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Peptostreptococcus is an anaerobic gram-positive coccus that is encountered in dental and sinus infections, pelvic infections in women, osteomyelitis, arthritis, skin and soft-tissues infections, conjunctivitis and bacteraemia [1,2]. We report here, what is to our knowledge, the first cases of spondylitis with discitis caused by Peptostreptococcus.
There are no published methods on plasmid isolation from Peptostreptococcus spp., therefore two methods of plasmid isolation from this genera were analysed: the boiling and alkaline-SDS methods. Plasmid DNA was not recovered by the boiling method, however, with the alkaline-SDS method, cryptic plasmid DNA was detected in two P. asaccharolyticus and one P. magnus strains. To achieve optimum lysis, Peptostreptococcus cells were treated with lysozyme (2 mg/ml) for 15 min. at 37 degrees C followed by proteinase K (0.2 mg/ml) for 1 h at 37 degrees C. In addition we report, the occurrence of clindamycin or metronidazole-resistant peptostreptococci, but these phenotypes were not correlated with plasmid carriage.
BACKGROUND: Peptostreptococcus magnus protein L (PpL) is a multidomain, bacterial surface protein whose presence correlates with virulence. It consists of up to five homologous immunoglobulin binding domains that interact with the variable (VL) regions of kappa light chains found on two thirds of mammalian antibodies. RESULTS: We refined the crystal structure of the complex between a human antibody Fab fragment (2A2) and a single PpL domain (61 residues) to 2.7 A. The asymmetric unit contains two Fab molecules sandwiching a single PpL domain, which contacts similar VL framework regions of two light chains via independent interfaces. The residues contacted on VL are remote from the hypervariable loops. One PpL-Vkappa interface agrees with previous biochemical data, while the second is novel. Site-directed mutagenesis and analytical-centrifugation studies suggest that the two PpL binding sites have markedly different affinities for VL. The PpL residues in both interactions are well conserved among different Peptostreptococcus magnus strains. The Fab contact positions identified in the complex explain the high specificity of PpL for antibodies with kappa rather than lambda chains. CONCLUSIONS: The PpL-Fab complex shows the first interaction of a bacterial virulence factor with a Fab light chain outside the conventional combining site. Structural comparison with two other bacterial proteins interacting with the Fab heavy chain shows that PpL, structurally homologous to streptococcal SpG domains, shares with the latter a similar binding mode. These two bacterial surface proteins interact with their respective immunoglobulin regions through a similar beta zipper interaction.
Sera from patients suffering from Crohn's and other diseases and from healthy subjects were tested for agglutinins to anaerobic, gram-positive coccoid rods belonging to species of Eubacterium and Peptostreptococcus. Four strains labelled Eubacterium contortum (two strains), Eubacterium rectale and Peptostreptococcus productus were agglutinated by a higher percentage of sera from patients with Crohn's disease than from healthy subjects and from patients with liver and intestinal diseases (including ulcerative colitis), ankylosing spondylitis, granulomatous diseases, diseases of immunity and malignancies. The agglutinins were of the IgG and IgM classes and strain-specific; the titres were low. The results obtained with sera from patients with Crohn's disease and healthy people were subjected to discriminant analysis to estimate the probability, based on the combined results with the four strains, that a patient suffers from Crohn's disease. When sera giving an a posteriori probability greater than or equal to 0.95 (a priori probability = 0.5) were considered positive, the test with four strains had a sensitivity of 54% and a specificity of nearly 100%. The results with sera submitted for diagnosis showed that positive reactions in patients with a diagnosis apparently incompatible with Crohn's disease were within acceptable limits.
Brain abscesses can be caused by bacteria, fungi, and parasites. Among bacteria, anaerobic organisms include the Bacteroides species group, Fusobacterium, Peptostreptococcus, and Propionibacterium. In these cases, a 4-week course of parenteral penicillin/cefalosporin and metronidazole is the standard of treatment. We describe a case of brain abscess secondary to anaerobic infection with Peptostreptococcus, which was successfully treated with parenteral and oral linezolid after failure of standard therapy.
We describe a patient with postsurgical anaerobic meningitis due to Peptostreptococcus magnus. In cases of meningitis associated with Peptostreptococcus species reported in the literature, the most common predisposing factors are meningorectal fistulae and head-and-neck surgery. Most patients respond well to appropriate antimicrobial therapy. Surgical intervention may be required in some instances.
