scholarly journals Antibiotic susceptibility and phylogenetic analyses for the origins and serotypes of Listeriamonocytogenes strains isolated from ice cream and cream cakes

2020 ◽  
Vol 44 (5) ◽  
pp. 1100-1109
Author(s):  
Orkun BABACAN

Listeria monocytogenes is a zoonotic bacterium which also infects humans. The aim of this study was to isolate this organism from cream cakes and ice cream and obtain 16S rRNA and hlyA gene sequences from isolates in order to perform phylogenetic analyses. Serotypes and antibiotic susceptibility were also determined. The cream cake and ice cream samples were examined for L. monocytogenes according to ISO 11290-1 and using the mini Vidas LMO 2 kit procedure. Antibiotic susceptibilities were investigated using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI) standards. The Sanger DNA sequencing method for phylogenetic analysis was used for L. monocytogenes isolates. A total of 16 (n =128, 12.50%) L. monocytogenes strains, 9 (12.16%) from cream cake samples and 7 (12.96%) from ice cream samples, were isolated. This was the first investigation involving sequencing of L. monocytogenes isolated from cream cakes and ice creams in Turkey. All isolates were susceptible to sulfamethoxazole/trimethoprim, tetracycline, streptomycin, gentamicin, meropenem, and erythromycin. The numbers of isolates resistant to sulbactam/ampicillin, penicillin G, chloramphenicol, and ampicillin were 16, 2, 1, and 1, respectively. Moreover, 3 isolates showed intermediate resistance to amikacin and 2 to ciprofloxacin. The hlyA gene sequences of 11 of the L. monocytogenesisolates isolated from milk were closely related to the hlyA gene sequences of the GenBank reference strains. The comparison of the 16s rRNA gene sequences of the L. monocytogenes strains with the GenBank reference serotypes identified 1 isolate as serotype 1/2c, 1 as serotype 1/2a, and 1 as serotype 4. Nucleic acid sequencing is useful for identification of L. monocytogenes. The 16S rRNAand hlyA sequences can be used to determine the origin and relationship between L. monocytogenesisolates, as well as the serotype.

2011 ◽  
Vol 61 (5) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ki-Hoon Oh ◽  
Yong-Taek Jung ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon

A Gram-negative-staining, non-motile and rod-shaped bacterial strain, HD-28T, was isolated from a tidal flat of the Yellow Sea, Korea. Strain HD-28T grew optimally at pH 7.0–8.0 and 30 °C in the presence of 2–3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain HD-28T was most closely related to species of the genus Ruegeria and exhibited 95.5–96.9 % 16S rRNA gene sequence similarity to the type strains of Ruegeria species. A neighbour-joining phylogenetic tree based on gyrB gene sequences also showed that strain HD-28T fell within the cluster comprising recognized species of the genus Ruegeria, showing 77.5–83.9 % sequence similarity. Strain HD-28T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the major fatty acid. The major polar lipids detected in strain HD-28T were phosphatidylcholine, phosphatidylglycerol, an unidentified aminolipid and two unidentified lipids. The DNA G+C content was 57.9 mol%. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain HD-28T could be distinguished from recognized species of the genus Ruegeria. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain HD-28T is considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria faecimaris sp. nov. is proposed. The type strain is HD-28T ( = KCTC 23044T = CCUG 58878T).


2006 ◽  
Vol 56 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Bénédicte Lafay ◽  
Erika Bullier ◽  
Jeremy J. Burdon

