Comparison of CHROMagar Orientation Medium with Traditional Methods in Urinary Tract Infection Cultures

BACKGROUND

Urinary tract infections (UTIs) are the most common infections in adults, and urine culture is the parameter that uses the most time and cost in microbiology laboratories. For this reason, the selection of fast and cost-effective methods in the evaluation of urine samples is one of the priority issues of microbiology laboratories. The aim of this study was to investigate the compatibility and cost-effectiveness of routinely used Blood Agar (BA), Eosin Methylene Blue (EMB) medium, and CHROMagar Orientation Medium (CO Medium) in the identification of microorganisms in urine samples.

METHODS

Consecutive urine samples (n: 700) sent to our laboratory were simultaneously inoculated onto BA/EMB media and CO medium. Urine samples were evaluated after 18 - 24 hours of incubation at 37℃ and the compatibility of the two methods was compared. The use of 104 Gram stains, 198 biochemical tests, and 9 identification kits was required with BA/EMB agar.

RESULTS

When 104 colonies with single growth were evaluated, presumptive identification with CO medium was found to be 100% compatible with the VITEK 2 system. The most isolated 62 Escherichia coli (E. coli) colonies gave dark pink-red color and were found to be fully compatible with the VITEK 2 system. Compatibility of BA and EMB medium evaluations with VITEK 2 system; E. coli (n: 62), KES group (n: 26), Pseudomonas spp. (n: 6) and Proteus spp. For (n: 2), it was determined as 69.3%, 57.69%, 100%, and 100%, respectively. According to the results of our study, when BA/EMB and CO Medium methods were compared, 182 Euro (€) savings were achieved in 700 urine cultures with CO Medium. It was estimated that the amount of savings could be 15,600 € per year.

CONCLUSIONS

CHROMagar Orientation Medium method can be used routinely with its advantages such as being cost-effective, reducing the workload, and not requiring additional operations. CHROMagar Orientation Medium can also be considered as an easily accessible method and opportunity that does not require infrastructure and trained personnel, especially for laboratories with low test capacity and having problems with the supply of com-mercial kits and automated systems.

Understanding the significance of microbiota recovered from health care surfaces

BACKGROUND

Microbial contamination of hospital surfaces remains despite adherence to routine disinfection. Our study demonstrates bioburden from various types of hospital high-touch surfaces and the pathogenicity of all bacteria recovered.

METHODS

Several high-touch hospital surfaces from a single medical-surgical unit were sampled and cultured using replicate organism detection and counting (RODAC) Tryptic Soy agar plates. Colonies were then subcultured to blood agar plates and speciated using MALDI-TOF. The local microbiology laboratory database was queried for any clinical isolate match with the environmental samples recovered.

RESULTS

Manikins, bed rails, and workstations-on-wheels were the most contaminated surfaces with the largest variety of bacteria isolated from manikins and bed rails. A total of 60 different types of pathogens were isolated, 18 of which were well-known pathogens, and 7 were classified as important in the health care setting by CDC. Our clinical microbiology laboratory identified 29 of 60 hospital surface bacteria in clinical isolates. Urine, soft tissue, and blood were the most common sources of clinical isolates.

CONCLUSIONS

Surfaces in the health care environment harbor both well-known and not-so-well-known human pathogens. Several not-so-well-known pathogens are skin flora or environmental bacteria, which in the right setting, can become pathogenic and cause diseases including meningitis, brain abscess, endocarditis, and bacteremia.

Effect and characterization of konjac glucomannan on xanthan gum/κ-carrageenan/agar system

A mixed polysaccharide system is an important strategy to improve the performance of a single polysaccharide. Herein, quaternary polysaccharide gels were prepared by konjac glucomannan (KGM), xanthan gum (XG), κ-carrageenan (κ-CA), and agar (AR). The effects of KGM were evaluated by combining water holding capacity (WHC), rheological analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and texture profile analysis (TPA). More KGM gradually increased the springiness of the compounded gels. WHC increased and then decreased with the addition of KGM, performing best at KGM4 (KGM: κ-CA:XG:AR = 2:2:1:2). Rheological analysis showed that the compounded gels exhibited a pseudoplastic characteristic of shear thinning, KGM endowed the gel with a stronger shear thinning behavior and improved the solid-like nature of the gels at high temperatures. The thermal stability of the composite gel was improved by the participation of KGM. FTIR analysis showed that the interactions were mainly related to intermolecular hydrogen bonds and acetyl groups. The microscopic morphology of KGM4 was significantly continuous, smooth, and compact, exhibiting the best practical performance and taking the maximum advantage.

Defining Small Intestinal Bacterial Overgrowth by Culture and High Throughput Sequencing

BACKGROUND& AIMS

Despite accelerated research in small intestinal bacterial overgrowth (SIBO), questions remain regarding optimal diagnostic approaches and definitions. Here, we aim to define SIBO using small bowel culture and sequencing, identifying specific contributory microbes, in the context of gastrointestinal symptoms.

METHODS

Subjects undergoing esophagogastroduodenoscopy (without colonoscopy) were recruited and completed symptom severity questionnaires. Duodenal aspirates were plated on MacConkey and blood agar. Aspirate DNA was analyzed by 16S ribosomal RNA and shotgun sequencing. Microbial network connectivity for different SIBO thresholds and predicted microbial metabolic functions were also assessed.

RESULTS

A total of 385 subjects with <103 colony forming units (CFU)/mL on MacConkey agar and 98 subjects with ≥103 CFU/mL, including ≥103 to <105 CFU/mL (N = 66) and ≥105 CFU/mL (N = 32), were identified. Duodenal microbial α-diversity progressively decreased, and relative abundance of Escherichia/Shigella and Klebsiella increased, in subjects with ≥103 to <105 CFU/mL and ≥105 CFU/mL. Microbial network connectivity also progressively decreased in these subjects, driven by the increased relative abundance of Escherichia (P < .0001) and Klebsiella (P = .0018). Microbial metabolic pathways for carbohydrate fermentation, hydrogen production, and hydrogen sulfide production were enhanced in subjects with ≥103 CFU/mL and correlated with symptoms. Shotgun sequencing (N = 38) identified 2 main Escherichia coli strains and 2 Klebsiella species representing 40.24% of all duodenal bacteria in subjects with ≥103 CFU/mL.

CONCLUSIONS

Our findings confirm ≥103 CFU/mL is the optimal SIBO threshold, associated with gastrointestinal symptoms, significantly decreased microbial diversity, and network disruption. Microbial hydrogen- and hydrogen sulfide-related pathways were enhanced in SIBO subjects, supporting past studies. Remarkably few specific E coli and Klebsiella strains/species appear to dominate the microbiome in SIBO, and correlate with abdominal pain, diarrhea, and bloating severities.

Phytochemical screening and antimicrobial activity of Polygala sadebeckiana Gürke extracts on bacterial isolates from Wound samples of patients with "Shimetere"

BACKGROUND

Modern medicine is not the choice of patients with "shimetere" in the Gurage community owing to their perception of 'parenteral medication use severely aggravates the disease'. For this reason, the root part of Polygala sadebeckiana Gürke is commonly utilized as traditional medicine in the management of the disease. The aim of this study was to evaluate the antimicrobial activity of Polygala sadebeckiana Gürke extract on bacterial isolates from wound samples of patients with "Shimetere".

METHODS

The agar well diffusion method was used to evaluate antibacterial activity, and the agar dilution method was utilized to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MICs). The crude extract was tested against isolated bacteria at concentrations of 25, 50, 75 and 100 mg/mL in triplicate (3x). The positive controls were azithromycin (15 µg) and cloxacillin disk (5 µg), and the negative control was dimethylsulfoxide (5%). The group mean comparisons were made using one-way ANOVA at a significance level of p < 0.05, and the results are presented as the mean ± standard deviation. The presence of secondary metabolites from crude extract was checked by standard testing procedures.

RESULTS

S. aureus and S. pyrogen were the two identified bacteria from 9 (60%) and 3 (20%) wound samples, respectively. All identified bacterial strains were susceptible to the reference antibiotics. Tannins and saponins were the most abundant secondary metabolites found in the crude extracts. The average inhibition zones of the plant extracts with 100, 75, 50 and 25 mg/mL concentrations were 27, 20.33, 15.25, and 11.96 mm (p < 0.000) for S. aureus and 30.02, 24.50, 19.07, and 15.77 mm (p < 0.000) for S. pyrogen bacteria, respectively. The MIC and MBC of the crude extract were 1.67 and 10 mg/mL for S. aureus and 0.98 and 4 mg/mL for S. pyrogen.

CONCLUSION

Polygala sadebeckiana Gürke contained significant tannins and saponins as secondary metabolites and had antibacterial activities against isolated bacteria (S. aureus and S. pyrogen) from "Shimetere". The potential mechanism of antibacterial action of the plant extract was cell wall synthesis inhibition.

Molecular detection of Trichomonas vaginalis from vaginal swabs collected in Copan TransystemTM M40 Amies media using the Hologic Panther test system

We evaluated the performance of the Copan Transystem™ M40 collection swab containing Amies agar gel ('M40') on the Aptima® TV Assay for the detection of Trichomonas vaginalis ribosomal RNA (rRNA) using a novel 'Single Swab' molecular workflow. Overall agreement between Aptima TV Assay and wet mount microscopy was 99 % (152/153; 95 % confidence interval 0.9806 to 1.006), a positive agreement of 100 % and negative agreement of 99 %. Limit of detection for microscopy was 100,000-fold higher compared to molecular. T. vaginalis rRNA was stable in M40 under room-temperature and refrigerated conditions. The 'Single Swab' workflow resulted in a 57.4 % reduction in hands-on time, and a 5-fold increase in technologist productivity. Post-molecular test implementation analysis demonstrated a 2.27-fold increase in T. vaginalis positivity rate compared to the pre-implementation method. Collectively, our 'Single Swab' molecular testing approach was non-inferior to wet mount microscopy with the added benefits of a simplified and more efficient workflow.

