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1.
Int J Antimicrob Agents ; 55(3): 105905, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31991221

RESUMO

BACKGROUND: Limited treatment options complicate management of infections with New Delhi metallo-ß-lactamase (NDM)-producing organisms. The efficacy of combination therapy with meropenem (MEM) and cefmetazole (CMZ) was assessed against NDM-producing Enterobacteriaceae. MATERIALS AND METHODS: Twelve Escherichia coli clinical isolates harbouring blaNDM-1 and a positive control E. coli BAA-2469 harbouring blaNDM-1 were studied. Minimum inhibitory concentrations (MICs) of MEM, ertapenem (ERT) and CMZ were determined by broth microdilution. Checkerboard and time-kill assays were performed to confirm the in vitro efficacy of the MEM/CMZ combination. Scanning electron microscopy, kinetic studies and whole-genome sequence analysis were used to determine the antimicrobial resistance mechanisms. RESULTS: MICs of MEM, ERT and CMZ in monotherapy ranged from 8 to 32, 16 to 128, and 32 to 512 µg/mL, respectively. In the checkerboard assay, MEM/ERT resulted in no synergy, whereas MEM/CMZ showed a synergistic effect in all the tested isolates. Furthermore, the MIC of MEM in combination decreased by 2- to 8-fold compared with that of MEM alone. The time-kill study revealed a bactericidal effect in 4 of 13 isolates at 24 h. Scanning electron microscopy showed spheroidisation of the bacterial cell in the MEM/CMZ combination; this was not observed in single antibiotic conditions. Kinetic studies indicated CMZ was a better antagonist for NDM-1 than ERT. Whole-genome sequence analysis did not reveal any explainable differences between isolates susceptible and those non-susceptible to combination therapy. CONCLUSION: In vitro studies showed the potential effectiveness of MEM/CMZ combination therapy against NDM-producing organisms.


Assuntos
Antibacterianos/farmacologia , Cefmetazol/farmacologia , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/efeitos dos fármacos , Meropeném/farmacologia , Antibacterianos/uso terapêutico , Cefmetazol/uso terapêutico , Quimioterapia Combinada , Enterobacteriaceae/metabolismo , Infecções por Enterobacteriaceae/microbiologia , Ertapenem/farmacologia , Humanos , Meropeném/uso terapêutico , beta-Lactamases/biossíntese
2.
Nat Commun ; 10(1): 4889, 2019 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-31653840

RESUMO

Innate immune chemoreceptors of the formyl peptide receptor (Fpr) family are expressed by vomeronasal sensory neurons (VSNs) in the accessory olfactory system. Their biological function and coding mechanisms remain unknown. We show that mouse Fpr3 (Fpr-rs1) recognizes the core peptide motif f-MKKFRW that is predominantly present in the signal sequence of the bacterial protein MgrB, a highly conserved regulator of virulence and antibiotic resistance in Enterobacteriaceae. MgrB peptide can be produced and secreted by bacteria, and is selectively recognized by a subset of VSNs. Exposure to the peptide also stimulates VSNs in freely behaving mice and drives innate avoidance. Our data shows that Fpr3 is required for neuronal detection and avoidance of peptides derived from a conserved master virulence regulator of enteric bacteria.


Assuntos
Aprendizagem da Esquiva , Enterobacteriaceae/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Membrana/metabolismo , Receptores de Formil Peptídeo/metabolismo , Células Receptoras Sensoriais/metabolismo , Órgão Vomeronasal/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Camundongos , Receptores de Formil Peptídeo/genética , Órgão Vomeronasal/citologia
3.
PLoS Pathog ; 15(8): e1007703, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31381590

RESUMO

Necrotrophic plant pathogens acquire nutrients from dead plant cells, which requires the disintegration of the plant cell wall and tissue structures by the pathogen. Infected plants lose tissue integrity and functional immunity as a result, exposing the nutrient rich, decayed tissues to the environment. One challenge for the necrotrophs to successfully cause secondary infection (infection spread from an initially infected plant to the nearby uninfected plants) is to effectively utilize nutrients released from hosts towards building up a large population before other saprophytes come. In this study, we observed that the necrotrophic pathogen Dickeya dadantii exhibited heterogeneity in bacterial cell length in an isogenic population during infection of potato tuber. While some cells were regular rod-shape (<10µm), the rest elongated into filamentous cells (>10µm). Short cells tended to occur at the interface of healthy and diseased tissues, during the early stage of infection when active attacking and killing is occurring, while filamentous cells tended to form at a later stage of infection. Short cells expressed all necessary virulence factors and motility, whereas filamentous cells did not engage in virulence, were non-mobile and more sensitive to environmental stress. However, compared to the short cells, the filamentous cells displayed upregulated metabolic genes and increased growth, which may benefit the pathogens to build up a large population necessary for the secondary infection. The segregation of the two subpopulations was dependent on differential production of the alarmone guanosine tetraphosphate (ppGpp). When exposed to fresh tuber tissues or freestanding water, filamentous cells quickly transformed to short virulent cells. The pathogen adaptation of cell length heterogeneity identified in this study presents a model for how some necrotrophs balance virulence and vegetative growth to maximize fitness during infection.


