Accessory genetic content in Campylobacter jejuni ST21CC isolates from feces and blood.

Campylobacter jejuni is an important foodborne pathogen and the most commonly reported bacterial cause of gastroenteritis. C. jejuni is occasionally found in blood, although mechanisms important for invasiveness have remained unclear. C. jejuni is divided into many different lineages, of which the ST21 clonal complex (CC) is widely distributed. Here, we performed comparative genomic and in vitro analyses on 17C. jejuni ST21CC strains derived from human blood and feces in order to identify features associated with isolation site. The ST21CC lineage is divided into two large groups; centered around ST-21 and ST-50. Our clinical strains, typed as ST-50, showed further microevolution into two distinct clusters. These clusters were distinguished by major differences in their capsule loci and the distribution of accessory genetic content, including C. jejuni integrated elements (CJIEs) and plasmids. Accessory genetic content was more common among fecal than blood strains, whereas blood strains contained a hybrid capsule locus which partially consisted of C. jejuni subsp. doylei-like content. In vitro infection assays with human colon cell lines did not show significant differences in adherence and invasion between the blood and fecal strains. Our results showed that CJIEs and plasmid derived genetic material were less common among blood isolates than fecal isolates; in contrast, hybrid capsule loci, especially those containing C. jejuni subsp. doylei-like gene content, were found among many isolates derived from blood. The role of these findings requires more detailed investigation.

Risk factors associated with Campylobacter detected by PCR in humans and animals in rural Cambodia.

Campylobacter are worldwide-occurring zoonotic bacteria, with the species Campylobacter jejuni and C. coli commonly associated with diarrhoea in children in low-income countries. In this cross-sectional study, the prevalence of C. jejuni and C. coli in human and livestock faecal samples was detected by PCR and zoonotic risk factors associated with human Campylobacter positivity were identified. In total 681 humans and 753 livestock (chickens, ducks, pigs, cattle) from 269 households were sampled. Children aged <16 years were more frequently Campylobacter positive (19%) than adults (8%) and multilevel logistic models revealed that human C. jejuni positivity was associated with the following household practices: home-slaughtering [odds ratio (OR) 2·4, P = 0·01], allowing animals access to sleeping and food preparation areas (OR 2·8, P = 0·02), and eating undercooked meat (OR 6·6, P = 0·05), while frequent consumption of beef was protective (OR 0·9, P = 0·05). Associations were stronger for home-slaughtering (OR 4·9, P = 0·004) with C. jejuni infection in children only. Campylobacter was highly prevalent in pigs (72%) and chickens (56%) and risk factors associated with human Campylobacter positivity were identified throughout the meat production chain. The findings underline the importance of studying source attributions throughout the production chain and the need for upgraded understanding of Campylobacter epidemiology in low-income countries.

Composition of human faecal microbiota in resistance to Campylobacter infection.

In mice, specific species composition of gut microbiota enhances susceptibility to Campylobacter jejuni but little is known about the specific composition of the human gut microbiota in providing protection from infections caused by enteropathogens. Healthy adult individuals, who travelled in groups from Sweden to destinations with an estimated high risk for acquisition of Campylobacter infection, were enrolled. Faecal samples, collected before travelling and after returning home, were cultured for bacterial enteropathogens, and analysed for Campylobacter by PCR and for the species composition of the microbiota by 16S amplicon massive parallel sequencing. The microbiota compositions were compared between persons who became infected during their travel and those who did not. A total of 63 participants completed the study; 14 became infected with Campylobacter, two with Salmonella and 47 remained negative for the enteropathogens tested. After exclusion of samples taken after antimicrobial treatment, 49 individuals were included in the final analyses. Intra-individual stability of the microbiota was demonstrated for samples taken before travelling. The original diversity of the faecal microbiota was significantly lower among individuals who later became infected compared with those who remained uninfected. The relative abundances of bacteria belonging to the family Lachnospiraceae, and more specifically its two genera Dorea and Coprococcus, were significantly higher among those who remained uninfected. The travel-related infection did not significantly modify the faecal microbiota composition. Species composition of human gut microbiota is important for colonization resistance to Campylobacter infection. Especially individuals with a lower diversity are more susceptible to Campylobacter infection.

Campylobacteriosis: the role of poultry meat.

