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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="research-article" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Journal of microbiology, epidemiology and immunobiology</journal-id><journal-title-group><journal-title xml:lang="en">Journal of microbiology, epidemiology and immunobiology</journal-title><trans-title-group xml:lang="ru"><trans-title>Журнал микробиологии, эпидемиологии и иммунобиологии</trans-title></trans-title-group></journal-title-group><issn publication-format="print">0372-9311</issn><issn publication-format="electronic">2686-7613</issn><publisher><publisher-name xml:lang="en">Central Research Institute for Epidemiology</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">1359</article-id><article-id pub-id-type="doi">10.36233/0372-9311-298</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>ORIGINAL RESEARCHES</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>ОРИГИНАЛЬНЫЕ ИССЛЕДОВАНИЯ</subject></subj-group><subj-group subj-group-type="article-type"><subject>Research Article</subject></subj-group></article-categories><title-group><article-title xml:lang="en">Virulence determinants and genotypes of <italic>Helicobacter pylori</italic> clinical isolates</article-title><trans-title-group xml:lang="ru"><trans-title>Детерминанты вирулентности и генотипы клинических изолятов <italic>Helicobacter pylori</italic></trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-9340-4132</contrib-id><name-alternatives><name xml:lang="en"><surname>Svarval</surname><given-names>Alena V.</given-names></name><name xml:lang="ru"><surname>Сварваль</surname><given-names>Алена Владимировна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Cand. Sci. (Med.), Head, Department for identification of pathogens</p></bio><bio xml:lang="ru"><p>к.м.н., зав. лаб. идентификации патогенов</p></bio><email>dariastarkova13@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0003-3199-8689</contrib-id><name-alternatives><name xml:lang="en"><surname>Starkova</surname><given-names>Daria A.</given-names></name><name xml:lang="ru"><surname>Старкова</surname><given-names>Дарья Андреевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Cand. Sci. (Biol.), researcher, Department for identification of pathogens, Department of molecular epidemiology and evolutionary genetics</p></bio><bio xml:lang="ru"><p>к.б.н., с.н.с. лаб. идентификации патогенов, н.с. лаб. молекулярной эпидемиологии и эволюционной генетики</p></bio><email>dariastarkova13@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-7661-3725</contrib-id><name-alternatives><name xml:lang="en"><surname>Ferman</surname><given-names>Raisa S.</given-names></name><name xml:lang="ru"><surname>Ферман</surname><given-names>Раиса Семеновна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>researcher, Department for identification of pathogens</p></bio><bio xml:lang="ru"><p>м.н.с. лаб. идентификации патогенов</p></bio><email>dariastarkova13@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">St. Petersburg Pasteur Institute</institution></aff><aff><institution xml:lang="ru">Санкт-Петербургский научно-исследовательский институт эпидемиологии и микробиологии им. Пастера</institution></aff></aff-alternatives><pub-date date-type="pub" iso-8601-date="2022-12-15" publication-format="electronic"><day>15</day><month>12</month><year>2022</year></pub-date><volume>99</volume><issue>6</issue><issue-title xml:lang="en"/><issue-title xml:lang="ru"/><fpage>692</fpage><lpage>700</lpage><history><date date-type="received" iso-8601-date="2023-01-10"><day>10</day><month>01</month><year>2023</year></date><date date-type="accepted" iso-8601-date="2023-01-10"><day>10</day><month>01</month><year>2023</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; 2022, Svarval A.V., Starkova D.A., Ferman R.S.