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1.
J Antimicrob Chemother ; 78(9): 2185-2191, 2023 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-37473450

RESUMO

BACKGROUND: In recent years, an increasing number of linezolid-resistant enterococci (LRE) was recognized at the German National Reference Centre (NRC) for Enterococci. National guidelines on infection prevention recommend screening for LRE in epidemiologically linked hospital settings without referring to a reliable and rapid diagnostic method. Since 2020, CHROMAgar™ provide a chromogenic linezolid screening agar, LIN-R, suitable to simultaneously screen for linezolid-resistant staphylococci and enterococci. OBJECTIVES: To assess the applicability of CHROMAgar™ LIN-R in clinical settings for detecting LRE directly from patient material and to infer prevalence rates of LRE amongst German hospital patients. METHODS: During the 3-month trial period, clinical samples were plated on CHROMAgar™ LIN-R. Antimicrobial susceptibility testing was performed using VITEK2 or disc diffusion. At the NRC, linezolid resistance was determined by broth microdilution, multiplex-PCR for cfr/optrA/poxtA and by a restriction-based assay for 23S rDNA mutations. RESULTS: The 12 participating study sites used 13 963 CHROMAgar™ LIN-R plates during the study period. Of 442 presumptive LRE, 192 were confirmed by phenotypic methods. Of these, 161 were received by the NRC and 121 (75%) were verified as LRE. Most of LR-E. faecium 53/81 (65%) exhibited a 23S rRNA gene mutation as the sole resistance-mediating mechanism, whereas optrA constituted the dominant resistance trait in LR-E. faecalis [39/40 (98%)]. Prevalence of LRE across sites was estimated as 1% (ranging 0.18%-3.7% between sites). CONCLUSIONS: CHROMAgar™ LIN-R represents a simple and efficient LRE screening tool in hospital settings. A high proportion of false-positive results demands validation of linezolid resistance by a reference method.


Assuntos
Enterococcus faecium , Infecções por Bactérias Gram-Positivas , Humanos , Linezolida/farmacologia , Antibacterianos/farmacologia , Prevalência , Farmacorresistência Bacteriana/genética , Enterococcus/genética , Hospitais , Infecções por Bactérias Gram-Positivas/epidemiologia , Enterococcus faecium/genética , Testes de Sensibilidade Microbiana , Enterococcus faecalis
2.
Clin Microbiol Infect ; 29(2): 190-199, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35623578

RESUMO

OBJECTIVES: Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a widely used method for bacterial species identification. Incomplete databases and mass spectral quality (MSQ) still represent major challenges. Important proxies for MSQ are the number of detected marker masses, reproducibility, and measurement precision. We aimed to assess MSQs across diagnostic laboratories and the potential of simple workflow adaptations to improve it. METHODS: For baseline MSQ assessment, 47 diverse bacterial strains, which are challenging to identify by MALDI-TOF MS, were routinely measured in 36 laboratories from 12 countries, and well-defined MSQ features were used. After an intervention consisting of detailed reported feedback and instructions on how to acquire MALDI-TOF mass spectra, measurements were repeated and MSQs were compared. RESULTS: At baseline, we observed heterogeneous MSQ between the devices, considering the median number of marker masses detected (range = [2-25]), reproducibility between technical replicates (range = [55%-86%]), and measurement error (range = [147 parts per million (ppm)-588 ppm]). As a general trend, the spectral quality was improved after the intervention for devices, which yielded low MSQs in the baseline assessment as follows: for four out of five devices with a high measurement error, the measurement precision was improved (p-values <0.001, paired Wilcoxon test); for six out of ten devices, which detected a low number of marker masses, the number of detected marker masses increased (p-values <0.001, paired Wilcoxon test). DISCUSSION: We have identified simple workflow adaptations, which, to some extent, improve MSQ of poorly performing devices and should be considered by laboratories yielding a low MSQ. Improving MALDI-TOF MSQ in routine diagnostics is essential for increasing the resolution of bacterial identification by MALDI-TOF MS, which is dependent on the reproducible detection of marker masses. The heterogeneity identified in this external quality assessment (EQA) requires further study.


