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1.
ACS Synth Biol ; 13(4): 1093-1099, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38593047

RESUMO

RNA synthetic biology tools have primarily been applied in E. coli; however, many other bacteria are of industrial and clinical significance. Thus, the multicolor fluorogenic aptamer Pepper was evaluated in both Gram-positive and Gram-negative bacteria. Suitable HBC-Pepper dye pairs were identified that give blue, green, or red fluorescence signals in the E. coli, Bacillus subtilis, and Salmonella enterica serovar Typhimurium (S. Typhimurium). Furthermore, we found that different RNA scaffolds have a drastic effect on in vivo fluorescence, which did not correlate with the in vitro folding efficiency. One such scaffold termed DF30-tRNA displays 199-fold greater fluorescence than the Pepper aptamer alone and permits simultaneous dual color imaging in live cells.


Assuntos
Aptâmeros de Nucleotídeos , RNA , Escherichia coli/genética , Antibacterianos , Bactérias Gram-Negativas/genética , Bactérias Gram-Positivas , Salmonella typhimurium/genética , Aptâmeros de Nucleotídeos/genética
2.
Front Public Health ; 12: 1376513, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38601497

RESUMO

Intensive care units (ICUs) are specialized environments dedicated to the management of critically ill patients, who are particularly susceptible to drug-resistant bacteria. Among these, carbapenem-resistant Gram-negative bacteria (CR-GNB) pose a significant threat endangering the lives of ICU patients. Carbapenemase production is a key resistance mechanism in CR-GNB, with the transfer of resistance genes contributing to the extensive emergence of antimicrobial resistance (AMR). CR-GNB infections are widespread in ICUs, highlighting an urgent need for prevention and control measures to reduce mortality rates associated with CR-GNB transmission or infection. This review provides an overview of key aspects surrounding CR-GNB within ICUs. We examine the mechanisms of bacterial drug resistance, the resistance genes that frequently occur with CR-GNB infections in ICU, and the therapeutic options against carbapenemase genotypes. Additionally, we highlight crucial preventive measures to impede the transmission and spread of CR-GNB within ICUs, along with reviewing the advances made in the field of clinical predictive modeling research, which hold excellent potential for practical application.


Assuntos
Carbapenêmicos , Infecções por Bactérias Gram-Negativas , Humanos , Carbapenêmicos/farmacologia , Carbapenêmicos/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias Gram-Negativas/genética , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/prevenção & controle , Infecções por Bactérias Gram-Negativas/microbiologia , Unidades de Terapia Intensiva
3.
BMC Infect Dis ; 24(1): 378, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38582858

RESUMO

INTRODUCTION: Carbapenem-resistant gram-negative bacilli are a worldwide concern because of high morbidity and mortality rates. Additionally, the increasing prevalence of these bacteria is dangerous. To investigate the extent of antimicrobial resistance and prioritize the utility of novel drugs, we evaluated the molecular characteristics and antimicrobial susceptibility profiles of carbapenem-resistant Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii in Ecuador in 2022. METHODS: Ninety-five clinical isolates of carbapenem non-susceptible gram-negative bacilli were collected from six hospitals in Ecuador. Carbapenem resistance was confirmed with meropenem disk diffusion assays following Clinical Laboratory Standard Institute guidelines. Carbapenemase production was tested using a modified carbapenemase inactivation method. Antimicrobial susceptibility was tested with a disk diffusion assay, the Vitek 2 System, and gradient diffusion strips. Broth microdilution assays were used to assess colistin susceptibility. All the isolates were screened for the blaKPC, blaNDM, blaOXA-48, blaVIM and blaIMP genes. In addition, A. baumannii isolates were screened for the blaOXA-23, blaOXA-58 and blaOXA-24/40 genes. RESULTS: Carbapenemase production was observed in 96.84% of the isolates. The blaKPC, blaNDM and blaOXA-48 genes were detected in Enterobacterales, with blaKPC being predominant. The blaVIM gene was detected in P. aeruginosa, and blaOXA-24/40 predominated in A. baumannii. Most of the isolates showed co-resistance to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole. Both ceftazidime/avibactam and meropenem/vaborbactam were active against carbapenem-resistant gram-negative bacilli that produce serin-carbapenemases. CONCLUSION: The epidemiology of carbapenem resistance in Ecuador is dominated by carbapenemase-producing K. pneumoniae harbouring blaKPC. Extensively drug resistant (XDR) P. aeruginosa and A. baumannii were identified, and their identification revealed the urgent need to implement strategies to reduce the dissemination of these strains.


