Streptococcus Ferus Research Articles

The ComRS-SigX Pathway Regulates Natural Transformation in Streptococcus ferus.

The ability to take up and incorporate foreign DNA via natural transformation is a well-known characteristic of some species of Streptococcus, and is a mechanism that rapidly allows for the acquisition of antibacterial resistance. Here, we describe that the understudied species Streptococcus ferus is also capable of natural transformation and uses a system analogous to that identified in Streptococcus mutans. S. mutans natural transformation is under the control of the alternative sigma factor sigX (also known as comX), whose expression is induced by two types of peptide signals: CSP (competence stimulating peptide, encoded by comC) and XIP (sigX-inducing peptide, encoded by comS). These systems induce competence via either the two-component signal-transduction system ComDE or the RRNPP transcriptional regulator ComR, respectively. Protein and nucleotide homology searches identified putative orthologs of comRS and sigX in S. ferus, but not homologs of S. mutans blpRH (also known as comDE). We demonstrate that natural transformation in S. ferus is induced by a small, double-tryptophan containing sigX-inducing peptide (XIP), akin to that of S. mutans, and requires the presence of the comR and sigX orthologs for efficient transformation. Additionally, we find that natural transformation is induced in S. ferus by both the native XIP and the XIP variant of S. mutans, implying that cross talk between the two species is possible. This process has been harnessed to construct gene deletions in S. ferus and provides a method to genetically manipulate this understudied species. IMPORTANCE Natural transformation is the process by which bacteria take up DNA and allows for acquisition of new genetic traits, including those involved in antibiotic resistance. This study demonstrates that the understudied species Streptococcus ferus is capable of natural transformation using a peptide-pheromone system like that previously identified in Streptococcus mutans and provides a framework for future studies concerning this organism.

The viridans group streptococci

The viridans group streptococci (VGS) are an extremely diverse range of organisms within the genus Streptococcus, which are characterized by a greening of the blood in blood agar, on which they are normally grown. Oral streptococci largely comprise members of the VGS, which currently include 20 species, which are commensal inhabitants of the oropharyngeal cavity, and the gastrointestinal and genital tracts of mammals. On the basis of 16S rRNA sequence homology, these bacteria are categorised into four groups: the salivarius rRNA homology group, including Streptococcus thermophilus, Streptococcus vestibularis and Streptococcus salivarius; the mitis group, including Streptococcus cristatus, Streptococcus gordonii, Streptococcus oralis, Streptococcus mitis, Streptococcus pneumoniae, Streptococcus sanguinis and Streptococcus parasanguinis; the anginosus group, including Streptococcus anginosus, Streptococcus constellatus and Streptococcus intermedius; and the mutans group, including Streptococcus mutans, Streptococcus criceti, Streptococcus downei, Streptococcus ferus, Streptococcus macacae, Streptococcus ratti and Streptococcus sobrinus. This review aims at comparing conventional and molecular detection methods and the emergence of antibiotic resistance within the VGS.

Bioactive Steroidal Alkaloids fromSarcococca hookeriana

Four new 5 alpha-pregnane-type steroidal alkaloids, hookerianamides L(1), M(2), N(3), and O(4), and a known N-formylchonemorphine (5) have been isolated by acid-base extraction of the dichloromethane extract of Sarcococca hookeriana. The structures of all compounds were determined with spectroscopic techniques and by comparison with literature data. All compounds displayed antileishmanial and antibacterial properties. Compounds 1, 4, and 5 were found to be more potent than standard pentamidine (IC (50) = 9.59 microg/mL) with respect to leishmanicidal activity. The minimum inhibitory concentration of most of the compounds against Bacillus subtilis, Streptococcus minor, and Streptococcus ferus was lower than that of the standard ampicillin.

Antibacterial constituents from Leucosceptrum canum

Four new long-chain compounds, leucoperoxyterpene ( 1), leucoester ( 2), leucoic acid ( 3), and leucoenoic acid ( 4) has been isolated from aerial parts of the medicinal plant Leucosceptrum canum together with fifteen known compounds. Compound 1 was found to be a member of the rare class of peroxy open chain natural products. The structures of all compounds were assigned by means of modern spectroscopic techniques. All compounds were tested for their antibacterial activities against Bacillus subtilis, Escherichia coli, Micrococcus luteus, Pseudomonas agarici, Streptococcus minor, and Streptococcus ferus, in which, compounds 1, and 10– 15 exhibited potent to moderate activities.

