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UCL Open. Environment 2023The aim of this study is to obtain knowledge about which cultivable bacterial species are present in indoor air in homes, and whether the concentration and diversity of...
The aim of this study is to obtain knowledge about which cultivable bacterial species are present in indoor air in homes, and whether the concentration and diversity of airborne bacteria are associated with different factors. Measurements have been performed for one whole year inside different rooms in five homes and once in 52 homes. Within homes, a room-to-room variation for concentrations of airborne bacteria was found, but an overlap in bacterial species was found across rooms. Eleven species were found very commonly and included: , , , , , and . The concentrations of Gram-negative bacteria in general and the species were significantly associated with the season with the highest concentrations in spring. The concentrations of , and were associated positively with relative humidity (RH), and concentrations of were associated negatively with temperature and air change rate (ACR). concentrations were associated negatively with ACR. Overall, this study identified species which are commonly present in indoor air in homes, and that the concentrations of some species were associated with the factors: season, ACR and RH.
PubMed: 37229345
DOI: 10.14324/111.444/ucloe.000056 -
Sensors (Basel, Switzerland) Nov 2022Microbial mediator biosensors for surface water toxicity determination make it possible to carry out an early assessment of the environmental object’s quality without...
Microbial mediator biosensors for surface water toxicity determination make it possible to carry out an early assessment of the environmental object’s quality without time-consuming standard procedures based on standard test-organisms, and provide broad opportunities for receptor element modifying depending on the required operational parameters analyzer. Four microorganisms with broad substrate specificity and nine electron acceptors were used to form a receptor system for toxicity assessment. Ferrocene was the most effective mediator according to its high rate constant of interaction with the microorganisms (0.33 ± 0.01 dm3/(g × s) for yeast Saccharomyces cerevisiae). Biosensors were tested on samples containing four heavy metal ions (Cu2+, Zn2+, Pb2+, Cd2+), two phenols (phenol and p-nitrophenol), and three natural water samples. The «ferrocene- Escherichia coli» and «ferrocene-Paracoccus yeei, E. coli association» systems showed good operational stability with a relative standard deviation of 6.9 and 7.3% (14 measurements) and a reproducibility of 7 and 5.2% using copper (II) ions as a reference toxicant. Biosensor analysis with these systems was shown to highly correlate with the results of the standard method using Chlorella algae as a test object. Developed biosensors allow for a valuation of the polluted natural water’s impact on the ecosystem via an assessment of the influence on bacteria and yeast in the receptor system. The systems could be used in toxicological monitoring of natural waters.
Topics: Metallocenes; Water; Escherichia coli; Saccharomyces cerevisiae; Reproducibility of Results; Chlorella; Ecosystem; Biosensing Techniques; Metals, Heavy; Water Pollutants, Chemical
PubMed: 36366221
DOI: 10.3390/s22218522 -
Membranes Oct 2022Biomembranes based on an organosilica sol-gel matrix were used to immobilize bacteria VKM B-3302 as part of a biochemical oxygen demand (BOD) biosensor....
Biomembranes based on an organosilica sol-gel matrix were used to immobilize bacteria VKM B-3302 as part of a biochemical oxygen demand (BOD) biosensor. Diethoxydimethylsilane (DEDMS) and tetraethoxysilane (TEOS) were used as precursors to create the matrix in a 1:1 volume ratio. The use of scanning electron microscopy (SEM) and the low-temperature nitrogen adsorption method (BET) showed that the sol-gel matrix forms a capsule around microorganisms that does not prevent the exchange of substrates and waste products of bacteria to the cells. The use of DEDMS as part of the matrix made it possible to increase the sensitivity coefficient of the biosensor for determining BOD by two orders of magnitude compared to a biosensor based on methyltriethoxysilane (MTES). Additionally, the long-term stability of the bioreceptor increased to 68 days. The use of such a matrix neutralized the effect of heavy metal ions on the microorganisms' catalytic activity in the biosensor. The developed biosensor was used to analyze water samples from water sources in the Tula region (Russia).
PubMed: 36295743
DOI: 10.3390/membranes12100983 -
Biofilm Dec 2022In patients with acute respiratory failure, mechanical ventilation through an endotracheal tube (ET) may be required to correct hypoxemia and hypercarbia. However,...