Assuntos
Carbapenêmicos , beta-Lactamases , Humanos , Carbapenêmicos/farmacologia , Meropeném , Epidemiologia Molecular , Equador/epidemiologia , Testes de Sensibilidade Microbiana , beta-Lactamases/genética , Proteínas de Bactérias/genética , Antibacterianos/farmacologia , Bactérias Gram-Negativas/genética , Klebsiella pneumoniae/genética , Pseudomonas aeruginosa/genética
4.
Microbiology (Reading) ; 170(3)2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38450586

RESUMO

Lipopolysaccharide (LPS) is a fundamental tripartite glycolipid found on the surface of nearly all Gram-negative bacteria. It acts as a protective shield for the bacterial cell and is a potent agonist of the innate immune system. This primer serves to introduce the basic properties of LPS, its function in bacterial physiology and pathogenicity, and its use as a therapeutic target.


Assuntos
Bactérias Gram-Negativas , Lipopolissacarídeos , Bactérias Gram-Negativas/genética
5.
Nat Commun ; 15(1): 2758, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38553439

RESUMO

Hospital surfaces can harbour bacterial pathogens, which may disseminate and cause nosocomial infections, contributing towards mortality in low- and middle-income countries (LMICs). During the BARNARDS study, hospital surfaces from neonatal wards were sampled to assess the degree of environmental surface and patient care equipment colonisation by Gram-negative bacteria (GNB) carrying antibiotic resistance genes (ARGs). Here, we perform PCR screening for extended-spectrum ß-lactamases (blaCTX-M-15) and carbapenemases (blaNDM, blaOXA-48-like and blaKPC), MALDI-TOF MS identification of GNB carrying ARGs, and further analysis by whole genome sequencing of bacterial isolates. We determine presence of consistently dominant clones and their relatedness to strains causing neonatal sepsis. Higher prevalence of carbapenemases is observed in Pakistan, Bangladesh, and Ethiopia, compared to other countries, and are mostly found in surfaces near the sink drain. Klebsiella pneumoniae, Enterobacter hormaechei, Acinetobacter baumannii, Serratia marcescens and Leclercia adecarboxylata are dominant; ST15 K. pneumoniae is identified from the same ward on multiple occasions suggesting clonal persistence within the same environment, and is found to be identical to isolates causing neonatal sepsis in Pakistan over similar time periods. Our data suggests persistence of dominant clones across multiple time points, highlighting the need for assessment of Infection Prevention and Control guidelines.


Assuntos
Países em Desenvolvimento , Sepse Neonatal , Recém-Nascido , Humanos , beta-Lactamases/genética , Proteínas de Bactérias/genética , Hospitais , Antibacterianos/farmacologia , Klebsiella pneumoniae/genética , Bactérias Gram-Negativas/genética , Testes de Sensibilidade Microbiana
6.
Methods Mol Biol ; 2778: 367-381, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38478289

RESUMO

Biogenesis of the outer membrane (OM) of Gram-negative bacteria involves two processes essential for growth, that is, the insertion of ß-barrel outer membrane proteins (OMPs) by the Bam complex and the assembly of the LPS-containing outer leaflet of the OM by the LptD/E complex from the Lpt pathway. These processes have only recently gained attention as targets for antimicrobial drugs. Our laboratory has developed a simple screening tool to identify compounds that target processes that disrupt the biogenesis of the cell envelope, among which the activity of the Bam complex. The tool is based on the observation that such a disruption triggers cell envelope stress response systems, such as the σE, Rcs, and Cpx responses. In essence, specific stress-responsive promoters are fused to a gene encoding a bright fluorescent protein to serve as a panel of easy-to-monitor stress reporter plasmids. Using these plasmids, compounds triggering these stress systems and, therefore, putatively disrupting the biogenesis of the cell envelope can be identified by the nature and kinetics of the induced stress responses. We describe here the use of the stress reporter plasmids in high-throughput phenotypic screening using multi-well plates.


