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virulence genes and biofilm formation

Ranjith Rajendran, Ali May, Leighann Sherry, Ryan Kean, Craig Williams, Brian L Jones, Karl V Burgess, Jaap Heringa, Sanne Abeln, Bernd W Brandt, Carol A Munro, Gordon Ramage
Candida albicans biofilm formation is an important virulence factor in the pathogenesis of disease, a characteristic which has been shown to be heterogeneous in clinical isolates. Using an unbiased computational approach we investigated the central metabolic pathways driving biofilm heterogeneity. Transcripts from high (HBF) and low (LBF) biofilm forming isolates were analysed by RNA sequencing, with 6312 genes identified to be expressed in these two phenotypes. With a dedicated computational approach we identified and validated a significantly differentially expressed subnetwork of genes associated with these biofilm phenotypes...
October 21, 2016: Scientific Reports
Ahmed Abdel Megeed, M Ali Hayssam, Mohamed Z M Salem, Mohamed S El-Shikh, Ibrahim Ahmed Talea, Yahya A Alogaibi
Multidrug-resistant (MDR) Acinetobacter baumannii infections are a great public health concern and demand continuous surveillance and antibiotic stewardship. Virulence traits and the pathogenicity of Acinetobacter are less studied compared with the molecular epidemiological and antibiotic resistance profile of this organism. In our present study, we investigated the primary characteristics contributing to the virulence of MDR A. baumannii isolates and compared them with avirulent isolates. A total of 32 well-characterized MDR A...
October 19, 2016: Journal of AOAC International
Wei Qiu, Biao Ren, Huanqin Dai, Lixin Zhang, Qiong Zhang, Xuedong Zhou, Yuqing Li
OBJECTIVE: The aim of this study was to determine the inhibitory effect of eight antifungal drugs on S. mutans growth, biofilm formation and virulence factors. METHODS: The actions of antifungal drugs on S. mutans were determined by recovery plates and survival kinetic curves. Biofilms were observed by scanning electron microscopy and the viable cells were recovered on BHI plates, meanwhile biofilms were stained by BacLight live/dead kit to investigate the biofilm viability...
October 13, 2016: Archives of Oral Biology
Julia I Tandberg, Leidy X Lagos, Petter Langlete, Eva Berger, Anne-Lise Rishovd, Norbert Roos, Deepa Varkey, Ian T Paulsen, Hanne C Winther-Larsen
Membrane vesicles (MVs) are spherical particles naturally released from the membrane of Gram-negative bacteria. Bacterial MV production is associated with a range of phenotypes including biofilm formation, horizontal gene transfer, toxin delivery, modulation of host immune responses and virulence. This study reports comparative profiling of MVs from bacterial strains isolated from three widely disperse geographical areas. Mass spectrometry identified 119, 159 and 142 proteins in MVs from three different strains of Piscirickettsia salmonis isolated from salmonids in Chile (LF-89), Norway (NVI 5692) and Canada (NVI 5892), respectively...
2016: PloS One
Xingxing Dong, Xiaohong Wang, Xingchun Chen, Zhiyun Yan, Jing Cheng, Liangliang Gao, Yuan Liu, Jinquan Li
Staphylococcus aureus, a commensal and a pathogenic bacterium, causes a wide variety of diseases in humans and animals with a high impact on public health and the livestock industry. The risk of zoonotic transmission to humans highlights the need to understand the molecular ecology of S. aureus in foods. In this study, we obtained 25 S. aureus isolates from 39 crayfish samples in Hubei, China. PCR was applied for detection of presence of virulence and methicillin resistance genes in the pathogen genome. The result revealed that all of the 25 S...
October 19, 2016: Current Microbiology
Dharmaprakash Viszwapriya, Ganapathy Ashwinkumar Subramenium, Solai Radhika, Shunmugiah Karutha Pandian
Streptococcus mutans, a multivirulent pathogen is considered the primary etiological agent in dental caries. Development of antibiotic resistance in the pathogen has created a need for novel antagonistic agents which can control the virulence of the organism and reduce resistance development. The present study demonstrates the in vitro anti-virulence potential of betulin (lup-20(29)-ene-3β,28-diol), an abundantly available plant triterpenoid against S. mutans UA159. Betulin exhibited significant dose dependent antibiofilm activity without affecting bacterial viability...
October 18, 2016: Antonie Van Leeuwenhoek
S S Garcia, Q Du, H Wu
The oral cavity is a dynamic environment characterized by hundreds of bacterial species, saliva, and an influx of nutrients and metal ions such as copper. Although there is a physiologic level of copper in the saliva, the oral cavity is often challenged with an influx of copper ions. At high concentrations copper is toxic and must therefore be strictly regulated by pathogens for them to persist and cause disease. The cariogenic pathogen Streptococcus mutans manages excess copper using the copYAZ operon that encodes a negative DNA-binding repressor (CopY), the P1-ATPase copper exporter (CopA), and the copper chaperone (CopZ)...
