AIMS Microbiology最新文献

Infections caused by bacteria originating from tainted food sources are a widespread concern due to their large economic impact and detrimental effects on public health. We aimed to explore literature focusing on the presence of Salmonella in the food supply chains of Gulf Cooperation Council (GCC) countries and to provide an overview of available information concerning health-related issues and the status of salmonellosis in humans in GCC countries. The reviewed evidence underscored a gap in our comprehensive understanding of the prevalence of Salmonella in the food supply of GCC countries. Molecular characterization efforts to pinpoint the sources of Salmonella in these nations were limited. Surveys targeting Salmonella in the food supply of GCC countries have been infrequent. While qualitative data indicated the presence or absence of Salmonella, there was a noticeable lack of quantitative data detailing the actual quantities of these bacteria in chicken meat supplies across GCC countries. Although reports regarding Salmonella in animal-derived foods were common, the literature highlighted in this review emphasized the persistent challenge that Salmonella pose to food safety and public health in GCC countries. Addressing this issue requires concerted efforts to enhance surveillance, improve control measures, and promote greater awareness among stakeholders in the food supply chain.

In this study, we used 16S rRNA gene sequence analysis to describe the diversity of cultivable endophytic bacteria associated with fennel (Foeniculum vulgare Mill.) and determined their plant-beneficial traits. The bacterial isolates from the roots of fennel belonged to four phyla: Firmicutes (BRN1 and BRN3), Proteobacteria (BRN5, BRN6, and BRN7), Gammaproteobacteria (BRN2), and Actinobacteria (BRN4). The bacterial isolates from the shoot of fennel represented the phyla Proteobacteria (BSN1, BSN2, BSN3, BSN5, BSN6, BSN7, and BSN8), Firmicutes (BSN4, BRN1, and BRN3), and Actinobacteria (BRN4). The bacterial species Bacillus megaterium, Bacillus aryabhattai, and Brevibacterium frigoritolerans were found both in the roots and shoots of fennel. The bacterial isolates were found to produce siderophores, HCN, and indole-3-acetic acid (IAA), as well as hydrolytic enzymes such as chitinase, protease, glucanase, and lipase. Seven bacterial isolates showed antagonistic activity against Fusarium culmorum, Fusarium solani, and Rhizoctonia. solani. Our findings show that medicinal plants with antibacterial activity may serve as a source for the selection of microorganisms that exhibit antagonistic activity against plant fungal infections and may be considered as a viable option for the management of fungal diseases. They can also serve as an active part of biopreparation, improving plant growth.

Here, phytoremediation studies of toxic metal and organic compounds using plants augmented with plant growth-promoting bacteria, published in the past few years, were summarized and reviewed. These studies complemented and extended the many earlier studies in this area of research. The studies summarized here employed a wide range of non-agricultural plants including various grasses indigenous to regions of the world. The plant growth-promoting bacteria used a range of different known mechanisms to promote plant growth in the presence of metallic and/or organic toxicants and thereby improve the phytoremediation ability of most plants. Both rhizosphere and endophyte PGPB strains have been found to be effective within various phytoremediation schemes. Consortia consisting of several PGPB were often more effective than individual PGPB in assisting phytoremediation in the presence of metallic and/or organic environmental contaminants.

