scholarly journals Streptococcus pneumoniae, S. pyogenes and S. agalactiae membrane phospholipid remodelling in response to human serum

Microbiology ◽  
2021 ◽  
Vol 167 (5) ◽  
Author(s):  
Luke R. Joyce ◽  
Ziqiang Guan ◽  
Kelli L. Palmer
Keyword(s):  
Streptococcus Pneumoniae ◽  
Human Serum ◽  
Type Species ◽  
Cellular Membrane ◽  
Defined Medium ◽  
Content Type ◽  
Link Type ◽  
Streptococcal Species ◽  
Group A ◽  
Group B

Streptococcus pneumoniae , S. pyogenes (Group A Streptococcus ; GAS) and S. agalactiae (Group B Streptococcus ; GBS) are major aetiological agents of diseases in humans. The cellular membrane, a crucial site in host–pathogen interactions, is poorly characterized in streptococci. Moreover, little is known about whether or how environmental conditions influence their lipid compositions. Using normal phase liquid chromatography coupled with electrospray ionization MS, we characterized the phospholipids and glycolipids of S. pneumoniae , GAS and GBS in routine undefined laboratory medium, streptococcal defined medium and, in order to mimic the host environment, defined medium supplemented with human serum. In human serum-supplemented medium, all three streptococcal species synthesize phosphatidylcholine (PC), a zwitterionic phospholipid commonly found in eukaryotes but relatively rare in bacteria. We previously reported that S. pneumoniae utilizes the glycerophosphocholine (GPC) biosynthetic pathway to synthesize PC. Through substrate tracing experiments, we confirm that GAS and GBS scavenge lysoPC, a major metabolite in human serum, thereby using an abbreviated GPC pathway for PC biosynthesis. Furthermore, we found that plasmanyl-PC is uniquely present in the GBS membrane during growth with human serum, suggesting GBS possesses unusual membrane biochemical or biophysical properties. In summary, we report cellular lipid remodelling by the major pathogenic streptococci in response to metabolites present in human serum.

scholarly journals Streptococcus pneumoniae, S. pyogenes, and S. agalactiae membrane phospholipid remodeling in response to human serum

2021 ◽  
Author(s):  
Luke. R. Joyce ◽  
Ziqiang Guan ◽  
Kelli L. Palmer
Keyword(s):  
Streptococcus Pneumoniae ◽  
Human Serum ◽  
Cellular Membrane ◽  
Defined Medium ◽  
Ionization Mass ◽  
Streptococcal Species ◽  
Group A ◽  
Phase Liquid ◽  
Etiological Agents ◽  
Group B

AbstractStreptococcus pneumoniae, S. pyogenes (Group A Streptococcus; GAS), and S. agalactiae (Group B Streptococcus; GBS) are major etiological agents of diseases in humans. The cellular membrane, a crucial site in host-pathogen interactions, is poorly characterized in streptococci. Moreover, little is known about whether or how environmental conditions influence their lipid compositions. Using normal phase liquid chromatography coupled with electrospray ionization mass spectrometry, we characterized the phospholipids and glycolipids of S. pneumoniae, GAS, and GBS in routine undefined laboratory medium, streptococcal defined medium, and, in order to mimic the host environment, defined medium supplemented with human serum. In human serum-supplemented medium, all three streptococcal species synthesize phosphatidylcholine (PC), a zwitterionic phospholipid commonly found in eukaryotes but relatively rare in bacteria. We previously reported that S. pneumoniae utilizes the glycerophosphocholine (GPC) biosynthetic pathway to synthesize PC. Through substrate tracing experiments, we confirm that GAS and GBS scavenge lysoPC, a major metabolite in human serum, thereby using an abbreviated GPC pathway for PC biosynthesis. Furthermore, we found that plasmanyl-PC is uniquely present in the GBS membrane during growth with human serum, suggesting GBS possesses unusual membrane biochemical or biophysical properties. In summary, we report cellular lipid remodeling by the major pathogenic streptococci in response to metabolites present in human serum.

