Patients not taking a previously prescribed bone active medication now prescribed medication through Ontario FLS

In an Ontario fracture liaison service (FLS), we compared medication prescription rates among patients not taking a previously prescribed bone active medication to those with no previous prescription. Prescription rates were similar between these two groups of patients. The FLS provided a secondary opportunity for patients to initiate bone active medication.

PURPOSE

We compared bone active medication prescription rates among patients presenting to an Ontario fracture liaison service (FLS) who reported not taking a previously prescribed bone active medication to those with no history of prescription.

METHODS

Eligible patients were those screened in 39 fracture clinics between July 1, 2017, and September 15, 2019, who were not taking bone active medication at the time of screening and classified as high risk for future fracture based on CAROC or FRAX. Sociodemographic and clinical risk factor variables were assessed at screening. Bone active medication prescription rate was assessed within 6 months of screening and defined as having received a prescription for the medication from either a specialist or primary care provider. In cases where a specialist report was not available, patient self-reported data were collected. The chi-square test of independence was used to assess differences in prescription rates.

RESULTS

Of 17,575 patients screened, eligible patients were 350 with a previous prescription and 2644 without a previous prescription. Compared with patients who reported no previous prescription, those who had a previous prescription were older, more likely to be female and to report a previous fracture, and less likely to smoke. There was no statistically significant difference between the medication prescription rate of patients with a previous prescription (73.7%) compared to patients with no previous prescription (70.7%) (p = 0.157).

CONCLUSION

A large jurisdiction-wide FLS approach provided a secondary opportunity to patients who were not taking a previously prescribed bone active medication to initiate that medication.

Patients 80 + have similar medication initiation rates to those aged 50-79 in Ontario FLS

Among individuals presenting to an Ontario FLS, we compared bone active medication initiation rates of patients 80 years and older with those 50-79 years old. After accounting for fracture risk status, there was no statistically significant difference in medication initiation rates between the two age groups INTRODUCTION: A Fracture Liaison Service (FLS) offers post-fracture services to individuals over the age of 50 years and could potentially address age inequities in pharmacotherapy often observed for older adults. Among individuals presenting to an Ontario FLS and classified as being at high risk for future fracture, our objective was to compare bone active medication initiation rates of patients 80 years and older with those 50-79 years old.

METHODS

In 39 FLS fracture clinics across Ontario, Canada, fracture prevention coordinators identified, assessed, and facilitated the referral of eligible patients for bone densitometry, fracture risk assessment, and implementation of pharmacotherapy in patients classified as high risk for future fracture. Variables assessed at baseline included age, sex, marital status, living location, fracture location, history of previous fracture, parent's history of hip fracture, history of falls, and fracture risk status. At 6 months, bone active medication initiation was assessed in patients classified as high risk for future fracture. The Chi-square test of independence was used to compare medication initiation rates between patients 80 + and those 50-79 years old.

RESULTS

Our sample size consisted of 808 patients aged 50-79 years and 346 aged 80 + years. After accounting for fracture risk status, there was no statistically significant difference in medication initiation rates of patients 50-79 and 80 + years old (76.9% versus 73.7%, p = 0.251).

CONCLUSION

A systematic approach to identifying patients at high risk for future fracture and tailoring treatment recommendations to these patients appeared to eliminate differences in treatment initiation rates based on older age.

Is a 'healthy diet' and a 'calcium-rich diet' the same thing? Qualitative study examining perceptions of a calcium-rich diet in individuals who have received bone health education

BACKGROUND

In the present study, we aimed to (i) examine perceptions of achieving calcium and vitamin D recommended dietary allowance (RDA) and (ii) determine how participants talked about food in relation to RDA recommendations.

METHODS

Participants aged ≥50 years who were prescribed osteoporosis medication and received two modes of bone health education were eligible. Relying on a qualitative description design, we interviewed participants 1 month after they had attended an education session and received a self-management booklet. Calcium and vitamin D intakes were estimated by in-depth questions about diet and supplements and compared with perceptions of achieved RDA levels. Interview transcripts were analysed based on an analytic hierarchical process.

RESULTS

Forty-five participants (29 reporting previous fragility fractures) were included. Calcium and vitamin D RDA appeared to be potentially achieved by 64% and 93% of participants, respectively, primarily because of reliance on supplements. Few participants talked about vitamin D in relation to food intake and 49% of participants were unclear about the calcium content of food. Most considered that a healthy diet was equivalent to a calcium-rich diet. We noted no differences in our findings in the subset of individuals with fragility fractures.

CONCLUSIONS

Despite reporting a prescription for osteoporosis medication and receiving bone health education, a substantial number of individuals appeared to have sub-optimal calcium levels. This may be attributed to the challenge of achieving RDA with diet alone and the misconception of a healthy diet as a calcium-rich diet.

