Characteristics of antibiotic resistance mechanisms and genes of Klebsiella pneumoniae

Identification of proteotoxic and proteoprotective bacteria that non-specifically affect proteins associated with neurodegenerative diseases

There are no cures for neurodegenerative protein conformational diseases (PCDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). Emerging evidence suggests the gut microbiota plays a role in their pathogenesis, though the influences of specific bacteria on disease-associated proteins remain elusive. Here, we reveal the effects of 229 human bacterial isolates on the aggregation and toxicity of Aβ1-42, α-synuclein, and polyglutamine tracts in Caenorhabditis elegans expressing these culprit proteins. Our findings demonstrate that bacterial effects on host protein aggregation are consistent across different culprit proteins, suggesting that microbes affect protein stability by modulating host proteostasis rather than selectively targeting disease-associated proteins. Furthermore, we found that feeding C. elegans proteoprotective Prevotella corporis activates the heat shock response, revealing an unexpected discovery of a microbial influence on host proteostasis. Insight into how individual bacteria affect PCD proteins could open new strategies for prevention and treatment by altering the abundance of microbes.

Prevalence and antimicrobial susceptibility pattern of Klebsiella pneumoniae isolated from various clinical specimens at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

K. pneumoniae become multidrug-resistant (MDR) and commonly poses a serious health threat to patients due to limited therapeutic options. As a result, determining the prevalence and antimicrobial susceptibility patterns of K. pneumoniae isolates from clinical specimens is substantial to patient diagnosis and treatment.

METHODS AND MATERIALS

A retrospective cross-sectional study was conducted from July 2021 to July 2022 at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. Sociodemographic and laboratory data were collected from registered books using a data collection sheet. All types of samples were collected and processed using standard procedures. Identification of K. pneumoniae was done using Gram stain, colony characterization on culture media, anda series of biochemical tests. Antimicrobial susceptibility testing was done by the Kirby Bauer disc diffusion technique. The data were entered using Epi-info version 7 and exported to SPSS version 20 for analysis.

RESULTS

Among 2600 clinical specimens, 735 (28.3%) were positive for bacteria, and K. pneumoniae isolates accounted for 147 (20%). Most of them were isolated from neonates and mainly obtained from blood specimens (81.6%). These isolates were 100% resistant to Nalidixic acid, Cefotaxime, and Cefazolin. About 84% and 83.3% of the isolates were also resistant to Ceftriaxone and Tetracycline, respectively. However, they are sensitive to Nitrofurantoin (86.6%), Imipenem (85.7%), Meropenem (79%), and Amikacin (78.3%). The overall proportion of MDR K. pneumoniae isolates accounted for 57.1%.

CONCLUSION

The magnitude of MDR K. pneumoniae was very alarming. Therefore, strengthening antimicrobial stewardship programs and antimicrobial surveillance practices is strongly recommended in the study area.

Development and Evaluation of the Biological Activities of a Plain Mucoadhesive Hydrogel as a Potential Vehicle for Oral Mucosal Drug Delivery

This study aimed to develop HGs based on cationic guar gum (CGG), polyethylene glycol (PEG), propylene glycol (PG), and citric acid (CA) using a 2k factorial experimental design to optimize their properties. HGs were characterized through FTIR and Raman spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The biological activities of HGs were determined by evaluating their mucoadhesive capacity and antibacterial activity in vitro, whereas their toxicity was analyzed using Artemia salina nauplii as an in vivo model. Results revealed that HGs were successfully optimized for their viscosity, pH, and sensory properties, and it was observed that varying concentrations of PEG-75 did not influence them. Through SEM analyses, it was noted that increased levels of PEG-75 resulted in HGs with distinct porosity and textures, whereas FTIR and Raman spectroscopy exhibited representative peaks of the raw materials used during the synthesis process. TGA studies indicated the thermal stability of HGs, as they presented degradation patterns at 100 and 300 °C. The synthesized HGs exhibited similar mucoadhesion kinetic profiles, demonstrating a displacement factor at an equilibrium of 0.57 mm/mg at 5 min. The antibacterial activity of HGs was appraised as poor against Gram-positive and Gram-negative bacteria due to their MIC90 values (>500 μg/mL). Regarding A. salina, treatment with HGs neither decreased their viability nor induced morphological changes. The obtained results suggest the suitability of CGG/PEG HGs for oral mucosa drug delivery and expand the knowledge about their mucoadhesive capacity, antibacterial potential, and in vivo biocompatibility.

