Iranian Journal of Microbiology

Comprehensive review of preclinical evaluation strategies for COVID-19 vaccine candidates: assessing immunogenicity, toxicology, and safety profiles

2025-02-26T11:49:40+00:00

Following the worldwide spread of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there is a vital require- ment for safe and effective vaccines against Coronavirus disease 2019 (COVID-19). Therefore, several vaccine-candidate platforms have been designed, tested, and developed. Based on guidelines, preclinical studies are recommended to assess the safety and potency of COVID-19 vaccines in appropriate in vitro and in vivo settings. These studies provide essential infor- mation to describe the potential toxic properties of a vaccine and the formulation of vaccine agents during the preclinical trial phase. In toxicology studies, several factors must be considered, such as the appropriate animal species and strains, dosing timetable, mode of administration, time of sampling for biochemistry and antibody evaluation, and necropsy. Pharmacoki- netic/ biodistribution studies are not usually required for infectious disease prophylaxis vaccines unless the vaccine contains a novel substance. Evaluating their biodistribution is crucial for newly developed vaccines, such as lipid nanoparticles –mes- senger RNA (LNP-mRNA), DNA, and Viral vectors in non-replicated (VVnr), or recombinant virus vaccines. The review highlights the importance of preclinical studies in assessing the safety and efficacy of vaccine candidates. This guidance is essential for researchers and manufacturers to design effective vaccines that can progress to clinical trials safely.

Ceftazidime-avibactam susceptibility against Escherichia coli and Klebsiella pneumoniae

2025-02-26T11:50:34+00:00

Background and Objectives: Carbapenem-resistant Enterobacteriaceae (CRE) infections are extremely difficult to treat and have a high fatality rate. The study's primary goal was to determine the rate of ceftazidime-avibactam susceptibility using disc diffusion and E-Test, as well as to evaluate the agreement between the two methods.

Materials and Methods: A total of 124 multidrug-resistant (including carbapenem) Escherichia coli and Klebisella pneu- moniae isolates were included. Kirby Bauer's disc diffusion and E-test were used as the testing methods in this study. Results: In this study 37.5% and 33.9% of the isolates were susceptible to ceftazidime-avibactam by E test and Disc diffusion respectively. There were five isolates which produced discordant results. Among the 56 isolates there was 91% agreement between the two methods.

Conclusion: Among the discordant isolates the alarming disparity in zone size was a significant concern. Since CRE infec- tions are very common, an economical and practical method for testing ceftazidime-avibactam susceptibility is needed in all the clinical microbiology laboratories as it is a last resort drug.

Escherichia coli in septic arthritis: prevalence and antibiotics susceptibility patterns

2025-02-26T11:51:12+00:00

Background and Objectives: Septic arthritis (SA) is an orthopedic emergency mainly caused by bacteria. SA due to Esche- richia coli (E. coli) is rare with a poor prognosis. This study aimed to assess the occurrence and antibiotic resistance patterns of E. coli in SA patients in Quetta, Balochistan, Pakistan.

Materials and Methods: A cross-sectional study was conducted from March 2021 to December 2023. 220 samples were collected from SA patients from tertiary care hospitals. Joint aspirates (2ml) and blood (5ml) were analyzed for microbial and hematological examination.

Results: There were 5.45% samples positive, and 94.5% negative for E. coli. SA due to E. coli was more common in male (6.2%) than female (4.6%) patients with the knee being the most affected joint (6.3%). E. coli was more common in patients aged 41-60 years (7.7%), lower socioeconomic (6.9%), and illiterate (8.6%) patients. Suspected patients showed a significant increase in the levels of white blood cells (WBC), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), nota- bly, these levels were further elevated in E. coli-positive patients. The polymerase chain reaction (PCR) based identification of E. coli showed clear bands of 204bp of the 16S rRNA gene. Sequence analysis using the Basic Local Alignment Search Tool found high similarity with pathogenic E. coli from Egypt and China. The identified E. coli strain showed significant resistance to common antibiotics: amoxicillin, amoxicillin-clavulanate, ceftriaxone, sulfamethoxazole/trimethoprim, genta- micin, tetracycline, and erythromycin.

