Streptococcus pyogenes (the Group A Streptococcus, GAS) is a Gram-positive bacterium responsible for a wide spectrum of diseases ranging from mild superficial infections (pharyngitis, impetigo) to severe, often life-threatening invasive diseases (necrotizing fasciitis, streptococcal toxic shock syndrome) in humans. This unit describes molecular techniques for the genetic manipulation of S. pyogenes with detailed protocols for transformation, gene disruption, allelic exchange, transposon mutagenesis, and genetic complementation. PMID:24510894
Le Breton, Yoann; McIver, Kevin S
Over the past 25 years, the clinical course of Kawasaki disease has been defined, the prevalence and nature of the cardiovascular effects widely understood, and pathological changes in the most severe cases well described. However, the aetiology and pathogenesis of this puzzling disease have remained unclear, thus specific therapy is not yet available. Because of some close clinical similarities between
T. Akiyama; K. Yashiro
Streptococcus pyogenes (Group A Streptococcus or GAS) is a Gram-positive bacterial pathogen that has shown complex modes of regulation of its virulence factors to cause diverse diseases. Bacterial small RNAs are regarded as novel widespread regulators of gene expression in response to environmental signals. Recent studies have revealed that several small RNAs (sRNAs) have an important role in S. pyogenes physiology and pathogenesis by regulating gene expression at the translational level. To search for new sRNAs in S. pyogenes, we performed a genomewide analysis through computational prediction followed by experimental verification. To overcome the limitation of low accuracy in computational prediction, we employed a combination of three different computational algorithms (sRNAPredict, eQRNA and RNAz). A total of 45 candidates were chosen based on the computational analysis, and their transcription was analyzed by reverse-transcriptase PCR and Northern blot. Through this process, we discovered 7 putative novel trans-acting sRNAs. Their abundance varied between different growth phases, suggesting that their expression is influenced by environmental or internal signals. Further, to screen target mRNAs of an sRNA, we employed differential RNA sequencing analysis. This study provides a significant resource for future study of small RNAs and their roles in physiology and pathogenesis of S. pyogenes. PMID:23762235
Tesorero, Rafael A; Yu, Ning; Wright, Jordan O; Svencionis, Juan P; Cheng, Qiang; Kim, Jeong-Ho; Cho, Kyu Hong
Streptococcus pyogenes is an uncommon cause of community-acquired pneumonia and there have been few recent specific accounts of the condition. To\\u000a describe the current nature of this disease in the UK, data was gathered on patients with clinical pneumonia from whom Streptococcus pyogenes was cultured principally from blood or other relevant normally sterile sites. In the Harrogate and Northallerton districts
M. Barnham; N. C. Weightman; A. W. Anderson; F. S. Pagan; S. T. Chapman
Background CovRS (or CsrRS) is a two-component regulatory system that regulates the production of multiple virulence factors in Streptococcus pyogenes. covS mutations are often found in isolates recovered from mice that have been experimentally infected with S. pyogenes and covS mutations enhance bacterial virulence in an invasive infection mouse model. In addition, covS mutations were detected more frequently in a panel of clinical isolates from severe invasive streptococcal infections than those from non-severe infections. Thus, covS mutations may be associated with the onset of severe invasive infections. Results Known covS mutations were divided into two groups: (i) frameshift mutations that caused a deletion of functional regions and (ii) point mutations that caused single (or double) amino acid(s) substitutions. Frameshift mutations are frequent in mouse-passaged isolates, whereas point mutations are frequent in clinical isolates. The functions of CovS proteins with a single amino acid substitution in clinical isolates were estimated based on the streptococcal pyrogenic exotoxin B (SpeB) production and NAD+-glycohydrolase (NADase) activity, which are known to be regulated by the CovRS system. Point mutations partially, but not completely, impaired the function of the covS alleles. We also investigated some of the benefits that a partial loss of function in covS alleles with point mutations might confer on clinical isolates. We found that covS knockout mutants (?covS strains) had an impaired growth ability in a normal atmosphere in Todd Hewitt broth compared with parental isolates having wild-type or point-mutated covS. Conclusions The loss of CovS proteins in S. pyogenes may confer greater virulence, but bacteria may also lose the ability to respond to certain external signals recognized by CovS. Therefore, point mutations that retain the function of CovS and confer hypervirulence may have natural selective advantages.
Streptococcus pyogenes (group A streptococcus) is a gram- positive pathogenic bacterium that causes pharyngitis, impe- tigo, scarlet fever, and streptococcal toxic shock-like syndrome (TSLS) (23). These diseases are initiated by the adhesion of S. pyogenes to epithelial cells in the upper respiratory tract or skin. In the process of adhesion, extracellular matrix proteins such as fibronectin (Fn) and laminin (Lm)
Yutaka Terao; Shigetada Kawabata; Eiji Kunitomo; Ichiro Nakagawa; Shigeyuki Hamada
In Belgium, decreasing macrolide, lincosamide, streptogramins B, and tetracycline use during 1997–2007 correlated significantly with decreasing macrolide-resistant Streptococcus pyogenes during 1999–2009. Maintaining drug use below a critical threshold corresponded with low-level macrolide-resistant S. pyogenes and an increased number of erm(A)-harboring emm77 S. pyogenes with low fitness costs.
Van Heirstraeten, Liesbet; Coenen, Samuel; Lammens, Christine; Hens, Niel; Goossens, Herman
Streptococcus pyogenes, is an important human pathogen classified within the pyogenic group of streptococci, exclusively adapted to the human host. Our goal was to employ a comparative evolutionary approach to better understand the genomic events concomitant with S. pyogenes human adaptation. As part of ascertaining these events, we sequenced the genome of one of the potential sister species, the agricultural pathogen S. canis, and combined it in a comparative genomics reconciliation analysis with two other closely related species, Streptococcus dysgalactiae and Streptococcus equi, to determine the genes that were gained and lost during S. pyogenes evolution. Genome wide phylogenetic analyses involving 15 Streptococcus species provided convincing support for a clade of S. equi, S. pyogenes, S. dysgalactiae, and S. canis and suggested that the most likely S. pyogenes sister species was S. dysgalactiae. The reconciliation analysis identified 113 genes that were gained on the lineage leading to S. pyogenes. Almost half (46%) of these gained genes were phage associated and 14 showed significant matches to experimentally verified bacteria virulence factors. Subsequent to the origin of S. pyogenes, over half of the phage associated genes were involved in 90 different LGT events, mostly involving different strains of S. pyogenes, but with a high proportion involving the horse specific pathogen S. equi subsp. equi, with the directionality almost exclusively (86%) in the S. pyogenes to S. equi direction. Streptococcus agalactiae appears to have played an important role in the evolution of S. pyogenes with a high proportion of LGTs originating from this species. Overall the analysis suggests that S. pyogenes adaptation to the human host was achieved in part by (i) the integration of new virulence factors (e.g. speB, and the sal locus) and (ii) the construction of new regulation networks (e.g. rgg, and to some extent speB).
Lefebure, Tristan; Richards, Vince P.; Lang, Ping; Pavinski-Bitar, Paulina; Stanhope, Michael J.
The capsule of Streptococcus pyogenes serves as an adhesin as well as an anti-phagocytic factor by binding to CD44 on keratinocytes of the pharyngeal mucosa and the skin, the main entry sites of the pathogen. We discovered that S. pyogenes HSC5 and MGAS315 strains are further thermoregulated for capsule production at a post-transcriptional level in addition to the transcriptional regulation by the CovRS two-component regulatory system. When the transcription of the hasABC capsular biosynthetic locus was de-repressed through mutation of the covRS system, the two strains, which have been used for pathogenesis studies in the laboratory, exhibited markedly increased capsule production at sub-body temperature. Employing transposon mutagenesis, we found that CvfA, a previously identified membrane-associated endoribonuclease, is required for the thermoregulation of capsule synthesis. The mutation of the cvfA gene conferred increased capsule production regardless of temperature. However, the amount of the capsule transcript was not changed by the mutation, indicating that a post-transcriptional regulator mediates between CvfA and thermoregulated capsule production. When we tested naturally occurring invasive mucoid strains, a high percentage (11/53, 21%) of the strains exhibited thermoregulated capsule production. As expected, the mucoid phenotype of these strains at sub-body temperature was due to mutations within the chromosomal covRS genes. Capsule thermoregulation that exhibits high capsule production at lower temperatures that occur on the skin or mucosal surface potentially confers better capability of adhesion and invasion when S. pyogenes penetrates the epithelial surface.
Kang, Song Ok; Wright, Jordan O.; Tesorero, Rafael A.; Lee, Hyunwoo; Beall, Bernard; Cho, Kyu Hong
Summary Three novel streptococcal superantigen genes ( spe-g , spe-h , and spe-j ) were identified from the Streptococcus pyogenes M1 genomic database at the University of Oklahoma. A fourth novel gene ( smez-2 ) was isolated from the S. pyogenes strain 2035, based on sequence homology to the streptococcal mitogenic exotoxin z ( smez ) gene. SMEZ-2, SPE-G, and
Thomas Proft; S. Louise Moffatt; Celia J. Berkahn; John D. Fraser
Infections caused by group A streptococcus (GAS) represent a public health problem in both developing and developed countries. The current available methods of prevention are either inadequate or ineffective, which is highlighted by the resurgence in invasive GAS infections over the past two decades. The management of GAS and associated diseases requires new and improved approaches. This review discusses various
Manisha Pandey; Silvana Sekuloski; Michael R Batzloff; Batzloff
We have re-examined the stringent response of Streptococcus rattus and Streptococcus pyogenes, two organisms that had originally been reported not to accumulate ppGpp following amino acid deprivation. We conclude that ppGpp does accumulate when S. rattus and S. pyogenes are deprived of isoleucine by mupirocin addition. The kinetics of ppGpp accumulation was faster in S. pyogenes compared with S. rattus.
Kathryn E Whitehead; Gillian M Webber; Reg R England
Streptococcus pyogenes is an important cause of human morbidity and mortality worldwide. A wealth of genomic information related to this pathogen has facilitated exploration of the proteome, particularly in response to environmental conditions thought to mimic various aspects of pathogenesis. Proteomic approaches are also used to identify immunoreactive proteins for vaccine development and to identify proteins that may induce autoimmunity. These studies have revealed new mechanisms involved in regulating the S. pyogenes proteome, which has opened up new avenues in the study of S. pyogenes pathogenesis. This article describes the methods used, and progress being made towards characterizing the S. pyogenes proteome, including studies seeking to identify potential vaccine candidates.
Dmitriev, Alexander V; Chaussee, Michael S
Chromosomal diversity and relationships among 126 Streptococcus pyogenes strains expressing M1 protein from 13 countries on five continents were analyzed by multilocus enzyme electrophoresis and restriction fragment profiling by pulsed-field gel electrophoresis. All isolates were studied for the presence of the gene encoding streptococcal pyrogenic exotoxin A by PCR. Strain subsets were also examined by automated DNA sequencing for allelic polymorphism in genes encoding M protein (emm), streptococcal pyrogenic exotoxin A (speA), streptokinase (ska), pyrogenic exotoxin B (interleukin-1 beta convertase) (speB), and C5a peptidase (scp). Seven distinct emm1 alleles that encode M proteins differing at one or more amino acids in the N-terminal variable region were identified. Although substantial levels of genetic diversity exist among M1-expressing organisms, most invasive disease episodes are caused by two subclones marked by distinctive multilocus enzyme electrophoretic profiles and pulsed-field gel electrophoresis restriction fragment length polymorphism (RFLP) types. One of these subclones (ET 1/RFLP pattern 1a) has the speA gene and was recovered worldwide. Identity of speA, emm1, speB, and ska alleles in virtually all isolates of ET 1/RFLP type 1a means that these organisms share a common ancestor and that global dispersion of this M1-expressing subclone has occurred very recently. The occurrence of the same emm and ska alleles in strains that are well differentiated in overall chromosomal character demonstrates that horizontal transfer and recombination play a fundamental role in diversifying natural populations of S. pyogenes.
Musser, J M; Kapur, V; Szeto, J; Pan, X; Swanson, D S; Martin, D R
Fifty-seven strains ofStreptococcus pyogenes isolated from septic patients and 52 isolates from nonbacteremic patients in southern israel were investigated for their susceptibility to new macrolides and other antimicrobial drugs. In addition, typing of the isolates by M protein and T antigen was performed. All organisms were susceptible to penicillin and chloramphenicol, 59% to tetracycline, and 7% to trimethoprim-sulfamethoxazole. All isolates
I. Weiss; Z. Gorodnitzky; Z. Korenman; P. Yagupsky
Streptococcus pyogenes (or group A beta hemolytic streptococcus) is a pathogenic bacterium that can give rise to a range of invasive and autoimmune diseases, although it is more widely known as the cause of tonsillitis. It is particularly interesting to note that this germ only causes disease in humans. For many years it has been acknowledged that it can cause an autoimmune brain disease (Sydenham s chorea). Yet, the spectrum of post streptococcal brain disorders has recently been extended to include other movement disorders such as tics or dystonia. A number of systematic psychiatric studies have shown that certain emotional disorders generally accompany the movement disorder (particularly, obsessive compulsive disorder). The proposed pathogenetic mechanism is that of a neuronal dysfunction in which antibodies play a mediating role. The antibodies that are produced after the streptococcal infection cross react with neuronal proteins, and more especially so in individuals with a propensity. This represents a possible model of immunological mimicry and its potential importance with respect to certain idiopathic disorders such as Tourette syndrome and obsessive compulsive disorder. PMID:12861520
Dale, R C
Virulent M protein-containing strains of Streptococcus pyogenes were found to adhere well to human pharyngeal cells in vitro. In contrast, an avirulent M - strain and an enteropathogenic Escherichia coli strain adhered feebly. When various rat tissues were exposed to mixtures of a virulent S. pyogenes strain and an enteropathogenic E. coli strain, the relative proportions of the two pathogenic strains recovered from mucosal surfaces differed among the sites studied. S. pyogenes cells were found to adhere in higher proportions than enteropathogenic E. coli cells to the mucosal surfaces of rat tongues, whereas on surfaces of the urinary bladder, their affinities were reversed. The data indicate that bacterial adherence is influenced by the specificity of both the bacterial and epithelial surfaces, and they suggest that adherence may influence the tissue tropisms of pathogens. Early stationary-phase cells of S. pyogenes attached better to epithelial cells than did bacteria in other growth phases. The adherence of S. pyogenes cells was impaired by pretreatment with trypsin, wheat germ lipase, Tween 80, Triton X-100, sodium lauryl sulfate, heat at 56 C, anti-group A antiserum, the presence of phospholipids, and preincubation of the epithelial cells with Streptococcus salivarius cell walls. Altering the pH or treatment with ethylenediaminetetraacetic acid had no effect on the ability of S. pyogenes cells to adhere. PMID:4587386
Ellen, R P; Gibbons, R J
The objective of this study was to determine the characteristics of Streptococcus pyogenes isolated during a 10-month period from members of a family with infections and asymptomatic carriage. T-serotyping and pulsed-field gel electrophoresis confirmed that distinct GAS clones were introduced into the family over a short period of time. PMID:12848734
Mazón, A; Gil-Setas, A; Sota de la Gándara, L J; Vindel, A; Sáez-Nieto, J A
Streptococcus pyogenes is commonly believed to be resistant to trimethoprim-sulfamethoxazole (SXT), resulting in reservations about using SXT for skin and soft tissue infections (SSTI) where S. pyogenes is involved. S. pyogenes' in vitro susceptibility to SXT depends on the medium's thymidine content. Thymidine allows S. pyogenes to bypass the sulfur-mediated inhibition of folate metabolism and, historically, has resulted in apparently reduced susceptibility of S. pyogenes to sulfur antibacterials. The low thymidine concentration in Mueller-Hinton agar (MHA) is now regulated. We explored S. pyogenes susceptibility to SXT on various media. Using two sets of 100 clinical S. pyogenes isolates, we tested for susceptibility using SXT Etests on MHA containing defibrinated horse blood and 20 mg/liter ?-NAD (MHF), MHA with sheep blood (MHS), MHA alone, MHA with horse blood (MHBA), and MHA with lysed horse blood (MHLHBA). European Committee on Antibacterial Susceptibility Testing (EUCAST) breakpoints defined susceptibility (MIC, ? 1 mg/liter) and resistance (MIC, >2 mg/liter). In study 1, 99% of S. pyogenes isolates were susceptible to SXT on MHA, MHBA, and MHLHBA, with geometric mean MICs of 0.04, 0.04, and 0.05 mg/liter, respectively. In study 2, all 100 S. pyogenes isolates were susceptible to SXT on MHF, MHS, MHA, and MHLHBA with geometric mean MICs of 0.07, 0.16, 0.07, and 0.09 mg/liter, respectively. This study confirms the in vitro susceptibility of S. pyogenes to SXT, providing support for the use of SXT for SSTIs. A clinical trial using SXT for impetigo is ongoing. PMID:23052313
Bowen, Asha C; Lilliebridge, Rachael A; Tong, Steven Y C; Baird, Robert W; Ward, Peter; McDonald, Malcolm I; Currie, Bart J; Carapetis, Jonathan R
Streptococcus pyogenes (group A Streptococcus [GAS]) causes a wide variety of diseases, ranging from mild noninvasive to severe invasive infections. Mutations in regulatory components have been implicated in the switch from colonization to invasive phenotypes. The inactivation of the sil locus, composed of six genes encoding a quorum-sensing complex, gives rise to a highly invasive strain. However, studies conducted on limited collections of GAS strains suggested that sil prevalence is around 15%; furthermore, whereas a correlation between the presence of sil and the genetic background was suggested, no link between the presence of a functional sil locus and the invasive status was assessed. We established a collection of 637 nonredundant strains covering all emm genotypes present in France and of known clinical history; 68%, 22%, and 10% were from invasive infections, noninvasive infections, and asymptomatic carriage, respectively. Among the 637 strains, 206 were sil positive. The prevalence of the sil locus varied according to the emm genotype, being present in >85% of the emm4, emm18, emm32, emm60, emm87, and emm90 strains and absent from all emm1, emm28, and emm89 strains. A random selection based on 2009 French epidemiological data indicated that 16% of GAS strains are sil positive. Moreover, due to mutations leading to truncated proteins, only 9% of GAS strains harbor a predicted functional sil system. No correlation was observed between the presence or absence of a functional sil locus and the strain invasiveness status. PMID:24671796
Plainvert, Céline; Dinis, Márcia; Ravins, Miriam; Hanski, Emanuel; Touak, Gérald; Dmytruk, Nicolas; Fouet, Agnès; Poyart, Claire
Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred. PMID:23662123
Sfeir, Julien; Lefrançois, Corinne; Baudoux, Dominique; Derbré, Séverine; Licznar, Patricia
Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred.
Sfeir, Julien; Lefrancois, Corinne; Baudoux, Dominique; Derbre, Severine; Licznar, Patricia
In a nationwide study in Germany covering 13 clinical microbiology laboratories, a total of 307 Streptococcus pyogenes (mainly pharyngitis) and 333 Streptococcus pneumoniae (respiratory tract infections) strains were collected from outpatients less than 16 years of age. The MICs of penicillin G, amoxicillin, cefotaxime, erythromycin A, clindamycin, levofloxacin, and telithromycin were determined by the microdilution method. In S. pyogenes isolates,
Ralf ReneReinert; Rudolf Lutticken; Adnan Al-Lahham
The taxonomic status and structure of Streptococcus dysgalactiae have been the object of much confusion. Bacteria belonging to this species are usually referred to as Lancefield group C or group G streptococci in clinical settings in spite of the fact that these terms lack precision and prevent recognition of the exact clinical relevance of these bacteria. The purpose of this study was to develop an improved basis for delineation and identification of the individual species of the pyogenic group of streptococci in the clinical microbiology laboratory, with a special focus on S. dysgalactiae. We critically reexamined the genetic relationships of the species S. dysgalactiae, Streptococcus pyogenes, Streptococcus canis, and Streptococcus equi, which may share Lancefield group antigens, by phylogenetic reconstruction based on multilocus sequence analysis (MLSA) and 16S rRNA gene sequences and by emm typing combined with phenotypic characterization. Analysis of concatenated sequences of seven genes previously used for examination of viridans streptococci distinguished robust and coherent clusters. S. dysgalactiae consists of two separate clusters consistent with the two recognized subspecies dysgalactiae and equisimilis. Both taxa share alleles with S. pyogenes in several housekeeping genes, which invalidates identification based on single-locus sequencing. S. dysgalactiae, S. canis, and S. pyogenes constitute a closely related branch within the genus Streptococcus indicative of recent descent from a common ancestor, while S. equi is highly divergent from other species of the pyogenic group streptococci. The results provide an improved basis for identification of clinically important pyogenic group streptococci and explain the overlapping spectrum of infections caused by the species associated with humans.
Methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pyogenes (group A streptococcus [GrAS]) cause serious and sometimes fatal human diseases. They are among the many Gram-positive pathogens for which resistance to leading antibiotics has emerged. As a result, alternative therapies need to be developed to combat these pathogens. We have identified a novel bacteriophage lysin (PlySs2), derived from a Streptococcus suis phage, with broad lytic activity against MRSA, vancomycin-intermediate S. aureus (VISA), Streptococcus suis, Listeria, Staphylococcus simulans, Staphylococcus epidermidis, Streptococcus equi, Streptococcus agalactiae (group B streptococcus [GBS]), S. pyogenes, Streptococcus sanguinis, group G streptococci (GGS), group E streptococci (GES), and Streptococcus pneumoniae. PlySs2 has an N-terminal cysteine-histidine aminopeptidase (CHAP) catalytic domain and a C-terminal SH3b binding domain. It is stable at 50 °C for 30 min, 37 °C for >24 h, 4°C for 15 days, and -80 °C for >7 months; it maintained full activity after 10 freeze-thaw cycles. PlySs2 at 128 ?g/ml in vitro reduced MRSA and S. pyogenes growth by 5 logs and 3 logs within 1 h, respectively, and exhibited a MIC of 16 ?g/ml for MRSA. A single, 2-mg dose of PlySs2 protected 92% (22/24) of the mice in a bacteremia model of mixed MRSA and S. pyogenes infection. Serially increasing exposure of MRSA and S. pyogenes to PlySs2 or mupirocin resulted in no observed resistance to PlySs2 and resistance to mupirocin. To date, no other lysin has shown such notable broad lytic activity, stability, and efficacy against multiple, leading, human bacterial pathogens; as such, PlySs2 has all the characteristics to be an effective therapeutic. PMID:23571534
Gilmer, Daniel B; Schmitz, Jonathan E; Euler, Chad W; Fischetti, Vincent A
Methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pyogenes (group A streptococcus [GrAS]) cause serious and sometimes fatal human diseases. They are among the many Gram-positive pathogens for which resistance to leading antibiotics has emerged. As a result, alternative therapies need to be developed to combat these pathogens. We have identified a novel bacteriophage lysin (PlySs2), derived from a Streptococcus suis phage, with broad lytic activity against MRSA, vancomycin-intermediate S. aureus (VISA), Streptococcus suis, Listeria, Staphylococcus simulans, Staphylococcus epidermidis, Streptococcus equi, Streptococcus agalactiae (group B streptococcus [GBS]), S. pyogenes, Streptococcus sanguinis, group G streptococci (GGS), group E streptococci (GES), and Streptococcus pneumoniae. PlySs2 has an N-terminal cysteine-histidine aminopeptidase (CHAP) catalytic domain and a C-terminal SH3b binding domain. It is stable at 50°C for 30 min, 37°C for >24 h, 4°C for 15 days, and ?80°C for >7 months; it maintained full activity after 10 freeze-thaw cycles. PlySs2 at 128 ?g/ml in vitro reduced MRSA and S. pyogenes growth by 5 logs and 3 logs within 1 h, respectively, and exhibited a MIC of 16 ?g/ml for MRSA. A single, 2-mg dose of PlySs2 protected 92% (22/24) of the mice in a bacteremia model of mixed MRSA and S. pyogenes infection. Serially increasing exposure of MRSA and S. pyogenes to PlySs2 or mupirocin resulted in no observed resistance to PlySs2 and resistance to mupirocin. To date, no other lysin has shown such notable broad lytic activity, stability, and efficacy against multiple, leading, human bacterial pathogens; as such, PlySs2 has all the characteristics to be an effective therapeutic.
Gilmer, Daniel B.; Schmitz, Jonathan E.; Euler, Chad W.
The proteins in the culture supernatant (exoproteins) from Streptococcus pyogenes serotype M1 were separated by two-dimensional gel electrophoresis, and their N-terminal amino acid sequences were determined. The amino acid sequences were compared to sequences in the S. pyogenes genome database. The coding sequence showed similarity to sequences of two genes, mf2-v ( mf2 variant) and mf3, which had sequence similarity to genes encoding mitogenic factor (MF); MF has DNase activity. The recombinant genes were expressed in Escherichia coli and the proteins were synthesized. Mf2-v and Mf3 had DNase activity. The activity of Mf2-v was localized to the C-terminal half of the protein. The mf3 gene was shown to be present in most clinically isolated strains of S. pyogenes tested, and the mf2gene was detected in 20% of the isolates. The products of the mf2 and mf3 genes in clinically isolated S. pyogenes strains were thus shown to be DNases. PMID:12029390
Hasegawa, Tadao; Torii, Keizo; Hashikawa, Shinnosuke; Iinuma, Yoshitsugu; Ohta, Michio
Streptococcus pyogenes biofilms tend to exhibit significant tolerance to antimicrobials during infections. We screened coral-associated actinomycetes\\u000a (CAA) for antibiofilm activity against different biofilm forming M serotype of Streptococcus pyogenes. Actinomycetes isolated from the mucus of the coral Acropora digitifera were screened for antibiofilm activity against S. pyogenes biofilms wherein several isolates clearly demonstrated antibiofilm activity. The biofilm inhibitory concentrations (BICs)
Paramasivam Nithyanand; Ramalingam Thenmozhi; Janarthanam Rathna; Shunmugiah Karutha Pandian
Streptococcus pyogenes is a major human bacterial pathogen responsible for severe and invasive disease associated with high mortality rates. The bacterium interacts with several human blood plasma proteins and clarifying these interactions and their biological consequences will help to explain the progression from mild to severe infections. In this study, we used a combination of mass spectrometry (MS) based techniques to comprehensively quantify the components of the S. pyogenes-plasma protein interaction network. From an initial list of 181 interacting human plasma proteins defined using liquid chromatography (LC)-MS/MS analysis we further subdivided the interacting protein list using selected reaction monitoring (SRM) depending on the level of enrichment and protein concentration on the bacterial surface. The combination of MS methods revealed several previously characterized interactions between the S. pyogenes surface and human plasma along with many more, so far uncharacterised, possible plasma protein interactions with S. pyogenes. In follow-up experiments, the combination of MS techniques was applied to study differences in protein binding to a S. pyogenes wild type strain and an isogenic mutant lacking several important virulence factors, and a unique pair of invasive and non-invasive S. pyogenes isolates from the same patient. Comparing the plasma protein-binding properties of the wild type and the mutant and the invasive and non-invasive S. pyogenes bacteria revealed considerable differences, underlining the significance of these protein interactions. The results also demonstrate the power of the developed mass spectrometry method to investigate host-microbial relationships with a large proteomics depth and high quantitative accuracy. PMID:24525632
Sjöholm, Kristoffer; Karlsson, Christofer; Linder, Adam; Malmström, Johan
The Indigenous population of the Northern Territory of Australia (NT) suffers from a very high burden of Streptococcus pyogenes disease, including cardiac and renal sequelae. The aim of this study was to determine if S. pyogenes isolated from this population represent NT endemic strains, or conversely reflect strains with global distribution. emm sequence typing data were used to select 460 S. pyogenes isolates representing NT S. pyogenes diversity from 1987-2008. These isolates were genotyped using either multilocus sequence typing (MLST) or a high resolution melting-based MLST surrogate (Minim typing). These data were combined with MLST data from other studies on NT S. pyogenes to yield a set of 731 MLST or Minim typed isolates for analysis. goeBURST analysis of MLST allelic profiles and neighbour-joining trees of the MLST allele sequences revealed that a large proportion of the known global S. pyogenes MLST-defined diversity has now been found in the NT. Specifically, fully sequence typed NT isolates encompass 19% of known S. pyogenes STs and 43% of known S. pyogenes MLST alleles. These analyses provided no evidence for major NT-endemic strains, with many STs and MLST alleles shared between the NT and the rest of the world. The relationship between the number of known Minim types, and the probability that a Minim type identified in a calendar year would be novel was determined. This revealed that Minim types typically persist in the NT for >1 year, and indicate that the majority of NT Minim types have been identified. This study revealed that many diverse S. pyogenes strains exhibit global scale mobility that extends to isolated populations. The burden of S. pyogenes disease in the NT is unlikely to be due to the nature of NT S. pyogenes strains, but is rather a function of social and living conditions. PMID:24066079
Towers, Rebecca J; Carapetis, Jonathan R; Currie, Bart J; Davies, Mark R; Walker, Mark J; Dougan, Gordon; Giffard, Philip M
Streptococcal toxic shock syndrome (STSS) caused by Streptococcus pyogenes is a clinical condition with a high mortality rate despite modern intensive care. A key feature of STSS is excessive plasma leakage leading to hypovolemic hypotension, disturbed microcirculation and multiorgan failure. Previous work has identified a virulence mechanism in STSS where M1 protein of S. pyogenes forms complexes with fibrinogen that activate neutrophils to release heparin-binding protein (HBP), an inducer of vascular leakage. Here, we report a marked inter-individual difference in the response to M1 protein–induced HBP release, a difference found to be related to IgG antibodies directed against the central region of the M1 protein. To elicit massive HBP release, such antibodies need to be part of the M1 protein–fibrinogen complexes. The data add a novel aspect to bacterial pathogenesis where antibodies contribute to the severity of disease by promoting a pathologic inflammatory response.
Kahn, Fredrik; Morgelin, Matthias; Shannon, Oonagh; Norrby-Teglund, Anna; Herwald, Heiko; Olin, Anders I.; Bjorck, Lars
We recently developed a method that allows fast differentiation between Streptococcus pyogenes (GAS) strains. The method named phage profiling (PP) is based on a simple assumption that a regular PCR reaction with Taq polymerase and relatively short elongation time is not able to yield long DNA fragment, such as ~40-50 kb integrated prophage. Only fragments without any integrated DNA or short fragments inserted between integration sites can be efficiently amplified. We designed primers that anneal upstream and downstream prophage integration sites, so in simple PCR reaction we can test if any additional DNA is integrated into particular site. Profiling of integrated elements can be used as rapid, high resolution typing method, with the resolution as high as PFGE and is excellent predictor of PFGE type. PMID:23076280
Borek, Anna L; Obsza?ska, Katarzyna; Hryniewicz, Waleria; Sitkiewicz, Izabela
Objective(s): Streptokinase (SKa) is an antigenic protein which is secreted by Streptococcus pyogenes. Streptokinase induces inflammation by complement activation, which may play a role in post infectious diseases. In the present study, recombinant streptokinase from S. pyogenes was produced and showed that recombinant SKa protein was recognized by infected human sera using Western blot analysis. Materials and Methods: In this study, the ska gene from S. pyogenes was amplified and cloned into pET32a which is a prokaryotic expression vector. pET32a-ska was transformed to Escherichia coli BL21 (DE3) pLysS and gene expression was induced by IPTG. Protein production was improved by modification of composition of the bacterial culture media and altering the induction time by IPTG. The expressed protein was purified by affinity chromatography using the Ni-NTA resin. The integrity of the product was confirmed by Westernblot analysis using infected mice. Serum reactivity of five infected individuals was further analyzed against the recombinant SKa protein. Results: Data indicated that recombinant SKa protein from S. pyogenes can be recognized by patient and mice sera. The concentration of the purified recombinant protein was 3.2 mg/L of initial culture. The highest amount of the expressed protein after addition of IPTG was obtained in a bacterial culture without glucose with the culture optical density of 0.8 (OD600 = 0.8). Conclusion : Present data shows, recombinant SKa protein has same epitopes with natural form of this antigen. Recombinant SKa also seemed to be a promising antigen for the serologic diagnosis of S. pyogenes infections.
Molaee, Neda; Abtahi, Hamid; Mosayebi, Ghasem
While many virulence factors promoting Streptococcus pyogenes invasive disease have been described, specific streptococcal factors and host properties influencing asymptomatic mucosal carriage remain uncertain. To address the need for a refined model of prolonged S. pyogenes asymptomatic mucosal colonization, we have adapted a preestrogenized murine vaginal colonization model for S. pyogenes. In this model, derivatives of strains HSC5, SF370, JRS4, NZ131, and MEW123 established a reproducible, asymptomatic colonization of the vaginal mucosa over a period of typically 3 to 4 weeks' duration at a relatively high colonization efficiency. Prior treatment with estradiol prolonged streptococcal colonization and was associated with reduced inflammation in the colonized vaginal epithelium as well as a decreased leukocyte presence in vaginal fluid compared to the levels of inflammation and leukocyte presence in non-estradiol-treated control mice. The utility of our model for investigating S. pyogenes factors contributing to mucosal carriage was verified, as a mutant with a mutation in the transcriptional regulator catabolite control protein A (CcpA) demonstrated significant impairment in vaginal colonization. An assessment of in vivo transcriptional activity in the CcpA? strain for several known CcpA-regulated genes identified significantly elevated transcription of lactate oxidase (lctO) correlating with excessive generation of hydrogen peroxide to self-lethal levels. Deletion of lctO did not impair colonization, but deletion of lctO in a CcpA? strain prolonged carriage, exceeding even that of the wild-type strain. Thus, while LctO is not essential for vaginal colonization, its dysregulation is deleterious, highlighting the critical role of CcpA in promoting mucosal colonization. The vaginal colonization model should prove effective for future analyses of S. pyogenes mucosal colonization.
Watson, Michael E.; Nielsen, Hailyn V.; Hultgren, Scott J.
Diseases resulting from infection by group A streptococcus (GAS) are an increasing burden on global health. A novel vaccine was developed targeting infection by Streptococcus pyogenes. The vaccine incorporates a recombinant fusion protein antigen (SpeAB) which was engineered by combining inactive mutant forms of streptococcal pyrogenic exotoxin A (SpeA) and streptococcal pyrogenic exotoxin B (SpeB) from S. pyogenes. A rational, scientific approach to vaccine development was utilized to determine optimal formulation conditions with aluminum adjuvants. Investigations of the pH stability profile of SpeAB concluded the antigen was most stable near pH 8. Incorporation of the stabilizers sucrose and mannitol significantly enhanced the stability of the antigen. Vaccines were formulated in which most of the SpeAB was adsorbed to the adjuvant or remained in solution. A SpeAB vaccine formulation, stabilized with sucrose, in which the antigen remains adsorbed to the aluminum adjuvant retained the greatest potency as determined by evaluation of neutralizing antibody responses in mice. This vaccine has great potential to provide a safe and effective method for prevention of GAS disease. PMID:24837509
Morefield, Garry; Touhey, Graham; Lu, Fangjia; Dunham, Anisa; HogenEsch, Harm
Among nonhemolytic Streptococcus pyogenes (group A streptococcus) strains (n = 9) isolated from patients with pharyngitis or acute otitis media, we identified three deletions in the region from the epf gene, encoding the extracellular matrix binding protein, to the sag operon, mediating streptolysin S production.
Yoshino, Miho; Murayama, Somay Y.; Sunaoshi, Katsuhiko; Wajima, Takeaki; Takahashi, Miki; Masaki, Junko; Kurokawa, Iku; Ubukata, Kimiko
Background The production of Streptococcus pyogenes exoproteins, many of which contribute to virulence, is regulated in response to nutrient availability. CodY is a transcriptional regulator that controls gene expression in response to amino acid availability. The purpose of this study was to identify differences in the expression of streptococcal exoproteins associated with deletion of the codY gene. Results We compared the secreted proteins produced by wild-type S. pyogenes to a codY mutant in the post-exponential phase of growth. We used both one and two-dimensional gel electrophoresis to separate exoproteins. Proteins that were significantly different in abundance upon repeated analysis were identified with tandem mass spectrometry. The production of the secreted cysteine protease SpeB, a secreted chromosomally encoded nuclease (SdaB), and a putative adhesion factor (Spy49_0549) were more abundant in supernatant fluids obtained from the codY mutant. In addition, hyaluronidase (HylA), CAMP factor (Cfa), a prophage encoded nuclease (Spd-3), and an uncharacterized extracellular protein (Spy49_0015) were less abundant in supernatant fluids obtained from the codY mutant strain. Enzymatic assays showed greater DNase activity in culture supernatants isolated in the post-exponential phase of growth from the codY mutant strain compared to the wild-type strain. Because extracellular nucleases and proteases can influence biofilm formation, we also measured the ability of the strains to form biofilms during growth with both rich medium (Todd Hewitt yeast extract; THY) and chemically defined media (CDM). No difference was observed with rich media but with CDM the biofilms formed by the codY mutant strain had less biomass compared to the wild-type strain. Conclusions Overall, the results indicate that CodY alters the abundance of a select group of S. pyogenes exoproteins, including DNases, a protease, and hylauronidase, which together may alleviate starvation by promoting dissemination of the pathogen to nutrient rich environments and by hydrolysis of host macromolecules.
Explosive outbreaks of infectious diseases occasionally occur without immediately obvious epidemiological or microbiological explanations. Plague, cholera and Streptococcus pyogenes infection are some of the epidemic-prone bacterial infections. Besides epidemiological and conventional microbiological methods, the next-generation gene sequencing technology permits prompt detection of genomic and transcriptomic profiles associated with invasive phenotypes. Horizontal gene transfer due to mobile genetic elements carrying virulence factors and antimicrobial resistance, or mutations associated with the two component CovRS operon are important bacterial factors conferring survival advantage or invasiveness. The high incidence of scarlet fever in children less than 10 years old suggests that the lack of protective immunity is an important host factor. A high population density, overcrowded living environment and a low yearly rainfall are environmental factors contributing to outbreak development. Inappropriate antibiotic use is not only ineffective for treatment, but may actually drive an epidemic caused by drug-resistant strains and worsen patient outcomes by increasing the bacterial density at the site of infection and inducing toxin production. Surveillance of severe S. pyogenes infection is important because it can complicate concurrent chickenpox and influenza. Concomitant outbreaks of these two latter infections with a highly virulent and drug-resistant S. pyogenes strain can be disastrous.
Wong, Samson SY; Yuen, Kwok-Yung
The hemolytic Streptococcus pyogenes can use a variety of heme compounds as an iron source. In this study, we investigate hemoprotein utilization by S. pyogenes. We demonstrate that surface proteins contribute to the binding of hemoproteins to S. pyogenes. We identify an ABC transporter from the iron complex family named sia for streptococcal iron acquisition, which consists of a lipoprotein
Christopher S. Bates; Griselle E. Montanez; Charles R. Woods; Rebecca M. Vincent; Zehava Eichenbaum
Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as ‘trademark’ virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ?10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC –II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms.
Kasper, Katherine J.; Zeppa, Joseph J.; Wakabayashi, Adrienne T.; Xu, Stacey X.; Mazzuca, Delfina M.; Welch, Ian; Baroja, Miren L.; Kotb, Malak; Cairns, Ewa; Cleary, P. Patrick; Haeryfar, S. M. Mansour; McCormick, John K.
The pathogenic bacteria Streptococcus pyogenes can cause an array of diseases in humans, including moderate infections such as pharyngitis (strep throat) as well as life threatening conditions such as necrotizing fasciitis and puerperal fever. The antigen I/II family proteins are cell wall anchored adhesin proteins found on the surfaces of most oral streptococci and are involved in host colonization and biofilm formation. In the present study we have determined the crystal structure of the C2–3-domain of the antigen I/II type protein AspA from S. pyogenes M type 28. The structure was solved to 1.8 Å resolution and shows that the C2–3-domain is comprised of two structurally similar DEv-IgG motifs, designated C2 and C3, both containing a stabilizing covalent isopeptide bond. Furthermore a metal binding site is identified, containing a bound calcium ion. Despite relatively low sequence identity, interestingly, the overall structure shares high similarity to the C2–3-domains of antigen I/II proteins from Streptococcus gordonii and Streptococcus mutans, although certain parts of the structure exhibit distinct features. In summary this work constitutes the first step in the full structure determination of the AspA protein from S. pyogenes.
Hall, Michael; Nylander, ?sa; Jenkinson, Howard F.; Persson, Karina
Streptococcus pyogenes Rgg is a regulatory protein that controls the transcription of 588 genes in strain NZ131 during the post-exponential phase of growth, including the virulence-associated genes encoding the extracellular SpeB protease, pullulanase A (PulA), and two extracellular nucleases (SdaB and Spd-3). Rgg binds to DNA proximally to the speB promoter (PspeB) to activate transcription; however, it is not known if Rgg binds to the promoters of other genes to influence expression, or if the perturbation of other global regulons accounts for the genome-wide changes in expression associated with the mutant. To address this issue, chromatin immunoprecipitation followed by DNA microarray analysis (ChIP-chip) was used to identify the DNA binding sites of Rgg. Rgg bound to 65 sites in the chromosome. Thirty-five were within noncoding DNA, and 43% of these were adjacent to genes previously identified as regulated by Rgg. Electrophoretic mobility shift assays were used to assess the binding of Rgg to a subset of sites bound in vivo, including the noncoding DNA upstream of speB, the genes encoding PulA, Spd-3, and a transcriptional regulator (SPY49_1113), and prophage-associated genes encoding a putative integrase (SPY49_0746) and a surface antigen (SPY49_0396). Rgg bound to all target DNAs in vitro, consistent with the in vivo results. Finally, analyses with a transcriptional reporter system showed that the DNA bound by Rgg contained an active promoter that was regulated by Rgg. Overall, the results indicate that Rgg binds specifically to multiple sites in the chromosome, including prophage DNA, to influence gene expression.
Anbalagan, Srivishnupriya; McShan, W. Michael; Dunman, Paul M.; Chaussee, Michael S.
There are few studies reporting pyogenic liver abscess (PLA) caused by Streptococcus constellatus in the medical literature. S. constellatus is a comensal microorganism that belongs to the Streptococcus milleri's bacteria group and is not considered to be pathogenic for humans. We report the case of a 23-year-old man with a 15-days history of abdominal pain in the right flank followed by daily fever, chills, nausea, vomits, sialism and jaundice. Physical examination revealed moderate jaundice (2+/4+), abdominal distention, generalized pain and tender over the right flank with positive Blumberg's sign. Additionally, the liver was palpable 5 cm below the costal margin in the right midclavicular line. Abdominal Computerized Tomography showed multiple hypodense hepatic images suggestive of liver abscesses. The patient underwent surgical exploration of the abdomen through a sub-costal incision and, during operation ruptured abscess localized on the hepatic segment III was drained. Culture of the purulent material obtained at surgery yielded Streptococcus constellatus as the causative agent. Liver abscess is a potential life-threatening disease that must be treated as soon as possible with invasive approaches, if necessary, and bacteriological studies performed when possible, allowing isolation of causative agents and specific antibiotic therapy. PMID:19841508
Rodrigues, André Luiz Santos; Soares, Manoel C P; Ramos, Francisco L P; Crociati Meguins, Lucas
Streptococcus pyogenes is an important pathogen that causes a variety of diseases. The most common infections involve the throat (pharyngitis) or skin (impetigo); however, the factors that determine tissue tropism and severity are incompletely understood. The S. pyogenes NAD+ glycohydrolase (SPN) is a virulence factor that has been implicated in contributing to the pathogenesis of severe infections. However, the role of SPN in determining the bacterium's tissue tropism has not been evaluated. In this report, we examine the sequences of spn and its endogenous inhibitor ifs from a worldwide collection of S. pyogenes strains. Analysis of average pairwise nucleotide diversity, average number of nucleotide differences, and ratio of nonsynonymous to synonymous substitutions revealed significant diversity in spn and ifs. Application of established models of molecular evolution shows that SPN is evolving under positive selection and diverging into NAD+ glycohydrolase (NADase)-active and -inactive subtypes. Additionally, the NADase-inactive SPN subtypes maintain the characteristics of a functional gene while ifs becomes a pseudogene. Thus, NADase-inactive SPN continues to evolve under functional constraint. Furthermore, NADase activity did not correlate with invasive disease in our collection but was associated with tissue tropism. The ability to cause infection at both the pharynx and the skin (“generalist” strains) is correlated with NADase-active SPN, while the preference for causing infection at either the throat or the skin (“specialist” strains) is associated with NADase-inactive SPN. These findings suggest that SPN has a NADase-independent function and prompt a reevaluation of the role of SPN in streptococcal pathogenesis.
Riddle, David J.; Bessen, Debra E.; Caparon, Michael G.
Background Collagen has proved valuable as biomedical materials for a range of clinical applications, particularly in wound healing. It is normally produced from animal sources, such as from bovines, but concerns have emerged over transmission of diseases. Recombinant collagens would be preferable, but are difficult to produce. Recently, studies have shown that ‘collagens’ from bacteria, including Streptococcus pyogenes, can be produced in the laboratory as recombinant products, and that these are biocompatible. In the present study we have established that examples of bacterial collagens can be produced in a bioreactor with high yields providing proof of manufacture of this important group of proteins. Results Production trials in shake flask cultures gave low yields of recombinant product, < 1 g/L. Increased yields, of around 1 g/L, were obtained when the shake flask process was transferred to a stirred tank bioreactor, and the yield was further enhanced to around 10 g/L by implementation of a high cell density fed-batch process and the use of suitably formulated fully defined media. Similar yields were obtained with 2 different constructs, one containing an introduced heparin binding domain. The best yields, of up to 19 g/L were obtained using this high cell density strategy, with an extended 24 h production time. Conclusions These data have shown that recombinant bacterial collagen from S. pyogenes, can be produced in sufficient yield by a scalable microbial production process to give commercially acceptable yields for broad use in biomedical applications.
Extracellular High Mobility Group Box 1 (HMGB1) has been associated with acute and chronic inflammatory conditions. However, little is known about HMGB1 in necrotizing bacterial infections. We hypothesized that the local HMGB1 response is excessive in severe soft tissue infections (STIs), which are characterized by necrosis and hyperinflammation. To explore this, tissue biopsies were collected from patients with varying severity of Streptococcus pyogenes skin and STIs, including erysipelas, cellulitis, and necrotizing fasciitis. Tissue sections were immunostained for HMGB1, S. pyogenes, and inflammatory cell infiltrates and results quantified by acquired computerized image analysis (ACIA). HMGB1 expression increased in parallel to disease severity and was significantly higher in necrotizing fasciitis than in erysipelas (p = 0.0023). Confocal microscopy of sections co-stained for HMGB1 and cell markers revealed both extracellular and cytoplasmic HMGB1, the latter of which was found predominantly in macrophages. To further verify macrophages as main source of activation triggered HMGB1 release, human macrophages were infected with clinical S. pyogenes isolates. The results demonstrated infection triggered release of HMGB1. Dual staining's visualized HMGB1 in areas close to, but not overlapping, with neutrophils, indicating a potential chemotactic role. In vitro transmigration experiments showed a chemotactic effect of HMGB1 on neutrophils. The data furthermore provided in vivo support that HGMB1 may form immunostimulatory complexes with IL-1?. Taken together, the findings provide the first in vivo evidence that HMGB1 is abundant at the local site of severe bacterial STIs and its levels correlated to severity of infections; hence, indicating its potential value as a biomarker for tissue pathology.
Johansson, Linda; Snall, Johanna; Sendi, Parham; Linner, Anna; Thulin, Pontus; Linder, Adam; Treutiger, Carl-Johan; Norrby-Teglund, Anna
Opsonization of bacteria by complement proteins is an important component of the immune response. The pathogenic bacterium Streptococcus pyogenes has evolved multiple mechanisms for the evasion of complement- mediated opsonization. One mechanism involves the binding of human regulators of complement activation such as factor H (FH) and FH-like protein 1 (FHL-1). Acquisition of these regulatory proteins can limit deposition of
Vinod Pandiripally; Eugene Gregory; David Cue
We studied the evolution of susceptibility of Streptococcus pyogenes isolated in our hospital from 1987 to 1996. Susceptibility to penicillin, ampicillin, cefotaxime, cefuroxime, imipenem, erythromycin, clindamycin, tetracycline, vancomycin, ciprofloxacin, rifampin, and chloramphenicol was determined by the National Committee for Clinical Laboratory Standards broth microdilution method. Differentiation of phenotypes of erythromycin-resistant strains was performed using the double-disc method. All isolates remained
Carmen Betriu; M. Carmen Casado; María Gómez; Ana Sanchez; M. Luisa Palau; Juan J Picazo
We present the draft genome sequences of nine clinical Streptococcus pyogenes isolates recovered from patients suffering from sore throat and skin infections. An average of 2,454,334 paired-end reads per sample were generated, which assembled into 21 to 198 contigs, with a G+C content of 38.4 to 38.5%.
Eisen, Jonathan A.; Jospin, Guillaume; Coil, David A.
We present the draft genome sequences of nine clinical Streptococcus pyogenes isolates recovered from patients suffering from sore throat and skin infections. An average of 2,454,334 paired-end reads per sample were generated, which assembled into 21 to 198 contigs, with a G+C content of 38.4 to 38.5%. PMID:24831139
Tokajian, Sima; Eisen, Jonathan A; Jospin, Guillaume; Coil, David A
Streptococcus pyogenes is responsible for infections as pharyngitis, sepsis, necrotizing fasciitis and streptococcal toxic shock syndrome. The M protein is the major bacterial antigen and consists of both polymorphic N-terminal portion and a conserved region. In the present study, we analyzed the in vitro ability of StreptInCor a C-terminal candidate vaccine against S. pyogenes to induce antibodies to neutralize/opsonize the most common S. pyogenes strains in Sao Paulo by examining the recognition by sera from StreptInCor immunized mice. We also evaluated the presence of cross-reactive antibodies against human heart valve tissue. Anti-StreptInCor antibodies were able to neutralize/opsonize at least 5 strains, showing that immunization with StreptInCor is effective against several S. pyogenes strains and can prevent infection and subsequent sequelae without causing autoimmune reactions. PMID:23994376
De Amicis, Karine M; Freschi de Barros, Samar; Alencar, Raquel E; Postól, Edilberto; Martins, Carlo de Oliveira; Arcuri, Helen Andrade; Goulart, Cibelly; Kalil, Jorge; Guilherme, Luiza
Streptococcus pyogenes (group A streptococcus [GAS]) is a human-specific pathogen that causes a variety of diseases ranging from superficial infections to life-threatening diseases. SpeB, a potent extracellular cysteine proteinase, plays an important role in the pathogenesis of GAS infections. Previous studies show that SpeB expression and activity are controlled at the transcriptional and posttranslational levels, though it had been unclear whether speB was also regulated at the posttranscriptional level. In this study, we examined the growth phase-dependent speB mRNA level and decay using quantitative reverse transcription-PCR (qRT-PCR) and Northern blot analyses. We observed that speB mRNA accumulated rapidly during exponential growth, which occurred concomitantly with an increase in speB mRNA stability. A closer observation revealed that the increased speB mRNA stability was mainly due to progressive acidification. Inactivation of RNase Y, a recently identified endoribonuclease, revealed a role in processing and degradation of speB mRNA. We conclude that the increased speB mRNA stability contributes to the rapid accumulation of speB transcript during growth.
Itzek, Andreas; Malke, Horst; Ferretti, Joseph J.
The pathogenesis of acute rheumatic fever (ARF) is poorly understood. We identified two contiguous bacteriophage genes, designated speL and speM, encoding novel inferred superantigens in the genome sequence of an ARF strain of serotype M18 group A streptococcus (GAS). speL and speM were located at the same genomic site in 33 serotype M18 isolates, and no nucleotide sequence diversity was
Laura M. Smoot; John K. McCormick; James C. Smoot; Nancy P. Hoe; Ian Strickland; Robert L. Cole; Kent D. Barbian; Cathleen A. Earhart; Douglas H. Ohlendorf; L. George Veasy; Harry R. Hill; Donald Y. M. Leung; Patrick M. Schlievert; James M. Musser
Group A streptococcus (GAS) causes a wide range of human diseases, including bacterial arthritis. The pathogenesis of arthritis is characterized by synovial proliferation and the destruction of cartilage and subchondral bone in joints. We report here that GAS strain JRS4 invaded a chondrogenic cell line ATDC5 and induced the degradation of the extracellular matrix (ECM), whereas an isogenic mutant of JRS4 lacking a fibronectin-binding protein, SAM1, failed to invade the chondrocytes or degrade the ECM. Reverse transcription-PCR and Western blot analysis revealed that the expression of matrix metalloproteinase (MMP)-13 was strongly elevated during the infection with GAS. A reporter assay revealed that the activation of the AP-1 transcription factor and the phosphorylation of c-Jun terminal kinase participated in MMP-13 expression. These results suggest that MMP-13 plays an important role in the destruction of infected joints during the development of septic arthritis.
