جستجوی مقالات مرتبط با کلیدواژه "pathogenicity" در نشریات گروه "پزشکی"

Researchers have focused on Staphylococcus aureus because it is transmitted through food, such as milk and dairy products, and causes human diseases. Prevalence, antimicrobial resistance, presence, and distribution of methicillin-resistant S. aureus (MRSA) virulence genes isolated from raw milk and dairy products were evaluated.

300 samples of dairy products were collected from Shahrekord, Iran. S. aureus was identified using biochemical tests and screened for sensitivity to 13 antibiotics to identify resistance genes. In addition, SCCmec typing was performed.

Out of 300, S. aureus was found in 82 samples. Raw milk had the highest contamination with S. aureus (60 of 82), followed by cheese (15 of 82), and butter (7 of 82). At least one resistance gene was present in every isolate of S. aureus. Virulence factors and enterotoxin-coding genes, such as sea, seb, sec, and sed were highly distributed.

The results of this study revealed the presence of toxin-producing MRSA strains in raw milk and dairy products. MRSA in dairy farms is an important risk factor for the spread of staphylococcal infections; therefore, further studies are needed to find strategies for controlling the presence of S. aureus, especially MRSA, in dairy products.

Many domestic and wild avian species are afflicted with Newcastle disease virus (NDV), an infectious bird illness. It is a zoonotic illness with a broad geographic prevalence. The avian paramyxovirus serotype 1 virus, together with viruses of the other eight serotypes (avian paramyxovirus 1–9), has been classified as belonging to the genus Avulavirus, subfamily paramyxovirinae, and family paramyxoviridae. Most of Asia, Africa, and certain North and South American nations have endemic outbreaks of the dangerous NDV virus in chickens. The clinical symptoms of Paramyxovirus, a virus with a global distribution that affects chickens of all ages, vary greatly depending on the viral strain, species and age of the bird, treatment, concomitant diseases, and pre-existing immunity. Respiratory aerosols, exposure to faeces and other excretions fromdiseased birds, recently introduced birds, selling and giving away ill birds, and contact with contaminated feed, water, equipment, cannibalism,and clothes are all ways that NDV is spread. The clinical manifestations of the illness include rales, tremors, paralyzed wings and legs, twistednecks, circling, colonic spasms, and total paralysis. When a human is exposed to high levels of the virus, Newcastle disease virus may result inconjunctivitis. Since the dawn of civilization, natural remedies derived from plants, animals, microorganisms, and marine sources have beenused to cure a variety of illnesses. The basis for contemporary drug research is information from our predecessors. This review aims to provide asuccinct overview of the effects of herbal medicines in treating the Newcastle disease virus.

 Candida albicans (C. albicans) is notably pathogenic due to its ability to form biofilms that are resistant to conventional antifungal treatments.

 This study aims to explore the effectiveness of Streptomyces cellulosae (S. cellulosae) extract in disrupting biofilm formation by targeting specific genes within C. albicans.

 The study began by isolating S. cellulosae from soil and C. albicans from clinical specimens. S. cellulosae was then cultured and fermented to produce bioactive compounds. The ability of these extracts to inhibit C. albicans biofilm formation was tested using a crystal violet assay. Additionally, the effects of the S. cellulosae extracts on the expression of biofilm-related genes in C. albicans were evaluated using quantitative real-time PCR (qRT-PCR). The growth rates of C. albicans were also measured to determine the impact of the extracts.

 The crude extract of S. cellulosae significantly (P < 0.05) inhibited the formation of C. albicans biofilms at concentrations exceeding 0.5 µg/mL, with the inhibition becoming more pronounced at concentrations above 2.0 µg/mL. The qRT-PCR results showed significant changes in the expression of biofilm-related genes ALS1, ALS3, and EFG1 at different extract concentrations (P < 0.05). The extract also significantly affected the expression of the HWPa and BRG1 genes.

 The crude extract of Streptomyces cellulosae shows potential as a novel antibiofilm agent against C. albicans. This finding opens new avenues for research and potential therapeutic applications in combating biofilm-associated infections.

 In hospitals and communities, Methicillin-resistant Staphylococcus aureus (MRSA) plays a critical role due to its ability to acquire resistance against several antibiotics and play a role in the spread of diseases.

 This research aimed to investigate the pattern of antibiotic resistance in MRSA isolates and perform molecular typing of MRSA isolates using various elements, including SCCmec type, ccr type, prophage type, and gene toxin profiles.

 The research spanned 20 months at Al-Zahra Hospital in Isfahan and involved 148 isolates from various anatomical sites. The isolates were evaluated for their antibiotic susceptibility patterns. They were characterized by screening for SCCmec typing, ccr typing, phage typing, and PCR profiling of pvl, hlb, sak, eta, and tst toxin genes.