scholarly journals Interspecies Communication among Commensal and Pathogenic Streptococci

mBio ◽  
2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Laura C. Cook ◽  
Breah LaSarre ◽  
Michael J. Federle
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Human Pathogens ◽  
Streptococcus Dysgalactiae ◽  
Interspecies Communication ◽  
Content Type ◽  
Streptococcal Species ◽  
Group A ◽  
Group B ◽  
Regulated Gene Expression

ABSTRACTQuorum sensing (QS) regulates diverse and coordinated behaviors in bacteria, including the production of virulence factors, biofilm formation, sporulation, and competence development. It is now established that some streptococci utilize Rgg-type proteins in concert with short hydrophobic peptides (SHPs) to mediate QS, and sequence analysis reveals that several streptococcal species contain highly homologous Rgg/SHP pairs. In group A streptococcus (GAS), two SHPs (SHP2 and SHP3 [SHP2/3]) were previously identified to be important in GAS biofilm formation. SHP2/3 are detected by two antagonistic regulators, Rgg2 and Rgg3, which control expression of theshpgenes. In group B streptococcus (GBS), RovS is a known virulence gene regulator and ortholog of Rgg2, whereas no apparent Rgg3 homolog exists. Adjacent torovSis a gene (shp1520) encoding a peptide nearly identical to SHP2. Using isogenic mutant strains and transcriptional reporters, we confirmed that RovS/SHP1520 comprise a QS circuit in GBS. More important, we performed experiments demonstrating that production and secretion of SHP1520 by GBS can modulate Rgg2/3-regulated gene expression in GAS intrans; likewise, SHP2/3 production by GAS can stimulate RovS-mediated gene regulation in GBS. An isolate ofStreptococcus dysgalactiaesubsp.equisimilisalso produced a secreted factor capable of simulating the QS circuits of both GAS and GBS, and sequencing confirms the presence of an orthologous Rgg2/SHP2 pair in this species as well. To our knowledge, this is the first documented case of bidirectional signaling between streptococcal species in coculture and suggests a role for orthologous Rgg/SHP systems in interspecies communication between important human pathogens.IMPORTANCEPathogenic streptococci, such as group A (GAS) and group B (GBS) streptococcus, are able to persist in the human body without causing disease but become pathogenic under certain conditions that are not fully characterized. Environmental cues and interspecies signaling between members of the human flora likely play an important role in the transition to a disease state. Since quorum-sensing (QS) peptides have been consistently shown to regulate virulence factor production in pathogenic species, the ability of bacteria to signal via these peptides may prove to be an important link between the carrier and pathogenic states. Here we provide evidence of a bidirectional QS system between GAS, GBS, andStreptococcus dysgalactiaesubsp.equisimilis, demonstrating the possibility of evolved communication systems between human pathogens.

scholarly journals Azithromycin resistance mutations in Streptococcus pneumoniae as revealed by a chemogenomic screen

2020 ◽  
Vol 6 (11) ◽  
Author(s):  
Hélène Gingras ◽  
Kévin Patron ◽  
Philippe Leprohon ◽  
Marc Ouellette
Keyword(s):  
Streptococcus Pneumoniae ◽  
Ribosomal Proteins ◽  
Type Species ◽  
Chemical Mutagenesis ◽  
Resistance Mutations ◽  
Content Type ◽  
Link Type ◽  
Chromosomal Changes ◽  
23S Ribosomal Rna ◽  
Ribosomal Binding Site

We report on the combination of chemical mutagenesis, azithromycin selection and next-generation sequencing (Mut-Seq) for the identification of small nucleotide variants that decrease the susceptibility of Streptococcus pneumoniae to the macrolide antibiotic azithromycin. Mutations in the 23S ribosomal RNA or in ribosomal proteins can confer resistance to macrolides and these were detected by Mut-Seq. By concentrating on recurrent variants, we could associate mutations in genes implicated in the metabolism of glutamine with decreased azithromycin susceptibility among S. pneumoniae mutants. Glutamine synthetase catalyses the transformation of glutamate and ammonium into glutamine and its chemical inhibition is shown to sensitize S. pneumoniae to antibiotics. A mutation affecting the ribosomal-binding site of a putative ribonuclease J2 is also shown to confer low-level resistance. Mut-Seq has the potential to reveal chromosomal changes enabling high resistance as well as novel events conferring more subtle phenotypes.

