Helicobacter 1

 

Helicobacter pylori is a spiral shaped bacterium that lives in the stomach and duodenum (section of intestine just below stomach). It has a unique way of adapting in the harsh environment of the stomach.

The inside of the stomach is bathed in about half a gallon of gastric juice every day. Gastric juice is composed of digestive enzymes and concentrated hydrochloric acid, which can readily tear apart the toughest food or microorganism. Bacteria, viruses, and yesterdays steak dinner are all consumed in this deadly bath of chemicals. It used to be thought that the stomach contained no bacteria and was actually sterile, but Helicobacter pylori changed that.

The stomach is protected from its own gastric juice by a thick layer of mucus that covers the stomach lining. Helicobacter pylori takes advantage of this protection by living in the mucus lining.

Urea hydrolysis: urea is broken down to ammonia and carbon dioxide

Once H. pylori is safely ensconced in the mucus, it is able to fight the stomach acid that does reach it with an enzyme it possesses called urease. 

Urease converts urea, of which there is an abundant supply in the stomach (from saliva and gastric juices), into bicarbonate and ammonia, which are strong bases. This creates a cloud of acid neutralizing chemicals around the H. pylori, protecting it from the acid in the stomach. The reaction of urea hydrolysis is important for diagnosis of H.pylori by the breath test

Another defense H. pylori has is that the body's natural defenses cannot reach the bacterium in the mucus lining of the stomach. The immune system will respond to an H. pylori infection by sending white cells, killer T cells, and other infection fighting agents. 

However, these potential H. pylori eradicators cannot reach the infection, because they cannot easily get through stomach lining.

They do not go away either, though, and the immune response grows and grows. Polymorphs die, and spill their destructive compounds (superoxide radicals) on stomach lining cells. Extra nutrients are sent to reinforce the white cells, and the H. pylori can feed on this. within a few days, gastritis and perhaps eventually a peptic ulcer results. 

It may not be H. pylori itself which causes peptic ulcer, but the inflammation of the stomach lining; i.e. the response to H. pylori.  H. pylori is believed to be transmitted orally. Many researchers think that H, pylori is transmitted orally by means of fecal matter through the ingestion of waste tainted food or water. 

In addition, it is possible that H. pylori could be transmitted from the stomach to the mouth through gastro-esophagal reflux (in which a small amount of the stomach's contents is involuntarily forced up the esophagus) or belching, common symptoms of gastritis. The bacterium could then be transmitted through oral contact.

 

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Prevalence of H. pylori infection correlates best socio-economic status rather than race. 

In the United States, probability of being infected is greater for older persons (>50 years = >50%), minorities (African Americans 40-50%) and immigrants from developing countries (Latino > 60%, Eastern Europeans > 50%). 

 

The infection is less common in more affluent Caucasians ( < 40 years = 20%). The green square represents the total population in the United States of uninfected (normal) persons within which is a circle representing the 30% who are infected (HP+). 

  
Persons in the infected group develop duodenal ulcer at the rate of about 1% per annum so that approximately one third eventually have peptic ulcer disease.

The smaller circles represent diseases associated with H. pylori. Nearly all persons with duodenal ulcer are infected. Conversely, it is very unlikely that persons without H. pylori will ever develop duodenal ulcer. Gastric ulcer is usually caused by H. pylori, but about 30% of gastric ulcers in the

United States occur in persons without H. pylori and can be related to aspirin and other non steroidal anti-inflammatory drugs (NSAIDs). Most gastric adenocarcinomas and lymphomas occur in persons with current or past infection with H. pylori. In developing countries the ulcer groups are smaller and the gastric cancer group may be larger. For example, in northern Brazil, gastric cancer is the most common malignancy in men.

Western Countries

In general, the following statements can be made to summarize prevalence of H.pylori in Western countries:

• H.pylori affects about 20% of persons below the age of 40 years, and 50% of those above the age of 60 years.
• H.pylori is uncommon in young children.
• Low socio-economic status predicts H.pylori infection.
• Immigration is responsible for isolated areas of high prevalence in some Western countries.

Studies of sera from epidemiologists and Californians show that a 50% decline in the prevalence of H.pylori has occurred in the United States since 1968.

Developing Countries

In developing countries most adults are infected. Acquisition occurs in about 10% of children per annum between the ages of 2 and 8 years so that most are infected by their teens. It is evident from careful surveys that the majority of persons in the world are infected with H.pylori.

H.pylori can be cultured from the stools in most infected persons (using special techniques). This is evidence that spread by fecal oral contact with infected persons is likely. In addition, polymerase chain reaction (PCR) can detect H.pylori in dental plaque from 30% of persons with the gastric infection. This may be a less common source of transmission.