Assuntos
Proteínas de Bactérias/metabolismo , Parede Celular/química , Guanosina Tetrafosfato/metabolismo , Interações Hospedeiro-Patógeno , Doenças das Plantas/microbiologia , Solanum tuberosum/microbiologia , Fatores de Virulência/metabolismo , Proteínas de Bactérias/genética , Enterobacteriaceae/metabolismo , Enterobacteriaceae/patogenicidade , Regulação Bacteriana da Expressão Gênica , Doenças das Plantas/imunologia , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/metabolismo , Virulência , Fatores de Virulência/genética
4.
South Med J ; 112(8): 438-443, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31375841

RESUMO

OBJECTIVES: Urinary tract infections (UTIs) caused by extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae are resistant to many conventional therapies, including third-generation cephalosporins. Carbapenems are considered first-line agents for ESBL infections, but their use is associated with increased multidrug resistance and should be reserved when absolutely necessary. Because of the increased rates of UTIs caused by ESBL-producing organisms and incidence of carbapenem resistance, safe and effective alternatives to carbapenems are needed. This study was conducted to evaluate the outcomes associated with the treatment of ESBL UTIs with noncarbapenem antibiotics. METHODS: A retrospective cohort study of adults with ESBL UTIs was conducted at a community hospital. Patients were categorized as those receiving definitive carbapenem therapy and those receiving definitive noncarbapenem therapy. Calculated measurements included infection-related mortality, length of hospital stay, and duration of definitive antibiotic therapy. Microbiological failure was assessed as a secondary outcome. Data on the safety of antibiotic therapy were not collected. P < 0.05 was considered significant. RESULTS: Fifty patients met inclusion criteria for the study, divided evenly between the two cohorts. No statistical differences were observed for length of hospital stay (P = 0.601), duration of therapy (P = 0.398), or rate of microbiological failure between the groups (P = 0.115). CONCLUSIONS: Noncarbapenems did not demonstrate significant differences compared with carbapenems in the treatment of adults with ESBL UTIs. In certain patient populations, noncarbapenems that demonstrate in vitro activity may be appropriate for UTIs caused by ESBL-producing organisms.


Assuntos
Antibacterianos/uso terapêutico , Farmacorresistência Bacteriana , Enterobacteriaceae/isolamento & purificação , Infecções Urinárias/tratamento farmacológico , beta-Lactamases/metabolismo , Idoso , Idoso de 80 Anos ou mais , Carbapenêmicos , Enterobacteriaceae/metabolismo , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Infecções Urinárias/microbiologia
5.
Chemosphere ; 237: 124452, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31376699

RESUMO

Pollution of the environment with chlorinated aromatic compounds is a problem of increasing importance, which has stimulated the search for efficient methods for the remediation of contaminated soil and water. Additionally, for better understanding of the significance of bioavailability to biodegradation, investigation of the cell surface properties is necessary. Hence, this study concerns the properties and possible application, in chlorotoluene removal, of three newly isolated environmental bacterial strains from the genera Pseudomonas, Raoultella and Rahnella. The results show the differences in the biochemical profiles of the isolated strains, their cellular fatty acid composition and their hemolytic properties. However, all three strains exhibit high biodegradation potential, degrading not less than 60% of each monochlorotoluene isomer in 21-day experiments. What is more, observations of changes in the cell surface properties indicate the possible adaptation mechanisms of the strains that enable efficient biodegradation of hydrophobic pollutants such as monochlorotoluenes.


