Species Of Gram-negative Bacteria Research Articles

Design of Novel Saposin-like Bacteriocins Using a Hybrid Approach.

A multitude of approaches will be required to respond to the threat posed by the emergence and spread of antibiotic resistant pathogens. Bacteriocins have gained increasing attention as a possible alternative to antibiotics, as such peptide antimicrobials have mechanisms of action different from antibiotics and are therefore equally potent against antibiotic resistant bacteria as their susceptible counterparts. A group of bacteriocins known as saposin-like bacteriocins is believed to act directly on the bacterial membrane. Based on seven saposin-like leaderless bacteriocins, we have constructed a library of hybrid peptides containing all combinations of the N- and C-terminal halves of the native bacteriocins. All hybrid peptides were synthesized using in vitro protein expression and assayed for antimicrobial activity towards several pathogens. Of the 42 hybrid peptides, antimicrobial activity was confirmed for 11 novel hybrid peptides. Furthermore, several of the hybrid peptides exhibited altered antimicrobial spectra and apparent increase in potency compared to the peptides from which they were derived. The most promising hybrid, termed ISP26, was then obtained synthetically and shown to inhibit most of the Gram-positive species tested, including opportunistic pathogens and food spoilage bacteria. Additionally, ISP26 was shown to inhibit Acinetobacter, a species of Gram-negative bacteria frequently isolated from nosocomial infections. The activity of the hybrid library provides valuable insights into the design and screening of new active bacteriocins.

Delivery of endolysin across outer membrane of Gram-negative bacteria using translocation domain of botulinum neurotoxin

The emergence of multidrug resistant pathogens has outpaced the development of new antibiotics, leading to renewed interest in endolysins. Endolysins have been investigated as novel biocontrol agents for Gram-positive bacteria. However, their efficacy against Gram-negative species is limited by the barrier presented by their outer membrane, which prevents endolysin access to the peptidoglycan substrate. Here, we used the translocation domain of botulinum neurotoxin (BoNT) to deliver endolysin across the outer membrane of Gram-negative bacteria. The translocation domain selectively interacts with and penetrates membranes composed of anionic lipids, which have been used in nature to deliver various proteins into animal cells. In addition to the BoNT translocation domain, we have fused bacteriophage-derived receptor binding protein to endolysins. This allows the attached protein to efficiently bind to a broad spectrum of Gram-negative bacteria. By attaching these target-binding and translocation machinery to endolysins, we aimed to develop an engineered endolysin with broad-spectrum targeting and enhanced antibacterial activity against Gram-negative species. To validate our strategy, we designed engineered endolysins using two well-known endolysins, T5 and LysPA26, and tested them against 23 strains from six species of Gram-negative bacteria, confirming that our machinery can act broadly. In particular, we observed a 2.32 log reduction in 30 minutes with only 0.5 µM against an A. baumannii isolate. We also used the SpyTag/SpyCatcher system to easily attach target-binding proteins, thereby improving its target binding ability. Overall, our newly developed endolysin engineering strategy may be a promising approach to control multidrug-resistant Gram-negative bacterial strains.

Testusterol, a new sterol of the sponge species Xestospongia testudinaria from Phu Quoc island, Vietnam

A new sterol, named testusterol (1), and five known compounds (2-6) were isolated from the n-hexane and dichloromethane extracts of the sponge species Xestospongia testudinaria. Their chemical structures were elucidated based on extensive spectroscopic analyses (1D, 2D NMR, ESIMS and HRESIMS) and comparison with published data. The results of in vitro test (utilizing brine shrimp Artemia salina LEACH) showed that three extracts ethanol, dichloromethane, and ethanol/water, significantly inhibited Artemia salina with LC50 values ranging from 6.09 to 16.83 µg/mL. Remarkably, the new compound 1 exhibited potent inhibition against both Gram-positive (Staphyloccocus aureus, Bacillus subtilis, Lactobacillus fermentum), and Gram-negative (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa) bacteria species, with IC50 values of less than 12.0 nM and MIC ranging from 4.70 to 75.23 nM as determined by the broth-microdilution assay.

Development and clinical validation of a dual ddPCR assay for detecting carbapenem-resistant Acinetobacter baumannii in bloodstream infections.