Rhizobial bacteria almost exclusively nodulate members of the families Fabaceae, Mimosaceae and Caesalpiniaceae, but are found on a single non-legume taxon, Parasponia (Ulmaceae). Based on their host-range, their nitrogen-fixing ability and strain competition experiments, bacterial strains isolated from Parasponia were thought to constitute a separate lineage that would account for their exceptional host affinity. This hypothesis was investigated by focusing on four isolates that are representative of the morphological and cultural types of Parasponia-nodulating bradyrhizobia. Their evolutionary relationships with other rhizobia were analysed using 16S rRNA gene sequences and their nodulation properties were explored using the nodA gene as a proxy for host-range specificity. Phylogenetic analyses of the 16S rRNA and nodA gene sequences revealed that bacterial isolates from Parasponia species are embedded among other bradyrhizobia. They did not cluster together in topologies based on the 16S rRNA or nodA gene sequences, but were scattered among other bradyrhizobia belonging to either the Bradyrhizobium japonicum or the Bradyrhizobium elkanii lineages. These data suggest that the ability of some bradyrhizobia to nodulate species of the genus Parasponia does not represent a historical relationship that predates the relationship between rhizobia and legumes, but is probably a more recent host switch for some rhizobia.


2013 ◽  
Vol 63 (Pt_5) ◽  
pp. 1906-1911 ◽  
Author(s):  
Shih-Yi Sheu ◽  
Yu-Wen Shiau ◽  
Yan-Ting Wei ◽  
Wen-Ming Chen

To investigate the biodiversity of bacteria in the spring water of the Chengcing Lake Park in Taiwan, a Gram-stain-negative, rod-shaped, non-motile, non-spore-forming and aerobic bacterial strain, designated strain Chen16-4T, was isolated and characterized in a taxonomic study using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that the closest relatives of strain Chen16-4T were Sphingobium amiense YTT, Sphingobium yanoikuyae GIFU 9882T and Sphingobium scionense WP01T, with sequence similarities of 97.6, 97.1 and 97.0 %, respectively. A phylogenetic tree obtained with 16S rRNA gene sequences indicated that strain Chen16-4T and these three closest relatives formed an independent phylogenetic clade within the genus Sphingobium . The polar lipid pattern, the presence of spermidine and ubiquinone Q-10, the predominance of C18 : 1ω7c in the cellular fatty acid profile and the DNA G+C content also supported affiliation of the isolate to the genus Sphingobium . The DNA–DNA relatedness of strain Chen16-4T with respect to recognized species of the genus Sphingobium was less than 70 %. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain Chen16-4T represents a novel species in the genus Sphingobium , for which the name Sphingobium fontiphilum sp. nov. is proposed. The type strain is Chen16-4T ( = BCRC 80308T = LMG 26342T = KCTC 23559T).


2010 ◽  
Vol 60 (11) ◽  
pp. 2552-2556 ◽  
Author(s):  
Ping Fa Zhou ◽  
Wei Min Chen ◽  
Ge Hong Wei

Previously, five rhizobial strains isolated from root nodules of Robinia pseudoacacia were assigned to the same genospecies on the basis of identical 16S rRNA gene sequences and phylogenetic analyses of the nodA, nodC and nifH genes, in which the five isolates formed a well-supported group that excluded other sequences found in public databases. In this study, the 16S rRNA gene sequence similarities between the isolates and Mesorhizobium mediterraneum UPM-Ca36T and Mesorhizobium temperatum SDW018T were 99.5 and 99.6 %, respectively. The five isolates were also different from defined Mesorhizobium species using ERIC fingerprint profiles and they formed a novel Mesorhizobium lineage in phylogenetic analyses of recA and atpD gene sequences. DNA–DNA relatedness values between the representative strain, CCNWYC 115T, and type strains of defined Mesorhizobium species were found to be lower than 47.5 %. These results indicated that the isolates represented a novel genomic species. Therefore, a novel species, Mesorhizobium robiniae sp. nov., is proposed, with type strain CCNWYC 115T (=ACCC 14543T =HAMBI 3082T). Strain CCNWYC 115T can form effective nodules only on its original host.


