keyword
MENU ▼
Read by QxMD icon Read
search

Small colony variant

keyword
https://www.readbyqxmd.com/read/29250041/stenotrophomonas-maltophilia-as-an-emerging-ubiquitous-pathogen-looking-beyond-contemporary-antibiotic-therapy
#1
REVIEW
Anthony A Adegoke, Thor A Stenström, Anthony I Okoh
Stenotrophomonas maltophilia is a commensal and an emerging pathogen earlier noted in broad-spectrum life threatening infections among the vulnerable, but more recently as a pathogen in immunocompetent individuals. The bacteria are consistently being implicated in necrotizing otitis, cutaneous infections including soft tissue infection and keratitis, endocarditis, meningitis, acute respiratory tract infection (RTI), bacteraemia (with/without hematological malignancies), tropical pyomyositis, cystic fibrosis, septic arthritis, among others...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29247687/genotypic-variations-between-wild-type-and-small-colony-variants-of-staphylococcus-aureus-in-prosthetic-valve-infectious-endocarditis-a-comparative-genomic-and-transcriptomic-analysis
#2
Hongbin Chen, Qi Wang, Yuyao Yin, Shuguang Li, Deng-Ke Niu, Hui Wang
Staphylococcus aureus small colony variants (SCVs) can cause persistent infections. However, the genomes and transcriptomes of S. aureus SCVs remain poorly understood. We isolated a pair of isogenic wild-type and SCV methicillin-resistant S. aureus (MRSA) strains (IE1 and IE2, respectively) from a patient with prosthetic valve infectious endocarditis. The SCV IE2 strain grew more slowly than the wild-type strain, and serum killing and mouse lethality assays revealed that the virulence of the SCV strain IE2 was decreased...
December 13, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/29247337/microbial-contamination-of-smartphone-touchscreens-of-italian-university-students
#3
Silvia Di Lodovico, Angela Del Vecchio, Valentina Cataldi, Emanuela Di Campli, Soraya Di Bartolomeo, Luigina Cellini, Mara Di Giulio
In this study, the microbial contamination of smartphones from Italian University students was analyzed. A total of 100 smartphones classified as low, medium, and high emission were examined. Bacteria were isolated on elective and selective media and identified by biochemical tests. The mean values of cfu/cm2 were 0.79 ± 0.01; in particular, a mean of 1.21 ± 0.12, 0.77 ± 0.1 and 0.40 ± 0.10 cfu/cm2 was present on smartphones at low, medium, and high emission, respectively. The vast majority of identified microorganisms came from human skin, mainly Staphylococci, together with Gram-negative and positive bacilli and yeasts...
December 15, 2017: Current Microbiology
https://www.readbyqxmd.com/read/29242387/inbred-or-outbred-genetic-diversity-in-laboratory-rodent-colonies
#4
Thomas D Brekke, Katherine A Steele, John F Mulley
Non-model rodents are widely used as subjects for both basic and applied biological research, but the genetic diversity of the study individuals is rarely quantified. University-housed colonies tend to be small and subject to founder effects and genetic drift and so may be highly inbred or show substantial genetic divergence from other colonies, even those derived from the same source. Disregard for the levels of genetic diversity in an animal colony may result in a failure to replicate results if a different colony is used to repeat an experiment, as different colonies may have fixed alternative variants...
December 13, 2017: G3: Genes—Genomes—Genetics
https://www.readbyqxmd.com/read/29211886/bicarbonate-induces-high-level-resistance-to-the-human-antimicrobial-peptide-ll-37-in-staphylococcus-aureus-small-colony-variants
#5
Ping Zhang, John A Wright, Anna Tymon, Sean P Nair
Objectives: Staphylococcus aureus small colony variants (SCVs) cause persistent infections and are resistant to cationic antibiotics. Antimicrobial peptides (AMPs) have been suggested as promising alternatives for treating antibiotic-resistant bacteria. We investigated the capacity of the human cationic AMP LL-37 to kill SCVs in the presence of physiological concentrations of bicarbonate, which are reported to alter bacterial membrane permeability and change resistance of bacteria to AMPs...
