Multiplex PCR assay for differentiation of Helicobacter felis, H. bizzozeronii, and H. salomonis

[Detection of Helicobacter species in humans and their dog]

Helicobacter is a genus of Gram-negative bacteria that colonizes the stomach of humans and dogs, among other mammals. The most frequent species found in the gastric mucosa of man is H. pylori, however, there are other species of Helicobacter in the stomach of humans, such as H. suis, H. bizzozeronii, H. felis, H. salomonis and H. heilmannii sensu stricto, named non H. pylori Helicobacter (NHPH) some of which also colonize the dog's stomach. The detection of NHPH in the stomach mucosa of humans with gastric disease, and in a high percentage of dogs, suggests the possibility that these animals play an important role in the pathogenesis and transmission of infection to man, postulating the path of transmission oral-oral or fecal-oral. The aim of this study was to determine whether people with signs of chronic gastritis who have Helicobacter spp. and who own dogs as pets, share the same species with them. The presence of Helicobacter spp. in gastric samples of 30 people with clinical signs of chronic gastritis and histopathological diagnosis of gastric infection with Helicobacter spp. was analyzed by PCR. The presence of Helicobacter spp. was also studied in the dogs of these people. Then, the species of Helicobacter presented was determined in both. In human gastric samples, H. pylori was the only species found, while in dogs, samples were H. bizzozeronii, H. felis, H. salomonis and H. heilmannii. In this work the same species were not found in dogs and their owners.

Helicobacter Species and Their Association with Gastric Pathology in a Cohort of Dogs with Chronic Gastrointestinal Signs

Prevalence of individual Helicobacter species, data evaluating their association with gastric pathology and comparison of accuracy of diagnostic techniques are limited. The aims of this study were to determine the prevalence of gastric Helicobacter species, their association with gastric pathology, and to compare diagnostic techniques. Gastric biopsies from 84 privately-owned dogs with chronic gastrointestinal signs were obtained endoscopically. Helicobacters were detected using PCR, cytology, urease test, and histopathology. PCR detected helicobacters in 71.4% of dogs. Helicobacter heilmannii sensu stricto (s.s.) was the predominant species. Mixed infection was detected in 40% of PCR positive dogs. Gastritis was diagnosed in 38.5% of Helicobacter positive and 47.4% of Helicobacter negative dogs. Mono-infection was associated with 2.4 times increased odds of having more severe inflammation compared to mixed infection. Erosions and ulcers were common endoscopic lesions. Cytology had sensitivity/specificity of 88.3/91.7%. Association between infection and lymphoid follicular hyperplasia was demonstrated.

Helicobacter species binding to the human gastric mucosa

Helicobacter pylori infects half of the world population, being associated with several gastric disorders, such as chronic gastritis and gastric carcinoma. The Helicobacter genus also includes other gastric helicobacters, such as H. heilmannii¸ H. ailurogastricus, H. suis, H. felis, H. bizzozeronii, and H. salomonis. These gastric helicobacters colonize both the human and animal stomach. The prevalence of gastric non-Helicobacter pylori Helicobacter (NHPH) species in humans has been described as low, and the in vitro binding to the human gastric mucosa was never assessed. Herein, human gastric tissue sections were used for the evaluation of the tissue glycophenotype and for the binding of gastric NHPH strains belonging to different species. Histopathological evaluation showed that 37.5% of the patients enrolled in our cohort presented chronic gastritis, while the presence of neutrophil or eosinophilic activity (chronic active gastritis) was observed in 62.5% of the patients. The secretor phenotype was observed in 68.8% of the individuals, based on the expression of Lewis B antigen and binding of the UleX lectin. The in vitro binding assay showed that all the NHPH strains evaluated were able to bind, albeit in low frequency, to the human gastric mucosa. The H. heilmannii, H. bizzozeronii, and H. salomonis strains displayed the highest binding ability both to the gastric superficial epithelium and to the deep glands. Interestingly, we observed binding of NHPH to the gastric mucosa of individuals with severe chronic inflammation and intestinal metaplasia, suggesting that NHPH binding may not be restricted to the healthy gastric mucosa or slight chronic gastritis. Furthermore, the in vitro binding of NHPH strains was observed both in secretor and non-secretor individuals in a similar frequency. In conclusion, this study is the first report of the in vitro binding ability of gastric NHPH species to the human gastric mucosa. The results suggest that other glycans, besides the Lewis antigens, could be involved in the bacterial adhesion mechanism; however, the molecular intervenients remain unknown.

