scholarly journals Molecular Characteristics of Streptococcus pyogenes Isolated From Chinese Children With Different Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Dingle Yu ◽  
Yunmei Liang ◽  
Qinghua Lu ◽  
Qing Meng ◽  
Wenjian Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Streptococcus Pyogenes ◽  
Wide Spectrum ◽  
Expression Patterns ◽  
Virulence Gene ◽  
High Rate ◽  
Molecular Characteristics ◽  
Virulence Gene Expression ◽  
Obstructive Sleep

Streptococcus pyogenes is a bacterial pathogen that causes a wide spectrum of clinical diseases exclusively in humans. The distribution of emm type, antibiotic resistance and virulence gene expression for S. pyogenes varies temporally and geographically, resulting in distinct disease spectra. In this study, we analyzed antibiotic resistance and resistance gene expression patterns among S. pyogenes isolates from pediatric patients in China and investigated the relationship between virulence gene expression, emm type, and disease categories. Forty-two representative emm1.0 and emm12.0 strains (n = 20 and n = 22, respectively) isolated from patients with scarlet fever or obstructive sleep apnea-hypopnea syndrome were subjected to whole-genome sequencing and phylogenetic analysis. These strains were further analyzed for susceptibility to vancomycin. We found a high rate and degree of resistance to macrolides and tetracycline in these strains, which mainly expressed ermB and tetM. The disease category correlated with emm type but not superantigens. The distribution of vanuG and virulence genes were associated with emm type. Previously reported important prophages, such as φHKU16.vir, φHKU488.vir, Φ5005.1, Φ5005.2, and Φ5005.3 encoding streptococcal toxin, and integrative conjugative elements (ICEs) such as ICE-emm12 and ICE-HKU397 encoding macrolide and tetracycline resistance were found present amongst emm1 or emm12 clones from Shenzhen, China.

scholarly journals Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in northeast China

2020 ◽  
Author(s):  
Yadong Sun ◽  
Shanshan Wen ◽  
Lili Zhao ◽  
Qiqi Xia ◽  
Yue Pan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Northeast China ◽  
Virulence Gene ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Virulence Gene Expression ◽  
Biofilm Production ◽  
High Level

Abstract Background The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016. Results Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in biofilm producers was significantly higher than that in non-producers. Biofilm production was significantly associated with the expression of ureC , zapA , rsmA , hmpA , mrpA , atfA , and pmfA ( P < 0.05). Drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin ( P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice ( P > 0.05). Conclusion Our findings suggested that a high level of multidrug resistance in diarrhetic animals infected with P. mirabilis in northeast China.The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.

scholarly journals Use of a Phosphorylation Site Mutant To Identify Distinct Modes of Gene Repression by the Control of Virulence Regulator (CovR) in Streptococcus pyogenes

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Nicola Horstmann ◽  
Pranoti Sahasrabhojane ◽  
Hui Yao ◽  
Xiaoping Su ◽  
Samuel A. Shelburne
Keyword(s):  
Gene Expression ◽  
Streptococcus Pyogenes ◽  
Response Regulator ◽  
Phosphorylation Site ◽  
Virulence Gene ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Superficial Skin ◽  
Virulence Regulator ◽  
The Impact

