International Journal of Microbiology最新文献

Research into biologically natural substances with antitumor properties, known for their potential to induce fewer side effects and exhibit specificity toward cancerous cells, remains imperative. The pressing demand for novel agents in cancer therapy underscores the intensive investigation of natural products from microorganisms. Penicillium aurantiogriseum, frequently isolated from food and feed, emerges as a promising candidate against pathogenic bacteria and fungi. This species harbors numerous mycotoxins that warrant extensive clinical study due to their potential in cancer treatment. Identifying mycotoxins with anticancer properties produced by P. aurantiogriseum could unveil novel therapeutic targets and enrich the pharmacological landscape. This review provides a comprehensive overview of the utilization of P. aurantiogriseum mycotoxins in cancer research and elucidates therapeutic agents' advantages and limitations. P. aurantiogriseum produces at least 15 mycotoxins with potent anticancer effects mediated through diverse mechanisms, including enzyme inhibition (e.g., pseurotin), induction of apoptosis (e.g., auranthine, aurantiamides A, aurantiomides A-C, penicillic acid, penitrem, verrucisidinol, acetate verrucosidinol, and chaetoglobosin A), and cell-cycle arrest (e.g., anicequol, aurantiamine, and Taxol). Although certain mycotoxins, such as Taxol, Anacin, and Compactin, are used in commerce, many others remain relatively unexplored. The mycotoxins derived from P. aurantiogriseum hold considerable potential for cancer treatment, offering novel therapeutic avenues and enhancing current treatments through synergistic combinations and advanced delivery systems.

The World Health Organization (WHO) describes Shiga toxin-producing Escherichia coli (STEC) as a bacterium that can cause severe food-borne diseases. Common sources of infection include undercooked meat products and faecal contamination in vegetables. This study aimed to isolate, identify and assess the virulence and antibiotic resistance profiles of STEC isolates from broiler chicken faeces. Faecal samples were cultured, and polymerase chain reaction (PCR) was utilized to identify the isolates. Subsequently, the confirmed isolates were screened for seven virulence markers using PCR. The antibiotic susceptibility of the isolates to 13 different antibiotics was determined using the disk diffusion method. PCR was also employed to screen for antibiotic resistance genes. The uidA gene, which encodes the beta-glucuronidase enzyme, was detected in 62 (64.6%) of the 91 presumptively identified E. coli isolates. Of these, 23 isolates (37.1%) were confirmed to be E. coli O177 serogroup through amplification of wzy gene. All E. coli O177 isolates possessed the virulence stx2 gene, while 65% carried the stx1 gene. Among the E. coli O177 isolates, three harboured a combination of vir + stx2 + stx1 + hlyA genes, while one isolate contained a combination of eaeA + stx2 + stx1 + hlyA genes. All E. coli O177 isolates carried one or more antimicrobial resistance (AMR) genes, with 17 isolates (73.7%) identified as multidrug resistance (MDR). This is the first study to report the presence of E. coli O177 serotype from broiler chickens in South Africa. The findings reveal that broiler chicken faeces are a significant reservoir for MDR E. coli O177 and a potential source of AMR genes. These results underscore the importance of continuous surveillance and monitoring of the spread of AMR infectious bacteria in food-producing animals and their environments. The study also emphasizes that monitoring and control of poultry meat should be considered a major public health concern.

Dynamics of gut microbiota and their associations with the corresponding hematological injuries postradiation remain to be elucidated. Using single whole-body exposure to ⁶⁰Co-γ ray radiation at the sublethal dose of 2.5 Gy, we developed a beagle model of acute radiation syndrome (ARS) and then monitored the longitudinal changes of gut microbiome and hematology for 45 days. We found that the absolute counts of circulating lymphocytes, neutrophils, and platelets were sharply declined postradiation, accompanied by a largely shifted composition of gut microbiome that manifested as a significantly increased ratio of Firmicutes to Bacteroidetes. In irradiated beagles, alterations in hematological parameters reached a nadir on day 14, sustaining for 1 week, which were gradually returned to the normal levels thereafter. However, no structural recovery of gut microbiota was observed throughout the study. Fecal metagenomics revealed that irradiation increased the relative abundances of genus Streptococcus, species Lactobacillus animalis and Lactobacillus murinus, but decreased those of genera Prevotella and Bacteroides. Metagenomic functions prediction demonstrated that 26 altered KEGG pathways were significantly enriched on Day 14 and 35 postradiation. Furthermore, a total of 43 bacterial species were found to correlate well with hematological parameters by Spearman's analysis. Our results provide an insight into the longitudinal changes in intestinal microbiota at different clinical stages during ARS in canine. Several key microbes those tightly associated with the hematological alterations may serve as biomarkers to discriminate the different phases of host with ARS.