Antimicrobial Susceptibility Pattern of Helicobacter heilmannii and Helicobacter ailurogastricus Isolates

A combined agar and broth dilution method followed by qPCR was used to determine the antimicrobial susceptibility of feline H. heilmannii and H. ailurogastricus isolates. All H. ailurogastricus isolates showed a monomodal distribution of MICs for all the antimicrobial agents tested. For H. heilmannii, a bimodal distribution was observed for azithromycin, enrofloxacin, spectinomycin, and lincomycin. Single nucleotide polymorphisms (SNPs) were found in 50S ribosomal proteins L2 and L3 of the H. heilmannii isolate not belonging to the WT population for azithromycin, and in 30S ribosomal proteins S1, S7, and S12 of the isolate not belonging to the WT population for spectinomycin. The antimicrobial resistance mechanism to enrofloxacin and lincomycin remains unknown (2 and 1 H. heilmannii isolate(s), resp.). Furthermore, H. heilmannii isolates showed higher MICs for neomycin compared to H. ailurogastricus isolates which may be related to the presence of SNPs in several 30S and 50S ribosomal protein encoding genes and ribosomal RNA methyltransferase genes. This study shows that acquired resistance to azithromycin, spectinomycin, enrofloxacin, and lincomycin occasionally occurs in feline H. heilmannii isolates. As pets may constitute a source of infection for humans, this should be kept in mind when dealing with a human patient infected with H. heilmannii.

Presence of gastric Helicobacter species in children suffering from gastric disorders in Southern Turkey

BACKGROUND

Infections with gastric Helicobacter spp. are associated with gastritis, peptic ulceration, and malignancies. Helicobacter pylori is the most prevalent Helicobacter species colonizing the human stomach. Other gastric non-H. pylori helicobacters (NHPHs) have been described in 0.2%-6% of human patients with gastric disorders. Nevertheless, due to difficulties in the diagnosis of NHPH infections and lack of routine screening, this is most likely an underestimation of their true prevalence. To the best of our knowledge, no studies have been performed in the presence of Helicobacter spp. in children suffering from gastric disorders in Southern Turkey.

MATERIALS AND METHODS

In total, 110 children with gastric complaints were examined at the Cukurova University Balcali hospital, Turkey. Gastroscopy was performed to evaluate the presence of gastric mucosal lesions. Biopsies of the pyloric gland zone were taken for histopathological analysis, rapid urease testing, and presence of Helicobacter spp. DNA by PCR.

RESULTS

Based on the PCR results, the prevalence of Helicobacter spp. was 32.7% (36/110). H. pylori was found in 30.9% (34/110), H. suis in 1.8% (2/110), and H. heilmannii/H. ailurogastricus in 0.9% (1/110) of the human patients. A mixed infection with H. pylori and H. suis was present in one patient. The presence of mucosal abnormalities, such as nodular inflammation, ulceration, and hyperemia, as well as gastritis, was significantly higher in Helicobacter spp. positive patients.

CONCLUSION

Helicobacter pylori, H. suis, and H. heilmannii/H. ailurogastricus were present in children with gastric complaints. Infection with these pathogens may be involved in the development of gastritis and ulceration.

Detection of Helicobacter spp. in the saliva of dogs with gastritis

The aim of this study was to identify the species and determine the prevalence of gastric Helicobacter in the saliva of dogs with gastritis. The study was carried out on 30 dogs of different breeds, genders and ages, which were diagnosed with gastritis. The nested-PCR method was used to detect Helicobacter spp. in saliva. Helicobacter bacteria were found in the saliva samples of 23 (76.6%) dogs. Helicobacter heilmannii was the most commonly detected species of gastric Helicobacter spp. in canine saliva, and was found in 22 (73.3%) cases. The results indicate that gastric Helicobacter spp. occurs relatively frequently in dogs with gastritis. Moreover, the saliva of dogs with gastritis may be a source of Helicobacter spp. infection for humans and other animals. However, further studies are needed to confirm this finding as the PCR method does not distinguish active from inactive infections.

Frequency of virulence genes in mixed infections with Helicobacter pylori strains from a Mexican population

BACKGROUND

Helicobacter pylori (H. pylori) is associated with gastroduodenal diseases. Virulence of clinical isolates is related to clinical outcome. Moreover, with microdiversity studies in clinical isolates from a single patient, but from a different origin (antrum or corpus), it is possible to demonstrate that there are simultaneous mixed infections.

AIMS

To genotype H. pylori strains with multiplex PCR, according to their clinical virulence, and in this manner know the frequency of each genotype and relate it to clinical outcome in order to prevent the development of severe diseases.

METHODS

A total of 210 patients with gastric alterations were studied. Virulence classification of H. pylori strains was carried out with multiplex PCR and 127 strains were identified as H. pylori by PCR (glmM and cagE). Genotype and clinical outcome were evaluated with the Fisher's exact test. In addition, RAPD-PCR was performed as a fingerprinting method to analyze mixed infections.

RESULTS

The cagA, vacAs1, and vacAm1 genes were detected in all the clinical isolates. Strains were classified as: type i, 40.15% (51/127); type ii, 22.04% (28/127); and type iii, 28.4% (36/127), but two new different genotypes were also detected: (1) babA2+, cagA+, vacAs1+, 6.29% (8/127) and (2) babA2+, cagA-, vacAs2/m2+, 3.14% (4/127). The cagE gene was detected in type i strains.