Conclusion: Antibiotic resistance in E. coli from SA patients suggests the need for accurate antibiotic selection to ensureprompt treatment.

Antimicrobial susceptibility, biofilm formation, and virulence genes among atypical enteropathogenic Escherichia coli stool isolates in Tehran, Iran

2025-02-26T11:52:12+00:00

Background and Objectives: Enteropathogenic Escherichia coli (EPEC) strains are emerging pathogens around the world, particularly among pediatric patients in developing countries, such as Iran. This study aims to examine and compare the characteristics of EPEC isolates from patients, who suffer from diarrhea versus isolates from patients without diarrhea. Materials and Methods: A total of 734 stool specimens [440 diarrheal (D), and 294 non-diarrheal (ND)] were examined. Thirty-six EPEC isolates (26 D, and 10 ND) were recovered by culture on MacConkey agar, followed by biochemical tests. Using PCR assay, eae+; stx1- and stx2-gene profiles of EPEC isolates were confirmed. The antimicrobial resistance was assessed by disk diffusion assay. Biofilm formation was assessed using a standard semi-quantitative microtiter plate assay. Virulence-associated genes, ehac, espA, fimA, flu, and sslE were detected.

Results: E. coli comprised 14% of all isolates were EPEC isolates that showed the highest sensitivity to imipenem (IPM) (100%) and gentamicin (GEN) (89%). However, susceptibility to ciprofloxacin and cotrimoxazole or trimethoprim\sulfa- methoxazole (SXT) was only 28% and 39%, respectively. About 61% of isolates produced Moderate Biofilm (MB), and the frequency of Weak Biofilm (WB) formers (27%) was higher among D and ND isolates, which carried virulence genes more frequently than D isolates.

Conclusion: Preventive measures by public health authorities can thwart the imminent crisis of widespread zoonotic con- tamination of the food chain in Iran. Our results may help clinicians make optimal therapeutic choices during the treatment of patients with severe EPEC infections, and assist epidemiologists devise policies for effective control of outbreaks.

Incidence of extended spectrum beta-lactamase (ESBL) producing Escherichia coli isolated from women with urinary tract infections in Jordan

2025-02-26T11:52:46+00:00

Background and Objectives: Urinary tract infections are one of the world's major health problems. In addition, clinical disorders may result from the presence of bacteria or fungi in urine. The aim of this study was to isolate Escherichia coli (E. coli) strains from midstream urine samples, and to determine molecular characterization of encoded Extended Spectrum Beta-Lactamase (ESBL) genes.
Materials and Methods: Collected urine samples were streaked on MacConkey, blood and EMB agar plates, then identifying E. coli isolates by using antibiotic susceptibility tests. ESBL production was measured using double disc diffusion. Furthermore, uniplex PCR was performed to identify two ESBL genes (bla_CTX and bla_TEM).
Results: Among 412 isolates, 198 (48.1%) were E. coli strains, followed by Staphylococcus saprophyticus, Klebsiella sp., Serratia sp., Enterococci sp. and Proteus sp. with frequency of 132 (32.0%), 51 (12.4%), 15 (3.6%), 10 (2.4%), and 6 (1.5%) respectively. Female participants who were between the ages of 40 and 49 years old, married, and pregnant were more likely to develop urinary tract infections (UTIs). E. coli species were present in 189 (95.5) of the recurrent UTIs. Regarding antimicrobial susceptibility testing of E. coli isolates, the highest percentage of resistance and susceptible rates were found for nalidixic acid (75.8%) and gentamicin (64.1%) respectively. Among the E. coli isolates, 25 (12.6%) were ESBL-producers. The bla_CTX-M gene was genetically confirmed in 20 (10.1%) of the isolates.
Conclusion: E. coli is the most common cause of UTI and ESBL production leads to increased resistance to common antibiotics and complicates treatment strategies.

