ABSTRACT
A bacterial strain was isolated from a brackish water sample of Tagus river, Alcochete, Portugal and was designated TO1_6T. It forms light pink colonies on M13 medium supplemented with N-acetylglucosamine. Cells are pear-shaped to spherical, form rosettes and divide by budding. Strain TO1_6T presents a mesophilic and neutrophilic profile, with optimum growth at 20 to 25 °C and pH 7.0 to 7.5, and vitamin supplementation is not required to promote its growth. The genome of the novel isolate is 7.77 Mbp in size and has a DNA G + C content of 56.3%. Based on its 16S rRNA gene sequence, this strain is affiliated with the phylum Planctomycetota. Further taxonomic characterization using additional phylogenetic markers, namely rpoB gene sequence (encoding the ß-subunit of the DNA-dependent RNA polymerase), as well as Percentage of conserved proteins, average nucleotide identity and average amino acid identity, suggest the affiliation of strain TO1_6T to the genus Stieleria, a recently described taxon in the family Pirellulaceae, order Pirellulales and class Planctomycetia. Based on the genotypic, phylogenetic and physiological characterization, we here describe a new species represented by the type strain TO1_6T (= CECT 30432T, = LMG 32465T), for which the name Stieleria tagensis sp. nov. is proposed.
Subject(s)
Fatty Acids , Rivers , Rivers/microbiology , Fatty Acids/analysis , Phospholipids/analysis , Planctomycetes , Sequence Analysis, DNA , Phylogeny , RNA, Ribosomal, 16S/genetics , Portugal , DNA, Bacterial/genetics , DNA, Bacterial/chemistry , Bacterial Typing TechniquesABSTRACT
Antimicrobials are naturally produced by microbes and therefore have always been present in their environment, as well as accompanying resistance mechanisms. The antibiotic resistance profile of environmental species is particularly relevant since genetic determinants of resistance can spread through horizontal gene transfer and reach clinically important species. The phylum Planctomycetes comprises Gram-negative bacteria characterised by unusual features and appear to be ubiquitously distributed. Members of this group have recently been characterised as producers of bioactive compounds, namely antimicrobials, but their antibiotic susceptibility profile has been scarcely studied. In this study, the antibiotic susceptibility profile of six phylogenetically distinct strains of Planctomycetes was assessed. All strains showed resistance to beta-lactams, aminoglycosides and glycopeptides. Our results showed that antibiotics which target protein synthesis or DNA replication, with the exception of aminoglycosides, were the most effective against the tested strains. The highest efficacy was observed for chloramphenicol, clindamycin and ciprofloxacin. The highest level of antimicrobial resistance was observed in the uncharacterised novel taxon Planctomyces sp. strain FF15 which was only susceptible to erythromycin and ciprofloxacin.
Subject(s)
Anti-Bacterial Agents/pharmacology , Aquatic Organisms/drug effects , Planctomycetales/drug effects , Disk Diffusion Antimicrobial Tests , Drug Resistance, BacterialABSTRACT
Objectives: Information on clonal lineages and genetic platforms involved in the mobilization of carbapenemases between Pseudomonas aeruginosa strains in Portugal is scarce. Here, we outline the genetic drivers contributing to the occurrence of blaVIM-2-producing P. aeruginosa over two decades. Methods: A collection of carbapenem-resistant P. aeruginosa clinical isolates (n = 263, 1995-2014) was screened for carbapenemase production by Blue-Carba and PCR. Antimicrobial susceptibility testing was performed according to EUCAST and clonal analysis by MLST. Nine isolates representing different integrons and STs were selected for WGS, followed by bioinformatics. Results: Twenty-seven blaVIM-2-producing P. aeruginosa belonging to 10 STs were identified, with ST179 and ST111 being the most prevalent and persistent clones. blaVIM-2 was associated with seven class I integrons frequently co-harbouring aminoglycoside resistance genes. In58 was commonly identified, followed by derivatives and In100. blaVIM-2-harbouring transposons of the Tn3 and Tn402 families were linked to different plasmids or integrative conjugative elements of the clc family. Conclusions: The dissemination of blaVIM-2 carrying integrons is associated with a complex interplay between different mobile genetic elements, including the overlooked integrative conjugative elements, and successful spread of particular clones.