Sequestration of Cr (VI) from water using agar-polyvinyl alcohol based cation exchanger

Present study focuses on the use of a biodegradable and cost-effective cation exchanger for removal of Cr (VI) metal ions from water sources. Semi-IPN was prepared through grafting of acrylamide onto agar-polyvinyl alcohol backbone in presence of boric acid and ammonium per sulphate as crosslinker-initiator system. Graft copolymer was converted to cation exchanger through phosphorylation. Characterization was done using methods such as FTIR, SEM-EDX and XRD. Semi-IPN exhibited higher thermal resistance. The findings revealed that the optimum conditions for Cr (VI) removal are pH = 4.0; contact time (min) = 360; adsorbent dose (mg) = 125 and metal ion concentration(mg/L) =2. The adsorption kinetics of Cr (VI) ions are best fit by the pseudo second order kinetic with 0.99 R2 and Kf (rate constant) was found to be 0.97 thereby supporting the Freundlich isotherm. The adsorption isotherm models used in this study were consistent with the Freundlich model, but the pseudo second order model was the most accurate description of the adsorption kinetics. The present investigation showed an excellent potential with 85 % adsorption capacity for the removal of Cr (VI). Moreover, reusability studies showed that the cation exchanger can be used effectively up to four cycles.

Effects of spore purity on the wet heat resistance of Clostridium perfringens, Bacillus cereus and Bacillus subtilis spores

Heat resistance of spores of Clostridium perfringens 8238 (Hobbs Serotype 2), Bacillus cereus NCTC 11143 (4810/72), and Bacillus subtilis PS533, an isogenic derivative of strain PS832 (a 168 strain) was determined in ground beef at 95 °C. Spore purification was by centrifugation and washing with sterile distilled water (dH2O), followed by sonication and then Histodenz centrifugation for B. subtilis and C. perfringens, and centrifugation and washing with sterile dH2O followed by Histodenz centrifugation for B. cereus. Bags containing inoculated beef samples were submerged in a temperature-controlled water bath and held at 95 °C for predetermined lengths of time. Surviving spore populations were enumerated by plating on mannitol egg yolk polymyxin agar (MYP) agar plates for B. cereus and B. subtilis, and on tryptose-sulfite-cycloserine agar (TSC) agar plates for C. perfringens. Survivor curves were fitted to linear, linear with tail, and Weibull models using the USDA Integrated Pathogen Modeling Program (IPMP) 2013 software. The Weibull model provided a relatively better fit to the data since the root mean square error (RMSE), mean square error (MSE), sum of squared errors (SSE), and Akaike information criterion (AIC) values were lower than the values obtained using the linear or the linear with tail models. Additionally, the Weibull model accurately predicted the observed D-values at 95 °C for the three spore-formers since the accuracy factor (Af) values ranged from 1.03 to 1.08 and the bias factor (Bf) values were either 1.00 or 1.01. Times at 95 °C to achieve a 3-log reduction decreased from 206 min for C. perfringens spores purified with water washes alone to 191 min with water washes followed by sonication and Histodenz centrifugation, from 7.9 min for B. cereus spores purified with water washes alone to 1.4 min with water washes followed by Histodenz centrifugation, and from 20.6 min for B. subtilis spores purified with water washes alone to 6.7 min for water washes followed by sonication and Histodenz centrifugation. Thermal-death-time values reported in this study will assist food processors to design thermal processes to guard against bacterial spores in cooked foods. In addition, clearly spore purity is an additional factor in spore wet heat resistance, although the cause of this effect is not clear.

Synthesis of Hydrazide Derivative of Betulinic Acid, Its Organometallic Complexes, Characterization and Bioassay

Betulinic acid and its derivatives comprehend an immense prospective toward the development of cytotoxic, antiviral, antimicrobial and antioxidant agents. Cisplatin (cytotoxic drug) divert the attentions to develop organometallic compounds with pronounced biological activities. The current study was aimed for the first time to synthesize, characterize and evaluate biologically a series of metal (Fe, Cu, Zn, Sn and Sb) complexes of betulinic acid hydrazide. First step involved the formation of hydrazide derivative of betulinic acid (ligand) by modification at C-28 carboxylic acid moiety of betulinic acid with hydrazine followed by the synthesis of its metal complexes using salts of different metals (Fe, Cu, Zn, Sn and Sb). Physical state, melting point, Fourier-transform infrared (FT-IR) and 1 H nuclear magnetic resonance (1 H-NMR) spectral techniques were used to characterized the ligand and its metal complexes. Agar well diffusion method and agar tube dilution assay were performed to evaluate its antibacterial and antifungal activities respectively. DPPH assay was carried out to develop antioxidant properties by the reported methods.

Concerning the presumptive identification of Candida kefyr on Uriselect™4 agar

OBJECTIVE

Non-albicans Candida species, such as Candida kefyr, are emerging pathogens. Chromogenic media are highly useful for the diagnosis of urinary tract infections (UTIs). The aim was to describe the behavior of this specie on a non-specific chromogenic medium.

METHODS

A retrospective study of cases of candiduria detected in the Microbiology laboratory of the Virgen de las Nieves Hospital in Granada (Spain) between 2016 and 2021 (N=2,130). Urine samples were quantitatively seeded on non-selective UriSelect™4 chromogenic agar.

RESULTS

Between 2016 and 2021, C. kefyr was the seventh most frequent Candida species responsible for candiduria in our setting (n=15). The macroscopic appearance of C. kefyr colonies, punctiform and bluish, allowed the direct identification of these microorganisms.

CONCLUSIONS

This study provides the first description of the specific behavior of C. kefyr on UriSelect™4 agar, which differentiates it from other Candida species based on its enzymatic characteristics.

Effect of the pre-crosslinking of Ba2+ ions on wet spinning of agar fibers

Decreased coagulation bath concentration and difficult recovery are classical issues observed during the wet spinning of fibers. In this paper, a novel method was presented for preparing environment-friendly agar fibers using deionized water as the coagulation and stretch baths. The addition of Ba2+ into the spinning solution increased the crosslinking time and improved the performance of spinning solution. The results showed that the introduction of Ba2+ in the spinning solution increased the viscosity of the spinning solution. Particularly, when the concentration of BaCl2 in the spinning solution was 7 wt%, the viscosity increased to 39.29 Pa·s, which made the molecular chain arrangement of agar more compact and ordered and promoted the gelation transformation of the spinning solution, resulting in an increase in the gel temperature from 0.2 °C (Ba-0/agar) to 5.4 °C (Ba-7/agar). The spinning solution was more conducive to the formation of fibers in deionized water. In addition, the physical and chemical properties of agar fibers were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, tensile testing, and scanning electron microscopy. The results showed that the use of deionized water as the coagulation bath can improve the color of fiber and solve the problem of fiber adhesion, whereas the mechanical strength of agar fibers with pre-cross-linking metal ions was also improved. For example, the breaking strength of Ba-7/agar/DIW was 0.73 cN/dtex while the breaking strength of Ba-0/agar/DIW was only 0.62 cN/dtex.

Investigations on correlations between changes of optical tissue properties and NMR relaxation times

BACKGROUND

Accurate light dosimetry is a complex remaining challenge in interstitial photodynamic therapy (iPDT) for malignant gliomas. The light dosimetry should ideally be based on the tissue morphology and the individual optical tissue properties of each tissue type in the target region. First investigations are reported on using NMR information to estimate changes of individual optical tissue properties.

METHODS

Porcine brain tissue and optical tissue phantoms were investigated. To the porcine brain, supplements were added to simulate an edema or high blood content. The tissue phantoms were based on agar, Lipoveneous, ink, blood and gadobutrol (Gd-based MRI contrast agent). The concentrations of phantom ingredients and tissue additives are varied to compare concentration-dependent effects on optical and NMR properties. A 3-tesla whole-body MRI system was used to determine T1 and T2 relaxation times. Optical tissue properties, i.e., the spectrally resolved absorption and reduced scattering coefficient, were obtained using a single integrating sphere setup. The observed changes of NMR and optical properties were compared to each other.

RESULTS

By adjusting the NMR relaxation times and optical tissue properties of the tissue phantoms to literature values, recipes for human brain tumor, white matter and grey matter tissue phantoms were obtained that mimic these brain tissues simultaneously in both properties. For porcine brain tissue, it was observed that with increasing water concentration in the tissue, both NMR-relaxation times increased, while µa decreased and µs' increased at 635 nm. The addition of blood to porcine brain samples showed a constant T1, while T2 shortened and the absorption coefficient at 635 nm increased.

CONCLUSIONS

In this investigation, by changing sample contents, notable changes of both NMR relaxation times and optical tissue properties have been observed and their relations examined. The developed dual NMR/optical tissue phantoms can be used in iPDT research, clinical training and demonstrations.

Agreement of methods to assess antimicrobial susceptibility using Escherichia coli isolates as target models

Antimicrobial susceptibility tests (AST) conducted in vitro offer a range of methods to assess the antimicrobial resistance (AMR) of microorganisms. Escherichia coli, a widely distributed bacterium, is closely linked to the issue of AMR. In this way, the present study aimed to assess the agreement among different in vitro AST methods, including disk diffusion in agar, broth dilution, and agar dilution method. A total of 100 E. coli isolates were analyzed for their resistance levels against six antibiotics: amoxicillin, ceftiofur, ciprofloxacin, chloramphenicol, tetracycline, and sulfamethoxazole + trimethoprim, using the aforementioned AST methods. Standard breakpoint values were employed to classify isolates as resistant, intermediate, or susceptible, and comparisons among the AST methods were conducted by McNemar's test (P < .05). The obtained data demonstrated equivalence among the AST methods, highlighting the reliability of these standardized classical methodologies. This standardization aids in preventing the inappropriate use of antimicrobials and the dissemination of antimicrobial-resistant microorganisms.

Identification of fungi isolated from commercial bumblebee colonies

Fungi can have important beneficial and detrimental effects on animals, yet our understanding of the diversity and function of most bee-associated fungi is poor. Over 2 million bumblebee colonies are traded globally every year, but the presence and transport of viable fungi within them is unknown. Here, we explored whether any culturable fungi could be isolated from commercial bumblebee nests. We collected samples of various substrates from within 14 bumblebee colonies, including the honey, honey cup wall, egg cup wall, and frass then placed them on agar and recorded any growth. Fungal morphotypes were then subcultured and their ITS region sequenced for identification. Overall, we cultured 11 fungal species from the various nest substrates. These included both pathogenic and non-pathogenic fungi, such as Aspergillus sp., Penicillium sp., and Candida sp. Our results provide the first insights into the diversity of viable fungal communities in commercial bumblebee nests. Further research is needed to determine if these fungi are unique to commercial colonies or prevalent in wild bumblebee nests, and crucially to determine the ecological and evolutionary implications of these fungi in host colonies.

