Inorganic and organic phosphate solubilization potential of Stenotrophomonas maltophilia

Most soils contain Phosphorus (P) in insoluble compounds as organic and inorganic forms which is unavailable to plants. Furthermore, phosphate solubilizing bacteria (PSB) play an important role in converting insoluble P to a bioavailable form through solubilizing and mineralizing inorganic or organic P. Therefore, this study aims to determine the ability of isolate a phosphate solubilizing bacterium (PSB), Stenotrophomonas maltophilia to solubilize inorganic and organic P. The bacterium was isolated from peat soil of West Kalimantan using Pikovskaya medium added with Ca3 (PO4)2 as the P source. The activity of organic P (acid phosphatase and phytase) was measured using p-nitrophenyl phosphate disodium (pNPP 0.115 M) and sodium phytate as the substrate of bacterial broth culture. Also, the optimization for inorganic and organic P solubilization by the bacterium was conducted. The maximum values of inorganic and organic phosphate solubilization was recorded to be 52.26 μg/mL and 44.51 U/mL (acid phosphatase), 0.13 U/mL (phytase) respectively. Optimum conditions found were temperature at 30 °C, pH 6.0 and in the presence of sucrose and beef extract, which serve as carbon and nitrogen sources, respectively. Therefore, it can probably be used as a biological fertilizer for plants.

Nematicidal Activity of Cyclopiazonic Acid Derived From Penicillium commune Against Root-Knot Nematodes and Optimization of the Culture Fermentation Process

Among 200 fungal strains isolated from the soil, only one culture filtrate of Aspergillus flavus JCK-4087 showed strong nematicidal activity against Meloidogyne incognita. The nematicidal metabolite isolated from the culture filtrate of JCK-4087 was identified as cyclopiazonic acid (CPA). Because JCK-4087 also produced aflatoxins, six strains of Penicillium commune, which have been reported to be CPA producers, were obtained from the bank and then tested for their CPA productivity. CPA was isolated from the culture filtrate of P. commune KACC 45973. CPA killed the second-stage juveniles of M. incognita, M. hapla, and M. arearia with EC50–3 days 4.50, 18.82, and 60.51 μg mL–1, respectively. CPA also significantly inhibited egg hatch of M. incognita and M. hapla after a total of 28 days of treatment with the concentrations > 25 μg mL–1. The enhancement of CPA production by P. commune KACC 45973 was explored using an optimized medium based on Plackett–Burman design (PBD) and central composite design (CCD). The highest CPA production (381.48 μg mL–1) was obtained from the optimized medium, exhibiting an increase of 7.88 times when compared with that from potato dextrose broth culture. Application of the wettable power-type formulation of the ethyl acetate extract of the culture filtrate of KACC 45973 reduced gall formation and nematode populations in tomato roots and soils under greenhouse conditions. These results suggest that CPA produced by P. commune KACC 45973 can be used as either a biochemical nematicide or a lead molecule for developing chemical nematicides to control root-knot nematodes.

Optimum cultural conditions to achieve the best biofilm formation and high level icaA transcription by Staphylococcus aureus

Background The aim of this study was to investigate the influences of different broth culture media supplemented with glucose, on the biofilm formation and ica expression of Staphylococcus aureus. The phenotypic ability to adhere to a polystyrene surface and to produce slime layer were evaluated using microtiter plate test (MtP) and Congo red tube test, respectively. Using PCR, the presence of ica locus in S. aureus strains was confirmed and subsequently, quantitative real-time RT-PCR was performed to investigate transcription of icaA in various media including Tryptic soy broth (TSB), Brain-heart infusion broth (BHIB), (Nutrient broth) NB and (Muller-Hinton broth) MHB contained 0, 0.25, 0.5, 1 and 2% glucose. Results Our results showed that although all of the studied strains adhered to the wells of polystyrene microtiter plates, the optimum rate of biofilm formation was observed for TSB medium contained 1% glucose, but biofilm formation was not significantly different in NB, MHB and BHIB media. Supplementation of all media with 1% glucose led to the highest production of biofilm formation and in all of media transcription of icaA was increased with glucose addition to one present. Conclusions The results of the present study indicated that TSB medium supplemented with 1% glucose was the most appropriate medium for evaluation of biofilm formation by S. aureus isolates.

Application of the principles of colloidal chemistry to obtain the purest preparation of tetanotoxin

If you take a broth culture of a tetanus bacillus and filter it through a Chamberland'a candle, then, as you know, you will get a completely transparent, sterile liquid with pronounced toxic properties.