December 21, 2015: Molecular Oral Microbiology
Zahid Iqbal, Mohamed N Seleem, Hafiz Iftikhar Hussain, Lingli Huang, Haihong Hao, Zonghui Yuan
Several studies have been conducted to check the prevalence of methicillin-resistant strains of Staphylococcus aureus (MRSA) in animals and animal-derived food products but limited data are available regarding their virulence and associated gene expression profile. In the present study, antibiotic resistance and virulence of MRSA and methicillin-sensitive S. aureus animal isolates were determined in vitro by agar dilution, biofilm formation, adhesion, invasion and intracellular survivability assays. In addition, the pathogenicity of these isolates was examined in a murine model of S...
October 14, 2016: Scientific Reports
Awa R N'Diaye, Camille Leclerc, Takfarinas Kentache, Julie Hardouin, Cecile Duclairoir Poc, Yoan Konto-Ghiorghi, Sylvie Chevalier, Olivier Lesouhaitier, Marc G J Feuilloley
Staphylococci can sense Substance P (SP) in skin, but this molecule is generally released by nerve terminals along with another neuropeptide, Calcitonin Gene Related Peptide (CGRP). In this study, we investigated the effects of αCGRP on Staphylococci. CGRP induced a strong stimulation of Staphylococcus epidermidis virulence with a low threshold (<10(-12 )M) whereas Staphylococcus aureus was insensitive to CGRP. We observed that CGRP-treated S. epidermidis induced interleukin 8 release by keratinocytes...
October 14, 2016: Scientific Reports
Kannan Rama Devi, Ramanathan Srinivasan, Arunachalam Kannappan, Sivasubramanian Santhakumari, Murugan Bhuvaneswari, Periyannan Rajasekar, Narayanan Marimuthu Prabhu, Arumugam Veera Ravi
Rosmarinic acid (RA) was assessed for its quorum sensing inhibitory (QSI) potential against Aeromonas hydrophila strains AH 1, AH 12 and MTCC 1739. The pathogenic strains of A. hydrophila were isolated from infected zebrafish and identified through biochemical analysis and amplification of a species-specific gene (rpsL). The biofilm inhibitory concentration (BIC) of RA against A. hydrophila strains was found to be 750 μg ml(-1). At this concentration, RA reduced the QS mediated hemolysin, lipase and elastase production in A...
November 2016: Biofouling
S J Kaiser, N T Mutters, A DeRosa, C Ewers, U Frank, F Günther
Pseudomonas aeruginosa (Pa) is one of the major bacterial pathogens causing nosocomial infections. During the past few decades, multidrug-resistant (MDR) and extensively drug-resistant (XDR) lineages of Pa have emerged in hospital settings with increasing numbers. However, it remains unclear which determinants of Pa facilitated this spread. A total of 211 clinical XDR and 38 susceptible clinical Pa isolates (nonXDR), as well as 47 environmental isolates (EI), were collected at the Heidelberg University Hospital...
October 12, 2016: European Journal of Clinical Microbiology & Infectious Diseases
Vandana Sharma, Rajaram Purushotham, Rupinder Kaur
The phosphoinositide 3-kinase (PI3K), which phosphorylates phosphatidylinositol and produces PI3P, has been implicated in protein trafficking, intracellular survival and virulence in the pathogenic yeast Candida glabrata Here, we demonstrate PI3-kinase (CgVps34) to be essential for maintenance of cellular iron homeostasis. We examine how CgVps34 regulates the fundamental process of iron acquisition, and underscore its function in vesicular trafficking as a central determinant. RNA-sequencing analysis revealed iron homeostasis genes to be differentially expressed upon CgVps34 disruption...
October 11, 2016: Journal of Biological Chemistry
Felipe de Camargo Ribeiro, Patricia Pimentel de Barros, Rodnei Dennis Rossoni, Juliana Campos Junqueira, Antonio Olavo Cardoso Jorge
AIM: The aim of this study was to evaluate the potential anti-Candida effects of Lactobacillus rhamnosus ATCC 9595 on C. albicans ATCC 18804 using in vitro and in vivo models. METHODS AND RESULTS: The in vitro analysis evaluated the effects of L. rhamnosus on C. albicans's biofilm formation by CFU count and metabolic activity, filamentation capacity, and adhesion (ALS3 and HWP1) and transcriptional regulatory gene (BCR1 and CPH1) expression. The in vitro results showed that both the L...
