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 This work has been completed at the National Institute of Hygiene And Epidemiology Instructors: Le Thanh Hai, Associate Professor, Ph.D 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: The National Library The Library, National Institute of Hygiene And Epidemiology 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 ( 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 0.05) 3.3.4 Side effects of medical treatments Common side effect of treatment regimens was stomach ache - 9.8% in drug regimen, and 8.1% in the antimicrobial susceptibility based regimen Side effects of the drug and antimicrobial susceptibility based regimen were 16.5% and 16.3% respectively CHAPTER 4: DISCUSSION 4.1 Epidemiological and clinical characteristics of drugresistant H pylori PDU among children at National Pediatric Hospital 4.1.1 Several epidemiological characteristics This research was done on 588 pediatric patients with drugresistant H pylori PDU whose average age was 7.29±2.16 Our research ages were lower than of some other authors; perhaps thanks to the full application of endoscopic anesthesia technique at National Pediatric Hospital, younger ages could be earlier diagnosed for PDU Analysis of prevalence by sex showed that boys occupied 291/588 (49.5%), equivalent to the one of girls 297/588 (50.5%) This finding was in accordance with other authors in Vietnam and in the world Analysis of patients with drug-resistant H pylori PDU showed that those who lived in Hanoi occupied a high proportion of 61.9%; other provinces occupied 38.1% Analyzing pediatric patients history we recognized that among those infected with drug-resistant species, 723% had family member(s) suffered from PDU and 27.% had no such history 30 This could explain why children diagnosed with H pylori PDU at early age, and they could be infected with drug-resistant H pylori strains from their family members Our findings agreed with identification by Tong Quang Hung Megraud and McMahon studied on relationship between H pylori antibiotic resistance and antibiotic consumption, as well as between macrolide antibiotic use and metronidazole resistance In our research 71.8% patients had previously used antibiotics, this explained very high rate of antibiotic resistance When studying transmission of H pylori within family, we had seen some relationship between bacterial strains isolated from mothers and their children (46.1% mothers had genotypes similar to the one their children had), this could be an evidence of mother-to-child transmission, especially at young ages Our research provided more evidence for proving H pylori transmission at molecular level within family, which was in accordance with Shiha and Megraud 4.1.2 Clinical symptoms Average duration of disease among H pylori PDU children in this research was 6.0 month, longer than findings of some other authors; our research worked on antibiotic-resistant patients with prolonged disease duration, thus bacteria had better chance to get exposed to antibiotics, and therefore risks of drug resistance could increase Analysis of clinical findings showed that clinical symptoms of H pylori PDU in children were not specific, and easy to get confused with symptoms of other diseases Our findings showed that stomach ache was the most common symptom, occupying 31 96.9% Our findings were similar to the one of authors in and out of the country Stomach ache was changeable, unstable, it might appear and disappear with time; the pain could be localized or generalized, around navel or epigastric regions; findings also showed that pain around navel was the most common, occupying 75.9%; pain in the epigastric region occupied 26.9% in our research Our findings were appropriate to Tong Quang Hung’s ones Anorexia was often met, in our research it occupied 59.5%, appropriate to the research by Le Thi Ngoc Dung Analyzing endoscopic images showed that antral gastritis with nodules and lumpy granulars were specific only to H pylori PDU Results of our research on patients infected with drugresistant species revealed that edema and congestion were the most commonly seen, occupying 94,2%; nodules and lumpy granulars were also often met, occupying 69.9% Our findings were in accordance with results of Nguyen Gia Khanh Role of H pylori in PDU was confirmed in many researches; Malfertheiner found PDU in H pylori infected group was 15 times higher than in non-infected group Successful H pylori clearance treatment reduced ulcers In our research this was 5.8%, appropriate to findings by Arenz and Koletzko Discussing on locating lesions in endoscopic images for H pylori PDU, authors believed that H.pylori resided mainly – with the