Food is the primary substance needed by humans to survive. However, food is easily contaminated by spoilage bacteria, which cause a decrease in quality and shelf life. Moreover, spoilage bacteria in food can be pathogenic, leading to foodborne disease that endangers human health. This issue has also driven the widespread use of synthetic preservatives, which have negative effects both in the short and long term. Biopreservation efforts utilizing bacteriocins produced by lactic acid bacteria offer an alternative solution to prevent spoilage and extend the shelf life of food. These bacteriocins are safe to use as they are produced by lactic acid bacteria that are approved for use in food. The application of various types of bacteriocins as biopreservatives has been widely conducted. Several other types of bacteriocins are continuously being researched and developed to ensure their safety and suitability for use as food biopreservatives. This article highlights bacteriocins, including their classification, general overview, mechanisms of action, differences from antibiotics, diversity, applications, prospects, and challenges as future food biopreservatives. Additionally, this article presents commercial bacteriocins, namely, nisin and pediocin, which are frequently used for food preservation.

Biofilm is a structurally-connected microbial community, covered by a self-produced polymeric matrix and adhered to biotic or abiotic surfaces. This study aimed to evaluate the occurrence of biofilm-producing antibiotic-resistant bacteria in water from distribution systems. Water samples were taken from 32 tanks across Ondo City and Akure metropolis, Nigeria. Information regarding the sanitation status of the tanks was gathered by observation and oral interviews. The physicochemical properties were determined using standard methods. Using the pour plate technique. Agars included serially diluted water samples were inoculated onto plate count agar, mannitol salt agar, Salmonella-Shigella agar, MacConkey agar, and cetrimide nutrient agar to assess total viable bacteria, Staphylococcus aureus, Salmonella and Shigella, coliforms, and Pseudomonas aeruginosa, respectively. Eosin-methylene blue agar was used to cultivate Escherichia coli and Enterobacter aerogenes. Pure isolates were characterised using API kits and assessed for antibiotic resistance and biofilm production employing the Kirby-Bauer and tissue culture plate techniques, respectively. The ages of the water tanks ranged from 1 to 25 years old; all tanks had cover-lids; 13 (40.63%) had water guards while 12 (37.5%) underwent water treatment. The physicochemical properties chiefly fell within WHO standards for drinking water. One hundred and eighty-seven isolates were obtained. S. aureus (15.51%) had the highest frequency while Salmonella enterica (3.2%) had the lowest frequency. Thirty-six percent of the isolates were strong biofilm producers, while 20.67% Gram-negative and 18.69% Gram-positive bacterial isolates were antibiotic-resistant. This study revealed a high occurrence of biofilm-forming bacteria and prevalence of antibiotic-resistant bacteria in water distribution systems, emphasizing the urgency of improving water quality for public health protection.