The incidence of human infections caused by Campylobacter jejuni and Campylobacter coli, the main bacterial agents of gastrointestinal disease, has been increasing worldwide. Here, we review the role of poultry as a source and reservoir for Campylobacter. Contamination and subsequent colonization of broiler flocks at the farm level often lead to transmission of Campylobacter along the poultry production chain and contamination of poultry meat at retail. Yet Campylobacter prevalence in poultry, as well as the contamination level of poultry products, vary greatly between different countries so there are differences in the intervention strategies that need to be applied. Temporal patterns in poultry do not always coincide with those found in human infections. Studies in rural and urban areas have revealed differences in Campylobacter infections attributed to poultry, as poultry seems to be the predominant reservoir in urban, but not necessarily in rural, settings. Furthermore, foreign travel is considered a major risk factor in acquiring the disease, especially for individuals living in the northern European countries. Intervention strategies aimed at reducing Campylobacter colonization in poultry and focused at the farm level have been successful in reducing the number of Campylobacter cases in several countries. Increasing farm biosecurity and education of consumers are likely to limit the risk of infection. Overall, poultry is an important reservoir and source of human campylobacteriosis, although the contribution of other sources, reservoirs and transmission warrants more research.

Comparative genomics and genome biology of invasive Campylobacter jejuni.

Campylobacter jejuni is a major pathogen in bacterial gastroenteritis worldwide and can cause bacteremia in severe cases. C. jejuni is highly structured into clonal lineages of which the ST677CC lineage has been overrepresented among C. jejuni isolates derived from blood. In this study, we characterized the genomes of 31 C. jejuni blood isolates and 24 faecal isolates belonging to ST677CC in order to study the genome biology related to C. jejuni invasiveness. We combined the genome analyses with phenotypical evidence on serum resistance which was associated with phase variation of wcbK; a GDP-mannose 4,6-dehydratase involved in capsular biosynthesis. We also describe the finding of a Type III restriction-modification system unique to the ST-794 sublineage. However, features previously considered to be related to pathogenesis of C. jejuni were either absent or disrupted among our strains. Our results refine the role of capsule features associated with invasive disease and accentuate the possibility of methylation and restriction enzymes in the potential of C. jejuni to establish invasive infections. Our findings underline the importance of studying clinically relevant well-characterized bacterial strains in order to understand pathogenesis mechanisms important in human infections.

Lipooligosaccharide locus class of Campylobacter jejuni: sialylation is not needed for invasive infection.

Campylobacter jejuni is a highly diverse enteropathogen that is commonly detected worldwide. It can sometimes cause bacteraemia, but the bacterial characteristics facilitating bloodstream infection are not known. A total of 73 C. jejuni isolates, consecutively collected from blood-borne infections during a 10-year period all over Finland and for which detailed clinical information of the patients were available, were included. We screened the isolates by PCR for the lipooligosaccharide (LOS) locus class and for the presence of the putative virulence genes ceuE, ciaB, fucP, and virB11. The isolates were also tested for γ-glutamyl transpeptidase production. The results were analysed with respect to the clinical characteristics of the patients, and the multilocus sequence types (MLSTs) and serum resistance of the isolates. LOS locus classes A, B, and C, which carry genes for sialylation of LOS, were detected in only 23% of the isolates. These isolates were not more resistant to human serum than those with the genes of non-sialylated LOS locus classes, but were significantly more prevalent among patients with underlying diseases (p 0.02). The fucose permease gene fucP was quite uncommon, but was associated with the isolates with the potential to sialylate LOS (p <0.0001). LOS locus classes and some of the putative virulence factors were associated with MLST clonal complexes. Although some of the bacterial characteristics studied here have been suggested to be important for the invasiveness of C. jejuni, they did not explain why the clinical isolates in the present study were able to cause bacteraemia.

Decreasing trend of overlapping multilocus sequence types between human and chicken Campylobacter jejuni isolates over a decade in Finland.