Sakurai, Atsuo [Division of Bacteriology, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Okahashi, Nobuo [Oral Frontier Biology, Osaka University Graduate School of Dentistry, Suita-Osaka 565-0871 (Japan); Maruyama, Fumito [Division of Bacteriology, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Ooshima, Takashi [Pediatric Dentistry, Osaka University Graduate School of Dentistry, Suita-Osaka 565-0871 (Japan); Hamada, Shigeyuki [Advanced Research Institute for the Sciences and Humanities, Nihon University, 6F Ichigaya Tokyu Building, 2-1 Kudan-kita 4-chome, Chiyoda-ku, Tokyo 102-0073 (Japan); Nakagawa, Ichiro [Division of Bacteriology, Department of Infectious Disease Control, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan)], E-mail: email@example.com
During a 6-month period, 95 invasive infections due to Streptococcus pyogenes and group C or group G Streptococcus dysgalactiae subsp. equisimilis were recorded from 40 centers of 16 cities in Argentina. We describe here epidemiologic data available for 55 and 19 patients, respectively, associated with invasive infections due to S. pyogenes and S. dysgalactiae subsp. equisimilis. The associated isolates and 58 additional pharyngeal isolates were genotyped and subjected to serologic and/or antibiotic susceptibility testing. Group A streptococcal emm type distribution and strain association with toxic shock appeared to differ somewhat from results found within the United States; however, serologic characterization and sof sequence typing suggested that emm types found in both countries are reflective of shared clonal types.
Lopardo, Horacio A.; Vidal, Patricia; Sparo, Monica; Jeric, Paola; Centron, Daniela; Facklam, Richard R.; Paganini, Hugo; Pagniez, N. Gaston; Lovgren, Marguerite; Beall, Bernard
In a nationwide study in Germany covering 13 clinical microbiology laboratories, a total of 307 Streptococcus pyogenes (mainly pharyngitis) and 333 Streptococcus pneumoniae (respiratory tract infections) strains were collected from outpatients less than 16 years of age. The MICs of penicillin G, amoxicillin, cefotaxime, erythromycin A, clindamycin, levofloxacin, and telithromycin were determined by the microdilution method. In S. pyogenes isolates, resistance rates were as follows: penicillin, 0%; erythromycin A, 13.7%; and levofloxacin, 0%. Telithromycin showed good activity against S. pyogenes isolates (MIC90 = 0.25 ?g/ml; MIC range, 0.016 to 16 ?g/ml). Three strains were found to be telithromycin-resistant (MIC ? 4 ?g/ml). Erythromycin-resistant strains were characterized for the underlying resistance genotype, with 40.5% having the efflux type mef(A), 38.1% having the erm(A), and 9.5% having the erm(B) genotypes. emm typing of macrolide-resistant S. pyogenes isolates showed emm types 4 (45.2%), 77 (26.2%), and 12 (11.9%) to be predominant. In S. pneumoniae, resistance rates were as follows: penicillin intermediate, 7.5%; penicillin resistant, 0%; erythromycin A, 17.4%; and levofloxacin, 0%. Telithromycin was highly active against pneumococcal isolates (MIC90 ? 0.016 ?g/ml; range, 0.016 to 0.5 ?g/ml). The overall resistance profile of streptococcal respiratory tract isolates is still favorable, but macrolide resistance is of growing concern in Germany.
Reinert, Ralf Rene; Lutticken, Rudolf; Bryskier, Andre; Al-Lahham, Adnan
Background & objectives: Subinhibitory concentrations (sub-MICs) of antibiotics, although not able to kill bacteria, but influence bacterial virulence significantly. Fluoroquinolones (FQs) which are used against other bacterial pathogens creates resistance in non-targeted Streptococcus pyogenes. This study was undertaken to characterize the effect of sub-MICs of FQs on S. pyogenes biofilm formation. Methods: Biofilm forming six M serotypes M56, st38, M89, M65, M100 and M74 of S. pyogenes clinical isolates were challenged against four FQs namely, ciprofloxacin, ofloxacin, levofloxacin and norfloxacin. The antibiofilm potential of these FQs was analysed at their subinhibitory concentrations (1/2 to 1/64 MIC) using biofilm assay, XTT reduction assay, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results: Among the four FQs tested, ofloxacin and levofloxacin at 1/2 MIC showed the maximum inhibition (92%) of biofilm formation against M56 and M74 serotypes. FQs effectively interfered in the microcolony formation of S. pyogenes isolates at 1/2 to 1/8 sub-MICs. Inhibition of biofilm formation was greatly reduced beyond 1/16 MICs and allowed biofilm formation. XTT reduction assay revealed the increase in metabolic activity of S. pyogenes biofilm against the decrease in FQs concentration. SEM and CLSM validated the potential of sub-MICs of FQs against the six S. pyogenes. Interpretation & conclusions: Our results showed that the inhibitory effect all four FQs on S. pyogenes biofilm formation was concentration dependent. FQs at proper dosage can be effective against S. pyogenes and lower concentrations may allow the bacteria to form barriers against the antibiotic in the form of biofilm. PMID:23760384
Balaji, Kannan; Thenmozhi, Ramalingam; Pandian, Shunmugiah Karutha
Background & objectives: Subinhibitory concentrations (sub-MICs) of antibiotics, although not able to kill bacteria, but influence bacterial virulence significantly. Fluoroquinolones (FQs) which are used against other bacterial pathogens creates resistance in non-targeted Streptococcus pyogenes. This study was undertaken to characterize the effect of sub-MICs of FQs on S. pyogenes biofilm formation. Methods: Biofilm forming six M serotypes M56, st38, M89, M65, M100 and M74 of S. pyogenes clinical isolates were challenged against four FQs namely, ciprofloxacin, ofloxacin, levofloxacin and norfloxacin. The antibiofilm potential of these FQs was analysed at their subinhibitory concentrations (1/2 to 1/64 MIC) using biofilm assay, XTT reduction assay, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results: Among the four FQs tested, ofloxacin and levofloxacin at 1/2 MIC showed the maximum inhibition (92%) of biofilm formation against M56 and M74 serotypes. FQs effectively interfered in the microcolony formation of S. pyogenes isolates at 1/2 to 1/8 sub-MICs. Inhibition of biofilm formation was greatly reduced beyond 1/16 MICs and allowed biofilm formation. XTT reduction assay revealed the increase in metabolic activity of S. pyogenes biofilm against the decrease in FQs concentration. SEM and CLSM validated the potential of sub-MICs of FQs against the six S. pyogenes. Interpretation & conclusions: Our results showed that the inhibitory effect all four FQs on S. pyogenes biofilm formation was concentration dependent. FQs at proper dosage can be effective against S. pyogenes and lower concentrations may allow the bacteria to form barriers against the antibiotic in the form of biofilm.
Balaji, Kannan; Thenmozhi, Ramalingam; Pandian, Shunmugiah Karutha
Genes encoding one or more Ser/Thr protein kinases have been identified recently in many bacteria, including one (stk) in the human pathogen Streptococcus pyogenes (group A streptococcus [GAS]). We report that in GAS, stk is required to produce disease in a murine myositis model of infection. Using microarray and quantitative reverse transcription-PCR (qRT-PCR) studies, we found that Stk activates genes for virulence factors, osmoregulation, metabolism of ?-glucans, and fatty acid biosynthesis, as well as genes affecting cell wall synthesis. Confirming these transcription studies, we determined that the stk deletion mutant is more sensitive to osmotic stress and to penicillin than the wild type. We discuss several possible Stk phosphorylation targets that might explain Stk regulation of expression of specific operons and the possible role of Stk in resuscitation from quiescence.
Bugrysheva, Julia; Froehlich, Barbara J.; Freiberg, Jeffrey A.; Scott, June R.
The lack of epidemiologic data on invasive Streptococcus pyogenes infections in many developing countries is concerning, as S. pyogenes infections are commonly endemic in these areas. Here we present the results of the first prospective surveillance study of invasive Streptococcus pyogenes infections in India. Fifty-four patients with invasive S. pyogenes infections were prospectively enrolled at two study sites, one in the north and one in the south of India. Sterile-site isolates were collected, and clinical information was documented using a standardized questionnaire. Available acute-phase sera were tested for their ability to inhibit superantigens produced by the patient's own isolate using a cell-based neutralizing assay. The most common clinical presentations were bacteremia without focus (30%), pneumonia (28%), and cellulitis (17%). Only two cases of streptococcal toxic shock syndrome and no cases of necrotizing fasciitis were identified. Characterization of the isolates revealed great heterogeneity, with 32 different emm subtypes and 29 different superantigen gene profiles being represented among the 49 sterile-site isolates. Analyses of acute-phase sera showed that only 20% of the cases in the north cohort had superantigen-neutralizing activity in their sera, whereas 50% of the cases from the south site had neutralizing activity. The results demonstrate that there are important differences in both clinical presentation and strain characteristics between invasive S. pyogenes infections in India and invasive S. pyogenes infections in Western countries. The findings underscore the importance of epidemiologic studies on streptococcal infections in India and have direct implications for current vaccine developments.
Haggar, Axana; Nerlich, Andreas; Kumar, Rajesh; Abraham, Vinod J.; Brahmadathan, Kootallur N.; Ray, Pallab; Dhanda, Vanita; Joshua, John Melbin Jose; Mehra, Narinder; Bergmann, Rene; Chhatwal, G. Singh
The 1,852,442-bp sequence of an M1 strain of Streptococcus pyo- genes, a Gram-positive pathogen, has been determined and con- tains 1,752 predicted protein-encoding genes. Approximately one- third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of
Joseph J. Ferretti; William M. McShan; Dragana Ajdic; Dragutin J. Savic; Gorana Savic; Kevin Lyon; Charles Primeaux; Steven Sezate; Alexander N. Suvorov; Steve Kenton; Hong Shing Lai; Shao Ping Lin; Yudong Qian; Hong Gui Jia; Fares Z. Najar; Qun Ren; Hua Zhu; Lin Song; Jim White; Xiling Yuan; Sandra W. Clifton; Bruce A. Roe; Robert McLaughlin
A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1molL?1 HCl for methyl mercury and 2molL?1 HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical
Mustafa Tuzen; Ozgur Dogan Uluozlu; Isa Karaman; Mustafa Soylak
A physical map of the chromosome of an M type 1 strain of Streptococcus pyogenes was constructed following digestion with three different restriction enzymes, SmaI, SfiI, and SgrAI, and separation and analysis of fragments by pulsed-field gel electrophoresis. The genome size of this strain was estimated to be 1,920 kb. By employing Southern hybridization and PCR analysis, 36 genes were located on the map.
Suvorov, A N; Ferretti, J J
We evaluated the in vitro activity of sitafloxacin against Japanese clinical isolates of Streptococcus pyogenes by broth microdilution susceptibility testing and time-kill studies to elucidate its eradication potential against S. pyogenes. One hundred and nineteen clinical isolates of S. pyogenes isolated from pharynx were tested to sitafloxacin and seven other agents in the susceptibility testing. The time-kill studies were conducted with five strains, one of which was resistant to clarithromycin, one resistant to levofloxacin and one type strain of S. pyogenes. In the time-kill studies, sitafloxacin, garenoxacin, amoxicillin and clarithromycin were assessed at static concentrations of their respective peak concentrations in plasma (C(max)) when administered as oral single doses for adult patients with S. pyogenes infections. We found the rank order of antimicrobial activity against S. pyogenes isolates was: cefcapene (MIC90, 0.015 microg/mL) > amoxicillin (0.03 microg/mL) > sitafloxacin (0.12 microg/mL) > garenoxacin (0.25 microg/mL) > levofloxacin (4 microg/mL) > minocycline (16 microg/mL). Macrolide-resistant isolates accounted for 72 (60.5%), resulting in clarithromycin and azithromycin MIC90s of > 32 and > 128 microg/mL, respectively. Sitafloxacin exhibited the most rapid bactericidal activity (> or = log reduction from the initial inoculum) within 2h against all tested strains, including even one levofloxacin-resistant strain. For garenoxacin, bactericidal activity was achieved between 2 and 6 h. Amoxicillin revealed no significant bactericidal activity up to 6 h. Clarithromycin showed no bactericidal activity and did not inhibit growth of a clarithromycin-resistant strain. These data indicate the potential usefulness of sitafloxacin for the treatment of S. pyogenes eradication. PMID:24527519
Namba, Eiko; Okumura, Ryo; Chiba, Megumi; Hoshino, Kazuki; Tateda, Kazuhiro
Streptococcus pyogenes , also known as group A streptococcus (GAS), is a Gram positive human pathogen responsible for invasive and noninvasive human infections with a high incidence rate. Traditional detection methods involve cell culture and PCR, which are limited by long processing times or the need for high cost equipment. Impedance-based electrochemical immunosensors provide an alternative by which precise and rapid quantitative detection of the organism can help with rapid clinical decisions. To bring a biosensor for point-of-care applications to market, strict optimization of each level of construction and operation is required. In this paper, commercial screen-printed gold electrodes have been used to construct polytyramine (Ptyr)-based immunosensors. Biotin tagged whole antibodies against S. pyogenes were conjugated to Ptyr amine group via biotin-NeutrAvidin coupling. Sensors were optimized at each level of construction, particularly for Ptyr electrodeposition and antibody concentration, to optimize signal and specificity. Scanning electron microscopy, fluorescence microscopy, and on-sensor analysis (HRP conjugated enhanced chemiluminescence-based semiquantitative method) to detect Ptyr surface amine and bound antibody were performed as supporting techniques. Cumulative and single shot incubations had shown detection range of 100 to 10(5) cells per 10 ?L and 100 to 10(4) cells per 10 ?L of bacteria in PBS, respectively. Sensors were also able to specifically detect S. pyogenes in 50% (v/v) human saliva, with good selectivity and low cross-reactivity. PMID:24256123
Ahmed, Asif; Rushworth, Jo V; Wright, John D; Millner, Paul A
Fluoroquinolone resistance in Streptococcus pyogenes has been described only anecdotally. In this study we describe two invasive ciprofloxacin-resistant S. pyogenes isolates (ciprofloxacin MICs, 8 mg/liter), one of which shows evidence of interspecies recombination. The quinolone resistance-determining regions of gyrA and parC were sequenced. In both isolates, there was no evidence for an efflux pump and no mutation in gyrA. Both isolates had an S79F mutation in parC that is known to confer fluoroquinolone resistance. In addition, a D91N mutation in parC, which is not related to fluoroquinolone resistance but is a feature of the parC sequence of Streptococcus dysgalactiae, was found in one isolate. The parC nucleotide sequence of that isolate showed greater diversity than that of S. pyogenes. A GenBank search and phylogenetic analysis suggest that this isolate acquired resistance by horizontal gene transfer from S. dysgalactiae. Statistical testing for recombination confirmed interspecies recombination of a 90-bp sequence containing the S79F mutation from S. dysgalactiae. For the other isolate, we could confirm that it acquired resistance by spontaneous mutation by identifying the susceptible ancestor in an outbreak setting.
Pletz, M. W. R.; McGee, L.; Van Beneden, C. A.; Petit, S.; Bardsley, M.; Barlow, M.; Klugman, K. P.
Two fatal cases of Streptococcus pyogenes emm st22.6 bacteraemia occurred in a care home in England during April and June 2010, initiating a cluster investigation. The first case had left the home 13 days before the second case took up residence. We sought further cases and carriers. We swabbed throat and chronic skin lesions from residents and staff and examined these specimens for the presence of S. pyogenes. 61 specimens were taken from 18 of 19 residents and 39 of 39 staff. All results from swabbing were culture negative. We observed infection control practices and the environment at the care home for deficiencies. Issues were identified relating to the correct use of personal protective equipment, hand hygiene, clinical waste and laundry. Infection control practices were improved and training given. Infection control practices and the environment at a care home should be examined as part of the investigation of a S. pyogenes cluster. Screening for carriage of S. pyogenes should be done before antibiotic chemoprophylaxis is issued to care home residents and staff. PMID:22152707
Milne, L M; Lamagni, T; Efstratiou, A; Foley, C; Gilman, J; Lilley, M; Guha, S; Head, F; Han, T
This study is designed to evaluate the immune status of schoolchildren with respect to Streptococcus pyogenes, and to ascertain the usefulness of antideoxyribonuclease B (ADNase B). Antistreptolysin O (ASO) and ADNase B concentrations were measured quantitatively in 266 serum samples from healthy elementary school children in Seoul. Simultaneously, throat cultures were taken in order to isolate S. pyogenes and other beta-hemolytic streptococci (BHS). The upper limits of the normal (ULN) concentration of ASO and ADNase B were 326 IU/mL, and 362 IU/mL, respectively. The correlation between ADNase B (y) and ASO (x) was y=0.4x+173 (r=0.46). Mean ADNase B level (392 IU/mL) was significantly higher in children with S. pyogenes than in those with non-group A BHS (236 IU/mL) or no BHS (234 IU/ mL). Some schoolchildren were proven, via ASO and ADNase B tests, to be harboring asymptomatic S. pyogenes infections. The high ULN of ASO and ADNase B in schoolchildren should be carefully considered, in order to interpret the data collected from the patients. We could add the ADNase B test to our set of diagnostic tools, which would allow us to more accurately detect and diagnose streptococcal infections, as ADNase B was more specifically related to the results of throat cultures, and there was little correlation between ASO and ADNase B.
The transcriptional regulatory protein Rgg coordinates amino acid catabolism and virulence factor expres- sion in Streptococcus pyogenes. We used a proteomic approach to compare cytoplasmic proteins isolated from S. pyogenes wild-type strain NZ131 (serotype M49) to proteins isolated from an rgg mutant strain during the exponential and stationary phases of growth. Proteins were separated by two-dimensional gel electrophoresis, and 125
Michelle A. Chaussee; Eduardo A. Callegari; Michael S. Chaussee
The mitomycin C inducible prophage SF370.1 from the highly pathogenic M1 serotype Streptococcus pyogenes isolate SF370 showed a 41-kb-long genome whose genetic organization resembled that of SF11-like pac-site Siphoviridae. Its closest relative was prophage NIH1.1 from an M3 serotype S. pyogenes strain, followed by S. pneumoniae phage MM1 and Lactobacillus phage phig1e, Listeria phage A118, and Bacillus phage SPP1 in
Carlos Canchaya; Frank Desiere; W. Michael McShan; Joseph J. Ferretti; Julian Parkhill; Harald Brüssow
H-kininogen (high-molecular-mass kininogen, HK) is the precursor of the vasoactive peptide hormone bradykinin (BK). Previous work has demonstrated that HK binds to Streptococcus pyogenes through M-proteins, fibrous surface proteins and important virulence factors of these bacteria. Here we find that M-protein-expressing bacteria absorb HK from human plasma. The HK bound to the bacteria was found to be cleaved, and analysis of the degradation pattern suggested that the cleavage of HK at the bacterial surface is associated with the release of BK. Moreover, addition of activated plasma prekallikrein to bacteria preincubated with human plasma, resulted in BK release. This mechanism, by which a potent vasoactive and proinflammatory peptide is generated at the site of infection, should influence the host-parasite relationship during S. pyogenes infections.
Ben Nasr, A; Herwald, H; Sjobring, U; Renne, T; Muller-Esterl, W; Bjorck, L
Group A Streptococcus (GAS) is one of the major causes of respiratory tract infections. The objectives of this study were to identify isolates of S. pyogenes obtained from respiratory tract infections, and to assess their susceptibility to several antibiotics. A total of 40 strains were isolated and their susceptibility to 17 antibiotics was tested using a standard disk diffusion method. The minimum inhibitory concentrations (MICs) were determined using the E-test. All isolates were sensitive to ?-lactam antibiotics including penicillin, amoxicillin, and cephalosporins. Macrolides remain active with the exception of spiramycin, which showed reduced susceptibility. Out of the 40 isolates, 100% of the isolates were resistant to tetracycline. Interestingly, isolates were sensitive to chloramphenicol, teicoplanin, vancomycine, and levofloxacin, providing potential alternative choices of treatment against infections with S. pyogenes.
Camara, Makhtar; Dieng, Assane; Boye, Cheikh Saad Bouh
Virulent strains of Streptococcus pyogenes containing M protein were found to adhere well to human cheek epithelial cells in vitro, whereas an avirulent M - mutant strain adhered feebly. Pretreatment of M + strains with trypsin to remove their M protein surface coating or reacting them with type-specific antiserum markedly impaired their abilities to attach to epithelial cells. Electron microscopy revealed that the attachment of an M + strain to germfree rat epithelial cells was mediated by a fuzzy surface structure previously shown to contain M protein. When mixtures of streptomycin-resistant M + and M - strains were introduced into the mouths of mice, the proportions of the M + strain increased on tongue and cheek surfaces relative to its M - mutant. These data indicate that the surface fuzz of S. pyogenes which contains M protein functions in the attachment of the organism to epithelial surfaces, thereby permitting its colonization. PMID:4564883
Ellen, R P; Gibbons, R J
Background: CXC chemokines are induced by inflammatory stimuli in epithelial cells and some, like MIG\\/CXCL9, IP-10\\/ CXCL10 and I-TAC\\/CXCL11, are antibacterial for Streptococcus pyogenes. Methodology\\/Principal Findings: SpeB from S. pyogenes degrades a wide range of chemokines (i.e. IP10\\/CXCL10, I-TAC\\/ CXCL11, PF4\\/CXCL4, GROa\\/CXCL1, GROb\\/CXCL2, GROc\\/CXCL3, ENA78\\/CXCL5, GCP-2\\/CXCL6, NAP-2\\/CXCL7, SDF-1\\/CXCL12, BCA-1\\/CXCL13, BRAK\\/CXCL14, SRPSOX\\/CXCL16, MIP-3a\\/CCL20, Lymphotactin\\/XCL1, and Fractalkine\\/CX3CL1), has no activity on IL-8\\/CXCL8
Arne Egesten; Anders I. Olin; Helena M. Linge; Manisha Yadav; Matthias Mörgelin; Anna Karlsson; Mattias Collin
Horizontal gene transfer is an important means of bacterial evolution that is facilitated by transduction, conjugation, and natural genetic transformation. Transformation occurs after bacterial cells enter a state of competence, where naked DNA is acquired from the extracellular environment. Induction of the competent state relies on signals that activate master regulators, causing the expression of genes involved in DNA uptake, processing, and recombination. All streptococcal species contain the master regulator SigX and SigX-dependent effector genes required for natural genetic transformation; however, not all streptococcal species have been shown to be naturally competent. We recently demonstrated that competence development in Streptococcus mutans requires the type II ComRS quorum-sensing circuit, comprising an Rgg transcriptional activator and a novel peptide pheromone (L. Mashburn-Warren, D. A. Morrison, and M. J. Federle, Mol. Microbiol. 78:589–606, 2010). The type II ComRS system is shared by the pyogenic, mutans, and bovis streptococci, including the clinically relevant pathogen Streptococcus pyogenes. Here, we describe the activation of sigX by a small-peptide pheromone and an Rgg regulator of the type II ComRS class. We confirm previous reports that SigX is functional and able to activate sigX-dependent gene expression within the competence regulon, and that SigX stability is influenced by the cytoplasmic protease ClpP. Genomic analyses of available S. pyogenes genomes revealed the presence of intact genes within the competence regulon. While this is the first report to show natural induction of sigX, S. pyogenes remained nontransformable under laboratory conditions. Using radiolabeled DNA, we demonstrate that transformation is blocked at the stage of DNA uptake.
Mashburn-Warren, Lauren; Morrison, Donald A.
Many Gram-positive lactic acid bacteria (LAB) produce anti-bacterial peptides and small proteins called bacteriocins, which enable them to compete against other bacteria in the environment. These peptides fall structurally into three different classes, I, II, III, with class IIa being pediocin-like single entities and class IIb being two-peptide bacteriocins. Self-protective cognate immunity proteins are usually co-transcribed with these toxins. Several examples of cognates for IIa have already been solved structurally. Streptococcus pyogenes, closely related to LAB, is one of the most common human pathogens, so knowledge of how it competes against other LAB species is likely to prove invaluable. We have solved the crystal structure of the gene-product of locus Spy-2152 from S. pyogenes, (PDB: 2fu2), and found it to comprise an anti-parallel four-helix bundle that is structurally similar to other bacteriocin immunity proteins. Sequence analyses indicate this protein to be a possible immunity protein protective against class IIa or IIb bacteriocins. However, given that S. pyogenes appears to lack any IIa pediocin-like proteins but does possess class IIb bacteriocins, we suggest this protein confers immunity to IIb-like peptides. Combined structural, genomic and proteomic analyses have allowed the identification and in silico characterization of a new putative immunity protein from S. pyogenes, possibly the first structure of an immunity protein protective against potential class IIb two-peptide bacteriocins. We have named the two pairs of putative bacteriocins found in S. pyogenes pyogenecin 1, 2, 3 and 4.
Chang, C.; Coggill, P.; Bateman, A.; Finn, R.; Cymborowski, M.; Otwinowski, Z.; Minor, W.; Volkart, L.; Joachimiak, A.; Wellcome Trust Sanger Inst.; Univ. of Virginia; UT Southwestern Medical Center
Streptococcus pyogenes is an important pathogen that causes pharyngitis, sepsis, and rheumatic fever. Cell-associated streptococcal C5a peptidase (ScpA) protects S. pyogenes from phagocytosis and has been suggested to interrupt host defenses by enzymatically cleaving complement C5a, a major factor in the accumulation of neutrophils at sites of infection. How S. pyogenes recognizes and binds to C5a, however, is unclear. We detected a C5a-binding protein in 8 M urea extracts of S. pyogenes by ligand blotting using biotinylated C5a. Searching of genome databases showed that the C5a-binding protein is identical to the streptococcal plasmin receptor (Plr), also known as streptococcal surface dehydrogenase (SDH) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In the present study we identified a novel function of this multifunctional protein. Western blotting and immunofluorescence microscopy with anti-Plr/SDH/GAPDH showed that Plr/SDH/GAPDH is located on the bacterial surface and released into the culture supernatant. Next, we examined whether the streptococcal Plr/SDH/GAPDH inhibits the biological effects of C5a on human neutrophils. We found that soluble Plr/SDH/GAPDH inhibits C5a-activated chemotaxis and H2O2 production. Furthermore, our results suggested that soluble Plr/SDH/GAPDH captures C5a, inhibiting its chemotactic function. Also, cell-associated Plr/SDH/GAPDH and ScpA were both necessary for the cleavage of C5a on the bacterial surface. Together, these results indicate that the multifunctional protein Plr/SDH/GAPDH has additional functions that help S. pyogenes escape detection by the host immune system. PMID:16565520
Terao, Yutaka; Yamaguchi, Masaya; Hamada, Shigeyuki; Kawabata, Shigetada
Background Whole-cell matrix–assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) has been successfully applied for bacterial identification and typing of many pathogens. The fast and reliable qualities of MALDI-TOF MS make it suitable for clinical diagnostics. MALDI-TOF MS for the identification and cluster analysis of Streptococcus pyogenes, however, has not been reported. The goal of our study was to evaluate this approach for the rapid identification and typing of S. pyogenes. Methods 65 S. pyogenes isolates were obtained from the hospital. The samples were prepared and MALDI-TOF MS measurements were conducted as previously reported. Identification of unknown spectra was performed via a pattern recognition algorithm with a reference spectra and a dendrogram was constructed using the statistical toolbox in Matlab 7.1 integrated in the MALDI Biotyper 2.0 software. Results For identification, 61 of 65 S. pyogenes isolates could be identified correctly by MALDI-TOF MS with BioType 2.0 when compared to biochemical identification (API Strep), with an accuracy of 93.85%. In clustering analysis, 44 of 65 isolates were in accordance with those established by M typing, with a matching rate of 67.69%. When only the M type prevalence in China was considered, 41 of 45 isolates were in agreement with M typing, with a matching rate of 91.1%. Conclusions It was here shown that MALDI-TOF MS with Soft Biotype 2.0 and its database could facilitate rapid identification of S. pyogenes. It may present an attractive alternative to traditional biochemical methods of identification. However, for classification, more isolates and advances in the MALDI-TOF MS technology are needed to improve accuracy.
Hao, Huaijie; Kang, Lin; Zheng, Yuling; Jiang, Yongqiang; Jiang, Hua
Global regulation of virulence gene expression via transcriptional regulators plays a central role in the ability of the bacterial pathogen Streptococcus pyogenes (the group A Streptococcus, GAS) to rapidly adapt during infection. The 'stand-alone' regulators Mga, RofA-like proteins (RALPs), and RopB/Rgg control important and diverse virulence regulons in response to growth-related signals and other environmental conditions in GAS. Stand-alone regulated genes encode factors important for colonization of tissues, immune evasion, persistence, dissemination, metabolism, and the response to stressors. Although conserved 'core' regulons have been established for each, recent studies have revealed significant inter-serotype and even intra-serotype variation in the regulatory patterns presented by the stand-alone regulators. This chapter will look at each stand-alone regulatory pathway in depth and discuss how these important global networks influence virulence as well as interact with each other to produce an integrated response during GAS infection. PMID:19494581
McIver, Kevin S
A bacterium's ability to acquire nutrients from its host during infection is an essential component of pathogenesis. For the Gram-positive pathogen Streptococcus pyogenes, catabolism of the amino acid arginine via the arginine deiminase (ADI) pathway supplements energy production and provides protection against acid stress in vitro. Its expression is enhanced in murine models of infection, suggesting an important role in vivo. To gain insight into the function of the ADI pathway in pathogenesis, the virulence of mutants defective in each of its enzymes was examined. Mutants unable to use arginine (?ArcA) or citrulline (?ArcB) were attenuated for carriage in a murine model of asymptomatic mucosal colonization. However, in a murine model of inflammatory infection of cutaneous tissue, the ?ArcA mutant was attenuated but the ?ArcB mutant was hyperattenuated, revealing an unexpected tissue-specific role for citrulline metabolism in pathogenesis. When mice defective for the arginine-dependent production of nitric oxide (iNOS?/?) were infected with the ?ArcA mutant, cutaneous virulence was rescued, demonstrating that the ability of S. pyogenes to utilize arginine was dispensable in the absence of nitric oxide-mediated innate immunity. This work demonstrates the importance of arginine and citrulline catabolism and suggests a novel mechanism of virulence by which S. pyogenes uses its metabolism to modulate innate immunity through depletion of an essential host nutrient.
Cusumano, Zachary T.; Watson, Michael E.
Streptococcus pyogenes is a notorious human pathogen responsible for a wide array of infections. The ability of S. pyogenes to form biofilms is an innate property during the pathogenesis of invasive infections. From the eleven M serotypes tested: M56, M74, M100, M65, M89 and st38 formed dense biofilms in 48 h. The present study is the first of its kind to report about the biofilm formation in the serotypes M56, M65 M74 M100 and st38. XTT reduction assay of the biofilms showed decreased metabolic activity with increase in incubation time. The surface architecture of the biofilms when observed by scanning electron microscopy (SEM) revealed the microcolony formation. Confocal laser scanning microscopy (CLSM) was used to compare the surface topography and thickness of biofilms between the biofilm formers with and without the addition of glucose. Interestingly a non-biofilm former (st2147) was induced to form biofilms with the addition of glucose. On correlating the drug (erythromycin) resistance of the various M serotypes with their biofilm forming ability we noticed that erythromycin sensitive strains were found to be good biofilm formers. We also noticed that biofilm formation in S. pyogenes is independent of sil gene. PMID:21298675
Thenmozhi, Ramalingam; Balaji, Kannan; Kumar, Rajesh; Rao, Toleti Subba; Pandian, Shunmugiah Karutha
The Streptococcus pyogenes transcriptional regulator Rgg controls the expression of virulence-associated genes encoded both within the core genome and within horizontally transmissible DNA such as temperate bacteriophage. Previously, we showed that Rgg binds to the non-coding DNA upstream of the bacteriophage gene encoding an extracellular DNase Spd-3. In the current study, we further characterized Rgg-mediated regulation of spd-3 expression. Two spd-3 transcripts were identified by northern blotting. The 5? ends were 27 and 594 nucleotides upstream of the start codon as determined with primer extension analysis and 5? RACE (rapid amplification of c-DNA ends), respectively. Results obtained with gel shift assays showed that purified Rgg bound specifically to non-coding DNA containing the promoters of both transcripts. Transcriptional fusion analyses confirmed the presence of Rgg-repressible promoters within these DNA regions. In addition, repression was associated with direct DNA binding by Rgg as determined with chromatin immunoprecipitation (ChIP) coupled with quantitative PCR (qPCR). The results show that the chromosomally encoded transcriptional regulator, Rgg, directly represses both bacteriophage promoters controlling the expression of Spd-3. The results provide new information regarding the regulation of prophage encoded virulence factors of S. pyogenes and highlight the complex evolutionary history of S. pyogenes and temperate bacteriophage.
Anbalagan, Srivishnupriya; Chaussee, Michael S.
Streptococcus pyogenes is associated with a wide variety of mucosal and invasive infections that claim human life. The conversion from non pathogenic to toxigenic strain of S. pyogenes are thought to be mediated by bacteriophage infection in several cases. The hyaluronic acid (HA) degrading enzyme Hyaluronate lyase (HL) is proposed to be one of the key bacteriophage-encoded virulence factors. In the present work, HL of S. pyogenes bacteriophage H4489A (HylP) was expressed in Escherichia coli, purified and their structural and functional properties were studied. The enzyme exists in an extended trimeric conformation whose function is influenced by calcium ions. The collagenous Gly-X-Y motif of the enzyme influences stability and interact with calcium ions suggesting its role in the enzyme regulation The HylP shows sequential unfolding through the N-terminal domain. The primary catalytic residues of the enzyme seem to be in the first pocket consisting of Asp170 and Tyr182; however the enzyme activity is considerably reduced with mutation in the second pocket consisting of Glu295 and Tyr298. The catalytic residues span between the regions containing 135-308 amino acids where both the catalytic pocket has a prominent positively charged residue. The net positive potential of the cleft may help in recruiting the negatively charged polymeric HA. Interestingly, unlike other phage HLs, HylP is inhibited by l-ascorbic through non competitive manner. PMID:24721581
Singh, Sudhir Kumar; Malhotra, Soniya; Akhtar, Md Sohail
The Streptococcus pyogenes transcriptional regulator Rgg controls the expression of virulence-associated genes encoded both within the core genome and within horizontally transmissible DNA such as temperate bacteriophage. Previously, we showed that Rgg binds to the non-coding DNA upstream of the bacteriophage gene encoding an extracellular DNase Spd-3. In the current study, we further characterized Rgg-mediated regulation of spd-3 expression. Two spd-3 transcripts were identified by northern blotting. The 5' ends were 27 and 594 nucleotides upstream of the start codon as determined with primer extension analysis and 5' RACE (rapid amplification of c-DNA ends), respectively. Results obtained with gel shift assays showed that purified Rgg bound specifically to non-coding DNA containing the promoters of both transcripts. Transcriptional fusion analyses confirmed the presence of Rgg-repressible promoters within these DNA regions. In addition, repression was associated with direct DNA binding by Rgg as determined with chromatin immunoprecipitation (ChIP) coupled with quantitative PCR (qPCR). The results show that the chromosomally encoded transcriptional regulator, Rgg, directly represses both bacteriophage promoters controlling the expression of Spd-3. The results provide new information regarding the regulation of prophage encoded virulence factors of S. pyogenes and highlight the complex evolutionary history of S. pyogenes and temperate bacteriophage. PMID:23613830
Anbalagan, Srivishnupriya; Chaussee, Michael S
The pathogenic bacterium Group A Streptococcus pyogenes produces several extracellular DNases that have been shown to facilitate invasive infection by evading the human host immune system. DNases degrade the chromatin in neutrophil extracellular traps, enabling the bacterium to evade neutrophil capture. Spd1 is a type I, nonspecific ???/metal-dependent nuclease from Streptococcus pyogenes, which is encoded by the SF370.1 prophage and is likely to be expressed as a result of prophage induction. We present here the X-ray structure of this DNase in the wild-type and Asn145Ala mutant form. Through structural and sequence alignments as well as mutagenesis studies, we have identified the key residues His121, Asn145 and Glu164, which are crucial for Spd1 nucleolytic activity and shown the active site constellation. Our wild-type structure alludes to the possibility of a catalytically blocked dimeric form of the protein. We have investigated the multimeric nature of Spd1 using size-exclusion chromatography with multi-angle light scattering (SEC-MALLS) in the presence and absence of the divalent metal ion Mg2+, which suggests that Spd1 exists in a monomeric form in solution.
Korczynska, Justyna E.; Turkenburg, Johan P.; Taylor, Edward J.
Streptococcus pyogenes is a highly prevalent bacterial pathogen, most often giving rise to superficial infections at the throat or skin of its human host. Three genotype-defined subpopulations of strains exhibiting strong tropisms for either the throat or skin (specialists) or having no obvious tissue site preference (generalists) are recognized. Since the microenvironments at the throat and skin are distinct, the signal transduction pathways leading to the control of gene expression may also differ for throat versus skin strains of S. pyogenes. Two loci (mga and rofA/nra) encoding global regulators of virulence gene expression are positioned 300 kb apart on the genome; each contains alleles forming two major sequence clusters of approximately 25 to 30% divergence that are under balancing selection. Strong linkage disequilibrium is observed between sequence clusters of the transcription regulatory loci and the subpopulations of throat and skin specialists, against a background of high recombination rates among housekeeping genes. A taxonomically distinct commensal species (Streptococcus dysgalactiae subspecies equisimilus) shares highly homologous rof alleles. The findings provide strong support for a mechanism underlying niche specialization that involves orthologous replacement of regulatory genes following interspecies horizontal transfer, although the directionality of gene exchange remains unknown. PMID:15937178
Bessen, Debra E; Manoharan, Anand; Luo, Feng; Wertz, John E; Robinson, D Ashley
Streptococcus pyogenes is an important bacterial pathogen afflicting humans. A striking feature is its extraordinary biological diversity, evident in the wide range of diseases it can cause and the antigenic heterogeneity present on its surface. The T antigens form the basis of a major serological typing scheme that is often used as an alternative or supplement to M typing. Unlike M typing, the genetic basis for T typing is poorly understood. In this report, the tee6 gene is localized to a position approximately equal to 3.3 kb downstream from prtF1 (or sfbI), which encodes the Fn-binding protein, protein F, a key virulence factor. Comparison of this portion of the genome with those of four additional strains reveals the presence of genes encoding a collagen-binding protein (Cpa) and a second Fn-binding protein (PrtF2 or PfbpI). This chromosomal region--here designated the FCT region--is approximately 11 to 16 kb in length and is flanked at both ends by long stretches of highly conserved sequence. For each of the five strains, the FCT region contains a unique combination of semiconserved loci, indicative of extensive intergenomic recombination. The data provide evidence that the highly recombinatorial FCT region of the S. pyogenes genome is under strong selection for change in response to the host environment. PMID:11854196
Bessen, Debra E; Kalia, Awdhesh
The 1,815,783-bp genome of a serotype M49 strain of Streptococcus pyogenes (group A streptococcus [GAS]), strain NZ131, has been determined. This GAS strain (FCT type 3; emm pattern E), originally isolated from a case of acute post-streptococcal glomerulonephritis, is unusually competent for electrotransformation and has been used extensively as a model organism for both basic genetic and pathogenesis investigations. As with the previously sequenced S. pyogenes genomes, three unique prophages are a major source of genetic diversity. Two clustered regularly interspaced short palindromic repeat (CRISPR) regions were present in the genome, providing genetic information on previous prophage encounters. A unique cluster of genes was found in the pathogenicity island-like emm region that included a novel Nudix hydrolase, and, further, this cluster appears to be specific for serotype M49 and M82 strains. Nudix hydrolases eliminate potentially hazardous materials or prevent the unbalanced accumulation of normal metabolites; in bacteria, these enzymes may play a role in host cell invasion. Since M49 S. pyogenes strains have been known to be associated with skin infections, the Nudix hydrolase and its associated genes may have a role in facilitating survival in an environment that is more variable and unpredictable than the uniform warmth and moisture of the throat. The genome of NZ131 continues to shed light upon the evolutionary history of this human pathogen. Apparent horizontal transfer of genetic material has led to the existence of highly variable virulence-associated regions that are marked by multiple rearrangements and genetic diversification while other regions, even those associated with virulence, vary little between genomes. The genome regions that encode surface gene products that will interact with host targets or aid in immune avoidance are the ones that display the most sequence diversity. Thus, while natural selection favors stability in much of the genome, it favors diversity in these regions. PMID:18820018
McShan, W Michael; Ferretti, Joseph J; Karasawa, Tadahiro; Suvorov, Alexander N; Lin, Shaoping; Qin, Biafang; Jia, Honggui; Kenton, Steve; Najar, Fares; Wu, Hongmin; Scott, Julie; Roe, Bruce A; Savic, Dragutin J
Opsonization of bacteria by complement proteins is an important component of the immune response. The pathogenic bacterium Streptococcus pyogenes has evolved multiple mechanisms for the evasion of complement-mediated opsonization. One mechanism involves the binding of human regulators of complement activation such as factor H (FH) and FH-like protein 1 (FHL-1). Acquisition of these regulatory proteins can limit deposition of the opsonin C3b on bacteria, thus decreasing the pathogen's susceptibility to phagocytosis. Binding of complement regulatory proteins by S. pyogenes has previously been attributed to the streptococcal M and M-like proteins. Here, we report that the S. pyogenes cell surface protein Fba can mediate binding of FH and FHL-1. We constructed mutant derivatives of S. pyogenes that lack Fba, M1 protein, or both proteins and assayed the strains for FH binding, susceptibility to phagocytosis, and C3 deposition. Fba expression was found to be sufficient for binding of purified FH as well as for binding of FH and FHL-1 from human plasma. Plasma adsorption experiments also revealed that M1(+) Fba(+) streptococci preferentially bind FHL-1, whereas M1(-) Fba(+) streptococci have similar affinities for FH and FHL-1. Fba was found to contribute to the survival of streptococci incubated with human blood and to inhibit C3 deposition on bacterial cells. Streptococci harvested from log-phase cultures readily bound FH, but binding was greatly reduced for bacteria obtained from stationary-phase cultures. Bacteria cultured in the presence of the protease inhibitor E64 maintained FH binding activity in stationary phase, suggesting that Fba is removed from the cell surface via proteolysis. Western analyses confirmed that E64 stabilizes cell surface expression of Fba. These data indicate that Fba is an antiopsonic, antiphagocytic protein that may be regulated by cell surface proteolysis. PMID:12379699
Pandiripally, Vinod; Gregory, Eugene; Cue, David
The mechanisms that allow Streptococcus pyogenes to survive and persist in the human host, often in spite of antibiotic therapy, remain poorly characterized. Therefore, the determination of culture conditions for long-term studies is crucial to advancement in this field. Stationary cultures of S. pyogenes strain NZ131 and its spontaneous small-colony variant OK171 were found to survive in rich medium for less than 2 weeks, and this inability to survive resulted from the acidification of the medium to below pH 5.5, which the cells did not tolerate for longer than 6–7 days. The growth of NZ131 resulted in acidification of the culture to below pH 5.5 by the onset of stationary phase, and the loss of viability occurred in a linear fashion. These results were also found to be true for M49 strain CS101 and for M1 strain SF370. The S. pyogenes strains could be protected from killing by the addition of a buffer that stabilized the pH of the medium at pH 6.5, ensuring bacterial survival to at least 70 days. By contrast, increasing the glucose added to the medium accelerated the loss of culture viability in strain NZ131 but not OK171, suggesting that the small-colony variant is altered in glucose uptake or metabolism. Similarly, acidification of the medium prior to inoculation or at the middle of exponential phase resulted in growth inhibition of all strains. These results suggest that control of the pH is crucial for establishing long-term cultures of S. pyogenes.
McShan, William M.
The susceptibility of 40 erythromycin-resistant isolates of Streptococcus pyogenes and 40 multiply-resistant isolates of Streptococcus pneumoniae to six macrolide antibiotics, representing 14-, 15- and 16-membered lactone ring structures, was tested. The genetic basis for macrolide resistance in the strains was also determined. Both erm and mef determinants were encountered in the 36 S. pneumoniae isolates tested, but only mef in the five S. pyogenes isolates tested. All isolates showed cross-resistance among the 14-membered macrolides erythromycin, clarithromycin and roxithromycin and the 15-membered macrolide, azithromycin. However, the erythromycin-resistant S. pyogenes isolates retained full susceptibility to spiramycin and josamycin (16-membered agents). These latter two antibiotics were also more active than the other macrolides against erythromycin-resistant S. pneumoniae isolates, especially josamycin which was 8-64 times more active than erythromycin; spiramycin was only two to eight times more active than erythromycin. PMID:10052895
Klugman, K P; Capper, T; Widdowson, C A; Koornhof, H J; Moser, W
A scarlet fever outbreak caused by Streptococcus pyogenes occurred in China in 2011. To determine the genomic features of the outbreak strains, we deciphered genomes of two strains isolated from the regions with the highest incidence rates. The sequences will provide valuable information for comprehensive study of mechanisms related to this outbreak.
You, Yuanhai; Yang, Xianwei; Song, Yanyan; Yan, Xiaomei; Yuan, Yanting; Li, Dongfang; Yan, Yanfeng; Wang, Haibin; Tao, Xiaoxia; Li, Leilei; Jiang, Xihong; Zhou, Hao; Xiao, Di; Jin, Lianmei; Feng, Zijian; Yang, Ruifu; Luo, Fengji
We studied the binding of cells of Streptococcus pyogenes and mannose-sensitive Escherichia coli to human fibroblast cell lines and isolated buccal epithelial cells in relation to the cell-associated endogenous or exogenous fibronectin of the host cells. The degree of bacterial binding to cell lines correlated directly with the content of endogenous fibronectin on the surface of the cultured cells, although the correlation was better with S. pyogenes than with E. coli. The addition of exogenous plasma fibronectin to the cell lines or oral epithelial cells enhanced binding of S. pyogenes but suppressed binding of mannose-sensitive E. coli. These findings are consistent with the notion that exogenously acquired fibronectin on the surface of host cells modulates bacterial adherence by providing attachment sites for certain pathogens, such as S. pyogenes, and by blocking receptors for others, such as mannose-sensitive E. coli.
Stanislawski, L; Simpson, W A; Hasty, D; Sharon, N; Beachey, E H; Ofek, I
SpyCEP is a Streptococcus pyogenes protease that cleaves CXCL8/IL-8 and its activity is associated with human invasive disease severity. We investigated the role of SpyCEP in S. pyogenes necrotizing fasciitis and respiratory tract infection in mice using isogenic strains differing only in SpyCEP expression. SpyCEP cleaved human CXCL1, 2, 6 and 8 plus murine CXCL1 and 2 at a structurally conserved site. Mice were infected in thigh muscle with a strain of S. pyogenes that expresses a high level of SpyCEP, or with an isogenic non-SpyCEP expressing strain. SpyCEP expression by S. pyogenes hindered bacterial clearance from muscle, and enhanced bacterial spread, associated with cleavage of murine chemoattractant CXCL1. Mice were then infected with Lactococcus lactis strains that differed only in SpyCEP expression. In contrast to the parent L. lactis strain (lacks SpyCEP), which was avirulent when administered intramuscularly, infection with a strain that expressed SpyCEP heterologously led to dramatic systemic illness within 24 h, failure to clear bacteria from muscle and marked dissemination to other organs. In the upper airways, SpyCEP expression was required for survival of L. lactis but not S. pyogenes. However, dissemination of S. pyogenes to the lung was SpyCEP-dependent and was associated with evidence of chemokine cleavage. Taken together, the studies provide clear evidence that SpyCEP is necessary and sufficient for systemic bacterial dissemination from a soft tissue focus in this model and also underlies dissemination in the respiratory tract. PMID:20158613
Kurupati, Prathiba; Turner, Claire E; Tziona, Ioanna; Lawrenson, Richard A; Alam, Faraz M; Nohadani, Mahrokh; Stamp, Gordon W; Zinkernagel, Annelies S; Nizet, Victor; Edwards, Robert J; Sriskandan, Shiranee
Objective To determine the incidence of carrier state of Haemophilus influenzae type b, Streptococcus pneumoniae (S. pneumoniae), Streptococcus pyogenes, Neisseria meningitidis and Corynebacterium diphtheriae among school children. Methods Specimen from posterior pharyngeal wall and tonsils were collected on calcium alginate coated swabs from 102 participants. Processing of specimen and antimicrobial susceptibility testing was done by standard procedures. Results Potential pathogens isolated in our study were S. pneumoniae (14.7%), Staphylococcus aureus (12.7%), Corynebacterium diphtheriae (3.9%), Streptococcus pyogenes (3.9%) and Haemophilus influenzae (1.9%). Important findings in antibiogram include high resistance of S. pneumoniae to penicillin (73%) and resistance of Staphylococcus aureus to oxacillin (23%). Conclusions Pharyngeal colonization by S. pneumoniae among school children was found high and there is need of introduction of pneumococcal vaccines among children. Despite expected universal vaccination, pharyngeal colonization by Corynebacterium diphtheriae is possible and there is possibility of transmission.
Bhatta, Dharm Raj; Gokhale, Shishir; Sharma, Annavarapu Laxminarasimha; Gupta, Umesh; Gaur, Abhishek; Gowda, Supram; Raut, Shristi; Thapa, Sangeeta; Khadka, Rupendra
Streptococcus pyogenes is a leading cause of pharyngeal infection, with an estimated 616 million cases per year. The human nasopharynx represents the major reservoir for all S. pyogenes infection, including severe invasive disease. To investigate bacterial and host factors that influence S. pyogenes infection, we have devised an improved murine model of nasopharyngeal colonization, with an optimized dosing volume to avoid fulminant infections and a sensitive host strain. In addition we have utilized a refined technique for longitudinal monitoring of bacterial burden that is non-invasive thereby reducing the numbers of animals required. The model was used to demonstrate that the two component regulatory system, CovR/S, is required for optimum infection and transmission from the nasopharynx. There is a fitness cost conferred by covR/S mutation that is specific to the nasopharynx. This may explain why S. pyogenes with altered covR/S have not become prevalent in community infections despite possessing a selective advantage in invasive infection.
Alam, Faraz M.; Turner, Claire E.; Smith, Ken; Wiles, Siouxsie; Sriskandan, Shiranee
Background Streptococcal toxic shock syndrome (STSS) is an uncommon but life-threatening disease caused by Streptococcus pyogenes. Methods To understand the clinical and molecular characteristics of STSS, we analyzed clinical data and explored the emm types, superantigen genes, and pulsed-field gel electrophoresis of causative S. pyogenes isolates obtained between 2005 and 2012. Results In total, 53 patients with STSS were included in this study. The median age of the patients was 57 years (range: 9–83 years), and 81.1% were male. The most prevalent underlying disease was diabetes mellitus (45.3%). Skin and soft-tissue infection accounted for 86.8% of STSS. The overall mortality rate was 32.1%. Underlying diseases had no statistical impact on mortality. A total of 19 different emm types were identified. The most prevalent emm type was emm102 (18.9%), followed by emm11 (17%), emm1 (11.3%), emm87 (9.4%), and emm89 (7.5%). There was no statistically significant association between emm type and a fatal outcome. Among the superantigen genes, speB was the most frequently detected one (92.5%), followed by smeZ (90.6%), speG (81.1%), speC (39.6%), and speF (39.6%). The majority of emm102 strains were found to have speB, speC, speG, and smeZ. The presence of speG was negatively associated with a fatal outcome (P?=?0.045). Conclusions Our surveillance revealed the emergence of uncommon emm types, particularly emm102, causing STSS in southern Taiwan. Characterization of clinical, epidemiological, and molecular characteristics of STSS will improve our understanding of this life-threatening disease.