In previous studies, gram-positive bacteria which grew rapidly with peptides or an amino acid as the sole energy source were isolated from bovine rumina. Three isolates, strains C, FT (T = type strain), and SR, were considered to be ecologically important since they produced up to 20-fold more ammonia than other ammonia-producing ruminal bacteria. On the basis of phenotypic criteria, the taxonomic position of these new isolates was uncertain. In this study, the 16S rRNA sequences of these isolates and related bacteria were determined to establish the phylogenetic positions of the organisms. The sequences of strains C, FT, and SR and reference strains of Peptostreptococcus anaerobius, Clostridium sticklandii, Clostridium coccoides, Clostridium aminovalericum, Acetomaculum ruminis, Clostridium leptum, Clostridium lituseburense, Clostridium acidiurici, and Clostridium barkeri were determined by using a modified Sanger dideoxy chain termination method. Strain C, a large coccus purported to belong to the genus Peptostreptococcus, was closely related to P. anaerobius, with a level of sequence similarity of 99.6%. Strain SR, a heat-resistant, short, rod-shaped organism, was closely related to C. sticklandii, with a level of sequence similarity of 99.9%. However, strain FT, a heat-resistant, pleomorphic, rod-shaped organism, was only distantly related to some clostridial species and P. anaerobius. On the basis of the sequence data, it was clear that strain FT warranted designation as a separate species. The closest known relative of strain FT was C. coccoides (level of similarity, only 90.6%). Additional strains that are phenotypically similar to strain FT were isolated in this study.(ABSTRACT TRUNCATED AT 250 WORDS)
16S rRNA gene sequences were determined for Eubacterium exiguum and Peptostreptococcus heliotrinreducens. These species were found to be closely related and, together with Eubacterium lentum, to constitute a branch of the Coriobacteriaceae. Two new genera are proposed on the basis of phenotypic characteristics and 16S rRNA gene sequence comparisons: Slackia to include the bile-sensitive species Eubacterium exiguum and P. heliotrinreducens, and Eggerthella to include the bile-resistant Eubacterium lentum. It is proposed that Eubacterium exiguum and Peptostreptococcus heliotrinreducens are transferred to the genus Slackia gen. nov. as Slackia exigua gen. nov., comb. nov. (type strain ATCC 700122T) and Slackia heliotrinireducens gen. nov., comb. nov. (type strain NTCC 11029T), respectively, and Eubacterium lentum is transferred to the genus Eggerthella gen. nov. as Eggerthella lenta gen. nov., comb. nov. with Eggerthella lenta as the type species.
Peptostreptococcus micros is a gram-positive anaerobic coccus which, although considered to be a natural commensal of the human oral cavity, is associated with periodontal, endodontal and peritonsillar infections. Identification of the organism has to date relied upon conventional culture methods and biochemical analyses. The purpose of this study was to develop a PCR method for rapid and specific identification of this organism in clinical samples. A pair of primers was selected, each of which was specific at the 3' end for P. micros DNA; they were used in the PCR assay, resulting in a 1074-bp product. The primers were shown to be specific for P. micros DNA as no PCR products were obtained when genomic DNA extracts from a wide range of other Peptostreptococcus species and other oral bacteria were used as templates. The PCR assay was then applied to the identification of P. micros DNA in subgingival plaque samples from adult periodontitis patients and pus samples from subjects with acute dento-alveolar abscesses. Confirmation of specific amplification of P. micros DNA was obtained by digestion of PCR products with the restriction endonuclease RsaI, which gives a unique restriction profile for P. micros, and DNA sequencing. Sixty-eight subgingival plaque samples from 18 patients were analysed, of which 19 (28%) were positive for P. micros DNA; the proportion of patients carrying P. micros DNA in at least one sampled site was 11 (61%) of 18. Twenty (71%) of 28 pus samples analysed by PCR contained P. micros DNA. These results confirm that P. micros may be involved in the aetiology of acute dentoalveolar abscesses and adult periodontitis. The PCR assay provides a more rapid and reliable alternative to conventional methods for identification of P. micros in clinical samples.