Prevalence and antimicrobial susceptibility profile of bacteria isolated from the hands of housemaids in Jimma City, Ethiopia

Introduction

Bacterial pathogens continue to be a major cause of foodborne gastroenteritis in humans and remain a public health problem. Housemaids operating inside a kitchen could be the source of infection and may transmit disease-inflicting pathogens through contaminated hands.

Objective

This study aimed to assess the prevalence and antimicrobial susceptibility profile of bacteria isolated from the hands of housemaids in Jimma City, Ethiopia.

Methods

A laboratory-based cross-sectional study was employed among 234 housemaids. Hand swab samples from the dominant hand of the study participants were collected under sterile conditions following standard operating procedures. Then, in the laboratory, the swabs were inoculated aseptically using streak-plating methods on the growth media, such as mannitol salt agar [Staphylococcus aureus and coagulase-negative staphylococci], MacConkey agar [Klebsiella species and Proteus species], salmonella-shigella agar [Salmonella species and Shigella species], and eosin methylene blue agar [Escherichia coli (E. coli)]. In addition, a set of biochemical tests was applied to examine bacterial species. Data were double-entered into EpiData version 3.1 and then exported to the Statistical Package for Social Science (SPSS) version 26 for further analysis. Descriptive analyses were summarized using frequency and percentage.

Results

The proportion of housemaids' hands containing one or more positive bacterial isolates was 72% (95% CI: 66.2, 77.8). The dominant bacterial isolates were Staphylococcus aureus (31.6%), Escherichia coli (21.3%), Salmonella species (1.3%), Shigella species (6.7%), Klebsiella species (23.1%) and Proteus species (14.7%). Fingernail status (AOR =15.31, 95% CI: 10.372, 22.595) and the removal of a watch, ring, and bracelet during hand washing (AOR = 20.844, 95% CI: 2.190, 9.842) were significantly associated with the prevalence of bacterial isolation. Most Staphylococcus aureus isolates were susceptible to chloramphenicol (98.6%). Escherichia coli isolates were susceptible to tetracycline (75%), ceftriaxone (79.2%), chloramphenicol (87.5%), and ceftazidime (77.1%). Eighty percent of isolated Shigella species were susceptible to chloramphenicol and gentamicin respectively. In addition, Klebsiella and Proteus species exhibited high susceptibility to chloramphenicol. However, their isolates showed resistance against a number of the tested antimicrobials. Staphylococcus aureus isolates (28.2%) were resistance to tetracycline. Moreover, One-quarter of Escherichia coli isolates were resistance to tetracycline, ceftriaxone, chloramphenicol, and ceftazidime. Whereas 46.7% and 48.5% of isolated Shigella species and Proteus species were resistance to tetracycline and ceftriaxone.

Conclusion

The hands of housemaids are important potential sources of pathogenic bacteria that would result in the potential risk of foodborne diseases. Most bacteria isolates were resistant to tetracycline, ceftriaxone, and ceftazidime. Therefore, practicing good hand hygiene helps to prevent and control the spread of antimicrobial-resistant microbes.

Mass spectrometry imaging of natural carbonyl products directly from agar-based microbial interactions using 4-APEBA derivatization

Aliphatic carboxylic acids, aldehydes, and ketones play diverse roles in microbial adaptation to their microenvironment, from excretion as toxins to adaptive metabolites for membrane fluidity. However, the spatial distribution of these molecules throughout biofilms and how microbes in these environments exchange these molecules remain elusive for many of these bioactive species due to inefficient molecular imaging strategies. Herein, we apply on-tissue chemical derivatization (OTCD) using 4-(2-((4-bromophenethyl)dimethylammonio)ethoxy)benzenaminium dibromide (4-APEBA) on a co-culture of a soil bacterium (Bacillus subtilis NCIB 3610) and fungus (Fusarium sp. DS 682) grown on agar as our model system. Using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), we spatially resolved more than 300 different metabolites containing carbonyl groups within this model system. Various spatial patterns are observable in these species, which indicate possible extracellular or intercellular processes of the metabolites and their up- or downregulation during microbial interaction. The unique chemistry of our approach allowed us to bring additional confidence in accurate carbonyl identification, especially when multiple isomeric candidates were possible, and this provided the ability to generate hypotheses about the potential role of some aliphatic carbonyls in this B. subtilis/Fusarium sp. interaction. The results shown here demonstrate the utility of 4-ABEBA-based OTCD MALDI-MSI in probing interkingdom interactions directly from microbial co-cultures, and these methods will enable future microbial interaction studies with expanded metabolic coverage.IMPORTANCEThe metabolic profiles within microbial biofilms and interkingdom interactions are extremely complex and serve a variety of functions, which include promoting colonization, growth, and survival within competitive and symbiotic environments. However, measuring and differentiating many of these molecules, especially in an in situ fashion, remains a significant analytical challenge. We demonstrate a chemical derivatization strategy that enabled highly sensitive, multiplexed mass spectrometry imaging of over 300 metabolites from a model microbial co-culture. Notably, this approach afforded us to visualize over two dozen classes of ketone-, aldehyde-, and carboxyl-containing molecules, which were previously undetectable from colonies grown on agar. We also demonstrate that this chemical derivatization strategy can enable the discrimination of isobaric and isomeric metabolites without the need for orthogonal separation (e.g., online chromatography or ion mobility). We anticipate that this approach will further enhance our knowledge of metabolic regulation within microbiomes and microbial systems used in bioengineering applications.

[Establishment and Evaluation of a Resazurin-Based Microdilution Assay for Microbial Sensitivity Test of Neisseria gonorrhoeae]

Objective

To establish and evaluate a microbial sensitivity test method for Neisseria gonorrhoeae based on resazurin coloration.

Methods

Based on the broth microdilution method, resazurin was added as a live bacteria indicator. WHO G, a WHO gonococcal reference strain, was used to optimize the incubation time for resazurin-stained bacteria and the color change was visually observed to obtain the results. Agar dilution method (the gold standard) and resazurin-based microdilution assay were used to determine the minimum inhibitory concentration (MIC) of azithromycin, ceftriaxone, and spectinomycin for 3 reference strains and 32 isolates of Neisseria gonorrhoeae. The results were analyzed based on essential agreement (EA), which reflected the consistency of the MIC values, category agreement (CA), which reflected the consistency in the determination of drug resistance, intermediary, and sensitivity, very major error (VME), which reflected false sensitivity, and major error (ME), which reflected pseudo drug resistance, to evaluate the accuracy of resazurin-based microdilution assay as a microbial sensitivity test of of Neisseria gonorrhoeae. CA and EA rates≥90% and VME and ME rates≤3% were found to be the acceptable performance rates.

Results

The results obtained 6 hours after resazurin was added were consistent with those of the agar dilution method and the resazurin-based microdilution assay was established accordingly based on this parameter. The EA of resazurin-based microdilution assay for measuring the MIC results of azithromycin, ceftriaxone, and spectinomycin was 97.1%, 91.5%, and 94.3%, respectively, and the CA was 88.6%, 94.3%, and 94.3%, respectively. The VME was 0% for all three antibiotics, while the ME was 11.4%, 5.7%, and 5.7%, respectively.

Conclusion

The resazurin-based microdilution assay established in this study showed good agreement with agar dilution method for measuring the MIC of antibiotics against Neisseria gonorrhoeae. Moreover, the sensitivity results of this method were highly reliable and could be easily obtained through naked eye observation. Nonetheless, the results of drug resistance should be treated with caution and the optimization of parameters should be continued.

Modifications to the parasitological technique of Rugai increase the diagnostic sensitivity for strongyloidiasis

Strongyloidiasis is a neglected tropical disease caused mainly by Strongyloides stercoralis, a nematode that can persist for decades in the human host with a very low parasitic burden and without specific symptoms. Hence, it is difficult to diagnose and control. Larval concentration and culture methods with fecal samples show higher sensitivity for the diagnosis of Strongyloides-infected individuals; however, these techniques are not routinely used, primarily due to the challenges associated with processing a substantial volume of fecal samples. In the current study, we comparatively evaluated the sensitivity and applicability of modifications made to the Rugai parasitological method for the diagnosis of strongyloidiasis in fecal samples of experimentally infected rats and in 68 individuals from an urban community close to Maceió, Brazil. The presence and quantity of parasite larvae in the feces were comparatively evaluated using different parasitological techniques. In the experimental model, we demonstrated that the modified Rugai technique (RMOD) allowed for significantly higher recovery of larvae than the original Rugai technique (RO). Moreover, the sediment was cleaner and easier to evaluate using optical microscopy. Compared to other parasitological techniques, such as agar-plate culture (A-PC) and spontaneous sedimentation (SS), the RMOD technique showed higher sensitivity in the detection of larvae in all infected groups and presented comparatively better performance, especially in rats with a low parasite burden. In the human population, among the 68 stool samples evaluated, Strongyloides larvae were detected in the feces of six individuals with an estimated prevalence of 8.82%. However, the performance of each parasitological method was remarkably different. SS identified Strongyloides larvae in only two individuals and A-PC in three, whereas RMOD was able to identify six infected individuals, resulting in sensitivities of 33.3%, 50%, and 100%, respectively. In conclusion, the modifications introduced to the Rugai technique resulted in improved sensitivity for the detection of Strongyloides spp. infections, especially in stool samples with a low parasite burden, in comparison with other routinely used parasitological techniques.

