Evaluation of Co-existence of Helicobacter pylori and candida in the Oral Cavity of Dyspeptic patients

In our group comprising of 70 subjects, 60 patients presented with symptomatic gastritis and 10 were asymptomatic subjects who served as the control group. The symptomatic gastritis subjects had undergone endoscopy and gastric biopsy specimen was collected. Histopathologically, the biopsy specimen was observed for the presence of Helicobacter pylori. The subjects were divided into 3 groups. Group I comprised of 30 subjects with Helicobacter pylori in their gastric mucosa. Group II comprised of 30 subjects without Helicobacter pylori in their gastric mucosa. Group III comprised of 10 asymptomatic controls. • We found that there was a male predominance for gastritis in our study groups. The symptomatic gastritis was more commonly seen between the 3rd and 5th decade of life. • Our study findings conclude that subjects who are less than 30 years of age are more prone to have Candida in their saliva. • There was no difference in the mean CFU between the study groups and the mean CFU between the age groups did not show statistical difference. But, when stratified between gender, there was an increase in CFU with increasing age. • We found that oral candida carriage was more frequently seen in the younger age group and odd’s have shown that when compared to subjects above 50 years, symptomatic subjects less than 30 years have 7.5 times higher risk of getting salivary candidal carriage. • We found that there is no correlation between the presence or absence of salivary Helicobacter pylori and the presence or absence of Helicobacter pylori in the gastric mucosa. There was no correlation between salivary candida and the presence or absence of Helicobacter pylori in the gastric mucosa. • In our study, the patients with Candida and Helicobacter pylori in the saliva had 8 times more chance of having gastritis with Helicobacter pylori positivity in their gastric mucosa than in whom these organisms were not detected. • Further studies are needed to understand the relationship of Helicobacter pylori, Candida and gastritis

Helicobacter pylori infection and transmission in Africa: Household hygiene and water sources are plausible factors exacerbating spread

Helicobacter pylori (H. pylori) is a microaerophilic motile curve rod that inhabits the gastric mucosa of the human stomach. The organism chronically infects billions of people worldwide and is one of themost genetically diverse of bacterial species. Infection with the bacterium which leads to chronic gastritis, peptic ulceration, gastric cancers and gastric malt lymphoma has been reported to follow a pattern linked to geographic and socio-demographic factors. Studies have documented a higherprevalence in Africa than elsewhere although the pathological outcomes do not correlate with infection. H. pylori transmission pathways are still vague, but the risks of transmission include precarious hygiene standards, over-crowding and contaminated environment and water sources amongst others. The possible routes of transmission include oral-oral, faecal-oral and person- to -person, either with or without transitional transmission steps during episodes of diarrhoea or gastro-oral contact in the eventof vomiting. Use of contaminated water including municipal tap water has also been suspected to have a high impact in the transmission of the organism. To generate the data presented in this paper, we conducted an internet based search on relevant literature pertaining to H. pylori epidemiology in general and Africa in particular. Sites such as Pubmed, AJOL, Scopus and Goggle scholar were mainly used. This paper therefore attempts to appraise the role of household hygiene and water sources in the transmission of this organism in the developing world context

Prevalence, diversity and disease association of <i>Helicobacter pylori</i> in dyspeptic patients from Pakistan

Introduction: The etiological association of Helicobacter pylori with gastric ulcer (GU), gastric cancer (GC), and duodenal ulcer (DU) is well-known. Understanding the epidemiology of H. pylori facilitates the estimation of disease burden in a certain population. This study presents the diversity of H. pylori genotypes and their association with different clinical outcomes among dyspeptic patients in Pakistan over a period of four years. Methodology: Gastric biopsy samples from a total of 450 dyspeptic individualswere subjected to PCR, genotypingand histology. Results: A total of 201 (45%) cases were found positive for H. pylori. The detection rate was high in GU (91%), DU (86%) and GC (83%) cases compared with those cases who had intact gastric mucosa (18%). Histology revealed the presence of infection in 68% of cases of mild/chronic nonspecific gastritis with others belonging to the GU sequel. cagA gene carriage was observed in 104 (51%) cases or mostly from DU, GU and GC groups, of which 97 were Western type strains while 3 were East-Asian type strains that are rarely observed in South Asia. vacA allelic variant s1am1 was most commonly observed, followed by s1am2, and s1bm1, with direct correlation in diseased cases (gastritis, GU, DU and GC). Prevalent genotypic combinations were s1am1/cagA- in gastritis and s1am1/cagA+ in DU, GU, and GC. Conclusions: Our study indicates the predominant circulation of Western type cagA and vacAs1am1 type H. pylori strains in Pakistan.</br