The impact of fragility fractures on work and characteristics associated with time to return to work

We examined the impact of fragility fractures on the work outcomes of employed patients. The majority successfully returned to their previous jobs in a short amount of time, and productivity loss at work was low. Our findings underscore the fast recovery rates of working fragility fracture patients.

INTRODUCTION

The purpose of this study is to describe the impact of fragility fractures on the work outcomes of patients who were employed at the time of their fracture.

METHODS

A self-report anonymous survey was mailed to fragility fracture patients over 50 who were screened as part of the quality assurance programs of fracture clinics across 35 hospitals in Ontario, Canada. Measures of return to work (RTW), at-work productivity loss (Work Limitations Questionnaire), and sociodemographic, fracture-related, and job characteristics were included in the survey. Kaplan-Meier estimates of the cumulative proportion of patients still off work were computed. Factors associated with RTW time following a fragility fracture were examined using Cox proportional hazards modeling.

RESULTS

Of 275 participants, 242 (88 %) returned to work. Of these, the median RTW time was 20.5 days. About 86 % returned to the same job, duties, and hours as before their injury. Among full-time workers, the median number of lost hours due to presenteeism was 2.9 h (Q1-Q3 0.4-8.1 h). The median cost of presenteeism was $75.30 based on the month prior to survey completion. In multivariable analyses, female gender, needing surgery, and medium/heavy work requirements were associated with longer RTW time. Earlier RTW time was associated with elbow fracture and feeling completely better at time of survey completion.

CONCLUSIONS

The majority of fragility fracture patients successfully returned to their previous jobs in a short amount of time, and productivity loss at work was low. Our findings underscore their fast recovery rates and give reason for optimism regarding the resilience of this population.

An infinite-server queue subject to an extraneous phase process and related models

We consider an infinite-server queueing system in an extraneous environment. Initially it is shown that the systems of interest can be decomposed into a two-stage system. The primary system is an infinite-server queue with many customer types subject to a clearing mechanism. The secondary system is a special type of bulk-arrival, infinite-server queue. We derive results for the primary and secondary systems separately and combine the results to find the mean steady-state behavior of the original system.

Anaerobic (bacterial) vaginosis and premalignant disease of the cervix

Nitrosamines are carcinogenic substances found in cigarette smoke, and it is known that female smokers have an increased risk of cervical carcinoma and premalignant change. Nitrosamines may also be formed due to the combination of amines and nitrites in an acidic medium. This study has shown a statistically significant association between anaerobic vaginosis which produce amines and cervical intraepithelial neoplasia 2 and 3. In addition nitrate reducing organisms are found in the acidic lower genital tract in a significant number of cases. It is therefore theoretically possible that nitrosamines may be an important agent in the development of premalignant disease of the cervix.

The Campylobacter jejuni general glycosylation system is important for attachment to human epithelial cells and in the colonization of chicks

It has recently been shown that the enteropathogenCampylobacter jejunihas anN-linked generalproteinglycosylation pathway (Pgl) that modifies many of the organism's proteins. To determine the role of theN-linked general glycosylation inC jejuni, the authors studied thepglHgene, which shows high similarity to a family of sugar transferases.pglHmutants were constructed in strains 81116 and 11168H. Both mutants were shown to be deficient in their ability to glycosylate a number ofC. jejuniproteins, but their lipooligosaccharide and capsule were unaffected. ThepglHmutants had significantly reduced ability to adhere to and invade human epithelial Caco-2 cells. Additionally, the 81116pglHmutant was severely affected in its ability to colonize chicks. These results suggest that glycosylation is important for the attachment ofC. jejunito human and chicken host cells and imply a role for glycoproteins in the pathogenesis ofC. jejuni.

Chlamydia trachomatis infection in a colposcopy unit: an audit of a fast track referral system for infected patients to a genitourinary medicine department and a survey of patients' demography, clinical findings and partner details

We had previously shown that screening and treating patients for Chlamydia trachomatis prior to termination of pregnancy significantly reduces postoperative morbidity. Our success led us to consider screening women attending our colposcopy unit and this was introduced in 1998. However, it became apparent that a formal protocol was needed for managing women who had positive results to ensure that all patients and their partners were adequately treated. An interdepartmental protocol was devised for fast track referral of infected patients to the Genitourinary Medicine (GUM) clinic Health Advisor who arranged immediate treatment and partner notification. A re-audit, presented here, has shown that the introduction of the protocol has resulted in all infected patients receiving adequate treatment and partner notification with minimal use of doctor time or disruption of routine GUM services. We suggest that our system is effective and could be extended to other clinics where chlamydia screening is carried out.