Lin, Jiun-Nong; Chang, Lin-Li; Lai, Chung-Hsu; Lin, Hsi-Hsun; Chen, Yen-Hsu
Streptococcus pyogenes is the most common bacterial pathogen causing pharyngotonsillitis, and also can lead to diseases such as otitis media, impetigo, necrotizing fasciitis, bacteremia, sepsis and toxic shock-like syndrome. M protein encoded by emm gene is an important virulence factor of S.pyogenes and it is used for genotyping in epidemiological studies. The aims of this study were to determine the M protein types of group A streptococci (GAS) by using emm gene sequence analysis method, to compare the M types in terms of analogy with the vaccine in development and to determine the antibiotic susceptibilities of the isolates. A total of 35 GAS strains isolated from various clinical specimens in our laboratory were included in the study. Strains growing in blood culture were considered as invasive, strains growing in throat and abscess cultures were considered as non-invasive. The isolates have been identified by conventional methods and 16S rRNA sequence analysis at species level. emm genotyping of strains identified as S.pyogenes, was performed by PCR method as proposed by the CDC. Amplicons were obtained and sequenced in 23 out of 35 isolates. The results were compared with CDC emm sequence database. Antibiotic susceptibility of the isolates was performed by agar dilution method and evaluated as recommended by CLSI. Twenty-three out of 35 isolates could be typed and 15 different emm genotypes were detected. The most common emm types were emm1 (22%), emm89 (13%), emm18 (9%) and emm19 (9%). The detection rate of other emm types (emm5, 12, 14, 17, 26, 29, 37, 74, 78, 92, 99) was 47%. Types emm1, 12, 19, 74, 89 and 99 were observed in strains isolated from blood cultures. It was detected that nine of the 15 (60%) emm types are within the contents of 26 valent vaccine (emm 1, 5, 12, 14, 18, 19, 29, 89, 92). It was also observed that 17 (74%) of the 23 cases were infected by vaccine types and the four emm types (emm1, 12, 19, 89) identified in blood samples were among the vaccine types. All of the strains were found susceptible to penicillin, ampicillin, erythromycin, lincomycin, gentamicin, chloramphenicol, vancomycin and linezolid, however six isolates were resistant to levofloxacin (MIC= 4 and 16 µg/ml) and one isolate was resistant to tetracycline (MIC= 16 µg/ml). In conclusion, this preliminary local study with limited number of invasive and non-invasive S.pyogenes isolates, emphasized the need for larger scale multi-center studies to determine the analogy and efficacy of the vaccine in development. PMID:23621731
Arslan, U?ur; Orya??n, Erman; Eskin, Zeynep; Türk Da??, Hatice; F?nd?k, Duygu; Tuncer, Inci; Bozdo?an, Bülent
We studied the uptake of ..cap alpha..-aminoisobutyric acid (AIB) in Streptococcus pyogenes and its physiologically isotonic L-form. S. pyogenes cells starved for glucose or treated with carbonyl cyanide-m-chlorophenyl hydrazone accumulated limited amounts of AIB. A high apparent K/sub m/ value characterized the glucose-independent transport of AIB. The rate and extent of AIB accumulation significantly increased in the presence of glucose. Two saturable transport components with distinct apparent K/sub m/values characterized glycolysis-coupled transport of AIB. A biphasic Lineweaver-Burk plot was also obtained for L-alanine transport by glycolyzing S. pyogenes cells. AIB seems to share a common transport system(s) with glycine, L- and D-anine, L-serine, and L-valine. This was shown by the competitive exchange efflux of accumulated AIB. About 30% of the AIB uptake was not inhibited by a saturating amount of L-valine, indicating the existence of more than one system for AIB transport, p-Chloromercuribenzoate markedly inhibited the accumulation of AIB by both glycolyzing and glucose-starved cells. In contrast, carbonyl cyanide-m-chlorophenyl hydrazone affected only metabolism-dependent uptake of AIB, which was also sensitive to dinitrophenol, N-ethylmaleimide, iodoacetate, fluoride (NaF), arsenate, and N,N'-dicyclohexylcarbodiimide. These results are interpreted according to the chemiosmotic theory of Mitchell, whereby a proton motive force constitutes the driving force for AIB accumulation. AIB was not accumulated by the L-form. However, a temporary accumulation of AIB by a counterflow mechanism and a saturable system with a low apparent affinity were demonstrated for AIB transport by this organism. We suggest that a deficiency in the coupling of energy to AIB transport is responsible for the apparent lack of active AIB accumulation by the L-form.
Reizer, J.; Panos, C.
M protein gene typing was used to analyse Streptococcus pyogenes clinical isolates collected between 1983 and 1995 in an area of central Italy from patients presenting different types of infections; the same isolates were also characterized by means of DNA fingerprinting. M type 1 was the most common (50% of study strains), followed by M types 4, 12 and 6. The proportion of M type 12 decreased with time, whereas M type 1 increased, in agreement with data obtained in many different areas. Most invasive strains belonged to types M1 (30%) and M12 (30%); on the other hand, the M1 type did frequently occur also among non-invasive isolates. DNA fingerprinting showed a correlation between M types and DNA patterns. This report provides epidemiological information from a geographic area not sampled recently, and further shows the usefulness of the M genotyping technique, which offers potential advantages over conventional serological typing methods.
Mencarelli, M.; Corbisiero, R.; Marzocchi, B.; Gistri, A.; Signori, R.; Rossolini, A.; Cellesi, C.
The presence of antigens in heart muscles cross-reactive with antibodies against Streptococcus pyogenes were examined in heart samples of seven primate species (chimpanzee, rhesus macaque, stump-tailed macaque, hamadryas baboon, capuchin monkey, green monkey and patas monkey). Cross-reactive antigens were localized by means of the indirect immunofluorescent technique in nearly all samples tested. The fluorescence pattern was the same as found in the heart muscle of other mammals. Using the indirect immunoferritin technique the substructural distribution of the antigens was investigated in heart muscle of rhesus macaque and hamadryas baboon. Beside the location on the cell surface the antigens were also demonstrated within the cell. Above all there was a strong labelling along the intercalated discs and in the sarcoplasmatic reticulum. PMID:116866
Wagner, M; Wagner, B; Dhikidze, E K
Background The enzymatic hydrolysis of ??mannosides is catalyzed by glycoside hydrolases (GH), termed ??mannosidases. These enzymes are found in different GH sequence–based families. Considerable research has probed the role of higher eukaryotic “GH38” ??mannosides that play a key role in the modification and diversification of hybrid N-glycans; processes with strong cellular links to cancer and autoimmune disease. The most extensively studied of these enzymes is the Drosophila GH38 ??mannosidase II, which has been shown to be a retaining ??mannosidase that targets both ??1,3 and ??1,6 mannosyl linkages, an activity that enables the enzyme to process GlcNAc(Man)5(GlcNAc)2 hybrid N-glycans to GlcNAc(Man)3(GlcNAc)2. Far less well understood is the observation that many bacterial species, predominantly but not exclusively pathogens and symbionts, also possess putative GH38 ??mannosidases whose activity and specificity is unknown. Methodology/Principal Findings Here we show that the Streptococcus pyogenes (M1 GAS SF370) GH38 enzyme (Spy1604; hereafter SpGH38) is an ??mannosidase with specificity for ??1,3 mannosidic linkages. The 3D X-ray structure of SpGH38, obtained in native form at 1.9 Å resolution and in complex with the inhibitor swainsonine (Ki 18 µM) at 2.6 Å, reveals a canonical GH38 five-domain structure in which the catalytic “–1” subsite shows high similarity with the Drosophila enzyme, including the catalytic Zn2+ ion. In contrast, the “leaving group” subsites of SpGH38 display considerable differences to the higher eukaryotic GH38s; features that contribute to their apparent specificity. Conclusions/Significance Although the in vivo function of this streptococcal GH38 ??mannosidase remains unknown, it is shown to be an ??mannosidase active on N-glycans. SpGH38 lies on an operon that also contains the GH84 hexosaminidase (Spy1600) and an additional putative glycosidase. The activity of SpGH38, together with its genomic context, strongly hints at a function in the degradation of host N- or possibly O-glycans. The absence of any classical signal peptide further suggests that SpGH38 may be intracellular, perhaps functioning in the subsequent degradation of extracellular host glycans following their initial digestion by secreted glycosidases.
Suits, Michael D. L.; Zhu, Yanping; Taylor, Edward J.; Walton, Julia; Zechel, David L.; Gilbert, Harry J.; Davies, Gideon J.
A number of bacterial collagen-like proteins with Gly as every third residue and a high Pro content have been observed to form stable triple-helical structures despite the absence of hydroxyproline (Hyp). Here, the high yield cold-shock expression system is used to obtain purified recombinant collagen-like protein (V-CL) from Streptococcus pyogenes containing an N-terminal globular domain V followed by the collagen triple-helix domain CL and the modified construct with two tandem collagen domains V-CL-CL. Both constructs and their isolated collagenous domains form stable triple-helices characterized by very sharp thermal transitions at 35–37°C and by high values of calorimetric enthalpy. Procedures for the formation of collagen SLS crystallites lead to parallel arrays of in register V-CL-CL molecules, as well as centrosymmetric arrays of dimers joined at their globular domains. At neutral pH and high concentrations, the bacterial constructs all show a tendency towards aggregation. The isolated collagen domains, CL and CL-CL, form units of diameter 4–5 nm which bundle together and twist to make larger fibrillar structures. Thus, although this S. pyogenes collagen-like protein is a cell surface protein with no indication of participation in higher order structure, the triple-helix domain has the potential of forming fibrillar structures even in the absence of hydroxyproline. The formation of fibrils suggests bacterial collagen proteins may be useful for biomaterials and tissue engineering applications.
Yoshizumi, Ayumi; Yu, Zhuoxin; Silva, Teresita; Thiagarajan, Geetha; Ramshaw, John A M; Inouye, Masayori; Brodsky, Barbara
Streptococcus pyogenes (group A streptococcus [GAS]) responds to environmental changes in a manner that results in an adaptive regulation of the transcriptome. The objective of the present study was to understand how two global transcriptional regulators, CodY and CovRS, coordinate the transcriptional network in S. pyogenes. Results from expression microarray data and quantitative reverse transcription-PCR (qRT-PCR) showed that the global regulator CodY controls the expression of about 250 genes, or about 17% of the genome of strain NZ131. Additionally, the codY gene was shown to be negatively autoregulated, with its protein binding directly to the promoter region with a CodY binding site. In further studies, the influence of codY, covRS, and codY-covRS mutations on gene expression was analyzed in growth phase-dependent conditions using C medium, reported to mimic nutritional abundance and famine conditions similar to those found during host GAS infection. Additional biological experiments of several virulence phenotypes, including pilin production, biofilm formation, and NAD glycohydrolase activity, demonstrated the role that both CodY and CovRS play in their regulation. Correlation analysis of the overall data revealed that, in exponentially growing cells, CodY and CovRS act in opposite directions, with CodY stimulating and CovRS repressing a substantial fraction of the core genome, including many virulence factors. This is the first report of counteractive balancing of transcriptome expression by global transcription regulators and provides important insight into how GAS modulates gene expression by integrating important extracellular and intracellular information.
Kreth, Jens; Chen, Zhiyun; Ferretti, Joseph; Malke, Horst
Streptococcus pyogenes is a notorious pathogenic bacterium which causes various human diseases ranging from localized infections to life threatening invasive diseases. Streptolysin-O (SLO), pore-forming thiol-activated cytolysin, is the major virulent factor for streptococcal infections. Present therapies against streptococcal infections are limited as most of the strains have developed multi-drug resistance to present generation of drugs. Hence, there is a need for alternative therapeutic substances. Structure based virtual screening is a novel platform to select lead molecules with better pharmacokinetic properties. The 3D structure of SLO (not available in native form), essential for such studies, was computationally generated and this homology model was used as probable drug target. Based on literature survey, several phytoligands from 25 medicinal plants were selected. Out of these, leads from 11 plants showed better pharmacokinetic properties. The best lead molecules were screened based on computer aided drug likeness and pharmacokinetic predictions. The inhibitory properties of selected herbal leads against SLO were studied by molecular docking. An in vitro assay was further carried out and variations observed were found to be significant (p<0.05). Antibiotic sensitivity testing was also performed with the clinical strain of Streptococcus pyogenes with conventional drugs. The clinical strain showed multi-drug resistance to conventional drugs. Our study revealed that numerous phytoligands have better inhibitory properties towards the toxin. We noticed that incorporation of selected herbal extracts in blood agar medium showed significant reduction in hemolysis (MIC 300?l/plate), indicating inhibition of SLO. Furthermore, the butanol extracts of selected herbal preparation based on computer aided screening showed significant inhibitory properties at 250 mcg/disc concentration. We also noticed that selected herbal formulations have better antimicrobial properties at MIC range of 300- 400?l. Hence, our study suggests that these herbal extracts have better inhibitory properties against the toxin as well as drug resistant Streptococcus pyogenes. PMID:24694051
Skariyachan, Sinosh; Narayan, Naik Sowmyalaxmi; Aggimath, Tejaswini S; Nagaraj, Sushmitha; Reddy, Monika S; Narayanappa, Rajeswari
The important human pathogen Streptococcus pyogenes (group A streptococcus, GAS) initiates infection by pilus-mediated attachment to host tissue. Thus, the pilus is an excellent target for design of anti-infective strategies. The T3 pilus of GAS is composed of multiple covalently linked subunits of the T3 protein to which the two minor pilins, Cpa and OrfB, are covalently attached. Because the proteins of GAS pili do not contain either of the motifs required for pilus polymerization in other Gram-positive bacteria, we investigated the residues involved in their linkage. We show that linkage of Cpa to T3 by the sortase family transpeptidase SrtC2 requires the VPPTG motif in the cell wall-sorting signal of Cpa. We also demonstrate that K173 of T3 is required both for T3 polymerization and for attachment of Cpa to T3. Therefore, attachment of Cpa to K173 of a T3 subunit would block further addition of T3 subunits to this end of the growing pilus. This implies that Cpa is located exclusively at the pilus tip, a location supported by immunogold electron microscopy, and suggests that, as for well-studied pili on Gram-negative bacteria, the role of the pilus is to present the adhesin external to the bacterial capsule. PMID:19432798
Quigley, Bernard R; Zähner, Dorothea; Hatkoff, Matthew; Thanassi, David G; Scott, June R
The group A streptococcus (GAS) Streptococcus pyogenes is known to cause self-limiting purulent infections in humans. The role of GAS pili in host cell adhesion and biofilm formation is likely fundamental in early colonization. Pilus genes are found in the FCT (fibronectin-binding protein, collagen-binding protein, and trypsin-resistant antigen) genomic region, which has been classified into nine subtypes based on the diversity of gene content and nucleotide sequence. Several epidemiological studies have indicated that FCT type 1 strains, including serotype M6, produce large amounts of monospecies biofilm in vitro. We examined the direct involvement of pili in biofilm formation by serotype M6 clinical isolates. In the majority of tested strains, deletion of the tee6 gene encoding pilus shaft protein T6 compromised the ability to form biofilm on an abiotic surface. Deletion of the fctX and srtB genes, which encode pilus ancillary protein and class C pilus-associated sortase, respectively, also decreased biofilm formation by a representative strain. Unexpectedly, these mutant strains showed increased bacterial aggregation compared with that of the wild-type strain. When the entire FCT type 1 pilus region was ectopically expressed in serotype M1 strain SF370, biofilm formation was promoted and autoaggregation was inhibited. These findings indicate that assembled FCT type 1 pili contribute to biofilm formation and also function as attenuators of bacterial aggregation. Taken together, our results show the potential role of FCT type 1 pili in the pathogenesis of GAS infections.
Kimura, Keiji Richard; Nakata, Masanobu; Sumitomo, Tomoko; Kreikemeyer, Bernd; Podbielski, Andreas; Terao, Yutaka
The macrolide efflux gene mef(A) of the Streptococcus pyogenes clinical strain 2812A was found to be carried by a 52-kb chromosomal genetic element that could be transferred by conjugation to the chromosome of other streptococcal species. The characteristics of this genetic element are typical of conjugative transposons and was named Tn1207.3. The size of Tn1207.3 was established by pulsed-field gel electrophoresis (PFGE), and DNA sequencing analysis showed that the 7,244 bp at the left end of Tn1207.3 were identical to those of the pneumococcal Tn1207.1 element. Tn1207.3-like genetic elements were found to be inserted at a single specific chromosomal site in 12 different clinical isolates S. pyogenes exhibiting the M phenotype of resistance to macrolides and carrying the mef(A) gene. Tn1207.3 was transferred from S. pyogenes 2812A to Streptococcus pneumoniae, and sequence analysis carried out on six independent transconjugants showed that insertion of Tn1207.3 in the pneumococcal genome always occurred at a single specific site as in Tn1207.1. Using MF2, a representative S. pneumoniae transconjugant, as a donor, Tn1207.3 was transferred again by conjugation to S. pyogenes and Streptococcus gordonii. The previously described nonconjugative element Tn1207.1 of S. pneumoniae appears to be a defective element, part of a longer conjugative transposon that carries mef(A) and is found in clinical isolates of S. pyogenes. PMID:12959402
Santagati, Maria; Iannelli, Francesco; Cascone, Carmela; Campanile, Floriana; Oggioni, Marco R; Stefani, Stefania; Pozzi, Gianni
Streptococcus pyogenes strains can be divided into two classes, one capable and the other incapable of producing H2O2 (M. Saito, S. Ohga, M. Endoh, H. Nakayama, Y. Mizunoe, T. Hara, and S. Yoshida, Micro- biology 147:2469-2477, 2001). In the present study, this dichotomy was shown to parallel the presence or absence of H2O2-producing lactate oxidase activity in permeabilized cells. Both
Masanori Seki; Ken-ichiro Iida; Mitsumasa Saito; Hiroaki Nakayama; Shin-ichi Yoshida
Streptococcus pyogenes isolates obtained in 1981 to 1997 from patients and healthy subjects were character- ized by pulsed-field gel electrophoresis (PFGE) patterns, biotyping, and the presence of spe genes encoding streptococcal pyrogenic exotoxins. Changes in the profiles were shown in the serotype M1\\/T1 isolates from pharyngitis over this period, but not in serotype M3\\/T3 isolates. The characteristics of isolates from
TOSHIYUKI MURASE; RIEKO SUZUKI; RO OSAWA; SHIRO YAMAI
A survey of emm gene sequences and an analysis of the pulsed-field electrophoretic profiles of 30 Streptococcus pyogenes isolates with reduced susceptibilities to ciprofloxacin detected the prevalence of isolates with emm type 6 and considerable genetic diversity among isolates. The mechanism of ciprofloxacin resistance in these isolates was based on point mutations in topoisomerase IV subunit C encoded by parC, mainly replacement of serine-79 by alanine.
Alberti, Sebastian; Cortes, Guadalupe; Garcia-Rey, Cesar; Rubio, Carmen; Baquero, Fernando; Garcia-Rodriguez, Jose Angel; Bouza, Emilio; Aguilar, Lorenzo
Macrophages are phagocytes that recognize bacteria and subsequently activate appropriate innate and adaptive immune responses. TLRs are essential in identifying conserved bacterial structures and in initiating and mediating innate immune responses. In this work, we have characterized TLR gene expression in human monocyte-derived macrophages in response to stimulation with two live Gram-positive bacteria, a human commensal and probiotic Lactobacillus rhamnosus GG (LGG), and an important human pathogen Streptococcus pyogenes. LGG and S. pyogenes enhanced TLR2 expression in macrophages. LGG and S. pyogenes also required TLR2 for NF-kappaB activation. Only pathogenic S. pyogenes was able to up-regulate TLR3 and TLR7 gene expression. This up-regulation was dependent on IFN-alpha/beta, as neutralizing anti-IFN-alpha/beta antibodies reduced S. pyogenes-induced TLR3 and TLR7 mRNA expression. Our results show that despite similarities, TLR responses of macrophages differ for a Gram-positive probiotic and a pathogen. Our data suggest that macrophages can discriminate between probiotic and pathogenic bacteria by IFN-mediated TLR gene regulation. PMID:18625909
Miettinen, Minja; Veckman, Ville; Latvala, Sinikka; Sareneva, Timo; Matikainen, Sampsa; Julkunen, Ilkka
Changes in the structural components of the Streptococcus pyogenes membrane between exponential and early stationary phases of growth are reported. The overall protein composition ranged from 70 to 73% of the dry weight of the membranes, irrespective of the phase of growth from which they were isolated. Amino acid analyses of membranes isolated from streptococci in either the exponential or stationary phase of growth demonstrated that two amino acids, cysteine and tryptophan, were absent. Further analysis of the membrane proteins by sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis demonstrated that there were proteins unique to a particular phase of growth as well as differences in the amount of specific proteins from the various growth phases. In addition, membranes isolated from exponential-phase cultures contained a higher percentage of peripheral protein than did stationary-phase membranes. There also appeared to be an increase in the amount of outer surface proteins during this growth phase. The phosphorus content of the membranes increased during the stationary phase of growth, whereas the sugar composition remained constant. The only sugar found under various conditions of growth in any of the strains was glucose. Total fatty acid content and the mole percent composition of various fatty acids did not change in the different phases of growth. However, the mole percent composition of fatty acids in the membranes of various group A streptococci did differ between strains. Therefore, these results provide evidence that the composition of membranes of S. pyogenes does not remain constant throughout the growth phases of the culture. Images
van de Rijn, Ivo; Kessler, Robert E.
A number of bacterial collagen-like proteins with Gly as every third residue and a high Pro content have been observed to form stable triple-helical structures despite the absence of hydroxyproline (Hyp). Here, the high yield cold-shock expression system is used to obtain purified recombinant collagen-like protein (V-CL) from Streptococcus pyogenes containing an N-terminal globular domain V followed by the collagen triple-helix domain CL and the modified construct with two tandem collagen domains V-CL-CL. Both constructs and their isolated collagenous domains form stable triple-helices characterized by very sharp thermal transitions at 35-37 degrees C and by high values of calorimetric enthalpy. Procedures for the formation of collagen SLS crystallites lead to parallel arrays of in register V-CL-CL molecules, as well as centrosymmetric arrays of dimers joined at their globular domains. At neutral pH and high concentrations, the bacterial constructs all show a tendency towards aggregation. The isolated collagen domains, CL and CL-CL, form units of diameter 4-5 nm which bundle together and twist to make larger fibrillar structures. Thus, although this S. pyogenes collagen-like protein is a cell surface protein with no indication of participation in higher order structure, the triple-helix domain has the potential of forming fibrillar structures even in the absence of hydroxyproline. The formation of fibrils suggests bacterial collagen proteins may be useful for biomaterials and tissue engineering applications. PMID:19472339
Yoshizumi, Ayumi; Yu, Zhuoxin; Silva, Teresita; Thiagarajan, Geetha; Ramshaw, John A M; Inouye, Masayori; Brodsky, Barbara
ABSTRACT Recent studies have established the fact that multiple members of the Rgg family of transcriptional regulators serve as key components of quorum sensing (QS) pathways that utilize peptides as intercellular signaling molecules. We previously described a novel QS system in Streptococcus pyogenes which utilizes two Rgg-family regulators (Rgg2 and Rgg3) that respond to neighboring signaling peptides (SHP2 and SHP3) to control gene expression and biofilm formation. We have shown that Rgg2 is a transcriptional activator of target genes, whereas Rgg3 represses expression of these genes, and that SHPs function to activate the QS system. The mechanisms by which Rgg proteins regulate both QS-dependent and QS-independent processes remain poorly defined; thus, we sought to further elucidate how Rgg2 and Rgg3 mediate gene regulation. Here we provide evidence that S. pyogenes employs a unique mechanism of direct competition between the antagonistic, peptide-responsive proteins Rgg2 and Rgg3 for binding at target promoters. The highly conserved, shared binding sites for Rgg2 and Rgg3 are located proximal to the ?35 nucleotide in the target promoters, and the direct competition between the two regulators results in concentration-dependent, exclusive occupation of the target promoters that can be skewed in favor of Rgg2 in vitro by the presence of SHP. These results suggest that exclusionary binding of target promoters by Rgg3 may prevent Rgg2 binding under SHP-limiting conditions, thereby preventing premature induction of the quorum sensing circuit.
LaSarre, Breah; Aggarwal, Chaitanya; Federle, Michael J.
The Streptococcus pyogenes NAD+ glycohydrolase (SPN) is secreted from the bacterial cell and translocated into the host cell cytosol where it contributes to cell death. Recent studies suggest that SPN is evolving and has diverged into NAD+ glycohydrolase-inactive variants that correlate with tissue tropism. However, the role of SPN in both cytotoxicity and niche selection are unknown. To gain insight into the forces driving the adaptation of SPN, a detailed comparison of representative glycohydrolase activity-proficient and -deficient variants was conducted. Of a total 454 amino acids, the activity-deficient variants differed at only nine highly conserved positions. Exchanging residues between variants revealed that no one single residue could account for the inability of the deficient variants to cleave the glycosidic bond of ?-NAD+ into nicotinamide and ADP-ribose; rather, reciprocal changes at 3 specific residues were required to both abolish activity of the proficient version and restore full activity to the deficient variant. Changing any combination of 1 or 2 residues resulted in intermediate activity. However, a change to any 1 residue resulted in a significant decrease in enzyme efficiency. A similar pattern involving multiple residues was observed for comparison with a second highly conserved activity-deficient variant class. Remarkably, despite differences in glycohydrolase activity, all versions of SPN were equally cytotoxic to cultured epithelial cells. These data indicate that the glycohydrolase activity of SPN may not be the only contribution the toxin has to the pathogenesis of S. pyogenes and that both versions of SPN play an important role during infection.
Chandrasekaran, Sukantha; Ghosh, Joydeep; Port, Gary C.; Koh, Eun-ik; Caparon, Michael G.
The CovR/S system in Streptococcus pyogenes (Group A Streptococcus, or GAS), a two-component signal transduction/transcription regulation system, controls the expression of major virulence factors. The presence of a negative feedback loop distinguishes the CovR/S system from the majority of bacterial two-component systems. We developed a deterministic model of the CovR/S system consisting of eight delay differential equations. Computational experiments showed that the system possessed a unique stable steady state. The dynamical behavior of the system showed a tendency for oscillations becoming more pronounced for longer but still biochemically realistic delays related to reductions in the rates of transcription and translation elongation. We have devised an efficient procedure for computing the system’s steady-state. Further, we have shown that the signal–response curves are hyperbolic for the default parameter values. However, in experiments with randomized parameters we demonstrated that sigmoidality of signal–response curves, implying a response threshold, is not only possible, but seems to be rather typical for CovR/S-like systems even when binding of the CovR response regulator protein to a promoter is non-cooperative. We used sensitivity analysis to simplify the model in order to make it analytically tractable. The existence and uniqueness of the steady state and hyperbolicity of signal–response curves was proved for the simplified model. Also, we found that provided CovS was active, the system was insensitive to changes in the concentration of any other phosphoryl donor such as acetyl phosphate.
Mitrophanov, Alexander Y.; Churchward, Gordon; Borodovsky, Mark
Staphylococcus aureus and Streptococcus pyogenes secrete exotoxins that act as superantigens, proteins that cause hyperimmune reactions by binding the variable domain of the T-cell receptor beta chain (V?), leading to stimulation of a large fraction of the T-cell repertoire. To develop potential neutralizing agents, we engineered V? mutants with high affinity for the superantigens staphylococcal enterotoxin B (SEB), SEC3, and streptococcal pyrogenic exotoxin A (SpeA). Unexpectedly, the high-affinity V? mutants generated against SEB cross-reacted with SpeA to a greater extent than they did with SEC3, despite greater sequence similarity between SEB and SEC3. Likewise, the V? mutants generated against SpeA cross-reacted with SEB to a greater extent than with SEC3. The structural basis of the high affinity and cross-reactivity was examined by single-site mutational analyses. The cross-reactivity seems to involve only one or two toxin residues. Soluble forms of the cross-reactive V? regions neutralized both SEB and SpeA in vivo, suggesting structure-based strategies for generating high-affinity neutralizing agents that can cross-react with multiple exotoxins.
Wang, Ningyan; Mattis, Daiva M.; Sundberg, Eric J.; Schlievert, Patrick M.; Kranz, David M.
Uridine phosphorylase (UP), a key enzyme in the pyrimidine salvage pathway, catalyzes the reversible phosphorolysis of uridine or 2?-deoxyuridine to uracil and ribose 1-phosphate or 2?-deoxyribose 1-phosphate. This enzyme belongs to the nucleoside phosphorylase I superfamily whose members show diverse specificity for nucleoside substrates. Phylogenetic analysis shows Streptococcus pyogenes uridine phosphorylase (SpUP) is found in a distinct branch of the pyrimidine subfamily of nucleoside phosphorylases. To further characterize SpUP, we determined the crystal structure in complex with the products, ribose 1-phosphate and uracil, at 1.8 Å resolution. Like Escherichia coli UP (EcUP), the biological unit of SpUP is a hexamer with an ?/? monomeric fold. A novel feature of the active site is the presence of His169, which structurally aligns with Arg168 of the EcUP structure. A second active site residue, Lys162, is not present in previously determined UP structures and interacts with O2 of uracil. Biochemical studies of wild type SpUP showed that substrate specificity is similar to that of EcUP, while EcUP is about sevenfold more efficient than SpUP. Biochemical studies on active site mutant SpUP showed that mutations of His169 reduced activity, while mutation of Lys162 abolished all activity, suggesting that negative charge in the transition state resides mostly on uracil O2. This is in contrast to EcUP for which transition state stabilization occurs mostly at O4.
Tran, Timothy H.; Christoffersen, S.; Allan, Paula W.; Parker, William B.; Piskur, Jure; Serra, I.; Terreni, M.; Ealick, Steven E.
A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1 mol L(-1) HCl for methyl mercury and 2 mol L(-1) HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical conditions including pH, amounts of biosorbent, sample volumes, etc., were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries were also investigated. The capacity of biosorbent for mercury(II) and methyl mercury was 4.8 and 3.4 mg g(-1). The detection limit (3 sigma) of the reagent blank for mercury(II) and methyl mercury was 2.1 and 1.5 ng L(-1). Preconcentration factor was calculated as 25. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure is performed by the analysis of standard reference material (NRCC-DORM 2 Dogfish Muscle). The procedure was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and environmental samples. PMID:19386416
Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Karaman, Isa; Soylak, Mustafa
Retapamulin had the lowest rate of spontaneous mutations by single-step passaging and the lowest parent and selected mutant MICs by multistep passaging among all drugs tested for all Staphylococcus aureus strains and three Streptococcus pyogenes strains which yielded resistant clones. Retapamulin has a low potential for resistance selection in S. pyogenes, with a slow and gradual propensity for resistance development in S. aureus.
Kosowska-Shick, Klaudia; Clark, Catherine; Credito, Kim; McGhee, Pamela; Dewasse, Bonifacio; Bogdanovich, Tatiana; Appelbaum, Peter C.
Streptococcus pyogenes (group A streptococcus [GAS]), a multiple-amino-acid-auxotrophic human pathogen, may face starvation for essential amino acids during various stages of the infection process. Since the response of GAS to such conditions is likely to influence pathogenetic processes, we set out to identify by transcriptional analyses genes and operons that are responsive to amino acid starvation and examined whether functionally meaningful response patterns can be ascertained. We discovered that GAS are capable of mounting a relA-independent amino acid starvation response that involves transcriptional modulation of a wide array of housekeeping genes as well as accessory and dedicated virulence genes. Housekeeping genes that were upregulated during starvation of both wild-type and relA mutant strains included the newly identified T-box members of the aminoacyl-tRNA synthetase genes, the genes for components of the tmRNA-mediated peptide tagging and proteolysis system for abnormal proteins (ssrA, smpB, clpP, and clpC), and the operons for the dnaK and groE groups of molecular chaperones. In addition to upregulation of the genes for oligopeptide permease (opp), intracellular peptidase (pepB), and the two-component regulator covRS reported previously (K. Steiner and H. Malke, Mol. Microbiol. 38:1004–1016, 2000), amino acid starvation stimulated the transcription of the growth phase-associated, virulence-regulatory fas operon, the streptolysin S operon (sag), and the gene for autoinducer-2 production protein (luxS). A prominent feature of operons exhibiting internal transcriptional termination (opp, fas, and sag) was starvation-promoted full-length transcription, a mechanism that improves the efficacy of these systems by increasing the level of coordinate transcription of functionally related genes. Based on these results, a regulatory network with feedback mechanisms is proposed that counteracts the stringent response, links the levels of key rate-limiting enzymes to virulence gene expression, and enables the organism in a dynamic way to take advantage of protein-rich environments provided by its human host. As several of the affected target genes are controlled by more than one regulator, fine modulation may result in accordance with the demands imposed by ecologically different colonization sites upon the adaptive capacity of the pathogen.
Steiner, Kerstin; Malke, Horst
Background The Streptococcus pyogenes or Group A Streptococcus (GAS) genome encodes three ABC transporters, namely, FtsABCD, MtsABC, and HtsABC, which share homology with iron transporters. MtsABC and HtsABC are believed to take up ferric (Fe3+) and manganese ions and heme, respectively, while the specificity of FtsABCD is unknown. Results Recombinant FtsB, the lipoprotein component of FtsABCD, was found to bind Fe3+ ferrichrome in a 1:1 stoichiometry. To investigate whether FtsABCD transports Fe3+ ferrichrome, GAS isogenic strains defective in lipoprotein gene ftsB and permease gene ftsC were generated, and the effects of the mutations on uptake of Fe3+ ferrichrome were examined using radioactive 55Fe3+ ferrichrome. FtsB was produced in the wild-type strain but not in the ftsB mutant, confirming the ftsB inactivation. While wild-type GAS took up 3.6 × 104 Fe3+ ferrichrome molecules per bacterium per min at room temperature, the ftsB and ftsC mutants did not have a detectable rate of Fe3+ ferrichrome uptake. The inactivation of ftsB or ftsC also decreased 55Fe3+ ferrichrome uptake by >90% under growth conditions in the case of limited uptake time. Complementation of the ftsB mutant with a plasmid carrying the ftsB gene restored FtsB production and 55Fe3+ ferrichrome association at higher levels compared with the parent strain. The inactivation of mtsA and htsA and Fe-restricted conditions enhanced the production of FtsB and Fe3+ ferrichrome uptake. Conclusion The FtsB protein bound Fe3+ ferrichrome, and inactivation of ftsB or ftsC, but not htsA or mtsA, diminished Fe3+ ferrichrome uptake, indicating that FtsABCD, but not HtsABC and MtsABC, is the transporter that takes up Fe3+ ferrichrome in GAS. Fe acquisition systems are virulence factors in many bacterial pathogens and are attractive vaccine candidates. The elucidation of the FtsABCD specificity advances the understanding of Fe acquisition processes in GAS and may help evaluating the GAS Fe acquisition systems as vaccine candidates.
Hanks, Tracey S; Liu, Mengyao; McClure, Michael J; Lei, Benfang
Streptococcus pyogenes (group A streptococci [GAS]) encounter many streptococcal species of the physiological microbial biome when entering the upper respiratory tract of humans, leading to the question how GAS interact with these bacteria in order to establish themselves at this anatomic site and initiate infection. Here we show that S. oralis and S. salivarius in direct contact assays inhibit growth of GAS in a strain-specific manner and that S. salivarius, most likely via bacteriocin secretion, also exerts this effect in transwell experiments. Utilizing scanning electron microscopy documentation, we identified the tested strains as potent biofilm producers except for GAS M49. In mixed-species biofilms, S. salivarius dominated the GAS strains, while S. oralis acted as initial colonizer, building the bottom layer in mixed biofilms and thereby allowing even GAS M49 to form substantial biofilms on top. With the exception of S. oralis, artificial saliva reduced single-species biofilms and allowed GAS to dominate in mixed biofilms, although the overall two-layer structure was unchanged. When covered by S. oralis and S. salivarius biofilms, epithelial cells were protected from GAS adherence, internalization, and cytotoxic effects. Apparently, these species can have probiotic effects. The use of Affymetrix array technology to assess HEp-2 cell transcription levels revealed modest changes after exposure to S. oralis and S. salivarius biofilms which could explain some of the protective effects against GAS attack. In summary, our study revealed a protection effect of respiratory tract bacteria against an important airway pathogen and allowed a first in vitro insight into local environmental processes after GAS enter the respiratory tract.
Fiedler, Tomas; Riani, Catur; Koczan, Dirk; Standar, Kerstin
Hyaluronan synthase (HAS), the enzyme responsible for the production of hyaluronic acid (HA), is a well-conserved membrane-bound protein in both prokaryotes and eukaryotes. This enzyme performs at least six discrete functions in producing a heterodisaccharide polymer of several million molecular weight and extruding it from the cell. Among the conserved motifs and domains within the Class I HAS family are four cysteine residues. Cysteines in many proteins are important in establishing and maintaining tertiary structure or in the coordination of catalytic functions. In the present study we utilized a combination of site-directed mutagenesis, chemical labeling, and kinetic analyses to determine the importance of specific Cys residues for catalysis and structure of the HA synthase from Streptococcus pyogenes (spHAS). The enzyme activity of spHAS was partially inhibited by cysteine-reactive chemical reagents such as N-ethylmaleimide. Quantitation of the number of Cys residues modified by these reagents, using MALDI-TOF mass spectrometry, demonstrated that there are no stable disulfide bonds in spHAS. The six Cys residues of spHAS were then mutated, individually and in various combinations, to serine or alanine. The single Cys-mutants were all kinetically similar to the wild-type enzyme in terms of their Vmax and Km values for HA synthesis. The Cys-null mutant, in which all Cys residues were mutated to alanine, retained ?66% of wild-type activity, demonstrating that despite their high degree of conservation within the HAS family, Cys residues are not absolutely necessary for HA biosynthesis by the spHAS enzyme.
Heldermon, Coy D.; Tlapak-Simmons, Valarie L.; Baggenstoss, Bruce A.; Weigel, Paul H.
The ExPortal protein secretion organelle in Streptococcus pyogenes is an anionic phospholipid-containing membrane microdomain enriched in Sec translocons and postsecretion protein biogenesis factors. Polymyxin B binds to and disrupts ExPortal integrity, resulting in defective secretion of several toxins. To gain insight into factors that influence ExPortal organization, a genetic screen was conducted to select for spontaneous polymyxin B-resistant mutants displaying enhanced ExPortal integrity. Whole-genome resequencing of 25 resistant mutants revealed from one to four mutations per mutant genome clustered primarily within a core set of 10 gene groups. Construction of mutants with individual deletions or insertions demonstrated that 7 core genes confer resistance and enhanced ExPortal integrity through loss of function, while 3 were likely due to gain of function and/or combinatorial effects. Core resistance genes include a transcriptional regulator of lipid biosynthesis, several genes involved in nutrient acquisition, and a variety of genes involved in stress responses. Two members of the latter class also function as novel regulators of the secreted SpeB cysteine protease. Analysis of the most frequently isolated mutation, a single nucleotide deletion in a track of 9 consecutive adenine residues in pstS, encoding a component of a high-affinity Pi transporter, suggests that this sequence functions as a molecular switch to facilitate stress adaptation. Together, these data suggest the existence of a membrane stress response that promotes enhanced ExPortal integrity and resistance to cationic antimicrobial peptides. PMID:24794568
Port, Gary C; Vega, Luis A; Nylander, Andrew B; Caparon, Michael G
In order to investigate for possible differences between paediatric and adult invasive Streptococcus pyogenes (iGAS) infections, a total of 142 cases were identified in 17 Greek hospitals during 2003-2007, of which 96 were children and 46 adults. Bacteraemia, soft tissue infections, streptococcal toxic shock syndrome (STSS), and necrotizing fasciitis were the main clinical presentations (67·6%, 45·1%, 13·4%, and 12·0% of cases, respectively). Bacteraemia and lymphadenitis were significantly more frequent in children (P=0·019 and 0·021, respectively), whereas STSS was more frequent in adults (P=0·017). The main predisposing factors in children were varicella and streptococcal pharyngotonsillitis (25% and 19·8%, respectively), as opposed to malignancy, intravenous drug abuse and diabetes mellitus in adults (19·6%, 15·2% and 10·9%, respectively). Of the two dominant emm-types, 1 and 12 (28·2% and 8·5%, respectively), the proportion of emm-type 12 remained stable during the study period, whereas emm-type 1 rates fluctuated considerably. Strains of emm-type 1 from children were associated with erythromycin susceptibility, STSS and intensive-care-unit admission, whereas emm-type 12 isolates from adults were associated with erythromycin and clindamycin resistance. Finally, specific emm-types were detected exclusively in adults or in children. In conclusion, several clinical and epidemiological differences were detected, that could prove useful in designing age-focused strategies for prevention and treatment of iGAS infections. PMID:23746128
Zachariadou, L; Stathi, A; Tassios, P T; Pangalis, A; Legakis, N J; Papaparaskevas, J
The human pathogen Streptococcus pyogenes produces diverse pili depending on the serotype. We investigated the assembly mechanism of FCT type 1 pili in a serotype M6 strain. The pili were found to be assembled from two precursor proteins, the backbone protein T6 and ancillary protein FctX, and anchored to the cell wall in a manner that requires both a housekeeping sortase enzyme (SrtA) and pilus-associated sortase enzyme (SrtB). SrtB is primarily required for efficient formation of the T6 and FctX complex and subsequent polymerization of T6, whereas proper anchoring of the pili to the cell wall is mainly mediated by SrtA. Because motifs essential for polymerization of pilus backbone proteins in other Gram-positive bacteria are not present in T6, we sought to identify the functional residues involved in this process. Our results showed that T6 encompasses the novel VAKS pilin motif conserved in streptococcal T6 homologues and that the lysine residue (Lys-175) within the motif and cell wall sorting signal of T6 are prerequisites for isopeptide linkage of T6 molecules. Because Lys-175 and the cell wall sorting signal of FctX are indispensable for substantial incorporation of FctX into the T6 pilus shaft, FctX is suggested to be located at the pilus tip, which was also implied by immunogold electron microscopy findings. Thus, the elaborate assembly of FCT type 1 pili is potentially organized by sortase-mediated cross-linking between sorting signals and the amino group of Lys-175 positioned in the VAKS motif of T6, thereby displaying T6 and FctX in a temporospatial manner.
Nakata, Masanobu; Kimura, Keiji Richard; Sumitomo, Tomoko; Wada, Satoshi; Sugauchi, Akinari; Oiki, Eiji; Higashino, Miharu; Kreikemeyer, Bernd; Podbielski, Andreas; Okahashi, Nobuo; Hamada, Shigeyuki; Isoda, Ryutaro; Terao, Yutaka; Kawabata, Shigetada
Streptococcus pyogenes Rgg is a transcriptional regulator that interacts with the cofactor LacD.1 to control growth phase-dependent expression of genes, including speB, which encodes a secreted cysteine protease. LacD.1 is thought to interact with Rgg when glycolytic intermediates are abundant in a manner that prevents Rgg-mediated activation of speB expression via binding to the promoter region. When the intermediates diminish, LacD.1 dissociates from Rgg and binds to the speB promoter to activate expression. The purpose of this study was to determine if Rgg bound to chromatin during the exponential phase of growth and, if so, to identify the binding sites. Rgg bound to 62 chromosomal sites, as determined by chromatin immunoprecipitation coupled with DNA microarrays. Thirty-eight were within noncoding DNA, including sites upstream of the genes encoding the M protein (M49), serum opacity factor (SOF), fibronectin-binding protein (SfbX49), and a prophage-encoded superantigen, SpeH. Each of these sites contained a promoter that was regulated by Rgg, as determined with transcriptional fusion assays. Purified Rgg also bound to the promoter regions of emm49, sof, and sfbX49 in vitro. Results obtained with a lacD.1 mutant showed that both LacD.1 and Rgg were necessary for the repression of emm49, sof, sfbX49, and speH expression. Overall, the results indicated that the DNA binding specificity of Rgg is responsive to environmental changes in a LacD.1-dependent manner and that Rgg and LacD.1 directly control virulence gene expression in the exponential phase of growth.
Anbalagan, Srivishnupriya; Dmitriev, Alexander; McShan, W. Michael; Dunman, Paul M.
The penicillin-binding proteins (PBPs) of Streptococcus pyogenes and two of its derived, stabilized (i.e., nonreverting) L forms, an osmotically fragile L form and a physiologic isotonic L form, were compared. The numbers of PBPs in the membranes of these organisms were 6, 4, and 2 for the coccus and the osmotically fragile and physiologic isotonic L forms, respectively. Likewise, the relative amounts of total PBPs were 1.00: 1.48:0.32 for this coccus and the osmotically fragile and physiologic isotonic L forms, respectively. The two largest PBPs (PBPs 1 and 2) of the coccus were absent in both L forms, while the smallest PBPs (PBPs 5 and 6) were found in all three membranes. Deacylation (half-life) of three of the four PBPs in the osmotically fragile L form membrane required a significantly longer time than did deacylation of these presumed identical enzymes in the parental coccal membrane. Conversely, there was no such difference between the only two PBPs of the physiologic isotonic L form and the same coccal membrane proteins. Intact cells of all three organisms secreted PBPs and what appeared to be penicilloic acid and a minimal amount of free penicillin. A greater amount of these PBPs was secreted by both L forms than by the coccus. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns and ratios of secreted PBPs were identical to those from labeled membrane preparations. These differences are correlated with some of our previous findings and are discussed in terms of inhibition of cell wall synthesis and resulting membrane changes in these two derived, stabilized coccal L forms.
Leon, O; Panos, C
In the human-pathogenic bacterium Streptococcus pyogenes, the tagatose bisphosphate aldolase LacD.1 likely originated through a gene duplication event and was adapted to a role as a metabolic sensor for regulation of virulence gene transcription. Although LacD.1 retains enzymatic activity, its ancestral metabolic function resides in the LacD.2 aldolase, which is required for the catabolism of galactose. In this study, we compared these paralogous proteins to identify characteristics correlated with divergence and novel function. Surprisingly, despite the fact that these proteins have identical active sites and 82% similarity in amino acid sequence, LacD.1 was less efficient at cleaving both fructose and tagatose bisphosphates. Analysis of kinetic properties revealed that LacD.1's adaptation was associated with a decrease in kcat and an increase in Km. Construction and analysis of enzyme chimeras indicated that non-active-site residues previously associated with the variable activities of human aldolase isoenzymes modulated LacD.1's affinity for substrate. Mutant LacD.1 proteins engineered to have LacD.2-like levels of enzymatic efficiency lost the ability to function as regulators, suggesting that an alteration in efficiency was required for adaptation. In competition under growth conditions that mimic a deep-tissue environment, LacD.1 conferred a significant gain in fitness that was associated with its regulatory activity. Taken together, these data suggest that LacD.1's adaptation represents a form of neofunctionalization in which duplication facilitated the gain of regulatory function important for growth in tissue and pathogenesis.
Non-instrumental immunoassays based on immunofiltration and microtiter particle agglutination (MPA) techniques have been developed using coloured polyacrolein latex. These methods have been applied to the quantification of the group-specific polysaccharide (PS) of S. pyogenes (group A streptococcus) and compared with standard ELISA tests. The most efficient method was MPA; as little as 0.05 ng A-PS/ml could be detected in 1.5 h. In comparison with ELISA test, the sensitivity of MPA was 10 times higher and the procedure was much simpler. The sensitivity of immunofiltration assay using both enzyme and latex conjugates was shown to be the same (50 ng/ml A-PS) and the duration of the assay 3-5 min. No cross-reactions of latex conjugates with non A streptococcus cell lysates have been observed. The developed methods are rapid, robust, easy to perform, don't need any sophisticated equipment and specially trained staff. PMID:7993377
Pvlova, I S; Lukin, Iu V; Kovalenko, V A; Avdeev, D N; Kul'shin, V A; Zubov, V P
To evade host immune mechanisms, many bacteria secrete immunomodulatory enzymes. Streptococcus pyogenes, one of the most common human pathogens, secretes a large endoglycosidase, EndoS, which removes carbohydrates in a highly specific manner from IgG antibodies. This modification renders antibodies incapable of eliciting host effector functions through either complement or Fc ? receptors, providing the bacteria with a survival advantage. On account of this antibody-specific modifying activity, EndoS is being developed as a promising injectable therapeutic for autoimmune diseases that rely on autoantibodies. Additionally, EndoS is a key enzyme used in the chemoenzymatic synthesis of homogenously glycosylated antibodies with tailored Fc ? receptor-mediated effector functions. Despite the tremendous utility of this enzyme, the molecular basis of EndoS specificity for, and processing of, IgG antibodies has remained poorly understood. Here, we report the X-ray crystal structure of EndoS and provide a model of its encounter complex with its substrate, the IgG1 Fc domain. We show that EndoS is composed of five distinct protein domains, including glycosidase, leucine-rich repeat, hybrid Ig, carbohydrate binding module, and three-helix bundle domains, arranged in a distinctive V-shaped conformation. Our data suggest that the substrate enters the concave interior of the enzyme structure, is held in place by the carbohydrate binding module, and that concerted conformational changes in both enzyme and substrate are required for subsequent antibody deglycosylation. The EndoS structure presented here provides a framework from which novel endoglycosidases could be engineered for additional clinical and biotechnological applications. PMID:24753590
Trastoy, Beatriz; Lomino, Joseph V; Pierce, Brian G; Carter, Lester G; Günther, Sebastian; Giddens, John P; Snyder, Greg A; Weiss, Thomas M; Weng, Zhiping; Wang, Lai-Xi; Sundberg, Eric J
The pili expressed on the surface of the human pathogen Streptococcus pyogenes play an important role in host cell attachment, colonisation and pathogenesis. These pili are built from two or three components, an adhesin subunit at the tip, a major pilin that forms a polymeric shaft, and a basal pilin that is attached to the cell wall. Assembly is carried out by specific sortase (cysteine transpeptidase) enzyme. These components are encoded in a small gene cluster within the S. pyogenes genome, often together with another protein, SipA, whose function is unknown. We show through functional assays, carried out by expressing the S. pyogenes pilus components in Lactococcus lactis, SipA from the clinically important M1T1 strain is essential for pilus assembly, and that SipA function is likely to be conserved in all S. pyogenes. From the crystal structure of SipA we confirm that SipA belongs to the family of bacterial signal peptidases (SPases), which process the signal-peptides of secreted proteins. In contrast to a previous arm-swapped SipA dimer, this present structure shows that its principal domain closely resembles the catalytic domain of SPases and has a very similar peptide-binding cleft, but it lacks the catalytic Ser and Lys residues characteristic of SPases. In SipA these are replaced by Asp and Gly residues, which play no part in activity. We propose that SipA functions by binding a key component at the bacterial cell surface, in a conformation that facilitates pilus assembly.
Young, Paul G.; Proft, Thomas; Harris, Paul W. R.; Brimble, Margaret A.; Baker, Edward N.
The hemolytic Streptococcus pyogenes can use a variety of heme compounds as an iron source. In this study, we investigate hemoprotein utilization by S. pyogenes. We demonstrate that surface proteins contribute to the binding of hemoproteins to S. pyogenes. We identify an ABC transporter from the iron complex family named sia for streptococcal iron acquisition, which consists of a lipoprotein (siaA), membrane permease (siaB), and ATPase (siaC). The sia transporter is part of a highly conserved, iron regulated, 10-gene operon. SiaA, which was localized to the cell membrane, could specifically bind hemoglobin. The operon's first gene encodes a novel bacterial protein that bound hemoglobin, myoglobin, heme-albumin, and hemoglobin-haptoglobin (but not apo-haptoglobin) and therefore was named Shr, for streptococcal hemoprotein receptor. PhoZ fusion and Western blot analysis showed that Shr has a leader peptide and is found in both membrane-bound and soluble forms. An M1 SF370 strain with a polar mutation in shr was more resistant to streptonigrin and hydrogen peroxide, suggesting decreased iron uptake. The addition of hemoglobin to the culture medium increased cell resistance to hydrogen peroxide in SF370 but not in the mutant, implying the sia operon may be involved in hemoglobin-dependent resistance to oxidative stress. The shr mutant demonstrated reduced hemoglobin binding, though cell growth in iron-depleted medium supplemented with hemoglobin, whole blood, or ferric citrate was not affected, suggesting additional systems are involved in hemoglobin utilization. SiaA and Shr are the first hemoprotein receptors identified in S. pyogenes; their possible role in iron capture is discussed.
Bates, Christopher S.; Montanez, Griselle E.; Woods, Charles R.; Vincent, Rebecca M.; Eichenbaum, Zehava
Microbial pathogens often exploit human complement regulatory proteins such as factor H (FH) and factor H-like protein 1 (FHL-1) for immune evasion. Fba is an FH and FHL-1 binding protein expressed on the sur- face of the human pathogenic bacterium Streptococcus pyogenes, a common agent of pharyngeal, skin, and soft- tissue infections. Fba has been shown to contribute to phagocytosis
Lin Wei; Vinod Pandiripally; Eugene Gregory; Micaya Clymer; David Cue
Streptococcus pyogenes is a human pathogen that causes various diseases. Numerous virulence factors secreted by S. pyogenes are involved in pathogenesis. The peroxide regulator (PerR) is associated with the peroxide resistance response and pathogenesis, but little is known about the regulation of the secretome involved in virulence. To investigate how PerR regulates the expression of the S. pyogenes secretome involved in virulence, a perR deficient mutant was used for comparative secretomic analysis with a wild-type strain. The conditioned medium containing secreted proteins of a wild-type strain and a perR deficient mutant at the stationary phase were collected for two-dimensional gel electrophoresis analysis, where protease inhibitors were applied to avoid the degradation of extracellular proteins. Differentially expressed protein spots were identified by liquid chromatography electrospray ionization tandem MS. More than 330 protein spots were detected on each gel. We identified 25 unique up-regulated proteins and 13 unique down-regulated proteins that were directly or indirectly controlled by the PerR regulator. Among these identified proteins, mitogen factor 3 (MF3), was selected to verify virulence and the expression of gene products. The data showed that MF3 protein levels in conditioned medium, as measured by immunoblot analysis, correlated well with protein levels determined by two-dimensional gel electrophoresis analysis. We also demonstrated that PerR bound to the promoter region of the mf3 gene. The result of an infection model showed that virulence was attenuated in the mf3 deficient mutant. Additional growth data of the wild-type strain and the mf3 deficient mutant suggested that MF3 played a role in digestion of exogenous DNA for promoting growth. To summarize, we conclude that PerR can positively regulate the expression of the secreted protein MF3 that contributes to the virulence in S. pyogenes. The analysis of the PerR-regulated secretome provided key information for the elucidation of the host-pathogen interactions and might assist in the development of potential chemotherapeutic strategies to prevent or treat streptococcal diseases.