</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; 2022, Сварваль А.В., Старкова Д.А., Ферман Р.С.</copyright-statement><copyright-year>2022</copyright-year><copyright-holder xml:lang="en">Svarval A.V., Starkova D.A., Ferman R.S.</copyright-holder><copyright-holder xml:lang="ru">Сварваль А.В., Старкова Д.А., Ферман Р.С.</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://creativecommons.org/licenses/by/4.0</ali:license_ref></license></permissions><self-uri xlink:href="https://microbiol.crie.ru/jour/article/view/1359">https://microbiol.crie.ru/jour/article/view/1359</self-uri><abstract xml:lang="en"><p><bold>Background.</bold> <italic>H. pylori </italic>is the principal causative agent of gastroduodenal disorders in humans. The development and severity of lesions in infected individuals depend on the virulence of <italic>H. pylori</italic> strains.</p> <p><bold>Aims: </bold>Detection of virulence determinants and comparative analysis of <italic>H. pylori</italic> genotypes in patients with chronic gastritis (CG) and duodenal ulcer (DU).</p> <p><bold>Materials and methods.</bold> The 53 <italic>H. pylori</italic> strains were isolated in St. Petersburg from patients with CG (<italic>n</italic> = 34) and DU (<italic>n</italic> = 19). The genetic determinants of virulence <italic>cagA</italic>, <italic>iceA</italic>, <italic>vacA </italic>and <italic>H. pylori</italic> genotypes in patients with CG and UC were determined using the standard PCR method.</p> <p><bold>Results. </bold>The <italic>cagA</italic> gene was found in 64.1% of <italic>H. pylori</italic> strains. The proportions of <italic>cagA</italic>+ isolates from patients with CG and DU was 55.8% (15/34) and 78.9% (15/19), respectively (<italic>p</italic> &gt; 0.05). The <italic>iceA1</italic> allele of <italic>H. pylori</italic> was detected in 47.4% of patients with DU, the <italic>iceA2</italic> — in 47.1% of patients with CG (<italic>p</italic> &gt; 0.05). The <italic>vacA</italic>s1 allele was significantly dominant in patients with DU — 94.7% versus 70.6% in CG (<italic>p</italic> &lt; 0.05). No significant difference in <italic>vacA</italic> m1 and m2 alleles was found in <italic>H. pylori</italic> from different groups of patients (<italic>p</italic> &gt; 0.05). All <italic>cagA</italic>+ strains were carriers of the <italic>vacA</italic> s1 allele. The vast majority of strains (10 out of 11) of the <italic>cagA</italic>–/<italic>vacA</italic>s2 genotype were isolated from patients with CG.</p> <p><bold>Conclusion. </bold>The significant association between <italic>vacA</italic>s1, <italic>vacA</italic>s2 allelic variants, as well as <italic>vacA </italic>s1/m2, <italic>vacA</italic> s2/m2 genotypes of the pathogen and severity of clinical manifestations of <italic>H. pylori</italic> infection has been established in our study. The <italic>vacA</italic>s1 and <italic>vacA</italic> s1/m2 genotypes of the pathogen are associated with duodenal ulcer.</p></abstract><trans-abstract xml:lang="ru"><p><bold>Введение. </bold><italic>Helicobacter pylori</italic> — основной возбудитель гастродуоденальных заболеваний человека, развитие и степень тяжесть которых зависят от вирулентности штаммов <italic>H. pylori.