RESUMO
Two strains of a Gram-staining-positive species were isolated from German bulk tank milk. On the basis of their 16S rRNA sequences they were affiliated to the genus Facklamia but could not be assigned to any species with a validly published name. Facklamia miroungae ATCC BAA-466T (97.3â% 16S rRNA sequence similarity), Facklamia languida CCUG 37842T (96.9â%), and Facklamia hominis CCUG 36813T (96.6â%) are the closest relatives. In the 16S rRNA phylogeny and in the core-genome phylogeny strains WS 5301T and WS 5302 form a well-supported, separate lineage. Pairwise average nucleotide identity calculated using MUMmer (ANIm) between WS 5301T and type strains of other Facklamia species is well below the species cut-off (95â%) and ranges from 83.4 to 87.7â%. The DNA G+C content of the type strain is 36.4 mol% and the assembly size of the genome is 2.2 Mb. Cells of WS 5301T are non-motile, non-endospore-forming, oxidase-negative, catalase-negative and facultatively anaerobic cocci. The fastidious species grows at 10-40 °C and with up to 7.0â% (w/v) NaCl in BHI supplemented with 5 g l-1 yeast extract. Major polar lipids are phosphatidylglycerol, diphosphatidylglycerol and two glycolipids. Predominant fatty acids are C16â:â1ω9c and C18â:â1ω9c. On the basis of their genomic, physiological and chemotaxonomic characteristics the strains examined in this study represent the same, hitherto unknown species. We propose the name Facklamia lactis sp. nov. for which WS 5301T (=DSM 111018T=LMG 31861T) is the type strain and WS 5302 (=DSM 111019=LMG 31862) is an additional strain of this novel species.
Assuntos
Aerococcaceae/classificação , Leite/microbiologia , Filogenia , Aerococcaceae/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Alemanha , Glicolipídeos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
During a study investigating the microbiota of raw milk and its semi-finished products, strains WS 5106T and WS 5096 were isolated from cream and skimmed milk concentrate. They could be assigned to the genus Pseudomonas by their 16S rRNA sequences, but not to any validly named species. In this work, a polyphasic approach was used to characterize the novel strains and to investigate their taxonomic status. Examinations based on the topology of core genome phylogenomy as well as average nucleotide identity (ANIm) comparisons suggested a novel Pseudomonas species within the Pseudomonas fluorescens subgroup. With pairwise ANIm values of 90.1 and 89.8â%, WS 5106T was most closely related to Pseudomonas nabeulensis CECT 9765T and Pseudomonas kairouanensis CECT 9766T. The G+C content of strain WS 5106T was 60.1 mol%. Morphologic analyses revealed Gram-stain-negative, aerobic, catalase and oxidase positive, rod-shaped and motile cells. Proteolysis on skimmed milk agar as well as lipolysis on tributyrin agar occurred at both 28 and 6 °C. Tolerated growth conditions were temperatures between 4 and 34 °C, pH values between 6.0 and 8.0, and salt concentrations of up to 5â%. Fatty acid profiles showed a pattern typical for Pseudomonas, with C16â:â0 as the dominant component. The major cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol and the dominating quinone was Q-9. Based on these results, it is proposed to classify the strains as a novel species, Pseudomonas cremoris sp. nov., with WS 5106T (=DSM 111143T=LMG 31863T) as type strain and WS 5096 (=DSM 111129=LMG 31864) as an additional strain.