Assuntos
Proteínas de Escherichia coli , Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Celular/metabolismo , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/metabolismo
7.
Mol Genet Genomics ; 299(1): 26, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453747

RESUMO

Currently, there are several protocols to extract bacterial DNA based on different principles. However, the quantity and the quality of the DNA obtained by each method are highly variable and microorganism dependent. In most of these classical crude methods, highly toxic and hazardous organic solvents such as phenol and chloroform are used for deproteinization, whereas in certain protocols, expensive enzymes including RNases and Proteinases are used. This study was designed to introduce a simple, rapid, inexpensive and effective genomic DNA isolation procedure for Gram-negative bacteria, without the usage of toxic chemicals and costly enzymes. This novel method was compared with another classical method known as the salting-out method, which uses proteinase-K. Concentration and yield of the extracted DNA were determined by gel electrophoresis by comparing the gel band intensity of the sample DNA to that of a DNA quantitation standard and by the Quantus™ fluorometer. According to the results, the yield of extracted DNA was higher in the novel method compared to the salting-out method. Moreover, the entire process was accomplished in less than 2 h with the novel method. Purity and integrity of extracted genomic DNA by both methods were similar. In addition, the quality of DNA was determined using Multicopy Associated Filamentation (MAF) gene amplification by polymerase chain reaction (PCR). Thus, the described technique is non-toxic, less time and fund consuming, efficient and a well-suited method for routine DNA isolation from Gram negative bacteria.


Assuntos
DNA , Bactérias Gram-Negativas , DNA Bacteriano/genética , Bactérias Gram-Negativas/genética , Reação em Cadeia da Polimerase , Cloreto de Sódio , Genômica
8.
Appl Environ Microbiol ; 90(4): e0235123, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38517167

RESUMO

In rice paddies, soil and plant-derived organic matter are degraded anaerobically to methane (CH4), a powerful greenhouse gas. The highest rate of methane emission occurs during the reproductive stage of the plant when mostly dicarboxylic acids are exudated by the roots. The emission of methane at this stage depends largely on the cooperative interaction between dicarboxylic acid-fermenting bacteria and methanogenic archaea in the rhizosphere. The fermentation of tartrate, one of the major acids exudated, has been scarcely explored in rice paddy soils. In this work, we characterized an anaerobic consortium from rice paddy soil composed of four bacterial strains, whose principal member (LT8) can ferment tartrate, producing H2 and acetate. Tartrate fermentation was accelerated by co-inoculation with a hydrogenotrophic methanogen. The assembled genome of LT8 possesses a Na+-dependent oxaloacetate decarboxylase and shows that this bacterium likely invests part of the H2 produced to reduce NAD(P)+ to assimilate C from tartrate. The phylogenetic analysis of the 16S rRNA gene, the genome-based classification as well as the average amino acid identity (AAI) indicated that LT8 belongs to a new genus within the Sporomusaceae family. LT8 shares a few common features with its closest relatives, for which tartrate degradation has not been described. LT8 is limited to a few environments but is more common in rice paddy soils, where it might contribute to methane emissions from root exudates.IMPORTANCEThis is the first report of the metabolic characterization of a new anaerobic bacterium able to degrade tartrate, a compound frequently associated with plants, but rare as a microbial metabolite. Tartrate fermentation by this bacterium can be coupled to methanogenesis in the rice rhizosphere where tartrate is mainly produced at the reproductive stage of the plant, when the maximum methane rate emission occurs. The interaction between secondary fermentative bacteria, such as LT8, and methanogens could represent a fundamental step in exploring mitigation strategies for methane emissions from rice fields. Possible strategies could include controlling the activity of these secondary fermentative bacteria or selecting plants whose exudates are more difficult to ferment.


