scholarly journals A Novel Integrative Conjugative Element Mediates Genetic Transfer from Group G Streptococcus to Other β-Hemolytic Streptococci

2009 ◽  
Vol 191 (7) ◽  
pp. 2257-2265 ◽  
Author(s):  
Mark R. Davies ◽  
Josephine Shera ◽  
Gary H. Van Domselaar ◽  
Kadaba S. Sriprakash ◽  
David J. McMillan
Keyword(s):  
Group A Streptococcus ◽  
Bacterial Species ◽  
Group B Streptococcus ◽  
Gene Clusters ◽  
Kanamycin Resistance ◽  
Open Reading Frames ◽  
Cadmium Resistance ◽  
Integrative Conjugative Element ◽  
Group B ◽  
Reading Frames

ABSTRACT Lateral gene transfer is a significant contributor to the ongoing evolution of many bacterial pathogens, including β-hemolytic streptococci. Here we provide the first characterization of a novel integrative conjugative element (ICE), ICESde3396, from Streptococcus dysgalactiae subsp. equisimilis (group G streptococcus [GGS]), a bacterium commonly found in the throat and skin of humans. ICESde3396 is 64 kb in size and encodes 66 putative open reading frames. ICESde3396 shares 38 open reading frames with a putative ICE from Streptococcus agalactiae (group B streptococcus [GBS]), ICESa2603. In addition to genes involves in conjugal processes, ICESde3396 also carries genes predicted to be involved in virulence and resistance to various metals. A major feature of ICESde3396 differentiating it from ICESa2603 is the presence of an 18-kb internal recombinogenic region containing four unique gene clusters, which appear to have been acquired from streptococcal and nonstreptococcal bacterial species. The four clusters include two cadmium resistance operons, an arsenic resistance operon, and genes with orthologues in a group A streptococcus (GAS) prophage. Streptococci that naturally harbor ICESde3396 have increased resistance to cadmium and arsenate, indicating the functionality of genes present in the 18-kb recombinogenic region. By marking ICESde3396 with a kanamycin resistance gene, we demonstrate that the ICE is transferable to other GGS isolates as well as GBS and GAS. To investigate the presence of the ICE in clinical streptococcal isolates, we screened 69 isolates (30 GGS, 19 GBS, and 20 GAS isolates) for the presence of three separate regions of ICESde3396. Eleven isolates possessed all three regions, suggesting they harbored ICESde3396-like elements. Another four isolates possessed ICESa2603-like elements. We propose that ICESde3396 is a mobile genetic element that is capable of acquiring DNA from multiple bacterial sources and is a vehicle for dissemination of this DNA through the wider β-hemolytic streptococcal population.

scholarly journals The Relevance of IL-1-Signaling in the Protection against Gram-Positive Bacteria

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 132
Author(s):  
Angelina Midiri ◽  
Giuseppe Mancuso ◽  
Concetta Beninati ◽  
Elisabetta Gerace ◽  
Carmelo Biondo
Keyword(s):  
Host Defense ◽  
Group A Streptococcus ◽  
Bacterial Species ◽  
Interleukin 1 ◽  
Group B Streptococcus ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Group A ◽  
Group B ◽  
Deficient Mice

Previous studies performed using a model of group B streptococcus (GBS)-induced peritoneal inflammation indicate that the interleukin-1 receptor (IL-1R) family plays an important role in the innate host defense against this encapsulated Gram-positive bacteria. Since the role of IL-1-dependent signaling in peritoneal infections induced by other Gram-positive bacteria is unknown, in the present study we sought to investigate the contribution of IL-1R signaling in host defenses against Streptococcus pyogenes (group A streptococcus or GAS) or Staphylococcus aureus, two frequent and global human Gram-positive extracellular pathogens. We analyzed here the outcome of GAS or S. aureus infection in IL-1R-deficient mice. After inoculated intraperitoneal (i.p.) inoculation with group A Streptococcus or S. aureus, all the wild-type (WT) control mice survived the challenge, while, respectively, 63% or 50% of IL-1-defective mice died. Lethality was due to the ability of both bacterial species to replicate and disseminate to the target organs of IL-1R-deficient mice. Moreover, the experimental results indicate that IL-1 signaling promotes the production of leukocyte attractant chemokines CXCL-1 and CXCL-2 and recruitment of neutrophils to bacterial infection sites. Accordingly, the reduced neutrophil recruitment in IL-1R-deficient mice was linked with decreased production of neutrophil chemokines. Collectively, our findings indicate that IL-1 signaling, as previously showed in host defense against GBS, plays a fundamental role also in controlling the progression and outcome of GAS or S. aureus disease.

