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PubMed2003

The effects of hyaluronan and its fragments on lipid models exposed to UV irradiation.

The effects of hyaluronan and its degradation products on irradiation-induced lipid peroxidation were investigated. Liposomal skin lipid models with increasing complexity were used. Hyaluronan and its fragments were able to reduce the amount of lipid peroxidation secondary products quantified by the thiobarbituric acid (TBA) assay. The qualitative changes were studied by mass spectrometry. To elucidate the nature of free radical involvement electron paramagnetic resonance (EPR) studies were carried out. The influence of hyaluronan and its fragments on the concentration of hydroxyl radicals generated by the Fenton system was examined using the spin trapping technique. Moreover, the mucopolysaccharide's ability to react with stable radicals was checked. The quantification assay of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) showed no concentration changes of the stable radical caused by hyaluronan. Hyaluronan was found to exhibit prooxidative effects in the Fenton assay in a concentration dependent manner. A transition metal chelation was proposed as a mechanism of this behavior. Considering human skin and its constant exposure to UV light and oxygen and an increased pool of iron in irradiated skin the administration of hyaluronan or its fragments in cosmetic formulations or sunscreens could be helpful for the protection of the human skin.

Electron Spin Resonance Spectroscopy↗
PubMed2004

Characterization of the purified hyaluronan synthase from Streptococcus equisimilis.

Hyaluronan synthase (HAS) utilizes UDP-GlcUA and UDP-GlcNAc in the presence of Mg(2+) to form the GAG hyaluronan (HA). The purified HAS from Streptococcus equisimilis (seHAS) shows high fidelity in that it only polymerizes the native substrates, UDP-GlcNAc and UDP-GlcUA. However, other uridinyl nucleotides and UDP-sugars inhibited enzyme activity, including UDP-GalNAc, UDP-Glc, UDP-Gal, UDP-GalUA, UMP, UDP, and UTP. Purified seHAS was approximately 40% more active in 25 mM, compared to 50 mM, PO(4) in the presence of either 50 mM NaCl or KCl, and displayed a slight preference for KCl over NaCl. The pH profile was surprisingly broad, with an effective range of pH 6.5-11.5 and the optimum between pH 9 and 10. SeHAS displayed two apparent pK(a) values at pH 6.6 and 11.8. As the pH was increased from approximately 6.5, both K(m) and V(max) increased until pH approximately 10.5, above which the kinetic constants gradually declined. Nonetheless, the overall catalytic constant (120/s) was essentially unchanged from pH 6.5 to 10.5. The enzyme is temperature labile, but more stable in the presence of substrate and cardiolipin. Purified seHAS requires exogenous cardiolipin for activity and is very sensitive to the fatty acyl composition of the phospholipid. The enzyme was inactive or highly activated by synthetic cardiolipins containing, respectively, C14:0 or C18:1(Delta9) fatty acids. The apparent E(act) for HA synthesis is 40 kJ (9.5 kcal/mol) disaccharide. Increasing the viscosity by increasing concentrations of PEG, ethylene glycol, glycerol, or sucrose inhibited seHAS activity. For PEGs, the extent of inhibition was proportional to their molecular mass. PEGs with average masses of 2.7, 11.7, and 20 kg/mol caused 50% inhibition of V(max) at 21, 6.5, and 3.5 mM, respectively. The apparent K(i) values for ethylene glycol, glycerol, and sucrose were, respectively, 4.5, 3.3, and 1.2 mM.

Cardiolipins↗
PubMedDate not supplied

Evaluation of hyaluronan from different sources: Streptococcus zooepidemicus, rooster comb, bovine vitreous, and human umbilical cord.

Sodium hyaluronate (HA) is widely distributed in extracellular matrixes and can play a role in orchestrating cell function. Consequently, many investigators have looked at the effect of exogenous HA on cell behavior in vitro. HA can be isolated from several sources (e.g., bacterial, rooster comb, umbilical cord) and therefore can possess diverse impurities. This current study compares the measured impurities and the differences in biological activity between HA preparations from these sources. It was demonstrated that nucleic acid and protein content was highest in human umbilical cord and bovine vitreous HA and was low in bacterial and rooster comb HA. Macrophages exposed to human umbilical cord HA produced significantly higher amounts of TNF-alpha relative to control or bacterial-derived HA. These results indicate that the source of HA should be considered due to differences in the amounts and types of contaminants that could lead to widely different behaviors in vitro and in vivo.