Assuntos
Bactérias , Laboratórios , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Reprodutibilidade dos Testes , Fluxo de Trabalho
3.
Int J Syst Evol Microbiol ; 71(12)2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34908520

RESUMO

An obligately anaerobic strain, designated as A2931T, was isolated from oropharyngeal abscess puncture fluid of a patient sampled during routine care at a hospital and further characterized both phenotypically, biochemically and genotypically. This Gram-negative rod-shaped bacterium was moderately saccharolytic and proteolytic. Phylogenetic analyses of full-length 16S rRNA gene and whole-genome sequences revealed it to be best placed in the genus Prevotella, but to be only comparatively distantly related to recognized species, with the closest relationship to Prevotella baroniae (average nucleotide identity and digital DNA-DNA hybridization values both well below the generally accepted thresholds). Strain A2931T had a genomic DNA G+C content of 47.7 mol%. Its most abundant cellular long-chain fatty acids were anteiso-C15 : 0, iso-C15 : 0 and C16 : 0. Taken together, this polyphasic data suggests strain A2931T to represent a novel species within the genus Prevotella, for which the name Prevotella illustrans sp. nov. is proposed. The type strain is A2931T (=DSM 108028T=CCOS 1232T=CCUG 72806T). Interestingly, we found strain A2931T to correspond to the oral taxon Prevotella HMT-820 in the Human Oral Microbiome Database, as supported by overall genome relatedness index analyses >99 %. Thus, our work not only closes one of the gaps of knowledge about hitherto unnamed species isolated from humans, but also will facilitate identification of this taxon both in the clinical microbiology context and in research alike.


Assuntos
Abscesso , Orofaringe/microbiologia , Filogenia , Prevotella/classificação , Abscesso/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Humanos , Prevotella/isolamento & purificação , Punções , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
4.
Int J Syst Evol Microbiol ; 71(10)2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34633923

RESUMO

Two isolates of a non-fermenting, Gram-negative bacterial strain were cultured from two throat swabs that were taken from a pair of twins during routine microbiological surveillance screening. As these isolates could not be unambiguously identified using routine diagnostic methods, whole genome sequencing was performed followed by phylogenetic analysis based on the rpoB gene sequence and by whole genome datasets. The two strains compose a separate branch within the clade formed by the Acinetobacter calcoaceticus-baumannii (ACB) complex with Acinetobacter pittii CIP 70.29T as the most closely related species. The average nucleotide identity compared to all other species of the ACB complex was below 94.2% and digital DNA-DNA hybridization values were less than 60%. Biochemical characteristics confirm affiliation to the ACB complex with some specific phenotypic differences. As a result of the described data, a new Acinetobacter species is introduced, for which the name Acinetobacter geminorum sp. nov. is proposed. The type strain is J00019T with a G+C DNA content of 38.8 mol% and it is deposited in the DSMZ Germany (DSM 111094T) and CCUG Sweden (CCUG 74625T).


Assuntos
Acinetobacter , Faringe , Filogenia , Acinetobacter/classificação , Acinetobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Genes Bacterianos , Humanos , Hibridização de Ácido Nucleico , Faringe/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
5.
Eur J Clin Microbiol Infect Dis ; 39(10): 2003, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32870443

RESUMO

Table 2 in the originally published article is not correct and is a duplicate of Table 3. The error happened during typesetting. The correct Table 2 is shown below.