</italic></p> <p><bold>Цель</bold> — выявление детерминант вирулентности и сравнительный анализ генотипов <italic>H. pylori</italic> у пациентов с хроническим гастритом (ХГ) и язвенной болезнью двенадцатиперстной кишки (ЯБДК).</p> <p><bold>Материалы и методы.</bold> Изучены 53 штамма <italic>H. pylori</italic>, выделенные в Санкт-Петербурге от пациентов с <italic>H. pylori</italic>-ассоциированными заболеваниями: 34 — с ХГ, 19 — с ЯБДК. Стандартным методом ПЦР определены генетические детерминанты вирулентности <italic>cagA, iceA, vacA</italic> и генотипы <italic>H. pylori </italic>у пациентов с ХГ и ЯБДК.</p> <p><bold>Результаты.</bold> Ген <italic>cagA </italic>обнаружен у 64,1% штаммов<italic> H. pylori</italic>. У пациентов с ХГ и ЯБДК доля <italic>cagA</italic>+ штаммов <italic>H. pylori</italic> составляла 55,8 и 78,9 соответственно (<italic>р</italic> &gt; 0,05). Аллельный вариант <italic>iceA1</italic> <italic>H. pylori</italic> выявлен у 47,4% пациентов с ЯБДК, <italic>iceA2 — </italic>у 47,1% пациентов с ХГ (<italic>р</italic> &gt; 0,05); аллель <italic>vacA</italic>s1 доминировал у штаммов, выделенных от больных ЯБДК (94,7% против 70,6% при ХГ; <italic>p</italic> &lt; 0,05). Существенной разницы в распределении аллельных вариантов m1 и m2 гена <italic>vacA H. pylori</italic> между группами пациентов не выявлено. Доля штаммов <italic>H. pylori</italic> генотипа s1/m2 у пациентов с ЯБДК (52,6%) значимо превышала таковую у пациентов с ХГ (20,6%); <italic>р</italic> = 0,02. Все <italic>cagA</italic>+ штаммы являлись носителями аллеля <italic>vacA</italic>s1. Подавляющее большинство штаммов (10 из 11) генотипа <italic>cagA</italic>-/<italic>vacA</italic>s2 выделены от больных ХГ.</p> <p><bold>Заключение.</bold> Установлена статистически значимая ассоциация аллельных вариантов <italic>vacA</italic>s1 и <italic>vacA</italic>s2, а также генотипов <italic>vacA </italic>s1/m2 и <italic>vacA </italic>s2/m2 возбудителя с тяжестью клинических проявлений инфекции <italic>H. pylori</italic>. Генотипы <italic>vacA</italic>s1 и <italic>vacA </italic>s1/m2 возбудителя ассоциированы с язвой двенадцатиперстной кишки.</p></trans-abstract><kwd-group xml:lang="en"><kwd>Helicobacter pylori</kwd><kwd>cagA</kwd><kwd>iceA</kwd><kwd>vacA</kwd><kwd>virulence determinant</kwd><kwd>genotyping</kwd><kwd>chronic gastritis</kwd><kwd>duodenal ulcer</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>Helicobacter pylori</kwd><kwd>cagA</kwd><kwd>iceA</kwd><kwd>vacA</kwd><kwd>генотипирование</kwd><kwd>гены вирулентности</kwd><kwd>хронический гастрит</kwd><kwd>язвенная болезнь двенадцатиперстной кишки</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><mixed-citation>de Brito B.B., da Silva F.A.F., Soares A.S., Pereira V.A., Santos M.L.C., Sampaio M.M., et al. Pathogenesis and clinical management of Helicobacter pylori gastric infection. World J. Gastroenterol. 2019; 25(37): 5578–89. https://doi.org/10.3748/wjg.v25.i37.5578</mixed-citation></ref><ref id="B2"><label>2.</label><mixed-citation>Nejati S., Karkhah A., Darvish H., Validi M., Ebrahimpour S., Nouri H.R. Influence of Helicobacter pylori virulence factors CagA and VacA on pathogenesis of gastrointestinal disorders. Microb. Pathog. 2018; 117: 43–8. https://doi.org/10.1016/j.micpath.2018.02.016</mixed-citation></ref><ref id="B3"><label>3.</label><mixed-citation>Covacci A., Telford J.L., Del Giudice G., Parsonnet J., Rappuoli R. Helicobacter pylori virulence and genetic geography. Science. 1999; 284(5418): 1328–33. https://doi.org/10.1126/science.284.5418.1328</mixed-citation></ref><ref id="B4"><label>4.