La démonstration du rôle de la CDT (« Cytolethal Distending Toxin ») de Helicobacterhepaticus dans le développement de l’hépatocarcinome murin fait de cette toxine un candidatpertinent dans l'activation de processus pro-cancéreux. Comme la toxine CagA de Helicobacterpylori, la sous-unité active CdtB de la CDT pourrait être une oncoprotéine. Nous avons étudié lerôle de la CdtB des Hélicobacters dans l’inflammation et la carcinogenèse digestive via unestratégie lentivirale d’expression constitutive ou conditionnelle de la CdtB ou de son mutant pourl’activité DNase. Nous avons réalisé une étude du transcriptome et montré que la CdtB deH. hepaticus induisait une réponse inflammatoire en surexprimant des cytokines, chimiokines,peptides antimicrobiens et en activant la voie du NF-κB des cellules épithéliales. La CdtB réguleégalement l’expression et la localisation nucléaire du facteur de transcription et oncogène MafB.Ces résultats ont été confirmés pour la CdtB de Helicobacter pullorum. Des expériencesd'infection des cellules avec des souches sauvages et mutées pour la CDT (deH. hepaticus & H. pullorum) ont permis de valider les résultats obtenus et de les attribuer à laCdtB et notamment à son activité DNase. Nous avons aussi développé un nouveau modèle dexénogreffes de cellules épithéliales inductibles pour l’expression de la CdtB de H. hepaticus.Dans ce modèle, la CdtB, en plus de ses effets déjà connus, retarde la croissance tumorale,induit l’apoptose, la sénescence et la surexpression du marqueur nucléaire de prolifération,Ki-67, suggérant la survie cellulaire. L’ensemble de ces résultats fournit de nouveaux argumentsen faveur du potentiel oncogénique de la CDT. / The demonstration of the role of the Cytolethal Distending Toxin (CDT) of Helicobacter hepaticusin the development of hepatocarcinoma in mice, makes this toxin a relevant candidate in theactivation of precancerous processes. As in the case of the CagA toxin of Helicobacter pylori, theCdtB active subunit of CDT could be an oncoprotein. We studied the role of Helicobacter CdtB ininflammation and digestive carcinogenesis using a lentiviral strategy for constitutive or conditionalexpression of the CdtB subunit or its corresponding DNase mutant. We conducted a study of thetranscriptome and showed that CdtB induced an inflammatory response by overexpressingcytokines, chemokines, antimicrobial peptides and activating the NF-kB pathway in epithelialcells. The CdtB also regulated the expression and nuclear localization of the transcription factorand oncogene MafB. These results were confirmed for the CdtB of Helicobacter pullorum.Infection of cells with wild type strains and the corresponding CDT-mutant strains (of H. hepaticus& H. pullorum) were used to validate the results and to attribute the effects to the CdtB and, inparticular, to its DNase activity. We also developed a novel epithelial cell xenograft model toevaluate the inducible expression of H. hepaticus CdtB. In this model, the CdtB, in addition to itspreviously well-known effects, delayed tumor growth, induced apoptosis, senescence and theoverexpression of nuclear proliferation marker, Ki-67, suggesting cell survival. All of these resultsprovide new arguments in favor of the oncogenic potential of the CDT.

