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.

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.

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.

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 <or= 5 years, and C. jejuni serotype Pen 6,7 was found significantly more frequently among patients who reported swimming. The geographical distribution among serotypes differed, in that 54% of the isolates belonging to the Pen 4 complex serotype were identified in the Helsinki area, and 74% of the Pen 21 isolates were from the Kuopio area. Pen 57 was associated with a disease of shorter duration, but no serotype could be linked to hospitalisation or antimicrobial therapy. However, advanced age was associated with hospitalisation and a longer period of hospitalisation. Risk-factors and sources of infection for C. jejuni infection may not be identical for all individuals. This study supports the concept that individuals belonging to different age groups and living in different geographical areas may acquire C. jejuni infections from different sources.

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.

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.

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.

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.

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.

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.

An outbreak of gastroenteritis from a non-chlorinated community water supply

STUDY OBJECTIVE

To determine the source and the extent of a community wide outbreak of gastroenteritis.

DESIGN

A matched case-control study with postal questionnaires. Subtyping of campylobacter strains by pulsed field gel electrophoresis (PFGE).

SETTING

A rural municipality with a population of 8600 in southern Finland, August 2000. Two thirds of the population receive non-chlorinated ground water from the municipal water supply.

PARTICIPANTS

Cases were randomly selected among residents of the municipality who contacted the municipal health centre because of gastroenteritis and had illness onset between 31 July and 20 August 2000. Community controls were identified from the population registry and matched according to sex, year of birth, and postal code.

MAIN RESULTS

Four hundred and sixty three persons contacted the municipal health centre because of gastroenteritis. Campylobacter jejuni was isolated from stool samples of 24 persons. One hundred and thirty seven cases and 388 controls were enrolled in the case-control study. In multivariate analysis, drinking unboiled water from the municipal supply was significantly associated with illness (odds ratio 11.1, 95% confidence interval 1.4 to 90.2). C jejuni was isolated from one tap water sample. The water isolate and all but one of the patient isolates were indistinguishable by PFGE.

CONCLUSIONS

Combining epidemiological investigation with molecular subtyping methods provided strong evidence that water was the source of the outbreak. Non-chlorinated small ground water systems may be susceptible to waterborne outbreaks and constitute a risk to rural populations.

Temporal and geographical distribution and overlap of Penner heat-stable serotypes and pulsed-field gel electrophoresis genotypes of Campylobacter jejuni isolates collected from humans and chickens in Finland during a seasonal peak

The association of Penner heat-stable serotypes and pulsed-field gel electrophoresis genotypes of 208 human and 30 chicken Campylobacter jejuni isolates was studied. Overall, 46% of the human strains had overlapping sero- and genotype combinations with chicken strains. The percentage was reduced to 31% for strains that were considered temporally related. This suggests common environmental sources.

Detection and typing of Campylobacter jejuni and Campylobacter coli and analysis of indicator organisms in three waterborne outbreaks in Finland

Waterborne outbreaks associated with contamination of drinking water by Campylobacter jejuni are rather common in the Nordic countries Sweden, Norway, and Finland, where in sparsely populated districts groundwater is commonly used without disinfection. Campylobacters, Escherichia coli, or other coliforms have rarely been detected in potential sources. We studied three waterborne outbreaks in Finland caused by C. jejuni and used sample volumes of 4,000 to 20,000 ml for analysis of campylobacters and sample volumes of 1 to 5,000 ml for analysis of coliforms and E. coli, depending on the sampling site. Multiple samples obtained from possible sources (water distribution systems and environmental water sources) and the use of large sample volumes (several liters) increased the chance of detecting the pathogen C. jejuni in water. Filtration of a large volume (1,000 to 2,000 ml) also increased the rate of detection of coliforms and E. coli. To confirm the association between drinking water contamination and illness, a combination of Penner serotyping and pulsed-field gel electrophoresis (digestion with SmaI and KpnI) was found to be useful. This combination reliably verified similarity or dissimilarity of C. jejuni isolates from patient samples, from drinking water, and from other environmental sources, thus confirming the likely reservoir of an outbreak.

Inflammation and intestinal metaplasia at the squamocolumnar junction in young patients with or without Helicobacter pylori infection

BACKGROUND

Intestinal metaplasia (IM) in the oesophagus is a known risk factor for adenocarcinoma of the oesophagus. The incidence of adenocarcinoma of the cardia and oesophagus has increased in Western countries simultaneously with a decrease in Helicobacter pylori prevalence.

AIMS

To determine the association of H pylori infection with inflammation and IM at the squamocolumnar junction (SCJ) in young individuals.

PATIENTS

A total of 168 (121 women; 72%) consecutive outpatients, </=45 years, undergoing gastroscopy, and with no prior H pylori eradication treatment.

METHODS

Biopsy specimens taken from the antrum, corpus, SCJ, and oesophagus were assessed according to the updated Sydney system, and type of IM (complete or incomplete) was determined. Serum samples from H pylori positive patients were studied for CagA antibodies.

RESULTS

In 86% of 37 patients with gastritis in the antrum and/or corpus (24 histologically H pylori positive) and in 23% of 125 patients with a healthy stomach, inflammation was present in the glandular mucosa at the SCJ. In the latter, cardiac mucosa more often than fundic mucosa at the SCJ was inflamed (p<0.001), the inflammation was usually milder in nature, and was associated with signs of reflux disease. IM (incomplete or complete) at the SCJ was evident in nine of those 24 with a healthy stomach and inflamed cardiac mucosa at the SCJ but in none of those with H pylori gastritis.