Peptostreptococcus anaerobius is a gram-positive anaerobic coccus that is widely distributed in the normal human flora. The organism has also been implicated as a causative agent of several systemic infections, including endocarditis and infections of the genitourinary and gastrointestinal tracts. Its role in oral disease is less well defined, although it has been implicated in periodontal disease, gingivitis and root canal infections. Identification of P. anaerobius in clinical samples is currently reliant upon traditional culture and biochemical methods. The aim of this study was to develop a novel PCR assay for the detection of P. anaerobius and to attempt detection of this organism in oral samples. PCR primers specific for P. anaerobius DNA were developed by alignment of bacterial 16S ribosomal RNA gene sequences and selection of sequences specific at their 3' ends for P. anaerobius. When used in a PCR assay, positivity for P. anaerobius DNA was indicated by the amplification of a 943-bp product. The primers were shown to be specific for P. anaerobius DNA, as no PCR products were obtained when genomic DNA from a wide range of other Peptostreptococcus species and other oral bacteria were used as templates. The PCR assay was then applied to the detection of P. anaerobius DNA in subgingival plaque samples from adult periodontitis patients and pus aspirates from subjects with acute dento-alveolar abscesses. All of 60 subgingival plaque samples from 16 patients were negative for P. anaerobius DNA. None of the 43 pus samples analysed contained P. anaerobius DNA. These results suggest that P. anaerobius is not a major pathogen in adult periodontitis and dento-alveolar abscesses. The PCR assay is a more rapid, sensitive and specific alternative to culture-based methods for identification of P. anaerobius in clinical samples.
Strains of Peptostreptococcus, Streptococcus and of a Gram-positive coccus, which was initially isolated as an anaerobe but grew subsequently as a facultative organism, were isolated from subcutaneous abscesses in cats. The cat strains of Peptostreptococcus gave metabolic fermentation products in combinations described for P. anaerobius. The Streptococcus strains conformed to the group S. intermedius. The facultative organism described had the metabolic products of P. anaerobius but the distinctly different biochemical characteristics of S. intermedius and fits neither of the genera strictly.
Restriction fragment length polymorphisms (RFLPs) of rRNA genes were evaluated as a tool for intra- and interspecies differentiation of Peptostreptococcus isolates. RFLPs from a collection of 20 clinical isolates and five ATCC strains representing five Peptostreptococcus spp. (P. anaerobius, P. asaccharolyticus, P. magnus, P. micros and P. prevotii) were obtained by hybridization of Southern blots of HindIII- or EcoRI-digested genomic DNA with three probes: probe A, a 0.98 kb HindIII fragment with a partial 16S rRNA gene sequence from P. anaerobius ATCC 27337; probe B, cloned Escherichia coli rrnB operon in plasmid pKK3535; and probe C, E. coli 16S and 23S rRNA. The hybridization patterns varied, but all yielded RFLPs useful for both intra- and inter-species differentiation. RFLPs of P. asaccharolyticus clinical isolates were closely related to each other and differed significantly from those of the ATCC type strains. The profiles of P. prevotii differed from those of the other four species studied, and based on the HindIII- and EcoRI-generated RFLPs, the strains in this species are more heterogeneous than the other four species studied.
Recently, an atypical rough colony morphotype of Peptostreptococcus micros, a species which is found in ulcerating infections, including periodontitis, was isolated. The virulence of morphotypes alone and in combination with Prevotella intermedia and P. nigrescens was investigated both in vivo and in vitro. All strains tested induced abscesses containing fluid pus in a mouse skin model, and lesions caused by monocultures of the rough morphotype strains of P. micros were statistically significantly larger than those induced by the smooth morphotype strains. Inocula containing both morphotypes produced similar sized abscesses compared to mono-inocula containing the same bacterial load. Both Prevotella species induced small abscesses when inoculated alone, and when Pr. nigrescens was inoculated with one of the other strains, the abscesses were not significantly different from the abscesses induced by the mono-infections of this strain. Synergy, in terms of higher numbers of colony forming units (cfu) in the mixed inocula, was found for all combinations of the rough morphotypes of P. micros and both Prevotella spp. Pus from abscesses caused by combinations of Peptostreptococcus and Prevotella spp. transmitted the infection to other mice, but no abscesses were formed in mice inoculated with pus induced by mono-inocula. These results demonstrated synergic activity between both rough and smooth P. micros strains and oral Prevotella strains. The in-vitro co-culture experiments produced no evidence of growth stimulation. The effect of P. micros strains on the immune system was investigated by testing their ability to initiate luminol-dependent chemiluminescence of polymorphonuclear leucocytes in the presence and absence of human serum. In the latter, the rough morphotype strains initiated higher counts than the smooth morphotype strains. Further work is needed to elucidate the difference in virulence between the smooth and the rough morphotype cells of P. micros and the nature of the interaction with the Prevotella spp.