</label><mixed-citation>Whitmire J.M., Merrell D.S. Helicobacter pylori genetic polymorphisms in gastric disease development. Adv. Exp. Med. Biol. 2019; 1149: 173–94. https://doi.org/10.1007/5584_2019_365</mixed-citation></ref><ref id="B5"><label>5.</label><mixed-citation>Foegeding N.J., Caston R.R., McClain M.S., Ohi M.D., Cover T.L. An overview of Helicobacter pylori VacA toxin biology. Toxins (Basel). 2016; 8(6): E173. https://doi.org/10.3390/toxins8060173</mixed-citation></ref><ref id="B6"><label>6.</label><mixed-citation>Atherton J.C., Cao P., Peek R.M.Jr., Tummuru M.K., Blaser M.J., Cover T.L. Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. Association of specific vacA types with cytotoxin production and peptic ulceration. J. Biol. Chem. 1995; 270(30): 17771–7. https://doi.org/10.1074/jbc.270.30.17771</mixed-citation></ref><ref id="B7"><label>7.</label><mixed-citation>Van Doorn L.J., Figueiredo C., Mégraud F., Pena S., Midolo P., Queiroz D.M., et al. Geographic distribution of vacA allelic types of Helicobacter pylori. Gastroenterol. 1999; 116(4): 823–30. https://doi.org/10.1016/s0016-5085(99)70065-x</mixed-citation></ref><ref id="B8"><label>8.</label><mixed-citation>Tumurru M.K., Cover T.L., Blaser M.J. Cloning and expression of a high-molecular mass major antigen of Helicobacter pylori: evidence of linkage to cytotoxin production. Infect. Immun. 1993; 61(5): 1799–809. https://doi.org/10.1128/iai.61.5.1799-1809.1993</mixed-citation></ref><ref id="B9"><label>9.</label><mixed-citation>Yamaoka Y., Kodama T., Gutierrez O., Kim J.G., Kashima K., Graham D.Y. Relationship between Helicobacter pylori iceA, cagA, and vacA status and clinical outcome: studies in four different countries. J. Clin. Microbiol. 1999; 37(7): 2274–9. https://doi.org/10.1128/jcm.37.7.2274-2279.1999</mixed-citation></ref><ref id="B10"><label>10.</label><mixed-citation>van Doorn L.J., Figueiredo C., Sanna R., Plaisier A., Schneeberger P., de Boer W., et al. Clinical relevance of the cagA, vacA, and iceA status of Helicobacter pylori. Gastroenterol. 1998; 115(1): 58–66. https://doi.org/10.1016/s0016-5085(98)70365-8</mixed-citation></ref><ref id="B11"><label>11.</label><mixed-citation>Miehlke S., Kirsch C., Agha-Amiri K., Günther T., Lehn N., Malfertheiner P., et al. The Helicobacter pylori vacA s1, m1 genotype and cagA is associated with gastric carcinoma in Germany. Int. J. Cancer. 2000; 87(3): 322–7.</mixed-citation></ref><ref id="B12"><label>12.</label><mixed-citation>Podzorski R.P., Podzorski D.S., Wuerth A., Tolia V. Analysis of the vacA, cagA, cagE, iceA, and babA2 genes in Helicobacter pylori from sixty-one pediatric patients from the Midwestern United States. Diagn. Microbiol. Infect. Dis. 2003; 46(2): 83–8. https://doi.org/10.1016/s0732-8893(03)00034-8</mixed-citation></ref><ref id="B13"><label>13.</label><mixed-citation>Perng C.L., Lin H.J., Sun I.C., Tseng G.Y. Helicobacter pylori cagA, iceA and vacA status in Taiwanese patients with peptic ulcer and gastritis. J. Gastroenterol. Hepatol. 2003; 18(11): 1244–9. https://doi.org/10.1046/j.1440-1746.2003.03214.x</mixed-citation></ref><ref id="B14"><label>14.</label><mixed-citation>Uchida T., Miftahussurur M., Pittayanon R., Vilaichone R.K., Wisedopas N., Ratanachu-Ek T., et al. Helicobacter pylori infection in thailand: a nationwide study of the CagA phenotype. PLoS One. 2015; 10(9): e0136775. https://doi.org/10.1371/journal.pone.0136775</mixed-citation></ref><ref id="B15"><label>15.