Browsing by Subject "STRAINS"

Sort by: Order: Results:

Now showing items 1-20 of 47
  • Felix, Benjamin; Sevellec, Yann; Palma, Federica; Douarre, Pierre Emmanuel; Felten, Arnaud; Radomski, Nicolas; Mallet, Ludovic; Blanchard, Yannick; Leroux, Aurelie; Soumet, Christophe; Bridier, Arnaud; Piveteau, Pascal; Ascensio, Eliette; Hebraud, Michel; Karpiskova, Renata; Gelbicova, Tereza; Torresi, Marina; Pomilio, Francesco; Camma, Cesare; Di Pasquale, Adriano; Skjerdal, Taran; Pietzka, Ariane; Ruppitsch, Werner; Canelhas, Monica Ricao; Papic, Bojan; Hurtado, Ana; Wullings, Bart; Bulawova, Hana; Castro, Hanna; Lindström, Miia; Korkeala, Hannu; Steingolde, Zanete; Kramarenko, Toomas; Cabanova, Lenka; Szymczak, Barbara; Gareis, Manfred; Oswaldi, Verena; Marti, Elisabet; Seyfarth, Anne-Mette; Leblanc, Jean-Charles; Guillier, Laurent; Roussel, Sophie (2022)
    Listeria monocytogenes (Lm) is a ubiquitous bacterium that causes listeriosis, a serious foodborne illness. In the nature-to-human transmission route, Lm can prosper in various ecological niches. Soil and decaying organic matter are its primary reservoirs. Certain clonal complexes (CCs) are over-represented in food production and represent a challenge to food safety. To gain new understanding of Lm adaptation mechanisms in food, the genetic background of strains found in animals and environment should be investigated in comparison to that of food strains. Twenty-one partners, including food, environment, veterinary and public health laboratories, constructed a dataset of 1484 genomes originating from Lm strains collected in 19 European countries. This dataset encompasses a large number of CCs occurring worldwide, covers many diverse habitats and is balanced between ecological compartments and geographic regions. The dataset presented here will contribute to improve our understanding of Lm ecology and should aid in the surveillance of Lm. This dataset provides a basis for the discovery of the genetic traits underlying Lm adaptation to different ecological niches.
  • Pitkänen, Oskari; Markkula, Jukka; Hemming-Harlo, Maria (2022)
    Introduction: This study was performed to assess the prevalence and circulating genotypes of rotavirus, norovirus, and sapovirus in children. The results were compared to those of previous surveillance studies covering the years 20 06-20 08, 20 09-2011, and 2012-2014 with similar methodology and setting, encom-passing the start of universal vaccination with RotaTeq in 2009. Methods: Stool samples were collected from children aged < 16 years with acute gastroenteritis at Tam-pere University Hospital, Finland, from January 1, 2017 to December 31, 2018. The samples were analysed using reverse transcription PCR and positive amplicons were sequenced. Results: A total of 178 stool samples were collected from 214 children. Rotavirus was detected in 56 (32%) stool samples, norovirus in 48 (27%), and sapovirus in 11 (6.3%). Rotavirus G9P[8] and G12P[8] were the most detected genotypes in vaccinated and unvaccinated children. GII.4 comprised 96% of the norovirus detections. Conclusions: The prevalence of all-cause acute gastroenteritis in a hospital setting decreased by 51% com-pared to 2012-2014, and by 88% compared to 20 06-20 08 . Rotavirus returned as the most common cause of viral acute gastroenteritis in children, but the prevalence remains at a low level. No considerable changes were seen in the genotyping results of norovirus and sapovirus. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY-NC-ND license ( )
  • Jokela, Jouni; Oftedal, Linn; Herfindal, Lars; Permi, Perttu; Wahlsten, Matti; Doskeland, Stein Ove; Sivonen, Kaarina (2012)
  • Bui, Thi Phuong Nam; Troise, Antonio Dario; Fogliano, Vincenzo; de Vos, Willem M. (2019)
    Modifications of lysine contribute to the amount of dietary advanced glycation end-products reaching the colon. However, little is known about the ability of intestinal bacteria to metabolize dietary N-epsilon-carboxymethyllysine (CML). Successive transfers of fecal microbiota in growth media containing CML were used to identify and isolate species able to metabolize CML under anaerobic conditions. From our study, only donors exposed to processed foods degraded CML, and anaerobic bacteria enrichments from two of them used 77 and 100% of CML. Oscillibacter and Cloacibacillus evryensis increased in the two donors after the second transfer, highlighting that the bacteria from these taxa could be candidates for anaerobic CML degradation. A tentative identification of CML metabolites produced by a pure culture of Cloacibacillus evryensis was performed by mass spectrometry: carboxymethylated biogenic amines and carboxylic acids were identified as CML degradation products. The study confirmed the ability of intestinal bacteria to metabolize CML under anoxic conditions.
