Pathogenic Bacteria
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2024 ◽  
Vol 84 ◽  
Author(s):  
R. Ullah ◽  
A. W. Qureshi ◽  
A. Sajid ◽  
I. Khan ◽  
A. Ullah ◽  
...  

Abstract Fish is the main source of animal protein for human diet. The aim of this study was to find out prevalence of pathogenic bacteria of two selected economically important fish of Pakistan namely Mahseer (Tor putitora) and Silver carp (Hypophthalmichthys molitrix). Live fish samples from hatcheries and dead fish samples from different markets of study area were randomly collected. The fish samples were analyzed for isolation, identification and prevalence of bacteria. The isolated bacteria from study fish were identified through biochemical test and about 10 species of pathogenic bacteria were identified including the pathogenic bacteria to human and fish namely, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus iniae, Serratia spp. Citrobacter spp. Stenotrophomonas spp. Bacillus spp. and Salmonella spp. The bacterial percentage frequency of occurrence in Silver carp and Mahseer fish showed Pseudomonas aeruginosa 21.42%, Staphylococcus epidermidis 17.85%, Escherichia coli 11.90%, Staphylococcus aureus 9.52%, Citrobacter spp. 9.52%, Serratia spp. 8.33%, Streptococcus iniae 7.14%, Stenotrophomonas spp. 5.95%, Bacillus spp. 4.76% and Salmonella spp. 3.57%. The study revealed that Fish samples of Mahseer and Silver carp that were collected from markets have found more isolates (10 bacterial species) than did the fresh fish pond samples (03 bacterial species) of hatcheries. The occurrence of pathogenic bacteria in study fish showed risk factor for public health consumers.


Author(s):  
Janette Chammas ◽  
Mallika Iyer ◽  
George Minasov ◽  
Ludmilla Shuvalova ◽  
Wayne Anderson ◽  
...  

Pathogenic bacteria attack their host by secreting virulence factors that in various ways interrupt host defenses and damage their cells. Functions of many virulence factors, even from well-studied pathogens, are still unknown. Francisella tularensis is a class A pathogen and a causative agent of tularemia, a disease that is lethal without proper treatment. Here we report the three-dimensional structure and preliminary analysis of the potential virulence factor identified by the transcriptomic analysis of the F. tularensis disease models that is encoded by the FTT_1539 gene. The structure of the FTT_1539 protein contains two sets of three stranded antiparallel beta sheets, with a helix placed between the first and the second beta strand in each sheet. This structural motif, previously seen in virulence factors from other pathogens, was named the SHS2 motif and identified to play a role in protein-protein interactions and small molecule recognition. Sequence and structure analysis identified FTT_1539 as a member of a large family of secreted proteins from a broad range of pathogenic bacteria, such as Helicobacter pylori and Mycobacterium tuberculosis. While the specific function of the proteins from this class is still unknown, their similarity to the H. pylori Tip-α protein that induces TNF-a and other chemokines through NF-kB activation suggests the existence of a common pathogen-host interference mechanism shared by multiple human pathogens.


Biocelebes ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 113-124
Author(s):  
Musjaya, M Guli

The immune sistem is a way of the body’s defense sistem to save the host from the invasion of outside pathogen. Based on how respon to disease, that differentiated into two immune system are innate and adaptive system. Because it an cant throgh the stomach, these pathogenic bacteria go to the small intestin as a site infection. In the intestine, V. cholerae bactesia adhere and colonize and invasion to intestinal epihelial cells. Protection mechanism  to V. cholerae are the natural defense presence of tick mucosa on the surface of epithelial cells can  inhibit pathogene to adhere tointestinal epithelial cells. One anothet defense namely innate immune system did by phagocytic cells to attac pathogen agent and adaptive immune system involves IgA to opsonization so that can increase intestinal mucosal immune system


2022 ◽  
Vol 9 ◽  
Author(s):  
Santiago M. C. Lopez ◽  
Nader Shaikh ◽  
Monika Johnson ◽  
Hui Liu ◽  
Judith M. Martin ◽  
...  