Wen, Yao-Tseng; Tsou, Chih-Cheng; Kuo, Hsin-Tzu; Wang, Jie-Siou; Wu, Jiunn-Jong; Liao, Pao-Chi
The resurgence of invasive disease caused by Streptococcus pyogenes (group A Streptococcus [GAS]) in the past 30 years has paralleled the emergence and global dissemination of the highly virulent M1T1 clone. The GAS M1T1 clone has diverged from the ancestral M1 serotype by horizontal acquisition of two unique bacteriophages, encoding the potent DNase Sda1/SdaD2 and the superantigen SpeA, respectively. The phage-encoded DNase promotes escape from neutrophil extracellular traps and is linked to enhanced virulence of the M1T1 clone. In this study, we successfully used in vitro lysogenic conversion to transfer the Sda1-encoding phage from the M1T1 clonal strain 5448 to the nonclonal M1 isolate SF370 and determined the impact of this horizontal gene transfer event on virulence. Although Sda1 was expressed in SF370 lysogens, no capacity of the phage-converted strain to survive human neutrophil killing, switch to a hyperinvasive covRS mutant form, or cause invasive lethal infection in a humanized plasminogen mouse model was observed. This work suggests that the hypervirulence of the M1T1 clone is due to the unique synergic effect of the M1T1 clone bacteriophage-specific virulence factor Sda1 acting in concert with the M1T1 clone-specific genetic scaffold.
Venturini, Carola; Ong, Cheryl-lynn Y.; Gillen, Christine M.; Ben-Zakour, Nouri L.; Maamary, Peter G.; Nizet, Victor; Beatson, Scott A.
One hundred seventy-nine Streptococcus pyogenes isolates recovered from scarlet fever patients from 1996 to 1999 in central Taiwan were characterized by emm, Vir, and pulsed-field gel electrophoresis (PFGE) typing methods. The protocols for Vir and PFGE typing were standardized. A database of the DNA fingerprints for the isolates was established. Nine emm or emm-like genes, 19 Vir patterns, and 26 SmaI PFGE patterns were detected among the isolates. Among the three typing methods, PFGE was the most discriminatory. However, it could not completely replace Vir typing because some isolates with identical PFGE patterns could be further differentiated into several Vir patterns. The prevalent emm types were emm4 (n = 81 isolates [45%]), emm12 (n = 64 [36%]), emm1 (n = 14 [8%]), and emm22 (n = 13 [7%]). Some emm type isolates could be further differentiated into several emm-Vir-PFGE genotypes; however, only one genotype in each emm group was usually predominant. DNA from nine isolates was resistant to SmaI digestion. Further PFGE analysis with SgrAI showed that the SmaI digestion-resistant strains could be derived from indigenous strains by horizontal transfer of exogenous genetic material. The emergence of the new strains could have resulted in an increase in scarlet fever cases in central Taiwan since 2000. The emm sequences, Vir, and PFGE pattern database will serve as a basis for information for the long-term evolutionary study of local S. pyogenes strains.
Chiou, Chien-Shun; Liao, Tsai-Ling; Wang, Tzu-Hui; Chang, Hsiu-Li; Liao, Jui-Cheng; Li, Chun-Chin
The Streptococcus pyogenes collagen type I-binding protein Cpa (collagen-binding protein of group A streptococci) expressed by 28 serotypes of group A streptococci has been extensively characterized at the gene and protein levels. Evidence for three distinct families of cpa genes was found, all of which shared a common sequence encoding a 60-amino acid domain that accounted for selective binding to type I collagen. Surface plasmon resonance-based affinity measurements and functional studies indicated that the expression of Cpa was consistent with an attachment role for bacteria to tissue containing collagen type I. A cpa mutant displayed a significantly decreased internalization rate when incubated with HEp-2 cells but had no effect on the host cell viability. By utilizing serum from patients with a positive titer for streptolysin/DNase antibody, an increased anti-Cpa antibody titer was noted for patients with a clinical history of arthritis or osteomyelitis. Taken together, these results suggest Cpa may be a relevant matrix adhesin contributing to the pathogenesis of S. pyogenes infection of bones and joints. PMID:16040603
Kreikemeyer, Bernd; Nakata, Masanobu; Oehmcke, Sonja; Gschwendtner, Caroline; Normann, Jana; Podbielski, Andreas
MtsABC is a Streptococcus pyogenes ABC transporter which was previously shown to be involved in iron and zinc accumulation. In this study, we showed that an mtsABC mutant has impaired growth, particularly in a metal-depleted medium and an aerobic environment. In metal-depleted medium, growth was restored by the addition of 10 ?M MnCl2, whereas other metals had modest or no effect. A characterization of metal radioisotope accumulation showed that manganese competes with iron accumulation in a dose-dependent manner. Conversely, iron competes with manganese accumulation but to a lesser extent. The mutant showed a pronounced reduction (>90%) of 54Mn accumulation, showing that MtsABC is also involved in Mn transport. Using paraquat and hydrogen peroxide to induce oxidative stress, we show that the mutant has an increased susceptibility to reactive oxygen species. Moreover, activity of the manganese-cofactored superoxide dismutase in the mutant is reduced, probably as a consequence of reduced intracellular availability of manganese. The enzyme functionality was restored by manganese supplementation during growth. The mutant was also attenuated in virulence, as shown in animal experiments. These results emphasize the role of MtsABC and trace metals, especially manganese, for S. pyogenes growth, susceptibility to oxidative stress, and virulence.
Janulczyk, Robert; Ricci, Susanna; Bjorck, Lars
Activities of a New Fluoroketolide, HMR 3787, and Its (Des)-Fluor Derivative RU 64399 Compared to Those of Telithromycin, Erythromycin A, Azithromycin, Clarithromycin, and Clindamycin against Macrolide-Susceptible or -Resistant Streptococcus pneumoniae and S. pyogenes
Activities of HMR 3787 and RU 64399 were compared to those of three macrolides, telithromycin, and clindamycin against 175 Streptococcus pneumoniae isolates and 121 Streptococcus pyogenes isolates. HMR3787 and telithromycin were the most active compounds tested against pneumococci. Telithromycin and RU 64399 were equally active against macrolide-susceptible (MICs, 0.008 to 0.06 ?g/ml) and -resistant S. pyogenes isolates, but HMR 3787 had lower MICs for ermB strains.
Nagai, Kensuke; Davies, Todd A.; Ednie, Lois M.; Bryskier, Andre; Palavecino, Elizabeth; Jacobs, Michael R.; Appelbaum, Peter C.
Streptococcus pyogenes (group A streptococcus, GAS) is a very important human pathogen with remarkable adaptation capabilities. Survival within the harsh host surroundings requires sensing potential on the bacterial side, which leads in particular to coordinately regulated virulence factor expression. GAS 'stand-alone' response regulators (RRs) and two-component signal transduction systems (TCSs) link the signals from the host environment with adaptive responses of the bacterial cell. Numerous putative regulatory systems emerged from GAS genome sequences. Only three RRs [Mga, RofA-like protein (RALP) and Rgg/RopB] and three TCSs (CsrRS/CovRS, FasBCAX and Ihk/Irr) have been studied in some detail with respect to their growth-phase-dependent activity and their influence on GAS-host cell interaction. In particular, the Mga-, RALP- and Rgg/RopB-regulated pathways display interconnected activities that appear to influence GAS colonization, persistence and spreading mechanisms, in a growth-phase-related fashion. Here, we have summarized our current knowledge about these RRs and TCSs to highlight the questions that should be addressed in future research on GAS pathogenicity. PMID:12781526
Kreikemeyer, Bernd; McIver, Kevin S; Podbielski, Andreas
Streptococcus pyogenes (group A streptococcus [GAS]) is a highly virulent Gram-positive bacterium. For successful infection, GAS expresses many virulence factors, which are clustered together with transcriptional regulators in distinct genomic regions. Ralp3 is a central regulator of the ERES region. In this study, we investigated the role of Ralp3 in GAS M49 pathogenesis. The inactivation of Ralp3 resulted in reduced attachment to and internalization into human keratinocytes. The ?ralp3 mutant failed to survive in human blood and serum, and the hyaluronic acid capsule was slightly decreased. In addition, the mutant showed a lower binding capacity to human plasminogen, and the SpeB activity was significantly decreased. Complementation of the ?ralp3 mutant restored the wild-type phenotype. The transcriptome and quantitative reverse transcription-PCR analysis of the serotype M49 GAS strain and its isogenic ?ralp3 mutant identified 16 genes as upregulated, and 43 genes were found to be downregulated. Among the downregulated genes, there were open reading frames encoding proteins involved in metabolism (e.g., both lac operons and the fru operon), genes encoding lantibiotics (e.g., the putative salivaricin operon), and ORFs encoding virulence factors (such as the whole Mga core regulon and further genes under Mga control). In summary, the ERES region regulator Ralp3 is an important serotype-specific transcriptional regulator for virulence and metabolic control.
Siemens, Nikolai; Fiedler, Tomas; Normann, Jana; Klein, Johannes; Munch, Richard; Patenge, Nadja
One hundred and seven clinical isolates of Streptococcus pyogenes, 80 susceptible to macrolides and 27 resistant to erythromycin A (MIC >0.5 mg\\/ml), were examined. The erythromycin A-lincomycin double-disk test assigned 7 resistant strains to the M-phenotype, 8 to the inducible macrolide, lincosamide, and strepto- gramin B resistance (iMLSB) phenotype, and 12 to the constitutive MLSB resistance (cMLSB) phenotype. MICs of
PASCALE BEMER-MELCHIOR; MARIE-EMMANUELLE JUVIN; SANDRINE TASSIN; ANDRE BRYSKIER; GIAN CARLO SCHITO; H.-B. Drugeon
Recurrent pyogenic cholangitis (RPC) is characterized by repeated infections of the biliary system with the formation of stones and strictures. The management aims are to treat acute cholangitis, clear the biliary ductal debris and calculi, and eliminate predisposing factors of bile stasis. Operative options include hepatectomy and biliary drainage procedures or a combination of both; nonoperative options include endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) guided procedures. This current study compares the operative and the nonoperative management outcomes in patients with RPC in 80 consecutive patients. In addition, we aim to evaluate our approach to the management of RPC over the past decade, according to the various degrees of severity and extent of the disease, and identify the patterns of recurrence in this complex clinical condition. Initial failure rate in terms of residual stone of operative compared with nonoperative treatment was 10.2% versus 32.3% (P = 0.020). Long-term failure rate for operative compared with non-operative treatment was 20.4% versus 61.3% (P = 0.010). Based on multivariate logistic regression, the only significant factors associated with failure were bilaterality of disease (OR: 8.101, P = 0.007) and nonoperative treatment (OR: 26.843, P = 0.001). The median time to failure of the operative group was 48 months as compared to 20 months in the nonoperative group (P < 0.010). Thus operative treatment is a durable option in long-term resolution of disease. Hepatectomy is the preferred option to prevent recurrent disease. However, biliary drainage procedures are also an effective treatment option. The utility of nonoperative treatment can achieve a reasonable duration of disease free interval with minimal complications, albeit inferior to operative management.
Koh, Ye Xin; Chiow, Adrian Kah Heng; Chok, Aik Yong; Lee, Lip Seng; Tan, Siong San; Ibrahim, Salleh
Selected reaction monitoring mass spectrometry (SRM-MS) is a targeted proteomics technology used to identify and quantify proteins with high sensitivity, specificity and high reproducibility. Execution of SRM-MS relies on protein-specific SRM assays, a set of experimental parameters that requires considerable effort to develop. Here we present a proteome-wide SRM assay repository for the gram-positive human pathogen group A Streptococcus. Using a multi-layered approach we generated SRM assays for 10,412 distinct group A Streptococcus peptides followed by extensive testing of the selected reaction monitoring assays in >200 different group A Streptococcus protein pools. Based on the number of SRM assay observations we created a rule-based selected reaction monitoring assay-scoring model to select the most suitable assays per protein for a given cellular compartment and bacterial state. The resource described here represents an important tool for deciphering the group A Streptococcus proteome using selected reaction monitoring and we anticipate that concepts described here can be extended to other pathogens.
Karlsson, Christofer; Malmstrom, Lars; Aebersold, Ruedi; Malmstrom, Johan
The M protein is an important surface-located virulence factor of Streptococcus pyogenes, the group A streptococcus (GAS). Expression of M protein is primarily controlled by Mga, a transcriptional activator protein. A recent report suggested that the sag locus, which includes nine genes necessary and sufficient for production of streptolysin S, another GAS virulence factor, is also needed for transcription of emm, encoding the M protein (Z. Li, D. D. Sledjeski, B. Kreikemeyer, A. Podbielski, and M. D. Boyle, J. Bacteriol. 181:6019–6027, 1999). To investigate this in more detail, we constructed an insertion-deletion mutation in sagA, the first gene in the sag locus, in the M6 strain JRS4. The resulting strain, JRS470, produced no detectable streptolysin S and showed a drastic reduction in cell surface-associated M protein, as measured by cell aggregation and Western blot analysis. However, transcription of the emm gene was unaffected by the sagA mutation. Detailed analysis with monoclonal antibodies and an antipeptide antibody showed that the M protein in the sagA mutant strain was truncated so that it lacks the C-repeat region and the C-terminal domain required for anchoring it to the cell surface. This truncated M protein was largely found, as expected, in the culture supernatant. Lack of surface-located M protein made the sagA mutant strain susceptible to phagocytosis. Thus, although sagA does not affect transcription of the M6 protein gene, it is needed for the surface localization of this important virulence factor.
Biswas, Indranil; Germon, Pierre; McDade, Kathleen; Scott, June R.
Antimicrobial Susceptibilities of 1,684 Streptococcus pneumoniae and 2,039 Streptococcus pyogenes Isolates and Their Ecological Relationships: Results of a 1-Year (1998-1999) Multicenter Surveillance Study in Spain
A nationwide multicenter susceptibility surveillance study which included 1,684 Streptococcus pneumoniae and 2,039 S. pyogenes isolates was carried out over 1 year in order to assess the current resistance patterns for the two most important gram-positive microorganisms responsible for community-acquired infections in Spain. Susceptibility testing was done by a broth microdilution method according to National Committee for Clinical Laboratory Standards M100-S10 interpretative criteria. For S. pneumoniae, the prevalences of highly resistant strains were 5% for amoxicillin and amoxicillin-clavulanic acid; 7% for cefotaxime; 22% for penicillin; 31% for cefuroxime; 35% for erythromycin, clarithromycin, and azithromycin; and 42% for cefaclor. For S. pyogenes, the prevalence of erythromycin resistance was 20%. Efflux was encountered in 90% of S. pyogenes and 5% of S. pneumoniae isolates that exhibited erythromycin resistance. Erythromycin resistance was associated with clarithromycin and azithromycin in both species, regardless of phenotype. Despite the different nature of the mechanisms of resistance, a positive correlation (r = 0.612) between the two species in the prevalence of erythromycin resistance was found in site-by-site comparisons, suggesting some kind of link with antibiotic consumption. Regarding ciprofloxacin, the MIC was ?4 ?g/ml for 7% of S. pneumoniae and 3.5% of S. pyogenes isolates. Ciprofloxacin resistance (MIC, ?4 ?g/ml) was significantly (P < 0.05) associated with macrolide resistance in both S. pyogenes and S. pneumoniae and with penicillin nonsusceptibility in S. pneumoniae.
Perez-Trallero, E.; Fernandez-Mazarrasa, C.; Garcia-Rey, C.; Bouza, E.; Aguilar, L.; Garcia-de-Lomas, J.; Baquero, F.
Epidemiology and clinical characteristics of invasive Group A streptococcal infections (IGASI) are highly variable. Long-term studies are needed to understand the interplay between epidemiology and virulence. In a population-based study of IGASI in Iceland from 1975 to 2012, 288 cases were identified by positive cultures from normally sterile body sites. Charts were reviewed retrospectively and emm-types of viable Streptococcus pyogenes isolates (n=226) determined. Comparing the first and last decade of the study period, IGASI incidence increased from 1.09 to 3.96 cases per 100,000 inhabitants per year. The most common were emm types 1 (25%), 28 (11%) and 89 (11%); emm1 strains were most likely to cause severe infections. Infections in adults were significantly more likely to be severe during the seasonal peak from January to April (risk ratio: 2.36, 95% confidence interval: 1.34–4.15). Significant seasonal variability in severity was noted among patients with diagnosis of sepsis, respiratory infection and cellulitis, with 38% of severe infections in January to April compared with 16% in other months (p<0.01). A seasonal increase in severity of IGASI suggested that generalised seasonal increase in host susceptibility, rather than introduction of more virulent strains may play a role in the pathogenesis of these potentially fatal infections. PMID:24821122
Olafsdottir, L B; Erlendsdóttir, H; Melo-Cristino, J; Weinberger, D M; Ramirez, M; Kristinsson, K G; Gottfredsson, M
Treponema denticola is a major pathogen of chronic periodontitis. Analysis of the T. denticola genome revealed a gene orthologous with a cysteine protease-encoding gene from Streptococcus pyogenes (IdeS). IdeS interferes with IgG-dependent opsonophagocytosis by specific cleavage of IgG molecules. Analysis of this gene (termed ideT) revealed it to encode a two-domain protein whose N-terminus is composed of tandem immunoglobulin-like domains followed by a C-terminal IdeS-like protease domain. In this study we show that during secretion the IdeT protein is processed into an N-terminal fragment which remains associated with the cell, and a C-terminal part released into the medium. Although the secreted domain of IdeT, termed dentipain, shows only 25% identity to the IdeS protease, the putative catalytic cysteine and histidine residues are strongly conserved. Recombinant dentipain cleaves the insulin ?-chain, an activity which is inhibited by E-64, a diagnostic inhibitor of cysteine proteases. Apart from insulin no cleavage of other protein substrates was detected, suggesting that dentipain has oligopeptidase activity. A mutant strain was constructed expressing a modified IdeT variant, the dentipain domain of which was deleted. This strain was found to be significantly reduced in its abscess-forming activity compared with the parental strain in a murine abscess model, suggesting that dentipain contributes to the virulence of T. denticola. PMID:20635859
Ishihara, Kazuyuki; Wawrzonek, Katarzyna; Shaw, Lindesey N; Inagaki, Satoru; Miyamoto, Meguru; Potempa, Jan
Background The Streptococcus pyogenes (group A streptococci, GAS) two-component signal transduction system CovRS has been described to be important for pathogenesis of this exclusively human bacterial species. If this system acts uniquely in all serotypes is currently unclear. Presence of serotype- or strain-dependent regulatory circuits and polarity is an emerging scheme in Streptococcus pyogenes pathogenesis. Thus, the contribution of the sensor kinase (CovS) of the global regulatory two-component signal transduction system CovRS on pathogenesis of several M serotypes was investigated. Results CovS mutation uniformly repressed capsule expression and hampered keratinocyte adherence in all tested serotypes. However, a serotype- and even strain-dependent contribution on survival in whole human blood and biofilm formation was noted, respectively. Conclusions These data provide new information on the action of the CovS sensor kinase and revealed that its activity on capsule expression and keratinocyte adherence is uniform across serotypes, whereas the influence on biofilm formation and blood survival is serotype or even strain dependent. This adds the CovRS system to a growing list of serotype-specific acting regulatory loci in S. pyogenes.
In order to better characterize bacteremic cellulitis caused by Streptococcus pneumoniae, a review was conducted of 10 cases of bacteremic pneumococcal cellulitis, which represented 0.9% of all cases of pneumococcal\\u000a bacteremia (n=1,076) and 3.2% of all cases of community-acquired bacteremic cellulitis (n=312) that occurred in the Hospital de Bellvitge, Barcelona, from 1984 to 2001. In addition to these 10 cases,
O. Capdevila; I. Grau; M. Vadillo; M. Cisnal; R. Pallares
The aim of this study was to examine the gene transfer potential of mef(A)-containing Tn120.3 to macrolide-susceptible Streptococcus pyogenes belonging to different emm types. Using the filter mating technique, Tn1207.3 was transferred by conjugation to 23 macrolide-susceptible recipients representing 11 emm types. PCR analysis confirmed the presence of the mef(A) gene and the comEC junction regions of the Tn1207.3 insertion in resultant transconjugants. Significant variation was found in the transfer frequency of Tn1207.3 to different Strep. pyogenes strains, and this phenomenon may contribute to the differences in mef(A) frequency observed among clinical isolates. Significance and impact of the study: The spread of antimicrobial resistance among pathogenic bacteria is an important problem, but the mechanisms of horizontal transfer between strains and species are often poorly understood. For instance, little is known on how macrolide resistance spreads between strains of the human pathogen Strep. pyogenes and why certain strains more commonly display resistance than others. Here, we show that Strep. pyogenes strains vary greatly in their ability to acquire a transposon encoding macrolide resistance by horizontal gene transfer in vitro. These data provide a novel insight into the transfer of antibiotic resistance between bacterial strains and offer an explanation for the differences in the frequency of resistance determinates and resistance seen among clinical isolates. PMID:24383794
Hadjirin, N F; Harrison, E M; Holmes, M A; Paterson, G K
Hospital- and community-acquired, complicated skin and soft tissue infections, often attributed to Staphylococcus aureus and Streptococcus pyogenes, present a significant health burden that is associated with increased health care costs and mortality. As these two species are difficult to discern on diagnosis and are associated with differential profiles of drug resistance, the development of an efficacious antibacterial agent that targets both organisms is a high priority. Herein we describe a structure-based drug development effort that has produced highly potent inhibitors of dihydrofolate reductase from both species. Optimized propargyl-linked antifolates containing a key pyridyl substituent display antibacterial activity against both methicillin-resistant S. aureus and S. pyogenes at MIC values below 0.1 µg/mL and minimal cytotoxicity against mammalian cells. Further evaluation against a panel of clinical isolates shows good efficacy against a range of important phenotypes such as hospital- and community-acquired strains as well as strains resistant to vancomycin.
Scocchera, Eric W.; Martin, Brooke D.; Swain III, P. Whitney; Alverson, Jeremy B.; Priestley, Nigel D.; Anderson, Amy C.; Wright, Dennis L.
The biochemical characteristics of 172 clinical isolates of group A, C, F, or G or "nongroupable" beta-hemolytic streptococci were examined. Among these isolates, 91 were identified as beta-hemolytic strains of Streptococcus milleri. The remaining isolates included 20 Streptococcus pyogenes, 21 Streptococcus equisimilis, 37 large-colony group G streptococci, and 3 unidentified nongroupable isolates. A majority (84%) of the S. milleri strains possessed Lancefield group antigen (3 A, 27 C, 41 F, and 5 G), whereas 15 S. milleri strains (16%) were nongroupable. Serological tests did not differentiate S. milleri isolates with group A, C, or G antigen from S. pyogenes (group A), S. equisimilis (group C), or large-colony group G streptococci. Biochemical tests which were found useful for differentiation included the Voges-Proskauer test, hydrolysis of pyroglutamic acid and beta-D-glucuronide, bacitracin susceptibility, and acid production from ribose. S. milleri represented 56% of the group C, 100% of the group F, and 83% of the nongroupable beta-hemolytic streptococci isolated in our clinical laboratory, whereas the incidence of S. milleri among group A and group G streptococci was estimated to be low. The role of beta-hemolytic S. milleri as a cause of human infection remains obscured by the failure to routinely differentiate S. milleri from other beta-hemolytic streptococci.
Lawrence, J; Yajko, D M; Hadley, W K
Ferric uptake regulator (Fur) and Fur-like proteins form an important family of transcriptional regulators in many bacterial species. In this work we have characterized a Fur-like protein, the peroxide regulator PerR, in an M1 serotype of Streptococcus pyogenes. To determine the role of PerR in S. pyogenes, we inactivated the gene by allelic replacement. PerR-deficient bacteria showed 48% reduction of 55Fe incorporation from the culture medium. Transcriptional analysis revealed that mtsA, encoding a metal-binding protein of an ABC transporter in S. pyogenes, was transcribed at lower levels than were wild-type cells. Although total iron accumulation was reduced, the growth of the mutant strain was not significantly hampered. The mutant showed hyperresistance to hydrogen peroxide, and this response was induced in wild-type cells by growth in aerobiosis, suggesting that PerR acts as an oxidative stress-responsive repressor. PerR may also participate in the response to superoxide stress, as the perR mutant was more sensitive to the superoxide anion and had a reduced transcription of sodA, which encodes the sole superoxide dismutase of S. pyogenes. Complementation of the mutation with a functional perR gene restored 55Fe incorporation, response to peroxide stress, and transcription of both mtsA and sodA to levels comparable to those of wild-type bacteria. Finally, the perR mutant was attenuated in virulence in a murine air sac model of infection (P < 0.05). These results demonstrate that PerR is involved in the regulation of iron homeostasis and oxidative stress responses and that it contributes to the virulence of S. pyogenes.
Ricci, Susanna; Janulczyk, Robert; Bjorck, Lars
Bacterially derived triple-helical, collagen-like proteins are attractive as potential biomedical materials. The collagen-like domain of the Scl2 protein from S. pyogenes lacks any specific binding sites for mammalian cells yet possesses the inherent structural integrity of the collagen triple-helix of animal collagens. It can, therefore, be considered as a structurally-stable "blank slate" into which various defined, biological sequences, derived from animal collagens, can be added by substitutions or insertions, to enable production of novel designed materials to fit specific functional requirements. In the present study, we have used site directed mutagenesis to substitute two functional sequences, one for heparin binding and the other for integrin binding, into different locations in the triple-helical structure. This provided three new constructs, two containing the single substitutions and one containing both substitutions. The stability of these constructs was marginally reduced when compared to the unmodified sequence. When compared to the unmodified bacterial collagen, both the modified collagens that contain the heparin binding site showed marked binding of fluorescently labeled heparin. Similarly, the modified collagens from both constructs containing the integrin binding site showed significant adhesion of L929 cells that are known to possess the appropriate integrin receptor. C2C12 cells that lack any appropriate integrins did not bind. These data show that bacterial collagen-like sequences can be modified to act like natural extracellular matrix collagens by inserting one or more unique biological domains with defined function. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2189-2196, 2014. PMID:23913780
Peng, Yong Y; Stoichevska, Violet; Schacht, Kristin; Werkmeister, Jerome A; Ramshaw, John A M
Purified, recombinant M12 protein from Streptococcus pyogenes CS24 has recently been demonstrated to bind human immunoglobulin G3 (IgG3). The binding site for IgG has been localized to an internal peptide encoded by a PvuII fragment of the gene emm12. We have investigated the ability of an isolated recombinant M12 protein consisting of the peptide encoded by the PvuII fragment to bind various monoclonal human IgG3 myeloma proteins representing a number of both Caucasian and Oriental IgG3 Gm(allotypic) phenotypes. Of nine Caucasian IgG3 myeloma proteins, only two bound strongly to the recombinant M12 protein in enzyme-linked immunosorbent assays. The allotypic phenotypes of the reactive proteins were IgG3m(b+)(g-) and IgG3m(b-)(g+). No binding was seen for seven IgG3 myeloma proteins of Oriental origin with G3m(st+)(u-)(b+)(g-), G3m(st-)(u+)(b+)(g-), G3m(st-)(u+)(b-)(g+), and G3m(st-)(u-)(b-)(g+) phenotypes. The binding of human IgG3 to M12 protein seems to be related to features other than its Gm allotypic markers. Selective reactivity of IgG3 myeloma proteins with M12 protein may provide another way to subclassify human IgG3 molecules. The biological significance of the selective reactivity is not known.
Johansson, P J; Malone, C C; Williams, R C; Retnoningrum, D S; Cleary, P P
The Mga regulator of Streptococcus pyogenes directly activates the transcription of a core regulon that encodes virulence factors such as M protein (emm), C5a peptidase (scpA), and streptococcal inhibitor of complement (sic) by directly binding to a 45-bp binding site as determined by an electrophoretic mobility shift assay (EMSA) and DNase I protection. However, by comparing the nucleotide sequences of all established Mga binding sites, we found that they exhibit only 13.4% identity with no discernible symmetry. To determine the core nucleotides involved in functional Mga-DNA interactions, the M1T1 Pemm1 binding site was altered and screened for nucleotides important for DNA binding in vitro and for transcriptional activation using a plasmid-based luciferase reporter in vivo. Following this analysis, 34 nucleotides within the Pemm1 binding site that had an effect on Mga binding, Mga-dependent transcriptional activation, or both were identified. Of these critical nucleotides, guanines and cytosines within the major groove were disproportionately identified clustered at the 5? and 3? ends of the binding site and with runs of nonessential adenines between the critical nucleotides. On the basis of these results, a Pemm1 minimal binding site of 35 bp bound Mga at a level comparable to the level of binding of the larger 45-bp site. Comparison of Pemm with directed mutagenesis performed in the M1T1 Mga-regulated PscpA and Psic promoters, as well as methylation interference analysis of PscpA, establish that Mga binds to DNA in a promoter-specific manner.
Hause, Lara L.
Background Ralp3 is a transcriptional regulator present in a serotype specific fashion on the chromosome of the human pathogen Streptococcus pyogenes (group A streptococci, GAS). In serotypes harbouring the ralp3 gene either positive or negative effects on important metabolic and virulence genes involved in colonization and immune evasion in the human host were observed. A previous study revealed that deletion of ralp3 in a GAS M49 serotype significantly attenuated many virulence traits and caused metabolic disadvantages. This leads to two questions: (i) which kind of consequences could Ralp3 expression have in GAS serotypes naturally lacking this gene, and (ii) is Ralp3 actively lost during evolution in these serotypes. Methodology/Principal Findings We investigated the role of Ralp3 in GAS M2 and M6 pathogenesis. Both serotypes lack ralp3 on their chromosome. The heterologous expression of ralp3 in both serotypes resulted in reduced attachment to and internalization into the majority of tested epithelial cells. Both ralp3 expression strains showed a decreased ability to survive in human blood and exclusively M2::ralp3 showed decreased survival in human serum. Both mutants secreted more active SpeB in the supernatant, resulting in a higher activity compared to wild type strains. The respective M2 and M6 wild type strains outcompeted the ralp3 expression strains in direct metabolic competition assays. The phenotypic changes observed in the M2:ralp3 and M6:ralp3 were verified on the transcriptional level. Consistent with the virulence data, tested genes showed transcript level changes in the same direction. Conclusions/Significance Together these data suggest that Ralp3 can take over transcriptional control of virulence genes in serotypes lacking the ralp3 gene. Those serotypes most likely lost Ralp3 during evolution since obviously expression of this gene is disadvantageous for metabolism and pathogenesis.
Siemens, Nikolai; Kreikemeyer, Bernd
Background Small non-coding RNAs (sRNAs) have attracted attention as a new class of gene regulators in both eukaryotes and bacteria. Genome-wide screening methods have been successfully applied in Gram-negative bacteria to identify sRNA regulators. Many sRNAs are well characterized, including their target mRNAs and mode of action. In comparison, little is known about sRNAs in Gram-positive pathogens. In this study, we identified novel sRNAs in the exclusively human pathogen Streptococcus pyogenes M49 (Group A Streptococcus, GAS M49), employing a whole genome intergenic tiling array approach. GAS is an important pathogen that causes diseases ranging from mild superficial infections of the skin and mucous membranes of the naso-pharynx, to severe toxic and invasive diseases. Results We identified 55 putative sRNAs in GAS M49 that were expressed during growth. Of these, 42 were novel. Some of the newly-identified sRNAs belonged to one of the common non-coding RNA families described in the Rfam database. Comparison of the results of our screen with the outcome of two recently published bioinformatics tools showed a low level of overlap between putative sRNA genes. Previously, 40 potential sRNAs have been reported to be expressed in a GAS M1T1 serotype, as detected by a whole genome intergenic tiling array approach. Our screen detected 12 putative sRNA genes that were expressed in both strains. Twenty sRNA candidates appeared to be regulated in a medium-dependent fashion, while eight sRNA genes were regulated throughout growth in chemically defined medium. Expression of candidate genes was verified by reverse transcriptase-qPCR. For a subset of sRNAs, the transcriptional start was determined by 5? rapid amplification of cDNA ends-PCR (RACE-PCR) analysis. Conclusions In accord with the results of previous studies, we found little overlap between different screening methods, which underlines the fact that a comprehensive analysis of sRNAs expressed by a given organism requires the complementary use of different methods and the investigation of several environmental conditions. Despite a high conservation of sRNA genes within streptococci, the expression of sRNAs appears to be strain specific.
In the present study, 37 group A Streptococcus (GAS) strains belonging to 13 new emm sequence types identified among GAS strains randomly isolated in Brazil were characterized by using phenotypic and genotypic methods. The new types were designated st204, st211, st213, st809, st833, st854, st2904, st2911, st2917, st2926, st3757, st3765, and st6735. All isolates were susceptible to the antimicrobial agents tested, except to tetracycline. They all carried the speB gene, and 94.6% produced detectable SpeB. Most strains belonging to a given emm type had similar or highly related pulsed-field gel electrophoresis profiles that were distinct from profiles of strains of another type. The other characteristics were variable from isolate to isolate, although some associations were consistently found within some emm types. Unlike the other isolates, all type st213 isolates were speA positive and produced SpeA. Strains belonging to st3765 were T6 and opacity factor (OF) negative. Individual isolates within OF-positive emm types were associated with unique sof gene sequence types, while OF-negative isolates were sof negative by PCR. This report provides information on new emm sequence types first detected in GAS isolates from a geographic area not extensively surveyed. Such data can contribute to a better understanding of the local and global dynamics of GAS populations and of the epidemiological aspects of GAS infections occurring in tropical regions.
Teixeira, Lucia M.; Barros, Rosana R.; Castro, Angela Christina D.; Peralta, Jose Mauro; Da Gloria S. Carvalho, Maria; Talkington, Deborah F.; Vivoni, Adriana M.; Facklam, Richard R.; Beall, Bernard
The myosin cross-reactive antigen (MCRA) protein family is highly conserved among different bacterial species ranging from Gram-positive to Gram-negative bacteria. Besides their ubiquitous occurrence, knowledge about the biochemical and physiological function of MCRA proteins is scarce. Here, we show that MCRA protein from Streptococcus pyogenes M49 is a FAD enzyme, which acts as hydratase on (9Z)- and (12Z)-double bonds of C-16, C-18 non-esterified fatty acids. Products are 10-hydroxy and 10,13-dihydroxy fatty acids. Kinetic analysis suggests that FAD rather stabilizes the active conformation of the enzyme and is not directly involved in catalysis. Analysis of S. pyogenes M49 grown in the presence of either oleic or linoleic acid showed that 10-hydroxy and 10,13-dihydroxy derivatives were the only products. No further metabolism of these hydroxy fatty acids was detected. Deletion of the hydratase gene caused a 2-fold decrease in minimum inhibitory concentration against oleic acid but increased survival of the mutant strain in whole blood. Adherence and internalization properties to human keratinocytes were reduced in comparison with the wild type. Based on these results, we conclude that the previously identified MCRA protein can be classified as a FAD-containing double bond hydratase, within the carbon-oxygen lyase family, that plays a role in virulence of at least S. pyogenes M49.
Volkov, Anton; Liavonchanka, Alena; Kamneva, Olga; Fiedler, Tomas; Goebel, Cornelia; Kreikemeyer, Bernd; Feussner, Ivo
ABSTRACT Streptococcal surface dehydrogenase (SDH) (glyceraldehyde-3-phosphate dehydrogenase [GAPDH]) is an anchorless major multifunctional surface protein in group A Streptococcus (GAS) with the ability to bind important mammalian proteins, including plasmin(ogen). Although several biological properties of SDH are suggestive of its possible role in GAS virulence, its direct role in GAS pathogenesis has not been ascertained because it is essential for GAS survival. Thus, it has remained enigmatic as to “how and why” SDH/GAPDH is exported onto the bacterial surface. The present investigation highlights “why” SDH is exported onto the GAS surface. Differential microarray-based genome-wide transcript abundance analysis was carried out using a specific mutant, which was created by inserting a hydrophobic tail at the C-terminal end of SDH (M1-SDHHBtail) and thus preventing its exportation onto the GAS surface. This analysis revealed downregulation of the majority of genes involved in GAS virulence and genes belonging to carbohydrate and amino acid metabolism and upregulation of those related to lipid metabolism. The complete attenuation of this mutant for virulence in the mouse model and the decreased and increased virulence of the wild-type and mutant strains postcomplementation with SDHHBtail and SDH, respectively, indicated that the SDH surface export indeed regulates GAS virulence. M1-SDHHBtail also displayed unaltered growth patterns, increased intracellular ATP concentration and Hpr double phosphorylation, and significantly reduced pH tolerance, streptolysin S, and SpeB activities. These phenotypic and physiological changes observed in the mutant despite the unaltered expression levels of established transcriptional regulators further highlight the fact that SDH interfaces with many regulators and its surface exportation is essential for GAS virulence.
Jin, Hong; Agarwal, Shivangi; Agarwal, Shivani; Pancholi, Vijay
In the Streptococcus pyogenes M6 strain D471, an insertion of the conjugative transposon Tn916 into a region 2 kb upstream of the promoter of emm6 (the structural gene for the M protein) rendered the strain M negative (M. G. Caparon and J. R. Scott, Proc. Natl. Acad. Sci. USA 84:8677-8681, 1987). In the present work, we show that this insertion mutation, mry-1, is 244 bp upstream of an open reading frame encoding a protein we call Mry. This protein is visible on a gel after transcription and translation in vitro. We have developed a technique for complementation analysis in S. pyogenes and have used it to show that the wild-type mry gene is dominant to two mutant alleles. This dominance indicates that Mry acts in trans as a positive regulator of the emm6 gene. The translated DNA sequence of mry has two regions of similarity to the motif common to the receptor protein of two-component regulatory systems. In addition, the N terminus of Mry has two regions resembling a helix-turn-helix motif. Mry does not appear to be a global regulator of virulence determinants in the group A streptococcus because there is no effect of the mry-1 mutation on production of the hyaluronic acid capsule or streptokinase. Images
Perez-Casal, J; Caparon, M G; Scott, J R
Our multicenter nationwide surveillance data indicated that erythromycin (ERY) resistance among group A Streptococcus (GAS) isolates in Taiwan declined from 53.1% in 1998 and 2000 to 14.6% in 2002 and 2004 and 10.7% in 2006 to 2010 (P < 0.01). The present study aimed to assess the epidemiology of GAS in Taiwan and identify factors associated with ERY resistance. All 127 ERY-resistant (ERY(r)) isolates and 128 randomly selected ERY-susceptible (ERY(s)) isolates recovered from 1998 to 2010 were emm typed. ERY(r) isolates were also characterized by ERY resistance phenotype and mechanisms and pulsed-field gel electrophoresis (PFGE). Multilocus sequence typing was performed on selected ERY(r) isolates. The predominant emm types in ERY(r) isolates were emm22 (n = 33, 26.0%), emm12 (n = 24, 18.9%), emm4 (n = 21, 16.5%), and emm106 (n = 15, 11.8%). In ERY(s) isolates, emm12 (n = 27, 21.9%), emm1 (n = 18, 14.1%), emm106 (n = 16, 12.5%), and emm11 (n = 9, 7.1%) predominated. The most common ERY resistance phenotype was the M phenotype (resistant to macrolides) (70.9%), with all but one isolate carrying mef(A), followed by the constitutive macrolide-lincosamide-streptogramin B resistance (cMLSB) phenotype (26.8%), with isolates carrying erm(B) or erm(TR). ERY(r) isolates of the emm12-sequence type 36 (ST36) lineage with the cMLSB phenotype were mostly present before 2004, while those of the emm22-ST46 lineage with the M phenotype predominated in later years. Recovery from respiratory (throat swab) specimens was an independent factor associated with ERY resistance. emm1 and emm11 GAS isolates were significantly associated with ERY(s), while emm22 was detected only in ERY(r) GAS. In addition, emm106 isolates were prevalent among the abscess/pus isolates, whereas emm12 isolates were strongly associated with a respiratory (throat) origin. In addition to identifying factors associated with ERY resistance in GAS, our study provides helpful information on the changing GAS epidemiology in Taiwan. PMID:24478481
Huang, Chia-Ying; Lai, Jui-Fen; Huang, I-Wen; Chen, Pei-Chen; Wang, Hui-Ying; Shiau, Yih-Ru; Cheng, Ya-Wen; Hsieh, Li-Yun; Chang, Shan-Chwen; Lauderdale, Tsai-Ling Yang
Many pathogens express a surface protein that binds the human complement regulator factor H (FH), as first described for Streptococcus pyogenes and the antiphagocytic M6 protein. It is commonly assumed that FH recruited to an M protein enhances virulence by protecting the bacteria against complement deposition and phagocytosis, but the role of FH-binding in S. pyogenes pathogenesis has remained unclear and controversial. Here, we studied seven purified M proteins for ability to bind FH and found that FH binds to the M5, M6 and M18 proteins but not the M1, M3, M4 and M22 proteins. Extensive immunochemical analysis indicated that FH binds solely to the hypervariable region (HVR) of an M protein, suggesting that selection has favored the ability of certain HVRs to bind FH. These FH-binding HVRs could be studied as isolated polypeptides that retain ability to bind FH, implying that an FH-binding HVR represents a distinct ligand-binding domain. The isolated HVRs specifically interacted with FH among all human serum proteins, interacted with the same region in FH and showed species specificity, but exhibited little or no antigenic cross-reactivity. Although these findings suggested that FH recruited to an M protein promotes virulence, studies in transgenic mice did not demonstrate a role for bound FH during acute infection. Moreover, phagocytosis tests indicated that ability to bind FH is neither sufficient nor necessary for S. pyogenes to resist killing in whole human blood. While these data shed new light on the HVR of M proteins, they suggest that FH-binding may affect S. pyogenes virulence by mechanisms not assessed in currently used model systems.
Kristensen, Bodil M.; Olsen, John E.; Harris, Claire L.; Ufret-Vincenty, Rafael L.; Stalhammar-Carlemalm, Margaretha; Lindahl, Gunnar
The resurgence of severe invasive group A streptococcal infections in the 1980s is a typical example of the reemergence of an infectious disease. We found that this resurgence is a consequence of the diversification of particular strains of the bacteria. Among these strains is a highly virulent subclone of serotype M1T1 that has exhibited unusual epidemiologic features and virulence, unlike all other streptococcal strains. This clonal strain, commonly isolated from both noninvasive and invasive infection cases, is most frequently associated with severe invasive diseases. Because of its unusual prevalence, global spread, and increased virulence, we investigated the unique features that likely confer its unusual properties. In doing so, we found that the increased virulence of this clonal strain can be attributed to its diversification through phage mobilization and its ability to sense and adapt to different host environments; accordingly, the fittest members of this diverse bacterial community are selected to survive and invade host tissue.
Collagens are the major structural proteins in the extracellular matrix of animals and have a characteristic triple-helix structure that requires a (Gly-Xaa-Yaa)n sequence. Collagen has proven safe in a wide variety of medical products. For medical use, collagen is usually extracted from bovine tissue, but there has been a growing concern of transmissible diseases. Significant progress has been made in
A. Yoshizumi; S. J. Danon; O. Prokopenko; O. Mirochnitchenko; Z. Yu; M. Inouye; J. A. Werkmeister
A custom-designed microarray containing 220 virulence genes of Streptococcus pyogenes (group A Streptococcus [GAS]) was used to test group C Streptococcus dysgalactiae subsp. dysgalactiae (GCS) field strains causing bovine mastitis and group C or group G Streptococcus dysgalactiae subsp. equisimilis (GCS/GGS) isolates from human infections, with the latter being used for comparative purposes, for the presence of virulence genes. All bovine and all human isolates carried a fraction of the 220 genes (23% and 39%, respectively). The virulence genes encoding streptolysin S, glyceraldehyde-3-phosphate dehydrogenase, the plasminogen-binding M-like protein PAM, and the collagen-like protein SclB were detected in the majority of both bovine and human isolates (94 to 100%). Virulence factors, usually carried by human beta-hemolytic streptococcal pathogens, such as streptokinase, laminin-binding protein, and the C5a peptidase precursor, were detected in all human isolates but not in bovine isolates. Additionally, GAS bacteriophage-associated virulence genes encoding superantigens, DNase, and/or streptodornase were detected in bovine isolates (72%) but not in the human isolates. Determinants located in non-bacteriophage-related mobile elements, such as the gene encoding R28, were detected in all bovine and human isolates. Several virulence genes, including genes of bacteriophage origin, were shown to be expressed by reverse transcriptase PCR (RT-PCR). Phylogenetic analysis of superantigen gene sequences revealed a high level (>98%) of identity among genes of bovine GCS, of the horse pathogen Streptococcus equi subsp. equi, and of the human pathogen GAS. Our findings indicate that alpha-hemolytic bovine GCS, an important mastitis pathogen and considered to be a nonhuman pathogen, carries important virulence factors responsible for virulence and pathogenesis in humans.
Rato, Marcia G.; Nerlich, Andreas; Bergmann, Rene; Bexiga, Ricardo; Nunes, Sandro F.; Vilela, Cristina L.; Santos-Sanches, Ilda; Chhatwal, Gursharan S.
Streptococcus pyogenes (group A streptococcus [GAS]), a catalase-negative gram-positive bacterium, is aerotolerant and survives H2O2 exposures that kill many catalase-positive bacteria. The molecular basis of the H2O2 resistance is poorly known. Here, we demonstrate that serotype M49 GAS lacking the Rgg regulator is more resistant to H2O2 and also decomposes more H2O2 than the parental strain. Subgenomic transcriptional profiling and genome-integrated green fluorescent protein reporters showed that a bicistronic operon, a homolog of the Streptococcus mutans ahpCF operon, is transcriptionally up-regulated in the absence of Rgg. Phenotypic assays with ahpCF operon knockouts demonstrated that the gene products decompose H2O2 and protect GAS against peroxide stress. In a murine intraperitoneal-infection model, Rgg deficiency increased the virulence of GAS, although in an ahpCF-independent manner. Rgg-mediated repression of H2O2 resistance is divergent from the previously characterized peroxide resistance repressor PerR. Moreover, Rgg-mediated repression of H2O2 resistance is inducible by cellular stresses of diverse natures—ethanol, organic hydroperoxide, and H2O2. Rgg is thus identified as a novel sensoregulator of streptococcal H2O2 resistance with potential implications for the virulence of the catalase-negative GAS.
Pulliainen, Arto Tapio; Hytonen, Jukka; Haataja, Sauli; Finne, Jukka
For years it has been clear that plasminogen from different sources and enolase from different sources interact strongly. What is less clear is the nature of the structures required for them to interact. This work examines the interaction between canine plasminogen (dPgn) and Streptococcus pyogenes enolase (Str enolase) using analytical ultracentrifugation (AUC), surface plasmon resonance (SPR), fluorescence polarization, dynamic light scattering (DLS), isothermal titration calorimetry (ITC), and simple pull-down reactions. Overall, our data indicate that a non-native structure of the octameric Str enolase (monomers or multimers) is an important determinant of its surface-mediated interaction with host plasminogen. Interestingly, a non-native structure of plasminogen is capable of interacting with native enolase. As far as we can tell, the native structures resist forming stable mixed complexes.
Hancock, Mark A.
Bacteriophage T12, the prototypic bacteriophage of Streptococcus pyogenes carrying the erythrogenic toxin A gene (speA), integrates into the bacterial chromosome at a gene for a serine tRNA (W. M. McShan, Y.-F. Tang, and J. J. Ferretti, Mol. Microbiol. 23:719-728, 1997). This phage is a member of a group of related temperate phages, and we show here that not all speA-carrying phages in this group use the same attachment site for integration into the bacterial chromosome. Additionally, other phages in the group use the same serine tRNA gene attachment site as phage T12 and yet do not carry speA. The evidence suggests that recombination between phage genomes has been an important means of generating diversity and disseminating virulence-associated genes like speA.
McShan, W M; Ferretti, J J
Compounds able to interfere with amino acid biosynthesis have the potential to inhibit cell growth. In both prokaryotic and eukaryotic microorganisms, unless an ornithine cyclodeaminase is present, the activity of ?1-pyrroline-5-carboxylate (P5C) reductase is mandatory to proline production, and the enzyme inhibition should result in amino acid starvation, blocking in turn protein synthesis. The ability of some substituted derivatives of aminomethylenebisphosphonic acid and its analogues to interfere with the activity of the enzyme from the human pathogen Streptococcus pyogenes was investigated. Several compounds were able to suppress activity in the micromolar range of concentrations, with a mechanism of uncompetitive type with respect to the substrate P5C and non-competitive with respect to the electron donor NAD(P)H. The actual occurrence of enzyme inhibition in vivo was supported by the effects of the most active derivatives upon bacterial growth and free amino acid content. PMID:21744012
Forlani, Giuseppe; Petrollino, Davide; Fusetti, Massimo; Romanini, Letizia; Nocek, Bogus?aw; Joachimiak, Andrzej; Berlicki, Lukasz; Kafarski, Pawe?
For a pathogen such as Streptococcus pyogenes, ecological success is determined by its ability to sense the environment and mount an appropriate adaptive transcriptional response. Thus, determining conditions for analyses of gene expression in vitro that are representative of the in vivo environment is critical for understanding the contributions of transcriptional response pathways to pathogenesis. In this study, we determined that the gene encoding the SpeB cysteine protease is up-regulated over the course of infection in a murine soft-tissue model. Conditions were identified, including growth phase, acidic pH, and an NaCl concentration of <0.1 M, that were required for expression of speB in vitro. Analysis of global expression profiles in response to these conditions in vitro identified a set of coregulated genes whose expression patterns showed a significant correlation with that of speB when examined during infection of murine soft tissues. This analysis revealed that a culture medium that promotes high levels of SpeB expression in vitro produced an expression profile that showed significant correlation to the profile observed in vivo. Taken together, these studies establish culture conditions that mimic in vivo expression patterns; that growth phase, pH, and NaCl may mimic relevant cues sensed by S. pyogenes during infection; and that identification of other environmental cues that alter expression of speB in vitro may provide insight into the signals that direct global patterns of gene expression in vivo.
Loughman, Jennifer A.; Caparon, Michael
Summary Objective To compare the prevalence, phenotypes, and genes responsible for erythromycin resistance among Streptococcus pyogenes isolates from Mexico and the USA. Methods Eighty-nine invasive and 378 non-invasive isolates from Mexico, plus 148 invasive, 21 non-invasive, and five unclassified isolates from the USA were studied. Susceptibilities to penicillin, erythromycin, clindamycin, ceftriaxone, and vancomycin were evaluated according to Clinical and Laboratory Standards Institute (CLSI) standards. Phenotypes of erythromycin resistance were identified by triple disk test, and screening for mefA, ermTR, and ermB genes was carried out by PCR. Results All isolates were susceptible to penicillin, ceftriaxone, and vancomycin. Erythromycin resistance was found in 4.9% of Mexican strains and 5.2% of USA strains. Phenotypes in Mexican strains were 95% M and 5% cMLS; in strains from the USA, phenotypes were 33.3% iMLS, 33.3% iMLS-D, and 33.3% M. Erythromycin resistance genes in strains from Mexico were mefA (95%) and ermB (5%); USA strains harbored ermTR (56%), mefA (33%), and none (11%). In Mexico, all erythromycin-resistant strains were non-invasive, whereas 89% of strains from the USA were invasive. Conclusions Erythromycin resistance continues to exist at low levels in both Mexico and the USA, although the genetic mechanisms responsible differ between the two nations. These genetic differences may be related to the invasive character of the S. pyogenes isolated.
Villasenor-Sierra, Alberto; Katahira, Eva; Jaramillo-Valdivia, Abril N.; de los Angeles Barajas-Garcia, Maria; Bryant, Amy; Morfin-Otero, Rayo; Marquez-Diaz, Francisco; Tinoco, Juan Carlos; Sanchez-Corona, Jose; Stevens, Dennis L.
We recently showed that a prophage-like Streptococcus pyogenes chromosomal island (SpyCI) controls DNA mismatch repair and other repair functions in M1 genome strain SF370 by dynamic excision and reintegration into the 5? end of mutL in response to growth, causing the cell to alternate between a wild type and mutator phenotype. Nine of the 16 completed S. pyogenes genomes contain related SpyCI integrated into the identical attachment site in mutL, and in this study we examined a number of these strains to determine whether they also had a mutator phenotype as in SF370. With the exception of M5 genome strain Manfredo, all demonstrated a mutator phenotype as compared to SpyCI-free strain NZ131. The integrase gene (int) in the SpyCIM5 contains a deletion that rendered it inactive, and this deletion predicts that Manfredo would have a pronounced mutator phenotype. Remarkably, this was found not to be the case, but rather a cryptic promoter within the int ORF was identified that ensured constitutive expression of mutL and the downstream genes encoded on the same mRNA, providing a striking example of rescue of gene function following decay of a mobile genetic element. The frequent occurrence of SpyCI in the group A streptococci may facilitate bacterial survival by conferring an inducible mutator phenotype that promotes adaptation in the face of environmental challenges or host immunity.
