Search Results (176)

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in treated hospital wastewater effluents constitute a major environmental and public health concern. The aim of this study was to investigate the antibiotic resistance patterns of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa isolated from wastewater effluent at the Benjamin Mkapa Hospital (BMH) in Dodoma, Tanzania. These bacteria were selected to represent the most prevalent gram-negative bacteria found in hospital wastewater, and they have the potential to generate resistance and spread resistance genes to antibiotics. The wastewater BMH is treated in a Constructed Wetland (CW) planted with Typha latifolia before being released into the environment. The bacteria were isolated from wastewater effluent collected at the outlet of the CW. Isolated bacteria were analyzed for antibiotic resistance by disc diffusion method. Molecular identification of bacterial species was performed by using 16S rRNA. The results show that Klebsiella ssp. was the most common isolate detected, with a prevalence of 39.3%, followed by E. coli (27.9%) and Pseudomonas ssp. (18.0%). Klebsiella ssp. were more resistant than Pseudomonas ssp. for Tetracycline, Gentamycin, Ciprofloxacin, and Sulfamethoxazole. Pseudomonas ssp. were more resistant than Klebsiella ssp. for Ceftriaxone and Azithromycin. Klebsiella ssp. harbored more resistance genes (40%), followed by Pseudomonas ssp. (35%) and E. coli (20%). The findings of this investigation indicate that the effluent from the CW requires additional treatment to reduce discharged ARB and ARGs in the receiving water bodies. As a result, the effluent quality of the CW should be continuously monitored and assessed, and further developments for treating the final effluent are necessary. Full article

Replant syndrome (RS) of fruit and nut trees causes reduced tree vigor and crop productivity in orchard systems due to repeated plantings of closely related tree species. Although RS etiology has not been clearly defined, the causal agents are thought to be a complex of soil microorganisms combined with abiotic factors and susceptible tree genetics. Different soil disinfection techniques alleviate RS symptoms by reducing the loads of the deleterious microbiome; however, the positive effect on crop growth is temporary. The goals of this paper are: (1) to conceptualize the establishment of the syndrome from a microbiome perspective and (2) to propose sustainable solutions to develop a beneficial microbiome to inhibit the onset of RS. Full article

This study examined whether the presence/absence of biofilm-associated genes may indicate the potential for differences in the biofilm formation among the Salmonella species/subspecies. We conducted an in vitro study on the biofilm formation by eighteen Salmonella strains of different species/subspecies. Strains belonging to subspecies enterica were generally poorer biofilm formers than strains belonging to species bongori and subspecies arizonae, diarizonae, and indica. A broader in silico study was subsequently conducted. The presence/absence of 57 biofilm-associated genes was further investigated among 323 Salmonella whole genomes of various species/subspecies. The lpfE gene was present in in 88.2% of subspecies enterica but was absent in ~90.2–100% of other subspecies. The sirA gene was present in 11.8% of subspecies enterica and 2.9% of S. diarizonae genomes while absent in other species/subspecies. The lpfe gene and sirA gene in subspecies enterica negatively correlated with environmental biofilm formation. The csrB gene was present in 71.4% of the S. arizonae and 94.3% of S. diarizonae genomes but absent in other species/subspecies. The absence of csrB in subspecies enterica positively correlated with weaker environmental biofilm formation. This may contribute to subspecies arizonae and diarizonae being better biofilm formers. Full article