6.
mSphere ; 5(4)2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32817379

RESUMO

Infections with multidrug-resistant bacteria often leave limited or no treatment options. The transfer of antimicrobial resistance genes (ARG) carrying plasmids between bacterial species by horizontal gene transfer represents an important mode of expansion of ARGs. Here, we demonstrate the application of Nanopore sequencing in a hospital setting for monitoring transfer and rapid evolution of antibiotic resistance plasmids within and across multiple species. In 2009, we experienced an outbreak with extensively multidrug-resistant Pseudomonas aeruginosa harboring the carbapenemase-encoding blaIMP-8 gene. In 2012, the first Citrobacter freundii and Citrobacter cronae strains harboring the same gene were detected. Using Nanopore and Illumina sequencing, we conducted comparative analysis of all blaIMP-8 bacteria isolated in our hospital over a 6-year period (n = 54). We developed the computational platform plasmIDent for Nanopore-based characterization of clinical isolates and monitoring of ARG transfer, comprising de novo assembly of genomes and plasmids, plasmid circularization, ARG annotation, comparative genome analysis of multiple isolates, and visualization of results. Using plasmIDent, we identified a 40-kb plasmid carrying blaIMP-8 in P. aeruginosa and C. freundii, verifying the plasmid transfer. Within C. freundii, the plasmid underwent further evolution and plasmid fusion, resulting in a 164-kb megaplasmid, which was transferred to C. cronae Multiple rearrangements of the multidrug resistance gene cassette were detected in P. aeruginosa, including deletions and translocations of complete ARGs. In summary, plasmid transfer, plasmid fusion, and rearrangement of the ARG cassette mediated the rapid evolution of opportunistic pathogens in our hospital. We demonstrated the feasibility of near-real-time monitoring of plasmid evolution and ARG transfer in clinical settings, enabling successful countermeasures to contain plasmid-mediated outbreaks.IMPORTANCE Infections with multidrug-resistant bacteria represent a major threat to global health. While the spread of multidrug-resistant bacterial clones is frequently studied in the hospital setting, surveillance of the transfer of mobile genetic elements between different bacterial species was difficult until recent advances in sequencing technologies. Nanopore sequencing technology was applied to track antimicrobial gene transfer in a long-term outbreak of multidrug-resistant Pseudomonas aeruginosa, Citrobacter freundii, and Citrobacter cronae in a German hospital over 6 years. We developed a novel computational pipeline, pathoLogic, which enables de novo assembly of genomes and plasmids, antimicrobial resistance gene annotation and visualization, and comparative analysis. Applying this approach, we detected plasmid transfer between different bacterial species as well as plasmid fusion and frequent rearrangements of the antimicrobial resistance gene cassette. This study demonstrated the feasibility of near-real-time tracking of plasmid-based antimicrobial resistance gene transfer in hospitals, enabling countermeasures to contain plasmid-mediated outbreaks.


Assuntos
Farmacorresistência Bacteriana Múltipla , Evolução Molecular , Sequenciamento por Nanoporos , Plasmídeos/genética , Análise de Sequência de DNA/métodos , Antibacterianos/farmacologia , Transferência Genética Horizontal , Genômica , Hospitais , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , beta-Lactamases/genética
7.
Int J Syst Evol Microbiol ; 70(8): 4576-4582, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32735207

RESUMO

A strain of an obligately anaerobic, Gram-stain-negative rod-shaped bacterium is described by phenotypical, biochemical and genotypical characterization. This strain A2879T was isolated from an abscess swab of a patient sampled during routine care at hospital. Phylogenetic analyses (full-length 16S rRNA gene and whole-genome sequence) revealed the strain to belong to the genus Prevotella, but to be distant from recognized species, with the closest relationship to Prevotella veroralis. Unambiguous identification also proved possible by MALDI-TOF MS. The genomic DNA G+C content was 41.5 mol%. Strain A2879T was moderately saccharolytic and proteolytic. The most abundant cellular long-chain fatty acids were anteiso-C15 : 0 and iso-C15 : 0. In view of these data, strain A2879T is considered to represent a novel species within the genus Prevotella, for which the name Prevotella vespertina sp. nov. is proposed. The type strain is A2879T (=DSM 108027T=CCOS 1233T=CCUG72808T). As this strain has been isolated from a clinical sample, it is considered relevant for human medicine and health in general, and in particular for the fields of clinical microbiology and infectious diseases. This description will enable routine and research laboratories alike to easily identify the novel taxon, allowing its role in the context of human health and disease or microbiota to be further elucidated.