Assuntos
Leite/microbiologia , Filogenia , Pseudomonas/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Alemanha , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Proteólise , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/químicaRESUMO
The heat-stable peptidase AprX, secreted by psychrotolerant Pseudomonas species in raw milk, is a major cause of destabilization and premature spoilage of ultra-high temperature (UHT) milk and milk products. To enable rapid detection and quantification of seven frequent and proteolytic Pseudomonas species (P. proteolytica, P. gessardii, P. lactis, P. fluorescens, P. protegens, P. lundensis, and P. fragi) in raw milk, we developed two triplex qPCR assays taking into account species-dependent differences in AprX activity. Besides five species-specific hydrolysis probes, targeting the aprX gene, a universal rpoB probe was included in the assay to determine the total Pseudomonas counts. For all six probes, linear regression lines between Cq value and target DNA concentration were obtained in singleplex as well as in multiplex approaches, yielding R2 values of > 0.975 and amplification efficiencies of 85-97%. Moreover, high specificity was determined using genomic DNA of 75 Pseudomonas strains, assigned to 57 species, and 40 other bacterial species as templates in the qPCR. Quantification of the target species and total Pseudomonas counts resulted in linear detection ranges of approx. 103-107 cfu/ml, which correspond well to common Pseudomonas counts in raw milk. Application of the assay using 60 raw milk samples from different dairies showed good agreement of total Pseudomonas counts calculated by qPCR with cell counts derived from cultivation. Furthermore, a remarkably high variability regarding the species composition was observed for each milk sample, whereby P. lundensis and P. proteolytica/P. gessardii were the predominant species detected. KEY POINTS: ⢠Multiplex qPCR for quantification of seven proteolytic Pseudomonas species and total Pseudomonas counts in raw milk ⢠High specificity and sensitivity via hydrolysis probes against aprX and rpoB ⢠Rapid method to determine Pseudomonas contamination in raw milk and predict spoilage potential.
Assuntos
Leite , Pseudomonas , Animais , Temperatura Alta , Leite/metabolismo , Peptídeo Hidrolases/metabolismo , Proteólise , Pseudomonas/genética , Pseudomonas/metabolismoRESUMO
The highly complex raw milk matrix challenges the sample preparation for amplicon-sequencing due to low bacterial counts and high amounts of eukaryotic DNA originating from the cow. In this study, we optimized the extraction of bacterial DNA from raw milk for microbiome analysis and evaluated the impact of cycle numbers in the library-PCR. The selective lysis of eukaryotic cells by proteinase K and digestion of released DNA before bacterial lysis resulted in a high reduction of mostly eukaryotic DNA and increased the proportion of bacterial DNA. Comparative microbiome analysis showed that a combined enzymatic and mechanical lysis procedure using the DNeasy® PowerFood® Microbial Kit with a modified protocol was best suitable to achieve high DNA quantities after library-PCR and broad coverage of detected bacterial biodiversity. Increasing cycle numbers during library-PCR systematically altered results for species and beta-diversity with a tendency to overrepresentation or underrepresentation of particular taxa. To limit PCR bias, high cycle numbers should thus be avoided. An optimized DNA extraction yielding sufficient bacterial DNA and enabling higher PCR efficiency is fundamental for successful library preparation. We suggest that a protocol using ethylenediaminetetraacetic acid (EDTA) to resolve casein micelles, selective lysis of somatic cells, extraction of bacterial DNA with a combination of mechanical and enzymatic lysis, and restriction of PCR cycles for analysis of raw milk microbiomes is optimal even for samples with low bacterial numbers. KEY POINTS: ⢠Sample preparation for high-throughput 16S rRNA gene sequencing of raw milk microbiota. ⢠Reduction of eukaryotic DNA by enzymatic digestion. ⢠Shift of detected microbiome caused by high cycle numbers in library-PCR.
Assuntos
Microbiota , Leite , Animais , Bovinos , DNA Bacteriano/genética , Feminino , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genéticaRESUMO
A polyphasic approach was used to investigate the taxonomic status of two bacterial strains, WS 5072T and WS 5092, isolated from skimmed milk concentrate and raw cow's milk. The 16S rRNA and rpoD gene sequences affiliated the strains to the same, hitherto unknown, Pseudomonas species. Further examinations of the draft genomes based on multilocus sequence analysis and average nucleotide identity confirmed the presence of a novel Pseudomonas species. It was most closely related to Pseudomonas fragi DSM 3456T with 86.3â% ANIm. The DNA G+C content of strain WS 5072T was 56.3 mol%. Cells were aerobic, Gram-negative, catalase and oxidase positive, rod-shaped and motile. Growth occurred at 4-34 °C, pH 5.5-8.0 and with salt concentrations of up to 7â%. The major cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The dominating quinone was Q-9 with 94 %, with noticeable amounts of Q-8 (5 %) and traces of Q-7 and Q-10. Fatty acid profiles showed a composition common for Pseudomonas with the major component C16â:â0. Based on these results, the novel species Pseudomonas saxonica sp. nov. is proposed, with the type strain WS 5072T (=DSM 108989T=LMG 31234T) and the additional strain WS 5092 (=DSM 108990=LMG 31235).