Subject(s)
Genotype , Interspersed Repetitive Sequences , Pseudomonas Infections/epidemiology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/enzymology , beta-Lactamases/metabolism , Genetic Variation , Humans , Microbial Sensitivity Tests , Multilocus Sequence Typing , Polymerase Chain Reaction , Portugal/epidemiology , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/isolation & purification , Whole Genome SequencingABSTRACT
Objectives: In Pseudomonas aeruginosa , bla VIM-2 has been mostly associated with a chromosomal location and rarely with a plasmid backbone. Until now, only three complete bla VIM-2 -carrying plasmid sequences have been described in this species. Here we explore the modular structure of pJB37, the first bla VIM-2 -carrying megaplasmid described in P. aeruginosa . Methods: The complete nucleotide sequence of plasmid pJB37 was determined with an Illumina HiSeq, with de novo assembly by SPAdes, annotation by RAST and searching for antimicrobial resistance genes and virulence factors. Conjugation assays were conducted. Results: Megaplasmid pJB37 (464â¯804 bp long and GC content of 57.2%) comprised: an IncP-2 repA-oriV-parAB region; a conjugative transfer region ( traF , traG , virD2 and trbBCDEJLFGI genes); Tn 6356 , a new putative bla VIM-2 -carrying transposon; heavy metal (mercury and tellurite) resistance operons; and an arsenal of virulence genes. Plasmid pJB37 was transferable by conjugation to a spontaneous rifampicin-resistant mutant of P. aeruginosa PAO1. Here, a bla VIM-2 -harbouring In58 integron was associated with a new complex transposable structure, herein named Tn 6356 , suggesting that In58 was most likely acquired by insertion of this element. Conclusions: The mosaic arrangement exhibited by the pJB37 IncP-2 megaplasmid, which highlights the vast assembly potential of distinct genetic elements in a Pseudomonas widespread plasmid platform, gives new insights into bacterial adaptation and evolution.
Subject(s)
DNA Transposable Elements , Plasmids , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/genetics , beta-Lactamases/genetics , Conjugation, Genetic , Gene Transfer, Horizontal , Humans , Pseudomonas Infections/microbiology , Sequence Analysis, DNAABSTRACT
Antimicrobial resistance is one of the leading causes of death worldwide and research on this topic has been on the spotlight for a long time. More recently and in agreement with the One Health Approach, the focus has moved towards the environmental resistome. Members of the phylum Planctomycetota are ubiquitously present in the environment including in hotspots for antimicrobial resistance selection and dissemination. Furthermore, phenotypic broad-range resistance has been observed in diverse members of this phylum. Here we review the evidence available on antimicrobial resistance in the underexploited Planctomycetota and highlight key aspects for future studies.
Subject(s)
Anti-Bacterial Agents , Bacteria , Drug Resistance, Bacterial , Bacteria/genetics , Bacteria/drug effects , Bacteria/classification , Bacteria/isolation & purification , Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial/genetics , Environmental MicrobiologyABSTRACT
Oysters are a highly valued seafood but can endanger public health, if they are eaten raw or barely cooked. We evaluated the microbiological quality of Pacific oysters (Magallana gigas) by international standard methods in four groups (each with four to five animals) acquired from supermarkets and directly from a farm producer. Most of the groups presented satisfactory microbiological quality. In two groups of oysters, 'questionable' or 'unsatisfactory' quality was observed for the coagulase-positive Staphylococcus parameter. Culture-based methods did not detect Salmonella spp. or enteropathogenic Vibrio spp., but Vibrio alginolyticus, a potential foodborne pathogen, was identified by molecular analysis. Fifty strains, belonging to 19 species, were isolated in antibiotic-supplemented media, and their antibiotic susceptibility profile was evaluated. Genes coding for ß-lactamases were searched by PCR in bacteria showing resistance phenotype. Decreased susceptibility or resistance to distinct antibiotics were observed for bacteria from depurated and non-depurated oysters. The blaTEM gene was identified in Escherichia fergusonii and Shigella dysenteriae strains, which showed multidrug-resistant phenotypes. The possibility that oysters might be a source of antibiotic-resistant bacteria/antibiotic resistance genes is of great concern and highlights the need for stricter controls and preventative measures to mitigate and counteract the dissemination of antibiotic resistance across the food chain.
Subject(s)
Ostreidae , Vibrio , Animals , Anti-Bacterial Agents/pharmacology , Ostreidae/microbiology , beta-Lactamases , Drug Resistance, MicrobialABSTRACT
The spread of OXA-24/OXA-40 (OXA-24/40)-producing Acinetobacter spp. in the Iberian Peninsula has been strongly influenced by clonal expansion, but the role of horizontal gene transfer has scarcely been explored. bla(OXA-24/40)-carrying plasmids and genetic environments were characterized in representative (n = 15) Acinetobacter species clinical isolates (obtained between 2001 and 2007) by Acinetobacter baumannii PCR-based replicon typing, sequencing, hybridization, and restriction fragment length polymorphism. Besides the identification of bla(OXA-24/40) within the chromosomes of some isolates, the circulation of common bla(OXA-24/40)-carrying plasmids (30-kb repA_AB; 10-kb aci2) and genetic backbones among Acinetobacter spp. was demonstrated.
Subject(s)
Acinetobacter/enzymology , Acinetobacter/genetics , Plasmids/genetics , Acinetobacter baumannii/enzymology , Acinetobacter baumannii/genetics , Gene Transfer, Horizontal/genetics , Molecular Sequence Data , Polymerase Chain Reaction , beta-Lactamases/geneticsABSTRACT
OBJECTIVES: this study focused on the population structure of OXA-23-producing Acinetobacter baumannii clinical isolates from Rio de Janeiro, Brazil. METHODS: the analysis included several genomic typing methods, including PFGE, two multilocus sequence typing (MLST) schemes, sequence group (SG) determination and bla(OXA-51-like) sequencing. The genomic context of the bla(OXA-23) gene was also evaluated using I-CeuI hybridizations and PCR assays. RESULTS: congruent clustering was obtained revealing four lineages. In accordance, four new sequence types (STs) (ST131, ST132, ST133 and ST134) were obtained with the MLST-OD scheme (associated with the Oxford Database) and four (ST79, ST15 and two new allelic profiles) with the MLST-IP scheme (developed by the Institute Pasteur). Four SGs (SG1, SG4 and two new profiles) were identified, allowing the association of 70% of the isolates with European clone II. bla(OXA-51-like) sequencing revealed the presence of bla(OXA-66), bla(OXA-69), bla(OXA-95) and bla(OXA-132). CONCLUSIONS: identification of new STs together with new SG profiles are findings suggestive of a local diversity hotspot that is worth exploring.