In patients with acute respiratory failure, mechanical ventilation through an endotracheal tube (ET) may be required to correct hypoxemia and hypercarbia. However, biofilm formation on these ETs is a risk factor for infections in intubated patients, as the ET can act as a reservoir of microorganisms that can cause infections in the lungs. As severely ill COVID-19 patients often need to be intubated, a better knowledge of the composition of ET biofilms in this population is important. In Spring 2020, during the first wave of the COVID-19 pandemic in Europe, 31 ETs were obtained from COVID-19 patients at Ghent University Hospital (Ghent, Belgium). Biofilms were collected from the ET and the biofilm composition was determined using culture-dependent (MALDI-TOF mass spectrometry and biochemical tests) and culture-independent (16S and ITS1 rRNA amplicon sequencing) approaches. In addition, antimicrobial resistance was assessed for isolates collected via the culture-dependent approach using disc diffusion for 11 antimicrobials commonly used to treat lower respiratory tract infections. The most common microorganisms identified by the culture-dependent approach were those typically found during lung infections and included both presumed commensal and potentially pathogenic microorganisms like , , and . More unusual organisms, such as , were also identified, but each only in a few patients. The culture-independent approach revealed a wide variety of microbes present in the ET biofilms and showed large variation in biofilm composition between patients. Some biofilms contained a diverse set of bacteria of which many are generally considered as non-pathogenic commensals, whereas others were dominated by a single or a few pathogens. Antimicrobial resistance was widespread in the isolates, e.g. 68% and 53% of all isolates tested were resistant against meropenem and gentamicin, respectively. Different isolates from the same species recovered from the same ET biofilm often showed differences in antibiotic susceptibility. Our data suggest that ET biofilms are a potential risk factor for secondary infections in intubated COVID-19 patients, as is the case in mechanically-ventilated non-COVID-19 patients.
PubMed: 35720435
DOI: 10.1016/j.bioflm.2022.100079 -
Saudi Journal of Kidney Diseases and... 2021Peritoneal dialysis (PD) peritonitis poses a significant healthcare problem. Most cases are caused by Gram-positive organisms. Newer molecular diagnostic techniques have...
Peritoneal dialysis (PD) peritonitis poses a significant healthcare problem. Most cases are caused by Gram-positive organisms. Newer molecular diagnostic techniques have now enabled identification of previously unrecognized organisms, fully characterizing disease. We present the first case of Paracoccus yeei PD peritonitis reported in the United Kingdom (UK). A 70-year-old woman with chronic renal failure requiring PD presented with abdominal pain and cloudy dialysate. She was systemically well, with a normal white cell count and elevated C-reactive protein at 176. PD fluid was remarkable for 4495 polymorphonuclear leukocytes, 107 monocytes, and 10 red blood cells/cm. No organisms were seen on microscopy. She was diagnosed with PD peritonitis and treated empirically with intraperitoneal vancomycin and oral levofloxacin. After two days, small, nonhemolytic gray-white colonies grew on blood agar. Gram stain of culture showed Gram-negative cocco-bacilli with O-shaped morphology. Phenotypic identification using matrix-assisted laser desorption ionization-time of flight mass spectrometry (Biomerieux) identified P. yeei (identification probability 99.9%). The isolate was sent to the reference laboratory for confirmation and antimicrobial susceptibility testing (AST). At present, there are no European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints to guide AST. Proposed minimum inhibitory concentration (MIC) values were determined using broth dilution method interpreted using EUCAST nonspecies-specific PK-PD breakpoints (where available). The isolate was reported as sensitive to quinolones (ciprofloxacin MIC 0.25 mg/L), piperacillin-tazobactam (MIC 2 mg/L), and meropenem (MIC 0.008 mg/L). P. yeei is an aerobic environmental organism found in soil. It has been associated with PD peritonitis in immunosuppressed patients, although this is the first case in the UK. It is possible that true burden of disease is under-represented, and novel molecular techniques have now enabled identification of this previously unknown organism. In this case, her dog could be a potential source, and good hand hygiene may prevent further infections.
Topics: Animals; Anti-Bacterial Agents; Dogs; Female; Humans; Paracoccus; Peritoneal Dialysis; Peritonitis; Vancomycin
PubMed: 35229817
DOI: 10.4103/1319-2442.338291 -
Frontiers in Physiology 2021New types of fish feed based on processed animal proteins (PAPs), insect meal, yeast, and microbial biomasses have been used with success in gilthead sea bream. However,...