Assuntos
Euryarchaeota , Oryza , Solo/química , Oryza/microbiologia , Fermentação , Tartaratos/metabolismo , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Filogenia , Composição de Bases , Análise de Sequência de DNA , Bactérias , Bactérias Anaeróbias/metabolismo , Euryarchaeota/metabolismo , Firmicutes/metabolismo , Bactérias Gram-Negativas/genética , Metano/metabolismo
9.
Ann Clin Microbiol Antimicrob ; 23(1): 10, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38302964

RESUMO

OBJECTIVE: This study aims to identify the most effective diagnostic method for distinguishing pathogenic and non-pathogenic Gram-negative bacteria (GNB) in suspected pneumonia cases using metagenomic next-generation sequencing (mNGS) on bronchoalveolar lavage fluid (BALF) samples. METHODS: The effectiveness of mNGS was assessed on BALF samples collected from 583 patients, and the results were compared with those from microbiological culture and final clinical diagnosis. Three interpretational approaches were evaluated for diagnostic accuracy. RESULTS: mNGS outperformed culture significantly. Among the interpretational approaches, Clinical Interpretation (CI) demonstrated the best diagnostic performance with a sensitivity of 87.3%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 98.3%. CI's specificity was significantly higher than Simple Interpretation (SI) at 37.9%. Additionally, CI excluded some microorganisms identified as putative pathogens by SI, including Haemophilus parainfluenzae, Haemophilus parahaemolyticus, and Klebsiella aerogenes. CONCLUSION: Proper interpretation of mNGS data is crucial for accurately diagnosing respiratory infections caused by GNB. CI is recommended for this purpose.


Assuntos
Infecções Respiratórias , Humanos , Infecções Respiratórias/diagnóstico , Sequenciamento de Nucleotídeos em Larga Escala , Bactérias Gram-Negativas/genética , Metagenômica , Sensibilidade e Especificidade , Líquido da Lavagem Broncoalveolar
10.
Appl Microbiol Biotechnol ; 108(1): 191, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38305904

RESUMO

Bacterial degradation of natural rubber (NR) in an oxic environment is initiated by oxidative cleavage of double bonds in the NR-carbon backbone and is catalyzed by extracellular haem-containing rubber oxygenases. NR-cleavage products of sufficiently low molecular mass are taken up by the cells and metabolized for energy and biomass formation. Gram-negative and Gram-positive NR-degrading bacteria (usually) employ different types of rubber oxygenases such as RoxA and/or RoxB (most Gram-negative NR-degraders) or latex clearing protein Lcp (most Gram-positive NR-degraders). In order to find novel orthologues of Rox proteins, we have revisited databases and provide an update of Rox-like proteins. We describe the putative evolution of rubber oxygenases and confirm the presence of a third subgroup of Rox-related proteins (RoxCs), the biological function of which remains, however, unclear. We summarize the knowledge on the taxonomic position of Steroidobacter cummioxidans 35Y and related species. Comparison of genomic and biochemical features of strain 35Y with other species of the genus Steroidobacter suggests that strain 35Y represents a species of a novel genus for which the designation Aurantibaculum gen. nov. is proposed. A short summary on the capabilities of NR-degrading consortia, that could be superior in biotechnological applications compared to pure cultures, is also provided. KEY POINTS: • Three types of rubber oxygenases exist predominantly in Gram-negative microbes • S. cummioxidans 35Y contains RoxA and RoxB which are superior in activity • S. cummioxidans 35Y represents a species of a novel genus.