2007 ◽  
Vol 57 (6) ◽  
pp. 1217-1221 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, motile and helical-shaped bacterial strains, K92T and K93, were isolated from sludge from a dye works in Korea, and their taxonomic positions were investigated by means of a polyphasic approach. Strains K92T and K93 grew optimally at 37 °C and pH 7.0–8.0 in the presence of 0.5 % (w/v) NaCl. They contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified amino-group-containing lipids that were ninhydrin-positive. Their DNA G+C contents were 70.0 mol%. The 16S rRNA gene sequences of K92T and K93 showed no differences, and the two strains had a mean DNA–DNA relatedness of 93 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains K92T and K93 formed a distinct evolutionary lineage within the Alphaproteobacteria. The 16S rRNA gene sequences of strains K92T and K93 exhibited similarity values of less than 91.5 % with respect to the 16S rRNA gene sequences of other members of the Alphaproteobacteria. The two strains were distinguishable from phylogenetically related genera through differences in several phenotypic properties. On the basis of the phenotypic, phylogenetic and genetic data, strains K92T and K93 represent a novel genus and species, for which the name Caenispirillum bisanense gen. nov., sp. nov. is proposed. The type strain of Caenispirillum bisanense is K92T (=KCTC 12839T=JCM 14346T).


2007 ◽  
Vol 57 (9) ◽  
pp. 2037-2051 ◽  
Author(s):  
M. Martini ◽  
I.-M. Lee ◽  
K. D. Bottner ◽  
Y. Zhao ◽  
S. Botti ◽  
...  

Extensive phylogenetic analyses were performed based on sequences of the 16S rRNA gene and two ribosomal protein (rp) genes, rplV (rpl22) and rpsC (rps3), from 46 phytoplasma strains representing 12 phytoplasma 16Sr groups, 16 other mollicutes and 28 Gram-positive walled bacteria. The phylogenetic tree inferred from rp genes had a similar overall topology to that inferred from the 16S rRNA gene. However, the rp gene-based tree gave a more defined phylogenetic interrelationship among mollicutes and Gram-positive walled bacteria. Both phylogenies indicated that mollicutes formed a monophyletic group. Phytoplasmas clustered with Acholeplasma species and formed one clade paraphyletic with a clade consisting of the remaining mollicutes. The closest relatives of mollicutes were low-G+C-content Gram-positive bacteria. Comparative phylogenetic analyses using the 16S rRNA gene and rp genes were performed to evaluate their efficacy in resolving distinct phytoplasma strains. A phylogenetic tree was constructed based on analysis of rp gene sequences from 87 phytoplasma strains belonging to 12 16Sr phytoplasma groups. The phylogenetic relationships among phytoplasmas were generally in agreement with those obtained on the basis of the 16S rRNA gene in the present and previous works. However, the rp gene-based phylogeny allowed for finer resolution of distinct lineages within the phytoplasma 16Sr groups. RFLP analysis of rp gene sequences permitted finer differentiation of phytoplasma strains in a given 16Sr group. In this study, we also designed several semi-universal and 16Sr group-specific rp gene-based primers that allow for the amplification of 11 16Sr group phytoplasmas.


2006 ◽  
Vol 56 (6) ◽  
pp. 1251-1255 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

A Gram-negative, non-motile, non-spore-forming, slightly halophilic bacterial strain, DSW-5T, was isolated from seawater off Dokdo, Korea, and subjected to a polyphasic taxonomic study. It grew optimally at 25–28 °C and in the presence of 2 % (w/v) NaCl. Strain DSW-5T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C15 : 1 and iso-C15 : 0 3-OH as the major fatty acids. The major polar lipids detected were phosphatidylethanolamine, three unidentified phospholipids and an amino-group-containing lipid. The DNA G+C content was 30.0 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DSW-5T was most closely related to the genus Polaribacter. Similarity values between the 16S rRNA gene sequences of strain DSW-5T and the type strains of recognized Polaribacter species were in the range 96.2–96.8 %. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DSW-5T (=KCTC 12392T=DSM 17204T) was classified in the genus Polaribacter as the type strain of a novel species, for which the name Polaribacter dokdonensis sp. nov. is proposed.