ABSTRACT Control of the virulence regulator/sensor kinase (CovRS) two-component system (TCS) serves as a model for investigating the impact of signaling pathways on the pathogenesis of Gram-positive bacteria. However, the molecular mechanisms by which CovR, an OmpR/PhoB family response regulator, controls virulence gene expression are poorly defined, partly due to the labile nature of its aspartate phosphorylation site. To better understand the regulatory effect of phosphorylated CovR, we generated the phosphorylation site mutant strain 10870-CovR-D53E, which we predicted to have a constitutive CovR phosphorylation phenotype. Interestingly, this strain showed CovR activity only for a subset of the CovR regulon, which allowed for classification of CovR-influenced genes into D53E-regulated and D53E-nonregulated groups. Inspection of the promoter sequences of genes belonging to each group revealed distinct promoter architectures with respect to the location and number of putative CovR-binding sites. Electrophoretic mobility shift analysis demonstrated that recombinant CovR-D53E protein retains its ability to bind promoter DNA from both CovR-D53E-regulated and -nonregulated groups, implying that factors other than mere DNA binding are crucial for gene regulation. In fact, we found that CovR-D53E is incapable of dimerization, a process thought to be critical to OmpR/PhoB family regulator function. Thus, our global analysis of CovR-D53E indicates dimerization-dependent and dimerization-independent modes of CovR-mediated repression, thereby establishing distinct mechanisms by which this critical regulator coordinates virulence gene expression. IMPORTANCE Streptococcus pyogenes causes a wide variety of diseases, ranging from superficial skin and throat infections to life-threatening invasive infections. To establish these various disease manifestations, Streptococcus pyogenes requires tightly coordinated production of its virulence factor repertoire. Here, the response regulator CovR plays a crucial role. As an OmpR/PhoB family member, CovR is activated by phosphorylation on a conserved aspartate residue, leading to protein dimerization and subsequent binding to operator sites. Our transcriptome analysis using the monomeric phosphorylation mimic mutant CovR-D53E broadens this general notion by revealing dimerization-independent repression of a subset of CovR-regulated genes. Combined with promoter analyses, these data suggest distinct mechanisms of CovR transcriptional control, which allow for differential expression of virulence genes in response to environmental cues.

scholarly journals DNA Adenine Methylation Regulates Virulence Gene Expression in Salmonella enterica Serovar Typhimurium

2006 ◽  
Vol 188 (23) ◽  
pp. 8160-8168 ◽  
Author(s):  
Roberto Balbontín ◽  
Gary Rowley ◽  
M. Graciela Pucciarelli ◽  
Javier López-Garrido ◽  
Yvette Wormstone ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salmonella Enterica ◽  
Expression Patterns ◽  
Virulence Gene ◽  
Luria Bertani ◽  
Altered Expression ◽  
Virulence Gene Expression ◽  
Adenine Methylation ◽  
Dam Methylation ◽  
Serovar Typhimurium

ABSTRACT Transcriptomic analyses during growth in Luria-Bertani medium were performed in strain SL1344 of Salmonella enterica serovar Typhimurium and in two isogenic derivatives lacking Dam methylase. More genes were repressed than were activated by Dam methylation (139 versus 37). Key genes that were differentially regulated by Dam methylation were verified independently. The largest classes of Dam-repressed genes included genes belonging to the SOS regulon, as previously described in Escherichia coli, and genes of the SOS-inducible Salmonella prophages ST64B, Gifsy-1, and Fels-2. Dam-dependent virulence-related genes were also identified. Invasion genes in pathogenicity island SPI-1 were activated by Dam methylation, while the fimbrial operon std was repressed by Dam methylation. Certain flagellar genes were repressed by Dam methylation, and Dam− mutants of S. enterica showed reduced motility. Altered expression patterns in the absence of Dam methylation were also found for the chemotaxis genes cheR (repressed by Dam) and STM3216 (activated by Dam) and for the Braun lipoprotein gene, lppB (activated by Dam). The requirement for DNA adenine methylation in the regulation of specific virulence genes suggests that certain defects of Salmonella Dam− mutants in the mouse model may be caused by altered patterns of gene expression.

scholarly journals Effect of Enterocins A and B on the Viability and Virulence Gene Expression of Listeria monocytogenes in Sliced Dry-Cured Ham

2021 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Aida Pérez-Baltar ◽  
Margarita Medina ◽  
Raquel Montiel
Keyword(s):  
Gene Expression ◽  
Listeria Monocytogenes ◽  
Expression Patterns ◽  
Meat Products ◽  
Virulence Gene ◽  
Virulence Gene Expression ◽  
Industrial Processing ◽  
Dry Cured Ham ◽  
Serotype 4B ◽  
The Impact

