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Environmental Pollution (Barking, Essex... Aug 2022To date, carbapenem-resistant Enterobacteriaceae have been found predominantly in clinical settings worldwide. Raoultella belongs to the Enterobacteriaceae family which...
To date, carbapenem-resistant Enterobacteriaceae have been found predominantly in clinical settings worldwide. Raoultella belongs to the Enterobacteriaceae family which can cause hospital-acquired infections, and carbapenem-resistant Raoultella spp. (CRR) is sporadically reported in the environment. We investigated the distribution and underlying resistance mechanisms of CRR in a wastewater treatment plant (WWTP) from eastern China between January 2018 and February 2019. A total of 17 CRR were isolated from 324 environmental samples, including Raoultella ornithinolytica (n = 15) and Raoultella planticola (n = 2). The detection of CRR was more frequent in the water inlet compared to anaerobic tank, aerobic tank, sludge thickener, activated sludge, mud cake storage area, and water outlet, and CRR was detected in mud cake stacking area. All CRR were resistant to imipenem, meropenem, ampicillin, piperacillin-tazobactam, cefotaxime, ceftazidime, trimethoprim-sulfamethoxazole and fosfomycin. Four different carbapenemase genes were identified, including bla (n = 13), bla (n = 8), bla (n = 1), bla (n = 1). Interestingly, isolated R. ornithinolytica from the WWTP were closely related to those reported from human samples in China. Plasmid analysis indicated that IncFII(Yp), IncP6, and IncU mediated bla spread, IncX3 and IncN2 mediated bla spread in the environment. The core structure of the Tn3-ISKpn27-bla-ISKpn6, ISAba125-bla-ble-trpF-dsbD were identified. The study provides evidence that Raoultella spp. may spread alarming carbapenem resistance in the environment and, therefore, the continuous surveillance for carbapenem resistance in the WWTP should be conducted, especially sludge.
Topics: Humans; Anti-Bacterial Agents; Bacterial Proteins; beta-Lactamases; Carbapenems; Enterobacteriaceae; Microbial Sensitivity Tests; Plasmids; Sewage; Water
PubMed: 35537555
DOI: 10.1016/j.envpol.2022.119437 -
Infectious Diseases (London, England) Jul 2020There have been few clinical studies of infections but is potentially virulent and multidrug resistant. The aims of the study were to compare the clinical... (Comparative Study)
Comparative Study
There have been few clinical studies of infections but is potentially virulent and multidrug resistant. The aims of the study were to compare the clinical characteristics and outcomes of patients with and bloodstream infections (BSIs). We retrospectively reviewed the records of patients with and BSIs admitted to a tertiary hospital between 2008 and 2017. A total of 37 cases of BSIs were identified and matched to 160 cases of BSIs by age and sex using propensity score matching. Patients with BSIs were more likely to have underlying biliary tract disease (54.1% versus 24.4%; < .001) and have a community-acquired infection (62.2% versus 43.1%; = .04) than those with BSIs. Intra-abdominal infection was the most common primary focus of infection. Biliary tract infection (64.9% versus 38.8%; = .004) and pancreatitis (13.5% versus 3.8%; = .03) were more common in patients with BSIs. isolates exhibited significantly higher susceptibility to aztreonam, cefepime, and cefotaxime. The 14-day and 30-day mortality rates were lower among the patients with BSIs but did not differ significantly between groups (11% versus 22%; = .16 and 11% versus 26%; = .08 for and BSIs, respectively). spp. BSI more likely to occur in patients with underlying biliary tract disease and in community settings compared with BSIs. Biliary tract infection was the most common primary focus of BSIs.
Topics: Anti-Bacterial Agents; Bacteremia; Humans; Klebsiella Infections; Klebsiella pneumoniae; Retrospective Studies; Sepsis
PubMed: 32362190
DOI: 10.1080/23744235.2020.1758764 -
Frontiers in Microbiology 2023Rapid industrialization and urbanization have led to widespread metal contamination in aquatic ecosystems. This study explores the metal tolerance and biosorption...
