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Biofilm Dec 2023Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and...
Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and recurring problem that blocks transport over membranes and decreases the water recovery. Microorganisms adhering to membranes may form biofilm and produce an extracellular matrix, which protects against external stress and ensures continuous attachment. Thus, various agents are tested for their ability to degrade and disperse biofilms. Here, we identified industrially relevant bacterial model communities that form biofilms on RO membranes used for treating process water before reuse. There was a marked difference in the biofilm forming capabilities of bacteria isolated from contaminated RO membranes. One species, , was particularly capable of forming biofilm and was included in most communities. The potential of different enzymes (Trypsin-EDTA, Proteinase K, α-Amylase, β-Mannosidase and Alginate lyase) as biofouling dispersing agents was evaluated at different concentrations (0.05 U/ml and 1.28 U/ml). Among the tested enzymes, β-Mannosidase was the only enzyme able to reduce biofilm formation significantly within 4 h of exposure at 25 °C (0.284 log reduction), and only at the high concentration. Longer exposure duration, however, resulted in significant biofilm reduction by all enzymes tested (0.459-0.717 log reduction) at both low and high concentrations. Using confocal laser scanning microscopy, we quantified the biovolume on RO membranes after treatment with two different enzyme mixtures. The application of proteinase K and β-Mannosidase significantly reduced the amount of attached biomass (43% reduction), and the combination of all five enzymes showed even stronger reducing effect (71% reduction). Overall, this study demonstrates a potential treatment strategy, using matrix-degrading enzymes for biofouled RO membranes in food processing water treatment streams. Future studies on optimization of buffer systems, temperature and other factors could facilitate cleaning operations based on enzymatic treatment extending the lifespan of membranes with a continuous flux.
PubMed: 37131492
DOI: 10.1016/j.bioflm.2023.100119 -
The Science of the Total Environment Aug 2023Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater...
Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater (WW). Current WW technologies do not present satisfactory efficiency or sustainability in removing these contaminants. However, bioremediation with microalgae-based systems is proving to be a relevant technology for WW polishing, and the use of microalgae-bacteria consortia can improve the efficiency of WW treatment. This work aimed to study dual cultures of selected bacteria (Raoultella ornithinolytica, Acidovorax facilis, Acinetobacter calcoaceticus, Leucobacter sp. or Rhodococcus fascians) and the microalga Chlorella vulgaris in microbial growth and WW bioremediation - removal of methylparaben (MetP) and nutrients. The association with the bacteria was antagonistic for C. vulgaris biomass productivity as a result of the decreased growth kinetics in comparison to the axenic microalga. The presence of MetP did not disturb the growth of C. vulgaris under axenic or co-cultured conditions, except when associated with R. fascians, where growth enhancement was observed. The removal of MetP by the microalga was modest (circa 30 %, with a removal rate of 0.0343 mg/L.d), but increased remarkably when the consortia were used (> 50 %, with an average removal rate > 0.0779 mg/L.d), through biodegradation and photodegradation. For nutrient removal, the consortia were found to be less effective than the axenic microalga, except for nitrogen (N) removal by C. vulgaris w/ R. fascians. The overall results propose that C. vulgaris co-cultivation with bacteria can increase MetP removal, while negatively affecting the microalga growth and the consequent reduction of sludge production, highlighting the potential of microalgae-bacteria consortia for the effective polishing of WW contaminated with parabens.
Topics: Chlorella vulgaris; Wastewater; Coculture Techniques; Parabens; Bacteria; Microalgae
PubMed: 37121314
DOI: 10.1016/j.scitotenv.2023.163746 -
Case Reports in Infectious Diseases 2023An 80-year-old woman underwent pancreatoduodenectomy. Post-operation, she experienced a fever, and a culture of blood revealed metallo-beta-lactamase-producing For...
Successful Treatment of a Case of Metallo-Beta-Lactamase-Producing Bacteremia by Antimicrobial Stewardship Team Intervention and Therapeutic Drug Monitoring-Based Amikacin Treatment.
An 80-year-old woman underwent pancreatoduodenectomy. Post-operation, she experienced a fever, and a culture of blood revealed metallo-beta-lactamase-producing For treatments with aminoglycoside antimicrobial agents, a therapeutic drug monitoring-based dosing design can lower the risk of adverse events and enable appropriate treatment. . When aminoglycoside antimicrobial agents are administered for MBL-producing bacteremia, prescription suggestions based on TDM by antimicrobial stewardship team can reduce the occurrence of adverse events and enable appropriate treatment.