CONCLUSIONS

IM at the SCJ can also appear in young individuals in whom it seems to be associated with reflux related isolated inflammation in cardiac mucosa at the SCJ but not with H pylori gastritis.

The course of Helicobacter pylori infection in kidney transplantation patients

BACKGROUND

Helicobacter pylori has been found to be only a minor risk factor for gastroduodenal complications in kidney transplantation patients. The aim of the study was to follow up the course of H. pylori infection in a group of immunosuppressed kidney transplantation patients.

METHODS

After a median follow-up of 6.8 years, control serum samples were taken from 93 originally seropositive and 88 originally seronegative kidney transplant recipients. H. pylori antibodies of the IgG and IgA classes and serum pepsinogen I levels were measured from pretransplant and follow-up samples in parallel. In addition, CagA antibodies were measured from the baseline samples of the seropositive patients.

RESULTS

83 of the 93 seropositive patients were also cagA-positive. In addition to the 10 patients who received H. pylori eradication therapy, 27 (29%) of the 92 patients with originally elevated H. pylori IgG antibody titres showed IgG titres at normal level or levels decreased by more than 70% and below 2000 (regarded as seroreverters) after the follow-up. One of the originally seronegative patients seroconverted during the study period. After transplantation, the decrease of serum pepsinogen I values was in accordance with improved kidney function. Patients with lower serum pepsinogen I levels before the transplantation seroreverted more easily.

CONCLUSIONS

A spontaneous H. pylori seroreversion occurred in 29% of the immunosuppressed kidney transplantation patients. After a successful kidney transplantation, serum pepsinogen I values declined significantly.

Intraluminal casein model of necrotizing enterocolitis for assessment of mucosal destruction, bacterial translocation, and the effects of allopurinol and N-acetylcysteine

An intraluminal casein model (ICM) of necrotizing enterocolitis (NEC) is able to produce small-bowel changes reminiscent of human NEC in neonatal animals. We studied bacterial translocation (BT) in NEC induced by using the ICM in neonatal piglets. We also studied whether allopurinol (AL) and N-acetylcysteine (NAC) have an effect on BT and mucosal changes in the ICM of NEC. Twenty-eight neonatal piglets were randomized into four groups. NEC was induced in 21 by injecting casein-d-gluconate into a loop of terminal ileum: group Cas (n = 7) had no premedication, in group Cas/AL (n = 7) intravenous (i.v.) Al (100 mg/kg), and in group Cas/NAC (n = 7) i.v. NAC (200 mg/kg) was given. Group Sham (n = 7) had the ileum injected with 0.9% saline with no premedication. Immediately after the injection a mesenteric lymph node (MLN) adjacent to the loop was harvested for quantitative aerobic bacterial culture; 4 h after the injection another MLN and samples of spleen, liver, kidney, and lung were harvested and cultured. Comparison of the incidence of samples with positive bacterial cultures and the number of colony-forming units (CFU) in samples was made between groups. The severity of NEC in the ileum was graded from 0 to 3 according to macroscopic and histologic findings. NEC changes in the bowel were most severe in Cas piglets, less severe in Cas/NAC piglets ( P < 0.5), and sham piglets had the least severe changes ( P < 0.05). piglets with NEC changes in the ileum had a higher incidence of BT into the MLN than piglets without NEC changes ( P < 0.05), but the difference in CFU was not significant ( P > 0.05). In Cas and Cas/NAC piglets a high incidence of BT into the MLN was noted as early at -5 min after casein injection. The incidence of BT into the MLN was significantly higher in Cas and Cas/NAC piglets than in Sham piglets ( P < 0.05), the difference in CFU being not significant ( P > 0.05). BT in Cas/Al piglets was not significantly different from that of Cas piglets ( P > 0.05), but less than in Cas/NAC piglets ( P < 0.05). Four hours after casein injection into the ileum there was significant BT into the MLN. Premedication with NAC was associated with less severe NEC changes, but neither NAC nor AL significantly affected BT.

Dental caries is common in Finnish children infected with Helicobacter pylori

Childhood factors such as low socioeconomic status are risk factors for Helicobacter pylori infection and Streptococcus mutans-related dental caries. We examined whether H. pylori infection and dental caries are present today in the same group of children examined previously. We reviewed the public dental health service files of 21 H. pylori-positive children (upper gastrointestinal endoscopy at a median age of 13.5 y) and 27 H. pylori-negative children (endoscopy at a median age of 12.5 y) examined during 1995-98 at the Helsinki University Central Hospital, Finland. All H. pylori-positive children had experienced dental caries in their primary or permanent teeth or in both whereas among H. pylori-negative children the respective proportion was 70% (p < 0.01). At the age of 7 y, 18% (3/17) of the H. pylori-positive children had experienced caries in permanent teeth as compared to 0% among H. pylori-negative children (0/24; p < 0.05). At the age of 12 y, H. pylori-positive children had more decayed, missing or filled permanent teeth than H. pylori-negative children (80% vs. 38%; p < 0.05). Although a causal relationship between H. pylori and dental caries is unlikely, it is possible that H. pylori-infected children have an increased risk of other health problems, such as dental caries, for which proper treatment is needed.

The effect of Helicobacter pylori eradication on the natural course of atrophic gastritis with dysplasia

BACKGROUND

There are few data on the natural course of Helicobacter pylori-related atrophic gastritis.

AIM

To investigate the effect of H. pylori eradication on advanced atrophic gastritis in the corpus.

