Antacids--a risk factor in travellers brucellosis?

The Phylogeny and Biological Function of Gastric Juice-Microbiological Consequences of Removing Gastric Acid

Gastric juice is a unique combination of hydrochloric acid (HCl), lipase, and pepsin. Acidic gastric juice is found in all vertebrates, and its main function is to inactivate microorganisms. The phylogenetic preservation of this energy-consuming and, at times, hazardous function (acid-related diseases) reflects its biological importance. Proton pump inhibitors (PPIs) are one of the most widely used drugs in the world. Due to the reduced prevalence of Helicobacter pylori infection as well as the increased use of inhibitors of gastric acid secretion, the latter has become the most important cause of gastric hypoacidity. In the present manuscript, we review the microbiological consequences of removing gastric acidity. The resulting susceptibility to infections has not been studied extensively, and focus has mainly been restricted to bacterial and parasitic agents only. The strongest evidence concerning the relationship between hypochlorhydria and predisposition to infections relates to bacterial infections affecting the gastrointestinal tract. However, several other clinical settings with increased susceptibility to infections due to inhibited gastric acidity are discussed. We also discuss the impact of hypochlorhydria on the gut microbiome.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Gastric juice: a barrier against infectious diseases

All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.

Conventional dose of omeprazole alters gastric flora

Quantitative cultures were carried out on samples from gastric juice obtained from 12 ambulatory patients with esophagitis before and one month after omeprazole therapy. An increase in the number of patients in whom gastric juice was culture-positive, as well as an increment in the bacterial counts were noted. The spectrum of microorganisms isolated from gastric juice was identical to the normal flora of the oral cavity, mainly alpha-hemolytic streptococci, corynebacteria, and Candida species. Thus, the counts of organisms within gastric contents are simply a reflection of swallowed oral microflora that were able to survive due to the less acidic environment.

Review article: infective complications of therapeutic gastric acid inhibition

Gastric acid secretion has a non-specific bactericidal action which contributes to gastrointestinal defence mechanisms against micro-organisms. Therapeutic inhibition of acid secretion with histamine H2 receptor antagonists and proton pump inhibitors might therefore be expected to predispose to infection. This article reviews clinical reports of infection occurring during therapeutic gastric acid inhibition, and assesses the risk of infection incurred by such treatment. Non-typhoid salmonelloses, Campylobacter infections, local candidiasis, and possibly Strongyloides hyperinfections may be more prevalent after acid inhibitory treatment, but concurrent impairment of other gastrointestinal defence mechanisms may be necessary to permit infection.

Ocular brucellosis

Though brucellosis has been eradicated from many countries, it remains a health problem in many developing countries. We report hereon a 34-year-old woman who presented with recurrent attacks of uveitis unresponsive to treatment with steroids. She was found to have systemic brucellosis, and Brucella melitensis was isolated from a paravertebral abscess. The condition responded to systemic antibiotics, and she completely recovered from her uveitis.

Salmonella and Shigella infections in Switzerland, with special reference to typhoid vaccination for travellers

This prospective study reveals that 48% of 368 salmonelloses and 81% of 43 shigelloses diagnosed within one year in the Zurich area were imported from abroad. Travellers in close contact with the local population have a higher risk of being affected by typhoid fever or shigellosis than the average tourist. The clinical course was generally mild, and there was no lethal case. As the incidence of Salmonella typhi is very low, typhoid vaccination is recommended only for high-risk travellers.

Antacids and peptic ulcer--a reappraisal

Antacids can reduce gastroduodenal acidity for long periods if taken in substantial quantities after food. Their healing effect on gastric ulcer is minimal, if present at all, and easily overwhelmed by the benefit obtained from admission to hospital. Intensive antacid therapy appears effective in healing duodenal ulcer and preventing haemorrhage from stress ulcer, and is comparable in these respects with cimetidine but with a higher incidence of side-effects. Clinical impression strongly suggests that antacids relieve pain in peptic ulcer but objective confirmation is lacking.