highest density - in antrum than in other regions In our research, lower gastritis rate might due to younger ages; our findings were similar to the ones of Tong Quang Hung 32 4.2 Antibiotic resistance and some related factors 4.2.1 Antibiotic resistance of H pylori strains When studying antibiotic resistance of H pylori strains, our rate of resistance to antibiotic was 34,4% Our finding was similar to the one of Duck Rat of resistance to ≥ antibiotics was rather high in our research - 59.8%, much higher than in research of Duck and Seo 4.2.2 General antibiotic resistance of H pylori Based on obtained results, we had assessed antibiotic resistance of isolated H pylori strains from patients, concretely:  Amoxicillin: According to researches of some authors worldwide, amoxicillin resistance rate varied from 0.6-59% Our research found amoxicillin primary resistance rate 18.3%, higher than finding of Nguyen Thi Viet Ha and Boyanova  Clarithromycin: In our research, clarithromycin resistance rate occupied 56.6%, higher than finding by Nguyen Viet Ha and Agudo  Metronidazole: Metronidazole resistance rate in our research was 29.2%, lower than of Nguyen Thi Viet Ha, however it was similar to findings by Manfredi and Seo  Ciprofloxacin: With the primary resistance rate of 1.8%, our finding was equivalent to findings by Agudo and Lopes  Azithromycin: This research found azithromycin resistance rate 55.8%, lower than finding by Goudong Liu, and higher than finding by Seo 33  Tetracycline: Tetracyclin resistance rate in our research was 0.5%; our finding was similar to findings by Street and Ve’csei  Cefixime: In our research cefixim resistance rate was rather high at 11.5%, higher than finding by Samra 4.2.3 Multidrug Resistance In our research rate of resistance to both clarithromycin and azithromycin occupied the highest proportion of 30.6%; this was lower than the one from research by Liu and Nguyen Thi Viet Ha (2006), and was equivalent to finding of Street and Peretz 4.2.4 Antibiotic resistance by sex Studying antibiotic resistance by sex, we found that clarithromycin resistance rate among boys significantly higher than among girls; our finding was also similar to identification by Koletzo 4.2.5 Epidemiological factors related to single antibiotic resistance Relationship between age, sex and location of residence, and antibiotic history with a single antibiotic resistance was found in the research of Boyanova and Rafeey In our research, no relationship was found between single antibiotic resistance with age, sex, and location of residence 4.2.6 Epidemiological factors related to multidrug resistance Risk factors of multidrug resistance included sex, age, location of residence and race were found in certain researches In our research no relationship was found between multidrug resistance with age, sex, location, as well as disease status and antibiotic 34 history 4.2.7 Relationship between epidemiological characteristics and clarithromycin resistance Effectiveness of regimen containing clarithromycin was reduced 55% when there was resistance (Dore) Certain researches found factors related to clarithromycin resistance of H pylori, including macrolide antibiotic use, age, sex, race, disease status, cigarette smocking and residence In our research, boys had the risk of clarithromycin resistance at 1.46 time higher than girls, this was appropriate to identification of Koletzo Similarly, risk of clarithromycin resistance among PDU group was 3.06 time higher than among non PDU group; our research had different findings compared with the ones of Me’graud and Kist Among children in the community we studied, up to 71.8% had antibiotic use history, therefore exposure to antibiotics was the chance for developing resistance; the longer infection last, the more children exposed to antibiotics, leading to higher resistance 4.2.8 Relationship between epidemiological characteristics and metronidazole resistance Many researches pointed out that metronidazole resistance associated with location, sex and race (Meyer), and with place of birth of children and their mothers Our research had not found any relationship with metronidazole resistance regarding age, sex, location, disease status, as well as antibiotic history 4.2.9 Relationship between antibiotic resistance and cagA and vacA genes of H pylori strains resistant to antibiotics  Relationship between cagA and vacA genes and amoxicillin resistance: 35 Gene cagA (+) occupies 30.4% of the amoxicillin resistant group Genes vacAs1, vacAs2, vacAm1, and vacAm2 of 56 amoxicillin resistant strains were correspondingly 37.5%, 17.9%, 33.9% and 28.6%, no statistically significant difference was detected on cagA and vacA between groups