Bacterial Culture Research Articles

The breath volatilome is shaped by the gut microbiota.

The gut microbiota is widely implicated in host health and disease, inspiring translational efforts to implement our growing body of knowledge in clinical settings. However, the need to characterize gut microbiota by its genomic content limits the feasibility of rapid, point-of-care diagnostics. The microbiota produces a diverse array of xenobiotic metabolites that disseminate into tissues, including volatile organic compounds (VOCs) that may be excreted in breath. We hypothesize that breath contains gut microbe-derived VOCs that inform the composition and metabolic state of the microbiota. To explore this idea, we compared the breath volatilome and fecal gut microbiomes of 27 healthy children and found that breath VOC composition is correlated with gut microbiomes. To experimentally interrogate this finding, we devised a method for capturing exhaled breath from gnotobiotic mice. Breath volatiles are then profiled by gas-chromatography mass-spectrometry (GC-MS). Using this novel methodology, we found that the murine breath profile is markedly shaped by the composition of the gut microbiota. We also find that VOCs produced by gut microbes in pure culture can be identified in vivo in the breath of mice monocolonized with the same bacteria. Altogether, our studies identify microbe-derived VOCs excreted in breath and support a mechanism by which gut bacterial metabolism directly contributes to the mammalian breath VOC profiles.

A Comparison of Semi-Solid, Liquid, and Temporary Immersion Bioreactor Systems for Effective Plant Regeneration of Gerbera jamesonii “Shy Pink”

Temporary immersion system (TIS) cultures are reported to be superior when compared to semi-solid (SS) and liquid (LQ) cultures for the in vitro plant regeneration of many plant species. In the present study, we used a TIS for plant regeneration of Gerbera jemesonii “Shy Pink” and compared the results with that of SS and LQ cultures. The number of shoots regenerated in the SS, LQ, and TIS cultures was 6.93, 3.13, and 3.03, respectively. The shoots regenerated with the SS and LQ cultures demonstrated 3.33 and 4.22% hyperhydricity, whereas the shoots regenerated with the TIS were healthy even though the number of shoots regenerated was less. The plantlets regenerated with the TIS demonstrated higher values for the number of roots, root length, biomass of the plantlets, leaf length/width, and area compared to the SS and LQ cultures. When the G. jemesonii “Shy Pink” plants were regenerated using the TIS, their levels of photosynthetic pigments were highest. The number of stomata on the abaxial surface of their leaves was 11.40, and the frequency of closed stomata was 59% for the plants regenerated with the TIS. The number of stomata was 21.4 and 14.5 for the plants regenerated with the SS and LQ cultures, respectively. Meanwhile, the frequency of closed stomata was 13% and 15% for the plants regenerated with SS and LQ cultures. Furthermore, G. jemesonii “Shy Pink” showed the highest survival of plants when regenerated in the TIS compared to SS and LQ cultures. The TIS was found to be the most suitable culture system for plant regeneration of G. jemesonii “Shy Pink” compared to SS and LQ cultures.

First report of anthracnose caused by Colletotrichum fructicola on winter jasmine (Jasminum nudiflorum) in China.

