Analysis of Helicobacter pylori infections in Africa, bacterial virulence factors but lack of pathology
Final Report Abstract
A major focus of this collaborative research project within the DFG Africa Infectiology Initiative was a better understanding of the epidemiologic situation of H. pylori infections in Africa. Our earlier studies presented a remarkably mild pathology of Nigerian patients infected with H. pylori, but a high rate of antibiotic resistance. In this study, we also included South Africa. A network of eight hospitals in Nigeria, and one large hospital in Johannesburg, South Africa, was established. Coordination centers were located in Lagos, Nigeria, Fort Hare, South Africa and Munich, Germany. To study the epidemiological situation, this network was used to collect biopsies, patient-isolated strains, patient questionnaires (PQ) and the according diagnosis of the gastroenterologist (GD), which was then statistically correlated. A total of 492 completed PQs and 486 GDs were obtained from Nigeria (NG) and 629 PQs and 622 GDs from South Africa. A total of 88 (NG) and 132 (ZA) isolates (from 39/75 patients) were obtained for further analysis throughout the study. This provided a very detailed characterization of the isolates, which included quantification of antibiotic resistance, and placed it in context with the patient information. As an important result, the diagnosis of gastric erosion, gastric ulcer or cancer was significantly lower in South Africa, as compared to Nigeria, showing that H. pylori infections in South Africa tend to result in significantly lower frequencies of disease outcome as compared to Nigeria. This finding was supported by the study of virulence factor expression of Nigerian versus South African isolates. While all isolates of HpAfrica2 origin were negative for cagA, the vacA subtypes showed a mixed phenotype. Notably, in contrast to earlier reports we present data showing that vacA s1m1/m2 allelic forms are well compatible with the absence of the cagPAI and suggest that in ancient, cagPAI deficient strains both types, s1m1/m2 and s2m2 vacA genes were existent. The dupA gene analysis in African isolates, a marker of the duodenal ulcer promoting locus showed that of the 22 hpAfrica2 isolates analyzed, 16 had a full-length dupA gene, and in 6 isolates this region could not be amplified. Furthermore, 6 isolates were detected that showed evidence of both dupA forms, indicating the presence of more than one integrating conjugative element, or parts of it. Furthermore, CRISPR/Cas9-mediated knockout of CEACAM receptors (CEACAM1, CEACAM5 and CEACAM6 simultaneously) generated in KatoIII cells resulted in a complete loss of CagA translocation capacity by H. pylori, suggesting that β-integrin receptors play a minor role in the T4SS-mediated CagA translocation, but the H. pylori-CEACAM interaction is of major importance. Furthermore, we show that human or CEACAM-humanized, but not mouse neutrophils are amenable for CagA phosphorylation, activation and processing in neutrophils, whereas CagA translocation and tyrosine phosphorylation in DCs and macrophages was independent of the HopQ-CEACAM interaction. Antibiotic resistance rates were generally high for Nigerian and South African isolates with the highest rate for metronidazole (NG: 100 %; ZA: 83.3 %) and the lowest for tetracycline (NG: 13 %; ZA: 8.7 %) respectively. Our data suggest that low-level amoxicillin resistance in African isolates is generated by a cumulative effect of multiple sequence alterations in penicillin binding protein 1 and that the mechanism for high-level amoxicillin resistance in H. pylori is probably not encoded by a single gene, but might be the result of multiple allelic alterations. Finally, we trained the Nigerian and South African teams in a variety of laboratory skills. We hosted, two Ph.D. students from Nigeria and one from South Africa in the Munich laboratory for six months enabling them to acquire state-of-the-art methods which they passed on to colleagues in Africa. Infrastructure measures were especially necessary for the lab in Nigeria, which improved the technical standard of the labs. Overall, the DFG program considerably improved and expanded the cooperation between the African research institutes and the German partner Institut.