An Emerging Infection: Streptococcal Toxic Shock-Like Syndrome Caused By Group B Streptococcus (GBS), Streptococcus Agalactiae

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S140-S140
Author(s):  
F Rajack ◽  
A Afsari ◽  
A M Ramadan ◽  
T J Naab
Keyword(s):  
Soft Tissue ◽  
Necrotizing Fasciitis ◽  
Streptococcus Agalactiae ◽  
Group A Streptococcus ◽  
Multiorgan Failure ◽  
Group B Streptococcus ◽  
Stage Iii ◽  
Streptococcal Toxic Shock Syndrome ◽  
Toxic Shock ◽  
Group B

Abstract Introduction/Objective Streptococcus agalactiae, Group B Streptococcus (GBS), is a major cause of neonatal sepsis and infections in pregnant women. However, incidence of invasive GBS infections has more than doubled in the last two decades with highest risk in adults 65 years or older. Other risk factors are diabetes, malignancy, and immunocompromised state. Bacteremia and skin soft tissue infections are the most common invasive infections in nonpregnant adults. Rarely GBS infection has a fulminating pyrogenic exotoxin-mediated course characterized by acute onset, multiorgan failure, shock, and sometimes death, referred to as toxic shock-like syndrome. Methods A 77-year-old hypertensive female with uncontrolled type 2 diabetes mellitus and a history of bilateral foot ulcers presented to the hospital in probable septic shock. Clinical diagnosis of necrotizing fasciitis was made and she underwent bilateral lower limb amputations. Results Grossly soft tissue appeared gray. Microscopically fascia was necrotic without neutrophils present and Gram stain revealed sheets of Gram positive cocci. These findings reflected histopathologic Stage III necrotizing fasciitis, which is associated with 47% mortality. Autopsy showed a similar histology of Stage III necrotizing fasciitis involving the surgical stump. Erythema and desquamation of the upper limbs bilaterally and multi-organ failure met the clinical picture of Streptococcal Toxic Shock Syndrome (STSS) and fulfilled the criteria for TSS due to Group A Streptococcus (GAS), defined by The Working Group on Severe Streptococcal Infections. Conclusion Group B Streptococcal Toxic Shock-Like Syndrome may have a similar outcome to STSS caused by GAS and other pathogens and, in limited studies, mortality has been 30% or greater.

STUDIES ON INTERACTION OF BACTERIA, SERUM FACTORS AND POLYMORPHONUCLEAR LEUKOCYTES IN MOTHERS AND NEWBORNS

PEDIATRICS ◽  
1969 ◽  
Vol 44 (1) ◽  
pp. 49-57 ◽  
Author(s):  
John H. Dossett ◽  
Ralph C. Williams ◽  
Paul G. Quie
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Bacterial Species ◽  
Group B Streptococcus ◽  
Newborn Infants ◽  
Maternal Serum ◽  
Humoral Factors ◽  
Serum Factors ◽  
E Coli ◽  
Serum Fractions ◽  
Group B

The bactericidal capacity of newborn infants' whole blood for E. coli was deficient compared to the mothers, and attempts were made to identify cellular or humoral factors responsible for this deficiency. Separated polymorphonuclear leukocytes from newborn infants were found to be similar to polymorphs from mothers in capacity to engulf and kill E. coli and other bacteria so that cellular deficiency was not evident. Comparison of the serum opsonic capacity of newborn infants' and mothers' sera revealed deficient opsonic capacity for E. coli in newborn sera. The mean opsonic titer for E. coli was 46.7 in mothers and 4.3 in neonates. Serum opsonic titers for Staph. aureus and group B streptococcus were similar. The opsonic capacity for all bacterial species was decreased when the sera were heated or decomplemented with immune complexes indicating the phagocytosis amplifying role of complement. The newborn-maternal difference in opsonic capacity for E. coli was presumably a result of deficient 19S antibodies, the primary opsonic antibodies for this organism. Maternal 19S serum fractions alone, however, showed no opsonic capacity for E. coli. Addition of a complement source (newborn serum absorbed with E. coli) revealed the opsonic capacity of these 19S maternal serum fractions for E. coli. Antibodies in 19S serum fractions therefore are efficient opsonins for E. coli; however, complement is necessary to demonstrate their opsonic potential.