Acinetobacter baumannii (A. baumannii, AB) represents a major species of Gram-negative bacteria involved in bloodstream infections (BSIs) and shows a high capability of developing antibiotic resistance. Especially, carbapenem-resistant Acinetobacter baumannii (CRAB) becomes more and more prevalent in BSIs. Hence, a rapid and sensitive CRAB detection method is of urgent need to reduce the morbidity and mortality due to CRAB-associated BSIs. A dual droplet digital PCR (ddPCR) reaction system was designed for detecting the antibiotic resistance gene OXA-23 and AB-specific gene gltA. Then, the specificity of the primers and probes, limit of detection (LOD), linear range, and accuracy of the assay were evaluated. Furthermore, the established assay approach was validated on 37 clinical isolates and compared with blood culture and drug sensitivity tests. The dual ddPCR method established in this study demonstrated strong primer and probe specificity, distinguishing CRAB among 21 common clinical pathogens. The method showed excellent precision (3 × 10-4 ng/μL, CV < 25%) and linearity (OXA-23: y = 1.4558x + 4.0981, R2 = 0.9976; gltA: y = 1.2716x + 3.6092, R2 = 0.9949). While the dual qPCR LOD is 3 × 10-3 ng/μL, the dual ddPCR's LOD stands at 3 × 10-4 ng/μL, indicating a higher sensitivity in the latter. When applied to detect 35 patients with BSIs of AB, the results were consistent with clinical blood culture identification and drug sensitivity tests. The dual ddPCR detection method for OXA-23 and gltA developed in this study exhibits good specificity, excellent linearity, and a higher LOD than qPCR. It demonstrates reproducibility even for minute samples, making it suitable for rapid diagnosis and precision treatment of CRAB in BSIs.

BACTERIAL PROFILE AND ANTIBIOTIC SUSCEPTIBILITY TEST AMONG DIABETES MELLITUS PATIENTS WITH GANGRENE IN SURABAYA

Background: Gangrene is a severe complication of damaged tissue that can occur in people with Diabetes Mellitus (DM), putting them at risk for bacterial infection. A pus culture can show diabetic gangrene patients' infecting bacteria. Purpose: Determine the prevalence of infection-causing bacteria and antibiotic sensitivity tests in diabetic gangrene patients at Haji Regional General Hospital, East Java Province, for January-December 2021. Method: The method used in this study is observational analytical cross-sectional, which is based on secondary data and is analyzed using the percentage formula and Chi-Square test. Result: The data obtained from 39 patients revealed 29 (74.4%) positive patients for bacterial infection. The Gram-negative bacteria was found to cause infection more frequently (72.41%) than the Gram-positive bacteria (27.59%). The prevalence of Gram-negative bacteria species most frequently from Escherichia coli (ESBL) 13.79% (4/29), Klebsiella pneumoniae 10.35% (3/29), Proteus mirabilis 10.35% (3/29). While the dominant Gram-positive bacteria a Methicillin-Resistant Staphylococcus aureus (MRSA) 10.35% (3/29). The antibiotic sensitivity test showed that Gram-negative group were susceptible to ertapenem, meropenem, amikacin, gentamicin, and piperacillin tazobactam while resistant to ampicillin and cefazolin. The antibiotic sensitivity tests showed that the Gram-positive group was susceptible to linezolid, vancomycin, and tigecycline while resistant to tetracycline and ciprofloxacin. Conclusion: It is important to screen the bacterial profile causing gangrene and their antibiotic susceptibility pattern in DM patients in order to give proper treatment to DM patients.

The identification of risk factors and outcomes of cerebrospinal fluid shunt infections caused by carbapenem-resistant gram-negative bacteria in children: a retrospective cohort.