Prevalence and Antibiotic Resistance of Klebsiella pneumoniae in Diabetic Foot Ulcer

Introduction A serious global threat of antimicrobial resistance has emerged due to the improper use of antibiotics, including polypharmacy and inappropriate prescribing. This misuse has led bacteria to develop immunity against these drugs. Klebsiella pneumoniae, a concerning gram-negative bacterium, has become resistant, especially among immunocompromised diabetic patients for multiple antibiotics. To fight effectively this growing crisis and regain control of these infections, it is crucial to comprehend the resistance mechanisms utilized by the bacteria and develop a new therapeutic strategy to prevent antibiotic resistance. Materials and methods A five-month study from January 2023 to May 2023 was conducted at the tertiary healthcare facility of Saveetha Medical College by collecting 122 clinical specimens from patients with diabetic foot ulcers (DFUs) and ulcer-related infections. The microbiological testing methods followed by the identification of bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and antimicrobial susceptibility testing (AST) by the VITEK 2 Compact system were performed. Results A stout, rod-shaped, gram-negative bacilli was observed in gram staining, and growth of mucoid γ-hemolytic colonies and lactose-fermenting mucoid colonies were seen in blood and MacConkey agar plates. MALDI-TOF analysis confirmed the presence of Klebsiella pneumoniae along with other bacteria such as Klebsiella oxytoca, Staphylococcus spp., Proteus spp., and ​​Escherichia ​coli. VITEK showed high resistance rates to commonly used antibiotics, including carbapenems. Notably, isolates showed sensitivity and intermediate to tigecycline and colistin. Resistance patterns varied across specimen types, emphasizing the importance of considering clinical sources when interpreting data. Conclusion Hence, this study underscores the urgent need for novel antimicrobial agents and effective infection control measures to combat multidrug-resistant Klebsiella pneumoniae infections. Understanding resistance mechanisms is essential for the incorporation of treatment strategies and preserving antibiotic efficacy.

Two weeks of acarbose treatment shows no effect on gut microbiome composition in patients with type 2 diabetes: a randomised, placebo-controlled, double-blind, crossover study

Aim

The alpha-glucosidase inhibitor acarbose is approved for the treatment of type 2 diabetes (T2D). It acts in the lumen of the gut by reducing intestinal hydrolysis and absorption of ingested carbohydrates. This reduces postprandial blood glucose concentration and increases the content of carbohydrates in the distal parts of the intestine potentially influencing gut microbiome (GM) composition and possibly impacting the gut microbiome (GM) dysbiosis associated with T2D. Here, we investigated the effect of acarbose on GM composition in patients with T2D.

Methods

Faecal samples were collected in a previously conducted randomised, placebo-controlled, double-blind, crossover study in which 15 individuals with metformin-treated T2D (age 57-85 years, HbA1c 40-74 mmol/mol, BMI 23.6-34.6 kg/m2) were subjected to two 14-day treatment periods with acarbose and placebo, respectively, separated by a 6-week wash-out period. Faecal samples were collected before and by the end of each treatment period. The GM profiles were evaluated by 16S rRNA gene amplicon sequencing.

Results

The GM profiles after the treatment periods with acarbose or placebo remained unaffected (P > 0.7) when compared with the GM profiles before treatment. This applied to the analysis of within-sample diversity (α-diversity) and between-sample bacterial composition diversity (β-diversity). Additionally, no dominant bacterial species differentiated the treatment groups, and only minor increases in the relative abundances of Klebsiella spp. and Escherichia coli (P < 0.05) were observed after acarbose treatment.