Mechanisms of Helicobacter pylori Adhesion Regulation and Impacts on Host Immune Response

Helicobacter pylori is a gram-negative bacterium that colonizes the human gastric mucosal layer of 50% of the world’s population. H. pylori utilizes a variety of adhesin proteins to adhere to the gastric epithelial layer, allowing the bacterium to successfully colonize its host, gain access to nutrients, and persist even during gastric mucosal shedding. The present study investigates transcriptional regulation of adhesin-encoding genes sabA and hopZ in the H. pylori strain J99. Several adhesin-encoding genes, including sabA and hopZ, possess a repeating homopolymeric nucleotide tract within their promoter region and a poly-cytosine-thymine (poly-CT) tract downstream of the translational start site. Strain J99\u27s sabA promoter homopolymeric tract consists of 18 thymines, whereas the hopZ promoter has a poly-adenine tract composed of 14 adenines. Both sabA and hopZ are phase-off , i.e., full-length protein cannot be synthesized, in the wild-type based upon poly-CT tract repeat lengths of 8 and 6 respectively. We used site directed mutagenesis to extend and truncate the poly-thymine or poly-adenine tract to determine whether altering lengths of these homonucleotide tracts affects transcription frequency of sabA or hopZ. Using qRT-PCR, we found that extending or truncating the poly-thymine tract of sabA or the poly-adenine tract of hopZ by five thymines or adenines respectively increases transcription frequency of these adhesin-encoding genes. In addition, alterations in the poly-CT tract of sabA to switch phase status to phase-on led to significant increases in transcription frequency of sabA. However, phase-on and poly-T tract extension mutations did not have synergistic effects on sabA transcription frequency. Phase-on mutations, but not poly-thymine tract mutations, increased H. pylori’s adhesion to human gastric epithelial cells. Not only did the phase-on mutants increase H. pylori adhesion, but also induced more inflammatory cytokine interleukin-8 (IL-8) production by the human gastric epithelial cells. Overall, the present study examines different mechanisms of H. pylori adherence regulation at the genetic level and effects on the host inflammatory immune response

Genotypes of Helicobacter pylori isolates in Gambian children and adults

Helicobacter pylori is a globally important and genetically diverse gastric pathogen that infects most people in developing countries. Earlier reports indicated high prevalence of H. pylori colonization, but a low frequency of H. pylori-associated diseases in Africa but recent reviews have shown that gastroduodenal disease is actually common in Africa. Most detailed analyses of H. pylori have used strains from non-African countries, despite the high importance of Africa in the emergence and evolution of humans and their pathogens. There have been far fewer critical studies such as genotypes in association with gastric disease, population genetics and antimicrobial resistance and susceptibility of H. pylori strains from Africa. It is with this background that the genotypes of H. pylori in association with gastroduodenal diseases, antibiotic susceptibility to commonly used drugs and population genetics from ethnic African adults and children in The Gambia were investigated. In this study, it was found that the prevalence of H. pylori is high in dyspeptic patients in The Gambia and that many strains were of the putatively more virulent cagA+, vacAs1 and vacAm1 genotypes. There was a high prevalence of cagA positive strains in patients with overt gastric diseases than those with non-ulcerative dyspepsia; conversely, the co-existence of both cagA+ and cagA- was found to be protective against the development of gastroduodenal disease. Analyses of the sequenced data with the STRUCTURE software indicated that Gambian H. pylori strains were closely related to hspWAfrica than to strains from more distant African regions (hspSAfrica and hpNEAfrica) indicating common ancestral origin. Essentially no traces of European or North African ancestry were found despite Gambia's history of invasion and colonisation by peoples from these regions during the last millennium. Antibiotic susceptibility tests have shown that Gambian strains were found to be highly sensitive to clarithromycin, erythromycin, tetracycline and amoxicillin but found that more than two-thirds of Gambian H. pylori strains were metronidazole resistant. These data indicate caution in use of metronidazole-based therapies in The Gambia. This thesis provides a detailed initial description of a set of H. pylori isolates directly related to a geographically defined West African population. The data presented has answered some relevant questions on H. pylori virulent genes in association with gastro-duodenal diseases and antibiotic susceptibility providing a comprehensive basis for future studies