Cerebrospinal fluid (CSF) shunt infections caused by gram-negative bacteria are difficult to treat given the limited treatment options and the emergence of carbapenem-resistant (CR) strains. This study aimed to evaluate the demographic and clinical characteristics of children with CSF shunt and external ventricular drain (EVD) infections caused by gram-negative bacteria, to identify the risk factors for acquiring CR CSF shunt infections, and to report on the clinical outcomes of these infections. A retrospective cohort study was designed to evaluate pediatric patients with CSF shunt and EVD infections caused by gram-negative bacteria between January 2013 and February 2023. A total of 64 episodes in 50 patients were evaluated. There were 45 (70.3%) CSF shunt infections and 19 (29.7%) EVD infections. The median (range) ages were 1.4 years (9 months-17.5 years) for CSF shunt infection patients and 4.2 years (1 month-17 years) for EVD infection patients. The most common isolated gram-negative bacteria species in CSF shunt infections were Pseudomonas spp. (12, 26.7%), followed by Escherichia coli (11, 24.4%), Klebsiella pneumoniae (9, 20%), and Enterobacter cloacae (5, 11.1%). In EVD infections, the most common isolated gram-negative bacteria species were Acinetobacter spp. (6, 31.6%), followed by Pseudomonas spp. (4, 21.1%) and E. coli (3, 15.8%). The carbapenem resistance rate was 26.3% (n = 5) in EVD infections and 26.2% (n = 11) in CSF shunt infections. When risk factors for carbapenem resistance were evaluated for CSF shunt infections, prior carbapenem treatment and a prolonged hospital stay > 7 days were risk factors for the CR group (p = 0.032 and p = 0.042, respectively). In definitive treatment, colistin was statistically more commonly used in the CR group (p = 0.049). When outcomes were evaluated, the 30-day mortality rate (18.2% vs 0%) was higher in the CR group, without a significant difference (p = 0.064). A prolonged hospital stay > 7 days and prior carbapenem exposure within 30 days were associated with CR shunt infections caused by gram-negative bacteria.

Synthesis, characterization, DNA/BSA-binding affinity and biological activity of dinuclear palladium(II) complexes with aromatic N-heterocyclic bridging ligand

Dinuclear palladium(II) complexes, [{Pd(en)Cl}2(μ-L)](NO3)2 (L is bridging ligand pirazine (Pd1), pyrimidine (Pd2), pyridazine (Pd3), phenazine (Pd4) and en is ethylenediamine), were synthesized and characterized. The interactions of the synthesized palladium(II) complexes with biomolecules such as DNA and BSA were studied using UV–Vis spectroscopy and fluorescence spectroscopy. Analysis of tumoricidal activity of investigated complexes, tested on several tumor cell lines of human and mouse origin, revealed that Pd1 and Pd2 exhibited weak cytotoxic potential at lower concentrations. However, Pd3 showed higher cytotoxicity effects on the human MDA-MB 468 breast carcinoma and A375 melanoma cell lines, while Pd4 exhibited tumoricidal potential against MDA-MB 468 cells and A549 human lung adenocarcinoma cells. Interestingly, A375 human melanoma cells were highly sensitive to Pd4 treatment similarly to the effect of cisplatin. Further, the antimicrobial effects of tested compounds were evaluated using different species of Gram-positive and Gram-negative bacteria, as well as yeasts. Pd1–Pd4 showed variable antimicrobial activity depending on the microorganism species. Among tested complexes, Pd4 exhibited the highest antimicrobial activity. The obtained data suggest that palladium(II) complexes might be further investigated as potential antitumor and antimicrobial agents.

Isolation and draft genome sequence of Enterobacter asburiae strain i6 amenable to genetic manipulation.

Enterobacter asburiae is a species of Gram-negative bacteria that is found in soil, water, and sewage. E. asburiae is generally considered to be an opportunistic pathogen, but has also been reported as a plant growth-promoting bacterium (PGPB), which may have beneficial effects on plant growth and development. However, genetic analysis of E. asburiae has been limited, possibly due to its redundant enzymes that digest exogenous DNA in the cell. Here, an E. asburiae strain i6 was isolated from soil in Nara, Japan. This strain was amenable to transformation and the one-step gene inactivation method based on λ Red recombinase. The transformation efficiency of the i6 strain with the 10 kb plasmid DNA pCF430 was at least four orders of magnitude higher than that of the previously sequenced E. asburiae strain ATCC 35953, which could not be transformed with the same plasmid DNA. A draft genome sequence of the i6 strain was determined and deposited into the database, allowing several factors that may determine transformation efficiency to be perturbed and tested. Together with the amenability of the i6 strain to genetic manipulation, the information from the i6 genome will facilitate characterization and fine-tuning of the beneficial and detrimental traits of this species.