We describe the long-term multilocus sequence typing (MLST) analysis of the population structure and dynamics of 454 Finnish human Campylobacter jejuni isolates, as well as 208 chicken isolates, collected during the mid-1990s to 2007. The sequence type clonal complexes (ST CC) ST-45 CC, ST-21 CC, and ST-677 CC were the most common ones found among all isolates, and they covered 73.9% of all isolates. The ST-283 CC also was found frequently among chicken isolates (8.2%). The predominant STs among all isolates were ST-45, ST-50, and ST-677. ST-137 and ST-230 were common among human isolates, and ST-267 was found more frequently among chicken isolates than human isolates. The ST-45 CC was significantly associated with chicken isolates (P < 0.01), whereas the ST-21 CC was associated with human isolates (P < 0.001). The ST-677 CC was not associated with any host (P = 0.5), and an opposite temporary trend of this complex was seen among chicken and human isolates, with an increase in the former and a decrease in the latter during the study period. Furthermore, the ST-22 and ST-48 CCs were significantly associated with human isolates (P < 0.01), but neither of the CCs was found in chicken isolates. The annual overlap between STs from human and chicken isolates decreased from 76% at the beginning of the study to 58% at the end. Our results suggest that the importance of chicken as a reservoir for strains associated with human infections has declined despite the consumption of domestic chicken meat increasing during the follow-up period by 83%.

Patient-reported complications associated with Campylobacter jejuni infection.

This study aimed to investigate the occurrence of complications, especially musculoskeletal symptoms, after sporadic Campylobacter jejuni enteritis of domestic origin in Finland. This multi-centre cross-sectional study was conducted during a seasonal peak in 2002. Questionnaires were sent to Campylobacter-positive patients, representing different geographical areas, 2 months after collection of positive stool samples. Medical records were viewed in several cases. Besides antimicrobial susceptibility testing C. jejuni isolates were serotyped. A total of 235 patients (58%) returned the questionnaire and 201 C. jejuni-positive patients were finally included in the study. Musculoskeletal symptoms associated with C. jejuni enteritis were frequent (39%); joint pain was most commonly reported (81%). The incidence of reactive arthritis was 4% and that of Achilles enthesopathy and/or heel pain was 9%. Stomach ache during enteritis was associated with the later development of joint pain. Antimicrobial treatment was common but did not prevent complications.

Severe diarrhoea caused by highly ciprofloxacin-susceptible Campylobacter isolates.

The impact of fluoroquinolone resistance of Campylobacter jejuni and Campylobacter coli isolates on the outcome of the disease in sporadic Campylobacter infections of Finnish individuals was studied. Questionnaires were sent, during a 6-month study period, to patients who were stool culture-positive for Campylobacter spp. In total, 192 returned questionnaires were analysed and assessed, together with the susceptibility data of the respective bacterial isolates. Only one (2%) of the domestic, but half of the imported, Campylobacter isolates were resistant to ciprofloxacin. Ciprofloxacin resistance was not associated with particularly severe infection. Instead, ciprofloxacin-susceptible Campylobacter isolates, as compared to ciprofloxacin-resistant isolates, showed a tendency to cause more severe infections, characterized by bloody stools and hospitalization.

Effects of anti-Helicobacter pylori treatment and probiotic supplementation on intestinal microbiota.

The aims of this study were (i) to evaluate the effect of recommended antimicrobial treatment of Helicobacter pylori infection, consisting of clarithromycin, amoxicillin and lansoprazole, on intestinal microbiota and (ii) to determine the ability of a probiotic combination containing Lactobacillus rhamnosus GG, L. rhamnosus LC705, Propionibacterium freudenreichii ssp. shermanii JS and Bifidobacterium breve Bb99 to prevent treatment-induced alterations in the intestinal microbiota. Faecal samples were obtained from 39 H. pylori-infected patients randomised into two treatment groups. In addition, 19 H. pylori-negative volunteers were included in the study as a control group. Samples were collected before, during and after treatment and microbiota were analysed by fluorescence in situ hybridisation and culture. The quantities of the predominant bacterial groups were altered significantly in both groups and disturbances were seen even 9 weeks after treatment was complete. Probiotics slightly counteracted the effects of anti-H. pylori treatment, seen as significantly less alterations in the total numbers of aerobes and lactobacilli/enterococci. At baseline, the composition of the microbiota between H. pylori-positive versus H. pylori-negative control individuals differed with regard to clostridia and the total number of anaerobes. The recommended treatment for H. pylori infection induces long-term disturbances in the intestinal microbiota. The probiotic combination appeared to result in only minor changes in the microbiota.

Strain and host characteristics of Campylobacter jejuni infections in Finland.