CONCLUSIONS

The Fisher's exact test did not support a significant association between clinical outcome and genotype. The main circulating genotypes in the Mexican population studied were: cagA+, vacAs1, and vacAm1. Multiplex PCR can be used as a screening test for H. pylori strains. Furthermore, the cagE gene is a good marker for identifying cag-PAI positive strains.

Non-protein coding RNA genes as the novel diagnostic markers for the discrimination of Salmonella species using PCR

Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.

Helicobacter heilmannii sensu lato: An overview of the infection in humans

Helicobacter heilmannii sensu lato (H. heilmannii s.l.) is a group of gastric non-Helicobacter pylori Helicobacter species that are morphologically indistinguishable from each other. H. heilmannii s.l. infect the stomach of several animals and may have zoonotic potential. Although the prevalence of these infections in humans is low, they are associated with gastric pathology, including mucosa-associated lymphoid tissue lymphoma, making them a significant health issue. Here, the taxonomy, epidemiology, microbiology, diagnosis, and treatment of these infections will be reviewed. The gastric pathology associated with H. heilmannii s.l. infections in humans will also be addressed. Finally, the features of the complete bacterial genomes available and studies on species-specific pathogenesis will be reviewed. The understanding of the mechanisms that underlie gastric disease development mediated by the different bacterial species that constitute H. heilmannii s.l. is essential for developing strategies for prevention and treatment of these infections.

Anti-CXCL13 antibody can inhibit the formation of gastric lymphoid follicles induced by Helicobacter infection

Helicobacter suis infects the stomachs of both animals and humans, and can induce gastric mucosa-associated lymphoid tissue (MALT) lymphomas. It is known that CXC chemokine ligand 13 (CXCL13) is highly expressed in the Helicobacter-infected mice and gastric MALT lymphoma patients, but the pathway that links the activation of CXCL13 and the formation of gastric MALT lymphomas remains unclear. In this study, we examined whether CXCL13 neutralization would interfere with the formation of gastric lymphoid follicles including B cells, CD4+T cells, dendritic cells (DCs), and follicular DCs (FDCs) in germinal centers to determine the role of CXCL13 in the formation of B-cell aggregates after H. suis infection. Moreover, the expression of genes associated with the lymphoid follicle formation was also effectively suppressed by anti-CXCL13 antibody treatment. These results suggest that the upregulation of CXCL13 has an important role in the development of gastric MALT lymphomas and highlight the potential of anti-CXCL13 antibody for protection against Helicobacter-induced gastric diseases.

Development of new PCR primers by comparative genomics for the detection of Helicobacter suis in gastric biopsy specimens

BACKGROUND

Although the infection rate of Helicobacter suis is significantly lower than that of Helicobacter pylori, the H. suis infection is associated with a high rate of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. In addition, in vitro cultivation of H. suis remains difficult, and some H. suis-infected patients show negative results on the urea breath test (UBT).

MATERIALS AND METHODS

Female C57BL/6J mice were orally inoculated with mouse gastric mucosal homogenates containing H. suis strains TKY or SNTW101 isolated from a cynomolgus monkey or a patient suffering from nodular gastritis, respectively. The high-purity chromosomal DNA samples of H. suis strains TKY and SNTW101 were prepared from the infected mouse gastric mucosa. The SOLiD sequencing of two H. suis genomes enabled comparative genomics of 20 Helicobacter and 11 Campylobacter strains for the identification of the H. suis-specific nucleotide sequences.

RESULTS

Oral inoculation with mouse gastric mucosal homogenates containing H. suis strains TKY and SNTW101 induced gastric MALT lymphoma and the formation of gastric lymphoid follicles, respectively, in C57BL/6J mice. Two conserved nucleotide sequences among six H. suis strains were identified and were used to design diagnostic PCR primers for the detection of H. suis.

CONCLUSIONS

There was a strong association between the H. suis infection and gastric diseases in the C57BL/6 mouse model. PCR diagnosis using an H. suis-specific primer pair is a valuable method for detecting H. suis in gastric biopsy specimens.

Detection of Helicobacter spp. DNA in the colonic biopsies of stray dogs: molecular and histopathological investigations

Abstract

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1957989294118782.

Differentiation of non-pylori Helicobacter species based on PCR-restriction fragment length polymorphism of the 23S rRNA gene

Phenotypic identification of non-pylori Helicobacter species has always been problematic and time-consuming in comparison with many other bacteria. We developed a rapid two-step identification assay based on PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 23S rRNA gene for differentiating between non-pylori Helicobacter species. A new genus-specific primer pair based on all available complete and partial 23S rRNA sequences of Helicobacter species was designed. In silico restriction analysis of variable regions of the 23S rRNA gene suggested SmaI and HindIII endonucleases would provide a good level of differentiation. Analysis of the obtained 23S rRNA RFLP patterns divided all Helicobacter study strains into three species groups (groups A-C) and 12 unique restriction patterns. Wolinella succinogenes also gave a unique pattern. Our proposed PCR-RFLP method was found to be as a valuable tool for routine identification of non-pylori Helicobacter species from human or animal samples.

