qnrA gene diversity in Shewanella spp.

Microbiology ◽  
2021 ◽  
Vol 167 (12) ◽  
Author(s):  
S. Araújo ◽  
S. R. Azenha ◽  
I. Henriques ◽  
M. Tacão

Members of Shewanella are ubiquitous in aquatic environments, some of which have been implicated in human infections. The progenitors of antibiotic resistance genes with clinical relevance, such as qnrA genes, have been identified in Shewanella. qnrA code for a pentapeptide repeat protein that protects type II topoisomerases, decreasing susceptibility to quinolones and fluoroquinolones. In this study, 248 genomes of 49 Shewanella species were analysed as well as 33 environmental isolates belonging to 10 Shewanella species. The presence of the qnrA gene was detected in 22.9% of the genomes and 15.2% of the isolates. The gene was more often detected in Shewanella algae , but was also detected in Shewanella carassii , Shewanella chilikensis , Shewanella haliotis and Shewanella indica . The identified genes encoded the previously described variants QnrA3 (in 22 genomes of one species), QnrA2 (eight genomes and three species), QnrA1 (six genomes and two species), QnrA7 (five genomes and two species), QnrA10 (two genomes of one species) and QnrA4 (one genome). In addition, 11 novel variants with 3 to 7 amino acid substitutions were identified (in 13 genomes and one environmental isolate). The presence of this gene appears to be species-specific although within some species several variants were detected. The study presents a previously unknown diversity of qnrA in Shewanella , highlighting the role of this genus as progenitor and reservoir of these genes. Further studies are needed to determine the phenotypes conferred by the new variants and the mechanisms that may mediate the transfer of these genes to new hosts.

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Paulina Glajzner ◽  
Eligia Maria Szewczyk ◽  
Magdalena Szemraj

Bacteria of the genus Streptococcus , earlier considered typically animal, currently have also been causing infections in humans. It is necessary to make clinicians aware of the emergence of new species that may cause the development of human diseases. There is an increasing frequency of isolation of streptococci such as S. suis , S. dysgalactiae , S. iniae and S. equi from people. Isolation of Streptococcus bovis/Streptococcus equinus complex bacteria has also been reported. The streptococcal species described in this review are gaining new properties and virulence factors by which they can thrive in new environments. It shows the potential of these bacteria to changes in the genome and the settlement of new hosts. Information is presented on clinical cases that concern streptococcus species belonging to the groups Bovis, Pyogenic and Suis. We also present the antibiotic resistance profiles of these bacteria. The emerging resistance to β-lactams has been reported. In this review, the classification, clinical characteristics and antibiotic resistance of groups and species of streptococci considered as animal pathogens are summarized.


2014 ◽  
Vol 64 (Pt_9) ◽  
pp. 3146-3152 ◽  
Author(s):  
Sylvain Brisse ◽  
Virginie Passet ◽  
Patrick A. D. Grimont

Strains previously classified as members of Klebsiella pneumoniae phylogroups KpI, KpII-A, KpII-B and KpIII were characterized by 16S rRNA (rrs) gene sequencing, multilocus sequence analysis based on rpoB, fusA, gapA, gyrA and leuS genes, average nucleotide identity and biochemical characteristics. Phylogenetic analysis demonstrated that KpI and KpIII corresponded to K. pneumoniae and Klebsiella variicola , respectively, whereas KpII-A and KpII-B formed two well-demarcated sequence clusters distinct from other members of the genus Klebsiella . Average nucleotide identity between KpII-A and KpII-B was 96.4 %, whereas values lower than 94 % were obtained for both groups when compared with K. pneumoniae and K. variicola . Biochemical properties differentiated KpII-A, KpII-B, K. pneumoniae and K. variicola , with acid production from adonitol and l-sorbose and ability to use 3-phenylproprionate, 5-keto-d-gluconate and tricarballylic acid as sole carbon sources being particularly useful. Based on their genetic and phenotypic characteristics, we propose the names Klebsiella quasipneumoniae subsp. quasipneumoniae subsp. nov. and K. quasipneumoniae subsp. similipneumoniae subsp. nov. for strains of KpII-A and KpII-B, respectively. The type strain of K. quasipneumoniae sp. nov. and of K. quasipneumoniae subsp. quasipneumoniae subsp. nov. is 01A030T ( = SB11T = CIP 110771T = DSM 28211T). The type strain of K. quasipneumoniae subsp. similipneumoniae subsp. nov. is 07A044T ( = SB30T = CIP 110770T = DSM 28212T). Both strains were isolated from human blood cultures. This work also showed that Klebsiella singaporensis is a junior heterotypic synonym of K. variicola .


