Primary antibiotic resistance and its relationship with cagA and vacA genes in Helicobacter pylori isolates from Algerian patients

The epidemiology of Helicobacter pylori resistance to antibiotics is poorly documented in Africa and especially in Algeria. The aim of our study was to determine the antibiotic resistance rates, as well as its possible relationship with VacA and CagA virulence markers of isolates from Algerian patients. One hundred and fifty one H. pylori isolate were obtained between 2012 and 2015 from 200 patients with upper abdominal pain. Antimicrobial susceptibility testing was performed for amoxicillin, clarithromycin, metronidazole, ciprofloxacin, rifampicin and tetracycline. Molecular identification of H. pylori and the detection of vacA and cagA genes were performed using specific primers. We found that H. pylori was present in 83.5% of collected biopsies, 54.9% of the samples were cagA positive, 49.67% were vacA s1m1, 18.30% were vacA s1m2 and 25.49% were vacA s2m2. Isolates were characterized by no resistance to amoxicillin (0%), tetracycline (0%), rifampicin (0%), a high rate of resistance to metronidazole (61.1%) and a lower rate of resistance to clarithromycin (22.8%) and ciprofloxacin (16.8%). No statically significant relationship was found between vagA and cagA genotypes and antibiotic resistance results (p > 0.5) except for the metronidazole, which had relation with the presence of cagA genotype (p = 0.001).(AU)

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Background Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients. Methods DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8. Results The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA. Conclusions Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.(AU)

Interleukin 8 (-251 T>A) polymorphism in children and teenagers infected with Helicobacter pylori

Background Helicobacter pylori (H. pylori) is a gram-negative bacterium that colonizes the human stomach and causes a variety of gastric diseases. This study evaluated the correlations between the -251 (T>A) (rs4073) polymorphism of interleukin-8 (IL-8), the etiology of gastric disease, and H. pylori infection in pediatric and adolescent patients. Methods DNA samples were obtained from 285 gastric biopsies from pediatric patients. H. pylori was detected by PCR, whereas PCR-RFLP was used to characterize the -251 (T>A) polymorphism of IL-8. Results The histological analysis revealed the presence of gastritis in 158 patients (55.44%). H. pylori was found in 71 samples (24.9%). The -251 (T>A) polymorphism revealed that 58 (29.47%) samples were TT, 143 (50.18%) samples were TA, and 84 (20.35%) samples were AA. Conclusions Our findings suggest that IL8-251 A allele may be an important risk factor for the development of gastric disease when associated with H. pylori infection.(AU)

Helicobacter pylori with East Asian-type cagPAI genes is more virulent than strains with Western-type in some cagPAI genes

A gravidade da Helicobacter pylori relacionados com a doença está relacionada com a presença e a integridade de uma cag ilha de patogenicidade ( cag PAI). O genótipo de cag PAI pode ter um efeito modificador sobre o potencial patogênico da cepa infectante. Depois de analisar as seqüências de genes de cag PAI, algumas cepas com os genes PAI de cag do tipo do Leste Oriental foram selecionadas para análise posterior para examinar a associação entre a diversidade dos genes PAI cag e a virulência de H. pylori . Os resultados mostraram que a infiltração de células inflamatórias da mucosa gástrica foi significativamente maior em pacientes com genes PAI cag do leste asiáticoH. pylori estirpe em comparação com mosaicismo cag genes PAI H. pylori estirpe ( p <0,05). As cepas de H. pylori com os genes PAI do cag do tipo do Leste Asiático foram intimamente associadas à secreção de IL-8 in vitro e in vivo em comparação com cepas de H. pylori com os genes PAI do mosaicism cag ( p <0,01). As cepas de H. pylori com genes PAI cag do leste asiático são capazes de translocar fortemente CagA para células hospedeiras. Estes resultados sugerem que as cepas de H. pylori com cag do tipo East AsianOs genes PAI são mais virulentos do que as cepas do gene / genes PAI de CAG que são de tipo ocidental.(AU)

Investigation of Helicobacter pylori antigen in stool samples of patients with upper gastrointestinal complaints

Helicobacter pylori infection is usually acquired in early childhood and it can persist throughout life without antibiotic treatment. This study aimed to compare the accuracy of the noninvasive H. pylori Stool Antigen Test-applied on the stool samples with the invasive gold standart Rapid Urease Test-applied on the gastric biopy samples of patients with upper gastrointestinal complaints. After endoscopy, biopsy and stool specimens were taken in 122 patients. The infection was detected with rapid urease test which is accepted as gold standart test. Rapid, one-step H. pylori card test was applied to all patients stool specimens. In this study 106 of the 122 patients (86.8%) were positive for H. pylori infection, while 16 of the 122 patients (13.2%) were negative. H. pylori card test was negative in 13 of the 16 patients and was positive in 98 of the 106. The sensitivity, specifity, positive and negative predictive values were 92.45%, 81.25%, 97.02%, and 61.90%, respectively. H. pylori card test is rapid, easy, noninvasive and inexpensive methods for detection H. pylori infection. This test showed high sensitivity and specificity. Additionally, it may be a good alternative to invasive tests for the detection of H. pylori infections especially in children. (AU)

Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF-α gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α; was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-ΔΔCT). Results The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression. Conclusions Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α; pathway may play an important role in the progression from gastritis to gastric cancer(AU)

Prevalence of Helicobacter pylori in children in eastern Turkey and molecular typing of isolates

The objectives of the present study were to determine Helicobacter pylori via culture, polymerase chain reaction and histopathological diagnosis in 101 children ranging in age from 4 to 18 years, to identify the association among restriction fragment length polymorphism types and clinical disease and to investigate the relationships among different isolates of H. pylori in different age groups. We observed a high prevalence of H. pylori infections in children between the ages of 13 and 18 (75.8%), while children aged 4 to 6 years had the lowest prevalence of infection (40%). H. pylori was detected in 30.7% (31 of 101), 66.3% (67 of 101) and 63.2% (60 of 95) of children as determined by culture methods, PCR and histological examination, respectively. H. pylori isolates with RFLP types I and III were the most common among children with antral nodularity, whereas RFLP types II and IV were the least detected types. Interestingly, all isolates from peptic ulcer patients were type III. Although our results show a high prevalence of H. pylori infections in the pediatric population in eastern Turkey, no association was identified between H. pylori infection with antral nodularity and recurring abdominal pain. In addition, we found low genetic variation among H. pylori isolates from children and no association between RFLP types and antral nodularity (p > 0.05). Additionally, we found that H. pylori isolates with specific RFLP types were predominant in different age groups.(AU)

In vitro antagonistic activity of Lactobacillus casei against Helicobacter pylori

Helicobacter pylori is one of the most common causes of chronic infections in humans. Curing H. pylori infection is difficult because of the habitat of the organism below the mucus adherent layer of gastric mucosa. Lactobacilli are known as acid-resistant bacteria and can remain in stomach for a long time than any other organism, we aimed in this study to examine the efficacy of Lactobacillus casei as a probiotic against H. pylori in humans. Particularly, L. casei was opted as it is considered to be one of the widely used probiotics in dairy products. One hundred and seven strains of H. pylori were isolated from dyspeptic patients and were tested for their antibiotic susceptibility to metronidazole (MTZ), clarithromycin (CLR), tetracycline (TET), and amoxicillin (AMX) by the disc diffusion method. The strains were examined for their susceptibility toward L. casei - present in fermented milk products - by well diffusion method. It was found that 74.7% strains were resistant to MTZ; 1.8% to MTZ, TET, and CLR; 3.7% to MTZ and CLR; 4.6% to MTZ and TET; and 0.9% were resistant to MTZ, TET, and AMX. The antibacterial activity of L. casei against H. pylori was determined on all the tested H. pylori isolates including antibiotic resistant strains with different patterns. Our study proposed the use of probiotics for the treatment of H. pylori infection as an effective approach.(AU)

Lack of association among TNF-alfa gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF- gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61 and 73, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF- was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-CT). Results The analysis revealed an increase in TNF- gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF- gene expression. Conclusions Helicobacter pylori induces a large increase in TNF- expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF- pathway may play an important role in the progression from gastritis to gastric cancer.(AU)

Lack of association among TNF-alfa gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of theTNF- gene. Methods One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61 and 73, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF- was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2-CT). Results The analysis revealed an increase in TNF- gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF- gene expression. Conclusions Helicobacter pylori induces a large increase in TNF- expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF- pathway may play an important role in the progression from gastritis to gastric cancer.

Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.(AU)

Association among H. pylori virulence markers dupA, cagA and vacA in Brazilian patients

Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method.

Antimicrobial susceptibility testing for Helicobacter pylori isolates from Brazilian children and adolescents: comparing agar dilution, E-test, and disk diffusion

Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=-0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=-0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=-0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.