Development of an agar-based screening method for terbinafine, itraconazole, and amorolfine susceptibility testing of Trichophyton spp

Resistance in dermatophytes is an emerging global public health issue. We, therefore, developed an agar-based method for screening Trichophyton spp. susceptibility to terbinafine (TRB), itraconazole (ITC), and amorolfine (AMF) and validated it using molecularly characterized isolates. Α total of 40 Trichophyton spp. isolates, 28 TRB wild type (WT) (13 T. rubrum, 10 T. mentagrophytes, 5 T. interdigitale) and 12 TRB non-WT (7 T. rubrum, 5 T. indotineae) with different alterations in the squalene epoxidase (SQLE) gene, were used. The optimal test conditions (inoculum and drug concentrations, incubation time, and temperature) and stability over time were evaluated. The method was then applied for 86 WT Trichophyton spp. clinical isolates (68 T. rubrum, 7 T. interdigitale, 6 T. tonsurans, 5 T. mentagrophytes) and 4 non-WT T. indotineae. Optimal growth of drug-free controls was observed using an inoculum of 20 µL 0.5 McFarland after 5-7 days of incubation at 30°C. The optimal concentrations that prevented the growth of WT isolates were 0.016 mg/L of TRB, 1 mg/L of ITC, and 0.25 mg/L of AMF, whereas 0.125 mg/L of TRB was used for the detection of Trichophyton strong SQLE mutants (MIC ≥0.25 mg/L). The agar plates were stable up to 4 months. Inter-observer and inter-experimental agreement were 100%, and the method successfully detected TRB non-WT Trichophyton spp. strains showing 100% agreement with the reference EUCAST methodology. An agar-based method was developed for screening Trichophyton spp. in order to detect TRB non-WT weak and strong mutant isolates facilitating their detection in non-expert routine diagnostic laboratories.

Class VI G protein-coupled receptors in Aspergillus oryzae regulate sclerotia formation through GTPase-activating activity

G protein-coupled receptors (GPCRs) comprise the largest family of transmembrane receptors in eukaryotes that sense and transduce extracellular signals into cells. In Aspergillus oryzae, 16 canonical GPCR genes are identified and classified into nine classes based on the sequence similarity and proposed functions. Class VI GPCRs (AoGprK-1, AoGprK-2, and AoGprR in A. oryzae), unlike other GPCRs, feature a unique hybrid structure containing both the seven transmembrane (7-TM) and regulator of G-protein signaling (RGS) domains, which is not found in animal GPCRs. We report here that the mutants with double or triple deletion of class VI GPCR genes produced significantly increased number of sclerotia compared to the control strain when grown on agar plates. Interestingly, complementation analysis demonstrated that the expression of the RGS domain without the 7-TM domain is sufficient to restore the phenotype. In line with this, among the three Gα subunits in A. oryzae, AoGpaA, AoGpaB, and AoGanA, forced expression of GTPase-deficient mutants of either AoGpaA or AoGpaB caused an increase in the number of sclerotia formed, suggesting that RGS domains of class VI GPCRs are the negative regulators of these two GTPases. Finally, we measured the expression of velvet complex genes and sclerotia formation-related genes and found that the expression of velB was significantly increased in the multiple gene deletion mutants. Taken together, these results demonstrate that class VI GPCRs negatively regulate sclerotia formation through their GTPase-activating activity in the RGS domains. KEY POINTS: • Class VI GPCRs in A. oryzae regulate sclerotia formation in A. oryzae • RGS function of class VI GPCRs is responsible for regulation of sclerotia formation • Loss of class VI GPCRs resulted in increased expression of sclerotia-related genes.

Characterization of Poultry Gelatins Prepared by a Biotechnological Method for Targeted Changes at the Molecular Level

Chicken collagen is a promising raw material source for the production gelatins and hydrolysates. These can be prepared biotechnologically using proteolytic enzymes. By choosing the appropriate process conditions, such changes can be achieved at the molecular level of collagen, making it possible to prepare gelatins with targeted properties for advanced cosmetic, pharmaceutical, medical, or food applications. The present research aims to investigate model samples of chicken gelatins, focusing on: (i) antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis-3-etylbenzotiazolin-6-sulfonic acid (ABTS); (ii) the distribution of molecular weights via gel permeation chromatography with refractometric detection (GPC-RID); (iii) functional groups and the configuration of polypeptide chains related to molecular-level properties using Fourier transform infrared spectroscopy (FTIR); (iv) the microbiological populations on sabouraud dextrose agar (SDA), plate count agar (PCA), tryptic soy agar (TSA), and violet red bile lactose (VRBL) using the matrix-assisted laser desorption ionization (MALDI) method. Antioxidant activity towards ABTS radicals was more than 80%; activity towards DPPH radicals was more than 69%. The molecular weights of all gelatin samples showed typical α-, β-, and γ-chains. FTIR analysis confirmed that chicken gelatins all contain typical vibrational regions for collagen cleavage products, Amides A and B, and Amides I, II, and III, at characteristic wavenumbers. A microbiological analysis of the prepared samples showed no undesirable bacteria that would limit advanced applications of the prepared products. Chicken gelatins represent a promising alternative to products made from standard collagen tissues of terrestrial animals.

Silver Nanoparticle-Loaded Titanium-Based Metal-Organic Framework for Promoting Antibacterial Performance by Synergistic Chemical-Photodynamic Therapy

The abuse of antibiotics leads to an increasing emergence of drug-resistant bacteria, which not only causes a waste of medical resources but also seriously endangers people's health and life safety. Therefore, it is highly desirable to develop an efficient antibacterial strategy to reduce the reliance on traditional antibiotics. Antibacterial photodynamic therapy (aPDT) is regarded as an intriguing antimicrobial method that is less likely to generate drug resistance, but its efficiency still needs to be further improved. Herein, a robust titanium-based metal-organic framework ACM-1 was adopted to support Ag nanoparticles (NPs) to obtain Ag NPs@ACM-1 for boosting antibacterial efficiency via synergistic chemical-photodynamic therapy. Apart from the intrinsic antibacterial nature, Ag NPs largely boost ROS production and thus improve aPDT efficacy. As a consequence, Ag NPs@ACM-1 shows excellent antibacterial activity under visible light illumination, and its minimum bactericidal concentrations (MBCs) against E. coli, S. aureus, and MRSA are as low as 39.1, 39.1, and 62.5 μg mL-1, respectively. Moreover, to expand the practicability of Ag NPs@ACM-1, two (a dense and a loose) Ag NPs@ACM-1 films were readily fabricated by simply dispersing Ag NPs@ACM-1 into heated aqueous solutions of edible agar and sequentially cooling through heating or freeze-drying, respectively. Notably, these two films are mechanically flexible and exhibit excellent antibacterial activities, and their antimicrobial performances can be well retained in their recyclable and remade films. As agar is nontoxic, degradable, inexpensive, and ecosustainable, the dense and loose Ag NPs@ACM-1 films are potent to serve as recyclable and degradable antibacterial plastics and antibacterial dressings, respectively.

Activity of a foam in preventing rebound of vancomycin-resistant Enterococcus faecium-containing droplets generated from the toilet bowl

In hospital environments, droplets generated by urination within shared toilets may represent a route of dissemination for bacteria such as vancomycin-resistant Enterococcus faecium (VREfm), which contributes significantly to the burden of hospital-acquired infections. We investigated the potential activity of a foam in preventing the generation of droplets containing Enterococcus spp. during urination. A uniform layer of foam was deposited in the inner walls and at the bottom of an experimental toilet contaminated with suspensions of Enterococcus strains (including a VREfm strain). Human urination was simulated, and colonies of Enterococcus were recovered through a toilet lid where agar plates had been placed. Results showed that the foam was able to suppress production of droplets containing Enterococcus spp. generated by a liquid hitting inner toilet walls. Conversely, Enterococcus colonies were recovered in absence of foam. Moreover, the foam did not show antibacterial activity. We propose a new non-antimicrobial approach aimed at limiting transmission of multidrug-resistant bacteria, particularly in healthcare settings.

Jatrophihabitans cynanchi sp. nov., isolated from rhizosphere soil of Cynanchum wilfordii

A novel actinobacterial strain, SB3-54T was isolated from rhizosphere soil of Cynanchum wilfodill, Jaecheon, Chungcheongbuk-do, Republic of Korea. Cells of strain SB3-54T were Gram-stain-positive, aerobic, rod-shaped, and flagellated which formed pale yellow colonies on Reasoner's 2A (R2A) agar. Growth occurred at 15-30 °C (optimum 25 °C), pH 5-8 (optimum pH 7), and 0-2.5% NaCl (optimum 0%). Phylogenetic and phylogenomic analyses showed that strain SB3-54T formed a separate lineage in the genus Jatrophihabitans with Jatrophihabitans telluris N237T. Strain SB3-54T was positive for catalase activity. Genomic analysis showed that SB3-54T has plant-beneficial function contributing (referred to as PBFC) genes such as root colonization and plant protection from oxidative stress. Furthermore, genome of SB3-54T contained gene clusters related to cytokinin biosynthesis, auxin response, tryptophan biosynthesis, siderophore biosynthesis and bacterial toxin-antitoxin systems. Strain SB3-54T contained iso-C16:0 as the major fatty acid and MK-9(H4) and MK-9(H6) as the predominant quinones. The organism had meso-diaminopimelic acid as the diagnostic diamino acid in the peptidoglycan. The major polar lipids were diphosphatidylglycerol, phosphatidylinositol polymannosides, two unidentified aminoglycophospholipids and three unidentified phospholipids. Based on phylogenetic, physiological and chemotaxonomic characteristics, strain SB3-54T represents a novel species of the genus Jatrophihabitans. The type strain is SB3-54T (= KCTC 49134T = NBRC 114108T).

