Aerobic Gram-negative Bacteria Research Articles

The detailed analysis of the microbiome and resistome of artisanal blue-veined cheeses provides evidence on sources and patterns of succession linked with quality and safety traits

BackgroundArtisanal cheeses usually contain a highly diverse microbial community which can significantly impact their quality and safety. Here, we describe a detailed longitudinal study assessing the impact of ripening in three natural caves on the microbiome and resistome succession across three different producers of Cabrales blue-veined cheese.ResultsBoth the producer and cave in which cheeses were ripened significantly influenced the cheese microbiome. Lactococcus and the former Lactobacillus genus, among other taxa, showed high abundance in cheeses at initial stages of ripening, either coming from the raw material, starter culture used, and/or the environment of processing plants. Along cheese ripening in caves, these taxa were displaced by other bacteria, such as Tetragenococcus, Corynebacterium, Brevibacterium, Yaniella, and Staphylococcus, predominantly originating from cave environments (mainly food contact surfaces), as demonstrated by source-tracking analysis, strain analysis at read level, and the characterization of 613 metagenome-assembled genomes. The high abundance of Tetragenococcus koreensis and Tetragenococcus halophilus detected in cheese has not been found previously in cheese metagenomes. Furthermore, Tetragenococcus showed a high level of horizontal gene transfer with other members of the cheese microbiome, mainly with Lactococcus and Staphylococcus, involving genes related to carbohydrate metabolism functions. The resistome analysis revealed that raw milk and the associated processing environments are a rich reservoir of antimicrobial resistance determinants, mainly associated with resistance to aminoglycosides, tetracyclines, and β-lactam antibiotics and harbored by aerobic gram-negative bacteria of high relevance from a safety point of view, such as Escherichia coli, Salmonella enterica, Acinetobacter, and Klebsiella pneumoniae, and that the displacement of most raw milk-associated taxa by cave-associated taxa during ripening gave rise to a significant decrease in the load of ARGs and, therefore, to a safer end product.ConclusionOverall, the cave environments represented an important source of non-starter microorganisms which may play a relevant role in the quality and safety of the end products. Among them, we have identified novel taxa and taxa not previously regarded as being dominant components of the cheese microbiome (Tetragenococcus spp.), providing very valuable information for the authentication of this protected designation of origin artisanal cheese.A8MAe52mDCf21YyaVzbpABVideo

Tackling carbapenem resistance: ceftazidime - avibactam in contemporary clinical scenarios

Antimicrobial resistance poses a formidable challenge in treating severe infections, with the prevalence of extended-spectrum beta-lactamase (ESBL) - producing, Klebsiella pneumoniae carbapenemase (KPC) - producing, and multidrug-resistant (MDR) organisms on the rise. This necessitates careful consideration of various factors, including local resistance patterns, patient-specific characteristics, and drug properties, in treatment decisions for critically ill patients. Ceftazidime-Avibactam demonstrates efficacy against aerobic Gram-negative bacteria and offers a crucial advancement against carbapenem-resistant organisms (CRO) with its effectiveness against key pathogens, including ESBL, AmpC, KPC, and OXA-48-producing Enterobacteriaceae and drug-resistant P. aeruginosa. Ceftazidime-Avibactam emerges as a valuable option for critically ill patients with limited treatment choices. The drug's excellent safety profile demonstrated in clinical trials, further positions it as a crucial addition to antimicrobial treatment options. As the global threat of drug-resistant bacteria grows, Ceftazidime-Avibactam plays a pivotal role in addressing this challenge and offers a promising solution for critically ill patients facing infections caused by antimicrobial-resistant pathogens. The article delves into therapeutic efficacy and the prospective role of Ceftazidime-Avibactam in managing MDR Gram-negative organisms, underscoring the critical role of appropriate antibiotic administration in reducing mortality associated with Gram-negative infections.

Deciphering the Mechanism by Which Carbon Dioxide Extends the Shelf Life of Raw Milk: A Microbiomics- and Metabolomics-Based Approach.