Virulence factors and antibiotic resistance of Helicobacter pylori isolated from raw milk and unpasteurized dairy products in Iran

Background Despite the high importance of Helicobacter pylori, the origin and transmission of this bacterium has not been clearly determined. According to controversial theories and results of previous studies, animal source foods especially milk play an important role in the transmission of H. pylori to humans. The aim of the present study was to determine the distribution of vacA, cagA,iceA and oipA virulence factors inH. pylori strains isolated from milk and dairy products and study their antimicrobial resistance properties. Methods A total of 520 raw milk and 400 traditional dairy product samples were cultured and tested. Those that were H. pylori-positive were analyzed for the presence of vacA,cagA, iceA and oip Avirulence factors. Antimicrobial susceptibility testing was performed by the disk diffusion method.Results One hundred and three out of 520 milk samples (19.8%) and 77 out of 400 dairy products samples (19.2%) were contaminated with H. pylori. The most frequently contaminated samples were ovine milk (35%) and traditional cheese (30%). Total prevalence ofvacA, cagA, iceA andoipA factors were 75%, 76.6%, 41.6% and 25%, respectively. H. pylori strains of milk and dairy products harbored high levels of resistance to ampicillin (84.4%), tetracycline (76.6%), erythromycin (70.5%) and metronidazole (70%). Conclusions High presence of antibiotic-resistant strains of H. pylorisuggest that milk and dairy samples may be the sources of bacteria that can cause severe infection. Our findings should raise awareness about antibiotic resistance in H. pylori strains in Iran.(AU)

Virulence factors and antibiotic resistance of Helicobacter pylori isolated from raw milk and unpasteurized dairy products in Iran

Background Despite the high importance of Helicobacter pylori, the origin and transmission of this bacterium has not been clearly determined. According to controversial theories and results of previous studies, animal source foods especially milk play an important role in the transmission of H. pylori to humans. The aim of the present study was to determine the distribution of vacA, cagA,iceA and oipA virulence factors inH. pylori strains isolated from milk and dairy products and study their antimicrobial resistance properties. Methods A total of 520 raw milk and 400 traditional dairy product samples were cultured and tested. Those that were H. pylori-positive were analyzed for the presence of vacA,cagA, iceA and oip Avirulence factors. Antimicrobial susceptibility testing was performed by the disk diffusion method.Results One hundred and three out of 520 milk samples (19.8%) and 77 out of 400 dairy products samples (19.2%) were contaminated with H. pylori. The most frequently contaminated samples were ovine milk (35%) and traditional cheese (30%). Total prevalence ofvacA, cagA, iceA andoipA factors were 75%, 76.6%, 41.6% and 25%, respectively. H. pylori strains of milk and dairy products harbored high levels of resistance to ampicillin (84.4%), tetracycline (76.6%), erythromycin (70.5%) and metronidazole (70%). Conclusions High presence of antibiotic-resistant strains of H. pylorisuggest that milk and dairy samples may be the sources of bacteria that can cause severe infection. Our findings should raise awareness about antibiotic resistance in H. pylori strains in Iran.

Virulence factors and antibiotic resistance of Helicobacter pylori isolated from raw milk and unpasteurized dairy products in Iran

Background Despite the high importance of Helicobacter pylori, the origin and transmission of this bacterium has not been clearly determined. According to controversial theories and results of previous studies, animal source foods - especially milk - play an important role in the transmission of H. pylori to humans. The aim of the present study was to determine the distribution of vacA, cagA,iceA and oipA virulence factors inH. pylori strains isolated from milk and dairy products and study their antimicrobial resistance properties.Methods A total of 520 raw milk and 400 traditional dairy product samples were cultured and tested. Those that were H. pylori-positive were analyzed for the presence of vacA,cagA, iceA and oipAvirulence factors. Antimicrobial susceptibility testing was performed by the disk diffusion method.Results One hundred and three out of 520 milk samples (19.8%) and 77 out of 400 dairy products samples (19.2%) were contaminated with H. pylori. The most frequently contaminated samples were ovine milk (35%) and traditional cheese (30%). Total prevalence ofvacA, cagA, iceA andoipA factors were 75%, 76.6%, 41.6% and 25%, respectively. H. pylori strains of milk and dairy products harbored high levels of resistance to ampicillin (84.4%), tetracycline (76.6%), erythromycin (70.5%) and metronidazole (70%).Conclusions High presence of antibiotic-resistant strains of H. pylorisuggest that milk and dairy samples may be the sources of bacteria that can cause severe infection. Our findings should raise awareness about antibiotic resistance in H. pylori strains in Iran.(AU)

Diagnosis of Helicobacter pylori infection by invasive and noninvasive tests

Although several invasive and noninvasive tests have been developed for the diagnosis of Helicobacter pylori infection, all of the tests have their limitations. We conducted a study to investigate and compare the suitability of rapid urease test (RUT), serology, histopathology and stool antigen tests with polymerase chain reaction (PCR) for detection of H. pylori, and correlate the diagnostic methods with PCR. Eighty nine patients (61 adults, 28 children) referred to the Firoozgar Hospital and Children Medical Center Hospital for diagnostic upper gastrointestinal endoscopy entered to the study and noninvasive tests such as immunoassay for serological antibodies against H. pylori and detection of its antigen in feces were measured. The biopsies were utilized for histological examination, RUT and PCR. The H. pylori statuses were evaluated by the positivity of ureC PCR in biopsy specimens and 53 subjects had H. pylori positive result. Histopathology showed high overall performance in adults and children with sensitivity and specificity 100% and 90%, respectively. Sensitivity, specificity, and accuracy for stool antigen test were 87.8%, 75% and 82%, respectively. Correlation of RUT, serology (IgG), histopathology and stool antigen tests with PCR were 0.82, 0.32, 0.91 and 0.63, respectively. In conclusion, the RUT and histopathology are as accurate as the PCR of biopsy and stool antigen test can consider as appropriate noninvasive test for detection of H. pylori infection.(AU)

