Bacterial Plate Research Articles

Effect of Pipe Materials and Interspecific Interactions on Biofilm Formation and Chlorine Resistance: Turn Enemies into Friends

Drinking water distribution systems (DWDSs) may be contaminated to various degrees when different microorganisms attach to the pipe walls. Understanding the characteristics of biofilms on pipe walls can help prevent and control microbial contamination in DWDSs. The biofilm formation, interspecific interactions, and chlorine resistance of 10 dual-species biofilms in polyethylene (PE) and cast iron (CI) pipes were investigated in this paper. The biofilm biomass (heterotrophic bacterial plate count and crystal violet) of dual species in CI pipes is significantly higher than that in PE pipes, but the biofilm activity in CI pipes is significantly lower than that in PE pipes. The interspecific interaction of Sphingomonas-containing group presented synergistic or neutral relationship in PE pipes, whereas the interspecific interaction of the Acidovorax-containing group showed a competitive relationship in CI pipes. Although interspecific relationships may help bacteria resist chlorine, the chlorine resistance was more reliant on dual-species groups and pipe materials. In CI pipes, the Microbacterium containing biofilm groups showed better chlorine resistance, whereas in PE pipes, most biofilm groups with Bacillus exhibited better chlorine resistance. The biofilm groups with more extracellular polymeric substance (EPS) secretion showed stronger chlorine resistance. The biofilm in the PE pipe is mainly protected by EPS, while both EPS and corrosion products shield the biofilms within CI pipe. These results supported that dual-species biofilms are affected by pipe materials and interspecific interactions and provided some ideas for microbial control in two typical pipe materials.

Present Understanding of Biodiversity of Anoxygenic Phototrophic Bacteria in the Relic Lake Mogilnoe (Kildin Island, Murmansk oblast, Russia)

The relic Lake Mogilnoe, separated from the Barents Sea by a sand and pebble dam, is located in the high Arctic on the Kildin island (Murmansk region). This lake is a classic example of a meromictic basin of marine origin. The data obtained during the 2018 expedition showed changes in the hydrochemical regime of the lake that have occurred over the past 20 years. Sulfide concentration in the monimolimnion of the lake was as high as 140 mg/L. A tendency for salinization of the surface waters to 7 g/L has been noted. The Lake Mogilnoe is characterized by a discrepancy between the halocline and thermocline levels. The chemocline zone in the lake is below the halocline level. In a narrow oxygen-containing layer between 3 and 7.5 m, aerobic microflora of the marine type and marine fauna were present. The bacterial plate was formed at the boundary of the sulfide layer at ~8 m and mainly consisted of green sulfur bacteria (GSB). Brown-colored GSB species containing bacteriochlorophyll e were predominant. The previously formed concept of anaerobic phototrophic bacteria (APB) biodiversity based on morphological characteristics was modified using metagenomic data obtained by analyzing DNA from two samples of lake water in the chemocline zone, and was also supplemented by identifying new GSB species. Molecular diagnostic data confirmed the absolute dominance of the brackish species of GSB Chlorobium phaeovibrioides. This is the first on isolation and identification of brown- and green-colored Prosthecochloris aestuarii morphotypes from Lake Mogilnoe and identified, as well as of bacteriochlorophyll c-containing Prosthecochloris sp. The taxonomic position of Pelodyction phaem, which was constantly present in the Lake Mogilnoe, is discussed in detail. Despite the partial isolation of the ecosystem of Lake Mogilnoe from the Barents Sea, the main properties of the dominant GSB species of GSB and Prosthecochloris aestuarii turned out to be similar to those of the phylotypes living in lakes on the White Sea coast of the, which remained connected with the Barents Sea.