Assuntos
Bactérias/metabolismo , Biodegradação Ambiental , Hidrocarbonetos Clorados/metabolismo , Bactérias/química , Enterobacteriaceae/química , Enterobacteriaceae/metabolismo , Pseudomonas/química , Pseudomonas/metabolismo , Rahnella/química , Rahnella/metabolismo , Microbiologia do Solo , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Tolueno/análise , Tolueno/metabolismo
6.
Drugs ; 79(14): 1529-1541, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31407238

RESUMO

Extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae are a major global public health concern. Presently, Escherichia coli with CTX-Ms are the most common species associated with global ESBLs; CTX-M-15 is the most frequent CTX-M worldwide and is followed by CTX-M-14, which is often found in South-East Asia. Recent surveillance studies showed that CTX-M-27 is emerging in certain parts of the world especially in Japan and Europe. The population structure of ESBL-producing E. coli is dominated globally by an high-risk clone named ST131. Escherichia coli ST131 belongs to three clades (A, B, and C) and three different subclades (C1, C1-M27, and C2). Clade C1-M27 is associated with blaCTX-M-27, and C2 with blaCTX-M-15. Recent whole genome sequencing studies have shown that clade C has evolved from clade B in a stepwise fashion, resulting in one of the most influential global antimicrobial resistance clones that has emerged during the 2000's. Other important E. coli clones that have been detected among ESBL producers include ST405, ST38, ST648, ST410, and ST1193. The INCREMENT project has shown that ertapenem is as effective as other carbapenems for treating serious infections due to ESBL-producing Enterobacteriaceae. The results of the MERINO open-label randomized controlled study has provided clear evidence that piperacillin-tazobactam should be avoided for targeted therapy of blood-stream infections due to ESBL-producing E. coli and K. pneumoniae, regardless of the patient population, source of infection, bacterial species, and susceptibility result of piperacillin-tazobactam. Research is still warranted to define the optimal therapy of less severe infections due to ESBL-producing Enterobactericeae.


Assuntos
Antibacterianos/farmacologia , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/efeitos dos fármacos , beta-Lactamases/metabolismo , Animais , Enterobacteriaceae/metabolismo , Humanos , Epidemiologia Molecular/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
7.
Subcell Biochem ; 92: 79-123, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31214985

RESUMO

The transport of small molecules across membranes is essential for the import of nutrients and other energy sources into the cell and, for the export of waste and other potentially harmful byproducts out of the cell. While hydrophobic molecules are permeable to membranes, ions and other small polar molecules require transport via specialized membrane transport proteins . The two major classes of membrane transport proteins are transporters and channels. With our focus here on porins-major class of non-specific diffusion channel proteins , we will highlight some recent structural biology reports and functional assays that have substantially contributed to our understanding of the mechanism that mediates uptake of small molecules, including antibiotics, across the outer membrane of Enterobacteriaceae . We will also review advances in the regulation of porin expression and porin biogenesis and discuss these pathways as new therapeutic targets.


Assuntos
Porinas/metabolismo , Antibacterianos/metabolismo , Transporte Biológico , Enterobacteriaceae/metabolismo , Porinas/biossíntese , Porinas/genética
8.
J Med Microbiol ; 68(8): 1189-1193, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31225790

RESUMO

PURPOSE: In an increasing number of cases the last therapeutic option for treatment of carbapenem-resistant Enterobacteriaceae is colistin. As the detection of colistin resistance is problematic and time-consuming, it is desirable to find a rapid and reliable test. The rapid polymyxin NP test developed by Nordmann et al. addresses this problem and has a sensitivity of 99.3  % and a specificity of 95.4  %, as described by the authors. METHODS: In this study, we aimed to evaluate the NP test and tested the effect of measuring the absorbance of the test with an enzyme-linked immunosorbent assay (ELISA) reader at 430 nm as an alternative objectified readout. We performed a study with 120 carbapenemase-producing Enterobacteriaceae isolates, including 40 colistin-resistant and 23 colistin-susceptible Klebsiella pneumoniae, 4 resistant and 23 susceptible Escherichia coli, and 20 susceptible and 10 resistant Enterobacter species, respectively. RESULTS: Our data showed lower values for sensitivity and specificity than previously, namely only 91  % and 70 %, respectively, due to visual inspection. Furthermore, the results revealed a weakness in the correct detection of colistin-susceptible Enterobacter species. With the measurement of the absorbance we optimized the results to prevent misinterpretations of weak or inconclusive colour changes and enhanced the accuracy and objectivity of the rapid polymyxin NP test results. CONCLUSION: We reinforced the rapid polymyxin NP test as a rapid and valuable tool for detecting colistin-resistant K. pneumoniae isolates, although false-positive results were obtained for several colistin-susceptible Enterobacter spp. By using the optimized method, we were able to increase the sensitivity and specificity values to 94  % and 95  %, respectively.


