cagA positive Helicobacter pylori in Brazilian children related to chronic gastritis

Abstract

Helicobacter pylori is a spiral-shaped Gram-negative bacterium. It colonizes the gastric mucosa of humans and persists for decades if not treated. Helicobacter pylori infection affects more than half of the world's population and invariably results in chronic gastritis. The cagA gene is present in about 60 to 70% of H. pylori strains; it encodes a high-molecular-weight protein (120 to 140 kDa) and several investigators have noted a correlation between strains that possess cagA and the severity of gastric mucosal inflammation. We examined the relation between cagA status in H. pylori strains and chronic gastritis with inflammatory processes in children from Marília, São Paulo, Brazil. Onehundred-twenty-one children were analyzed histopathologically and by polymerase chain reaction (PCR) to detect H. pylori and cagA. We then looked for an association between cagA presence and inflammatory infiltration. Using histology and PCR, we found 47% H. pylori positive infection; 29 children were diagnosed with chronic gastritis, while 28 showed normal mucosa by histopathological analysis. CagA presence was genotyped in both groups, and an inflammatory infiltrate was studied in all infected children with chronic gastritis. We found cagA strains in 20 of 29 (69%) children with chronic gastritis and 18 of 28 (64%) with normal mucosa, demonstrating a strong relationship between the strains and the inflammatory process. We found a positive association between an inflammatory process associated with H. pylori of cagA+ strains and chronic gastritis development.

ABO blood groups and Helicobacter pylori cagA infection: evidence of an association

“…The rate of infection by this strain reported herein is similar to previous Brazilian studies of adult and infant populations published in recent years (6)(7)(8).…”

“…Brazilian patients suffering from various gastroduodenal diseases (6)(7)(8). The cagA virulence factor seems to be involved in the induction of proinflammatory chemokines expressed by host cells and plays a notable role in the onset and progression of gastroduodenal diseases (2,9).…”

“…pylori infections by strains carrying the cagA, vacA, iceA and babA2 genes were observed among Brazilian adults and children suffering from gastroduodenal diseases (6)(7)(8)18 America (21). Therefore, the consequent acquisition of babA2 and cagA genes would allow the H. pylori bacillus to adapt based on the prevalent ABO blood groups in South America (10).…”

High Prevalence of Clarithromycin Resistance and cagA , vacA , iceA2 , and babA2 Genotypes of Helicobacter pylori in Brazilian Children

“…Metronidazole, amoxicillin, and tetracycline resistance was also studied. Furthermore, the study aimed to genotype the vacA and iceA genes and to detect the cagA gene in gastric biopsy specimens, since recent studies found a high frequency of cagA-positive and iceA2-positive strains as well as a strain with the vacA signal region genotype s1 and middle region sequence m1 among pediatric H. pylori isolates in Brazil (6,7,11,23). This is also the first investigation of babA2 gene prevalence in Brazilian children.…”

Clinical Evaluation of Triple and Quadruple Helicobacter Pylori Eradication Therapy in Peptic Ulcer Patients With Different Abo Blood Group Phenotypes

“…Furthermore, other studies revealed that high rates of infection by cagA-positive H. pylori strain were in patients belonging to the blood Group O phenotypes [6,42]. Moreover, infection with cagA-positive H. pylori strains induces a marked inflammatory response, with a great density of polymorphonuclear cells in the gastric mucosa and high levels of serum TNFα and gastrin, which were seen as markers of inflammation in H. pylori infection, when compared with the cagA-negative strains [43,44]. In Brazilian population, an association between cagA and severe inflammation was noticed in patients with DU and gastric carcinoma [45,46].…”