2006 ◽  
Vol 56 (4) ◽  
pp. 777-780 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Mi-Hwa Lee ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

A Gram-negative, non-motile, non-spore-forming bacterial strain, DS-44T, was isolated from soil from Dokdo in Korea, and its taxonomic position was investigated by using a polyphasic approach. It grew optimally at 25 °C and in the presence of 2 % (w/v) NaCl. Strain DS-44T contained MK-7 as the predominant menaquinone and iso-C15 : 0 and C16 : 1 ω7c and/or iso-C15 : 0 2-OH as the major fatty acids. The DNA G+C content was 49·0 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DS-44T belongs to the genus Algoriphagus of the phylum Bacteroidetes. Similarity values between the 16S rRNA gene sequences of strain DS-44T and those of the type strains of recognized Algoriphagus species were in the range 93·8–95·7 %, making it possible to categorize strain DS-44T as a species that is separate from previously described Algoriphagus species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DS-44T (=KCTC 12545T=CIP 108837T) was classified in the genus Algoriphagus as the type strain of a novel species, for which the name Algoriphagus terrigena sp. nov. is proposed.


2007 ◽  
Vol 57 (10) ◽  
pp. 2259-2261 ◽  
Author(s):  
Jongsik Chun ◽  
Jae-Hak Lee ◽  
Yoonyoung Jung ◽  
Myungjin Kim ◽  
Seil Kim ◽  
...  

16S rRNA gene sequences have been widely used for the identification of prokaryotes. However, the flood of sequences of non-type strains and the lack of a peer-reviewed database for 16S rRNA gene sequences of type strains have made routine identification of isolates difficult and labour-intensive. In the present study, we generated a database containing 16S rRNA gene sequences of all prokaryotic type strains. In addition, a web-based tool, named EzTaxon, for analysis of 16S rRNA gene sequences was constructed to achieve identification of isolates based on pairwise nucleotide similarity values and phylogenetic inference methods. The system developed provides users with a similarity-based search, multiple sequence alignment and various phylogenetic analyses. All of these functions together with the 16S rRNA gene sequence database of type strains can be successfully used for automated and reliable identification of prokaryotic isolates. The EzTaxon server is freely accessible over the Internet at http://www.eztaxon.org/


2015 ◽  
Vol 65 (Pt_1) ◽  
pp. 56-64 ◽  
Author(s):  
Ivana Orthová ◽  
Peter Kämpfer ◽  
Stefanie P. Glaeser ◽  
René Kaden ◽  
Hans-Jürgen Busse

A Gram-negative, rod-shaped and motile bacterial isolate, designated strain NS9T, isolated from air of the Sainsbury Centre for Visual Arts in Norwich, UK, was subjected to a polyphasic taxonomic study including phylogenetic analyses based on partial 16S rRNA, gyrB and lepA gene sequences and phenotypic characterization. The 16S rRNA gene sequence of NS9T identified Massilia haematophila CCUG 38318T, M. niastensis 5516S-1T (both 97.7 % similarity), M. aerilata 5516S-11T (97.4 %) and M. tieshanensis TS3T (97.4 %) as the next closest relatives. In partial gyrB and lepA sequences, NS9T shared the highest similarities with M. haematophila CCUG 38318T (94.5 %) and M. aerilata 5516-11T (94.3 %), respectively. These sequence data demonstrate the affiliation of NS9T to the genus Massilia . The detection of the predominant ubiquinone Q-8, a polar lipid profile consisting of the major compounds diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol and a polyamine pattern containing 2-hydroxyputrescine and putrescine were in agreement with the assignment of strain NS9T to the genus Massilia . Major fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0, C18 : 1ω7c and C10 : 0 3-OH. Dissimilarities in partial lepA and gyrB gene sequences as well as results from DNA–DNA hybridizations demonstrate that strain NS9T is a representative of an as-yet undescribed species of the genus Massilia that is also distinguished from its close relatives based on physiological and biochemical traits. Hence, we describe a novel species, for which we propose the name Massilia norwichensis sp. nov., with the type strain NS9T ( = CCUG 65457T = LMG 28164T).


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