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Jeremy P Burton

Publications and source records attributed to Jeremy P Burton.

12 recordsLinked to original sources
PubMed2006

Salivaricin A2 and the novel lantibiotic salivaricin B are encoded at adjacent loci on a 190-kilobase transmissible megaplasmid in the oral probiotic strain Streptococcus salivarius K12.

The commercial probiotic Streptococcus salivarius strain K12 is the prototype of those S. salivarius strains that are the most strongly inhibitory in a standardized test of streptococcal bacteriocin production and has been shown to produce the 2,368-Da salivaricin A2 (SalA2) and the 2,740-Da salivaricin B (SboB) lantibiotics. The previously uncharacterized SboB belongs to the type AII class of lantibiotic bacteriocins and is encoded by an eight-gene cluster. The genetic loci encoding SalA2 and SboB in strain K12 have been fully characterized and are localized to nearly adjacent sites on pSsal-K12, a 190-kb megaplasmid. Of 61 strongly inhibitory strains of S. salivarius, 19 (31%) were positive for the sboB structural gene. All but one (strain NR) of these 19 strains were also positive for salA2, and in each of these cases of double positivity, the two loci were separated by fewer than 10 kb. This is the first report of a single streptococcus strain producing two distinct lantibiotics.

Bacterial Proteins↗
PubMed2006

Megaplasmids encode differing combinations of lantibiotics in Streptococcus salivarius.

Streptococcus salivarius strains commonly produce bacteriocins as putative anti-competitor or signalling molecules. Here we report that bacteriocin production by the oral probiotic strain S. salivarius K12 is encoded by a large (ca. 190 kb) plasmid. Oral cavity transmission of the plasmid from strain K12 to a plasmid-negative variant of this bacterium was demonstrated in two subjects. Tests of additional S. salivarius strains showed large (up to ca. 220 kb) plasmids present in bacteriocin-producing isolates. Various combinations (up to 3 per plasmid) of loci encoding the known streptococcal lantibiotics salivaricin A, salivaricin B, streptin and SA-FF22 were localised to these plasmids. Since all bacteriocin-producing strains of S. salivarius tested to date appear to harbour plasmids, it appears that they may function as mobile repositories for bacteriocin loci, especially those of the lantibiotic class.

Bacterial Proteins↗
PubMed2006

Safety assessment of the oral cavity probiotic Streptococcus salivarius K12.

Streptococcus salivarius is a prominent member of the oral microbiota and has excellent potential for use as a probiotic targeting the oral cavity. In this report we document safety data relating to S. salivarius K12, including assessment of its antibiogram, metabolic profiles, and virulence determinants, and we examine the microbial composition of saliva following the dosing of subjects with K12.

Anti-Bacterial Agents↗
PubMed2005

Complexity of vaginal microflora as analyzed by PCR denaturing gradient gel electrophoresis in a patient with recurrent bacterial vaginosis.

OBJECTIVE: Gardnerella vaginalis has long been the most common pathogen associated with bacterial vaginosis (BV). We aimed to test our hypothesis that symptoms and signs of BV do not necessarily indicate colonization by this organism, and often will not respond to standard metronidazole or clindamycin treatment. METHODS: Using a relatively new molecular tool, PCR denaturing gradient gel electrophoresis (DGGE), the vaginal microflora of a woman with recalcitrant signs and symptoms of BV was investigated over a 6-week timeframe. RESULTS: The vagina was colonized by pathogenic enterobacteriaceae, staphylococci and Candida albicans. The detection of the yeast by PCR-DGGE is particularly novel and enhances the ability of this tool to examine the true nature of the vaginal microflora. The patient had not responded to antifungal treatment, antibiotic therapy targeted at anaerobic Gram-negative pathogens such as Gardnerella, nor daily oral probiotic intake of Lactobacillus rhamnosus GG. The failure to find the GG strain in the vagina indicated it did not reach the site, and the low counts of lactobacilli demonstrated that therapy with this probiotic did not appear to influence the vaginal flora. CONCLUSIONS: BV is not well understood in terms of its causative organisms, and further studies appear warranted using non-culture, molecular methods. Only when the identities of infecting organisms are confirmed can effective therapy be devized. Such therapy may include the use of probiotic lactobacilli, but only using strains which confer a benefit on the vagina of pre- and postmenopausal women.