Whole genome comparison of Campylobacter jejuni human isolates using a low-cost microarray reveals extensive genetic diversity

Campylobacter jejuni is the leading cause of bacterial food-borne diarrhoeal disease throughout the world, and yet is still a poorly understood pathogen. Whole genome microarray comparisons of 11 C. jejuni strains of diverse origin identified genes in up to 30 NCTC 11168 loci ranging from 0.7 to 18.7 kb that are either absent or highly divergent in these isolates. Many of these regions are associated with the biosynthesis of surface structures including flagella, lipo-oligosaccharide, and the newly identified capsule. Other strain-variable genes of known function include those responsible for iron acquisition, DNA restriction/modification, and sialylation. In fact, at least 21% of genes in the sequenced strain appear dispensable as they are absent or highly divergent in one or more of the isolates tested, thus defining 1300 C. jejuni core genes. Such core genes contribute mainly to metabolic, biosynthetic, cellular, and regulatory processes, but many virulence determinants are also conserved. Comparison of the capsule biosynthesis locus revealed conservation of all the genes in this region in strains with the same Penner serotype as strain NCTC 11168. By contrast, between 5 and 17 NCTC 11168 genes in this region are either absent or highly divergent in strains of a different serotype from the sequenced strain, providing further evidence that the capsule accounts for Penner serotype specificity. These studies reveal extensive genetic diversity among C. jejuni strains and pave the way toward identifying correlates of pathogenicity and developing improved epidemiological tools for this problematic pathogen.

Deciphering Campylobacter jejuni cell surface interactions from the genome sequence

The completion of the Campylobacter jejuni genome sequence is a landmark in Campylobacter research. Discoveries directly arising from these data include the identification of a capsular polysaccharide, extensive capacity for phase variable gene expression and lipo-oligosaccharide structural phase variation. The recent identification of a unique system of general protein glycosylation in C. jejuni, a C. jejuni protein that is translocated into eukaryotic cells, and plasmid-encoded components of a putative type IV secretion system are likely to be significant in terms of the host-pathogen interaction.

Warfarin skin necrosis: local and systemic factors

Warfarin induced skin necrosis occurs in 0.01-0.1% of warfarin treated patients. The usual presentation is that of painful lesions developing in obese women after the initiation of warfarin treatment. The lesions usually evolve into full thickness skin necrosis within a few days. Although the exact mechanism is not totally clear, low levels of Protein C or S, either functional or inherited, are associated with many of the cases. We report the case of a 17-year-old patient treated with warfarin because of iliofemoral deep vein thrombosis post abortion. The patient developed several huge haemorrhagic blisters on the affected leg. The condition rapidly developed into full thickness skin and fat necrosis. The necrotic lesions were excised and eventually covered with skin graft. The combination of the patient tendency towards hyper-coagulation and the local factors is discussed.

Phase variation of a beta-1,3 galactosyltransferase involved in generation of the ganglioside GM1-like lipo-oligosaccharide of Campylobacter jejuni

Ganglioside mimicry by Campylobacter jejuni lipo-oligosaccharide (LOS) is thought to be a critical factor in the triggering of the Guillain-Barré and Miller-Fisher syndrome neuropathies after C. jejuni infection. The combination of a completed genome sequence and a ganglioside GM1-like LOS structure makes C. jejuni NCTC 11168 a useful model strain for the identification and characterization of the genes involved in the biosynthesis of ganglioside-mimicking LOS. Genome analysis identified a putative LOS biosynthetic cluster and, from this, we describe a putative gene (ORF Cj1139c), which we have termed wlaN, with a significant level of similarity to a number of bacterial glycosyltransferases. Mutation of this gene in C. jejuni NCTC 11168 resulted in a LOS molecule of increased electrophoretic mobility, which also failed to bind cholera toxin. Comparison of LOS structural data from wild type and the mutant strain indicated lack of a terminal beta-1,3-linked galactose residue in the latter. The wlaN gene product was demonstrated unambiguously as a beta-1,3 galactosyltransferase responsible for converting GM2-like LOS structures to GM1-like by in vitro expression. We also show that the presence of an intragenic homopolymeric tract renders the expression of a functional wlaN gene product phase variable, resulting in distinct C. jejuni NCTC 11168 cell populations with alternate GM1 or GM2 ganglioside-mimicking LOS structures. The distribution of wlaN among a number of C. jejuni strains with known LOS structure was determined and, for C. jejuni NCTC 12500, similar wlaN gene phase variation was shown to occur, so that this strain has the potential to synthesize a GM1-like LOS structure as well as the ganglioside GM2-like LOS structure proposed in the literature.