  • He, Suxu; Ran, Chao; Qin, Chubin; Li, Shuning; Zhang, Hongling; de Vos, Willem M.; Ringo, Einar; Zhou, Zhigang (2017)
    In this study, we tested the distribution of 49 Lactobacillus strains in the mucus and mucosa of the intestine tissue of zebrafish. We observed a progressive change in the spatial distribution of Lactobacillus strains, and suggested a division of the strains into three classes: mucus type (>70% in mucus), mucosa type (>70% in mucosa) and hybrid type (others). The hybrid type strains were more efficient in protection of zebrafish against Aeromonas hydrophila infection. Three strains representing different distribution types (JCM1149, CGMCC1.2028, and JCM 20300) were selected. The mucosa type strain JCM1149 induced higher intestinal expression of inflammatory cytokines and Hsp70 than the other strains. Furthermore, we used L. rhamnosus GG and its mutant (PB22) lacking SpaCBA pili to investigate the influence of pili on spatial distribution. LGG showed a mucosa type distribution, while PB22 revealed a hybrid distribution and the disease protection was accordingly improved. The different protection ability between LGG and PB22 did not involve the intestinal microbiota, however, LGG induced injury to the mucosa of zebrafish. Collectively, the disease protection activity of Lactobacillus in zebrafish is correlated with their spatial distribution in the intestinal tissue, with strains showing a balanced distribution (hybrid type) more efficient in protection.
  • Vilar, M. J.; Ranta, J.; Virtanen, S.; Korkeala, H. (2015)
    Bayesian analysis was used to estimate the pig's and herd's true prevalence of enteropathogenic Yersinia in serum samples collected from Finnish pig farms. The sensitivity and specificity of the diagnostic test were also estimated for the commercially available ELISA which is used for antibody detection against enteropathogenic Yersinia. The Bayesian analysis was performed in two steps; the first step estimated the prior true prevalence of enteropathogenic Yersinia with data obtained from a systematic review of the literature. In the second step, data of the apparent prevalence (cross-sectional study data), prior true prevalence (first step), and estimated sensitivity and specificity of the diagnostic methods were used for building the Bayesian model. The true prevalence of Yersinia in slaughter-age pigs was 67.5% (95% PI 63.2-70.9). The true prevalence of Yersinia in sows was 74.0% (95% PI 57.3-82.4). The estimates of sensitivity and specificity values of the ELISA were 79.5% and 96.9%.
  • Banić, Martina; Uroić, Ksenija; Leboš Pavunc, Andreja; Novak, Jasna; Zorić, Katarina; Durgo, Ksenija; Petković, Hrvoje; Jamnik, Polona; Kazazić, Saša; Kazazić, Snježana; Radović, Slobodanka; Scalabrin, Simone; Hynönen, Ulla; Šušković, Jagoda; Kos, Blaženka (2018)
    Abstract S-layers represent the simplest biological membranes developed during the evolution and are one of the most abundant biopolymers on Earth. Current fundamental and applied research aim to reveal the chemical structure, morphogenesis and function of S-layer proteins (Slps). This is the first paper that describes the Slps of certain Lactobacillus brevis strain isolated from sauerkraut. The whole genome sequence (WGS) analysis of the L. brevis SF9B strain uncovered three genes encoding the putative Slps, but merely one, identified as similar to the SlpB of L. brevis ATCC 14869, was expressed. Slp-expressing SF9B cells exhibited increased survival in simulated gastrointestinal (GI) conditions and during freeze-drying. Their survival in stress conditions was additionally enhanced by microencapsulation, especially when using alginate with gelatine as a matrix. Thus prepared cells were subjected to simulated GI conditions and their mortality was only 0.28 ± 0.45 log CFU/mL. Furthermore, a correlation between the high surface hydrophobicity and the remarkable aggregative capacity of SF9B strain was established. The results indicate a prominent role of Slps in adhesion to mucin, extracellular matrix (ECM) proteins, and particularly to Caco-2 cells, where the removal of Slps utterly abolished the adhesiveness of SF9B cells for 7.78 ± 0.25 log CFU/mL.