Microbial community succession in raw milk determines its quality and storage period. In this study, carbon dioxide (CO2) at 2000 ppm was used to treat raw milk to investigate the mechanism of extending the shelf life of raw milk by CO2 treatment from the viewpoint of microbial colonies and metabolites. The results showed that the shelf life of CO2-treated raw milk was extended to 16 days at 4 °C, while that of the control raw milk was only 6 days. Microbiomics analysis identified 221 amplicon sequence variants (ASVs) in raw milk, and the alpha diversity of microbial communities increased (p < 0.05) with the extension of storage time. Among them, Pseudomonas, Actinobacteria and Serratia were the major microbial genera responsible for the deterioration of raw milk, with a percentage of 85.7%. A combined metagenomics and metabolomics analysis revealed that microorganisms altered the levels of metabolites, such as pyruvic acid, glutamic acid, 5'-cmp, arginine, 2-propenoic acid and phenylalanine, in the raw milk through metabolic activities, such as ABC transporters, pyrimidine metabolism, arginine and proline metabolism and phenylalanine metabolism, and reduced the shelf life of raw milk. CO2 treatment prolonged the shelf life of raw milk by inhibiting the growth of Gram-negative aerobic bacteria, such as Acinetobacter guillouiae, Pseudomonas fluorescens, Serratia liquefaciens and Pseudomonas simiae.

Evaluating the Potential Safety Risk of Plant-Based Meat Analogues by Analyzing Microbial Community Composition.

Plant-based meat analogues offer an environmentally and scientifically sustainable option as a substitute for animal-derived meat. They contribute to reducing greenhouse gas emissions, freshwater consumption, and the potential risks associated with zoonotic diseases linked to livestock production. However, specific processing methods such as extrusion or cooking, using various raw materials, can influence the survival and growth of spoilage and pathogenic microorganisms, resulting in differences between plant-based meat analogues and animal meat. In this study, the microbial communities in five different types of plant-based meat analogues were investigated using high-throughput sequencing. The findings revealed a diverse range of bacteria, including Cyanobacteria, Firmicutes, Proteobacteria, Bacteroidota, Actinobacteriota, and Chloroflexi, as well as fungi such as Ascomycota, Basidiomycota, Phragmoplastophyta, Vertebrata, and Mucoromycota. Additionally, this study analyzed microbial diversity at the genus level and employed phenotype prediction to evaluate the relative abundance of various bacterium types, including Gram-positive and Gram-negative bacteria, aerobic, anaerobic, and facultative anaerobic bacteria, as well as potential pathogenic bacteria. The insights gained from this study provide valuable information regarding the microbial communities and phenotypes of different plant-based meat analogues, which could help identify effective storage strategies to extend the shelf-life of these products.

Microbial communities of a variety of 75 homemade fermented vegetables.

Fermentation is an ancient practice of food preservation. Fermented vegetables are popular in Eastern European and Asian countries. They have received a growing interest in Western countries, where they are mainly manufactured at domestic and artisanal scales and poorly characterized. Our aim was to investigate the microbial communities and the safety of French homemade fermented vegetables, in the frame of a citizen science project. Fermented vegetables and the data associated with their manufacture were collected from citizens and characterized for pH, NaCl concentration, and microbiology by culturomics and 16S DNA metabarcoding analysis. Lactic acid bacteria (LAB) and yeast isolates were identified by 16S rRNA gene sequencing and D1/D2 domains of the large subunit of the rRNA gene, respectively. The 75 collected samples contained 23 types of vegetables, mainly cabbage, followed by carrots and beets, and many mixtures of vegetables. They were 2 weeks to 4 years old, and their median pH was 3.56, except for two samples with a pH over 4.5. LAB represented the dominant viable bacteria. LAB concentrations ranged from non-detectable values to 8.7 log colony-forming units (CFU)/g and only depended on the age of the samples, with the highest most frequently observed in the youngest samples (<100 days). The 93 LAB isolates identified belonged to 23 species, the two mains being Lactiplantibacillus pentosus/plantarum and Levilactobacillus brevis. The other microbial groups enumerated (total aerobic bacteria, halotolerant bacteria, Gram-negative bacteria, and acetic acid bacteria) generally showed lower concentrations compared to LAB concentrations. No pathogenic bacteria were detected. Viable yeasts were observed in nearly half the samples, at concentrations reaching up to 8.0 log CFU/g. The 33 yeast clones identified belonged to 16 species. Bacterial metabarcoding showed two main orders, namely, Lactobacillales (i.e., LAB, 79% of abundance, 177 of the 398 total ASVs) and Enterobacterales (19% of abundance, 191 ASVs). Fifteen LAB genera were identified, with Lactiplantibacillus and Levilactobacillus as the most abundant, with 41 and 12% of total reads, respectively. Enterobacterales members were mainly represented by Enterobacteriaceae and Yersiniaceae. This study is the first wide description of the microbiota of a large variety of homemade fermented vegetables and documents their safety.

