Tài liệu Epidemiological and clinical characteristics and outcomes of treatment regimens for pediatric peptic ulcer disease caused by drugresistant helicobacter pylori at national pediatric hospital

1 MINISTRY OF EDUCATION AND MINISTRY OF TRAINING HEALTH NATIONAL INSTITUTE OF HYGIENE AND EPIDEMIOLOGY NGUYEN THI UT EPIDEMIOLOGICAL AND CLINICAL CHARACTERISTICS AND OUTCOMES OF TREATMENT REGIMENS FOR PEDIATRIC PEPTIC ULCER DISEASE CAUSED BY DRUGRESISTANT HELICOBACTER PYLORI AT NATIONAL PEDIATRIC HOSPITAL Specialty: Epidemiology Code: 62.72.01.17 SUMMARY OF MEDICINE PHD THESIS HANOI – 2016 2 This work has been completed at the National Institute of Hygiene And Epidemiology Instructors: 1. Le Thanh Hai, Associate Professor, Ph.D 2. Hoang Thi Thu Ha, Ph.D Reviewer 1: Hoang Huy Hau, Associate Professor, Ph.D. Reviewer 2: Nguyen Gia Khanh, Professor, Ph.D Reviewer 3: Pham Van Trong, Associate Professor, Ph.D The Thesis will be defended at the Institute level Council for Thesis Performance Appraisal convened at the National Institute of Hygiene And Epidemiology. On: date month year 2016 The Thesis could be found at: 1. The National Library 2. The Library, National Institute of Hygiene And Epidemiology 3 1. INTRODUCTION Peptic ulcer disease (PDU) caused by Helicobacter pylori (H. pylori) was a rather common condition in the world. H. pylori had been considered a major cause of chronic gastritis (77.4 77.9%); duodenal ulcer (>95%) and stomach ulcer (>75%). Treatment of H. pylori PDU was difficult, and treatment regimen outcomes depended very much on antibiotics - provided with high drug resistance, treatment effectiveness used to be lower than desired levels (<80%). Understanding of H. pylori PDU epidemiological and clinical characteristics, and therapeutic antibiotic efficacy could help clinicians and managers act more effectively in prevention and treatment. So far, in Vietnam, there had not been any study on H. pylori epidemiological, clinical and toxicological characteristics; and effectiveness of treatment for pediatric PDU caused by drug-resistant H. pylori. Therefore, we carried out the research on “Epidemiological and clinical characteristics and outcomes of treatment regimens for pediatric peptic ulcer disease caused by drug-resistant Helicobacter pylori at National Pediatric Hospital, October 2011 to November 2013”. Specific objectives of the research were: 1. Epidemiological and clinical characteristics of pediatric peptic ulcers disease caused by drug-resistant H. pylori at National Pediatric Hospital, from October 2011 to November 2013, described. 2. Drug resistance levels and related factors in children with PDU determined. 3. Drug-resistant H. pylori clearance effects of some treatment regimens for pediatric PDU cases described. 4 2. NEW SCIENTIFIC CONTRIBUTIONS  This was one of comprehensive researches on epidemiology, clinical features and treatment of drug-resistant H. pylori PDU in children, Vietnam, with a relatively large number of pediatric patients.  The research had used molecular biology techniques, namely PCR and RAPD to identify toxic genes of bacteria, and the transmissibility in the family.  This was one of researches that simultaneously used both 4 drug and 3 drug treatment regimens to treat pediatric H. pylori PDU. 3. PRACTICAL VALUES OF THE THESIS - Results on epidemiological and clinical characteristics of drugresistant pediatric H. pylori PDU helped physicians visualize its drug resistance. Disease related information orientated them to PDU. - The research had also found 4 drug treatment regimen effective and safe in the treatment of drug-resistant H. pylori PDU. 4. THESIS STRUCTURE The thesis included 146 pages: introduction (2 pages), overview (45 pages), research subjects and methodology (20 pages), results (37 pages), discussion (39 pages), conclusion (2 pages), and recommendation (1 page), with 42 tables, 5 figures, 18 charts, and 219 reference documents including 24 Vietnamese and 195 English ones. CHAPTER 1: OVERVIEW 1.1. PDU epidemiological and clinical characteristics, and drug-resistant H. pylori 5 1.1.1. Definition: Gastritis is a term referring to all inflammatory lesions in the gastric mucosa, demonstrating response of the gastric mucosa to attacking elements. Gastro-duodenal injuries when deeply impregnated through the muscular layer of stomach or duodenal membranes would lead to ulcers. 