Campylobacter lanienae sp. nov., a new species isolated from workers in an abattoir

Campylobacter-like organisms were isolated from the faeces of healthy individuals during a hygiene survey of abattoir workers. The strains, which exhibited characteristics of Campylobacter, being non-glucose-fermenting, oxidase- and catalase-positive, Gram-negative, motile rods, were identified to the genus level by a PCR assay. Nucleotide sequence analysis of the 16S rRNA gene, DNA homology experiments and determination of G + C content demonstrated that they constituted a previously undescribed species, whose nearest phylogenetic neighbours were Campylobacter hyointestinalis subsp. hyointestinalis, Campylobacter fetus and Campylobacter mucosalis. The name Campylobacter lanienae sp. nov. is proposed for this taxon and species-specific PCR primers were evaluated which will find use in the study of its epidemiology, prevalence and pathogenicity.

Multiple N-acetyl neuraminic acid synthetase (neuB) genes in Campylobacter jejuni: identification and characterization of the gene involved in sialylation of lipo-oligosaccharide

N-acetyl neuraminic acid (NANA) is a common constituent of Campylobacter jejuni lipo-oligosaccharide (LOS). Such structures often mimic human gangliosides and are thought to be involved in the triggering of Guillain-Barré syndrome (GBS) and Miller-Fisher syndrome (MFS) following C. jejuni infection. Analysis of the C. jejuni NCTC 11168 genome sequence identified three putative NANA synthetase genes termed neuB1, neuB2 and neuB3. The NANA synthetase activity of all three C. jejuni neuB gene products was confirmed by complementation experiments in an Escherichia coli neuB-deficient strain. Isogenic mutants were created in all three neuB genes, and for one such mutant (neuB1) LOS was shown to have increased mobility. C. jejuni NCTC 11168 wild-type LOS bound cholera toxin, indicating the presence of NANA in a LOS structure mimicking the ganglioside GM1. This property was lost in the neuB1 mutant. Gas chromatography-mass spectrometry and fast atom bombardment-mass spectrometry analysis of LOS from wild-type and the neuB1 mutant strain demonstrated the lack of NANA in the latter. Expression of the neuB1 gene in E. coli confirmed that NeuB1 was capable of in vitro NANA biosynthesis through condensation of N-acetyl-D-mannosamine and phosphoenolpyruvate. Southern analysis demonstrated that the neuB1 gene was confined to strains of C. jejuni with LOS containing a single NANA residue. Mutagenesis of neuB2 and neuB3 did not affect LOS, but neuB3 mutants were aflagellate and non-motile. No phenotype was evident for neuB2 mutants in strain NCTC 11168, but for strain G1 the flagellin protein from the neuB2 mutant showed an apparent reduction in molecular size relative to the wild type. Thus, the neuB genes of C. jejuni appear to be involved in the biosynthesis of at least two distinct surface structures: LOS and flagella.

Genetic and biochemical evidence of a Campylobacter jejuni capsular polysaccharide that accounts for Penner serotype specificity

Campylobacter jejuni, a Gram-negative spiral bacterium, is the most common bacterial cause of acute human gastroenteritis and is increasingly recognized for its association with the serious post-infection neurological complications of the Miller-Fisher and Guillain-Barré syndromes. C. jejuni lipopolysaccharide (LPS) is thought to be involved in the pathogenesis of both uncomplicated infection and more serious sequelae, yet the LPS remains poorly characterized. Current studies on C. jejuni suggest that all strains produce lipooligosaccharide (LOS), with about one-third of strains also producing high-molecular-weight LPS (referred to as O-antigen). In this report, we demonstrate the presence of the high-molecular-weight LPS in all C. jejuni strains tested. Furthermore, we show that this LPS is biochemically and genetically unrelated to LOS and is similar to group II and group III capsular polysaccharides. All tested kpsM, kpsS and kpsC mutants of C. jejuni lost the ability to produce O-antigen. Moreover, this correlated with serotype changes. We demonstrate for the first time that the previously described O-antigen of C. jejuni is a capsular polysaccharide and a common component of the thermostable antigen used for serotyping of C. jejuni.

Campylobacter coli strains with enlarged flagellin genes isolated from river water

A group of campylobacters isolated from river water were found to possess unusually large flagellin genes. Both phenotype and serology were consistent with identification as Campylobacter coli. Phylogenetic analysis of small (16S, rrs) and large subunit (23S, rrl) rRNA genes of a representative strain, NCTC 13006, demonstrated high levels of relatedness with C. jejuni and C. coli (99.1 and 98.3% similarity for 16S; 99.3 and 99.4% similarity for 23S). Large flagellin proteins were demonstrated by SDS-PAGE analysis. The flaA and flaB genes were sequenced and aligned with known campylobacter flagellin amino acid sequences. The encoded FlaA protein of the new group exhibited a high degree of divergence from other Campylobacter species. Within the central variable region of FlaA, a further hypervariable domain was identified containing characteristic repeated motifs. Separate pairwise alignments performed for the variable regions of the polypeptide indicated these large fla genes were more closely related to those of C. upsaliensis than to those of C. coli or C. jejuni.