Total Plate Count of Germs on Pear Surface Swabs During Washing with Fruit Washing Soap

The surface of the fruit is the first contamination of microorganisms on fruit with varying types and amounts. As many as 20% of cases of food poisoning caused by Salmonella typhi were recorded as a result of the consumption of fresh ready-to-eat products such as fruits. Washing the fruits that will be consumed is a good step, so a fruit washing soap product is used that can clean the fruits from these bacteria. Nonionic surfactants are cleaning agents found in fruit washing soaps that can remove bacteria on surfaces. The purpose of this study was to determine the difference in the total plate number of germs on the surface of pears when washing with fruit washing soap. The research method used in this research is descriptive method. The population is 50 soaps taken from 5 shops in the Harapan Baru market in Samarinda with different soap brands. The sample taken is 10% of the total population, namely 5 soaps. The sampling technique used purposive sampling. The study was carried out in July 2022. The method of examination used the examination of the TPC (Total Plate Count) with the pour plate method using PCA (Plate Count Agar) media. The data analysis used is univariate analysis which aims to explain the characteristics of each research variable by looking at the frequency distribution. The results showed that the number of bacteria before washing with fruit washing soap ranged from 4.4 x 100 CFU/cm2 to 1.4 x 101 CFU/cm2. Meanwhile, the number of bacteria after washing with fruit washing soap ranged from 0.4 x 100 CFU/cm2 to 3.4 x 100 CFU/cm2. The conclusion of this study is that there are differences in the number of total bacterial plate count on the surface of pears when washing with fruit washing soap.

Impact of Airborne Exposure to PM10 Increases Susceptibility to P. aeruginosa Infection.

The effects of exposure to airborne particulate matter with a size of 10 μm or less (PM10) on C57BL/6 mouse corneas, their response to Pseudomonas aeruginosa (PA) infection, and the protective effects of SKQ1 were determined. C57BL/6 mouse corneas receiving PBS or SKQ1 were exposed to control (air) or PM10 for 2 weeks, infected, and the disease was documented by clinical score, PMN quantitation, bacterial plate count, RT-PCR and Western blot. PBS-treated, PM10-exposed corneas did not differ at 1 day postinfection (dpi), but exhibited earlier (3 dpi) corneal thinning compared to controls. By 3 dpi, PM10 significantly increased corneal mRNA levels of several pro-inflammatory cytokines, but decreased IL-10, NQO1, GR1, GPX4, and Nrf2 over control. SKQ1 reversed these effects and Western blot selectively confirmed the RT-PCR results. PM10 resulted in higher viable bacterial plate counts at 1 and 3 dpi, but SKQ1 reduced them at 3 dpi. PM10 significantly increased MPO in the cornea at 3 dpi and was reduced by SKQ1. SKQ1, used as an adjunctive treatment to moxifloxacin, was not significantly different from moxifloxacin alone. Exposure to PM10 increased the susceptibility of C57BL/6 to PA infection; SKQ1 significantly reversed these effects, but was not effective as an adjunctive treatment.

Selection of starter lactic acid bacteria capable of forming biofilms on wooden vat prototypes for their future application in traditional Sicilian goat's milk cheese making

In this study, 327 presumptive lactic acid bacteria (LAB) were isolated from goats' milk acid curds produced at a Sicilian dairy farm with the aim to identify potential starter cultures for traditional cheeses. All isolates were first processed by randomly amplified polymorphic DNA (RAPD)-PCR analysis. This approach identified 63 distinct strains which were evaluated for their acidifying capacity. Only 15 strains specifically stood out for their acidification capacity and were identified through 16S rRNA gene sequencing as Lactococcus lactis (11 strains) Enterococcus faecalis (three strains), and Ligilactobacillus animalis (one strain). Notably, all 15 LAB isolates produced bacteriocin-like inhibitory substances and anti-biofilm compounds, against both planktonic and biofilm forms of Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli, and Staphylococcus aureus, albeit at varying levels. Among these 15 LAB, En. faecalis RGM25 and Lc. lactis RGM55, susceptible to five antibiotics tested, were put in contact with wooden vat prototypes, because all equipment used in traditional cheese production in Sicily are made of wood. Scanning electron microscopy and bacterial plate counts of the wooden vat prototypes showed the development of biofilms at levels of approximately 6.0 log CFU/cm2. Overall, this study contributes to establishing a custom-made LAB starter cultures with bio-preservatives properties for Sicilian cheese productions.