Characterization of Escherichia coli outer membrane vesicles and the impact of pathogenic ones on NLR signaling pathways

2025-02-26T11:53:20+00:00

Background and Objectives: The secretion of outer membrane vesicles (OMVs) is a universal event among bacteria. In this study, we characterized OMVs from pathogenic and non-pathogenic strains of Escherichia coli and assessed the effect of pathogenic OMVs on NLR signaling pathways.

Materials and Methods: OMVs were extracted by differential centrifugation and characterized by scanning electron mi- croscopy (SEM), SDS-PAGE, Limulus amebocyte lysate (LAL) test, and nucleic acid extraction. Then, the Caco-2 cells were treated with the pathogenic OMVs to evaluate their effect on NLR signaling pathways.

Results: SEM showed that pathogenic and non-pathogenic strains produced OMVs in the range of 9-72.9 and 45-270 nm, respectively. The SDS-PAGE revealed that both OMVs had protein bands ranging from 25 to 100 kDa. The LAL test dis- played that the concentration of LPS was 2.368 and 0.055 EU/ml in pathogenic and non-pathogenic OMVs, respectively. The evaluation of nucleic acid contents showed no significant difference between both types of OMVs. The assessment of pathogenic OMVs' effect on NLR genes demonstrated that the expression level was changed in some genes.

Conclusion: The characterization of OMVs showed that both strains of E. coli secrete OMVs in different sizes and contents. Besides, it was revealed that OMVs can regulate gene expression.

Evaluation of cold atmospheric pressure plasma effects on Pseudomonas aeruginosa wound infection in a mouse model

2025-02-26T12:18:39+00:00

Background and Objectives: Antibiotic resistance in microorganisms is a significant global health concern. Cold atmo- spheric plasma is an innovative and promising method for inactivating bacteria. This study aimed to evaluate the effects of cold plasma on Pseudomonas aeruginosa in a mouse wound infection model.

Materials and Methods: The disk diffusion method was used to perform antibiograms after isolating the bacteria. A multi- drug-resistant strain was then selected. The bactericidal activity of cold helium plasma was investigated in vitro. The optimal cold plasma conditions were determined in the laboratory, with a flow of 3 liters per minute and a power of 1.1 watts. These conditions were later used for in vivo evaluations.

Results: In a laboratory study, helium gas plasma treatment for 8 minutes reduced P. aeruginosa by 2.5 logs. In the in vivo study, plasma reduced the wound's microbial load in mice by 1.9 log. The antibiotic treatment group had a 1.2 log reduction. Both plasma and antibiotic therapies had similar effects on microbial inactivation.

Conclusion: The overall evaluation of wound healing time and pathological features showed that plasma was generally better than antibiotic treatment. Plasma can inactivate P. aeruginosa in wounds and accelerate wound healing.

Infected burn wound healing using Hydroxy-propyl-methyl cellulose gel containing bacteriophages against Pseudomonas aeruginosa and Klebsiella pneumoniae

2025-02-26T12:19:14+00:00

Background and Objectives: Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) are the two leading bacterial strains involved in wound infections. These bacteria have developed broad resistance to antibi- otics, which has complicated their eradication. Additionally, the formation of a polymicrobial infection poses additional problems. Among alternative or complementary options, bacteriophages, viruses that parasitize bacterial hosts, have been promising.

Materials and Methods: In this research work, bacteriophages' therapeutic effects against P. aeruginosa- and K. pneumo- niae-infected burn wounds were studied. The infectious burn wound model was performed on Balb/C male mice, aged six weeks and weighing 25 ± 5 gr. The effects of the Hydroxy-propyl-methyl cellulose (HPMC) gel containing phage were inves- tigated compared to gentamicin. All of these actions were performed in separate groups for each bacteria and mixed group of bacteria (to test multi-bacterial infections treating) and the result were compared.

