Cognitive function and risks of cardiovascular disease and hypoglycaemia in patients with type 2 diabetes: the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial

AIMS/HYPOTHESIS

The relationship between cognitive function, cardiovascular disease and premature death is not well established in patients with type 2 diabetes. We assessed the effects of cognitive function in 11,140 patients with type 2 diabetes who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. Furthermore, we tested whether level of cognitive function altered the beneficial effects of the BP-lowering and glycaemic-control regimens in the trial.

METHODS

Cognitive function was assessed using the Mini Mental State Examination at baseline, and defined by scores 28-30 ('normal', n = 8,689), 24-27 ('mild dysfunction', n = 2,231) and <24 ('severe dysfunction', n = 212). Risks of major cardiovascular events, death and hypoglycaemia and interactions with treatment were assessed using Cox proportional hazards analysis.

RESULTS

Relative to normal function, both mild and severe cognitive dysfunction significantly increased the multiple-adjusted risks of major cardiovascular events (HR 1.27, 95% CI 1.11-1.46 and 1.42, 95% CI 1.01-1.99; both p < 0.05), cardiovascular death (1.41, 95% CI 1.16-1.71 and 1.56, 95% CI 0.99-2.46; both p <or= 0.05) and all-cause death (1.33, 95% CI 1.16-1.54 and 1.50, 95% CI 1.06-2.12; both p < 0.03). Severe, but not mild, cognitive dysfunction increased the risk of severe hypoglycaemia (HR 2.10, 95% CI 1.14-3.87; p = 0.018). There was no evidence of heterogeneity of treatment effects on cardiovascular outcomes in subgroups defined by cognitive function at baseline.

CONCLUSIONS/INTERPRETATION

Cognitive dysfunction is an independent predictor of clinical outcomes in patients with type 2 diabetes, but does not modify the effects of BP lowering or glucose control on the risks of major cardiovascular events.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00145925.

Tools for interpreting large-scale protein profiling in microbiology

Quantitative proteomic analysis of microbial systems generates large datasets that can be difficult and time-consuming to interpret. Fortunately, many of the data display and gene-clustering tools developed to analyze large transcriptome microarray datasets are also applicable to proteomes. Plots of abundance ratio vs. total signal or spectral counts can highlight regions of random error and putative change. Displaying data in the physical order of the genes in the genome sequence can highlight potential operons. At a basic level of transcriptional organization, identifying operons can give insights into regulatory pathways as well as provide corroborating evidence for proteomic results. Classification and clustering algorithms can group proteins together by their abundance changes under different conditions, helping to identify interesting expression patterns, but often work poorly with noisy data such as typically generated in a large-scale proteomic analysis. Biological interpretation can be aided more directly by overlaying differential protein abundance data onto metabolic pathways, indicating pathways with altered activities. More broadly, ontology tools detect altered levels of protein abundance for different metabolic pathways, molecular functions, and cellular localizations. In practice, pathway analysis and ontology are limited by the level of database curation associated with the organism of interest.

Ethnic disparities in incidence of stroke subtypes: Auckland Regional Community Stroke Study, 2002–2003

BACKGROUND

Limited population-based data exist on differences in the incidence of major pathological stroke types and ischaemic stroke subtypes across ethnic groups. We aimed to provide such data within the large multi-ethnic population of Auckland, New Zealand.

METHODS

All first-ever cases of stroke (n=1423) in a population-based register in 940 000 residents (aged 15 years) in Auckland, New Zealand, for a 12-month period in 2002-2003, were classified into ischaemic stroke, primary intracerebral haemorrhage (PICH), subarachnoid haemorrhage, and undetermined stroke, according to standard definitions and results of neuroimaging/necropsy (in over 90% of cases). Ischaemic stroke was further classified into five subtypes. Ethnicity was self-identified and grouped as New Zealand (NZ)/European, Maori/Pacific, and Asian/other. Incidence rates were standardised to the WHO world population by the direct method, and differences in rates between ethnic groups expressed as rate ratios (RRs), with NZ/European as the reference group.