2021 ◽  
Vol 7 (5) ◽  
Author(s):  
Antoni P. A. Hendrickx ◽  
Fabian Landman ◽  
Angela de Haan ◽  
Sandra Witteveen ◽  
Marga G. van Santen-Verheuvel ◽  
...  

Carbapenem-hydrolysing enzymes belonging to the OXA-48-like group are encoded by bla OXA-48-like alleles and are abundant among Enterobacterales in the Netherlands. Therefore, the objective here was to investigate the characteristics, gene content and diversity of the bla OXA-48-like carrying plasmids and chromosomes of Escherichia coli and Klebsiella pneumoniae collected in the Dutch national surveillance from 2014 to 2019 in comparison with genome sequences from 29 countries. A combination of short-read genome sequencing with long-read sequencing enabled the reconstruction of 47 and 132 complete bla OXA-48-like plasmids for E. coli and K. pneumoniae , respectively. Seven distinct plasmid groups designated as pOXA-48-1 to pOXA-48-5, pOXA-181 and pOXA-232 were identified in the Netherlands which were similar to internationally reported plasmids obtained from countries from North and South America, Europe, Asia and Oceania. The seven plasmid groups varied in size, G+C content, presence of antibiotic resistance genes, replicon family and gene content. The pOXA-48-1 to pOXA-48-5 plasmids were variable, and the pOXA-181 and pOXA-232 plasmids were conserved. The pOXA-48-1, pOXA-48-2, pOXA-48-3 and pOXA-48-5 groups contained a putative conjugation system, but this was absent in the pOXA-48-4, pOXA-181 and pOXA-232 plasmid groups. pOXA-48 plasmids contained the PemI antitoxin, while the pOXA-181 and pOXA-232 plasmids did not. Furthermore, the pOXA-181 plasmids carried a virB2-virB3-virB9-virB10-virB11 type IV secretion system, while the pOXA-48 plasmids and pOXA-232 lacked this system. A group of non-related pOXA-48 plasmids from the Netherlands contained different resistance genes, non-IncL-type replicons or no replicons. Whole genome multilocus sequence typing revealed that the bla OXA-48-like plasmids were found in a wide variety of genetic backgrounds in contrast to chromosomally encoded bla OXA-48-like alleles. Chromosomally localized bla OXA-48 and bla OXA-244 alleles were located on genetic elements of variable sizes and comprised regions of pOXA-48 plasmids. The bla OXA-48-like genetic element was flanked by a direct repeat upstream of IS1R, and was found at multiple locations in the chromosomes of E. coli . Lastly, K. pneumoniae isolates carrying bla OXA-48 or bla OXA-232 were mostly resistant for meropenem, whereas E. coli bla OXA-48, bla OXA-181 and chromosomal bla OXA-48 or bla OXA-244 isolates were mostly sensitive. In conclusion, the overall bla OXA-48-like plasmid population in the Netherlands is conserved and similar to that reported for other countries, confirming global dissemination of bla OXA-48-like plasmids. Variations in size, presence of antibiotic resistance genes and gene content impacted pOXA-48, pOXA-181 and pOXA-232 plasmid architecture.


2020 ◽  
Vol 70 (8) ◽  
pp. 4767-4773 ◽  
Author(s):  
Jong-Shian Liou ◽  
Chien-Hsun Huang ◽  
Nao Ikeyama ◽  
Ai-Yun Lee ◽  
I-Ching Chen ◽  
...  