scholarly journals Genetic Characterization and Evolutionary Implications of a car Gene Cluster in the Carbazole Degrader Pseudomonas sp. Strain CA10

2001 ◽  
Vol 183 (12) ◽  
pp. 3663-3679 ◽  
Author(s):  
Hideaki Nojiri ◽  
Hiroyo Sekiguchi ◽  
Kana Maeda ◽  
Masaaki Urata ◽  
Sei-Ichiro Nakai ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Insertion Sequence ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
The Novel ◽  
Gene Duplications ◽  
Homology Searching ◽  
Reading Frames ◽  
Strain Ca10 ◽  
Recombination Gene

ABSTRACT The nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of thecarAaAaBaBbCAc(ORF7)Ad genes of carbazole-degrading Pseudomonas sp. strain CA10 were determined. Thirty-two open reading frames (ORFs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (carAaAaBaBbCAcAdDFE) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. The high identities (68 to 83%) with the enzymes involved in 3-(3-hydroxyphenyl)propionic acid degradation were observed only for CarFE. This observation, together with the fact that two ORFs are inserted between carDand carFE, makes it quite likely that thecarFE genes were recruited from another locus. In the 21-kb region upstream from carAa, aromatic-ring-hydroxylating dioxygenase genes (ORF26, ORF27, and ORF28) were found. Inductive expression in carbazole-grown cells and the results of homology searching indicate that these genes encode the anthranilate 1,2-dioxygenase involved in carbazole degradation. Therefore, these ORFs were designated antABC. Four homologous insertion sequences, IS5car1 to IS5car4, were identified in the neighboring regions ofcar and ant genes. IS5car2and IS5car3 constituted the putative composite transposon containing antABC. One-ended transposition of IS5car2 together with the 5′ portion ofantA into the region immediately upstream ofcarAa had resulted in the formation of IS5car1 and ORF9. In addition to the insertion sequence-dependent recombination, gene duplications and presumed gene fusion were observed. In conclusion, through the above gene rearrangement, the novel genetic structure of the cargene cluster has been constructed. In addition, it was also revealed that the car and ant gene clusters are located on the megaplasmid pCAR1.

Analysis of high CO2 requiring mutants indicates a central role for the 5′ flanking region of rbc and for the carboxysomes in cyanobacterial photosynthesis

1990 ◽  
Vol 68 (6) ◽  
pp. 1303-1310 ◽  
Author(s):  
Aaron Kaplan
Keyword(s):  
Inorganic Carbon ◽  
Quantitative Model ◽  
Photosynthetic Performance ◽  
Kanamycin Resistance ◽  
Open Reading Frames ◽  
Bisphosphate Carboxylase ◽  
Insertional Inactivation ◽  
Flanking Region ◽  
Inorganic Carbon Transport ◽  
Reading Frames

The mutants E1 and O221, isolated from Synechococcus sp. PCC7942, exhibit a very low apparent photosynthetic affinity for both extracellular and intracellular inorganic carbon and hence require high CO2 concentrations for growth. These mutants possess defective carboxysomes, but the activity of ribulose 1,5-bisphosphate carboxylase is normal. The mutations in these mutants have been mapped to the 5′-flanking region of rbc, and two open reading frames, the functions of which are not yet known, have been identified in this region. Insertional inactivation (by inserting a kanamycin-resistance cartridge) of one of these open reading frames, where the mutation in O221 is located, resulted in a new high CO2 requiring phenotype. This mutant contains defective carboxysomes similar to those of O221. The role of the rbc and its 5′-flanking region in the photosynthetic performance of cyanobacteria and the structural organization of the carboxysomes are discussed in view of our recently proposed quantitative model for inorganic carbon transport and photosynthesis in cyanobacteria.

Variability of neuD transcription levels and capsular sialic acid expression among serotype III group B Streptococcus strains

Microbiology ◽  
2011 ◽  
Vol 157 (12) ◽  
pp. 3282-3291 ◽  
Author(s):  
Marie-Frédérique Lartigue ◽  
Agnès Fribourg Poulard ◽  
Rim Al Safadi ◽  
Hélène Pailhories ◽  
Anne-Sophie Domelier-Valentin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Sialic Acid ◽  
Growth Phase ◽  
Exponential Growth ◽  
Bacterial Species ◽  
Group B Streptococcus ◽  
Neonatal Meningitis ◽  
Exponential Growth Phase ◽  
Growth Phases ◽  
Group B