Assuntos
Microbiologia de Alimentos , Leite/microbiologia , Filogenia , Pseudomonas/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Genes Bacterianos , Alemanha , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pseudomonas/isolamento & purificação , Quinonas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Three strains of a Gram-stain-positive, catalase-negative, facultative anaerobic, and coccoid species were isolated from German bulk tank milk. Phylogenetic analyses based on the 16S rRNA gene sequences indicated that the three strains (WS4937T, WS4759 and WS5303) constitute an independent phylogenetic lineage within the family Aerococcaceae with Facklamia hominis CCUG 36813T (93.7-94.1â%) and Eremococcus coleocola M1831/95/2T (93.5â%) as most closely related type species. The unclassified strains demonstrated variable growth with 6.5â% (w/v) NaCl and tolerated pH 6.5-9.5. Growth was observed from 12 to 39 °C. Their cell-wall peptidoglycan belongs to the A1α type (l-Lys-direct) consisting of alanine, glutamic acid and lysine. The predominant fatty acids were C16â:â1 ω9c, C16â:â0 and C18â:â1 ω9c and in the polar lipids profile three glycolipids, a phospholipid, phosphatidylglycerol, phosphoglycolipid and diphosphatidylglycerol were found. The G+C content of strain WS4937T was 37.4 mol% with a genome size of ~3.0 Mb. Based on phylogenetic, phylogenomic and biochemical characterizations, the isolates can be demarcated from all other genera of the family Aerococcaceae and, therefore, the novel genus Fundicoccus gen. nov. is proposed. The type species of the novel genus is Fundicoccus ignavus gen. nov., sp. nov. WS4937T (=DSM 109652T=LMG 31441T).
Assuntos
Aerococcaceae/classificação , Leite/microbiologia , Filogenia , Aerococcaceae/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Two strains, WS 5063T and WS 5067, isolated from raw cow's milk and skimmed milk concentrate, could be affiliated as members of the same, hitherto unknown, Pseudomonas species by 16S rRNA and rpoD gene sequences. Multilocus sequence and average nucleotide identity (ANIm) analyses based on draft genome sequences confirmed the discovery of a novel Pseudomonas species. It was most closely related to Pseudomonas synxantha DSM 18928T with an ANIm of 91.4â%. The DNA G+C content of WS 5063T was 60.0 molâ%. Phenotypic characterizations showed that the isolates are rod-shaped, motile, catalase- and oxidase-positive, and aerobic. Growth occurred at 4-34 °C and at pH values of pH 5.5-8.0. Both strains showed strong ß-haemolysis on blood agar. The major cellular polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The dominant quinone was Q-9 (90â%), but noticeable amounts of Q-8 (9â%) and traces of Q-7 were also detected. Fatty acid profiles were typical for Pseudomonas species and exhibited C16â:â0 as a major component. Based on these results, we conclude that both strains belong to a novel species, for which the name Pseudomonas haemolytica sp. nov. is proposed. The type strain is WS 5063T (=DSM 108987T=LMG 31232T) and an additional strain is WS 5067 (=DSM 108988=LMG 31233).