The relative importance of different risk-factors for Campylobacter infections and the role of bacterial strain and host characteristics are uncertain. Swimming in natural sources of water was recently described as a novel independent risk-factor for domestically-acquired Campylobacter infections. The present study investigated exposure factors and demographical characteristics (collected in a questionnaire), and determined whether Campylobacter jejuni serotypes could be linked to each other or to the severity of the disease in domestically-acquired sporadic C. jejuni infections during a seasonal peak in Finland. Swimming was associated positively with an age of

Lactobacillus bacteremia, species identification, and antimicrobial susceptibility of 85 blood isolates.

BACKGROUND: Data regarding antimicrobial susceptibility of clinical Lactobacillus isolates are scarce, and appropriate interpretation criteria for susceptibility tests are not available. METHODS: We examined 85 cases of Lactobacillus bacteremia, of which 47 cases have been included in our previous studies. Overall, 14 antimicrobial agents were evaluated by the E-test method, and these results were compared with disk diffusion test findings. The clinical outcomes of the patients and their antimicrobial treatments were registered. RESULTS: The antimicrobial susceptibility of Lactobacillus strains was species dependent. The considerable number of Lactobacillus rhamnosus (n=46), Lactobacillus fermentum (n=12), and Lactobacillus casei (n=12) strains available for testing made it possible to compare the susceptibilities within 1 species, as well. Of the 46 L. rhamnosus isolates, 22 were identified as L. rhamnosus GG type by pulsed-field gel electrophoresis. All Lactobacillus isolates demonstrated low minimum inhibitory concentrations (MICs) of imipenem, piperacillin-tazobactam, erythromycin, and clindamycin. MICs of vancomycin were high (>256 microg/mL) for all other species except Lactobacillus gasseri and Lactobacillus jensenii. Disk diffusion and E-test results were concordant. The MICs of cephalosporins varied; cefuroxime demonstrated a higher level of activity than did ceftriaxone. Benzylpenicillin and ampicillin MICs had variable ranges between different species. Combination therapy was given to 83% of the patients, but, in 54% of them, therapy included only 1 microbiologically active agent, according to results of the susceptibility tests. Mortality at 1 week was 12% among patients who presumably were receiving adequate treatment and 27% among patients who were receiving inadequate treatment (P=.131, by E-test). CONCLUSION: Most clinical Lactobacillus blood isolates demonstrated low MICs of imipenem, piperacillin-tazobactam, erythromycin, and clindamycin, but they had variable susceptibility to penicillin and cephalosporins.

IgA antibodies in persisting Helicobacter pylori infection in Finnish adults.

Most individuals infected with Helicobacter pylori have elevated levels of specific IgG antibodies, but only in about two-thirds of cases does the IgA titre exceed the cut-off level. The aim of this study was to determine whether H. pylori-infected subjects with elevated IgG levels would subsequently produce IgA antibodies, and whether elevated IgA levels increased during infection. Paired sera were available from 336 adults who took part in a large population-based health survey in 1977-1980 and a follow-up study on asthma and atopic diseases in 1997-1998 (series A). Data on paired sera from 224 adults who participated in a population-based health survey in Vammala, Finland in 1973 and who gave a follow-up blood sample in 1994 (series B) were also re-analysed. H. pylori IgG and IgA levels were determined with commercially available (series A) and in-house (series B) enzyme immunoassays. Twenty-one (35%) of the 60 subjects who initially had elevated levels of IgG antibodies only were found to be IgA-positive at follow-up. In those subjects whose baseline and follow-up samples were IgG- and IgA-positive, the median IgA levels increased by 48% and 22% in series A and B (p < 0.0001 and p 0.0241), respectively, whereas the median IgG levels did not change significantly in either series. During H. pylori infection, an increase in specific IgA was reflected by the increase in the number of responders and by the rise in titres.

Three cases of cardiac complications associated with Campylobacter jejuni infection and review of the literature.

Presented here are three cases of acute cardiac disease (myocarditis, myopericarditis, and acute atrial fibrillation) associated with Campylobacter jejuni infection, followed by a review of the corresponding literature. Since Campylobacter jejuni is the most common cause of human bacterial enteritis in developed countries, these cases emphasize the importance of keeping cardiac complications in mind when treating patients with acute gastroenteritis due to this pathogen.

Normal serum pepsinogen I levels in adults: a population-based study with special reference to Helicobacter pylori infection and parietal cell antibodies.