Antibacterial Ellagic Acid Derivatives and Other Constituents from Pancovia pedicellaris

Two new ellagic acid derivatives, named panconosides A (1) andB(2) were isolated from Pancovia pedicellaris together with eleven known compounds (3 - 13). The structures of 1 and 2, as well as those of the known compounds were established by spectroscopic methods and by comparison with previously reported data. Compounds 1 and 2 were tested in vitro for their antibacterial potential against six strains of microorganisms: Micrococcus luteus, Streptococcus ferus, Streptococcus minor, Escherichia coli, Bacillus subtilis, and Pseudomonas agarici. They were found to exhibit moderate antibacterial activity against all the tested strains compared to standard drugs.

Cariogenicity of Three Kinds of Mutans Streptococci from Pig Oral Cavity

Three kinds of mutans streptococci ; Streptococcus ferus and two Streptococcus orisuis serovar strains, in the pig oral cavity were identified previously. The ability to form plaque and synthesise insoluble glucan from sucrose was relatively limited in S. ferus and S. orisuis compared with Streptococcus mutans. PCR analysis showed that the two S. orisuis serovar strains possessed a glucosyltransferase (GTase) I gene. S. ferus could not be amplified with GTase B and GTase I primers. Acid production of all test strains was similar and depended on the cell number. In rat caries experiments, S. ferus and the two S. orisuis serovar strains achieved a lower caries score than S. mutans. The total number of bacteria in the rat oral cavity was also lower for these strains than for S. mutans. The S. ferus and two S. orisuis serovar strains from pigs had relatively weak cariogenic potential compared to S. mutans.

Identification of Streptococcus ferus and the Distribution of Three Kinds of Mutants Streptococci from Pig Tooth Surface

Mutans streptococci has been implicated as a primary causative agent of dental caries in animal. Two kinds of mutans streptococci, Streptococcus orisuis serovar strains were identified previously. New gram-positive streptococcal mutans-like strains from the oral flora of pigs were characterized. The distribution of three kinds of the mutans streptococci was studied. A third strain was newly identified as Streptococcus ferus based on 16S rRNA gene sequencing, G+C content, DNA-DNA homology, and extensive biochemical testing, and serologically grouped into serotype c of mutans streptococci. The distribution of three strains revealed that S. ferus was the predominant species. S. orisuis serovar strains made up 4∼13% of all the streptococci in young pigs. These results suggest that the detection rate of these mutans streptococci corelates with feed containing sucrose and S. ferus is the outlived strain among the three mutans streptococci in pig oral cavity.

Streptococcus massiliensis sp. nov., isolated from a patient blood culture

An unidentified strain of the viridans group of streptococci was isolated from a human blood sample. It was distinguished from all other recognized species of the Streptococcus sanguinis group by several biochemical characteristics. Phylogenetic analysis based on 16S rRNA gene sequence comparisons clustered this strain with Streptococcus ferus (mutans group) but phylogenetic analysis based on rpoB and sodA gene sequence comparisons included it in the S. sanguinis group. The isolate showed 95.4 and 95.2 % 16S rRNA gene sequence similarity to S. ferus and S. sanguinis, respectively, confirming it as belonging to a novel taxon, for which the name Streptococcus massiliensis sp. nov. is proposed. The type strain is 4401825T (=CIP 108498T=CCUG 49690T).

