Abstract
Background Helicobacter pylori infection affects approximately 40 million individuals in Turkey. Our prefecture is an endemic area for H. pylori infection and brucellosis. However, there are no data on the H. pylori prevalence among patients with brucellosis.
Objectives The primary aim of the current study was to investigate the link between H. pylori infection and brucellosis. The secondary aim was to determine the seroprevalence of H. pylori infection in healthy individuals.
Methods Between May 2010 and May 2011, serum was collected from patients with Brucella infection (n = 111) and healthy individuals (n = 120) and analyzed using an enzyme-linked immunosorbent assay kit. Brucella infection was defined as a positive Wright test or blood culture positivity for Brucella in conjunction with disease symptoms and findings.
Results Among the 111 patients with brucellosis, 69% (n = 77) had a seropositivity result for H. pylori IgG. The healthy control subjects had an 87% (n = 104) seropositivity for H. pylori IgG. The serum H. pylori IgG antibody seropositivity was significantly lower in the patients with Brucella infection compared with the control subjects (P < 0.001).
Conclusion Our results show that the serum prevalence of H. pylori among the patients infected with brucellosis is significantly lower than that in the control population. A negative correlation between H. pylori infection and brucellosis infection might be hypothesized.
Helicobacter pylori is a gram-negative, motile, microaerophilic, flagellated spiral bacilli that was first identified from the gastric epithelium of patients with chronic gastritis.1Infection with H. pylori is frequently associated with a diverse spectrum of gastrointestinal diseases, including gastric and duodenal ulcers, gastric adenocarcinoma, mucosa-associated lymphoid tumors and gastric non-Hodgkin lymphoma.2
The tests that are commonly used to detect H. pylori are classified as invasive or noninvasive tests. Invasive tests are based on endoscopic examination and include a biopsy urease test, histologic examination, and culture. Noninvasive tests are performed on the serum, stool, and breath.3The simplest diagnostic method to detect the H. pylori status is a serologic assay of H. pylori–specific IgG levels in the serum with an enzyme-linked immunosorbent assay (ELISA). The measurement of the levels of anti–H. pylori IgG antibodies in the serum is an easy and potentially less expensive test to confirm the infection. This test is also widely used to detect H. pylori–infected persons, particularly in seroepidemic studies worldwide.4
The prevalence of H. pylori is approximately 50% in Turkey.5The eastern part of Turkey is considered a hyperendemic area for H. pylori infection and brucellosis.6
Perhaps more importantly, the clinical impact of identifying H. pylori infection in patients with brucellosis remains unclear. The importance of food–H. pylori interactions in humans is increasingly recognized. Therefore, our aim was to determine the prevalence of H. pylori among patients with acute brucellosis infection.
MATERIALS AND METHODS
From May 2010 to June 2011, serum H. pylori IgG levels were measured with an ELISA in patients with Brucella infection (n = 111; 72% women; median age, 52 years) and healthy controls (n = 120; 61% women; median age, 48 years).
The diagnosis of acute Brucella infection was established by the presence of specific IgM antibodies against Brucella, as determined with an ELISA.
H. pylori infection was defined as the presence of H. pylori IgG in the serum. Serologic evaluation was performed with ELISA (Pyloriset EIA-G by Orion Diagnostica, Espoo, Finland).
The exclusion criteria for both groups were as follows: treatment with a proton pump inhibitor in the last 3 months and anti–H. pylori treatment in the last 6 months. We analyzed the H. pylori frequency in patients with acute brucellosis. Patients with acute brucellosis were not receiving any treatment.
The control group consisted of 120 healthy subjects (without a history of chronic or recurrent diseases). The control group had no dyspeptic complaints. Patients with prior usage of proton pump inhibitors and antibiotics were excluded from the study. All of the sera from the control group were obtained during the study period.
Both the study patients and the control subjects were resident in rural areas of Van city.
The study protocol was performed in accordance with the Helsinki Declaration as revised in 2002. All of the cases were duly informed, and their written consent was received.
