Prospective multicentre study on antibiotic resistance of Helicobacter pylori strains obtained from children living in Europe.

AIM: To prospectively assess the antibacterial resistance rate in Helicobacter pylori strains obtained from symptomatic children in Europe. METHODS: During a 4-year period, 17 paediatric centres from 14 European countries reported prospectively on patients infected with H pylori, for whom antibiotic susceptibility was tested. RESULTS: A total of 1233 patients were reported from Northern (3%), Western (70%), Eastern (9%) and Southern Europe (18%); 41% originated from outside Europe as indicated by mother's birth-country; 13% were <6 years of age, 43% 6-11 years of age and 44% >11 years of age. Testing was carried out before the first treatment (group A, n = 1037), and after treatment failure (group B, n = 196). Overall resistance to clarithromycin was detected in 24% (mean, A: 20%, B: 42%). The primary clarithromycin resistance rate was higher in boys (odds ratio (OR) 1.58; 1.12 to 2.24, p = 0.01), in children <6 years compared with >12 years (OR 1.82, 1.10 to 3.03, p = 0.020) and in patients living in Southern Europe compared with those living in Northern Europe (OR 2.25; 1.52 to 3.30, p<0.001). Overall resistance rate to metronidazole was 25% (A: 23%, B: 35%) and higher in children born outside Europe (A: adjusted. OR 2.42, 95% CI: 1.61 to 3.66, p<0.001). Resistance to both antibiotics occurred in 6.9% (A: 5.3%, B: 15.3%). Resistance to amoxicillin was exceptional (0.6%). Children with peptic ulcer disease (80/1180, 6.8%) were older than patients without ulcer (p = 0.001). CONCLUSION: The primary resistance rate of H pylori strains obtained from unselected children in Europe is high. The use of antibiotics for other indications seems to be the major risk factor for development of primary resistance.

IgG subclass response to Helicobacter pylori and CagA antigens in children.

Specific serum IgG subclass antibodies against Helicobacter pylori antigens and recombinant CagA were analysed in 75 symptomatic children with histologically confirmed H. pylori infection. H. pylori stimulated an IgG1 predominant response, and IgG3 titres showed a positive association with peptic ulcer disease, chronicity of antral inflammation and density of H. pylori colonization. Two methods used for assessing serum IgG CagA antibody status, i.e. Western blotting and enzyme-linked immunosorbent assay (ELISA), were concordant. CagA stimulated an IgG1 and IgG3 predominant humoral response. Total CagA IgG titres were higher in children with active and more severe chronic antral inflammation. These findings suggest that in children the systemic humoral immune response to H. pylori infection may reflect gastroduodenal pathology.

Primary resistance to clarithromycin in clinical strains of Helicobacter pylori isolated from children in Poland.

Helicobacter pylori resistance to clarithromycin is an important factor in the failure of eradication therapy. The resistance results from point mutations in the 23S rRNA gene of H. pylori. The prevalence of primary resistance of H. pylori to clarithromycin in children and mutations associated with resistance were studied and it was found that 23.5% (23/98) of H. pylori strains isolated in our hospital during 1998-2000 were resistant to clarithromycin. The primary resistance was mainly caused by an A2143G mutation, but the isolates with an A2142G mutation had higher MICs for clarithromycin compared with those with an A2143G mutation: median MIC 256 versus 16 mg/l. Comparison of our data with previous results showed that the prevalence of H. pylori resistance to clarithromycin in children has increased in Poland over the last three years, however the difference was not significant (23.5 vs. 17%, P=0.22).

PCR-based diagnosis of Helicobacter pylori infection in Polish children and adults.

Infection and associated disease caused by Helicobacter pylori are common in Poland, as in much of Eastern Europe, although the genotypes of strains have not been much studied, especially in terms of traits that might be important in disease. This study developed a sensitive and efficient polymerase chain reaction (PCR) test for the presence of H. pylori in gastric biopsy samples with ureA gene-specific primers and primers for the virulence-associated cag pathogenicity island (PAI). These tests were used with biopsy samples from 246 symptomatic children (age range 1-17 years) and 82 adults (age range 18-53 years) in Warsaw. An assessment was also made of the success of metronidazole-based therapy intended to eradicate infection. H. pylori was detected by ureA-specific PCR in 83 (76.9%) children and in 41 (87.2%) adults with histologically proven gastritis, and in 28.4% and 29.2%, respectively, of the 38 children and 7 adults with little or no evidence of gastritis. In general, H. pylori was detected more often by PCR than by culture (70.3% compared with 52.8% in children and 62.8% compared with 38.6% in adults), although in several cases a negative PCR was associated with a positive culture result. The rate of H. pylori infection increased with age from 5.4% in children up to 5 years old to 29.2% to age 10 and 65.4% to age 18. The tests detected the cagPAI in 97 (75%) and 44 (85%) of the H. pylori-infected children and adults, respectively. Some H. pylori-infected patients with a ureA+ PCR result contained the 'empty site' of the cagPAI and only four patients were infected with mixed cag+ cag- strains. PCR with cagPAI and 'empty site' of the cagPAI represents a novel tool for fast screening of mixed cag+ cag- infection. These results confirm and further illustrate that direct PCR of biopsy specimens can be useful for detection of infection and genotyping of resident strains, and that H. pylori infection is very common among children as well as adults in Poland. They also show that Polish strains vary with regard to the presence or absence of the cagPAI, and suggest that the proportion of strains that are cag+ is higher in Poland than in Western European countries, which may reflect the relatively higher risk of infection in this society.

Genotypes of Helicobacter pylori in Polish population.