Emergent transcriptional adaption facilitates convergent succession within a synthetic community

Taxonomic convergence is common in bacterial communities but its underlying molecular mechanism remains largely unknown. We thus conducted a time-series transcriptional analysis of a convergent two-species synthetic community that grew in a closed broth-culture system. By analyzing the gene expression and monitoring the community structure, we found that gene expression mainly changed in the early stage, whereas community structure significantly changed in the late stage. The significant change of gene expression occurred even at the very beginning, which was designated as “0 h effect”, suggesting the effect of species interaction on gene expression was inevitable. Besides, the effect of interaction on gene expression has a “population effect”, which means that majority species have greater impact on gene expressions of minority species than vice versa. Furthermore, gene set enrichment analysis revealed that among a total of 63 unique pathways (occupying about 50% of all the metabolic pathways in both species), 40 (63%) were consistently suppressed, 16 (25%) were conditionally expressed, and only 7 (11%) were consistently activated. Overall, they were strictly regulated by both time and initial structures. Therefore, we proposed that microorganism responses and the induced gene expression changes play important roles in the process of community succession.

A Longitudinal Model-Based Biomarker Analysis of Exposure Response in Adults with Pulmonary Tuberculosis

The identification of sensitive, specific and reliable biomarkers that can be quantified in the early phases of tuberculosis treatment and predictive of long-term outcome is key for the development of an effective short-course treatment regimen. Time-to-positivity (TTP), a biomarker of treatment outcome against Mycobacterium tuberculosis , measures longitudinal bacterial growth in Mycobacteria Growth Indicator Tube broth culture and may be predictive of standard time-to-stable-culture-conversion (TSCC). In two randomized phase 2b trials investigating dose-ranging rifapentine (Study 29 and 29x), 662 participants had sputum collected over six months where TTP, TSCC and time-to-culture-conversion were quantified. The goals of this post hoc study were to characterize longitudinal TTP profiles and to identify individual patient characteristics associated with delayed time to culture conversion. In order to do so, a nonlinear mixed-effects model describing longitudinal TTP was built. Independent variables associated with increased bacterial clearance (increased TTP), assessed by subject-specific and population-level trajectories, were higher rifapentine exposure, lower baseline grade of sputum acid-fast bacilli smear, absence of productive cough, and lower extent of lung infiltrates on radiographs. Importantly, sensitivity analysis revealed that major learning milestones in phase 2b trials, such as significant exposure-response and covariate relationships, could be detected using truncated TTP data as early as 6 weeks from start of treatment, suggesting alternative phase 2B study designs. The TTP model built depicts a novel phase 2B surrogate endpoint that can inform early assessment of experimental treatment efficacy and treatment failure or relapse in patients treated with shorter and novel TB treatment regimens, improving efficiency of phase 2 clinical trials.

Short Communication: In vitro antimicrobial and antimalarial screening of a crude extract of Streptomyces sp. AB8 isolated from Lapindo Mud Volcano Area, Sidoarjo, Indonesia

Arifiyanto A, Setyaningrum E, Nukmal N, Aeny TN. 2021. Short Communication: In vitro antimicrobial and antimalarial screening of a crude extract of Streptomyces sp. AB8 isolated from Lapindo Mud Volcano Area, Sidoarjo, Indonesia. Biodiversitas 22: 2817-2823. Streptomyces is a potential bacterial genus that has been investigated extensively as a source of natural microbial compounds. Its potential metabolites have been widely developed for pharmaceutical, pathogen control, and other applications in agriculture. This study aimed to determine the ability of the Streptomyces sp AB8 crude extract in inhibiting Plasmodium and pathogenic microbes. Streptomyces was cultured on Gause synthetic media for 10 days. The fermented broth culture media has dissolved in a 1:1 mixture of ethyl acetate and methanol. Biochemical characterization of this isolate has carried out using the standard methods. In-vitro antimalarial activity assay was performed using a chloroquine-sensitive Plasmodium falciparum strain 3D7. Fresh type O-positive human erythrocytes were suspended at 4 percent hematocrit in a complete medium to maintain culture. The inhibitory concentration (IC50) was determined using probit analysis. The results showed the extract of Streptomyces sp. AB8 contains phenolic and alkaloids. Streptomyces sp. AB8 extract can inhibit Dickeya zeae N-Unila 5, Dickeya zeae N-Unila 10, Aspergillus sp IK3, and Escherichia coli growth. The results also showed that the ICs0 value of extract against P. falciparum 3D7 was 17.56 ug/mL. Further research was needed to determine the types of purified bioactive compounds and their bioactivity.

The Efficacy of Topical Bacteriophage Semisolid Preparation on Burn Wounds Infected by Pseudomonas Aeruginosa