Results: Phages appear to be effective in gel forms. Pathologic samples of different groups confirmed therapeutic results of phages. These results at the microscopic level indicated the recovery of the tissue and the removal of the infection. Conclusion: The results of this study indicate that lytic phages are powerful biological tools for the treatment of bacterial infections in burn wounds, which can be considered as one of the alternatives for drug-resistant bacterial species and the high costs of antibiotics; though further animal and trial studies are needed. Meanwhile, the complications due to their widespread use in humans should be investigated in more details.

Evaluation of the relatedness between the biofilm-associated genes and antimicrobial resistance among Acinetobacter baumannii isolates in the southwest Iran

2025-02-26T12:19:52+00:00

Background and Objectives: Increasing antimicrobial resistance among Acinetobacter baumannii (A. baumannii) strains poses a significant challenge, particularly in intensive care units (ICUs) where these bacteria are common causes of hospital infections. Biofilm production is recognized as a key mechanism contributing to this resistance. This study aims to explore the relationship between biofilm production, the presence of biofilm-associated genes, and antibiotic resistance patterns in A. baumannii isolates obtained from ICU patients.
Materials and Methods: We collected 100 A. baumannii isolates from ICU patients at Nemazee Hospital in Shiraz, Iran. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disk diffusion method, and biofilm production potential was assessed through the tissue culture plate (TCP) method. Additionally, we investigated eleven biofilm-related genes (ompA, bap, csuE, epsA, bla_per-1, bfmS, pgaB, csgA, fimH, ptk, and kpsMII) in all isolates using polymerase chain reaction (PCR). The REP-PCR technique was utilized to analyze the genetic relatedness of the isolates (Fig. 4).
Results: All isolates displayed multi-drug resistance, with the highest resistance rates observed against ceftazidime, cefotaxime, and trimethoprim/sulfamethoxazole (100%). Gentamicin and amikacin showed the lowest resistance rates at 70% and 84%, respectively. A total of 98% of the isolates were capable of biofilm production, with 32% categorized as strong biofilm producers. The most frequently detected biofilm-associated genes included csuE (99%), bfmS (98%), ompA (97%), and pgaB (89%).
Conclusion: Biofilm production significantly contributes to the prevalence of multi-drug resistant A. baumannii strains. It is essential to implement effective antimicrobial stewardship and develop innovative anti-biofilm strategies to address this global health issue.

Direct MALDI-TOF MS-based method for rapid identification of microorganisms and antibiotic susceptibility testing in urine specimens

2025-02-26T12:20:51+00:00

Background and Objectives: Urinary tract infections (UTIs) are considered as a major public health issue, often causing complications. Although the traditional cultivation approach is reliable in diagnosis, it is time-consuming, leading to delay in treatment and contributing to antibiotic resistance due to suboptimal empirical treatments. This study aimed to evaluate the performance of a direct, rapid identification technique using MALDI-TOF MS for pathogen identification and antibiotic susceptibility testing in UTIs, aiming to reduce diagnostic time compared to standard culture methods.

Materials and Methods: In the span of a year, 458 monomicrobial urine samples were analysed using both the standard bacterial culture method and the direct MALDI-TOF MS-based method. Antibiotic susceptibility was directly tested on 20 samples using the disk diffusion method.

Results: The direct identification technique accurately identified 92.14% of microorganisms at the genus level and 60.92% at the species level within an hour, significantly faster than the 24 to 48 hours required by traditional culture methods. The direct antibiotic susceptibility test results were consistent with the standard post-culture method ranging from 60.00% to 100%. Conclusion: Direct identification using MALDI-TOF MS can improve UTI management by enabling faster pathogen iden- tification and targeted treatments, potentially reducing antibiotic resistance. Further studies are needed in terms of enhancing its clinical utility and reliability.

mecA and PVL genes in methicillin-resistant Staphylococcus aureus from clinical specimens: a cross-sectional hospital based study from Nepal

2025-02-26T12:21:28+00:00

Background and Objectives: Staphylococcus aureus has increasingly been associated with community and healthcare-as- sociated infections worldwide and contributes to treatment failures due to the emergence of multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA) strains. We aimed to determine the prevalence and antibiotic suscep- tibility pattern of MRSA isolated from patients attending a burn center and to detect mecA and PVL genes among MRSA isolates.