Past human health and migration : the analysis of microbial DNA associated with human remains recovered from a glacier in Canada

In paleopathology, the assessment of disease occurs through macroscopic observation, which is dependent on the preservation of the sample and the experience of the observer. Many disease events do not leave any visible signatures and therefore go undetected. The relatively new field of paleomicrobiology incorporates molecular techniques where microbial DNA, if present, is amplified from an archaeological sample. The identification of genetic material from micro-organisms, including bacteria and viruses, can confirm a diagnosis that was originally based on visible osteological or mummified tissue changes. Even more promising is the capability of molecular technology to detect microbial DNA evidence of disease processes that were not visibly evident. Based on phylogenetic analyses of modern isolates, scientists have concluded that micro-organisms such as Mycobacterium tuberculosis and Helicobacter pylori have been associated with humans for thousands of years. M. tuberculosis is the causative agent of the disease tuberculosis, and H. pylori is known for its role in gastritis and peptic ulcers. Both are pathogenic bacteria that still impact the health of modern populations. Through the analysis of microbial DNA from these two bacteria in skeletal and mummified tissue, data can be accumulated regarding the spatial and temporal impact of these infections. Interestingly, due to the lengthy association between these bacteria and humans, phylogenetic studies on modern strains have shown that strain characterizations of both M. tuberculosis and H. pylori bacteria reveal connections with past human migrations. In 1999, human remains were discovered eroding out of a glacier in northern British Columbia, Canada on the traditional territory of the Champagne and Aishihik First Nations. The Aboriginal elders named the site Kwäday Dän Ts’ìnchi, which means ‘long ago person found.’ Radiocarbon testing of bone collagen and artifacts from the site suggested a time-frame of approximately AD 1670 to 1850, which is either pre-European contact or early post-contact for that area. I analyzed the tissues of the ancient individual specifically for genetic evidence of M. tuberculosis and H. pylori to identify partial health status and determine if a connection could be made to strains associated with European populations to clarify whether the site was pre or post-European contact. Through polymerase chain reaction (PCR) testing of the individual’s tissues with primers specific for the IS6100 insertion sequence, TbD1, and Rv3479, katG and gyrB genes, I identified evidence of a possible latent tuberculosis infection. Genetic characterization of the katG gene associated with the ancient M. tuberculosis strain revealed a potential connection with European strains. Amplification and sequencing of the gyrB gene fragment indicated the presence of two alleles that may have been the result of a selective pressure. PCR testing of the individual’s stomach tissue with specific primers for regions with the vacA gene resulted in a positive identification of H. pylori DNA. Genetic characterization of this virulence-associated gene indicated that the strain contained a vacA signal (s) region s2 allele. This allele is more commonly identified in Western strains that do not cause disease, which suggests that the individual had no gastric symptoms and that European strains were present in northwestern Canada at that time. The vacA middle (m) region contained a hybrid m2a/m1d sequence. Modern hybrids are rare but they have been identified in Asian strains. Studies have shown that the m2a allele is more common in Western strains. A phylogenetic analysis identified that the m1d region clusters with previously published novel strains associated with Aboriginal individuals that are closely related to Asian strains. This indicates a past connection between the ancient individual and his ancestors who arrived in the New World from Asia thousands of years ago

Helicobacter pylori infection in paediatric patients with dyspeptic symptoms

Ph.DDOCTOR OF PHILOSOPH