Animals↗
PubMed2001

Follow-up of patients with epidemic poststreptococcal glomerulonephritis.

In 1998 there was a large outbreak of acute glomerulonephritis (GN) in Nova Serrana, Brazil, caused by group C Streptococcus zooepidemicus and linked to the consumption of contaminated cheese produced with unpasteurized milk. This study describes the follow-up of these patients after a mean of 2 years following the acute episode. Of 134 patients identified in 1998, 69 patients were reexamined and underwent measurements of blood pressure, 24-hour creatinine clearance, microalbuminuria (radioimmunoassay), and urine sediment analysis. Of the original group of 134 patients, 3 patients died in the acute phase and 5 patients (3.7%) required chronic dialysis. Of 69 patients reevaluated, 65 patients (94%) were adults (mean age, 39 +/- 2 [SE] years) and 47 patients (68%) were women. At the follow-up examination, we found arterial hypertension in 42% of subjects (27 of 64 subjects), serum creatinine levels greater than 1.2 mg/dL in 12% (10 of 68 subjects), reduced creatinine clearance (<80 mL/min/1.73 m(2)) in 30% (20 of 67 subjects, 2 of them on chronic dialysis therapy), and increased microalbuminuria (>20 microg/min) in 34% (22 of 65 subjects). Increased microalbuminuria and/or reduced creatinine clearance were detected in 48% of the subjects (31 of 65 subjects). Patients with microalbuminuria had greater diastolic blood pressure than those without microalbuminuria (mean, 98 +/- 4 versus 88 +/- 2 mm Hg; P = 0.02). In conclusion, after a mean of 2 years, patients with epidemic poststreptococcal GN caused by S zooepidemicus present a high rate of hypertension and frequent abnormalities of renal function, with some having reached end-stage renal disease. Longer follow-up will be important to define the prognosis of these patients.

Adolescent↗
PubMed2001

Acute bacterial arthritis caused by group C streptococci.

OBJECTIVES: To summarize the characteristics of and clinical experience with joint infection by group C streptococcus. METHODS: Two new cases of acute bacterial arthritis due to group C streptococci are reported, and a MEDLINE search was performed, which located 22 additional cases. RESULTS: Mean age (+/- standard deviation) of all 24 patients was 46 +/- 25 years, and most patients were men (75%). The species most frequently identified was Streptococcus equisimilis (12 cases). Eight patients (33%) had a general risk factor for infection, and the same percentage had some type of arthropathy. Only 3 patients had previous contact with animals. The infection was polyarticular in a third of cases, and the joint most frequently involved was the knee. The majority of patients showed a good response to the treatment with intravenous penicillin. However, 3 patients had functional sequelae, 2 more had residual radiological lesions, and 3 died. CONCLUSIONS: Acute bacterial arthritis due to group C streptococci is a serious but uncommon entity that can affect patients without risk factors. Rapid diagnosis and treatment may improve the outcome. Semin Arthritis Rheum 31:43-51.

Adolescent↗
PubMed2006

Mutation of two intramembrane polar residues conserved within the hyaluronan synthase family alters hyaluronan product size.