Materials and Methods: A cross-sectional hospital based study was conducted on 1950 clinical samples collected from hospital inpatients and outpatients of Kirtipur Hospital, which is a burn specialist hospital in Kathmandu, Nepal. Each sample underwent conventional cultural methods for bacterial isolates identification.

Results: Out of 1950 samples, 452 (23.2%) samples showed bacterial growth, of which 109 isolates (24.1%) were identified as Gram positive and 343 (75.9%) as Gram negative bacteria. Among the Gram positive bacteria, 53 (48.62%) were Staph- ylococcus aureus. Of the total S. aureus isolates, 40 (75.5%) were MRSA and 48 (90.6%) were MDR. Of the 40 MRSA isolates, 29 (72.5%) carried the mecA gene and 3 (7.5%) harbored PVL gene.

Conclusion: The high prevalence of MRSA in a burn unit underscores the need for more rigorous infection control practices that follow standard protocols to reduce MRSA transmission in both individuals and the hospital environment.

Immunological efficiency of Haemophilus influenzae type b polyribosyl ribitol phosphate combined with detoxified lipooligosaccharide in a rabbit model

2025-02-26T12:22:10+00:00

Background and Objectives: Haemophilus influenzae type b (Hib) could cause severe life-threatening infections in chil- dren. Combine vaccines have reduced invasive diseases, but disease management is still necessary. The aim of this research was to evaluate the immunological efficiency of polyribosyl-ribitol-phosphate combined with detoxified lipooligosaccharide (PRP-dLOS) in a rabbit model.

Materials and Methods: PRP purification, LOS extraction, and endotoxin evaluation were performed using modified CY medium, hot phenol, and limulus amebocyte lysate methods, respectively. Rabbit groups were immunized with PRP (10 µg), dLOS (20 µg), and PRP-dLOS combine (10 µg+20 µg) three times on days 0, 14, and 28. Serum samples were acquired on days 0, 14, and 28 post-immunization, then IgM and IgG levels were assayed by enzyme-linked immunosorbent assay.

Results: The concentrations of PRP, dLOS, and endotoxin were 1160 mg/L, 440 μg/mL, and 1450 EU/mL, respectively. PRP-dLOS combine led to a significant increase in IgG and IgM levels on days 14 and 28 post-immunization. After immu- nization with PRP-dLOS combine, serum levels of IgM and IgG increased from 16.8 to 29.3 µg/mL and 29.8 to 61.4 µg/mL, respectively from day 14 to day 28.

Conclusion: PRP-dLOS combine is a promising approach for Hib management without the fear of delay in immune respons- es and interference with other vaccines.

Investigation of new exopolysaccharides produced by strains of donkey milk

2025-02-26T12:22:56+00:00

Background and Objectives: It has been shown that strains of the genus Enterococcus isolated from donkey milk from different regions of the Republic of Armenia have antimicrobial activity, synthesize different polysaccharides and produce disaccharide polymers (glucose and galactose). The quantitative synthesis of polysaccharides (8-15%) depends on the com- position of the nutrient medium, temperature and growing time.

Materials and Methods:Species identification of LAB strains was confirmed by 16S rDNA gene sequencing method using universal primers LAB strains. The methods used for extraction, purification and detection of exopolysaccharides are based on the method of Sørensen et al. (2022). The antibacterial activity of EPS was investigated by agar diffusion assay. Determi- nation of the immunostimulating property was carried out using the ELISA method.

Results: The antimicrobial activity of the polysaccharide and antimicrobial protein-like fractions of the genus Enterococcus strains depends on its concentration, time of interaction with the test culture, and the species of the pathogenic bacteria.

Conclusion: The obtained results were shown that strains isolated from fermented donkey milk that are capable of synthesiz- ing two substances of different nature with high antimicrobial properties during the growth process are promising for further research and application for their use as probiotics and biopreparations in pharmaceuticals.