  • Turunen, Katri; Antikainen, Jenni; Lääveri, Tinja; Kirveskari, Juha; Svennerholm, Ann-Mari; Kantele, Anu (2020)
    Background: Enterotoxigenic Escherichia coli (ETEC) is a major pathogen causing travellers' diarrhoea (TD) among visitors to low- and middle-income countries (LMIC). Scant data are available on rates of travel-acquired ETEC producing heat-labile (LT) and/or heat-stable (ST) toxin or its subtypes, STh (human) and STp (porcine) in various geographic regions, and on clinical pictures associated with each toxin. Methods: Using qPCR, we analysed LT, STh, and STp in stools positive for ETEC in a prospective study among 103 Finnish travellers visiting LMIC. They filled in questionnaires and provided stool samples before and after travel. We scrutinized geographic distribution of LT, STh, and STp ETEC findings, and association between these different ETEC subtypes and moderate/severe TD. Results: Among the 103 stool samples positive for ETEC toxins, the rate for LT was 76%, for STh 26%, and STp 41%. The rate for LT-only was 44%, for 5Th-only 6%, STp-only 16%, LT + STh 10%, LT + STp 15%, STh + STp 3%, and LT + STh + STp 8%. Findings varied by destination; the rates of LT, STh, and STp were 79%, 21%, and 57%, respectively, in Southern Asia (n = 14); 85%, 10%, and 20% in South-eastern Asia (n = 20); 84%, 13%, and 29% in Eastern Africa (n = 31); and 56%, 50%, and 63% in Western Africa (n = 32), respectively. Of travellers positive for LT, STh, and STp, 83%, 100%, and 88%, encountered TD; 35%, 55%, and 41% reported moderate/severe TD. STh was associated with moderate/severe TD. Conclusions: Toxin findings varied by destination; multiple toxins were commonly detected. Moderate/severe TD was reported most frequently by subjects with STh-ETEC.
  • Lahti, Päivi; Lindström, Miia; Somervuo, Panu; Heikinheimo, Annamari; Korkeala, Hannu (2012)
    Clostridium perfringens, one of the most common causes of food poisonings, can carry the enterotoxin gene, cpe, in its chromosome or on a plasmid. C. perfringens food poisonings are more frequently caused by the chromosomal cpe-carrying strains, while the plasmid-borne cpe-positive genotypes are more commonly found in the human feces and environmental samples. Different tolerance to food processing conditions by the plasmid-borne and chromosomal cpe-carrying strains has been reported, but the reservoirs and contamination routes of enterotoxin-producing C. perfringens remain unknown. A comparative genomic hybridization (CGH) analysis with a DNA microarray based on three C. perfringens type A genomes was conducted to shed light on the epidemiology of C. perfringens food poisonings caused by plasmid-borne and chromosomal cpe-carrying strains by comparing chromosomal and plasmid-borne cpe-positive and cpe-negative C. perfringens isolates from human, animal, environmental, and food samples. The chromosomal and plasmid-borne cpe-positive C. perfringens genotypes formed two distinct clusters. Variable genes were involved with myo-inositol, ethanolamine and cellobiose metabolism, suggesting a new epidemiological model for C. perfringens food poisonings. The CGH results were complemented with growth studies, which demonstrated different myo-inositol, ethanolamine, and cellobiose metabolism between the chromosomal and plasmid-borne cpe-carrying strains. These findings support a ubiquitous occurrence of the plasmid-borne cpe-positive strains and their adaptation to the mammalian intestine, whereas the chromosomal cpe-positive strains appear to have a narrow niche in environments containing degrading plant material. Thus the epidemiology of the food poisonings caused by two populations appears different, the plasmid-borne cpe-positive strains probably contaminating foods via humans and the chromosomal strains being connected to plant material.
