Subsequently, in1985, as a result of perhaps a bruised ego or perhaps just a true dedication to education, the two decided unprecedented methods were now called for. They flipped a coin (unconfirmed) and Dr. Marshall came up the guinea pig. He then underwent a gastric biopsy in order to prove that his gut did not contain Helicobacter pylori. After this was established as truth, Marshall’s healthy stomach lining was now able to be the subject of experimentation, and the professor introduced Helicobacter pylori into his system to prove that this bacteria did indeed lead to gastric disorder.  

Initially thought to be Campylobacter spp., electron microscopy found differences in the flagella of the two, and 16S rRNA sequencing was used to confirm that H. phylori was not of the Campylobacter genus, and became the first Helicobacter genus species named. 

H. pylori can be found in the Bergey’s manual. While researching the ways with which H. pylori can be classified, it quickly became apparent that the many species within the Helicobacter genus can prove difficult to differentiate between and a technique known as “sodim dodecyl sulfate-polyacrylamide gell electrophoresis (PAGE) tends to be reliable to differentiate between the strains. PCR assays have been described for H. pylori, but as the Helicobacter species’ taxonomy is still developing, not all of the species have been evaluated against these PCR assays. Being an extremely heterogenous genomic species, H. pylori strains continue to prove even further uniquely difficult to differentiate between, as there is such a large extent of allele diversity within the strains that some taxonomists have suggested that “H. Pylori may exist as a species complex.”  

Sources:

-Solnick JV, Vandamme P. Taxonomy of the Helicobacter Genus. In: Mobley HLT, Mendz GL, Hazell SL, editors. Helicobacter pylori: Physiology and Genetics. Washington (DC): ASM Press; 2001. Chapter 5. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2463/

-Solnick JV, Schauer DB.2001.Emergence of Diverse HelicobacterSpecies in the Pathogenesis of Gastric and Enterohepatic Diseases. Clin Microbiol Rev 14:.https://doi.org/10.1128/cmr.14.1.59-97.2001

-

Phylum: Proteobacteria

Class: Epsilonproteobacteria

Order: Campylobacterales

Family: Helicobacteraceae

Genus: Helicobacter

Source: https://www.fws.gov/taxonomic-tree/525066

As such, it's been found that manipulation of even very subtle changes to the structure can significantly weaken the bacteria’s ability to colonize within the harshly acidic environment of the stomach. Researchers have found that some specific genes imperative for the helical structure are also imperative for the bacterial cell’s ability to destroy host cells. This impressively complex nature of function and form is another testament to the longevity of these bacteria and their subsequent evolution with the human species.  

Source: Taylor JA, Bratton BP, SIchel SR, Blair KM et al. 2020. Distinct cytoskeletal proteins define zones of enhanced cell wall synthesis in Helicobacter pylori. Elife 9:e52482. DOI:https://doi.org/10.7554/eLife.52482.

Source: O'Toole PW, Clyne M. Cell Envelope. In: Mobley HLT, Mendz GL, Hazell SL, editors. Helicobacter pylori: Physiology and Genetics. Washington (DC): ASM Press; 2001. Chapter 7. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2462/

Source: Heather Parker, Jacqueline I. Keenan,

Composition and function of Helicobacter pylori outer membrane vesicles,

Microbes and Infection,

Volume 14, Issue 1,

2012,

Pages 9-16,

ISSN 1286-4579,

https://doi.org/10.1016/j.micinf.2011.08.007.

(https://www.sciencedirect.com/science/article/pii/S1286457911002206)

As H. pylori is a relatively recently discovered bacteria that has been deemed a Class 1 carcinogen, extensive and varied research is being conducted on this bacteria. Being an obligate micoaerophile, growing colonies to perform tests on requires a limited-ozygen environment, and has been found to have an optimum growth temperature of 35C-37C.  

I found through my research that despite being able to populate the human stomach (interesting news on that party trick to follow), H. pylori is a needy bacteria to cultivate within the lab setting. Most of the successful growth mediums used where blood-based agars in an anaerobic jar, provided with some humidity, and placed upside down.  