METHODS

Twenty-two elderly men with H. pylori infection and moderate or severe atrophic corpus gastritis formed the study population. These men were under endoscopic surveillance because of the presence of indefinite or definite dysplastic gastric lesions in addition to atrophic corpus gastritis. The men were gastroscopically and bioptically examined four times before they received H. pylori eradication therapy (mean follow-up time, 7.5 years), and once again 2.5 years after eradication therapy. Serum levels of pepsinogen I and H. pylori antibodies were analysed at baseline, immediately before and 2.5 years after eradication therapy.

RESULTS

During the 7.5-year period prior to eradication therapy, no significant changes were observed in the mean atrophy and intestinal metaplasia scores or in the mean serum level of pepsinogen I. However, a significant improvement occurred in the mean histological scores of inflammation (from 2.2 to 0.5), atrophy (from 2.2 to 1.2) and intestinal metaplasia (from 1.6 to 1.1) in the corpus mucosa after H. pylori eradication. In addition, the mean serum level of pepsinogen I increased from 16.3 to 25.7 microg/L (P=0.0071, Wilcoxon signed rank test) after eradication therapy.

CONCLUSIONS

The results suggest that advanced atrophic corpus gastritis (and intestinal metaplasia) improves and may even heal after the eradication of H. pylori.

Evidence that cagA(+) Helicobacter pylori strains are disappearing more rapidly than cagA(-) strains

BACKGROUND AND AIMS

The prevalence of Helicobacter pylori colonisation in populations in developed country has been declining, as shown by community based serological surveys of adults in Vammala, Finland in 1973 and 1994. In this study, we determined whether the proportion of subjects colonised by cagA(+) or cagA(-) H pylori strains has changed as the overall prevalence of H pylori(+) has declined.

METHODS

We examined 911 sera from Vammala's study for antibodies to the CagA antigen of H pylori using a truncated CagA protein as the antigen in an ELISA and we examined the trend in acquisition and carriage of cagA(+) strains.

RESULTS

As expected, the prevalence of carriage of both cagA(+) and cagA(-) strains fell between 1973 and 1994 (p<0.001). However, the prevalence of cagA(+) strains among those <45 years declined (34% to 8%) significantly (p<0.001) more than for cagA(-) strains (12% to 6%). Of 221 subjects with paired serum samples, 12 (5.4%) changed H pylori status; the estimated seroconversion and reversion rates were 0.4% and 0.13% per year, respectively. Except for the few individuals who changed serostatus, absolute antibody levels to H pylori antigens, including CagA, changed little over the 21 year period.

CONCLUSIONS

The decline in CagA seroprevalence predominantly reflects declining acquisition of cag(+) strains in younger subjects. In addition, these data confirm that H pylori acquisition chiefly occurs during childhood but continues to occur during adulthood, albeit at low rates, in developed countries.

Campylobacter-triggered reactive arthritis: a population-based study

OBJECTIVE

To study the incidence and clinical picture of Campylobacter-associated reactive arthritis (ReA) and other reactive musculoskeletal symptoms in the population.

METHODS

A questionnaire on enteric and extraintestinal, including specifically musculoskeletal, symptoms was sent to 870 consecutive patients with Campylobacter-positive stool culture and 1440 matched controls. Analysis of self-reported musculoskeletal symptoms with clinical examination was performed.

RESULTS

Forty-five of the patients (7%) had ReA and eight (1%) had reactive tendinitis, enthesopathy or bursitis. No child had ReA. The arthritis was oligo- or polyarticular, and, in most cases, mild. HLA-B27 was positive in 14% of ReA patients. Of the 45 ReA patients, 37 had C. jejuni and 8 had C. coli infection. No controls had ReA.

CONCLUSION

ReA is common following Campylobacter infection, with an annual incidence of 4.3 per 100000. At the population level, acute ReA is mild, more frequent in adults, and not associated with HLA-B27. Besides C. jejuni, C. coli can trigger ReA.

Should Helicobacter pylori infection be treated before kidney transplantation?

BACKGROUND

Before the introduction of modern medication for ulcer disease, gastroduodenal complications were often fatal in recipients of kidney transplants. Helicobacter pylori causes gastritis and is an important risk factor for peptic ulcer disease and gastric malignancies. The aim of this study was to evaluate whether H. pylori infection influences the outcomes of kidney transplantation.

METHODS

Between 1991 and 1994, serum H. pylori antibodies were determined in samples taken just before transplantation from 500 consecutive recipients of kidney transplants. Clinical data were collected retrospectively by means of questionnaires sent to the patients and from the national kidney transplantation registry.

RESULTS

The prevalence of seropositivity of H. pylori was 31% in the 500 renal transplant subjects, and the seropositivity increased with age. There were no differences in patient or graft survival between the seronegative and seropositive patients. During the first 3 months after transplantation, five seronegative and one seropositive patient had gastroduodenal ulcers, with bleeding complications in three of the seronegative ones. After 3 months, there were more ulcers in the seropositive group (6 vs 3%) and more oesophagitis in the seronegative group (9 vs 7%). During the 6-year follow-up, two cases of gastroduodenal malignancies were found in the helicobacter-positive group and none in the seronegative group.

CONCLUSIONS

Helicobacter pylori infections did not result in significant postoperative gastric complications. Two of the 155 seropositive patients developed gastroduodenal malignancies.