  • Tirkkonen, Taneli; Pakarinen, Jaakko; Rintala, Elina; Ali-Vehmas, Terhi; Marttila, Harri; Peltoniemi, Olli A. T.; Makinen, Johanna (2010)
  • Castel, Guillaume; Couteaudier, Mathilde; Sauvage, Frank; Pons, Jean-Baptiste; Murri, Severine; Plyusnina, Angelina; Pontier, Dominique; Cosson, Jean-Francois; Plyusnin, Alexander; Marianneau, Philippe; Tordo, Noel (2015)
    Puumala virus (PUUV) is the agent of nephropathia epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS) in Europe. NE incidence presents a high spatial variation throughout France, while the geographical distribution of the wild reservoir of PUUV, the bank vole, is rather continuous. A missing piece of the puzzle is the current distribution and the genetic variation of PUUV in France, which has been overlooked until now and remains poorly understood. During a population survey, from 2008 to 2011, bank voles were trapped in eight different forests of France located in areas known to be endemic for NE or in area from where no NE case has been reported until now. Bank voles were tested for immunoglobulin (Ig)G ELISA serology and two seropositive animals for each of three different areas (Ardennes, Jura and Orleans) were then subjected to laboratory analyses in order to sequence the whole S, M and L segments of PUUV. Phylogenetic analyses revealed that French PUUV isolates globally belong to the central European (CE) lineage although isolates from Ardennes are clearly distinct from those in Jura and Orleans, suggesting a different evolutionary history and origin of PUUV introduction in France. Sequence analyses revealed specific amino acid signatures along the N protein, including in PUUV from the Orleans region from where NE in humans has never been reported. The relevance of these mutations in term of pathophysiology is discussed.
  • Jouhten, Hanne; Ronkainen, Aki; Aakko, Juhani; Salminen, Seppo; Mattila, Eero; Arkkila, Perttu; Satokari, Reetta (2020)
    Fecal microbiota transplantation (FMT) is an effective treatment for recurrentClostridioides difficileinfection (rCDI) and it's also considered for treating other indications. Metagenomic studies have indicated that commensal donor bacteria may colonize FMT recipients, but cultivation has not been employed to verify strain-level colonization. We combined molecular profiling ofBifidobacteriumpopulations with cultivation, molecular typing, and whole genome sequencing (WGS) to isolate and identify strains that were transferred from donors to recipients. SeveralBifidobacteriumstrains from two donors were recovered from 13 recipients during the 1-year follow-up period after FMT. The strain identities were confirmed by WGS and comparative genomics. Our results show that specific donor-derived bifidobacteria can colonize rCDI patients for at least 1 year, and thus FMT may have long-term consequences for the recipient's microbiota and health. Conceptually, we demonstrate that FMT trials combined with microbial profiling can be used as a platform for discovering and isolating commensal strains with proven colonization capacity for potential therapeutic use.
  • Friman, Mari Johanna; Eklund, Marjut Hannele; Pitkälä, Anna Helena; Rajala-Schultz, Päivi Johanna; Rantala, Merja Hilma Johanna (2019)
    Background Infection with Serratia spp. have been associated with mastitis outbreaks in dairy cattle herds. Environmental contamination or a point source, like a teat dip product, have often been observed to be potential sources of such outbreaks. We describe two Serratia marcescens associated mastitis outbreaks associated with a contaminated teat dip containing a tertiary alkyl amine, n,n-bis (3-aminopropyl) dodecylamine in two dairy cattle farms in Finland. S. marcescens strains isolated from milk and environmental samples were identified by the MALDI-TOF method. Results Six specimens (n = 19) on Herd 1 and all specimens (n = 9) on Herd 2 were positive for S. marcescens. Positive specimens were from mastitis milk and teat dip liquid and equipment. Bacteria were not isolated from the unopened teat dip canister. The same clone of S. marcescens was isolated from milk samples and teat dip samples within the farms. Pulsed field gel electrophoresis results to the S. marcescens isolates from these two different herds were tested with unweighted pair-group method using arithmetic average clustering analysis. The isolates were not same clone in both herds, because similarity in that test was only 75% when cut-off value to similarity is 85%. Conclusions Our investigation showed that the post milking teat dip and/or temporary containers were contaminated with S. marcescens and these were most likely the sources for new mastitis cases. The negative result from the unopened teat dip canister and positive results from refillable containers demonstrated that the product itself was not contaminated with S. marcescens at the production unit, but became contaminated at the farm level.