Blanchard TG, Nedrud JG. Laboratory maintenance of helicobacter species. Curr Protoc Microbiol. 2006 Jan;Chapter 8:Unit8B.1. doi: 10.1002/9780471729259.mc08b01s00. PMID: 18770594; PMCID: PMC3357201. 

Jiang X, Doyle MP. Growth supplements for Helicobacter pylori. J Clin Microbiol. 2000 May;38(5):1984-7. doi: 10.1128/JCM.38.5.1984-1987.2000. PMID: 10790135; PMCID: PMC86644. 

Just as the geographic evolution of this bacteria has been varied, so has its ability to resist antibiotics. In certain areas, the species may be susceptible to or resistant against antibiotics for which a different species in a different location are not. This large scale variety of the bacteria is part of why it is such a major focus at this time, as multiple factors can lead to the increasing resistance of any species.  

Some of the important virulance factors contained by Helicobacter pylori species include its shape conversion ability, utilizing its spiral form to move about and its coccoid form when colonizing the inner layer of the stomach’s lining, initiating epigenetic changes within the host’s own epithelial cells, ability to destroy the mucus lining of the stomach and allowing the host’s own stomach acid to create trauma to the organ, altering signal between host’s cells, and its ability to form a biofilm that greatly increases its ability to resist antibiotics.   

These are only a handful of the many factors that aid this bacterium in being classified as a top carcinogen to its host. The intricate abilities of H. pylori to evade the host’s immune system are being researched and grouped based on individual, specific mechanisms caused by specialized genes to aid its placement as such a formidable foe.  

Chang, WL., Yeh, YC. & Sheu, BS. The impacts of H. pylori virulence factors on the development of gastroduodenal diseases. J Biomed Sci 25, 68 (2018). https://doi.org/10.1186/s12929-018-0466-9 

Thorell, K., Muñoz-Ramírez, Z.Y., Wang, D. et al. The Helicobacter pylori Genome Project: insights into H. pylori population structure from analysis of a worldwide collection of complete genomes. Nat Commun 14, 8184 (2023). https://doi.org/10.1038/s41467-023-43562-y 

Tomb JF, White O, Kerlavage AR, Clayton RA, Sutton GG, Fleischmann RD, Ketchum KA, Klenk HP, Gill S, Dougherty BA, Nelson K, Quackenbush J, Zhou L, Kirkness EF, Peterson S, Loftus B, Richardson D, Dodson R, Khalak HG, Glodek A, McKenney K, Fitzegerald LM, Lee N, Adams MD, Hickey EK, Berg DE, Gocayne JD, Utterback TR, Peterson JD, Kelley JM, Cotton MD, Weidman JM, Fujii C, Bowman C, Watthey L, Wallin E, Hayes WS, Borodovsky M, Karp PD, Smith HO, Fraser CM, Venter JC. The complete genome sequence of the gastric pathogen Helicobacter pylori. Nature. 1997 Aug 7;388(6642):539-47. doi: 10.1038/41483. Erratum in: Nature 1997 Sep 25;389(6649):412. PMID: 9252185. 

Testing for H. pylori via urea is the most widely used diagnostic, capitalizing on this bacteria’s functionally imperative method of survival within the low pH of the human stomach, the conversion of urea into ammonia and carbon dioxide. The ammonia created is able to accept Hydrogen and thus bring the surrounding area to a more basic pH. When a patient consumes a beverage or food that contains urea. Carbon dioxide produced as a byproduct can then be quantified via a breath test to indicate colonization by H. pylori. 

Blood tests can be used to detect antibodies; however, this isn’t the most helpful test because it cannot differentiate between whether you have had H. pylori in the past versus are currently colonized. There are two different tests available for feces, one testing for the antigen produced by H. pylori, the other a PCR that searches for antibiotic resistance genes of H. pylori. Both the serum and the fecal antigen tests utilize ELISA test methods which allows for an easier diagnosis in fields where medical equipment availability is more limited but can be less effective. 