Scott, Julie; Nguyen, Scott V.; King, Catherine J.; Hendrickson, Christina; McShan, W. Michael
Purulent disease of the uterus develops in 40% of dairy cows after parturition, when the epithelium of the endometrium is disrupted to expose the underlying stroma to bacteria. The severity of endometrial pathology is associated with isolation of Trueperella pyogenes. In the present study, T. pyogenes alone caused uterine disease when infused into the uterus of cattle where the endometrial epithelium was disrupted. The bacterium secretes a cholesterol-dependent cytolysin, pyolysin (PLO), and the plo gene was identical and the plo gene promoter was highly similar amongst 12 clinical isolates of T. pyogenes. Bacteria-free filtrates of the T. pyogenes cultures caused hemolysis and endometrial cytolysis, and PLO was the main cytolytic agent, because addition of anti-PLO antibody prevented cytolysis. Similarly, a plo-deletion T. pyogenes mutant did not cause hemolysis or endometrial cytolysis. Endometrial stromal cells were notably more sensitive to PLO-mediated cytolysis than epithelial or immune cells. Stromal cells also contained more cholesterol than epithelial cells, and reducing stromal cell cholesterol content using cyclodextrins protected against PLO. Although T. pyogenes or plo-deletion T. pyogenes stimulated accumulation of inflammatory mediators, such as IL-1beta, IL-6, and IL-8, from endometrium, PLO did not stimulate inflammatory responses by endometrial or hematopoietic cells, or in vitro organ cultures of endometrium. The marked sensitivity of stromal cells to PLO-mediated cytolysis provides an explanation for how T. pyogenes acts as an opportunistic pathogen to cause pathology of the endometrium once the protective epithelium is lost after parturition. PMID:24478394
Amos, Matthew R; Healey, Gareth D; Goldstone, Robert J; Mahan, Suman M; Düvel, Anna; Schuberth, Hans-Joachim; Sandra, Olivier; Zieger, Peter; Dieuzy-Labaye, Isabelle; Smith, David G E; Sheldon, Iain Martin
A stepwise computational approach using three layers of publicly available software was found to effectively identify DNA signatures for Streptococcus pyogenes. PCR testing validated that 9 out of 15 signature-derived primer sets could detect as low as 5 fg of target DNA with high specificity. The selected signature-derived primer sets were successfully evaluated against all 23 clinical isolates. The approach is readily applicable for designing molecular assays for rapid detection and characterization of various pathogenic bacteria.
Hung, Guo-Chiuan; Nagamine, Kenjiro; Li, Bingjie
Macrophages play a crucial role in the innate immune response against the human pathogen Streptococcus pyogenes, yet the innate immune response against the bacterium is poorly characterized. In the present study, we show that caspase-1 activation and IL-1beta secretion were induced by live, but not killed, S. pyogenes, and required expression of the pore-forming toxin streptolysin O. Using macrophages deficient in inflammasome components, we found that both NLR family pyrin domain-containing 3 (Nlrp3) and apoptosis-associated speck-like protein (Asc) were crucial for caspase-1 activation and IL-1beta secretion, but dispensable for pro-IL-1beta induction, in response to S. pyogenes infection. Conversely, macrophages deficient in the essential TLR adaptors Myd88 and Trif showed normal activation of caspase-1, but impaired induction of pro-IL-1beta and secretion of IL-1beta. Notably, activation of caspase-1 by TLR2 and TLR4 ligands in the presence of streptolysin O required Myd88/Trif, whereas that induced by S. pyogenes was blocked by inhibition of NF-kappaB. Unlike activation of the Nlrp3 inflammasome by TLR ligands, the induction of caspase-1 activation by S. pyogenes did not require exogenous ATP or the P2X7R. In vivo experiments revealed that Nlrp3 was critical for the production of IL-1beta but was not important for survival in a mouse model of S. pyogenes peritoneal infection. These results indicate that caspase-1 activation in response to S. pyogenes infection requires NF-kappaB and the virulence factor streptolysin O, but proceeds independently of P2X7R and TLR signaling. PMID:19812205
Harder, Jürgen; Franchi, Luigi; Muñoz-Planillo, Raúl; Park, Jong-Hwan; Reimer, Thornik; Núñez, Gabriel
Studies directed at vaccine development and mucosal immunity against Streptococcus pyogenes would benefit from the availability of live attenuated strains. Our approach for production of candidate live attenuated strains was to identify mutations that did not alter growth in vitro and did not alter the overall complement of virulence factors produced but did result in reduced levels of expression of multiple secreted virulence factors. A global reduction but not elimination of expression would likely lead to attenuation while maximizing the number of antigenic targets available for stimulation of immunity. Adaptation of Tn5-based transposome mutagenesis to S. pyogenes with initial screening for reduced expression of the SpeB protease resulted in identification of mutations in gidA, which encodes an enzyme involved in tRNA modification. Reduced SpeB expression was due to delayed onset of speB transcription resulting from reduced translation efficiency of the message for RopB, a transcriptional activator. Overall, GidA? mutants had a nearly normal global transcription profile but expressed significantly reduced levels of multiple virulence factors due to impaired translation efficiencies. A translation defect was supported by the observation that mutants lacking MnmE, which functions in the same tRNA modification pathway as GidA, phenocopied GidA deficiency. The mutants stimulated a cytokine response in cultured macrophages identical to that in the wild type, with the exception of reduced levels of tumor necrosis factor alpha and interleukin-23. Significantly, GidA? mutants were highly attenuated in the murine ulcer model of soft tissue infection. These characteristics suggest that GidA pathway tRNA modification mutants are attractive candidates for further evaluation as live attenuated strains.
Cho, Kyu Hong; Caparon, Michael G.
Small cyclic nucleotide derivatives are employed as second messengers by both prokaryotes and eukaryotes to regulate diverse cellular processes responding to various signals. In bacteria, c-di-AMP has been discovered most recently, and some Gram-positive pathogens including S. pyogenes use this cyclic nucleotide derivative as a second messenger instead of c-di-GMP, a well-studied important bacterial second messenger. GdpP, c-di-AMP phosphodiesterase, is responsible for degrading c-di-AMP inside cells, and the cellular role of GdpP in S. pyogenes has not been examined yet. To test the cellular role of GdpP, we created a strain with a nonpolar inframe deletion of the gdpP gene, and examined the properties of the strain including virulence. From this study, we demonstrated that GdpP influences the biogenesis of SpeB, the major secreted cysteine protease, at a post-translational level, susceptibility to the beta lactam antibiotic ampicillin, and is necessary for full virulence in a murine subcutaneous infection model.
Cho, Kyu Hong; Kang, Song Ok
Streptococcus pyogenes (group A streptococcus; GAS) is a leading human pathogen associated with a diverse array of mucosal and systemic infections. Vaccination with J8, a conserved region synthetic peptide derived from the M-protein of GAS and containing only 12 amino acids from GAS, when conjugated to DT, has been shown to protect mice against a lethal GAS challenge. Protection has been previously shown to be antibody-mediated. J8 does not contain a dominant GAS-specific T-cell epitope. The current study examined long-term antibody memory and dissected the role of B and T-cells. Our results demonstrated that vaccination generates specific memory B-cells and long-lasting antibody responses. The memory B-cell response can be activated following boost with antigen or limiting numbers of whole bacteria. We further show that these memory responses protect against systemic infection with GAS. T-cell help is required for activation of memory B-cells but can be provided by naïve T-cells responding directly to GAS at the time of infection. Thus, individuals whose T-cells do not recognize the short synthetic peptide in the vaccine will be able to generate a protective and rapid memory antibody response at the time of infection. These studies significantly strengthen previous findings, which showed that protection by the J8-DT vaccine is antibody-mediated and suggest that in vaccine design for other organisms the source of T-cell help for antibody responses need not be limited to sequences from the organism itself.
Pandey, Manisha; Wykes, Michelle N; Hartas, Jon; Good, Michael F; Batzloff, Michael R
Cell division and cell wall synthesis are closely linked complex phenomena and play a crucial role in the maintenance and regulation of bacterial virulence. Eukaryotic-type Ser/Thr kinases reported in prokaryotes, including that in group A Streptococcus (GAS) (Streptococcus pyogenes Ser/Thr kinase (SP-STK)), regulate cell division, growth, and virulence. The mechanism of this regulation is, however, unknown. In this study, we demonstrated that SP-STK-controlled cell division is mediated under the positive regulation of secretory protein that possesses a cysteine and histidine-dependent aminohydrolases/peptidases (CHAP) domain with functionally active cell wall hydrolase activity (henceforth named as CdhA (CHAP-domain-containing and chain-forming cell wall hydrolase). Deletion of the CdhA-encoding gene resulted in severe cell division and growth defects in GAS mutants. The mutant expressing the truncated CdhA (devoid of the CHAP domain), although displayed no such defects, it became attenuated for virulence in mice and highly susceptible to cell wall-acting antibiotics, as observed for the mutant lacking CdhA. When CdhA was overexpressed in the wild-type GAS as well as in heterologous strains, Escherichia coli and Staphylococcus aureus, we observed a distinct increase in bacterial chain length. Our data reveal that CdhA is a multifunctional protein with a major function of the N-terminal region as a cell division plane-recognizing domain and that of the C-terminal CHAP domain as a virulence-regulating domain. CdhA is thus an important therapeutic target.
Pancholi, Vijay; Boel, Gregory; Jin, Hong
Cysteine protease SpeB is secreted from Streptococcus pyogenes and has been studied as a potential virulence factor since its identification almost 70 years ago. Here, we report the crystal structures of apo mature SpeB to 1.06 ? resolution as well as complexes with the general cysteine protease inhibitor trans-epoxysuccinyl-l-leucylamido(4-guanidino)butane and a novel substrate mimetic peptide inhibitor. These structures uncover conformational changes associated with maturation of SpeB from the inactive zymogen to its active form and identify the residues required for substrate binding. With the use of a newly developed fluorogenic tripeptide substrate to measure SpeB activity, we determined IC50 values for trans-epoxysuccinyl-l-leucylamido(4-guanidino)butane and our new peptide inhibitor and the effects of mutations within the C-terminal active site loop. The structures and mutational analysis suggest that the conformational movements of the glycine-rich C-terminal loop are important for the recognition and recruitment of biological substrates and release of hydrolyzed products.
Gonzalez-Paez, Gonzalo E.; Wolan, Dennis W.
A range of bacteria have been shown to contain collagen-like sequences that form triple-helical structures. Some of these proteins have been shown to form triple-helical motifs that are stable around body temperature without the inclusion of hydroxyproline or other secondary modifications to the protein sequence. This makes these collagen-like proteins particularly suitable for recombinant production as only a single gene product and no additional enzyme needs to be expressed. In the present study, we have examined the cytotoxicity and immunogenicity of the collagen-like domain from Streptococcus pyogenes Scl2 protein. These data show that the purified, recombinant collagen-like protein is not cytotoxic to fibroblasts and does not illicit an immune response in SJL/J and Arc mice. The freeze dried protein can be stabilised by glutaraldehyde cross-linking giving a material that is stable at >37°C and which supports cell attachment while not causing loss of viability. These data suggest that bacterial collagen-like proteins, which can be modified to include specific functional domains, could be a useful material for medical applications and as a scaffold for tissue engineering.
Peng, Yong Y.; Yoshizumi, Ayumi; Danon, Stephen J.; Glattauer, Veronica; Prokopenko, Olga; Mirochnitchenko, Oleg; Yu, Zhuoxin; Inouye, Masayori; Werkmeister, Jerome A.; Brodsky, Barbara; Ramshaw, John A.M.
A range of bacteria have been shown to contain collagen-like sequences that form triple-helical structures. Some of these proteins have been shown to form triple-helical motifs that are stable around body temperature without the inclusion of hydroxyproline or other secondary modifications to the protein sequence. This makes these collagen-like proteins particularly suitable for recombinant production as only a single gene product and no additional enzyme needs to be expressed. In the present study, we have examined the cytotoxicity and immunogenicity of the collagen-like domain from Streptococcus pyogenes Scl2 protein. These data show that the purified, recombinant collagen-like protein is not cytotoxic to fibroblasts and does not elicit an immune response in SJL/J and Arc mice. The freeze dried protein can be stabilised by glutaraldehyde cross-linking giving a material that is stable at >37 degrees C and which supports cell attachment while not causing loss of viability. These data suggest that bacterial collagen-like proteins, which can be modified to include specific functional domains, could be a useful material for medical applications and as a scaffold for tissue engineering. PMID:20056274
Peng, Yong Y; Yoshizumi, Ayumi; Danon, Stephen J; Glattauer, Veronica; Prokopenko, Olga; Mirochnitchenko, Oleg; Yu, Zhuoxin; Inouye, Masayori; Werkmeister, Jerome A; Brodsky, Barbara; Ramshaw, John A M
Regulation of oxidative stress responses by the peroxide stress regulator (PerR) is critical for the in vivo fitness and virulence of group A Streptococcus. To elucidate the molecular mechanism of DNA binding, peroxide sensing, and gene regulation by PerR, we performed biochemical and structural characterization of PerR. Sequence-specific DNA binding by PerR does not require regulatory metal occupancy. However, metal binding promotes higher affinity PerR-DNA interactions. PerR metallated with iron directly senses peroxide stress and dissociates from operator sequences. The crystal structure revealed that PerR exists as a homodimer with two metal-binding sites per subunit as follows: a structural zinc site and a regulatory metal site that is occupied in the crystals by nickel. The regulatory metal-binding site in PerR involves a previously unobserved HXH motif located in its unique N-terminal extension. Mutational analysis of the regulatory site showed that the PerR metal ligands are involved in regulatory metal binding, and integrity of this site is critical for group A Streptococcus virulence. Interestingly, the metal-binding HXH motif is not present in the structurally characterized members of ferric uptake regulator (Fur) family but is fully conserved among PerR from the genus Streptococcus. Thus, it is likely that the PerR orthologs from streptococci share a common mechanism of metal binding, peroxide sensing, and gene regulation that is different from that of well characterized PerR from Bacillus subtilis. Together, our findings provide key insights into the peroxide sensing and regulation of the oxidative stress-adaptive responses by the streptococcal subfamily of PerR.
Makthal, Nishanth; Rastegari, Sheila; Sanson, Misu; Ma, Zhen; Olsen, Randall J.; Helmann, John D.; Musser, James M.; Kumaraswami, Muthiah
Preliminary pediatric clinical evaluation of the oral probiotic Streptococcus salivarius K12 in preventing recurrent pharyngitis and/or tonsillitis caused by Streptococcus pyogenes and recurrent acute otitis media
Background The oral probiotic Streptococcus salivarius K12 has been shown clearly to antagonize the growth of Streptococcus pyogenes, the most important bacterial cause of pharyngeal infections in humans, by releasing two bacteriocins named salivaricin A2 and salivaricin B. Unpublished observations indicate that it can also antagonize the growth of other bacteria involved in acute otitis media. Because of its ability to colonize the oral cavity and its safety profile, we have tested its efficacy in reducing the incidence of streptococcal pharyngitis and/or tonsillitis and episodes of acute otitis media. Methods We enrolled 82 children, including 65 with and 17 without a recent diagnosis of recurrent oral streptococcal pathology. Of those with recurrent pathology, 45 were treated daily for 90 days with an oral slow-release tablet containing five billion colony-forming units of S. salivarius K12 (Bactoblis®), and the remaining 20 served as an untreated control group. The 17 children without a recent diagnosis of recurrent oral pathology were used as an additional control group. After 90 days of treatment, a 6-month follow-up period without treatment was included to evaluate a possible persistent protective role for the previously administered product. Results The 41 children who completed the 90-day course of Bactoblis showed a reduction in their episodes of streptococcal pharyngeal infection (about 90%) and/or acute otitis media (about 40%), calculated by comparing infection rates in the previous year. The 90-day treatment also reduced the reported incidence of pharyngeal and ear infections by about 65% in the 6-month follow-up period during which the product was not administered. Subjects tolerated the product well, with no side effects or dropouts reported. Conclusion Prophylactic administration of S. salivarius K12 to children with a history of recurrent oral streptococcal pathology reduced episodes of streptococcal pharyngeal infections and/or tonsillitis as well as episodes of acute otitis media.
Di Pierro, Francesco; Donato, Guido; Fomia, Federico; Adami, Teresa; Careddu, Domenico; Cassandro, Claudia; Albera, Roberto
Streptococcus pyogenes, or group A Streptococcus, is one of the most frequent causes of pharyngitis and skin infections in humans. Many virulence mechanisms have been suggested to be involved in the infectious process. Among them is the binding to the bacterial cell surface of the complement regulatory proteins factor H, factor H-like protein 1 (FHL-1), and C4b-binding protein. Previous studies indicate that binding of these three regulators to the streptococcal cell involves the M protein encoded by the emm gene. M-type 18 strains are prevalent among clinical isolates and have been shown to interact with all three complement regulators simultaneously. Using isogenic strains lacking expression of the Emm18 or the Enn18 proteins, we demonstrate in this study that, in contradistinction to previously described S. pyogenes strains, M18 strains bind the complement regulators factor H, FHL-1, and C4b-binding protein through two distinct cell surface proteins. Factor H and FHL-1 bind to the Emm18 protein, while C4BP binds to the Enn18 protein. We propose that expression of two distinct surface structures that bind complement regulatory proteins represents a unique adaptation of M18 strains that enhances their resistance to opsonization by human plasma and increases survival of this particular S. pyogenes strain in the human host. These new findings illustrate that S. pyogenes has evolved diverse mechanisms for recruitment of complement regulatory proteins to the bacterial surface to evade immune clearance in the human host. PMID:15557185
Pérez-Caballero, David; García-Laorden, Isabel; Cortés, Guadalupe; Wessels, Michael R; de Córdoba, Santiago Rodríguez; Albertí, Sebastián
Microbial pathogens often exploit human complement regulatory proteins such as factor H (FH) and factor H-like protein 1 (FHL-1) for immune evasion. Fba is an FH and FHL-1 binding protein expressed on the surface of the human pathogenic bacterium Streptococcus pyogenes, a common agent of pharyngeal, skin, and soft-tissue infections. Fba has been shown to contribute to phagocytosis resistance, intracellular invasion, and virulence in mice. Here, we look at the role of Fba in recruitment of FH and FHL-1 by five serotype M1 isolates of streptococci. Inactivation of fba greatly inhibited binding of FH and FHL-1 by all isolates, indicating that Fba is a major FH and FHL-1 binding factor of serotype M1 streptococci. For three isolates, FH binding was significantly reduced in stationary-phase cultures and correlated with high levels of protease activity and SpeB (an extracellular cysteine protease) protein in culture supernatants. Analysis of a speB mutant confirmed that SpeB accounts for the loss of Fba from the cell surface, suggesting that the protease may modulate FH and FHL-1 recruitment during infection. Comparisons of fba DNA sequences revealed that the FH and FHL-1 binding site in Fba is conserved among the M1 isolates. Although the ligand binding site is not strictly conserved in Fba from a serotype M49 isolate, the M49 Fba protein was found to bind both FH and FHL-1. Collectively, these data indicate that binding of FH and FHL-1 is a conserved function of Fba while modulation of Fba function by SpeB is variable. PMID:15784545
Wei, Lin; Pandiripally, Vinod; Gregory, Eugene; Clymer, Micaya; Cue, David
One hundred and seven clinical isolates of Streptococcus pyogenes, 80 susceptible to macrolides and 27 resistant to erythromycin A (MIC >0.5 ?g/ml), were examined. The erythromycin A-lincomycin double-disk test assigned 7 resistant strains to the M-phenotype, 8 to the inducible macrolide, lincosamide, and streptogramin B resistance (iMLSB) phenotype, and 12 to the constitutive MLSB resistance (cMLSB) phenotype. MICs of erythromycin A, clarithromycin, azithromycin, roxithromycin, and clindamycin were determined by a broth microdilution method. MICs of telithromycin were determined by three different methods (broth microdilution, agar dilution, and E-test methods) in an ambient air atmosphere and in a 5 to 6% CO2 atmosphere. Erythromycin A resistance genes were investigated by PCR in the 27 erythromycin A-resistant isolates. MICs of erythromycin A and clindamycin showed six groups of resistant strains, groups A to F. iMLSB strains (A, B, and D groups) are characterized by two distinct patterns of resistance correlated with genotypic results. A- and B-group strains were moderately resistant to 14- and 15-membered ring macrolides and highly susceptible to telithromycin. All A- and B-group isolates harbored erm TR gene, D-group strains, highly resistant to macrolides and intermediately resistant to telithromycin (MICs, 1 to 16 ?g/ml), were all characterized by having the ermB gene. All M-phenotype isolates (C group), resistant to 14- and 15-membered ring macrolides and susceptible to clindamycin and telithromycin, harbored the mefA gene. All cMLSB strains (E and F groups) with high level of resistance to macrolides, lincosamide, and telithromycin had the ermB gene. The effect of 5 to 6% CO2 was remarkable on resistant strains, by increasing MICs of telithromycin from 1 to 6 twofold dilutions against D-E- and F-group isolates.
Bemer-Melchior, Pascale; Juvin, Marie-Emmanuelle; Tassin, Sandrine; Bryskier, Andre; Schito, Gian Carlo; Drugeon, Henri-B.
The main virulence factor of group A streptococcus (GAS), M protein, binds plasma complement regulators factor H (FH) and FH-like protein 1 (FHL-1) leading to decreased opsonization. The M protein binding site on FH is within domain 7 in which also the age-related macular degeneration (AMD)-associated polymorphism Y402H is located. We studied if FH allotypes 402H and 402Y have different binding affinities to GAS. Plasma-derived FH allotype 402H and its recombinant fragment FH5-7(402H) showed decreased binding to several GAS strains. Growth of GAS in human blood taken from FH(402H) homozygous individuals was decreased when compared with blood taken from FH(402Y) homozygous individuals. The effect of the allotype 402H can be explained by combining the previous M protein mutagenesis data and the recently published crystal structure of FH6-8. In conclusion the data indicate that the AMD-associated allotype 402H leads to diminished binding of FH to GAS and increased opsonophagocytosis of the bacteria in blood. These results suggest that the homozygous presence of the allele 402H could be associated with decreased risk for severe GAS infections offering an explanation for the high frequency of the allele despite its association with visual impairment. PMID:18627465
Haapasalo, Karita; Jarva, Hanna; Siljander, Tuula; Tewodros, Wezenet; Vuopio-Varkila, Jaana; Jokiranta, T Sakari
This investigation illustrates an important property of eukaryote-type serine/threonine phosphatase (SP-STP) of group A Streptococcus (GAS) in causing programmed cell death of human pharyngeal cells. The secretory nature of SP-STP, its elevated expression in the intracellular GAS, and the ability of wild-type GAS but not the GAS mutant devoid of SP-STP to cause apoptosis of the host cell both in vitro and in vivo suggest that GAS deploys SP-STP as an important virulence determinant to exploit host cell machinery for its own advantage during infection. The exogenously added SP-STP is able to enter the cytoplasm and subsequently traverses into the nucleus in a temporal fashion to cause apoptosis of the pharyngeal cells. The programmed cell death induced by SP-STP, which requires active transcription and de novo protein synthesis, is also caspase-dependent. Furthermore, the entry of SP-STP into the cytoplasm is dependent on its secondary structure as the catalytically inactive SP-STP with an altered structure is unable to internalize and cause apoptosis. The ectopically expressed wild-type SP-STP was found to be in the nucleus and conferred apoptosis of Detroit 562 pharyngeal cells. However, the catalytically inactive SP-STP was unable to cause apoptosis even when intracellularly expressed. The ability of SP-STP to activate pro-apoptotic signaling cascades both in the cytoplasm and in the nucleus resulted in mitochondrial dysfunctioning and perturbation in the phosphorylation status of histones in the nucleus. SP-STP thus not only functions as a virulence regulator but also as an important factor responsible for host-related pathogenesis.
Agarwal, Shivani; Agarwal, Shivangi; Jin, Hong; Pancholi, Preeti; Pancholi, Vijay
The streptokinase (SK) is emerging as an important thrombolytic therapy agent in the treatment of patients suffering from cardiovascular diseases. We reported highly effective renaturation of a SK from S. pyogeness DT7 overexpressed in E. coli, purification, and biochemical characterization. A gene coding for the SK was cloned from S. pyogeness DT7. Because accumulation of active SK is toxic to the host cells, we have expressed it in the form of inclusion bodies. The mature protein was overexpressed in E. coli BL21 DE3/pESK under the control of the strong promoter tac induced by IPTG with a level of 60% of the total cell proteins. The activity of the rSK, renatured in phosphate buffer supplemented with Triton X-100 and glycerol, was covered with up to 41 folds of its initial activity. The purified of protein was identified with MALDI-TOF mass spectrometry through four peptide fragments, which showed 100% identification to the corresponding peptides of the putative SK from GenBank. Due to overexpression and highly effective renaturation of large amounts of inclusion bodies, the recombinant E. coli BL21 DE3/pESK system could be potentially applied for large-scale production of SK used in the therapy of acute myocardial infarction. PMID:24883307
Nguyen, Sy Le Thanh; Quyen, Dinh Thi; Vu, Hong Diep
The streptokinase (SK) is emerging as an important thrombolytic therapy agent in the treatment of patients suffering from cardiovascular diseases. We reported highly effective renaturation of a SK from S. pyogeness DT7 overexpressed in E. coli, purification, and biochemical characterization. A gene coding for the SK was cloned from S. pyogeness DT7. Because accumulation of active SK is toxic to the host cells, we have expressed it in the form of inclusion bodies. The mature protein was overexpressed in E. coli BL21 DE3/pESK under the control of the strong promoter tac induced by IPTG with a level of 60% of the total cell proteins. The activity of the rSK, renatured in phosphate buffer supplemented with Triton X-100 and glycerol, was covered with up to 41 folds of its initial activity. The purified of protein was identified with MALDI-TOF mass spectrometry through four peptide fragments, which showed 100% identification to the corresponding peptides of the putative SK from GenBank. Due to overexpression and highly effective renaturation of large amounts of inclusion bodies, the recombinant E. coli BL21 DE3/pESK system could be potentially applied for large-scale production of SK used in the therapy of acute myocardial infarction.
Nguyen, Sy Le Thanh; Quyen, Dinh Thi; Vu, Hong Diep
Sixty-three recent Italian clinical isolates of Streptococcus pyogenes resistant to both erythromycin (MICs ? 1 ?g/ml) and tetracycline (MICs ? 8 ?g/ml) were genotyped for macrolide and tetracycline resistance genes. We found 19 isolates carrying the mef(A) and the tet(O) genes; 25 isolates carrying the erm(A) and tet(O) genes; and 2 isolates carrying the erm(A), tet(M), and tet(O) genes. The resistance of all erm(A)-containing isolates was inducible, but the isolates could be divided into two groups on the basis of erythromycin MICs of either >128 or 1 to 4 ?g/ml. The remaining 17 isolates included 15 isolates carrying the erm(B) gene and 2 isolates carrying both the erm(B) and the mef(A) genes, with all 17 carrying the tet(M) gene. Of these, 12 carried Tn916-Tn1545-like conjugative transposons. Conjugal transfer experiments demonstrated that the tet(O) gene moved with and without the erm(A) gene and with the mef(A) gene. These studies, together with the results of pulsed-field gel electrophoresis experiments and hybridization assays with DNA probes specific for the tet(O), erm(A), and mef(A) genes, suggested a linkage of tet(O) with either erm(A) or mef(A) in erythromycin- and tetracycline-resistant S. pyogenes isolates. By amplification and sequencing experiments, we detected the tet(O) gene ca. 5.5 kb upstream from the mef(A) gene. This is the first report demonstrating the presence of the tet(O) gene in S. pyogenes and showing that it may be linked with another gene and can be moved by conjugation from one chromosome to another.
Giovanetti, Eleonora; Brenciani, Andrea; Lupidi, Remo; Roberts, Marilyn C.; Varaldo, Pietro E.
The cluster of virulence sensor (CovS)/responder (CovR) two-component operon (CovRS) regulates ?15% of the genes of the Group A Streptococcal pyogenes (GAS) genome. Bacterial clones containing inactivating mutations in the covS gene have been isolated from patients with virulent invasive diseases. We report herein an assessment of the nature and types of covS mutations that can occur in both virulent and nonvirulent GAS strains, and assess whether a nonvirulent GAS can attain enhanced virulence through this mechanism. A group of mice were infected with a globally-disseminated clonal M1T1 GAS (isolate 5448), containing wild-type (WT) CovRS (5448/CovR+S+), or less virulent engineered GAS strains, AP53/CovR+S+ and Manfredo M5/CovR+S+. SpeB negative GAS clones from wound sites and/or from bacteria disseminated to the spleen were isolated and the covS gene was subjected to DNA sequence analysis. Numerous examples of inactivating mutations were found in CovS in all regions of the gene. The mutations found included frame-shift insertions and deletions, and in-frame small and large deletions in the gene. Many of the mutations found resulted in early translation termination of CovS. Thus, the covS gene is a genomic mutagenic target that gives GAS enhanced virulence. In cases wherein CovS? was discovered, these clonal variants exhibited high lethality, further suggesting that randomly mutated covS genes occur during the course of infection, and lead to the development of a more invasive infection.
Mayfield, Jeffrey A.; Liang, Zhong; Agrahari, Garima; Lee, Shaun W.; Donahue, Deborah L.; Ploplis, Victoria A.; Castellino, Francis J.
Although Streptococcus pneumoniae is a leading cause of childhood disease in South East Asia, little has previously been reported regarding the epidemiology of invasive pneumococcal disease in Malaysia and very few studies have explored pneumococcal epidemiology using multilocus sequence typing (MLST). Here we describe serotype, multilocus sequence type (ST), and penicillin susceptibility of thirty pneumococcal invasive disease isolates received by the University of Malaya Medical Centre between February 2000 and January 2007 and relate this to the serotypes included in current pneumococcal conjugate vaccines. A high level of diversity was observed; fourteen serotypes and 26 sequence types (ST), (11 of which were not previously described) were detected from 30 isolates. Penicillin non-susceptible pneumococci accounted for 33% of isolates. The extent of molecular heterogeneity within carried and disease-causing Malaysian pneumococci remains unknown. Larger surveillance and epidemiological studies are now required in this region to provide robust evidence on which to base future vaccine policy.
Jefferies, Johanna M.; Mohd Yusof, Mohd Yasim; Devi Sekaran, Shamala; Clarke, Stuart C.
The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non-S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen. PMID:24750901
Shelburne, Samuel A; Sahasrabhojane, Pranoti; Saldana, Miguel; Yao, Hui; Su, Xiaoping; Horstmann, Nicola; Thompson, Erika; Flores, Anthony R
The genetically diverse viridans group streptococci (VGS) are increasingly recognized as the cause of a variety of human diseases. We used a recently developed multilocus sequence analysis scheme to define the species of 118 unique VGS strains causing bacteremia in patients with cancer; Streptococcus mitis (68 patients) and S. oralis (22 patients) were the most frequently identified strains. Compared with patients infected with non–S. mitis strains, patients infected with S. mitis strains were more likely to have moderate or severe clinical disease (e.g., VGS shock syndrome). Combined with the sequence data, whole-genome analyses showed that S. mitis strains may more precisely be considered as >2 species. Furthermore, we found that multiple S. mitis strains induced disease in neutropenic mice in a dose-dependent fashion. Our data define the prominent clinical effect of the group of organisms currently classified as S. mitis and lay the groundwork for increased understanding of this understudied pathogen.
Sahasrabhojane, Pranoti; Saldana, Miguel; Yao, Hui; Su, Xiaoping; Horstmann, Nicola; Thompson, Erika; Flores, Anthony R.
The host-restricted bacterium Streptococcus equi is the causative agent of equine strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation of the lymph nodes of the head and neck, leading to significant welfare and economic cost. S. equi is believed to have evolved from an ancestral strain of Streptococcus zooepidemicus, an opportunistic pathogen of horses and other animals. Comparison of the genome of S. equi strain 4047 with those of S. zooepidemicus identified examples of gene loss due to mutation and deletion, and gene gain through the acquisition of mobile genetic elements that have probably shaped the pathogenic specialization of S. equi. In particular, deletion of the CRISPR (clustered regularly interspaced short palindromic repeats) locus in the ancestor of S. equi may have predisposed the bacterium to acquire and incorporate new genetic material into its genome. These include four prophages and a novel integrative conjugative element. The virulence cargo carried by these mobile genetic elements is believed to have shaped the ability of S. equi to cause strangles. Further sequencing of S. zooepidemicus has highlighted the diversity of this opportunistic pathogen. Again, CRISPRs are postulated to influence evolution, balancing the need for gene gain over genome stability. Analysis of spacer sequences suggest that these pathogens may be susceptible to a limited range of phages and provide further evidence of cross-species exchange of genetic material among Streptococcus pyogenes, Streptococcus agalactiae and Streptococcus dysgalactiae. PMID:24256234
Waller, Andrew S; Robinson, Carl
The "Streptococcus milleri" group (SMG) is increasingly recognized for their role in pyogenic infections including empyema and solid organ abscesses. However, SMG disease has rarely been identified in cystic fibrosis (CF). Inherent difficulties in both growing the organisms and distinguishing SMG from less virulent oropharyngeal viridans streptococci may have led to a decreased recognition of this as a CF pathogen. We report on six cases of SMG-related infection over a 4-year time-frame occurring within an adult CF clinic in Canada, and a further four cases identified through a literature review. SMG manifested disease as bronchopulmonary exacerbations in 7 of 10 patients, and 4 of 10 patients had extra-pulmonary dissemination of SMG infection. Noticeably, pulmonary exacerbations were frequently associated with atypically malodorous sputum. Furthermore, patients clinically responded to anti-microbial therapies with no anti-Pseudomonal activity. There was a consistent correlation of SMG disease and co-colonization with P. aeruginosa leading to speculation of polymicrobial interactions resulting in enhanced virulence. SMG deserves considerable attention as a potential pathogen within the airways of patients with CF. PMID:18383109
Parkins, Michael D; Sibley, Christopher D; Surette, Michael G; Rabin, Harvey R
Many Streptococcus pyogenes (group A streptococcus [GAS]) virulence factor- and transcriptional regulator-encoding genes cluster together in discrete genomic regions. Nra is a central regulator of the FCT region. Previous studies exclusively described Nra as a transcriptional repressor of adhesin and toxin genes. Here transcriptome and proteome analysis of a serotype M49 GAS strain and an isogenic Nra mutant of this strain revealed the complete Nra regulon profile. Nra is active in all growth phases tested, with the largest regulon in the transition phase. Almost exclusively, virulence factor-encoding genes are repressed by Nra; these genes include the GAS pilus operon, the capsule synthesis operon, the cytolysin-mediated translocation system genes, all Mga region core virulence genes, and genes encoding other regulators, like the Ihk/Irr system, Rgg, and two additional RofA-like protein family regulators. Surprisingly, our experiments revealed that Nra additionally acts as a positive regulator, mostly for genes encoding proteins and enzymes with metabolic functions. Epidemiological investigations revealed strong genetic linkage of one particular Nra-repressed regulator, Ralp3 (SPy0735), with a gene encoding Epf (extracellular protein factor from Streptococcus suis). In a serotype-specific fashion, this ralp3 epf gene block is integrated, most likely via transposition, into the eno sagA virulence gene block, which is present in all GAS serotypes. In GAS serotypes M1, M4, M12, M28, and M49 this novel discrete genetic region is therefore designated the eno ralp3 epf sagA (ERES) pathogenicity region. Functional experiments showed that Epf is a novel GAS plasminogen-binding protein and revealed that Ralp3 activity counteracts Nra and MsmR regulatory activity. In addition to the Mga and FCT regions, the ERES region is the third discrete chromosomal pathogenicity region. All of these regions are transcriptionally linked, adding another level of complexity to the known GAS growth phase-dependent regulatory network. PMID:17893125
Kreikemeyer, Bernd; Nakata, Masanobu; Köller, Thomas; Hildisch, Hendrikje; Kourakos, Vassilios; Standar, Kerstin; Kawabata, Shigetada; Glocker, Michael O; Podbielski, Andreas
The LuxS-based signalling pathway has an important role in physiological and pathogenic functions that are capable of causing different infections. In the present study, cinnamaldehyde (CN) and their derivatives were evaluated for their inhibitory efficiency against LuxS by molecular modelling, docking, dynamics and free-energy calculations. Sequence and structure-similarity analysis of LuxS protein, five different amino acids were found to be highly conserved, of which GLY128 was identified as the key residue involved in the effective binding of the ligands. Quantum-polarized ligand docking protocol showed that 2nitro and 4nitro CN has a higher binding efficiency than CN, which very well corroborates with the in vitro studies. COMSTAT analysis for the microscopic images of the S. pyogenes biofilm showed that the ligands have antibiofilm potential. In addition, the results of quantitative polymerase chain reaction (qPCR) analysis revealed that the transcripts treated with the compounds showed decrease in luxS expression, which directly reflects with the reduction in expression of speB. No substantial effect was observed on the virulence regulator (srv) transcript. These results confirm that speB is controlled by the regulation of luxS. The decreased rate of S. pyogenes survival in the presence of these ligands envisaged the fact that the compounds could readily enhance opsonophagocytosis with the reduction of virulence factor secretion. Thus, the overall data supports the use of CN derivatives against quorum sensing-mediated infections caused by S. pyogenes. PMID:24436128
Beema Shafreen, Raja Mohmed; Selvaraj, Chandrabose; Singh, Sanjeev Kumar; Karutha Pandian, Shunmugiah
An apparent worldwide resurgence of invasive group A Streptococcus (GAS) infections remains unexplained. However, we recently demonstrated in mice that when an otherwise nonlethal intranasal GAS infection is preceded by a nonlethal influenza A virus (IAV) infection, induction of lethal invasive GAS infections is often the result. In the present study, we established several isogenic mutants from a GAS isolate
Shigefumi Okamoto; Shigetada Kawabata; Yutaka Terao; Hideaki Fujitaka; Yoshinobu Okuno; Shigeyuki Hamada
Background Group A Streptococcus (GAS) causes human diseases ranging in severity from uncomplicated pharyngitis to life-threatening necrotizing fasciitis and shows high rates of macrolide resistance in several countries. Our goal is to identify antimicrobial resistance in Spanish GAS isolates collected between 1994 and 2006 and to determine the molecular epidemiology (emm/T typing and PFGE) and resistance mechanisms of those resistant to erythromycin and tetracycline. Results Two hundred ninety-five out of 898 isolates (32.8%) were erythromycin resistant, with the predominance of emm4T4, emm75T25, and emm28T28, accounting the 67.1% of the 21 emm/T types. Spread of emm4T4, emm75T25 and emm28T28 resistant clones caused high rates of macrolide resistance. The distribution of the phenotypes was M (76.9%), cMLSB (20.3%), iMLSB (2.7%) with the involvement of the erythromycin resistance genes mef(A) (89.5%), msr(D) (81.7%), erm(B) (37.3%) and erm(A) (35.9%). Sixty-one isolates were tetracycline resistant, with the main representation of the emm77T28 among 20 emm/T types. To note, the combination of tet(M) and tet(O) tetracycline resistance genes were similar to tet(M) alone reaching values close to 40%. Resistance to both antibiotics was detected in 19 isolates of 7 emm/T types, being emm11T11 and the cMLSB phenotype the most frequent ones. erm(B) and tet(M) were present in almost all the strains, while erm(A), mef(A), msr(D) and tet(O) appeared in less than half of them. Conclusions Spanish GAS were highly resistant to macrolides meanwhile showed minor resistance rate to tetracycline. A remarkable correlation between antimicrobial resistance and emm/T type was noticed. Clonal spread of emm4T4, emm75T25 and emm28T28 was the main responsable for macrolide resistance where as that emm77T28 clones were it to tetraclycline resistance. A wide variety of macrolide resistance genes were responsible for three macrolide resistance phenotypes.
Biochemical, molecular chemical and molecular genetic studies were performed on an unknown Gram-positive, catalase-negative, chain-forming coccus isolated from the urine of a patient suffering from cystitis. Comparative 16S rRNA gene sequencing showed that the organism is a member of the 'pyogenic subgroup' of the genus Streptococcus and has a close affinity with Streptococcus pyogenes and Streptococcus canis. The unknown coccus was, however, readily distinguished from these species and other streptococci by biochemical tests and electrophoretic analysis of whole-cell proteins. Based on phenotypic and phylogenetic evidence, it is proposed that the unknown bacterium be classified as a new species of the genus Streptococcus, Streptococcus urinalis sp. nov. The type strain of Streptococcus urinalis is CCUG 41590T. PMID:10843060
Collins, M D; Hutson, R A; Falsen, E; Nikolaitchouk, N; LaClaire, L; Facklam, R R
Emerging respiratory disease agents, increased antibiotic resistance, and the loss of effective vaccines threaten to increase the incidence of respiratory disease in military personnel. We examine six respiratory pathogens (adenoviruses, influenza viruses, Streptococcus pneumoniae, Streptococcus pyogenes, Mycoplasma pneumoniae, and Bordetella pertussis) and review the impact of the diseases they cause, past efforts to control these diseases in U.S. military personnel, as well as current treatment and surveillance strategies, limitations in diagnostic testing, and vaccine needs. PMID:10341174
Gray, G C; Callahan, J D; Hawksworth, A W; Fisher, C A; Gaydos, J C
Emerging respiratory disease agents, increased antibiotic resistance, and the loss of effective vaccines threaten to increase the incidence of respiratory disease in military personnel. We examine six respiratory pathogens (adenoviruses, influenza viruses, Streptococcus pneumoniae, Streptococcus pyogenes, Mycoplasma pneumoniae, and Bordetella pertussis) and review the impact of the diseases they cause, past efforts to control these diseases in U.S. military personnel, as well as current treatment and surveillance strategies, limitations in diagnostic testing, and vaccine needs.
Gray, G. C.; Callahan, J. D.; Hawksworth, A. W.; Fisher, C. A.; Gaydos, J. C.
Bacterial meningitis is an important and frequent devastating disease. The present study was carried out to determine the prevalence of pyogenic meningitis in our hospital in children and to find out the sensitivity of Gram stain, CRP and latex agglutination tests for the diagnosis of pyogenic meningitis from CSF sample. Out of 150 CSF samples studied, 40 were diagnosed as pyogenic meningitis. H. influenzae was the commonest organism (22.5%), followed by Streptococcus pneumoniae 15%, Staphylococcus aureus--10%, Acinetobacter species and coagulase negative Stapylococci 7.5% each, E-coli 5%, and a case each of Klebsiella species, Group B streptococci, Proteus, Pseudomonas and Enterococci. The sensitivity of Gram stain and Latex agglutination test was 90% and that of CRP test was 62.5%. As most of the cases included in our study were treated earlier, the culture positivity was only 62.5%. Hence, Gram stain and/or latex agglutination tests, if done properly are most rapid and reliable tests for the diagnosis of pyogenic meningitis. PMID:17474275
Viswanath, G; Praveen; Hanumanthappa, A R; Chandrappa, N R; Mahesh, C Baragundi
Streptococcus parauberis is a coccoid, nonmotile, alpha-hemolytic, Gram-positive bacterium of the Streptococcaceae family. Streptococcus parauberis strain KCTC11980 was isolated from the kidney of a diseased olive flounder collected from an aquaculture farm on Jeju Island in 2010. The 2.12-Mb genome sequence consists of 44 large contigs in 16 scaffolds and contains 2,214 predicted protein-coding genes, with a G+C content of 35.4%.
Park, Myoung Ae; Kwon, Mun Gyeong; Hwang, Jee Youn; Jung, Sung Hee; Kim, Dong-Wook; Park, Jin-Young; Kim, Ji-Sun; Na, Yun-Jeong; Kim, Min-Young; Kim, Dae-Soo
Group A Streptococcus pyogenes (GAS) strain AP53 is a primary isolate from a patient with necrotizing fasciitis. These AP53 cells contain an inactivating mutation in the sensor component of the cluster of virulence (cov) responder (R)/sensor (S) two-component gene regulatory system (covRS), which enhances the virulence of the primary strain, AP53/covR(+)S(-). However, specific mechanisms by which the covRS system regulates the survival of GAS in humans are incomplete. Here, we show a key role for covRS in the regulation of opsonophagocytosis of AP53 by human neutrophils. AP53/covR(+)S(-) cells displayed potent binding of host complement inhibitors of C3 convertase, viz. Factor H (FH) and C4-binding protein (C4BP), which concomitantly led to minimal C3b deposition on AP53 cells, further showing that these plasma protein inhibitors are active on GAS cells. This resulted in weak killing of the bacteria by human neutrophils and a corresponding high death rate of mice after injection of these cells. After targeted allelic alteration of covS(-) to wild-type covS (covS(+)), a dramatic loss of FH and C4BP binding to the AP53/covR(+)S(+) cells was observed. This resulted in elevated C3b deposition on AP53/covR(+)S(+) cells, a high level of opsonophagocytosis by human neutrophils, and a very low death rate of mice infected with AP53/covR(+)S(+). We show that covRS is a critical transcriptional regulator of genes directing AP53 killing by neutrophils and regulates the levels of the receptors for FH and C4BP, which we identify as the products of the fba and enn genes, respectively. PMID:23928307
Agrahari, Garima; Liang, Zhong; Mayfield, Jeffrey A; Balsara, Rashna D; Ploplis, Victoria A; Castellino, Francis J
[Structural homology between streptolysin O (SLO) produced by streptococcus pyogenes and SLO-like protein produced by non-pathogenic streptococci and cross-reactivity of antibody against SLO-like protein to SLO].
Nine clones of non-pathogenic streptococci were isolated from the pharynges of seven healthy subjects, and grown on sheep blood agar plates with a hemolysis or gamma hemolysis, then cultured in LB broth for 16 hrs. Purified streptolysin O (SLO) purchased from Sigma Chemical Co. (Sigma-SLO), SLO antigen as a latex agglutination reagent from A company (A-SLO) and supernatants from four culture media were electrophoresed on 12% SDS-polyacrylamide gel and transferred to PVDF membranes. Immunological analyses of antibodies against SLO in healthy sera and proteins in culture medium demonstrated that healthy sera contained an antibody recognizing Sigma-SLO, A-SLO and a protein of the same size as SLO (SLO-like protein) in culture medium. These findings suggest that healthy subjects develop an antibody directed against SLO-like protein produced by non-pathogenic streptococci, and that this antibody cross-reacts with Sigma-SLO and A-SLO. Using DNA from Streptococcus pyogenes and non-pathogenic streptococci, the SLO gene and SLO-like protein gene were analyzed by direct sequencing with oligonucleotide primers designed to cover no. 74 to approximately 1900 of the SLO gene. There were three different bases resulting in amino acid substitution between the SLO gene and SLO-like protein gene, namely 101Lys (AAA) of SLO to Asn (AAT), 175Met (ATG) to Arg (AGG) and 185Asp (GAT) to Asn (AAT). Remaining 560 residues of 563 amino acids constituting SLO-like protein were homologous to SLO. Non-pathogenic streptococci on the pharynges of healthy subjects produce an SLO-like protein composed of amino acids similar to those of SLO, which induces an antibody against this SLO-like protein in serum. It is likely that an antibody against SLO-like protein in healthy sera cross-reacts with SLO and causes a pseudo-positive reaction on ASO measurement by the latex agglutination method using SLO antigen. PMID:18800623
Iijima, Kenji; Koike, Hisashi; Ota, Hiromi; Nakagawa, Mayumi; Nishikawa, Ken-Ichi; Kotani, Kazuhiko
Streptococcus agalactiae strain 138P was isolated from the kidney of diseased Nile tilapia in Idaho during a 2007 streptococcal disease outbreak. The full genome sequence of S. agalactiae 138P is 1,838,701 bp. The availability of this genome will allow comparative genomics analysis to identify genes for antigen discovery and vaccine development. PMID:24744333
Pridgeon, Julia W; Zhang, Dunhua
Streptococcus iniae ISET0901 is a virulent strain isolated in 2007 from diseased tilapia. Its full genome is 2,070,856 bp. The availability of this genome will allow comparative genomics to identify virulence genes important for the pathogenesis of streptococcosis caused by S. iniae, as well as possible immunogens for vaccine development. PMID:24903878
Pridgeon, Julia W; Zhang, Dunhua; Zhang, Lee
Streptococcus iniae ISET0901 is a virulent strain isolated in 2007 from diseased tilapia. Its full genome is 2,070,856 bp. The availability of this genome will allow comparative genomics to identify virulence genes important for the pathogenesis of streptococcosis caused by S. iniae, as well as possible immunogens for vaccine development.
Zhang, Dunhua; Zhang, Lee
ObjectiveUniversal screening for colonization by group B streptococcus (GBS) is the recommended strategy to reduce incidence of colonization in newborns and prevent neonatal GBS-related disease. This study was designed to assess maternal anxiety levels about prenatal screening and psychological impact of positive colonization test results.
P. J. Cheng; S. W. Shaw; P. Y. Lin; S. Y. Huang; Y. K. Soong
Medical abortion is not recognized as a high-risk factor for invasive pelvic infection. Here, we report two cases of group A Streptococcus (GAS; Streptococcus pyogenes) endometritis following medical abortions with a protocol of oral mifepristone and misoprostol. PMID:24829245
Gendron, Nicolas; Joubrel, Caroline; Nedellec, Sophie; Campagna, Jennifer; Agostini, Aubert; Doucet-Populaire, Florence; Casetta, Anne; Raymond, Josette; Poyart, Claire; Kernéis, Solen
Acute otitis media (AOM) is the most commonly diagnosed childhood disease, especially in infants and preschool children. Onset of AOM encourage frequent upper respiratory infections and debilitating conditions that cause nasal patency and trumpets auditory dysfunction. Complications of AOM currently are rare. We present a case of complications of acute otitis media in form of acute cerebral abscess in a 7-year-old previously healthy girl. PMID:24519780
Za??ska-Ponganis, Joanna; Jackowska, Teresa
Arcanobacterium pyogenes is an opportunistic pathogen associated with suppurative diseases in economically important food animals such as cattle, pigs, and turkeys. A. pyogenes adheres to host epithelial cells, and adhesion is promoted by the action of neuraminidase, which is expressed by this organism. However, a neuraminidase-deficient mutant of A. pyogenes only had a reduced ability to adhere to host epithelial
Paula A. Esmay; Stephen J. Billington; Malen A. Link; J. Glenn Songer; B. Helen Jost
Autoimmune diseases have environmental and genetic components. These are the microbial trigger, the immunity system component and the genetic component. Here we describe these components and how they interact. Known microbial triggers are Streptococcus pyogenes for rheumatic carditis, Proteus mirabilis for rheumatoid arthritis and Klebsiella pneumoniae for ankylosing spondylitis. The immunity system component has been clarified by realisation that no
Duncan D. Adams; John G. Knight; Alan Ebringer
This blood agar plate demonstrates that the beta-hemolytic colonies were sensitive to bacitracin and did not grow around the antibiotic containing disc. It also demonstrates that other colony types are present in this sample that are not hemolytic.
American Society For Microbiology;
Streptococcus pyogenes or Group A Streptococcus (GAS) is a major Gram-positive human pathogen that causes diverse human diseases with a high morbidity and mortality worldwide. The development of an effective GAS vaccine is hindered by the occurrence of many unique GAS serotypes, the complexity of the global epidemiology of GAS infections, and safety concerns over the cross-reactivity of some antigen-specific antibodies with human tissues and proteins. Although no licensed GAS vaccine is available, a number of candidate vaccines have been or are being evaluated in laboratory or in clinical trials. This minireview provides brief information on the progress and difficulty in the development of GAS vaccines. PMID:24372248
Song, Yingli; Zhang, Xiaolan; Lu, Chunmei; Zhang, Fengmin; Zhu, Hui
The role of respiratory viruses in transmission of Streptococcus pneumoniae is poorly understood. Key questions such as which serotypes are most fit for transmission and disease, and whether influenza virus alters these parameters in a serotype specific manner have not been adequately studied. In a novel model of ferret transmission, we demonstrated that prior infection with influenza virus of donors enhanced pneumococcal transmission and disease. Nasal wash bacterial titers, the incidence of mucosal and invasive disease, and the percentage of contacts infected were all increased. Viral infection of contact ferrets increased their susceptibility to acquisition both in terms of percentage infected and distance over which they could acquire infection. These influenza mediated effects on colonization, transmission and disease were pneumococcal strain dependent. Overall, these data argue that human studies of the relationship between respiratory viral infections, acquisition of pneumococci, and development of disease need further study to be better understood.