Serologic diagnosis of Helicobacter pylori infection in outpatients aged 45 years or less

The diagnostic accuracy of serological tests for Helicobacter pylori was studied in 145 consecutive outpatients aged 45 years or less referred for gastroscopy. Helicobacter pylori infection can be detected by serological tests, including rapid whole-blood tests. The low prevalence of the disease in young people may have a negative effect on the positive predictive value of a test. In this study, the presence of Helicobacter pylori was assessed by a biopsy urease test and histological examination, and by several serological tests: a rapid whole-blood test on fingerstick blood, a latex agglutination serum test, a commercial enzyme immunoassay (EIA) test, and an in-house EIA for detection of antibodies of both the IgG and IgA classes. Helicobacter pylori infection was diagnosed with invasive tests in 21 (14.5%) patients. The sensitivity, specificity, and positive and negative predictive values of the EIA-based tests, compared to histological examination, were 100%, 96-97%, 81-84%, and 100%, respectively. The positive predictive value of the latex agglutination test was 78%, whereas it was only 47% for the whole-blood rapid test used. Although the results of the whole-blood rapid test were unsatisfactory, the quantitative EIA-based tests could reliably detect Helicobacter pylori among young patients, in whom the prevalence of the infection is low.

Good adhesion properties of probiotics: a potential risk for bacteremia?

The ability to adhere to human intestinal mucus was tested for lactic acid bacteria of clinical blood culture, human fecal and dairy origin. The blood culture isolates were found to adhere better than the dairy strains. Of the Lactobacillus rhamnosus strains (nine clinical, 10 fecal and three dairy), blood culture isolates adhered better than the fecal strains. Although these results indicate a trend for blood culture isolates to bind to intestinal mucus in higher numbers than strains of dairy and human fecal origin, other factors are also likely to be involved in the etiology of lactobacillemia since some of the clinical Lactobacillus isolates exhibited a relatively low level of adhesion.

Genomic relatedness within five common Finnish Campylobacter jejuni pulsed-field gel electrophoresis genotypes studied by amplified fragment length polymorphism analysis, ribotyping, and serotyping

Thirty-five Finnish Campylobacter jejuni strains with five SmaI/SacII pulsed-field gel electrophoresis (PFGE) genotypes selected among human and chicken isolates from 1997 and 1998 were used for comparison of their PFGE patterns, amplified fragment length polymorphism (AFLP) patterns, HaeIII ribotypes, and heat-stable (HS) serotypes. The discriminatory power of PFGE, AFLP, and ribotyping with HaeIII were shown to be at the same level for this selected set of strains, and these methods assigned the strains into the same groups. The PFGE and AFLP patterns within a genotype were highly similar, indicating genetic relatedness. The same HS serotypes were distributed among different genotypes, and different serotypes were identified within one genotype. HS serotype 12 was only associated with the combined genotype G1 (PFGE-AFLP-ribotype). These studies using polyphasic genotyping methods suggested that common Finnish C. jejuni genotypes form genetic lineages which colonize both humans and chickens.

Decreasing prevalence of helicobacter antibodies in Finland, with reference to the decreasing incidence of gastric cancer

Time trends and geographical variation of Helicobacter pylori antibodies in Finland were investigated by enzyme immunoassay in 20- to 34-year-old randomly selected females from six localities during 1969-73 (n = 375), and 15- to 45-year-old females representing nine communities and four geographical areas in 1983 (n = 882) and 1995 (n = 842). In the six communities investigated at three different time points, the overall prevalence declined from 38 to 12%, with an emphasis on the latter 12 years. The regionally varying rate of decrease in helicobacter prevalence changed the pre-existing geographical variation, leaving northern Finland with the highest rate. A 10%-units higher local helicobacter prevalence seemed to predict a 23% (95% CI 3-44%) higher gastric cancer incidence 20 years later. The overall decline in helicobacter seropositivity is consistent with earlier reports from Finland and other developed countries, and supports the cohort theory as an explanation for the age-related increase in H. pylori seroprevalence.

Survival of Helicobacter pylori From complement lysis by binding of GPI-anchored protectin (CD59)

BACKGROUND & AIMS

Although Helicobacter pylori is sensitive to complement lysis in vitro, chronic infection persists for years. We tested whether H. pylori acquires complement resistance by binding glycolipid-tailed inhibitors from the host.

METHODS

Gastric biopsy specimens from H. pylori-infected patients (n = 10) and noninfected controls (n = 6) were analyzed for complement deposition and expression of the complement regulators protectin (CD59) and DAF. Protectin binding and complement sensitivity analyses were performed with the NCTC strain 11637 (CagA(+)) and 2 clinical isolates 9:0 (CagA(+)) and 67:20 (CagA(-)).

RESULTS

In the noninfected mucosa, protectin was strongly expressed on the membranes of epithelial cells, but in the infected epithelia the expression was granular and more focused to the mucus. H. pylori bacteria in the gastric pits were often positive for protectin but negative for C5b-9. An opposite pattern was seen on the surface mucosa. In vitro analyses using (125)I-CD59 and bacteriolysis assays showed that protectin bound to H. pylori and protected CagA(+) strains against complement killing. In an enzyme-linked immunosorbent assay, the binding of CD59 correlated inversely with the appearance of the C5b-9 neoantigen.

CONCLUSIONS

Binding of protectin inhibits membrane attack complex assembly on H. pylori and may thereby contribute to their survival on the gastric mucosa.