Assuntos
Abscesso/microbiologia , Filogenia , Prevotella/classificação , Adulto , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Alemanha , Humanos , Masculino , Prevotella/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
8.
BMC Pediatr ; 20(1): 234, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32429874

RESUMO

BACKGROUND: Respiratory distress syndrome (RDS) is a frequent complication of premature birth. Treating RDS by continuous positive airway pressure and less invasive surfactant administration (LISA) may reduce bronchopulmonary dysplasia. Surfactant, however, can be inactivated by bacterial infection. Therefore, potential routes of microbe transmission into the airway are of interest. The aim of this study was to evaluate microbiological contamination of catheters used for LISA procedures and its association with postnatal age. METHODS: Catheter tips used for LISA procedures via the nasal route (LISA-n) in infants with RDS were placed into a sterile eSwab container directly after the procedure, cultured and examined for microbiological contamination. RESULTS: Interpretable results could be collected from 20 catheter tips. Four showed positive culture results (20%) with microbes potentially associated with the development of early onset neonatal sepsis. Risk of positive microbe detection increased with postnatal age (< 4 h: 10%; 4-18 h: 20%; > 18 h: 40%). CONCLUSIONS: In this pilot study, the risk of tracheal microbe transmission following the LISA-n procedure increased with postnatal age. Although the clinical relevance of this finding is unclear, earlier surfactant administration might reduce the risk of catheter contamination. TRIAL REGISTRATION NUMBER: Substudy of the registered Trial: feasibility study - Neofact: NCT04086095, www.ClinicalTrials.gov, September 11, 2019.


Assuntos
Surfactantes Pulmonares , Síndrome do Desconforto Respiratório do Recém-Nascido , Displasia Broncopulmonar/terapia , Catéteres , Pressão Positiva Contínua nas Vias Aéreas , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Projetos Piloto , Gravidez , Surfactantes Pulmonares/uso terapêutico , Síndrome do Desconforto Respiratório do Recém-Nascido/tratamento farmacológico , Tensoativos/uso terapêutico
9.
Int J Syst Evol Microbiol ; 70(5): 2998-3003, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32375941

RESUMO

Nine independent Gram-negative bacterial strains were isolated from rectal swabs or stool samples of immunocompromised patients from two different wards of a university hospital. All isolates were phylogenetically analysed based on their 16S rRNA gene sequence, housekeeping gene recN, multilocus sequence analysis of concatenated partial fusA, leuS, pyrG and rpoB sequences, and by whole genome sequencing data. The analysed strains of the new species cluster together and form a separate branch with Citrobacter werkmanii NBRC105721T as the most closely related species. An average nucleotide identity value of 95.9-96% and computation of digital DNA-DNA hybridization values separate the new species from all other type strains of the genus Citrobacter. Biochemical characteristics further delimit the isolates from closely related Citrobacter type strains. As a result of the described data, a new Citrobacter species is introduced, for which the name Citrobacter cronae sp. nov. is proposed. The type strain is Tue2-1T with a G+C DNA content of 52.2 mol%.


Assuntos
Citrobacter/classificação , Fezes/microbiologia , Filogenia , Reto/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Citrobacter/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Alemanha , Humanos , Hospedeiro Imunocomprometido , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
10.
Eur J Clin Microbiol Infect Dis ; 39(6): 1147-1157, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32020397