Antibacterial Activity of Silver Nanoparticles Composed by Fruit Aqueous Extract of Abelmoschus esculentus (L.) Moench Alone or in Combination with Antibiotics

Nanoparticle applications are growing due to the unique properties that nanoparticles possess, which have gained the attention of researchers, and one of these applications is the use of inhibiting antibiotic-resistant bacteria. The current work aims to biosynthesize silver nanoparticles from the fruits of the okra plant Abelmoschus esculentus (L.) Moench and test their antibacterial activity alone or in combination with some antibiotics. The creation of silver nanoparticles was confirmed by altering the color of the mixture from light green to dark brown, in addition to employing spectroscopic methods to prove and explain the production of these particles, such as UV-vis, FTIR, XRD, and EDX. Scanning electron microscopy (SEM) was used to determine the shape and sizes of the particles created in the current study. The synthesized silver nanoparticles were tested alone or in combination with some antibiotics for their ability to inhibit four species of antibiotic-resistant MDR bacteria, three of which were Gram-negative and the fourth was Gram-positive bacteria. The results demonstrated that these bacteria were inhibited when using nanoparticles at all concentrations alone or in combination with antibiotics. AgNPs were found to be more effective against Gram-positive bacteria than Gram-negative bacteria. Therefore, Staphylococcus auricularis (8F) was the most sensitive bacteria at all concentrations, while Escherichia coli (3R) was the most resistant. The results of the combination of AgNPs with some antibiotics revealed that the best synergy was recorded when AgNPs mixed with Amoxicillin clavulanate against all species of Gram-negative bacteria, followed by ciprofloxacin, Ampicillin, and Fosfomycin.

Co-electrospun (polyvinyl alcohol/Lepidium perfoliatum seed gum)-polycaprolactone hybrid nanofibers for antibacterial wound dressing applications

Lepidium perfoliatum seed gum (LPSG) biopolymer was co-electrospun in a hybrid nanofiber (HNF) structure using polyvinyl alcohol and polycaprolactone polymers. The obtained results showed the improvement in the hydrophilicity of HNFs with an increase in the LPSG content. In-vitro assay showed two stages of degradation of HNFs (34% and 4% weight loss within 24 h and 14 days, respectively). The antibacterial assay also showed the antibacterial activity of HNFs against Gram-positive and Gram-negative bacteria species. The biocompatibility of the LPSG-based nanofibers was also justified by the MTT assay against L929 fibroblast cells (97.4% cell viability).

Bacterial Virus Forcing of Bacterial O-Antigen Shields: Lessons from Coliphages.

In most Gram-negative bacteria, outer membrane (OM) lipopolysaccharide (LPS) molecules carry long polysaccharide chains known as the O antigens or O polysaccharides (OPS). The OPS structure varies highly from strain to strain, with more than 188 O serotypes described in E. coli. Although many bacteriophages recognize OPS as their primary receptors, these molecules can also screen OM proteins and other OM surface receptors from direct interaction with phage receptor-binding proteins (RBP). In this review, I analyze the body of evidence indicating that most of the E. coli OPS types robustly shield cells completely, preventing phage access to the OM surface. This shield not only blocks virulent phages but also restricts the acquisition of prophages. The available data suggest that OPS-mediated OM shielding is not merely one of many mechanisms of bacterial resistance to phages. Rather, it is an omnipresent factor significantly affecting the ecology, phage-host co-evolution and other related processes in E. coli and probably in many other species of Gram-negative bacteria. The phages, in turn, evolved multiple mechanisms to break through the OPS layer. These mechanisms rely on the phage RBPs recognizing the OPS or on using alternative receptors exposed above the OPS layer. The data allow one to forward the interpretation that, regardless of the type of receptors used, primary receptor recognition is always followed by the generation of a mechanical force driving the phage tail through the OPS layer. This force may be created by molecular motors of enzymatically active tail spikes or by virion structural re-arrangements at the moment of infection.