December 4, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29205135/a-hemin-auxotrophic-enterobacter-cloacae-clinical-isolate-with-increased-resistance-to-carbapenems-and-aminoglycosides
#6
Tatsuya Tada, Kohei Uechi, Isamu Nakasone, Zenji Miyazato, Takashi Shinzato, Kayo Shimada, Mitsuhiro Tsuchiya, Teruo Kirikae, Jiro Fujita
Small-colony variants (SCVs) were obtained from an Enterobacter cloacae clinical isolate in Okinawa, Japan. One variant showed auxotrophy for hemin with a deletion of 20 365 nucleotides, dosC-ydiK-mmuP-mmuM-tauA-tauB-tauC-tauD-hemB-yaiT-yaiV-ampH-yddQ-sbmA-yaiW-yaiY-yaiZ, including hemB, and was more resistant to aminoglycosides and carbapenems, but more susceptible to aztreonam, than the parent strain.
December 5, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/29157814/mistletoe-viscum-album-extract-targets-axl-to-suppress-cell-proliferation-and-overcome-cisplatin-and-erlotinib-resistance-in-non-small-cell-lung-cancer-cells
#7
Soyoung Kim, Kyung-Chan Kim, ChuHee Lee
BACKGROUND: Mistletoe extract of Visucm album extract (VAE) contains many biologically active components and has been reported to be not only a complementary and alternative medicine, but also a potent therapeutic agent for many types of cancer. PURPOSE: In this study, we examined the effect of VAE on expression and activation of Axl and scrutinized the involvement of Axl in the anti-cancer activity of VAE in parental and chemo-resistant non-small cell lung cancer (NSCLC) cells...
December 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/29150501/glna-truncation-in-salmonella-enterica-results-in-a-small-colony-variant-phenotype-attenuated-host-cell-entry-and-reduced-expression-of-flagellin-and-spi-1-associated-effector-genes
#8
Philipp Aurass, Juliane Düvel, Susanne Karste, Ulrich Nübel, Wolfgang Rabsch, Antje Flieger
Many pathogenic bacteria use sophisticated survival strategies to overcome harsh environmental conditions. One is the formation of slow-growing subpopulations termed small colony variants (SCVs). Here we characterize an SCV, which spontaneously emerged from an axenic Salmonella enterica serovar Typhimurium water culture. We found that the SCV harbors a frameshift mutation in the glutamine synthetase gene glnA leading to a ∼90% truncation of the corresponding protein. Glutamine synthetase, a central enzyme in nitrogen assimilation, converts glutamate and ammonia to glutamine...
November 17, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29143727/characterization-of-clinically-isolated-thymidine-dependent-small-colony-variants-of-escherichia-coli-producing-extended-spectrum-%C3%AE-lactamase
#9
Tatsuya Negishi, Takehisa Matsumoto, Kazuki Horiuchi, Eriko Kasuga, Tatsuya Natori, Mina Matsuoka, Naoko Ogiwara, Mitsutoshi Sugano, Takeshi Uehara, Noriyuki Nagano, Takayuki Honda
PURPOSE: Thymidine-dependent small-colony variants (TD-SCVs) are difficult to detect or test for antimicrobial susceptibility. We investigated the characteristics of clonal TD-SCVs of Escherichia coli, both with and without blaCTX-M-3, isolated from a patient. METHODOLOGY: Mutation in the thyA gene was analysed by sequencing, and morphological abnormalities in the colonies and cells of the isolates were examined. Additionally, conjugational transfer experiments were performed to prove the horizontal transferability of plasmids harbouring resistance genes...