We identified two conserved polar amino acids within different membrane domains (MD) of Streptococcus equisimilis hyaluronan synthase (seHAS), Lys48 in MD2 and Glu327 in MD4. In eukaryotic HASs, the position of the Glu is very similar and the Lys is replaced by a conserved polar Gln. To assess whether Lys48 and Glu327 interact or influence seHAS activity, we investigated the effects of changing Lys48 to Arg or Glu and Glu327 to Lys, Asp, or Gln. Mutants, including a double switch variant with Lys48 and Glu327 exchanged, were expressed and assayed in Escherichia coli membranes. SeHASE327Q and seHASE327K were expressed at low levels, whereas seHASE327D and the Lys48 mutants were expressed well. The specific enzyme activities (relative to wild type) were 17 and 7% for the K48R and K48E mutants and 26 and 38% for the E327Q and E327D mutants, respectively. In contrast, seHAS(E327K) showed only 0.16% of wild-type activity but was rescued over 46-fold by changing Lys48 to Glu. Expression of the seHASE327K,K48E protein was also rescued to near wild-type levels. Based on size exclusion chromatography coupled to multiangle laser light scattering analysis, all the variants synthesized hyaluronan (HA) of smaller weight-average molar mass than wild-type enzyme (3.6 MDa); the smallest HA (approximately 0.6 MDa) was made by seHASE327K,K48E and seHASK48E. The results indicate that Glu327 within MD4 is a critical residue for the stability of seHAS, that it may interact with Lys48 within MD2, and that these residues are involved in the ability of HAS to synthesize very large HA.

Amino Acid Sequence↗
PubMed2003

Streptococcus zooepidemicus meningitis and bacteraemia.

Group C streptococci are common causative agents of epidemic infections in animals and a rare cause of meningitis in humans. The case is reported of a 75-y-old man with meningitis caused by a group C streptococcus (Streptococcus zooepidemicus). He had frequent contact with horses, which were a possible source of infection. In spite of treatment with a third generation cephalosporin, the outcome was fatal.

Aged↗
PubMed2004

Identification of a membrane-localized cysteine cluster near the substrate-binding sites of the Streptococcus equisimilis hyaluronan synthase.

The membrane-bound hyaluronan synthase (HAS) from Streptococcus equisimilis (seHAS), which is the smallest Class I HAS, has four cysteine residues (positions 226, 262, 281, and 367) that are generally conserved within this family. Although Cys-null seHAS is still active, chemical modification of cysteine residues causes inhibition of wild-type enzyme. Here we studied the effects of N-ethylmaleimide (NEM) treatment on a panel of seHAS Cys-mutants to examine the structural and functional roles of the four cysteine residues in the activity of the enzyme. We found that Cys226, Cys262, and Cys281 are reactive with NEM, but Cys367 is not. Substrate protection studies of wild-type seHAS and a variety of Cys-mutants revealed that binding of UDP-GlcUA, UDP-GlcNAc, or UDP can protect Cys226 and Cys262 from NEM inhibition. Inhibition of the six double Cys-mutants of seHAS by sodium arsenite, which can cross-link vicinyl sulfhydryl groups, also supported the conclusion that Cys262 and Cys281 are close enough to be cross-linked. Similar results indicated that Cys281 and Cys367 are also very close in the active enzyme. We conclude that three of the four Cys residues in seHAS (Cys262, Cys281, and Cys367) are clustered very close together, that these Cys residues and Cys226 are located at the inner surface of the cell membrane, and that Cys226 and Cys262 are located in or near a UDP binding site.

Alanine↗
PubMed2001

Group C streptococcal meningitis: case report and review of the literature.

Group C streptococci are a common cause of epidemic bacterial infection in animals. These organisms are a rare but frequently fatal cause of meningitis in humans. We report the case of a 13-year-old girl with meningitis caused by a group C Streptococcus (Streptococcus zooepidemicus) successfully treated with vancomycin and third generation cephalosporins. We also review cases of group C streptococcal meningitis reported previously.

Adolescent↗
PubMed2000

Streptococcus infantarius sp. nov., Streptococcus infantarius subsp. infantarius subsp. nov. and Streptococcus infantarius subsp. coli subsp. nov., isolated from humans and food.