Antimicrobial activity of ZnO-Ag-MWCNTs nanocomposites prepared by a simple impregnation–calcination method

Zinc oxide (ZnO) nanorods and ZnO nanostructures composited with silver (Ag) and multi-walled carbon nanotubes (MWCNTs) have been synthesized by a simple impregnation–calcination method and have been shown to be suitable for use as antimicrobial agents. The preparation method used for composite materials is very simple, time-effective, and can be used for large-scale production. Several analytical techniques, including X-ray diffraction (XRD), scanning electron spectroscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transmission infrared spectroscopy (FTIR), have been used to characterize the prepared ZnO-Ag-MWCNT composite materials. The effects on structural, morphological, and antimicrobial properties of (ZnO)100-x (Ag)x nanocomposites at various weight ratios (x = 0, 5, 10, 30, and 50 wt%) have been investigated. The antimicrobial properties of ZnO composited with Ag nanoparticles and MWCNTs towards both gram-positive and gram-negative bacteria species were studied. The effect of raw MWCNTs and MWCNTs composited with ZnO and Ag on the cell morphology and chemical composition of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was studied by SEM and EDS, respectively. It was found that composite materials made of ZnO-Ag-MWCNTs exhibit greater antibacterial activities toward the microorganisms E. coli and S. aureus than ZnO-Ag, which could be beneficial for efficient antimicrobial agents in water and air treatment applications.

Photocatalytic evaluation of synthesized MnO2/Fe3O4 NCs by Q. infectoria extract for removal Ni(II) and phenol: Study phytochemical, kinetics, thermodynamics, and antibioactivity

In the present study, the plant extract of the Quercus infectoria galls was used as a reducing, capping, and stabilizer agent for green synthesized MnO2 nanoparticles (NPs) and MnO2/Fe3O4 nanocomposites (NCs) due to its reduction ability from polyphenol and antioxidant content. The green synthesized nanomaterials have been characterized by various techniques such as FTIR, UV–vis, XRD, SEM, EDS, and TEM. The average size of about 7.4 and 6.88 nm was estimated for the NCs crystals of SEM images and XRD analysis by the Scherrer and Williamson-Hall methods. The green synthesized MnO2/Fe3O4 NCs (dosage: 0.1 g) have shown high photocatalytic activity for the removal of Ni(II) in acidic and basic solutions under visible irradiation (220 V lamp). The removal efficiency for the Ni(II) solution (3.6 × 10−3 M) at pH = 3 was increased to pH = 12 from 56 % to 98 %. The oxidase-like activity of MnO2/Fe3O4 NCs at different dosages (0.05, 0.1, and 0.15 g) for the removal and colorimetric of phenol (1 g/40 mL) in the presence 4-AAp (1 g) was seen after only 28, 13, and 5 s, respectively. The kinetic evaluation results showed the pseudo-second-order kinetics model closely matched the adsorption capacity theoretical values qe,cal (578.03, 854.70, 892.85, and 917.43 mg.g−1) and experimental values qe,exp (521.84, 839.74, 887.86, and 913.22 mg.g−1) at different initial pH solution (3−12) for Ni(II) removal. In addition, the investigation of isotherm models revealed that the Langmuir model (R2 = 0.9955) explains a better estimate for a monolayer and favorable removal of Ni(II) ions onto NCs. Also, the low Temkin constant, BT < 0 (0.0200 kJ.mol−1), and positive ∆H° value (0.103 kJ.mol−1.K−1) illustrated that Ni(II) removal is physical sorption and endothermic process. However, the obtained thermodynamic results showed the negative values ΔG° with the increase in temperature (303–318 K) toward a spontaneous removal process of Ni(II). Finally, the plant antioxidant (200 to 3200 μg/mL) and antimicrobial activities (0.001 to 0.1 g/mL) for plant extract, MnO2 NPs, and MnO2/Fe3O4 NCs were evaluated against Gram-positive and Gram-negative bacteria species.

