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virulence genes and biofilm formation

Cristian Alfredo Segura-Cerda, Michel de Jesús Aceves-Sánchez, Brenda Marquina-Castillo, Dulce Mata-Espinoza, Jorge Barrios-Payán, Perla Jazmín Vega-Domínguez, César Pedroza-Roldán, Jorge Bravo-Madrigal, Alba Adriana Vallejo-Cardona, Rogelio Hernández-Pando, Mario Alberto Flores-Valdez
Pellicles, a type of biofilm, have gathered a renewed interest in the field of tuberculosis as a structure that mimics some characteristics occurring during M. tuberculosis infection, such as antibiotic recalcitrance and chronicity of infection, and as a source of antigens for humoral response in infected guinea pigs. In other bacteria, it has been well documented that the second messenger c-di-GMP modulates the transition from planktonic cells to biofilm formation. In this work, we used the live vaccine Mycobacterium bovis BCG to determine whether deletion of genes involved in c-di-GMP metabolism would affect interaction with macrophages, capacity to induce immune response in a murine cell line and mice, and how the protein profile was modified when grown as surface pellicles...
March 14, 2018: Vaccine
Marc G J Feuilloley
By its size and diversity, the cutaneous microbial flora is the second of the human body and there is a growing body of research showing its key role in cutaneous homeostasis. However, skin is also the first neuroendocrine organ and it is now demonstrated that bacteria can sense a multitude of human hormones and neurotransmitters. Then, besides of the intrinsic effect of their virulence factors on cutaneous neurogenic activity, recent data demonstrate that the virulence, invasion potential, and biofilm formation activity of some of the principal species of the cutaneous bacteria flora are directly controlled by neuropeptides released by sensory nerve endings including substance P and calcitonin gene-related peptide...
March 16, 2018: Seminars in Immunopathology
Alejandro Avilés-Reyes, Irlan Almeida Freires, Richard Besingi, Sangeetha Purushotham, Champion Deivanayagam, L Jeannine Brady, Jacqueline Abranches, José A Lemos
Protein glycosylation has been described as the most abundant and complex post-translational modification occurring in nature. Recent studies have enhanced our view of how this modification occurs in bacteria highlighting the role of protein glycosylation in various processes such as biofilm formation, virulence and host-microbe interactions. We recently showed that the collagen- and laminin-binding adhesin Cnm of the dental pathogen Streptococcus mutans is post-translationally modified by the PgfS glycosyltransferase...
March 16, 2018: Scientific Reports
Olivier Poupel, Caroline Proux, Bernd Jagla, Tarek Msadek, Sarah Dubrac
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop...
March 2018: PLoS Pathogens
Arwa Abu Khweek, Amal O Amer
Legionella pneumophila ( L. pneumophila ) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems...
2018: Frontiers in Cellular and Infection Microbiology
Jin-Xin Zheng, Zhi-Wei Lin, Chen Chen, Zhong Chen, Fo-Jun Lin, Yang Wu, Si-Yu Yang, Xiang Sun, Wei-Ming Yao, Duo-Yun Li, Zhi-Jian Yu, Jia-Lin Jin, Di Qu, Qi-Wen Deng
Klebsiella pneumoniae bacteremia biofilm traits and distribution characteristics have not been clarified. This study aimed to determine the prevalence and characteristics of K. pneumoniae bacteremia biofilm formation (BF) and to explore the virulence factors associated with K. pneumoniae BF. A total of 250 K. pneumoniae bacteremia isolates were collected from patients in Shenzhen and Shanghai, China. Virulence genes in their genomes were detected by PCR. The isolates were subjected to multilocus sequence typing (MLST) and clonal complex (CC) classification based on housekeeping genes...
2018: Frontiers in Cellular and Infection Microbiology
Manmohit Kalia, Vivek Kumar Yadav, Pradeep Kumar Singh, Deepmala Sharma, Shahid Suhail Narvi, Vishnu Agarwal
AIMS: Pseudomonas aeruginosa is a well-known pathogen responsible for various infections due to its capability to develop biofilm and various virulent phenotypes that are regulated by quorum sensing. Pathogenesis of the bacteria may be halted by interfering with the signaling molecules and the quorum sensing receptors. Therefore, the present study explores the potential of parthenolide, a sesquiterpene lactone of feverfew plant, as a promising candidate against P. aeruginosa PAO1 associated virulence factors and biofilm...
March 7, 2018: Life Sciences
Alejandro Avilés-Reyes, Irlan Almeida Freires, Jessica K Kajfasz, Dicler Barbieri, James H Miller, José A Lemos, Jacqueline Abranches
We report the whole genome sequence (WGS) of the serotype e Cbm+ strain LAR01 of Streptococcus mutans, a dental pathogen frequently associated with extra-oral infections. The LAR01 genome is a single circular chromosome of 2.1 Mb with a GC content of 36.96%. The genome contains 15 PTS gene clusters, 7 cell wall-anchored (LPxTG) proteins, all genes required for the development of natural competence and genes coding for mutacins VI and K8. Interestingly, the cbm gene is genetically linked to a putative type VII secretion system that has been found in Mycobacteria and few other gram-positive bacteria...