Assuntos
Microbiologia de Alimentos , Leite/microbiologia , Filogenia , Pseudomonas/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
Eight facultatively anaerobic rod-shaped bacteria were isolated from raw milk and two other dairy products. Results of phylogenetic analyses based on 16S rRNA gene sequences showed that the isolates are placed in a distinct lineage within the family Propionibacteriaceae with Propioniciclava sinopodophylli and Propioniciclava tarda as the closest relatives (94.6 and 93.5â% similarity, respectively). The cell-wall peptidoglycan contained meso-diaminopimelic acid, alanine and glutamic acid and was of the A1γ type (meso-DAP-direct). The major cellular fatty acid was anteiso-C15â:â0 and the major polar lipids were diphosphatidylglycerol, phosphatidyglycerol and three unidentified glycolipids. The quinone system contained predominantly menaquinone MK-9(H4). The G+C content of the genomic DNA of strain VG341T was 67.7 mol%. The whole-cell sugar pattern contained ribose, rhamnose, arabinose and galactose. On the basis of phenotypic and genetic data, eight strains (VG341T, WS4684, WS4769, WS 4882, WS4883, WS4901, WS4902 and WS4904) are proposed to be classified as members of a novel species in a new genus of the family Propionibacteriaceae, for which the name Brevilactibacter flavus gen. nov., sp. nov. is proposed. The type strain is VG341T (=WS4900T=DSM 100885T=LMG 29089T) and seven additional strains are WS4684, WS4769, WS4882, WS4883, WS4901, WS4902 and WS4904. Furthermore, we propose the reclassification of P. sinopodophylli as Brevilactibacter sinopodophylli comb. nov.
Assuntos
Laticínios/microbiologia , Leite/microbiologia , Filogenia , Propionibacteriaceae/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Microbiologia de Alimentos , Alemanha , Glicolipídeos/química , Peptidoglicano/química , Fosfolipídeos/química , Propionibacteriaceae/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
The occurrence of thermophilic spore formers in dairy powders is a major concern for producers worldwide. This study aims to investigate the resistance of thermophilic endospores towards cleaning solutions typically used for cleaning-in-place in dairy manufacturing plants. From eleven tested strains, all were able to survive an alkaline treatment (NaOH) at 65⯰C for 10â¯min (0.5%), whereas at concentrations of 2% eight strains withstood the treatment. Acid solutions were more sporicidal. At 0.5% of HNO3, only three strains survived the treatment. Milk impurities reduced the inactivation effect of the NaOH solutions towards thermophilic spore formers. For two selected strains, a detailed kinetic inactivation in NaOH and HNO3 solutions at different temperatures was performed and non-log-linear inactivation curves were observed. This study highlights the risk of reusing cleaning solutions in dairies.
Assuntos
Ácidos/farmacologia , Álcalis/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Leite/microbiologia , Esporos Bacterianos/efeitos dos fármacos , Temperatura , Animais , Contagem de Colônia Microbiana , Indústria de Laticínios , Farmacorresistência Bacteriana , Concentração de Íons de Hidrogênio , Cinética , Pós , Proteínas do Soro do Leite/metabolismoRESUMO
A Gram-stain-negative, rod-shaped Proteobacteria isolate, MBT G8648T, was obtained from an acid curd cheese called Quargel. The isolate was moderately salt tolerant and motile, with numerous peritrichous flagella. The 16S rRNA gene sequence analysis indicated that the strain belongs to the genus Halomonas, with 98.42â% 16S rRNA gene sequence similarity with Halomonas titanicae BH1T as nearest related neighbour. Further comparative sequence analysis of secA and gyrB genes, as well as physiological and biochemical tests, revealed that this bacterium formed a taxon well-separated from its nearest neighbours and other established Halomonas species. Thus, the strain represents a new species, for which the name Halomonas nigrificans sp. nov. is proposed, with strain MBT G8648T (=LMG 29097T =DSM 105749T) as type strain.
Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Halomonas/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Europa (Continente) , Genes Bacterianos , Halomonas/genética , Halomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Psychrotrophic gram-negative Pseudomonas spp. represent a serious problem in the dairy industry as they can cause spoilage of milk and dairy products. Bacteriophages have moved into focus as promising biocontrol agents for such food spoilage bacteria. The virulent Siphoviridae phage PMBT14 was isolated on a mutant variant of P. fluorescens DSM 50090 challenged with an unrelated virulent P. fluorescens DSM 50090 Podoviridae phage (i.e., mutant strain DSM 50090R). PMBT14 has a 47,820-bp dsDNA genome with 76 predicted open reading frames (ORFs). Its genome shows no significant sequence similarity to that of known phages, suggesting that PMBT14 represents a novel phage. Phage PMBT14 could be a promising biocontrol agent for P. fluorescens in milk or dairy foods.