Hygiene and environmental sanitation consequences on the spread of &lt;i&gt;Klebsiella species&lt;/i&gt; and its antibiotic resistance in a ruminant animal farm

This study assessed the sanitation and hygiene practices in an animal farm through walkthrough observation and one-on-one interviews, monitored the levels of selected air parameters in animal houses using portable air samplers, identified the Klebsiella species from the bacterial population in the nose and skin of selected ruminant animals, and skin of consented animal handlers; and examined the antibiotic sensitivity test (AST) on the confirmed Klebsiella (K.) isolates following standard procedures. Most handlers (77.78%) wash their hands before starting work without soap (55.56 %), with well (77.78 %) or spent water (22.22 %). A total of 181 and 132 distinct bacterial colonies and gram-negative bacteria species, respectively, were obtained. The highest bacteria count (28cfu/ml) was from Cattle nasal swab samples, while the lowest (17cfu/ml each) was from the skin samples of Goats and Sheep. Also, the highest gram-negative bacteria (24cfu/ml) was from sheep skin swab samples, while the least was from goat nasal swab samples. Eighteen of thirty-two presumed K. species were confirmed with colony characteristics and biochemical tests. Multidrug resistance (MDR) was prevalent in 77.7% of the confirmed K. species. Two-thirds of Klebsiella isolates in goats and cattle showed multidrug resistance, compared with 60% in Sheep and 100 % in handlers. Klebsiella's estimated resistance percentages against Penicillin, Cefuroxime, Ceftazidime, Nitrofurantoin, and Gentamicin were 100, 67.7, 50, 38.9, and 22.2, respectively. This study found a significant gram-negative bacteria load in the skin swabs of animal handlers, which will only worsen with inadequate personal hygiene and poor sanitation.

Microbial Primer: LuxR-LuxI Quorum Sensing.

Quorum sensing is a term describing bacterial cell-to-cell communication systems for monitoring and responding to changes in population density. This primer serves as an introduction to the canonical LuxR-LuxI-type quorum sensing circuits common to many species of Gram-negative bacteria. Quorum sensing can synchronize behaviours across a community. Different species employ quorum sensing strategies to control specific behaviours such as bioluminescence, virulence factor production, secondary metabolite production, and biofilm formation.

Elucidation of chemical compounds in different extracts of two Lavandula taxa and their biological potentials: Walking with versatile agents on the road from nature to functional applications

Due to their health-promoting and nutraceutical properties, lavenders are frequently employed in the food and pharmaceutical industries. Here, we focused on investigate the chemical profile of hexane, MeOH, and water extracts of leaf, flower, and root of L. pedunculata and L. stoechas and to assess their antioxidant, enzyme inhibitory, and antibacterial properties. The highest total polyphenolic and flavonoids contents were recorded from the water and MeOH extracts of the leaf and flower of L. stoechas, respectively. Our HPLC/MS/MS analysis detected over 90 secondary metabolites, consisting of both known and novel terpenoids, polyphenols, flavonoids, and their derivative. Water leaf extract of L. stoechas displayed significantly (p < 0.05) the highest antiradical, Cu2+ and Fe3+ reducing capacity while hexane extract of the leaf and MeOH extract of the flower of L. pedunculata revealed the best metal chelating ability and total antioxidant activity respectively. The hexane extract of the leaf of L. pedunculata exerted the highest acetylcholinesterase and tyrosinase inhibition activity, whereas the hexane extracts from L. stoechas leaf and L. pedunculata root recorded the highest ability to inhibit the butyrylcholinesterase and ⍺-amylase enzymes respectively. The water extracts of the leaf of the two species, besides the hexane extract of the leaf of L. pedunculata exerted the best inhibition effect against the α-glucosidase. The sensitivities of Gram-positive and Gram-negative bacteria species against different extracts at two different concentrations were tested based on agar well diffusion assay. According to the result, we found that the n-hexane extract of L. stoechas-flowers showed the highest antibacterial activity. In conclusion, the results suggest that both Lavandula species have promising potential as sources of bioactive agents for various industrial applications.

Therapeutic Potential of Marine Probiotics: A Survey on the Anticancer and Antibacterial Effects of Pseudoalteromonas spp.

Due to the increasing limitations and negative impacts of the current options for preventing and managing diseases, including chemotherapeutic drugs and radiation, alternative therapies are needed, especially ones utilizing and maximizing natural products (NPs). NPs abound with diverse bioactive primary and secondary metabolites and compounds with therapeutic properties. Marine probiotics are beneficial microorganisms that inhabit marine environments and can benefit their hosts by improving health, growth, and disease resistance. Several studies have shown they possess potential bioactive and therapeutic actions against diverse disease conditions, thus opening the way for possible exploitation of their benefits through their application. Pseudoalteromonas spp. are a widely distributed heterotrophic, flagellated, non-spore-forming, rod-shaped, and gram-negative marine probiotic bacteria species with reported therapeutic capabilities, including anti-cancer and -bacterial effects. This review discusses the basic concepts of marine probiotics and their therapeutic effects. Additionally, a survey of the anticancer and antibacterial effects of Pseudoalteromonas spp. is presented. Finally, marine probiotic production, advances, prospects, and future perspectives is presented.