A multiplex PCR for the simultaneous detection and genotyping of the Echinococcus granulosus complex

Echinococcus granulosus is characterized by high intra-specific variability (genotypes G1–G10) and according to the new molecular phylogeny of the genus Echinococcus, the E. granulosus complex has been divided into E. granulosus sensu stricto (G1–G3), E. equinus (G4), E. ortleppi (G5), and E. canadensis (G6–G10). The molecular characterization of E. granulosus isolates is fundamental to understand the spatio-temporal epidemiology of this complex in many endemic areas with the simultaneous occurrence of different Echinococcus species and genotypes. To simplify the genotyping of the E. granulosus complex we developed a single-tube multiplex PCR (mPCR) allowing three levels of discrimination: (i) Echinococcus genus, (ii) E. granulosus complex in common, and (iii) the specific genotype within the E. granulosus complex. The methodology was established with known DNA samples of the different strains/genotypes, confirmed on 42 already genotyped samples (Spain: 22 and Bulgaria: 20) and then successfully applied on 153 unknown samples (Tunisia: 114, Algeria: 26 and Argentina: 13). The sensitivity threshold of the mPCR was found to be 5 ng Echinoccoccus DNA in a mixture of up to 1 µg of foreign DNA and the specificity was 100% when template DNA from closely related members of the genus Taenia was used. Additionally to DNA samples, the mPCR can be carried out directly on boiled hydatid fluid or on alkaline-lysed frozen or fixed protoscoleces, thus avoiding classical DNA extractions. However, when using Echinococcus eggs obtained from fecal samples of infected dogs, the sensitivity of the mPCR was low (<40%). Thus, except for copro analysis, the mPCR described here has a high potential for a worldwide application in large-scale molecular epidemiological studies on the Echinococcus genus.

The dog tapeworm Echinococcus granulosus (E. granulosus) is a cosmopolitan parasite. The adult worms reside in the small intestine of their definitive hosts (dogs). Infective eggs are shed with the feces into the environment and are orally ingested by intermediate hosts where they develop into the metacestode (larval) stage, causing cystic echinococcosis (CE) in humans and livestock. Ten intraspecific genotypes of E. granulosus (G1 to G10) have been reported from different intermediate host species. Based on the recently established molecular phylogeny, E. granulosus is now considered a complex consisting of four species: E. granulosus sensu stricto (G1/G2/G3), E. equinus (G4), E. ortleppi (G5) and E. canadensis (G6–G10). Simple and highly discriminative molecular epidemiological approaches are needed to explore dynamics, life cycle patterns, and the pathogenicity of the members of this complex. We here introduce a one-step multiplex PCR (mPCR) protocol for the genotyping and discrimination of the different members of the E. granulosus complex, allowing three levels of discrimination: (i) Echinococcus genus, (ii) E. granulosus complex, and (iii) genetic variants within the E. granulosus complex. The relatively complicated task of E. granulosus complex speciation and genotyping is clearly simplified by mPCR, and this technique therefore represents a useful tool for routine practice.

High prevalence of dna from non-H. pylori helicobacters in the gastric mucosa of venezuelan pet dogs and its histological alterations

Non-H. pylori helicobacters (NHPH) have been demonstrated as gastric spiral-shaped bacteria in specimens obtained from dogs; however, their roles in the pathogenesis of upper gastrointestinal disease have not yet been clearly established. The purpose of this study was to evaluate the prevalence of NHPH DNA in the gastric mucosa of dogs and its association with histopathology. Helicobacter was detected through histopathological techniques, PCR, and FISH analysis from fundic biopsies of twenty dogs with or without signs of gastrointestinal disease. PCR and FISH were based on partial 16S rRNA gene sequences. Nineteen dogs showed mild to marked gastritis in the fundus, and only one dog had a healthy gastric mucosa. NHPH DNA was detected in 18 dogs with gastritis and one with normal gastric mucosa. However, there was no significant correlation between the presence of NHPH DNA and the degree of gastritis. These results show a high prevalence of NHPH DNA in the gastric mucosa of dogs from Venezuela. Further studies are necessary to determine a possible association between a specific NHPH species and the degree of gastritis.

Gastric helicobacters in domestic animals and nonhuman primates and their significance for human health

Helicobacters other than Helicobacter pylori have been associated with gastritis, gastric ulcers, and gastric mucosa-associated lymphoid tissue lymphoma in humans. These very fastidious microorganisms with a typical large spiral-shaped morphology were provisionally designated "H. heilmannii," but in fact they comprise at least five different Helicobacter species, all of which are known to colonize the gastric mucosa of animals. H. suis, which has been isolated from the stomachs of pigs, is the most prevalent gastric non-H. pylori Helicobacter species in humans. Other gastric non-H. pylori helicobacters colonizing the human stomach are H. felis, H. salomonis, H. bizzozeronii, and the still-uncultivable "Candidatus Helicobacter heilmannii." These microorganisms are often detected in the stomachs of dogs and cats. "Candidatus Helicobacter bovis" is highly prevalent in the abomasums of cattle but has only occasionally been detected in the stomachs of humans. There are clear indications that gastric non-H. pylori Helicobacter infections in humans originate from animals, and it is likely that transmission to humans occurs through direct contact. Little is known about the virulence factors of these microorganisms. The recent successes with in vitro isolation of non-H. pylori helicobacters from domestic animals open new perspectives for studying these microorganisms and their interactions with the host.