Campylobacters: the most common bacterial enteropathogens in the Nordic countries

Campylobacters have been known as important human pathogens since the late 1970s. Campylobacter jejuni and coli are the most common bacterial enteropathogens in the developed countries. During the past years an increasing incidence of campylobacteriosis has been reported in many developed countries. C. jejuni is the most common Campylobacter species while C. coli accounts for about 5-10% of the cases. Although the genome of C. jejuni NCTC 11168 strain was sequenced recently, the exact pathogenetic mechanisms are still not known. Furthermore, there are no reliable animal models available. The epidemiology of this common infection is not well understood; however, eating and handling poultry, contaminated drinking water, and contact with pet animals have been recognized as important risk factors. Most of the cases are sporadic although large water-borne outbreaks have also been reported. Discriminatory typing methods are helpful in tracing the sources and transmission routes. In addition to traditional serotyping, genotyping methods, such as pulsed-field gel electrophoresis, have been developed. As Campylobacter infections probably precede Guillan-Barré syndrome in many cases, a great interest has lately been focused on the possible triggering mechanisms underlying this phenomenon.

cagA, vacA and iceA virulence genes of Helicobacter pylori isolates of children in Finland

cagA, vacA s and m genotypes and iceA alleles were analyzed from Helicobacter pylori strains isolated from 17 Finnish children and 32 children of non-Finnish origin living in Finland. Twelve children in the latter group were eastern European and 15 were of African origin. Only three children of non-Finnish origin were born in Finland. The vacA sla subtype was more prevalent in the isolates from Finnish children than African children (76% vs. 7%, P<0.001); vacA s1b frequencies were 5% and 67%, respectively (P<0.001). The iceA1 allele was significantly more prevalent in African than Finnish isolates (93% vs. 35%, P< 0.01). Considerable variation was noted in the frequency of vacA s1 subtypes and iceA alleles in children originating from different geographic regions, but the geographic variation of s1 subtypes resembled that described in other reports.

Cure of Helicobacter pylori infection after failed primary treatment: one-center results from 120 patients

BACKGROUND

Treatment with a proton pump inhibitor (PPI) and antimicrobials cures Helicobacter pylori infection in about 90% of patients. This is a retrospective overview of our studies aiming to cure the infection in all compliant patients with failed initial therapy.

METHODS

We retreated 120 (19% of 644) H. pylori-infected patients whose initial therapy had failed. The retreatments included (i) triple therapy (TT): colloidal bismuth subcitrate, metronidazole, amoxicillin (or tetracycline); (ii) quadruple therapy (QT): TT and a PPI; or (iii) high doses of both a PPI and clarithromycin combined with a further 1-3 individually selected antimicrobials. The eradication results were determined after 6-12 months.

RESULTS

The 1st retreatment was successful in 70 of 120 patients. The 2nd retreatment cured 25 of the remaining 42 patients, the 3rd 13 of 17, and the 4th the last 4 patients. The cumulative eradication rate (ITT) was 93% (95% CI: 88.9%-97.9%; 8 patients withdrew after a failed 1st retreatment) and the rate was 100% in the remaining 112 patients who accepted several retreatments. The 1st retreatment with TT cured 23% (95% CI: 12%-34%) of 57 patients and QT 85% (95% CI: 74%-96%) of 41 patients who had initially undergone a failed metronidazole-based treatment. All retreatments were well tolerated.

CONCLUSIONS

In this study, high doses of a PPI and clarithromycin combined with 1-3 antimicrobials according to susceptibility data proved to be the best drug combination in the cure of H. pylori infection after failed primary treatment. Giving imidazole- and bismuth-based QT (without clarithromycin) as the first-line treatment of H. pylori infection ensures that the number of failures remains low.

Evaluation of blood tests to predict normal gastric mucosa

BACKGROUND

To determine the accuracy of blood tests in predicting normal gastric mucosa confirmed by histological examination of gastric biopsy specimens.

METHODS

In total, 207 consecutive patients referred for upper endoscopy were included. Two biopsy specimens each from the antrum and corpus were assessed histologically for the presence of Helicobacter pylori, gastritis, and atrophy. Serum samples were studied for H. pylori antibodies by enzyme immunoassay (Pyloriset EIA-G and EIA-A) and by a rapid latex agglutination test (Pyloriset Dry); pepsinogen I was measured by an immunoenzymometric assay (Gastroset PGI), gastrin by radioimmunoassay, and parietal cell antibodies by indirect immunofluorescence.

RESULTS

In 101 (49%) of 207 patients, the gastric mucosa on histologic examination was normal. In the 63 patients aged 45 years or less, H. pylori IgG serology was negative in all 47 patients with normal gastric mucosa and none had low serum pepsinogen I levels. Among 144 patients over age 45 years, 72 had negative H. pylori IgG serology. Combining the serum pepsinogen I assay with the results of H. pylori IgG serology, 12 patients with normal serology but low serum pepsinogen I were found. Thus, 60 patients, 52 of whom showed normal gastric histology, had normal IgG serology and serum pepsinogen 1. In the remaining eight patients with normal blood tests, the histologic changes were very mild.

CONCLUSIONS

Although negative H. pylori IgG serology alone in younger patients, and in combination with normal serum pepsinogen I levels in older patients, reliably predicted the presence of normal gastric mucosa, gastroscopy is still recommended for patients over 45 years.

A three-year study of Campylobacter jejuni genotypes in humans with domestically acquired infections and in chicken samples from the Helsinki area

Campylobacter jejuni isolates from stool samples of patients with domestically acquired sporadic infections and from chicken from retail shops were studied during seasonal peaks from June to September over a 3-year period from 1996 to 1998. A large number of pulsed-field gel electrophoresis (PFGE) genotypes (a combined SmaI-SacII pattern) were identified each year. Certain genotypes persisted for the whole study period, and predominant genotypes represented 28 to 52% of the strains during a restricted period of time. The peak level of positive chicken samples was between July and August of each study year, when 10 to 33% of the samples were positive for campylobacter. The same PFGE genotypes found in humans were also detected in the chicken samples. This suggests that common genotypes were circulating in the area.