Assuntos
Oxigenases , Borracha , Borracha/metabolismo , Oxigenases/metabolismo , Proteínas de Bactérias/metabolismo , Látex/metabolismo , Bactérias Gram-Negativas/genética , Bactérias Gram-Negativas/metabolismo
11.
mSphere ; 9(2): e0063123, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38299856

RESUMO

Gregory Harrison is a bacteriologist researching essential pathways in bacteria as potential therapeutic targets. In this mSphere of Influence article, he reflects on a series of studies that employ complementary genetic approaches to define the crucial role of AsmA-family proteins in transporting phospholipids between the inner and outer membranes of Gram-negative bacteria. The authors of these three studies identify this family of lipid transporters through the means of bacterial genetics, answering a long-standing question in bacterial physiology, and serving as a reminder that a well-designed genetic strategy can go a long way in uncovering new biology.


Assuntos
Bactérias Gram-Negativas , Proteínas de Membrana Transportadoras , Transporte Biológico , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Bactérias Gram-Negativas/genética
12.
Environ Microbiol Rep ; 16(1): e13232, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38308519

RESUMO

Temperature significantly impacts bacterial physiology, metabolism and cell chemistry. In this study, we analysed lipids and the total cellular biochemical profile of 74 fast-growing Antarctic bacteria grown at different temperatures. Fatty acid diversity and temperature-induced alterations aligned with bacterial classification-Gram-groups, phylum, genus and species. Total lipid content, varied from 4% to 19% of cell dry weight, was genus- and species-specific. Most bacteria increased lipid content at lower temperatures. The effect of temperature on the profile was complex and more species-specific, while some common for all bacteria responses were recorded. Gram-negative bacteria adjusted unsaturation and acyl chain length. Gram-positive bacteria adjusted methyl branching (anteiso-/iso-), chain length and unsaturation. Fourier transform infrared spectroscopy analysis revealed Gram-, genus- and species-specific changes in the total cellular biochemical profile triggered by temperature fluctuations. The most significant temperature-related alterations detected on all taxonomy levels were recorded for mixed region 1500-900 cm-1 , specifically the band at 1083 cm-1 related to phosphodiester groups mainly from phospholipids (for Gram-negative bacteria) and teichoic/lipoteichoic acids (for Gram-positive bacteria). Some changes in protein region were detected for a few genera, while the lipid region remained relatively stable despite the temperature fluctuations.


Assuntos
Ácidos Graxos , Lipídeos de Membrana , Temperatura , Lipídeos de Membrana/análise , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Regiões Antárticas , Ácidos Graxos/metabolismo , Bactérias/genética , Bactérias/metabolismo , Bactérias Gram-Negativas/genética
13.
BMC Microbiol ; 24(1): 64, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38373913

RESUMO

BACKGROUND: Multi-drug-resistant organisms (MDROs) in gram-negative bacteria have caused a global epidemic, especially the bacterial resistance to carbapenem agents. Plasmid is the common vehicle for carrying antimicrobial resistance genes (ARGs), and the transmission of plasmids is also one of the important reasons for the emergence of MDROs. Different incompatibility group plasmid replicons are highly correlated with the acquisition, dissemination, and evolution of resistance genes. Based on this, the study aims to identify relevant characteristics of various plasmids and provide a theoretical foundation for clinical anti-infection treatment. METHODS: 330 gram-negative strains with different antimicrobial phenotypes from a tertiary hospital in Henan Province were included in this study to clarify the difference in incompatibility group plasmid replicons. Additionally, we combined the information from the PLSDB database to elaborate on the potential association between different plasmid replicons and ARGs. The VITEK mass spectrometer was used for species identification, and the VITEK-compact 2 automatic microbial system was used for the antimicrobial susceptibility test (AST). PCR-based replicon typing (PBRT) detected the plasmid profiles, and thirty-three different plasmid replicons were determined. All the carbapenem-resistant organisms (CROs) were tested for the carbapenemase genes. RESULTS: 21 plasmid replicon types were detected in this experiment, with the highest prevalence of IncFII, IncFIB, IncR, and IncFIA. Notably, the detection rate of IncX3 plasmids in CROs is higher, which is different in strains with other antimicrobial phenotypes. The number of plasmid replicons they carried increased with the strain resistance increase. Enterobacterales took a higher number of plasmid replicons than other gram-negative bacteria. The same strain tends to have more than one plasmid replicon type. IncF-type plasmids tend to be associated with MDROs. Combined with PLSDB database analysis, IncFII and IncX3 are critical platforms for taking blaKPC-2 and blaNDM. CONCLUSIONS: MDROs tend to carry more complex plasmid replicons compared with non-MDROs. The plasmid replicons that are predominantly prevalent and associated with ARGs differ in various species. The wide distribution of IncF-type plasmids and their close association with MDROs should deserve our attention. Further investigation into the critical role of plasmids in the carriage, evolution, and transmission of ARGs is needed.