Cross-Talk Between Intestinal Microbiota and Host Gene Expression in Gilthead Sea Bream () Juveniles: Insights in Fish Feeds for Increased Circularity and Resource Utilization.
New types of fish feed based on processed animal proteins (PAPs), insect meal, yeast, and microbial biomasses have been used with success in gilthead sea bream. However, some drawback effects on feed conversion and inflammatory systemic markers were reported in different degrees with PAP- and non-PAP-based feed formulations. Here, we focused on the effects of control and two experimental diets on gut mucosal-adherent microbiota, and how it correlated with host transcriptomics at the local (intestine) and systemic (liver and head kidney) levels. The use of tissue-specific PCR-arrays of 93 genes in total rendered 13, 12, and 9 differentially expressed (DE) genes in the intestine, liver, and head kidney, respectively. Illumina sequencing of gut microbiota yielded a mean of 125,350 reads per sample, assigned to 1,281 operational taxonomic unit (OTUs). Bacterial richness and alpha diversity were lower in fish fed with the PAP diet, and discriminant analysis displayed 135 OTUs driving the separation between groups with 43 taxa correlating with 27 DE genes. The highest expression of intestinal and was achieved in PAP fish with intermediate values in non-PAP, being the pro-inflammatory action of associated with the presence of . The intestinal gene was down-regulated in non-PAP fish, with this gene being negatively correlated with anaerobic (Chloroflexi and ) and metal-reducing ( and ) bacteria. Other inflammatory markers (α) were up-regulated in PAP fish, positively correlating the intestinal gene with the inflammasome activator , whereas the systemic expression of and α was negatively correlated with the Bacilli class in PAP fish and positively correlated with in non-PAP fish. Overall changes in the expression pattern of , galectins (), and toll-like receptors () reinforced the anti-inflammatory profile of fish fed with the non-PAP diet, with these gene markers being associated with a wide range of OTUs. A gut microbiota-liver axis was also established, linking the microbial generation of short chain fatty acids with the fueling of - and -mediated lipogenesis. In summary, by correlating the microbiome with host gene expression, we offer new insights in the evaluation of fish diets promoting gut and metabolism homeostasis, and ultimately, the health of farmed fish.
PubMed: 34675821
DOI: 10.3389/fphys.2021.748265 -
Enzyme and Microbial Technology Jan 2022In this publication an alternative approach to investigations of bacterial growth is proposed. Contrary to the conventional physical methods it is based on enzyme...
In this publication an alternative approach to investigations of bacterial growth is proposed. Contrary to the conventional physical methods it is based on enzyme activity detection. The procedure for real-time and on-line monitoring of microbial ureolytic activity (applied as a model experimental biosystem) in the flow analysis format is presented. The developed fully-mechanized bioanalytical flow system is composed of solenoid micropumps and microvalves actuated by Arduino microcontroller. The photometric detection based on Nessler reaction is performed using dedicated flow-through optoelectronic detector made of paired light emitting diodes. The developed bioanalytical system allows discrete assaying of microbial urease in the wide range of activity up to 5.4 U mL with detection limit below 0.44 U mL, a high sensitivity in the linear range of response (up to 200 mV U mL and relatively high throughput (9 detection per hour). The proposed differential procedure of measurements (i.e. a difference between peaks register for sample with and without external addition of urea is treated as an analytical signal) allows elimination of interfering effects from substrate and products of biocatalysed reaction as well as other components of medium used for microbial growth. The developed bioanalytical system was successfully applied for the control of growth of urease-positive bacteria strains (Proteus vulgaris, Klebsiella pneumoniae and Paracoccus yeei) including examination of effects from various microbial cultivation conditions like temperature, composition of culture medium and amount of substrate required for induction of bacterial enzymatic activity. The developed bioanalytical flow system can be applied for metabolic activity-based estimation of parameters of lag and log phases of microbial growth as well as for detection of decline phase.
Topics: Bacteria; Culture Media; Klebsiella pneumoniae; Urea; Urease
PubMed: 34670184
DOI: 10.1016/j.enzmictec.2021.109899 -
Frontiers in Public Health 2021Disinfection is a key element in controlling infections. Fogging, also known as fumigation, is one of the most effective chemical disinfection methods. Peracetic acid...