Eighteen short- to medium-chain monounsaturated fatty acids were screened for hydroxylation and epoxidation using eleven different peroxygenase preparations. Most of these unspecific peroxygenases (UPOs) are secreted by fungal species of the dark-spored basidiomycetous families Psathyrellaceae and Strophariaceae, two belonged to the white-spored genus Marasmius (Marasmiaceae), and one belonged to the ascomycetous family Chaetomiaceae. The fatty acids (FAs) studied were categorized into three groups based on the position of the double bond: (i) terminal unsaturated FAs (between ω and ω-1), (ii) α-β-unsaturated FAs (between C2 and C3), and (iii) β-γ-unsaturated FAs (between C3 and C4). Their chain lengths ranged from three to nine carbon atoms. FAs with a terminal double bond were significantly oxidized by only two UPOs, namely CglUPO and CraUPO (peroxygenases from Chaetomium globosum and Coprinellus radians, respectively), producing different products. FAs with internal double bonds were converted by all tested UPOs. While epoxides were observed as products in the case of α-β-unsaturated fatty acids, only CglUPO formed β-γ-epoxides from the corresponding FAs. The product pattern of the other UPOs for β-γ-unsaturated FAs was quite similar. On the other hand, the product pattern for oxidized α-β-unsaturated FAs was more variable and, in some cases, specific to a particular UPO. For example, in the reaction with trans-2-nonenoic acid, the enzymes clustered into six groups based on the formed products. Full article

Virus-like particles (VLPs) comprise viral structural proteins that self-assemble to form a particle similar to the native virus capsid. Since their discovery, they have been employed mainly as vaccines to prevent viral infection because they can elicit an immune response. Besides their use as vaccines, their application in cancer prevention and drug delivery is under intensive investigation. They can be produced in different systems such as bacteria, mammalian, plant, insect, and yeast cells. The main hurdle for their use is establishing a platform for production because many variables need to be considered. First, VLPs must be effective in the action for which they are constructed, depending on the nature of the VLPs. Second, the production platform must be suitable for safe and high-scale production. Yeast has been shown to be a valuable tool in VLP production, as it is able to express heterologous proteins efficiently and its manipulation is cheap and easy. Several species have been employed for this purpose. In the present review, we analyze the features of different yeast species and how they have been used to produce VLPs. Full article

Biological soil amendments of animal origin (BSAAO), such as animal waste or animal-waste-based composts, may contain foodborne pathogens such as Listeria monocytogenes. Due to the ubiquitous nature of Listeria, it is essential to understand the behavior of L. monocytogenes in BSAAO in order to develop preharvest prevention strategies to reduce pathogen contamination. As biological control agents, competitive exclusion (CE) microorganisms have been widely utilized in agriculture to control plant- or foodborne pathogens. Due to the diverse microbial community, animal wastes and composts are the potential sources for isolating CE strains for pathogen control. To explore the potential of using CE to control L. monocytogenes in BSAAO, we thoroughly reviewed the studies on the fate of L. monocytogenes in the agriculture field, and in the isolation and identification of CE from different matrices, and the applications of CE as a biological control method. Future studies using a next-generation sequencing approach to identify and characterize CE strains in complex microbial communities can provide a comprehensive picture of the microbial interactions between invading pathogens and the indigenous microbiota in BSAAO. This comprehensive review will provide insight into the development of effective biological control measures for preventing L. monocytogenes contamination in the agricultural field and enhancing food safety. Full article

Some species of oral bacteria can reduce dietary nitrate to nitrite, which can later be converted to nitric oxide in the nitrate—nitrite—nitic oxide pathway. Increasing nitric oxide availability can reduce blood pressure (BP) and improve exercise performance. Streptococcus salivarius M18 (Streptococcus salivarius M18) is a bacteriocin-producing probiotic that is known to improve oral health by inhibiting pathogenic oral bacteria. However, it is presently unclear whether probiotic-induced alterations to the oral microbiome will influence circulating levels of nitric oxide metabolites and BP. Purpose: To determine the effects of Streptococcus salivarius M18 supplementation on plasma and salivary nitrate and nitrite levels and BP. Methods: Ten healthy males (age 32 ± 8 y, body mass 88.2 ± 15.1 kg) completed 2 × 14-day supplementation phases in a randomized order at least 14 days apart. In one phase, participants consumed Streptococcus salivarius M18 probiotic lozenges (2.5 billion colony-forming units/dose) once per day, and in the other, they ingested water (placebo). The abundance of bacteria on the tongue was assessed via Illumina 16S rRNA gene sequencing, unstimulated saliva, and venous blood samples were collected, and BP was measured pre and post each phase. Saliva and plasma were analysed for nitrate and nitrite using chemiluminescence, and pH was measured in saliva. The change in each outcome from pre- to post-supplementation was compared between phases using repeated measures ANOVA. Results: Plasma nitrite increased from baseline following probiotic supplementation (from 173 ± 39 to 223 ± 63 nM, p = 0.003, 95% CI 192–250 nM). In comparison, there was no change in the placebo phase or between baselines (all p > 0.05). The abundance of nitrite-producing bacteria was not altered, salivary nitric oxide metabolites and pH did not change, and the increase in plasma nitrite did not result in reductions in BP (all p > 0.05). Conclusions: Supplementation with Streptococcus salivarius M18 increased plasma nitrite, a key marker of NO availability. Despite this, Streptococcus salivarius M18 did not lower BP in these healthy normotensive participants. Additionally, the increase in plasma nitrite was not associated with abundance changes in bacteria thought important to NO generation. Further research is required to determine the mechanism behind the increase in plasma nitrite and the potential therapeutic and ergogenic benefits of Streptococcus salivarius M18 supplementation. Full article