Assuntos
Antibacterianos , Anti-Infecciosos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Plasmídeos/genética , beta-Lactamases/genética , Bactérias Gram-Negativas/genética , Carbapenêmicos/farmacologia , Fenótipo , Replicon , Testes de Sensibilidade Microbiana , Klebsiella pneumoniae/genética
14.
Int J Mol Sci ; 25(2)2024 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-38279257

RESUMO

Early and accurate diagnoses of pathogenic microorganisms is essential to correctly identify diseases, treating infections, and tracking disease outbreaks associated with microbial infections, to develop precautionary measures that allow a fast and effective response in epidemics and pandemics, thus improving public health. Aptamers are a class of synthetic nucleic acid molecules with the potential to be used for medical purposes, since they can be directed towards any target molecule. Currently, the use of aptamers has increased because they are a useful tool in the detection of specific targets. We present a brief review of the use of aptamers to detect and identify bacteria or even some toxins with clinical importance. This work describes the advances in the technology of aptamers, with the purpose of providing knowledge to develop new aptamers for diagnoses and treatment of different diseases caused by infectious microorganisms.


Assuntos
Aptâmeros de Nucleotídeos , Doenças Transmissíveis , Humanos , Técnica de Seleção de Aptâmeros , Bactérias Gram-Negativas/genética , Bactérias
15.
BMC Infect Dis ; 24(1): 141, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38287256

RESUMO

BACKGROUND: Gram-negative bacilli are the most common etiological agents responsible for urinary tract infections. The prevalence of antibiotic resistance in Gram-negative bacilli is increasing at a rapid pace globally, which is constraining the available choices for UTI treatment. The objectives of this study are to identify the most common causal organisms of urinary tract infections (UTIs), and to determine their drug resistance patterns. MATERIALS AND METHODS: This was a cross-sectional hospital-based study conducted at El-Amal Hospital, Bahri Teaching Hospital, and Al-Baraha Hospital, Khartoum State, from March to October 2022. Urine samples from patients suspected to have UTI were collected, and patients with confirmed UTI by laboratory investigations and yielded culture growth were enrolled. Antibiotic sensitivity testing and PCR testing of the blaTEM, blaSHV, and blaCTX-M genes were done. RESULTS: This study included 50 patients with UTI out of 229 suspected patients (21.8%). The most prominent group of patients was older than 60 years (40%); the majority were females (70%). Escherichia coli was the most prevalent isolated organism (50%), followed by Klebsiella oxytoca (24%), Klebsiella pneumoniae (20%), Pseudomonas aeruginosa (4%), and Citrobacter freundii (2%). A small percentage of organisms were resistant to colistin (17%). However, 77% were resistant to amikacin, 97.6% to cefotaxime, 96.8% to ceftazidime, 97.6% to ceftriaxone, 96.8% to cefixime, 87.6% to ciprofloxacin, 88.4% to gentamycin, 62% to imipenem, 67.6% to meropenem, 87.6% to norfloxacin, and 95.6% to trimethoprim. The overall resistance of isolated gram-negative organisms was 81%. The most prevalent gene for the resistance was blaTEM (100%), followed by blaCTX-M (94%), and then blaSHV (84%). CONCLUSION: Escherichia coli and Klebsiella species were the most commonly isolated uropathogens in this study, and the majority were highly resistant to most of the antimicrobial agents tested. Resistance genes blaTEM, blaCTX-M, and blaSHV are very common in uropathogens.