Assuntos
Genoma Viral , Lisogenia/fisiologia , Fagos de Pseudomonas/genética , Pseudomonas fluorescens/virologia , Siphoviridae/genética , Proteínas Virais/genética , Agentes de Controle Biológico , Mapeamento Cromossômico , DNA/genética , DNA/metabolismo , DNA Viral/genética , DNA Viral/metabolismo , Laticínios/microbiologia , Microbiologia de Alimentos , Ontologia Genética , Tamanho do Genoma , Humanos , Anotação de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Fagos de Pseudomonas/classificação , Fagos de Pseudomonas/patogenicidade , Fagos de Pseudomonas/ultraestrutura , Análise de Sequência de DNA , Siphoviridae/classificação , Siphoviridae/metabolismo , Proteínas Virais/metabolismoRESUMO
A Gram-stain-positive, non-motile, rod-shaped bacterium, designated TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T), was isolated from spoiled beer. This bacterium did not form spores, and was catalase-negative and facultatively anaerobic. Its taxonomic position was determined in a polyphasic study. The 16S rRNA gene sequence similarity data showed that the strain belonged to the Lactobacillus genus with the nearest neighbours being Lactobacillus koreensis DCY50T (sequence similarity 99.5â%), Lactobacillus yonginensis THK-V8T (99.2â%) and Lactobacillus parabrevis LMG 11984T (98.7â%). Sequence comparisons of additional phylogenetic markers, pheS and rpoA, confirmed the 16S rRNA gene sequence tree topology. The maximum rpoA sequence similarity was 92.3â% with L. yonginensis THK-V8T. The DNA G+C content of the isolate was 50.0 mol%. The DNA-DNA relatedness showed that strain TUM BP 140423000-2250T could be clearly distinguished from L. koreensis DCY 50T (30.8±0.4â%) and L. yonginensis THK-V8T (23.6±5.9â%). The major fatty acids were C18â:â1ω9c, summed feature 7 (comprised of C19â:â0 cyclo ω10c/C19â:â1ω6c) and C16â:â0. Based on phenotypic and genotypic studies, the authors propose classifying the new isolate as a representative of a novel species of the genus Lactobacillus, Lactobacillus cerevisiae sp. nov. The type strain is deposited at the Research Centre Weihenstephan for Brewing and Food Quality as TUM BP 140423000-2250T (=DSM 100836T=LMG 29073T).
Assuntos
Cerveja/microbiologia , Lactobacillus/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Alemanha , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Five strains, designated WS 4672T, WS 4998, WS 4992T, WS 4997 and WS 5000, isolated from bovine raw milk formed two individual groups in a phylogenetic analysis. The most similar species on the basis of 16S rRNA gene sequences were Pseudomonas azotoformans IAM 1603T, Pseudomonas gessardii CIP 105469T and Pseudomonas libanensis CIP 105460T showing 99.7-99.6â% similarity. Using rpoD gene sequences Pseudomonas veronii LMG 17761T (93.3â%) was most closely related to strain WS 4672T and Pseudomonas libanensis CIP 105460T to strain WS 4992T (93.3â%). The five strains could be differentiated from their closest relatives and from each other by phenotypic and chemotaxonomic characterization and ANIb values calculated from draft genome assemblies. ANIb values of strains WS 4992T and WS4671T to the closest relatives are lower than 90â%. The major cellular polar lipids of both strains are phosphatidylethanolamine, phosphatidylglycerol, a phospholipid and diphosphatidylglycerol, and their major quinone is Q-9. The DNA G+C content of strains WS 4992T and WS 4672T were 60.0â and 59.7â mol%, respectively. Based on these genotypic and phenotypic traits two novel species of the genus Pseudomonas are proposed: Pseudomonas lactis sp. nov. [with type strain WS 4992T (=DSM 29167T=LMG 28435T) and the additional strains WS 4997 and WS 5000], and Pseudomonasparalactis sp. nov. [with type strain WS 4672T (=DSM 29164T=LMG 28439T) and additional strain WS 4998].