  • Jokelainen, P.; Murat, J-B.; Nielsen, H. V. (2018)
    Genetic variation within Toxoplasma gondii can have both clinical and epidemiological significance, while the genotypes circulating in many parts of the world, including the Nordic country Denmark, are still unknown. We genetically characterized T. gondii strains that had been detected in human clinical samples in Denmark in 2011-2016. Samples that had tested positive for T. gondii DNA and had a quantification cycle value <33 were included in this study and subjected to direct genetic characterization of T. gondii based on length-polymorphism of 15 microsatellite markers. A total of 23 DNA samples from 22 individual patients were analyzed. The results were consistent with genotype II with 15/15 markers amplified from seven samples from the central nervous system (CNS) including two samples from one patient, four ocular samples, and one unspecified sample; with genotype III with 15/15 markers amplified from two ocular samples; with genotype Africa 1 with 15/15 markers amplified from one amniotic fluid sample and from one CNS-sample; with atypical genotype with 15/15 markers amplified from one CNS-sample and with 11/15 markers amplified from one CNS-sample; and with HG12-like genotype with 9/15 markers amplified from one CNS-sample. Genotype II, which is endemic in Europe, was predominant, but more than a third of the successfully genotyped strains were non-type-II. The possibility that clinical toxoplasmosis is caused by a strain that is not considered endemic to the region is definitely not negligible.
  • Aserse, Aregu Amsalu; Woyke, Tanja; Kyrpides, Nikos C.; Whitman, William B.; Lindstrom, Kristina (2017)
    The type strain of the prospective Bradyrhizobium shewense sp. nov. ERR11(T), was isolated from a nodule of the leguminous tree Erythrina brucei native to Ethiopia. The type strain Bradyrhizobium yuanmingense CCBAU 10071(T), was isolated from the nodules of Lespedeza cuneata in Beijing, China. The genomes of ERR11(T) and CCBAU 10071(T) were sequenced by DOE-JGI and deposited at the DOE-JGI genome portal as well as at the European Nucleotide Archive. The genome of ERR11(T) is 9,163,226 bp in length and has 102 scaffolds, containing 8548 protein-coding and 86 RNA genes. The CCBAU 10071(T) genome is arranged in 108 scaffolds and consists of 8,201,522 bp long and 7776 protein-coding and 85 RNA genes. Both genomes contain symbiotic genes, which are homologous to the genes found in the complete genome sequence of Bradyrhizobium diazoefficiens USDA110(T). The genes encoding for nodulation and nitrogen fixation in ERR11(T) showed high sequence similarity with homologous genes found in the draft genome of peanut-nodulating Bradyrhizobium arachidis LMG 26795(T). The nodulation genes nolYAnodD2D1YABCSUIJ-nolO-nodZ of ERR11(T) and CCBAU 10071(T) are organized in a similar way to the homologous genes identified in the genomes of USDA110(T), Bradyrhizobium ottawaense USDA 4 and Bradyrhizobium liaoningense CCBAU 05525. The genomes harbor hupSLCFHK and hypBFDE genes that code the expression of hydrogenase, an enzyme that helps rhizobia to uptake hydrogen released by the N2-fixation process and genes encoding denitrification functions napEDABC and norCBQD for nitrate and nitric oxide reduction, respectively. The genome of ERR11(T) also contains nosRZDFYLX genes encoding nitrous oxide reductase. Based on multilocus sequence analysis of housekeeping genes, the novel species, which contains eight strains formed a unique group close to the B. ottawaense branch. Genome Average Nucleotide Identity (ANI) calculated between the genome sequences of ERR11(T) and closely related sequences revealed that strains belonging to B. ottawaense branch (USDA4 and CCBAU15615), were the closest strains to the strain ERR11(T) with 95.2% ANI. Type strain ERR11(T) showed the highest DDH predicted value with CCBAU15615 (58.5%), followed by USDA 4 (53.1%). Nevertheless, the ANI and DDH values obtained between ERR11(T) and CCBAU 15615 or USDA 4 were below the cutoff values (ANI = 96.5%; DDH = 70%) for strains belonging to the same species, suggesting that ERR11(T) is a new species. Therefore, based on the phylogenetic analysis, ANI and DDH values, we formally propose the creation of B. shewense sp. nov. with strain ERR11(T) (HAMBI 3532(T)= LMG 30162(T)) as the type strain.