Assuntos
Antibacterianos/farmacologia , Colistina/farmacologia , Farmacorresistência Bacteriana , Enterobacteriaceae/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Polimixinas/farmacologia , Proteínas de Bactérias/metabolismo , Enterobacteriaceae/isolamento & purificação , Enterobacteriaceae/metabolismo , Infecções por Enterobacteriaceae/microbiologia , Ensaio de Imunoadsorção Enzimática , Humanos , Sensibilidade e Especificidade , beta-Lactamases/metabolismo
9.
Int J Food Microbiol ; 304: 106-118, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31176963

RESUMO

Nicaraguan cocoa bean fermentations of several single local cocoa varieties originating from the same region (North Highlands of Nicaragua, San Jose de Bocay/El Cuá) were compared to fermentations of blended cocoa varietals from other producing regions of the country (Waslala and Nueva Guinea) making use of High Throughput Sequencing techniques, metabolite target analysis and sensory evaluation of cocoa liquor samples. A succession of the important cocoa-related yeasts Hanseniaspora uvarum/opuntiae, Saccharomyces cerevisiae and/or Pichia kudriavzevii was seen for single varietals and Nueva Guinea fermentations, while Kazachstania humilis dominated the mid and end phase of the Waslala cocoa fermentations. Tatumella species (mainly Tatumella terrea and Tatumella punctata) predominated the bacterial community at the onset of all fermentations followed by unusually late (generally 2 days into the fermentations) appearance of Lactobacillus fermentum relative to fermentations in other parts of the World. Acetobacter spp. were the main acetic acid bacteria during all fermentations, but also Gluconobacter spp. were involved in some single-variety fermentations. All fermentations proved complete as determined by metabolite analysis with bean sucrose being fully depleted and pulp sugars exhausted after 48-72 h of fermentation. From an organoleptic point of view, all Nicaraguan cocoas of this study reflected fine fruity (citrus or berry-like) flavours with distinct herbal or caramel notes. Floral notes were associated with the cases where P. kudriavzevii was involved in the later stages of fermentation. Intense citrus/fruity character was related to high pulp and bean citrate concentrations. Off-notes were found in some over-fermented batches where Bacillus spp. was detected. No relation between cut-test results and organoleptic appreciation was seen.


Assuntos
Bactérias/metabolismo , Cacau/microbiologia , Chocolate/microbiologia , Fermentação/fisiologia , Fungos/metabolismo , Ácido Acético/metabolismo , Acetobacter/metabolismo , Bactérias/isolamento & purificação , Reatores Biológicos/microbiologia , Enterobacteriaceae/metabolismo , Fungos/isolamento & purificação , Gluconobacter/metabolismo , Hanseniaspora/metabolismo , Lactobacillus fermentum/metabolismo , Pichia/metabolismo , Saccharomyces cerevisiae/metabolismo
10.
Arch Microbiol ; 201(9): 1207-1217, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31190085

RESUMO

We examined how Raoultella ornithinolytica-ZK4 degraded pyrethroid pesticides within soil sediment from an abandoned pesticide plant. Lambda-cypermethrin and deltamethrin are two pyrethroid insecticides with high insecticidal activity and a wide range of applications. However, their increased use has raised concerns regarding toxicity and accumulation. We isolated a strain of ZK4 (Raoultella ornithinolytica-ZK4) from soil taken from a channel that surrounded a pesticide plant. We used enzyme localization to study degrading bacteria ZK4. The ZK4 strain underwent intracellular enzyme degradation. The degradation rates of lambda-cyhalothrin and deltamethrin were 55% and 53%, respectively. The optimum pH of the two kinds of pyrethroids in ZK4 was 6.5, and their optimum temperature was 37 °C. The intracellular degradation of the crude enzyme produced by the ZK4 strain had a pH of 6.0-8.0 and a temperature of 20-42 °C. The ZK4 strain genome contained 5310 genes with a total length of 4,864,494 bp. Sugar metabolism and exogenous chemical metabolism accounted for the largest proportion of metabolic activities. We used the clusters of orthologous groups (COG) alignment and found numbers for 4686 protein sequences, accounting for 88.25% of the total predicted protein. ZK4 degraded lambda-cyhalothrin and deltamethrin, and may serve as a reference for the preparation of future degrading microbial agents to assist with environmental restoration efforts.