Winter jasmine (Jasminum nudiflorum Lindl.) is a medium-sized, deciduous shrub native to China that has become a popular choice among gardeners and landscapers. In 2020 to 2021, symptoms of anthracnose including brown necrotic spots, enlarged irregular lesions and leaf blight were observed on leaves of 20 winter jasmine shrubs in a public garden (22°34'58'' N; 113°56'23'' E) in Shenzhen, China, and with an estimated disease incidence of 65%. Tissues samples (6 × 6 mm2) surrounding the necrotic spots were surface sterilized with 75% ethanol for 30 s, followed by 2% NaClO for 1 min, then rinsed with sterile water for three times and dried with sterile filter paper. Tissues were placed on potato dextrose agar (PDA) medium and incubated at 25℃. After 3 to 7 d, pure cultures were obtained by transferring hyphal tips to new plates and 32 isolates producing Colletotrichum-like colonies were obtained from 40 tissues (isolation frequency=32/(4×10)=80%). Three representative isolates YCH09, YCH23 and YCH32 were selected for further study. Three selected isolates were identical in morphological characteristics. Colonies on PDA after 5 d at 25℃ were white to gray with cottony mycelia and grayish-white on the underside of the culture. Conidia (n = 60) measured 15.4 ± 1.1 µm (13.0 to 17.1 µm) in length and 5.4 ± 0.3 µm (4.9 to 6.0 µm) in width and were hyaline, single-celled, cylindrical with rounded ends. Appressoria (n = 15) measured 7.1 ± 0.1 µm (5.3 to 8.9 µm) in length and 5.2 ± 0.2 µm (4.1 to 6.2 µm) in width and were brown to dark brown, ovoid. These morphological features were aligned with those of Colletotrichum spp. (Weir et al. 2012). Sequences of five genetic markers of representative isolates YCH09, YCH23 and YCH32 including the rDNA internal transcribed spacer region, chitin synthase, partial actin, β-tubulin 2 and Apn2-Mat1-2 intergenic spacer and partial mating type (Mat1-2) region were 99.3 to 100% identical to the ex-type isolate of C. fructicola strain ICMP 18581 (Zhang et al., 2020). From the maximum likelihood phylogenetic tree which was constructed based on concatenated sequences, three representative isolates (YCH09, YCH23 and YCH32) were clustered with other isolates of C. fructicola. The above morphological and molecular characteristics suggest that causal agent was C. fructicola. Pathogenicity was tested using a whole-plant assay. Five healthy plants were inoculated by spraying a conidial suspension (1.5×104 conidia/ml; 20 ml per plant) of the isolate YCH23 onto the foliage (Marshall et al., 2023). Three noninoculated control plants were sprayed with sterile water. All plants were placed in a greenhouse at 25±2℃ with approximately 75% relative humidity. Yellow lesions appeared on leaves of inoculated plants as early as 4 days after inoculation (DAI), and irregularly shaped brown spots similar to those observed in the field were formed on 10 DAI. Noninoculated plants remained asymptomatic. Colletotrichum isolates resembling morphological characters of YCH23 were reisolated from all inoculated plants, then identified as C. fructicola by DNA sequence analysis. C. fructicola is a well-known fungus causing anthracnose on more than 63 plant species including agricultural and horticultural plants worldwide (Talhinhas and Baroncelli, 2021). To our knowledge, this is the first report of C. fructicola infecting J. nudiflorum plants in China. Since its potential risk to other horticultural plant species, precautions may be necessary to minimize the spread of this fungi.

Development and validation of a PMA-qPCR method for accurate quantification of viable Lacticaseibacillus paracasei in probiotics.

The effectiveness of probiotic products hinges on the viability and precise quantification of probiotic strains. This study addresses this crucial requirement by developing and validating a precise propidium monoazide combination with quantitative polymerase chain reaction (PMA-qPCR) method for quantifying viable Lacticaseibacillus paracasei in probiotic formulations. Initially, species-specific primers were meticulously designed based on core genes from the whole-genome sequence (WGS) of L. paracasei, and they underwent rigorous validation against 462 WGSs, 25 target strains, and 37 non-target strains across various taxonomic levels, ensuring extensive inclusivity and exclusivity. Subsequently, optimal PMA treatment conditions were established using 25 different L. paracasei strains to effectively inhibit dead cell DNA amplification while preserving viable cells. The developed method exhibited a robust linear relationship (R 2 = 0.994) between cycle threshold (Cq) values and viable cell numbers ranging from 103 to 108 CFU/mL, with an impressive amplification efficiency of 104.48% and a quantification limit of 7.30 × 103 CFU/mL. Accuracy assessments revealed biases within ±0.5 Log10 units, while Bland-Altman analysis demonstrated a mean bias of 0.058 Log10, with 95% confidence limits of -0.366 to 0.482 Log10. Furthermore, statistical analysis (p = 0.76) indicated no significant differences between theoretical and measured values. This validated PMA-qPCR method serves as a robust and accurate tool for quantifying viable L. paracasei in various sample matrices, including pure cultures, probiotics as food ingredients, and composite probiotic products, thereby enhancing probiotic product quality assurance and contributing to consumer safety and regulatory compliance.

Effect of L-arginine on cystic fibrosis Pseudomonas aeruginosa biofilms.