A Cross-Over Randomized Controlled Clinical Trial for Evaluation of Two Hygiene Protocols on Microbial Load, Tissue Health, and Opinion of Ocular Prosthesis Wearers

The recommendations for the wear and hygiene of ocular prostheses can vary among practitioners, and it is still a controversial theme in the literature. This clinical trial evaluated the microbial load, tissue health of the socket, and the participants’ opinions before and after the use of two hygiene protocols. Thirty ocular prosthesis wearers used either a Daily Protocol (DPt: hygiene once a day) or Weekly Protocol (WPt: hygiene once a week) for 5 weeks with a washout of 7 days. The microbial load was quantified by the colony-forming unit count of the aerobic bacteria, Candida spp., Staphylococcus spp., and Gram-negative bacteria. The tissue health of the socket was evaluated by scores, and patients’ opinion of the protocols was evaluated using the analogic visual scale (VAS). Data were analyzed by ANOVA Repeated Measures, Friedman, Cochran’s Q Test, Wilcoxon, Fisher, and Pearson’s chi-square tests considering p &lt; 0.05. There was no difference in the microbial load of the microorganisms (p &gt; 0.05). Both protocols improved socket inflammation (p = 0.005) and discharge (p &lt; 0.001); DPt improved edema (p = 0.021) and crusting (p = 0.020). There was no difference in patients’ rating responses (VAS) for all the questions of patients’ opinion (Q1: p = 1.0; Q2: p = 1.0; Q3: p = 1.0; Q4: p = 1.0; Q5: p = 1.0; Q6: p = 0.317; Q7: p = 1.0; Q8: p = 0.159). There was a correlation between eye drops/edema (p = 0.030), eye drops/pain (p = 0.016), microbial load with discharge, inflammation, eyelid edema, and pain. Inflammation was correlated with edema at baseline (p &lt; 0.001) and after DPt (p = 0.018), and with crusting at baseline (p = 0.003); edema was correlated with crusting at baseline (p &lt; 0.001); crusting was correlated with discharge after WPt (p &lt; 0.001). The protocols showed no effects on the microbial load of the anophthalmic socket and ocular prosthesis. However, better tissue health and patient acceptance were observed after both regimens.

Moxifloxacin loaded microspheres-composed gel for controlled release and enhanced penetration in ocular tissues: In vitro, ex vivo and in vivo proof of concept

Microspheres-enriched ocular gels are proposed in this work for the loading of a model quinolone antibiotic of broad-spectrum - moxifloxacin hydrochloride (MXF) - as an approach to achieve a controlled release profile and enhance drug's bioavailability in ocular milieu. MXF is a synthetic fluoroquinolone antibacterial agent used for treatment of ocular diseases caused by strains of aerobic gram positive and gram-negative bacteria, besides others. MXF-loaded Eudragit RS microspheres were prepared by emulsion solvent evaporation method, as previously described by us. Optimized microspheres were characterized and then formulated in an ocular gel. Hydrophilic polymeric base HPMC K100 was used as gelling agent. Ocular gel enriched with microspheres was evaluated for its physicochemical parameters, in vitro drug release, ex vivo corneal and scleral permeation and bioadhesion, in vivo primary eye irritation and in vivo efficacy study. The developed MXF microspheres dispersed in an ocular gel showed an in vitro drug release over a period 12 h, improved corneal and scleral penetration and increased therapeutic efficacy with a reduced administration frequency which may contribute to increase patient's compliance to ocular treatment.

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.