Assuntos
Leite/microbiologia , Filogenia , Pseudomonas/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Pseudomonas/genética , Pseudomonas/isolamento & purificação , Quinonas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
A survey of the psychrotolerant yeast microbiota of vacuum-packed beef was conducted between 2010 and 2012. Chilled vacuum-packed beef (n = 50) sampled from 15 different producers was found to have a mean psychrotolerant yeast count of 3.76 log cfu per cm(2). During this assessment, a recently described yeast named Kazachstania psychrophila was shown to be associated with this product. In order to gain basic knowledge about the spoilage potential of K. psychrophila in vacuum-packed beef, challenge studies were performed and the survival of three different K. psychrophila strains was analyzed during storage of artificially contaminated beef. Beef samples were inoculated with the yeasts at a contamination level of 2 log cfu per cm(2). Survival and growth of K. psychrophila strains was monitored on malt extract agar at regular intervals over 84 days. Kazachstania levels rapidly increased about 5 log units within 16 days under chill conditions (4 °C). Gas bubbles were observed after 16 days, while discoloration and production of off-flavors became evident after 42 days in inoculated samples. This study demonstrates for the first time, that the psychrotolerant yeast K. psychrophila is a dominant spoilage microorganism of vacuum-packed beef products stored at low temperatures, causing sensory defects which result in reduced shelf life, and consequently in considerable economic losses.
Assuntos
Contaminação de Alimentos/análise , Carne/microbiologia , Leveduras/crescimento & desenvolvimento , Animais , Bovinos , Contagem de Colônia Microbiana , Embalagem de Alimentos , Carne/análise , VácuoRESUMO
Three strains of an anaerobic, Gram-stain-positive coccobacillus were isolated from the intestines of mice. These strains shared 100â% similarity in their 16S rRNA gene sequences, but were distantly related to any described members of the family Lachnospiraceae (<94â%). The most closely related species with names that have standing in nomenclature were Robinsoniella peoriensis, Ruminococcus gnavus, Blautia producta and Clostridium xylanolyticum. Phylogenetic relationships based on 16S rRNA gene sequence analysis were confirmed by partial sequencing of hsp60 genes. The use of an in-house database search pipeline revealed that the new isolates are most prevalent in bovine gut samples when compared with human and mouse samples for Ruminococcus gnavus and B. producta. All three isolated strains shared similar cellular fatty acid patterns dominated by C16â:â0 methyl ester. Differences in the proportions of C12â:â0 methyl ester, C14â:â0 methyl ester and C18â:â1 cis-11 dimethyl acetal were observed when compared with phylogenetically neighbouring species. The major short-chain fatty acid produced by strain SRB-530-5-H(T) was acetic acid. This strain tested positive for utilization of d-fructose, d-galacturonic acid, d-malic acid, l-alanyl l-threonine and l-glutamic acid but was negative for utilization of amygdalin, arbutin, α-d-glucose, 3-methyl d-glucose and salicin, in contrast to the type strain of the closest related species Robinsoniella peoriensis. The isolates were not able to use mannitol for growth. Based on genotypic, phenotypic and chemotaxonomic characteristics, we propose to create the new genus and species Murimonas intestini gen. nov., sp. nov. to accommodate the three strains SRB-530-5-H(T) (â=âDSM 26524(T)â=âCCUG 63391(T)) (the type strain of Murimonas intestini), SRB-509-4-S-H (â=âDSM 27577â=âCCUG 64595) and SRB-524-4-S-H (â=âDSM 27578â=âCCUG 64594).