1.1.2. H. pylori research history In 1984, H. pylori was successfully isolated by Marshall and Warren; this finding had been official published in The Lancet (1984). Recently, the role of H. pylori in PDU pathogenesis, its antibiotic resistance, and treatment regimens had been mentioned in many international and national conferences. 1.1.3. H. pylori PDU epidemiological characteristics 1.1.3.1. Etiology and transmission sources H. pylori is a gram-negative bacterium with helical shape. It is a major cause of active chronic gastritis and gastric ulcers, and a risk for gastric cancer. H. pylori transmission source is mainly human being. 1.1.3.2. Modes of transmission - Mouth-to-mouth, fecal-oral, gastro-oral transmission routes. - Family transmission was found by many studies. 1.1.3.3. Susceptible population H. pylori could co-exist with the host for decades without symptoms. Once infected with H. pylori, patients may suffer from gastritis, stomach ulcers, and stomach cancer. 1.1.3.4. Disease frequency Frequency of H. pylori PDU varies very much from country to country and from age group to age group. Generally it is higher in developing countries and lower in developed countries. 6 Incidence of gastroenteritis is age dependent. PDU is a problem of 1-1.5% children; it is often primary, mostly chronic and localizes in the duodenum; its main cause is H. pylori infection (about 80%) or unknown (about 20%). About 10 to 15% people infected with H. pylori would develop PDU and 1% would develop stomach cancer. 1.1.4. Pathogenesis In the acute phase, bacteria invade, multiply and cause mucosal inflammation. In the chronic inflammatory phase, manifestation is clear with tissue changes, peeling mucosa and multiple inflammatory cell infiltration; mucosal barrier is destroyed, leading to scratches and ulcers. 1.1.5. Immunology After being infected with H. pylori, the host would develop a very strong local and systemic immune response. Despite of this immune response, infection may still exist throughout the life. 1.1.6. Clinical manifestations H. pylori infection could lead to symptoms in the gastrointestinal tract or digestive system. Recurrent abdominal pain is a common clinical sign – up to 87-96%; abdominal pain could be localized in the epigastric region, or persists around the navel and is associated with meals. Nausea and vomiting are two common signs in children under 3 years old. Older children often suffer from gnawing, shortness of breath, bloating and discomfort. Peptic ulcer: H. pylori infected children often have no symptom; only a small portion develops ulcerative PDU. H. pylori is found in 90% of children with ulcerative PDU, and it is 7 proved that ulcers would be healed after H. pylori clearance. 1.1.7. Methods of diagnosing H. pylori PDU 1.1.7.1. Diagnostic methods  Non-invasive methods + Serological test: mainly applied for epidemiological studies. + Breath test (UBT): allows determining H. pylori infection based on bacterial urea hydrolysis. Carbon marking could use C13. + Stool antigen test: accuracy of the test using monoclonal antibodies is higher than of polyclonal antibodies. • Invasive methods + Endoscopy: to determine H. pylori gastritis through images - normal; inflammation; nodules with lumpy granular; new, still bleeding shallow scraped or deep ulcers; or old and scarring ulcers. + Rapid urease test (CLO test): allows determining the presence of H. pylori. + Histopathology: helps detect bacteria and evaluate peptic mucosal lesions + Bacterial culture Culturing is considered the gold standard method with 100% specificity. Culturing verifies and identifies H. pylori antibiotic resistance. + H. pylori antibiotic susceptibility test: - Diffusion test: suspension of 108 CFU / ml bacteria cultured in the Mueller – Hinton agar media containing 10% horse blood, then put standardized antibiotic paper discs on its surface. Results 8 are calculated following diameter of the sterile round generated. + Molecular biology methods PCR method amplifies duplicate strings, helps determine the presence of bacterial toxic genes such as cagA and vacA. RAPD (Random Amplified polymorphic DNA) – a method for multifold analysis of randomly amplified DNA. RAPD helps identify differences between different bacterial strains. Genomes of two different strains give different footages on the genes for comparison of bacteria’s biodiversity. 