A more invasive approach to the detection of H. pylori involves an endoscopy of the stomach, which can show changes in the tissue from a macroscopic level, as well as providing the ability to sample tissue to test outside of the body. One such test is a urease test; a simple diagnostic test performed via placing a tissue sample into a solution that contains urea and monitoring with a pH indicator. If H. pylori is present, it will convert the urea into ammonia and CO2, increasing the pH. However, there are other normal and abnormal flora that will do the same located in the same regions, so it can be considered a low specificity test.  

MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2020 Jun 24]. Heart attack; [updated 2020 Jun 10; reviewed 2016 Aug 25; cited 2020 Jul 1]; [about 5 p.]. Available from: https://medlineplus.gov/heartattack.html  

This is truly a case of “chaos for the fly” in that while these bacteria have managed to alter a bit of their surrounding environment (human’s stomachs) to allow them to stay and multiply, this alteration can cause severe repercussions for the host, presenting as painful gastric ulcers that can not only lead to chronic ulcer diseases, but oftentimes to cancer of the stomach or of the lymphoid tissues found in the stomach (MALT).  

The infiltration of stomach mucosa by H. pylori is painful and dangerous, as the damage done to the lining illicits a wide variety of immune responses from the host. While 50% of the world’s population are colonized by H. pylori, many remain asymptomatic. Those that do experience symptoms do so because of their own immune system’s efforts to vanquish the parasitic bacteria. Immune system components such as cytokines and interleukins can effective the functioning of the parietal cells of the stomach which produce the hydrochloric acid that is a necessary component of our gastrointestinal functioning, and this decrease in HCl only leads to further colonization by the bacteria as they have less hostile environments to colonize.  

Within the copious amounts of research being conducted on this bacteria, proving significant correlation between H. pylori and any disease system is made many time more difficult by the multitude of species known thus far, as well as the compounding variables presented  by the hosts of the bacteria (ie location, race, socioeconomic status). Despite this, studies are being worked on, and H. pylori’s relation to autoimmune diseases within the human body is being actively researched. Thus far in my own research, I have found a possible negative correlation between H. pylori and irritable bowel syndrome; meaning that those who suffer from IBD are less likely to be colonized by the bacteria. In contrast, there is some information that has found that a link between H. pylori and hepatic and/or endocrine autoimmunity is notably likely. Another somewhat controversial correlation being studied is the link between H. pylori and rheumatoid arthritis. 

Truly, when one considers the rapidly increasing knowledge we have of the importance of the human gut on every other physiologic system in the body, the amount of hypothesis for correlations between Helicobacter pylori and autoimmune disease processes are limitless and will likely take many more years to explore.   

Wang L, Cao ZM, Zhang LL, Dai XC, Liu ZJ, Zeng YX, Li XY, Wu QJ, Lv WL. Helicobacter Pylori and Autoimmune Diseases: Involving Multiple Systems. Front Immunol. 2022 Feb 10;13:833424. doi: 10.3389/fimmu.2022.833424. PMID: 35222423; PMCID: PMC8866759. 

The most common antibiotics for H. pylori are clarithromycin, amoxicillin, and metronidazole. A proton pump inhibiting drug (such as omeprazole; an over the counter treatment for indigestion, heartburn, and acid reflux) is imperative for treatment of H. pylori because it raises the pH of the stomach, making it less acidic. It has been found that H. pylori has a tendency to become resistant to antibiotics (particularly an issue with clarithromycin as it was the drug of choice for longest), and this resistance is typically found when H. pylori is in its coccoid form which occurs at lower levels of pH. The neutralizing proton pump inhibitor makes for an environment in which the bacteria is more likely to be found in its more common spiral shape, and thus less likely to be resistant to the antibiotics.  

Due to the far-reaching nature of this microbe, the rise in resistance to antibiotics ,and the reoccurrence of H. pylori in populations from which it was previously eradicated, the World Health Organization has declared Helicobacter pylori a “priority neglected target pathogen.”  

Sutton P, Boag JM. Status of vaccine research and development for Helicobacter pylori. Vaccine. 2019 Nov 28;37(50):7295-7299. doi: 10.1016/j.vaccine.2018.01.001. Epub 2018 Apr 5. PMID: 29627231; PMCID: PMC6892279. 