Inhibition of Salmonella enteritidis in homemade mayonnaise using oregano essential oil (Origanum vulgare)

The potential of oregano essential oil (OEO) as a natural antimicrobial agent to mitigate Salmonella spp. contamination in homemade mayonnaise made from raw eggs should be explored. This study aimed to assess the viability of Salmonella Enteritidis in homemade mayonnaise supplemented with OEO while also examining key quality parameters, including pH, titratable acidity, and the count of mesophilic aerobic microorganisms. In vitro experiments determined the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of OEO against two strains of Salmonella Enteritidis and one of Salmonella Typhimurium. Subsequently, homemade mayonnaise, intentionally contaminated with a Salmonella Enteritidis strain, was prepared, and OEO was added at concentrations of 0.5% and 1.0%. Bacterial plate counts for Salmonella spp. and mesophilic microorganisms, as well as acidity levels, were assessed at 0, 4, 8, and 24 hours of incubation at 30°C. The results indicated the in vitro efficacy of OEO, with an MIC of 0.5% and an MBC of 0.0625% against all strains. However, in homemade mayonnaise, Salmonella counts averaged 6.0 log CFU/g over the 24 hours at 30°C. Mesophilic microorganism counts also averaged 6.0 log CFU/g over 24 hours, similar to those of Salmonella. The pH values ranged from 4.5 to 5.1, and acidity levels remained between 0.31% and 0.39% throughout the 24 hours. In conclusion, oregano essential oil exhibited a bacteriostatic effect, effectively limiting the growth of Salmonella Enteritidis in homemade mayonnaise at the evaluated concentrations and time intervals.

Involvement of functional metabolism promotes the enrichment of antibiotic resistome in drinking water: Based on the PICRUSt2 functional prediction

Biofilters are the important source and sink of antibiotic resistance genes (ARGs) and antibiotic resistance bacteria (ARB) in the drinking water. Current studies generally ascribed the prevalence of BAR in biofilter from the perspective of gene behavior, i.e. horizontal gene transfer (HGT), little attentions have been paid on the ARGs carrier- ARB. In this study, we proposed the hypothesis that ARB participating in pollutant metabolism processes and becoming dominant is an important way for the enrichment of ARGs. To verify this, the antibiotic resistome and bacterial functional metabolic pathways of a sand filter was profiled using heterotrophic bacterial plate counting method (HPC), high-throughput qPCR, Illumina Hiseq sequencing and PICRUSt2 functional prediction. The results illustrated a significant leakage of ARB in the effluent of the sand filter with an average absolute abundance of approximately 102–103 CFU/mL. Further contribution analysis revealed that the dominant genera, such as Acinetobacter spp., Aeromonas spp., Elizabethkingia spp., and Bacillus spp., were primary ARGs hosts, conferring resistance to multiple antibiotics including sulfamethoxazole, tetracycline and β-lactams. Notably, these ARGs hosts were involved in nitrogen metabolism, including extracellular nitrate/nitrite transport and nitrite reduction, which are crucial in nitrification and denitrification in biofilters. For example, Acinetobacter spp., the dominant bacteria in the filter (relative abundance 69.97 %), contributed the majority of ARGs and 53.79 % of nitrite reduction function. That is, ARB can predominate by participating in the nitrogen metabolism pathways, facilitating the enrichment of ARGs. These findings provide insights into the stable presence of ARGs in biofilters from a functional metabolism perspective, offering a significant supplementary to the mechanisms of the emergence, maintenance, and transmission of BARin drinking water.

Evaluation of ATP bioluminescence for rapid determination of cleanliness of livestock trailers after a commercial wash.