Dry-cured ham can be contaminated with Listeria monocytogenes during its industrial processing. The use of bacteriocins could ensure the safety of such meat products, but their effect on pathogen physiology is unknown. Therefore, the impact of enterocins A and B on the L. monocytogenes population, and the expression patterns of five genes (inlA, inlB, clpC, fbpA and prfA) related to adhesion/invasion and virulence regulation have been monitored in sliced dry-cured ham during 30 d of storage in refrigeration (4 °C) and temperature-abuse conditions (20 °C). L. monocytogenes strains S2 (serotype 1/2a) and S7-2 (serotype 4b) counts were reduced by 0.5 and 0.6 log units immediately after the application of enterocins A and B, a decrease lower than previously reported. Differences in gene expression were found between the two strains. For strain S2, expression tended to increase for almost all genes up to day seven of storage, whereas this increase was observed immediately after application for strain S7-2; however, overall gene expression was repressed from day one onwards, mainly under temperature-abuse conditions. L. monocytogenes strains investigated in the present work exhibited a mild sensitivity to enterocins A and B in sliced dry-cured ham. Bacteriocins caused changes in the expression patterns of virulence genes associated with adhesion and invasion, although the potential virulence of surviving cells was not enhanced.

scholarly journals Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in northeast China

2020 ◽  
Author(s):  
Yadong Sun ◽  
Shanshan Wen ◽  
Lili Zhao ◽  
Qiqi Xia ◽  
Yue Pan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Northeast China ◽  
Virulence Gene ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Virulence Gene Expression ◽  
Biofilm Production ◽  
High Level

Abstract Background The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016. Results Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in biofilm producers was significantly higher than that in non-producers. Biofilm production was significantly associated with the expression of ureC , zapA , rsmA , hmpA , mrpA , atfA , and pmfA ( P < 0.05). Drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin ( P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice ( P > 0.05). Conclusion Our findings suggested that a high level of multidrug resistance in diarrhetic animals infected with P. mirabilis in northeast China.The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.

scholarly journals Network rewiring: physiological consequences of reciprocally exchanging the physical locations and growth-phase-dependent expression patterns of the Salmonella fis and dps genes

2020 ◽  
Author(s):  
Marina M Bogue ◽  
Aalap Mogre ◽  
Michael C Beckett ◽  
Nicholas R Thomson ◽  
Charles J Dorman
Keyword(s):  
Gene Expression ◽  
Protein Binding ◽  
Stationary Phase ◽  
Growth Phase ◽  
Regulatory Network ◽  
Mammalian Cells ◽  
Expression Patterns ◽  
Virulence Gene ◽  
Exponential Phase ◽  
Virulence Gene Expression

ABSTRACTThe Fis nucleoid-associated protein controls the expression of a large and diverse regulon of genes in Gram-negative bacteria. Fis production is normally maximal in bacteria during the early exponential phase of batch culture growth, becoming almost undetectable by the onset of stationary phase. We tested the effect on the Fis regulatory network in Salmonella of moving the complete fis gene from its usual location near the origin of chromosomal replication to the position normally occupied by the dps gene in the Right macrodomain of the chromosome, and vice versa, creating the strain GX. In a parallel experiment, we tested the effect of rewiring the Fis regulatory network by placing the fis open reading frame under the control of the stationary-phase-activated dps promoter at the dps genetic location within Ter, and vice versa, creating the strain OX. ChIP-seq was used to measure global Fis protein binding and gene expression patterns. Strain GX showed few changes when compared with the wild type, although we did detect increased Fis binding at Ter, accompanied by reduced binding at Ori. Strain OX displayed a more pronounced version of this distorted Fis protein-binding pattern together with numerous alterations in the expression of genes in the Fis regulon. OX, but not GX, had a reduced ability to infect cultured mammalian cells. These findings illustrate the inherent robustness of the Fis regulatory network to rewiring based on gene repositioning alone and emphasise the importance of fis expression signals in phenotypic determination.IMPORTANCEWe assessed the impacts on Salmonella physiology of reciprocally translocating the genes encoding the Fis and Dps nucleoid-associated proteins (NAPs), and of inverting their growth phase production patterns such that Fis is produced in stationary phase (like Dps) and Dps is produced in exponential phase (like Fis). Changes to peak binding of Fis were detected by ChIP-seq on the chromosome, as were widespread impacts on the transcriptome, especially when Fis production mimicked Dps. Virulence gene expression and the expression of a virulence phenotype were altered. Overall, these radical changes to NAP gene expression were well tolerated, revealing the robust and well-buffered nature of global gene regulation networks in the bacterium.