Streptococcus dentisani sp. nov., a novel member of the mitis group

2014 ◽  
Vol 64 (Pt_1) ◽  
pp. 60-65 ◽  
Author(s):  
Anny Camelo-Castillo ◽  
Alfonso Benítez-Páez ◽  
Pedro Belda-Ferre ◽  
Raúl Cabrera-Rubio ◽  
Alex Mira
Keyword(s):  
Type Species ◽  
Spherical Shape ◽  
Culture Collection ◽  
23S Rrna ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
23S Rrna Gene ◽  
Tooth Surfaces ◽  
Streptococcal Species

Genomic, taxonomic and biochemical studies were performed on two strains of α-haemolytic streptococci that showed them to be clustered with major members of the Streptococcus mitis group. These Gram-stain-positive strains were isolated from tooth surfaces of caries-free humans and showed the classical spherical shape of streptococcal species growing in chains. Sequence analysis from concatenated 16S and 23S rRNA gene and sodA genes showed that these strains belonged to the mitis group, but both of them clustered into a new phylogenetic branch. The genomes of these two isolates were sequenced, and whole-genome average nucleotide identity (ANI) demonstrated that these strains significantly differed from any streptococcal species, showing ANI values under 91 % even when compared with the phylogenetically closest species such as Streptococcus oralis and S. mitis . Biochemically, the two isolates also showed distinct metabolic features relative to closely related species, like α-galactosidase activity. From the results of the present study, the name Streptococcus dentisani sp. nov. is proposed to accommodate these novel strains, which have been deposited in open collections at the Spanish type Culture Collection (CECT) and Leibniz Institute DSMZ–German Collection of Microorganisms and Cell Cultures (DSMZ), being respectively identified as Streptococcus dentisani Str. 7746 ( = CECT 8313 = DSM 27089) and Streptococcus dentisani Str. 7747T ( = CECT 8312T = DSM 27088T).

scholarly journals R-type bacteriocins of Xenorhabdus bovienii determine the outcome of interspecies competition in a natural host environment

Microbiology ◽  
2020 ◽  
Vol 166 (11) ◽  
pp. 1074-1087
Author(s):  
Kishore Reddy Venkata Thappeta ◽  
Kristin Ciezki ◽  
Nydia Morales-Soto ◽  
Shane Wesener ◽  
Heidi Goodrich-Blair ◽  
...  
Keyword(s):  
Type Species ◽  
Defined Medium ◽  
Antibiotic Activity ◽  
Natural Host ◽  
Interspecies Competition ◽  
Content Type ◽  
Host Environment ◽  
Link Type ◽  
Specific Species ◽  
High Level