Subject(s)
Acinetobacter Infections/epidemiology , Acinetobacter Infections/microbiology , Acinetobacter baumannii/classification , Acinetobacter baumannii/enzymology , Genetic Variation , beta-Lactamases/biosynthesis , beta-Lactamases/genetics , Acinetobacter baumannii/genetics , Acinetobacter baumannii/isolation & purification , Bacterial Typing Techniques , Brazil/epidemiology , Cluster Analysis , Electrophoresis, Gel, Pulsed-Field , Genotype , Humans , Molecular Epidemiology , Molecular Typing , Nucleic Acid Hybridization , Polymerase Chain Reaction , Sequence Analysis, DNAABSTRACT
AIM: Acinetobacter bereziniae clinical relevance is starting to be recognized; however, very few descriptions of its carbapenem resistance currently exist. Here we characterize two carbapenem-resistant A. bereziniae isolates. MATERIALS & METHODS: Isolates were obtained from environmental and clinical samples. Carbapenemases were searched by phenotypic, biochemical and PCR assays. Clonality was studied by ApaI-PFGE and genetic location for carbapenemase genes were assessed by I-CeuI and S1 hybridizations. RESULTS: Isolates were not clonally related but both produced the 'exclusively Portuguese' IMP-5, with the clinical isolate also producing an OXA-58. The carbapenemase genes were plasmid located. CONCLUSION: Our results emphasize the role of non-baumannii Acinetobacter species as important reservoirs of clinically relevant resistance genes that could also contribute to their emergence as nosocomial pathogens.
Subject(s)
Acinetobacter Infections/drug therapy , Acinetobacter/drug effects , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Carbapenems/pharmacology , beta-Lactamases/genetics , Acinetobacter/genetics , Acinetobacter/isolation & purification , Acinetobacter Infections/microbiology , Humans , Microbial Sensitivity Tests , Plasmids/genetics , beta-Lactamases/biosynthesisABSTRACT
A screening study of the presence of metallo-beta-lactamases (IMP and VIM types and SPM-1) in isolates from different nonhospital sources was conducted, and it revealed the presence of bla(VIM-2), associated with the In58 class 1 integron, in two unrelated Pseudomonas aeruginosa strains from aquatic habitats. The results suggest that the hospital setting was the possible origin of these bla(VIM-2)-carrying strains.
Subject(s)
Gene Transfer, Horizontal , Hospitals , Pseudomonas aeruginosa/drug effects , Rivers/microbiology , Sewage/microbiology , beta-Lactamases/genetics , Animals , Drug Resistance, Bacterial/genetics , Ecosystem , Feces/microbiology , Humans , Integrons/genetics , Microbial Sensitivity Tests , Portugal , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/genetics , Pseudomonas aeruginosa/growth & development , beta-Lactamases/metabolism , beta-Lactams/pharmacologyABSTRACT
A multidisciplinary project was developed, combining the synthesis of a series of beta-nitrostyrene derivatives and the determination of their physicochemical parameters (redox potentials, partition coefficients), to the evaluation of the corresponding antibacterial activity. A complete conformational analysis was also performed, in order to get relevant structural information. Subsequently, a structure-property-activity (SPAR) approach was applied, through linear regression analysis, aiming at obtaining a putative correlation between the physicochemical parameters of the compounds investigated and their antibacterial activity (both against standard strains and clinical isolates). The beta-nitrostyrene compounds displayed a lower activity towards all the tested bacteria relative to the beta-methyl-beta-nitrostyrene analogues. This was observed particularly for the 3-hydroxy-4-methoxy-beta-methyl-beta-nitrostyrene (IVb) against the Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium). The SPAR results revealed the existence of a clear correlation between the redox potentials and the antibacterial activity of the series of beta-nitrostyrene derivatives under study.
Subject(s)
Anti-Bacterial Agents/chemistry , Styrenes/chemistry , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Electrochemistry , Gram-Positive Bacteria/drug effects , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Oxidation-Reduction , Structure-Activity Relationship , Styrenes/chemical synthesis , Styrenes/pharmacologyABSTRACT
In100, a new integron carrying a carbapenemase gene (bla(VIM-2)) associated with a carbenicillinase (blaP1b) and aminoglycoside resistance genes (aacA4 and aadA2), was detected in a Pseudomonas aeruginosa clinical isolate. The particular gene cassette organization of In100 seems to reflect the evolution of antibiotic usage in therapeutics.