Assuntos
Biodegradação Ambiental , Enterobacteriaceae/metabolismo , Inseticidas/metabolismo , Poluentes do Solo/metabolismo , Solo/química , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Nitrilos/metabolismo , Piretrinas/metabolismo , Temperatura Ambiente
11.
Emerg Microbes Infect ; 8(1): 857-865, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31169081

RESUMO

Ciprofloxacin resistance in Salmonella has been increasingly reported due to the emergence and dissemination of multiple Plasmid-Mediated Quinolone Resistance (PMQR) determinants, which are mainly located in non-conjugative plasmids or chromosome. In this study, we aimed to depict the molecular mechanisms underlying the rare phenomenon of horizontal transfer of ciprofloxacin resistance phenotype in Salmonella by conjugation experiments, S1-PFGE and complete plasmid sequencing. Two types of non-conjugative plasmids, namely an IncX1 type carrying a qnrS1 gene, and an IncH1 plasmid carrying the oqxAB-qnrS gene, both ciprofloxacin resistance determinants in Salmonella, were recovered from two Salmonella strains. Importantly, these non-conjugative plasmids could be fused with a novel Incl1 type conjugative helper plasmid, which could target insertion sequence (IS) elements located in the non-conjugative, ciprofloxacin-resistance-encoding plasmid through replicative transcription, eventually forming a hybrid conjugative plasmid transmissible among members of Enterobacteriaceae. Since our data showed that such conjugative helper plasmids are commonly detectable among clinical Salmonella strains, particularly S. Typhimurium, fusion events leading to generation and enhanced dissemination of conjugative ciprofloxacin resistance-encoding plasmids in Salmonella are expected to result in a sharp increase in the incidence of resistance to fluoroquinolone, the key choice for treating life-threatening Salmonella infections, thereby posing a serious public health threat.


Assuntos
Antibacterianos/farmacologia , Ciprofloxacino/farmacologia , Conjugação Genética , Farmacorresistência Bacteriana , Plasmídeos/genética , Salmonella/efeitos dos fármacos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/metabolismo , Humanos , Testes de Sensibilidade Microbiana , Plasmídeos/metabolismo , Salmonella/genética , Salmonella/metabolismo , Infecções por Salmonella/microbiologia
12.
Nucleic Acids Res ; 47(15): e88, 2019 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-31147705

RESUMO

Small non-coding RNAs (sRNAs) regulate numerous cellular processes in all domains of life. Several approaches have been developed to identify them from RNA-seq data, which are efficient for eukaryotic sRNAs but remain inaccurate for the longer and highly structured bacterial sRNAs. We present APERO, a new algorithm to detect small transcripts from paired-end bacterial RNA-seq data. In contrast to previous approaches that start from the read coverage distribution, APERO analyzes boundaries of individual sequenced fragments to infer the 5' and 3' ends of all transcripts. Since sRNAs are about the same size as individual fragments (50-350 nucleotides), this algorithm provides a significantly higher accuracy and robustness, e.g., with respect to spontaneous internal breaking sites. To demonstrate this improvement, we develop a comparative assessment on datasets from Escherichia coli and Salmonella enterica, based on experimentally validated sRNAs. We also identify the small transcript repertoire of Dickeya dadantii including putative intergenic RNAs, 5' UTR or 3' UTR-derived RNA products and antisense RNAs. Comparisons to annotations as well as RACE-PCR experimental data confirm the precision of the detected transcripts. Altogether, APERO outperforms all existing methods in terms of sRNA detection and boundary precision, which is crucial for comprehensive genome annotations. It is freely available as an open source R package on https://github.com/Simon-Leonard/APERO.


Assuntos
Algoritmos , Escherichia coli/genética , Genoma Bacteriano , RNA Bacteriano/genética , RNA Mensageiro/genética , Pequeno RNA não Traduzido/genética , Salmonella enterica/genética , Conjuntos de Dados como Assunto , Enterobacteriaceae/genética , Enterobacteriaceae/metabolismo , Escherichia coli/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Internet , RNA Antissenso/classificação , RNA Antissenso/genética , RNA Antissenso/metabolismo , RNA Bacteriano/classificação , RNA Bacteriano/metabolismo , RNA Mensageiro/classificação , RNA Mensageiro/metabolismo , Pequeno RNA não Traduzido/classificação , Pequeno RNA não Traduzido/metabolismo , Salmonella enterica/metabolismo , Análise de Sequência de RNA , Software
13.
EcoSal Plus ; 8(2)2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31187729

RESUMO

Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the bacterial cell has been examined for about two decades; typically, they are not randomly distributed, and their positioning depends on copy number and their mode of segregation. Low-copy-number plasmids promote their own stable inheritance in their bacterial hosts by encoding active partition systems, which ensure that copies are positioned in both halves of a dividing cell. High-copy plasmids rely on passive diffusion of some copies, but many remain clustered together in the nucleoid-free regions of the cell. Here we review plasmid localization and partition (Par) systems, with particular emphasis on plasmids from Enterobacteriaceae and on recent results describing the in vivo localization properties and molecular mechanisms of each system. Partition systems also cause plasmid incompatibility such that distinct plasmids (with different replicons) with the same Par system cannot be stably maintained in the same cells. We discuss how partition-mediated incompatibility is a consequence of the partition mechanism.