Disinfection is a key element in controlling infections. Fogging, also known as fumigation, is one of the most effective chemical disinfection methods. Peracetic acid (PAA) is a powerful oxidant with bactericidal and fungicidal properties. The aim of this study is to determine the type of bacteria and fungi present in educational institutions and whether disinfection by PAA fumigation in these institutions is also effective and useful, as demonstrated previously in healthcare centers. This study was carried out in five kindergartens and five primary schools in Bialystok, Poland. Three rooms have been selected in each of these educational institutions, and the disinfection was carried out in 30 rooms in total. Fogging with PAA was performed in selected rooms. Before and after disinfection, samples were collected from four surfaces: walls, tables, doors, and chair backs. Most frequently detected microorganisms in schools and kindergartens were ssp. . In addition, ssp. were the most prevalent in kindergartens, whereas was the most prevalent in schools. Comparison of the bacterial flora of schools and kindergartens showed statistically significant differences in the prevalence of bacteria on different surfaces. A significant decrease in the number of colonies after disinfection was observed on all surfaces ( < 0.05). In addition, the calculated effectiveness of disinfection was 99.7% in kindergartens and 99.3% in schools. The results indicate that fogging of PAA is a highly effective method of surface disinfection in kindergartens and schools.
Topics: Acinetobacter; Actinobacteria; Micrococcaceae; Paracoccus; Peracetic Acid; Schools; Staphylococcus
PubMed: 34604154
DOI: 10.3389/fpubh.2021.697917 -
F1000Research 2021: Metagenomic sequencing has the potential to identify a wide range of pathogens in human tissue samples. Sarcoidosis is a complex disorder whose etiology remains...
: Metagenomic sequencing has the potential to identify a wide range of pathogens in human tissue samples. Sarcoidosis is a complex disorder whose etiology remains unknown and for which a variety of infectious causes have been hypothesized. We sought to conduct metagenomic sequencing on cases of ocular and periocular sarcoidosis, none of them with previously identified infectious causes. : Archival tissue specimens of 16 subjects with biopsies of ocular and periocular tissues that were positive for non-caseating granulomas were used as cases. Four archival tissue specimens that did not demonstrate non-caseating granulomas were also included as controls. Genomic DNA was extracted from tissue sections. DNA libraries were generated from the extracted genomic DNA and the libraries underwent next-generation sequencing. : We generated between 4.8 and 20.7 million reads for each of the 16 cases plus four control samples. For eight of the cases, we identified microbial pathogens that were present well above the background, with one potential pathogen identified for seven of the cases and two possible pathogens for one of the cases. Five of the eight cases were associated with bacteria ( and ), two cases with fungi ( ) and one case with a virus (Mupapillomavirus 1). Interestingly, four of the five bacterial species are also part of the human oral microbiome. : Using a metagenomic sequencing we identified possible infectious causes in half of the ocular and periocular sarcoidosis cases analyzed. Our findings support the proposition that sarcoidosis could be an etiologically heterogenous disease. Because these are previously banked samples, direct follow-up in the respective patients is impossible, but these results suggest that sequencing may be a valuable tool in better understanding the etiopathogenesis of sarcoidosis and in diagnosing and treating this disease.
Topics: Bacteria; High-Throughput Nucleotide Sequencing; Humans; Metagenome; Metagenomics; Microbiota; Sarcoidosis
PubMed: 36212901
DOI: 10.12688/f1000research.55090.1 -
3 Biotech Jul 2021We have studied immobilization of VKM B-3302 cells in an organosilica sol-gel matrix consisting of tetraethoxysilane, methyltriethoxysilane and polyvinyl alcohol as a...
We have studied immobilization of VKM B-3302 cells in an organosilica sol-gel matrix consisting of tetraethoxysilane, methyltriethoxysilane and polyvinyl alcohol as a structure-modifying agent. Optical microscopy showed that higher amounts of methyltriethoxysilane make the solid material structure softer. In addition, formation of structures, probably, with bacterial cells inside was spotted. We have analyzed the catalytic power of the immobilized bacteria and discovered that the material's catalytic potential is the highest at 50% of methyltriethoxysilane. Therefore, this seems to be the best ratio of precursors in a material for bacteria to become effectively encapsulated. Analysis of the material structure by low-temperature nitrogen absorption and scanning electron microscopy revealed that in the given conditions the material got crack-like mesopores and spherical particles of about 25 µm in diameter with immobilized bacterial cells on their surface. The study found that the fabricated organosilica material can effectively protect bacterial cells against UV radiation, pH change, high salinity and high heavy metal ion concentration.
PubMed: 34194914
DOI: 10.1007/s13205-021-02863-z