Rapid industrialization and urbanization have led to widespread metal contamination in aquatic ecosystems. This study explores the metal tolerance and biosorption characteristics of four bacterial strains ( sp. L2, sp. L30, sp. R3, and sp. R19) isolated from Saint Clair River sediments. These strains effectively removed various metal cations (As, Pb, Cu, Mn, Zn, Cd, Cr, and Ni) in single and multi-metal solutions. Minimum inhibitory concentration (MIC) assays revealed strain-specific variations in metal tolerance, with L2 and L30 exhibiting higher tolerance. Surprisingly, R3 and R19, despite lower tolerance, demonstrated superior metal removal efficiency, challenging the notion that tolerance dictates removal efficacy. In single-metal solutions, R3 and R19 excelled at extracting various metal ions, while competitive binding in multi-metal solutions hindered removal. However, R3 and R19 retained higher removal efficiencies, possibly due to enhanced flocculation activities facilitating metal-ion contact. Comprehensive Fourier-transform infrared (FTIR) analysis highlighted the strains' metal-binding capabilities, with novel peaks emerging after metal exposure, indicative of extracellular polymeric substance (EPS) production. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed metal accumulation on bacterial surfaces and within cytoplasmic regions and revealed morphological changes and metal adsorption patterns, emphasizing the strains' ability to adapt to metal stress. Scanning transmission microscopy (STEM) and EDX analysis uncovered metal accumulation within bacterial cells, underscoring the complexity of microbial-metal interactions. This study also confirms that the simultaneous presence of an aqueous solution may cause a mutual inhibition in the adsorption of each metal to the EPS resulting in reduced metal uptake, which emphasizes the need to select specific bacterial strains for a given metal-containing effluent. The differences in metal distribution patterns between sp. R19 and sp. L30 suggest species-specific metal accumulation strategies driven by environmental conditions and metal availability. The heavy metal-removing capabilities and the ability to grow over a wide range of metal concentrations of the strains used in this study may offer an advantage to employ these organisms for metal remediation in bioreactors or .
PubMed: 37942073
DOI: 10.3389/fmicb.2023.1278886 -
Journal of Medical Microbiology Feb 2020spp. representatives are Gram-negative rod-shaped bacteria of the family. These bacteria are commonly found in the natural environment.. The aim of the study was to...
spp. representatives are Gram-negative rod-shaped bacteria of the family. These bacteria are commonly found in the natural environment.. The aim of the study was to indicate the reliable method for spp. strains identification, evaluate the susceptibility of spp. strains to selected antimicrobials and to detect their resistance mechanisms to beta-lactams. Susceptibility of the strains to chosen antimicrobials was determined using the automatic method. The presence of particular antimicrobial resistant mechanism and genes encoding ESBLs and MBLs was determined respectively with double-disc synergy test and commercially available kit - eazyplex SuperBug CRE test (Amplex Diagnostics) and standard PCR. For the selected strains, DNA sequencing was performed. Amongst 105 of the examined spp. strains, majority were sensitive to: imipenem (99.0 %), meropenem (98.1 %), gentamicin (93.3 %) and ciprofloxacin (92.4 %). Of the tested Raoultella strains, thirteen (12.4 %) produced ESBLs and one strain simultaneously ESBLs and MBLs. The DNA sequencing results were as follows: for all the reference strains the correct species identification was achieved, for the analysed strains two were identified as and one as . Although spp. strains remain sensitive to antibiotics, there is a constant need to monitor the sensitivity of these bacteria to selected antimicrobials. Isolation of a multi-drug resistant strain indicates that even the less frequently isolated species of family should be precisely identified because they might be of clinical importance and the particular strain can also produce enzymes that pose the greatest threat today.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Enterobacteriaceae; Enterobacteriaceae Infections; Humans; Imipenem; Meropenem; Microbial Sensitivity Tests; beta-Lactamases; beta-Lactams
PubMed: 31971501
DOI: 10.1099/jmm.0.001150 -
Indian Journal of Medical Microbiology 2018Raoultella is a Gram-negative bacteria, which commonly occur in the natural environment such as water, soil and on plants. In recent years, Raoultella spp. gained more...
BACKGROUND
Raoultella is a Gram-negative bacteria, which commonly occur in the natural environment such as water, soil and on plants. In recent years, Raoultella spp. gained more interest. There is also an increasing number of publications describing mainly clinical cases involving these bacteria. Identification of Raoultella spp. is difficult due to a phylogenetic relationship with Klebsiella spp.