Pathogens such as porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome (PRRSV), and E. coli are known to spread by contaminated vehicles and equipment. Pork producers have adopted trailer wash policies where each trailer is washed, disinfected, and dried before it can return to a farm. Cleanliness of livestock trailers after washing is determined by visual inspection rather than any objective method. Adenosine triphosphate (ATP) bioluminescence is used in many industries to provide real-time feedback on surface cleanliness through the detection of ATP from organic sources. That same technology may provide trailer wash facilities a way of objectively characterizing a livestock trailer's suitability to return to a farm after washing. Two ATP luminometers (3M Clean-Trace and Neogen AccuPoint) were used to estimate the correlation between ATP bioluminescence readings and aerobic bacterial plate counts (APCs) from sampled surfaces and to determine locations within a livestock trailer that can accurately estimate surface cleanliness. Five locations in livestock trailers were evaluated. Those locations included the nose access door (NAD), back door flush gate, rear side access door (RSAD), belly flush gate (BFG), and belly side access door (BSAD). There was a positive log-log association between the two luminometers (r = 0.59, P < 0.01). Every log unit increase in one unit, resulted in a 0.42 log increase (P < 0.01) in the other unit. ATP can come from bacteria, yeasts, molds, and manure. There was a poor association (r ≥ 0.10, P ≥ 0.02) between APCs and the ATP luminometers. Still, an increase in relative light units (RLUs) resulted in a corresponding increase in colony-forming units. The greatest area of surface contamination measured by APC was the NAD. RLUs were also greater in the NAD compared to the RSAD, the BFG, and the BSAD (P ≤ 0.01). Because APCs and luminometer RLUs provided similar outcomes, statistical process control charts were developed to determine control limits for RLUs. This provides real-time feedback to trailer wash workers in determining cleanliness outcomes for livestock trailers. These data suggest that ATP bioluminescence can be a reliable method to monitor cleaning effectiveness in livestock trailers. Bioluminescence is a monitoring tool that should be used in conjunction with microbial methods to monitor procedures for cleaning and disinfection.

Impact of Spirulina platensis biomass on the viability of Lactobacillus delbrueckii subsp. bulgaricus strain during the freeze-drying process.

In this work, we evaluated the protective capacity of Spirulina platensis biomass in preserving Lactobacillus delbrueckii subsp. bulgaricus WDCM 00102. The L. bulgaricus strain was freeze-dried in the presence of S. platensis biomass and the freeze-dried samples were then stored at 5 and 25°C for varying periods. Subsequently, the samples were rehydrated and bacterial plate counts were determined. The results indicate that a concentration of 12% S. platensis biomass was highly effective in preserving L. bulgaricus. Commercial products with higher S. platensis biomass content exhibited greater protective capacity. While S. platensis biomass is well-known for its prebiotic properties, its protective role has not been previously reported or thoroughly explored. This study demonstrates the protective capacity of S. platensis biomass in preserving L. bulgaricus, a strain particularly sensitive to preservation processes.

Molecular Characterisation of Gut Bacteria in Wista Rat After Green Tea Consumption

Green tea can influence the gut bacteria by either stimulating or hindering the growth of specific species. This experimental study was carried out in Rivers State, Nigeria to molecularly characterize gut bacteria in Wista rats after green tea consumption. Twenty-five (25) rats divided into five groups were used; each group had five (5) rats having an average weight range of 70g – 130g. After acclimatization of 2 weeks, groups (2, 3, 4 &amp; 5) were feed with green tea extract based on standard method using oral gavage with rat feed pellet and water for seven (7) days and fourteen (14) days respectively based on their body weights and group 1 (control) was fed with rat feed pellet and water only for same duration and their weights recorded. Stool samples were collected aseptically by pulling from each group into sterile stool sample bottles and sent to the laboratory for immediate analysis. Conventional microbiological methods of culturing and molecular methods were utilized for identification of isolates, total heterotrophic plate count and antibiotic susceptibility were also done. The data from this study were analysed using SPSS version 23, to survey difference in gut bacterial count of wista rats after fed with green tea, rat weight across the study groups, and the values were expressed as mean ± SD at a 5% alpha level. The study reported a statistical difference in bacterial plate count at (P≤0.05) in Groups 2, 3, 4, and 5 after 14 Days of Acclimatization, after 7 days of Treatment and after further 14 Days of Treatment. Group 1 showed no statistical significance at P=0.212. Furthermore, there was significant difference in weight comparison at (P≤0.05) in rats contained in all groups after 7 days and after further 14 days of treatment, rats in group 1 showed weight gain. There was weight loss in all the treatment groups (2 ,3, 4, and 5). Antibiotic-resistant assay pattern of the isolates showed multiple drugs resistance to all the antibiotics used with Bacillus and Enterobacter being the most resistant isolates. The molecular characterization and identification of the isolates revealed close relatedness to Staphylococcus arlettae, Enterobacter cloacae, Enterobacter cancerogenus, Acinetobacter nosocomialis, Comamonas testosterone, Klebsiella veriicola, Bacillus thuringiensis, Bacillus pumilus and Bacillus cereus, it showed that the molecular technique proved to be more specific and accurate than the convectional technique in the identification and characterization of the isolates. Also, the gut bacterial count of the rats that were treated with the tea were significantly raised indicating that the tea has the potential to influence the abundance and diversity of gut bacteria. As seen in this study, molecular characterisation of gut bacteria identifies bacteria upto their specie level and they are influenced by diet.