Non-Helicobacter pylori helicobacters detected in the stomach of humans comprise several naturally occurring Helicobacter species in animals

Besides the well-known gastric pathogen Helicobacter pylori, other Helicobacter species with a spiral morphology have been detected in a minority of human patients who have undergone gastroscopy. The very fastidious nature of these non-Helicobacter pylori helicobacters (NHPH) makes their in vitro isolation difficult. These organisms have been designated 'Helicobacter heilmannii'. However, sequencing of several genes detected in NHPH-infected tissues has shown that the 'H. heilmannii' group comprises at least five different Helicobacter species, all of them known to colonize the stomach of animals. Recent investigations have indicated that Helicobacter suis is the most prevalent NHPH species in human. This species has only recently been isolated in vitro from porcine stomach mucosa. Other NHPH that colonize the human stomach are Helicobacter felis, Helicobacter bizzozeronii, Helicobacter salomonis and 'Candidatus Helicobacter heilmannii'. In numerous case reports of human gastric NHPH infections, no substantial information is available about the species status of the infecting strain, making it difficult to link the species with certain pathologies. This review aims to clarify the complex nomenclature of NHPH species associated with human gastric disease and their possible animal origin. It is proposed to use the term 'gastric NHPH' to designate gastric spirals that are morphologically different from H. pylori when no identification is available at the species level. Species designations should be reserved for those situations in which the species is defined.

Isolation and characterization of Helicobacter suis sp. nov. from pig stomachs

A new cultivation method was successfully applied for the in vitro isolation of a hitherto uncultured spiral Helicobacter species associated with ulceration of the non-glandular stomach and gastritis in pigs and formerly described as 'Candidatus Helicobacter suis'. Three isolates, HS1(T), HS2 and HS3, were subcultured from the stomach mucosa of three pigs after slaughter and were analysed using a polyphasic taxonomic approach. The novel isolates grew on biphasic culture plates or very moist agar bases in microaerobic conditions and exhibited urease, oxidase and catalase activities. Sequencing of the 16S rRNA gene, the 23S rRNA gene, the partial hsp60 gene and partial ureAB genes confirmed that the strains present in the gastric mucosa of pigs constituted a separate taxon, corresponding to 'Helicobacter heilmannii' type 1 strains as detected in the gastric mucosa of humans and other primates. For all genes sequenced, the highest sequence similarities were obtained with Helicobacter felis, Helicobacter bizzozeronii and Helicobacter salomonis, Helicobacter species isolated from the gastric mucosa of dogs and cats, which have also been detected in the human gastric mucosa and which are commonly referred to as 'Helicobacter heilmannii' type 2. SDS-PAGE of whole-cell proteins of strains HS1(T), HS2 and HS3 differentiated them from other Helicobacter species of gastric origin. The results of the polyphasic taxonomic analysis confirmed that the novel isolates constitute a novel taxon corresponding to 'Helicobacter heilmannii' type 1 strains from humans and to 'Candidatus H. suis' from pigs. The name Helicobacter suis sp. nov. is proposed for the novel isolates with the type strain HS1(T) (=LMG 23995(T)=DSM 19735(T)).

Evaluation of 16S rRNA gene-based PCR assays for genus-level identification of Helicobacter species

The inclusivity, exclusivity, and detection limit of six 16S rRNA gene-based Helicobacter genus-specific PCR assays were examined. Five out of six assays were 100% inclusive, but the tests varied considerably in their exclusivity (9.1 to 95.5%). The clinical detection limit varied between 10(3) and 1 viable bacterial cell per reaction mixture.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

Peptic ulcer disease associated with Helicobacter felis in a dog owner

The aim of this study was to investigate the identity of the Helicobacter heilmannii-like bacteria found in the stomach of a human patient suffering from stomach ulcers and her asymptomatic pet dog. An elderly woman was referred for gastroscopy because of right hypochondrial pain, nausea, anorexia and vomiting. Gastric ulcers were observed and histology revealed the presence of multiple H. heilmannii-like bacteria. Multiplex polymerase chain reaction (PCR) identified the bacteria as H. felis. Her pet dog was also examined gastroscopically. Only mild gastric lesions were found but PCR showed the presence of H. felis as well as H. bizzozeronii and Candidatus H. heilmannii. This report associates H. felis infection in humans with severe gastric ulceration. Moreover, the suggestion can be made that the patient contracted H. felis from her dog.