Comparison of culture media and chairside assays for enumerating mutans streptococci

This study compared several traditional culture-based media and chairside cultural assays for ability to recover mutans streptococci (MS) from pure cultures and from saliva samples. When pure cultures were used with traditional culture-based media, mitis-salivarius bacitracin (MSB) agar demonstrated less support for bacterial recovery than trypticase-yeast extract-cysteine sucrose-bacitracin (TYCSB) agar and the modified medium of Ritz (HLR-S). One species of MS, Streptococcus ferus (c), was not recovered on MSB medium. Chairside cultural tests displayed considerable disparity between tests in recovering bacteria from pure cultures. On the glass adherence assay (Mucount), S. ferus was not detected and Streptococcus criceti was not detected on the dipslide assay (Cariescreen SM) or on the plastic adherence assay (Dentocult SM Strip mutans). The frequency of isolation of pure strains of bacteria other than MS was common. From saliva samples, the frequency of isolation of MS on HLR-S and TYCSB media and the glass adherence assay was 91-97%. The frequency of isolation on MSB medium and on the dip-slide and plastic adherence assays was significantly decreased (37, 47 and 69%, respectively). Recovery scores varied considerably among the culture methods studied and tended to be highest on the HLR-S medium and on the glass adherence assay. Growth and recovery profiles of pure bacterial cultures and of saliva samples for the MS varied according to different media. Caution should be exercised in comparing results between studies that employ different cultural methods for MS enumeration.

Streptococcus devriesei sp. nov., from Equine Teeth

Phenotypic and phylogenetic studies were performed on four unidentified Gram-positive staining, catalase-negative, alpha-hemolytic Streptococcus-like organisms recovered from the teeth of horses. SDS PAGE analysis of whole-cell proteins and comparative 16S rRNA gene sequencing demonstrated the four strains were highly related to each other but that they did not correspond to any recognised species of the genus Streptococcus. Phylogenetic analysis based on 16S rRNA gene sequences showed the unidentified organisms form a hitherto unknown sub-line within the Streptococcus genus, displaying a close affinity with Streptococcus mutans, Streptococcus ferus and related organisms. Sequence divergence values of > 5% with these and other reference streptococcal species however demonstrated the organisms from equine sources represent a novel species. Based on the phenotypic distinctiveness of the new bacterium and molecular chemical and molecular genetic evidence, it is proposed that the unknown species be classified as Streptococcus devriesei sp. nov. The type strain of Streptococcus devriesei is CCUG 47155T (= CIP 107809T).

Identification of mutans streptococci by restriction fragment length polymorphism analysis of polymerase chain reaction-amplified 16S ribosomal RNA genes.

Mutans streptococci are frequently isolated from dental plaque and carious lesions. These bacteria have been identified by conventional methods such as biochemical and serologic tests followed by the isolation of colonies on the mitis-salivarius agar, which are sometimes inconsistent. Recently, species-specific polymerase chain reaction (PCR) has been reported to rapidly identify Streptococcus mutans and Streptococcus sobrinus. However, in the case of identification and classification into several species, e.g. within the group of mutans streptococci consisting of seven species, the identification using species-specific PCR seems somewhat inefficient because of need for the development and preparation of specific primers for each species. Therefore, in this study we developed a simple method using restriction fragment length polymorphism analysis of PCR-amplified 16S ribosomal RNA genes (16S rRNA genes PCR-RFLP) for the identification of seven different species included in the group of mutans streptococci. We amplified 16S rRNA gene sequences from genomic DNA samples by PCR using universal primers and digested the PCR products with the restriction endonucleases, HpaII and HaeIII. HpaII produced six RFLP patterns for eight reference strains, since the patterns for S. sobrinus, Streptococcus downei and Streptococcus ferus were similar. RFLP patterns produced with HaeIII could separate these three species. Furthermore, the RFLP patterns predicted from the 16S rRNA gene sequences in the GenBank database agreed with the actual RFLP patterns produced in the present study. The 16S rRNA sequence comparisons can be used to identify oral mutans streptococci; however, the identification by sequencing is sometimes difficult in large-scale studies and for small laboratories. Therefore, 16S rRNA genes PCR-RFLP, using HpaII and HaeIII, could be an alternative method for the identification of mutans streptococci, and may be applicable for large-scale studies on the cariogenicity of mutans streptococci.

Emended description of Streptococcus ferus isolated from pigs and rats.

Streptococcus ferus is a mutans-like streptococcus originally isolated from wild rats fed with sugar cane. Taxonomically, this species has not been studied extensively. Ten Gram-positive coccal strains, isolated from the tonsils and nasal conchae of piglets, were identified as S. ferus by 16S rDNA sequencing, tRNA-intergenic spacer length polymorphism analysis (tDNA-PCR), whole-cell protein profiling using SDS-PAGE, G+C content determination and extensive biochemical testing. In all these tests, the type strain of S. ferus (LMG 16520T), from a rat, was included. The results of the tests are described and an emended species description is presented.