Objective: Children with no pathogenic bacteria in the nasopharynx are unlikely to have acute bacterial sinusitis. We evaluated whether information on clinical presentation, viral co-detection, and mucosal cytokine levels could be used to predict presence of bacteria in the nasopharynx.Method: We obtained nasopharyngeal (NP) swabs from children diagnosed with acute sinusitis. NP swabs were processed for bacterial culture, viral PCR testing, and cytokine expression. We examined whether results of the bacterial culture could be predicted based on the presence of clinical information, presence of viruses or mucosal cytokine levels.Results: We enrolled 174 children; 123 (71%) had a positive culture for potentially pathogenic bacteria and 51 (29%) had normal flora. 122/174 (70%) tested positive for one or more viruses. Compared to children with normal flora, children with pathogenic bacteria were more likely to have viruses (p < 0.01), but this relationship disappeared when we adjusted for age. Children with pathogenic bacteria in their nasopharynx and children with normal flora had similar levels of nasal cytokines.Conclusion: In children with clinically diagnosed acute sinusitis, clinical presentation, levels of nasal cytokines, and presence of viruses do not differentiate children with and without pathogenic bacteria in their nasopharynx.


Author(s):  
Christin Bartlitz ◽  
Rafał Kolenda ◽  
Jarosław Chilimoniuk ◽  
Krzysztof Grzymajło ◽  
Stefan Rödiger ◽  
...  

Pathogenic bacteria, such as enteropathogenic (EPEC) and enterotoxigenic Escherichia coli (ETEC), cause diarrhea in mammals. In particular, E. coli colonize and infect the gastrointestinal tract via type 1 fimbriae (T1F). Here the major zymogen granule membrane glycoprotein 2 (GP2) acts as host cell receptor. GP2 is also secreted by the pancreas and various mucous glands, interacting with luminal type 1 fimbriae-positive E. coli . It is unknown whether GP2 isoforms demonstrate specific E. coli pathotype binding. In this study, we investigated interactions of human, porcine and bovine EPEC, ETEC as well as commensal E. coli isolates with human, porcine and bovine GP2. We first defined pathotype- and host-associated FimH variants. Secondly, we could prove that GP2 isoforms bound to FimH variants to varying degrees. However, the GP2-FimH interactions did not seem to be influenced by the host specificity of E. coli . In contrast, soluble GP2 affected ETEC infection and phagocytosis rates of macrophages. Pre-incubation of ETEC pathotype with GP2 reduced infection of cell lines. Furthermore, pre-incubation of E. coli with GP2 improved the phagocytosis rate of macrophages. Our findings suggest that GP2 plays a role in the defense against E. coli infection and in the corresponding host immune response. IMPORTANCE Infection by pathogenic bacteria such as certain Escherichia coli pathotypes results in diarrhea in mammals. Pathogens, including zoonotic agents, can infect different hosts or show host-specificity. There are Escherichia coli strains which are frequently transmitted between humans and animals, whereas other Escherichia coli strains tend to colonize only one host. This host-specificity is still not fully understood. We show that glycoprotein 2 is a selective receptor for particular Escherichia coli strains or variants of the adhesin FimH but not a selector for a species-specific Escherichia coli group. We demonstrate that GP2 is involved in the regulation of colonization and infection and thus represents a molecule of interest for the prevention or treatment of disease.


2022 ◽  
Author(s):  
Vivekananda Mandal ◽  
Narendra Nath Ghosh ◽  
Prashanta Kumar Mitra ◽  
Sukhendu Mandal ◽  
Vivekananda Mandal