Prevalence of Helicobacter equorum in faecal samples from horses and humans

Recently, a new enterohepatic Helicobacter species, H. equorum, was isolated from faecal samples of two clinically healthy horses. At the onset of this study, nothing was known about the prevalence of this organism in horses, nor was there any information available on the possible zoonotic character of this agent. This study aimed to determine the prevalence of H. equorum in faecal samples from equine and human origin. Therefore, faecal samples of 120 healthy privately owned horses, 227 healthy riding-school horses and 239 hospitalised horses were screened for H. equorum-DNA by means of a PCR amplifying a 1074-bp fragment of the 23S rRNA gene with primers specific for H. equorum. The vast majority of the hospitalised horses were under treatment with an antimicrobial agent at the moment of sampling, while the other horses had not been treated with an antimicrobial agent in the 14 days preceding the sampling. Stool samples of 531 humans suffering from gastro-intestinal disease and 100 clinically healthy humans were likewise examined. H. equorum-DNA was demonstrated in faeces from 0.8% of the privately owned horses, 3.1% of the riding-school horses and 7.9% of the hospitalised horses. The prevalence of H. equorum was significantly higher in hospitalised than in healthy, privately owned horses (P=0.02). H. equorum-DNA was not detected in human samples. These results indicate that the prevalence of H. equorum in horses may be influenced by the health status of the investigated horse population and/or by antimicrobial treatment. We may additionally assume that this micro-organism does not commonly infect humans.

The effect of Helicobacter felis and Helicobacter bizzozeronii on the gastric mucosa in Mongolian gerbils: a sequential pathological study

In contrast to Helicobacter(H.) pylori, little is known about the pathogenic mechanisms of gastric non-H. pylori Helicobacter species. Mongolian gerbils were inoculated intragastrically with H. felis or H. bizzozeronii and killed at different timepoints post-inoculation (p.i.), stomach tissue being taken for light and transmission electron microscopy (TEM) and polymerase chain reaction (PCR) analysis. Parietal cells (PCs), apoptosis, cell proliferation and nuclear factor-kappaB (NF-kappaB) activation were "visualized" immunohistochemically. Inflammation consisted of neutrophilic granulocytes, mainly in the antrum, and lymphocytic infiltrates around the limiting ridge and throughout the stomach mucosa and submucosa. From day 11 p.i. onwards, H. felis-inoculated animals showed moderate to severe loss of PCs extending from the limiting ridge into the fundus. Apoptotic cells, spiral bacteria, cell proliferation, and NF-kappaB activation were detected at the transition zone between affected and normal PCs. TEM revealed interaction of H. felis flagella with PCs and chief cells. Moreover, H. felis was seen in proximity to, and inside, necrotic cells. At 10 weeks p.i., some H. felis-infected gerbils showed complete loss of fundic glands, and mucous metaplasia of the epithelium. H. bizzozeronii, which made no flagellar contact with epithelial cells, was associated with only mild PC loss. The mechanism by which H. felis induces PC necrosis and apoptosis remains unclear. The observed flagellar contact and NF-kappaB activation may play an important role in H. felis-associated inflammation.

Helicobacter cynogastricus sp. nov., isolated from the canine gastric mucosa

A Gram-negative, microaerophilic helical rod, isolated from the gastric mucosa of a dog and designated strain JKM4(T), was subjected to a polyphasic taxonomic study. The tightly coiled organism, measuring 10-18 mum long and up to 1 mum wide, was motile by means of multiple sheathed flagella located at both ends of the cell and by a periplasmic fibril running along the external side of the helix. Strain JKM4(T) grew preferably on biphasic culture plates or on very moist agar. Coccoid forms predominated in cultures older than 4 days as well as in growth obtained on dry agar plates. The strain grew at 30 and 37 degrees C, but not at 25 or 42 degrees C and exhibited urease, oxidase and catalase activities. On the basis of 16S rRNA gene sequence analysis, the novel isolate was identified as a member of the genus Helicobacter and showed > 97 % similarity to Helicobacter felis, Helicobacter bizzozeronii and Helicobacter salomonis, three species previously isolated from the canine gastric mucosa. Protein profiling of strain JKM4(T) using SDS-PAGE revealed a pattern different from those of other Helicobacter species of mammalian gastric origin and from Helicobacter canis. Additionally, the urease gene sequence of strain JKM4(T) was different from those of urease genes of H. felis, H. bizzozeronii, H. salomonis and "Candidatus Helicobacter heilmannii". It is thus proposed that strain JKM4(T) (=LMG 23188(T)) represents a novel species within this genus, Helicobacter cynogastricus sp. nov.