Conclusion

In patients with metformin-treated T2D, 14 days of treatment with acarbose showed only minor effects on GM as seen in increased relative abundances of Klebsiella spp. and Escherichia coli.

Exploring the biotechnological potential of novel soil-derived Klebsiella sp. and Chryseobacterium sp. strains using phytate as sole carbon source

Phosphorus (P) is essential for biological systems, playing a pivotal role in energy metabolism and forming crucial structural components of DNA and RNA. Yet its bioavailable forms are scarce. Phytate, a major form of stored phosphorus in cereals and soils, is poorly bioavailable due to its complex structure. Phytases, enzymes that hydrolyze phytate to release useable phosphorus, are vital in overcoming this limitation and have significant biotechnological applications. This study employed novel method to isolate and characterize bacterial strains capable of metabolizing phytate as the sole carbon and phosphorus source from the Andes mountains soils. Ten strains from the genera Klebsiella and Chryseobacterium were isolated, with Chryseobacterium sp. CP-77 and Klebsiella pneumoniae CP-84 showing specific activities of 3.5 ± 0.4 nkat/mg and 40.8 ± 5 nkat/mg, respectively. Genomic sequencing revealed significant genetic diversity, suggesting CP-77 may represent a novel Chryseobacterium species. A fosmid library screening identified several phytase genes, including a 3-phytase in CP-77 and a glucose 1-phosphatase and 3-phytase in CP-84. Phylogenetic analysis confirmed the novelty of these enzymes. These findings highlight the potential of phytase-producing bacteria in sustainable agriculture by enhancing phosphorus bioavailability, reducing reliance on synthetic fertilizers, and contributing to environmental management. This study expands our biotechnological toolkit for microbial phosphorus management and underscores the importance of exploring poorly characterized environments for novel microbial functions. The integration of direct cultivation with metagenomic screening offers robust approaches for discovering microbial biocatalysts, promoting sustainable agricultural practices, and advancing environmental conservation.

Relevance of the Adjuvant Effect between Cellular Homeostasis and Resistance to Antibiotics in Gram-Negative Bacteria with Pathogenic Capacity: A Study of Klebsiella pneumoniae

Antibiotic resistance has become a global issue. The most significant risk is the acquisition of these mechanisms by pathogenic bacteria, which can have a severe clinical impact and pose a public health risk. This problem assumes that bacterial fitness is a constant phenomenon and should be approached from an evolutionary perspective to develop the most appropriate and effective strategies to contain the emergence of strains with pathogenic potential. Resistance mechanisms can be understood as adaptive processes to stressful conditions. This review examines the relevance of homeostatic regulatory mechanisms in antimicrobial resistance mechanisms. We focus on the interactions in the cellular physiology of pathogenic bacteria, particularly Gram-negative bacteria, and specifically Klebsiella pneumoniae. From a clinical research perspective, understanding these interactions is crucial for comprehensively understanding the phenomenon of resistance and developing more effective drugs and treatments to limit or attenuate bacterial sepsis, since the most conserved adjuvant phenomena in bacterial physiology has turned out to be more optimized and, therefore, more susceptible to alterations due to pharmacological action.

Mechanisms of Antibiotic Resistance and Developments in Therapeutic Strategies to Combat Klebsiella pneumoniae Infection