The Application of Bacteriophage and Photoacoustic Flow Cytometry in Bacterial Identification.

Infection with resistant bacteria has become an ever-increasing problem in modern medical practice. Bacteremia is a serious and potentially lethal condition that can lead to sepsis without early intervention. Currently, broad-spectrum antibiotics are prescribed until bacteria can be identified through blood cultures, a process that can take 2-3 days and is unable to provide quantitative information. Staphylococcus aureus (S. aureus) is a leading cause of bacteremia, and methicillin-resistant S. aureus (MRSA) accounts for more than a third of the cases. Other bacteria such as Clostridium difficile, Acinetobacter baumannii, and Carbapenem-resistant Enterobacteriaceae are becoming more prevalent and antibiotic-resistant. Rapid diagnostics for each of these superbugs has been a priority for health organizations around the world. Bacteriophages have evolved for millions of years to develop exquisite specificity in target binding using their host attachment proteins. Bacteriophages are viruses that infect bacteria. Bacteriophages use tail spikes, specialized attachment proteins, to bind specifically to their target bacterial cell surface proteins. We use bacteriophages and parts of bacteriophages as specific tags coupled with photoacoustic flow cytometry for the detection and quantification of bacteria. In photoacoustic flow cytometry, laser light is absorbed by particles under flow, and the ultrasound waves generated on the release of the energy are detected. Photoacoustics involves the detection of ultrasound waves resulting from laser irradiation. In photoacoustic flow cytometry, pulsed laser light is delivered to a sample flowing past a focused transducer, and particles that absorb laser light create a photoacoustic response. Bacteria can be tagged with dyed bacteriophage and processed through a photoacoustic flow cytometer where they are detected by the acoustic response. In this chapter, we describe the procedure and methods used to accomplish this. Often the limiting factor for the treatment of patients is the time spent waiting for results. It is our hope that the work presented in this chapter can be a foundation for future work and provide an ability to detect bacterial pathogens in blood cultures. Bacterial plate cultures and Gram staining are nineteenth-century technologies that have been the gold standards for decades, but current trends in resistant bacteria have necessitated a move toward more rapid and quantifiable diagnostic tools.

QUALITY AND SUSTAINABILITY OF PRODUCTION OF YOHURT FROM SOYABEANS, TIGER NUT, AND DATE

Yogurt, is also known as yoghurt, is one of the most known popularly fermented dairy products in the world, with a wide range of health benefits in addition to basic nutrition and was believed to have therapeutic powers and give long life to those who consumed it. This study aimed to evaluating the quality and suitability of production of yoghurt using blended tiger nut milk, soybeans milk and date milk. Proximate and microbial analysis was used to determine nutrient composition and quality of the produced yogurt. The study shows the mean scores ranges of proximate composition (moisture, ash, protein, fat, crude fibre and carbohydrate) of the formulated yoghurt: 75.83±1.44, 70.16±0.28, 81.00±1.73, 80.00±0.00, 0.61±0.02 – 0.76±0.02, 5.40±0.17 – 7.43±0.05, 5.33±0.03 – 6.40±0.00, 0.04±0.00 – 0.12±0.00. and for carbohydrate content, the mean score ranged from 4.27 ±1.81 – 17.16 ±0.54. The bacterial total plate count of the sample ranged from 1.6x102 – 9.7x103 cfu/ml. Sample A (1.3x102) had lowest growth while sample D (9.7x103) had highest growth. For appearance, the mean score ranged from 6.00±2.22 – 8.25±0.63, also for aroma, the mean score ranged from 6.45±2.41 – 7.50±0.94 and for overall acceptability, the mean score ranged from 6.40±2.37 – 8.00±0.64. This study revealed that soy milk, tiger nut milk and date palm juice produced can be effectively used for acceptable yogurt formulations..