Statistical Analysis
Numeric values were determined as percentage or mean ± SD. The nonparametric Kruskal-Wallis test was used for qualitative results, and the χ2 test was used for qualitative results between features. SPSS for Windows software, version 12 (Chicago, IL) was used for the statistical analysis.
RESULTS
There were no statistically significant differences between the 2 groups with regard to age, sex, and body mass index (P > 0.05).
Serum H. pylori antibody titers were evaluated as negative or positive. However, titers more than 1.2 IU/mL were accepted as positive (Table 1).
Serum IgM antibodies against Brucella titers were significantly higher in the patients with brucellosis compared with the control subjects (P < 0.001; Table 1).
There were no socioepidemiologic or residential differences between the groups.
Among the 111 patients with brucellosis, 69% (n = 77) had a seropositivity result for H. pylori IgG. The healthy control subjects had an 87% (n = 104) seropositivity for H. pylori IgG (Table 1).
The serum H. pylori IgG antibody seropositivity was significantly lower in the patients with Brucella infection compared with the control subjects (P < 0.001).
DISCUSSION
Brucellosis and H. pylori infection are distinct infectious diseases that arise as a result of different environmental effects. No reliable data exist on the prevalence of H. pylori in patients with acute brucellosis.
In our study, we found that the prevalence of H. pylori was decreased in the patients with brucellosis compared with the controls. Furthermore, we suggest that there is a negative link between brucellosis and H. pylori infection.
Brucellosis is a zoonotic disease and may affect every organ system in the human body.7The major risk factors for human brucellosis include the consumption of nonpasteurized milk products and close contact with infected animals.8
Brucellosis is a hyperendemic disease in Turkey and the Mediterranean basin.7,9Most of the Turkish cases have been reported in the eastern part of the country, where the consumption of traditionally produced unpasteurized milk-based cheese is common.10
The risk of H. pylori infection has historically been related to poor hygienic conditions and a lack of infrastructure.11The H. pylori seroprevalence in Turkey has been found to be as high as 95%.12
Many environmental factors contribute to the higher incidence of H. pylori in the eastern part of Turkey. The risk of H. pylori infection is also increased in persons who live in rural areas. This increase may be because farmers are often subjected to contamination of the gastrointestinal tract, which may lead to the colonization of environmental microorganisms.
Despite intense interest in the role of food intake in the pathogenesis of H. pylori infection, the pathways that contribute to disease evaluation in vivo are poorly understood. Many studies have supported the protective role of probiotics against H. pylori.13It has been clearly demonstrated that the consumption of raw farm milk is not significantly associated with H. pylori infection in farmers.14
In a Turkish study, the presence of H. pylori was investigated in sheep milk that is commonly used for traditional cheese, and H. pylori was not isolated in any milk sample.15Unpasteurized milk products may enhance the efficacy of anti–H. pylori treatment.16,17In addition, milk products containing probiotic strains may have a favorable effect on H. pylori infection in humans.18The most important of these products is traditionally produced unpasteurized cheese, which has a major role as a carrier for metabolically active probiotics.19Herb-enriched Turkish cheese is also historically considered a source of probiotics and brucellosis.20
A close relationship between the periplasmic core complexes of Brucella suis and H. pylori has been reported.21However, the effect of this phenomenon on clinical diseases remains unclear.
As expected, there are a few limitations of this study. First, this study had a case-control design. Second, the number of patients was small. However, this is the first study to show the relationship between H. pylori and brucellosis. Further studies with larger populations are needed to explore this relationship.
In conclusion, we found a significantly reduced serum prevalence of H. pylori among the patients infected with brucellosis. In addition, these data support the hypothesis that herb-enriched cheese-derived products may play an important role against H. pylori. Finally, our data suggest that the herb-enriched cheese produced from nonpasteurized milk could be a source of probiotics, preventing infection with H. pylori. These findings may suggest the potential development of novel protective strategies for individuals who live in H. pylori–prevalent areas.