Assuntos
Enterobacteriaceae/genética , Plasmídeos/genética , Proteínas de Bactérias/genética , Enterobacteriaceae/metabolismo , Replicon
14.
Crit Care ; 23(1): 170, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088542

RESUMO

BACKGROUND: Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are disseminating worldwide leading to increased hospital length of stay and mortality in intensive care units (ICU). ESBL-E dissemination was first due to outbreaks in hospital settings which led to the implementation of systematic fecal carriage screening to improve hygiene procedures by contact precautions. ESBLs have since spread in the community, and the relevance of contact precautions is questioned. ESBL-E dissemination led to an overuse of carbapenems triggering the emergence of carbapenem-resistant Enterobacteriaceae. Empirical antimicrobial therapy based on ESBL-E fecal carriage has been proposed but is debated as it could increase the consumption of carbapenems among ESBL-E carriers without any clinical benefit. Finally, selective decontamination among ESBL-E fecal carriers is evoked to decrease the risk for subsequent ESBL-E infection, but its efficacy remains debated. We propose to systematically review the evidence to recommend or not such systematic ESBL-E fecal carriage screening in adult ICU. METHODS: Every article focusing on ESBL-E and ICU available on the MEDLINE database was assessed. Articles were included if focusing on cross-transmission, efficacy of hygiene procedures, link between ESBL-E colonization and infection or guidance of empirical therapy or selective decontamination efficacy. RESULTS: Among 330 articles referenced on PubMed, 39 abstracts were selected for full-text assessment and 25 studies were included. Systematic screening of ESBL-E fecal carriage to guide contact precautions do not seem to decrease the rate of ESBL-E cross-transmission. It has a very good negative predictive value for subsequent ESBL-E infections but a positive predictive value between 40 and 50% and so does not help to spare carbapenems. Cessation of ESBL-E carriage systematic screening could decrease the use of carbapenems in ICU without any clinical harm. Nevertheless, further studies are needed to validate these results from monocentric before-after study. Selective decontamination strategy applied to ESBL-E fecal carriers could be helpful, but available data are conflicting. CONCLUSION: Current knowledge lacks of high-quality evidence to strongly recommend in favor of or against a systematic ESBL-E fecal carriage screening policy for ICU patients in a non-outbreak situation. Further evaluation of selective decontamination or fecal microbiota transplantation among ESBL-E fecal carriers is needed.


Assuntos
Portador Sadio/diagnóstico , Fezes/microbiologia , Programas de Rastreamento/métodos , beta-Lactamases/análise , Adulto , Portador Sadio/fisiopatologia , Infecção Hospitalar/prevenção & controle , Enterobacteriaceae/metabolismo , Enterobacteriaceae/patogenicidade , Infecções por Enterobacteriaceae/diagnóstico , Infecções por Enterobacteriaceae/fisiopatologia , Infecções por Enterobacteriaceae/prevenção & controle , Feminino , Humanos , Unidades de Terapia Intensiva/organização & administração , Masculino , Programas de Rastreamento/tendências , Testes de Sensibilidade Microbiana/métodos , beta-Lactamases/efeitos adversos , beta-Lactamases/metabolismo
15.
Microb Drug Resist ; 25(8): 1182-1190, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31140920

RESUMO

Extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) are important causes of serious infections in intensive care unit (ICU). This study aimed to investigate the risk factors for intestinal carriage of ESBL-PE among patients admitted to ICU, subsequent ESBL-PE infections, and outcomes of these patients. This study prospectively collected rectal swabs from 215 ICU patients in Northern Thailand and ESBL-PE were isolated. A high prevalence of ESBL-PE carriage (134/215, 62.3%) at ICU admission was observed, with Escherichia coli representing the predominant organism (67.5%) followed by Klebsiella pneumoniae (19.4%). Multivariate logistic regression analysis identified chronic renal disease as the independent risk factor for ESBL-PE carriage (p = 0.009; adjusted odds ratio = 4.369; 95% confidence interval = 1.455-13.119). Among colonized patients, 2.2% (3/134) developed ESBL-PE infections during ICU stay. Phylogenetic analysis of E. coli (n = 108) showed that the predominant group was group A (38.0%), followed by groups B1 (17.6%), D (15.7%), B2 (14.8%), C (7.4%), and F (6.5%). Multilocus sequence typing analysis of the pathogenic groups B2, D, and F revealed 11 different sequence types (STs), with ST131 (n = 13) as the most prevalent, followed by ST648 (n = 5), ST38 (n = 4), ST393 (n = 3), and ST1193 (n = 3). These results are of concern since ESBL-PE may be a prerequisite for endogenous infections and potentially disseminate within the hospital. This is the first study describing ESBL-PE carriage among patients at ICU admission and subsequent ESBL-PE infections in Thailand.


