Aerobic Gram-positive Bacteria Research Articles

TA-Cloning for Diabetes Treatment: Expressing Corynebacterium Malic Enzyme Gene in E. coli.

Diabetes mellitus represents a persistent metabolic condition marked by heightened levels of blood glucose, presenting a considerable worldwide health concern, and finding targeted treatment for it is a crucial priority for global health. Gram-positive aerobic bacteria, predominantly inhabiting water and soil, are known carriers of various enzyme-encoding genetic material, which includes the malic enzyme gene that plays a role in insulin secretion. Corynebacterium glutamicum bacteria (ATCC 21799) were acquired from the Pasteur Institute and confirmed using microbiological and molecular tests, including DNA extraction. After identification, gene purification and cloning of the maeB gene were performed using the TA Cloning method. Additionally, the enhancement of enzyme expression was assessed using the expression vector pET-28a, and validation of simulation results was monitored through a real-time PCR analysis. Based on previous studies, the malic enzyme plays a pivotal role in maintaining glucose homeostasis, and increased expression of this enzyme has been associated with enhanced insulin sensitivity. However, the production of malic enzyme has encountered numerous challenges and difficulties. This study successfully isolated the malic enzyme genes via Corynebacterium glutamicum and introduced them into Escherichia coli for high-yield production. According to the results, the optimum temperature for the activity of enzymes has been identified as 39°C.

Complete genome sequence of Bacillus cereus A01.

Bacillus cereus, a class of facultative aerobic gram-positive bacteria, is frequently isolated from soil, growing plants, and the intestinal tract of insects and mammals. Here, we report the complete genome sequence of B. cereus A01, whose total genome length is 6,097,808 bp, with a GC content of 34.92%.

Targeted Clindamycin Delivery Systems: Promising Options for Preventing and Treating Bacterial Infections Using Biomaterials.

Targeted therapy represents a real opportunity to improve the health and lives of patients. Developments in this field are confirmed by the fact that the global market for drug carriers was worth nearly $40 million in 2022. For this reason, materials engineering and the development of new drug carrier compositions for targeted therapy has become a key area of research in pharmaceutical drug delivery in recent years. Ceramics, polymers, and metals, as well as composites, are of great interest, as when they are appropriately processed or combined with each other, it is possible to obtain biomaterials for hard tissues, soft tissues, and skin applications. After appropriate modification, these materials can release the drug directly at the site requiring a therapeutic effect. This brief literature review characterizes routes of drug delivery into the body and discusses biomaterials from different groups, options for their modification with clindamycin, an antibiotic used for infections caused by aerobic and anaerobic Gram-positive bacteria, and different methods for the final processing of carriers. Examples of coating materials for skin wound healing, acne therapy, and bone tissue fillers are given. Furthermore, the reasons why the use of antibiotic therapy is crucial for a smooth and successful recovery and the risks of bacterial infections are explained. It was demonstrated that there is no single proven delivery scheme, and that the drug can be successfully released from different carriers depending on the destination.

Study on optimized culture of microbial strains and their ability in wax removal and viscosity reduction of paraffin-based crude oil

High-viscosity paraffin-based crude oil is prone to wax deposition at low temperatures, hindering development and transportation efficiency while posing safety risks. Microbial technology offers a safe, eco-friendly, and economically viable solution. In this study, strain B-1 is isolated and cultivated optimally using statistical multifactorial synergistic optimization. Species identification reveals strain B-1 to be a new Gram-positive aerobic bacterium. After optimization, strain B-1′s growth activity increases by 11.5 %. Lipopeptide surfactants produced by strain B-1 reduce wax content and viscosity of the crude oil by 37.29 % and 23 %, respectively. It also shows a significant impact on long carbon chain heavy component hydrocarbon substrates, degrading C17-C40 hydrocarbons by 37.93 % on average. Moreover, strain B-1 transforms aggregated wax crystals into dispersed microcrystals, improving flowability. These findings offer a promising solution for enhancing reservoir development efficiency and ensuring pipeline transportation safety.