Cystic fibrosis (CF) airways are L-arginine deficient which may affect susceptibility to infection with certain pathogens. The potential impact of L-arginine supplementation on Pseudomonas aeruginosa, a common CF airway pathogen, is unclear. This study investigated the effects of L-arginine on P. aeruginosa biofilm cultures, using the laboratory strain PAO1 and multi-drug resistant CF clinical isolates. P. aeruginosa biofilms were grown in a chambered cover-glass slide model for 24 h, then exposed to either L-arginine alone or combined with tobramycin for an additional 24 h. Biofilms were visualized using confocal microscopy, and viable cells were measured via plating for colony-forming units. Increasing concentrations of L-arginine in bacterial culture medium reduced the biovolume of P. aeruginosa in a dose-dependent manner. Notably, L-arginine concentrations within the physiological range (50 mM and 100 mM) in combination with tobramycin promoted biofilm growth, while higher concentrations (600 mM and 1200 mM) inhibited growth. These findings demonstrate the potential of L-arginine as an adjuvant therapy to inhaled tobramycin in treating P. aeruginosa infections in people with CF.

Culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery

The objective of this study was to investigate the culture positivity and distribution of the conjunctival sac bacteria in the perioperative period of corneal refractive surgery. The selected time points of the perioperative period included before the use of antibiotic eye drops, before eye wash (after the use of antibiotic eye drops), after eye wash, and immediately after surgery. Conjunctival specimens obtained at the four time points were cultured to detect the positivity and distribution of bacteria. Before prophylactic antibiotic eye drops were administered, 49 eyes (50%) had positive bacterial culture results, with 45 isolates (91.8%) identified as Staphylococcus epidermidis. The culture positivity rates of the conjunctival sac specimens before eye wash, after eye wash, and immediately after surgery were 19.4%, 3.1%, and 4.1%, respectively. The difference was significant before and after the use of antibiotics and before and after eye wash (both P < 0.001). Staphylococcus epidermidis was the major pathogen in the conjunctival sac before corneal refractive surgery, and the culture positivity rate of the conjunctival bacteria was higher in males. Sixteen of 37 eyes (43.2%) with contact lenses had positive culture results, compared to 33 of 61 eyes (54.1%) without contact lenses (P > 0.05). The judicious preoperative use of antibiotic eye drops combined with the surgical sterile eye wash procedure maximised the removal of conjunctival sac bacteria. Skilled surgical manipulations generally did not increase the risk of infection.

KẾT QUẢ TÁN SỎI ĐƯỜNG MẬT XUYÊN GAN QUA DA ĐIỀU TRỊ SỎI ĐƯỜNG MẬT CHÍNH TẠI BỆNH VIỆN BÃI CHÁY TỪ 2021 ĐẾN 2023

Purpose: This study aimed to evaluate the outcomes of percutaneous transhepatic cholangioscopic lithotripsy (PTCS-L) using laser at Bai Chay Hospital. Patients and Method: Our study conducted 55 patients who have biliary stones intrahepatic and intra common bile duct and underwent PTCS-L from January 2021 to June 2023. Results: In this study, 55 patients were enrolled with the average age of the patients was 59.4 ± 16.4 years old, with a female-to-male ratio of 1.6:1. Clearance totally of stones in 45 patients (81,8%) and nearly clearance in 10 patients (18,2%). The mean procedure time for lithotripsy was 106 ± 51 minutes, and the average length of hospital stay was 17.4 ± 7.2 days. Complications accounting for 6 cases (10.9%), including pleural effusion, subcapsular biloma, and residual stone impaction. Bilirubin stones were found in all patients, and positive bile fluid culture rate in bacterial culture results in 85.2% cases. Conclusion: Based on the findings, percutaneous transhepatic cholangioscopic lithotripsy using laser was confirmed to be an effective and safe in treatment of biliary stones.

Genome reduction in novel, obligately methyl-reducing Methanosarcinales isolated from arthropod guts (Methanolapillus gen. nov. and Methanimicrococcus).

Recent metagenomic studies have identified numerous lineages of hydrogen-dependent, obligately methyl-reducing methanogens. Yet, only a few representatives have been isolated in pure culture. Here, we describe six new species with this capability in the family Methanosarcinaceae (order Methanosarcinales), which makes up a substantial fraction of the methanogenic community in arthropod guts. Phylogenomic analysis placed the isolates from cockroach hindguts into the genus Methanimicrococcus (M. hacksteinii, M. hongohii, and M. stummii) and the isolates from millipede hindguts into a new genus, Methanolapillus (M. africanus, M. millepedarum, and M. ohkumae). Members of this intestinal clade, which includes also uncultured representatives from termites and vertebrates, have substantially smaller genomes (1.6-2.2 Mbp) than other Methanosarcinales. Genome reduction was accompanied by the loss of the upper part of the Wood-Ljungdahl pathway, several energy-converting membrane complexes (Fpo, Ech, and Rnf), and various biosynthetic pathways. However, genes involved in the protection against reactive oxygen species (catalase and superoxide reductase) were conserved in all genomes, including cytochrome bd (CydAB), a high-affinity terminal oxidase that may confer the capacity for microaerobic respiration. Since host-associated Methanosarcinales are nested within omnivorous lineages, we conclude that the specialization on methyl groups is an adaptation to the intestinal environment.