Serotype III group B Streptococcus (GBS) is the major cause of neonatal meningitis, but the risk of infection in the colonized neonates is variable. Capsular sialic acid (Sia), whose synthesis is encoded by neu genes, appears to be a major virulence factor in several bacterial species able to reach the cerebrospinal fluid. Therefore, variations of Sia expression related to the genetic diversity of strains may have an impact on the risk of meningitis in colonized neonates. We characterized by MLST the phylogenetic diversity of 64 serotype III GBS strains isolated from vaginal flora and randomly selected. These strains mostly belonged to three major sequence types (STs): ST1 (11 %), ST17 (39 %) and ST19 (31 %). The genetic diversity of strains of these lineages, characterized by PFGE, allowed the selection of 17 representative strains, three ST1, six ST17 and eight ST19, with NEM316 as reference, in order to evaluate (i) by quantitative RT-PCR, the level of transcription of the neuD gene as a marker for the transcription of neu genes and (ii) by enzymological analysis, the expression of Sia. The mean transcription level of neuD was higher for ST17 strains than for ST1 and ST19 strains in the early, mid- and late exponential growth phases, and was maximum in the early exponential growth phase for ST17 strains and in the mid-exponential growth phase for ST1 and ST19 strains. Mean Sia concentration was higher for ST17 than for ST1 and ST9 strains in all three growth phases. For the total population, Sia concentration varied notably in the stationary phase, from 0.38 to 9.30 nmol per 108 viable bacteria, with a median value of 2.99 nmol per 108 bacteria. All ST17 strains, only one-third of the ST19 strains and none of the ST1 strains had Sia concentrations higher than the median Sia concentration. Therefore, differences in the level of expression of Sia by strains of the major serotype III GBS phylogenetic lineages might be one of the factors that explain the leading role of ST17 strains in neonatal meningitis.

scholarly journals Investigation of extramammary sources of Group B Streptococcus reveals its unusual ecology and epidemiology in camels

2021 ◽  
Author(s):  
Dinah Seligsohn ◽  
Chiara Crestani ◽  
Nduhiu Gitahi ◽  
Emelie Lejon Flodin ◽  
Erika Chenais ◽  
...  
Keyword(s):  
Control Strategies ◽  
Bacterial Species ◽  
Group B Streptococcus ◽  
Nasal Carriage ◽  
Sample Collection ◽  
Carriage Rate ◽  
Cross Sectional ◽  
Molecular Features ◽  
Single Locus Variant ◽  
Group B

Camels are vital to food production in the drylands of the Horn of Africa, with milk as their main contribution to food security. A major constraint to camel milk production is mastitis, inflammation of the mammary gland. The condition negatively impacts milk yield and quality as well as household income. The leading cause of mastitis in dairy camels is Streptococcus agalactiae, group B Streptococcus (GBS), which is also a commensal and pathogen of humans. It has been suggested that extramammary reservoirs for this pathogen may contribute to the occurrence of mastitis in camels. We explored the molecular epidemiology of GBS in camels using a cross-sectional study design for sample collection and phenotypic, genomic and phylogenetic analysis of isolates. Among 88 adult camels and 93 calves from six herds in Laikipia County, Kenya, GBS was detected in 20% of 50 milk samples, 25% of 152 nasal swabs, 8% of 90 oral swabs and 3% of 90 rectal swabs, but not in vaginal swabs. Per camel herd, two to four sequence types (ST) were present. More than half of the isolates belonged to ST617 or its single-locus variant, ST1652, with these STs found across all sample types. Serotype VI was detected in 30 of 58 isolates. In three herds, identical STs were detected in milk and swab samples, suggesting that extramammary sources of GBS may contribute to the maintenance and spread of GBS within camel herds. This needs to be considered when developing prevention and control strategies. In addition, the high nasal carriage rate, low recto-vaginal carriage rate, and high prevalence of serotype VI for GBS in camels are in stark contrast to the distribution of GBS in humans and reveal hitherto unknown ecological and molecular features of this bacterial species.

scholarly journals Synthesis of a Klebsiella pneumoniae O-Antigen Heteropolysaccharide (O12) Requires an ABC 2 Transporter

2003 ◽  
Vol 185 (5) ◽  
pp. 1634-1641 ◽  
Author(s):  
Luis Izquierdo ◽  
Susana Merino ◽  
Miguel Regué ◽  
Florencia Rodriguez ◽  
Juan M. Tomás
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genomic Library ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
Complete Analysis ◽  
E Coli ◽  
O Antigen ◽  
High Level ◽  
K 12 ◽  
Reading Frames