Structural and Functional Characterization of a Gene Cluster Responsible for Deglycosylation of C-glucosyl Flavonoids and Xanthonoids by Deinococcus aerius

Plant C-glycosylated aromatic polyketides are important for plant and animal health. These are specialized metabolites that perform functions both within the plant, and in interaction with soil or intestinal microbes. Despite the importance of these plant compounds, there is still limited knowledge of how they are metabolized. The Gram-positive aerobic soil bacterium Deinococcus aerius strain TR0125 and other Deinococcus species thrive in a wide range of harsh environments. In this work, we identified a C-glycoside deglycosylation gene cluster in the genome of D. aerius. The cluster includes three genes coding for a GMC-type oxidoreductase (DaCGO1) that oxidizes the glucosyl C3 position in aromatic C-glucosyl compounds, which in turn provides the substrate for the C-glycoside deglycosidase (DaCGD; composed of α+β subunits) that cleaves the glucosyl-aglycone C–C bond. Our results from size-exclusion chromatography, single particle cryo-electron microscopy and X-ray crystallography show that DaCGD is an α2β2 heterotetramer, which represents a novel oligomeric state among bacterial CGDs. Importantly, the high-resolution X-ray structure of DaCGD provides valuable insights into the activation of the catalytic hydroxide ion by Lys261. DaCGO1 is specific for the 6-C-glucosyl flavones isovitexin, isoorientin and the 2-C-glucosyl xanthonoid mangiferin, and the subsequent C–C-bond cleavage by DaCGD generated apigenin, luteolin and norathyriol, respectively. Of the substrates tested, isovitexin was the preferred substrate (DaCGO1, Km 0.047 mM, kcat 51 min−1; DaCGO1/DaCGD, Km 0.083 mM, kcat 0.42 min−1).

Eco-friendly bifunctional antibacterial and anticorrosive broad-spectrum rosin thiourea iminazole quaternary ammonium salt against microbiologically influenced corrosion

Bifunctional antibacterial and anticorrosive broad-spectrum rosin thiourea iminazole quaternary ammonium salt (RTIQAS) was investigated to inhibit microbiologically influenced corrosion (MIC) caused by anaerobic gram-negative sulfate reducing bacterium (SRB) Desulfovibrio vulgaris against X80 carbon steel and aerobic gram-positive bacterium Bacillus licheniformis against 316L stainless steel. It also indicated that RTIQAS was more effective than common commercial biocides THPS (tetrakis hydroxymethyl phosphonium sulfate) and glutaraldehyde at the same concentration against X80 carbon steel corrosion by D. vulgaris. In the molecular simulation, the interaction energy confirmed the favorable adsorption of RTIQAS on the metal surfaces, indicating its potential as an effective corrosion inhibitor.

Labile carbon-induced soil organic matter turnover in a subtropical forest under different redox conditions

Labile organic carbon (LOC) input strongly affects soil organic matter (SOM) dynamics, including gains and losses. However, it is unclear how redox fluctuations regulate these processes of SOM decomposition and formation induced by LOC input. The objective of this study was to explore the impacts of LOC input on SOM turnover under different redox conditions. Soil samples were collected in a subtropical forest. A single pulse of 13C-labeled glucose (i.e., LOC) was applied to the soil. Soil samples were incubated for 40 days under three redox treatments, including aerobic, anoxic, and 10-day aerobic followed by 10-day anoxic conditions. Results showed that LOC input affected soil priming and 13C-SOM accumulation differently under distinct redox conditions by altering the activities of various microorganisms. 13C-PLFAs (phospholipid fatty acids) were analyzed to determine the role of microbial groups in SOM turnover. Increased activities of fungi and gram-positive bacteria (i.e., the K-strategists) by LOC input could ingest metabolites or residues of the r-strategists (e.g., gram-negative bacteria) to result in positive priming. Fungi could use gram-negative bacteria to stimulate priming intensity via microbial turnover in aerobic conditions first. Reduced activities of K-strategists as a result of the aerobic to anoxic transition decreased priming intensity. The difference in LOC retention in SOM under different redox conditions was mainly attributable to 13C-particulate organic carbon (13C-POC) accumulation. Under aerobic conditions, fungi and gram-positive bacteria used derivatives from gram-negative bacteria to reduce newly formed POC. However, anoxic conditions were not conducive to the uptake of gram-negative bacteria by fungi and gram-positive bacteria, favoring SOM retention. This work indicated that redox-regulated microbial activities can control SOM decomposition and formation induced by LOC input. It is extremely valuable for understanding the contribution of soil affected by redox fluctuations to the carbon cycle.