scholarly journals Association among biofilm formation, virulence gene expression, and antibiotic resistance in Proteus mirabilis isolates from diarrhetic animals in northeast China

2019 ◽  
Author(s):  
Yadong Sun ◽  
Shanshan Wen ◽  
Lili Zhao ◽  
Qiqi Xia ◽  
Yue Pan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Northeast China ◽  
Virulence Gene ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Virulence Gene Expression ◽  
Biofilm Production ◽  
High Level

Abstract Background The aim of this study was to investigate the association among biofilm formation, virulence gene expression, and antibiotic resistance in P. mirabilis isolates collected from diarrhetic animals (n = 176) in northeast China between September 2014 and October 2016. Results Approximately 92.05% of the isolates were biofilm producers, whereas 7.95% of the isolates were non-producers. The prevalence of virulence genes in biofilm producers was significantly higher than that in non-producers. Biofilm production was significantly associated with the expression of ureC , zapA , rsmA , hmpA , mrpA , atfA , and pmfA ( P < 0.05). Drug susceptibility tests revealed that approximately 76.7% of the isolates were multidrug-resistant (MDR) and extensively drug-resistant (XDR). Biofilm production was significantly associated with resistance to doxycycline, tetracycline, sulfamethoxazole, kanamycin, and cephalothin ( P < 0.05). Although the pathogenicity of the biofilm producers was stronger than that of the non-producers, the biofilm-forming ability of the isolates was not significantly associated with morbidity and mortality in mice ( P > 0.05). Conclusion Our findings suggested that a high level of multidrug resistance in diarrhetic animals infected with P. mirabilis in northeast China.The results of this study indicated that the positive rates of the genes expressed by biofilm-producing P. mirabilis isolates were significantly higher than those expressed by non-producing isolates.

scholarly journals Swarming of Pseudomonas aeruginosa Is a Complex Adaptation Leading to Increased Production of Virulence Factors and Antibiotic Resistance

2008 ◽  
Vol 190 (8) ◽  
pp. 2671-2679 ◽  
Author(s):  
Joerg Overhage ◽  
Manjeet Bains ◽  
Michelle D. Brazas ◽  
Robert E. W. Hancock
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Leading Edge ◽  
Adaptation Process ◽  
Extracellular Proteases ◽  
Swarming Motility ◽  
Virulence Gene Expression

ABSTRACT In addition to exhibiting swimming and twitching motility, Pseudomonas aeruginosa is able to swarm on semisolid (viscous) surfaces. Recent studies have indicated that swarming is a more complex type of motility influenced by a large number of different genes. To investigate the adaptation process involved in swarming motility, gene expression profiles were analyzed by performing microarrays on bacteria from the leading edge of a swarm zone compared to bacteria growing in identical medium under swimming conditions. Major shifts in gene expression patterns were observed under swarming conditions, including, among others, the overexpression of a large number of virulence-related genes such as those encoding the type III secretion system and its effectors, those encoding extracellular proteases, and those associated with iron transport. In addition, swarming cells exhibited adaptive antibiotic resistance against polymyxin B, gentamicin, and ciprofloxacin compared to what was seen for their planktonic (swimming) counterparts. By analyzing a large subset of up-regulated genes, we were able to show that two virulence genes, lasB and pvdQ, were required for swarming motility. These results clearly favored the conclusion that swarming of P. aeruginosa is a complex adaptation process in response to a viscous environment resulting in a substantial change in virulence gene expression and antibiotic resistance.

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