Publications
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Helicobacter pylori exploits human CEACAMs via HopQ for adherence and translocation of CagA. Nature Microbiol., Article Number: 16188
Königer V, Holsten L, Harrison U, Busch B, Loell E, Zhao Q, Bonsor DA, Roth A, Kengmo-Tchoupa A, Smith SI, Mueller S, Sundberg SJ, Zimmermann W, Fischer W, Hauck CR and Haas R
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Helicobacter pylori cytotoxin-associated gene A protein among adult dyspeptic patients in South-western Nigeria. African Journal of Microbiology Research 11 681-686
Seriki, AT, Smith SI, Adeleye AI, Fowora, MA, Lesi O, Onyekwere C, Ndububa D, Adekanle O, Otegbayo JA, Akere A
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Helicobacter pylori strains from a Nigerian cohort show divergent antibiotic resistance rates and a uniform pathogenicity profile. PLoS One 2;12(5):e0176454
Harrison U, Fowora MA, Seriki AT, Loell E, Mueller S, Ugo-Ijeh M, Onyekwere CA, Lesi OA, Otegbayo JA, Akere A, Ndububa DA, Adekanle O, Anomneze E, Abdulkareem FB, Adeleye IA, Crispin A, Fischer W, Smith SI, Haas R
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Clinical and socio-demographic risk factors for acquisition of Helicobacter pylori infection in Nigeria. Asian Pacific Journal of Cancer Prevention 19 (7) 1851-1857
Smith SI, Jolaiya T, Fowora M, Palamides P, Ngoka F, Bamidele M, Lesi O, Onyekwere C, Ugiagbe R, Agbo I, Ndububa D, Adekanle O, Adedeji A, Adeleye I, Harrison U
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Integrin but not CEACAM receptors are dispensable for Helicobacter pylori CagA translocation. PLoS Pathogens, 26;14(10):e1007359
Zhao Q, Busch B, Jiménez-Soto L-F, Ishikawa-Ankerhold H, Massberg S, Terradot L, Fischer W, Haas, R
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Detection of Helicobacter pylori and its virulence genes (cagA, dupA, and vacA) among patients with gastroduodenal diseases in Chris Hani Baragwanath Academic Hospital, South Africa. BMC Gastroenterol. 14;19(1):73
Idowu A, Mzukwa A, Harrison U, Palamides P, Haas R, Mbao M, Mamdoo R, Bolon J, Jolaiya T, Smith SI, Ally R, Clarke A, Njom H
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Excision and transfer of an integrating and conjugative element in a bacterial species with high recombination efficiency. Scientific Reports 9(1):8915
Weiss E, Spicher C, Haas R, Fischer W
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Prevalence of Helicobacter pylori infection among dyspeptic patients with and without type 2 diabetes mellitus in Nigeria. Minerva Gastroenterol Dietol. 65(1):36-41
Smith SI, Jolaiya T, Onyekwere C, Fowora M, Ugiagbe R, Agbo I, Cookey C, Lesi O, Ndububa D, Adekanle O, Palamides P, Adeleye I, Njom H, Idowu A, Clarke A, Pellicano R
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Helicobacter pylori patient isolates from South Africa and Nigeria differ in virulence factor pathogenicity profile and associated gastric disease outcome. Scientific Reports 10:11409
Palamides P, Jolaiya T, Idowu A, Loell E, Onyekwere C, Ugiagbe R, Agbo I, Lesi O, Ndububa D, Adekanle O, Carranza M, Ally R, Njom H, Adeleye IA, Harrison U, Clarke A, Fischer W, Smith SI and Haas R
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The HopQ-CEACAM interaction controls CagA translocation, phosphorylation and phagocytosis of Helicobacter pylori in neutrophils, mBio 11:e03256-19
Behrens I-K, Busch B, Ishikawa-Ankerhold H, Palamides P, Shively JE, Stanners C, Chan C, Leung N, Gray-Owen S, Haas, R