Self emulsifying drug delivery system: norfloxacin model drug

Background Norfloxacin is a synthetic antibacterial fluoroquinolone that is poorly water soluble and active against a wide spectrum of gram-positive and gram-negative aerobic bacteria. The goal of this work was to create a self-nanoemulsion (SNE) as a colloidal dispersed drug delivery system for increasing norfloxacin dissolving rate, while also assuming intestinal lymphatic transport participation for such a nano-size system that would increase norfloxacin oral bioavailability. Methods Depending on the solubility of norfloxacin in various components, several formulations of liquid SNEDDS of the antibiotic were created using oleic acid (oil), tween20 (surfactant), and PEG200 (co-surfactant). To assess the presence of a nanoemulsion region, phase diagram was generated at various oil: surfactant: co-surfactant ratios. Results The in-vitro dissolution profile suggested an optimum norfloxacin SEDD formulation (F1) comprised of oleic acid (10%), tween 20 (45%), and PEG200 (45%), as opposed to commercially available traditional tablets. The F1 formula exhibited thermodynamic stability with a zeta potential of +60.78mV and a droplet size of 57.4nm. The F1 formula revealed an improved dissolving profile as compared to the commercial Tablet of norfloxacin. Conclusion Based on the findings, this study indicated that preparing norfloxacin as a liquid self-nanoemulsifying system improved the solubility and drug release of norfloxacin counteract the inconsistent bioavailability of the commercial tablet.

DETECTION OF EXTENDED SPECTRUM BETA LACTAMASES-PRODUCING KLEBSIELLA PNEUMONIAE ISOLATES IN CHRONIC OBSTRUCTIVE PULMONARY DISEASES PATIENTS

Objective: Chronic obstructive pulmonary disease (COPD) is the leading cause of morbidity and mortality worldwide which includes chronic bronchitis and emphysema. 80% of acute exacerbation of COPD (AECOPD) are triggered by respiratory viruses, atypical bacteria, and aerobic Gram-positive and Gram-negative bacteria. The aim of our study was to analyze the prevalence and antimicrobial susceptibility testing of Klebsiella pneumoniae and detection of extended spectrum beta lactamases (ESBL)-producing K. pneumoniae isolates from COPD patients. Methods: Sputum samples received from seventy-five diagnosed cases of COPD from the department of General Medicine and Chest Medicine, TSRM MCH and RC, Trichy, from March 2022 to August 2022. Direct Gram stain was done for all sputum samples. The suitable sputum samples were cultured. The identification of organism and antimicrobial susceptibility testing was done by standard microbiological techniques. Results: Out of seventy-five cases, 64% were males and 36% were females. Forty-seven were sputum positive, and the prevalence of Gram- negative bacteria was 64%. K. pneumoniae was the most common bacteria isolated (42.2%), followed by Pseudomonas aeruginosa (15.5%). Antimicrobial susceptibility testing of K. pneumoniae was sensitive to imipenem (78.94%), aminoglycosides (78.94%), amoxycillin-clavulinic acid (63.15%), ciprofloxacin (57.89%), Piperacillin-Taxobactam (57.89%), and the phenotypic tests showed 13 (68%) isolates were ESBL producers. Conclusion: This study showed that K. pneumoniae and P. aeruginosa are the most common organisms associated with AECOPD and increased rate of ESBL producers were observed.

Drug Utilization Evaluation and Impact of Pharmacist Interventions on Optimization of Piperacillin/Tazobactam Use: A Retrospective Analysis and Prospective Audit.

