International Journal of Microbiology最新文献

Plastics are used widely in almost every field of life, but their synthetic and persistent nature makes them harmful for the environment. The aim of this research was to evaluate the degradation abilities of Aspergillus niger, Candida albicans, and Acremonium sclerotigenum on microplastics (MPs). MP pieces of 4 ± 1 mm, including polyethylene, polyethylene terephthalate, and polystyrene, were incubated with fungal inoculums for 30 days. The degradation of treated MPs was determined by biofilm formation, weight loss, scanning electron microscopy (SEM), and Fourier transform analyses. The results indicated that the polyethylene MPs treated with Aspergillus niger exhibited the highest level of biofilm formation (optical density 1.595) and percentage weight loss (16%). In the case of polyethylene terephthalate and polystyrene MPs, Acremonium sclerotigenum and co-culture showed weight loss of 6% and 10%, respectively. Candida albicans was observed to be the least effective in biodegradation analyses. SEM observation revealed the surface modifications as holes, pits, cracks, and increased roughness in treated MPs. Fourier transform infrared (FTIR) spectroscopy showed that the chemical structure of each polymer exhibited some variations. The study concluded that the fungal strains play an important role in the biodegradation of plastics and can be utilized to mitigate environmental pollution.

Toxigenic fungi are capable of producing toxic metabolites, called mycotoxins. But the presence of silent and lowly expressed genes represents the main challenge for the discovery of novel mycotoxins, especially their lesser-known forms, commonly referred to as "emerging mycotoxins." Epigenetic modifiers (EMs) are compounds that are able to alter the production of metabolites through the induction of silent biosynthetic pathways leading to an enhanced chemical diversity. The aim of this study was to assess the effects of different chemical modulators on the metabolic profiles of the well-known toxigenic fungal species, Fusarium verticillioides. Four EMs, 5-azacytidine, sodium butyrate, nicotinamide (NIC), and sodium valproate (SV), were used. Following their addition to Fusarium verticillioides cultures, the metabolic profiles were analyzed by using UHPLC-HRMS/MS under targeted and untargeted metabolomics approaches. Metabolites were putatively annotated through the use of MS-DIAL and MS-FINDER. Our results show that the treatment with SV induced the most important alteration of the secondary metabolic profile of F. verticillioides, by promoting the expression of cryptic genes. Among the 50 most discriminating metabolites across five culture conditions, 12 were fusarins or fusarin analogs. In contrast, SB and NIC had little impact on these metabolites. The study highlights SV's ability to alter gene expression by inhibiting DNA deacetylation in fungal strains. This research could have significant implications for agriculture and food industry, especially in regions facing major mycotoxin challenges.

Aims/Introduction: Phage display method is a crucial tool to find novel clinically valuable diabetes-associated autoantigens and identify known autoantigen epitopes that are associated with diabetes and could provide scientific support and guidance for the artificial construction and synthesis of Type I diabetes mellitus (T1DM) novel biomarkers. Materials and Methods: The phage display system was used for the "biopanning" of T1DM serum. Following the sequencing of the phage DNAs, the homologous sequences of the above fusion heptapeptide were further investigated by BLAST to track the origin of the polypeptide sequences. The antibody spectrum revealed new T1DM-associated epitopes and antibodies. Results: A total of 1200 phage DNA were sequenced and 9 conserved polypeptide sequences were collected. It was confirmed that the zinc transporter and islet amyloid protease were among them. The conserved polypeptide sequence 8 and another three distinctive polypeptide sequences derived from Proteus were discovered. Furthermore, we expressed recombinant proteins with homologous polypeptide sequences for the human islet amyloid polypeptide (IAPP) and polypeptide precursor human zinc transporter 8 (ZNT8). Through clinical sample detection for the serum from T1DM (n = 100) and T2DM (n = 200) patients, results demonstrate the importance and relevance of these polypeptides in the recognition and classification of various forms of diabetes. Conclusion: Human pancreatic and concurrent bacterial-derived protein antigens and their epitopes were identified in this research by the phage display system, which is crucial for distinguishing different types of diabetes.

Aflatoxins, primary foodborne mycotoxins, come from Aspergillus flavus and Aspergillus parasiticus fungi. They pose significant health risks to humans and animals, creating a major challenge in the dairy sector. The objective of this study is to evaluate the knowledge, attitudes, and practices (KAP) of dairy farmers regarding aflatoxin contamination in milk and feeds. Conducted as a cross-sectional study in Bahir Dar city between November 2019 and February 2020, this investigation randomly selected 106 dairy farms for data collection. Face-to-face interviews, facilitated by a semistructured questionnaire, were employed. Findings indicate that 59.4% of respondents displayed good knowledge, while a substantial 94.3% exhibited a favorable attitude. Intriguingly, only 1.9% implemented good practices. Notably, the educational background of dairy farmers emerged as a significant factor influencing their KAP (p < 0.05). Conversely, various sociodemographic factors did not yield a significant impact on the KAP of dairy farmers. Despite a robust knowledge base and favorable attitudes towards aflatoxin among dairy farmers, the study highlights a significant gap in the implementation of recommended practices. This finding emphasizes the necessity for increased efforts to cultivate and reinforce good practices. Collaborative initiatives involving diverse stakeholders are crucial to reducing aflatoxin contamination in the dairy industry.