First detection of Cupriavidus gilardii in a bovine neonatal diarrhea outbreak

BackgroundCupriavidus gilardii is an aerobic, gram-negative, motile, glucose-nonfermenting bacillus, first described in 1999. Typically, it exhibits low pathogenicity in humans, causing opportunistic infections primarily in individuals with compromised immune systems. This bacterium has been also found in various environmental sources such as plants and contaminated soils. Notably, there have been no documented cases of C. gilardii infections in animals.Case presentationThis case report outlines a bovine neonatal diarrhea outbreak that occurred in Northern Greece, during which C. gilardii was isolated. Faecal samples from 5-day-old calves were collected and transported to the laboratory for further examination. Bacterial culture and next generation sequencing techniques were employed to confirm the presence of this bacterium in the samples. Following the isolation and identification of C. gilardii from the samples, an autogenous vaccine was produced and administered to the cows within the farm. Subsequent to vaccination, a progressive reduction in calf diarrhea and deaths was observed, leading to their eventual complete resolution. To the best of our knowledge, this represents the first documentation of C. gilardii isolation from cases of bovine neonatal diarrhea.ConclusionThis case report presents the first isolation case of C. gilardii from animal samples and more specifically from calf faecal samples. It represents an important observation, providing evidence that this opportunistic human pathogen could contribute to clinical symptoms in animals.

Paenibacillus lautus: A new foe in endogenous endophthalmitis.

To discuss the diagnosis and management of a rare case of endogenous endophthalmitis (EE) caused by Paenibacillus lautus mimicking granulomatous uveitis in a child, highlighting the use of 16S rRNA gene amplicon sequencing as an accurate method to identify rare pathogens. A retrospective chart review of the clinical presentation, microbiologic workup-including microscopy, culture, antibiotic susceptibility, and polymerase chain reaction for pathogen DNA of clinical samples-and the clinical management of the case were recorded. A 13-year-old boy presented with decreased vision in the right eye for one month. On examination, he had uveitis with hypopyon and complicated cataract. The case underwent an anterior chamber tap followed by vitrectomy and lensectomy. The culture of the vitreous aspirate grew Gram-variable bacilli that could not be identified by conventional microbiological techniques. However, PCR-based sequencing of the 16S rRNA gene was performed, and the bacterium was identified as P. lautus. The patient subsequently developed rhegmatogenous retinal detachment, for which he underwent endo laser photocoagulation and oil tamponade. Four months later, silicone oil was removed, and an intraocular lens was implanted. At six weeks follow-up, the retina remained well attached, and intraocular pressure was maintained. P. lautus can cause EE and mimic granulomatous uveitis. Techniques such as 16S rRNA gene sequencing can significantly facilitate aetiological diagnosis in cases where conventional methods fail.

Evaluation of different operational conditions in a microbial electrolysis cell inoculated with a pure culture of Shewanella oneidensis for hydrogen production.

Hydrogen is a promising alternative to meet the world's energy demand in the future because of its energetic characteristics. Microbial electrolysis cell (MEC) produces hydrogen from organic matter using exoelectrogenic bacteria. Shewanella oneidensis stands out for having the capacity to produce hydrogen using different electron transfer mechanisms. The present research aims to evaluate the hydrogen production efficiency in a MEC inoculated with a pure culture of S. oneidensis in different operational conditions. Since the use of a catalyst accounts for most of the MEC cost, no catalyst was used for anode or cathode. Experiments were performed in semi-continuous and batch mode using different electrodes, voltages applied, and medium in aerobic and anaerobic conditions. The highest hydrogen production rate (HPR) was 0.107 m3 of H2/m3day obtained in a semi-continuous experiment using graphite plates and stainless steel electrodes. In batch experiments, a HPR occurred at 0.7V, with a value of 0.048 m3 of H2/m3day versus 0.037 m3 of H2/m3day with 0.9V. HPR was higher with carbon felt electrode (0.056 m3 of H2/m3day). However, current density dropped after 38h, with carbon felt electrodes, and did not recover. Results of the present research showed that the MEC using a pure culture of S. oneidensis can be considered an alternative for hydrogen production without using a catalyst. Also, S. oneidensis produced hydrogen in both anaerobic and aerobic conditions with low methane production. Optimization can be proposed to improve hydrogen production based on the operational conditions tested in these experiments.