(1) Background: Piperacillin/tazobactam is a broad-spectrum antimicrobial encompassing most Gram-positive and Gram-negative aerobic and anaerobic bacteria. The inappropriate use of such broad-spectrum antibiotics is an important contributor to the rising rates of antimicrobial drug resistance worldwide. Drug utilization evaluation studies and pharmacists' interventions are vital to assess, develop, and promote the rational use of antibiotics. This drug utilization study aimed to evaluate the current utilization practice of piperacillin/tazobactam in a hospital setting and assess the impact of pharmacist intervention in improving its appropriate use. (2) Methodology: In this study, we used a retrospective cohort and a prospective cohort, a cross-sectional, observational method. It included a retrospective (Cycle A/pre-intervention-CycA) phase followed by an educational interventional phase conducted by the pharmacists. During the 2 months of educational intervention, pharmacists used several methods, including workshops, lectures, oral presentations, and the development and reinforcement of clinical pathways to promote the judicious use of piperacillin/tazobactam. This was followed by a prospective (Cycle B/post-intervention-CycB) phase to improve piperacillin/tazobactam usage appropriateness. The appropriateness criteria for this drug utilization evaluation were established based on antimicrobial guidelines, the published literature, the institutional antibiogram, consultation from the antimicrobial stewardship committee, and the product monograph (Tazocin). The appropriateness of CycA and CycB patients was compared using the measurable elements, including indication and dose based on renal function, timely order for cultures, de-escalation, and use of extended infusion protocol. (3) Results: The study population comprised 100 patients in both CycA and CycB. The mean age of the patients was 66.28 ± 16.15 and 67.35 ± 17.98, and the ratios of men to women were found to be 49:51 and 61:39 in CycA and CycB, respectively. It was observed that inappropriate usage was high in CycA patients, and the appropriateness was improved in CycB patients. A total of 31% of inappropriate empirical broad-spectrum use was found in CycA, and it was reduced to 12% in CycB patients. The transition of appropriateness was observed in all measurable criteria, which includes the optimized dose according to the renal function (CycA = 49% to CycB = 94%), timely bacterial culture orders (CycA = 47% to CycB = 74%), prompt de-escalation (CycA = 31% to CycB = 53%), and adherence to extended infusion institutional guidelines (CycA = 34% to CycB = 86%). (4) Conclusions: The study highlighted important aspects of inappropriate piperacillin/tazobactam use. This can be considerably improved by proper education and timely interventions based on the pharmacists' vigilant approach. The study results emphasized the need for surveillance of piperacillin/tazobactam usage by conducting similar drug utilization evaluations and practice to improve quality and safety in healthcare organizations globally.

Distribution and Genetic Diversity of Genes from Brazilian Bacillus thuringiensis Strains Toxic to Agricultural Insect Pests Revealed by Real-Time PCR.

Bacillus thuringiensis is a Gram-positive aerobic bacterium and the most used biopesticide worldwide. Given the importance of B. thuringiensis strain characterization for the development of new bioinsecticides or transgenic events and the identification and classification of new B. thuringiensis genes and strains to understand its distribution and diversity, this work is aimed at creating a gene identification system based on qPCR reactions utilizing core B. thuringiensis genes cry1, cry2, cry3, cry4, cry5, app6, cry7, cry8, cry9, cry10, cry11, vpb1, vpa2, vip3, cyt1, and cyt2 for the characterization of 257 strains of B. thuringiensis. This system was based on the Invertebrate Bacteria Collection from Embrapa Genetic Resources and Biotechnology and analyzed (a) the degree of correlation between the distribution of these strains and the origin of the substrate from which the strain was isolated and (b) between its distribution and geoclimatic conditions. This study made it possible to observe that the cry1, cry2, and vip3A/B genes occur homogeneously in the Brazilian territory, and some genes are found in specific regions. The biggest reservoir of variability is within B. thuringiensis strains in each region, and it is suggested that both geoclimatic conditions and regional crops interfere with the genetic diversity of the B. thuringiensis strains present in the region, and B. thuringiensis strains can constantly exchange genetic information.