Assuntos
Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/isolamento & purificação , beta-Lactamases/metabolismo , Antibacterianos/uso terapêutico , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/metabolismo , Infecções por Enterobacteriaceae/tratamento farmacológico , Fezes/microbiologia , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Testes de Sensibilidade Microbiana/métodos , Pessoa de Meia-Idade , Filogenia , Estudos Prospectivos , Fatores de Risco , Centros de Atenção Terciária , Tailândia
16.
Emerg Microbes Infect ; 8(1): 564-574, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30945610

RESUMO

Tigecycline is regarded as a last-resort treatment for carbapenem-resistant Enterobacteriaceae (CRE), however, the emergence of tigecycline heteroresistance has posted the therapeutic challenge to combat this "nightmare bacteria". The primary purpose of this study was to demonstrate the existence of tigecycline heteroresistance in carbapenem-resistant E. cloacae (TH-CRECL) and further to explore the epidemiological characteristics and underlying molecular mechanisms. Our study identified a relative low prevalence of carbapenem-resistant E. cloacae (CRECL) isolates, about 20.0% (28/140), as heteroresistance to tigecycline. Molecular genetic relatedness of these heteroresistant isolates were characterized epidemiologically sporadic. In addition, mechanistic analysis revealed that Phe-Arg-ß-naphthylamide (PAßN) significantly reversed tigecycline MIC levels of resistant colonies in heteroresistant strains, as primarily related to the marked overproduction of efflux pump genes acrAB and oqxAB, as well as overexpression of transcriptional regulators (soxS and ramA). Moreover, logistic regression analysis showed that previous fluoroquinolone therapy was identified as the only potential independent risk factor for the acquisition of TH-CRECL. Most importantly, our data indicated that patients with TH-CRECL infection might lead to a remarkably prolonged hospital stay and deterioration in functional status. These findings emphasized the necessity of timely detection and intervention of patients infected with TH-CRECL.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Infecções por Enterobacteriaceae/microbiologia , Enterobacteriaceae/efeitos dos fármacos , Idoso , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carbapenêmicos/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , China , Enterobacteriaceae/genética , Enterobacteriaceae/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tigeciclina/farmacologia
17.
Infect Dis Health ; 24(3): 124-133, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30928569

RESUMO

BACKGROUND: Treatment of ESBL- and AmpC-producing Enterobacteriaceae bacteremia is often complicated by lack of appropriate antibiotics. We aimed to determine the predictors of mortality and impact of empirical antibiotics. METHODS: A retrospective observational study was performed on consecutive adult cases of ESBL and AmpC bacteremia at the Alfred Hospital from 2014 through April 2018. RESULTS: Among 110 patients with ESBL (88.2%) and AmpC (14.5%) bacteremia episodes, 96.4% had comorbidities such as hematological malignancy (30%). Approximately 45% were on immunosuppressive drugs, while 69% had recent antibiotic exposure. Over 84% of bacteremias were hospital acquired or healthcare associated. Urinary tract was the main source of infection (40%) with E. coli being the commonest organism (66.4%). The isolates were least resistant to gentamicin (21.8%), which was often appropriately used in empirical therapy. About 34% of patients presented with severe sepsis or shock. The 30-day mortality rate was 20% with no correlation with inappropriate empirical antibiotics (52%). There was no significant mortality difference between carbapenem use in empirical and definitive therapy. Respiratory source [OR 11.77, 95% CI 1.30-106.85; p = 0.03], severe sepsis or shock [OR 5.17, 95% CI 1.37-19.55; p = 0.02] and inappropriate definitive therapy [OR 27.93, 95%CI 3.69-211.35; p = 0.001] were independent predictors for mortality. CONCLUSION: The choice and appropriateness of empirical therapy were not associated with mortality in ESBL and AmpC bacteremia. Prudent use of carbapenem is reasonable with gentamicin as alternative. Emphasis should be on prompt resuscitation in severe sepsis and early detection of ESBL and AmpC to facilitate appropriate switch to definitive therapy.