Urine amino acid and gamma aminobutyric acid level in COVID 19 patients

2025-02-26T12:23:41+00:00

Background and Objectives: SARS CoV2 has tropism for various tissues, including the respiratory tract, brain, endothe- lium, heart, kidney and liver. Neurological symptoms can also be seen in the clinical course of the disease, and anosmia is the most common. The main objective of our study was to examine the urinary amino acid profiles of moderately severe patients diagnosed with COVID-19 with a positive RT-PCR test and try to find metabolic changes associated with the infec- tion. Also, it was aimed to investigate the neuroinhibitory Gamma-Aminobutyric acid (GABA) levels in order to examine the physiopathology.

Materials and Methods: Thirty adult cases who were followed up in the infection clinic with positive SARS CoV 2 RT-PCR and diagnosed with COVID 19 disease were included in the study with consent. The amino acid profile of these patients' urine samples, 30 different amino acid levels and creatine levels were examined using the liquid chromatography-mass spec- trometry (LCMS) method on the SCIEX QTRAP 4500 device.

Results: The mean age of the patients is 40 ± 5. Elevated GABA in 28/30 cases, high hydroxylysine amino acid in 27/30 cases, low glycine in 30/30 cases were detected in the urine. The creatinine levels of the patients were found to be normal.

Conclusion: It has been thought that the height of GABA may be due to bacteria producing GABA as a result of the change in microbiota due to lactic acidosis, as well as that the virus may directly affect the brain and cause an increase in GABA.

Serological epidemiology analysis of Cytomegalovirus infection in pregnant women in Diwaniyah, Iraq

2025-02-26T12:24:16+00:00

Background and Objectives: Human cytomegalovirus (HCMV) infection is the most common cause of congenital infection during pregnancy. It is a major concern worldwide with a wide range of clinical outcomes in fetuses and newborns due to HCMV reactivation or reinfection during pregnancy. Primary maternal infection is best diagnosed by examining IgM and IgG antibodies. The current study aimed epidemiology survey of congenital HCMV infection in pregnant women in Diwan- iyah.

Materials and Methods: 600 blood samples were collected from pregnant women, between 18-45 years old, in Diwaniyah Governorate for 12 months, from January to December 2022, in regards to their place of residence (urban or rural). All sam- ples were monitored for both IgG and IgM antibodies against HCMV using rapid test and ELISA.

Results: Our findings showed a high positive rate for IgG (95.7%) and (96.2%) and a positive rate for IgM (1.5%) and (1.8%) for rapid test and ELISA, respectively. The highest IgG positive rate was in the age group 26-35 years (43.33%), while the lowest rate (13.0%) was in the age group 36-45 years. The HCMV infection rate in rural and urban areas were (96.48%) and (95.26%), respectively, with no significant differences (P value>0.05). Also, the rate of miscarriages among pregnant women infected with HCMV was 28.83%, and the highest infection rate (30.51%) was recorded in the age group 26-35 years.

Conclusion: The prevalence of HCMV infection and its related miscarriage among the studied population is relatively high with the highest rate in the age group of 26-35 years.

Frequency of BK virus genotypes in patients with colorectal cancer

2025-02-26T12:25:02+00:00

Background and Objectives: BK polyomavirus infection is prevalent and primarily asymptomatic, except for complica- tions in kidney transplant recipients. Furthermore, its involvement in a tumorigenic family necessitates consideration in various malignancies such as urogenital tumors, prostate cancer, colorectal cancer (CRC), and brain cancer.

Materials and Methods: This investigation encompassed 50 specimens of colorectal adenocarcinoma tumors, 50 adjacent tissues, and 40 urine samples, with patients having a mean age of 61 years ± 12.4 years. The detection of BK virus DNA VP1 gene and genotyping were carried out through nested-PCR and sequencing techniques.