Objective: Recently, antibiotic resistance of post-burn infections caused by opportunistic pathogens, Pseudomonas aeruginosa, became complicated due to its innate and acquired resistance. Bacteriophage therapy containing virulent factors that infect their specific host bacteria can be evaluated as an alternative treatment.In this study,the topical formulation contains lytic phages compared to the antibioticinthe murine model of burn/infected wound healing.Methods & Materials: Lytic bacteriophages were extracted from hospital sewage and propagated in broth culture of P.aeruginosa(24 hours, 37°C) and subsequently filtered.The collected phages were recultured alongside P. aeruginosa. The plaques were observed as clear zones and added to the polyethylene glycol (PEG) base ointment. Twenty-four adult female mice were selected and divided into four groups. Asecond-degree burn wound wascreated on the back of the mice and infected with 100 microliters of 1×102 - 3×102 CFU/ml P. aeruginosa subcutaneously. After 24 hours, each group received one of these interventions: silver sulfadiazine, ointment contains bacteriophage, ointment without bacteriophage (PEG group),or no treatment. Burn wound size, physical activity, and body temperature (rectal) were recorded every other day. On the 10th day, mice were sacrificed through cervical dislocation. Thewound’s skin was cut and evaluated histopathologically.Results: Significant differences inthe burn wound sizeamongthe bacteriophage groupversus the PEG group, the bacteriophage group versus the no-treatment group, and the antibiotic group versus the PEG group (P= 0.001, P= 0.001, P= 0.002 respectively)were observed. Mice’s physical activity was gradually improved in all groups and showed significant differences (P<0.001). Body temperature analyses showed significantdifferences only when day 8th compared with day 2nd, 4th, and 6th (P=0.001, P=0.02, P=0.02 respectively). Histopathological results indicated optimal wound healing in both the antibiotic group and bacteriophage group. However, no significant differences were observed in microscopic histopathological criteria in any groups based on Fisher’s exact statistical tests.Conclusion:Formulated phage ointmenteffectivelyprevents and treats burn wound infection in mice with no allergic reactions.

Evaluation of a Domestic Steam Disinfector-Dryer Device for Disinfection of Health Care Workers’ Identification Lanyards

Background Fabric lanyards are commonly worn by health care workers (HCWs) and are known to harbor infectious organisms and contribute to the transmission of infection to HCWs and patients. A diverse range of nosocomial pathogens have been found on lanyards, but there are very few studies describing how to successfully disinfect lanyards to break the chain of transmission. Recently, a steam disinfector-dryer device has come on the market, which performs rapid disinfection against nosocomial pathogens and also dries the contents of the device. It was the aim of this study to evaluate steam disinfection-drying as a method to eliminate pathogens from lanyards. Methods Thirty-eight strips of new, unused, and autoclaved polyester neck lanyards (4 × 2 cm) were inoculated with 30 (12 Gram-positive + 18 Gram-negative) bacteria and one yeast organism. The inoculated lanyard fabric (five organisms per lanyard strip) was placed into a steam disinfector-dryer device and disinfected for 5 minutes and dried for 30 minutes, in accordance with the manufacturer’s instructions. Following disinfection and drying, the presence of viable organisms on lanyard fabric was evaluated using enhanced microbiological broth culture methods for 48 hours. Control lanyard strips were treated with organisms and left at room temperature without undergoing disinfection and drying procedures. Findings Steam disinfection-drying eradicated all test organisms from treated lanyards, with no culturable organisms detected following disinfection-drying, even when employing enhanced bacteriological culture conditions. All test organisms remained viable on the control lanyards. Conclusion/Application to Practice Steam disinfection-drying offers a simple method of decontaminating lanyards, producing dry lanyards for immediate reuse. Occupational health practitioners and hospitals should consider assessing the feasibility of adopting this method in their settings to aid in breaking the chain of transmission of nosocomial pathogens via contaminated lanyards.

Prevalence and Types of Bacteria Associated With Ocular Infections of Patients Visiting the Optometry Clinic of Federal University of Technology Owerri

The prevalence and types of bacteria associated with ocular infections were studied using swab samples from ocular infected patients attending the Department of Optometry, Federal University of Technology, Owerri clinic. A total of fifty specimens were collected from patients comprising fourteen males and thirty-six females with ocular infections and analyzed aseptically in the Biotechnology laboratory within thirty minutes of collection. The samples were maintained on peptone broth in test tubes and about 1 ml of the overnight peptone broth culture was transferred into sterile petri dishes containing the culture media (nutrient, blood and macConkey agar). Standard microbiological and biochemical protocols were used for isolation, characterization and identification of the bacterial isolates. All specimens had bacterial growth. Fifty-seven bacterial isolates; 35 Gram positive and 22 Gram negative bacteria were identified. These fell into twelve species; Bacillus sp., Corynebacterium sp., Pseudomonas aeruginosa, Haemophilus sp., Staphylococcus aureus, Lactobacillus sp., Klebsiella sp., Citrobacter sp., Proteus mirabilis, Streptococcus pneumoniae, Listeria sp. and Neisseria sp. The predominant bacterial species isolated was Bacillus sp. 17 (29.8%) while Streptococcus sp., Listeria sp., and Neisseria sp. were the least with 1 (1.8%) each. The prevalence rate of bacteria was higher among the female gender within the age group 21 -30 years. The burden of bacterial infections of the eyes is high. The prevalence and types of bacteria may not be exactly the same in every part of the world. To mitigate the burden of ocular infections, physicians need to comply with etiologic approach of diagnosis and treatment regimen.