Assuntos
Escherichia coli , Infecções Urinárias , Feminino , Humanos , Masculino , Estudos Transversais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/epidemiologia , Bactérias Gram-Negativas/genética , Resistência Microbiana a Medicamentos , Hospitais de Ensino , Testes de Sensibilidade Microbiana , beta-Lactamases/genética
16.
Nucleic Acids Res ; 52(4): e19, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38180826

RESUMO

A synthetic biology toolkit, exploiting clustered regularly interspaced short palindromic repeats (CRISPR) and modified CRISPR-associated protein (Cas) base-editors, was developed for genome engineering in Gram-negative bacteria. Both a cytidine base-editor (CBE) and an adenine base-editor (ABE) have been optimized for precise single-nucleotide modification of plasmid and genome targets. CBE comprises a cytidine deaminase conjugated to a Cas9 nickase from Streptococcus pyogenes (SpnCas9), resulting in C→T (or G→A) substitutions. Conversely, ABE consists of an adenine deaminase fused to SpnCas9 for A→G (or T→C) editing. Several nucleotide substitutions were achieved using these plasmid-borne base-editing systems and a novel protospacer adjacent motif (PAM)-relaxed SpnCas9 (SpRY) variant. Base-editing was validated in Pseudomonas putida and other Gram-negative bacteria by inserting premature STOP codons into target genes, thereby inactivating both fluorescent proteins and metabolic (antibiotic-resistance) functions. The functional knockouts obtained by engineering STOP codons via CBE were reverted to the wild-type genotype using ABE. Additionally, a series of induction-responsive vectors was developed to facilitate the curing of the base-editing platform in a single cultivation step, simplifying complex strain engineering programs without relying on homologous recombination and yielding plasmid-free, modified bacterial cells.


Assuntos
Edição de Genes , Bactérias Gram-Negativas , Software , Adenina , Citidina/genética , Edição de Genes/métodos , Bactérias Gram-Negativas/genética , Nucleotídeos
17.
ACS Synth Biol ; 13(2): 485-497, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38235654

RESUMO

The plasmids from the Université d'Ottawa (pUdOs) are 28 small plasmids each comprising one of four origins of replication and one of seven selection markers, which together afford flexible use in Escherichia coli and several related gram-negative bacteria. The promoterless multicloning site is insulated from upstream spurious promoters by strong transcription terminators and contains type IIP or IIS restriction sites for conventional or Golden Gate cloning. pUdOs can be converted into efficient expression vectors through the insertion of a promoter at the user's discretion. For example, we demonstrate the utility of pUdOs as the backbone for an improved version of a Type III Secretion System reporter in Shigella. In addition, we derive a series of pUdO-based mammalian expression vectors, affording distinct levels of expression and transfection efficiency comparable to commonly used mammalian expression plasmids. Thus, pUdOs could advantageously replace traditional plasmids in a wide variety of cell types and applications.


Assuntos
Vetores Genéticos , Bactérias Gram-Negativas , Vetores Genéticos/genética , Plasmídeos/genética , Regiões Promotoras Genéticas/genética , Sequência de Bases , Bactérias Gram-Negativas/genética , Clonagem Molecular
18.
Diagn Microbiol Infect Dis ; 108(3): 116155, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38219381

RESUMO

AIM: To analyze the diagnostic utility of commercially available platforms and Whole-genome sequencing (WGS) for accurate determination of colistin susceptibility test results. MATERIAL & METHODS: An exploratory diagnostic accuracy study was conducted in which sixty carbapenem-resistant Gram-negative bacteria were subjected to identification and AST using MALDI-TOF MS & MicroScan walkaway 96 Plus. Additional AST was performed using the BD Phoenix system and Mikrolatest colistin kit. The test isolates were subjected to Vitek-2 and WGS at CRL, Bengaluru. RESULTS: There was no statistically significant agreement between the colistin susceptibility results obtained by WGS, with those of commercial phenotypic platforms. The MicroScan 96 Plus had the highest sensitivity (31 %) & NPV (77 %), and the BD Phoenix system had the highest specificity (97 %) and PPV (50 %), respectively, for determining colistin resistance. CONCLUSION: The utility of WGS as a tool in AMR surveillance and validation of phenotypic AST methods should be explored further.