Экологические особенности и биотехнологические возможности почвенных актинобактерий (обзор)

Actinobacteria are gram-positive aerobic and facultative anaerobic bacteria that tend to form branching hyphae capable of developing into mycelium. Their main role is in the decomposition of complex polymers in the soil: lignin, cellulose, chitin, humus substances; fertility formation; production of antibiotic substances; accumulation of biologically active compounds. Actinobacteria secrete into the environment a complex of secondary exometabolites of various compositions with aliphatic, carbocyclic, heterocyclic, nitrogenous, oxygen-containing and sulfur-containing compounds. Most of the isolated secondary metabolites have antibiotic, antimicrobial, antiviral, herbicidal, insecticidal properties. Biotechnological capabilities of soil actinobacteria producing biologically active substances with a wide range of environmental effects are used in the development of multifunctional biologics for various industries. Actinobacteria play a crucial role in optimizing the growing conditions of plants, and therefore there is a natural interest in studying the factors that influence the relationship between actinobacteria and various crops in specific soil conditions. The development of this issue is an important link in the ecological characterization of the soil microbial complex and it will help to develop the theoretical foundations for the targeted regulation of the interactions of actinobacteria with phytopathogenic microorganisms and insect pests. The purpose of this work is to analyze the ecological features and biotechnological capabilities of soil actinobacteria. The review describes the distribution of actinobacteria in various types of soils, including those with the presence of pollutant; the composition of the metabolites produced; relationships with other microorganisms, as well as biotechnological properties and the possibility of using actinobacteria for the development of biological products for agroecosystems.

Microbial Prevalence and Outcome of Diabetic Foot Ulcers in Patient’s Candidates for Minor Surgical Interventions

Background: Diabetes mellitus is a progressive disease with chronic complications such as diabetic foot infection, a significant difficulty that inevitably leads to gangrene and amputations.
 
 Objective: This study aims to determine microbial prevalence in diabetic foot infections, identify the significance of aggressive surgical therapy and minor amputations in limb salvage and the prevention of more proximal amputations, and identify predicting factors affecting the outcome of these surgical processes.
 
 Methods: In this cohort study, microbiological samples were collected from 62 patients with diabetic foot lesions who underwent debridement or minor amputations to determine the prevalence of microorganisms in diabetic foot infections. Then, they were followed up to determine the rate of saved limbs and the factors that affect the outcomes and rate of complications.
 
 Results: infections were mainly caused by aerobic Gram-positive bacteria (S. aureus) 53.5%, and aerobic Gram-negative bacteria of enterobacter species 40.4%. Regarding the outcome of surgical intervention, we found an 80.65% success rate of saving the limb with a 30.6% complication rate. Risk factors such as high levels of inflammatory markers and parameters of the severity of peripheral arterial disease showed significant association with the rate of complications and poor outcomes.
 
 Conclusions: Debridement and minor surgical amputations effectively prevent more proximal amputations in diabetic foot infections with a high chance of good results. At the same time, the common microorganism in our local population was S. aureus, followed by P. mirabilis, E. coli, and Klebsiella species in diabetic foot infections.

Dual recognition strategy for the rapid and precise detection of Bacillus cereus using post-modified nano-MOF and aptamer

Bacillus cereus is one of the most common foodborne pathogens and is widely distributed in foods, soil, water, plants and fodder. As an aerobic Gram-positive bacteria, B. cereus also plays an important role in liquor production, generating flavor enhancers and antibacterial substances. Therefore, a rapid and precise analysis strategy for this microbe is highly desired in food safety and sustainable food production. In this study, we propose an effective approach for B. cereus quantification using a dual recognition biosensor. B. cereus was specifically enriched with aptamer-functionalized magnetic beads, and then detected using the broad-spectrum fluorescent material, fragmented crystalline mannose-conjugated lectin-modified nano-MIL-53(Al)-NH2 (FcMBL@NM5AN). The dual recognition method was applied for specific quantification of B. cereus in the range of 20–2 × 108 CFU/mL with a limit of detection of 4 CFU/mL within 60 min. Recoveries ranged from 93.8%−100.8% in milk, rice, chicken meat, eggs, and distilled yeast as real samples were also obtained.