Assuntos
Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Proteínas de Bactérias/metabolismo , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/metabolismo , beta-Lactamases/metabolismo , Idoso , Bacteriemia/complicações , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Farmacorresistência Bacteriana , Enterobacteriaceae/efeitos dos fármacos , Infecções por Enterobacteriaceae/complicações , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
18.
Biochemistry ; 58(13): 1818-1830, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30821147

RESUMO

When subjected to harsh conditions such as low pH, pathogenic Escherichia coli can secrete colanic acid to establish a protective barrier between the organism and the acidic environment. The colanic acid consists of a six-sugar repeating unit polymer comprised of glucose, fucose, galactose, and glucuronic acid. The region of the E. coli genome that encodes colanic acid biosynthesis has been reported, and the first enzyme in the biosynthesis pathway has been biochemically characterized. However, the specific roles of the remaining genes required for colanic acid biosynthesis have not been identified. Here we report the in vitro reconstitution of the next six steps in the assembly of the colanic acid repeating unit. To do this, we have cloned and overexpressed each gene within the colanic acid biosynthesis operon. We then tested the activity of the protein product of these genes using high-performance liquid chromatography analysis and a fluorescent analogue of the isoprenoid anchor bactoprenyl diphospho-glucose as a starting substrate. To ensure that retention time changes were associated with varying sugar additions or modifications, we developed a liquid chromatography-mass spectrometry method for analysis of the products produced by each enzyme. We have identified the function of all but one encoded glycosyltransferase and have identified the function of two acetyltransferases. This work demonstrates the centrality of acetylation in the biosynthesis of colanic acid and provides insight into the activity of key proteins involved in the production of an important and highly conserved bacterial glycopolymer.


Assuntos
Proteínas de Bactérias/metabolismo , Vias Biossintéticas , Enterobacteriaceae/metabolismo , Glicosiltransferases/metabolismo , Polissacarídeos/metabolismo , Acetilação , Proteínas de Bactérias/genética , Clonagem Molecular , Enterobacteriaceae/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Glicosiltransferases/genética , Polissacarídeos/genética
19.
J Appl Microbiol ; 126(6): 1722-1728, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30884025

RESUMO

AIM: The aim of this study was to isolate potential molybdate-reducing bacteria to be used for bioremediation. METHODS AND RESULTS: Two molybdate-reducing bacteria (Mo1 and MoI) were isolated from polluted soil samples from Ismailia Canal, Egypt and Sallah Elddin Governorate, Iraq respectively. The isolates exhibited dark blue colonies when grown on solid medium containing sodium molybdate which indicated the reduction of molybdate to molybdenum (Mo) blue. The absorbance values at 865 nm were 0·743 ± 0·007 and 0·453 ± 0·005 for Mo1 and MoI respectively. The Mo blue produced showed characteristic absorption spectrum peak at 865 nm and a shoulder at 700 nm. The isolates were identified by 16S rRNA genes sequencing and were submitted to GenBank as Raoultella ornithinolytica strain Mo1 and Raoultella planticola strain MoI. The optimum conditions were glucose as electron donor, initial pH of 6 and incubation temperature of 30°C. Scanning electron micrographs were taken for both isolates in the presence and absence of molybdate source. CONCLUSION: To the best of our knowledge, this is the first recordation of molybdate reduction by Raoultella sp. isolated from Egypt and Iraq. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolated bacteria belonging to the Raoultella could be used in in situ bioremediation.


Assuntos
Enterobacteriaceae/metabolismo , Molibdênio/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , DNA Bacteriano/genética , Egito , Enterobacteriaceae/genética , Enterobacteriaceae/ultraestrutura , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Iraque , Molibdênio/química , Oxirredução , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Temperatura Ambiente
20.
Artigo em Inglês | MEDLINE | ID: mdl-30917983

RESUMO

The activity of mecillinam (amdinocillin) was assessed in Enterobacterales (n = 420) isolated from urine samples between 2016 and 2017. Mecillinam susceptibilities were 97.4% in Escherichia coli isolates (294/302), 89.7% in Klebsiella spp. isolates (52/58), and 93.3% in Proteus mirabilis isolates (28/30). Among extended-spectrum ß-lactamase (ESBL) producers, 95.2% (99/104) were mecillinam susceptible, including two OXA-48-producing Klebsiella pneumoniae isolates. In Enterobacter spp. and Citrobacter spp., MICs were low (MIC50 = 0.5 mg/liter). In conclusion, the activity of mecillinam was high in Enterobacterales, even among multidrug-resistant isolates.


Assuntos
Andinocilina/farmacologia , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/efeitos dos fármacos , Idoso , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Enterobacteriaceae/metabolismo , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Feminino , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Masculino , Testes de Sensibilidade Microbiana , Estudos Prospectivos , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/metabolismo , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia , beta-Lactamases/metabolismo
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