The comparative survey of phenotypic methods and the 16S rRNA gene sequencing method for detecting genus and species of non-fermented gram-negative bacteria isolated from blood samples in Isfahan, Iran

Introduction: This study compared phenotypic methods and the 16S rRNA gene sequencing method to identify the genus and species of non-fermenting gram-negative bacilli isolated from blood culture samples. Objectives: The aim of this study was to evaluate the effectiveness of using the 16S rRNA gene sequencing method in detecting the genus and species of non-fermented gram-negative bacteria isolated from blood samples. Materials and Methods: A cross-sectional study was conducted from April 2019 to April 2020, including all patients who required sterile culture at AL Zahra and Kashani hospitals. Specimens were cultured in BACTEC and subjected to standard phenotypic methods. Subsequently, 16S rRNA gene sequencing was performed to detect gram-negative non-fermenting Bacillus bacteria at the genus and species level. A comparative evaluation was then conducted. Results: The study identified 30 bacteria. The 16S rRNA gene sequencing method observed that 83.3% of the diagnoses were Acinetobacter baumannii, while the phenotypic approach identified 86.7% as Acinetobacter. Conclusion: The results indicate a significant difference between the phenotypic method and 16S rRNA sequencing in detecting non-fermenting gram-negative bacilli (NFGNB).

The comparative survey of phenotypic methods and the BD Phoenix M50 automated microbiology system for detecting the genus of non-fermenting gram-negative bacteria isolated from blood samples in Isfahan, Iran

Introduction: A comparative study was conducted to identify the genus and species of non-fermenting gram-negative bacilli isolated from blood culture samples using phenotypic methods and the Phoenix method. Objectives: This study aimed to evaluate the Phoenix system compared to the currently available phenotypic process. Materials and Methods: This descriptive-analytical cross-sectional study evaluated 30 samples collected from 2019 to 2020 from patients at AL Zahra and Kashani hospitals who required blood cultures. The specimens were injected into BACTEC™. Positive cultures identified as non-fermenting gram-negative bacteria by the phenotypic method were included in the study and then evaluated using the Phoenix method to determine the genus and species of non-fermenting gram-negative bacteria. A comparison was then conducted. Results: The study identified 30 non-fermenting gram-negative bacteria. The Phoenix method revealed that 78.5% of the diagnoses were Acinetobacter, while the phenotypic approach identified 86.7% as Acinetobacter spp. Conclusion: The present study demonstrated a significant difference between the Phoenix and phenotypic methods in identifying the type of bacteria.

UDN-like disease in spawners of salmonid fishes from the Rega, Parsęta, Wieprza, and Słupia rivers in 2009-2012

Abstract Since 2007 in Poland, skin lesions have been observed in salmon (Salmo salar L.) and sea trout (Salmo trutta L.) entering Pomeranian rivers to spawn. The clinical picture of affected fish resembled ulcerative dermal necrosis (UDN), a disease of unknown etiology affecting mainly the scalps of wild salmonids. The aim of the 2009-2012 study was to determine with microbiological tests the etiological agent of the skin lesions observed in salmonids entering the Pomeranian rivers. During the study, a total of 13 species of Gram-negative bacteria belonging mainly to the Yersiniaceae, Enterobacteriaceae, and Pseudomonadaceae families were isolated and identified from the skin and kidneys of diseased fish. The Gram-positive bacteria isolated were aerobic, hemolytic granules of the genus Streptococcus. Mycological examinations on damaged fish body surfaces revealed yeasts of the genus Rhodotorula and fungi of the family Saprolegniaceae. The results of our study did not permit us to identify unequivocally the direct cause of the fish diseases analyzed since all the bacteria isolated during the study are normally found in aquatic environments. Some of the isolated bacteria identified were assumed to be potentially pathogenic to fish. The fungal infections observed were probably secondary and only exacerbated ongoing disease processes.