Wastewater treatment plants receive influent wastewater that is contaminated with bacterial pathogens which may be released into the environment if the plant effluent is inadequately treated. In this study, next-generation sequencing was used to perform a 16S rDNA-based survey of bacterial populations in the influent and effluent from a treatment facility in the North-West Province (SA). In total, 3638 and 3872 effective DNA reads were obtained for the influent and effluent, respectively. Sequence analysis revealed the detection of a diverse bacterial constituency in both the influent and effluent samples. The phyla: Proteobacteria (49.82% and 52.04%), Firmicutes (14.06% and 13.14%) and Actinobacteria (5.00% and 9.99%) were found to be taxonomically abundant in the influent and effluent, respectively. This translated to the detection of biological treatment-, fecal coliform-, and disease-associated bacterial groups that are classified under the following genera: Escherichia spp., Serratia spp., Aeromonas spp., Legionella spp., Pseudomonas spp., Mycobacterium spp., Clostridium spp., Staphylococcus spp. and Streptococcus spp., Comamonas spp., Nitrosomonas spp., Acinetobacter spp., Rhodobacter spp., Paracoccus spp., Hyphomicrobium spp., and Desulfovibrio spp. Full article

(1) Background: We aimed to explore the feasibility of collecting intrapartum maternal Group B Streptococcus (GBS) colonization and immediate post-birth neonatal GBS colonization cultures for use in a larger trial and to identify cases of residual GBS, which were hypothesized to be less common in the probiotics group. (2) Methods: This sub-study added additional outcome measures to the parent study to identify intrapartum and neonatal colonization and compare between probiotic and placebo groups and to identify cases of residual GBS. Intrapartum maternal vaginal and rectal GBS cultures were collected at the time of admission to a hospital for labor and to give birth. Neonatal oral and nasopharynx GBS cultures were collected within 1–2 h of giving birth. (3) Results: Thirty intrapartum samples were collected; twenty-eight had complete data. The antepartum GBS results significantly predicted the intrapartum results (p = 0.005), with 86.7% of cultures remaining the same at both time points. There were four cases where the intrapartum GBS results were different to the 36-week antepartum cultures results. A case of residual GBS was identified in one probiotic group participant. None of the neonatal swabs were positive for GBS. No cases of EOGBSD occurred in infants born to the study participants. (4) Conclusions: Although the 36–37 week GBS results significantly predicted the intrapartum results, the utility for a larger research trial on probiotics to reduce antenatal GBS is unclear. Intrapartum GBS swab collection was feasible in a busy nurse, midwife, and physician practice. GBS was not recovered from neonatal oral and nasopharyngeal swabs. The pathways of neonatal GBS colonization require further study. Full article