 From 148 total S. aureus isolates, 42% (n = 62) were methicillin-resistant. The MRSA isolates demonstrated substantial resistance to penicillin and ciprofloxacin, and 90.3% of MRSA isolates were multiple-drug resistant. Also, SCCmec types III, I, and IV were identified in 45.16%, 35.48%, and 19.35% of MRSA isolates, respectively. Also, seven prophage patterns and 15 toxin patterns were detected among MRSA isolates.

 Multi-drug resistance is common among MRSA isolates. The only effective drug among the investigated antibiotics was chloramphenicol. The MRSA isolates can be controlled by changing the prescribing procedure of antibiotics and applying infection control strategies. The studied MRSA isolates can cause a wide range of diseases due to having several bacteriophages that encode virulence factors. Identification of different types of prophages may be useful in predicting such pathogenic agents.

Listeria monocytogenes (LM) is a facultative intracellular pathogen that causes food-borne infections in humans and animals. To invade and multiply within host cells, LM utilizes various strategies to precisely modulate its gene expression and to adapt to the in vivo environment.

To investigate the regulatory roles of Rli82 sRNA in the motility and pathogenicity of LM EGD-e.

The Rli82 gene knock-out mutant strain, LM-
Rli82, and the complementation strain, LM-
Rli82/Rli82, were constructed using homologous recombination technology, and their motility and virulence, respectively, were determined. Moreover, the potential target mRNA regulated by Rli82 was predicted using TargetRNA2 software, and then the interaction between the target mRNA and Rli82 was verified by the two-plasmid reporter system.

The results showed that the motility of LM-
Rli82 was significantly increased at 25°C, facilitated by the production of more flagella than LM EGD-e and LM-
Rli82/Rli82. Furthermore, LD50 in LM-
Rli82-infected mice was significantly increased as compared to LM EGD-e and LM-
Rli82/Rli82, suggesting that the virulence of LM was weakened when the Rli82 gene was deleted. In addition, the mRNA level of flaA was not significantly elevated, but flaA protein was significantly higher in LM-
Rli82 than in LM EGD-e and LM-
Rli82/Rli82, suggesting that Rli82 might modulate the translation of flaA mRNA at the post-transcriptional level.

Taken together, our findings for the first time revealed that Rli82 sRNA might be involved in the modulation of the expression of flaA protein, thereby influencing the mobility and pathogenicity of LM.

Pseudomonas aeruginosa (P. aeruginosa) has a wide range of virulence factors. These factors have the potential to increase bacterial pathogenicity and serious infection. The purpose of this study was to evaluate the virulence profiles and antibiotic susceptibility of isolates of P. aeruginosa originated from animal and human samples. The samples were cultured on selective media before being extracted for DNA and subjected to a PCR technique to detect virulence genes. There was a significant difference in the isolation of P. areuginosa isolated from human and animal sources. Where, in humans, the percentage of P. areuginosa was 52 (68.42%) while in animals the percentage of P.aeruginosa was 24 (31.57%). In humans, the percentage of P. aeruginosa in blood was 26.92% (14 isolates), in urine it was 25% (13 isolates), in wound it was 40.38%21 isolates), and in sputum it was 7.69% (4 isolates). We used a PCR technique that produced highly specific and accurate results for detecting virulence factor genes in P. aeruginosa isolates that cause disease in humans and animals. The percentage of exoA genes was (83.33%) and (81.66%) in the animal and human, and that of lasB was (58.33%) and (92.30%) in animal and human samples respectively. Furthermore, both the exoA and lasB genes are found in 26.31% of animal strains and 17.10% of human strains. The disc diffusion method was used to determine antimicrobial susceptibility. In both animal and human isolates, P. aeruginosa showed the highest resistance to amikacin and the lowest resistance to ciprofloxacin. These findings could aid in the understanding of pathogenicity processes, treatment direction, and the development of strategies to control the spread of epidemic P. aeruginosa strains.

Probiotics are commonly defined as live microorganisms (yeast or bacteria), when getting ingested in adequate amounts, they exhibit the beneficial effects on the host. During the past two decades, probiotic microorganisms as health-promoting agents have been increasingly added to various types of food products, especially in fermented food and also drugs. Due to the importance of food safety aspects of the human diet and with regards to some adverse effects of probiotics for human, we decided to carry out a review on probiotics and their adverse effects byresearch in literature. Previous studies indicated that several aspects, including safety, functional and technological characteristics, have to be considered in the selection of probiotic microorganisms. Safety aspects include origin (gastrointestinal tract of healthy human), non-pathogenicity and antibiotic resistance. Some probiotic microorganisms such as enterococci have been considered as an opportunistic pathogen for humans and cause disease, possess agents for antibiotic resistance and potential virulence factors. The bacteria used as a probiotic in food should be completely safe. Probiotic bacteria should be chosen from the healthy human micro-flora and should not have any antibiotic resistance that would prevent treatment of a rare probiotic infection. This review focused on key issues concerning the safety aspects of probiotics added to particular food products for improvement of general health and also discussed the criteria for probiotic selection in details.