Xenorhabdus species are bacterial symbionts of Steinernema nematodes and pathogens of susceptible insects. Different species of Steinernema nematodes carrying specific species of Xenorhabdus can invade the same insect, thereby setting up competition for nutrients within the insect environment. While Xenorhabdus species produce both diverse antibiotic compounds and prophage-derived R-type bacteriocins (xenorhabdicins), the functions of these molecules during competition in a host are not well understood. Xenorhabdus bovienii (Xb-Sj), the symbiont of Steinernema jollieti, possesses a remnant P2-like phage tail cluster, xbp1, that encodes genes for xenorhabdicin production. We show that inactivation of either tail sheath (xbpS1) or tail fibre (xbpH1) genes eliminated xenorhabdicin production. Preparations of Xb-Sj xenorhabdicin displayed a narrow spectrum of activity towards other Xenorhabdus and Photorhabdus species. One species, Xenorhabdus szentirmaii (Xsz-Sr), was highly sensitive to Xb-Sj xenorhabdicin but did not produce xenorhabdicin that was active against Xb-Sj. Instead, Xsz-Sr produced high-level antibiotic activity against Xb-Sj when grown in complex medium and lower levels when grown in defined medium (Grace’s medium). Conversely, Xb-Sj did not produce detectable levels of antibiotic activity against Xsz-Sr. To study the relative contributions of Xb-Sj xenorhabdicin and Xsz-Sr antibiotics in interspecies competition in which the respective Xenorhabdus species produce antagonistic activities against each other, we co-inoculated cultures with both Xenorhabdus species. In both types of media Xsz-Sr outcompeted Xb-Sj, suggesting that antibiotics produced by Xsz-Sr determined the outcome of the competition. In contrast, Xb-Sj outcompeted Xsz-Sr in competitions performed by co-injection in the insect Manduca sexta, while in competition with the xenorhabdicin-deficient strain (Xb-Sj:S1), Xsz-Sr was dominant. Thus, xenorhabdicin was required for Xb-Sj to outcompete Xsz-Sr in a natural host environment. These results highlight the importance of studying the role of antagonistic compounds under natural biological conditions.

scholarly journals Streptococcus oriloxodontae sp. nov., isolated from the oral cavities of elephants

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3755-3759 ◽  
Author(s):  
Noriko Shinozaki-Kuwahara ◽  
Masanori Saito ◽  
Masatomo Hirasawa ◽  
Kazuko Takada
Keyword(s):  
Sequence Analysis ◽  
Type Species ◽  
Gene Sequence ◽  
Sequence Similarity ◽  
Housekeeping Genes ◽  
Rrna Gene ◽  
Biochemical Tests ◽  
Content Type ◽  
Link Type ◽  
Streptococcal Species

Two strains were isolated from oral cavity samples of healthy elephants. The isolates were Gram-positive, catalase-negative, coccus-shaped organisms that were tentatively identified as a streptococcal species based on the results of biochemical tests. Comparative 16S rRNA gene sequence analysis suggested classification of these organisms in the genus Streptococcus with Streptococcus criceti ATCC 19642T and Streptococcus orisuis NUM 1001T as their closest phylogenetic neighbours with 98.2 and 96.9 % gene sequence similarity, respectively. When multi-locus sequence analysis using four housekeeping genes, groEL, rpoB, gyrB and sodA, was carried out, similarity of concatenated sequences of the four housekeeping genes from the new isolates and Streptococcus mutans was 89.7 %. DNA–DNA hybridization experiments suggested that the new isolates were distinct from S. criceti and other species of the genus Streptococcus . On the basis of genotypic and phenotypic differences, it is proposed that the novel isolates are classified in the genus Streptococcus as representatives of Streptococcus oriloxodontae sp. nov. The type strain of S. oriloxodontae is NUM 2101T ( = JCM 19285T = DSM 27377T).

scholarly journals Co-infection in critically ill patients with COVID-19: an observational cohort study from England

2021 ◽  
Vol 70 (4) ◽  
Author(s):  
Vadsala Baskaran ◽  
Hannah Lawrence ◽  
Louise E. Lansbury ◽  
Karmel Webb ◽  
Shahideh Safavi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cohort Study ◽  
Streptococcus Pneumoniae ◽  
Critically Ill ◽  
Type Species ◽  
Severe Illness ◽  
Gram Negative ◽  
Content Type ◽  
Link Type ◽  
Icu Stay