Integrating double-labeling HCR-FISH into a multidisciplinary pipeline for biofouling assessment on austenitic stainless steel in brackish seawater circuit

This study modified and integrated a bioimaging method of hybridization chain reaction fluorescence in situ hybridization (HCR-FISH) into a pipeline for assessing biofouling on stainless steel (SS). A modified protocol of double-labeling HCR-FISH was directly applied to two surface types of SS grade EN 1.4404 to detect localized bacteria and sulfate-reducing bacteria (SRB) by targeting bacterial 16 S rRNA genes and dissimilatory sulfite reductase (dsrB) genes, respectively. The protocol was first validated using microbial pure cultures and materials before being integrated into a biofouling assessment pipeline of SS in a laboratory-scale brackish water circuit, incorporating electrochemical, surface, and molecular biology characterization analyses. The double-labeling HCR-FISH improved bioimaging of surface biofilm morphology and microbial distribution, surpassing monochrome staining methods. This method was compatible and complemented other microscopy techniques and molecular biological analyses, providing additional insights into the biofilms and deposits on the alloy surfaces. The implemented assessment pipeline for biofouling determination frequently detected the ennoblement phenomenon in the evolution of marine biofilm on SS surfaces. However, within the experimental timeframe, microbial activities in the brackish seawater circuit did not flourish significantly, resulting in minimal impact on the steel material. Additionally, surface type and roughness may correlate with microbial adhesion, biofilm growth, and the deformation of passivation layers in SS. Despite abundant sessile bacteria, particularly opportunistic microorganisms, on the steel surfaces, no direct correlations with biodeterioration phenomena or influences of surface roughness of an alloy and the presence of biofilm were conclusively established.

A colorimetric biosensor with infrared sterilization based on CuSe nanoparticles for the detection of E. coli O157:H7 in food samples.

Escherichia coli O157:H7 is a major threat to public health. At present, the detection methods for E. coli O157:H7 mainly include traditional bacterial culture, immunology (enzyme-linked immune-sorbent assay) and molecular biology techniques (polymerase chain reaction). These methods have the limitations of professional operation, waste of time and energy, and high cost. Therefore, we have developed a simple, fast, bactericidal colorimetric biosensor to detect E. coli. O157:H7. The entire process was completed in 80 minutes. The method has been successfully applied to milk and mineral water samples with satisfactory results, proving that the method is an effective method for real-time detection and inactivation of bacteria.

Evaluation of hydroponic systems for organic lettuce production in controlled environment.

Organic farming methods, including the use of organic substrates, fertilizers, pesticides, and biological control, are gaining popularity in controlled environment agriculture (CEA) due to economic benefits and environmental sustainability. However, despite several studies focusing on the preparation and evaluation of liquid organic fertilizers, none have explored the compatibility of these fertilizers with different hydroponic systems. Therefore, the objective of this study was to evaluate lettuce production using a liquid organic fertilizer under different hydroponic systems. Four distinct hydroponic methods were selected: nutrient film technique (NFT), deep water culture (DWC) (liquid culture systems), and Dutch bucket (DB), regular plastic container (RPC) (substrate-based systems). 'Green Butter' lettuce was grown using a liquid organic fertilizer (Espartan) for four weeks. Shoot growth parameters (e.g., shoot width, number of leaves, leaf area, foliar chlorophyll content, fresh weight, and dry weight) and root growth parameters (e.g., root length, fresh weight, and dry weight) were measured. The growth difference of lettuce under the DB and RPC systems was negligible, but the growth in RPC was 29% to 60% and 15% to 44% higher than the NFT and DWC systems, respectively, for shoot width, number of leaves, leaf area, shoot fresh weight and dry weight. Root parameters were nearly identical for the NFT and DWC systems but significantly lower (21% to 94%) than the substrate-based DB and RPC systems. Although lettuce grown in the NFT system showed the least growth, its mineral content in the leaf tissue was comparable or sometimes higher than that of substrate-based hydroponic systems. In conclusion, the tested liquid organic fertilizer is suitable for substrate-based hydroponic systems; however, further evaluation of different liquid organic fertilizers, and crop species is required.

