Potential Probiotics Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Co-Aggregate with Clinical Isolates of Proteus mirabilis and Prevent Biofilm Formation

2020 ◽  
Vol 12 (4) ◽  
pp. 1471-1483 ◽  
Author(s):  
Ammar Algburi ◽  
Sarah A. Alazzawi ◽  
Ali Ibrahim Ali Al-Ezzy ◽  
Richard Weeks ◽  
Vladimir Chistyakov ◽  
...  
Author(s):  
Nguyễn Thị Bích Đào ◽  
Trần Quang Khánh Vân ◽  
Nguyễn Văn Khanh ◽  
Nguyễn Quang Linh

Khi tình hình bệnh hội chứng tôm chết sớm (EMS) đã gây thiệt hại vô cùng to lớn đối với Nuôi trồng thủy sản thì các giải pháp được đề nghị và áp dụng nhằm hạn chế dịch bệnh. Trong đó, việc tìm hiểu và đưa vi khuẩn có lợi để cạnh tranh và ức chế loài vi khuẩn gây bệnh rất được quan tâm, được cho là giải pháp có nhiều triển vọng phù hợp với điều kiện môi trường, đảm bảo sức khỏe cho con người, cũng như hạn chế được dịch bệnh. Đặc biệt, đưa vi khuẩn Bacillus spp. qua đường tiêu hóa của tôm ngay từ khi mới thả đã hạn chế được mật độ vi khuẩn Vibrio. Nghiên cứu này đã phân lập được các chủng Bacillus subtilis B1, Bacillus subtilis B2, Bacillus amyloliquefaciens B4và thử khả năng đối kháng với vi khuẩn Vibrio parahaemolyticus V1 ở các nồng độ 103, 104, 105, 106 CFU theo dõi ở các thời điểm 6h, 12h, 24h, 48h và 72h. Kết quả cho thấy cả ba chủng vi khuẩn Bacillus trên phân lập được đều có khả năng ức chế tốt vi khuẩn Vibrio parahaemolyticus V1, trong đó vi khuẩn Bacillus amyloliquefaciens B4 làtốt nhất với đường kính vòng kháng khuẩn 52,67 ± 4,31mm ở thời điểm 48h; hai chủng Bacillus subtilis B1, Bacillus subtilis B2 lầnlượt là  49,67 ± 3,15 mm, 44,07 ± 5,19 mm, với mức sai số có ý nghĩa thống kê p < 0,05.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdelazeem M. Algammal ◽  
Hany R. Hashem ◽  
Khyreyah J. Alfifi ◽  
Helal F. Hetta ◽  
Norhan S. Sheraba ◽  
...  

AbstractProteus mirabilis is a common opportunistic pathogen causing severe illness in humans and animals. To determine the prevalence, antibiogram, biofilm-formation, screening of virulence, and antimicrobial resistance genes in P. mirabilis isolates from ducks; 240 samples were obtained from apparently healthy and diseased ducks from private farms in Port-Said Province, Egypt. The collected samples were examined bacteriologically, and then the recovered isolates were tested for atpD gene sequencing, antimicrobial susceptibility, biofilm-formation, PCR detection of virulence, and antimicrobial resistance genes. The prevalence of P. mirabilis in the examined samples was 14.6% (35/240). The identification of the recovered isolates was confirmed by the atpD gene sequencing, where the tested isolates shared a common ancestor. Besides, 94.3% of P. mirabilis isolates were biofilm producers. The recovered isolates were resistant to penicillins, sulfonamides, β-Lactam-β-lactamase-inhibitor-combinations, tetracyclines, cephalosporins, macrolides, and quinolones. Using PCR, the retrieved strains harbored atpD, ureC, rsbA, and zapA virulence genes with a prevalence of 100%, 100%, 94.3%, and 91.4%, respectively. Moreover, 31.4% (11/35) of the recovered strains were XDR to 8 antimicrobial classes that harbored blaTEM, blaOXA-1, blaCTX-M, tetA, and sul1 genes. Besides, 22.8% (8/35) of the tested strains were MDR to 3 antimicrobial classes and possessed blaTEM, tetA, and sul1genes. Furthermore, 17.1% (6/35) of the tested strains were MDR to 7 antimicrobial classes and harbored blaTEM, blaOXA-1, blaCTX-M, tetA, and sul1 genes. Alarmingly, three strains were carbapenem-resistant that exhibited PDR to all the tested 10 antimicrobial classes and shared blaTEM, blaOXA-1, blaCTX-M, tetA, and sul1 genes. Of them, two strains harbored the blaNDM-1 gene, and one strain carried the blaKPC gene. In brief, to the best of our knowledge, this is the first study demonstrating the emergence of XDR and MDR-P.mirabilis in ducks. Norfloxacin exhibited promising antibacterial activity against the recovered XDR and MDR-P. mirabilis. The emergence of PDR, XDR, and MDR-strains constitutes a threat alarm that indicates the complicated treatment of the infections caused by these superbugs.