[Investigation of the Inhibition Effect of Acanthamoeba Cell-Free Supernatants Against Pseudomonas aeruginosa]

Free-living amoebae belonging to the genus Acanthamoeba are microorganisms that live in air, soil and aquatic environments. In humans, they cause infections such as amoebic keratitis, graulamotous amoebic encephalitis that are difficult to treat and can be fatal. In addition, it is known that they contribute to the replication of bacteria and increase their pathogenicity by being a host for various bacteria. However, information on its inhibitory properties against bacteria and its production of antimicrobial agents is very limited. In this context, in this study, it was aimed to investigate whether cell-free supernatants of Acanthamoeba strains have antibacterial effects against Pseudomonas aeruginosa isolates. Four different Acanthamoeba strains (A10, A13, A14, U.GÖL) isolated from aquatic environments in our country were selected and used in the study, P.aeruginosa isolates (PA2, PA3, PA4, PA5) were selected from clinical strains belonging to patients in our country. Acanthamoeba castellanii ATCC 50373 and P.aeruginosa ATCC 27853 were used as standard strains. P.aeruginosa isolates were grown on nutrient agar at 37 °C and Acanthamoeba strains were grown on E.coli spread non-nutrient agar at 30 °C under aerobic conditions. Pepton yeast extract glucose (PYG) medium supplemented with penicillin and streptomycin was used to obtain axenic cultures of Acanthamoeba strains. After the centrifugation of axenic cultures at 3000 rpm for five minutes, Acanthamoeba-cell-free supernatants were obtained by filtering the supernatant part through a sterile filter with a pore diameter of 0.22 µm. The antibacterial activities of these supernatants against P.aeruginosa isolates were determined using the colony counting method. Analysis of each Acanthamoeba-cell-free supernatants was performed according to the GC-MS method. Acanthamoeba-cell-free supernatants were found to have varying degrees of inhibitory effects (3.9-91.5%) against tested P.aeruginosa isolates. It was determined that the cell-free supernatant of A.castellanii ATCC 50373 strain showed the highest antibacterial effect (91.5%) against PA5 isolate. A14 strain showed similar inhibitory effects (89.4%) against the same Pseudomonas isolate. The average inhibitory effect of most of the Acanthamoeba strains of our country was found to be higher than that of the reference strain A.castellanii ATCC 50492. It is thought that the compounds responsible for the anti-Pseudomonas activity of the tested Acanthamoeba strains may be fructose, phosphoric acid, galactose, N-Acetylphenylalanine and glucopyranose determined as major compounds. This is the first study showing the anti-Pseudomonas activity of microorganisms of the genus Acanthamoeba living in the waters of our country. Acanthamoeba, which is widely found in nature, appears to be a good source for new antimicrobial agents.

Isolation and detection of bacterial species on mitis salivarius bacitracin agar from the plaque samples of caries active children

BACKGROUND

In cariology studies, mitis-salivarius-bacitracin (MSB) agar has been commonly considered as the selective medium for Streptococcusmutans growth. The present study was the part of a funded project (a noninferiority randomized controlled trial) which compared the efficacy of a plant extract-based mouth rinse with that of a fluoride mouth rinse on the S.mutans counts of the children.

AIM

This study aimed to identify the frequency of detection of S.mutans and nonstreptococcal bacterial species from the dental plaque of caries active children using a combined technique of anaerobic culture and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry.

SETTINGS AND METHODS

Caries-active children (8-12 years old) were enrolled from a pediatric dental outpatient department at a tertiary care hospital. From each participant, dental plaque samples were collected from carious surfaces under sterilized conditions and then subjected to anaerobic culture. After 48 h of incubation, the bacterial colonies were isolated by sub-culture and identified by the MALDI-TOF.

RESULTS

In all, 13 different bacterial species were isolated from the MSB agar medium. Other than S.mutans species, colonies of bacterial species such as Veillonelladispar,Streptococcusanginosus, Veillonellaparvula, and Streptococcusgordonii were also frequently observed from the medium.

CONCLUSIONS

The study concluded that several bacterial strains, both streptococcal and nonstreptococcal, could be isolated from the MSB agar medium; hence, this medium should no longer be considered selective medium for the culture of S.mutans in clinical and epidemiological studies.

Combined use of 3D printing and mixed reality technology for neurosurgical training: getting ready for brain surgery

OBJECTIVE

Learning surgical skills is an essential part of neurosurgical training. Ideally, these skills are acquired to a sufficient extent in an ex vivo setting. The authors previously described an in vitro brain tumor model, consisting of a cadaveric animal brain injected with fluorescent agar-agar, for acquiring a wide range of basic neuro-oncological skills. This model focused on haptic skills such as safe tissue ablation technique and the training of fluorescence-based resection. As important didactical technologies such as mixed reality and 3D printing become more readily available, the authors developed a readily available training model that integrates the haptic aspects into a mixed reality setup.

METHODS

The anatomical structures of a brain tumor patient were segmented from medical imaging data to create a digital twin of the case. Bony structures were 3D printed and combined with the in vitro brain tumor model. The segmented structures were visualized in mixed reality headsets, and the congruence of the printed and the virtual objects allowed them to be spatially superimposed. In this way, users of the system were able to train on the entire treatment process from surgery planning to instrument preparation and execution of the surgery.

RESULTS

Mixed reality visualization in the joint model facilitated model (patient) positioning as well as craniotomy and the extent of resection planning respecting case-dependent specifications. The advanced physical model allowed brain tumor surgery training including skin incision; craniotomy; dural opening; fluorescence-guided tumor resection; and dura, bone, and skin closure.

CONCLUSIONS

Combining mixed reality visualization with the corresponding 3D printed physical hands-on model allowed advanced training of sequential brain tumor resection skills. Three-dimensional printing technology facilitates the production of a precise, reproducible, and worldwide accessible brain tumor surgery model. The described model for brain tumor resection advanced regarding important aspects of skills training for neurosurgical residents (e.g., locating the lesion, head position planning, skull trepanation, dura opening, tissue ablation techniques, fluorescence-guided resection, and closure). Mixed reality enriches the model with important structures that are difficult to model (e.g., vessels and fiber tracts) and advanced interaction concepts (e.g., craniotomy simulations). Finally, this concept demonstrates a bridging technology toward intraoperative application of mixed reality.

Research Note: Preliminary results, first detection of Enterococcus cecorum from environmental samples by streaking on X-Gluc containing selective media

The isolation of cultivable E. cecorum from the environment of poultry houses remains a challenge. Environmental samples (dust wipes, equipment swabs, pooled feces) and samples from culled bird vertebras were collected from an infected broiler flock on d 37 posthatching. To isolate the bacterium from the cultivable microbiota, suspensions from the environmental samples were streaked onto a blood agar base medium supplemented with 5-bromo-4-chloro-3-indolyl-beta-D-glucuronic acid cyclohexylammonium salt (X-Gluc), colistin sulfate, and nalidixin. The chromogenic reaction facilitated the isolation of E. cecorum from contaminated surfaces and pooled feces. Isolates from both the environment and vertebras were confirmed using MALDI-TOF and PCR analysis. Colony appearance and antimicrobial susceptibility tests revealed no phenotypic differences among the isolates. It remained unclear whether the isolates originated from the same clone. However, the principle of isolating the pathogen by streaking on a chromogenic agar may motivate researchers to investigate the transmission routes of infectious isolates, potentially leading to the optimization of biosecurity measures.

Use of a chromogenic medium with and without selective enrichment to screen for carbapenemase-producing Enterobacterales (CPE) from canine and feline fecal specimens during an outbreak of NDM-5-producing Escherichia coli

Carbapenemase-producing Enterobacterales (CPE) are one of the most urgent threats to human healthcare globally. Descriptions of CPE outbreaks in veterinary hospitals suggest the need for screening strategies for CPE from companion animals. Our aim was to optimize a chromogenic agar method with and without selective enrichment to isolate CPE from companion animal feces in an ongoing outbreak of New Delhi metallo-β-lactamse-5 Escherichia coli. A limit of detection (LOD) assay for spiked canine and feline feces was performed for both methods using a carbapenamase-producing E. coli (24213-18); the LOD (1.5 × 103 cfu/g of feces) was equivalent to that reported for human fecal specimens. We screened 1,247 companion animal fecal specimens for carriage of CPE by 1) direct plating to chromogenic agar and 2) plating to chromogenic agar following selective enrichment. Twenty-one specimens were positive for CPE by both direct culture and enrichment culture. No specimens were positive with selective enrichment and negative by direct culture. A selective enrichment step did not result in any increased recovery of CPE from companion animals, which suggests that enrichment broth may not be necessary for outbreak surveillance testing. It is important to continue to validate methods for the detection of CPE in companion animals as outbreaks become more common in veterinary facilities.

Micropropagation of Encyclia cordigera (Kunth) Dressler in Ebb-and-Flow Bioreactor

The use of new technologies for micropropagation such as temporary immersion systems (TISs) is important, because it reduces costs by 40% lowering labor, agar and containers. TISs are containers designed for large-scale, semiautomatic production of plants in a liquid medium, which has been used in propagation of commercial orchids. This tool has high potential for application in micropropagation of medicinal and endangered orchids for conservation and commercial purposes. In this chapter, we describe a detailed protocol for propagation and development of Encyclia cordigera to be used in research projects for small-scale production. This protocol comprises all steps from explant preparation to the establishment orchids plantlets.

Ethambutol inhibited the growth of acid-fast bacteria and enhanced the detection of Legionella in environmental water samples

The growth of acid-fast bacteria often hinders the detection of Legionella in water samples on agar plates by the plate culture method. We studied whether anti-tubercular agents inhibit acid-fast bacteria growth on agar plates. First, the antimicrobial activities of isoniazid, ethionamide, and ethambutol were evaluated against Mycobacterium and Legionella. We found that ethambutol at ≥ 100 μg/mL completely inhibited Mycobacterium growth, but ethambutol at 1,000 μg/mL did not inhibit Legionella growth. Next, the effect of ethambutol dissolved in acid buffer was examined. Cell suspensions of L. pneumophila and Mycobacterium spp. were mixed, and ethambutol-acid buffer was added. After 5 min, mixtures were inoculated on GVPC agar plates and incubated at 36℃ for 6 d. We found that ethambutol inhibited Mycobacterium growth on agar plates, but the Legionella colonies recovered. The effect of ethambutol was also significant in the evaluation using bathwaters. Comparing 1,302 bathwaters, the addition of ethambutol reduced the detection rate of acid-fast bacteria from 30.6% to 0% and increased the detection rate of Legionella from 7.1% to 7.5%. Ethambutol, which selectively inhibited acid-fast bacteria growth, enhanced the detection of Legionella on agar plates and will contribute to improving the accuracy of Legionella testing by the plate culture method.