McCullers, Jonathan A.; McAuley, Julie L.; Browall, Sarah; Iverson, Amy R.; Boyd, Kelli L.; Normark, Birgitta Henriques
The effect of a water-soluble trimalonic acid derivative of fullerene, carboxyfullerene, against Streptococcus pyogenes infection was tested. Pretreatment with carboxyfullerene was able to protect mice from S. pyogenes infection in an air pouch model. S. pyogenes-induced death and skin injury were inhibited dose dependently by carboxyfullerene. Administration of carboxyfullerene via the peritoneum and air pouch at 3 h post-S. pyogenes infection was able to protect 33% of mice from death. Surveys of exudates of the air pouch of carboxyfullerene-treated mice revealed that survival of infiltrating neutrophils was prolonged and that the bacteria were eliminated as a result of enhanced bactericidal activity of the neutrophils. Furthermore, carboxyfullerene was able to directly inhibit in vitro growth of S. pyogenes. These data suggest that carboxyfullerene can be considered an antimicrobial agent for group A streptococcus infection.
Tsao, Nina; Luh, Tien-Yau; Chou, Chen-Kung; Wu, Jiunn-Jong; Lin, Yee-Shin; Lei, Huan-Yao
Trueperella pyogenes is a common commensal bacterium and an opportunistic pathogen associated with chronic purulent disease, particularly in ruminants. We report here the genome sequence of a T. pyogenes isolate from a severe case of bovine metritis. This is the first full record of a T. pyogenes genome.
Goldstone, Robert J.; Amos, Matt; Talbot, Richard; Schuberth, Hans-Joachim; Sandra, Olivier; Sheldon, I. Martin
Genetic characterization of strains of Streptococcus iniae recovered from morbidity and mortality of farmed rainbow trout in different provinces of Iran were studied. The Gram-positive cocci isolates were obtained from the kidney tissues of diseased rainbow trout on blood agar at 25°C for 72?h. The grown bacteria were then characterized using biochemical and molecular works. The identified 26 isolates of S. iniae producing a 513?bp in PCR procedure were then compared using random amplified polymorphic DNA (RAPD) analysis using 9 random primers. The phylogenetic tree of the RAPD product using UPMGA software included these strains in one genetic group but into two clusters. The results of this study show that S. iniae strains from the diseased rainbow trout in the north part of Iran are genetically similar to those strains in the south and west parts of the country.
Erfanmanesh, A.; Soltani, M.; Pirali, E.; Mohammadian, S.; Taherimirghaed, A.
Pyogenic sacroiliitis is rare and accounts for approximately 1-2% of osteoarticular infections in children. Considerable delay between presentation and diagnosis is recognized. Two cases of pyogenic sacroiliitis are described. The first case is a 28-month-old girl presented with acute onset of fever, pain in the left hip, and limpness. Computed tomography (CT), bone scans, and magnetic resonance imaging (MRI) of the pelvis showed characteristic findings of infectious sacroiliitis, and blood cultures were negatives. The second case is a 13-year-old girl presented with acute onset of fever, pain in the right hip, and buttock, with inability to walk. The diagnosis of pyogenic sacroiliitis was confirmed by bone scans, and CT of the pelvis and blood cultures have identified Proteus mirabilis. The two children recovered fully after 6 weeks of antimicrobial therapy. Pyogenic sacroiliitis is an uncommon disease in children. The key to successful management is early diagnosis in which CT, bone scans, and MRI findings play a crucial role. If the diagnosis is established promptly, most patients can be managed successfully with antimicrobial therapy.
Ghedira Besbes, L.; Haddad, S.; Abid, A.; Ben Meriem, Ch.; Gueddiche, M. N.
Streptococcus iniae causes meningoencephalitis and death in cultured fish species and soft-tissue infection in humans. We recently reported that S. iniae is responsible for local tissue necrosis and bacteremia in a murine subcutaneous infection model. The ability to cause bacteremia in this model is associated with a genetic profile unique to strains responsible for disease in fish and humans (J.
Jeffrey D. Fuller; Alvin C. Camus; Carla L. Duncan; Victor Nizet; Darrin J. Bast; Ronald L. Thune; Donald E. Low; J. C. S. de Azavedo
Streptococcus parauberis strain SK-417 was isolated from the brain of a diseased Sebastes ventricosus, collected from an aquaculture farm in April 2013 in Kagoshima Prefecture, Japan. The draft genome sequence, obtained with a 454 GS Junior sequencing system, consists of 33 large contigs of >500 bp, totaling 1,958,836 bp, and has a G+C content of 35.4%.
Oguro, Kazuki; Yamane, Jin; Yamamoto, Takeshi; Ohnishi, Kouhei; Oshima, Syun-ichirou
Little is known about preexisting lesions in livers of children with pyogenic liver abscess (PLA). Study of these lesions\\u000a may elucidate possible predisposing factors for the disease. In Vitória, state of Espirito Santo, Brazil, PLA in children\\u000a is frequently associated with helminthic infections and eosinophilia. We hypothesize that nematode infection with larvae migrating\\u000a through the liver is a predisposing factor
Fausto E. L. Pereira; Carlos Musso; Jane S. Castelo
In addition to causing severe invasive infections in humans, Streptococcus agalactiae, or group B Streptococcus (GBS), is also a major cause of bovine mastitis. Here we provide the first genome sequence for S. agalactiae isolated from a cow diagnosed with clinical mastitis (strain FSL S3-026). Comparison to eight S. agalactiae genomes obtained from human disease isolates revealed 183 genes specific to the bovine strain. Subsequent polymerase chain reaction (PCR) screening for the presence/absence of a subset of these loci in additional bovine and human strains revealed strong differentiation between the two groups (Fisher exact test: p < 0.0001). The majority of the bovine strain-specific genes (~85%) clustered tightly into eight genomic islands, suggesting these genes were acquired through lateral gene transfer (LGT). This bovine GBS also contained an unusually high proportion of insertion sequences (4.3% of the total genome), suggesting frequent genomic rearrangement. Comparison to other mastitis-causing species of bacteria provided strong evidence for two cases of interspecies LGT within the shared bovine environment: bovine S. agalactiae with Streptococcus uberis (nisin U operon) and Streptococcus dysgalactiae subsp. dysgalactiae (lactose operon). We also found evidence for LGT, involving the salivaricin operon, between the bovine S. agalactiae strain and either Streptococcus pyogenes or Streptococcus salivarius. Our findings provide insight intomechanismsfacilitatingenvironmentaladaptationandacquisitionofpotential virulence factors, while highlighting both the key role LGT has played in the recent evolution of the bovine S. agalactiae strain, and the importance of LGT among pathogens within a shared environment.
Richards, Vincent P.; Lang, Ping; Pavinski Bitar, Paulina D.; Lefebure, Tristan; Schukken, Ynte H.; Zadoks, Ruth N.; Stanhope, Michael J.
Electron microscopy of zoocin A-treated sensitive streptococcus cells revealed cytoplasmic disruption and ultimately complete rupture of the cell wall. Culture viability and optical density were shown to decrease rapidly and simultaneously in Streptococcus pyogenes FF22 but less quickly in the relatively more resistant Streptococcus mutans 10449. Zoocin A was shown to cleave hexaglycine in a colorimetric cell-free microtiter assay system, and it is concluded that the killing action of zoocin A, like that of lysostaphin, is most probably the result of direct cleavage of the peptidoglycan cross-links in the cell wall. The relationship between sensitivity to zoocin A and the peptidoglycan cross-linkage structure of Streptococcus zooepidemicus, Lactococcus spp., S. pyogenes, Streptococcus gordonii, Streptococcus oralis, S. mutans, and Streptococcus rattus has been evaluated.
Simmonds, R S; Pearson, L; Kennedy, R C; Tagg, J R
Streptococcus pneumoniae is a leading cause of community-acquired pneumonia and gram-positive sepsis. While multiple virulence determinants have been identified, the combination of features that determines the propensity of an isolate to cause invasive pneumococcal disease (IPD) remains unknown. In this study, we determined the genetic composition of 42 invasive and 30 noninvasive clinical isolates of serotypes 6A, 6B, and 14
Caroline Obert; Jack Sublett; Deepak Kaushal; Ernesto Hinojosa; Theresa Barton; Elaine I. Tuomanen; Carlos J. Orihuela
BackgroundSerotype-specific polysaccharide based group B streptococcus (GBS) vaccines are being developed. An understanding of the serotype epidemiology associated with maternal colonization and invasive disease in infants is necessary to determine the potential coverage of serotype-specific GBS vaccines.MethodsColonizing GBS isolates were identified by vaginal swabbing of mothers during active labor and from skin of their newborns post-delivery. Invasive GBS isolates from
Mashudu Madzivhandila; Peter V. Adrian; Clare L. Cutland; Locadiah Kuwanda; Stephanie J. Schrag; Shabir A. Madhi; Adam Ratner
The capacity of Streptococcus pneumoniae to produce capsular polysaccharide (CPS) is essential for virulence. The CPS biosynthesis proteins CpsB, CpsC, and CpsD function to regulate CPS production via tyrosine phosphorylation of CpsD. This mechanism of regulating CPS production is important for enabling S. pneumoniae to cause invasive disease. Here, we identify mutations affecting the attachment of CPS to the cell
Judy K. Morona; Renato Morona; James C. Paton
Streptococcus zooepidemicus (Sz) is a tonsillar commensal of healthy horses but with potential to opportunistically invade the lower respiratory tract. Sz is genetically variable and recombinogenic based on analysis of gene sequences including szp, szm and MLST data. Although a variety of serovars of the protective SzP are commonly harbored in the tonsils of the same horse, lower respiratory infections usually involve a single clone. Nevertheless, isolation of specific clones from epizootics of respiratory disease has been recently reported in horses and dogs in N. America, Europe and Asia. In this report, we provide evidence suggestive of lateral gene exchange and recombination between strains of Sz from cases of respiratory disease secondary to experimental equine herpes 1 virus infection in an isolated group of weanling horses and ponies. Nasal swabs of 13 of 18 weanlings with respiratory disease yielded mucoid colonies of Sz following culture. Comparison of arcC, nrdE, proS, spi, tdk, tpi and yqiL of these Sz revealed 3 Clades. Clade-1 (ST-212) and 2 (ST-24) were composed of 7 and 3 isolates, respectively. ST-24 and 212 differed in all 7 housekeeping as well as szp and szm alleles. Two isolates of Clade-1 were assigned to ST-308, a single locus variant of ST-212 that contained the proS-16 allele sequenced in ST-24. One isolate of ST-308 contained szm-2, the same allele sequenced in Clade 2 isolates; the other was positive for the szp-N2HV2 allele of Clade 2. These observations are consistent with gene transfer between Sz in the natural host and may explain formation of novel clones that invade the lower respiratory tract or cause epizootics of respiratory disease in dogs and horses. PMID:24263112
Velineni, Sridhar; Breathnach, Cormac C; Timoney, John F
In the present study we report the distribution of different serotypes of Streptococcus suis among strains isolated from diseased pigs in Québec, Canada, recovered between 2008 and 2011. Serotype 2 strains were further studied for the presence of the following virulence markers: suilysin (sly), muramidase-released protein (MRP), extracellular protein factor (epf) and the pilus encoded by the srtF cluster. Of 1004 field strains collected, 986 were confirmed to be S. suis by either the species-specific PCR targeting the gdh gene or by 16S rRNA gene sequencing analysis. Results showed that, although widely used, the species-specific PCR test can sometimes be misleading and fail to correctly identify some S. suis isolates. Serotypes 2, 3, 1/2, 4, 8 and 22 together represented 51% of S. suis strains (64.5% of typable strains). Results confirmed the relatively low prevalence of serotype 2 in North America, when compared to European and Asian countries. The vast majority of serotype 2 field strains (96%) belong to either the MRP(+), srtF pilus(+), epf(-), sly(-) (52%) or the MRP(-), srtF pilus(-), epf(-), sly(-) phenotypes (44%). Most non-typable strains (89%) presented high surface hydrophobicity, suggesting that these are poorly or non-encapsulated. Electron microscopy studies confirmed the lack of capsular polysaccharide in selected non-typable high hydrophobic strains. The role and pathogenesis of the infection caused by these strains remain to be elucidated. PMID:23177911
Gottschalk, Marcelo; Lacouture, Sonia; Bonifait, Laetitia; Roy, David; Fittipaldi, Nahuel; Grenier, Daniel
The importance of group C and G Streptococcus dysgalactiae subspecies equisimilis (S. dysgalactiae subsp. equisimilis) as a significant pathogen has recently been better recognized. S. dysgalactiae subsp. equisimilis disease can range in severity from milder skin and soft-tissue conditions such as wound infection, erysipelas, and cellulitis, to life-threatening necrotizing fasciitis and streptococcal toxic shock syndrome, thus sharing the clinical picture with S. pyogenes. The most common clinical manifestation of bacteremia is cellulitis. An increase in the incidence of S. dysgalactiae subsp. equisimilis bacteremia has been recognized. Invasive forms of this infection are most commonly found in elderly patients with underlying comorbidities and skin breakdown. The case fatality in bacteremia has been reported to be 15-18 %. In this review, the epidemiology, clinical characteristics, and emm types of S. dysgalactiae subsp. equisimilis bacteremia are summarized. PMID:24682845
Streptococcus pyogenes or Group A Streptococcus (GAS) is the etiologic agent of important human infections such as acute pharyngitis, impetigo, rheumatic fever and the streptococcal toxic shock syndrome. Binding of the complement regulatory proteins factor H, factor H-like protein 1 (FHL-1), C4b-binding protein (C4BP), or CD46 is a crucial step in the pathogenesis of these infections. M protein is the
Maria A. Oliver; José M. Rojo; Santiago Rodríguez de Córdoba; Sebastián Alberti
A total of 287 clinical isolates of Streptococcus pneumoniae (pneumococcus) were tested for their ability to undergo autolysis when treated with sodium deoxycholate. The test was positive for all but one isolate, strain DOC-1. This autolysis required the activity of an enzyme which is unique and characteristic of S. pneumoniae: a choline-dependent N-acetylmuramoyl-L-alanine amidase, the gene product of the lytA gene. We used lytA as a DNA probe to test the distribution of the autolysin gene among clinical isolates of S. pneumoniae. In dot blot hybridization experiments our probe reacted with the DNA of 60 of 60 strains tested, including the autolysis-deficient clinical isolate DOC-1. No hybridization occurred when strains of Streptococcus sanguis, Streptococcus mutans, Streptococcus pyogenes, Streptococcus (Enterococcus) faecalis, Streptococcus (Enterococcus) faecium, Streptococcus agalactiae, and Streptococcus bovis were tested. The lytA gene appears to be an ideal candidate for use as a DNA probe for the identification of S. pneumoniae. Images
Pozzi, G; Oggioni, M R; Tomasz, A
Background: Recurrent pyogenic cholangitis (RPC) is a common disease in Southeast Asia. Its classical presentation is repeated attacks of cholangitis with multiple recurrences of bile duct stones. The stones are commonly located in the left lateral segments (2 and 3) and therefore complete clearance is difficult to achieve by either endoscopic retrograde cholangiopancreatography or surgical exploration of the common bile
C. N. Tang; C. K. Tai; J. P. Y. Ha; W. T. Siu; K. K. Tsui; M. K. W. Li
Received 7 July 2007\\/Returned for modification 11 September 2007\\/Accepted 20 November 2007 Streptococcus pneumoniae causes serious infections. Treatment is difficult because of the emergence of penicillin resistance in S. pneumoniae. Pneumococcal vaccines offer the promise of control and prevention of pneumococcal infections. Serotype prevalence and penicillin susceptibility data for a country will predict the usefulness of the vaccines in that
E. M. Mokaddas; V. O. Rotimi; M. J. Albert
Pyogenic myositis is uncommon. It normally affects the large muscle groups in the lower limb or trunk and the most common causative organism is Staphylococcus aureus. We present a case of an immunocompetent man who, unusually, had a recurring form of the disease in subscapularis and teres minor. The causative organism was also highly unusual (Fusobacterium).
McElnay, Philip J.; McCann, Philip A.; Williams, Martin O.; Wakeley, Charles J.; Amirfeyz, Rouin
Group A Streptococcus (GAS, Streptococcus pyogenes) is a Gram-positive human pathogen responsible for a diverse variety of diseases, including pharyngitis, skin infections, invasive necrotizing fasciitis and autoimmune sequelae. We have recently shown that GAS cell adhesion and biofilm formation is associated with the presence of pili on the surface of these bacteria. GAS pilus proteins are encoded in the FCT (Fibronectin- Collagen-T antigen) genomic region, of which nine different variants have been identified so far. In the present study we undertook a global analysis of GAS isolates representing the majority of FCT-variants to investigate the effect of environmental growth conditions on their capacity to form multicellular communities. For FCT-types 2, 3, 5 and 6 and a subset of FCT-4 strains, we observed that acidification resulting from fermentative sugar metabolism leads to an increased ability of the bacteria to form biofilm on abiotic surfaces and microcolonies on epithelial cells. The higher biofilm forming capacity at low environmental pH was directly associated with an enhanced expression of the genes encoding the pilus components and of their transcription regulators. The data indicate that environmental pH affects the expression of most pilus types and thereby the formation of multicellular cell-adhering communities that assist the initial steps of GAS infection.
Buccato, Scilla; Kreikemeyer, Bernd; Podbielski, Andreas; Grandi, Guido; Margarit, Immaculada
Streptococcus iniae causes meningoencephalitis and death in cultured fish species and soft-tissue infection in humans. We recently reported that S. iniae is responsible for local tissue necrosis and bacteremia in a murine subcutaneous infection model. The ability to cause bacteremia in this model is associated with a genetic profile unique to strains responsible for disease in fish and humans (J. D. Fuller, D. J. Bast, V. Nizet, D. E. Low, and J. C. S. de Azavedo, Infect. Immun. 69:1994-2000, 2001). S. iniae produces a cytolysin that confers a hemolytic phenotype on blood agar media. In this study, we characterized the genomic region responsible for S. iniae cytolysin production and assessed its contribution to virulence. Transposon (Tn917) mutant libraries of commensal and disease-associated S. iniae strains were generated and screened for loss of hemolytic activity. Analysis of two nonhemolytic mutants identified a chromosomal locus comprising 9 genes with 73% homology to the group A streptococcus (GAS) sag operon for streptolysin S (SLS) biosynthesis. Confirmation that the S. iniae cytolysin is a functional homologue of SLS was achieved by PCR ligation mutagenesis, complementation of an SLS-negative GAS mutant, and use of the SLS inhibitor trypan blue. SLS-negative sagB mutants were compared to their wild-type S. iniae parent strains in the murine model and in human whole-blood killing assays. These studies demonstrated that S. iniae SLS expression is required for local tissue necrosis but does not contribute to the establishment of bacteremia or to resistance to phagocytic clearance.
Fuller, Jeffrey D.; Camus, Alvin C.; Duncan, Carla L.; Nizet, Victor; Bast, Darrin J.; Thune, Ronald L.; Low, Donald E.; de Azavedo, Joyce C. S.
Keratinocytes injured acutely by UVB light or lipopolysaccharide were used to test the hypothesis that keratinocyte injury promotes bacterial adherence and the development of group A streptococcal skin infections. Injury did not affect adherence to undifferentiated and differentiated keratinocytes, but keratinocyte differentiation promoted adherence four- to fivefold.
Darmstadt, Gary L.; Mentele, Laurel; Fleckman, Philip; Rubens, Craig E.
Streptococcus pneumoniae is a leading cause of community-acquired pneumonia and gram-positive sepsis. While multiple virulence determinants have been identified, the combination of features that determines the propensity of an isolate to cause invasive pneumococcal disease (IPD) remains unknown. In this study, we determined the genetic composition of 42 invasive and 30 noninvasive clinical isolates of serotypes 6A, 6B, and 14 by comparative genomic hybridization. Comparison of the present/absent gene matrix (i.e., comparative genomic analysis [CGA]) identified a candidate core genome consisting of 1,553 genes (73% of the TIGR4 genome), 154 genes whose presence correlated with the ability to cause IPD, and 176 genes whose presence correlated with the noninvasive phenotype. Genes identified by CGA were cross-referenced with the published signature-tagged mutagenesis studies, which served to identify core and IPD-correlated genes required for in vivo passage. Among these, two pathogenicity islands, region of diversity 8a (RD8a), which encodes a neuraminidase and V-type sodium synthase, and RD10, which encodes PsrP, a protein homologous to the platelet adhesin GspB in Streptococcus gordonii, were identified. Mice infected with a PsrP mutant were delayed in the development of bacteremia and demonstrated reduced mortality versus wild-type-infected controls. Finally, the presence of seven RDs was determined to correlate with the noninvasive phenotype, a finding that suggests some RDs may contribute to asymptomatic colonization. In conclusion, RDs are unequally distributed between invasive and noninvasive isolates, RD8a and RD10 are correlated with the propensity of an isolate to cause IPD, and PsrP is required for full virulence in mice.
Obert, Caroline; Sublett, Jack; Kaushal, Deepak; Hinojosa, Ernesto; Barton, Theresa; Tuomanen, Elaine I.; Orihuela, Carlos J.
Pyogenic granuloma or granuloma pyogenicum is a well-known oral lesion. The name pyogenic granuloma is a misnomer since the condition is not associated with pus and does not represent a granuloma histologically. Pyogenic granuloma of the oral cavity is known to involve the gingiva commonly. Extragingivally, it can occur on the lips, tongue, buccal mucosa, palate, and the like. A history of trauma is common in such sites. The etiology of the lesion is not known, though it was originally believed to be a botryomycotic infection. It is theorized that pyogenic granuloma possibly originates as a response of tissues to minor trauma and/or chronic irritation, thus opening a pathway for invasion of nonspecific microorganisms, although microorganisms are seldom demonstrated within the lesion. Pathogenesis of pyogenic granuloma is still debatable. Medline and PubMed databases were searched under the following key terms: Pathogenesis of oral pyogenic granuloma, pyogenic granuloma, and oral pyogenic granuloma. This search was limited to articles on human/animal studies which were published in English language. After reviewing the searched articles, the relevant articles were selected for the present review. Through this article, we have tried to summarize and present all the concepts of pathogenesis related to this most common and most mysterious oral lesion.
Kamal, Reet; Dahiya, Parveen; Puri, Abhiney
Pyogenic granuloma is regarded as a vascular proliferation that may result from trauma or local irritation. The most common intraoral site is the gingiva, affected in 75?% of cases. Therapy of pyogenic granuloma consists of surgical excision. Recurrence after excision may occur. In our patient, there were no post-operative complications. PMID:24722911
Baratli, J; Hölzle, F; Megahed, M
Objective: To analyze the clinical, microbiological, and radiologic features of patients without drug addiction suffering from spontaneous pyogenic vertebral osteomyelitis. Methods: We collected all microbiologically proved cases of pyogenic vertebral osteomyelitis seen between January 1980 and December 1999 in a teaching hospital. Patients with prior spinal instrumentation or surgery and injection drug users were excluded. Results: Sixty-four patients, with a
Joan M Nolla; Javier Ariza; Carmen Gómez-Vaquero; Jordi Fiter; Joaquín Bermejo; Josep Valverde; Daniel Roig Escofet; Francesc Gudiol
The capacity of Streptococcus pneumoniae to produce capsular polysaccharide (CPS) is essential for virulence. The CPS biosynthesis proteins CpsB, CpsC, and CpsD function to regulate CPS production via tyrosine phosphorylation of CpsD. This mechanism of regulating CPS production is important for enabling S. pneumoniae to cause invasive disease. Here, we identify mutations affecting the attachment of CPS to the cell wall. These mutations were located in cpsC, such that CpsC functioned independently from CpsD tyrosine phosphorylation. These mutants produced WT levels of CPS, but were unable to cause bacteremia in mice after intranasal challenge. This finding suggests that cell-wall attachment of CPS is essential for invasive pneumococcal disease; production of WT levels of CPS alone is not sufficient. We also show that cpsB mutants, which lack the phosphotyrosine-protein phosphatase, produced less CPS than the WT strain, but attached substantially more CPS to their cell wall. Thus, the phosphorylated form of CpsD promotes attachment of CPS to the cell wall.
Morona, Judy K.; Morona, Renato; Paton, James C.
Streptococcus phocae is an emerging pathogen for Chilean Atlantic salmon, Salmo salar, but the factors determining its virulence are not yet elucidated. In this work, cell surface-related properties such as hydrophobicity and haemagglutination, adhesion to mucus and cell lines, capsule detection, survival and biofilm formation in skin mucus and serum resistance of the isolates responsible for outbreaks in Atlantic salmon and seals were examined. Adhesion to hydrocarbons and the results of salt aggregation tests indicated most of the S. phocae were strongly hydrophobic. All isolates exhibited a similar ability to attach to the Chinook salmon embryo (CHSE) cells line, but were not able to enter CHSE cells. Haemagglutination was not detected. Our data clearly indicate that S. phocae can resist the killing activity of mucus and serum and proliferate in them, which could be associated with the presence of a capsular layer around the cells. Pathogenicity studies using seal and fish isolates demonstrated mortality or pathological signs in fish injected only with the Atlantic salmon isolate. No mortalities or histopathological alterations were observed in fish injected with extracellular products. PMID:21306587
González-Contreras, A; Magariños, B; Godoy, M; Irgang, R; Toranzo, A E; Avendaño-Herrera, R
A Streptococcus mutans mutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation in gidA, which is known to be involved in tRNA modification in Streptococcus pyogenes. Complementation of gidA by S. pyogenes gidA recovered the acid tolerance of S. mutans. Although the gidA-inactivated S. pyogenes mutant exhibited significantly reduced expression of multiple extracellular virulence proteins, the S. mutans mutant did not. On the other hand, the gidA mutant of S. mutans showed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed that gidA plays critical roles in the survival of S. mutans under stress conditions, including lower pH.
Li, Dan; Shibata, Yukie; Takeshita, Toru
We aimed to obtain insights on the nature of a collection of isolates presumptively identified as atypical Streptococcus pneumoniae recovered from invasive and non-invasive infections in Spain. One-hundred and thirty-two isolates were characterized by: optochin susceptibility in ambient and CO2-enriched atmosphere; bile solubility; PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802, aliB-like ORF2, and a specific 16S rRNA region; multilocus sequence analysis; and antimicrobial susceptibility. By multilocus sequence analysis, 61 isolates were S. pseudopneumoniae, 34 were pneumococci, 13 were S. mitis, and 24 remained unclassified as non-pneumococci. Among S. pseudopneumoniae isolates, 51 (83.6%) were collected from respiratory tract samples; eight isolates were obtained from sterile sources. High frequency of non-susceptibility to penicillin (60.7%) and erythromycin (42.6%) was found. Only 50.8% of the S. pseudopneumoniae isolates displayed the typical optochin phenotype originally described for this species. None harbored the cpsA gene or the pneumococcal typical lytA restriction fragment length polymorphism. The Spn9802 and the specific 16S rRNA regions were detected among the majority of the S. pseudopneumoniae isolates (n?=?59 and n?=?49, respectively). The ply and pspA genes were rarely found. A high genetic diversity was found and 59 profiles were identified. Among the S. pneumoniae, 23 were capsulated and 11 were non-typeable. Three non-typeable isolates, associated to international non-capsulated lineages, were recovered from invasive disease sources. In conclusion, half of the atypical pneumococcal clinical isolates were, in fact, S. pseudopneumoniae and one-fourth were other streptococci. We identified S. pseudopneumoniae and non-typeable pneumococci as cause of disease in Spain including invasive disease.
Fenoll, Asuncion; Linares, Josefina; de Lencastre, Herminia; Ardanuy, Carmen; Sa-Leao, Raquel
Streptococcus pneumoniae is a commensal of the human nasopharynx but can cause invasive diseases, including otitis media, pneumonia, sepsis, and meningitis. The capsular polysaccharide (capsule) is a critical virulence factor required for both asymptomatic colonization and invasive disease, yet the expression level is different in each anatomical site. During colonization, reduced levels of capsule promote binding to the host epithelium and biofilm formation, while during systemic infection, increased capsule is required to evade opsonophagocytosis. How this regulation of capsule expression occurs is incompletely understood. To investigate the contribution of transcriptional regulation on capsule level in the serotype 4 strain TIGR4, we constructed two mutants harboring a constitutive promoter that was either comparably weaker (Pcat) or stronger (PtRNAGlu) than the wild-type (WT) capsule promoter, Pcps. Mild reductions in cpsA and cpsE transcript levels in the Pcat promoter mutant resulted in a 2-fold reduction in total amounts of capsule and in avirulence in murine models of lung and blood infection. Additionally, the PtRNAGlu mutant revealed that, despite expressing enhanced levels of cpsA and cpsE and possessing levels of capsule comparable to those of WT TIGR4, it was still significantly attenuated in all tested in vivo niches. Further analysis using chimeric promoter mutants revealed that the WT -10 and -35 boxes are required for optimal nasopharyngeal colonization and virulence. These data support the hypothesis that dynamic transcriptional regulation of the capsule operon is required and that the core promoter region plays a central role in fine-tuning levels of capsule to promote colonization and invasive disease. PMID:24478084
Shainheit, Mara G; Mulé, Matthew; Camilli, Andrew
Otitis media is the second most common infection in children and the leading cause for seeking medical advice. Indigenous populations such as the Inuits, indigenous Australians and American Indians have a very high prevalence of otitis media and are considered to be high-risk populations. Streptococcus pneumoniae, one of the three main bacterial causes of otitis media, colonises the nasopharynx prior to disease development. In high-risk populations, early acquisition of high bacterial loads increases the prevalence of otitis media. In these settings, current treatment strategies are insufficient. Vaccination is effective against invasive pneumococcal infection but has a limited impact on otitis media. Decreasing the bacterial loads of otitis media pathogens and/or colonising the nasopharynx with beneficial bacteria may reduce the prevalence of otitis media. Probiotics are live microorganisms that offer health benefits by modulating the microbial community and enhancing host immunity. The available data suggest that probiotics may be beneficial in otitis media. This review discusses the potential use of probiotics to reduce pathogen colonisation and decrease the prevalence of otitis media, providing justification for further investigation. PMID:23512465
John, M; Dunne, E M; Licciardi, P V; Satzke, C; Wijburg, O; Robins-Browne, R M; O'Leary, S
Pyogenic granulomas are benign vascular proliferations of the skin and mucous membranes. We present a case report of a 13-year-old uncircumcised boy with phimosis and a pyogenic granuloma of the glans penis. The relationship between these lesions, phimosis, smegma, and circumcision is discussed. When the lesion is found in conjunction with phimosis, consideration should be given for circumcision. Close follow-up
Kimberly M Eickhorst; Michael J Nurzia; Joseph G Barone
Pyogenic granulomas are benign vascular proliferations of the skin and mucous membranes. We present a case report of a 13-year-old uncircumcised boy with phimosis and a pyogenic granuloma of the glans penis. The relationship between these lesions, phimosis, smegma, and circumcision is discussed. When the lesion is found in conjunction with phimosis, consideration should be given for circumcision. Close follow-up to rule out recurrence is necessary. PMID:12639669
Eickhorst, Kimberly M; Nurzia, Michael J; Barone, Joseph G
Introduction Streptococcus agalactiae or group B streptococcus is a Gram-positive pathogen that is typically associated with neonatal disease and infection in pregnant women. Group B streptococcus also causes invasive infections in non-pregnant adults including urinary tract infections. The spectrum of urinary tract infections caused by group B streptococcus includes cystitis, pyelonephritis, urosepsis and asymptomatic bacteriuria, which is particularly common among elderly individuals. A rare form of invasive group B streptococcus infection in adults is secondary abscess. Here, we present the first reported case of a patient who developed an unusual, massive abdominopelvic abscess secondary to acute group B streptococcus urinary tract infection. Case presentation A 46-year-old African-American woman presented to the University Emergency Department complaining of urinary tract infection symptoms and severe abdominal pain. Diagnostic imaging by transvaginal ultrasound and computed tomography revealed a massive peripherally-enhancing, low-attenuating fluid collection within her pelvis. The patient’s abdominopelvic abscess was drained by ultrasound-guided drainage and this yielded a septic aspirate that was culture positive for abundant S. agalactiae. A recent history of urinary tract infection symptoms in the patient suggested that her abscess developed secondary to cystitis. Complete resolution of the abscess as a favorable outcome was achieved in this case following surgical drainage and appropriate antimicrobial therapy. Conclusion Acute bacterial urinary tract infection leading to an abdominopelvic abscess has not previously been reported in the literature. This case report defines a new disease etiology associated with acute streptococcal cystitis and it will be of interest in cases of urinary tract infections where there is an association with abdominal and/or pelvic pain. A brief review of the literature on unusual secondary abscesses due to group B streptococcus is provided alongside this case to highlight the clinical significance and prognoses of these rare infections. Finally, this case emphasizes the requirement to distinguish unusual etiologies of pyogenic abscesses in order to guide successful clinical management and to treat patients with antibiotics active against the causal organism.
Streptococcus equi subspecies zooepidemicus (Sz) is a tonsillar and mucosal commensal of healthy horses with the potential to cause opportunistic infections of the distal respiratory tract stressed by virus infection, transportation, training or high temperature. The invasive clone varies from horse to horse with little evidence of lateral transmission in the group. Tonsillar isolates are non-mucoid although primary isolates from opportunist lower respiratory tract infections may initially be mucoid. In this study, a novel stably mucoid Sz (SzNC) from a clonal epizootic of respiratory disease in horses in different parts of New Caledonia is described. SzNC (ST-307) was isolated in pure culture from transtracheal aspirates and as heavy growths from 80% of nasal swabs (n=31). Only 4% of swabs from unaffected horses (n=25) yielded colonies of Sz. A viral etiology was ruled out based on culture and early/late serum antibody screening. Evidence for clonality of SzNC included a mucoid colony phenotype, SzP and SzM sequences, and multilocus sequence typing. SzNC, with the exception of isolates at the end of the outbreak, was hyaluronidase positive. Its SzP protein was composed of an N2 terminal, and HV4 variable region motifs and 18 carboxy terminal PEPK repeats. Biotin labeling of surface proteins revealed DnaK and alanyl-tRNA synthetase (AlaS) on the surface of clonal isolates, but not on non-clonal non-mucoid Sz from horses in the epizootic or unrelated US isolates. Reactivity of these proteins and SzP with convalescent serum indicated expression during infection. PMID:24618399
Velineni, Sridhar; Desoutter, Denise; Perchec, Anne-Marie; Timoney, John F
Streptococcus anginosus is an emerging pathogen, but little is known about its virulence factors. To detect the genes responsible for ?-haemolysis we performed genomic mutagenesis of the ?-haemolytic S. anginosus type strain ATCC 12395 using the vector pGhost9:ISS1. Integration site analysis of 15 non-haemolytic mutants identified a gene cluster with high homology to the genes of the streptolysin S (SLS) encoding sag gene cluster of S. pyogenes. The gene cluster harbours 10 open reading frames displaying significant similarities to the S. pyogenes genes sagA-sagI, with the identities on protein level ranging from 38 to 87%. Complementation assays of S. anginosus sagB and sagD integration mutants with the respective genes confirmed their importance for ?-haemolysin production and suggest the presence of post-translational modifications in S. anginosus SLS similar to SLS of S. pyogenes. Characterization of the S. anginosus haemolysin in comparison to the S. pyogenes SLS showed that the haemolysin is surface bound, but in contrast to S. pyogenes neither fetal calf serum nor RNA was able to stabilize the haemolysin of S. anginosus in culture supernatants. Inhibition of ?-haemolysis by polyethylene glycol of different sizes was carried out, giving no evidence of a pore-forming haemolytic mechanism. Analysis of a whole genome shotgun sequence of Streptococcus constellatus, a closely related streptococcal species that belongs to the S. anginosus group, revealed a similar sag gene cluster. Employing a genomic mutagenesis strategy we were able to determine an SLS encoding gene cluster in S. anginosus and demonstrate its importance for ?-haemolysin production in S. anginosus. PMID:23594064
Asam, D; Mauerer, S; Walheim, E; Spellerberg, B
Background.?Pneumococcal serotypes are represented by a varying number of clonal lineages with different genetic contents, potentially affecting invasiveness. However, genetic variation within the same genetic lineage may be larger than anticipated. Methods.?A total of 715 invasive and carriage isolates from children in the same region and during the same period were compared using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Bacterial genome sequencing, functional assays, and in vivo virulence mice studies were performed. Results.?Clonal types of the same serotype but also intraclonal variants within clonal complexes (CCs) showed differences in invasive-disease potential. CC138, a common CC, was divided into several PFGE patterns, partly explained by number, location, and type of temperate bacteriophages. Whole-genome sequencing of 4 CC138 isolates representing PFGE clones with different invasive-disease potentials revealed intraclonal sequence variations of the virulence-associated proteins pneumococcal surface protein A (PspA) and pneumococcal choline-binding protein C (PspC). A carrier isolate lacking PcpA exhibited decreased virulence in mice, and there was a differential binding of human factor H, depending on invasiveness. Conclusions.?Pneumococcal clonal types but also intraclonal variants exhibited different invasive-disease potentials in children. Intraclonal variants, reflecting different prophage contents, showed differences in major surface antigens. This suggests ongoing immune selection, such as that due to PspC-mediated complement resistance through varied human factor H binding, that may affect invasiveness in children.
Browall, Sarah; Norman, Martin; Tangrot, Jeanette; Galanis, Ilias; Sjostrom, Karin; Dagerhamn, Jessica; Hellberg, Christel; Pathak, Anuj; Spadafina, Tiziana; Sandgren, Andreas; Battig, Patrick; Franzen, Oscar; Andersson, Bjorn; Ortqvist, Ake; Normark, Staffan; Henriques-Normark, Birgitta
Pyogenic spondylodiscitis (PS) is an uncommon but important infection, that represents 3-5% of all cases of osteomyelitis. The annual incidence in Europe has been estimated to be from 0.4 to 2.4/100,000. A has been reported, with peaks at age less than 20 years and in the group aged 50-70 years. The incidence of PS seems to be increasing in the last years as a result of the higher life expectancy of older patients with chronic debilitating diseases, the rise in the prevalence of immunosuppressed patients, intravenous drug abuse, and the increase in spinal instrumentation and surgery. PS is in most cases a hematogenous infection. Staphylococcus aureus is the most frequent causative microorganism, accounting for about one half of the cases of PS. Gram-negative rods are causative agents in 7-33% of PS cases. Coagulase-negative staphylococci (CoNS) have been reported in 5-16% of cases. Staphylococcus epidermidis is often related to post-operative infections and intracardiac device-related bacteremia. Unremitting back pain, characteristically worsening during the night, is the most common presenting symptom, followed by fever that is present in about one half of the cases. The mortality of PS ranges from 0 to 11%. In a significant number of cases, recrudescence, residual neurological defects or persistent pain may occur. PMID:22655478
Fantoni, M; Trecarichi, E M; Rossi, B; Mazzotta, V; Di Giacomo, G; Nasto, L A; Di Meco, E; Pola, E
Tumor necrosis factor-alpha (TNF-?) antagonists have advanced treatment of psoriasis and other chronic inflammatory diseases but are not free of adverse effects. Pyogenic granuloma is yet described in literature as a dermatological side effect of multiple drugs such as retinoids, antiretroviral, and antineoplastic drugs but, to the best of our knowledge, it has never been reported among the adverse skin reactions following anti-TNF-? therapy. We report on a 20-year-old Caucasian man with psoriatic arthritis who developed multiple eruptive periungual and subungual pyogenic granulomas following treatment with TNF-? antagonist etanercept. PMID:24552415
Patruno, Cataldo; Balato, Nicola; Cirillo, Teresa; Napolitano, Maddalena; Ayala, Fabio
Streptococcus pyogenes (group A streptococcus, GAS) is a human bacterial pathogen of global significance, causing severe invasive diseases associated with serious morbidity and mortality. To survive within the host and establish an infection, GAS requires essential nutrients, including iron. The streptococcal hemoprotein receptor (Shr) is a surface-localized GAS protein that binds heme-containing proteins and extracellular matrix components. In this study, we employ targeted allelic exchange mutagenesis to investigate the role of Shr in the pathogenesis of the globally disseminated serotype M1T1 GAS. The shr mutant exhibited a growth defect in iron-restricted medium supplemented with ferric chloride, but no significant differences were observed in neutrophil survival, antimicrobial peptide resistance, cell surface charge, fibronectin-binding or adherence to human epithelial cells and keratinocytes, compared with wild-type. However, the shr mutant displayed a reduction in human blood proliferation, laminin-binding capacity and was attenuated for virulence in in vivo models of skin and systemic infection. We conclude that Shr augments GAS adherence to laminin, an important extracellular matrix attachment component. Furthermore, Shr-mediated iron uptake contributes to GAS growth in human blood, and is required for full virulence of serotype M1T1 GAS in mouse models of invasive disease.
Dahesh, Samira; Nizet, Victor; Cole, Jason N.
Invasive disease caused by the encapsulated bacteria Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide, despite the introduction of successful conjugate polysaccharide vaccines that target disease-associated strains. In addition, resistance, or more accurately reduced susceptibility, to therapeutic antibiotics is spreading in populations of these organisms. There is therefore a continuing requirement for the surveillance of vaccine and non-vaccine antigens and antibiotic susceptibilities among isolates from invasive disease, which is only partially met by conventional methods. This need can be met with molecular and especially nucleotide sequence-based typing methods, which are fully developed in the case of N. meningitidis and which could be more widely deployed in clinical laboratories for S. pneumoniae and H. influenzae.
Harrison, Odile B.; Brueggemann, Angela B.; Caugant, Dominique A.; van der Ende, Arie; Frosch, Matthias; Gray, Stephen; Heuberger, Sigrid; Krizova, Paula; Olcen, Per; Slack, Mary; Taha, Muhamed-Kheir; Maiden, Martin C. J
We report 2 cases of children with group A streptococcus pyogenes pleuropneumonia, in one child associated with Kawasaki disease and in the other with streptococcal toxic shock syndrome. These 2 features, with theoretically well-defined clinical and biological criteria, are difficult to differentiate in clinical practice, however, likely due to their pathophysiological links. In case of clinical doubt, an echocardiography needs to be performed to search for coronary involvement and treatment including intravenous immunoglobulins, and an antibiotic with an anti-toxin effect such as clindamycin has to be started early. PMID:22041597
Bosland, A; Arlaud, K; Rousset-Rouvière, C; Fouilloux, V; Paut, O; Dubus, J-C; Bosdure, E
Pyogenic spondylitis and tuberculous spondylitis are common causes of spinal infection. It is difficult to differentiate tuberculous spondylitis and pyogenic spondylitis clinically and radiologically. Recently magnetic resonance imaging has been reported to be beneficial for early diagnosis and differential diagnosis of the spondylitis, and is being used extensively for diagnosis. However, the diagnosis must be considered in combination with corresponding changes in clinical manifestations, radiological findings, blood and tissue cultures and histopathological findings. Conservative treatments, including antimicrobial medications, are started initially. Surgical treatments, which include anterior or posterior approach, single-stage or two-stage surgery, with or without instrumentation, may be performed as indicated.
Background Understanding the distribution of disease in wildlife is key to predicting the impact of emerging zoonotic one health concerns, especially for wildlife species with extensive human and livestock interfaces. The widespread distribution and complex interactions of white-tailed deer (Odocoileus virginianus) with humans suggest deer population health and management may have implications beyond stewardship of the animals. The intracranial abscessation suppurative meningitis (IASM) disease complex in deer has been linked to Arcanobacterium pyogenes, an under-diagnosed and often misdiagnosed organism considered commensal in domestic livestock but associated with serious disease in numerous species, including humans. Methods Our study used standard bacterial culture techniques to assess A. pyogenes prevalence among male deer sampled across six physiogeographic regions in Maryland and male and female deer in the Upper Eastern Shore under Traditional Deer Management (TDM) and Quality Deer Management (QDM), a management protocol that alters population demographics in favor of older male deer. Samples were collected from antler pedicles for males, the top of the head where pedicles would be if present for females, or the whole dorsal frontal area of the head for neonates. We collected nasal samples from all animals by swabbing the nasopharyngeal membranes. A gram stain and catalase test were conducted, and aerobic bacteria were identified to genus and species when possible. We evaluated the effect of region on whether deer carried A. pyogenes using Pearson's chi-square test with Yates’ continuity correction. For the white-tailed deer management study, we tested whether site, age class and sex predisposed animals to carrying A. pyogenes using binary logistic regression. Results A. pyogenes was detected on deer in three of the six regions studied, and was common in only one region, the Upper Eastern Shore. In the Upper Eastern Shore, 45% and 66% of antler and nasal swabs from deer were positive for A. pyogenes, respectively. On the Upper Eastern Shore, prevalence of A. pyogenes cultured from deer did not differ between management areas, and was abundant among both sexes and across all age classes. No A. pyogenes was cultured from a small sample of neonates. Conclusion Our study indicates A. pyogenes may be carried widely among white-tailed deer regardless of sex or age class, but we found no evidence the pathogen is acquired in utero. The distribution of A. pyogenes across regions and concentration in a region with low livestock levels suggests the potential for localized endemicity of the organism and the possibility that deer may serve as a maintenance reservoir for an emerging one health concern.
Turner, Melissa M.; DePerno, Christopher S.; Conner, Mark C.; Eyler, T. Brian; Lancia, Richard A.; Klaver, Robert W.; Stoskopf, Michael K.
Death and injuries from riding motorcycles have been well documented. We describe a case of pyogenic granuloma that we feel was indirectly related to a motorcycle accident. Clinicians should be familiar with both the diagnosis and treatment of this entity. PMID:23322146
Tatusov, Michael; Reddy, Swapna; Federman, Daniel G
Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa.
Streptococcus pyogenes (group A Streptococcus, GAS) and Moraxella catarrhalis are important colonizers and (opportunistic) pathogens of the human respiratory tract. However, current knowledge regarding colonization and pathogenic potential of these two pathogens is based on work involving single bacterial species, even though the interplay between respiratory bacterial species is increasingly important in niche occupation and the development of disease. Therefore, to further define and understand polymicrobial species interactions, we investigated whether gene expression (and hence virulence potential) of GAS would be affected upon co-culture with M. catarrhalis. For co-culture experiments, GAS and M. catarrhalis were cultured in Todd-Hewitt broth supplemented with 0.2% yeast extract (THY) at 37°C with 5% CO2 aeration. Each strain was grown in triplicate so that triplicate experiments could be performed. Bacterial RNA was isolated, cDNA synthesized, and microarray transcriptome expression analysis performed. We observed significantly increased (?4-fold) expression for genes playing a role in GAS virulence such as hyaluronan synthase (hasA), streptococcal mitogenic exotoxin Z (smeZ) and IgG endopeptidase (ideS). In contrast, significantly decreased (?4-fold) expression was observed in genes involved in energy metabolism and in 12 conserved GAS two-component regulatory systems. This study provides the first evidence that M. catarrhalis increases GAS virulence gene expression during co-culture, and again shows the importance of polymicrobial infections in directing bacterial virulence.
Verhaegh, Suzanne J. C.; Flores, Anthony R.; van Belkum, Alex; Musser, James M.; Hays, John P.
OBJECTIVE. Radiologists are taught that pyogenic osteomyelitis in children rarely crosses the growth plate because terminal vessels of nutrient arteries loop at the physis, predisposing the metaphysis to hematogenous infection. However, we note that MRI frequently shows osteomyelitis involving both sides of the physis. The purpose of this article is to document our observation that pyogenic osteomyelitis crosses the growth plate more frequently in the pediatric patient population than is classically taught. MATERIALS AND METHODS. All pediatric patients (age, 2-16 years) with clinically suspected osteomyelitis from 2004 to 2009 were reviewed for transphyseal disease on a consensus basis. To reveal the statistical significance, we applied a z test to our results. We quantified rare as 20% or less and used a z test to determine whether 27 of 32 (81%) differed from rare. RESULTS. Of 32 subjects, 81% showed transphyseal infection. In our study, the z test revealed that transphyseal infection occurred significantly more often than what would be considered rare (z = 4.75, p < 0.01). CONCLUSION. In our pediatric patient population, we have documented a higher frequency of transphyseal osteomyelitis (81%) than metaphyseal osteomyelitis in pyogenic infections. When our findings are statistically compared with an expected rate of 20%, they cannot be attributed to chance alone. This raises some doubt regarding the conventional understanding of pediatric pyogenic osteomyelitis. PMID:24951214
Gilbertson-Dahdal, Dorothy; Wright, Jason E; Krupinski, Elizabeth; McCurdy, Wendy E; Taljanovic, Mihra S
Actinomyces pyogenes is the second most frequently encountered pathogen, next only to Fusobacterium necrophorum, in liver abscesses of feedlot cattle. Ninety-one isolates, presumptively identified as A. pyogenes, isolated from liver abscesses of cattle were studied. Biochemical characteristics determined by the API 20 Strep kit were similar to those reported previously for A. pyogenes isolated from other infections, except that 18% of isolates hydrolyzed esculin. Nine isolates that resembled A. pyogenes in morphology and in certain biochemical characteristics, but fermented mannitol and/or raffinose, were called A. pyogenes-like (APL) organisms. The five antimicrobial agents, bacitracin, chlortetracycline, oxytetracycline, tylosin, and virginiamycin were inhibitory to all strains of A. pyogenes and APLs. Generally, APL organisms had higher mean hemolytic and leukotoxic activities than A. pyogenes. All isolates of A. pyogenes and APLs produced proteases and neuraminidases. Ribotyping with endonucleases, including BstEII, ClaI, EcoRI, EcoRV, HaeIII, MboI, PvuII, SalI, and SmaI alone or in combinations, showed considerable genetic heterogeneity in both A. pyogenes and APLs. No specific ribopattern characteristic of each group was observed with any of the endonuclease used. The origin of A. pyogenes and APLs and the relative importance of APLs in causing liver abscesses in feedlot cattle are not known. PMID:9646478
Narayanan, S; Nagaraja, T G; Staats, J; Chengappa, M M; Oberst, R D
Pyogenic sacroiliitis is a rare osteoarticular infection, occurring most frequently in children and young adults. Diagnosis of the disease is challenging because of a general lack of awareness of the disease and its nonspecific signs and symptoms. Staphylococcus aureus is the most common causative bacteria in pyogenic sacroiliitis. Methicillin-resistant S. aureus (MRSA) has typically been considered a hospital-associated pathogen; however, community-acquired (CA)-MRSA infections are becoming increasingly common in Korea. We report the first domestic case of acute pyogenic sacroiliitis with abscess and bacteremia caused by CA-MRSA. The pathogen carried the type IV-A staphylococcal cassette chromosome mec (SCCmec) without the Panton-Valentine leukocidin (PVL) gene, and was identified as sequence type (ST) 72 by multilocus sequence typing. PMID:24475359
Kim, Suyoung; Lee, Kang Lock; Baek, Hae Lim; Jang, Seung Jun; Moon, Song Mi; Cho, Yong Kyun
Pyogenic sacroiliitis is a rare osteoarticular infection, occurring most frequently in children and young adults. Diagnosis of the disease is challenging because of a general lack of awareness of the disease and its nonspecific signs and symptoms. Staphylococcus aureus is the most common causative bacteria in pyogenic sacroiliitis. Methicillin-resistant S. aureus (MRSA) has typically been considered a hospital-associated pathogen; however, community-acquired (CA)-MRSA infections are becoming increasingly common in Korea. We report the first domestic case of acute pyogenic sacroiliitis with abscess and bacteremia caused by CA-MRSA. The pathogen carried the type IV-A staphylococcal cassette chromosome mec (SCCmec) without the Panton-Valentine leukocidin (PVL) gene, and was identified as sequence type (ST) 72 by multilocus sequence typing.
Kim, Suyoung; Lee, Kang Lock; Baek, Hae Lim; Jang, Seung Jun; Moon, Song Mi
Infratentorial subdural empyema is an extremely rare condition which unfortunately mimics pyogenic meningitis in 75% of cases. While an ill-planned lumbar puncture in these cases may be fatal, an inadvertent delay in treatment may be detrimental to the outcome for the patient. We present a case of a young boy with long standing history of chronic suppurative otitis media (CSOM) presenting with an infratentorial empyema with features suggestive of pyogenic meningitis. We also review the available literature to further define the condition in terms of clinical features, treatment options, and outcome. A misdiagnosis of this condition with failure to institute appropriate surgical intervention and antibiotic therapy is potentially life threatening. We highlight this rare condition which requires a high degree of suspicion especially in the presence of associated risk factors.