Vaginal infections are a public health problem associated with serious health complications due to the exacerbated inflammation they generate. Vaginal inflammation may also occur in some noninfectious processes, such as noninfectious vaginitis and cytolytic vaginosis. Immune system cells respond to infections through various mechanisms, such as the formation of extracellular traps (ETs), which are DNA networks associated with effector proteins. Many pathogens induce ETs formation in vitro, as occurs in some natural infections. A recent report indicates that human vaginal infections in vivo generate ETs. Therefore, in this study, we aimed to identify ETs in samples from 40 donors who were diagnosed with infectious (i.e., bacterial vaginosis, candidiasis and trichomoniasis) and noninfectious (i.e., noninfectious vaginitis and cytolytic vaginosis) vaginal inflammation. We were able to observe ETs by identifying the LL-37 peptide, which is associated with DNA networks. In seven vaginal swabs from the control group (formed by 19 donors without vaginal infection symptoms), we detected at least one pathogen per sample and observed ETs; thus, these donors were considered asymptomatic. The remaining 12 donors were confirmed to be healthy, as their exudates did not present any tested pathogens, sign of inflammation or ETs. ETs in vaginal inflammatory processes can worsen inflammation but may also help control infection.

The need to address antimicrobial resistance (AMR) through a One Health (OH) approach is now well recognized. There is, however, limited guidance on how AMR surveillance should be implemented across sectors to generate meaningful AMR and AMU data for decision-making. Using a sympatric approach to cross-sector sample collection, Nepal adopted the WHO extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) Tricycle Project as a step toward OH surveillance for assessing the prevalence of ESBL-producing E. coli across human, veterinary, and environment sectors. This involved a three-stage approach: identification of human hotspots (Stage 1) and sample collection sites for poultry (Stage 2) and wastewater (Stage 3). A total of 53 blood cultures from patients with bloodstream infections (BSIs), 100 stool samples from healthy pregnant women, 220 poultry ceca from slaughterhouses and live markets, and 48 wastewater samples were processed for bacterial culture and analyzed for the presence of ESBL-producing E. coli. The prevalence of ESBL-producing E. coli among isolated E. coli was the highest in wastewater samples (91%) followed by human BSIs (49%), poultry (38.6%), and fecal carriage isolates from healthy pregnant females (15%). A statistically significant association was seen in the prevalence of multidrug resistance among ESBL producers (52%) and nonproducers (26%). ESBL-producing E. coli was detected in all wastewater samples tested except for the upstream river. The findings of the study showed a high prevalence of ESBL-producing E. coli in samples from all three sectors and provided baseline data based upon which strategies for the safe disposal of communal and hospital waste, integrated AMR surveillance, and control strategies could be planned and implemented.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) several years ago highlighted the challenge of multidrug-resistant infections, emphasizing the critical need for innovative treatment approaches. Myrtenol, known for its antibacterial and antibiofilm properties, holds promise as a potential treatment option. This study aimed to evaluate the effectiveness of myrtenol against MRSA. The collected MRSA isolates were assessed for antimicrobial susceptibility following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2023. Biofilm formation by MRSA was evaluated using the tissue culture plate (TCP) technique. The minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal biofilm inhibitory concentration (MBIC) of myrtenol against MRSA were determined both individually and in combination with antibiotics. Real-time PCR was employed to investigate the impact of myrtenol on the expression of virulence genes (sarA, agrA, and icaD) across the isolates. In this study, MRSA was identified in 90 out of 400 cases (22.5%) of hospital-acquired pathogens. Among the collected MRSA isolates, 53 out of 90 (59%) were found to produce biofilms. The MIC of myrtenol was comparable to the MBC across all tested isolates, they were almost the same. Combinations of myrtenol with most tested antibiotics exhibited synergistic effects exceeding 60%. Among the 53 biofilm-producing isolates, 45 isolates (85%) expressed the sarA gene, 49% expressed the agrA gene, and all biofilm-producing MRSA isolates (100%) expressed the icaD gene. A notable reduction in the relative quantity (RQ) values of virulence gene expression was observed after treatment with the MBIC of myrtenol across all tested isolates. Myrtenol demonstrated strong antimicrobial activity against MRSA, notably reducing the expression of key virulence genes linked to biofilm formation. This suggests its potential as a therapeutic agent for treating biofilm-associated MRSA infections.