Mobilisation of the streptococcal plasmid pMV158: interactions of MobM protein with its cognate oriT DNA region.

The streptococcal plasmid pMV158 encodes the relaxase protein, MobM, involved in its mobilisation. Purified MobM protein specifically cleaved supercoiled or single-stranded DNA containing the plasmid origin of transfer, oriT. Gel retardation and DNase I footprinting assays performed with DNA fragments containing the plasmid oriT provided evidence for specific binding of MobM by oriT DNA. Dissection of the MobM-binding sequence revealed that the oriT region protected by MobM spanned 28 nucleotides, and includes an inversely repeated sequence, termed IR2. MobM exhibits a high degree of similarity with the mob gene product of the Streptococcus ferus plasmid pVA380-1. Although the origins of transfer of pMV158 and pVA380-1 show 20% sequence divergence in a 24-bp sequence included in their oriT regions, the pMV158 MobM was able to cleave a supercoiled derivative of pVA380-1 in vitro.

Streptococcus downei sp. nov. for Strains Previously Described as Streptococcus mutans Serotype h

Strains of streptococci originally isolated from the dental plaque of monkeys (Macaca fascicularis) and designated as Streptococcus mutans serotype h were compared with the other species of the mutans streptococcus group. Despite the close resemblance noted previously between these strains and Streptococcus sobrinus, closer examination revealed several important differences. Strains of serotype h ferment mannitol but not sorbitol, melibiose, inulin, or raffinose, do not produce hydrogen peroxide, and are unable to grow in the presence of bacitracin at 2 units per ml. They exhibit a distinct polypeptide pattern by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and possess several antigens absent from S. sobrinus as revealed by Western blotting (immunoblotting). Virtually identical polar lipid patterns were observed by two-dimensional thin-layer chromatography for both serotype h strains and S. sobrinus, although on the basis of long-chain fatty acid analysis by capillary gas-liquid chromatography, the former could be distinguished by the presence of a peak tentatively identified as cyclopropane acid (cis-9, 10-methyleneoctadecanoate (ΔC 19:0). Deoxyribonucleic acid (DNA)-DNA hybridization studies by both the S1 nuclease and renaturation rate methods showed that serotype h strains differ from S. mutans, S. sobrinus, Streptococcus cricetus, Streptococcus rattus, Streptococcus ferus, and Streptococcus macacae. On the basis of these data, we believe that S. mutans serotype h strains represent a distinct species for which the name Streptococcus downei is proposed. The DNA base composition is 41 to 42 moles percent guanine plus cytosine. The type strain is strain MFe28 (NCTC 11391T), which is cariogenic in monoassociated germfree rats.

Penicillin-induced lysis in related species of oral streptococci.

Treatment of 10 strains representing 5 species of related oral streptococci with penicillin G resulted in measurable levels of cellular lysis. This lysis was dependent on penicillin concentration and cell density. At similar penicillin concentrations and cell densities, the 10 strains demonstrated appreciable differences in their lytic responses. Lysis values for Streptococcus mutans (GS‐5 and Ingbritt) and Streptococcus rattus (BHT and FA‐1) were greater than those for Streptococcus sobrinus (01 and B13), Streptococcus cricetus (HS6 and AHT), and Streptococcus ferus(8S1 and HD3).

Penicillin-induced lysis of Streptococcus mutans.

Treatment of Streptococcus mutans GS-5 cells with concentrations of penicillin G within a relatively narrow range resulted in substantial lysis. This penicillin-induced lysis was dependent upon cell density and pH of the lysis medium. Other oral streptococci (Streptococcus sobrinus, Streptococcus rattus, and Streptococcus cricetus) also demonstrated substantial levels of penicillin-induced lysis under appropriate conditions. Lesser degrees of lysis were seen in a related organism, Streptococcus ferus.