Results: Through the utilization of nested-PCR, BK virus DNA was identified in 15/50 (30%) colorectal tumor samples and

3/50 (6%) adjacent tissues (p-value = 0.008). Additionally, 6/40 (15%) urine samples exhibited positive results for BK virus DNA. Notably, among these findings, 9/15 BK virus positive tumor tissues (60%) and 3/6 BK virus positive urine samples (50%) were confirmed to be positive for BK virus subtype 4 (p-value < 0.001), whereas 2 tumor samples and 3 urine samples were attributed to BK virus type 1b2.

Conclusion: It is imperative to enhance one's understanding of the etiological and risk factors pertaining to cancers. The present findings offer substantiation of a potential correlation between BK virus infection and colorectal cancer. BK virus genotype 4 was found to be dominant among the CRC patients in this study.

Exploring the antimicrobial potential of two haloarchaeal strains belonging to the genera Halopiger and Natrialba isolated from the Algerian Sahara

2025-02-26T12:25:56+00:00

Background and Objectives: Halophilic archaea commonly produce antimicrobial peptides (halocins), but only a few studies have been conducted on these molecules. This study explores the antimicrobial potential of two strains belonging to Halopiger and Natrialba genera, isolated from hypersaline environments in the Algerian Sahara. Antimicrobial compounds produced by these genera have rarely been studied before.

Materials and Methods: The antimicrobial activity of the strains was evaluated, along with the effects of UV radiation and culture conditions on growth and compound production. Stability assays and the effects of extracted compounds on target cells and peripheral blood mononuclear cells (PBMC) were assessed.

Results: The strains exhibited high anti-archaeal activities and cross-domain interactions. Producing extracellular com- pounds associated with halocin, in the cell-free supernatant (CFS). These compounds remained stable at different tempera- tures (4°C, 60°C, 80°C, and 100°C) and different pH ranges (4-10 and 5-11), with antimicrobial profiles changed in response to UV light. The active compounds resembled known halocins but displayed unique features suggesting the discovery of new halocins. Additionally, Natrialba extracts showed significant activity against PBMC.

Conclusion: This investigation confirms that Algerian saline soils are a promising source of interesting antimicrobial com- pounds.

Investigation of the optimal condition for the growth and biofilm development of Candida albicans on three dental materials

2025-02-26T12:26:33+00:00

Background and Objectives: Candida albicans as pathogenic fungi cause conditions like oral candidiasis and dental caries. The critical role of biofilms in the pathogenicity of C. albicans necessitates the exploration of conditions that promote their growth and development. Our study aimed to delineate the optimal conditions conducive to the proliferation and biofilm production of C. albicans on prevalent dental materials.

Materials and Methods: To approximate oral cavity conditions, culture media were enhanced with various glucose concen- trations to assess the growth and biofilm-forming capability of the fungus through growth curve analysis and crystal violet assays.

Results: The findings suggest that YPG medium augmented with 4% glucose presents as an optimal environment for C. albicans growth. Biofilm formation was most effectively promoted in RPMI medium supplemented with the same concen- tration of glucose. Composite resin was identified as the substrate most susceptible to biofilm development by C. albicans under these conditions.

Conclusion: This investigation highlights the necessity of accounting for microbial activity and material characteristics in the prevention and management of dental biofilm formation. Our research advances the understanding of in vitro cultivation of C. albicans, simulating the oral milieu more accurately and contributing to enhanced oral health management for individ- uals utilizing temporary dental fixtures.

In vitro investigations of coelomic fluid of Eisenia fetida: protein analysis, antioxidant activities and antibacterial effects on diabetic wounds' bacteria

2025-02-26T12:27:06+00:00

Background and Objectives: Diabetes is a metabolic disorder characterized by elevated glucose levels, leading to com- plications such as infections and impaired wound healing. Diabetic wounds are prone to bacterial infections, with common pathogens including Staphylococcus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. Coelomic fluid of Eisenia fetida (CFEF) exhibits antimicrobial properties, making it a potential alternative to traditional antibiotics. This study aims to evaluate the in vitro antibacterial effects of CFEF on diabetic wound pathogens, alongside analyzing its protein con- tent and antioxidant activities.