PCR detection, identification to species level, and fingerprinting of Campylobacter jejuni and Campylobacter coli direct from diarrheic samples

Three sets of primers were designed for PCR detection and differentiation of Campylobacter jejuni and Campylobacter coli. The first PCR assay was designed to coidentify C. jejuni and C. coli based on their 16S rRNA gene sequences. The second PCR assay, based on the hippuricase gene sequence, identified all tested reference strains of C. jejuni and also strains of that species which lack detectable hippuricase activity. The third PCR assay, based on the sequence of a cloned (putative) aspartokinase gene and the downstream open reading frame, identified all tested reference strains of C. coli. The assays will find immediate application in the rapid identification to species level of isolates. The assays combine with a protocol for purification of total DNA from fecal samples to allow reproducible PCR identification of campylobacters directly from stools. Of 20 clinical samples from which campylobacters had been cultured, we detected C. jejuni in 17, C. coli in 2, and coinfection of C. jejuni and Campylobacter hyointestinalis in 1. These results were concordant with culture and phenotypic identification to species level. Strain typing by PCR-restriction fragment length polymorphism of the flagellin (flaA) gene detected identical flaA types in fecal DNA and the corresponding campylobacter isolate. Twenty-five Campylobacter-negative stool samples gave no reaction with the PCR assays. These PCR assays can rapidly define the occurrence, species incidence, and flaA genotypes of enteropathogenic campylobacters.

Polymerase chain reaction detection and speciation of Campylobacter upsaliensis and C. helveticus in human faeces and comparison with culture techniques

A polymerase chain reaction (PCR) assay based on the 16S rRNA gene and an improved DNA extraction procedure were developed for the direct detection and differentiation of Campylobacter upsaliensis and C. helveticus in seeded human faeces. The PCR assay was compared with culture detection by a membrane filter (MF) technique and on selective agar (SA) containing 8 mg l-1 cefoperazone. Both MF culture and the PCR assay detected 10(5) colony-forming units (cfu) g-1 faeces. Selective agar culture of some strains could detect as few as 10(3) cfu g-1 faeces. However, some strains were susceptible to cefoperazone and either failed to grow or were detected only with reduced sensitivity in the presence of the antibiotic. Detection by MF and SA both required 48-96 h incubation in a microaerobic atmosphere and did not specifically identify the isolate. By contrast, the PCR assay could be completed within 8 h and accurately identified the two phenotypically similar species, C. upsaliensis and C. helveticus.

Sequence similarities between large subunit ribosomal RNA gene intervening sequences from different Helicobacter species

When the 23S rRNA genes from several Helicobacter species were amplified by PCR and compared with similar amplicons derived from H. pylori, they were seen to be enlarged in size. Sequencing of these enlarged genes from H. mustelae, H. canis (two strains) and H. muridarum identified insertions of novel sequence (intervening sequences, IVSs) sized between 93 and 377 bp located at nt 545, in place of an 8-nt sequence in the conventionally sized H. pylori gene. These IVSs were not present elsewhere in the genome. All strains with such IVSs lacked intact 23S rRNA which was replaced by two fragment whose sizes were consistent with cleavage at either side of the particular IVS. The predicted secondary structures of the four IVSs were characterised by base pairing at the 5' and 3' ends to form a stem. The four IVSs exhibited significant sequence inter-relationships. Further relationships were also observed between them and similar elements in both small and large subunit rRNA genes of other Helicobacter and Campylobacter species. Alignment of each IVS with the other such elements identified blocks of related sequence consistent with insertion/deletion events, indicating possible evolutionary relationships.

Rapid identification by PCR of the genus Campylobacter and of five Campylobacter species enteropathogenic for man and animals

The nucleotide sequences for the 16S ribosomal RNA gene were compared for 33 species comprising the epsilon subdivision of the Proteobacteria (genera: Campylobacter, Helicobacter, Arcobacter and Wolinella). Regions specific for the genus Campylobacter and for five Campylobacter species important in human and/or veterinary medicine were identified. From these regions, PCR primer pairs were designed for use in species-specific identification. Primer pairs were validated against strains representing all taxa of campylobacter-like organisms. They did not amplify products other than from their five target species (C. upsaliensis, C. helveticus, C. fetus, C. hyointestinalis and C. lari), and they generated amplicons of defined size from large numbers of strains of those species. A primer pair suitable for identification of the genus Campylobacter was also identified and validated. This generated amplicons from all species of Campylobacter as well as from unnamed groups known to be within the genus, but not from any species or unnamed strains of Helicobacter, Arcobacter or Wolinella.