Eighteen strains isolated from human specimens or from food products were characterized as atypical variants of mannitol-negative Streptococcus bovis. They were tested for extended biochemical criteria, ribotyping and DNA-DNA hybridization in order to define their taxonomic status. These strains were demonstrated to constitute a DNA relatedness group that includes strains of DNA group 4 of Farrow et al. (1984). Comparative analysis of 16S rRNA sequences demonstrated that these strains represent a new species which belongs to the Streptococcus bovis/Streptococcus equinus complex and which has been provisionally named S. infantarius by Bouvet et al. (1997). Biotyping and ribotyping allowed differentiation of these strains from the aesculin-positive strains of S. bovis belonging to the previously described biotypes I, II.1 and II.2. The results of the ribotyping and hybridization assays demonstrated the presence of two different DNA subgroups within the 18 strains. On the basis of these data, the names S. infantarius subsp. infantarius (aesculin-negative for five strains out of seven, including the type strain HDP 90056T = NCDO 599T) and S. infantarius subsp. coli (aesculin-positive, reference strain HDP 90248 = NCDO 2620) are proposed as the names for these two subspecies within the S. infantarius species.

Animals↗
PubMed1994

Epizootic pneumonia in nutria.

This report highlights current knowledge regarding the aetiology, diagnosis and management of nutria (Myocastor coypus Molina 1792) with spontaneous infectious pneumonia. Bacteriological evidence supports the view that Streptococcus zooepidemicus could be the specific pathogen, although other bacteria were also isolated. Attempts at virus isolation were unsuccessful. Pneumonia has rapidly become established as one of the major, life-threatening bacterial diseases, ranking in importance with gastroenteritis infections.

Animals↗
PubMed2005

Epidemic glomerulonephritis due to Streptococcus zooepidemicus in Nova Serrana, Brazil.

BACKGROUND: In 1998, there was a large outbreak of acute glomerulonephritis in Nova Serrana, Brazil, caused by group C Streptococcus zooepidemicus. This article reviews the characteristics of the outbreak and some aspects of the patients' follow-up. METHODS: We describe clinical characteristics of patients with acute nephritis. Using case-control studies, we identified the source of infection. Cultures of oropharyngeal swabs from patients were performed. Of 135 patients identified in 1998, available patients were reexamined in a prospective study after 2 and 5 years. RESULTS: Lancefield group C S. zooepidemicus was identified as the causative organism and linked to the consumption of cheese produced from unpasteurized milk. Of the original group of 134 patients, 4 died in the acute phase and 5 (3.7%) required chronic dialysis. After 2 years, of the 69 cases reevaluated, 94% were adults (mean +/- standard error age: 39 +/- 2 years); we found arterial hypertension in 42% (N= 27/64) of the patients, reduced creatinine clearance (<80 mL/min/1.73 m(2)) in 30% (N= 20/67), and increased microalbuminuria (>20 microg/min) in 34% (N= 22/65). Preliminary data at 5-year follow-up suggest that the percentage of patients with creatinine clearance lower than 60 mL/min increased from 9% to 15%. CONCLUSION: This article highlights the dangers of consuming unpasteurized dairy products. Follow-up of patients with epidemic poststreptococcal glomerulonephritis due to S. zooepidemicus show that a considerable proportion present hypertension, reduced renal function, and increased microalbuminuria.

Adolescent↗
PubMedDate not supplied

Detection of bacteria in equine synovial fluid by use of the polymerase chain reaction.

Equine synovial fluid aliquots were inoculated with Salmonella enteritidis, Escherichia coli, Actinobacillus equuli, Staphylococcus aureus, and Streptococcus zooepidemicus to obtain approximate concentrations of 1000, 100, 10, and 1 colony forming U/mL. Synovial fluid aliquots were also inoculated with an unquantitated inoculum of Bacteroides fragilis and Clostridium perfringens. Inoculated synovial fluid was incubated in trypticase-soy broth or Columbia broth for approximately 12 hours. Then aliquots were removed for DNA extraction and polymerase chain reaction (PCR) analysis for detection of a 531 base-pair segment of bacterial DNA corresponding to a region of the 16S ribosomal gene. Duplicate samples of inoculated synovial fluid were prepared for microbial culture. Bacteria were detected in all samples inoculated with bacteria but not in control synovial fluid samples. Under experimental conditions there was no difference between microbial culture and PCR analyses for detection of bacteria. Experimentally, PCR was able to detect bacteria in synovial fluid within 24 hours of inoculation.