ABSTRACT A recombinant clone encoding enzymes for Klebsiella pneumoniae O12-antigen lipopolysaccharide (LPS) was found when we screened for serum resistance of a cosmid-based genomic library of K. pneumoniae KT776 (O12:K80) introduced into Escherichia coli DH5α. A total of eight open reading frames (ORFs) (wb O12 gene cluster) were necessary to produce K. pneumoniae O12-antigen LPS in E. coli K-12. A complete analysis of the K. pneumoniae wb O12 cluster revealed an interesting coincidence with the wb O4 cluster of Serratia marcescens from ORF5 to ORF8 (or WbbL to WbbA). This prompted us to generate mutants of K. pneumoniae strain KT776 (O12) and to study complementation between the two enterobacterial wb clusters using mutants of S. marcescens N28b (O4) obtained previously. Both wb gene clusters are examples of ABC 2 transporter-dependent pathways for O-antigen heteropolysaccharides. The wzm-wzt genes and the wbbA or wbbB genes were not interchangeable between the two gene clusters despite their high level of similarity. However, introduction of three cognate genes (wzm-wzt-wbbA or wzm-wzt-wbbB) into mutants unable to produce O antigen allowed production of the specific O antigen. The K. pneumoniae O12 WbbL protein performs the same function as WbbL from S. marcescens O4 in either the S. marcescens O4 or E. coli K-12 genetic background.

scholarly journals Integrative and Sequence Characteristics of a Novel Genetic Element, ICE6013, in Staphylococcus aureus

2009 ◽  
Vol 191 (19) ◽  
pp. 5964-5975 ◽  
Author(s):  
Davida S. Smyth ◽  
D. Ashley Robinson
Keyword(s):  
Staphylococcus Aureus ◽  
Integration Site ◽  
Open Reading Frames ◽  
Bacterial Conjugation ◽  
Genetic Element ◽  
Direct Repeats ◽  
New Family ◽  
Integrative Conjugative Element ◽  
Sequence Characteristics ◽  
Reading Frames

ABSTRACT A survey of chromosomal variation in the ST239 clonal group of methicillin-resistant Staphylococcus aureus (MRSA) revealed a novel genetic element, ICE6013. The element is 13,354 bp in length, excluding a 6,551-bp Tn552 insertion. ICE6013 is flanked by 3-bp direct repeats and is demarcated by 8-bp imperfect inverted repeats. The element was present in 6 of 15 genome-sequenced S. aureus strains, and it was detected using genetic markers in 19 of 44 diverse MRSA and methicillin-susceptible strains and in all 111 ST239 strains tested. Low integration site specificity was discerned. Multiple chromosomal copies and the presence of extrachromosomal circular forms of ICE6013 were detected in various strains. The circular forms included 3-bp coupling sequences, located between the 8-bp ends of the element, that corresponded to the 3-bp direct repeats flanking the chromosomal forms. ICE6013 is predicted to encode 15 open reading frames, including an IS30-like DDE transposase in place of a Tyr/Ser recombinase and homologs of gram-positive bacterial conjugation components. Further sequence analyses indicated that ICE6013 is more closely related to ICEBs1 from Bacillus subtilis than to the only other potential integrative conjugative element known from S. aureus, Tn5801. Evidence of recombination between ICE6013 elements is also presented. In summary, ICE6013 is the first member of a new family of active, integrative genetic elements that are widely dispersed within S. aureus strains.

scholarly journals Genome Sequence of Serratia marcescens subsp. sakuensis Strain K27, a Marine Bacterium Isolated from Sponge (Haliclona amboinensis)

2018 ◽  
Vol 6 (6) ◽  
pp. e00022-18 ◽  
Author(s):  
Tzi Him Cheng ◽  
Jasnizat Saidin ◽  
Muhd Danish-Daniel ◽  
Han Ming Gan ◽  
Mohd Noor Mat Isa ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Genome Sequence ◽  
Marine Bacterium ◽  
Gene Clusters ◽  
Open Reading Frames ◽  
Nonribosomal Peptides ◽  
Reading Frames

ABSTRACTSerratia marcescens subsp. sakuensis strain K27 was isolated from sponge (Haliclona amboinensis). The genome of this strain consists of 5,325,727 bp, with 5,140 open reading frames (ORFs), 3 rRNAs, and 67 tRNAs. It contains genes for the production of amylases, lipases, and proteases. Gene clusters for the biosynthesis of nonribosomal peptides and thiopeptide were also identified.

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