Research Progress in the Prevention and Control of Hospital-acquired Infections in Neonatal Units

Neonatal hospital-acquired infections are an important problem affecting the health and life safety of newborns. This paper reviews the research progress on the prevention and control of hospital-acquired infections in neonatology, discusses the risk factors of hospital-acquired infections in neonatology, summarizes the effective preventive and control measures such as strengthening the training and education on hospital-acquired infections, reducing invasive diagnostic and therapeutic operations, implementing disinfecting and isolating measures, rationally using antibiotics, and improving immunity for newborns, etc., and introduces common monitoring and detection techniques such as bacterial culture and drug susceptibility testing, molecular biology testing techniques, and biomarker detection and application. marker detection and application, and other commonly used surveillance and detection techniques. Future research should focus on strengthening the monitoring and study of pathogen resistance, optimizing the diagnosis and treatment process, strengthening the infection prevention and control training for healthcare workers, improving the infection prevention and control system in neonatal hospitals, and carrying out multidisciplinary collaborative research, so as to effectively reduce the incidence of infections and safeguard the health and safety of neonates.

Valorization of Algal Biomass to Produce Microbial Polyhydroxyalkanoates: Recent Updates, Challenges, and Perspectives.

Biopolymers are highly desirable alternatives to petrochemical-based plastics owing to their biodegradable nature. The production of bioplastics, such as polyhydroxyalkanoates (PHAs), has been widely reported using various bacterial cultures with substrates ranging from pure to biowaste-derived sugars. However, large-scale production and economic feasibility are major limiting factors. Now, using algal biomass for PHA production offers a potential solution to these challenges with a significant environmental benefit. Algae, with their unique ability to utilize carbon dioxide as a greenhouse gas (GHG) and wastewater as feed for growth, can produce value-added products in the process and, thereby, play a crucial role in promoting environmental sustainability. The sugar recovery efficiency from algal biomass is highly variable depending on pretreatment procedures due to inherent compositional variability among their cell walls. Additionally, the yields, composition, and properties of synthesized PHA vary significantly among various microbial PHA producers from algal-derived sugars. Therefore, the microalgal biomass pretreatments and synthesis of PHA copolymers still require considerable investigation to develop an efficient commercial-scale process. This review provides an overview of the microbial potential for PHA production from algal biomass and discusses strategies to enhance PHA production and its properties, focusing on managing GHGs and promoting a sustainable future.

Bioaugmentation by enriched hydrogenotrophic methanogens into trickle bed reactors for H2/CO2 conversion

Biomethanation represents a promising approach for biomethane production, with biofilm-based processes like trickle bed reactors (TBRs) being among the most efficient solutions. However, maintaining stable performance can be challenging, and both pure and mixed culture approaches have been applied to address this. In this study, inocula enriched with hydrogenotrophic methanogens were introduced to to TBRs as bioaugmentation strategy to assess their impacts on the process performance and microbial community dynamics. Metagenomic analysis revealed a metagenome-assembled genome belonging to the hydrogenotrophic genus Methanobacterium, which became dominant during enrichment and successfully colonized the TBR biofilm after bioaugmentation. The TBRs achieved a biogas production with > 96 % methane. The bioaugmented reactor consumed additional H2. This may be due to microbial species utilizing CO2 and H2 via various CO2 reduction pathways. Overall, implementing bioaugmentation in TBRs showed potential for establishing targeted species, although challenges remain in managing H2 consumption and optimizing microbial interactions.