Co-expression in Helicobacter pylori of cagA and non-opsonic neutrophil activation enhances the association with peptic ulcer disease

AIMS

To investigate the association of cagA positivity and non-opsonic neutrophil activation capacity in wild-type Helicobacter pylori strains with peptic ulcer disease or chronic gastritis only.

METHODS

Helicobacter pylori were isolated from antral biopsies of 53 consecutive patients with chronic antral gastritis, of whom 24 had peptic ulcer disease endoscopically. The presence of cagA, a marker for the cag pathogenicity island, was determined by polymerase chain reaction with specific oligonucleotide primers, and non-opsonic neutrophil activation capacity by luminol enhanced chemiluminescence.

RESULTS

The cagA gene was present in 39 of 53 (73.6%) strains, 20 of which (83.3%) were from the 24 patients with peptic ulcer disease and 19 (65.5%) from the 29 patients with chronic gastritis only. Non-opsonic neutrophil activation was found in 29 (54.7%) strains, 16 of which (66.7%) were from patients with peptic ulcer disease, and 13 (44.8%) from those with chronic gastritis. Non-opsonic neutrophil activation was found more frequently in cagA+ than cagA- strains (59% v 42.9%). Whereas four of the 14 cagA- strains and eight of the 24 non-opsonic neutrophil activation negative strains were from patients with peptic ulcer disease, only two of 24 (8.3%) peptic ulcer disease strains expressed neither cagA nor non-opsonic neutrophil activation. The cagA gene and non-opsonic neutrophil activation capacity were co-expressed in 14 of 24 (58.3%) strains from patients with peptic ulcer disease, and in nine of 29 (31%) strains from individuals with chronic gastritis.

CONCLUSIONS

Positivity for cagA and non-opsonic neutrophil activation occur independently in wild-type H pylori strains. However, co-expression of the two markers enhanced the prediction of peptic ulcer disease.

Atrophic gastritis and Helicobacter pylori infection in outpatients referred for gastroscopy

BACKGROUND

Atrophic gastritis has been shown to be one of the long term sequelae of Helicobacter pylori infection.

AIMS

To determine the prevalence of atrophic gastritis in outpatients, to study the accuracy of serological methods for revealing atrophy, and to define the association of H pylori infection with atrophic gastritis in these patients.

PATIENTS/METHODS

A total of 207 consecutive outpatients referred for gastroscopy were included. Biopsy specimens from the antrum and corpus were assessed histologically according to the Sydney system. Serum samples were studied for H pylori IgG and IgA antibodies by enzyme immunoassay, CagA antibodies by immunoblot, pepsinogen I by an immunoenzymometric assay, gastrin by radioimmunoassay, and parietal cell antibodies by indirect immunofluorescence.

RESULTS

Histological examination revealed atrophic gastritis in 52 (25%) of 207 patients. H pylori and CagA antibodies were strongly associated with atrophic antral gastritis but poorly associated with atrophic corpus gastritis. Low serum pepsinogen I was the most sensitive and specific indicator of moderate and severe atrophic corpus gastritis. All six patients with moderate atrophic corpus gastritis had H pylori infection but eight of 10 patients with severe atrophic corpus had increased parietal cell antibodies and nine had no signs of H pylori infection.

CONCLUSIONS

Atrophic antral gastritis was strongly associated with CagA positive H pylori infection. Severe atrophic corpus gastritis was not determined by H pylori tests but low serum pepsinogen I, high gastrin, and parietal cell antibodies may be valuable in detecting these changes.

Parietal cell antibodies and Helicobacter pylori in children

BACKGROUND

Gastric autoantibodies are common in Helicobacter pylori-infected adults, and the presence of these antibodies is associated with atrophic gastritis. The role of H. pylori in the autoimmune type of atrophic gastritis is unresolved, and it is not known at what stage the autoantibodies appear in serum during H. pylori infection. Therefore, we screened children with and without H. pylori infection for gastric parietal cell antibodies.

METHODS

Seventy-one children with H. pylori infection verified by examination of gastric biopsy specimens (mean age, 9.4 years), 8 children with positive serology but negative histology for H. pylori (mean age, 11.6 years), and 130 children with negative serology for H. pylori (mean age, 7.7 years) were screened for the presence of gastric parietal cell antibodies in serum by indirect immunofluorescence. In addition, 61 children with celiac disease (mean age, 7.1 years) were screened for gastric parietal cell antibodies and H. pylori antibodies.

RESULTS

None of the children with H. pylori infection had gastric parietal cell antibodies in serum. Only three positive parietal cell antibody reactions were found: a 14-year-old boy with positive serology for H. pylori but no other signs of infection (titer 5000), a 14-year-old girl with tuberculosis (titer 1250, seronegative for H. pylori) and a 10-year-old girl with insulin-dependent diabetes mellitus (titer 6250, seronegative for H. pylori).

CONCLUSIONS

Although gastric autoantibodies are often found in adults with chronic H. pylori gastritis, it seems that H. pylori-infected children are not positive for gastric parietal cell antibodies. It remains to be studied in which H. pylori infections and at what stages gastric autoantibodies appear.

Diagnosis of Helicobacter pylori infection in patients with atrophic gastritis: comparison of histology, 13C-urea breath test, and serology

BACKGROUND

Atrophic gastritis, a risk factor for gastric cancer, is a late consequence of Helicobacter pylori infection in approximately one-third of the infected patients. It has been suggested that gastric cancer would develop less frequently if H. pylori were eradicated. However, the prevalence of H. pylori infection may be underestimated in patients with atrophic gastritis and intestinal metaplasia if only biopsy-based diagnostic methods are used.