Application of f-FeNC@GOx cascade enzyme nanomaterials in the healing of infected wounds

AimsBacterial infection is a significant factor contributing to the deterioration of wounds, and the misuse of antibiotics has exacerbated bacterial resistance. Therefore, there is an urgent need to develop a novel antibacterial strategy to replace conventional therapies. This study aims to construct a self-activated cascade reaction nanozyme, f-FeNC@GOx, which triggers a cascade reaction in the presence of glucose. This cascade reaction generates highly toxic hydroxyl radicals (OH), thereby achieving the goal of eliminating bacteria and promoting wound healing. Material and methodsIn vitro antibacterial experiments, bacterial spread plate method, Live/Dead staining, and crystal violet staining were conducted to analyze the antibacterial ability and mechanism of f-FeNC@GOx. In vivo experiments, a mouse wound model was established, and H&E and Masson staining of wound tissues were performed to assess the antibacterial activity of the f-FeNC@GOx in vivo. Key findingsThe in vivo and in vitro experiments confirmed that f-FeNC@GOx exhibited significant antibacterial effect against both Staphylococcus aureus and Escherichia coli in the presence of glucose. Furthermore, it showed optimal wound healing performance in the wound models. SignificanceThese findings suggested that f-FeNC@GOx was a novel and effective antibacterial nanomaterial, which provided a promising antibacterial strategy using nanoenzyme based cascade reaction.

Toxic response of antimony in the Comamonas testosteroni and its application in soil antimony bioremediation

Antimony (Sb) is toxic to ecosystems and potentially to public health via its accumulation in the food chain. Bioavailability and toxicity of Sb have been reduced using various methods for the remediation of Sb-contaminated soil in most studies. However, Sb-contaminated soil remediation by microbial agents has been rarely evaluated. In this study, we evaluated the potential for the use of Comamonas testosteroni JL40 in the bioremediation of Sb-contamination. Strain JL40 immobilized more than 30 % of the Sb(III) in solution and oxidized over 18 % to Sb(V) for detoxification. Meanwhile, strain JL40 responds to Sb toxicity through such as Sb efflux, intracellular accumulation, biofilm production, and scavenging of reactive oxygen species (ROS), etc. The results of the pot experiment showed the average Sb content of the brown rice was decreased by 59.1%, 38.8%, and 48.4%, for 1.8, 50, and 100 mg/kg Sb spiked soils, respectively. In addition, the results of plant, soil enzyme activity, and rice agronomic trait observations showed that the application of strain JL40 could maintain the health of plants and soil and improve rice production. The single-step and sequential extraction of Sb from rhizosphere soil showed that strain JL40 also plays a role in Sb immobilization and oxidation in the soil environment. During rice potted cultivation, bacterial community analysis and plate counting showed that the strain JL40 could still maintain 103 CFU/g after 30 days of inoculation. With phenotypic and differential proteomics analysis, strain JL40 conferred Sb(III) tolerance by a combination of immobilization, oxidation, efflux and scavenging of ROS, etc. Our study demonstrates the application of Sb-immobilizing and oxidizing bacteria to lower soil Sb and reduce accumulation of Sb in rice. Our results provide guidance for bacterial remediation of Sb-contaminated soil.

Drivers of Resistance in Uganda and Malawi (DRUM): a protocol for the evaluation of One-Health drivers of Extended Spectrum Beta Lactamase (ESBL) resistance in Low-Middle Income Countries (LMICs).