Gupta, Anurag; Karanth, Suman S; Raja, A
The first gold-mercaptopropionic acid-polyethylenimine composite based electrochemical DNA biosensor was fabricated for the early detection of Streptococcus pyogenes infection in humans causing rheumatic heart disease (heart valve damage). No biosensor is available for the detection of rheumatic heart disease (RHD). Therefore, the mga gene based sensor was developed by the covalent immobilization of a 5'-carboxyl modified single stranded DNA probe onto the gold composite electrode. The immobilized probe was hybridized with the genomic DNA (G-DNA) of S. pyogenes from throat swabs and the electrochemical response was measured by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance (EI). Covalent immobilization of the probe onto the gold composite and its hybridization with G-DNA was characterized by FTIR and SEM. The sensitivity of the sensor was 110.25 ?A cm(-2) ng(-1) with DPV and the lower limit of detection was 10 pg per 6 ?L. The sensor was validated with patient throat swab samples and results were compared with available methods. The sensor is highly specific to S. pyogenes and can prevent damage to heart valves by the early detection of the infection in only 30 min. PMID:24875529
Singh, Swati; Kaushal, Ankur; Khare, Shashi; Kumar, Pradeep; Kumar, Ashok
Pyogenic granuloma is thought to represent an exuberant tissue response to a local irritation or trauma. It is a reactional response to constant minor trauma and it might be related to hormonal changes. Clinically, these lesions usually present as single nodules or sessile papules with smooth or lobulated surfaces. These may be seen in any size, from a few millimetres to several centimetres. Pyogenic granuloma of the oral cavity is known to involve the gingiva more commonly (75% of all the cases). An extragingival occurrence of pyogenic granuloma is rare. This paper has described an extragingival pyogenic granuloma which occurred on the upper labial mucosa in a 30 years old female patient.
K A, Kamala; Ashok, L.; G P, Sujatha
Vascular lesions represent one of the rare disorders affecting overall quality of life of a child. A wide variety of these conditions are known, ranging from a simple nevus to life-threatening hemangiomas. These conditions make the treatment options more complex due to the fear of uncontrollable bleeding. The present case is one of the rare combinations of Sturge-Weber syndrome and pyogenic granuloma. Conditions of importance and treatment options keeping hemangioma in mind are discussed.
Mopagar, Viddyasagar P.; Choudhari, Shantanu; Subbaraya, Dwijendra Kocherlakota; Peesapati, Sudha
Streptococcus pyogenes or Group A Streptococcus (GAS) is the etiologic agent of important human infections such as acute pharyngitis, impetigo, rheumatic fever and the streptococcal toxic shock syndrome. Binding of the complement regulatory proteins factor H, factor H-like protein 1 (FHL-1), C4b-binding protein (C4BP), or CD46 is a crucial step in the pathogenesis of these infections. M protein is the GAS protein that generally mediates these interactions. However, a detailed analysis of the reports that have investigated the binding of complement regulatory components to GAS indicates that this microorganism has evolved alternative mechanisms for the recruitment of complement regulatory proteins to the bacterial surface. This article summarizes these data to provide a starting point for future research aimed at the characterization of additional mechanisms developed by GAS to evade the immune system. PMID:19388169
Oliver, Maria A; Rojo, José M; Rodríguez de Córdoba, Santiago; Alberti, Sebastián
Streptococcus zooepidemicus of Lancefield group C is a highly variable tonsillar and mucosal commensal that usually is associated with opportunistic infections of the respiratory tract of vertebrate hosts. More-virulent clones have caused epizootics of severe respiratory disease in dogs and horses. The virulence factors of these strains are poorly understood. The antiphagocytic protein SeM is a major virulence factor and protective antigen of Streptococcus equi, a clonal biovar of an ancestral S. zooepidemicus strain. Although the genome of S. zooepidemicus strain H70, an equine isolate, contains a partial homolog (szm) of sem, expression of the gene has not been documented. We have identified and characterized SzM from an encapsulated S. zooepidemicus strain from an epizootic of equine respiratory disease in New Caledonia. The SzM protein of strain NC78 (SzMNC78) has a predicted predominantly alpha-helical fibrillar structure with an LPSTG cell surface anchor motif and resistance to hot acid. A putative binding site for plasminogen is present in the B repeat region, the sequence of which shares homology with repeats of the plasminogen binding proteins of human group C and G streptococci. Equine plasminogen is activated in a dose-dependent manner by recombinant SzMNC78. Only 23.20 and 25.46% DNA homology is shared with SeM proteins of S. equi strains CF32 and 4047, respectively, and homology ranges from 19.60 to 54.70% for SzM proteins of other S. zooepidemicus strains. As expected, SzMNC78 reacted with convalescent-phase sera from horses with respiratory disease associated with strains of S. zooepidemicus. SzMNC78 resembles SeM in binding equine fibrinogen and eliciting strong protective antibody responses in mice. Sera of vaccinated mice opsonized S. zooepidemicus strains NC78 and W60, the SzM protein of which shared partial amino acid homology with SzMNC78. We conclude that SzM is a protective antigen of NC78; it was strongly reactive with serum antibodies from horses during recovery from S. zooepidemicus-associated respiratory disease.
Streptococcus zooepidemicus of Lancefield group C is a highly variable tonsillar and mucosal commensal that usually is associated with opportunistic infections of the respiratory tract of vertebrate hosts. More-virulent clones have caused epizootics of severe respiratory disease in dogs and horses. The virulence factors of these strains are poorly understood. The antiphagocytic protein SeM is a major virulence factor and protective antigen of Streptococcus equi, a clonal biovar of an ancestral S. zooepidemicus strain. Although the genome of S. zooepidemicus strain H70, an equine isolate, contains a partial homolog (szm) of sem, expression of the gene has not been documented. We have identified and characterized SzM from an encapsulated S. zooepidemicus strain from an epizootic of equine respiratory disease in New Caledonia. The SzM protein of strain NC78 (SzM(NC78)) has a predicted predominantly alpha-helical fibrillar structure with an LPSTG cell surface anchor motif and resistance to hot acid. A putative binding site for plasminogen is present in the B repeat region, the sequence of which shares homology with repeats of the plasminogen binding proteins of human group C and G streptococci. Equine plasminogen is activated in a dose-dependent manner by recombinant SzM(NC78). Only 23.20 and 25.46% DNA homology is shared with SeM proteins of S. equi strains CF32 and 4047, respectively, and homology ranges from 19.60 to 54.70% for SzM proteins of other S. zooepidemicus strains. As expected, SzM(NC78) reacted with convalescent-phase sera from horses with respiratory disease associated with strains of S. zooepidemicus. SzM(NC78) resembles SeM in binding equine fibrinogen and eliciting strong protective antibody responses in mice. Sera of vaccinated mice opsonized S. zooepidemicus strains NC78 and W60, the SzM protein of which shared partial amino acid homology with SzM(NC78). We conclude that SzM is a protective antigen of NC78; it was strongly reactive with serum antibodies from horses during recovery from S. zooepidemicus-associated respiratory disease. PMID:23740925
Velineni, Sridhar; Timoney, John F
A patient with multiple pyogenic abscesses in both lobes of the liver secondary to asymptomatic sigmoid diverticulitis is presented. The rarity of this illness is noted. It is suggested that barium enema be performed in patients who present with pyogenic liver abscess of unknown etiology because of the association with asymptomatic sigmoid diverticulitis. Images Fig. 1. Fig. 2. Fig. 3.
Wallack, M K; Brown, A S; Austrian, R; Fitts, W T
Arcanobacterium pyogenes, a common inhabitant of the mucosal surfaces of livestock, is also a pathogen associated with a variety of infections. In livestock, A. pyogenes is exposed to antimicrobial agents used for prophylaxis and therapy, notably tylosin, a macrolide used extensively for the prevention of liver abscessation in feedlot cattle in the United States. Many, but not all, tylosin-resistant A.
B. Helen Jost; Hien T. Trinh; J. Glenn Songer; Stephen J. Billington
Group A streptococcus (GAS, Streptococcus pyogenes) is a strict human pathogen that causes severe, invasive diseases. GAS does not produce catalase, but has an ability to resist killing by reactive oxygen species (ROS) through novel mechanisms. The peroxide response regulator (PerR), a member of ferric uptake regulator (Fur) family, plays a key role for GAS to cope with oxidative stress by regulating the expression of multiple genes. Our previous studies have found that expression of an iron-binding protein, Dpr, is under the direct control of PerR. To elucidate the molecular interactions of PerR with its cognate promoter, we have carried out structural studies on PerR and PerR-DNA complex. By combining crystallography and small-angle X-ray scattering (SAXS), we confirmed that the determined PerR crystal structure reflects its conformation in solution. Through mutagenesis and biochemical analysis, we have identified DNA-binding residues suggesting that PerR binds to the dpr promoter at the per box through a winged-helix motif. Furthermore, we have performed SAXS analysis and resolved the molecular architecture of PerR-DNA complex, in which two 30 bp DNA fragments wrap around two PerR homodimers by interacting with the adjacent positively-charged winged-helix motifs. Overall, we provide structural insights into molecular recognition of DNA by PerR and define the hollow structural arrangement of PerR-30bpDNA complex, which displays a unique topology distinct from currently proposed DNA-binding models for Fur family regulators.
Hammel, Michal; Nix, Jay C.; Tseng, Hsiao-Ling; Tsou, Chih-Cheng; Fei, Chun-Hsien; Chiou, Huo-Sheng; Jeng, U-Ser; Lin, Yee-Shin; Chuang, Woei-Jer; Wu, Jiunn-Jong; Wang, Shuying
To establish a safer and more effective vaccine against pneumococcal respiratory infections, current knowledge regarding the antigens common among pneumococcal strains and improvements to the system for delivering these antigens across the mucosal barrier must be integrated. We developed a pneumococcal vaccine that combines the advantages of pneumococcal surface protein A (PspA) with a nontoxic intranasal vaccine delivery system based on a nanometer-sized hydrogel (nanogel) consisting of a cationic cholesteryl group-bearing pullulan (cCHP). The efficacy of the nanogel-based PspA nasal vaccine (cCHP-PspA) was tested in murine pneumococcal airway infection models. Intranasal vaccination with cCHP-PspA provided protective immunity against lethal challenge with Streptococcus pneumoniae Xen10, reduced colonization and invasion by bacteria in the upper and lower respiratory tracts, and induced systemic and nasal mucosal Th17 responses, high levels of PspA-specific serum immunoglobulin G (IgG), and nasal and bronchial IgA antibody responses. Moreover, there was no sign of PspA delivery by nanogel to either the olfactory bulbs or the central nervous system after intranasal administration. These results demonstrate the effectiveness and safety of the nanogel-based PspA nasal vaccine system as a universal mucosal vaccine against pneumococcal respiratory infection. PMID:23460513
Kong, Il Gyu; Sato, Ayuko; Yuki, Yoshikazu; Nochi, Tomonori; Takahashi, Haruko; Sawada, Shinichi; Mejima, Mio; Kurokawa, Shiho; Okada, Kazunari; Sato, Shintaro; Briles, David E; Kunisawa, Jun; Inoue, Yusuke; Yamamoto, Masafumi; Akiyoshi, Kazunari; Kiyono, Hiroshi
Vertebral osteomyelitis represents a diagnostic challenge to the clinician. Two cases of pyogenic vertebral osteomyelitis occurring weeks to months after a urinary tract infection with Escherichia coli are described. The rarity and subtle clinical presentation of this condition, the presence of pre-existing degenerative arthritic changes, and delayed appearance of radiologic signs of progression to destructive osteomyelitis contributed to a significant delay in diagnosis. Increased awareness of vertebral osteomyelitis as a clinical entity combined with information from radionuclide scanning may permit earlier detection of this condition. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4
Kern, R. Z.; Houpt, J. B.
The acquisition of superantigen-encoding genes by Streptococcus pyogenes has been associated with increased morbidity and mortality in humans, and the gain of four superantigens by Streptococcus equi is linked to the evolution of this host-restricted pathogen from an ancestral strain of the opportunistic pathogen Streptococcus equi subsp. zooepidemicus. A recent study determined that the culture supernatants of several S. equi subsp. zooepidemicus strains possessed mitogenic activity but lacked known superantigen-encoding genes. Here, we report the identification and activities of three novel superantigen-encoding genes. The products of szeF, szeN, and szeP share 59%, 49%, and 34% amino acid sequence identity with SPEH, SPEM, and SPEL, respectively. Recombinant SzeF, SzeN, and SzeP stimulated the proliferation of equine peripheral blood mononuclear cells, and tumor necrosis factor alpha (TNF-?) and gamma interferon (IFN-?) production, in vitro. Although none of these superantigen genes were encoded within functional prophage elements, szeN and szeP were located next to a prophage remnant, suggesting that they were acquired by horizontal transfer. Eighty-one of 165 diverse S. equi subsp. zooepidemicus strains screened, including 7 out of 15 isolates from cases of disease in humans, contained at least one of these new superantigen-encoding genes. The presence of szeN or szeP, but not szeF, was significantly associated with mitogenic activity in the S. equi subsp. zooepidemicus population (P < 0.000001, P < 0.000001, and P = 0.104, respectively). We conclude that horizontal transfer of these novel superantigens from and within the diverse S. equi subsp. zooepidemicus population is likely to have implications for veterinary and human disease.
Paillot, Romain; Darby, Alistair C.; Robinson, Carl; Wright, Nicola L.; Steward, Karen F.; Anderson, Emma; Webb, Katy; Holden, Matthew T. G.; Efstratiou, Androulla; Broughton, Karen; Jolley, Keith A.; Priestnall, Simon L.; Marotti Campi, Maria C.; Hughes, Margaret A.; Radford, Alan; Erles, Kerstin; Waller, Andrew S.
MyD88 is a key downstream adapter for most Toll-like receptors (TLRs) and interleukin-1 receptors (IL-1Rs). MyD88 deficiency in mice leads to susceptibility to a broad range of pathogens in experimental settings of infection. We describe a distinct situation in a natural setting of human infection. Nine children with autosomal recessive MyD88 deficiency suffered from life-threatening, often recurrent pyogenic bacterial infections, including invasive pneumococcal disease. However, these patients were otherwise healthy, with normal resistance to other microbes. Their clinical status improved with age, but not due to any cellular leakiness in MyD88 deficiency. The MyD88-dependent TLRs and IL-1Rs are therefore essential for protective immunity to a small number of pyogenic bacteria, but redundant for host defense to most natural infections.
von Bernuth, Horst; Picard, Capucine; Jin, Zhongbo; Pankla, Rungnapa; Xiao, Hui; Ku, Cheng-Lung; Chrabieh, Maya; Mustapha, Imen Ben; Ghandil, Pegah; Camcioglu, Yildiz; Vasconcelos, Julia; Sirvent, Nicolas; Guedes, Margarida; Vitor, Artur Bonito; Herrero-Mata, Maria Jose; Arostegui, Juan Ignacio; Rodrigo, Carlos; Alsina, Laia; Ruiz-Ortiz, Estibaliz; Juan, Manel; Fortuny, Claudia; Yague, Jordi; Anton, Jordi; Pascal, Mariona; Chang, Huey-Hsuan; Janniere, Lucile; Rose, Yoann; Garty, Ben-Zion; Chapel, Helen; Issekutz, Andrew; Marodi, Laszlo; Rodriguez-Gallego, Carlos; Banchereau, Jacques; Abel, Laurent; Li, Xiaoxia; Chaussabel, Damien; Puel, Anne; Casanova1, Jean-Laurent
We sequenced the genomes of 3,615 strains of serotype Emm protein 1 (M1) group A Streptococcus to unravel the nature and timing of molecular events contributing to the emergence, dissemination, and genetic diversification of an unusually virulent clone that now causes epidemic human infections worldwide. We discovered that the contemporary epidemic clone emerged in stepwise fashion from a precursor cell that first contained the phage encoding an extracellular DNase virulence factor (streptococcal DNase D2, SdaD2) and subsequently acquired the phage encoding the SpeA1 variant of the streptococcal pyrogenic exotoxin A superantigen. The SpeA2 toxin variant evolved from SpeA1 by a single-nucleotide change in the M1 progenitor strain before acquisition by horizontal gene transfer of a large chromosomal region encoding secreted toxins NAD(+)-glycohydrolase and streptolysin O. Acquisition of this 36-kb region in the early 1980s into just one cell containing the phage-encoded sdaD2 and speA2 genes was the final major molecular event preceding the emergence and rapid intercontinental spread of the contemporary epidemic clone. Thus, we resolve a decades-old controversy about the type and sequence of genomic alterations that produced this explosive epidemic. Analysis of comprehensive, population-based contemporary invasive strains from seven countries identified strong patterns of temporal population structure. Compared with a preepidemic reference strain, the contemporary clone is significantly more virulent in nonhuman primate models of pharyngitis and necrotizing fasciitis. A key finding is that the molecular evolutionary events transpiring in just one bacterial cell ultimately have produced millions of human infections worldwide. PMID:24733896
Nasser, Waleed; Beres, Stephen B; Olsen, Randall J; Dean, Melissa A; Rice, Kelsey A; Long, S Wesley; Kristinsson, Karl G; Gottfredsson, Magnus; Vuopio, Jaana; Raisanen, Kati; Caugant, Dominique A; Steinbakk, Martin; Low, Donald E; McGeer, Allison; Darenberg, Jessica; Henriques-Normark, Birgitta; Van Beneden, Chris A; Hoffmann, Steen; Musser, James M
We sequenced the genomes of 3,615 strains of serotype Emm protein 1 (M1) group A Streptococcus to unravel the nature and timing of molecular events contributing to the emergence, dissemination, and genetic diversification of an unusually virulent clone that now causes epidemic human infections worldwide. We discovered that the contemporary epidemic clone emerged in stepwise fashion from a precursor cell that first contained the phage encoding an extracellular DNase virulence factor (streptococcal DNase D2, SdaD2) and subsequently acquired the phage encoding the SpeA1 variant of the streptococcal pyrogenic exotoxin A superantigen. The SpeA2 toxin variant evolved from SpeA1 by a single-nucleotide change in the M1 progenitor strain before acquisition by horizontal gene transfer of a large chromosomal region encoding secreted toxins NAD+-glycohydrolase and streptolysin O. Acquisition of this 36-kb region in the early 1980s into just one cell containing the phage-encoded sdaD2 and speA2 genes was the final major molecular event preceding the emergence and rapid intercontinental spread of the contemporary epidemic clone. Thus, we resolve a decades-old controversy about the type and sequence of genomic alterations that produced this explosive epidemic. Analysis of comprehensive, population-based contemporary invasive strains from seven countries identified strong patterns of temporal population structure. Compared with a preepidemic reference strain, the contemporary clone is significantly more virulent in nonhuman primate models of pharyngitis and necrotizing fasciitis. A key finding is that the molecular evolutionary events transpiring in just one bacterial cell ultimately have produced millions of human infections worldwide.
Nasser, Waleed; Beres, Stephen B.; Olsen, Randall J.; Dean, Melissa A.; Rice, Kelsey A.; Long, S. Wesley; Kristinsson, Karl G.; Gottfredsson, Magnus; Vuopio, Jaana; Raisanen, Kati; Caugant, Dominique A.; Steinbakk, Martin; Low, Donald E.; McGeer, Allison; Darenberg, Jessica; Henriques-Normark, Birgitta; Van Beneden, Chris A.; Hoffmann, Steen; Musser, James M.
Background.?Streptococcus pneumoniae is a commensal colonizer of the human nasopharynx (NP) that causes disease after evasion of host defenses and dissemination. Pneumococcal strains expressing the newly identified serotype 11E arise from antigenically similar 11A progenitors by genetic inactivation of the O-acetyltransferase gene wcjE. Each 11E strain contains a distinct mutation to wcjE, suggesting that 11E strains are not transmitted among hosts despite their recovery from multiple patients with pneumococcal disease. We investigated whether the presumed lack of transmission of serotype 11E is consistent with its inability to survive in the NP. Methods.?More than 400 pneumococcal carriage, middle ear, conjunctiva, and blood isolates, serotyped as 11A by Quellung reaction, were reexamined for reactivity to 11A- and 11E-specific antibodies. We confirmed serotyping of isolates with sequencing of wcjE alleles. Results.?Serotype 11E strains were statistically more likely to occur among blood (4 of 15), conjunctiva (1 of 14), or middle ear (2 of 21) isolates than among carriage isolates (2 of 355). All 11E isolates contained unique mutations that putatively decrease wcjE expression. Conclusions.?The lack of a circulating 11E clone and the increased occurrence of 11E strains among disease isolates supports the idea that serotype 11E independently arises during infection after initial colonization with a serotype 11A progenitor. Factors encountered in the NP likely contribute to relative rarity of 11E among carriage isolates, whereas selective pressures in deeper tissues possibly promote 11E emergence. These findings illustrate a novel model of microevolution that transpires during the span of a single encounter with serotype 11A, highlighting the adaptability of bacterial pathogens within hosts.
Calix, Juan J.; Dagan, Ron; Pelton, Stephen I.; Porat, Nurith
The authors report a case of a 35-year-old man with no known underlying disease who presented with fever, cellulitis with hemorrhagic blebs on the left leg, monoarthricular left knee arthritis, multiple organ failure and septic shock. His clinical syndrome was compatible with toxic shock syndrome and his blood grew alpha hemolytic (viridians) Streptococcus mitis. To our knowledge, there are few reported cases of toxic shock syndrome cause by Streptococcus mitis in immune-competent adults. PMID:23682535
Intalapaporn, Poj; Wongcharoen, Sunee; Chinapha, Anongnart; Jariyasethpong, Tavatchai
Pyogenic granulomas and hemangiomas of oral cavity are well-known benign lesions. Although pyogenic granuloma is known to show a striking predilection for the gingiva and capillary hemangioma for lips, check, and tongue, palatal occurrence of these lesions is extremely rare. The clinical diagnosis of such an uncommon occurrence can be quite challenging as they sometimes may mimic more serious lesions such as malignancies. The purpose of this article is to report an unusual case of benign tumor occurring on hard palate which was clinically diagnosed as pyogenic granuloma and histopathologically as capillary hemangioma.
Rachappa, M. M.; Triveni, M. N.
Streptococcus anginosus is a member of the anginosus group streptococci, which form part of the normal human oral flora. In contrast to the pyogenic group streptococci, our knowledge of the virulence factors of the anginosus group streptococci, including S. anginosus, is not sufficient to allow a clear understanding of the basis of their pathogenicity. Generally, hemolysins are thought to be important virulence factors in streptococcal infections. In the present study, a sag operon homologue was shown to be responsible for beta-hemolysis in S. anginosus strains by random gene knockout. Interestingly, contrary to pyogenic group streptococci, beta-hemolytic S. anginosus was shown to have two tandem sagA homologues, encoding streptolysin S (SLS)-like peptides, in the sag operon homologue. Gene deletion and complementation experiments revealed that both genes were functional, and these SLS-like peptides were essential for beta-hemolysis in beta-hemolytic S. anginosus. Furthermore, the amino acid sequence of these SLS-like peptides differed from that of the typical SLS of S. pyogenes, especially in their propeptide domain, and an amino acid residue indicated to be important for the cytolytic activity of SLS in S. pyogenes was deleted in both S. anginosus homologues. These data suggest that SLS-like peptides encoded by two sagA homologues in beta-hemolytic S. anginosus may be potential virulence factors with a different structure essential for hemolytic activity and/or the maturation process compared to the typical SLS present in pyogenic group streptococci.
Tabata, Atsushi; Nakano, Kota; Ohkura, Kazuto; Tomoyasu, Toshifumi; Kikuchi, Ken; Whiley, Robert A.
The ten-pneumococcal conjugate vaccine (PCV10) was introduced into the national immunization program for childhood vaccination schedules by the Brazilian Health Public Service in March 2010. The aim of this study was to compare Streptococcus pneumoniae serotype distribution, antibiotic resistance patterns, and potential coverage before (January 2006-June 2010) and after (July 2010-September 2012) PCV10 introduction. The incidence of invasive pneumococcal disease (IPD), patient demographics, and disease characteristics were recorded. This study was conducted at the University Hospital of Sao Paulo University in Brazil from January 2006 to September 2012. Serotyping was performed using multiplex PCR typing, and antimicrobial sensitivity by Clinical and Laboratory Standards Institute (CLSI). A total of 259 S. pneumoniae strains were isolated from patients with IPD. The ages of the patients ranged from 3 months to 95 years old. The strains were isolated from cerebrospinal fluid, pleural fluid, and blood. The incidence of IPD among patients at HU-USP changed after the introduction of PCV10. The overall incidence of IPD was 3.42 cases per 1000 admissions in the vaccine pre- implementation period and of 2.99 cases per 1000 admissions in the vaccine post-implementation period. The incidence of IPD among children<2 y.o. attended at HU-USP changed significantly after the introduction of PCV10, from 20.30 to 3.97 of incidence. The incidence of PCV10- serotypes decrease from 16.47 to 0.44 in the same age, before and after PC10 implementation, respectively. Moreover, it was possible to realize the sensitivity to penicillin among isolates increased significantly in the post-vaccine period. Data from this study suggest that PCV10 contributed to decrease with PID rate among children less than 2 y.o. The resistance rate among pneumococcal isolates also could be observed since serotypes with greater resistance to beta lactam antibiotics were not easily isolated after vaccination. PMID:23747454
dos Santos, Silvia R; Passadore, Lilian F; Takagi, Elizabeth H; Fujii, Cristiane M; Yoshioka, Cristina R M; Gilio, Alfredo E; Martinez, Marina B
Streptococcus agalactiae (SA) is a Group B Streptococcus, which is a common pathogen implicated in neonatal and geriatric sepsis. Endogenous bacterial endophthalmitis (EBE) is a condition that results from haematogenous seeding of the globe, during transient or persistent bacteremia. We document a case of a non-septic geriatric patient, who developed EBE after a transient bacteraemia with SA. PMID:23814194
Saffra, Norman; Rakhamimov, Aleksandr; Husney, Robert; Ghitan, Monica
Pyogenic granuloma is thought to represent an exuberant tissue response to a local irritation or trauma. It is a reactional response to constant minor trauma and it might be related to hormonal changes. Clinically, these lesions usually present as single nodules or sessile papules with smooth or lobulated surfaces. These may be seen in any size, from a few millimetres to several centimetres. Pyogenic granuloma of the oral cavity is known to involve the gingiva more commonly (75% of all the cases). An extragingival occurrence of pyogenic granuloma is rare. This paper has described an extragingival pyogenic granuloma which occurred on the upper labial mucosa in a 30 years old female patient. PMID:23905151
K A, Kamala; Ashok, L; G P, Sujatha
A 47-year-old woman presented with a painful mass below her left medial canthus. Examination revealed a 1-cm tender, smooth, pulseless, mobile mass inferior to the level of the anterior lacrimal crest. CT imaging was performed. Excision of the involved angular vein revealed a smooth, intralumenal lesion. Histopathologic examination demonstrated intravenous pyogenic granuloma (IVPG). There are approximately 30 reported cases of IVPG in the English literature, 2 of which arise in the periocular angular vein. The ultrasound and MRI characteristics of IVPG have been previously described. We describe the CT profile of this rare, benign tumor as a mildly heterogeneic, contrast-enhancing cylindrical lesion within, and conforming to the shape of, the angular vein. There is dilatation of the vein proximal to the lesion with marked narrowing distal to it secondary to obstruction of flow. On noncontrast imaging, the lesion is isodense with nasal mucosa and without calcifications. PMID:19617809
Winn, Bryan J; Herreid, Peter A; Sires, Bryan S
Background Little is known about the population biology of Streptococcus pneumoniae in developing countries, although the majority of pneumococcal infections occur in this setting. The aim of the study was to apply MLST to investigate the population biology of S. pneumoniae in West Africa. Methods Seventy three invasive and carriage S. pneumoniae isolates from three West African countries including The Gambia, Nigeria and Ghana were investigated. The isolates covered seven serotypes (1, 3, 5, 6A, 11, 14, 23F) and were subjected to multilocus sequence typing and antibiotic susceptibility testing. Results Overall, 50 different sequence types (STs) were identified, of which 38% (29) were novel. The most common ST was a novel clone-ST 4012 (6.5%), and some clones including STs 913, 925, 1737, 2160 and 3310 appeared to be specific to the study region. Two STs including ST 63 and ST 4012 were associated with multiple serotypes indicating a history of serotype switching. ST 63 was associated with serotypes 3 and 23F, while ST 4012 was associated with serotypes 6A and 23. eBURST analyses using the stringent 6/7 identical loci definition grouped the 50 STs into 5 clonal complexes and 65 singletons, expressing a high level of genetic diversity among the isolates. Compared to the other serotypes, serotypes 1 and 5 isolates appeared to be more clonal. Internationally recognized antibiotic resistant clones of S. pneumoniae were generally absent in the population investigated and the only multidrug resistant isolate identified (1/66) belong to the Pneumocococcal Epidemiology Network clone ST 63. Conclusions The pneumococcal population in West Africa is quite divergent, and serotypes that are common in invasive disease (such as serotypes 1 and 5) are more likely to be clonal than serotypes that are common in carriage.
Donkor, Eric S.; Adegbola, Richard A.; Wren, Brendan W.; Antonio, Martin
Streptococcus pyogenes or group A Streptococcus (GAS) causes ~700 million human infections each year, resulting in over 500,000 deaths. The development of a commercial GAS vaccine is hampered due to high strain and serotype diversity in different geographical regions, and the generation of cross-reactive antibodies that may induce autoimmune disease. There is an urgent need to search for alternative vaccine candidates. High throughput multigenome data mining coupled with proteomics seems to be a promising approach to identify the universal vaccine candidates. In the present study, in silico analysis led to prediction of 147 proteins as universal vaccine candidates. Distribution pattern of these predicted candidates was explored in nonsequenced Indian GAS strains (n = 20) by using DNA array hybridization validating in silico analysis. High throughput analyses of surface proteins using 1D-SDS-PAGE coupled with ESI-LC-MS/MS was applied on highly (M49) and less (M1) invasive GAS strains of Indian origin. Comparative proteomics analysis revealed that highly invasive GAS M49 had metabolically more active membrane associated protein machinery than less invasive M1. Further, by overlapping proteomics data with in silico predicted vaccine candidate genes, 52 proteins were identified as probable universal vaccine candidates, which were expressed in these GAS serotypes. These proteins can further be investigated as universal vaccine candidates against GAS. Moreover, this robust approach may serve as a model that can be applied to identify the universal vaccine candidates in case of other pathogenic bacteria with high strain and genetic diversity. PMID:23181284
Sharma, Abhinay; Arya, Deepak Kumar; Sagar, Vivek; Bergmann, René; Chhatwal, Gursharan Singh; Johri, Atul Kumar
Group A streptococcus (GAS) is a human pathogen causing a wide repertoire of mild and severe diseases for which no vaccine is yet available. We recently reported the identification of three protein antigens that in combination conferred wide protection against GAS infection in mice. Here we focused our attention on the characterization of one of these three antigens, Spy0269, a highly conserved, surface-exposed, and immunogenic protein of unknown function. Deletion of the spy0269 gene in a GAS M1 isolate resulted in very long bacterial chains, which is indicative of an impaired capacity of the knockout mutant to properly divide. Confocal microscopy and immunoprecipitation experiments demonstrated that the protein was mainly localized at the cell septum and could interact in vitro with the cell division protein FtsZ, leading us to hypothesize that Spy0269 is a member of the GAS divisome machinery. Predicted structural domains and sequence homologies with known streptococcal adhesins suggested that this antigen could also play a role in mediating GAS interaction with host cells. This hypothesis was confirmed by showing that recombinant Spy0269 could bind to mammalian epithelial cells in vitro and that Lactococcus lactis expressing Spy0269 on its cell surface could adhere to mammalian cells in vitro and to mice nasal mucosa in vivo. On the basis of these data, we believe that Spy0269 is involved both in bacterial cell division and in adhesion to host cells and we propose to rename this multifunctional moonlighting protein as SpyAD (Streptococcus pyogenes Adhesion and Division protein).
Gallotta, Marilena; Gancitano, Giovanni; Pietrocola, Giampiero; Mora, Marirosa; Pezzicoli, Alfredo; Tuscano, Giovanna; Chiarot, Emiliano; Nardi-Dei, Vincenzo; Taddei, Anna Rita; Rindi, Simonetta; Speziale, Pietro; Soriani, Marco; Bensi, Giuliano
The human pathogen Group A Streptococcus (Streptococcus pyogenes, GAS) is widely recognized as a major cause of common pharyngitis as well as of severe invasive diseases and non-suppurative sequelae associated with the existence of GAS antigens eliciting host autoantibodies. It has been proposed that a subset of paediatric disorders characterized by tics and obsessive-compulsive symptoms would exacerbate in association with relapses of GAS-associated pharyngitis. This hypothesis is however still controversial. In the attempt to shed light on the contribution of GAS infections to the onset of neuropsychiatric or behavioral disorders affecting as many as 3% of children and adolescents, we tested the antibody response of tic patient sera to a representative panel of GAS antigens. In particular, 102 recombinant proteins were spotted on nitrocellulose-coated glass slides and probed against 61 sera collected from young patients with typical tic neuropsychiatric symptoms but with no overt GAS infection. Sera from 35 children with neither tic disorder nor overt GAS infection were also analyzed. The protein recognition patterns of these two sera groups were compared with those obtained using 239 sera from children with GAS-associated pharyngitis. This comparative analysis identified 25 antigens recognized by sera of the three patient groups and 21 antigens recognized by tic and pharyngitis sera, but poorly or not recognized by sera from children without tic. Interestingly, these antigens appeared to be, in quantitative terms, more immunogenic in tic than in pharyngitis patients. Additionally, a third group of antigens appeared to be preferentially and specifically recognized by tic sera. These findings provide the first evidence that tic patient sera exhibit immunological profiles typical of individuals who elicited a broad, specific and strong immune response against GAS. This may be relevant in the context of one of the hypothesis proposing that GAS antigen-dependent induction of autoantibodies in susceptible individuals may be involved the occurrence of tic disorders.
Bombaci, Mauro; Grifantini, Renata; Mora, Marirosa; Reguzzi, Valerio; Petracca, Roberto; Meoni, Eva; Balloni, Sergio; Zingaretti, Chiara; Falugi, Fabiana; Manetti, Andrea G. O.; Margarit, Immaculada; Musser, James M.; Cardona, Francesco; Orefici, Graziella; Grandi, Guido; Bensi, Giuliano
A retrospective study of extrapulmonary disease in 17 guinea pigs with Streptococcus pneumoniae infection showed the most common to be either chronic active or acute fibrinopurulent pericarditis, pleuritis or peritonitis, or all three. In periparturient f...
G. A. Parker R. J. Russell A. De Paoli
Group B Streptococcus commonly colonises healthy adults without symptoms, yet under certain circumstances displays the ability to invade host tissues, evade immune detection and cause serious invasive disease. Consequently, Group B Streptococcus remains a leading cause of neonatal pneumonia, sepsis and meningitis. Here we review recent information on the bacterial factors and mechanisms that direct host–pathogen interactions involved in the pathogenesis of Group B Streptococcus infection. New research on host signalling and inflammatory responses to Group B Streptococcus infection is summarised. An understanding of the complex interplay between Group B Streptococcus and host provides valuable insight into pathogen evolution and highlights molecular targets for therapeutic intervention.
Maisey, Heather C.; Doran, Kelly S.; Nizet, Victor
Streptococci have been considered to lack the classical SOS response, defined by increased mutation after UV exposure and regulation by LexA. Here we report the identification of a potential self-regulated SOS mutagenesis gene cassette in the Streptococcaceae family. Exposure to UV light was found to increase mutations to antibiotic resistance in Streptococcus uberis cultures. The mutational spectra revealed mainly G:C?A:T transitions, and Northern analyses demonstrated increased expression of a Y-family DNA polymerase resembling UmuC under DNA-damaging conditions. In the absence of the Y-family polymerase, S. uberis cells were sensitive to UV light and to mitomycin C. Furthermore, the UV-induced mutagenesis was almost completely abolished in cells deficient in the Y-family polymerase. The gene encoding the Y-family polymerase was localized in a four-gene operon including two hypothetical genes and a gene encoding a HdiR homolog. Electrophoretic mobility shift assays demonstrated that S. uberis HdiR binds specifically to an inverted repeat sequence in the promoter region of the four-gene operon. Database searches revealed conservation of the gene cassette in several Streptococcus species, including at least one genome each of Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus thermophilus strains. In addition, the umuC operon was localized in several mobile DNA elements of Streptococcus and Lactococcus species. We conclude that the hdiR-umuC-ORF3-ORF4 operon represents a novel gene cassette capable of mediating SOS mutagenesis among members of the Streptococcaceae.
Varhimo, Emilia; Savijoki, Kirsi; Jalava, Jari; Kuipers, Oscar P.; Varmanen, Pekka
Acute cholecystitis is a common inflammatory condition of the gallbladder caused most commonly by Escherichia coli, Enterococcus, and Klebsiella organisms. Streptococcus bovis is a Gram-positive, catalase-negative, anaerobic coccus found as a commensal inhabitant of the digestive system in 16% of healthy people. We report a rare case of acute cholecystitis caused by S bovis and discuss its implications with regard to the two known S bovis biotypes (I & II) both of which are associated with a number of other gastrointestinal diseases. PMID:23605823
Deering, Eoin McCarthy; Muravec, Zlatko; Castineira, Constantino Fiuza; O'Donoghue, Gerry
Arcanobacterium pyogenes, a common inhabitant of the mucosal surfaces of livestock, is also a pathogen associated with a variety of infections. In livestock, A. pyogenes is exposed to antimicrobial agents used for prophylaxis and therapy, notably tylosin, a macrolide used extensively for the prevention of liver abscessation in feedlot cattle in the United States. Many, but not all, tylosin-resistant A. pyogenes isolates carry erm(X), suggesting the presence of other determinants of tylosin resistance. Oligonucleotide primers designed for conserved regions of erm(B), erm(C), and erm(T) were used to amplify a 404-bp fragment from a tylosin-resistant A. pyogenes isolate, OX-7. DNA sequencing revealed that the PCR product was 100% identical to erm(B) genes, and the erm(B) gene region was cloned in Escherichia coli. The A. pyogenes Erm B determinant had the most DNA identity with an Erm B determinant carried by the Clostridium perfringens plasmid pIP402. However, the A. pyogenes determinant lacked direct repeat DR1 and contained a deletion in DR2. Flanking the A. pyogenes erm(B) gene were partial and entire genes similar to those found on the Enterococcus faecalis multiresistance plasmid pRE25. This novel architecture suggests that the erm(B) element may have arisen by recombination of two distinct genetic elements. Ten of 32 tylosin-resistant isolates carried erm(B), as determined by DNA hybridization, and all 10 isolates carried a similar element. Insertion of the element was site specific, as PCR and Southern blotting analysis revealed that the erm(B) element was inserted into orfY, a gene of unknown function. However, in three strains, this insertion resulted in a partial duplication of orfY.
Jost, B. Helen; Trinh, Hien T.; Songer, J. Glenn; Billington, Stephen J.
The genes responsible for cell wall biosynthesis and cell division (dcw genes) were identified and sequenced in Streptococcus pneumoniae. The genetic organization of the dcw cluster in Streptococcus pneumoniae differed significantly from the clusters of other bacteria reported to date. In particular, the genes corresponding to the 2 min region of the Escherichia coli chromosome were found distributed in three genetically separate regions of the Streptococcus pneumoniae chromosome. The first region contained the expected ftsA and ftsZ cell division genes at one end and pbp2b, ddl and murF at the other end. The murD, murG and divIB genes, always found located upstream of ftsA, were found in a second region separated from the first. A third region contained the yllC, yllD, pbp2x and mraY genes. The chromosomal region downstream of ftsZ was also sequenced and characterized. In Streptococcus pneumoniae this region contains four ORFs, all of unknown function, and an ORF encoding the Bacillus subtilis DivIVA homologue. The gene order and the organization of this region was found to be conserved in Staphylococcus aureus, Streptococcus pyogenes and Bacillus subtilis, raising the possibility that previously unidentified loci may also be involved in division. PMID:9846742
Massidda, O; Anderluzzi, D; Friedli, L; Feger, G
Primary hepatolithiasis (HL), recurrent pyogenic cholangitis, and oriental cholangiohepatitis are terms commonly used in Japan, Hong Kong, and Korea respectively, and describing the different aspects of the same disease, with "HL" indicating the pathologic changes, "recurrent pyogenic cholangitis" emphasizing the clinical presentation and suppurative inflammation, and "oriental cholangiohepatitis" highlighting its ethnic preference and mysterious nature. HL is predominantly a disease of the far east and shows great regional differences in the incidence and the type of intrahepatic stones. Pathologically, it is characterized by pigmented calcium bilirubinate stones within dilated intrahepatic bile ducts featuring chronic inflammation, mural fibrosis, and proliferation of peribiliary glands, without extrahepatic biliary obstruction. Episodes of suppurative inflammation cumulate in sclerosing cholangitis in peripheral ducts and parenchymal fibrosis from scarring and collapse. Mass-forming inflammatory pseudotumor and neoplasms-like intraductal papillary neoplasms and cholangiocarcinoma are increasingly recognized complications. Bacterial infection and dietary factors are believed to be important in the formation of pigment stones within intrahepatic bile ducts, whereas parasitic infestation is likely coincidental. With improvement of environmental conditions and westernization of diet, the incidence of pigment stones has decreased. At the same time, cholesterol stones with milder clinical manifestations and pathologic changes are increasingly recognized, and for which stone dissolution therapy can be considered. Understanding the underlying pathology avoids confusion with other diseases more prevalent in the western world, and allows correct selection of the appropriate treatment. PMID:21654363
Tsui, Wilson M S; Lam, Polly W Y; Lee, Wai-Ki; Chan, Yiu-Kay
Group A streptococcus (GAS, Streptococcus pyogenes) type emm1 is widely associated with streptococcal invasive disease. This type is prevalent worldwide but is rare in India. Instead, emm1-2 type which is closely related to emm1 but is a distinct type is more prevalent. Although emm1 has been well characterized, information available on emm1-2 is rare. In this study we present a comparative study of both types. DNA microarray analysis showed segregation of emm1 and emm1-2 isolates into two distinct clusters. Out of 229 arrayed genes, 83-87% were present, 6-9% absent and 4-8% genes were ambiguous in emm1 isolates. emm1-2 strains harboured only 68-77%, 11-13% were absent and 10-20% ambiguous genes. Fourteen genes, present in all emm1, were completely absent in the emm1-2 isolates. sfb1 is a gene which encodes for Streptococcal fibronectin binding adhesin and invasin which has restricted distribution among different emm types of GAS. A variant of sfb1 (sfb1-2) was the only gene which was present in all emm1-2 isolates, but absent from all emm1 strains. Sfb1 and Sfb1-2 differ in sequences in the aromatic domain and the proline rich repeat region, whereas the fibronectin binding region was conserved and exhibited similar fibronectin binding activity. The presence of Sfb1-2 in emm1-2 strains was concomitant with significantly higher fibronectin-binding and invasion efficiency of HEp-2 cells when compared to emm1 isolates. The role of Sfb1-2 in invasion was confirmed by latex bead assay. emm1-2 isolates follow membrane ruffling mechanism during invasion and intracellularly follow classical endocytic pathway. Further studies are required to understand the correlation between the presence of emm1-2 isolates and the disease pattern in North India. PMID:24856243
Sagar, Vivek; Bergmann, Rene; Nerlich, Andreas; McMillan, David J; Nitsche-Schmitz, D Patric; Fulde, Marcus; Talay, Susanne; Geffers, Robert; Hoe, Nancy; Kumar, Rajesh; Rohde, Manfred; Chakraborti, Anuradha; Chhatwal, Gursharan S
To investigate the antimicrobial resistance trends and the distribution of emm types of group A streptococci (GAS), we examined 1160 clinical isolates of GAS collected between 2003 and 2006. Susceptibilities to commonly used antimicrobial agents were determined by Etest, and macrolide resistance genes were detected by polymerase chain reaction (PCR). GAS isolates were typed by polymerase chain reaction PCR and
Athanasios G. Michos; Chrysanthi G. Bakoula; Maria Braoudaki; Foteini I. Koutouzi; Eleftheria S. Roma; Anastasia Pangalis; Georgia Nikolopoulou; Elena Kirikou; Vassiliki P. Syriopoulou
Aloe barbadensis Miller (or Aloe vera) has widespread use in health products, and despite numerous reports on the whole plant, little work has been performed on the inner gel, which has been used extensively in these products. This report describes the in vitro susceptibilities of two bacteria to this component. PMID:12604556
Ferro, Valerie A; Bradbury, Fiona; Cameron, Pamela; Shakir, Eisin; Rahman, Sabita R; Stimson, William H
A partial nucleotide sequence that included 1,693 base pairs of the M12 (emm12) gene of group A streptococci (strain CS24) and adjacent upstream DNA was determined. Type 12 M protein-specific mRNA of strain CS24 is transcribed from two promoters (P1 and P3) separated by 30 bases. The transcription start sites of the emm12 gene were located more than 400 bases downstream of a deletion that causes decreased M-protein gene transcription in strain CS64. Deletion analysis of M protein-expressing plasmids indicated that an upstream region greater than 1 kilobase is required for M-protein gene expression. The M-protein gene transcriptional unit appears to be monocistronic. Analysis of the emm12 DNA sequence revealed three major repeat regions. Two copies of each repeat, A and B, existed within the variable 5' end of the gene; repeat C demarcated the 5' end of the constant region shared by emm12 and emm6. Images
Robbins, J C; Spanier, J G; Jones, S J; Simpson, W J; Cleary, P P
Several mutations conferring resistance to streptomycin, kanamycin, spectinomycin, erythromycin, and lincomycin on the group A streptococcal strain 56188 have been mapped by two- and three-point crosses using transduction with bacteriophage A25. The markers are located in two linkage regions too distant to be cotransduced. One harbors the streptomycin and kanamycin loci which are transduced jointly at 78% and the other
The fate of /sup 125/I-labelled Streptolysin O injected intravenously into mice was studied. After 2 hours only 5% of the injected label remained in the blood. The highest concentration of radioactivity was consistently observed in the liver and kidneys. The labelled toxin was degraded in the liver but its greatest toxic effect took place in the kidneys.
Shibl, A.M.; Abdullah, M.E.; Al-Sowaygh, I.A.
Staphylococcus aureus showed decreased susceptibility to penicillin, vancomycin, sodium cephalothin and tetracycline, but increased susceptibility to sodium colistimethate, at a pressure of 68 atm in helium or helium-oxygen gas. Susceptibility of streptoc...
N. A. Schlamm
The regulation and control of gene expression in response to differing environmental stimuli is crucial for successful pathogen adaptation and persistence. The regulatory gene vru of Streptococcus uberis encodes a stand-alone response regulator with similarity to the Mga of group A Streptococcus. Mga controls expression of a number of important virulence determinants. Experimental intramammary challenge of dairy cattle with a mutant of S. uberis carrying an inactivating lesion in vru showed reduced ability to colonize the mammary gland and an inability to induce clinical signs of mastitis compared with the wild-type strain. Analysis of transcriptional differences of gene expression in the mutant, determined by microarray analysis, identified a number of coding sequences with altered expression in the absence of Vru. These consisted of known and putative virulence determinants, including Lbp (Sub0145), SclB (Sub1095), PauA (Sub1785) and hasA (Sub1696).
Egan, Sharon A.; Ward, Philip N.; Watson, Michael; Field, Terence R.
Thiamphenicol glycinate acetylcysteinate (TGA, CAS 20192-91-0) is a water soluble ester of thiamphenicol (TAP) that allows a rapid utilization by the systemic route but also a direct local action when used as aerosol. To assess the efficacy of aerosolized TGA in the treatment of experimental pneumonia in mice, we compared its in vivo activity with that of thiamphenicol glycinate hydrochloride (TG), erythromycin (ERT) and amoxicillin (AMX), the last two compounds being more active in vitro than TAP. TGA, administered by aerosol route, showed better efficacy than the aerosolized TG, particularly as far as survival rate is concerned, and was significantly more potent than ERT and similar to AMX either administered by oral route. No significantly different therapeutic efficacy was observed when TGA was parenterally administered. The rapid release, at the site of infection, of TAP and N-acetylcysteine and the favourable pharmacokinetic properties of TGA accounted in large part for its high therapeutic efficacy against Streptococcus pyogenes pneumonia. PMID:10442213
Albini, E; Arena, E; Belluco, G; Schioppacassi, G; Ungheri, D
INTRODUCTION Abiotrophia species have been referred to as nutritionally variant streptococci because of their fastidious nutritional requirements for growth. Abiotrophia species are difficult to identify with conventional solid culture. PRESENTATION OF CASE A 48-year-old woman was admitted to our hospital with severe low back pain and body temperature of 38.2 °C. Magnetic resonance imaging revealed edema and contrast enhancement of the L4 and L5 vertebral bodies with high signal intensity in the L3-4 and L4-5 intervertebral discs on the T2-weighted images. The patient underwent needle biopsy of the L3-4 disk. Cultures of disk biopsy samples and blood yielded gram positive cocci in short chains with scanty growth on chocolate agar. Further subculture with supplemented medium and subsequent 16S ribosomal RNA gene sequencing identified the pathogen as Abiotrhophia adiacens. The patient was treated with intravenous ampicillin. At 6-month follow-up, the patient was free of symptoms. DISCUSSION Causative microorganisms remain unidentified in 25–40% of spinal infection cases. Abiotrophia species grow poorly on conventional solid media, and require pyridoxal or thiol group supplementation. Use of Brucella HK agar or GAM agar plate is helpful for detection of Abiotrophia species. We first confirmed the diagnosis by direct identification of Abiotrophia adiacens from infected disk. Abiotrophia species are one of the major pathogens of infective endocarditis accounting for 5% of cases. Considering their fastidious nature, it is likely that most cases of Abiotrophia discitis are falsely classified as culture-negative discitis; therefore, their role in pyogenic discitis may be underestimated. CONCLUSION Subculture using nutritionally supplemented media is crucial for their identification.
Uehara, Kosuke; Chikuda, Hirotaka; Higurashi, Yoshimi; Ohkusu, Kiyofumi; Takeshita, Katsushi; Seichi, Atsushi; Tanaka, Sakae
A 65-year-old man presented with a 7-month history of eight bleeding periungual lesions on both feet. The clinical diagnosis of multiple pyogenic granulomas was confirmed by histological examination. Historically, the pyogenic granulomas appeared 3 months after commencing 5-fluorouracil chemotherapy for rectal carcinoma, suggesting a possible causative relationship. Chemotherapy was ceased by the supervising oncologist. Resolution occurred after two lesions had been treated with curettage and diathermy, and the remaining lesions with occlusive dressings over Kenacomb ointment (triamcinolone acetonide 0.1%, neomycin sulphate 0.25%, gramicidin 0.025%, nystatin 100,000 U/g) topically twice daily for a period of 3 months. PMID:16637811
Curr, Nathan; Saunders, Helen; Murugasu, Anand; Cooray, Prasad; Schwarz, Max; Gin, Douglas
Summary: Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a “coat of many colors,” enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.
Nobbs, Angela H.; Lamont, Richard J.; Jenkinson, Howard F.
The authors report a 13-month-old girl with chronic dacryocystitis, and history of three times probing and once inferior turbinate infracture. She underwent dacryocystorhinostomy due to failure of previous procedures. During surgery a free floating reddish mass was extracted from the lacrimal sac. Histopathologic examination revealed the mass to be a pyogenic granuloma. PMID:24215136
Bagheri, Abbas; Rafati, Nasrin; Salim, Reza Erfanian; Yazdani, Shahin
We report an unusual case of multiple pyogenic liver abscesses containing Ascariasis lumbricoides in a 35-year-old post-partum female who had delivered 1 month back. Open drainage of liver abscess along with liver worm was done. Patient did well post-operatively.
Hamid, Raashid; Wani, Sajad; Ahmad, Nawab; Akhter, Afrozah
Background Streptococcus dysgalactiae subsp. equisimilis (SDSE) causes invasive streptococcal infections, including streptococcal toxic shock syndrome (STSS), as does Lancefield group A Streptococcus pyogenes (GAS). We sequenced the entire genome of SDSE strain GGS_124 isolated from a patient with STSS. Results We found that GGS_124 consisted of a circular genome of 2,106,340 bp. Comparative analyses among bacterial genomes indicated that GGS_124 was most closely related to GAS. GGS_124 and GAS, but not other streptococci, shared a number of virulence factor genes, including genes encoding streptolysin O, NADase, and streptokinase A, distantly related to SIC (DRS), suggesting the importance of these factors in the development of invasive disease. GGS_124 contained 3 prophages, with one containing a virulence factor gene for streptodornase. All 3 prophages were significantly similar to GAS prophages that carry virulence factor genes, indicating that these prophages had transferred these genes between pathogens. SDSE was found to contain a gene encoding a superantigen, streptococcal exotoxin type G, but lacked several genes present in GAS that encode virulence factors, such as other superantigens, cysteine protease speB, and hyaluronan synthase operon hasABC. Similar to GGS_124, the SDSE strains contained larger numbers of clustered, regularly interspaced, short palindromic repeats (CRISPR) spacers than did GAS, suggesting that horizontal gene transfer via streptococcal phages between SDSE and GAS is somewhat restricted, although they share phage species. Conclusion Genome wide comparisons of SDSE with GAS indicate that SDSE is closely and quantitatively related to GAS. SDSE, however, lacks several virulence factors of GAS, including superantigens, SPE-B and the hasABC operon. CRISPR spacers may limit the horizontal transfer of phage encoded GAS virulence genes into SDSE. These findings may provide clues for dissecting the pathological roles of the virulence factors in SDSE and GAS that cause STSS.