PubMed: 37065978
DOI: 10.1155/2023/5574769 -
Diagnostic Microbiology and Infectious... Jun 2023A total of 35,360 Enterobacterales isolates were consecutively collected from 75 US medical centers in 2018-2022. Among these isolates, 2612 (7.4%) were categorized as...
Ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-relebactam activities against multidrug-resistant Enterobacterales from United States Medical Centers (2018-2022).
A total of 35,360 Enterobacterales isolates were consecutively collected from 75 US medical centers in 2018-2022. Among these isolates, 2612 (7.4%) were categorized as multidrug-resistant (MDR). Isolates were susceptibility tested by reference broth microdilution methods. Carbapenem-resistant Enterobacterales (CRE) were screened for carbapenemase (CPE) genes by whole genome sequencing. The highest MDR rates was observed among Klebsiella pneumoniae (12.2%), followed by Raoultella spp. (10.9%) and Providencia stuartii (9.8%). Ceftazidime-avibactam and meropenem-vaborbactam were very active and showed identical susceptibility rates against MDR isolates (97.9%). Imipenem-relebactam (93.5% susceptible [S]) exhibited slightly lower susceptibility rates due to its limited activity against Morganellaceae family. The most active β-lactamase inhibitor combination (BLI) against CRE isolates (n = 310) was ceftazidime-avibactam (84.2%S), followed by meropenem-vaborbactam (81.9%S) and imipenem-relebactam (74.8%S). All 3 BLIs were very active against KPC producers and none were active against MBL producers. Ceftazidime-avibactam exhibited greater activity against OXA-48-type producers than meropenem-vaborbactam and imipenem-vaborbactam.
Topics: United States; Humans; Meropenem; Anti-Bacterial Agents; Ceftazidime; Azabicyclo Compounds; Drug Combinations; Imipenem; beta-Lactamases; Carbapenems; Microbial Sensitivity Tests
PubMed: 37060707
DOI: 10.1016/j.diagmicrobio.2023.115945 -
Microbiology Resource Announcements May 2023Raoultella ornithinolytica is an emerging pathogen that causes human infections. We report the isolation and genome sequencing of from an oral swab of a Persian pet cat...
Raoultella ornithinolytica is an emerging pathogen that causes human infections. We report the isolation and genome sequencing of from an oral swab of a Persian pet cat in Dhaka, Bangladesh. The genome length was 5,375,160 bp, with 55.9% G+C content. It carries putative genes associated with resistance to antibiotics and metals.
PubMed: 37036345
DOI: 10.1128/mra.00863-22 -
Microbiology Resource Announcements May 2023We present the full genome sequence of a colistin-resistant Raoultella electrica strain (MIC, >4 μg/mL) that was isolated from the stool of a healthy person living in...
We present the full genome sequence of a colistin-resistant Raoultella electrica strain (MIC, >4 μg/mL) that was isolated from the stool of a healthy person living in India. The sequence consists of a chromosome and three plasmids (5,455,992-bp and 98,913-bp, 4,232-bp, and 3,961-bp, respectively). No previously described colistin resistance mechanisms were detected.
PubMed: 37014211
DOI: 10.1128/mra.00047-23 -
International Journal of Food... Jun 2023Interaction between Listeria monocytogenes and resident background microbiota may occur in food processing environments and may influence the survival of this pathogen...
Interaction between Listeria monocytogenes and resident background microbiota may occur in food processing environments and may influence the survival of this pathogen in a factory environment. Therefore the aim of this study was to characterize the growth performance of microbiota isolated from the processing environments of frozen sliced mushrooms, and to investigate the competitive performance of L. monocytogenes when co-cultured with accompanying environmental microbiota. Acinetobacter, Enterobacteriaceae, Lactococcus and Pseudomonas were the most prominent background microbiota isolated from the processing environment of frozen sliced mushrooms. All individual microbiota strains were able to grow and form biofilm in filter-sterilized mushroom medium, with the mannitol-consumers Raoultella and Ewingella as top performers, reaching up to 9.6 and 9.8 log CFU/mL after 48 h incubation at room temperature. When L. monocytogenes mushroom isolates were co-cultured with the microbiota strains, L. monocytogenes counts ranged from 7.6 to 8.9 log CFU/mL after 24 h of incubation, while counts of the microbiota strains ranged from 5.5 to 9.0 log CFU/mL. Prolonged incubation up to 48 h resulted in further increase of L. monocytogenes counts when co-cultured with non-acidifying species Pseudomonas and Acinetobacter reaching 9.1 to 9.2 log CFU/mL, while a decrease of L. monocytogenes counts reaching 5.8 to 7.7 log CFU/mL was observed in co-culture with Enterobacteriaceae and acidifying Lactococcus representatives. In addition, L. monocytogenes grew also in spent mushroom media of the microbiota strains, except in acidified spent media of Lactococcus strains. These results highlight the competitive ability of L. monocytogenes during co-incubation with microbiota in fresh and in spent mushroom medium, indicative of its invasion and persistence capacity in food processing factory environments.