OBJECTIVE: Low serum pepsinogen I (PG I) values are common in subjects with advanced corpus atrophy with or without parietal cell antibodies (PCA). Elevated values are usual during Helicobacter pylori infection. MATERIAL AND METHODS: PG I levels were determined in two randomly selected cross-sectional adult population samples using the Gastroset PGI test kits. The sera (408 in 1973 and 504 in 1994), tested earlier for H. pylori infection and now for PCA, represented subjects living in Vammala, Finland. RESULTS: In the PCA-negative population, the mean (+/-SD) PG I level was significantly higher in men than in women among both H. pylori-negative (88.13+/-34.16 microg/l versus 72.43+/-29.31 microg/l; p<0.0001) and H. pylori-positive (110.50+/-50.59 microg/l, versus 97.74+/-44.82 microg/l, p<0.0001) subjects; the difference between all H. pylori-positive and -negative subjects was also significant (p<0.001). In the 10-year age groups, age had no impact on the mean PG I levels in H. pylori-negative subjects (p=0.860). In the PCA-positive population, the 10 H. pylori-positive subjects had higher mean PG I levels (112.96+/-53.62 microg/l) than the 13 H. pylori-negative subjects (32.57+/-27.59 microg/l; p=0.002); the latter mean was also significantly lower than that of the PCA- and H. pylori-negative subjects (80.08+/-32.69 microg/l; p<0.0001). CONCLUSIONS: Men had higher normal PG I values than women, but there was no significant variation by age. H. pylori infection was associated with elevated PG I levels and a small decrease with increasing age. Non-infected PCA-positive subjects showed the lowest mean PG I level.

Genetic and environmental factors in the immunopathogenesis of atopy: interaction of Helicobacter pylori infection and IL4 genetics.

BACKGROUND: Both genetic and environmental factors, e.g. early childhood infections, have a role in the pathogenesis of atopic diseases. OBJECTIVE: To examine simultaneously the strength and possible interactions of two known such factors, IL4 genetics and Helicobacter pylori infection, on the risk of atopy and asthma. METHODS: Gene polymorphism analyses and skin prick tests (SPT) were determined in 245 adult asthmatics and 405 nonasthmatic controls of population-based case-control study. SPTs were used as an indicator of atopy. H. pylori infection was verified by detecting anti-H. pylori IgG antibodies in sera. RESULTS: A significant negative association was seen between the presence H. pylori antibodies and SPT positivity (> or =1 positive reactions) in both asthmatics and controls (p = 0.002 and p = 0.025, respectively) but the effect of IL-4 polymorphism (SNP -590C/T) was nonsignificant in both groups (p = 0.071 and p = 0.072, respectively). However, IL4 genetics had an effect on susceptibility to H. pylori: asthmatics carrying the IL4 -590 allele T had a diminished risk to be H. pylori infected (OR 0.485 95%CI 0.287-0.819). This effect was not seen in controls. Logistic regression analysis indicated that H. pylori and IL4 effects on atopy risk are not interdependent. CONCLUSIONS: This study showed that the effect of H. pylori infection on atopy risk is stronger than that of IL4 genetics. There is no interaction between these factors on the pathogenesis of atopy suggesting that these factors have distinct immunopathogenetic mechanisms. However, the genetic effect may modify the role of infective agents by effecting on susceptibility to disease.

Probiotic supplementation improves tolerance to Helicobacter pylori eradication therapy--a placebo-controlled, double-blind randomized pilot study.

BACKGROUND: H. pylori is the major cause of chronic gastritis, and a risk factor for peptic ulcer and gastric cancer. AIM: To investigate the effect of probiotic supplementation on the tolerance and efficacy of H. pylori eradication treatment in a randomized, double-blind, placebo-controlled trial. METHODS: A total of 338 volunteers were screened for H. pylori infection. The eligibility criteria were met by 47 subjects whose H. pylori infection was verified at the outset and re-evaluated after the treatment by the 13C-urea breath test and by enzyme immunoassay serology. The subjects were randomized to receive probiotic therapy (Lactobacillus rhamnosus GG, L. rhamnosusLC705, Bifidobacterium breve Bb99 and Propionibacterium freudenreichii ssp. shermanii JS) or a placebo during H. pylori eradication and for 3 weeks following the treatment, and recorded their daily symptoms in a standardized diary. RESULTS: When the frequencies of new or aggravated symptoms were evaluated, no significant differences were found between the two groups for individual symptoms. However, the probiotic group showed less treatment-related symptoms as measured by the total symptom score change (P = 0.038) throughout the H. pylori eradication therapy in contrast to the placebo group. The H. pylori eradication rate was non-significantly higher in the group receiving probiotic therapy (91% vs. 79%, P = 0.42). In this group the recovery of probiotic bacteria in the faeces increased significantly (P < 0.001). CONCLUSIONS: In this pilot study, probiotic supplementation did not diminish significantly the frequency of new or aggravated symptoms during H. pylori eradication. However, our data suggest an improved tolerance to the eradication treatment when total symptom severity was taken into account. Furthermore, the results show that probiotic bacteria are able to survive in the gastrointestinal tract despite the intensive antimicrobial therapy.