METHODS

We compared histology, 13C-urea breath test (13C-UBT), and serology in H. pylori diagnostics in 50 male patients with atrophic corpus gastritis.

RESULTS

H. pylori was detected in 15 (30%) patients by histology and in 14 (28%) by 13C-UBT, whereas increased serum antibody levels indicating H. pylori infection were found in 41 (82%) patients (P < 0.0001 between serology and both histology and 13C-UBT). H. pylori infection was associated with atrophic corpus gastritis in 84% of the present patients (in one patient with normal antibody titres H. pylori was defined histologically).

CONCLUSIONS

H. pylori infection would have been missed in most patients with atrophic gastritis without the analysis of H. pylori antibodies. Therefore, in patients with atrophic gastritis, the use of serology is encouraged in diagnosing H. pylori infection.

Identification of hippurate-negative thermophilic campylobacters

Twenty-eight thermophilic campylobacter isolates showing negative hippurate hydrolysis were further characterized. Using Campylobacter jejuni and coli specific primers for ceuE gene, five of the isolates with repeatedly negative results in rapid hippurate hydrolysis were positive in C. jejuni-specific polymerase chain reaction (PCR) and 13 isolates were shown to be C. coli. All except one isolate with positive results in C. jejuni PCR were negative in C. coli PCR including those with repeatedly negative hippurate hydrolysis results. One isolate was positive in both PCRs due to a mixed culture. In comparison with PCR, API Campy gave concordant results in only 20 of the 28 isolates tested. Hybridization with PCR probes for ceuE gene of known C. jejuni and coli strains confirmed PCR results in all 27 isolates tested. In contrast to hippurate hydrolysis, PCR seemed to be a more reliable method to identify C. coli.

Helicobacter antibodies in Finnish centenarians

BACKGROUND

The prevalence of helicobacter antibodies increases with age and, in many developed countries, is highest in people born before 1940. Data on very old subjects are, however, limited. In this study we wanted to determine whether the age-related increase in the seroprevalence of H. pylori infection continues even in the oldest age group alive in Finland, the centenarians.

METHODS

Sera from 173 subjects (93% of all centenarians alive in Finland in 1991) were available for the present study. IgG and IgA antibodies against H. pylori were determined by an in-house enzyme immunoassay. To estimate the influence of atrophic gastritis on the prevalence of helicobacter antibodies, serum pepsinogen I (PG I) concentrations and parietal cell antibodies (PCAs) were measured by an enzyme immunoassay and indirect immunofluorescence, respectively.

RESULTS

The prevalence of helicobacter antibodies in Finnish centenarians was 66%. Low PG I values (<28 microg/l) were found in 36% and positive PCAs in 16% of the subjects studied. The prevalence of PCAs was especially high (50%) in H. pylori-negative subjects with low PG I values, suggesting severe gastric atrophy.

CONCLUSIONS

The age-related increase in H. pylori seroprevalence did not continue in the oldest age group alive in Finland. This may be explained partly by a relatively high frequency of atrophic gastritis (as suggested by low PG I values) in H. pylori-negative centenarians, but other factors--such as selective H. pylori-related mortality--may also have contributed to the fairly low seroprevalence (66%) observed.

In vitro adhesion and platelet aggregation properties of bacteremia-associated lactobacilli

Eight bacteremia-associated Lactobacillus strains were evaluated in vitro for the ability to adhere to human intestinal mucosa and to aggregate platelets. Adherence varied significantly among the strains, and platelet aggregation was induced by three strains. In conclusion, strong binding ability does not appear to be a prerequisite for the involvement of lactobacilli in bacteremia or to their ability to aggregate platelets.

Stability of related human and chicken Campylobacter jejuni genotypes after passage through chick intestine studied by pulsed-field gel electrophoresis

The genomic stability of 12 Campylobacter jejuni strains consisting of two groups of human and chicken isolates was studied by analysis of their PFGE (pulsed-field gel electrophoresis) patterns after passage through newly hatched chicks' intestines. The patterns of SmaI, SalI, and SacII digests remained stable after intestinal passage, except for those of two strains. One originally human strain, FB 6371, changed its genotype from II/A (SmaI/SacII) to I/B. Another strain, BTI, originally isolated from a chicken, changed its genotype from I/B to a new genotype. The genomic instability of the strains was further confirmed by SalI digestion and ribotyping of the HaeIII digests. In addition, heat-stable serotype 57 of strain FB 6371 changed to serotype 27 in all isolates with new genotypes but remained unchanged in an isolate with the original genotype. Serotype 27 of strain BTI remained stable. Our study suggests that during intestinal colonization, genomic rearrangement, as demonstrated by changed PFGE and ribopatterns, may occur.

Gastric inflammation is enhanced in children with CagA-positive Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection is likely to be acquired at an early age. The factors leading to active inflammation in childhood, however, are largely unknown.

SUBJECTS AND METHODS

We determined the CagA status, the best characterized virulence factor of H. pylori, and serum antibodies of IgG and IgA classes to H. pylori in 39 infected children.

RESULTS

Mononuclear cell infiltration in the antrum but not in the gastric body was more intense in CagA-positive children than in CagA-negative children. The degree of polymorphonuclear cell infiltration on the other hand was independent of the CagA status. The antibody titers of IgG and IgA classes to H. pylori were higher in CagA-positive than in CagA-negative infections (P<0.001 and P<0.01, respectively). IgG antibody titers to H. pylori correlated directly with the density of mononuclear and polymorphonuclear cell infiltration in the gastric antrum but not in the gastric body.