Antimicrobial Susceptibility Patterns of Bacterial Isolates from Blood Culture of Pediatric Patients with Suspected Sepsis at a Tertiary Care Hospital in Mymensingh, Bangladesh

Sepsis is a serious, life-threatening condition, occurring when an infectious agent invades the body, resulting in systemic inflammatory response syndrome (SIRS). Neonates and children are among the most vulnerable population groups of developing sepsis because of their weak immune barrier. Despite major advances in prevention, diagnosis and treatment of bacterial infections, invasive infections followed by sepsis remain one of the leading causes of childhood mortality. The aim of this study was to identify bacterial agents and antimicrobial resistance patterns of aerobic bacteria among children suspected of having sepsis. This cross-sectional descriptive type of observational study was conducted in the Department of Microbiology, Mymensingh Medical College, Bangladesh from March 2021 to February 2022. Blood samples were collected from pediatric patients, suspected of having sepsis referred from inpatient facility of department of Neonatology and Pediatrics, Mymensingh Medical College Hospital (MMCH). Blood samples were inoculated into BacT/ALERT PF Plus bottles followed by sub-culture of positive samples in blood agar, MacConkey agar and chocolate agar plates. Isolated bacteria were identified by routine biochemical tests. Antimicrobial resistance pattern of all isolated bacteria was seen by disk diffusion method. MIC of vancomycin by agar dilution method was determined for isolated S. aureus and Coagulase negative Staphylococci (CoNS). The prevalence of pediatric sepsis was 31.82% with highest isolation rate 35.55% among neonates. The isolation rate of gram-positive bacteria was 62.50% where S. aureus was the most common isolate 32.15% followed by CoNS 30.36%. Out of 21 gram-negative bacteria, Pseudomonas spp. was the most frequent isolate 7(33.33%), all of which were resistant to cefuroxime, ceftriaxone and ceftazidime along with all klebsiella and Acinetobacter isolates. Out of 18 S. aureus isolates, 94.44%, 88.89% and 66.67% were resistant to Azithromycin, Penicillin-G and Ciprofloxacin respectively. The MIC of Vancomycin by agar dilution method was observed <2μg/ml against all isolated S. aureus and CoNS. All the Gram-positive isolates were sensitive to Linezolid and Vancomycin. Early detection of bacteria followed by antimicrobial susceptibility test can help by selection of appropriate antibiotic and prevent spread of infection.

Fly clock, my clock, and lamin B receptor

In the fruit fly Drosophila melanogaster, circadian rhythm was disrupted when the inner nuclear membrane protein lamin B receptor (LBR) was depleted from its clock neurons (Proc. Natl. Acad. Sci. USA 118, e2019756118. 2021; https://doi.org/10. 1073/pnas.2019756118 and Research 6, 0139, 2023; https://doi.org/10.34133/research.0139). Ordinarily, the clock proteinPERIOD (PER) forms foci close to the inner nuclear membrane in the circadian clock's repression phase. The size, number, and location of foci near the nuclear membrane oscillate with a 24-h rhythm. When LBR was absent the foci did not form. The PER foci bring per and other clock genes close to the nuclear envelope, where their transcription is silenced. Then, in the circadian clock's activation phase, the PER protein gradually gets degraded and the foci disappear. The clock genes, including per, relocate to the nucleus interior where they resume transcription. Rhythmic re-positioning of clock genes between nucleus periphery and interior, correlates with their repression and activation in the circadian cycle. Absence of LBR disrupted this rhythm. Phosphorylation of PER promoted the formation of foci whereas dephosphorylation by protein phosphatase 2A causedthem to disappear. LBR promoted focus formation by destabilizing the catalytic subunit of protein phosphatase 2A. The lbr gene is no stranger to this journal. The first hint that vertebrate LBR is also a sterol biosynthesis enzyme, specifically, a sterol C14 reductase, was reported here (J. Genet. 73, 33-41, 1994; https://www.ias.ac.in/article/fulltext/jgen/073/01/0033-0041). Mutations in the human Lbr gene cause a range of phenotypes--from the relatively benign Pelger-Huet anomaly to the perinatally lethal Greenberg skeletal dysplasia.Drosophila, like all insects, is a sterol auxotroph. The fly orthologue of vertebrate lbr genes encodes a protein (dLBR) that shares several properties with vertebrate LBR proteins, with one notable exception. While human LBR complemented theyeast Saccharomyces cerevisiae erg24 mutant which lacks sterol C14 reductase activity, dLBR did not (J. Cell. Sci. 117, 2015-28, 2004; https://doi.org/10.1242/jcs.01052). Despite not possessing sterol reductase activity, dLBR retains significant sequence homology with vertebrate LBRs which have this activity. An undergraduate summer trainee in my laboratory obtained early (unpublished) evidence that dLBR lost sterol reductase activity during evolution. She transferred adult drosophila flies to vials containing a medium made of agar, dextrose, and dried and powdered mycelium of the filamentous fungus Neurospora crassa. On medium made with wild-type mycelium, theflies mated, laid eggs, hatched larvae, and developed pupae which eclosed progeny adult flies. The life cycle was no different than on 'regular' fly food composed of agar, dextrose and yeast extract. However, on a medium made with mycelium from a sterol C14 reductase null mutant, the flies laid eggs which hatched and released larvae, but the larvae failed to pupate, and no adult progeny flies emerged. This was because the fly lacks a sterol C14 reductase. The wild-type sterol, ergosterol, is a precursor of the steroid hormone ecdysone needed for molting and metamorphosis. Can expression of vertebrate LBR in dLBR-depleted fly clock neurons restore circadian rhythm? Can expression of vertebrate LBR enable flies to complete their life cycle on mutant Neurospora medium? Does LBR regulate the vertebrate clock in a like manner? If yes, then is the sterol reductase activity dispensable in this role? These are some questions that came to my mind on a recent morning walk. The walk itself was a much-cherished outcome of my circadian clock.

Metals recovery from polymetallic sulfide tailings by bioleaching functional bacteria isolated with the improved 9K agar: Comparison between one-step and two-step processes

Due to the characteristics of simple process, environmental friendliness and low operating costs, biometallurgy has become a popular technology for metals recovering from low-grade ores and tailings. In order to enhance the efficiency of bioleaching functional bacteria acquisition, the 9K agar was optimized by adjusting the ratio of two solutions to achieve better and faster solidification for the functional bacteria growth and isolation. By using the improved 9K agar, six functional stains within genera of Acidithiobacillus ferriphilus, A. ferrooxidans and Leptospirillum ferrooxidans were isolated from the enrichment of acid mine drainage. After the Fe2+ oxidation ability evaluation, three strains of WT1-1, XT2-2, and YT3-1 within the three genera were selected and employed as the individual inoculum for the bioleaching from polymetallic sulfide tailings. Eventually, a maximum leaching efficiency of 58.37% Cu, 53.14% Al, 80.09% Mg, and 76.95% Zn were observed by A. ferriphilus WT1-1 after 28 d. To further improve the bioleaching efficiency, the three strains were mixed proportionally as the inoculum in both one-step and two-step bioleaching processes. Comparing to the pure cultures, the leaching efficiencies of Cu and Mg were significantly enhanced in both one- and two-steps, while no significant change in Zn. By comparing the one- and two-step processes, leaching efficiencies of Al, Mg, and Zn were higher in the one-step process, whereas Cu was observed to be higher in the two-step process. Therefore, the selection on leaching process of one or two steps should be determined based on tailings composition and target metals.

Isolation and investigation of external reproduction tract mycoflora in healthy male cats

BACKGROUND

Various infectious agents can infect the male reproductive system.

OBJECTIVES

The aims of this study were to provide current data on fungal and yeast flora of the external organs of reproductive system of male short hair cats including penis and prepuce.

METHODS

In total 28 samples were taken from external genital system of male stray cats using sterilised cotton swabs. Samples were taken based on the absence of any reproductive complications using physical examinations. The samples were transferred to sterilised Stuart transport media and were then incubated in the Sabouraud dextrose agar with chloramphenicol at 32°C for 48 h. The identification of fungi and yeasts was confirmed by germ tube formation test, CHROM agar, urease testing and Corn meal agar medium with Tween 80.

RESULTS

Fungal agents were isolated from 7 (25%) out of 28 male stray cats. Fungal isolates were obtained from the penis and prepuce of 4 (36%) and 7 (100%) male cats, respectively. The most commonly recovered species samples were Candida krusei (3.75%) and Penicillum spp. (6.86%) from the penis and prepuce of the cats, respectively. The external organs of male reproduction of cats were infected with 2-4 different fungal agents. Only 5 (45%) cats were infected with one fungus; however, in 6 (55%) cats, mixed fungal infections were isolated. Cats 3-4 years old had the highest fungal contamination in the prepuce region (4/7), while the penis at this age had the least contamination (1/4).

CONCLUSIONS

It is concluded that the external reproduction organs of male cats could be infected by different fungal agents.

Quantitative Determination of Antibacterial Activity During Bacterial Coculture

Antibacterial activity assays are an important tool in the assessment of the ability of one bacterium to kill or inhibit the growth of another, for example, during the study of the Type VI secretion system (T6SS) and the antibacterial toxins it secretes. The method we describe here can detect the ability of a bacterial strain to kill or inhibit other bacterial cells in a contact-dependent manner when cocultured on an agar surface. It is particularly useful since it enumerates the recovery of viable target cells and thus enables quantification of the antibacterial activity. We provide a detailed description of how to measure the T6SS-dependent antibacterial activity of a bacterium such as Serratia marcescens against a competitor prokaryotic organism, Escherichia coli, and describe possible variations in the method to allow adaptation to other attacker and target organisms.

Ocular antibacterial chitosan-maleic acid hydrogels: In vitro and in vivo studies for a promising approach with enhanced mucoadhesion

The aim was to design and evaluate a chitosan-based conjugate providing high mucoadhesiveness and antibacterial activity for ocular infections treatment. Chitosan was conjugated with maleic acid via amide bond formation and infrared spectroscopy. Furthermore, 2,4,6-Trinitrobenzene sulfonic acid (TNBS) allowed characterization and quantification of conjugated groups, respectively. Biocompatibility was tested via hemolysis assay and Hen's Egg-Chorioallantoic membrane test. Characterization of the pH and osmolarity of hydrogels was followed by mucoadhesion assessment utilizing rheology. In addition, antibacterial studies were carried out towards Escherichia coli by broth microdilution test and agar-disk diffusion assay. In vivo studies were carried out following the already established Draize test and determining pharmacokinetic profile of dexamethasone in aqueous humour. The conjugate exhibited a degree of modification of 50.05 % and no toxicity or irritability. Moreover, mucoadhesive properties were enhanced in 2.68-fold and 1.81-fold for elastic and viscous modulus, respectively. Furthermore, rheological synergism revealed the presence of a gel-like structure. Additionally, broth microdilution and agar disk diffusion studies exhibited enhancement in antibacterial activity. Finally, in vivo studies manifested that hydrogels were highly tolerated, evidencing promising characteristics of the developed conjugate. The conjugate presented promising antimicrobial, long lasting mucoadhesive features and highly improved pharmacokinetics, leading to a revolutionizing approach in the treatment of ocular bacterial infections.