Colorants have many applications in food, cosmetics, pharmaceutics, textile, paints, plastics, paper, ink and photographic industries. Colorants are classified according to their solubility into dyes and pigments. Those of natural origin have many advantages over synthetic ones, as natural colorants usually do not induce allergies or other health problems. In addition, their consumption in the food and drug industries is fortified with nutritional and health benefits as the majority of them possess antioxidant activity or can be used to produce some vitamins. Plants, animals, insects and microorganisms are rich sources of colorants. However, microbial pigments are favored over other natural pigments due to their higher yield, stability, economical production. Therefore, we focus in this review on fungal pigments, the history of their use, their chemistry and their applications in food and non-food fields. Additionally, the ability of the fungal genus, Epicoccum, to produce pigments is discussed. Moreover, the challenges and future prospects concerning fungal pigment production are highlighted in detail. Full article

Incubation of the yeast S. cerevisiae with glucose, in the absence of other nutrients, leads to Sugar-Induced Cell Death (SICD), accompanied by the accumulation of Reactive Oxygen Species (ROS). Yeast acidifies the environment during glucose metabolism not only as a result of the activity of the H⁺-ATPase of the plasma membrane but also due to the release of carboxylic acids. Acetic acid is known to induce apoptosis in growing yeast. We analyzed the composition of the incubation medium and found octanoic acid (OA) but no other carboxylic acids. Its concentration (0.675 µM) was significantly lower than the one at which OA had a toxic effect on the cell. However, the theoretically calculated concentration of OA inside the cell (about 200 μM) was found to be high enough to lead to cell necrosis. To test the hypothesis that OA might cause SICD, we used a ΔACP1 strain incapable of synthesizing OA in the yeast mitochondrial Fatty Acid Synthesis type II system (FAS-II). The deletion of the ACP1 gene did not affect the OA content in the medium. But, on the other hand, OA is a precursor of lipoic acid, which has antioxidant properties. However, strains with deleted genes for lipoic acid biosynthesis from OA (ΔPPT2, ΔLIP2, ΔLIP5, and ΔSGV3) showed no change in ROS and SICD levels. Thus, lipoic acid synthesized in FAS-II does not protect cells from ROS accumulated during SICD. We conclude that OA synthesized in the mitochondrial FAS-II system and its derivative lipoic acid are not involved in SICD in yeast S. cerevisiae. Full article

Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium, holds a prominent position as an antibiotic-resistant priority pathogen, according to the World Health Organization. Particularly prevalent in healthcare settings, this bacterium acts as an opportunistic pathogen, causing nosocomial infections. The significant antibiotic resistance observed in P. aeruginosa is multifactorial, encompassing intrinsic, acquired, and adaptive resistance mechanisms. The present study aims to explore specific RND-type efflux pump genes implicated in the acquisition of antibiotic resistances during the transition of P. aeruginosa PAO1 from its planktonic state to the more formidable and resistant biofilm form. This investigation is centered on MexB, a prominent RND-type efflux pump in P. aeruginosa. Our research is focused on MexB, a highly significant component characterized by its broad substrate specificity, primary function as the primary efflux pump, substantial expression levels, and notable clinical implications. Considering MexB’s critical role in expelling various clinically relevant antimicrobial agents and its significant contribution to multidrug resistance, our study aims to evaluate the comparative efficacy of three distinct antibiotic categories, namely, Ofloxacin (OFX), Tobramycin (TOB), and Ceftazidime (CAZ), in regulating the expression levels of identified multidrug efflux pump genes associated with the biofilm’s ability to remove antibiotics from bacterial cells. Expression analysis of efflux transporter genes in P. aeruginosa was performed by isolating total RNA from both planktonic and biofilm samples, both untreated and treated with Tobramycin (TOB), Ofloxacin (OFX), and Ceftazidime (CAZ). Real-time quantitative reverse transcriptase PCR was employed to investigate changes in the expression levels of MexA, MexB, MexX, MexY, OprM, and RPSL genes in the collected samples. In the absence of antibiotic treatment, the MexB efflux pump gene exhibited higher expression compared to other efflux pump genes in the biofilm’s state, supporting its involvement in multidrug resistance when active. To further explore the role of the MexB gene in antibiotic resistance, P. aeruginosa was cultured in both planktonic and biofilm forms while simultaneously treating them with TOB, OFX, and CAZ. Among the three antibiotics employed, OFX demonstrated superior efficacy in inhibiting the growth of biofilms by downregulating the expression of the Mex B efflux pump gene in P. aeruginosa, thereby enhancing its susceptibility to OFX. TOB yielded comparable outcomes to OFX, albeit with a slightly lesser extent of Mex B expression reduction. Conversely, CAZ exhibited ineffectiveness in reducing MexB gene expression in both biofilm and planktonic forms of the organism, rendering it incapable of eradicating the pathogen. Full article