In vivo selection of reduced enrofloxacin susceptibility in Ornithobacterium rhinotracheale and its resistance-related mutations in gyrA

This study determines the genetic background of the change in antimicrobial susceptibility to enrofloxacin of Ornithobacterium rhinotracheale (ORT) isolates with increased MIC values, isolated either from the field or from turkeys treated with enrofloxacin under experimental challenge conditions. In the field strains of ORT that were either less susceptible or, occasionally, resistant to enrofloxacin, point mutations had occurred in amino acids at positions 83 (serine) or 87 (aspartic acid) of the GyrA subunit. In the isolates showing reduced susceptibility following experimental enrofloxacin treatment (increase in MIC from < or =0.03 to 0.25 microg/ml), molecular analysis revealed a constantly recurring point mutation (G-->T) at nucleic acid position 646 (E. coli numbering) of gyrA resulting in an amino acid change from aspartic acid to tyrosine at position 87 of the GyrA subunit, which is a known hot spot for fluoroquinolone resistance. This study indicates that a single course of enrofloxacin treatment may contribute to the selection of the first mutant with reduced fluoroquinolone susceptibility in ORT. Acquired fluoroquinolone resistance is commonly encountered in ORT isolates. This is the first time that the causal mechanism of fluoroquinolone resistance in ORT has been investigated.

Capillary electrophoresis and the clinical laboratory

Over the past 15 years, CE as an analytical tool has shown great promise in replacing many conventional clinical laboratory methods, such as electrophoresis and HPLC. CE's appeal was that it was fast, used very small amounts of sample and reagents, was extremely versatile, and was able to separate large and small analytes, whether neutral or charged. Because of this versatility, numerous methods have been developed for analytes that are of clinical interest. Other than molecular diagnostic and forensic laboratories CE has not been able to make a major impact in the United States. In contrast, in Europe and Japan an increasing number of clinical laboratories are using CE. Now that automated multicapillary instruments are commercially available along with cost-effective test kits, CE may yet be accepted as an instrument that will be routinely used in the clinical laboratories. This review will focus on areas where CE has the potential to have the greatest impact on the clinical laboratory. These include analyses of proteins found in serum and urine, hemoglobin (A1c and variants), carbohydrate-deficient transferrin, forensic and therapeutic drug screening, and molecular diagnostics.

The inflammatory response in the mouse stomach to Helicobacter bizzozeronii, Helicobacter salomonis and two Helicobacter felis Strains

The inflammatory response in the mouse stomach was evaluated as a means of distinguishing different non-pylori Helicobacter (H.) strains in terms of virulence. Mice of four strains (BALB/c, SJL, C57BL/6 and CFW) were infected intragastrically with four bacterial strains (H. felis ATCC 49179 and CCUG 37471, H. bizzozeronii and H. salomonis). The animals were killed for gastric examination at 3, 9 or 16 weeks post-inoculation. H. salomonis could not be detected by the polymerase chain reaction, but the other three organisms were detected in all stomach samples at all timepoints. SJL mice consistently showed particularly severe gastric inflammation regardless of bacterial strain. Lymphocytes and occasionally neutrophils were seen in submucosa and lamina propria mucosae. BALB/c mice showed the least severe inflammatory changes. H. bizzozeronii differed from the two H. felis strains in producing less striking pathological changes in mice. Of the two H. felis strains, ATCC 49179 produced the more severe inflammatory changes in SJL mice.

Helicobacter felis and Helicobacter bizzozeronii induce gastric parietal cell loss in Mongolian gerbils

Non-pylori helicobacter infections are associated with gastritis, gastric ulcers and MALT lymphomas in man. Approximately 50% of these are caused by helicobacters commonly found in dogs and cats, including Helicobacter felis, Helicobacter bizzozeronii and H. salomonis. In contrast to Helicobacter pylori, the virulence mechanisms of these species are unknown. In this study the virulence of H. felis, H. bizzozeronii and H. salomonis was investigated in Mongolian gerbils. Female SPF gerbils were inoculated intragastrically with H. felis, H. bizzozeronii or H. salomonis and sacrificed 3 weeks later. Fundus and antrum samples were taken for bacterial detection by PCR. A longitudinal strip covering all stomach regions was taken for histology. Gastric colonization, inflammation, apoptosis, loss of parietal cells and cell proliferation were assessed. Controls and H. salomonis inoculated gerbils were negative in PCR. H. felis and H. bizzozeronii inoculated animals were positive. H. felis inoculated animals showed loss of parietal cells extending from the limiting ridge into the fundus. A high cell proliferation rate was noticed in the mucosal area devoid of parietal cells. A dense band of apoptotic cells and large numbers of Helicobacter bacteria were seen at the transition zone between affected and normal parietal cells. In H. bizzozeronii infected gerbils, this was less pronounced. Focal apoptotic loss of gastric epithelial cells was spatially associated with the presence of bacteria especially in H. felis and to a lesser extent in H. bizzozeronii infected gerbils. This loss of cells may lead to intestinal metaplasia.

