Superantigen profiles of emm and emm-like typeable and nontypeable pharyngeal streptococcal isolates of South India

<p>Abstract</p> <p>Background</p> <p>The major virulence factors determining the pathogenicity of streptococcal strains include M protein encoded by <it>emm </it>and <it>emm</it>-like (<it>emmL</it>) genes and superantigens. In this study, the distribution of <it>emm, emmL </it>and superantigen genes was analyzed among the streptococcal strains isolated from the patients of acute pharyngitis.</p> <p>Methods</p> <p>The streptococcal strains were isolated from the throat swabs of 1040 patients of acute pharyngitis. The <it>emm </it>and <it>emmL </it>genes were PCR amplified from each strain and sequenced to determine the <it>emm </it>types. The dot-blot hybridization was performed to confirm the pathogens as true <it>emm </it>nontypeable strains. The presence of eleven currently known superantigens was determined in all the strains by multiplex PCR.</p> <p>Results</p> <p>Totally, 124 beta-hemolytic streptococcal strains were isolated and they were classified as group A streptococcus (GAS) [15.3% (19/124)], group C streptococcus (GCS) [59.7% (74/124)] and group G streptococcus (GGS) [25.0% (31/124)]. Among 124 strains, only 35 strains were <it>emm </it>typeable and the remaining 89 strains were <it>emm </it>nontypeable. All GAS isolates were typeable, whereas most of the GCS and GGS strains were nontypeable. These nontypeable strains belong to <it>S. anginosus </it>[75.3% (67/89)] and <it>S. dysgalactiae </it>subsp. <it>equisimilis </it>[24.7% (22/89)]. The <it>emm </it>and <it>emmL </it>types identified in this study include <it>emm12.0 </it>(28.6%), <it>stG643.0 </it>(28.6%), <it>stC46.0 </it>(17.0%), <it>emm30.11 </it>(8.5%), <it>emm3.0 </it>(2.9%), <it>emm48.0 </it>(5.7%), <it>st3343.0 </it>(2.9%), <it>emm107.0 </it>(2.9%) and <it>stS104.2 </it>(2.9%). Various superantigen profiles were observed in typeable as well as nontypeable strains.</p> <p>Conclusions</p> <p>Multiplex PCR analysis revealed the presence of superantigens in all the typeable strains irrespective of their <it>emm </it>types. However, the presence of superantigen genes in <it>emm </it>and <it>emmL </it>nontypeable strains has not been previously reported. In this study, presence of at least one or a combination of superantigen coding genes was identified in all the <it>emm </it>and <it>emmL </it>nontypeable strains. Thus, the superantigens may inevitably play an important role in the pathogenesis of these nontypeable strains in the absence of the primary virulence factor, M protein.</p

Antimicrobial Peptides: Versatile Biological Properties

Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.</jats:p

Evaluation of INSeq To Identify Genes Essential for

The reciprocal interaction between rhizosphere bacteria and their plant hosts results in a complex battery of genetic and physiological responses. In this study, we used insertion sequencing (INSeq) to reveal the genetic determinants responsible for the fitness of Pseudomonas aeruginosa PGPR2 during root colonization. We generated a random transposon mutant library of Pseudomonas aeruginosa PGPR2 comprising 39,500 unique insertions and identified genes required for growth in culture and on corn roots. A total of 108 genes were identified as contributing to the fitness of strain PGPR2 on roots. The importance in root colonization of four genes identified in the INSeq screen was verified by constructing deletion mutants in the genes and testing them for the ability to colonize corn roots singly or in competition with the wild type. All four mutants were affected in corn root colonization, displaying 5- to 100-fold reductions in populations in single inoculations, and all were outcompeted by the wild type by almost 100-fold after seven days on corn roots in mixed inoculations of the wild type and mutant. The genes identified in the screen had homology to genes involved in amino acid catabolism, stress adaptation, detoxification, signal transduction, and transport. INSeq technology proved a successful tool to identify fitness factors in P aeruginosa PGPR2 for root colonization

Exploring viral diversity in diarrheic porcine feces: a metagenomic analysis from an Indian swine farm

BackgroundPig husbandry is a vital sector in India, providing nutritional security and employment for marginalized communities. Pigs are advantageous due to high reproduction rates and fecundity, shorter generation intervals, and efficient feed conversion, requiring minimal housing. However, the swine industry encounters significant disease challenges, particularly viral gastroenteritis, which poses serious public health risks, especially in developing countries. Pigs serve as natural reservoirs and amplifiers for numerous viruses with zoonotic potential, making disease surveillance essential.MaterialsIn this study, we conducted a metagenomic analysis of 15 fecal samples from diarrheic pigs on a farm in India, marking the first exploration of the fecal virome diversity in this region. Our next-generation sequencing approach has enabled the unbiased detection of multiple viral agents in the porcine fecal samples, detecting both known and novel viral agents without prior target knowledge.ResultsThe key and novel viruses obtained in our study were porcine circovirus, porcine parvovirus 7, porcine mamastrovirus 3, porcine sapelovirus A, and porcine enterovirus G. This work resulted in the generation of full genomes for multiple porcine viruses, including Circovirus, Enterovirus, Sapelovirus, and Mamastrovirus, along with partial genomes of Parvovirus, Picobirnavirus, Porcine stool-associated RNA virus (Porcine Posavirus), Kobuvirus, and Rotavirus, all subjected to phylogenetic analysis.ConclusionOur survey indicates frequent co-infections with diverse viruses, creating conducive environments for viral recombination and reassortment. Continuous surveillance of viral pathogens in animal populations is essential for understanding the dynamics of both known and novel viruses and for detecting emerging pathogens, along with their zoonotic and pathogenic potential

A simple method for selective removal of human DNA from oral microbiome for functional metagenomic applications

572-576This study presents a simple filtration based technique to reduce human DNA contamination in mouthwash samples. Quantitative PCR evaluated efficiency of proposed method in removal of human DNA and selective extraction of bacterial DNA. The b-globin and 16S rDNA were targeted to measure the level of human and bacterial DNA respectively. When compared to unfiltered metagenomic DNA, there was 89% reduction in human DNA along with proportionate enrichment of bacterial DNA was obtained in filtered DNA. This strategy can serve as an efficient method for removal of human DNA and enrichment of microbial DNA in mouth wash samples usefull for functional metagenomic applications. </span