November 16, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/29130165/biosensors-for-the-detection-and-quantification-of-ai-2-class-quorum-sensing-compounds
#10
Sathish Rajamani, Richard Sayre
Intercellular small-molecular-weight signaling molecules modulate a variety of biological functions in bacteria. One of the more complex behaviors mediated by intercellular signaling molecules is the suite of activities regulated by quorum-sensing molecules. These molecules mediate a variety of population-dependent responses including the expression of genes that regulate bioluminescence, type III secretion, siderophore production, colony morphology, biofilm formation, and metalloprotease production. Given their central role in regulating these responses, the detection and quantification of QS molecules have important practical implications...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29034850/pseudomonas-aeruginosa-variants-obtained-from-veterinary-clinical-samples-reveal-a-role-for-cyclic-di-gmp-in-biofilm-formation-and-colony-morphology
#11
Maria T Brock, Galya C Fedderly, Grace I Borlee, Michael M Russell, Liliana K Filipowska, Doreene R Hyatt, Ryan A Ferris, Bradley R Borlee
Overuse of antibiotics is contributing to an emerging antimicrobial resistance crisis. To better understand how bacteria adapt tolerance and resist antibiotic treatment, Pseudomonas aeruginosa isolates obtained from infection sites sampled from companion animals were collected and evaluated for phenotypic differences. Selected pairs of clonal isolates were obtained from individual infection samples and were assessed for antibiotic susceptibility, cyclic di-GMP levels, biofilm production, motility and genetic-relatedness...
October 16, 2017: Microbiology
https://www.readbyqxmd.com/read/28993457/the-electron-transport-chain-sensitises-staphylococcus-aureus-and-enterococcus-faecalis-to-the-oxidative-burst
#12
Kimberley L Painter, Alex Hall, Kam Pou Ha, Andrew M Edwards
Small colony variants (SCVs) of Staphylococcus aureus typically lack a functional electron transport chain and cannot produce virulence factors such as leukocidins, hemolysins or the anti-oxidant staphyloxanthin. Despite this, SCVs are associated with persistent infections of the bloodstream, bones and prosthetic devices. The survival of SCVs in the host has been ascribed to intracellular residency, biofilm formation and resistance to antibiotics. However, the ability of SCVs to resist host defences is largely uncharacterised...
October 9, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28987343/comparison-of-gene-co-expression-networks-in-pseudomonas-aeruginosa-and-staphylococcus-aureus-reveals-conservation-in-some-aspects-of-virulence
#13
Nazanin Hosseinkhan, Zaynab Mousavian, Ali Masoudi-Nejad
Pseudomonas aeruginosa and Staphylococcus aureus are two evolutionary distant bacterial species that are frequently isolated from persistent infections such as chronic infectious wounds and severe lung infections in cystic fibrosis patients. To the best of our knowledge no comprehensive genome scale co-expression study has been already conducted on these two species and in most cases only the expression of very few genes has been the subject of investigation. In this study, in order to investigate the level of expressional conservation between these two species, using heterogeneous gene expression datasets the weighted gene co-expression network analysis (WGCNA) approach was applied to study both single and cross species genome scale co-expression patterns of these two species...
October 4, 2017: Gene
https://www.readbyqxmd.com/read/28943172/staphylococcus-lugdunensis-small-colony-variant-conversion-resulting-in-chronic-prosthetic-joint-infection
#14
X Argemi, S Dahyot, J Lebeurre, Y Hansmann, C Ronde Oustau, G Prévost
No abstract text is available yet for this article.
November 2017: Médecine et Maladies Infectieuses
https://www.readbyqxmd.com/read/28915357/a-yigp-mutant-strain-is-a-small-colony-variant-of-e-coli-and-shows-pleiotropic-antibiotic-resistance
#15
Hui Xia, Qiongwei Tang, Jie Song, Jiang Ye, Haizhen Wu, Huizhan Zhang
Small colony variants (SCVs) are a commonly observed subpopulation of bacteria that have a small colony size and distinctive biochemical characteristics. SCVs are more resistant than the wild type to some antibiotics and usually cause persistent infections in the clinic. SCV studies have been very active during the past 2 decades, especially Staphylococcus aureus SCVs. However, fewer studies on Escherichia coli SCVs exist, so we studied an E. coli SCV during an experiment involving the deletion of the yigP locus...