A set of shuttle plasmids containing four different constitutive promoters was generated to facilitate overexpression of foreign and native genes in streptococci, such as Streptococcus mutans. The four promoters that were chosen were: P(ami), P(spac), P(23) and P(veg). These promoters are active in many Gram-positive bacteria, and allow various levels of gene expression depending on the host bacterium. Shuttle plasmids were constructed based on two types of broad-host-range replication origins: a rolling-circle replicon (pSH71) and a theta replicon (pAMbeta1). Shuttle plasmids derived from the pAMbeta1 replicon were generated to avoid the structural and segregational stability problems associated with rolling-circle replication, since these problems may be encountered during large gene cloning. In a complementation assay, we used one such plasmid to express a gene in trans to show the utility of these plasmids. In addition, a series of plasmids was generated for the expression of recombinant proteins with an N-terminal 6xHis tag or a C-terminal Strep-tag fusion, and, using a gene derived from S. mutans, we showed a high level of recombinant protein expression in S. mutans and Streptococcus pyogenes. Since these plasmids contain broad-host-range replication origins, and because the selected promoters are functional in many bacteria, they can be used for gene expression studies, such as complementation and recombinant protein expression. PMID:18667560
Biswas, Indranil; Jha, Jyoti K; Fromm, Nicholas
The genus Streptococcus comprises important pathogens that have a severe impact on human health and are responsible for substantial economic losses to agriculture. Here, we utilize 46 Streptococcus genome sequences (44 species), including eight species sequenced here, to provide the first genomic level insight into the evolutionary history and genetic basis underlying the functional diversity of all major groups of this genus. Gene gain/loss analysis revealed a dynamic pattern of genome evolution characterized by an initial period of gene gain followed by a period of loss, as the major groups within the genus diversified. This was followed by a period of genome expansion associated with the origins of the present extant species. The pattern is concordant with an emerging view that genomes evolve through a dynamic process of expansion and streamlining. A large proportion of the pan-genome has experienced lateral gene transfer (LGT) with causative factors, such as relatedness and shared environment, operating over different evolutionary scales. Multiple gene ontology terms were significantly enriched for each group, and mapping terms onto the phylogeny showed that those corresponding to genes born on branches leading to the major groups represented approximately one-fifth of those enriched. Furthermore, despite the extensive LGT, several biochemical characteristics have been retained since group formation, suggesting genomic cohesiveness through time, and that these characteristics may be fundamental to each group. For example, proteolysis: mitis group; urea metabolism: salivarius group; carbohydrate metabolism: pyogenic group; and transcription regulation: bovis group.
Richards, Vincent P.; Palmer, Sara R.; Pavinski Bitar, Paulina D.; Qin, Xiang; Weinstock, George M.; Highlander, Sarah K.; Town, Christopher D.; Burne, Robert A.; Stanhope, Michael J.
A set of shuttle plasmids containing four different constitutive promoters was generated to facilitate overexpression of foreign and native genes in streptococci, such as Streptococcus mutans. The four promoters that were chosen were: Pami, Pspac, P23 and Pveg. These promoters are active in many Gram-positive bacteria, and allow various levels of gene expression depending on the host bacterium. Shuttle plasmids were constructed based on two types of broad-host-range replication origins: a rolling-circle replicon (pSH71) and a theta replicon (pAM?1). Shuttle plasmids derived from the pAM?1 replicon were generated to avoid the structural and segregational stability problems associated with rolling-circle replication, since these problems may be encountered during large gene cloning. In a complementation assay, we used one such plasmid to express a gene in trans to show the utility of these plasmids. In addition, a series of plasmids was generated for the expression of recombinant proteins with an N-terminal 6×His tag or a C-terminal Strep-tag fusion, and, using a gene derived from S. mutans, we showed a high level of recombinant protein expression in S. mutans and Streptococcus pyogenes. Since these plasmids contain broad-host-range replication origins, and because the selected promoters are functional in many bacteria, they can be used for gene expression studies, such as complementation and recombinant protein expression.
Biswas, Indranil; Jha, Jyoti K.; Fromm, Nicholas
Background Streptococcus is an economically important genus as a number of species belonging to this genus are human and animal pathogens. The genus has been divided into different groups based on 16S rRNA gene sequence similarity. The variability observed among the members of these groups is low and it is difficult to distinguish them. The present study was taken up to explore 16S rRNA gene sequence to develop methods that can be used for preliminary identification and can supplement the existing methods for identification of clinically-relevant isolates of the genus Streptococcus. Methods 16S rRNA gene sequences belonging to the isolates of S. dysgalactiae, S. equi, S. pyogenes, S. agalactiae, S. bovis, S. gallolyticus, S. mutans, S. sobrinus, S. mitis, S. pneumoniae, S. thermophilus and S. anginosus were analyzed with the purpose to define genetic variability within each species to generate a phylogenetic framework, to identify species-specific signatures and in-silico restriction enzyme analysis. Results The framework based analysis was used to segregate Streptococcus spp. previously identified upto genus level. This segregation was validated using species-specific signatures and in-silico restriction enzyme analysis. 43 uncharacterized Streptococcus spp. could be identified using this approach. Conclusions The markers generated exploring 16S rRNA gene sequences provided useful tool that can be further used for identification of different species of the genus Streptococcus.
Arcanobacterium pyogenes, a common inhabitant of the upper respiratory and urogenital tracts of econom- ically important animals, such as cattle and swine, is also an opportunistic pathogen associated with suppu- rative infections in these animals. A. pyogenes expresses neuraminidase activity encoded by the nanH gene, and previously, construction of a nanH mutant of A. pyogenes BBR1 indicated that a second
B. Helen Jost; J. Glenn Songer; Stephen J. Billington
Hepatogastric fistula is very rare. We report a case of hepatogastric fistula as a complication of pyogenic liver abscess. A 40-year-old man presented with upper abdominal pain and high-grade fever of 2?weeks. Evaluation revealed multiple liver abscesses. On an empirical diagnosis of pyogenic liver abscess, he was treated with antibiotics. During hospital stay he developed intermittent large quantity bilious vomiting. Gastroduodenoscopy and contrast-enhanced CT of the abdomen showed rupture of left lobe liver abscess into the stomach. As expectant management failed to resolve the abscess, endoscopic retrograde papillotomy and stenting of common bile duct was performed. After endoscopic stenting, symptoms subsided. Imaging repeated after 2?weeks of endoscopic stenting showed resolving abscess. He was discharged and is doing well on regular follow-ups. We conclude that hepatogastricfistula can be managed by endoscopic stenting as bile flow through the stent hastens resolution and healing of the fistula. PMID:25035445
Gandham, Venkata Srinivas; Pottakkat, Biju; Panicker, Lakshmi C; Hari, Ranjit Vijaya
Tazarotene is a topically-applied, receptor-selective retinoid that has been shown to modulate several major pathogenic factors of psoriasis. Adverse effects are those of topical application of retinoids, the most common being mild to moderate burning, itching, stinging, and erythema, due to mild to moderate local skin irritation. While pyogenic granuloma-like lesions are a well recognized side effects of systemic retinoids, to our knowledge in the literature there is only one reported case of pyogenic granuloma (PG) following topical application of tazarotene for scalp psoriasis. In this paper we report 2 cases of periungual PGs following application of topical tazarotene and we present a review of the literature. PMID:24819765
Piraccini, B M; Venturi, M; Patrizi, A
\\u000a Streptococcus pneumoniae is a leading cause of community-acquired lower respiratory tract infections, sinusitis, meningitis, and bloodstream infections.\\u000a Pneumococci are Gram positive, encapsulated bacteria and exhibit more than 90 different capsular serotypes.\\u000a \\u000a Resistance to penicillin in clinical isolates was reported anecdotally as early as 1965, but was not considered a major concern\\u000a until the mid-1990s. In the 1990s, there was a
Mathias W. R. Pletz; Tobias Welte; Lesley McGee
The potentions of laser intravascular therapy in elimination of pyogenic and inflammatory intoxication in cases of acute pneumonia, pyo-destructive diseases (including posttraumatic diseases) of the lungs are studied clinically.
Kirillov, M. N.; Reshetnikov, V. A.; Kazhekin, O. A.; Shepelenko, A. F.
Hemorrhoidal banding is a well-established and safe outpatient procedure. Septic complications of hemorrhoidal banding are rare but can be fatal. The first case of pylephlebitis (septic portal vein thrombosis) and pyogenic liver abscess following hemorrhoidal banding in a 49-year-old man with diabetes is reported in the present study. Risk factors, management and the role of prophylaxis in immunocompromised patients are discussed. Caution against hemorrhoidal banding in immunosuppressed patients, including patients with diabetes, is warranted.
Chau, Nicole G; Bhatia, Sacha; Raman, Maitreyi
Pyogenic vertebral osteomyelitis responds well to conservative treatment at early stage, but more complicated and advanced conditions, including mechanical spinal instability, epidural abscess formation, neurologic deficits, and refractoriness to antibiotic therapy, usually require surgical intervention. The subject of using metallic implants in the setting of infection remains controversial, although more and more surgeons acknowledge that instrumentation can help the body to combat the infection rather than to interfere with it. The combination of radical debridement and instrumentation has lots of merits such as, restoration and maintenance of the sagittal alignment of the spine, stabilization of the spinal column and reduction of bed rest period. This issue must be viewed in the context of the overall and detailed health conditions of the subjecting patient. We think the culprit for the recurrence of infection is not the implants itself, but is the compromised general health condition of the patients. In this review, we focus on surgical treatment of pyogenic vertebral osteomyelitis with special attention to the role of spinal instrumentation in the presence of pyogenic infection.
Chen, Wei-Hua; Jiang, Lei-Sheng
Introduction The development of various benign oral mucosal lesions associated with dental implants, such as pyogenic granuloma or peripheral giant cell granuloma, has been rarely reported. However, the occurrence of vascular diseases, such as hemangioma, related to dental implants has not been explored in the literature. In this study, we report a case of co-development of pyogenic granuloma and capillary hemangioma on the alveolar ridge associated with a dental implant in a patient undergoing antithrombotic therapy. To the best of our knowledge, this is first case of hemangioma formation associated with a dental implant. Case presentation A 68-year-old Korean man was referred for intermittent bleeding and a dome-shaped overgrowing mass on his upper alveolar ridge. He underwent dental implantation 5 years ago, and was started on warfarin for cerebral infarction a year ago. He had experienced gum bleeding and gingival mass formation 6 months after warfarinization; then, his implant fixture was removed. However, his gingival mass has been gradually increasing. The gingival mass was surgically excised, and revealed the coexistence of pyogenic granuloma and capillary hemangioma in histological analysis of the specimen. The lesion has showed no recurrence for more than a year. Conclusions Regarding immunostaining features, the endothelial cell markers, CD34 and CD31, and the mesenchymal cell marker, vimentin, were strongly detected, but cell proliferation marker, Ki-67, was negatively expressed in the endothelial cells of the hemangioma portion. However, in the pyogenic granuloma portion, CD34 was almost negatively detected, whereas vimentin and Ki-67 were highly detected in the fibroblast-like tumor cells. According to these heterogeneous characteristics of the lesion, the patient was diagnosed with coexistence of pyogenic granuloma and capillary hemangioma associated with the dental implant on the attached gingiva. We recommend that patients with dental implants who have chronic peri-implantitis under antithrombotic therapy should be closely followed to ensure early detection of oral mucosal abnormalities.
Pyogenic Liver Abscess, Bacteremia, and Meningitis with Hypermucoviscous Klebsiella pneumoniae: An Unusual Case Report in a Human T-Cell Lymphotropic Virus Positive Patient of Caribbean Origin in the United States
Pyogenic liver abscess (PLA) is a potentially fatal disease. Klebsiella pneumoniae (K. pneumoniae) has replaced Escherichia coli (E. coli) as the predominant causative organism for pyogenic liver abscess. Over the years a unique form of community-acquired invasive K. pneumoniae infection of the liver has been well described in Southeast Asia. This has recently been linked to a virulent hypermucoviscous K. pneumoniae phenotype and to a specific genotype, rmpA positive. To our knowledge, we report the first case of PLA with bacteremia and meningitis in a Guyanese patient with the presence of rmpA-positive K. pneumoniae with laboratory evidence in North America.
Patel, Gargi; Shah, Neha
The use of immunoglobulins in the treatment of infectious diseases has a long tradition. Initially immunoglobulins from hyperimmunised animals were used for their antitoxic and antimicrobial activity. The development of preparations of human intravenous immunoglobulin (IVIG) and the observations of their long-term use enabled to assess their usefulness in the treatment of the diseases of proven or probable infectious etiology. In the treatment of infectious diseases IVIG are currently used as immunomodulating drugs or immunosuppressive therapy, more frequently than the specific antibodies against the viruses, bacteria or their toxins. In practice of the infectious ward IVIG are used as a drug of choice in the treatment of Kawasaki disease, in toxic epidermolysis and Stevens-Johnson syndrome. As adjunctive therapy IVIG are used in the infection with parvovirus B19, in hemophagocytic syndrome, for treatment of infections presenting with a severe toxemia caused by Clostridium difficile, Streptococcus pyogenes and Staphylococcus aureus. The rationale for the use of IVIG may be also serious infections caused by enteroviruses, particularly neuroinfections. The use of IVIG in the treatment of sepsis is controversial, since their effectiveness is not proven. PMID:21751556
Streptococcus pneumoniae (the pneumococcus) is an important human pathogen. Natural genetic transformation, which was discovered in this species, involves internalization of exogenous single-stranded DNA and its incorporation into the chromosome. It allows acquisition of pathogenicity islands and antibiotic resistance and promotes vaccine escape via capsule switching. This opinion article discusses how recent advances regarding several facets of pneumococcal transformation support the view that the process has evolved to maximize plasticity potential in this species, making the pneumococcus le transformiste of the bacterial kingdom and providing an advantage in the constant struggle between this pathogen and its host. PMID:24508048
Johnston, Calum; Campo, Nathalie; Bergé, Matthieu J; Polard, Patrice; Claverys, Jean-Pierre
Arcanobacterium pyogenes, a commensal on the mucous membranes of many economically important animal species, is also a pathogen, causing abscesses of the skin, joints, and visceral organs as well as mastitis and abortion. In food animals, A. pyogenes is exposed to antimicrobial agents used for growth promotion, prophy- laxis, and therapy, notably tylosin, a macrolide antibiotic used extensively for the
B. Helen Jost; Adam C. Field; Hien T. Trinh; J. Glenn Songer; Stephen J. Billington
Group A Streptococcus (GAS), the most frequent bacterial cause of suppurative infections in humans, expresses on the cell surface M proteins with capacity to bind factor H, FHL-1 and C4b binding protein (C4BP). This has been interpreted as a mechanism developed by this pathogen to decrease phagocytosis by macrophages and polymorphonuclear cells. We report the analysis of the capacity to bind factor H, FHL-1 and C4BP of 69 clinical isolates from 19 different serotypes. We show that strains binding complement regulators (30/69) belong to specific M serotypes. Of these, M18 strains are relatively frequent and interact with all three complement regulators simultaneously. However, the most virulent M1 and M3 strains did not bind complement regulators in our assays. The relevance of the interaction between complement regulators and S. pyogenes was analyzed using different approaches with the conclusion that under physiological conditions only FHL-1 and C4BP bind to streptococci. We show that FHL-1 presents a higher binding affinity for S. pyogenes than factor H because it carries a hydrophobic, high-affinity, GAS binding site in addition to the heparin binding site in SCR7. Using synthetic peptides we provide evidence that the high-affinity GAS binding site in FHL-1 involves the hydrophobic tail (Ser-Phe-Thr-Leu) that distinguishes FHL-1 from factor H. PMID:10760814
Pérez-Caballero, D; Albertí, S; Vivanco, F; Sánchez-Corral, P; Rodríguez de Córdoba, S
Considerations for a phase-III trial to evaluate a group B Streptococcus polysaccharide-protein conjugate vaccine in pregnant women for the prevention of early- and late-onset invasive disease in young-infants.
In 2010, an estimated 393,000 infection-related neonatal deaths occurred worldwide with Group B streptococcus (GBS) being a leading cause. Prevention of early-onset disease (0-6 days; EOD) is currently focused on intra-partum antibiotic prophylaxis to mothers identified as being at risk; such strategies reduce EOD by 75-80% but are resource-intensive and logistically-difficult to implement in developing countries. Vaccination of pregnant women is an alternate strategy for preventing both EOD and late-onset disease (7-89 days; LOD). A trivalent GBS polysaccharide-protein conjugate vaccine (GBS-CV) composed of capsular epitopes from serotypes Ia, Ib and III is undergoing phase-II evaluation among pregnant women in Europe, North America and Africa. These serotypes cause 70-80% of all invasive GBS disease in early-infancy. Maternal anti-GBS antibodies are associated with protection from EOD, however, since a correlate of efficacy has not been defined, a phase III efficacy trial may be required for licensure. Criteria for selecting appropriate sites include sufficiently high GBS incidence in large birth cohorts, as well as adequate clinical and microbiological diagnostic skills and capacities. Alternate pathways to licensure should be explored, e.g. identification of serological correlates of protection with subsequent phase IV studies establishing vaccine-effectiveness against invasive GBS disease. Conducting a randomized, placebo-controlled efficacy trial, however, has the additional advantage of also being able to evaluate the role of GBS contributing to neonatal culture-negative sepsis, stillbirths, prematurity and low-birth weight. PMID:23973347
Madhi, Shabir A; Dangor, Ziyaad; Heath, Paul T; Schrag, Stephanie; Izu, Alaine; Sobanjo-Ter Meulen, Ajoke; Dull, Peter M
The prevalence of dental caries in U.S. military populations is practically 100% and current caries prevention programs are inadequate. Dental caries is an infectious and transmissible disease and current evidence indicates that Streptococcus mutans is on...
H. J. Keene
Pyogenic granulomas (PGs) are benign vascular lesions occurring in skin and mucous membranes, often secondary to trauma or chronic inflammation. Oral PGs have never been described previously in hemophilia. We describe 2 pediatric patients with hemophilia A, who developed PGs with inadequate factor therapy for bleeding. PG pathophysiology suggests an association with hemophilia given chronic vascular damage and low-grade inflammation at sites of bleeding in hemophilia patients. Knowledge about the occurrence of PGs in hemophilia patients is essential for prompt diagnosis and early institution of factor therapy, which in turn allows more rapid cessation of bleeding and lesion involution. PMID:24663071
Lindsay, Holly; Srivaths, Lakshmi V
OBJECTIVE: The authors document changes in the etiology, diagnosis, bacteriology, treatment, and outcome of patients with pyogenic hepatic abscesses over the past 4 decades. SUMMARY BACKGROUND DATA: Pyogenic hepatic abscess is a highly lethal problem. Over the past 2 decades, new roentgenographic methods, such as ultrasound, computed tomographic scanning, direct cholangiography, guided aspiration, and percutaneous drainage, have altered both the diagnosis and treatment of these patients. A more aggressive approach to the management of hepatobiliary and pancreatic neoplasms also has resulted in an increased incidence of this problem METHODS: The records of 233 patients with pyogenic liver abscesses managed over a 42-year period were reviewed. Patients treated from 1952 to 1972 (n = 80) were compared with those seen from 1973 to 1993 (n = 153). RESULTS: From 1973 to 1993, the incidence increased from 13 to 20 per 100,000 hospital admissions (p < 0.01. Patients managed from 1973 to 1993 were more likely (p < 0.01) to have an underlying malignancy (52% vs. 28%) with most of these (81%) being a hepatobiliary or pancreatic cancer. The 1973 to 1993 patients were more likely (p < 0.05) to be infected with streptococcal (53% vs. 30%) or Pseudomonas (30% vs. 9%) species or to have mixed bacterial and fungal 26% vs. 1%) infections. The recent patients also were more likely (p < 0.05) to be managed by percutaneous abscess drainage (45% vs. 0%). Despite having more underlying problems, overall mortality decreased significantly (p < 0.01) from 65% (in 1952 to 1972 period) to 31% (in 1973 to 1993 period). The reduction was greatest for patients with multiple abscesses (88% vs. 44%; p < 0.05) with either a malignant or a benign biliary etiology (90% vs. 38%; p < 0.05). Mortality was increased (p < 0.02) in patients with mixed bacterial and fungal abscesses (50%). From 1973 to 1993, mortality was lower (p = 0.19) with open surgical as opposed to percutaneous abscess drainage (14% vs. 26%). CONCLUSIONS: Significant changes have occurred in the etiology, diagnosis, bacteriology, treatment, and outcome patients with pyogenic hepatic abscesses over the past 4 decades. However, mortality remains high, and proper management continues to be a challenge. Appropriate systemic antibiotics and fungal agents as well as adequate surgical, percutaneous, or biliary drainage are required for the best results.
Huang, C J; Pitt, H A; Lipsett, P A; Osterman, F A; Lillemoe, K D; Cameron, J L; Zuidema, G D
Respiratory ailments are important causes of morbidity and mortality in developing countries. Ethnobotanical surveys and literature reviews conducted in Guatemala during 1986-88 showed that 234 plants from 75 families, most of them of American origin, have been used for the treatment of respiratory ailments. Three Gram-positive bacteria causing respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes) were used to screen 68 of the most commonly used plants for activity. Twenty-eight of these (41.2%) inhibited the growth of one or more of the bacteria tested. Staphylococcus aureus was inhibited by 18 of the plant extracts, while 7 extracts were effective against Streptococcus pyogenes. Plants of American origin which exhibited antibacterial activity were: Gnaphalium viscosum, Lippia alba, Lippia dulcis, Physalis philadelphica, Satureja brownei, Solanum nigrescens and Tagetes lucida. These preliminary in vitro results provide scientific basis for the use of these plants against bacterial respiratory infections. PMID:2023428
Caceres, A; Alvarez, A V; Ovando, A E; Samayoa, B E
Serotype 6D of Streptococcus pneumoniae has been reported in Asia and the Fijian islands among nasopharyngeal carriage isolates. We now report a 6D isolate from a Finnish adult with invasive pneumococcal disease. Interestingly, the Finnish isolate and Asian isolate capsule gene loci are almost identical.
Nahm, M. H.; Oliver, M. B.; Siira, L.; Kaijalainen, T.; Lambertsen, L. M.; Virolainen, A.
A bacteriologically proven case of brain abscess, due to Streptococcus oralis is being reported in a 12-year-old girl who is a known case of congenital heart disease. The patient presented with fever, headache and vomiting. Pus cultures yielded S. oralis. PMID:24713909
Solanki, R; Subramanian, S; Lakshmi, V; Bhushanam, V; Kumar, A
nous population is five times that among the general popula- tion, and no single S. pyogenes clone has been shown to be dominant (5). We now report on the distribution of the genes for three erythrogenic toxins (speA, speB, and speC) and NA- Dase activity in GAS strains from the NT and from southwest- ern Sydney (SWS), a subtropical region.
Armando DelVecchio; Michael Maley; Bart J. Currie; K. S. Sriprakash
Streptococcus gordonii and Streptococcus mutans avidly colonize teeth. S. gordonii glucosyltransferase (GtfG) and amylase-binding proteins (AbpA\\/AbpB), and S. mutans glucosyltransferase (GtfB), affect their respective oral colonization abilities. We investigated their interrelationships and caries association in a rat model of human caries, examining the sequence of colonization and non- vs. high-sucrose diets, the latter being associated with aggressive decay in humans
J. M. Tanzer; A. Thompson; K. Sharma; M. M. Vickerman; E. M. Haase; F. A. Scannapieco
Spinal epidural abscess is a rare clinical entity, presenting insidiously with nonspecific clinical manifestations. The diagnosis is usually difficult and, if not made early, the consequences may be disastrous. The therapeutic strategy consists of surgical drainage and systemic antibiotherapy for 4 to 6 weeks; in carefully selected patients, the surgical intervention may be avoided. We describe the case of a diabetic woman who presented with a spinal epidural abscess due to Streptococcus equi subsp. zooepidemicus, a group C Streptococcus, treated successfully with parenteral antibiotherapy followed by oral antibiotherapy. Group C streptococci are bacteria typically associated with disease in animals, nowadays emerging as important human pathogens. This is the first reported case of spinal epidural abscess due to a Group C Streptococcus. PMID:17928789
Carragoso, Adelino; Capelo, Joana
Background Early-onset Group B haemolytic streptococcus infection (EOGBS) is an important cause of neonatal morbidity and mortality in the first week of life. Primary prevention of EOGBS is possible with intra-partum antibiotic prophylaxis (IAP.) Different prevention strategies are used internationally based on identifying pregnant women at risk, either by screening for GBS colonisation and/or by identifying risk factors for EOGBS in pregnancy or labour. A theoretical cost-effectiveness study has shown that a strategy with IAP based on five risk factors (risk-based strategy) or based on a positive screening test in combination with one or more risk factors (combination strategy) was the most cost-effective approach in the Netherlands. IAP for all pregnant women with a positive culture in pregnancy (screening strategy) and treatment in line with the current Dutch guideline (IAP after establishing a positive culture in case of pre-labour rupture of membranes or preterm birth and immediate IAP in case of intra-partum fever, previous sibling with EOGBS or GBS bacteriuria), were not cost-effective. Cost-effectiveness was based on the assumption of 100% adherence to each strategy. However, adherence in daily practice will be lower and therefore have an effect on cost-effectiveness. Method/Design The aims are to: a.) implement the current Dutch guideline, the risk-based strategy and the combination strategy in three pilot regions and b.) study the effects of these strategies in daily practice. Regions where all the care providers in maternity care implement the allocated strategy will be randomised. Before the introduction of the strategy, there will be a pre-test (use of the current guideline) involving 105 pregnant women per region. This will be followed by a post-test (use of the allocated strategy) involving 315 women per region. The outcome measures are: 1.) adherence to the specific prevention strategy and the determinants of adherence among care providers and pregnant women, 2.) outcomes in pregnant women and their babies and 3.) the costs of each strategy in relation to the effects. Discussion This study will provide recommendations for the implementation of the most cost-effective prevention strategy for EOGBS in the Netherlands on the basis of feasibility in daily practice. Trial registration Dutch Trial Register, NTR3965
Background Streptococcus intermedius is a member of the Streptococcus anginosus group. Clinical disease with S. intermedius is characterized by abscess formation and rarely endocarditis. Identification of Streptococcus intermedius is difficult, leading to the development of molecular methods to more accurately identify and characterize this organism. Case presentation Over a period of 6 months we encountered three cases of invasive Streptococcus intermedius infection presenting as hepatic abscesses, brain abscess, and endocarditis. We confirmed our microbiologic diagnosis through 16S sequencing and found a common virulence gene in each case. Conclusion Our report illustrates three different clinical manifestations due to Streptococcus intermedius infection that can be encountered in healthy individuals in a community hospital setting. To our knowledge, this is the first case of Streptococcus intermedius endocarditis confirmed by 16S sequencing analysis. The use of molecular methods may allow a better understanding of the epidemiology and pathogenesis of this organism.
Tran, MaryAnn P; Caldwell-McMillan, Molly; Khalife, Walid; Young, Vincent B
Endoscopic retrograde cholangiograms were studied in 52 patients with recurrent pyogenic cholangitis, a condition which is prevalent in Asia and in which there is a primary bacterial cholangitis. The earlier changes of recurrent pyogenic cholangitis were identified and found to be confined to the intrahepatic biliary tree. The left hepatic duct was more severely affected than the right hepatic duct and had a higher infestation by clonorchis. The severity of radiological changes correlated well with the duration of illness and the need for surgery. Gallstones were present in 34.2% of the patients and pancreatic ductal abnormality in 7.7%. The decision for surgery could be made early and accurately, and the type of surgery and the assignment of surgeons could be planned in advance--situations which conventional intravenous cholangiograms could not achieve. Cholangitis complicated endoscopic retrograde cholangiograms in 23.1% of the initial 26 patients without antibiotic cover but none of the subsequent 26 in whom this was used. PMID:648809
Lam, S K; Wong, K P; Chan, P K; Ngan, H; Ong, G B
Pyogenic arthritis of lumber spinal facet joints is an extremely rare condition. There are only 40 reported cases worldwide. Most cases were associated with history of paravertebral injection, which was not found in our patient. At the time of hospital admission, he had no abnormal magnetic resonance image findings. Two weeks later, he developed pyogenic facet joint arthritis associated with paravertebral and epidural abscess. This report is the first to describe delayed presentation of pyogenic arthritis associated with paravertebral abscess and epidural infection. PMID:22164319
Rhyu, Kee-Won; Park, Sang-Eun; Ji, Jong-Hun; Park, In; Kim, Young-Yul
Pyogenic granulomas are common, acquired, benign vascular lesions of the skin and mucous membranes that can develop both spontaneously and traumatically. We present a unique case of a four-year healthy, uncircumcised boy with multiple pyogenic granuloma on the mucous face of the penis foreskin. Although penile multiple pyogenic granulomas have previously been described in adults, there are no reports of similar problems in children. In this patient, the pathogenesis of the lesions is probably trauma related as reported in the anamnesis. Therapeutic options are discussed.
Di Giacomo, Martina; Bertocchini, Alessia; Loggini, Barbara; Pingitore, Raffaele
Pyothorax associated with a Mycoplasma sp and Arcanobacterium pyogenes was diagnosed at necropsy in a 1-month-old female Van kitten. The pleural cavity contained approximately 50 mL of blood-tinged, reddish-brown, nonodourous fluid bilaterally. Gram positive coccobacilli were seen in the exudate from necrotic plaques on the pleurae. Mycoplasma sp and A pyogenes were isolated from a sample of the fluid in the pleural cavity. The concomitant presence of Mycoplasma sp and A pyogenes could be considered another variation on the polymicrobial nature of pyothorax and associated pleural lesions in cats. PMID:12153057
Gulbahar, M Y; Gurturk, K
The effect of extracellular products from Streptococcus salivarius on sucrose-dependent adherence to smooth surfaces by other oral bacteria was studied in vitro. Strains of Streptococcus mitis, Streptococcus pyogenes, and Veillonella parvula without innate ability to adhere to a steel wire were able to do so when incubated with sucrose and cell-free culture fluid from S. salivarius strains 9759, 25975, CNII, and MEPI. These culture fluids synthesized more adherent material and water-insoluble glucan than those from Streptococcus mutans C67-1 and seven other S. salivarius strains. Among the S. salivarius strains, glucosyltransferase (GT; dextransucrase, EC 220.127.116.11) activity varied more than 100-fold. Cells of Veillonella and S. mitis S3 that had been incubated in culture fluids from S. salivarius 25975 and 9759, respectively, and then washed adhered upon subsequent incubation with sucrose. This was due to adsorbed GT because (i) the adherence was sensitive to dextranase; (ii) it was observed only with the high-GT culture fluids; (iii) it was dependent on sucrose; and (iv) the washed Veillonella cells synthesized glucan, but not fructan, from sucrose. These results suggest that sucrose-dependent adherence of bacteria without such innate ability can be mediated by (i) entrapment in insoluble glucan synthesized by S. salivarius culture fluids, and (ii) prior adsorption of GT from S. salivarius culture fluids. The possibility that GT formed by high-yield strains of S. salivarius is distributed through the mouth by the action of salivary flow and contributes to sucrose-dependent adherence and plaque formation is considered. Images
McCabe, R. M.; Donkersloot, J. A.
Lasers have opened a new door for the treatment of various disorders. Treatment of soft tissue intraoral mucosal growth by laser has profound effect on the patient acceptability taking the functional and aesthetic factor into consideration. The patient is able to get the outdoor treatment without the phobia of local anaesthetic and is out of the clinic in few minutes in contrast to the traditional method of surgical excision. Very few cases have been reported in literature regarding treatment of mucosal growth by soft tissue lasers. We present a case of recurrent pyogenic granuloma in a patient treated with an alternative approach, that is, diode laser, without the use of anaesthesia, sutures, anti-inflammatory drugs, or analgesics. The diagnosis of this lesion is equally important for correct treatment planning.
Rai, Shalu; Kaur, Mandeep; Bhatnagar, Puneet
Capsular serotypes and antimicrobial susceptibilities of Streptococcus pneumoniae causing invasive pneumococcal disease from 2009-2012 with an emphasis on serotype 19A in bacteraemic pneumonia and empyema and ?-lactam resistance.
Capsular serotypes and antimicrobial susceptibilities of Streptococcus pneumoniae isolates that cause invasive pneumococcal disease (IPD) were studied and the role of serotype 19A in the development of bacteraemic pneumonia and empyema was investigated. Subjects comprised 98 patients (56 adults and 42 children) who were treated for IPD at a university-affiliated tertiary referral centre in Taiwan during 2009-2012. Serotypes of the isolates were identified using the latex agglutination method. In vitro susceptibilities of the isolates to 13 antimicrobial agents were determined using the broth microdilution method and were interpreted as recommended by the Clinical and Laboratory Standards Institute. During the study period, bacteraemic pneumonia was the most common type of infection (43/98; 43.9%), followed by primary bacteraemia (30/98; 30.6%). Serotype 19A was the most common serotype (23/98; 23.5%) in all patients. Fourteen (70.0%) of 20 children (47.6% of all children) with serotype 19A infection had pneumonia with empyema, whilst eight patients had concomitant bacteraemia. 7-valent pneumococcal conjugated vaccine (PCV-7), PCV-10, PCV-13 and 23-valent pneumococcal polysaccharide vaccine (PPV-23) had coverage rates of 37.8%, 38.8%, 79.6% and 77.6%, respectively. A substantial increase in the proportion of serotype 15A (6.1%) and 6A (8.2%) was found. In addition, there was a significant reduction in rates of susceptibility of serotype 19A isolates to penicillin, cefotaxime and ceftriaxone but not to azithromycin or any quinolone tested compared with those of non-19A isolates. The prevalence of serotypes 19A, 15A and 6A in patients with IPD increased markedly during the period, especially in children with bacteraemic pneumonia and empyema. PMID:24071028
Lee, Meng-Rui; Chen, Chung-Ming; Chuang, Tzu-Yi; Huang, Yu-Tsung; Hsueh, Po-Ren
The relatedness of group A streptococcal (GAS) strains isolated from 35 Canadian patients with invasive disease of different severity was investigated by a variety of molecular methods. All patients were infected with M1T1 strains and, based on clinical criteria, were classified as severe (n = 21) and nonsevere (n = 14) invasive GAS infection cases. All the M1 strains studied had the emm1.0 allele and the same streptococcal pyrogenic exotoxin (Spe) genotype, speA+ speB+ speC speF+ speG+ speH smeZ+ ssa. All isolates had the same speA allotype, speA2. The randomly amplified polymorphic DNA banding pattern with two different primers was identical for all strains, and pulsed field gel electrophoresis analysis showed that 33 and 30 isolates had identical banding patterns after DNA digestion with SfiI or SmaI, respectively; the nonidentical isolates differed from the main pattern by only one band. A relatively high degree of polymorphism in specific regions of the sic gene was observed among isolates; however, this polymorphism was not associated with disease severity. Likewise, although the phenotypic expression of SpeA, SpeB, and SpeF proteins varied among the M1T1 isolates, there was no correlation between the amount of Spe expressed and disease severity. Importantly, mitogenic and cytokine responses induced by partially purified bacterial culture supernatants containing a mixture of expressed superantigens were very similar for isolates from severe and nonsevere cases (P > 0.1). Together, the data indicate that highly related invasive M1T1 isolates, some indistinguishable, can cause disease of varying severity in different individuals. These findings underscore the contribution of host factors to the outcome of invasive GAS infections.
Chatellier, Sonia; Ihendyane, Nahla; Kansal, Rita G.; Khambaty, Farukh; Basma, Hesham; Norrby-Teglund, Anna; Low, Donald E.; McGeer, Allison; Kotb, Malak
A streptococcus epidemic of moderate extent and severity was characterized by clinical symptoms different from the usual septic sore throat, though the organism found was culturally Streptococcus epidemicus. The infection was traced to the milk from a single quarter of the udder of a cow in a dairy of 112 cows producing an otherwise excellent grade of raw milk. A number of the milkers on the dairy farm were found infected. It was impossible to trace the infection of the cow's udder to any one of the milkers, though such an infection seems probable since the streptococcus isolated from the cow was in every respect like streptococci isolated from patients and milkers, and different from those usually found in normal cows or cows with garget. Certain recommendations are made to safeguard producers of raw milk against the occurrence of such epidemics.
Brown, J. Howard; Orcutt, Marion L.
Pyogenic liver abscess is a rarely seen extraintestinal complication of Crohn's disease. It has different features from other liver abscesses. Its clinical and laboratory findings are not specific and mimic the reactivation of Crohn's disease and diagnosis can be delayed. The radiological methods are very useful in diagnosis and treatment of liver abscess. In this paper, we present a patient with pyogenic liver abscess which developed in the course of Crohn's disease. PMID:15264121
Karaca, Cetin; Pinarba?i, Binnur; Danalio?lu, Ahmet; Akyüz, Filiz; Kaymako?lu, Sabahattin; Ozdil, Sadakat; Bozta?, Güngör; Mungan, Zeynel
Streptococcus pneumoniae frequently colonizes the upper respiratory tract of young children and is an important cause of otitis media and invasive disease. Carriage is more common than disease, yet the genetic factors that predispose a given clone for disease are not known. The relationship between capsule type, genetic background, and virulence is complex, and important questions remain regarding how pneumococcal
Melinda M. Pettigrew; Kristopher P. Fennie; Matthew P. York; Janeen Daniels; Faryal Ghaffar
Investigations on the Properties and Antigenic Structure of Streptococcus pluton. I. Morphological and Cultural Characteristics. II. Biochemical Properties and Pathogenicity (Badania nad Wlasciwosciami i Budowa Antygenowa Streptococcus pluton. I. Wlasciwosci Morfologiczne i Hodowlane. II. Wlasciwosci Biochemiczne i Chorobotworczosc).
Streptococcus pluton was isolated only from larvae showing clinical symptoms of European foulbrood (EFB) and from the caps of cells containing diseased larvae. For the isolation of S. pluton from material contaminated with accompanying bacterial flora med...
Members of the genus Streptococcus within the phylum Firmicutes are among the most diverse and significant zoonotic pathogens. This genus has gone through considerable taxonomic revision due to increasing improvements of chemotaxonomic approaches, DNA hybridization and 16S rRNA gene sequencing. It is proposed to place the majority of streptococci into "species groups". However, the evolutionary implications of species groups are not clear presently. We use comparative genomic approaches to yield a better understanding of the evolution of Streptococcus through genome dynamics, population structure, phylogenies and virulence factor distribution of species groups. Genome dynamics analyses indicate that the pan-genome size increases with the addition of newly sequenced strains, while the core genome size decreases with sequential addition at the genus level and species group level. Population structure analysis reveals two distinct lineages, one including Pyogenic, Bovis, Mutans and Salivarius groups, and the other including Mitis, Anginosus and Unknown groups. Phylogenetic dendrograms show that species within the same species group cluster together, and infer two main clades in accordance with population structure analysis. Distribution of streptococcal virulence factors has no obvious patterns among the species groups; however, the evolution of some common virulence factors is congruous with the evolution of species groups, according to phylogenetic inference. We suggest that the proposed streptococcal species groups are reasonable from the viewpoints of comparative genomics; evolution of the genus is congruent with the individual evolutionary trajectories of different species groups. PMID:24977706
Gao, Xiao-Yang; Zhi, Xiao-Yang; Li, Hong-Wei; Klenk, Hans-Peter; Li, Wen-Jun
Members of the genus Streptococcus within the phylum Firmicutes are among the most diverse and significant zoonotic pathogens. This genus has gone through considerable taxonomic revision due to increasing improvements of chemotaxonomic approaches, DNA hybridization and 16S rRNA gene sequencing. It is proposed to place the majority of streptococci into “species groups”. However, the evolutionary implications of species groups are not clear presently. We use comparative genomic approaches to yield a better understanding of the evolution of Streptococcus through genome dynamics, population structure, phylogenies and virulence factor distribution of species groups. Genome dynamics analyses indicate that the pan-genome size increases with the addition of newly sequenced strains, while the core genome size decreases with sequential addition at the genus level and species group level. Population structure analysis reveals two distinct lineages, one including Pyogenic, Bovis, Mutans and Salivarius groups, and the other including Mitis, Anginosus and Unknown groups. Phylogenetic dendrograms show that species within the same species group cluster together, and infer two main clades in accordance with population structure analysis. Distribution of streptococcal virulence factors has no obvious patterns among the species groups; however, the evolution of some common virulence factors is congruous with the evolution of species groups, according to phylogenetic inference. We suggest that the proposed streptococcal species groups are reasonable from the viewpoints of comparative genomics; evolution of the genus is congruent with the individual evolutionary trajectories of different species groups.
Gao, Xiao-Yang; Zhi, Xiao-Yang; Li, Hong-Wei; Klenk, Hans-Peter; Li, Wen-Jun
Background.?Zinc plays an important role in human immunity, and it is known that zinc deficiency in the host is linked to increased susceptibility to bacterial infection. In this study, we investigate the role of zinc efflux in the pathogenesis of Streptococcus pyogenes (group A Streptococcus [GAS]), a human pathogen responsible for superficial infections, such as pharyngitis and impetigo, and severe invasive infections. Methods.?The clinically important M1T1 wild-type strain was used in this study, and isogenic mutants were constructed with deletions in the czcD gene (Spy0653; which encodes a putative zinc efflux pump) and adjacent gczA gene (Spy0654; which encodes a putative zinc-dependent activator of czcD). Wild-type, isogenic mutants and complemented strains were tested for resistance against zinc stress, intracellular zinc accumulation, and virulence. Results.?Both czcD and gczA mutants exhibited increased sensitivity to zinc. Transcriptional analyses indicate that GczA upregulates czcD in response to zinc. Both mutants displayed increased susceptibility to human neutrophil killing and reduced virulence in a murine infection model. Furthermore, we showed that neutrophils mobilize zinc in response to GAS. Conclusions.?These data indicate that the innate immune system may use zinc as an antimicrobial agent and that zinc efflux is an important contributor to GAS pathogenesis. PMID:24449444
Ong, Cheryl-Lynn Y; Gillen, Christine M; Barnett, Timothy C; Walker, Mark J; McEwan, Alastair G
The direct binding of Streptococcus mitis to human platelets is mediated in part by two proteins (PblA and PblB) encoded by a lysogenic bacteriophage (SM1). Since SM1 is the first prophage of S. mitis that has been identified and because of the possible role of these phage-encoded proteins in virulence, we sought to characterize SM1 in greater detail. Sequencing of the SM1 genome revealed that it consisted of 34,692 bp, with an overall G+C content of 39 mol%. Fifty-six genes encoding proteins of 40 or more amino acids were identified. The genes of SM1 appear to be arranged in a modular, life cycle-specific organization. BLAST analysis also revealed that the proteins of SM1 have homologies to proteins from a wide variety of lambdoid phages. Bioinformatic analyses, in addition to N-terminal sequencing of the proteins, led to the assignment of possible functions to a number of proteins, including the integrase, the terminase, and two major structural proteins. Examination of the phage structural components indicates that the phage head may assemble using stable multimers of the major capsid protein, in a process similar to that of phage r1t. These findings indicate that SM1 may be part of a discrete subfamily of the Siphoviridae that includes at least phages r1t of Lactococcus lactis and SF370.3 of Streptococcus pyogenes.
Siboo, Ian R.; Bensing, Barbara A.; Sullam, Paul M.
Immunoelectrophoresis and electrophoresis have confirmed that acid-alcohol gamma extracts contained several type specific and non-specific protein antigens which were basic proteins. Their isoelectric point is above 8.5, while that of the non-type specifi...
R. Wahl J. Goichot G. Drach
Streptococcus salivarius is a common inhabitant of the oral mucosa that has been associated with infection in different sites (4). Meningeal infection by this species, generally related to neoplasias or iatrogenia, has been described on few occasions (1, 2, 6). We describe two cases recently diagnosed in our hospital. Case 1. An 84-year-old male was admitted for intestinal subocclusion due
Pedro Idigoras; Adoracion Valiente; Luis Iglesias; Patrick Trieu-Cuot; Claire Poyart
The genetic homogeneity among eight cariogenic strains of Streptococcus mutans was assessed by deoxyribonucleic acid (DNA)-DNA reassociation experiments. DNA species were extracted from strains GS5, Ingbritt, 10449, FA1, BHT, E49, SL1, and K1R. Labeled DN...
A. L. Coykendall
Streptococcus mutans is believed to be the prime etiologic agent of coronal caries in both humans and animals. It has been suggested that the cariogenicity (virulence) of S. mutans is due to the ability of the organism to adhere to the tooth surface, then...
S. Rosen I. Shklair E. X. Beck F. M. Beck
In this work, we purified and characterized a newly identified lantibiotic (salivaricin D) from Streptococcus salivarius 5M6c. Salivaricin D is a 34-amino-acid-residue peptide (3,467.55 Da); the locus of the gene encoding this peptide is a 16.5-kb DNA segment which contains genes encoding the precursor of two lantibiotics, two modification enzymes (dehydratase and cyclase), an ABC transporter, a serine-like protease, immunity proteins (lipoprotein and ABC transporters), a response regulator, and a sensor histidine kinase. The immunity gene (salI) was heterologously expressed in a sensitive indicator and provided significant protection against salivaricin D, confirming its immunity function. Salivaricin D is a naturally trypsin-resistant lantibiotic that is similar to nisin-like lantibiotics. It is a relatively broad-spectrum bacteriocin that inhibits members of many genera of Gram-positive bacteria, including the important human pathogens Streptococcus pyogenes and Streptococcus pneumoniae. Thus, Streptococcus salivarius 5M6c may be a potential biological agent for the control of oronasopharynx-colonizing streptococcal pathogens or may be used as a probiotic bacterium.
Birri, Dagim Jirata; Brede, Dag Anders
Men may not be able to multitask, but it is emerging that proteins can. This capacity of proteins to exhibit more than one function is termed protein moonlighting, and, surprisingly, many highly conserved proteins involved in metabolic regulation or the cell stress response have a range of additional biological actions which are involved in bacterial virulence. This review highlights the multiple roles exhibited by a range of bacterial proteins, such as glycolytic and other metabolic enzymes and molecular chaperones, and the role that such moonlighting activity plays in the virulence characteristics of a number of important human pathogens, including Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Helicobacter pylori, and Mycobacterium tuberculosis.
Henderson, Brian; Martin, Andrew
Arcanobacterium pyogenes, a commensal on the mucous membranes of many economically important animal species, is also a pathogen, causing abscesses of the skin, joints, and visceral organs as well as mastitis and abortion. In food animals, A. pyogenes is exposed to antimicrobial agents used for growth promotion, prophylaxis, and therapy, notably tylosin, a macrolide antibiotic used extensively for the prevention of liver abscessation in feedlot cattle in the United States. Of 48 A. pyogenes isolates, 11 (22.9%) exhibited inducible or constitutive resistance to tylosin (MIC of ?128 ?g/ml). These isolates also exhibited resistance to other macrolide and lincosamide antibiotics, suggesting a macrolide-lincosamide resistance phenotype. Of the 11 resistant isolates, genomic DNA from nine hybridized to an erm(X)-specific probe. Cloning and nucleotide sequencing of the A. pyogenes erm(X) gene indicated that it was >95% similar to erm(X) genes from Corynebacterium and Propionibacterium spp. Eight of the erm(X)-containing A. pyogenes isolates exhibited inducible tylosin resistance, which was consistent with the presence of a putative leader peptide upstream of the erm(X) open reading frame. For at least one A. pyogenes isolate, 98-4277-2, erm(X) was present on a plasmid, pAP2, and was associated with the insertion sequence IS6100. pAP2 also carried genes encoding the repressor-regulated tetracycline efflux system determinant Tet 33. The repA gene from pAP2 was nonfunctional in Escherichia coli and at least one A. pyogenes isolate, suggesting that there may be host-encoded factors required for replication of this plasmid.
Jost, B. Helen; Field, Adam C.; Trinh, Hien T.; Songer, J. Glenn; Billington, Stephen J.
Streptococcus pneumoniae is among the most significant causes of bacterial disease in humans. Here we report the 2,038,615-bp genomic sequence of the gram-positive bacterium S. pneumoniae R6. Because the R6 strain is avirulent and, more importantly, because it is readily transformed with DNA from homologous species and many heterologous species, it is the principal platform for investigation of the biology
JOANN HOSKINS; WILLIAM E. ALBORN; JEFFREY ARNOLD; LARRY C. BLASZCZAK; STANLEY BURGETT; BRADLEY S. DEHOFF; SHAWN T. ESTREM; LORI FRITZ; DONG-JING FU; WENDY FULLER; CHAD GERINGER; RAYMOND GILMOUR; JENNIFER S. GLASS; HAMID KHOJA; ANGELIKA R. KRAFT; ROBERT E. LAGACE; DONALD J. LEBLANC; LINDA N. LEE; ELLIOT J. LEFKOWITZ; JIN LU; PATTI MATSUSHIMA; SCOTT M. MCAHREN; MARGARET MCHENNEY; KEVIN MCLEASTER; CHRISTOPHER W. MUNDY; THALIA I. NICAS; FRANKLIN H. NORRIS; M. O'Gara; R. B. Peery; G. T. Robertson; P. Rockey; P.-M. Sun; M. E. Winkler; Y. Yang; M. Young-Bellido; G. Zhao; C. A. Zook; R. H. Baltz; S. R. Jaskunas; P. R. Rosteck; PAUL L. SKATRUD; JOHN I. GLASS
Transcranial Doppler ultrasound monitoring of cerebral blood flow velocity (CBFV) was performed on 17 children (age range 8 days to 6 years) with pyogenic meningitis. Serial measurements of the peak systolic, end diastolic, mean flow velocity, and resistance index (equal to peak systolic velocity minus end diastolic velocity divided by peak systolic velocity) were obtained over the period of their hospital admission. In all 16 survivors there was a significant decrease in the final resistance index compared with the initial resistance index due to a significant increase in the end diastolic velocity. There was a significant increase in the final mean flow velocity. In four patients the decrease in intracranial pressure and increase in cerebral perfusion pressure after mannitol infusions was accompanied by a corresponding decrease in resistance index and increase in mean flow velocity. A pressure passive CBFV response with a significant linear correlation for resistance index/mean arterial pressure may suggest a loss of cerebrovascular autoregulation. These results suggest that in the early phase increased cerebrovascular resistance may contribute to a relative impairment of cerebral perfusion. Non-invasive monitoring by transcranial Doppler ultrasound may be helpful for early detection of deterioration in cerebral haemodynamic trends.
Goh, D; Minns, R A
In this report the authors describe a rare case of a fulminant, pyogenic, necrotizing infection of the spinal cord and brain. Necrotizing lesions of the brain and spinal cord are usually infectious in origin and are associated with high rates of morbidity and death. Although the pathogens responsible have been identified in a few instances, the causal factors remain unknown in many cases. An 11-year-old girl developed acute, rapidly progressive paraplegia with bladder involvement and sensory loss below T-10. She had been treated recently for a Staphylococcus aureus infection of the knee joint precipitated by a penetrating injury with organic matter in the aftermath of a cyclone. Although appropriate antibiotic therapy was instituted, the spinal cord infection progressed to involve the entire spinal cord, brainstem, and brain. This fulminant course was marked by a rapid deterioration in the patient's clinical condition, ultimately leading to her death. Magnetic resonance imaging demonstrated a previously undescribed pattern of longitudinal enhancement along the spinal cord, as well as the white matter tracts in the brainstem and brain. The possible route of spread of infection along the neuraxis is postulated to be the potential space along the white matter tracts. Treatment is not standardized due to the rarity of the condition. PMID:23495810
Madhugiri, Venkatesh Shankar; Gundamaneni, Sudheer Kumar; Santosh, Vani; Jagadisan, Barath; Sasidharan, Gopalakrishnan Madhavan; Roopesh-Kumar, Rathakrishnan V; Yadav, Awdhesh Kumar; Singh, Manish; Ananthakrishnan, Ramesh; Pariarath, Nisha; Biswal, Niranjan
Background Streptococcus mutans is the major pathogen of dental caries, and it occasionally causes infective endocarditis. While the pathogenicity of this species is distinct from other human pathogenic streptococci, the species-specific evolution of the genus Streptococcus and its genomic diversity are poorly understood. Results We have sequenced the complete genome of S. mutans serotype c strain NN2025, and compared it with the genome of UA159. The NN2025 genome is composed of 2,013,587 bp, and the two strains show highly conserved core-genome. However, comparison of the two S. mutans strains showed a large genomic inversio