Molecular subtyping of prevalent M serotypes of Streptococcus pyogenes causing invasive disease

Reproducible methodologies and a scheme for high-resolution genotyping of Streptococcus pyogenes were defined with respect to a study of six predominant M serotypes causing invasive group A streptococcal disease in the United Kingdom. Serotype reference strains were compared with nine clinical isolates of each serotype from patients with diseases such as pneumonia, puerperal sepsis, toxic shock-like-syndrome, cellulitis, or necrotizing fasciitis. Four enzymes were evaluated for their discriminatory power in 16S rRNA gene-specific ribotyping. Discriminatory power was greatest with EcoRI, which generated serotype-specific ribotypes, and with SacI, which could subdivide strains of the same M serotype. Twenty-five combined ribotypes were found among the 60 strains, and the indices of discriminatory power (D values) of this method varied from 0.51 within serotype M1 to 0.98 within strains of serotype M5. Macrorestriction with the rarely cutting endonuclease SmaI and pulsed-field gel electrophoresis gave D values varying from 0.37 within serotype M1 to the maximal 1.0 within serotype M5. Comparison of macrorestriction profiles revealed various degrees of genetic heterogeneity within M serotypes. Strains of M1, M3, M6, and M11 exhibited clonally related macrorestriction profiles, while those of R28 and M5 strains were consistent with polyphyletic origin.

High-resolution genotyping of Campylobacter coli identifies clones of epidemiologic and evolutionary significance

Campylobacter coli strains from clinical and other sources were examined in terms of O (heat-stabile; HS) serotype and by several molecular typing techniques. Restriction fragment length polymorphism (RFLP) around the three 16S rRNA genes revealed 10 variants, none found in Campylobacter jejuni. RFLP analysis of a polymerase chain reaction amplicon generated from the flagellin gene (flaA) yielded 11 polymorphism groups, some of them linked to HS serotypes. Enlarged flaA genes, contributing three further polymorphisms, were detected in strains isolated from fresh water. Restriction of the genome with SmaI and pulsed-field gel electrophoresis was the most discriminatory typing method, detecting 33 macrorestriction profiles that subtyped within HS serotypes. The coincidence of HS serotype and the three genotypic markers identified clonal lines of evolutionary and epidemiologic significance.

Helicobacter pullorum sp. nov.-genotype and phenotype of a new species isolated from poultry and from human patients with gastroenteritis

Campylobacter-like organisms were isolated from the liver, duodenum and caecum of broiler and layer chickens, and from humans with gastroenteritis. They formed a unique DNA homology group and a polyphasic taxonomic analysis was made of 16 strains. Analysis of the nucleotide sequence of the 16S rRNA gene from seven of the strains identified them as belonging to a single species, within the genus Helicobacter. This conclusion was supported by the studies of relative DNA homology and of total protein electrophoretic patterns. The new species could be biochemically differentiated from other helicobacters and its ultrastructure in the electron microscope was typical of the genus except that the flagellum was not sheathed. We propose the name Helicobacter pullorum sp. nov. for this group. Like H. fennelliae or H. cinaedi it represents another non-gastric urease-negative Helicobacter species colonizing the lower bowel. Its isolation from the livers of chickens with vibrionic hepatitis is significant. We describe a species-specific PCR assay for H. pullorum sp. nov. which will facilitate its identification and further studies of its epidemiology.

An intervening sequence (IVS) in the 16S rRNA gene of the eubacterium Helicobacter canis

PCR amplicons enlarged by approximately 250bp were generated from the 16S rRNA (rrs) genes of certain strains of the recently described Helicobacter species, H. canis. The DNA sequence of the rrs gene of one such strain was determined, and it was shown that an intervening sequence (IVS) of 235bp followed nucleotide 199 in the rrs sequence. In four other H. canis strains, identical or similar IVSs were found, always at the same location in the rrs gene. The secondary structures of the RNA transcripts of the IVSs were predicted. They were characterised by the presence of a conserved stem-loop structure, a potential recognition site for RNA processing enzymes. Ribosomal RNA was compared from a strain of H. canis with and without the IVS-containing rrs gene. In the former 16S rRNA appeared as two fragments, whose sizes were consistent with cleavage at either side of the IVS, and which were not subsequently religated. The IVS sequence was not represented elsewhere in the H. canis genome. Its evolutionary significance is discussed.