Introduction. During previous viral pandemics, reported co-infection rates and implicated pathogens have varied. In the 1918 influenza pandemic, a large proportion of severe illness and death was complicated by bacterial co-infection, predominantly Streptococcus pneumoniae and Staphylococcus aureus . Gap statement. A better understanding of the incidence of co-infection in patients with COVID-19 infection and the pathogens involved is necessary for effective antimicrobial stewardship. Aim. To describe the incidence and nature of co-infection in critically ill adults with COVID-19 infection in England. Methodology. A retrospective cohort study of adults with COVID-19 admitted to seven intensive care units (ICUs) in England up to 18 May 2020, was performed. Patients with completed ICU stays were included. The proportion and type of organisms were determined at <48 and >48 h following hospital admission, corresponding to community and hospital-acquired co-infections. Results. Of 254 patients studied (median age 59 years (IQR 49–69); 64.6 % male), 139 clinically significant organisms were identified from 83 (32.7 %) patients. Bacterial co-infections/ co-colonisation were identified within 48 h of admission in 14 (5.5 %) patients; the commonest pathogens were Staphylococcus aureus (four patients) and Streptococcus pneumoniae (two patients). The proportion of pathogens detected increased with duration of ICU stay, consisting largely of Gram-negative bacteria, particularly Klebsiella pneumoniae and Escherichia coli . The co-infection/ co-colonisation rate >48 h after admission was 27/1000 person-days (95 % CI 21.3–34.1). Patients with co-infections/ co-colonisation were more likely to die in ICU (crude OR 1.78,95 % CI 1.03–3.08, P=0.04) compared to those without co-infections/ co-colonisation. Conclusion. We found limited evidence for community-acquired bacterial co-infection in hospitalised adults with COVID-19, but a high rate of Gram-negative infection acquired during ICU stay.

scholarly journals The prevalence of pilus islets in Streptococcus pneumoniae isolates from healthy children in Indonesia

2020 ◽  
Author(s):  
Dodi Safari ◽  
Feby Valentiya ◽  
Korrie Salsabila ◽  
Wisiva Tofriska Paramaiswari ◽  
Wisnu Tafroji ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Type Species ◽  
Pneumococcal Vaccination ◽  
Healthy Children ◽  
Upper Respiratory Tract ◽  
Content Type ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Link Type ◽  
Islet 1

Streptococcus pneumoniae produces pili that function as adherence factors to bind to epithelial cells in the human upper respiratory tract. In this study, we investigated the prevalence of pilus islets (PIs) in S. pneumoniae strains carried by healthy children below 5 years of age prior to pneumococcal vaccination in 2012 in Lombok Island, Indonesia. In all, 347 archived S. pneumoniae isolates were screened using polymerase chain reactions for the presence of rrgC and pitB genes representing pilus islet 1 (PI-1) and pilus islet 2 (PI-2), respectively. We found that 40 isolates (11.5 %) contained the PI genes: 5.2% carried both PI-1 and PI-2, and 3.5 and 2.9% carried PI-1 and PI-2, respectively. Furthermore, we found that most of the strains carrying either of the PIs belonged to the vaccine serotypes 19F and 19A and were less susceptible to chloramphenicol and tetracycline.

scholarly journals Population genetic structure, serotype distribution and antibiotic resistance of Streptococcus pneumoniae causing invasive disease in children in Argentina

2021 ◽  
Vol 7 (9) ◽  
Author(s):  
Paula Gagetti ◽  
Stephanie W. Lo ◽  
Paulina A. Hawkins ◽  
Rebecca A. Gladstone ◽  
Mabel Regueira ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Resistance ◽  
Type Species ◽  
Invasive Disease ◽  
Multidrug Resistant ◽  
Childhood Immunization ◽  
Content Type ◽  
Sequencing Project ◽  
Link Type ◽  
Immunization Programme