Infections with drug-resistant bacteria have become one of the greatest public health challenges, and K. pneumoniae is among the top six drug-resistant bacteria. K. pneumoniae often causes nosocomial infections, leading to illnesses such as pneumonia, liver abscesses, soft tissue infections, urinary tract infections, bacteremia, and in some cases death. As the pathogen continues to evolve and its multidrug resistance increases, K. pneumoniae poses a direct threat to humans. Drug resistance in K. pneumoniae may occur due to the formation of biofilms, efflux pumps, and the production of β-lactamases. In many cases, resistance is further enhanced by enzymatic modification and loss of porins. Drug resistance to K. pneumoniae has led to a decline in the effectiveness of conventional therapies against this pathogen. Therefore, there is an urgent need to accelerate the development of new antibiotics and explore new therapeutic approaches such as antimicrobial peptides, phages, traditional Chinese medicine, immunotherapy, Antimicrobial nanoparticle technology, antisense oligonucleotides and gene editing technologies. In this review, we discuss the mechanisms of drug resistance in K. pneumoniae and compare several new potential therapeutic strategies to overcome drug resistance in the treatment of K. pneumoniae infections.

Insights into the preventive actions of natural compounds against Klebsiella pneumoniae infections and drug resistance

Klebsiella pneumoniae is a type of Gram-negative bacteria that causes a variety of infections, including pneumonia, bloodstream infections, wound infections, and meningitis. The treatment of K. pneumoniae infection depends on the type of infection and the severity of the symptoms. Antibiotics are generally used to treat K. pneumoniae infections. However, some strains of K. pneumoniae have become resistant to antibiotics. This comprehensive review examines the potential of natural compounds as effective strategies against K. pneumonia infections. The alarming rise in antibiotic resistance underscores the urgent need for alternative therapies. This article represents current research on the effects of diverse natural compounds, highlighting their anti-microbial and antibiofilm properties against K. pneumonia. Notably, compounds such as andrographolide, artemisinin, baicalin, berberine, curcumin, epigallocatechin gallate, eugenol, mangiferin, piperine, quercetin, resveratrol, and thymol have been extensively investigated. These compounds exhibit multifaceted mechanisms, including disruption of bacterial biofilms, interference with virulence factors, and augmentation of antibiotic effectiveness. Mechanistic insights into their actions include membrane perturbation, oxidative stress induction, and altered gene expression. While promising, challenges such as limited bioavailability and varied efficacy across bacterial strains are addressed. This review further discusses the potential of natural compounds as better alternatives in combating K. pneumonia infection and emphasizes the need for continued research to harness their full therapeutic potential. As antibiotic resistance persists, these natural compounds offer a promising avenue in the fight against K. pneumonia and other multidrug-resistant pathogens.

Interactions and Implications of Klebsiella pneumoniae with Human Immune Responses and Metabolic Pathways: A Comprehensive Review

Klebsiella pneumoniae (K. pneumoniae), a significant contributor to the global challenge of antibiotic resistance, is not only a ubiquitous component of the human microbiome but also a potent pathogen capable of causing a spectrum of diseases. This review provides a thorough analysis of the intricate interactions between K. pneumoniae and the human immune system, elucidating its substantial impact on metabolic processes. We explore the mechanisms employed by K. pneumoniae to evade and manipulate immune responses, including molecular mimicry, immune modulation, and biofilm formation. The review further investigates the bacterium's influence on metabolic pathways, particularly glycolysis, highlighting how these interactions exacerbate disease severity. The emergence of multidrug-resistant and extremely drug-resistant strains within the Enterobacteriaceae family has heightened the public health crisis, underscoring the urgency for comprehensive research. We investigate the roles of the host's complement system, autophagy, cell death mechanisms, and various cytokines in combating K. pneumoniae infections, shedding light on areas that warrant further academic investigation. Additionally, the review discusses the challenges posed by K1- and K2-capsule polysaccharides in vaccine development due to their complex molecular structures and adhesive properties. Acknowledging the limited availability of effective antimicrobials, this review advocates for exploring alternative approaches such as immunotherapeutics, vaccinations, and phage therapy. We consolidate current knowledge on K. pneumoniae, covering classical and non-classical subtypes, antimicrobial resistance-mediated genes, virulence factors, and epidemiological trends in isolation and antibiotic resistance rates. This comprehensive review not only advances our understanding of K. pneumoniae but also underscores the imperative for ongoing research and collaborative efforts to develop new prevention and treatment strategies against this formidable pathogen.