerase chain reaction to assess bacterial numbers. This double-blind placebo-controlled trial involved 2 different probiotic combinations (1. Lactobacillus rhamnosus + Bifidobacterium longum and 2. Lactobacillus paracasei + Bifidobacterium longum) given to the mothers 2 months prior to and 2 months after delivery. Bifidobacterium bifidum colonization in the mothers significantly increased the infants' probability of being colonized by B. bifidum and their bifidobacterial diversity indexes (DI) and the mother-infant similarity indexes (SI) both at 1 and 6 months of age. The counts of Bifidobacterium genus (at 1 month) and Bifidobacterium longum (at 6 months) correlated between mothers and infants. At 6 months, a significant effect of the probiotic intervention was found in the mother-infant association of fecal bifidobacterial counts but not in the colonization frequencies, DI or SI. In conclusion, a clear association between mother and infant was found in gut colonization by bifidobacteria. Maternal colonization by B. bifidum had the most consistent effects on the infant's bifidobacterial microbiota. Maternal probiotic treatment had little effect on this mother-infant association.
    Gut Microbes 01/2011; 2(4):227-33. DOI:10.4161/gmic.2.4.16799
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    ABSTRACT: Production and manufacturing methods and the food carrier may influence the properties of probiotic strains, and have an impact on the outcome of clinical intervention studies. The aim of the present study was to establish whether the properties of a specific probiotic strain, Lactobacillus rhamnosus GG, may differ depending on the product and source of the strain. In total, fifteen different L. rhamnosus isolates, among them fourteen labelled as L. rhamnosus GG, were isolated from specific probiotic products. The micro-organisms were phenotypically and genotypically characterised. Their adhesion properties were compared using the human intestinal mucus model, and the ability of the isolates to influence model pathogen adhesion to human colonic mucus was assessed. All L. rhamnosus isolates used were confirmed as members of the species L. rhamnosus. Except the reference strain OL, all L. rhamnosus isolates showed randomly amplified polymorphic DNA, enterobacterial repetitive intergenic consensus and pulsed-field gel electrophoresis profiles identical to that of L. rhamnosus GG (ATCC 53103). All L. rhamnosus isolates showed similar tolerance to acid and were able to bind to human colonic mucus. However, pathogen exclusion by inhibition and competition varied significantly among the different L. rhamnosus isolates and pathogens tested. The results suggest that different sources of the same probiotic may have significantly altered strain properties. This should be considered in in vivo studies on human subjects and also for quality control of probiotic products.
    The British journal of nutrition 11/2010; 105(6):887-94. DOI:10.1017/S0007114510004496 · 3.45 Impact Factor
  • M C Collado, Łukasz Grześkowiak, Seppo Salminen
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    ABSTRACT: The aim of this study was to investigate in vitro the protective effect of commercial probiotic strains (Bifidobacterium lactis Bb12 and Lactobacillus rhamnosus LGG) alone and in combination on the adhesion of pathogenic strains as Salmonella, Clostridium, and Escherichia coli to pig intestinal mucus obtained from different intestinal regions. In combination, probiotic strains enhanced each other's adhesion, mainly in large intestinal mucus. Treatment of intestinal mucus with Bb12 and LGG, alone or in combination, significantly reduced (P < 0.05) the adhesion of the tested pathogens. The ability to inhibit pathogen adhesion appears to depend on the specific probiotics and pathogens and on the mucosal site. B. lactis Bb12 and L. rhamnosus LGG in combination revealed a better ability to inhibit adhesion of all pathogens tested to pig intestinal mucus than probiotic strains. Probiotic combinations could be useful for counteracting disease-associated aberrations in intestinal microbiota. Specific protective probiotics could be selected for particular pig pathogens. Probiotic strains from human origin and intended for human use also adhere to pig intestinal mucus and are able to displace and inhibit pathogens.
    Current Microbiology 09/2007; 55(3):260-5. DOI:10.1007/s00284-007-0144-8 · 1.36 Impact Factor