RESUMO

Fast identification of pathogens directly from positive blood cultures is of highest importance to supply an adequate therapy of bloodstream infections (BSI). There are several platforms providing molecular-based identification, detection of antimicrobial resistance genes, or even a full antimicrobial susceptibility testing (AST). Two of such test systems allowing rapid diagnostics were assessed in this study: The Biofire FilmArray® and the Genmark ePlex®, both fully automated test system with a minimum of hands-on time. Overall 137 BSI episodes were included in our study and compared to conventional culture-based reference methods. The FilmArray® is using one catridge including a panel for the most common bacterial and fungal BSI pathogens as well as selected resistance markers. The ePlex® offers three different cartridges for detection of Gram-positives, Gram-negatives, and fungi resulting in a broader panel including also rare pathogens, putative contaminants, and more genetic resistance markers. The FilmArray® and ePlex® were evaluated for all 137 BSI episodes with FilmArray® detecting 119 and ePlex® detecting 128 of these. For targets on the respective panel of the system, the FilmArray® generated a sensitivity of 98.9% with 100% specificity on Gram-positive isolates. The ePlex® system generated a sensitivity of 94.7% and a specificity of 90.7% on Gram-positive isolates. In each case, the two systems performed with 100% sensitivity and specificity for the detection of Gram-negative specimens covered by each panel. In summary, both evaluated test systems showed a satisfying overall performance for fast pathogen identification and are beneficial tools for accelerating blood culture diagnostics of sepsis patients.


Assuntos
Algoritmos , Técnicas de Diagnóstico Molecular/métodos , Sepse/diagnóstico , Bactérias/genética , Bactérias/isolamento & purificação , Hemocultura , Testes Diagnósticos de Rotina , Resistência Microbiana a Medicamentos/genética , Fungos/genética , Fungos/isolamento & purificação , Humanos , Técnicas de Diagnóstico Molecular/normas , Sensibilidade e Especificidade
11.
Int J Syst Evol Microbiol ; 69(12): 3933-3938, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31644420

RESUMO

A strain of an obligately anaerobic, Gram-stain-negative rod-shaped bacterium is described by phenotypical, biochemical and genotypical characterization. Strain A2672T was isolated from a wound of a patient sampled during routine care at hospital. Phylogenetic analysis was based on full-length 16S rRNA gene sequence analysis and revealed the strain to belong to the genus Prevotella, but to be distant from known species, with the closest relationship to Prevotella corporis. The genomic DNA G+C content was 44.0 mol%. Strain A2672T was moderately saccharolytic and proteolytic. The most abundant cellular long-chain fatty acids were anteiso-C15 : 0 and iso-C15 : 0. In view of these characteristics as well as whole-genome sequence analysis, strain A2672T is considered to represent a novel species within the genus Prevotella, for which the name Prevotella brunnea sp. nov. is proposed. The type strain is A2672T (=DSM 108033T=CCOS 1231T=CCUG 72809T).


Assuntos
Pé Diabético/microbiologia , Filogenia , Prevotella/classificação , Idoso , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Humanos , Masculino , Prevotella/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
12.
J Antimicrob Chemother ; 74(10): 2891-2894, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31302698

RESUMO

OBJECTIVES: To characterize a new variant of the FRI class A carbapenemase isolated from an MDR clinical Enterobacter cloacae isolate. METHODS: A carbapenem-resistant E. cloacae was isolated from a rectal swab from a patient in an ICU in Southern Germany. Various phenotypic tests confirmed production of a putative class A carbapenemase. The new bla gene variant, blaFRI-3, and its genetic environment were characterized by WGS. Biochemical characterization was performed by heterologous expression in Escherichia coli TOP10 and by purification of the enzyme with subsequent determination of its kinetic parameters. RESULTS: PCR and sequencing carried out for different class A carbapenemase genes confirmed the presence of a novel variant of blaFRI-1. The novel variant was named FRI-3 and exhibited 91%, 96% and 92% amino acid identity to FRI-1, FRI-2 and FRI-4, respectively. E. coli TOP10 expressing blaFRI-3 showed increased resistance to almost all ß-lactams. Comparing the catalytic behaviour of FRI-3 and FRI-1, it was shown that FRI-3 had the same substrate spectrum, but basically hydrolysed ß-lactams less efficiently than FRI-1. WGS data revealed that blaFRI-3 was located on a 111 kb plasmid. CONCLUSIONS: The biochemical characterization of FRI-3 illustrates that even a few differences in the amino acid sequence can lead to altered catalytic activities of ß-lactamases belonging to the same family.