</label><citation-alternatives><mixed-citation xml:lang="en">Govorun V.M., Momynaliev K.T., Smirnova O.V., Chelysheva V.V., Kudryavtseva L.V., Sergienko V.I., et al. The modern approaches to molecular diagnostics and identification of Helicobacter pylori clinical isolates in Russia. Rossiyskiy zhurnal gastroenterologii, gepatologii, koloproktologii. 2002; 12(3): 57–65. (in Russian)</mixed-citation><mixed-citation xml:lang="ru">Говорун В.М., Момыналиев К.Т., Смирнова О.В., Челышева В.В., Кудрявцева Л.В., Сергиенко В.И. и др. Современные подходы к молекулярной диагностике и типированию клинических изолятов Helicobacter pylori в России. Российский журнал гастроэнтерологии, гепатологии, колопроктологии. 2002; 12(3): 57–65.</mixed-citation></citation-alternatives></ref><ref id="B16"><label>16.</label><citation-alternatives><mixed-citation xml:lang="en">Spivak E.M., Levit R.M., Kuz'mina G.V., Demenchuk M.Yu. Influence of genetic characteristics of Helicobacter pylori on pathomorphology of gastric mucosa in young persons with chronic gastritis. Bakteriologiya. 2017; 2(4): 25–9. https://doi.org/10.20953/2500-1027-2017-4-25-29 (in Russian)</mixed-citation><mixed-citation xml:lang="ru">Спивак Е.М., Левит Р.М., Кузьмина Г.В., Деменчук М.Ю. Влияние генетической характеристики Helicobacter pylori на воспалительный процесс в слизистой оболочке верхних отделов пищеварительного тракта детей с хроническим гастритом. Бактериология. 2017; 2(4): 25–9. https://doi.org/10.20953/2500-1027-2017-4-25-29</mixed-citation></citation-alternatives></ref><ref id="B17"><label>17.</label><citation-alternatives><mixed-citation xml:lang="en">Bereznyak E.A., Sorokin V.M., Karpova I.O., Stupina N.A., Terent'ev A.N. Genotype peculiarities of regional Helicobacter pylori strains from the Rostov district. Epidemiologiya i vaktsinoprofilaktika. 2013; (4): 30–3. (in Russian)</mixed-citation><mixed-citation xml:lang="ru">Березняк Е.А., Сорокин В.М., Карпова И.О., Ступина Н.А., Терентьев А.Н. Особенности генотипов штаммов Helicobacter pylori, циркулирующих в Ростовской области. Эпидемиология и вакцинопрофилактика. 2013; (4): 30–3.</mixed-citation></citation-alternatives></ref><ref id="B18"><label>18.</label><citation-alternatives><mixed-citation xml:lang="en">Sorokin V.M., Pisanov R.V., Vodop'yanov A.S., Golubkina E.V., Bereznyak E.A. Comparative analysis of genotypes of Helicobacter pylori strains in the Rostov and Astrakhan regions. Meditsinskiy vestnik Yuga Rossii. 2018; 9(4):81–6. https://doi.org/10.21886/2219-8075-2018-9-4-81-86 (in Russian)</mixed-citation><mixed-citation xml:lang="ru">Сорокин В.М., Писанов Р.В., Водопьянов А.С., Голубкина Е.В., Березняк Е.А. Сравнительный анализ генотипов штаммов Helicobacter pylori в Ростовской и Астраханской области. Медицинский вестник Юга России. 2018; 9(4):81–6. https://doi.org/10.21886/2219-8075-2018-9-4-81-86</mixed-citation></citation-alternatives></ref><ref id="B19"><label>19.</label><mixed-citation>Abu-Taleb A.M.F., Abdelattef R.S., Abdel-Hady A.A., Omran F.H., El-Korashi L.A., Abdel-Aziz El-Hady H., et al. Prevalence of Helicobacter pylori cagA and iceA genes and their association with gastrointestinal diseases. Int. J. Microbiol. 2018; 2018: 4809093. https://doi.org/10.1155/2018/4809093</mixed-citation></ref><ref id="B20"><label>20.</label><mixed-citation>Wei G.C., Chen J., Liu A.Y., Zhang M., Liu X.J., Liu D., et al. Prevalence of Helicobacter pylori vacA, cagA and iceA genotypes and correlation with clinical outcome. Exp. Ther. Med. 2012; 4(6): 1039–44. https://doi.org/10.3892/etm.2012</mixed-citation></ref><ref id="B21"><label>21.