The prevalence rate of H. pylori has been mentioned in my semester long project many times. There are over 50% of the population of the world that are likely colonized by this bacterium. Some even have multiple species concurrently! It does not always cause issues and can remain undetected. As one would imagine, rates of infection are also typically higher in less developed countries.  

Finding clear morbidity and mortality data for Helicobacter pylori can prove difficult, as it is not necessarily the bacteria itself that will cause illness and possibly death; instead it is the associated illnesses that may come with the bacteria. As mentioned previously, many people in the world are colonized by H. pylori, but do not suffer any symptoms or signs of further illness. However, with previous immune issues, certain socioeconomic factors, geographic location, and other such factors, the bacteria can lead to development of serious ailments, including stomach cancer. In addition, there are over 1000 species of this microbe currently recognized, and certain species have genes that can make them much more likely to cause morbidity and mortality.  

https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/h-pylori-fact-sheet#what-factors-increase-the-likelihood-that-h-pylori-infections-will-be-harmful 

https://my.clevelandclinic.org/health/diseases/21463-h-pylori-infection 

This patient was a 40-year-old male, with no historical medical issues, no documented chronic illness, was not on any medications, and was in top physical form, no doubt contributed to by the patient’s occupation as part of an armed security group in the Middle East. Due to this circumstance, the patient was in close quarters with teammates, sharing workout equipment, dining area, and living together. As we have seen from my presentations over this semester, H. pylori is most commonly found and is generally most likely to pose a problem in areas of the world with lower socioeconomic statuses and denser populations. In this particular case, the patient received majority of his hydration via a main local mineral water source that is bottler, and foods that are produced locally. The patient also regularly exercises and consumes dietary supplements to keep fat from accumulating as well as to promote muscle growth.  

Initially, the patient presented for intermittent pain in his abdomen that he described as “burning”, with cramping and nausea. The patient was not experiencing any diarrhea or vomiting, and only a mild reduction to his appetite. Upon physical exam, the patient was found to be within normal range for vitals and there was no obvious sounds, masses, or causes of pain. The patient was prescribed an anti-spasm medication for gastointestinal upset, a proton pump-inhibiting drug for stomach acid, and advised to discontinue all supplements and make sure to stay hydrated.  

The patient returned to the clinic five days later with a pain in the abdomen that he scored as 10/10 and said was now radiating across the chest and into the left and right flank. Patient reported that all of his previous symptoms had only worsened, and he was now also feeling very bloated, and these symptoms had been constant for five hours. Physical exam showed normal vitals, no visual abnormalities noted, but pain elicited upon palpation of the epigastric region. Patient found that lying on his back alleviated some of the pain. While under care, the patient received metronidazole, a stomach antibiotic, and paracetamol, a medication for pain relief that is indicated in patients with gastrointestinal upset) intravenously. He was sent home with omeprazole, metronidazole, and clarithromycin to be taken over the next two weeks. When discharged, he was advised to only perform light duties for two days and recheck in 24 hours.  

Without capabilities for a urea breath test or fecal testing to confirm Helicobacter pylori, the hospital took an empirical approach to treating this patient with the assumption that H. pylori was the culprit. Within twelve hours the patient's burning sensation had lessened and a follow-up 24 hours after the patient reported he was feeling well, appetite was increasing, the pain was not present and there was a small amount of acid reflux left. In the next week this patient reported no more pain and only minimal discomfort of the abdomen after eating. At the two-week follow-up, he had returned to normal appetite and was asymptomatic.  

This patient reported that he believed he was suffering for weeks prior to seeking treatment and had assumed it was due to the stressful environment he was in as well as possible side effects of supplements he was taking for fat loss.  Being in a job traditionally representative of male strength, this patient admitted that he would likely have come forward for diagnosis earlier had he not been ignoring many symptoms in an attempt to appear stoic.

This case study is also representative of a common conversation among healthcare providers in less populated areas. How to diagnose and treat H. pylori versus other pathogens or problems. It’s made further difficult by the terminology of pain and location, as we can not precisely indicate the organ or area that is affected when it comes to the abdomen.