Assuntos
Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacter cloacae/enzimologia , beta-Lactamases/genética , beta-Lactamases/metabolismo , Proteínas de Bactérias/classificação , Técnicas Bacteriológicas , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/metabolismo , Enterobacter cloacae/isolamento & purificação , Infecções por Enterobacteriaceae/microbiologia , Alemanha , Humanos , Hidrólise , Unidades de Terapia Intensiva , Reação em Cadeia da Polimerase , Reto/microbiologia , Análise de Sequência de DNA , beta-Lactamases/classificação
13.
Artigo em Inglês | MEDLINE | ID: mdl-30782988

RESUMO

Vancomycin-resistant Enterococcus faecium (VREfm) is a frequent cause of nosocomial outbreaks. In the second half of 2015, a sharp increase in the incidence of VREfm was observed at our university medical center. Next-generation sequencing (NGS) was used to analyze the first isolates of VREfm recovered from patients between 2010 and 2016 (n = 773) in order to decipher epidemiological change, outbreak dynamics, and possible transmission routes. VREfm isolates were analyzed using whole-genome sequencing followed by sequence type extraction and phylogenetic analysis. We examined epidemiological data, room occupancy data, and patient transferals and calculated an intensity score for patient-to-patient contact. Phylogenetic analysis revealed the presence of 38 NGS clusters and 110 single clones. The increase of VREfm was caused mainly by the expansion of two newly introduced NGS clusters, comprising VanB-type strains determined by multilocus sequence typing (MLST) as sequence type 80 (ST80) and ST117. By combining phylogenetic information with epidemiological data, intrahospital transmission could be demonstrated, however to a lesser extent than initially expected based solely on epidemiological data. The outbreak clones were continuously imported from other hospitals, suggesting a change in the epidemiological situation at a regional scale. By tracking intrahospital patient transferals, two major axes could be identified that contributed to the spread of VREfm within the hospital. NGS-based outbreak analysis revealed a dramatic change in the local and regional epidemiology of VREfm, emphasizing the role of health care networks in the spread of VREfm.


Assuntos
Antibacterianos/farmacologia , Vancomicina/farmacologia , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/genética , Genoma Bacteriano/genética , Alemanha , Humanos , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/genética
14.
BMC Genomics ; 18(1): 859, 2017 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-29126393

RESUMO

BACKGROUND: Pseudomonas putida is a Gram-negative, non-fermenting bacterium frequently encountered in various environmental niches. P. putida rarely causes disease in humans, though serious infections and outbreaks have been reported from time to time. Some have suggested that P. putida functions as an exchange platform for antibiotic resistance genes (ARG), and thus represents a serious concern in the spread of ARGs to more pathogenic organisms within a hospital. Though poorly understood, the frequency of ARG exchange between P. putida and the more virulent Pseudomonas aeruginosa and its clinical relevance are particularly important for designing efficient infection control strategies, such as deciding whether high-risk patients colonized with a multidrug resistant but typically low pathogenic P. putida strain should be contact isolated or not. RESULTS: In this study, 21,373 screening samples (stool, rectal and throat swab) were examined to determine the presence of P. putida in a high-risk group of haemato-oncology patients during a 28-month period. A total of 89 P. putida group strains were isolated from 85 patients, with 41 of 89 (46.1%) strains harbouring the metallo-beta-lactamase gene bla VIM. These 41 clinical isolates, plus 18 bla VIM positive environmental P. putida isolates, and 17 bla VIM positive P. aeruginosa isolates, were characterized by whole genome sequencing (WGS). We constructed a maximum-likelihood tree to separate the 59 bla VIM positive P. putida group strains into eight distinct phylogenetic clusters. Bla VIM-1 was present in 6 clusters while bla VIM-2 was detected in 4 clusters. Five P. putida group strains contained both, bla VIM-1 and bla VIM-2 genes. In contrast, all P. aeruginosa strains belonged to a single genetic cluster and contained the same ARGs. Apart from bla VIM-2 and sul genes, no other ARGs were shared between P. aeruginosa and P. putida. Furthermore, the bla VIM-2 gene in P. aeruginosa was predicted to be only chromosomally located. CONCLUSION: These data provide evidence that no exchange of comprehensive ARG harbouring mobile genetic elements had occurred between P. aeruginosa and P. putida group strains during the study period, thus eliminating the need to implement enhanced infection control measures for high-risk patients colonized with a bla VIM positiv P. putida group strains in our clinical setting.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Meio Ambiente , Transferência Genética Horizontal , Genômica , Pseudomonas aeruginosa/genética , Pseudomonas putida/genética , Humanos , Filogenia , Pseudomonas putida/efeitos dos fármacos , Pseudomonas putida/fisiologia
15.
J Clin Microbiol ; 55(7): 2116-2126, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28446572