Assuntos
Bactérias Anaeróbias/classificação , Bactérias Gram-Positivas/classificação , Intestinos/microbiologia , Filogenia , Animais , Bactérias Anaeróbias/genética , Bactérias Anaeróbias/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Camundongos/microbiologia , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
BACKGROUND: The routine diagnosis of Streptococcus spp. and other mastitis associated gram-positive, catalase-negative cocci is still based upon biochemical tests and serological methods, which frequently provide ambiguous identification results. We therefore aimed to establish an accurate identification system for differential diagnosis of mastitis associated Streptococcus spp. and related species using biophysical techniques such as Fourier-transform infrared (FTIR) spectroscopy and MALDI - TOF/MS. RESULTS: Based on a panel of 210 isolates from cases of bovine mastitis, an unsupervised FTIR spectral reference library was established and an artificial neural network (ANN) - assisted identification system was developed. All bacterial isolates were previously identified by species-specific PCR and/or 16S rRNA gene sequence analysis. An overall identification rate of 100% at species level for 173 strains unknown to the ANN and the library was achieved by combining ANN and the spectral database, thus demonstrating the suitability of our FTIR identification system for routine diagnosis. In addition, we investigated the potential of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of mastitis associated Streptococcus spp. and related bacteria. Using the Microflex LT System, MALDI Biotyper software™ (V3.3) we achieved an accuracy rate of 95.2%. A blind study, including 21 clinical samples from dairy cows, revealed a 100% correct species identification rate for FTIR and 90.5% for MALDI-TOF MS, indicating that these techniques are valuable tools for diagnosis. CONCLUSIONS: This study clearly demonstrates that FTIR spectroscopy as well as MALDI-TOF MS can significantly improve and facilitate the identification and differentiation of mastitis associated Streptococcus spp. and related species. Although the FTIR identification system turned out being slightly superior to MALDI-TOF MS in terms of identification on species level, both methods offer interesting alternatives to conventional methods currently used in mastitis diagnosis as both of them provide high accuracy at low operating costs once the instrument is acquired.
Assuntos
Técnicas Bacteriológicas/veterinária , Infecções por Bactérias Gram-Positivas/veterinária , Cocos Gram-Positivos/isolamento & purificação , Mastite Bovina/microbiologia , Animais , Técnicas Bacteriológicas/métodos , Bovinos , Análise por Conglomerados , Feminino , Infecções por Bactérias Gram-Positivas/diagnóstico , Infecções por Bactérias Gram-Positivas/microbiologia , Cocos Gram-Positivos/classificação , Mastite Bovina/diagnóstico , Redes Neurais de Computação , Especificidade da Espécie , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
Staphylococcus aureus capsular polysaccharides (CP) are important virulence factors and represent putative targets for vaccine development. Therefore, the purpose of this study was to develop a high-throughput method to identify and discriminate the clinically important S. aureus capsular serotypes 5, 8, and NT (nontypeable). A comprehensive set of clinical isolates derived from different origins and control strains, representative for each serotype, were used to establish a CP typing system based on Fourier transform infrared (FTIR) spectroscopy and chemometric techniques. By combining FTIR spectroscopy with artificial neuronal network (ANN) analysis, a system was successfully established, allowing a rapid identification and discrimination of all three serotypes. The overall accuracy of the ANN-assisted FTIR spectroscopy CP typing system was 96.7% for the internal validation and 98.2% for the external validation. One isolate in the internal validation and one isolate in the external validation failed in the classification procedure, but none of the isolates was incorrectly classified. The present study demonstrates that ANN-assisted FTIR spectroscopy allows a rapid and reliable discrimination of S. aureus capsular serotypes. It is suitable for diagnostic as well as large-scale epidemiologic surveillance of S. aureus capsule expression and provides useful information with respect to chronicity of infection.