PURPOSE
Available biochemical tests do not always allow for their identification to species. Thus, the aim of this study was to evaluate selected methods of identification of Raoultella spp. and their differentiation from genus Klebsiella.
MATERIALS AND METHODS
In this evaluation three methods were used such as manual test ID32E (bioMérieux), automatic test VITEK2 Compact (bioMérieux) and matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) method (Bruker).
RESULTS
Good identification of the species was obtained for 81.4% of the strains in the ID32E test, 93.3% in VITEK2 Compact test, and 97.4% in MALDI-TOF MS method, respectively.
CONCLUSION
It was established that MALDI-TOF MS method is reliable in identifying genus Raoultella.
Topics: Bacterial Typing Techniques; Enterobacteriaceae; Phylogeny; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 30084410
DOI: 10.4103/ijmm.IJMM_17_99 -
Journal of Hazardous Materials Sep 2023The simultaneous bioremediation and bioconversion of papermaking wastewater by psychrotrophic microorganisms holds great promise for developing sustainable environments...
The simultaneous bioremediation and bioconversion of papermaking wastewater by psychrotrophic microorganisms holds great promise for developing sustainable environments and economies in cold regions. Here, the psychrotrophic bacterium Raoultella terrigena HC6 presented high endoglucanase (26.3 U/mL), xylosidase (732 U/mL), and laccase (8.07 U/mL) activities for lignocellulose deconstruction at 15 °C. mRNA monitoring and phenotypic variation analyses confirmed that cold-inducible cold shock protein A (CspA) facilitated the expression of the cel208, xynB68, and lac432 genes to increase the enzyme activities in strain HC6. Furthermore, the cspA gene-overexpressing mutant (strain HC6-cspA) was deployed in actual papermaking wastewater and achieved 44.3%, 34.1%, 18.4%, 80.2% and 100% removal rates for cellulose, hemicellulose, lignin, COD, and NO-N at 15 °C. Simultaneously, 2,3-butanediol (2,3-BD) was produced from the effluent with a titer of 2.98 g/L and productivity of 0.154 g/L/h. This study reveals an association between the cold regulon and lignocellulolytic enzymes and provides a promising candidate for simultaneous papermaking wastewater treatment and 2,3-BD production.
Topics: Wastewater; Paper; Water Pollutants, Chemical; Biodegradation, Environmental
PubMed: 37418966
DOI: 10.1016/j.jhazmat.2023.131994 -
Antibiotics (Basel, Switzerland) Jun 2022The emergence and spread of antimicrobial resistance (AMR) has become a persistent problem globally. In this study, an ozone treatment facility was established for an...
The emergence and spread of antimicrobial resistance (AMR) has become a persistent problem globally. In this study, an ozone treatment facility was established for an advanced hospital wastewater treatment in a core hospital facility in an urban area in Japan to evaluate the inactivation of antimicrobial-resistant bacteria and antimicrobials. Metagenomic DNA-seq analysis and the isolation of potential extended-spectrum -lactamase (ESBL)-producing bacteria suggested that ozone exposure for at least 20 min is required for the adequate inactivation of DNA and ESBL-producing bacteria. and species were markedly susceptible to 20-min ozone exposure, whereas and were isolated even after an 80-min exposure. These ozone-resistant bacteria might play a pivotal role as AMR reservoirs in the environment. Nine antimicrobials (ampicillin, cefdinir, cefpodoxime, ciprofloxacin, levofloxacin, clarithromycin, chlortetracycline, minocycline, and vancomycin) were detected at 373 ng/L to 27 μg/L in the hospital wastewater, and these were removed (96-100% removal) after a 40-min treatment. These results facilitate a comprehensive understanding of the AMR risk posed by hospital wastewater and provides insights for devising strategies to eliminate or mitigate the burden of antimicrobial-resistant bacteria and the flow of antimicrobials into the environment. To the best of our knowledge, this is the first report on the implementation of a batch-type, plant-scale ozone treatment system in a hospital facility to execute and evaluate the inactivation of drug-resistant bacteria and antimicrobials.