At a global scale, grains and poultry feeds are the primary sources of feed. Due to their considerable significance, any fungi capable of infecting these feedstuffs can pose a threat to both food safety and security. Fusarium spp. are a highly significant group of organisms. Fumonisins (FBs), deoxynivalenol (DON), trichothecene (T-2), and zearalenone (ZEN) are classifications of mycotoxins that are synthesized by Fusarium species. Their presence is associated with a range of factors that occur during growth, processing, and storage. We have recorded the high occurrence of Fusarium spp. in grains and poultry feeds in all tested samples. Fusarium (F) oxysporum was the most common species that appeared in all tested two hundred samples. FB1 was the predominant toxin that appeared with the highest concentration in 56 pellet samples with the range of 10.34-1043 μg/kg. Also, it occurred with levels of 4.67-956 μg/kg in the tested ingredients samples. Fusarium verticillioides isolates were the highest producers of FB1. Fusarium spp. isolates showed positive FB1 production with 84.6%, 82.5%, 82.2%, and 78.1%, isolated from pellet feed samples that were collected from Alhassa, Jeddah, Qassim, and Riyadh, respectively. 31.6%, 76.9%, 23.1%, 83.3%, and 88% of tested Fusarium spp. strains exhibited FB1 production in samples of barley, corn, sorghum, soybean, and wheat bran, respectively, with the range of 18-655 μg/kg. Genes responsible for FB1, DON, T-2, and ZEN production were detected in the Fusarium spp. isolates.

Stenotrophomonas maltophilia causes challenging infections in immunocompromised patients, exhibiting increasing resistance to multiple antimicrobials and possessing various virulence genes, including emerging resistance to trimethoprim-sulfamethoxazole. A total of 80 clinical isolates of S. maltophilia were collected from multiple hospitals in Tehran, Iran. This study conducted an analysis of antibiotic susceptibility by disc diffusion method and E-test assay, resistance and virulence gene frequencies were examined by PCR-sequencing, and multilocus sequencing typing (MLST) was performed for strain typing. Across the tested isolates, we observed notably high resistance rates for imipenem 80 (100%), meropenem 78(97.5%), and ceftazidime 72 (90%), while trimethoprim-sulfamethoxazole (SXT) showed a lower resistance rate of 2 (2.5%). Minocycline and levofloxacin demonstrated the highest susceptibility rates, with 70 (87.5%) and 80 (100%), respectively. The prevalence of antibiotic resistance genes bla _L1, and bla _L2 was 71 (88.75%) and 76 (95%), respectively. Additionally, the PCR analysis revealed that the frequency of virulence genes (fliC, virB, papD, pilU, hlyIII, stmPr1, and stmPr2) was 78 (97.5%), 77 (96.25%), 58 (72.5%), 77 (96.2%), 76 (95%), 31 (38.75%), and 80 (100%), respectively. Resistance to SXT isolate belong to the sequence type (ST15) and exhibits allelic profiles of (10, 29, 21, 21, 32, 32, and 10). The data obtained from our investigation have indicated that SXT remains an efficacious antibiotic and also highlighted the importance of effective management, identification of resistant isolates, and typing methods to address the global prevalence of antibiotic resistance in S. maltophilia.

COVID-19 serological tests complement the molecular diagnostics and can be used as important tool for serosurveillance and vaccine efficiency evaluation. The aim of this study was to develop and evaluate the diagnostic performance of an in-house ELISA for retrospective serosurveillance of SARS-CoV-2. Total IgG and IgM levels in sera of PCR positive SARS-CoV-2 patients (n = 50) from North Colombo Teaching Hospital were evaluated and compared with sera (n = 50) collected from prepandemic healthy individuals as controls. Patient sample collection was initiated before vaccination programme was widely started within the country. Seropositivity of 94.0% (n = 47/50) was observed for either IgG or IgM anti-SARS-CoV-2 antibodies against receptor binding domain of spike protein or nucleocapsid protein in confirmed cases while none of controls were seropositive. In contrast, the seropositivity of only 48.0% (n = 24/50) was demonstrated with commercial ELISA kits for detection of IgG or IgM. All samples detected seropositive by commercially available kits remained seropositive with either in-house IgM or IgG ELISA. Significant correlations (p ≤ 0.001) were observed between Ab levels and day of sampling from the onset of illness. The overall sensitivity values of the in-house assays were 66.7%, 96.9%, and 100.0% for the first, second, and third week or longer after onset of symptoms for either in-house IgM or IgG ELISAs. Majority of the patients (>80.0%) were seropositive, regardless of age (<60 vs. >60 years), gender (male vs. female), or clinical severity (mild vs. moderate/severe). These data suggest that the developed in-house ELISAs can be applied to assess anti-SARS-CoV-2 antibody levels induced by either natural infections or vaccination.