Invasive disease caused by Streptococcus pneumoniae (IPD) is one of the leading causes of morbidity and mortality in young children worldwide. In Argentina, PCV13 was introduced into the childhood immunization programme nationwide in 2012 and PCV7 was available from 2000, but only in the private market. Since 1993 the National IPD Surveillance Programme, consisting of 150 hospitals, has conducted nationwide pneumococcal surveillance in Argentina in children under 6 years of age, as part of the SIREVA II-OPS network. A total of 1713 pneumococcal isolates characterized by serotype (Quellung) and antimicrobial resistance (agar dilution) to ten antibiotics, belonging to three study periods: pre-PCV7 era 1998–1999 (pre-PCV), before the introduction of PCV13 2010–2011 (PCV7) and after the introduction of PCV13 2012–2013 (PCV13), were available for inclusion. Fifty-four serotypes were identified in the entire collection and serotypes 14, 5 and 1 represented 50 % of the isolates. Resistance to penicillin was 34.9 %, cefotaxime 10.6 %, meropenem 4.9 %, cotrimoxazole 45 %, erythromycin 21.5 %, tetracycline 15.4 % and chloramphenicol 0.4 %. All the isolates were susceptible to levofloxacin, rifampin and vancomycin. Of 1713 isolates, 1061 (61.9 %) were non-susceptible to at least one antibiotic and 235(13.7 %) were multidrug resistant. A subset of 413 isolates was randomly selected and whole-genome sequenced as part of Global Pneumococcal Sequencing Project (GPS). The genome data was used to investigate the population structure of S. pneumoniae defining pneumococcal lineages using Global Pneumococcal Sequence Clusters (GPSCs), sequence types (STs) and clonal complexes (CCs), prevalent serotypes and their associated pneumococcal lineages and genomic inference of antimicrobial resistance. The collection showed a great diversity of strains. Among the 413 isolates, 73 known and 36 new STs were identified belonging to 38 CCs and 25 singletons, grouped into 52 GPSCs. Important changes were observed among vaccine types when pre-PCV and PCV13 periods were compared; a significant decrease in serotypes 14, 6B and 19F and a significant increase in 7F and 3. Among non-PCV13 types, serogroup 24 increased from 0 % in pre-PCV to 3.2 % in the PCV13 period. Our analysis showed that 66.1 % (273/413) of the isolates were predicted to be non-susceptible to at least one antibiotic and 11.9 % (49/413) were multidrug resistant. We found an agreement of 100 % when comparing the serotype determined by Quellung and WGS-based serotyping and 98.4 % of agreement in antimicrobial resistance. Continued surveillance of the pneumococcal population is needed to reveal the dynamics of pneumococcal isolates in Argentina in post-PCV13. This article contains data hosted by Microreact.

Pathogenicity and drug resistance of animal streptococci responsible for human infections

2021 ◽  
Vol 70 (3) ◽  
Author(s):  
Paulina Glajzner ◽  
Eligia Maria Szewczyk ◽  
Magdalena Szemraj
Keyword(s):  
Antibiotic Resistance ◽  
Type Species ◽  
Streptococcus Bovis ◽  
Content Type ◽  
Streptococcus Species ◽  
Link Type ◽  
Animal Pathogens ◽  
Streptococcal Species ◽  
New Hosts ◽  
Human Infections

Bacteria of the genus Streptococcus , earlier considered typically animal, currently have also been causing infections in humans. It is necessary to make clinicians aware of the emergence of new species that may cause the development of human diseases. There is an increasing frequency of isolation of streptococci such as S. suis , S. dysgalactiae , S. iniae and S. equi from people. Isolation of Streptococcus bovis/Streptococcus equinus complex bacteria has also been reported. The streptococcal species described in this review are gaining new properties and virulence factors by which they can thrive in new environments. It shows the potential of these bacteria to changes in the genome and the settlement of new hosts. Information is presented on clinical cases that concern streptococcus species belonging to the groups Bovis, Pyogenic and Suis. We also present the antibiotic resistance profiles of these bacteria. The emerging resistance to β-lactams has been reported. In this review, the classification, clinical characteristics and antibiotic resistance of groups and species of streptococci considered as animal pathogens are summarized.

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