Molecular basis of the pleiotropic effects by the antibiotic amikacin on the ribosome

Aminoglycosides are a class of antibiotics that bind to ribosomal RNA and exert pleiotropic effects on ribosome function. Amikacin, the semisynthetic derivative of kanamycin, is commonly used for treating severe infections with multidrug-resistant, aerobic Gram-negative bacteria. Amikacin carries the 4-amino-2-hydroxy butyrate (AHB) moiety at the N1 amino group of the central 2-deoxystreptamine (2-DOS) ring, which may confer amikacin a unique ribosome inhibition profile. Here we use in vitro fast kinetics combined with X-ray crystallography and cryo-EM to dissect the mechanisms of ribosome inhibition by amikacin and the parent compound, kanamycin. Amikacin interferes with tRNA translocation, release factor-mediated peptidyl-tRNA hydrolysis, and ribosome recycling, traits attributed to the additional interactions amikacin makes with the decoding center. The binding site in the large ribosomal subunit proximal to the 3’-end of tRNA in the peptidyl (P) site lays the groundwork for rational design of amikacin derivatives with improved antibacterial properties.

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.

Whole-Genome Sequencing of the Novel Pseudomonas Strain TUM22785 Harboring blaPAM-1, Isolated from a Patient with Urinary Tract Infection in Japan.

Pseudomonas species are Gram-negative aerobic bacteria that cause opportunistic infections. Here, we report the whole-genome sequence of the Pseudomonas sp. strain TUM22785, isolated from an outpatient with a urinary tract infection at a medical institution in Japan. This strain harbors a metallo-β-lactamase (MBL) blaPAM-1 gene.

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.&#x0D; &#x0D; 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.&#x0D; &#x0D; 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.&#x0D; &#x0D; 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.&#x0D; &#x0D; 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.

Microbiology of Chronic Suppurative Otitis Media amongst Children Attending a Tertiary Health Facility in North-Western Nigeria

Background: Chronic suppurative otitis media (CSOM) is a global middle ear disease worst in developing nations of the world. The burden in our environment of repeated episodes of childhood CSOM, and the resultant difficulty in the management of these patients because of improper or inadequate treatment is quite worrisome.&#x0D; Aim: The aim of this study was to prospectively analyze the aspirated middle ear exudates of paediatric patients with CSOM for both facultative aerobic bacteria and fungi, with their antimicrobial sensitivity patterns.&#x0D; Materials and Methods: A total of 166 children clinically diagnosed with CSOM were enrolled in the study, of which 219 middle ear discharge samples were obtained using sterile disposable plastic Pasteur pipettes and cultured for microbial flora. Drug susceptibility testing for the isolated microbes was conducted using the Kirby‑Bauer disc diffusion method.&#x0D; Results: The ratio of facultative aerobic bacteria to fungi was 2.1: 1, while the ratio of Gram-positive to Gram-negative aerobic bacteria was 1: 1.7. The most common causative aerobic organisms isolated were Staphylococcus aureus 41/202 (20.3%), Pseudomonas aeruginosa 30/202 (14.9%), Klebsiella pneumonia 23/202 (11.4%), and Proteus mirabilis 21/202 (10.4%). Aspergillus species 47/202 (23.3%) and Candida albicans 21/202 (10.4%) were the commonest fungal isolates. The antimicrobial profile of aerobic isolates revealed maximum sensitivity to gentamycin (91.1%), ceftriaxone (90.1%), and ciprofloxacin (85.6%); while the isolated fungi were completely sensitive to all the antifungals.&#x0D; Conclusion: The main isolates were Gram-negative aerobic bacteria, though Gram-positive aerobes and fungi were also isolated. Their varying antimicrobial susceptibility brings to the fore, the therapeutic significance of these drugs in CSOM management.

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.

Soil bacterial diversity in the tropical dry deciduous forest of Ajodhya hills, Purulia, West Bengal