of amoxicillin resistant and sensitive patients (P>0.05) Our findings were appropriate to identification of Gotaslou  Relationship between cagA and vacA genes and clarithromycin resistance: Among the group of clarithromycin resistance, 34.1% had cagA (+); this of the sensitive group was 33.9% Findings of our research were similar to the ones of Karabiber or Francesco in adults  Relationship between cagA and vacA genes and metronidazole resistance: In our research, in metronidazole resistant group, cagA (+) was 33.8%, in other, sensitive group its was 34.1% In the research of Taneike, metronidazole resistance rate in cagA (-) group was higher than in cagA(+) group, however our research had not found any difference between them 4.3 Description of H pylori clearance by certain treatment regimens for antibiotic-resistant H pylori PDU 4.3.1 Effectiveness of H pylori clearance by drug regimen Some researches suggested that drug regimen (amoxicillin + omeprazole + metronidazole + bismuth) was still effective where metronidazole and clarithromycin resistance was high In our research, effectiveness of H pylori clearance by drug regimen on pediatric patients who developed antibiotic resistance reached 36 77.3% Thus, with an effectiveness of nearly 80%, drug regimen was one choice for clinicians to treat pediatric patients with H pylori PDU when antibiotic resistance was high 4.3.2 Antimicrobial susceptibility based regimen H pylori clearance rate of common antimicrobial susceptibility based drug regimens in our research (Table 3.32) was 53.1% Our findings were lower than the ones of Faber and Yakoob Analyzing bacterial clearance rate of sensitive antibiotic pair regimen (Table 3.9), we had seen that treatment effectiveness of our common antimicrobial susceptibility based regimens was low due to very low effectiveness (32.1%) of amoxicillin + klacid + PPI regimen Of 28 pediatric patients who used OAC regimen, 15 were in age group of 3-6 years old, and this group’ H pylori clearance rate was 2/15 (13.3%), lower than of the 7-14 year age group (7/13=53.8%) with P=0.042; and of all these 28 children, 20 were infected with H pylori strains that were sensitive to clarithromycin but resistant to azithromycine, besides, among them 13/20 who had azithromycin resistant strains belonged to the group of 3-6 years old In the research of Tong Quang Hung on effectiveness of H pylori clearance by OAC regimen, for 3-6 years group, clearance effectiveness was low either (31.6%) Inadequate drug intake and/or poor adherence among younger children was a risk factor that reduced the regimen’s treatment effectiveness Tetracyclin + flagyl regimen had full H pylori clearance effectiveness with 7/7 pediatric patients, occupying 100%; in a research of Japan, this regimen effectiveness was 92.3% equivalent to our finding 37 Effectiveness of klacid+ flagyl regimen was 72.%, equivalent to the one of research by Casswall; however our regimen was to be used for weeks Effectiveness of H pylori clearance by tetracyclin + amoxicillin + omeprazole regimen was 55.6%, this could be the result of combining antibiotics whose bacterial clearance concentration was inadequate Effectiveness of amoxicillin + flagyl regimen on H pylori was 53.6%, lower than of Faber Research of Graham showed that metronidazole’s resistance in vivo and invivo was not similar; besides, metronidazole was bitter and difficult for small children to take, causing poor adherence of drug amount Effectiveness of our cefixime + flagyl regimen on H pylori was 8/16 (50%) Thus, bacterial clearance effectiveness was lower than in the research of Pellicano 4.3.3 Factors affecting effectiveness of H pylori clearance Our research antimicrobial susceptibility based regimen’s bacterial clearance rate in 7-15 years group was 3.2 time higher with 95%CI (1.39-7.33) compared with 3-6 years group, similar to the one of Tong Quang Hung Younger children faced more difficulty than elder ones in adhering to drug amount - this was appropriate to identification by Wermeille 4.3.4 Assessing post-treatment improvement of clinical symptoms Results showed that clinical symptoms’ clearance in the breathing test (-) group was 46.9%, this was 2.73 time higher than in the breathing test (+) group, with 95% CI = (1.44 – 5.19) Our findings were similar to the ones of Tong Quang Hung, and 38 lower than the ones in research of Das We recorded a reduction of stomach ache at 2.58 time with 95% CI = (1.35-4.92) among the group with H pylori cleared than among the group still carrying H pylori Our research results were also similar to the ones of Montes and Casswall 4.3.5 Treatment side effects Side effects of antibiotics and secrete preventing drugs recorded in our