CONCLUSION

H. pylori-infected children with CagA antibodies seem to have a more severe inflammation in the gastric antrum than CagA-negative children as shown by an increase in the density of antral mononuclear cells. A finding of higher serum antibody titers to H. pylori in CagA-positive children may be related to this enhancement of inflammation.

Helicobacter pylori-positive gastritis in pediatric patients with chronic inflammatory bowel disease

BACKGROUND

Gastritis is a common finding in patients with inflammatory bowel disease. However, the association of gastritis with Helicobacter pylori is unclear in these patients.

METHODS

The prevalence of antibodies for H. pylori in serum was determined in 47 pediatric patients with inflammatory bowel disease (19 with Crohn's disease, 21 with ulcerative colitis, and 7 with unclassified disease). H. pylori antibodies of the IgG and IgA classes were measured by enzyme immunoassay in 24 patients at the time of diagnosis of inflammatory bowel disease and in 23 more patients during the follow-up of inflammatory bowel disease (mean follow-up, 3.5 years; range 1-10 years). Esophagogastroduodenoscopy was performed on 40 patients during the examination for inflammatory bowel disease.

RESULTS

In contrast to earlier findings, no patient was determined to be positive for H. pylori, either in serologic or histologic examination. This negative finding was unexpected, because it is known that approximately 10% of asymptomatic Finnish children have antibodies for H. pylori in serum and approximately 10% of analyses of specimens obtained in gastric antral biopsies obtained at the Hospital for Children and Adolescents, Helsinki, Finland, are positive for H. pylori.

CONCLUSIONS

Permanent colonization of the stomach with H. pylori is unusual in children with inflammatory bowel disease.

Persisting Helicobacter antibodies in Finnish children and adolescents between two and twenty years of age

BACKGROUND

Helicobacter pylori is an important gastric pathogen usually acquired in childhood. The presumed lifelong progression of H. pylori infection has recently been called into question in some longitudinal studies on children. In this follow-up study the prevalence and persistence of H. pylori antibodies in Finnish children and adolescents from three communities was determined.

METHODS

We measured H. pylori antibodies in follow-up serum samples of 337 Finnish children who participated in a measles-mumps-rubella vaccine study started in 1982. All available samples collected in 1983, 1987 and 1995 were studied first; additional serum samples collected yearly were studied from children who became seropositive during the follow-up period.

RESULTS

The overall prevalence of H. pylori antibodies was 5.6%. About two-thirds of the Helicobacter infections were acquired before the age of 7 years; of the remaining one-third the time of seroconversion varied between 7 and 19 years. No seroreverters were found. There were no statistically significant differences in the seroprevalence of H. pylori antibodies in the three communities studied.

CONCLUSIONS

The prevalence of H. pylori antibodies in Finnish children studied was low. Although the majority of new infections were found in children younger than 7 years of age, new Helicobacter infections were acquired throughout childhood and adolescence. Once acquired H. pylori infection, as verified by Helicobacter antibodies, persisted.

Positive result by serology indicates active Helicobacter pylori infection in patients with atrophic gastritis

Patients with atrophic corpus gastritis and elevated Helicobacter pylori antibody titers but 13C-urea breath test (13C-UBT) and histology results negative for H. pylori were randomized into eradication therapy or follow-up only. Antibody levels decreased significantly in six out of seven patients in the eradication group, while in the follow-up group, the titers declined in only one out of eight patients. In patients with atrophic corpus gastritis, positive serology results may indicate an ongoing infection in spite of negative 13C-UBT and histology results.

Typing of human Campylobacter jejuni isolates in Finland by pulsed-field gel electrophoresis

A total of 69 pulsed-field gel electrophoresis (PFGE) types were identified among 176 Campylobacter jejuni isolates from Finnish patients. In two geographic areas studied, five predominant PFGE types comprised over 40% of the isolates. One-third of the isolates had unique PFGE types. In small outbreaks, identical PFGE patterns were demonstrated, indicating a common source of infection.

Evaluation of Pyloriset Screen, a rapid whole-blood diagnostic test for Helicobacter pylori infection

Helicobacter pylori infection can be detected by several invasive tests based on gastroscopy and by noninvasive methods such as serologic assays. Noninvasive tests can be used not only in addition to invasive tests but also by themselves to screen for H. pylori infection in patients who are not in urgent need of endoscopy. Lately, rapid qualitative serologic tests have been developed. In the present study, the accuracy of a novel rapid whole-blood test, Pyloriset Screen, detecting immunoglobulin G (IgG) and IgA antibodies against H. pylori was evaluated. A total of 207 consecutive adult outpatients referred for upper endoscopy were enrolled. Gastric biopsy specimens were taken from the antrum and corpus for histologic examination and rapid urease testing. Cultures were available for 113 patients. Serum samples collected from all patients were tested for H. pylori antibodies by two enzyme immunoassays (EIAs) (Pyloriset EIA and an in-house EIA), a rapid latex agglutination test (Pyloriset Dry), and Pyloriset Screen. Patients were considered H. pylori positive if helicobacters were seen on histologic examination (77 patients) or, if in combination with histologically verified (although helicobacter-negative) gastritis, their IgG antibody titers were elevated in the two EIAs (five patients). The Pyloriset Screen test had a sensitivity of 95%, a specificity of 94%, a positive predictive value of 91%, and a negative predictive value of 97%. Among 63 patients under the age of 45 years, the Pyloriset Screen test did not miss a single H. pylori diagnosis, and only 1 patient had a false-positive result. Pyloriset Screen could be used reliably to screen for H. pylori infection.