FINDINGS

In NZ/European people, ischaemic stroke comprised 73%, PICH 11%, and subarachnoid haemorrhage 6%, but PICH was higher in Maori/Pacific people (17%) and in Asian/other people (22%). Compared with NZ/European people, age-adjusted RRs for PICH were 2.7 (95% CI 1.8-4.0) and 2.3 (95% CI 1.4-3.7) among Maori/Pacific and Asian/other people, respectively. The corresponding RR for ischaemic stroke was greater for Maori/Pacific people (1.7 [95% CI 1.4-2.0]), particularly embolic stroke, and for Asian/other people (1.3 [95% CI 1.0-1.7]). The onset of stroke in Maori/Pacific and Asian/other people began at significantly younger ages (62 years and 64 years, respectively) than in NZ/Europeans (75 years; p<0.0001). There were ethnic differences in the risk factor profiles (such as age, sex, hypertension, cardiac disease, diabetes, hypercholesterolaemia, smoking status, overweight) for the stroke types and subtypes.

INTERPRETATION

Compared to NZ/Europeans, Maori/Pacific and Asian/other people are at higher risk of ischaemic stroke and PICH, whereas similar rates of subarachnoid haemorrhage were evident across ethnic groups. The ethnic disparities in the rates of stroke types could be due to substantial differences found in risk factor profiles between ethnic groups. This information should be considered when planning prevention and stroke-care services in multi-ethnic communities.

Obesity and health-related quality of life: results from a weight loss trial

AIMS

To measure health-related quality of life (HRQoL) in overweight and obese New Zealand adults taking part in a weight loss trial, and to compare findings with the New Zealand population.

METHODS

Individuals (aged over 18 years with a BMI of 28-50 kg/m2) participated in a randomised controlled weight loss trial. HRQoL was measured using the SF-36 questionnaire.

RESULTS

The 250 study participants had a mean (SD) age of 48 (12) years and a mean BMI of 35.4 (5.3) kg/m2. Mean physical component (PCS) and mental component summary scores (MCS) were 47.2 (9.0) and 46.9 (11.1) respectively. Participants in the highest BMI tertile (>37 kg/m2) reported significantly lower PCS scores compared with those in the middle and lowest tertiles (p=0.01), but no significant differences were seen in MCS scores (p=0.65). Comparison with population norms revealed significantly lower mean scores in all 8 SF-36 domains except mental health. No significant effect of modest weight loss on HRQoL was seen.

CONCLUSIONS

These overweight and obese New Zealand adults experienced significantly impaired HRQoL compared to the New Zealand population. Small reductions in weight had no significant impact on HRQoL in this substantially overweight population.

Complete genome sequence of the genetically tractable hydrogenotrophic methanogen Methanococcus maripaludis

The genome sequence of the genetically tractable, mesophilic, hydrogenotrophic methanogen Methanococcus maripaludis contains 1,722 protein-coding genes in a single circular chromosome of 1,661,137 bp. Of the protein-coding genes (open reading frames [ORFs]), 44% were assigned a function, 48% were conserved but had unknown or uncertain functions, and 7.5% (129 ORFs) were unique to M. maripaludis. Of the unique ORFs, 27 were confirmed to encode proteins by the mass spectrometric identification of unique peptides. Genes for most known functions and pathways were identified. For example, a full complement of hydrogenases and methanogenesis enzymes was identified, including eight selenocysteine-containing proteins, with each being paralogous to a cysteine-containing counterpart. At least 59 proteins were predicted to contain iron-sulfur centers, including ferredoxins, polyferredoxins, and subunits of enzymes with various redox functions. Unusual features included the absence of a Cdc6 homolog, implying a variation in replication initiation, and the presence of a bacterial-like RNase HI as well as an RNase HII typical of the Archaea. The presence of alanine dehydrogenase and alanine racemase, which are uniquely present among the Archaea, explained the ability of the organism to use L- and D-alanine as nitrogen sources. Features that contrasted with the related organism Methanocaldococcus jannaschii included the absence of inteins, even though close homologs of most intein-containing proteins were encoded. Although two-thirds of the ORFs had their highest Blastp hits in Methanocaldococcus jannaschii, lateral gene transfer or gene loss has apparently resulted in genes, which are often clustered, with top Blastp hits in more distantly related groups.

Leg ulceration and perceived health: a population based case-control study

OBJECTIVES

To quantify the effect of leg ulceration on health-related quality of life and to estimate a health state value for leg ulceration.

DESIGN

Population based case-control study.