PubMed: 35884116
DOI: 10.3390/antibiotics11070862 -
Microbiological Research Jan 2023of the current research was to use plant growth promoting rhizobacteria for sequestration and biotransformation of the toxic form of Cr and As into non-toxic form....
of the current research was to use plant growth promoting rhizobacteria for sequestration and biotransformation of the toxic form of Cr and As into non-toxic form. Remediating these contaminants using microbes is a common technique and rhizo-microbiota not only relieves metal stress but also acts as biofertilizers. Role of plant growth-promoting rhizobacterial (PGPR) strains Acinetobacter beijerinckii (C5) and Raoultella planticola (C9) in counteracting chromium and arsenic stress in soybean seedlings was assessed. The isolated rhizobacteria were able to tolerate excessive quantities (up to 1200 ppm) of chromate and arsenate in liquid media. Beside their growth in heavy metal containing media, the strains were able to bio-transform chromate and arsenate to their least toxic form. They released significant quantities of stress related metabolites including phenols, flavonoids, proline, sugars and protein even in the presence of 1200 ppm of the heavy metals. They also released several plant hormones together with indole-3-acetic acid (IAA), salicylic acid (SA) and gibberellins. Another important feature of the isolates was their ability to solubilize phosphate and release siderophores and exposure to different levels of the selected heavy metals enhanced phosphate solubilization potential of both the isolates by up to 2-fold. Release of siderophore in A. beijerinckii C5 was enhanced by increasing heavy metals concentration in the media but in case of R. planticola C9 a decline was noted. When inoculated on soybean seedlings, the isolates modulated several metabolites of the hos plant enabling them to combat heavy metal toxicity at different levels. The PGPR strains boosted host's antioxidants production which minimized the oxidative damage by scavenging excessive ROS produced under stress. Control plants showed upregulation of stress response metabolites compared to PGPR application, whereas, IAA and SA were significantly higher in PGPR associated seedlings. In conclusion, PGPR alters the physiological and metabolic responses of soybean enabling it to cope better with chromate and arsenic toxicity and grow well under the stress.
Topics: Plant Growth Regulators; Glycine max; Arsenates; Chromates; Arsenic; Metals, Heavy; Seedlings; Siderophores; Phosphates
PubMed: 36270107
DOI: 10.1016/j.micres.2022.127237 -
Journal of Applied Microbiology Aug 2017To isolate and identify TNT-transforming cultures from explosive-contaminated soils with the ability to produce biosurfactants.
AIMS
To isolate and identify TNT-transforming cultures from explosive-contaminated soils with the ability to produce biosurfactants.
METHODS AND RESULTS
Bacteria (pure and mixed cultures) were selected based on their ability to transform TNT in minimum media with TNT as the sole nitrogen source and an additional carbon source. TNT-transforming bacteria were identified by 16S rRNA gene sequencing. TNT transformation rates were significantly lower when no additional carbon or nitrogen sources were added. Surfactant production was enabled by the presence of TNT. Fourteen cultures were able to transform the explosive (>50%); of these, five showed a high transformation capacity (>90%), and six produced surfactants.
CONCLUSIONS
All explosive-transforming cultures contained Proteobacteria of the genera Achromobacter, Stenotrophomonas, Pseudomonas, Sphingobium, Raoultella, Rhizobium and Methylopila. These cultures transformed TNT when an additional carbon source was added. Remarkably, Achromobacter spanius S17 and Pseudomonas veronii S94 have high TNT transformation rates and are surfactant producers.
SIGNIFICANCE AND IMPACT OF THE STUDY
TNT is a highly toxic, mutagenic and carcinogenic nitroaromatic explosive; therefore, bioremediation to eliminate or mitigate its presence in the environment is essential. TNT-transforming cultures that produce surfactants are a promising method for remediation. To the best of our knowledge, this is the first report that links surfactant production and TNT transformation by bacteria.
Topics: Bacteria; Biodegradation, Environmental; Biotransformation; Carbon; Nitrogen; Soil Microbiology; Soil Pollutants; Surface-Active Agents; Trinitrotoluene
PubMed: 28561275
DOI: 10.1111/jam.13504 -
Research in Microbiology 2022
Corrigendum to "Proposal for reunification of the genus Raoultella with the genus Klebsiella and reclassification of Raoultella electrica as Klebsiella electrica comb. nov." [Res microbiol 172 (2021) 103851].
PubMed: 35816932
DOI: 10.1016/j.resmic.2022.103924