Topics: Listeria monocytogenes; Agaricales; Food Microbiology; Food Handling; Pseudomonas; Enterobacteriaceae; Lactococcus; Microbiota; Colony Count, Microbial
PubMed: 37001480
DOI: 10.1016/j.ijfoodmicro.2023.110183 -
PloS One 2023To study antimicrobial resistance and virulence genes of Klebsiella pneumoniae and Raoultella strains isolated from captive giant pandas. Non-duplicate fecal samples...
To study antimicrobial resistance and virulence genes of Klebsiella pneumoniae and Raoultella strains isolated from captive giant pandas. Non-duplicate fecal samples were collected from 128 giant pandas during 2017-2019. All isolated microbial strains were tested for antimicrobial drug susceptibility using BD verification panels. Four extended-spectrum β-lactamase resistance genes, nine virulence genes and six capsular serotype genes were detected using PCR. 42 K. pneumoniae and nine Raoultella strains were isolated from different giant pandas. Antibiotic resistance rates were 1.9%-23.5%, except for ampicillin, and 7.8% of the isolates were multidrug-resistant to 7-10 antibiotic classes. This is the first time that a multidrug-resistant R. ornithinolytica strain has been isolated from captive giant pandas. The blaTEM, blaCTX-M, blaSHV and blaDHA genes were detected in four MDR ESBL- K. pneumoniae strains. The rmpA, iutA, ybtS, iroN and iroB genes were positively detected in 11.7% of the isolates. Capsular serotype (K2, K5, K54 and K57) genes were all detected in four K. pneumoniae strains, and one was identified as hypervirulent. This study showed that MDR ESBL- K. pneumoniae, hypervirulent K. pneumoniae, MDR R. ornithinolytica and the colistin-resistant strain may pose risks to captive giant pandas and their keepers, and that the diversity of antibiotic resistance and virulence genes in Klebsiella and Raoultella should be monitored regularly.
Topics: Animals; Anti-Bacterial Agents; Virulence; Klebsiella pneumoniae; Ursidae; Drug Resistance, Bacterial; Prevalence; Klebsiella Infections; beta-Lactamases; Microbial Sensitivity Tests
PubMed: 36996135
DOI: 10.1371/journal.pone.0283738 -
Medicina (Kaunas, Lithuania) Mar 2023is a Gram-negative bacterium rarely involved in urinary tract infections. The patient was an 80-year-old woman with several associated diseases who presented to the...
is a Gram-negative bacterium rarely involved in urinary tract infections. The patient was an 80-year-old woman with several associated diseases who presented to the hospital with fever and dysuria. was identified to be the causative agent of the urinary tract infection. Antibacterial treatment led to a full recovery within 7 days. This report highlights the presence of a rare pathogen as a causative agent in the case of a urinary tract infection and also the importance of using multiple methods in order to identify bacteria and to establish the diagnosis.
Topics: Female; Humans; Aged, 80 and over; Enterobacteriaceae Infections; Romania; Enterobacteriaceae; Anti-Bacterial Agents; Urinary Tract Infections
PubMed: 36984507
DOI: 10.3390/medicina59030506 -
GigaByte (Hong Kong, China) 2023Rapid screening of hospital admissions to detect asymptomatic carriers of resistant bacteria can prevent pathogen outbreaks. However, the resulting isolates rarely have...
Rapid screening of hospital admissions to detect asymptomatic carriers of resistant bacteria can prevent pathogen outbreaks. However, the resulting isolates rarely have their genome sequenced due to cost constraints and long turn-around times to get and process the data, limiting their usefulness to the practitioner. Here we used real-time, on-device target enrichment ("adaptive") sequencing as a highly multiplexed assay covering 1,147 antimicrobial resistance genes. We compared its utility against standard and metagenomic sequencing, focusing on an isolate of harbouring three carbapenemases (, , ). Based on this experimental data, we then modelled the influence of several variables on the enrichment results and predicted the large effect of nucleotide identity (higher is better) and read length (shorter is better). Lastly, we showed how all relevant resistance genes are detected using adaptive sequencing on a miniature ("Flongle") flow cell, motivating its use in a clinical setting to monitor similar cases and their surroundings.
PubMed: 36949817
DOI: 10.46471/gigabyte.75