A strictly anaerobic predominant bacterium, designated as strain gm001T, was isolated from a freshly voided faecal sample collected from a healthy Taiwanese adult. Cells were Gram-stain-negative rods, non-motile and non-spore-forming. Strain gm001T was identified as a member of the genus Prevotella , and a comparison of 16S rRNA and hsp60 gene sequences revealed sequence similarities of 98.5 and 93.3 %, respectively, demonstrating that it was most closely related to the type strain of Prevotella copri . Phylogenomic tree analysis indicated that the gm001T cluster is an independent lineage of P. copri DSM 18205T. The average nucleotide identity, digital DNA‒DNA hybridization and average amino acid identity values between strain gm001T and P. copri DSM 18205T were 80.9, 28.6 and 83.8 %, respectively, which were clearly lower than the species delineation thresholds. The species-specific genes of this novel species were also identified on the basis of pan-genomic analysis. The predominant menaquinones were MK-11 and MK-12, and the predominant fatty acids were anteiso-C15 : 0, C15 : 0 and iso-C15 : 0. Acetate and succinate were produced from glucose as metabolic end products. Taken together, the results indicate that strain gm001T represents a novel species of the genus Prevotella , for which the name Prevotella hominis sp. nov. is proposed. The type strain is gm001T (=BCRC 81118T=JCM 33280T).


2021 ◽  
Vol 7 (8) ◽  
Author(s):  
Marie Petitjean ◽  
Bénédicte Condamine ◽  
Charles Burdet ◽  
Erick Denamur ◽  
Etienne Ruppé

Escherichia coli is a ubiquitous bacterium that has been widely exposed to antibiotics over the last 70 years. It has adapted by acquiring different antibiotic-resistance genes (ARGs), the census of which we aim to characterize here. To do so, we analysed 70 301 E. coli genomes obtained from the EnteroBase database and detected 1 027 651 ARGs using the AMRFinder, Mustard and ResfinderFG ARG databases. We observed a strong phylogroup and clonal lineage specific distribution of some ARGs, supporting the argument for epistasis between ARGs and the strain genetic background. However, each phylogroup had ARGs conferring a similar antibiotic class resistance pattern, indicating phenotypic adaptive convergence. The G+C content or the type of ARG was not associated with the frequency of the ARG in the database. In addition, we identified ARGs from anaerobic, non- Proteobacteria bacteria in four genomes of E. coli , supporting the hypothesis that the transfer between anaerobic bacteria and E. coli can spontaneously occur but remains exceptional. In conclusion, we showed that phylum barrier and intra-species phylogenetic history are major drivers of the acquisition of a resistome in E. coli .


2020 ◽  
Vol 2 (11) ◽  
Author(s):  
Keerthana Ponni Kandasamy ◽  
Radhesh Krishnan Subramanian ◽  
Radhakrishnan Srinivasan ◽  
Sengali Ragunath ◽  
G. Balaji ◽  
...  

Macro-algae are a good source of agar oligosaccharides, which can be obtained through bacterial enzymatic hydrolysis. The agarase enzyme secreted by the micro-organisms cleaves the cell wall of the algae and releases agar oligosaccharides as degradation products with various applications. Agarolytic bacteria were isolated from the marine algae Kappaphycus sp., and Sargassum sp., and studied for their agar-degrading properties. Among the 70 isolates, 2 isolates (A13 and Sg8) showed agarase activity in in vitro assays. The maximum agarolytic index was recorded in the isolate Sg8 (3.75 mm and 4.29 µg ml−1 agarase activity), followed by the isolate A13 (2.53 mm and 2.6 µg ml−1 agarase activity). Optimum agarase production of isolate Sg8 was observed at pH7 and at a temperature of 25 °C in 24–48 h, whereas for isolate A13 the optimum production was at pH7 and at a temperature of 37 °C in 48 h. The identities of the agarolytic isolates (Sg8 and A13) were confirmed based on microscopy, morphological, biochemical and molecular analysis as Shewanella algae [National Center for Biotechnology Information (NCBI) GenBank accession number MK121204.1] and Microbulbifer elongatus [NCBI GenBank accession number MK825484.1], respectively.