Type 2 diabetes mellitus (T2DM) patients are at increased risk of infections, such as malignant otitis externa and rhinocerebral mucormycosis, with the urinary tract being the most affected (for example, emphysematous pyelonephritis commonly caused by Escherichia coli). Hence, this study assessed the prevalence of bacteriuria and antibiogram patterns of bacteria isolates among T2DM patients visiting the Ejisu Government Hospital in the Ashanti Region, Ghana. In this cross-sectional study, 58 patients visiting the hospital for routine healthcare were conveniently recruited after obtaining informed consent. Data on sociodemographic characteristics and medical history were obtained using pretested structured questionnaires. Mid-stream urine was collected for bacteria isolation and identification using standard bacterial culture and biochemical tests. Bacteria cultures ≥ 10⁵ CFU/mL were considered significant bacteriuria. The antibiotic sensitivity patterns of the bacteria isolates were evaluated using the Kirby-Bauer disc diffusion method. Bacteriuria was recorded among 15.5% (9/58) of the patients, mainly those with no previous history (77.8%) and no symptoms (55.6%) of urinary tract infections (UTIs). E. coli (55.6%) and Klebsiella spp. (44.6%) were primarily isolated from the T2DM patients. All the bacteria isolates (E. coli and Klebsiella spp.) demonstrated the highest resistance to co-trimoxazole and tetracycline (55.6%) and a complete susceptibility to amikacin and levofloxacin (100%). However, 60% of the E. coli isolates and 25% of the Klebsiella isolates were multidrug resistant (MDR; resistant to at least one antibiotic agent in three or more antimicrobial categories). The study shows that T2DM patients have bacteria in their urine which are resistant to most common antibiotics, even among those with no history of UTIs; hence, routine bacterial culture and antibiotic sensitivity testing among T2DM patients is recommended for better patient management to reduce the co-morbidities of UTIs.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, posing significant challenges and economic burdens on healthcare systems. Gut microbiota metabolites have shown promise in cancer treatment, but the specific active metabolites and their key targets remain unclear. This study employed a network pharmacology-based approach to identify potent metabolites of gut microbiota and their key targets. Active metabolites produced by gut microbiota were retrieved using the database gutMGene, and targets associated with these metabolites were identified using the Swiss Target Prediction tool. HCC-related targets were obtained from the GeneCards database, and overlapping targets were selected through a Venn diagram tool. An integrated metabolites-target-pathway network was analyzed to identify active inhibitors against HCC, including p-cresol glucuronide, secoisolariciresinol, glycocholic acid, enterodiol, and citric acid. Molecular docking tests were performed to validate the findings and assess the binding affinity of the metabolites with their target proteins. The study identified AKT1, EGFR, ALB, and TNF genes as potential therapeutic targets against hepatic cancer. The metabolites, p-cresol glucuronide, secoisolariciresinol, glycocholic acid, enterodiol, and citric acid, exhibited significant binding affinity with their respective target proteins. The study also revealed multiple signaling pathways and biological processes associated with the metabolites, demonstrating their preventive effect against HCC. This research utilizes a network pharmacology-based approach to identify potent metabolites of gut microbiota and their key targets for the treatment of HCC. The findings were validated through molecular docking tests, providing a foundation for future studies on anti-HCC metabolites and their mechanisms of action. Furthermore, this study offers insights into the development of novel anti-HCC drugs utilizing gut microbiota metabolites.

Fibrinolytic agents are essential in treating thrombosis, playing a critical role in improving survival rates in cardiovascular diseases. Microbial fibrinolytic proteases have emerged as promising alternatives due to their affordability, specificity, lower toxicity, and reduced side effects. Consequently, the search for microorganisms capable of producing these enzymes has gained significant economic importance in the pharmaceutical industry. This study reports and characterizes a novel fibrinolytic enzyme produced by Penicillium citrinum CFAM 521, a strain isolated from the Amazon region. The enzyme was purified using a polyethylene glycol (PEG)-phosphate salt aqueous two-phase system (ATPS). The effects of PEG molecular weight, PEG concentration, and phosphate concentration on the protease partition coefficient (K) were evaluated through a 2² full factorial design. The enzyme exhibited both fibrinolytic and fibrinogenolytic activities. After partitioning in a two-phase system with 10% (w/w) PEG and 15% (w/w) sodium phosphate, the fibrinolytic proteases were predominantly retained in the salt-rich bottom phase (K = 0.33). The enzyme has a molecular weight of 34 kDa, with optimal pH and temperature at 9°C and 37°C, respectively. Inhibitory analysis confirmed that it is a serine protease, and its activity was enhanced by the addition of Mn²⁺. Notably, the enzyme exhibited no hemolytic activity. Therefore, P. citrinum CFAM 521 represents a novel source of fibrinolytic enzymes, highlighting its potential as an alternative for the development of thrombolytic agents.

The COVID-19 pandemic has intensified the issue of multidrug-resistant (MDR) infections, particularly in intensive care units (ICUs). This study documents the first known case of coinfection with two extensively drug-resistant (XDR) bacterial isolates in a critically ill patient with COVID-19 in Saudi Arabia. Both XDR isolates were recovered from blood and were resistant to all tested antimicrobial agents except colistin. Whole genome sequencing (WGS) revealed that the K. pneumoniae isolate KP-JZ107 had sequence type 11 (ST11) and core genome MLST (cgMLST 304742), while the A. baumannii isolate AB-JZ67 had ST2 and cgMLST 785. KP-JZ107 was found to possess the virulence plasmid KpVP-type-1, carbapenemase genes bla _NDM and bla _KPC , and numerous antimicrobial-resistant genes (ARGs). The AB-JZ67 isolate had several biofilm-related genes, including biofilm-associated protein (BAP), csuE, and pgaB, and multiple ARGs, including bla _ADC-25, bla _OXA-23, and bla _OXA-66. Our findings suggest that the coexistence of KP-JZ107 and AB-JZ67 isolates may indicate their widespread presence in ICUs, requiring comprehensive surveillance studies across all hospitals.