SETTING

Two New Zealand health districts (population 540,468 people).

SUBJECTS

241 people with a leg ulcer of any aetiology, and 224 controls randomly selected from the electoral roll using stratified sampling.

MAIN OUTCOME MEASURES

health-related quality of life as measured by the eight domains of the Short Form 36 question Health Survey, adjusted for age, sex and confounding co-morbidities; the physical component summary and mental component summary scores of the Short Form 36 question Health Survey standardised for age and sex; preference-based health state value derived from the Short Form 36 question Health Survey.

RESULTS

Completed Short Form 36 question Health Survey questionnaires were available for 230 cases (95%) and 218 controls (97%). Cases reported significantly lower mean scores than controls across all eight domains of the Short Form 36 question Health Survey (P < 0.0005). Mean domain scores for cases were also significantly lower than population norms. The mean physical component summary score for cases and controls was 45.2 versus 50.1 (P < 0.0001) and the mean mental component summary score was 48.1 for cases versus 51 for controls (P < 0.0001). The mean health state values (adjusted for age and sex) were 0.80 for cases and 0.89 for controls.

CONCLUSION

Leg ulcers reduce quality of life to a similar extent as other common chronic conditions, such as arthritis and diabetes.

Related IgA1 and IgG producing cells in blood and diseased mucosa in ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease in which the colonic mucosa is infiltrated with plasma cells producing IgG autoantibodies. It is not known whether this represents a local mucosal response which has switched to IgG or a peripheral response which may have been initiated by peripheral antigen which homed to the colonic mucosa. The clonal distribution of IgG secreting cells and isotype switched variants in UC is not known.

AIMS

To investigate the clonal distribution of mucosal IgG in UC and to search for related IgG and IgA secreting cells in normal and diseased mucosa and blood in UC. To investigate characteristics which may discriminate between the mucosal and peripheral repertoire in the normal mucosa and in UC.

PATIENTS

Blood and normal and diseased mucosa from two patients with UC were studied.

METHODS

Immunoglobulin gene analysis and clone specific polymerase chain reaction were used to study the clonal distribution and characteristics of IgG and related IgA in the mucosa and blood of patients with UC.

RESULTS

The IgG response in the mucosa of UC patients included widespread clones of cells that were present in both the diseased mucosa and blood but that were scarce in normal mucosa. Clonally related IgA class switch variants, all IgA1, were detected but also only in the diseased mucosa and blood. This suggests that these clones home preferentially to the diseased mucosa. We showed that J(H)1 usage was characteristic of the peripheral repertoire, and that examples of J(H)1 usage were observed in mucosal IgG in UC.

CONCLUSIONS

Overall, these data are consistent with a model of UC in which a peripheral response is expressed and expanded in the colonic mucosa.

Mass spectrometric analysis of recombinant adenylate cyclase toxin from Bordetella pertussis strain 18323/pHSP9

The adenylate cyclase toxin-hemolysin (ACT) is a key virulence factor of the whooping cough agent Bordetella pertussis (Bp). The major cytotoxic activity of this 1706-residue protein consists of its capacity to invade a variety of eukaryotic cells directly across their cytoplasmic membrane and to deliver into cells a catalytic adenylate cyclase domain. This causes impairment of immune effector cells and apoptosis of lung macrophages by uncontrolled conversion of ATP to cAMP. The adenylate cyclase toxin-hemolysin acquires biological activity upon post-translational amide-linked palmitoylation of the epsilon-amino group of lysine 983 (K983) by the accessory fatty acyltransferase, CyaC. However, an additional conserved acylation site can be identified in ACT at lysine 860 (K860) and this residue is palmitoylated when recombinant ACT is produced in Escherichia coli (r-Ec-ACT). In this paper we report the double acylation of r-Bp-ACT secreted by a recombinant Bp strain 18323/pHSP9. This strain overproduces ACT from an oligocopy plasmid carrying the entire cya locus of Bordetella pertussis 18323. Palmitoylation of both conserved lysines (K860 and K983) of r-Bp-ACT expressed by this Bp strain was found. In addition, an error in the deduced protein sequence was identified, with Leu being the real residue at position 1001 and not the Val residue given in the published gene sequence. We also discuss these results in comparison with those from recombinant ACT expressed in E. coli strain K12 XL1-Blue. The analytical approach for characterization of the fatty acylation of ACT from strain 18323/pHSP9 consisted of multiple proteolytic digestion procedures (trypsin, Asp-N), microcapillary liquid chromatography/tandem mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Acylation of lysine 983 is sufficient for toxin activity of Bordetella pertussis adenylate cyclase. Substitutions of alanine 140 modulate acylation site selectivity of the toxin acyltransferase CyaC