October 11, 2016: Journal of Applied Microbiology
Helena Pillich, Madhu Puri, Trinad Chakraborty
Listeria monocytogenes is a ubiquitously occurring gram-positive bacterium in the environment that causes listeriosis, one of the deadliest foodborne infections known today. It is a versatile facultative intracellular pathogen capable of growth within the host's cytosolic compartment. Following entry into the host cell, L. monocytogenes escapes from vacuolar compartments to the cytosol, where the bacterium begins a remarkable journey within the host cytoplasm, culminating in bacterial spread from cell to cell, to deeper tissues and organs...
September 21, 2016: Current Topics in Microbiology and Immunology
Yanping Han, Haihong Fang, Lei Liu, Dongsheng Zhou
Y. pestis exhibits dramatically different traits of pathogenicity and transmission, albeit their close genetic relationship with its ancestor-Y. pseudotuberculosis, a self-limiting gastroenteric pathogen. Y. pestis is evolved into a deadly pathogen and transmitted to mammals and/or human beings by infected flea biting or directly contacting with the infected animals. Various kinds of environmental changes are implicated into its complex life cycle and pathogenesis. Dynamic regulation of gene expression is critical for environmental adaptation or survival, primarily reflected by genetic regulation mediated by transcriptional factors and small regulatory RNAs at the transcriptional and posttranscriptional level, respectively...
2016: Advances in Experimental Medicine and Biology
Zongmin Du, Xiaoyi Wang
Various types of animal models of plague have been developed, including mice, rats, guinea pigs, and nonhuman primates. Studies have indicated that rodent and nonhuman primate models of pneumonic plague closely resemble the human disease and that the pathologic changes that occur during bubonic plague are very similar in rodents, nonhuman primates, and humans. In this section, the pathological changes caused by Y. pestis in different animal models are described. The bacterium Y. pestis causes deadly plague, whereas the other two closely related enteropathogenic Yersinia species merely cause limited gastrointestinal manifestations...
2016: Advances in Experimental Medicine and Biology
Ramanathan Srinivasan, Kannan Rama Devi, Arunachalam Kannappan, Shunmugiah Karutha Pandian, Arumugam Veera Ravi
ETHNOPHARMACOLOGICAL RELEVANCE: Piper betle, a tropical creeper plant belongs to the family Piperaceae. The leaves of this plant have been well known for their therapeutic, religious and ceremonial value in South and Southeast Asia. It has also been reported to possess several biological activities including antimicrobial, antioxidant, antinociceptive, antidiabetic, insecticidal and gastroprotective activities and used as a common ingredient in indigenous medicines. In Indian system of ayurvedic medicine, P...
October 6, 2016: Journal of Ethnopharmacology
Hung King Tiong, Peter M Muriana
L. monocytogenes adherence to food-associated abiotic surfaces and the development of biofilms as one of the underlying reasons for the contamination of ready-to-eat products is well known. The over-expression of internalins that improves adherence has been noted in cells growing as attached cells or at elevated incubation temperatures. However, the role of other internalin-independent surface proteins as adhesins has been uncharacterized to date. Using two strains each of weakly- and strongly-adherent L. monocytogenes as platforms for temperature-dependent adherence assays and targeted mRNA analyses, these observations (i...
October 1, 2016: Pathogens
Xiaohui Xu, Hua Yu, Di Zhang, Junzhi Xiong, Jing Qiu, Rong Xin, Xiaomei He, Halei Sheng, Wenqiang Cai, Lu Jiang, Kebin Zhang, Xiaomei Hu
During infection, bacteria might generate adaptive responses to facilitate their survival and colonization in the host environment. The alarmone guanosine 5'-triphosphate-3'-diphosphate (ppGpp), the levels of which are regulated by the RelA and SpoT enzymes, plays a critical role in mediating bacterial adaptive responses and virulence. However, the mechanism by which ppGpp regulates virulence-associated traits in Pseudomonas aeruginosa is poorly understood. To investigate the regulatory role of ppGpp, the ppGpp-deficient strain ΔRS (relA and spoT gene double mutant) and the complemented strain ΔRS(++) (complemented with relA and spoT genes) were constructed...
November 2016: Microbiological Research
Cen Jiang, Zhen Li, Lihua Zhang, Yuan Tian, Danfeng Dong, Yibing Peng
Recently, the proportion of Candida tropicalis in clinical isolates has significantly increased. Some C. tropicalis strains colonize the skin or mucosal surfaces as commensals; others trigger invasive infection. To date, the pathogenicity of C. tropicalis has not been thoroughly researched. This study reports several virulence factors, including biofilm and hyphae formation, proteinase, phospholipase, lipase and hemolytic activity, in 52 clinical isolates of C. tropicalis collected from five hospitals in four provinces of China...
November 2016: Microbiological Research
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