Abstract Objectives: The present study aims to report on the production optimization, purification, and characterization of structural and functional attributes of a novel broad-spectrum antibacterial compound produced by Aspergillus fumigatus nHF-01 (GenBank Ac. No. MN190286).Materials and Methods: The culture conditions were optimized by using rigorous culture-set preparation considering various abiotic and biotic factors for a higher amount of antimicrobial production. The produced antimicrobial was solvent extracted and purified by preparative TLC and HPLC methods followed by characterization using UV-Vis, FT-IR, ESI-MS, and 1H-NMR spectroscopy. The MIC and MBC of the antimicrobials were determined against a set of Gram-positive and Gram-negative human pathogenic bacteria. The mode of action on cellular morphology and integrity were determined by LDH and SEM studies. Its biofilm-inhibition properties and synergistic activity with antibiotics were studied. The possible cytotoxic effect on human cell lines was also tested by MTT assay. The putative target site of action was evaluated through in silico molecular docking study. Results: The micro-fungus A. fumigatus nHF-01 produced the maximum antibacterial compound while grown in a combination of 2% MEB (w/v) and 4% YE (w/v) at pH 6.0 and 20 °C temperature with 100 rpm agitation for ten days. The DCM extractable crude compound has a potent growth inhibition against the target human food and topical pathogenic bacteria at a 15 mg/ml concentration and is stable up to 100 °C. The spectroscopic studies confirmed the antimicrobial compound as 5-butyl-2-pyridine carboxylic acid with MIC values from 0.069±0.0034 to 1.12±0.052 mg/ml and from 8.925±0.39 to 17.85±0.78 mg/ml; and MBC values from 8.925±0.40 to 17.85±0.776 mg/ml and from 0.069±0.0034 to 0.139±0.0065 mg/ml against human pathogenic Gram-positive and Gram-negative bacteria, respectively. A concentration of 0.139 and 17.85 mg/ml decreased the viability sharply within 15 min of the incubation period with the gradual increase in LDH activity, indicating a robust bactericidal and lytic mode of action. The time-kill kinetics study shows that at a 17.85 mg/ml dose (i.e. MBC), the compound caused zero viability of E. coli and S. epidermidis cells from the initial log CFU/ml 5.78 after 15 h of treatment. It caused a remarkable change in morphology like the formation of blebbing, notch, rupture of the entire cell walls, and entire dissolution of cell integrity at a concentration of 4 µg/ml and 129 µg/ml. It had cytotoxicity against the tested human lung carcinoma A549 cell line. It showed a notable antibiofilm activity at 20 µg/ml and 4 µg/ml comparable to the standard antibiofilm drug usnic acid 10 µg/ml and 64 µg/ml against E. coli and B. cereus. It had a synergistic activity with streptomycin, whereas ciprofloxacin and vancomycin showed additive effects. It showed the highest binding affinities with Quinol-Fumarate Reductase (1l0v), a respiratory enzyme. Conclusion: Thus, the above findings can be concluded that the strain A. fumigatus nHF-01 produces a novel broad-spectrum antimicrobial compound 5-butyl-2-pyridine carboxylic acid with potent bactericidal activity against human food and topical pathogenic bacteria. This is the first report of such a compound from the A. fumigatus.


Author(s):  
Nicole Hugouvieux‐Cotte‐Pattat ◽  
Monique Royer ◽  
Erwan Gueguen ◽  
Paul Le Guen ◽  
Roderich D. Süssmuth ◽  
...  

Author(s):  
Lijiao Liang ◽  
Ping Wang ◽  
Tianming Qu ◽  
Xiaomei Zhao ◽  
Yiqiang Ge ◽  
...  

Abstract Introduction The raw milk is the basic raw material of dairy products, Bacillus cereus is a typical conditional pathogenic bacteria and cold-phagocytic spoilage bacteria in raw milk. This study established a qPCR method for detecting B. cereus in raw milk Materials and Methods In this study, a qPCR method for detecting B. cereus in raw milk was established. The specificity of the method was verified by using other Bacillus bacteria and pathogenic bacteria, the sensitivity of the method was evaluated by preparing recombinant plasmids and simulated contaminated samples, and the applicability of the method was verified by using pure spore DNA. The actual sample detection was completed by using the established qPCR method Results The qPCR established in this study can specifically detect B. cereus in raw milk. The LOD of the method was as low as 200 CFU/mL, and the LOQ ranged from 2 × 10 2 to 2 × 10 8 CFU/ml, the amplification efficiency of qPCR was 96.6% Conclusins The method established in this study can distinguish B. cereus from other Bacillus bacteria, and spore DNA can be used as the detection object. This method has the advantages of strong specificity, high sensitivity, wide application range and short detection time, which is expected to be applied in the dairy industry.


2022 ◽  
Author(s):  
Sahil Mahfooz ◽  
Jitendra Narayan ◽  
Ruba Mustafa Elsaid Ahmed ◽  
Amel Bakri Mohammed El Hag ◽  
Nuha Abdel Rahman Khalil Mohammed ◽  
...  

Abstract Pathogenic bacteria use phase variation of surface molecules and other characteristics as a significant adaptation mechanism. Repetitive sequences made up of numerous identical repeat units can be found in many phase variable genes. Here, we investigated the frequency and distribution of long-SSRs in 15 human pathogenic Staphylococcus, Streptococcus, and Enterococcus bacteria. Long-SSRs were found to be distributed differently in the genic and intergenic sequences. In the genic sequences, 61.3 SSRs were discovered on average, while 16.2 SSRs were found in the intergenic regions. Staphylococci exhibited the highest frequency of SSRs, followed by Enterococcus, and Streptococci had the lowest frequency of SSRs. Higher A+T content was found to be the best predictor of long-SSR in these human pathogens. Tetranucleotide repeats predominated in intergenic regions, while trinucleotide repeats predominated in genic regions. In human pathogenic Streptococcus and Staphylococcus bacteria, genus-specific encoding of amino acids by tri-nucleotide SSRs was observed. A genetic relationship between these human pathogenic bacteria was derived based on the presence of SSRs in the housekeeping genes and compared to the phylogeny generated based on the 16S ribosomal RNA gene.


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