RESUMO

Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli (n = 7) and multidrug-resistant Pseudomonas aeruginosa (n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h (P < 0.0001) and for AST by 40.39 h (P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.


Assuntos
Técnicas Bacteriológicas/métodos , Sangue/microbiologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/isolamento & purificação , Infecções por Bactérias Gram-Negativas/diagnóstico , Sepse/diagnóstico , Automação Laboratorial/métodos , Bactérias Gram-Negativas/classificação , Humanos , Sensibilidade e Especificidade , Fatores de Tempo
17.
Nature ; 535(7613): 511-6, 2016 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-27466123

RESUMO

The vast majority of systemic bacterial infections are caused by facultative, often antibiotic-resistant, pathogens colonizing human body surfaces. Nasal carriage of Staphylococcus aureus predisposes to invasive infection, but the mechanisms that permit or interfere with pathogen colonization are largely unknown. Whereas soil microbes are known to compete by production of antibiotics, such processes have rarely been reported for human microbiota. We show that nasal Staphylococcus lugdunensis strains produce lugdunin, a novel thiazolidine-containing cyclic peptide antibiotic that prohibits colonization by S. aureus, and a rare example of a non-ribosomally synthesized bioactive compound from human-associated bacteria. Lugdunin is bactericidal against major pathogens, effective in animal models, and not prone to causing development of resistance in S. aureus. Notably, human nasal colonization by S. lugdunensis was associated with a significantly reduced S. aureus carriage rate, suggesting that lugdunin or lugdunin-producing commensal bacteria could be valuable for preventing staphylococcal infections. Moreover, human microbiota should be considered as a source for new antibiotics.


Assuntos
Antibacterianos/metabolismo , Peptídeos Cíclicos/metabolismo , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus lugdunensis/metabolismo , Simbiose , Tiazolidinas/metabolismo , Animais , Antibacterianos/biossíntese , Portador Sadio/microbiologia , Modelos Animais de Doenças , Resistência Microbiana a Medicamentos , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Microbiota/fisiologia , Nariz/microbiologia , Sigmodontinae , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/patogenicidade
18.
Am J Obstet Gynecol ; 215(5): 608.e1-608.e7, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27342046

RESUMO

BACKGROUND: Preterm delivery is a leading cause of neonatal morbidity and death. It often results from chorioamnionitis, which is a complication of bacterial vaginosis. Probiotics are effective in the treatment of bacterial vaginosis in women who were not pregnant; studies in pregnant woman are missing. OBJECTIVE: The purpose of this study was to evaluate whether an oral probiotic food supplement supports the maintenance or restoration of a normal vaginal microbiota during pregnancy. STUDY DESIGN: We conducted a randomized, placebo-controlled, triple-blind, parallel group trial. Oral Lactobacillus rhamnosus GR-1and L reuteri RC-14 (109 colony-forming units) or placebo were administered for 8 weeks to women with <12 completed weeks of pregnancy. Participants were enrolled at Tuebingen University Hospital and 10 recruiting gynecologic practices. Vaginal swabs were taken before and after intervention and analyzed according to the Nugent scoring system. Telephone interviews were performed before and after intervention and after delivery. Primary outcome was the proportion of swabs with normal Nugent score (<4) after intervention, compared by Fisher's exact test in an intention-to-treat analysis. RESULTS: Three hundred twenty pregnant women were enrolled. Vaginal swabs were analyzed from 290 women before and 271 women after intervention. The proportion of normal vaginal microbiota decreased from 82.6 to 77.8% in the treatment group and from 79.1 to 74.3% in the placebo group, with no significant difference across groups after intervention (P=.297). CONCLUSION: Oral probiotics may be suitable for implementation in antenatal care but, as administered here, had no effect on vaginal health during mid gestation. Other application routes or probiotic preparations may be more effective in supporting vaginal microbiota during pregnancy.