Isolation and Identification of Gram-Positive and Gram-Negative Bacteria from Infertility Patients in Tikrit City

The objectives of the current study were conducting a statistical study to find out the number of men with primary and secondary infertility, immune infertility, and unexplained infertility in the city of Tikrit. Isolation and identification of Gram-positive and Gram-negative aerobic bacteria, and the study of some patterns of sensitivity to antibiotics of the isolated bacteria. The results showed that the percentage of primary infertility was the highest among infertility diseases, as the percentage reached 57%, while the lowest percentage was for immunological infertility, as it amounted to 7%. While the percentage of secondary and unexplained infertility was 15% and 31%, respectively. About the bacteriological study, the results showed two types of isolates, single bacterial isolates (52%), mixed bacterial isolates (38%). Percentages of isolates from E. coli and Klebsiella spp. and Staphylococcus spp. and Streptococcus spp. were 100%, 12%, 18%, and 10%, respectively. E. coli showed total (100%) resistance to amoxicillin/clavulanic acid and ampicillin. 50% resistance to Nalidixic. Otherwise, Escherichia coli showed resistance of 40%, 20%, 60%, 20% and 50% to Imipenem, Amikacin, Gentamicin, Azithromycin and Cefepime respectively. Klebsiella showed total (100%) resistance to amoxicillin/clavulanic acid and ampicillin. 40% resistance to Nalidixic. Otherwise, Klebsiella spp. showed resistance of 20%, 10%, 10%, 40% and 20% to imipenem, amikacin, gentamicin, azithromycin and cefepime respectively. Staphylococcus aureus showed complete resistance to penicillin, oxacillin and cefoxitin. 10%, 0%, 30%, 30%, 0%, 90% and 50% are resistant to gentamicin, nitrofurantoin, erythromycin, azithromycin, rifampicin, trimethoprim and ciprofloxacin respectively. Streptococcus spp. completely resistant to penicillin, oxacillin and cefoxitin. 30%, 0%, 20%, 10%, 0%, 70% and 30% are resistant to gentamicin, nitrofurantoin, erythromycin, azithromycin, rifampicin, trimethoprim and ciprofloxacin respectively.

Trka milosrđa - kada čovekoljublje pomera granice

Diphtheria is an infection of the respiratory tract or skin with systemic intoxication caused by aerobic gram-positive bacteria, Corynebacterium diphtheriae. Epidemiology of infection and clinical manifestations of the disease vary in different parts of the world. In the past, this disease was among the leading causes of child mortality and occurred in massive outbreaks. Developed at the end of the 19th century, diphtheria antitoxin (DAT) played a key role in the history of public health and vaccinology prior to the diphtheria-tetanus toxoid and combined vaccines against diphtheria, tetanus and pertussis with the acellular pertussis component (DTaP). One of the more significant events from the past that showcase the importance of DAT was the dire need for its use during the diphtheria outbreak in the town of Nome, Alaska. It was January, 1925, when Doctor Curtis Welch declared a diphtheria outbreak and sent a radio telegram to all major cities in Alaska, as well as to the US Public Health Service in Washington, D.C., begging for help. Despite the quarantine, the disease spread, and the only available serum supplies were discovered at a hospital in the small town of Anchorage, hundreds of kilometres away from Nome. The serum was delivered from Anchorage by train to the Nenana village, where the nearest railway station was located, and from there teams of sledding dogs were organised to take the serum to Nome in a relay dash. They needed to cross 1085 kilometers as fast as possible, in dire weather conditions. The teams took over from each other, pushing the limits of their endurance. The musher, the dog sled driver, had to be prepared for these conditions. All the dogs on the team had significant roles, but the lead dog was the key, and he had to be resourceful, strong and well trained. It took five and a half days (127 and a half hours), 20 people and more than 150 dogs for the so-called "Great race of mercy". A coordinated emergency delivery of this serum, thanks to the sled relay accomplished by Alaskan malamutes and Siberian huskies and their mushers in extreme weather conditions in order to save lives, left a great legacy in the history of vaccinology and public health. The most difficult parts of the relay were led by Siberian huskies, Balto and Togo and their mushers, Gunnar Kaasen and Leonhard Seppala, but it should be noted that most of the mushers were native Alaskans, Athabascans. This race, where the dogs pulled the sleds carrying the precious serum represents a dynamic illustration of the contribution of a non-human species to mass immunization in the history of vaccinology. Many dogs died during this relay, while their mushers suffered severe frostbite due to extremely low temperatures. Every single individual on our planet (both human and animal) plays a part, the significance of which should not be forgotten, in the historical chain of survival and not giving up the goal of improving the life of every living creature, while at the same time trying not to harm another living being. This unique example of cooperation between human and animal species emphasizes the importance of a human-animal relationship in the one health approach initiative.