March 9, 2018: Molecular Oral Microbiology
Benoit Couvigny, Saulius Kulakauskas, Nicolas Pons, Benoit Quinquis, Anne-Laure Abraham, Thierry Meylheuc, Christine Delorme, Pierre Renault, Romain Briandet, Nicolas Lapaque, Eric Guédon
Biofilm formation is crucial for bacterial community development and host colonization by Streptococcus salivarius , a pioneer colonizer and commensal bacterium of the human gastrointestinal tract. This ability to form biofilms depends on bacterial adhesion to host surfaces, and on the intercellular aggregation contributing to biofilm cohesiveness. Many S. salivarius isolates auto-aggregate, an adhesion process mediated by cell surface proteins. To gain an insight into the genetic factors of S. salivarius that dictate host adhesion and biofilm formation, we developed a screening method, based on the differential sedimentation of bacteria in semi-liquid conditions according to their auto-aggregation capacity, which allowed us to identify twelve mutations affecting this auto-aggregation phenotype...
2018: Frontiers in Microbiology
Meng-Ying Mao, Meng Li, Lei Lei, Jia-Xin Yin, Ying-Ming Yang, Tao Hu
Streptococcus mutans is an important factor in the etiology and pathogenesis of dental caries, largely owing to its ability to form a stable biofilm. Previous animal studies have indicated that rnc could decrease the amount of sulcal caries, and that the downregulation of cariogenicity might be due to its capacity to disrupt biofilm formation. However, the biofunctions by which rnc is involved in biofilm formation remain to be elucidated. In this study, we further investigate the role of rnc based on the study of mature biofilm...
March 6, 2018: Caries Research
Bruna Fuga Araújo, Melina Lorraine Ferreira, Paola Amaral de Campos, Sabrina Royer, Iara Rossi Gonçalves, Deivid William da Fonseca Batistão, Miriam Rodriguez Fernandes, Louise Teixeira Cerdeira, Cristiane Silveira de Brito, Nilton Lincopan, Paulo Pinto Gontijo-Filho, Rosineide Marques Ribas
In this study, we describe the frequency of virulence genes in Klebsiella pneumoniae carbapenemase-2-producing Klebsiella pneumoniae (KPC-KP), including hypervirulent (hv) and hypermucoviscous (hm) strains by whole-genome sequencing. We also evaluate the capacity for biofilm formation by using phenotypic techniques. The occurrence of several virulence genes (fimABCDEFGHIK, mrkABCDFHJ, ecpA, wabG, entB, ugE, irp1, irp2, traT, iutA and ureADE) and a high frequency of hvhmKPC-KP isolates was found. Most hospital-associated lineages of KPC-KP belong to the international clonal group 258 (CG258)...
March 6, 2018: Journal of Medical Microbiology
Yufei Wang, Xiuqing Wang, Wentao Jiang, Kun Wang, Junyuan Luo, Wei Li, Xuedong Zhou, Linglin Zhang
Cariogenic virulence factors of Streptococcus mutans include acidogenicity, aciduricity, and extracellular polysaccharides (EPS) synthesis. The de novo designed antimicrobial peptide GH12 has shown bactericidal effects on S. mutans , but its interaction with virulence and regulatory systems of S. mutans remains to be elucidated. The objectives were to investigate the effects of GH12 on virulence factors of S. mutans , and further explore the function mechanisms at enzymatic and transcriptional levels. To avoid decrease in bacterial viability, we limited GH12 to subinhibitory levels...
2018: Journal of Oral Microbiology
Mengmeng Zhang, Mengjia Wang, Xiaocui Zhu, Wengong Yu, Qianhong Gong
OBJECTIVE: To screen for the quorum-sensing (QS) inhibitors from marine-derived fungi and evaluate their anti-QS properties in Pseudomonas aeruginosa. RESULTS: QS inhibitory activity was found in secondary metabolites of a marine fungus Fusarium sp. Z10 using P. aeruginosa QSIS-lasI biosensor. The major active compound of this fungus was isolated by HPLC and identified as equisetin. Subinhibitory concentration of equisetin could inhibit the formation of biofilm, swarming motility, and the production of virulence factors in P...