Prevalence of genotypes in Helicobacter pylori isolates from patients in eastern Turkey and the association of these genotypes with clinical outcome

There is not much information available regarding the prevalence of the genotypes of Helicobacter pylori isolates in Turkey, particularly in eastern Turkey. The aims of this study were to detect the prevalence of different genotypes of H. pylori in Turkish patients with gastrointestinal complaints and to determine the relationship of these genotypes with clinical outcome and sex. One hundred forty H. pylori isolates were examined for the presence of its genotypes by the PCR. We found that the prevalence of vacA s1, vacA s2, cagA, cagE, iceA1, iceA2 and babA2 genes were 88.6%, 11.4%, 71.4%, 35.7%, 41.4%, 58.6%, and 62.1%, respectively. The most predominant vacA subtype was s1a (81.4%). The most vacA allelic combination detected were vacA s1m1 (65.2%)and s1m2 (53.9%) in patients with peptic ulcer and gastritis, respectively. The only vacA s1 isolate was significantly associated with gastritis and peptic ulcer (p<0.05). The vacA s1a, ml, slml and babA2 genes were significantly associated with peptic ulcer (p<0.05), whereas m2 gene was significantly associated with only gastritis (p<0.05). The difference between sex and genotypes was statistically significant among the cagA, vacA s1, iceA2 and babA2 genes. This study reported for the first time the prevalence of H. pylori genotypes in patients with gastrointestinal complaints in eastern Turkey. Further studies are needed to understand epidemiological importance of the genotypes of H. pylori isolates in this region and the association between the virulence genes and clinical outcome in different regions.(AU)

Detection of Helicobacter pylori in gastric biopsies, saliva and dental plaques of dyspeptic patients from Marília, São Paulo, Brazil: presence of vacA and cagA genes

Helicobacter pylori, a gram-negative bacterium, possesses two important virulence factors: the vacuolating toxin (vacA), and the cytotoxin-associated gene product (cagA). The aim of the present study was to evaluate the presence of H. pylori in the stomach and oral cavity of humans and compare the cagA and vacA genotypes of H. pylori found in different samples (stomach, saliva and dental plaque) from the same patient. Gastric biopsies, saliva and dental plaques were obtained from 62 dyspeptic adults. DNA was extracted and evaluated for the presence of H. pylori and the alleles cagA and vacA. Persons with gastritis had a higher frequency of H. pylori -positive samples in the stomach while positive samples from gastric biopsies were significantly correlated with those from the oral cavity. There was a high H. pylori frequency in patients while the cagA gene was associated with vacA s1 alleles in gastric biopsies. Our results suggest a reservoir of the species in the oral cavity and that, in one patient, more than one H. pylori strain may exist in the saliva, dental plaque and stomach. We found a relationship between gastric infection and the bacterium in the oral cavity, with the cytotoxin genotype varying between saliva and dental plaque.(AU)

Relationship between Helicobacter pylori detection and an increased risk of infection in childhood

The risk of developing gastric cancer is believed to be related to differences among Helicobacter pylori strains and the inflammatory responses mediated by host genetic factors. H. pylori infection is acquired at an early age and in the absence of appropriate antibiotic therapy, it generally persists for life. Tp53 gene regulates the transcription of several cytokines and chemokines involved in innate immunity and its action may be influenced by the presence of different H. pylori strains. The present study aimed to detect H. pylori in pediatric patients, to access Tp53 polymorphism at codon 72 and to correlate such findings with age and histopathological results. Three hundred and forty-two patients were analyzed. DNA from their gastric biopsies was extracted and the detection of H. pylori was performed through polymerase chain reaction assays, urease test and histopathologic examination. Allelic discrimination of SNP rs1042522 (Tp53) was performed by real-time polymerase chain reaction. Our results suggest a possible relationship between the presence of H. pylori and chronic gastritis in children and young patients, and showed a significant association between ageing and positivity for H. pylori. It was verified that patients aged < 10 years were 1.3 times more likely to have infection by H. pylori when compared with those aged > 10 years. Finally, no association was found between Tp53 polymorphisms and the presence of H. pylori.(AU)