Antibiotska terapija kod kritično obolelih pacijenata sa sepsom - od koncepta FK/FD do novih lekova

Early detection of sepsis and its severity is critical for initiating proper therapy, including antibiotics, as soon as possible to maximize survival chances. Understanding the pathophysiological changes in septic shock that impact antimicrobial pharmacokinetics and pharmacodynamics (PK/PD), understanding the basics of PK/PD, and knowing PK-PD strategies in septic shock patients are all critical for appropriate therapy. By definition multi-drug resistant (MDR) microorganisms are those with acquired non-susceptibility to at least one agent in three or more antimicrobial categories. In the race between bacteria and novel antibiotics development, unfortunately, the number of new antibiotics/indications is not keeping pace with resistance and needs, especially for MDR Gram-negative microorganisms. When we fast forward to the approved antibiotics in the last five years, the list is rather short. Lefamulin is a novel pleuromutilin antibiotic which manifests activity against most Gram-positive pathogens. Cefiderocol is an injectable siderophore cephalosporin. Like other b-lactam antibiotics, it inhibits Gram-negative bacterial cell wall formation by binding to penicillin-binding proteins. Imipenem/cilastatin/relebactam is a new b-lactam/b-lactamase inhibitor combination with activity against MDR Gram-negative bacteria, including many CRE but excluding Metallo-b-lactamase (MBL)-producing Enterobacterales and CRAB. Those three antibiotics were FDA approved in 2019 and European Medicines Agency (EMA) approved in 2020. Plazomicin is a new semisynthetic aminoglycoside with activity against several MDR Gram-negative organisms, including CRE (FDA-approved in 2018). Meropenem-vaborbactam is a fixed-dose combination product of a carbapenem and a cyclic boronic acid b-lactamase inhibitor with potent activity against resistant Gram-negative bacteria like Klebsiella pneumoniae carbapenemase (KPC)-producing CRE; it is inactive against CRAB (FDA-approved in 2017; EMA-approved in 2018). Eravacycline is a new completely synthesized fluorocycline. It has a high level of effectiveness against Grampositive and Gram-negative bacterial strains that have developed tetracycline-specific resistance mechanisms; it is inactive against Pseudomonas aeruginosa (FDAand EMA-approved in 2018). Concluding this list of recently approved antibiotics is omadacycline, novel aminomethylcycline and a derivative of minocycline, with a chemical structure similar to tigecycline. Like other tetracyclines, omadacycline inhibits bacterial protein synthesis and possesses broad-spectrum antibacterial activity against Gram-positive and Gram-negative aerobic, anaerobic, and atypical bacteria including CRAB. It is inactive against Pseudomonas aeruginosa (FDA-approved in 2018). There are three novel carbapenems sulopenem, tebipenem pivoxil hydrobromide and benapenem. There is a group of antibiotics in phase III clinical trials: the combination aztreonam/ avibactam, sulbactam/durlobactam, cefepime/enmetazobactam, cefepime/zidebactam, cefepime/taniborbactam. An interesting approach to antimicrobial treatment is antimicrobial drug repurposing. Drug combinations could be a strategy to extend the life of antibiotics in the XXI century due to the multi-targeting mechanisms of agents. New active substances are urgently required to stop the spread of antibiotic-resistant bacteria. However, it could be a rather cumbersome and expensive procedure. Antimicrobial misuse and/or overuse contribute greatly to this very important global healthcare problem.