In sub-Saharan Africa (sSA), there is high morbidity and mortality from severe bacterial infection and this is compounded by antimicrobial resistance, in particular, resistance to 3rd-generation cephalosporins. This resistance is typically mediated by extended-spectrum beta lactamases (ESBLs). To interrupt ESBL transmission it will be important to investigate how human behaviour, water, sanitation, and hygiene (WASH) practices, environmental contamination, and antibiotic usage in both urban and rural settings interact to contribute to transmission of ESBL E. coli and ESBL K. pneumoniae between humans, animals, and the environment. Here we present the protocol for the Drivers of Resistance in Uganda and Malawi (DRUM) Consortium, in which we will collect demographic, geospatial, clinical, animal husbandry and WASH data from a total of 400 households in Uganda and Malawi. Longitudinal human, animal and environmental sampling at each household will be used to isolate ESBL E. coli and ESBL K. pneumoniae. This will be complimented by a Risks, Attitudes, Norms, Abilities and Self-Regulation (RANAS) survey and structured observations to understand the contextual and psychosocial drivers of regional WASH practices. Bacterial isolates and plate sweeps will be further characterised using a mixture of short-,long-read and metagenomic whole-genome sequencing. These datasets will be integrated into agent-based models to describe the transmission of EBSL resistance in Uganda and Malawi and allow us to inform the design of interventions for interrupting transmission of ESBL-bacteria.

Proof of concept of a new device for the insertion of peripheral venous catheters in aseptic conditions

According to the recommendations by the World Health Organization, the insertion of a peripheral venous catheter (PVC) must be an aseptic procedure while using non-sterile gloves. To overcome this apparent contradiction we have invented and patented (WO/2021/123482) a new device to be used during PVC insertion. The device permits the PVC placement in the vein while avoiding to directly touch the catheter with the fingertips. A total of 16 PVCs were inserted in the veins of a venipuncture anatomic training model while the operator was wearing non-sterile gloves. The gloves had been previously contaminated by embedding the fingertips in an agar plate inoculated with Staphylococcus epidermidis. Following insertion, the PVCs were sterilely removed and deposited on a bacterial culture plate. The tip cultures of PVCs that had been inserted with or without the use of the device were compared. Eight out of eight cultures (100.0%) were positive for S. epidermidis when the PVC had been inserted without using the device, whereas only one out of eight (12.5%) was positive when the device had been used. The single positive tip culture in the latter group corresponded to an insertion in which the operator had inadvertently touched the sterile part of the device while manipulating it. In conclusion, an auxiliary novel device allows the aseptic insertion of PVCs while the operator is wearing non-sterile gloves. Regulatory institutions should consider to recommend the insertion of PVCs by means of devices aimed at avoiding the contamination of the catheter.

Insight study on synthesis and antibacterial mechanism of silver nanoparticles prepared from indigenous plant source of Jharkhand

BackgroundThe Ag-NPs by green synthesis has a notable interest because of their eco-friendliness, economic views, feasibility, and applications in a wide range. Herein, native plants of Jharkhand (Polygonum plebeium, Litsea glutinosa, and Vangueria spinosus) were selected for the current work of Ag-NP synthesis and further antibacterial activity. Green synthesis was performed for Ag-NPs using Silver nitrate solution as precursor and the dried leaf extract performs as a reductant and stabilizer here. ResultVisually Ag-NP formation was observed along with a colour change and confirmed by UV-visible spectrophotometry on which an absorbance peak occurs at around 400–450nm. Further characterization was done on DLS, FTIR, FESEM, and XRD. Size around 45–86 nm of synthesized Ag-NPs was predicted through DLS. The synthesized Ag-NPs exhibited significant antibacterial activity against Bacillus subtilis (Gram-positive bacteria) and Salmonella typhi (Gram-negative bacteria). The finest antibacterial activity was disclosed by the Ag-NPs synthesized by Polygonum plebeium extract. The diameter of the zone of inhibition in the bacterial plate measured was 0–1.8 mm in Bacillus and 0–2.2 mm in Salmonella typhi. Protein-Protein interaction study was performed to study the effect of Ag-NPs towards different antioxidant enzyme system of bacterial cell. ConclusionPresent work suggest the Ag-NPs synthesized from P. plebeium were more stable for long term and might have prolonged antibacterial activity. In the future, these Ag-NPs can be applied in various fields like antimicrobial research, wound healing, drug delivery, bio-sensing, tumour/cancer cell treatment, and detector (detect solar energy). Graphical AbstractSchematic representation of Ag-NPs green synthesis, characterization, antibacterial activity and at the end, in silico study to analyse the mechanism of antibacterial activity▪

SG-APSIC1154: Evaluation of disposable antimicrobial curtains in an ambulatory cancer center