The capacity of adenylate cyclase toxin (ACT) to penetrate into target cells depends on post-translational fatty-acylation by the acyltransferase CyaC, which can palmitoylate the conserved lysines 983 and 860 of ACT. Here, the in vivo acylating capacity of a set of mutated CyaC acyltransferases was characterized by two-dimensional gel electrophoresis and mass spectrometric analyses of the ACT product. Substitutions of the potentially catalytic serine 20 and histidine 33 residues ablated acylating activity of CyaC. Conservative replacements of alanine 140 by glycine (A140G) and valine (A140V) residues, however, affected selectivity of CyaC for the two acylation sites on ACT. Activation by the A140G variant of CyaC generated a mixture of bi- and monoacylated ACT molecules, modified either at both Lys-860 and Lys-983, or only at Lys-860, respectively. In contrast, the A140V CyaC produced a nearly 1:1 mixture of nonacylated pro-ACT with ACT monoacylated almost exclusively at Lys-983. The respective proportion of toxin molecules acylated at Lys-983 correlated well with the cell-invasive activity of both ACT mixtures, which was about half of that of ACT fully acylated on Lys-983 by intact CyaC. These results show that acylation of Lys-860 alone does not confer cell-invasive activity on ACT, whereas acylation of Lys-983 is necessary and sufficient.

Searching the Porphyromonas gingivalis genome with peptide fragmentation mass spectra

An approach is described for genomic database searching based on experimentally observed proteolytic fragments, e.g., isolated from 1D or 2D gels or analyzed directly, that can be applied to unfinished prokaryotic genomic data in the absence of annotations or previously assigned open reading frames (ORFs). This variation on the database search is in contrast to the more familiar use of peptide mass spectral fragmentation data to search fully annotated inferred protein databases, e.g., OWL or SWISS-PROT. We compared the SEQUEST search results from a six reading frame translation of the Porphyromonas gingivalis genome DNA sequence with those from computationally derived ORFs created using publicly available genomics software tools. The ORF approach eliminated many of the artifacts present in output from the six reading frame search. The method was applied to uninterpreted tandem mass spectrometric data derived from proteins secreted by the periodontal pathogen Porphyromonas gingivalis in response to the gingival epithelial cell environment, a model system for the study of host-pathogen interactions relevant to human periodontal disease.

Escherichia coli alpha-hemolysin (HlyA) is heterogeneously acylated in vivo with 14-, 15-, and 17-carbon fatty acids

alpha-Hemolysin (HlyA) is a secreted protein virulence factor observed in certain uropathogenic strains of Escherichia coli. The active, mature form of HlyA is produced by posttranslational modification of the protoxin that is mediated by acyl carrier protein and an acyltransferase, HlyC. We have now shown using mass spectrometry that these modifications, when observed in protein isolated in vivo, consist of acylation at the epsilon-amino groups of two internal lysine residues, at positions 564 and 690, with saturated 14- (68%), 15- (26%), and 17- (6%) carbon amide-linked side chains. Thus, HlyA activated in vivo consists of a heterogeneous family of up to nine different covalent structures, and the substrate specificity of the HlyC acyltransferase appears to differ from that of the closely related CyaC acyltransferase expressed by Bordetella pertussis.