March 3, 2018: Biotechnology Letters
Marilena Falcone, Silvia Ferrara, Elio Rossi, Helle K Johansen, Søren Molin, Giovanni Bertoni
The small RNA ErsA of Pseudomonas aeruginosa was previously suggested to be involved in biofilm formation via negative post-transcriptional regulation of the algC gene that encodes the virulence-associated enzyme AlgC, which provides sugar precursors for the synthesis of several polysaccharides. In this study, we show that a knock-out ersA mutant strain forms a flat and uniform biofilm, not characterized by mushroom-multicellular structures typical of a mature biofilm. Conversely, the knock-out mutant strain showed enhanced swarming and twitching motilities...
2018: Frontiers in Microbiology
Ankita Vaishampayan, Anne de Jong, Darren J Wight, Jan Kok, Elisabeth Grohmann
Methicillin-resistant Staphylococcus aureus (MRSA) has become an important cause of hospital-acquired infections worldwide. It is one of the most threatening pathogens due to its multi-drug resistance and strong biofilm-forming capacity. Thus, there is an urgent need for novel alternative strategies to combat bacterial infections. Recently, we demonstrated that a novel antimicrobial surface coating, AGXX® , consisting of micro-galvanic elements of the two noble metals, silver and ruthenium, surface-conditioned with ascorbic acid, efficiently inhibits MRSA growth...
2018: Frontiers in Microbiology
Ekaterina V Filippova, Bozena Zemaitaitis, Theint Aung, Alan J Wolfe, Wayne F Anderson
RcsB is a highly conserved transcription regulator of the Rcs phosphorelay system, a complex two-component signal transduction system (N. Majdalani and S. Gottesman, Annu Rev Microbiol 59:379-405, 2005; A. J. Wolfe, Curr Opin Microbiol 13:204-209, 2010,; D. J. Clarke, Future Microbiol 5:1173-1184, 2010, RcsB plays an important role in virulence and pathogenicity in human hosts by regulating biofilm formation. RcsB can regulate transcription alone or together with its auxiliary transcription regulators by forming heterodimers...
February 27, 2018: MBio
Brandon Sy, Julia Wong, Sander Granneman, David Tollervey, David Gally, Jai J Tree
Small regulatory nonprotein-coding RNAs (sRNAs) have emerged as ubiquitous and abundant regulators of gene expression in a diverse cross section of bacteria. They play key roles in most aspects of bacterial physiology, including central metabolism, nutrient acquisition, virulence, biofilm formation, and outer membrane composition. RNA sequencing technologies have accelerated the identification of bacterial regulatory RNAs and are now being employed to understand their functions. Many regulatory RNAs require protein partners for activity, or modulate the activity of interacting proteins...
2018: Methods in Molecular Biology
Zahra Farshadzadeh, Behrouz Taheri, Sara Rahimi, Saeed Shoja, Maryam Pourhajibagher, Mohammad A Haghighi, Abbas Bahador
Two different mechanisms of resistance to colistin in Acinetobacter baumannii have been described. The first involves the total loss of lipopolysaccharide (LPS) due to mutations in the lpxACD operon, which is involved in the lipid A biosynthesis pathway. The second entails the addition of ethanolamine to the lipid A of the LPS resulting from mutations in the PmrAB two-component system. To evaluate the impact of colistin resistance-associated mutations on antimicrobial resistance and virulence properties, four pairs of clinical and laboratory-evolved colistin-susceptible/colistin-resistant (ColS /ColR ) A...
2018: Frontiers in Microbiology
Xiayan Pan, Shu Xu, Jian Wu, Jianying Luo, Yabing Duan, Jianxin Wang, Feng Zhang, Mingguo Zhou
Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) and can be effectively controlled by phenazine-1-carboxylic acid (PCA), an antibiotic secreted by Pseudomonas spp. PCA resistance in Xoo was investigated in this research. Only four PCA-resistant strains were obtained by extensive screening, and the resistance was genetically stable in only one of them (P4). P4 was also resistant to phenazine and 1-hydroxyphezine but not to captan, bismerthiazol, or streptomycin. The following were reduced in P4 relative to the parental wild type: growth, virulence, EPS production, extracellular cellulase production and activity, biofilm formation, and swimming ability...
February 2018: Pesticide Biochemistry and Physiology
Debaprasad Parai, Malabika Banerjee, Pia Dey, Arindam Chakraborty, Ekramul Islam, Samir Kumar Mukherjee
This study aimed to evaluate the effect of reserpine, a plant-derived indole-alkaloid, against Pseudomonas aeruginosa PAO1 biofilms. The anti-biofilm activity of reserpine was evaluated by crystal violet staining, MTT assay, confocal laser scanning microscopy and scanning electron microscopy. Reserpine effects were also assessed by qRT-PCR of quorum sensing (QS)-regulated genes and biochemical quantification of the QS-mediated virulence factors pyocyanin, rhamnolipids, proteases and elastases. Reserpine reduced biofilm formation, cell motility, virulence factor production, and QS-controlled gene expression...
February 27, 2018: Biofouling
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