September 15, 2017: Canadian Journal of Microbiology
https://www.readbyqxmd.com/read/28874369/transcriptional-and-mutational-profiling-of-an-aminoglycoside-resistant-pseudomonas-aeruginosa-small-colony-variant
#16
Monika Schniederjans, Michal Koska, Susanne Häussler
Pseudomonas aeruginosa is a major causative agent of both acute and chronic infections. Although aminoglycoside antibiotics are very potent drugs against such infections, antibiotic failure is steadily increasing mainly because of increasing resistance of the bacteria. Many molecular mechanisms that determine resistance, such as acquisition of genes encoding aminoglycoside-inactivating enzymes or overexpression of efflux pumps, have been elucidated. However, there are additional, less well-described mechanisms of aminoglycoside resistance...
November 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28859444/evaluation-of-combinations-of-putative-anti-biofilm-agents-and-antibiotics-to-eradicate-biofilms-of-staphylococcus-aureus-and-pseudomonas-aeruginosa
#17
Katherine Belfield, Roger Bayston, Nadzieja Hajduk, Georgia Levell, John P Birchall, Matija Daniel
Objectives: To evaluate potential anti-biofilm agents for their ability to enhance the activity of antibiotics for local treatment of localized biofilm infections. Methods: Staphylococcus aureus and Pseudomonas aeruginosa in vitro biofilm models were developed. The putative antibiotic enhancers N-acetylcysteine, acetylsalicylic acid, sodium salicylate, recombinant human deoxyribonuclease I, dispersin B, hydrogen peroxide and Johnson's Baby Shampoo (JBS) were tested for their anti-biofilm activity alone and their ability to enhance the activity of antibiotics for 7 or 14 days, against 5 day old biofilms...
September 1, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28845425/having-your-cake-and-eating-it-staphylococcus-aureus-small-colony-variants-can-evolve-faster-growth-rate-without-losing-their-antibiotic-resistance
#18
COMMENT
Gerrit Brandis, Sha Cao, Douglas L Huseby, Diarmaid Hughes
Staphylococcus aureus can produce small colony variants (SCVs) during infections. These cause significant clinical problems because they are difficult to detect in standard microbiological screening and are associated with persistent infections. The major causes of the SCV phenotype are mutations that inhibit respiration by inactivation of genes of the menadione or hemin biosynthesis pathways. This reduces the production of ATP required to support fast growth. Importantly, it also decreases cross-membrane potential in SCVs, resulting in decreased uptake of cationic compounds, with reduced susceptibility to aminoglycoside antibiotics as a consequence...
August 1, 2017: Microbial Cell
https://www.readbyqxmd.com/read/28843820/multiple-paths-towards-reduced-membrane-potential-and-concomitant-reduction-in-aminoglycoside-susceptibility-in-staphylococcus-aureus
#19
Martin Vestergaard, Katrine Nøhr-Meldgaard, Hanne Ingmer
Staphylococcus aureus confers life-threatening and difficult to treat infections worldwide and antimicrobial resistance is an increasing concern. While acquired resistance has been widely studied, little is known of the contributions from chromosomal determinants that upon inactivation may reduce the susceptibility towards antibiotics. The aim of this study was to identify genetic determinants that upon inactivation reduce aminoglycoside susceptibility in Staphylococcus aureus. We screened the Nebraska Transposon Mutant Library of 1920 single-gene inactivations in S...
August 23, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28820897/persistent-infection-due-to-a-small-colony-variant-of-burkholderia-pseudomallei-leads-to-pd-1-upregulation-on-circulating-immune-cells-and-mononuclear-infiltration-in-viscera-of-experimental-balb-c-mice
#20
Jia-Xiang See, Samudi Chandramathi, Mahmood Ameen Abdulla, Jamuna Vadivelu, Esaki M Shankar
BACKGROUND: Melioidosis is a neglected tropical disease endemic across South East Asia and Northern Australia. The etiological agent, Burkholderia pseudomallei (B.pseudomallei), is a Gram-negative, rod-shaped, motile bacterium residing in the soil and muddy water across endemic regions of the tropical world. The bacterium is known to cause persistent infections by remaining latent within host cells for prolonged duration. Reactivation of the recrudescent disease often occurs in elders whose immunity wanes...
August 2017: PLoS Neglected Tropical Diseases
keyword
keyword
117473
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"