Inflammation and cytokeratin 7/20 staining of cardiac mucosa in young patients with and without Helicobacter pylori infection.

BACKGROUND: Both Helicobacter pylori and gastro-oesophageal reflux disease (GORD) may cause inflammation in cardiac mucosa. Intestinal metaplasia (IM) is found more often in GORD associated inflammation than in inflammation caused by H pylori, especially in young individuals. AIM: To examine morphological differences in chronic inflammation in these two conditions by immunohistochemistry. PATIENTS/METHODS: Tissue blocks from cardiac mucosa of patients <45 years were available as follows: 10 patients with chronic inflammation of cardiac mucosa (carditis) and H pylori gastritis (group 1); 10 patients with (possibly GORD related) carditis, but normal antrum and corpus (group 2); and 10 patients with non-inflamed cardiac mucosa and normal antrum and corpus (group 3). Haematoxylin and eosin staining and immunohistochemical staining for various inflammatory cells were performed for patients in groups 1 and 2 as follows: CD20 (B cells), CD3 (T cells), CD4 (T helper cells), CD8 (T suppressor cells), CD163 (macrophages), CD138 (plasma cells), and CD117 (mast cells). For all patients, cytokeratin 7/20 (CK7/20) staining was performed. RESULTS: No clear differences were seen in the morphology of chronic inflammation between groups 1 and 2. In both, plasma cells were most abundant. CK7/20 staining showed no differences between these groups. CONCLUSION: Helicobacter pylori negative (possibly GORD associated) and H pylori related carditis cannot be distinguished on a morphological basis. The stronger tendency towards IM in the first entity cannot be explained by differences in the type of inflammation. Barrett-type CK7/20 staining seems typical for cardiac mucosa, irrespective of the type of inflammation or presence of IM.

First-line eradication therapy for Helicobacter pylori in primary health care based on antibiotic resistance: results of three eradication regimens.

AIM: To determine the efficacy of three Helicobacter pylori eradication regimens and factors affecting the eradication results in Finland. METHODS: A total of 342 H. pylori-positive adult patients from primary health care referred for gastroscopy at 23 centres in different parts of Finland were randomized to receive either (i) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and metronidazole 400 mg t.d.s. (LAM), (ii) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC), or (iii) ranitidine bismuth citrate 400 mg b.d., metronidazole 400 mg t.d.s. and tetracycline 500 mg q.d.s. (RMT). A (13)C-urea breath test was performed 4 weeks after therapy. RESULTS: The eradication result could be assessed in 329 cases. Intention-to-treat cure rates of LAM, LAC, and RMT were 78, 91 and 81%. The difference was significant between LAM and LAC (P = 0.01) and between LAC and RMT (P = 0.04). The eradication rates in cases with metronidazole-susceptible vs. -resistant isolates were for LAM 93% vs. 53% (P = 0.00001), for LAC 95% vs. 84%, and for RMT 91% vs. 67% (P = 0.002). Previous antibiotic use, smoking, and coffee drinking reduced the efficacy of therapy. CONCLUSIONS: In unselected patients in primary health care, LAC was the most effective first-line eradication.

Age-dependent accuracy of Helicobacter pylori antibody assays for adults, with special emphasis on atrophic gastritis.

The accuracy of Helicobacter pylori antibody assays for 561 consecutive adult outpatients who had undergone gastroscopy was studied. The sensitivity of an immunoglobulin G test was 99 to 100% for all age groups, but the specificity declined by age group, from 99% for those aged 15 to 49 years to 75% for those aged > or =65 years. The exclusion of false-positive results for patients with atrophic gastritis improved the specificity to 93 to 97% for the older age groups.