</label><mixed-citation>Boyanova L., Yordanov D., Gergova G., Markovska R., Mitov I. Association of iceA and babA genotypes in Helicobacter pylori strains with patient and strain characteristics. Antonie Van Leeuwenhoek. 2010; 98(3): 343–50. https://doi.org/10.1007/s10482-010-9448-y</mixed-citation></ref><ref id="B22"><label>22.</label><mixed-citation>Almeida N., Donato M.M., Romãozinho J.M., Luxo C., Cardoso O., Cipriano M.A., et al. Correlation of Helicobacter pylori genotypes with gastric histopathology in the central region of a South-European country. Dig. Dis. Sci. 2015; 60(1): 74–85. https://doi.org/10.1007/s10620-014-3319-8</mixed-citation></ref><ref id="B23"><label>23.</label><citation-alternatives><mixed-citation xml:lang="en">Akhtereeva A.R., Davidyuk Yu.N., Fayzullina R.A., Ivanovskaya K.A., Safin A.G., Safina D.D., et al. Prevalence of Helicobacter pylori genotypes in patients with gastroduodenal pathology in Kazan. Kazanskiy meditsinskiy zhurnal. 2017; (5): 723–8. https://doi.org/10.17750/KMJ2017-723 (in Russian)</mixed-citation><mixed-citation xml:lang="ru">Ахтереева А.Р., Давидюк Ю.Н., Файзуллина Р.А., Ивановская К.А., Сафин А.Г., Сафина Д.Д. и др. Распространённость генотипов Helicobacter pylori у пациентов с гастродуоденальной патологией в Казани. Казанский медицинский журнал. 2017; (5): 723–8. https://doi.org/10.17750/KMJ2017-723</mixed-citation></citation-alternatives></ref><ref id="B24"><label>24.</label><mixed-citation>Momynaliev K., Smirnova O., Kudryavtseva L., Govorun V. Helicobacter pylori genotypes in Russia. Eur. J. Clin. Microbiol. Infect. Dis. 2003; 22(9): 573–4. https://doi.org/10.1007/s10096-003-0987-2</mixed-citation></ref><ref id="B25"><label>25.</label><mixed-citation>Keikha M., Ali-Hassanzadeh M., Karbalaei M. Association of Helicobacter pylori vacA genotypes and peptic ulcer in Iranian population: a systematic review and meta-analysis. BMC Gastroenterol. 2020; 20(1): 266. https://doi.org/10.1186/s12876-020-01406-9</mixed-citation></ref><ref id="B26"><label>26.</label><mixed-citation>Ben Mansour K., Fendri C., Zribi M., Masmoudi A., Labbene M., Fillali A., et al. Prevalence of Helicobacter pylori vacA, cagA, iceA and oipA genotypes in Tunisian patients. Ann. Clin. Microbiol. Antimicrob. 2010; 9: 10. https://doi.org/10.1186/1476-0711-9-10</mixed-citation></ref><ref id="B27"><label>27.</label><mixed-citation>Ribeiro M.L., Godoy A.P., Benvengo Y.H., Mendonça S., Pedrazzoli J. Jr. Clinical relevance of the cagA, vacA and iceA genotypes of Helicobacter pylori in Brazilian clinical isolates. FEMS Immunol. Med. Microbiol. 2003; 36(3): 181–5. https://doi.org/10.1016/S0928-8244(03)00029-4</mixed-citation></ref><ref id="B28"><label>28.</label><mixed-citation>Lin H.J., Perng C.L., Lo W.C., Wu C.W., Tseng G.Y., Li A.F., et al. Helicobacter pylori cagA, iceA and vacA genotypes in patients with gastric cancer in Taiwan. World J. Gastroenterol. 2004; 10(17): 2493–7. https://doi.org/10.3748/wjg.v10.i17.2493</mixed-citation></ref><ref id="B29"><label>29.</label><mixed-citation>Erzin Y., Koksal V., Altun S., Dobrucali A., Aslan M., Erdamar S., et al. Prevalence of Helicobacter pylori vacA, cagA, cagE, iceA, babA2 genotypes and correlation with clinical outcome in Turkish patients with dyspepsia. Helicobacter. 2006; 11(6): 574–80. https://doi.org/10.1111/j.1523-5378.2006.00461.x</mixed-citation></ref><ref id="B30"><label>30.</label><mixed-citation>Marie M.A. Relationship between Helicobacter pylori virulence genes and clinical outcomes in Saudi patients. J. Korean Med. Sci. 2012; 27(2): 190–3. https://doi.org/10.3346/jkms.2012.27.2.190</mixed-citation></ref></ref-list></back></article>