  • Marjonen, Heidi; Toivonen, Mia; Lahti, Laura; Kaminen-Ahola, Nina (2018)
    Prenatal alcohol exposure (PAE) can harm the embryonic development and cause life-long consequences in offspring's health. To clarify the molecular mechanisms of PAE we have used a mouse model of early alcohol exposure, which is based on maternal ad libitum ingestion of 10% (v/v) ethanol for the first eight days of gestation (GD 0.5-8.5). Owing to the detected postnatal growth-restricted phenotype in the offspring of this mouse model and both prenatal and postnatal growth restriction in alcohol-exposed humans, we focused on imprinted genes Insulin-like growth factor 2 (Igf2), H19, Small Nuclear Ribonucleoprotein Polypeptide N (Snrpn) and Paternally expressed gene 3 (Peg3), which all are known to be involved in embryonic and placental growth and development. We studied the effects of alcohol on DNA methylation level at the Igf2/H19 imprinting control region (ICR), Igf2 differentially methylated region 1, Snrpn ICR and Peg3 ICR in 9.5 embryonic days old (E9.5) embryos and placentas by using MassARRAY EpiTYPER. To determine alcohol-induced alterations globally, we also examined methylation in long interspersed nuclear elements (Line-1) in E9.5 placentas. We did not observe any significant alcohol-induced changes in DNA methylation levels. We explored effects of PAE on gene expression of E9.5 embryos as well as E9.5 and E16.5 placentas by using quantitative PCR. The expression of growth promoter gene Igf2 was decreased in the alcohol-exposed E9.5 and E16.5 placentas. The expression of negative growth controller H19 was significantly increased in the alcohol exposed E9.5 embryos compared to controls, and conversely, a trend of decreased expression in alcohol-exposed E9.5 and E16.5 placentas were observed. Furthermore, increased Snrpn expression in alcohol-exposed E9.5 embryos was also detected. Our study indicates that albeit no alterations in the DNA methylation levels of studied sequences were detected by EpiTYPER, early PAE can affect the expression of imprinted genes in both developing embryo and placenta.
  • Feng, Yuan; Stams, Alfons J. M.; Anchez-Andrea, Irene S.; de Vos, Willem M. (2018)
    A novel anaerobic, non-spore-forming bacterium was isolated from a faecal sample of a healthy adult. The isolate, designated strain YIT, was cultured in a basal liquid medium under a gas phase of H-2/CO2 supplemented with yeast extract (0.1 g l(-1)). Cells of strain YIT were short rods (0.4-0.7 x 2.0-2.5 mu m), appearing singly or in pairs, and stained Gram-positive. Catalase activity and gelatin hydrolysis were positive while oxidase activity, indole formation, urease activity and aesculin hydrolysis were negative. Growth was observed within a temperature range of 20-45 degrees C (optimum, 35-37 degrees C), and a pH range of 5.0-8.0 (optimum pH 7.0-7.5). Doubling time was 2.3 h when grown with glucose at pH 7.2 and 37 degrees C. Besides acetogenic growth, the isolate was able to ferment a large range of monomeric sugars with acetate and butyrate as the main end products. Strain YIT did not show respiratory growth with sulfate, sulfite, thiosulfate or nitrate as electron acceptors. The major cellular fatty acids of the isolate were C-16:0 and C-18:0. The genomic DNA G+C content was 47.8 mol%. Strain YIT is affiliated to the genus Eubacterium, sharing highest levels of 16S rRNA gene similarity with Eubacterium limosum ATCC 8486(T) (97.3 %), Eubacterium callanderi DSM 3662(T) (97.5 %), Eubacterium aggregans DSM 12183(T) (94.4 %) and Eubacterium barkeri DSM 1223(T) (94.8 %). Considering its physiological and phylogenetic characteristics, strain YIT represents a novel species within the genus Eubacterium, for which the name Eubacterium maltosivorans sp. nov. is proposed. The type strain is YIT (= DSM 105863(T) = JCM 32297(T)).