Talaromyces mellisjaponici sp. nov., a xerophilic species isolated from honey in Japan

Five isolates of a xerophilic Talaromyces species were obtained from honey in Japan. Molecular phylogenetic analysis based on a combined dataset for four regions (rRNA internal transcribed spacer, β-tubulin, calmodulin and RNA polymerase II second largest subunit) revealed that the strains formed an independent clade in section Trachyspermi, which is sister to Talaromyces affinitatimellis, Talaromyces basipetosporus and Talaromyces speluncarum. The strains and their relatives have different growth on creatine agar, yeast extract sucrose agar and dichloran 18 % glycerol agar, different branching patterns (mostly monoverticillate or biverticillate, less frequently divaricate or terverticillate), and different sizes and surface structures of conidia. Xerotolerance tests were also conducted using media adjusted to five different sucrose concentrations (0, 20, 40, 60 and 80 %). The colony diameters of the strains were larger than those of T. affinitatimellis, T. basipetosporus and T. speluncarum at each sucrose concentration. Altogether, the obtained morphological, molecular and physiological data allowed the proposal of Talaromyces mellisjaponici sp. nov. for this novel species, with NBRC 116048T as the type strain.

[A New Case of Fournier's Gangrene Caused by Actinotignum schaalii]

Actinotignum schaalii (formerly known as Actinobaculum schaalii) is an anaerobic or facultative anaerobic gram-positive bacillus that can be found commensally in the urogenital region. It can be overlooked because it grows slowly and is difficult to identify with classical microbiology laboratory techniques. Colonies become visible after 48-72 hours of incubation on blood agar in anaerobic or CO₂-rich media. While it typically causes urinary tract infection in older individuals, cases of bacteremia, vertebral osteomyelitis, endocarditis and cellulitis have been reported. Fournier's gangrene caused by A.schaalii has been reported very rarely so far. Fournier's gangrene has been defined as necrotizing fasciitis of the external genitalia, perineal and perianal region. Diabetes, immunosuppression, peripheral vascular disease, urethral anomalies, chronic alcoholism and smoking are important predisposing factors. In addition, approximately 25% of the cases have no known or identifiable etiology. The bacteria causing the infection may originate from skin, urogenital or intestinal microbiota. In this case report, a new case of Fournier's gangrene caused by A.schaalii was presented. A 65-year-old male patient admitted to the emergency department with the complaints of pain, swelling, redness in the left testis and also nausea, vomiting and chills that started three days ago. Physical examination revealed increased diameter of the scrotum, intense hyperemia of the skin and foci of necrosis. It was learned that the patient had no known chronic disease other than benign prostatic hyperplasia. The patient reported smoking of 25 packs of cigarettes per year. Routine laboratory tests revealed leukocyte= 32.41 x 109/L, neutrophil= 89.9%, procalcitonin= 1.62 ug/L, CRP= 265.07 mg/L and the patient was operated with the diagnosis of Fournier's gangrene. Gram staining of the abscess specimen obtained during the operation showed gram-positive bacilli both inside and outside the leukocytes. After 24 hours, grampositive bacilli were detected in the Gram staining of thin, transparent/gray colonies grown on 5% sheep blood and chocolate agar. The isolate was identified as A.schaalii by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) VITEK® MS (bioMérieux, France) microbial identification system. VITEK®2 ID ANC (bioMérieux, France) bacterial identification card was also used for comparison but the bacteria could be identified. As a result of the sequence analysis performed for confirmation, it was shown to be 100% homologous with Actinobaculum schaalii (GenBank accession no: FJ711193.1). For susceptibility tests, 5% sheep blood Schaedler agar was used and incubated in anaerobic environment. According to the minimal inhibitory concentration (MIC) results evaluated after 48 hours, penicillin was found to be 0.032 mg/L, clindamycin 0.125 mg/L, ciprofloxacin 0.19 mg/L, ceftazidime 4 mg/L, and amoxicillin 0.19 mg/L. The primary cause that initiated the infection in the case could not be identified, but it was thought that the presence of prostatic hyperplasia and smoking history may have contributed to the occurence or the progress of the disease. It is noteworthy that the ciprofloxacin MIC result was quite low compared to other studies. In addition, this study revealed the value of MALDI-TOF MS based methods in identification. In conclusion, it is thought that a significant proportion of A.schaalii infections may be overlooked due to the difficulty in growth and identification. Increasing the diagnostic power of clinical microbiology laboratories for poorly identified bacteria and renewing the databases of commercial identification systems are important for the early and accurate diagnosis and treatment of serious infections that may occur with such agents.

Development of an Electrical Impedance Tomography Coupled Surgical Stapler for Tissue Characterization

OBJECTIVE

This study explores the feasibility of coupling Electrical Impedance Tomography (EIT) to a standard-of-care laparoscopic surgical stapler, stapler+EIT, with the long-term goal of enabling intraoperative tissue differentiation for tumor margin detection.

METHODS

Two custom printed-circuit-board-based electrode arrays with 60 and 8 electrodes, respectively, matching the stapler geometry, served as the jaws of an electrode-integrated surrogate stapler+EIT device. The device was evaluated through a series of simulations and bench-top imaging experiments of agar-gel phantoms and bovine tissue samples to evaluate the technique and determine optimal imaging parameters.

RESULTS

Electrodes localized to only one jaw (the 60-electrode side) of the stapler outperformed a dual-jaw distribution of electrodes. Using this one-sided electrode array, reconstructions achieved an Area-Under-the-Curve (AUC) ≥ 0.94 for inclusions with conductivity contrasts of ≥30% for any size considered on measured agar-gel tests, and an AUC of 0.80 for bovine tissue samples.

CONCLUSION

A stapler+EIT algorithm has been tuned and evaluated on challenging phantom tests and demonstrated to produce accurate reconstructions.

SIGNIFICANCE

This work is an important step in the development of a surgical stapler+EIT technique for margin assessment.

Enumeration of Bacteriophages by Plaque Assay

Enumeration of bacteriophages by plaque assay requires the mixing of host-specific bacteria with a lytic bacteriophage of interest in a soft agar overlay (top agar) to prevent the spread of viral infection in the medium; the mixture is then spread on a solid bottom agar. An infection of a single lytic phage particle with a bacterium results in the lysis of the host bacterium and the release of new phage progeny. The new phage progeny released from each bacterium will infect/lyse neighboring bacteria to form a "plaque," which is a clear visible area (that can be counted) with the naked eye. If phages are not present in the mixture, the host bacterium will form a "lawn" in the soft agar overlay and grow to a stationary phase.

MXene/zinc ion embedded agar/sodium alginate hydrogel for rapid and efficient sterilization with photothermal and chemical synergetic therapy

Bacterial infections can significantly impair wound healing. Therefore, it is essential to develop wound dressings with high antimicrobial activity. Hydrogels are often used as wound dressings due to their excellent physicochemical properties. Herein, by cross linking sodium alginate (SA), agar (AG) with Ti3C2Tx MXene and Zinc ions (Zn2+), a biosafe composite hydrogel (MSG-Zn2+) was developed for fast and efficient sterilization treatment. The excellent photothermal properties of Ti3C2Tx MXene and the chemical antimicrobial activity of Zn2+ enable synergistic photothermal therapy (PTT)/chemical therapy in NIR biowindow with reduced power density and improved antimicrobial efficiency. More importantly, the incorporation of Zn2+ can enhance the effective contact between the hydrogel and bacteria, benefiting both photothermal and chemical antibacteria. In vitro antibacterial experiments showed that MSG-Zn2+ has a broad-spectrum antibacterial effect against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). Cellular experiments showed that the hydrogel had excellent biocompatibility and the released Zn2+ stimulated cell migration. In addition, the prepared MSG-Zn2+ hydrogel has other advantages such as hydrophilic, high swelling, simple and low cost preparation, which meets the requirements of an economical wound dressing. This proposed work shows that this composite hydrogel MSG-Zn2+ has great potential for practical antimicrobial wound dressing applications.

[Conventional paraffin embedding technique and double-embedding technique for minute oral biopsies and delicate pulp tissue - a comparative study]

BACKGROUND

Among oral biopsies, small incisional tissues, have to be preserved all through the processing and embedding to ensure optimal visualization of all the mucosal layers without compromise. Optimal tissue orientation is the most critical step in tissue processing for demonstration of definitive morphology in the sections, which is often more challenging in cases of minute/small or thinner sections using routine paraffin techniques to evaluate accurate diagnosis. Some modification is needed to handle these samples to get a better result. Double embedding technique with some modification has been widely used for small/ thin/ multiple biopsies and gives excellent results in many other fields like general pathology and biotechnology. The double embedding technique though produced excellent and significant results in mucosal biopsies yet, it is of minimal interest among oral pathologists. To best of our knowledge, this is the first study to use double embedding technique for pulp tissues.

OBJECTIVE

The present study was aimed to evaluate and compare the ease of embedding and sectioning sections using Agar-Paraffin double embedding technique for small oral mucosal biopsies and thin pulp tissues.

MATERIAL AND METHODS

A total of 40 oral tissue samples categorized into two groups were taken for the present study. Group I included 20 small oral mucosal biopsy samples of size ranging from 0.2 to 0.5 cm and Group II included 20 pulp tissues obtained from freshly extracted non carious tooth. 10 blocks were prepared by routine paraffin method and 10 blocks were prepared by modified double embedding method for each group. Scores were given by comparing all the criteria with that of the routine paraffin technique. Chi-square test was used for statistical analysis.