1.1.7.2. Diagnosis of H. pylori PDU  Criteria for H. pylori PDU diagnosis: + Endoscopy test is used to diagnose peptic ulcer according to Sydney classification system. + Histopathological test is used to diagnose gastritis. H. pylori infection is diagnosed when present one of the following conditions: - H. pylori (+) in histopathological and urease tests. - H. pylori (+) in culture of gastric biopsy piece. 1.2. Antibiotic-resistant H. pylori and risk factors of PDU 1.2.1. Concept of antibiotic resistance 1.2.1.1. H. pylori primary antibiotic resistance This is the status when a child has not been previously treated for clearing H. pylori; antibiotic resistance is the consequence of using antibiotics to treat his/her other diseases. A small number of patients received drug-resistant strains from others. 1.2.1.2. H. pylori secondary antibiotic resistance 9 This is the status when H. pylori antibiotic resistance appears in patients who have been previously treated for H. pylori clearance. 1.2.2. Antibiotic resistance and virulence of bacteria 1.2.2.1. VacA gene related cytotoxic factors VacA is an important toxin presented in almost all strains of H. pylori. VacA contains diverse alleles that vary from one to other H. pylori strain. VacA genotype s1 / m1 is the most toxic combination, while s2 / m2 and m2 / s1 are nontoxic. 1.2.2.2. CagA gene related cytotoxic factors CagA is a toxic protein of H. pylori, encoded by cagA gene. CagA (+) is more often associated with peptic ulcer, atrophic hypertrophic gastritis and adenocarcinoma than strains cagA (-). Taneike had found that 68% strains contained cagA (+), metronidazole resistance rates among cagA (-) group was higher than of cagA (+) (P = 0.0089). 1.2.3. H. pylori antibiotic resistance rate and risk factors - H. pylori antibiotic resistance is the main cause of treatment failure. Worldwide, antibiotic resistance rate is increasing and varies from region to region. Developing countries faces a higher antibiotic resistance rate than developed ones. This rate of clarithromycin is > 20% in the US and other developed countries in Europe and Asia. 1.2.5.1. Clarithromycin resistance rate Clarithromycin resistance rate among children is 50.9% in Vietnam. 1.2.5.2. Azithromycin resistance rate 10 Azithromycin resistance ranges is high in children; it varies from 17.9% in Croatia to 87.7% in Beijing. 1.2.5.3. Metronidazole resistance rate In Vietnamese children, metronidazole resistance rate is 65.3%; this is increased with age, higher in urban than in rural areas, and more common in boys. 1.2.5.4. Amoxicillin resistance rate In Europe, resistance rate is low at 0-2%. However, high rate had been seen in some countries of Africa and Asia – among children of Iran it was 59%. In Vietnam, the rate of 2006 was 0.5%. 1.2.5.5. Tetracycline resistance rate Tetracycline resistance has not been seen, or seen at very low rate in most countries (0-5%). The rate among Italian and Bulgarian children was 3%. 1.2.5.6. Quinolone resistance rate Primary resistance rate in children is low (2-7%). High resistance usually involves increased use of new quinolone generations. Ciprofloxacin primary resistance in Italian children in 2005 accounted for 6%. Levofloxacin resistance among Beijing children was rather high - 13.7%. 1.2.5.8. Resistance to two or more antibiotic classes Rate of resistance to two antibiotics classes is <10% in Europe, Asia and North America. Rate of resistance to both amoxicillin and clarithromycin among children of Iran is 14.5%. This rate for both clarithromycin and metronidazole among children of Vietnam is 28.8%. 