Candida albicans↗
PubMed2005

A preliminary survey of Atopobium vaginae in women attending the Dunedin gynaecology out-patients clinic: is the contribution of the hard-to-culture microbiota overlooked in gynaecological disorders?

Preliminary studies have indicated that the recently described bacterium Atopobium vaginae may have an association with bacterial vaginosis (BV). Fifty-five women attending the gynaecology out-patient's clinic were tested for the presence of this micro-organism, Gardnerella vaginalis, Mobiluncus and Bacteroides species by polymerase chain reaction (PCR)-based assays. The frequency of detection was 40%. PCR detection of Gardnerella vaginalis with A. vaginae, occurred in 50% of A. vaginae-positive cases. Due to the high detection rate of A. vaginae we believe that it is important to determine whether this and other hard-to-culture microorganisms have a role in gynaecological disorders.

Actinobacteria↗
PubMed2005

Non-culture-based analysis of bacterial populations from patients with chronic rhinosinusitis.

Middle meatus aspirates from patients with chronic rhinosinusitis were analyzed by bacterial culture, denaturing gradient gel electrophoresis (DGGE), and antibiotic sensitivity techniques. DGGE detected a greater bacterial diversity than culture methods. Although resistance to antibiotics was low, there was evidence of changes in the composition of the bacterial microbiota over time, and the presence of noncultured bacteria was demonstrated.

Bacteria↗
PubMed2004

Novel insight into the vaginal microflora in postmenopausal women under hormone replacement therapy as analyzed by PCR-denaturing gradient gel electrophoresis.

OBJECTIVES: A study was conducted to use new molecular technologies to identify the vaginal bacterial species of postmenopausal women under oral estrogen therapy (Premarin-conjugated equine estrogen, CEE). STUDY DESIGN: Nineteen postmenopausal women under CEE treatment were recruited and their vaginal flora were analyzed during 3 months, using polymerase chain reaction in combination with denaturing gradient gel electrophoresis (DGGE) and sequencing of DNA fragments. RESULTS: Sixty-eight percent of the women presented with a 'Normal' Nugent score at the first sampling time (d0). All the subjects had bacterial species detected in their vaginal flora. Lactobacillus species were detected in all samples. Moreover, 53% of the women had lactobacilli exclusively at d0. Two Lactobacillus species were dominant, and were recovered from the majority of samples (L. iners and L. crispatus). Forty-four percent of the samples also contained other bacterial species, which were potential urogenital pathogens. Candida albicans was detected in 26% of the subjects. The vaginal flora of the women under CEE treatment were different from that of postmenopausal women not receiving hormone therapy, but very similar to premenopausal women. CONCLUSIONS: The present study indicates that one benefit from hormone replacement therapy (HRT) is the restoration of a lactobacilli vaginal flora associated with a protective effect against urogenital infections.

Adult↗
PubMed2004

Surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS): a new proteomic urinary test for patients with urolithiasis.

SELDI-TOF-MS is a highly sensitive protein-analysis tool capable of detecting minute protein profile differences between biological samples. As proteins have been associated with urinary tract calculi, protein-based urinalysis may offer insights into their diagnosis. The purpose of this study was to evaluate SELDI-TOF-MS as a potential method for identifying urinary biomarkers of urolithiasis. Midstream sterile urine samples were obtained from 25 male patients with a confirmed diagnosis of urolithiasis (test group) and 25 male subjects with no known history of the disease (controls). Urinary levels of oxalate, total protein, albumin, and osteopontin were determined. Protein profiles were generated using SELDI-TOF-MS.SELDI-TOF-MS profiling revealed a relationship between protein peak intensities at 67 and 24 kDa that differed between the two groups. The ratio of p67:p24 was found to be less than 1.0 in all of the control samples (mean 0.26), while 18 out of 25 (72%) of the test group samples displayed a ratio greater than 1.0 (total group mean 4.75, P<0.001). Albumin, total protein, and oxalate levels were higher in the test group than the controls. Although SELDI-TOF-MS is not yet in widespread use in hospital and diagnostic laboratories, this system represents a promising new method for rapidly identifying patients with urolithiasis.

Albumins↗
PubMed2003

Oxalate-degrading enzymes from Oxalobacter formigenes: a novel device coating to reduce urinary tract biomaterial-related encrustation.