research were stomach ache, nausea, headache, and dizziness In fact, it was very difficult to recognize stomach ache and vomiting as unwanted effects of drugs, or symptoms of the disease being studied Side effects of drug, and antimicrobial susceptibility based regimens, occupied 16.5 and 16.3% Our findings were in accordance with researches of Tong Quang Hung and Nguyen Thi Viet Ha CONCLUSIONS Studying epidemiological and clinical characteristics on 588 pediatric patients with H pylori antibiotic-resistant PDU, related factors on 624 pediatric patients with PDU, and treatment outcomes on 195 pediatric patients, we came to the following conclusions: Some epidemiological and clinical characteristics of H pylori antibiotic-resistant PDU - PDU caused by antibiotic-resistant H pylori was present mainly in school age children (average age 7.29±2.16) Most pediatric patients had family members with peptic pathological conditions (72.3%) and a history of antibiotic use during the last months (71.8%) Mother to child transmission was rather high (46.1% children had genotype similar to their mothers) 39 - Clinical symptoms of drug-resistant H pylori PDU were not specific; stomach ache was the most frequent (96.9%), followed by anorexia 59.5%, vomiting 46.9%, belching 29.3%, and heartburn 18.% - Lesions on endoscopic images: edema and mucosal congestion were the most frequent lesions (94.2%), followed by 69.9% of nodule and lumpy granular lesions Whole stomach lesions occupied the highest proportion of 57.1%, followed by antral gastritis 31.8% and peptic ulcers 5.8% Identifying levels and certain factors related to antibiotic resistance on pediatric patients with H pylori PDU - Multidrug resistance occupied a significant proportion (59.8%); single antibiotic resistance was 34,4% - Currently used antibiotics (clarithromycin, azithromycin, metronidazole, and amoxicillin) had very high rate of resistance (correspondingly 56.6%, 55.8%, 29.2%, and 18.3%) Coresistance to antibiotics was mostly happened with azithromycin and clarithromycin (30,6%), the lowest rate belonged to clarithromycin and metronidazole (9.8%) Triple resistance to azithromycin + clarithromycin + metronidazole was low - 6,6% Quadruplet resistance to azithromycin + clarithromycin + metronidazole + cefixime occupied a very low proportion of 0.6% - No relationship was found between antibiotic resistance with factors such as age, sex, and location of residence - Factors related to clarithromycin resistance included boys (OR=1.42); history of antibiotic use (OR=2.45) and history of peptic ulcer (OR= 3.06) 40 - No relationship was found between bacterial toxicity (cagA and vacA genes) and resistance to clarithromycin, metronidazole and amoxicillin H pylori clearance by certain treatment regimens for H pylori antibiotic-resistant PDU: - H pylori clearance rate of drug regimen was rather high: 77.3% - Bacterial clearance rate of antimicrobial susceptibility based drug regimen was lower: 53.1%; however its effectiveness depended also on combinations of sensitive antibiotics: clearing 100% by tetracyclin + flagyl regimen; and 32.1% by amoxicillin + klacid Clearance of clinical symptoms in the breathing test (-) group was 2.73 time higher than of the breathing test (+) group, and 3.18 time in the breathing test (-) group by antimicrobial susceptibility based regimen Side effects of drug regimen occupied 16.5%, equivalent to antimicrobial susceptibility based regimen RECOMMENDATIONS Provided with high levels of H pylori antibiotic resistance, it is important to pay special attention to closely indicate treatment regimen for PDU, especially for children under years old Four drug regimen is highly effective, and it is advisably to apply to the first treatment of children with H pylori PDU in order to reduce risks of multidrug resistance by H pylori It is not necessary to chose different treatment regimens for pediatric patients infected with antibiotic-resistant H pylori that have cagA and vacA genes 41 It is necessary to assess bacterial toxicity on pediatric patients with antibiotic-resistant H pylori PDU in order to orientate their follow-up and treatment THE THESIS RELATES TO PUBLISHED TOPICS Nguyen Thi Ut, Pham Dieu Quynh, Le Thanh Hai, Hoang Thi Thu Ha (2015), “Studying CagA and vacA genes on antibiotic resistant Helicobacter pylori strains isolated from pediatric patients, Vietnam”, Journal of Medical Research, Hanoi Medical University, Vol 96, No pp 41-50 Nguyen Thi Ut, Le Thanh Hai, Hoang Thi Thu Ha (2015), “Effectiveness of Helicobacter pylori clearance of antimicrobial susceptibility based drug regimen compared with drug regimen for children”, Journal of Preventive Medicine, Vol XXV, No (186), pp 409-419