1.3. Treatment of H. pylori PDU 11 1.3.1. Indications for treatment Antibiotic treatment is applied to all H. pylori (+) PDU; children with endoscopy diagnosed lesions and H. pylori (+) whose father/mother had H. pylori ulcers/stomach cancer; children with iron deficiency anemia who are not successful with treatment, or with autoimmune thrombocytopenia. 1.3.2. Treatment drugs 1.3.2.1. Secrete preventing drugs Proton pump inhibitors (PPI) Omeprazole: Rapidly and effectively inhibits acid after an oral dose. 1.3.2.2. Antibiotics Amoxicillin: is an antibiotic that effectively clears H. pylori by destroying bacterial cell walls, leading to its destruction. Metronidazole: is an osmotic drug that enters bacterial cells and causes its DNA damage, thus destroys it. Clarithromycin: impacts on transfer RNA and 50S ribosomal subunit, disordering bacterial protein synthesis, thus destroys it. Bismuth salt: This has a direct bactericidal effect thanks to the agglomeration of crystals inside and on the bacterial cell walls, condensing bacterial cell vacuoles. CHAPTER 2 RESEARCH SUBJECTS AND METHODOLOGY 2.1 Research Subjects 2.1.1 Research Subjects Pediatric patients 2 to 16 years old diagnosed with H. pylori PDU, examined and treated at the National Institute of Pediatrics 12 from October 2011 to November 2013. 2.1.2. Inclusion criteria Patients meeting the following criteria: - Clinical: symptoms of gastroduodenal pathology, indicated for gastrointestinal endoscopy, including recurrent abdominal pain, nausea, vomiting, bloating, indigestion and epigastric burning or gastrointestinal bleeding, and unexplained anemia. - Testing: + Endoscopy: images of inflammatory lesions or peptic ulcers + Histopathology: patients with inflammatory lesions + Bacterial culture: growth and antimicrobial susceptibility obtained - Treatment: Patients who have not been treated with antibiotics, proton pump inhibitors and antacids within 1 month before being undergone endoscopy; and have no history of PDU treatment. - Families and patients agree to participate in the research with full adherence; and to come for check ups on time. 2.1.3. Exclusion criteria - Patients with other infections and serious illnesses. - Patients having undergone gastric operation(s) and been allergic to antibiotics. 2.2. Research sites - Epidemiological and clinical studies performed at the Department of Gastroenterology; and Outpatient Clinics – National Pediatric Hospital. - Paraclinical studies performed at the Department of 13 Bacteriology - National Institute of Hygiene and Epidemiology, and Departments of Endoscopy and of Pathology - National Pediatrics Hospital. 2.3. Research time From October 2011 to November 2013. 2.4. Research Methodology 2.4.1. Design: 2 designs used - Cross-sectional descriptive study with appropriate analysis - Treatment assay without control groups, describing results of 2 treatment regimens. 2.4.2. Sample size and sampling method 2.4.2.1 Sample size and sampling method for Objectives 1 and 2 + Sample size: total patients meeting inclusion criteria during 2 years, from October 2011 till November 2013. To respond to the 1st Objective, 588 eligible children diagnosed with PDU caused by antibiotic-resistant H. pylori were enrolled in the research. For the 2nd Objective, 624 eligible children diagnosed with H. pylori PDU were studied on antimicrobial susceptibility (including non-resistant and resistant cases). + Sample selection: Children aged 2 years to 16 years, initially diagnosed with suspected PDU, admitted to the National Pediatric Hospital, were explained about the research purpose and contents. Once families had agreed to participate, doctors asked their history, performed PDU physical examination, endoscopy, biopsy, urease test, dyeing H. pylori shed for histopathology, and culture for H. pylori bacteria, then antimicrobial susceptibility test to determine 14 drug resistance. Cases diagnosed with H. pylori(+) PDU resisting to