Introduction and objectiveAjodhya hill is one of the important regions of “Jungle Mahals”, a tropical dry deciduous forest with a huge number of water bodies located in Purulia, West Bengal. Soil signifies a composite ecosystem that includes a variety of microorganisms including bacteria. In this study, the bacterial diversity of soil samples from different sites of Ajodhya hill was estimated. Materials and methodsStudy sites include Ajodhya hilltop, Marble lake, Upper dam, Loharia lake, Thurga falls, and Vertical hill of Ajodhya. Soil samples from these regions were collected and different groups of bacterial populations were enumerated by colony forming unit (cfu). Physico-chemical parameters of soil samples were analysed. Results and discussionThe population of aerobic heterotopic, starch hydrolyzing, phosphate solubilizing, lipid solubilizing, nitrate reducing, spore forming, Gram-negative, and nitrifying bacteria varied from 9.43 to 12.55 × 106, 2.88 to 6.11 × 103, 6.07 to 9.23 × 103, 2.21 to 5.91 × 102,3.23 to 9.7 × 103, 6.81 to 12.30 × 105, 2.22 to 8.6 × 103, 2.7 to 8.63 × 103 cfu/g of dry soil respectively.The organic carbon content ranged from 0.39% to 0.68% in the soil sample collected. The available nitrogen, potassium, phosphate, and pH levels in the soil sample ranged from 42.55 to 144.68 mg/kg, 1661.61 to 3749.28 mg/kg, 153.37 to 349.36 mg/kg, and 5.4 to 8. Results of one-way ANOVA indicated significant variation (p < 0.05) in the bacterial population of the soil sample among the various sites. Hierarchical clustering analysis between the various bacterial groups present in the soil helped with unraveling the similitudes connecting them. The Renyi diversity index helped with understanding the diversity, richness, and evenness of the microbial population of the soil samples. ConclusionThe outcomes reveal the highest bacterial diversity in Vertical hill and the least diversity in Ajodhya hilltop. The highest value for the Berger-Parker index found on the Ajodhya hilltop shows that the dominant species represent the larger part of the entire bacterial population of the hill. This variation in the diversity of soil bacteria is due to different microhabitats present in that area from where soil samples were collected.

Preoperative oral fluoroquinolone antibiotics in elective colorectal surgery to prevent surgical site infections: a systematic review and meta-analysis.

Preoperative treatment with oral neomycin combined with erythromycin or metronidazole is recommended to decrease the risk of surgical site infections (SSIs) in elective colorectal surgery. However, oral neomycin is not commercially available in Canada, and therefore it is not routinely used. Fluoroquinolones are widely available and have excellent activity against aerobic Gram-negative bacteria. The aim of this systematic review was to identify, critically appraise and summarize the evidence on the efficacy and safety of preoperative use of oral fluoroquinolone antibiotics for the prevention of SSIs in adult patients undergoing elective colorectal resection. Following Cochrane guidelines, we included English-language randomized controlled trials (RCTs) comparing oral fluoroquinolones plus routine preoperative intravenous antibiotics against intravenous antibiotics alone from MEDLINE (Ovid), Embase (Ovid), the Cochrane Central Register of Controlled Trials( Ovid) and ClinicalTrials.gov. We included 3 RCTs (1136 patients). Risk of bias was uncertain in 2 trials and high in 1 trial. Preoperative oral fluoroquinolones led to significantly decreased total SSIs (risk ratio [RR] 0.43, 95% confidence interval [CI] 0.32-0.57, I 2 = 0%), superficial incisional (RR 0.38, 95% CI 0.22-0.68, I 2 = 32%), deep incisional (RR 0.19, 95% CI 0.06-0.65, I 2 = 0%) and organ/space SSIs (RR 0.34, 95% CI 0.12-0.90, I 2 = 33%). There was also a significant reduction in anastomotic leaks (RR 0.22, 95% CI 0.06-0.87, I 2 = 0%). No antibiotic-related adverse events were reported. This review suggests that preoperative oral fluoroquinolones with intravenous antibiotics are superior to intravenous antibiotics alone for preventing SSIs after colorectal surgery. If neomycin is unavailable, oral fluoroquinolones should be considered as a reasonable alternative. Future trials are required to further compare the relative efficacy of oral antibiotic regimens.

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.

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).

Clinical experience of cefiderocol.

Infections by antibiotic-resistant microorganisms could be considered a "stealth pandemic" that we fight daily in most hospitals. Some estimates suggest that today 700,000 deaths per year can be attributed to antimicrobial resistance. By the year 2050, it is estimated that this will increase to ten million deaths per year as a result of infections by multidrug-resistant microorganisms. In this context, the availability of antimicrobial therapy that is effective against these pathogens is essential to be able to "save the lives" of our patients. Cefiderocol, a new cephalosporin with a different mechanism of action, will be an essential treatment in many infections caused by resistant aerobic gram-negative bacteria. Cefiderocol has been used to treat patients with complicated urinary tract infections (cUTI); hospital-acquired pneumonia (HAP), ventilator-associated pneumonia (VAP), healthcare-associated pneumonia (HAP); in patients with sepsis and bacteremia, some without an identified primary focus of infection.