The oral microbiome represents an essential component of the oral ecosystem whose symbiotic relationship contributes to health maintenance. The biofilm represents a state of living of microorganisms surrounding themselves with a complex and tridimensional organized polymeric support and defense matrix. The substrates where the oral biofilm adhere can suffer from damages due to the microbial community metabolisms. Therefore, microbial biofilm represents the main etiological factor of the two pathologies of dental interest with the highest incidence, such as carious pathology and periodontal pathology. The study, analysis, and understanding of the characteristics of the biofilm, starting from the macroscopic structure up to the microscopic architecture, appear essential. This review examined the morphological methods used through the years to identify species, adhesion mechanisms that contribute to biofilm formation and stability, and how the action of microbicidal molecules is effective against pathological biofilm. Microscopy is the primary technique for the morphological characterization of biofilm. Light microscopy, which includes the stereomicroscope and confocal laser microscopy (CLSM), allows the visualization of microbial communities in their natural state, providing valuable information on the spatial arrangement of different microorganisms within the biofilm and revealing microbial diversity in the biofilm matrix. The stereomicroscope provides a three-dimensional view of the sample, allowing detailed observation of the structure, thickness, morphology, and distribution of the various species in the biofilm while CLSM provides information on its three-dimensional architecture, microbial composition, and dynamic development. Electron microscopy, scanning (SEM) or transmission (TEM), allows the high-resolution investigation of the architecture of the biofilm, analyzing the bacterial population, the extracellular polymeric matrix (EPS), and the mechanisms of the physical and chemical forces that contribute to the adhesion of the biofilm to the substrates, on a nanometric scale. More advanced microscopic methodologies, such as scanning transmission electron microscopy (STEM), high-resolution transmission electron microscopy (HR-TEM), and correlative microscopy, have enabled the evaluation of antibacterial treatments, due to the potential to reveal the efficacy of different molecules in breaking down the biofilm. In conclusion, evidence based on scientific literature shows that established microscopic methods represent the most common tools used to characterize biofilm and its morphology in oral microbiology. Further protocols and studies on the application of advanced microscopic techniques are needed to obtain precise details on the microbiological and pathological aspects of oral biofilm.

Transcriptomic and proteomic analysis were performed on 72 h biofilms of the acneic strain Cutibacterium acnes and planktonic cultures in the presence of epinephrine. Epinephrine predominantly downregulated genes associated with various transporter proteins. No correlation was found between proteomic and transcriptomic profiles. In control samples, the expression of 51 proteins differed between planktonic cultures and biofilms. Addition of 5 nM epinephrine reduced this number, and in the presence of 5 µM epinephrine, the difference in proteomic profiles between planktonic cultures and biofilms disappeared. According to the proteomic profiling, epinephrine itself was more effective in the case of C. acnes biofilms and potentially affected the tricarboxylic acid cycle (as well as alpha-ketoglutarate decarboxylase Kgd), biotin synthesis, cell division, and transport of different compounds in C. acnes cells. These findings are consistent with recent research on Micrococcus luteus, suggesting that the effects of epinephrine on actinobacteria may be universal.

Background: Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae including Escherichia coli (E. coli), are recognized as a global public health threat due to their multidrug-resistant (MDR) phenotypes and their rapid dissemination in aquatic environments. Nevertheless, studies investigating the prevalence and antimicrobial resistance (AMR) profile of ESBL-producing E. coli in Lebanese surface water are limited.

Objective: This study aimed to assess the physicochemical properties and microbial contamination load and to determine the distribution of AMR patterns of ESBL-producing E. coli in surface water samples from different sites in the North Governorate of Lebanon.

Methods: Water samples were collected from 25 major sites in North Lebanon. These samples were analyzed for the presence of total coliforms, E. coli, and fecal enterococci. Phenotypic and genetic characterizations were then performed for E. coli isolates to determine their resistance patterns and phylogenetic groups.

Results: Fifty-six samples out of 100 samples were positive for ESBL-producing E. coli, mostly harboring bla_CTX-M (40/56, 71%) including bla_CTX-M-15 (33/40, 82%), bla_TEM gene (36/56, 64%), bla_SHV (20/56, 36%), and bla_OXA (16/56, 29%) including bla_OXA-48 gene (11/16, 69%). Most ESBL-producing E. coli isolates belonged to the extra-intestinal pathogenic phylogroup B2 (40/56, 71.4%) while 10/56 (17.9%) belonged to the commensal phylogroup A.

Conclusion: Our results highlight the need to implement effective water monitoring strategies to control transmission of ESBL-producing E. coli in surface water and thus reduce the burden on human and animal health.

The food and beverage packaging industry has experienced remarkable growth in recent years. Particularly the requirement for appropriate packaging materials used for the sale of fermented products is boosted due to the rising acceptance of economical functional foods available to consumers on the shelves of their local supermarkets. The most popular nutraceutical foods with increased sales include natural yogurts, probiotic-rich milk, kefir, and other fermented food and beverage products. These items have mainly been produced from dairy-based or non-dairy raw materials to provide several product options for most consumers, including vegan and lactose-intolerant populations. Therefore, there is a need for an evaluation of the potential developments and prospects that characterize the growth of the food packaging industry in the global market. The article is based on a review of information from published research, encompassing current trends, emerging technologies, challenges, innovations, and sustainability initiatives for food industry packaging.