The surface ultrastructure of three anaerobic Gram-positive cocci frequently encountered in oral infections, Peptostreptococcus micros, P. magnus and P. anaerobius, was studied. The type strains of P. micros (DSM 20468) and P. anaerobius (ATCC 27337), several clinical isolates of both species and the type strain of P. magnus (DSM 20470) were included. Thin-sectioned cells studied by electron microscopy revealed a homogeneous layer outside the peptidoglycan layer in P. anaerobius. In P. micros and P. magnus a more amorphous layer was present. No periodic structures were seen in negatively stained whole cells of these three species. However, in freeze-etched cells of P. anaerobius a crystalline surface protein layer (S-layer) was detected. No periodicity was seen in any of the P. micros strains or the P. magnus type strain by the methods used, but a periodic pattern was observed in negatively stained specimens of cell wall fragments of sonicated P. anaerobius cells. No capsular material was visible outside the S-layer in P. anaerobius. The cells of the Peptostreptococcus spp. were extracted for 30 min with detergents and urea. One per cent SDS and M urea both extracted a major 78 kDa protein from all strains of P anaerobius. Extraction of P. micros and P. magnus cells did not reveal any major protein bands comparable to that of P. anaerobius. Surface biotinylation of cells followed by Western blotting and detection by alkaline-phosphatase-conjugated extravidin showed strong staining of the 78 kDa band in P. anaerobius, further indicating that this molecule is located on the surface of the cell and is the S-protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven strains of anaerobic Gram-positive cocci isolated from human oral sites were subjected to a comprehensive range of phenotypic and genotypic tests. 16S rRNA gene sequence analysis revealed that the strains constituted a homogeneous group that was distinct from species with validly published names, but related to Peptostreptococcus anaerobius. All oral strains tested belonged to this group, whereas all non-oral strains studied were confirmed as P. anaerobius. A novel species, Peptostreptococcus stomatis sp. nov., is proposed to accommodate these oral strains. P. stomatis is weakly saccharolytic and produces acetic, butyric, isobutyric, isovaleric and isocaproic acids as end products of fermentation. The type strain of P. stomatis is W2278T (=DSM 17678T = CCUG 51858T); the G+C content of the DNA of this strain is 36 mol%.
There are high amounts of hydrogen sulfide in deep periodontal pockets. This volatile sulfur compound may be formed from L-cysteine, but only low levels of this amino acid can be expected to be present in periodontal pockets. Glutathione, L-gamma-glutamyl-L-cysteinylglycine, is in high concentration in most tissue cells, and this tripeptide may be more readily available as a source of hydrogen sulfide formation in the pockets. The ability of 37 different species of oral bacteria to utilize glutathione in hydrogen sulfide formation was studied. Of these species, only 2 species of Peptostreptococcus and 5 species of Fusobacterium formed high amounts of hydrogen sulfide from glutathione within 24 h. Since the initial rate of hydrogen sulfide formation was more than 5 times higher in Peptostreptococcus micros than in any of the other bacterial species, the kinetics of sulfide formation from glutathione by P. micros was further elucidated. The formation of sulfide followed quite closely hyperbolic Michaelis-Menten kinetics. The maximal initial rate of sulfide formation (Vmax) was 163 +/- 2 nmol sulfide per minute per milligram of cellular protein. Half maximal initial rate (Km) was obtained at 7.4 +/- 0.8 microM glutathione. The initial rate of sulfide formation from L-cysteine was much slower and was almost proportional to L-cysteine concentration. This difference in kinetics of sulfide formation between glutathione and L-cysteine strongly suggested that glutathione was actively transported into the cell, whereas the transport of L-cysteine was more or less controlled by diffusion. The sulfide formation from the dipeptide L-cysteinylglycine also followed quite closely hyperbolic Michaelis-Menten kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)
A comparative analysis of 16S ribosomal RNA sequences of all Peptostreptococcus species revealed that most members of the genus Peptostreptococcus should be divided into many different genera. The relationship between clostridia and peptostreptococci was analysed to find the phylogenetic position of peptostreptococci.
A physical and genetic map of Finegoldia magna (formerly Peptostreptococcus magnus) ATCC 29328 chromosome was constructed. The order of rare cleavage restriction fragments was determined by double digestion with the restriction enzymes I-CeuI, SgrAI, ApaI and PmeI, cross-hybridization and ApaI-linking clones. The size of the circular chromosome of F. magna was estimated to be 1.9 Mb. This strain also had a 200-kb megaplasmid. The chromosome contained four rrn operons, and the orientation of two rrn operons was opposite to the others. Fragment analysis of Peptostreptococcus anaerobius ATCC 27337(T) chromosome suggested that its size was much smaller than that of F. magna ATCC 29328.