Antibiotics Utilization Pattern in a Children’s Medical Center in North of Iran

Background: The development of a system for rational use of antimicrobials seems mandatory. Furthermore, since hospitals do not share the same bacterial flora and have different patterns of antibiotic therapy the purpose of the present study is to perform a Drug Utilization Evaluation (DUE) on the pattern of antibiotic administration in patients hospitalized in 17 Shahrivar Pediatric Hospital, RASHT, Iran. Methods: In this descriptive cross-sectional study that was conducted in a one-year period (2021-2022), 560 patients were randomly selected and their medication data were collected based on the gender and age as well as the type, dose, duration of antibiotic therapy and the results of bacterial cultures and also susceptibility of the infectious microorganisms. Results: The average age of patients was 53.56 months with 46.9% of them being less than 24 months old. The highest rate of antibiotics administration belonged to the infectious diseases ward (30%) and 33% of antibiotics were prescribed by pediatric infectious diseases specialists. The result of most of the cultures was reported as negative (98.38%), the most prevalent microorganism was Escherichia Coli from urine cultures (2.38%) and Staphylococcus Aureus from sputum cultures (14.28%). The highest prescribed antibiotics were ceftriaxone (51.2%) and vancomycin (45.6%). It was determined the antibiotic stipend was 15.6% of the whole budget for purchasing medicine. Conclusions: It is necessary to develop a guideline regarding the prescription of antibiotics in children's departments, which reduces empiric treatment and the requirement to adjust the drug after a negative culture.

Phenolic Compounds Synthesized by Trichoderma longibrachiatum Native to Semi-Arid Areas Show Antifungal Activity against Phytopathogenic Fungi of Horticultural Interest

Fungal diseases are a major threat to the horticultural industry and cause substantial postharvest losses. While secondary metabolites from Trichoderma sp. have been explored for their antifungal properties, limited information exists on the phenolic compounds produced by less studied species like Trichoderma longibrachiatum. In this study, phenolic compounds were extracted from a liquid culture of T. longibrachiatum using various solvents and methods (conventional and ultrasonic-assisted). Phenolic compounds were quantified by spectrophotometry and identified by high-performance liquid chromatography with diode array detection (HPLC-DAD). The antifungal activity against Alternaria alternata and Fusarium oxysporum was determined by mycelial growth inhibition assays, maximum growth rate (µmax) by the Gompertz equation, and spore germination tests. Although no significant differences (p ≥ 0.05) were found between the extraction methods, the type of solvent significantly influenced the phenolic content (p ≤ 0.05). Extraction with 70% ethanol showed the highest content of phenolic compounds and flavonoids. More than eight phenolic compounds were detected. Further, this is the first report of the phenolics ferulic, chlorogenic and p-coumaric acids identification in T. longibrachiatum, along with flavonoids such as epicatechin and quercetin, among others. The 70% ethanolic extracts notably inhibited the mycelial growth of A. alternata and F. oxysporum, reducing their maximum growth rate by 1.5 and 1.4 mm/h, respectively. Furthermore, p-coumaric and ferulic acids significantly inhibited spore germination of both pathogens, with a minimum inhibitory concentration (MIC) of 1.5 mg/mL and a minimum fungicidal concentration (MFC) of 2 mg/mL. These findings demonstrate the potential of T. longibrachiatum and its phenolic compounds as viable alternatives for biological control in horticulture and postharvest disease management.

Multiplex PCR assay for the accurate and rapid detection and differentiation of Lactococcus garvieae and L. petauri.

Lactococcosis is a common bacterial fish disease caused by Lactococcus garvieae, L. petauri and L. formosensis. Although there are different PCR-based techniques to identify the etiological agent, none of these can differentiate these two bacteria without sequencing PCR-amplified fragments. In the present study, we developed a multiplex PCR assay for simultaneous detection and differentiation of L. garvieae and L. petauri. The specificity of the primers was validated against the bacterial DNA of the targeted and non-targeted bacteria. The sizes of the PCR amplicons were obtained as 204 bp for the DUF1430 domain-containing protein gene of L. garvieae, 465 bp for the Lichenan permease IIC component gene of L. petauri, and 302 bp for the teichoic acid biosynthesis protein F gene of both L. garvieae and L. petauri. The PCR amplicons were clearly separated by agarose gel electrophoresis. The multiplex PCR assay did not produce any amplification products with the DNA of the non-targeted bacteria. The multiplex PCR detection limits for L. garvieae and L. petauri were 5 and 4 CFU in pure culture and 50 and 40 CFU/g in spiked tissue samples, respectively. It takes less than 2 h from plate-cultured bacteria and 3 h from tissue samples to get results. In conclusion, the developed multiplex PCR assay is a rapid, specific, accurate, and cost-effective method for the detection and differentiation of L. garvieae and L. petauri and is suitable to be used for routine laboratory diagnosis of L. garvieae and L. petauri.