In vitro antimicrobial susceptibility testing of Helicobacter felis, H. bizzozeronii, and H. salomonis

The susceptibilities of Helicobacter felis (15 strains), H. bizzozeronii (7 strains), and H. salomonis (3 strains) to 10 antimicrobial agents were investigated by determination of the MIC using the agar dilution method. No consistent differences were noticed between the different Helicobacter species, which were all highly susceptible to ampicillin, clarithromycin, tetracycline, tylosin, enrofloxacin, gentamicin, and neomycin, as demonstrated by low MICs. Higher MICs were obtained for lincomycin (up to 8 microg/ml) and spectinomycin (up to 4 microg/ml). Two H. felis strains showed a MIC of 16 microg/ml for metronidazole, suggesting acquired resistance to this antimicrobial agent.

Prevalence of Helicobacter pullorum among patients with gastrointestinal disease and clinically healthy persons

Feces from 531 patients with gastroenteritis and from 100 clinically healthy individuals were tested for Helicobacter pullorum by use of PCR. Samples positive by PCR were qualified for isolation. H. pullorum DNA was demonstrated to be present in feces from 4.3% of patients with gastrointestinal disease but also in feces from 4.0% of clinically healthy persons. One strain was isolated from one patient with gastrointestinal disease.

Identification of non-Helicobacter pylori spiral organisms in gastric samples from humans, dogs, and cats

Tightly coiled bacteria are a rare cause of gastric pathology in humans and represent a mixture of species for which a zoonotic origin is suspected. Similar organisms are common inhabitants of the gastric mucosae of carnivores and pigs. It was the goal of the present study to determine the actual occurrence of each individual Helicobacter species in human, canine, and feline stomachs in order to better understand the possible zoonotic significance. Gastric biopsy samples from humans with histological evidence of non-Helicobacter pylori spiral bacteria (n = 123) and samples from the gastric antrum, corpus, and cardia from dogs (n = 110) and cats (n = 43) were subjected to a multiplex PCR, enabling the identification of Helicobacter felis, Helicobacter bizzozeronii, Helicobacter salomonis, and "Candidatus Helicobacter suis." A PCR for detecting H. pylori was applied to all human samples. Single infections with "Candidatus Helicobacter suis," H. felis, H. bizzozeronii, H. salomonis, a hitherto unknown genotype of a non-H. pylori spiral organism (Helicobacter-like organism 135 [HLO135]), and H. pylori were identified in 30.9%, 8.9%, 2.4%, 11.4%, 7.3%, and 8.9% of the human biopsy samples, respectively. Mixed infections (16.3%) with two or even three of these were also found. In the canine stomach, H. bizzozeronii (70.0%) was encountered as the main spiral organism, while H. felis (62.7%) and HLO135 (67.4%) were the predominant Helicobacter species found in the feline gastric mucosa. Although the majority of human non-H. pylori organisms are Helicobacter species naturally occurring in the stomachs of pigs, cats, and dogs, the frequent identification of H. salomonis in human gastric biopsy samples is in contrast to its rare identification in pet carnivore samples, urging us to suspect other sources of infection.

First report on the occurrence of 'Helicobacter heilmannii' in the stomach of rabbits

Gastric Helicobacter spp. have been described in a wide range of animal species, including dogs, cats, primates, swine, cattle and rodents. However, in lagomorphs--more specifically rabbits--gastric Helicobacter infections have never been reported. Biopsy specimens were collected from different stomach regions of 23 rabbits, including 10 pet rabbits, 10 industrial animals and 3 research animals. These were subjected to a PCR assay for the detection of Helicobacter DNA. Identification up to the species level was based on 16S rRNA sequence analysis and a recently developed multiplex PCR. Seven rabbits (four pet, one research animal and two industrial animals) tested positive in the Helicobacter genus-specific PCR in the stomach, with the corpus being predominantly positive. H. felis and H. salomonis, hitherto presumed to be naturally hosted by cats and dogs, were detected in three animals and one animal, respectively. One of these animals had been completely devoid of any form of contact with cats or dogs. A H. pullorum/H. rappini-like organism (96% 16S rDNA sequence similarity) was found in an industrially held rabbit. The helicobacters of the two remaining rabbits could not be identified up to the species level. To conclude, this is the first report on the occurrence of Helicobacter spp. in the stomach of rabbits. In view of the fact that H. felis and H. salomonis are put forward as having zoonotic potential, further research is necessary to investigate the implications of these findings not only for the rabbit but also for human health.

Helicobacter pylori and extragastric diseases--other Helicobacters

Reports on Helicobacter pylori and extragastric diseases have almost doubled this year compared with last year, bearing witness to the persistent scientific interest in this branch of Helicobacter-related pathology. Data belong increasingly to the area of vascular medicine, as well as hematology, dermatology, pediatrics and other fields. Unfortunately, these studies show overall controversial results, due to the impact of several confounding factors, and to the difficulty of recruiting homogeneous patient populations. Furthermore, many studies continue to be conducted on Helicobacter species other than H. pylori, focusing on animal models of gastroenterological illnesses which may retain strong similarities with human diseases. In this paper, taxonomy, detection and characterisation of Helicobacter spp. will be reviewed, together with the most important data issued this year on other Helicobacters and animal models.