2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mathilde Nordgaard ◽  
Rasmus Møller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos‐Monterrosa ◽  
Ákos T. Kovács

2020 ◽  
Vol 401 (12) ◽  
pp. 1307-1322
Author(s):  
Gert Bange ◽  
Patricia Bedrunka

AbstractThe guanosine-based second messengers (p)ppGpp and c-di-GMP are key players of the physiological regulation of the Gram-positive model organism Bacillus subtilis. Their regulatory spectrum ranges from key metabolic processes over motility to biofilm formation. Here we review our mechanistic knowledge on their synthesis and degradation in response to environmental and stress signals as well as what is known on their cellular effectors and targets. Moreover, we discuss open questions and our gaps in knowledge on these two important second messengers.


2002 ◽  
Vol 46 (6) ◽  
pp. 2004-2006 ◽  
Author(s):  
R. Bonnet ◽  
H. Marchandin ◽  
C. Chanal ◽  
D. Sirot ◽  
R. Labia ◽  
...  

ABSTRACT Ten nonrepetitive Proteus mirabilis isolates, which were collected over 4 years (1996 to 1999) at the teaching hospital of Clermont-Ferrand, France, produced class D carbapenemase OXA-23. MICs of imipenem were 0.25 to 0.5 μg/ml for these clinical isolates. Molecular typing revealed that the 10 P. mirabilis isolates originated from the same clonal strain. Hybridization of I-CeuI-generated chromosome fragments with a bla OXA-23 probe showed that the gene was chromosome encoded in the P. mirabilis strain.


2021 ◽  
pp. 1-8
Author(s):  
Soheir A.A. Hagras ◽  
Alaa El-Dien M.S. Hosny ◽  
Omneya M. Helmy ◽  
Mounir M. Salem-Bekhit ◽  
Faiyaz Shakeel ◽  
...  

This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½–1/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymeric chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.


2015 ◽  
Vol 28 (10) ◽  
pp. 1102-1116 ◽  
Author(s):  
M. C. Magno-Pérez-Bryan ◽  
P. M. Martínez-García ◽  
J. Hierrezuelo ◽  
P. Rodríguez-Palenzuela ◽  
E. Arrebola ◽  
...  

Bacillus amyloliquefaciens CECT 8237 and CECT 8238, formerly known as Bacillus subtilis UMAF6639 and UMAF6614, respectively, contribute to plant health by facing microbial pathogens or inducing the plant’s defense mechanisms. We sequenced their genomes and developed a set of ad hoc scripts that allowed us to search for the features implicated in their beneficial interaction with plants. We define a core set of genes that should ideally be found in any beneficial Bacillus strain, including the production of secondary metabolites, volatile compounds, metabolic plasticity, cell-to-cell communication systems, and biofilm formation. We experimentally prove that some of these genetic elements are active, such as i) the production of known secondary metabolites or ii) acetoin and 2-3-butanediol, compounds that stimulate plant growth and host defense responses. A comparison with other Bacillus genomes permits us to find differences in the cell-to-cell communication system and biofilm formation and to hypothesize variations in their persistence and resistance ability in diverse environmental conditions. In addition, the major protection provided by CECT 8237 and CECT 8238, which is different from other Bacillus strains against bacterial and fungal melon diseases, permits us to propose a correlation with their singular genetic background and determine the need to search for additional blind biocontrol-related features.


2017 ◽  
Vol 63 (7) ◽  
pp. 608-620 ◽  
Author(s):  
Siyuan Chang ◽  
Xiaodong Chen ◽  
Shuo Jiang ◽  
Jinchun Chen ◽  
Lin Shi

Biofilm is a biological complex caused by bacteria attachment to the substrates and their subsequent reproduction and secretion. This phenomenon reduces heat transfer efficiency and causes significant losses in treated sewage heat-recovering systems. This paper describes a physical approach to inhibit bacteria settlement and biofilm formation by Bacillus subtilis, which is the dominant species in treated sewage. Here, micro-patterned surfaces with different characteristics (stripe and cube) and dimensions (1–100 μm) were fabricated as surfaces of interest. Model sewage was prepared and a rotating coupon device was used to form the biofilms. Precision balance, scanning electron microscopy, and confocal laser scanning microscopy (CLSM) were employed to investigate the inhibitory effects and the mechanisms of the biofilm–surface interactions. The results have shown that surfaces with small pattern sizes (1 and 2 μm) all reduced biofilm formation significantly. Interestingly, the CLSM images showed that the surfaces do not play a role in “killing” the bacteria. These findings are useful for future development of new process surfaces on which bacteria settlement and biofilm formation can be inhibited or minimized.


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