Assuntos
Lacticaseibacillus rhamnosus , Limosilactobacillus reuteri , Microbiota/efeitos dos fármacos , Probióticos/farmacologia , Vagina/efeitos dos fármacos , Administração Oral , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Gravidez , Primeiro Trimestre da Gravidez , Adulto Jovem
19.
Int J Syst Evol Microbiol ; 66(8): 3005-3009, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27150727

RESUMO

A strain of obligately anaerobic, Gram-stain-negative and non-spore-forming rod-shaped bacterium was isolated from a human wound and characterized both phenotypically and genotypically. The strain was moderately saccharolytic and proteolytic. Phylogenetic analysis was based on full-length 16S rRNA gene sequence analysis and revealed the strain to represent a member of the genus Prevotella, but to be different from the described species, with the closest relationship to Prevotella bergensis and Prevotella multisaccharivorax. The genomic DNA G+C content was 43.2 mol%. The most abundant cellular long-chain fatty acids were 3-OH iso-C17 : 0, anteiso-C15 : 0 and iso-C15 : 0. In view of phenotypical and biochemical characteristics as well as gene sequencing, strain A1336T is considered to represent a novel species within the genus Prevotella, for which the name Prevotella colorans sp. nov. is proposed. The type strain is A1336T (=DSM 100333T =CCUG 67421T =CCOS 902T).


Assuntos
Filogenia , Prevotella/classificação , Ferimentos e Lesões/microbiologia , Idoso , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Humanos , Pigmentação , Prevotella/genética , Prevotella/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
20.
Infection ; 44(4): 513-20, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26861246

RESUMO

BACKGROUND: Individuals with cystic fibrosis (CF) receive antibiotics continuously throughout their entire life which leads to drug resistant microbial lung infections which are difficult to treat. Nitric oxide (NO) gas possesses antimicrobial activity against a wide variety of microorganisms in vitro, in vivo in animal models and a phase I study in healthy adults showed administration of intermittent 160 ppm NO to be safe. METHODS: We assessed feasibility and safety of inhaled NO in eight CF patients who received 160 ppm NO for 30 min, three times daily for 2 periods of 5 days. RESULTS: The NO treatment was safe and in none of the patients were serious drug-related adverse events observed which caused termination of the study. The intention-to-treat analysis revealed a significant mean reduction of the colony forming units of all bacteria and all fungi, while mean forced expiratory volume 1 s % predicted (FEV1) relative to baseline increased 17.3 ± 8.9 % (P = 0.012). CONCLUSIONS: NO treatment may improve the therapy of chronic microbial lung infections in CF patients, particularly concerning pathogens with intrinsic or acquired resistance to antibiotics.


Assuntos
Anti-Infecciosos/uso terapêutico , Fibrose Cística/complicações , Óxido Nítrico/uso terapêutico , Infecções Respiratórias/complicações , Infecções Respiratórias/tratamento farmacológico , Adulto , Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/efeitos adversos , Farmacorresistência Bacteriana , Farmacorresistência Fúngica , Estudos de Viabilidade , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Óxido Nítrico/administração & dosagem , Óxido Nítrico/efeitos adversos , Infecções Respiratórias/microbiologia
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