at least 1 in 8 antibiotics: amoxicillin, clarithromycin, metronidazole, ciprofloxacin, tetracycline, azithromycin, levofloxacin and cefixime had been enrolled into the research. + Other samples To determine the possibility of cross-infection within family through studying genotype of isolated H. pylori strains, we selected 17 representative households participating in the study using a convenient sample. To determine association between the antibiotic resistance and the presence of genes CagA and VacA in H. pylori strains isolated from patients infected with antibiotic-resistant H. pylori, we selected for analysis 150 H. pylori strains by sampling conveniently, of which 50 resisted to amoxicillin, 50 to clarithromycin and 50 to metronidazole. 2.4.2.2. Sample size and sampling for the 3rd Objective + Sample size: based on total patients eligible for inclusion into the research during 2 years, from October 2011 until November 2013, including PDU patients caused by H. pylori resisted to at least 1 antibiotic drug, who agreed to participate and comply with treatment regimens prescribed. 195 patients were included in the list of treatment. They were divided into 2 groups: (i) Group 1 with 97 patients, receiving 4 medicines recommended by the Association of Pediatric Gastroenterology and Hepatobiliary of Europe and North America, Maastrich IV; (ii) Group 2 included 98 patients eligible for regimen with 3 drugs following their antimicrobial susceptibility, based on the routine treatment guidelines of National Pediatric Hospital. 15 + Sampling method: According to the convenient sampling, all subjects positive with H. pylori and resistant to antibiotics, whose families provided informed consent and committed to comply with treatment requirement were enrolled. CHAPTER 3: RESULTS 3.1. Several epidemiological and clinical characteristics of PDU caused by antibiotic-resistant H. pylori 3.1.1. Several epidemiological characteristics 3.1.1.1 Rate of pediatric PDU caused by antibiotic-resistant H. 5,8% kháng KS pylori (A-R) không kháng KS 94,2% Figure 3.1. Distribution of PDU cases with antibiotic-resistant H. pylori at National Pediatric Hospital (n=624) From 624 pediatric H. pylori PDU patients examined and treated (October 2011 - November 2013), 588 found with antibiotic-resistant H. pylori (94.2%). 3.1.1.2. Distribution of antibiotic-resistant H. pylori PDU by age group Figure 3.2. Distribution of antibiotic-resistant H. pylori PDU by age group (n=588) This distribution showed that the youngest was 2 years old and the highest was 16 years old; average age was 7.29 ± 2.16; the highest proportion was in 6-9 years group (54.9%). 3.1.1.3. Distribution of antibiotic-resistant H. pylori PDU by sex Figure 3.3. Distribution of antibiotic-resistant H. pylori PDU by sex (n=588) 16 49.5% was male; this was equivalent to the proportion of females, 50.5%. 3.1.1.4. Gastric and duodenal history of patients’ family Figure 3.4. Gastric and duodenal history of patients’ family (n=588) Figure 3.5 showed that 72.3% pediatric patients came from families with PDU history, and 27.7% without this history. 3.1.1.5. History of antibiotic treatment Figure 3.5 - History of antibiotic treatment for other diseases (n=588) The result showed that proportion of patients who used antibiotic treatment for other diseases was 71.8%, and who had not used them was 28.2%. 3.1.1.6. H. pylori transmission in the family  General information about research subjects In this study, we had selected 17 households with H. pylori patients. 50 H. pylori strains were isolated from patients and family members, of those 17 were from pediatric patients, 33 from family members including fathers, mothers and brothers/sisters.  Genotypic analysis of H. pylori strains isolated from patients and family members: All 50 H. pylori strains were analyzed by RAPD technique. Results showed that 46.1% (6/13) mothers had genotypes similar to the ones of their children. In contrast, only 8.3% (1/12) fathers had genotypes similar to the ones of their children. 