Two types of 16S rRNA gene are found in Campylobacter helveticus: analysis, applications and characterization of the intervening sequence found in some strains

In the recently described species Campylobacter helveticus, two sizes of PCR amplicon were detected with primers homologous to conserved regions of the 16S rRNA gene. A conventionally sized gene was sequenced from the type strain, NCTC 12470, placing the new species as phylogenetically related to C. upsaliensis and the thermotolerant campylobacters. This nucleotide sequence enabled PCR primers to be designed for use in rapid molecular identification of C. helveticus and its closest phylogenetic relative, C. upsaliensis. When this assay was employed to characterize 22 'C. upsaliensis-like' isolates, twelve were identified as C. helveticus and nine as C. upsaliensis, in agreement with data obtained with a C. helveticus-specific DNA probe. A 550 bp amplicon internal to the 16S rRNA gene of C. helveticus was used to determine restriction fragment length polymorphisms (RFLPs) in genomic Southern blots, confirming that the copy number of the C. helveticus gene was three, and identifying nine 16S rRNA gene profiles. In 5/12 C. helveticus isolates identified by PCR, an enlarged amplicon was detected. The enlarged 16S rRNA gene of one of these strains, NCTC 12838, was sequenced and shown to contain an atypical intervening sequence (IVS) of 148 nucleotides. The position and size of such an IVS was inferred in the other four isolates by PCR with primers 5' and 3' to its position in NCTC 12838. This is a first report of an IVS in the 16S rRNA gene of a eubacterium.

Molecular typing of Helicobacter pylori isolates from asymptomatic, ulcer and gastritis patients by urease gene polymorphism

The gastric-adapted bacterium Helicobacter pylori plays an important role in gastritis and ulcer disease, but no phenotypic typing scheme presently exists for this organism. With a view to the development of genotypic typing, we have compared isolates of H. pylori from gastritis or ulcer patients with those from subjects exhibiting no disease. Variation was analysed at the urease genes, ureA and ureCD, by employing PCR-generated probes in genomic Southern blot hybridizations. Whilst ureA restriction fragments provided a fourfold subgrouping of strains, ureCD fragments were considerably more discriminatory. Twenty-four combined ureACD profiles were generated with Hind III, subdividing the 64 strains into 11 types and 13 single profiles. The most prevalent profile (UI) was found in 33% of strains, almost all from gastritis or ulcer patients. On the other hand strains isolated from asymptomatic individuals had the most diverse ureACD profiles. A key finding from this set of isolates was that strains of H. pylori associated with general gastroduodenal disease were genetically more homogeneous than strains carried by people without disease symptoms.

Genetic diversity of Helicobacter pylori indexed with respect to clinical symptomatology, using a 16S rRNA and a species-specific DNA probe

DNA probes are described which identify group and fingerprint strains of the human gastric pathogen Helicobacter pylori, on the basis of well-defined band homologies. A 544 bp internal fragment of the 16S ribosomal RNA gene was generated by polymerase chain reaction (PCR) with primers derived from the Escherichia coli rRNA gene sequence. In genomic Southern blots this probe detected restriction site variation around these loci, generating simple but strain-specific molecular fingerprints. A small conserved chromosomal fragment of 1.2 kbp, Hps, species-specific for H. pylori, was obtained by cloning random HindIII fragments into pUC19. It was useful for dot-blot identification, and also separated isolates into one major and two minor groups. When results for these two probes were combined, a baseline characterization of genotype was obtained. A band-matching database of molecular fingerprints for the type strain and 63 clinical isolates of H. pylori from asymptomatic, ulcer and gastritis contexts is presented. No significant association between the genotypes at this level of definition and the associated clinical symptomatology of the isolates was detected.

Helicobacter canis sp. nov., a new species from dogs: an integrated study of phenotype and genotype

A group of Campylobacter-like organisms (CLOs) were isolated from the faeces of diarrhoeic or healthy dogs, constituting 4% of all CLOs from this source. Since they formed a unique DNA homology group within the genus Helicobacter, and exhibited distinctive phenotypic properties, they were collectively termed the HC group. A polyphasic taxonomic analysis was made of this group. The phenotype of four dog isolates and a single human isolate was unique and could be distinguished bacteriologically from other helicobacters. Electron microscopic ultrastructure revealed defining characteristics of Helicobacter. The 16S rRNA gene of the nominated type strain NCTC 12739T was sequenced, and its analysis delineated the group as a new species of Helicobacter. This conclusion was supported by relative DNA homology and whole-cell protein electrophoretic patterns. We therefore propose the name Helicobacter canis sp. nov. for this group. The species most closely related to H. canis sp. nov. were H. cinaedi, 'Flexispira rappini' and H. fennelliae. A species-specific recombinant DNA probe was cloned from NCTC 12739T for use in routine laboratory identification and epidemiological studies. The faecal source, bile tolerance and lack of urease activity of H. canis sp. nov. suggest that this new Helicobacter species colonizes the lower bowel rather than the stomach.