Background: Abortion is a spontaneous loss of pregnancy before 20 weeks. Approximately 42 million pregnancies end in abortion. The maternal infections that are transmissible from mother to fetus are caused by many pathogens, of which the TORCH complex contributes majorly to neonatal and infant deaths globally. The aim of this study is to detect the prevalence and types of infectious causes of abortion. One hundred aborted women admitted to King Faisal Medical Complex Maternity Hospital in Taif City between the period of 2018 and 2020 were enrolled in this study. The serological test reports (TORCH panel), as well as reports of hematological (CBC) and chemical parameters, were obtained from laboratory management system databases, reviewed, and then analyzed. The H&E-stained microscopic slides of their product of conception (POC) were examined under a microscope and compared with histopathological reports. The prevalence of TORCH infections was 8% in aborted women. Hepatitis B virus (HBV) and mixed TORCH infections constituted the highest percentage of TORCH pathogens in aborted women, constituting 6%. The most detected histopathological finding in seropositive cases (50%) was POC, with mixed inflammatory infiltrates and chronic endometritis, while in seronegative aborted women, POC was normal (64.1%). There is a statistically significant increase in the mean count of white blood cells in seropositive women. Therefore, it is important to provide health campaigns to bring awareness to the population about the risk factors of infectious agents to be avoided, especially during pregnancy. Full article

We previously showed that insertion of Dictyostelium gene sequences, such as mlcR, upstream of the Shine–Dalgarno sequence, positively impacts downstream gene expression in Escherichia coli. However, the mechanism by which protein production is facilitated and its applicability to other bacteria remains unknown. In this study, a translation-enhancing effect, associated with this system, on the mRNA amount and property as well as the versatility of the method has been demonstrated. The insertion of mlcR-terminal 25 bp (mlcR25) stabilized the mRNAs and led to increased mRNA levels in E. coli. In the in vitro translation system, a four-fold enhancement was observed when DNA was used as the template, and a three-fold enhancement was observed when mRNA was used as the template. This suggests that mlcR25 has an effect on the facilitation of the interaction between mRNA and ribosome. Furthermore, when this enhancement system was adapted to the photosynthetic bacterium Rhodobacter capsulatus, a more than six-fold increase in translation was observed. Thus, we propose that enhanced translation by mlcR25 is mediated by mechanisms that help the translation machinery to work efficiently, and the system can be applied to bacteria other than E. coli. Full article

A combinatorial biofilm treatment involving a low dose of antibiotics along with a small amount of electricity is known as the bioelectric effect (BE). When an external electric field or current is applied, biofilms can be affected by the resulting electrostatic force. Our group is researching the maximization of electrostatic force through the integration of both alternating and direct currents, with a voltage below the electrolysis threshold (0.82 V). To validate the efficacy of this technology, in the present work we investigated two major biofilm applications: (1) dentistry for oral biofilm infection and (2) hygiene for aerobic biofilm contamination. For each application, testing devices were developed in the form of a toothbrush and an evaporator cleaner, respectively. The dental clinical results demonstrated a 75% reduction in gingivitis compared to the non-BE applied group (n = 40, ANOVA, paired t-test, p < 0.05). Meanwhile, the hygiene testing result demonstrated an 81.8% increase in biofilm removal compared to the initial untreated sample (n = 6, ANOVA, paired t-test, p < 0.05). In conclusion, this new BE technology showed efficacy in both dental- and hygiene-associated biofilms without causing electrolysis. Further investigation and development of the BE system should continue in both the medical and hygiene fields. Full article