Actinobacillus↗
PubMedDate not supplied

Arthroscopic treatment of temporomandibular joint sepsis in a horse.

OBJECTIVE: To report arthroscopic debridement and lavage of a septic temporomandibular joint (TMJ) in a horse. DESIGN: Clinical case report. ANIMALS: A 12-year-old Thoroughbred mare. METHODS: Arthroscopic investigation of the dorsal joint pouch of the right TMJ was made through a stab incision into the dorsocaudal compartment. Mechanized resection of synovium and fibrinous debris combined with copious lavage, and intra-articular and systemic antibiotic administration was used to treat the septic TMJ. RESULTS: Arthroscopic debridement and lavage of the TMJ, in combination with intra-articular and systemic antimicrobials resulted in resolution of sepsis. Eight months post-operatively, there was no clinical evidence of degenerative joint disease or ankylosis of the TMJ. CONCLUSION: TMJ sepsis is rare in horses, however, standard arthroscopic equipment can be used in the management of this condition with minimal complications. CLINICAL RELEVANCE: Arthroscopic debridement and lavage should be considered for evaluation and initial treatment of TMJ sepsis in horses.

Animals↗
PubMed2006

Mandibular condylectomy and meniscectomy for the treatment of septic temporomandibular joint arthritis in a horse.

OBJECTIVE: To report use of mandibular condylectomy for treatment of advanced degenerative joint disease of the temporomandibular joint (TMJ) caused by sepsis. DESIGN: Clinical case report. ANIMALS: Two-year-old Noriker filly. METHODS: Computed tomography (CT) was used to confirm advanced degenerative joint disease of the left TMJ and for follow-up after mandibular condylectomy and removal of necrotic meniscus. RESULTS: Painful swelling (3 weeks duration) with drainage located just caudal to the left lateral canthus of the eye was associated with atrophy of the left masseter muscle, masticatory problems, and inappetence. There was incisor malocclusion with a 1.4 cm resting lateral mandibular deviation to the right and inability to open the mouth more than a few centimeters. Left mandibular condylectomy combined with meniscectomy and thorough debridement of the septic left TMJ resulted in resolution of clinical signs and complete return of function. Streptococcus zooepidemicus, intermediately resistant to penicillin and subsequently to enrofloxacin, was isolated from the wound. Regeneration of a mandibular "pseudocondyle" was evident on CT at 4 months. At 4 months and 1 year the filly had maximal mouth opening >10 cm and no malocclusion. CONCLUSION: Mandibular condylectomy can be used to facilitate management of septic TMJ arthritis. There was no radiologic or clinical evidence of TMJ ankylosis >1 year after meniscal removal. CLINICAL RELEVANCE: Mandibular condylectomy, including meniscectomy, is an acceptable treatment option for advanced TMJ septic arthritis and allowed return of normal masticatory function.

Animals↗
PubMed1996

Allelic variation of the streptokinase gene in beta-hemolytic streptococci group C and G isolates of human origin.

Genetic diversity of the streptokinase gene (sk) from 36 strains of S. equisimilis and 54 strains of group G streptococci was examined. The strains were isolated from patients with various streptococcal disease manifestations and healthy carriers. The region of the gene that corresponds to amino acid residues 174-244, was PCR amplified. The amplified product was subjected to MluI, PvuII, DraI and DdeI digestion. Based on the restriction enzyme digestion patterns nine sk alleles were recognized. There was no correlation between the various sk gene alleles and streptococcal disease manifestations. Three of the nine sk gene alleles, sk4, sk7, and sk8, were detected earlier among group A streptococci. The other six alleles were unique to S. equisimilis and group G streptococci. The most common alleles were sk5, found in 21/90 (23%) and sk10 detected in 43/90 (47%) of the strains. Alleles sk1 and sk2, the most frequent among group A streptococci, were not found among the strains in the present investigation. Thus, it appears that the sk gene has been evolving in line with other species distinguishing features of the streptococci.

Alleles↗