Assuntos
Antibacterianos , Colistina , Humanos , Colistina/farmacologia , Antibacterianos/farmacologia , Carbapenêmicos/farmacologia , Bactérias Gram-Negativas/genética , Testes de Sensibilidade Microbiana
19.
Methods Mol Biol ; 2741: 11-24, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38217646

RESUMO

Outer membrane vesicles (OMVs), produced by Gram negative-bacteria and sRNAs, are key players in cell-to-cell communication and interactions of bacteria with the environment. OMVs act as information carriers and encapsulate various molecules such as proteins, lipids, metabolites, and RNAs. OMVs and sRNAs play a broad range of functions from pathogenesis to stress resistance, to biofilm formation and both mediate interkingdom signaling. Various studies indicate that there is a mechanism of intercellular communication mediated by OMV-derived bacterial RNAs that is conserved among certain bacterial species. Here we describe methods for the extraction and purification of vesicles produced by Gram-negative bacteria, such as Pseudomonas brassicacearum and Escherichia coli, and address methods for the extraction of OMVs-derived sRNA and techniques for the analysis of sRNAs.


Assuntos
Vesículas Extracelulares , Bactérias Gram-Negativas , Bactérias Gram-Negativas/genética , Escherichia coli/genética , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Vesículas Extracelulares/metabolismo
20.
J Appl Microbiol ; 135(1)2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38059867

RESUMO

Aquaculture has been recognized as a hotspot for the emergence and spread of antimicrobial resistance genes conferring resistance to clinically important antibiotics. This review gives insights into studies investigating the prevalence of colistin and carbapenem resistance (CCR) among Gram-negative bacilli in aquaculture. Overall, a high incidence of CCR has been reported in aquatic farms in several countries, with CCR being more prevalent among opportunistic human pathogens such as Acinetobacter nosocomialis, Shewanella algae, Photobacterium damselae, Vibrio spp., Aeromonas spp., as well as members of Enterobacteriaceae family. A high proportion of isolates in these studies exhibited wide-spectrum profiles of antimicrobial resistance, highlighting their multidrug-resistance properties (MDR). Several mobile colistin resistance genes (including, mcr-1, mcr-1.1, mcr-2, mcr-2.1, mcr-3, mcr-3.1, mcr-4.1, mcr-4.3, mcr-5.1, mcr-6.1, mcr-7.1, mcr-8.1, and mcr-10.1) and carbapenemase encoding genes (including, blaOXA-48, blaOXA-55, blaNDM, blaKPC, blaIMI, blaAIM, blaVIM, and blaIMP) have been detected in aquatic farms in different countries. The majority of these were carried on MDR Incompatibility (Inc) plasmids including IncA/C, and IncX4, which have been associated with a wide host range of different sources. Thus, there is a risk for the possible spread of resistance genes between fish, their environments, and humans. These findings highlight the need to monitor and regulate the usage of antimicrobials in aquaculture. A multisectoral and transdisciplinary (One Health) approach is urgently needed to reduce the spread of resistant bacteria and/or resistance genes originating in aquaculture and avoid their global reach.


Assuntos
Carbapenêmicos , Colistina , Animais , Humanos , Colistina/farmacologia , Carbapenêmicos/farmacologia , Prevalência , Saúde Pública , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias Gram-Negativas/genética , Plasmídeos , Aquicultura , Testes de Sensibilidade Microbiana , Farmacorresistência Bacteriana/genética
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