Objectives: The prevention of nosocomial infection is a challenge for all healthcare institutions. Privacy curtains are often changed infrequently, and they are difficult to clean. Contaminated curtains can be touched by healthcare providers and patients, which may result in indirect transmission of infectious disease. Hence, we evaluated the impact of the antimicrobial properties of disposable curtains and their cost-effectiveness. Methods: This descriptive exploratory study was conducted in an ambulatory cancer center in 2017. Privacy curtains were assigned to 2 cohorts, labelled E1 and E2. They were placed in the clinical areas for 6–12 months. Moist swab samples for MRSA, VRE, and CP-CRE cultures were obtained from the leading edges of the curtains during the evaluation period. Also, 10-cm × 10-cm swatches were cut from the high-touch areas of curtains and were tested for total aerobic count on the first of the month and quarterly thereafter. Results: All bacterial culture swabs obtained from the E1 and E2 cohorts of curtains were negative. The total bacterial plate count results from E1 curtains were negative for up to 1 year. However, the total bacterial plate count results for E2 curtains were positive in the sixth month. Using disposable curtains yielded an annual cost saving of ~50%. Conclusions: The use of appropriate impregnated antimicrobial disposable curtains can improve patient safety in the clinical areas. These curtains may eliminate potential sources of infection and thereby decrease the rate of nosocomial infection. They also save significant institutional costs by reducing frequent laundry and manpower requirements needed for the installation of curtains.

ВИДОВОЕ БОГАТСТВО ИНФУЗОРИЙ МАЛОГО ЗАБОЛАЧИВАЮЩЕГОСЯ ВОДОЕМА: ОБЩИЕ ПРОБЛЕМЫ СОХРАНЕНИЯ ИХ БИОРАЗНООБРАЗИЯ

This article presents the results of the fi rst study of the species composition of ciliates from the polyhumous lake Mohovoye, located in the Volga-Kama State Natural Biosphere Reserve; discusses the general issues of the need to organize the conservation and protection of protozoa and their habitats; provides a brief overview of the experience accumulated in the world on this issue. The aim of the work was to identify new and rare species of ciliates, to describe their autecological and distributional features as a descriptive basis for further identifi cation of potential diversity. 53 species have been recorded in the deep-water part of the lake, while there are species that have not even been identifi ed to the genus level. Lacrymaria cf. sapropeliсa Kahl, 1927, Trichospira inversa (Claparède &amp; Lachmann, 1858), two species from the family Spathidiidae, as well as the main dominant Pseudoblepharisma tenue var. viride (Kahl, 1926) have not previously been recorded in this region. Their detection is more likely due to the low level of study of such undisturbed habitats than to the endemism of these species. The uniqueness of the lake and the whole complex of ciliates species lies in the signifi cant magnitude of the maximum abundance – 753.7 million cells/m3 ; 53-75% of the abundance was formed by P. tenue var. viride (Kahl, 1926), which is a rare species in other waterbodies. In general, mainly mixotrophic ciliares form a very narrow and high, like a “bacterial plate” abundance maximum. The problem of the conservation of the ciliates biodiversity lies in the underestimation of their importance, due to their inconspicuousness and cosmopolitanism; the low attractiveness of small reservoirs as “pockets of diversity” for limnologists and the lack of well-trained specialists in the systematics of ciliates who can be able to competently combine morphological and molecular genetic research methods.

Estimating microbial population data from optical density.

The spectrophotometer has been used for decades to measure the density of bacterial populations as the turbidity expressed as optical density-OD. However, the OD alone is an unreliable metric and is only proportionately accurate to cell titers to about an OD of 0.1. The relationship between OD and cell titer depends on the configuration of the spectrophotometer, the length of the light path through the culture, the size of the bacterial cells, and the cell culture density. We demonstrate the importance of plate reader calibration to identify the exact relationship between OD and cells/mL. We use four bacterial genera and two sizes of micro-titer plates (96-well and 384-well) to show that the cell/ml per unit OD depends heavily on the bacterial cell size and plate size. We applied our calibration curve to real growth curve data and conclude the cells/mL-rather than OD-is a metric that can be used to directly compare results across experiments, labs, instruments, and species.