Streptococcus macacae sp. nov. from Dental Plaque of Monkeys (Macaca fascicularis)

We propose the name Streptococcus macacae sp. nov. for gram-positive, catalase-negative streptococcal strains that were isolated from the dental plaque of monkeys (Macaca fascicularis). This organism is distinct from other oral streptococci in that it produces acid from mannitol and raffinose but not from inulin or dextrin. It is not able to grow in the presence of bacitracin and does not produce hydrogen peroxide or hydrolyze arginine, but esculin is hydrolyzed, and dextran is produced from sucrose. Streptococcus macacae sp. nov. possesses the serotype c antigen described by Bratthall, as do Streptococcus mutans and Streptococcus ferus; however, the protein profiles of whole-cell extracts subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and differences in deoxyribonucleic acid composition demonstrate that the new isolates are distinct from the two other species that possess the serotype c antigen and from other mutans streptococci. The guanine-plus-cytosine content of S. macacae is 35 to 36 mol%. The type strain is strain 25-1 (- NCTC 11558).

Streptococcus sobrinus nom. rev. and Streptococcus ferus nom. rev.: Habitat of These and Other Mutans Streptococci

Streptococcus sobrinus and Streptococcus ferus were not included on the Approved List of Bacterial Names in 1980. Type strains of these species are now available, and I propose that they be recognized. The available evidence indicates that S. ferus is a commensal of wild rats and that S. sobrinus and the other mutans streptococci (except S. ferus) are human commensals.

Physiology of "mutans-like" Streptococcus ferus from wild rats.

Strains of Streptococcus ferus isolated from the oral cavities of wild rodents inhabiting sucrose-rich and sucrose-poor environments have many traits in common with the "mutans" streptococci. Thus, S. ferus HD3 and 8S1, like cariogenic S. sobrinus 6715-13, from adherent, alpha (1 leads to 3) glucopyranosyl-glucose linkage-rich, plaquelike deposits in vitro and in vivo through the action of constitutive glucosyltransferase(s) enzymes on sucrose, produce and degrade intracellular polysaccharide, produce short-chain fatty acids from the catabolism of mono- and disaccharides, carry the c antigen of S. mutans, and penetrate, persist, and proliferate in a sucrose-augmented fashion in the oral cavities of specific-pathogen-free rodent caries models. However, unlike infection with common S. mutans, infection with tested S. ferus strains does not cause caries. This avirulence appeared to result more from the reduced aciduricity of S. ferus than from differences in glucosyltransferase complements. Studies showed that despite generally similar growth rates and extracellular glucan syntheses, the acidogenic metabolism of S. ferus was more inhibited by declining environmental pH than was cariogenic S. sobrinus 6715-13 and that, in vitro, less hydroxyapatite was solubilized by S. ferus metabolic end products. The physiology of these S. ferus strains demonstrated that, in addition to plaque formation and acid production, acid tolerance was crucial to the carious process.

Colonization and cariogenicity of Streptococcus ferus in rats.

Streptococcus ferus, which is indigenous to wild rats, is a member of the mutans group of streptococci. We tested its ability to colonize and to cause caries in laboratory rats by comparing two strains of S. ferus with the very cariogenic Streptococcus sobrinus strain 6715. Groups of rats were fed either finely ground mouse chow or a 56% sucrose diet, or they were switched from chow to the sucrose diet. All three strains colonized the mouths of rats regardless of diet. However, the infectants reached higher proportions of the total flora more quickly in the rats consuming sucrose. Similarly, the percentage of the oral flora represented by an infecting organism increased numerically when rats originally fed chow were switched to the sucrose diet. S. ferus formed plaques on the teeth of the rats, but these plaques did not proliferate over smooth tooth surfaces as extensively as did those of S. sobrinus. Although S. ferus colonized and accumulated, it was non-cariogenic in rats fed sucrose compared both with rats fed similarly but infected with S. sobrinus 6715 and with uninfected controls. In vitro measurements suggested the S. ferus produced acid less rapidly than S. sobrinus. Thus, the lack of cariogenicity in S. ferus may result from an inability to form copious plaques on smooth tooth surfaces and from low acid production and, therefore, may represent a natural absence of the pathogenic potential usually inherent in the mutans streptococci.