Presently, most of the reported infections are of a bacterial origin; however, this leads to a limit within the literature and research around infections caused by fungal pathogens, which are now developing resistance to antibiotic medicines. Of the natural antimicrobial agents, honey has been observed with demonstrable and highly exploitable antimicrobial and infection control related to wound healing properties; therefore, it has been incorporated into many standard pharmaceutical formulations. Generally, these products utilize a pure sample of honey as a bioactive ingredient in a product which has been purposely designed for the convenience of application. This article aims to review information available from published reports on various bioactivities of a variety of medical-grade honey products, including manuka and other conventional non-manuka types sourced from different floral types and geographical regions. Additionally, this review highlights the antibiotic activities of various types of honey products tested against pathogenic strains of bacteria, yeast and fungi, and their applications in the formulation of healthcare products.

The microbial community of the human large intestine mainly ferments dietary fiber to short chain fatty acids (SCFAs), which are efficiently absorbed by the host. The three major SCFAs (acetate, propionate, and butyrate) have different fates within the body and different effects on health. A recent analysis of 10 human volunteer studies established that the proportions of these SCFA in fecal samples significantly shifted towards butyrate as the overall concentration of SCFA increased. Butyrate plays a key role in gut health and is preferentially utilized as an energy source by the colonic epithelium. Here we discuss possible mechanisms that underlie this 'butyrate shift'; these include the selection for butyrate-producing bacteria within the microbiota by certain types of fiber, and the possibility of additional butyrate formation from lactate and acetate by metabolite cross-feeding. However, a crucial factor appears to be the pH in the proximal colon, which decreases as the SCFA concentrations increase. A mildly acidic pH has been shown to have an important impact on microbial competition and on the stoichiometry of butyrate production. Understanding these complex interactions has been greatly aided by the refinement of theoretical models of the colonic microbiota that assume a small number (10) of microbial functional groups (MFGs).

Multidrug-resistant tuberculosis (TB) (MDR-TB), or TB that is simultaneously resistant to both isoniazid (INH) and rifampicin (RIF), is a barrier to successful TB control and treatment. Stratified data on MDR-TB, particularly in the high-burden western Kenya region, remain unknown. This data is important to monitor the efficacy of TB control and treatment efforts. Herein, we determined the molecular epidemiology of drug-resistant TB and associated risk factors in western Kenya. This was a non-experimental, population-based, cross-sectional study conducted between January and August 2018. Morning sputum samples of individuals suspected of pulmonary TB were collected, processed, and screened for Mycobacterium tuberculosis (Mtb) and drug resistance using line probe assay (LPA) and Mycobacterium growth indicator tubes (MGIT) culture. MGIT-positive samples were cultured on brain heart infusion (BHII) agar media, and the presence of Mtb was validated using Immunochromatographic assay (ICA). Drug sensitivity was performed on MGIT and ICA-positive but BHI-negative samples. Statistical significance was set at P < 0.05. Of the 622 Mtb isolates, 536 (86.2%) were susceptible to RIF and INH. The rest, 86 (13.83%), were resistant to either drugs or both. A two-sample proportional equality test revealed that the MDR-TB prevalence in western Kenya (5%) did not vary significantly from the global MDR-TB estimate (3.9%) (P = 0.196). Men comprised the majority of susceptible and resistant TB (75.9% and 77.4%%, respectively). Also, compared with healthy individuals, the prevalence of HIV was significantly higher in MDR-TB patients (35.9% vs 5.6%). Finally, TB prevalence was highest in individuals aged 25-44 years, who accounted for 58.4% of the total TB cases. Evidently, the prevalence of MDRTB in western Kenya is high. Particular attention should be paid to men, young adults, and those with HIV, who bear the greatest burden of resistant TB. Overall, there is a need to refine TB control and treatment programs in the region to yield better outcomes.