BACKGROUND AND PURPOSE: The long-term placement of biomaterials within the urinary tract is limited by the development of encrustation. In a noninfected urinary environment, encrustation often results from the deposition of calcium oxalate on the biomaterial surface. There is an association between the absence of Oxalobacter formigenes, a commensal colonic bacterium capable of degrading oxalate, and calcium oxalate stone formation. This pilot study was designed to evaluate several oxalate-degrading enzymes produced by O. formigenes as a potential biomaterial coating to reduce urinary tract encrustation. MATERIALS AND METHODS: Circular silicone disks of 6-mm diameter were incubated for 48 hours in oxalylcoenzyme A decarboxylase (OXC), formyl-coenzyme A transferase (FRC), and coenzyme A, while control disks were incubated in distilled water. The adsorption of OXC and FRC was assessed using enhanced chemiluminescence (ECL) and atomic force microscopy (AFM). Coated and uncoated disks (20 of each) were implanted in the bladders of 40 female New Zealand White rabbits. After 30 days, the disks were recovered, and the degree of encrustation on the polymer surface was evaluated utilizing dry weight measurement, calcium atomic absorption spectroscopy (AAS), and scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX). RESULTS: Both ECL and AFM demonstrated coating of the silicone disks with OXC and FRC. The mean dry weights of the coated and control disks following explantation were 0.591 +/- 0.438 g and 0.747 +/- 0.428 g, respectively (P = 0.307). The mean weight of calcium on the coated and control disks, as determined by AAS, was 154.1 +/- 96.25 mg and 258 +/- 181.35 mg, respectively (P = 0.008). CONCLUSIONS: The use of oxalate-degrading enzymes from O. formigenes to coat urinary biomaterials represents a novel paradigm to reduce biomaterial-related encrustation. Coating of silicone with oxalate-degrading enzymes from O. formigenes results in a modest reduction in encrustation with no apparent toxicity. Further studies are warranted.

Animals↗
PubMed2003

Improved understanding of the bacterial vaginal microbiota of women before and after probiotic instillation.

The vaginal bacterial microbiota of 19 premenopausal women was examined by PCR-denaturing gradient gel electrophoresis (DGGE) and sequencing of the V2-V3 region of the 16S rRNA gene. Ten of the women were studied further to investigate the effect and persistence of vaginally inserted capsules containing viable lactobacilli. PCR-DGGE indicated that most subjects had a microbiota represented by one to three dominant DNA fragments. Analysis of these fragments revealed that 79% of the women possessed sequences with high levels of similarity to Lactobacillus species sequences. Sequences homologous to Lactobacillus iners sequences were the most common and were detected in 42% of the women tested. Alteration of the vaginal microbiota could be detected by PCR-DGGE in several women after the instillation of lactobacilli. Additionally, randomly amplified polymorphic DNA analysis of lactobacilli isolated from selective media demonstrated that the exogenous strains could be detected for up to 21 days in some subjects. This study demonstrates that non-culture-based techniques, such as PCR-DGGE, are useful adjuncts for studies of the vaginal microbiota.

Adult↗
PubMed2002

Evaluation of the bacterial vaginal flora of 20 postmenopausal women by direct (Nugent score) and molecular (polymerase chain reaction and denaturing gradient gel electrophoresis) techniques.

To monitor the bacterial vaginal microflora of postmenopausal women, several approaches were used: (1) Nugent scoring of Gram-stained smears from vaginal swabs; (2) testing for bacteria, using specific polymerase chain reaction (PCR) primers; (3) PCR-denaturing gradient gel electrophoresis (DGGE) analysis of total bacterial DNA, amplified using eubacterial and Lactobacillus-specific primers; and (4) sequence analysis of amplified DNA fragments of interest from denaturing gradient gels. Of 20 women studied, 70% had either intermediate-grade bacterial colonization or bacterial vaginosis (BV), as defined by Nugent criteria, at the first sampling point. Subjects with normal Nugent scores had >/=1 species of Lactobacillus detected by sequencing of dominant DNA fragments from denaturing gradient gels generated using eubacterial primers. Samples from women with Nugent scores that indicated BV had varied bacterial DGGE profiles, which emphasizes the diverse nature of such infections. This study indicates that asymptomatic BV appears to be much more common than is currently perceived; these findings may have implications for the health of postmenopausal women.

Adult↗