A PhoP-regulated outer membrane protease of Salmonella enterica serovar typhimurium promotes resistance to alpha-helical antimicrobial peptides

The outer membrane protein contents of Salmonella enterica serovar Typhimurium strains with PhoP/PhoQ regulon mutations were compared by two-dimensional gel electrophoresis. At least 26 species of outer membrane proteins (OMPs) were identified as being regulated by PhoP/PhoQ activation. One PhoP/PhoQ-activated OMP was identified by semiautomated tandem mass spectrometry coupled with electronic database searching as PgtE, a member of the Escherichia coli OmpT and Yersinia pestis Pla family of outer membrane proteases. Salmonella PgtE expression promoted resistance to alpha-helical cationic antimicrobial peptides (alpha-CAMPs). Strains expressing PgtE cleaved C18G, an 18-residue alpha-CAMP present in culture medium, indicating that protease activity is likely to be the mechanism of OmpT-mediated resistance to alpha-CAMPs. PhoP/PhoQ did not regulate the transcription or export of PgtE, indicating that another PhoP/PhoQ-dependent mechanism is required for PgtE outer membrane localization. PgtE is a posttranscriptionally regulated component of the PhoP/PhoQ regulon that contributes to Salmonella resistance to innate immunity.

A remote flow cell for UV absorbance detection with capillary HPLC based on a single strand fiber optic

A remote flow cell based on a single strand of fused-silica fiber optic was built for UV absorbance detection with a packed capillary HPLC system, using commercially available pumps, detection electronics (Shimadzu) and fittings. This 'off-column' flow cell design is applicable to both pressure and electro-osmotically driven systems. The goals were to minimize the linearity and light leakage problems that often limit the performance of UV absorbance detection with capillary chromatography. A linear dynamic range of 10(3) (reserpine, lambda = 220 nm), and a concentration detection limit of 5.1 x 10(-8) mol l-1 were observed. Baseline noise was measured at 3.5 x 10(-5) absorbance units (AU), with a standard deviation of 1.7 x 10(-5) AU. The illuminated volume of approximately 3 nl was optimized for capillaries with inner diameters in the range 50-100 microns, and flow rates from 100 nl min-1 to 1 microliter min-1. These modifications of readily available instrumentation have allowed the construction of a practical system for fractionating complex mixtures of peptides in small amounts, prior to mass spectrometry or additional wet chemistry steps.

Rapid isolation method for lipopolysaccharide and lipid A from gram-negative bacteria

A fast, convenient extraction method for lipopolysaccharide (LPS), using a commercial RNA isolating reagent, allows the isolation of LPS or lipid A from low milligram (dry weight) quantities of bacterial cells. The method avoids the use of specialized equipment and has been used for processing relatively large numbers of samples. The major components of the commercial RNA isolating reagent, Tri-Reagent, are phenol and guanidinium thiocyanate in aqueous solution. The bacterial cell membranes are disrupted with guanidinium thiocyanate, which eliminates the need for mechanical cell disruption (e.g. French press) or heating. LPS and its degradation products, with particular attention paid to its bioactive lipid A portion, were measured and compared with those from the most common conventional extraction method, hot phenol-water. Negative ion quadrupole ion trap and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, fatty acid composition analysis by capillary gas chromatography, total and free phosphate by UV spectrophotometry and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed that LPS and lipid A isolated using the Tri-Reagent approach were cleaner and suffered less degradation through loss of phosphate and (or) fatty acyl side chains from lipid A. The Tri-Reagent extraction method generated low free phosphate contamination, 11% of the total phosphate concentration, whereas the hot phenol-water extraction method gave approximately 58% as free, inorganic phosphate. Similar results were observed for the degradation of fatty acyl side chains. The time required by the new method is considerably shorter (two or three days) than that required by conventional hot phenol-water extraction (about two weeks).

Characteristics of human IgA and IgM genes used by plasma cells in the salivary gland resemble those used in duodenum but not those used in the spleen

Immunologically, the parotid salivary gland is an effector site that secretes large quantities of polyspecific Abs into the saliva, mainly of the IgA isotype. It is considered to be part of the common mucosal immune system but the inductive site for the Ab-producing cells of the salivary gland has not yet been clearly identified. The origin and diversity of cells of B lineage can be investigated by analyzing their Ig heavy chain genes (IgH). We have obtained sequences of IgM and IgA VH4-34 genes from plasma cells in human salivary gland, duodenal lamina propria, and splenic red pulp. Related sequences were found in different areas sampled within each tissue studied, indicating that the plasma cells carrying these genes are widespread with limited diversity. Examples of related IgH genes that are isotype switched were also seen in the salivary gland. The genes from plasma cells of the salivary gland were highly mutated, as were duodenal plasma cell sequences. The level of mutation was significantly higher than that seen in splenic plasma cell sequences. Analysis of CDR3 regions showed that the sequences from salivary gland had significantly smaller CDR3 regions than sequences from spleen, due to differences in number and type of DH regions used. Sequences from duodenum also had smaller CDR3 regions. Therefore, plasma cells from human duodenum and salivary gland showed characteristics that differed from those of human splenic plasma cells.