 

Helicobacter pylori (H.pylori for short) was first discovered in the stomachs of patients with gastritis & stomach ulcers nearly 25 years ago by Dr Barry J. Marshall and Dr J. Robin Warren of Perth, Western Australia. At the time (1982/83) the conventional thinking was that no bacterium can live in the human stomach as the stomach produced extensive amounts of acid which was similar in strength to the acid found in a car-battery. Marshall & Warren literally “re-wrote” the text-books with reference to what causes gastritis & gastric ulcers.
 
In recognition of their very important discovery, they were Awarded the 2005 Nobel Prize for Medicine & Physiology.

H.pylori is a cork-screw shaped Gram-negative bacterium which is found to be present in the stomach-lining of ~3 billion people around the world (i.e. half the world’s population) and is the most common bacterial infection of man. Many of those carrying the bacterium have little or no symptoms & are apparently well, but all without exception have inflammation of the stomach lining, a condition which is called "gastritis". 

Gastritis is the underlying condition which eventually causes ulcers and other digestive complaints. If a person has had an H.pylori infection constantly for 20-30 years, it can lead to cancer of the stomach. This is the reason that the World Health Organisation's (WHO) International Agency for Research into Cancer (IARC) has classified H.pylori as a “Class- I-Carcinogen” i.e. in the same category as cigarette smoking is to cancer of the lung & respiratory tract.

I am compiling a bit of a list: Can you add to it?

1. Ayatollah Khomeini; (Died from intestinal bleeding, most Iranians have HP).
2. Lorne Greene; (Of Bonanza fame. Died from peptic ulcers and pneumonia complication, I only know what I saw on the cover of National Enquirer).
3. James Joyce; (Family history of stomach cancer and died of a perforated ulcer as per your letter). Most people born before 1940 would have had HP as adults, especially in Ireland.
4. George Bush; (At one time in the 60's had a duodenal ulcer; lots of men in the CIA have HP because they have lived overseas, particularly Latin America.)
5. Pope John Paul II; (Had gastric bleeding in the 1980's. Most Poles have HP).
6. Imelda Marcos; (Had gastritis and gastric bleeding during her N.Y. court case; most Filipinos have HP).
7. Stonewall Jackson; (Was known as a terribly grumpy dyspeptic by his doctor!). HP infection rate was very high in USA before 1900.
8. My great grandfather. (A Scott. Bled to death in hospital with a duodenal ulcer. Family blamed his fondness of citrus fruit!)
9. My father in-law; (Gastric problems ever since WW2. Blamed army food! Better since treated for HP in 1993!)
10. Alfred Nobel.  According to his biographer, he complained of chronic indigestion, headaches and depression.  His treatment, if it could be called that, consisted of baths, resting and drinking special types of mineral water especially at health spas.  For want of a better diagnosis, many attributed his complaints to stress, based on the spurious concept that mental activity can lead directly to elevated levels of stomach acid and other organic conditions.  Trying to sum up his life in one terse sentence, he offered the following: "I am a misanthrope and yet utterly benevolent, have more than one screw loose yet am a super-idealist who digests philosophy more efficiently than food."  Reflecting on these matters, we can assume that he was infected with Helicobacter pylori, as were most people in Europe at the turn of the century.  So it is appropriate that this man, who probably suffered Helicobacter pylori based duodenal ulcer disease, has now awarded a prize for the ulcer-causing bacterium.  Alas, the Marshall and Warren prize was 110 years too late to help the philanthropic Mr Nobel.  Read more about his health at this link.
11. Charles Darwin. Even before his famous voyage, Darwin was squeamish, although many attributed his nausea to sea-sickness which, for some reason, persisted.  He pent the rest of his life vomiting and complaining of gastronitestinal upsets.  He did have many other symptoms but he always focussed on his stomach as the major organ involved.  On the last day of his Life, Charles Darwin vomited some blood then died a few hours later.  In the 21st century, if darwin presented to a general practitioner, he would immediately have a Helicobacter serology and/or a urea breath test performed and then would be treated with antibiotics.  Further symptoms would have been investigated with an endoscopy.  At a time when almost everyone was infected with H.pylori, peptic ulcer could only be diagnosed at post mortem or if a patient suffered from G.I. bleeding.  So Charles Darwin had Helicobacter and hardly needed any other cause to explain his symptoms.  Other theories about his illness were concocted before H.pylori was discovered.  The origin of the species which troubled Darwin was probabaly Helicobacter pylori.  I will add to this on my blogspot page ( http://barryjmarshall.blogspot.com/ ). http://www.helico.com