2021 ◽  
Vol 7 (6) ◽  
Author(s):  
Haleluya Wami ◽  
Alexander Wallenstein ◽  
Daniel Sauer ◽  
Monika Stoll ◽  
Rudolf von Bünau ◽  
...  

The bacterial genotoxin colibactin interferes with the eukaryotic cell cycle by causing dsDNA breaks. It has been linked to bacterially induced colorectal cancer in humans. Colibactin is encoded by a 54 kb genomic region in Enterobacteriaceae . The colibactin genes commonly co-occur with the yersiniabactin biosynthetic determinant. Investigating the prevalence and sequence diversity of the colibactin determinant and its linkage to the yersiniabactin operon in prokaryotic genomes, we discovered mainly species-specific lineages of the colibactin determinant and classified three main structural settings of the colibactin–yersiniabactin genomic region in Enterobacteriaceae . The colibactin gene cluster has a similar but not identical evolutionary track to that of the yersiniabactin operon. Both determinants could have been acquired on several occasions and/or exchanged independently between enterobacteria by horizontal gene transfer. Integrative and conjugative elements play(ed) a central role in the evolution and structural diversity of the colibactin–yersiniabactin genomic region. Addition of an activating and regulating module (clbAR) to the biosynthesis and transport module (clbB-S) represents the most recent step in the evolution of the colibactin determinant. In a first attempt to correlate colibactin expression with individual lineages of colibactin determinants and different bacterial genetic backgrounds, we compared colibactin expression of selected enterobacterial isolates in vitro. Colibactin production in the tested Klebsiella species and Citrobacter koseri strains was more homogeneous and generally higher than that in most of the Escherichia coli isolates studied. Our results improve the understanding of the diversity of colibactin determinants and its expression level, and may contribute to risk assessment of colibactin-producing enterobacteria.


2021 ◽  
Vol 7 (12) ◽  
Author(s):  
Alexander Laskey ◽  
John Devenish ◽  
Mingsong Kang ◽  
Mirjana Savic ◽  
John Chmara ◽  
...  

Ingestion of food- or waterborne antibiotic-resistant bacteria may lead to dissemination of antibiotic resistance genes (ARGs) in the gut microbiota. The gut microbiota often suffers from various disturbances. It is not clear whether and how disturbed microbiota may affect ARG mobility under antibiotic treatments. For proof of concept, in the presence or absence of streptomycin pre-treatment, mice were inoculated orally with a β-lactam-susceptible Salmonella enterica serovar Heidelberg clinical isolate (recipient) and a β-lactam resistant Escherichia coli O80:H26 isolate (donor) carrying a blaCMY-2 gene on an IncI2 plasmid. Immediately following inoculation, mice were treated with or without ampicillin in drinking water for 7 days. Faeces were sampled, donor, recipient and transconjugant were enumerated, blaCMY-2 abundance was determined by quantitative PCR, faecal microbial community composition was determined by 16S rRNA amplicon sequencing and cecal samples were observed histologically for evidence of inflammation. In faeces of mice that received streptomycin pre-treatment, the donor abundance remained high, and the abundance of S. Heidelberg transconjugant and the relative abundance of Enterobacteriaceae increased significantly during the ampicillin treatment. Co-blooming of the donor, transconjugant and commensal Enterobacteriaceae in the inflamed intestine promoted significantly (P<0.05) higher and possibly wider dissemination of the blaCMY-2 gene in the gut microbiota of mice that received the combination of streptomycin pre-treatment and ampicillin treatment (Str–Amp) compared to the other mice. Following cessation of the ampicillin treatment, faecal shedding of S. Heidelberg transconjugant persisted much longer from mice in the Str–Amp group compared to the other mice. In addition, only mice in the Str–Amp group shed a commensal E. coli O2:H6 transconjugant, which carries three copies of the blaCMY-2 gene, one on the IncI2 plasmid and two on the chromosome. The findings highlight the significance of pre-existing gut microbiota for ARG dissemination and persistence during and following antibiotic treatments of infectious diseases.