11.8% (2/17) 17 H. pylori strains of pediatric patients were similar to the ones of their brothers/sisters. 3.1.2. Several clinical and paraclinical characteristics 3.1.2.1. Clinical characteristics Figure 3.6 - Clinical characteristics of antibiotic-resistant H. pylori PDU Figure 3.6 showed that abdominal pain was the most common symptom, it accounted for 96.9% cases; anorexia 59.5% was also common. Symptoms of vomiting, belching, heartburn, bloating occupied respectively 46.9%; 29.3%; 18.7%; 19.2% and 6.1%. 3.1.2.2. Paraclinical characteristics  Gastroscopic images of injury Figure 3.7. Gastroscopic images of injury (n=588) Endoscopic images showed that edema and congestion were the most common phenomena, accounting for 94.2% cases; lumpy and granular lesions occupied 69.9%. PDU presented only in 5.8% patients. Figure 3.8. Locating gastroduodenal lesions by endoscopy (n = 588) Endoscopic images showed that antral gastritis alone occupied 31.8% of 187 pediatric patients; whole gastric lesions presented in 57.1% of them. Table 3.1. Histopathological characteristics of antibioticresistant H. pilori PDU 18 Histopathological Number Proportion characteristics (n=588) % Location of lesion Body of stomach 7 1,2 Antrum of stomach 36 6,1 Whole stomach 545 92,7 Histopathological lesions were mainly whole stomach inflammation (92.7%), moderate and severe gastritis occupied 78.6%. 3.2. Levels of antibiotic resistance, and factors related to antibiotic resistance in H. pylori PDU children 3.2.1. Antibiotic resistance of H. pylori strains Out of 624 H. pylori strains isolated, 5.8% were sensitive, 59.8% were resisted to 2 or more antibiotics, and 215 strains (34.4%) resisted to 1 antibiotic (Figure 3.9) Figure 3.9. Level of antibiotic resistance, H. pylori strains (n = 624) 3.2.2. General resistance of H. pylori to antibiotics Table 3.2. Resistance of H. pylori to each antibiotic (n=624) Sensitive Medium Resistant Antibiotic N % n % n % Clarithromycin 238 38.1 33 5.3 353 56.6 Azithromycin 265 42.5 11 1.8 348 55.8 Metronidazole 423 67.8 19 3 182 29.2 Amoxicillin 479 76.8 31 5 114 18.3 Cefixime 548 87.8 4 0.6 72 11.5 Ciprofloxacin 597 95.7 16 2.6 11 1.8 19 Tetracycline 621 99.5 0 0 3 0.5 Levofloxacin 603 99.3 2 0.3 2 0.3 Resistance to clarithromycin was the most serious with the highest proportion of 56.6%. Resistance to azithromycin, metronidazole, amoxicillin, and ciprofloxacin cefixime were respectively 55.8%, 29.2%, 18.3%, 11.5% and 1.8 %. 3.2.3. Multidrug resistance of H. pylori isolated Table 3.3. Resistance to two or more antibiotics (MDR) Antibiotic No. resistant % strains (n=624) CLA + AZ 191 30.6 MTZ + AZ 112 17.9 CLA + MTZ 61 9.8 AMX + CLA 57 9.1 AMX + MTZ 25 4.0 MTZ + CLA + AZ 41 6.6 AMX + CLA + AZ 16 2.6 CLA + AZ + CIP 1 0.2 MTZ + CEF + CLA + 4 0.6 AZ Resistance to two antibiotics - azithromycin and clarithromycinis - was the highest (30.6%). 9.1% H. pylori strains resisted to both amoxicillin and clarithromycin. Resistance to 3 antibiotics azithromycin+ clarithromycin + metronidazole - was 6.6%. Resistance to 4 antibiotics - azithromycin + clarithromycin + metronidazole + cefotaxime - was 0.6%. 3.2.4. Distribution of antibiotic resistance Table 3.4. Distribution of antibiotic resistance by sex (n=624) 20 Sex Male (n=305) n % 187 61.3 Female (n=319) n % 166 52.0 P Antibiotic Clarithromycin 0.019a (n=353) Amoxicillin 52 17.0 62 19.4 0.441a ( n=114) Metronidazole 90 29.5 92 28.8 0.854a (n=182) Ciprofloxacin 5 1.6 6 1.9 0.531a (n=11) Azithromycin 168 55.1 180 56.4 0.735a (n=348) Tetracycline (n=3) 2 0.7 1 0.3 0.616b Levofloxacin (n=2) 1 0.3 1 0.3 1.00b Cefixim (n=72) 40 13.1 32 10.0 0.228a a. Chi-squared test b. Fisher’ Exact test Resistance to clarithromycin was higher in men (61.3%) than in female (52%), the difference was statistically significant with P <0.05. For other antibiotics, there was no sex difference, P > 0.05. 3.2.5. Factors related to resistance to one antibiotic Two 2 groups of children with H. pylori PDU – one was sensitive to antibiotics (36 patients) and the other was resisted to some antibiotic (215 patients) - were analyzed to determine related factors.