  • Hussain, Nazar; Tariq, Muhammad; Saris, Per Erik Joakim; Zaidi, Arsalan (2021)
    Introduction: Probiotic and postbiotic potential of thirty-two strains of lactic acid bacteria (LAB), obtained earlier from artisanal dairy sources in Pakistan, have been investigated against major multi-drug resistant (MDR) and food borne pathogenic bacteria. Methodology: LAB strains were identified by 16S rRNA gene sequencing and their antibacterial activity was assessed by the microdilution method. Four LAB isolates, Weissella confusa PL6, Enterococcus faecium PL7, and Lactobacillus delbrueckii PL11 and PL13 were shortlisted. Their ability to degrade lactose and safety for human consumption in terms of hemolysis and antibiotic susceptibility were assessed in vitro. The antibacterial components in the cell-free supernatants (CFSs) of isolate cultures were characterized biochemically by HPLC. Results: Acid neutralization but not protease treatment abolished the antibacterial activity of CFSs. Lactic, acetic and propionic acids were the main acids in the CFSs, and acid production peaked in the stationary phase of growth. The antibacterial activity of the LAB cultures resulted from secretion of organic acids that lowered the pH. The strains exhibited variable ability to degrade lactose and were non-hemolytic and susceptible to the most common antibiotics. Conclusions: These LAB strains are probiotic candidates for further investigation of their postbiotic role in naturally preserving processed foods and for attenuation of lactose intolerance.
  • Luukinen, Bruno Vincent; Vuento, Risto; Hirvonen, Jari Juhani (2019)
    Today, there are numerous different molecular diagnostic assays for the detection of tuberculosis (TB), allowing the optimization of rapid detection of TB according to the clinical need. In this study, two high-throughput TB PCR assays with combined antimicrobial resistance detection, Anyplex (TM) II MTB/MDR (Seegene) and RealTime MTB + RealTime MTB RIF/INH Resistance (Abbott Molecular), were evaluated for routine use in a clinical setting of low population and low TB prevalence in Finland. The RealTime MTB assay was 100% concordant (22/22 positive, n = 169) with the reference methods (culture and Xpert MTB/RIF PCR assay, Cepheid). However, with a limitation of four separate PCR cycles per kit, the routine use in a low TB-prevalence setting would easily lead to wasting most of the RIF/INH Resistance reagents. The Anyplex (TM) II MTB/MDR assay usability was more adaptive to suit the clinical setting but the assay sensitivity was considerably lower (86%, 19/22 positive, n = 76) being closer to the sensitivity of smear microscopy. The findings of this study suggest that the evaluated high-throughput MTB/MDR assays are evidently suboptimal for routine use in a low population, low TB-prevalence setting. In addition, neither of the two assays covers non-tuberculous mycobacteria and could therefore not fully replace acid-fast staining as the initial screening method.
  • Zou, Lan; Chen, Yuan Xue; Penttinen, Petri; Lan, Qin; Wang, Ke; Liu, Ming; Peng, Dan; Zhang, Xiaoping; Chen, Qiang; Zhao, Ke; Zeng, Xiangzhong; Xu, Kai Wei (2016)
    Thirty-one nodulating rhizobium strains were collected from root nodules of spring and winter type faba bean cultivars grown in micro ecoarea, i.e. the same field in Chengdu plain, China. The symbiotic efficiency and phylogeny of these strains were studied. Effectively nitrogen fixing strains were isolated from both winter type and spring type cultivars. Based on phylogenetic analysis of 16S rRNA gene and concatenated sequence of atpD, glnII and recA genes, the isolates were assigned as Rhizobium anhuiense and a potential new Rhizobium species. The isolates were diverse on symbiosis related gene level, carrying five, four and three variants of nifH, nodC and nodD, respectively. Strains carrying similar gene combinations were trapped by both winter and spring cultivars, disagreeing with the specificity of symbiotic genotypes to reported earlier faba bean ecotypes.