2020 ◽  
Vol 6 (10) ◽  
Author(s):  
Yuqing Feng ◽  
Xuezheng Fan ◽  
Liangquan Zhu ◽  
Xinyue Yang ◽  
Yan Liu ◽  
...  

Clostridium perfringens is associated with a variety of diseases in both humans and animals. Recent advances in genomic sequencing make it timely to re-visit this important pathogen. Although the genome sequence of C. perfringens was first determined in 2002, large-scale comparative genomics with isolates of different origins is still lacking. In this study, we used whole-genome sequencing of 45 C . perfringens isolates with isolation time spanning an 80‐year period and performed comparative analysis of 173 genomes from worldwide strains. We also conducted phylogenetic lineage analysis and introduced an openness index (OI) to evaluate the openness of bacterial genomes. We classified all these genomes into five lineages and hypothesized that the origin of C. perfringens dates back to ~80 000 years ago. We showed that the pangenome of the 173 C . perfringens strains contained a total of 26 954 genes, while the core genome comprised 1020 genes, accounting for about a third of the genome of each isolate. We demonstrated that C. perfringens had the highest OI compared with 51 other bacterial species. Intact prophage sequences were found in nearly 70.0 % of C. perfringens genomes, while CRISPR sequences were found only in ~40.0 %. Plasmids were prevalent in C. perfringens isolates, and half of the virulence genes and antibiotic resistance genes (ARGs) identified in all the isolates could be found in plasmids. ARG-sharing network analysis showed that C. perfringens shared its 11 ARGs with 55 different bacterial species, and a high frequency of ARG transfer may have occurred between C. perfringens and species in the genera Streptococcus and Staphylococcus . Correlation analysis showed that the ARG number in C. perfringens strains increased with time, while the virulence gene number was relative stable. Our results, taken together with previous studies, revealed the high genome openness and genetic diversity of C. perfringens and provide a comprehensive view of the phylogeny, genomic features, virulence gene and ARG profiles of worldwide strains.


2020 ◽  
Vol 70 (8) ◽  
pp. 4637-4645 ◽  
Author(s):  
Vincent Perreten ◽  
Stephen A. Kania ◽  
David Bemis

Six Staphylococcus strains were isolated from healthy black bears (Ursus americanus) in the Great Smoky Mountains National Park, Tennessee, USA. Phylogenetic analysis based on complete genome, 16S rRNA, dnaJ, hsp60, rpoB and sodA genes, and MALDI-TOF-MS main spectral profiles revealed that the strains belonged to one species and showed the closest relatedness to members of the ‘ Staphylococcus intermedius group’ (SIG), which include Staphylococcus intermedius , Staphylococcus pseudintermedius, Staphylococcus delphini and Staphyloccoccus cornubiensis. The strains were positive in SIG-specific and negative in individual species-specific PCR assays for the nuc gene. The strains can be differentiated from the other SIG species by the absence of sucrose fermentation, from S. intermedius DSM 20373T, S. pseudintermedius CCUG 49543T and S. cornubiensis DSM 105366T by the absence of methyl β-d-glucopyranoside fermentation and from S. delphini DSM 20771T by fermentation of trehalose. DNA relatedness of the type strain MI 10-1553T with the type strains of S. delphini , S. pseudintermedius , S. intermedius and S. cornubiensis was ≤48.2 % by digital DNA–DNA hybridization and ≤92.3 % by average nucleotide identity calculations. Iso-C15:0, anteiso-C15 : 0 and anteiso-C17 : 0 were the most common fatty acids. Polar lipids consisted of phosphadidylglycerols, phospholipids, glycolipid, diphosphatidylglycerol and aminophospholipid. Cell-wall peptidoglycan was of type A3α l-Lys-Gly3 (Ser; similar to A11.2 and A11.3). The respiratory quinone belonged to menaquinone 7 (MK-7). The G+C content of MI 10-1553T was 39.3 mol%. The isolated strains represent a novel species of the genus Staphylococcus , for which we propose the name Staphylococcus ursi sp. nov. The type strain is MI 10-1553T (=ATCC TSD-55T=CCOS 1900T).


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