Materials and Methods: This study used bacterial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC

25922, Bacillus subtilis ATCC 19659, and Pseudomonas aeruginosa ATCC 27853. CFEF was extracted using warm water and electric shock methods. Protein concentration was determined using the Bradford method, and protein analysis was con- ducted via Tricine SDS-PAGE. Antioxidant activities were evaluated using DPPH, FRAP, superoxide dismutase, and catalase assays. Antibacterial activities were tested by disc diffusion, MIC, and MBC methods.

Results: The study showed that CFEF exhibited significant antibacterial and antioxidant activities against common bacteria found in diabetic wound infections. The warm water shock method yielded superior results compared to the electric shock method.

Conclusion: CFEF demonstrates promising antibacterial and antioxidant properties, suggesting its potential as a natural

alternative for treating diabetic wound infections. Further research is needed to evaluate its clinical application and safety.

Phytochemical components and antibacterial activity of two populations of Senecio vulgaris L. essential oils as traditional medicine plant

2025-02-26T12:27:40+00:00

Background and Objectives: Senecio vulgaris L., a member of the Asteraceae family, has been widely employed in tradi- tional Iranian herbal practices for centuries. This research seeks to analyze and compare the essential oil compositions and antibacterial characteristics of two distinct populations of S. vulgaris.

Materials and Methods: Essential oils were obtained from the above-ground parts of these populations through hydrodis- tillation, and their chemical constituents were examined using gas chromatography-mass spectrometry. The antibacterial effectiveness of the essential oils against both Gram-positive and Gram-negative bacteria was evaluated employing the agar well diffusion technique.

Results: Monoterpene hydrocarbons were found to be dominated in both populations, with Humulene epoxide II being the primary constituent, constituting 17.87% in the first population and 21.55% in the second one. The agar-well diffusion method revealed significant antibacterial effects of the S. vulgaris essential oils. The findings indicated that the essential oil displayed heightened activity against Escherichia coli in both populations. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests indicated that Pseudomonas aeruginosa with concentrations of

400 µg/mL for both tests, was the most susceptible bacteria, while Streptococcus pyogenes with MIC = 800 and MBC>800 µg/mL was the most resistant in both populations of S. vulgaris.

Conclusion: This research highlights the significance of S. vulgaris as a valuable reservoir of monoterpene-rich oil ex- hibiting robust antibacterial characteristics, suggesting its potential use in the development of novel and naturally derived therapeutics for bacterial diseases.

Synergistic effects of Rhizobium, Bacillus and Arbuscular Mycorrhizal fungi on enhancing cotton growth

2025-02-26T12:28:12+00:00

Background and Objectives: Telangana district is renowned for its prominence in cotton production, a crop vital to the livelihoods of local farmers. For years, synthetic fertilizers have been relied upon to bolster yields, but escalating costs have shifted focus towards biofertilizers as a cost-effective and sustainable alternative.

Materials and Methods: A microbial consortium comprising Rhizobium sp. PKS, Bacillus sp. PU-7, and Funneliformis mosseae AMF was employed. Microbial identification was performed using 16S rRNA gene sequencing. Biochemical eval- uations of consortium-inoculated plants included measurements of protein, sugar, proline, and chlorophyll levels, along with IAA quantification.

Results: A consortium of Bacillus sp. PU-7, Rhizobium sp. Pks [NCBI OK663003, NCMR-MCC4960], and Funneliformis mosseae enhanced Mahyco cultivar growth. Treatment increased plant height, fresh and dry weight, and improved bio- chemical profiles (reduced proline, elevated IAA, protein, chlorophyll, and sugars). Soil field trials were undertaken in four cotton-producing regions of Mahabubnagar region confirmed for efficacy, with deep black soil promoting phytohormone synthesis (IAA-917.66 ± 2.51) and light black soil (IAA- 802 ± 2) enhancing plant growth.

Conclusion: Given these outcomes, the application of the tested bioinoculants and AMF spores is suggested as an effective strategy to enhance cotton development and yield in the soils of Mahabubnagar, potentially revolutionizing the district's agricultural practices.