Multi-drug and biocide-resistant Gram-positive bacteria prevalent on surfaces of veterinary clinics in Benue State, Nigeria

Objective: In this study, the common aerobic Gram-positive bacteria (GPB) contaminating veterinary clinic surfaces were isolated, and their susceptibility to antimicrobial agents (antibiotics and biocides) was determined. Materials and Methods: Standard cultural and biochemical procedures were used to process 62 swab samples collected from different surfaces in 4 veterinary clinics for the isolation and identification of GPB. The agar dilution technique was used to determine the sensitivity of the isolates to disinfectants, while the disc diffusion technique was used to determine the sensitivity to antibiotics. Results: Isolation rates in veterinary clinics I, II, III, and IV were 39.4%, 40.4%, 7.4%, and 12.8%, respectively. GPB were isolated from all the surfaces sampled. A total of 94 GPB isolates were recovered, comprising Bacillus species (51.1%), Staphylococcus species (38.3%), Corynebacterium species (6.4%), and Enterococcus species (4.3%). Only 13.8% of the GPB were resistant to at least one of the biocides tested. Multiple drug resistance to at least three classes of antimicrobial agents was exhibited by 95% of the isolates tested. Conclusion: The results of this study suggest that veterinary clinic environments and surfaces in Makurdi are reservoirs of wide varieties of antimicrobial-resistant GPB of veterinary and public health importance.

Intratumor microbiome features reveal antitumor potentials of intrahepatic cholangiocarcinoma

ABSTRACT Intrahepatic cholangiocarcinoma (ICC) is a rare malignancy with a high prevalence in China. This study aimed to characterize the ICC tissues’ bacterial metagenomics signature and explore its antitumor potential for cancer. In this study, 16S rRNA sequencing was carried out on 99 tissues to characterize the features of intratumoral microbiota, followed by single-cell RNA sequencing (scRNA-seq) and multilevel validation. The presence of microbial DNA in tissues was determined using staining, fluorescence in situ hybridization (FISH), and transmission electron microscopy (TEM). A Gram-positive aerobic bacterium, identified as Staphylococcus capitis, was cultured from fresh tissues. Meanwhile, scRNA-seq showed that intratumoral bacteria could be present in multiple cell types. Using 16S rRNA sequencing, we identified a total of 2,320,287 high-quality reads corresponding to 4,594 OTU (operational taxonomic units) sequences. The most abundant bacterial orders include Burkholderiales, Pseudomonadales, Xanthomonadales, Bacillales and Clostridiales. Alpha and Beta diversity analysis revealed specific features in different tissues. In addition, the content of Paraburkholderia fungorum was significantly higher in the paracancerous tissues and negatively correlated with CA199 (Carbohydrate antigen199) levels. The results of in vitro and in vivo experiments suggest that P. fungorum possesses an antitumor activity against tumors. Metabolomics and transcriptomics showed that P. fungorum could inhibit tumor growth through alanine, aspartate and glutamate metabolism. We determined the characteristic profile of the intratumoral microbiota and the antitumor effect of P. fungorum in ICC.

Tobramycin Nanoantibiotics and Their Advantages: A Minireview.

Nowadays, antimicrobial resistance (AMR) represents a challenge for antibiotic therapy, mostly involving Gram-negative bacteria. Among the strategies activated to overcome AMR, the repurposing of already available antimicrobial molecules by encapsulating them in drug delivery systems, such as nanoparticles (NPs) and also engineered NPs, seems to be promising. Tobramycin is a powerful and effective aminoglycoside, approved for complicated infections and reinfections and indicated mainly against Gram-negative bacteria, such as Pseudomonas aeruginosa, Escherichia coli, Proteus, Klebsiella, Enterobacter, Serratia, Providencia, and Citrobacter species. However, the drug presents several side effects, mostly due to dose frequency, and for this reason, it is a good candidate for nanomedicine formulation. This review paper is focused on what has been conducted in the last 20 years for the development of Tobramycin nanosized delivery systems (nanoantibiotics), with critical discussion and comparison. Tobramycin was selected as the antimicrobial drug because it is a wide-spectrum antibiotic that is effective against both Gram-positive and Gram-negative aerobic bacteria, and it is characterized by a fast bactericidal effect, even against multidrug-resistant microorganisms (MDR).