Here we have studied the genetic diversity of Helicobacter pylori strains recovered from 64 individual patients, 5 family members and 13 unsuccessfully treated patients. The recovered bacteria were finger-printed by the PCR-RFLP and RAPD methods and virulence associated loci (cagPAI, vacA) were PCR studied. Unique differentiation of every independently isolated strain from not-related persons was possible by RAPD technique. In PCR-RFLP technique several profile groups (7 and 15) for particular endonuclease tested were found. Eleven patients carried strains of the same gene profile (PCR-RFLP) and the same overall genotype (RAPD) before and after therapy. In the family studies, essentially the same strain was found in different relatives in three cases, and different strains were found in the other two cases. Island of cagPAI was present in 79% of all strains tested, half and one-fifth of all strains tested presented, s1am2 and s1m1 alleles of vacA gene, respectively. Independently from identity or diversity of pre- and post-treatment strains and strains recovered from the family members we have been observed identical cagPAI/vacA genotypes. These results suggest that H. pylori infections in Poland can be mixed, although just one strain may often predominate, and that inter-family transmission may be significant even in this high risk society. The genetic feature of virulence-associated loci are similar to those seen elsewhere in Europe, although strains that carry the cagPAI and the potentially more toxigenic alleles of the vacA gene are more common. RAPD technique is proven as most differentiating, however PCR-RFLP allows for easy recognition of mixed infection with two or more different strains. Molecular typing study in case of children therapy may allow reduce rate of relapses by reduction of possible transmission from family source.

PCR for identification and typing of Helicobacter pylori isolated from children.

From 191 children with upper gastroduodenal disease 236 gastric biopsy specimens were taken. H. pylori was detected by use of culture Gram staining histological examination and PCR technique. A segment of DNA coding protein synthesis of 26 kDa or urease A and B gene were used for PCR amplification. PCR technique was also used for determination of the presence of Cag A gene in 72 strains of H. pylori isolated from children. Genetic typing of H. pylori strains by RFLP analysis of PCR amplified urease B gene 933 bp fragment and RAPD were performed. Biopsy specimens taken from children with gastritis were in 52% H. pylori culture and PCR positive, while 18.1% PCR positive only. Similarly, specimens taken from children with duodenal ulcer were in 50% H. pylori culture and PCR positive, while 12.5% PCR positive only. Fifty one (70.8%) from 72 strains of H. pylori were Cag A positive. Molecular typing of the strains isolated during first and follow-up endoscopy allowed the differentiation between reinfection or new infection and coinfection. It was shown that RAPD typing had better discrimination power in comparison to PCR--RFLP method.

[Esophageal achalasia in children (analysis of five cases)]. / Achlazja przelyku u dzieci (analiza pieciu przypadków).

Oesophageal achalasia is a disease of middle age and is only exceptionally observed in children. Five patients aged from 6.5 to 14 years were treated for this achalasia. Routine therapeutic method was repeated pneumatic dilatation of the cardia with a Rider-Moeller dilator. In all, 33 such procedures were carried out without complications. Very good results were obtained in 2 cases already after 3 dilatation procedures. The remaining 3 cases required surgical intervention: in 2 of them esophagomyotomy with antireflux operation was done with a very good result in one case and a good result in another case. The child not treated surgically (lack of parental consent) has still most signs of achalasia with body weight below the 3 centile and with recurrent respiratory infections. The follow-up is from 5 to 66 months.

Campylobacter pylori in upper digestive tract diseases in children.

Results of studies on the frequency of the occurrence of the bacteria, Campylobacter pylori, in the mucous membrane of the gastric antrum are presented in this paper. The study was carried out on 61 children treated for chronic abdominal pain. The diagnosis was established on the basis of flexible endoscopy and histology of antral biopsies. The presence of Campylobacter pylori was determined using the CLO-test. The positive CLO-test was obtained in 87.5% of children with gastritis, in 75% of children with duodenal ulcer and in only 17% of children from control group (p less than 0.001). Four-week therapy with De Nol eradicated Campylobacter pylori in 60% of treated children, and reduced infection in the next 25%. These bacteria seem to play an important role in the pathogenesis of chronic gastritis and peptic ulcer disease.

[Fiber-optic endoscopy of the lower gastrointestinal tract in children]. / Fiberoskopia dolnego odcinka przewodu pokarmowego u dzieci.

Between 1978 and 1985 565 lower gastrointestinal endoscopies were performed in children. In 221 cases the cause of rectal bleeding was explored, in 227 the suspicion of colitis and in 25 of polyposis was verified. To evaluate the results of treatment (polypectomy, surgical procedures and medical therapy in inflammatory bowel disease) 121 examinations were done. With increasing experience the complete colonoscopy was performed more often. In 1985 coecum and ileum terminale was reached in almost all children in whom it was needed (75% of all examinations). The inflammatory changes were revealed on 230 occasions. In 78 cases colon polyps and in 27 vascular changes were found. The most common cause rectal bleeding were colon polyps (66 cases) and inflammatory changes (554 cases). Less common were vascular changes (10 cases). 32% false negative and 16% false positive results of colonoscopy in diagnosis colitis were obtained when the results of visual findings were compared with histopathological findings. Colonoscopy performed by an experienced colonoscopist rather avoiding general anesthesia is a safe and useful procedure in diagnosing lower gastrointestinal tract diseases in children. The evaluation of colitis should be based on visual findings with biopsy confirmation.

[Barrett esophagus]. / Przelyk Barretta u dzieci.

An analysis of the clinical picture of Barrett's esophagus in 18 children is presented. This group of patients have been distinguished out of 114 children with chronic gastroesophageal reflux on the base of anatomopathological examinations. Clinical course and efficiency of the diagnostic examinations depend on the degree of esophagitis. They are slightly characteristic in children with minimal lesions. Long-term follow up - necessary due to the risk of cancer - have shown that there is possibility of recovery in cases of minimal advancement and short duration of the disease.