Assuntos
Cápsulas Bacterianas/química , Redes Neurais de Computação , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Staphylococcus aureus/química , Staphylococcus aureus/classificação , Animais , Humanos , Sensibilidade e Especificidade , Sorotipagem/métodos , Infecções Estafilocócicas/microbiologiaRESUMO
A Gram-stain-positive, strictly aerobic, rod-shaped and weakly motile bacterium, designated WS 4627(T), was isolated from a dairy product sample collected in southern Germany. Spherical to slightly ellipsoidal endospores were formed centrally or subterminally in sometimes slightly swollen sporangia. The isolate was able to grow at 8-35 °C, at pH 6.5-8.5 and with 0.5-16.5% (w/v) NaCl. The diamino acid of the cell wall was meso-diaminopimelic acid (peptidoglycan type A1γ) and the genomic DNA G+C content was 39.1 mol%. The major menaquinone was MK-7, the cellular fatty acid profile contained major amounts of anteiso-C(15:0) and anteiso-C(17:0) and the major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. Strain WS 4627(T) was most closely related to 'Virgibacillus natachei' FarD (96.5% 16S rRNA gene sequence similarity) and 'Virgibacillus zhanjiangensis' JSM 079157 (96.0%). Based on the data presented, strain WS 4627(T) represents a novel species of the genus Virgibacillus, for which the name Virgibacillus halotolerans sp. nov. is proposed. The type strain is WS 4627(T) (â=DSM 25060(T)â=LMG 26644(T)).
Assuntos
Laticínios/microbiologia , Microbiologia de Alimentos , Filogenia , Virgibacillus/classificação , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/análise , Alemanha , Dados de Sequência Molecular , Peptidoglicano/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Esporos Bacterianos/crescimento & desenvolvimento , Virgibacillus/genética , Virgibacillus/isolamento & purificação , Vitamina K 2/análogos & derivados , Vitamina K 2/análiseRESUMO
Three Gram-reaction-positive bacteria, isolated from the air in a medical practice (strains WS4601(T), WS4602) or a pharmaceutical clean room (strain WS4599), were characterized using a polyphasic approach. Phylogenetic analyses based on 16S rRNA and recA gene sequences of the three novel strains showed that they formed a distinct lineage within the genus Micrococcus, sharing 16S rRNA gene sequence similarities of 96.1-98.0 % with other species of this genus. Chemotaxonomic features also supported the classification of the three novel strains within the genus Micrococcus. The major cellular fatty acids of strain WS4601(T) were anteiso-C(15 : 0) and iso-C(15 : 0), the cell-wall peptidoglycan was of type A3α (L-Lys-L-Ala), and the predominant respiratory quinones were MK-7(H(2)) and MK-8(H(2)). The polar lipid profile contained diphosphatidylglycerol and phosphatidylglycerol, but no phosphatidylinositol. The G+C content of the genomic DNA was 70.4 mol%. Numerous physiological properties were found that clearly distinguished strains WS4599, WS4601(T) and WS4602 from established members of the genus Micrococcus. Based on the phenotypic and phylogenetic data, strains WS4599, WS4601(T) and WS4602 are considered to represent three different strains of a novel species of the genus Micrococcus, for which the name Micrococcus cohnii sp. nov. is proposed. The type strain is WS4601(T) (=DSM 23974(T)=LMG 26183(T)).
Assuntos
Microbiologia do Ar , Micrococcus/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ambiente Controlado , Ácidos Graxos/análise , Micrococcus/genética , Micrococcus/isolamento & purificação , Dados de Sequência Molecular , Peptidoglicano/análise , Quinonas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
A gram-positive, oxidase- and catalase-positive, strictly aerobic and motile bacterium, designated WS 4626(T), was isolated from a medical practice. Spherical endospores were formed terminally in swollen rods. The genomic DNA G+C content was 37.1 mol%. Cells contained iso-C15â:â0, anteiso-C15â:â0, iso-C17â:â1ω10c, anteiso-C17â:â0 and iso-C17â:â0 as the predominant cellular fatty acids and MK-7 and MK-6 as the major isoprenoid quinones. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, the cell-wall peptidoglycan was type A4α, L-Lys-D-Asp and the major cell-wall sugar was xylose. The closest phylogenetic relatives were Lysinibacillus xylanilyticus XDB9(T) (96.7â% 16S rRNA gene sequence similarity) and Lysinibacillus odysseyi 34hs-1(T) (96.5â%). DNA-DNA relatedness between the isolate and L. odysseyi DSM 18869(T) was very low (6â%). On the basis of the data presented, strain WS 4626(T) represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillus meyeri sp. nov. is proposed. The type strain is WS 4626(T) (â=âDSM 25057(T)â=âLMG 26643(T)).