Biotype and molecular fingerprints of metronidazole-resistant strains of Helicobacter pylori from antral gastric mucosa

Biotypes, ribosomal RNA gene restriction patterns (ribopatterns), whole-cell protein patterns and plasmid profiles of paired Helicobacter pylori isolates from 17 patients were examined. Each pair comprised a pre- and a post-treatment isolate; nine of the 17 post-treatment isolates were obtained after treatment with tripotassium dicitrate bismuthate (De-Nol) and metronidazole. All strains of H. pylori had identical biotypes, but exhibited diversity between pairs in their molecular fingerprints. Each of the 17 strain pairs had unique ribopatterns; the pre- and post-treatment isolates in most pairs (16 of 17) were similar or identical, irrespective of metronidazole susceptibility. DNA subtype variants were detected in three patient sets. Although nine post-treatment isolates had acquired resistance to metronidazole, most (six of nine) resembled the pre-treatment isolates in their ribopattern, protein and plasmid profiles. No significant correlation was observed between metronidazole resistance and plasmid content in these H. pylori isolates. Emergence of post-treatment metronidazole-resistant isolates of H. pylori was associated only rarely with colonisation by a novel strain or acquisition of a plasmid and, in most patients, probably resulted from spontaneous emergence of resistance in the original infecting strain.

16S rrn gene copy number in Helicobacter pylori and its application to molecular typing

The copy number of the genes encoding 16S ribosomal RNA was analysed for the genomes of geographically diverse strains of Helicobacter pylori, and restriction site variation within and around the genes was characterized. A DNA probe of 550 bp was amplified by the polymerase chain reaction from genomic DNA of the type strain NCTC 11637. This probe constituted a sequence internal to the 3' end of the 16S rrn gene. Homology profiles were compared for genomic Southern blots made with four restriction enzymes cutting within and outside the probe sequence. A copy number of two was established for all 12 strains analysed. This approach yielded significantly simpler data than does conventional 'ribotyping ' of H. pylori. It was equally discriminatory, however, and provided strain-specific 16S rrn gene 'signatures'. These represent both fundamental physical-genetic information and a novel approach to typing this gastric pathogen.

Campylobacter helveticus sp. nov., a new thermophilic species from domestic animals: characterization, and cloning of a species-specific DNA probe

An atypical group of thermophilic catalase-negative Campylobacter strains, the 'CH' (Swiss) group, can be recovered from faeces of domestic cats and dogs after selection by filtration, or with the antibiotic cefoperazone. This group of strains shows no relative DNA homology with any species in rRNA superfamily VI (Vandamme et al., 1991, International Journal of Systematic Bacteriology 41, 88-103) except with four thermophilic Campylobacter species, notably C. upsaliensis. The group is homogeneous and possesses a DNA base composition, cellular morphology at the electron microscope level and phenotypic properties characteristic of Campylobacter. Nonetheless it is distinct from known species of Campylobacter in terms of conventional bacteriological tests, total cellular protein profile, rRNA gene profile, and genomic DNA homology. On the basis of an integrated study of phenotype and genotype, we conclude that these bacteria constitute a previously undescribed species for which we propose the name Campylobacter helveticus sp. nov. A species-specific recombinant DNA probe was cloned from the designated type strain (NCTC 12470) for use in identification and further analysis of the epidemiology, pathogenicity and transmission of C. helveticus.

Ribosomal RNA gene restriction patterns of Helicobacter pylori: analysis and appraisal of Hae III digests as a molecular typing system

Ribosomal RNA gene restriction patterns (ribopatterns) of 162 strains of Helicobacter pylori from 93 patients were studied to assess their suitability for use as the basis of a molecular typing system. Computer-assisted numerical analysis of Hae III ribopatterns of 122 strains from 9 countries in 4 continents showed that almost every strain had a distinct and unique ribopattern and only strains from the same individual were genomically matched in all bands or with minor (1-2 band) differences. Hae III ribopatterns offered high typability and reproducibility but were too discriminatory for large-scale epidemiological typing purposes because no rational basis for grouping strains was evident. In contrast, composite band profiles based on 21 band loci within the Hae III ribopatterns, which were used to compare strain sets selected on toxigenicity and geographical origin, were more conserved. Minor differences between some strain sets in several band loci were detected but generally the composite profiles were a reproducible feature of H. pylori. We conclude that Hae III ribopatterns provide an excellent fingerprint for small-scale studies of genomic variation in defined populations, such as sequential patient isolates, but are too specific for general typing of H. pylori.