RESULTS

The average ease score for the Agar-Paraffin double embedded small/minute biopsies showed better scores than the pulp tissue with that of the routine technique. However, no statistically significant difference was seen among embedding and sectioning sections between the two groups.

CONCLUSION

Modified double embedding method is simple and reliable alternative technique that helps in better orientation, processing and sectioning especially for oral small or thin biopsies and delicate pulp tissues.

Isolation and characterization of tannin-degrading bacteria from the rumen of wild Hokkaido sika deer (Cervus nippon yezoensis)

We isolated tannin-degrading bacteria from the rumen of wild Hokkaido sika deer and characterized their phylogeny and tannase activity in relation to sample sources. The condensed tannin level was higher in all deer rumen samples (n = 20) than in forage-fed cattle rumen samples (n = 6), whereas no hydrolyzable tannins were detected in any of the rumen samples. Rumen bacteria were enumerated on nonselective brain heart infusion (BHI) agar medium and then transferred onto tannic acid-containing BHI agar plates to screen for bacteria only showing growth (tannin-resistant bacteria) and those showing both growth and a clear zone (tannin-degrading bacteria). Summer samples provided only tannin-resistant bacteria, none of which showed tannin-degrading activity. Although winter samples also provided tannin-resistant bacteria, most isolates exhibited tannin-degrading activity. A total of 70 isolates exhibiting tannin-degrading activity were classified as Streptococcus bovis group based on 16S rRNA gene sequencing and further classified into two groups, either group A or group B. Group A consisted of isolates showing weak tannase activity, whereas group B included a majority of the isolates exhibiting high tannase activity. These results suggest that wild Hokkaido sika deer develop tannin-degrading Streptococcus in the rumen during winter, which allows access to woody food materials rich in tannins.

Media-milled agar particles as a novel emulsifier for food Pickering emulsion

Pickering emulsions was successfully fabricated using ball-milled agar particles with sizes and sulfate content around 7 μm and 0.62 %, respectively. These particles were obtained through a simple media-milling process using agar powders initially sized at 120 μm. The lamellated agar is aggregated into a mass after the milling process. The surface charge and hydrophobicity of the ball-milled agar particles were characterized through zeta potential and contact angle measurements, respectively. The droplet size of Pickering emulsions was related to oil fraction and particle concentration, ranging from approximately 45 μm to 80 μm. Ball-milled agar stabilized emulsions were sensitive to pH and salt conditions. The results of confocal laser scanning microscopy and cryo-SEM showed that at low particle concentrations and oil fractions, ball-milled agar stabilized the emulsions by dispersing particles on the surface of the oil droplets through electrostatic repulsion. Conversely, ball-milled agar stabilized the emulsions under high particle concentrations and oil fractions by forming a gel network structure to bind the oil droplets. In this research, this developed method provides the basis for the high-value application of agar and a new idea for preparing stable food-grade Pickering emulsion-based functional foods using raw-food material without surface wettability.

Preparation of agar functionalized graphene oxide-immobilized copper ferrite aerogel for dye degradation via dark-Fenton oxidative process

Dye and textile industries are one of the main causes of water pollution and put the environment and health of society at risk. Developing new materials to decontaminate industrial waste effluents containing dyes as pollutants is challenging due to numerous issues, including tailoring recyclable and biodegradable agents. This study focuses on applying an advanced oxidation process, electro-Fenton for the treatment of dye-containing wastewater using agar-functionalized graphene oxide-immobilized copper ferrite aerogel. The objective is therefore to determine the optimal conditions for the degradation of model pollutants methylene blue (MB). MB was oxidized and degraded through the dark-Fenton process using Agar@GO-CuFe2O4 as a new biobased catalyst. The effect of the operating parameters was then evaluated to determine the optimal conditions. The degradation process was screened for different initial concentrations of dye solution between 10 and 150 mg/l, a volume range of H2O2 between 0.5 and 2.5 ml, and different pH from 2 to 7. The results show that 99.89 % of the MB with the initial concentration of 150 ppm was degraded by 20 mg of the catalyst and 2 ml of H2O2 (30 % W/W) at 40 °C and pH = 6. Pseudo-second-order kinetics satisfactorily describes the experimental data. SYNOPSIS: The prepared catalyst can be applied to oxidize industrial effluents before they are released into the environment.

Ketoconazole-loading strategy to improve antifungal activity and overcome cytotoxicity on human renal proximal tubular epithelial cells

Ketoconazole (KTZ), an antifungal agent used to treat localized or systemic fungal infections by inhibiting ergosterol synthesis, exhibits restricted efficacy within eukaryotic cells owing to its elevated toxicity and limited solubility in water. This study aims to improve the biological activity and overcome cytotoxic effects in the renal system of the hydrophobic KTZ by incorporating it into poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) utilizing biomaterial nano-engineering techniques. KTZ-loaded PLGA NPs (KTZ-NPs) were prepared by single emulsion solvent evaporation method and characterized by using dynamic light scattering (DLS), electrophoretic light scattering (ELS), Fourier transform-infrared (FT-IR) spectroscopy and scanning light microscopy (SEM). Particle size and zeta potential of KTZ-NPs were determined as 182.0 ± 3.27 nm and -27.4 ± 0.56 mV, respectively. Antifungal activity was analyzed with the time-kill and top agar dilution methods onCandida albicans(C. albicans) andAspergillus flavus(A. flavus). Both KTZ and KTZ-NPs caused a significant decrease inA. flavuscell growth; however, the same effect was only observed in time-killing analysis onC. albicans, indicating a methodological difference in the antifungal analysis. According to the top agar method, the MIC value of KTZ-NPs againstA. flavuswas 9.1μg ml-1, while the minimum inhibition concentration (MIC) value of KTZ was 18.2μg ml-1. The twofold increased antifungal activity indicates that nanoparticular drug delivery systems enhance the water solubility of hydrophobic drugs. In addition, KTZ-NPs were not cytotoxic on human renal proximal tubular epithelial cells (HRPTEpCs) at fungistatic concentration, thus reducing fungal colonization without cytotoxic on renal excretion system cells.

Fe(III) cross-linked cellulose-agar hydrogel beads for efficient phosphate removal from aqueous solutions

Fe(III) cross-linked cellulose agar beads (Fe-CLCAB) were synthesized by sol-gel method and employed as adsorbents for the removal of phosphate ions from aqueous medium. The synthesized Fe-CLCAB was characterized by its swelling property, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and UV-Vis absorption spectroscopic analysis. Batch adsorption studies were carried out to find out the optimum conditions of phosphate uptake. The adsorption process was found to fit both Langmuir and Freundlich adsorption isotherm model, pseudo-second-order kinetic model, and Elovich kinetic model. Ninety-four percent phosphate adsorption was achieved with 500 beads at pH 5. Maximum monolayer adsorption capacity was 73.13 mg/g. A two-step elution process using sodium chloride solution was suitable for complete desorption of phosphate from Fe-CLCAB. Six cyclic adsorption-desorption tests were conducted using a 0.1 M NaCl solution as desorbing agent. The removal efficiency of regenerated Fe-CLCAB was 42% of its original value after six cycles, which validates good stability and effectiveness of the prepared hydrogel beads. Ion exchange plays a vital role during adsorption/desorption of phosphate.

Microbiological evaluation of conjunctival anopthalmic flora after using digital 3D-printed ocular prosthesis compared to conventional one: a randomized clinical trial

BACKGROUND

This study aims to assess the influence of using 3D-printed acrylic resin versus conventional Poly-methyl methacrylate (PMMA) for fabricating ocular prostheses on the biofilm and microbial flora of anophthalmic socket.

METHODS

A randomized controlled trial was designed as a parallel group study. Participants were allocated randomly into two groups: the control group, which received conventionally fabricated ocular prostheses (CG, n = 11), and the test group, which received digitally 3D-printed ocular prostheses (DG, n = 11). Microbiological analysis was conducted before prosthesis insertion and three months after using the ocular prosthesis. Swab samples were inoculated on blood agar, MacConkey's agar, and Sabouraud's dextrose agar (SDA) for isolating Gram-positive, Gram-negative, and fungal organisms, respectively. Subsequently, the plates were incubated at 37 degrees Celsius for 48 h. Additionally, a validated questionnaire was used for subjective clinical evaluation, including parameters such as comfort level, socket discharge, lacrimation, and frequency of lubrication for each ocular prosthesis patient in both groups.

RESULTS

Test group (DG, n = 11) exhibited a positive, though statistically insignificant, difference (p > 0.001) in microbial growth when compared to the control group (CG, n = 11). A statistically significant difference was observed in comfort levels between the two groups, with more comfort level within group II (test group) patients. While parameters such as discharge amount, discharge location, lacrimation and lubrication frequency displayed statistically insignificant differences between the two groups, all parameters showed improved results after three months of prosthesis use.

CONCLUSIONS

The choice of ocular prosthesis fabrication technique did not yield a statistically significant difference in anophthalmic flora. However, the 3D-printed acrylic resin, as an artificial eye material, displayed potential advantages in reducing the colonization of opportunistic pathogens. All subjective clinical evaluation parameters exhibited enhanced outcomes after three months of prosthesis use, emphasizing the need for an adaptation period during which patients complains are alleviated. In comparison with PMMA, 3D-printed acrylic resin showcased a certain degree of anti-colonization ability against pathogenic bacteria, along with a significant level of patient comfort, suggesting its potential as a promising material for ocular prostheses.

TRIAL REGISTRATION

This parallel double-blinded RCT has been registered at ClinicalTrials.gov with identification number: NCT05584865, 18/10/2022.

Protocol for detecting Helicobacter suis infection in gastric biopsies and serum by PCR and ELISA

Infection with Helicobacter suis, which causes many cases of gastric disease, is not reliably diagnosed. Here, we present a protocol for detecting H. suis infection. We describe steps for collecting gastric biopsies and sera from patients, preparing DNA for PCR, and targeting the H. suis-specific gene. We then define procedures for inoculating biopsies onto primary agar plates and transferring colonies to secondary agar plates. Finally, we detail whole-genome sequencing of bacteria and assess H. suis infection in sera with ELISA. For complete details on the use and execution of these protocols, please refer to Matsui et al.1.