Association of dialyzer reuse and hospitalization rates among hemodialysis patients in the US

OBJECTIVES

To determine if reuse of hemodialyzers is associated with higher rates of hospitalization and their resulting costs among end-stage renal disease (ESRD) patients.

METHODS

Noncurrent cohort study of hospitalization rates among 27,264 ESRD patients beginning hemodialysis in the United States in 1986 and 1987.

RESULTS

Dialysis in free-standing facilities reprocessing dialyzers was associated with a greater rate of hospitalization than in facilities not reprocessing (relative rate (RR) = 1.08, 95% confidence interval (CI), 1.02-1.14). This higher rate of hospitalization was observed with dialyzer reuse using peracetic/acetic acids (RR = 1.11, CI 1. 04-1.18) and formaldehyde (RR = 1.07, CI 1.00-1.14), but not glutaraldehyde (p = 0.97). There was no difference among hospitalization rates in hospital-based facilities reprocessing dialyzers with any sterilant and those not reprocessing. Hospitalization for causes other than vascular access morbidity in free-standing facilities reusing dialyzers with formaldehyde was not different from hospitalization in facilities not reusing. However, reuse with peracetic/acetic acids was associated with higher rates of hospitalization than formaldehyde (RR = 1.08, CI 1.03-1.15).

CONCLUSIONS

Dialysis in free-standing facilities reprocessing dialyzers with peracetic/acetic acids or formaldehyde was associated with greater hospitalization than dialysis without dialyzer reprocessing. This greater hospitalization accounts for a large increment in inpatient stays in the USA. These findings raise important concerns about potentially avoidable morbidity among hemodialysis patients.

Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa

Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease.

Clinical governance: culture, leadership and power--the key to changing attitudes and behaviours in trusts

Clinical governance places for legal duty for quality on Trust chief executives. The article deals with how chief executives can overcome the cultural and behavioural obstacles to change which impede the journey to developing effective structures for clinical governance. To establish effective structures for clinical governance, chief executives will need to address these features of organisational life--culture, power and leadership. The article seeks to provide practical ways in which they can do this.

Helicobacter pylori treatment and antibiotic susceptibility: results of a five-year audit

BACKGROUND

Helicobacter pylori eradication treatment has been a rapidly evolving field. Audit of treatment results provides reassurance that trial data can be translated into routine clinical practice.

METHODS

Data were collected prospectively over five years. Patients were given four different treatment regimens over the audit period 'standard' triple therapy, two types of clarithromycin-based treatment or ranitidine, amoxycillin and metronidazole. Eradication was proven by a urea breath test at least four weeks after completing treatment.

RESULTS

Eradication treatment for H. pylori was given to 665 patients; 89% had follow-up data. H. pylori eradication was significantly associated with treatment type (p<0.0001) and smoking (p=0.04) by univariate analysis, but was not associated with sex, age, alcohol consumption, endoscopic diagnosis, recent treatment with anti-secretory drugs or NSAIDs. By logistic regression analysis, only treatment type was significant (p=0.0001). H. pylori culture and sensitivities were available for 255 patients. Metronidazole resistance was shown for 84 isolates (32%) and clarithromycin resistance for 18 isolates (6.8%). Metronidazole resistance was significantly associated with younger age (p=0.02), ethnicity (p=0.02), female sex (p=0.02), and year of endoscopy (p=0.04), but was not associated with clarithromycin resistance. Clarithromycin resistance was not associated with age, sex, or ethnicity. Metronidazole resistance significantly affected H. pylori eradication for regimens containing metronidazole without clarithromycin. Eradication with metronidazole without clarithromycin was achieved in 90% of sensitive strains but only 55% of resistant strains (p<0.001). Metronidazole resistance was not significantly associated with treatment failure when metronidazole was combined with clarithromycin. Eradication with metronidazole and clarithromycin was achieved in 86% of sensitive strains and 78% of resistant strains (p=0.42).

CONCLUSION

Treatment type and antibiotic susceptibility are the most important determinants of treatment success.