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Intracellular symbioses between bacteria and insects are numerous, and alter the ecology and evolution of host and symbiont alike. Long-term persistence results from either exploitation (e.g., reproductive manipulations) or mutually beneficial interactions (e.g., nutritional mutualisms). The endosymbiont Hamiltonella defensa, while not essential for growth or survival of healthy aphids, protects aphids from attack by parasitoid wasps. In this thesis, I have used a variety of sequenced-based techniques to illuminate the population and genome dynamics of H. defensa and to disentangle how these factors contribute to its ability to persist and protect its hosts.I characterized the phylogenetic relationships among H. defensa strains from aphids and a whitefly using a multilocus approach. Most loci evolve in a clonal manner, and one cluster of strains may have given rise to an obligate symbiosis. Some H. defensa strains were infected with the bacteriophage APSE, which encodes putative eukaryotic specific toxins and has been suggested to be involved in protecting aphids. I sequenced the toxin locus and the flanking regions from the APSE strains and found that although the phage genome backbone was highly conserved, strains contained non-orthologous toxin-cassettes. Sequenced cassettes contained one of three putative toxin families: Shiga toxin, cytolethal distending toxin, and YD-repeat toxins. A correlation was noted that of several genetically identical H. defensa strains, the one without phage APSE encoding the YD-repeat toxin failed to protect its aphid host. This APSE strain carrying the YD-repeat toxin has since been demonstrated to be essential for protection in several related H. defensastrains.To examine additional bacterial encoded loci that might facilitate the persistence in and protection of aphids by H. defensa, I sequenced the genome of one strain and obtained partial genomes of two additional strains. These genomes exhibit a streamlined metabolism, but are littered with mobile DNA and putative virulence factors. Horizontal gene transfer, recombination and rearrangements are common, and phage and plasmids have played an important role in resorting genes. Thus, although H. defensa benefits its host, its facultative lifestyle has resulted in a pattern of genome evolution associated with reproductive parasites rather than long-term mutualists.

Thermal instability in the toxin catalytic subunit may be a common property of toxins that exit the endoplasmic reticulum (ER) by exploiting the mechanism of ER-associated degradation (ERAD). The Haemophilus ducreyi cytolethal distending toxin (HdCDT) does not utilize ERAD to exit the ER, so we predicted the structural properties of its catalytic subunit (HdCdtB) would differ from other ER-translocating toxins. Here, we document the heat-stable properties of HdCdtB which distinguish it from other ER-translocating toxins. Cell-based assays further suggested that HdCdtB does not unfold before exiting the ER and that it may move directly from the ER lumen to the nucleoplasm. These observations suggest a novel mode of ER exit for HdCdtB.

La Cytolethal Distending Toxin (CDT) est un facteur de virulence produit par de nombreuses bactéries pathogènes Gram négatives. Sa production est associée à différentes pathologies, dont le développement de cancers. Un lien de causalité a été établi entre dommages à l’ADN, mutagénèse et cancérogenèse. Or, différentes études ont classé CDT dans la famille des génotoxines bactériennes. L’action génotoxique de CDT repose sur l’activité de sa sous-unité catalytique CdtB, connue pour induire des cassures double-brin (CDBs) de l’ADN génomique eucaryote. Cependant, des travaux de l’équipe ont montré qu’à des doses 1000 fois plus faibles que celles utilisées dans la littérature, CDT induit des dommages primaires (probablement de type cassure simple-brin), qui dégénèrent en CDB lors de la phase S. Afin de mieux documenter ce modèle, nous avons étudié ici les systèmes de réparation impliqués dans la réponse aux dommages à l’ADN induits par CDT. Nous avons ainsi confirmé l’importance des voies de réparations des CDBs (Homologous Recombinaison et Non-Homologous End-Joining). Nous avons également montré que le Nucleotide Excision Repair, impliqué dans la réparation des adduits à l’ADN, n’est pas impliqué dans la prise en charge des dommages induits par CDT. En revanche, nous avons démontré, pour la première fois, l’implication de systèmes de réparation de dommages plus précoces, comme le Single-Strand Break Repair et la voie de l’Anémie de Fanconi. Pour finir, afin de mieux caractériser ces dommages et leur induction, nous avons initié des travaux visant à étudier, in vitro, l’activité catalytique de CdtB. Dans ce but, différents mutants catalytiques ont été générés, purifiés, et leur activité nucléase a été testée. Une activité nucléase similaire entre les CdtB sauvages et mutantes a été obtenue lors d’un test in vitro (digestion d’un plasmide super-enroulé). Cependant, un test cellulaire (expression nucléaire en cellules eucaryotes de la sous-unité CdtB sauvage ou mutante) indique bien la perte de l’activité nucléase de la sous-unité mutante. Nos résultats montrent donc l’importance de tester les différentes sous-unités dans différents contextes. En conclusion, notre travail conforte les données selon lesquelles CDT induit des CSB, et non des CDB directes de l’ADN. De plus, notre travail a permis d’éclaircir les processus cellulaires activés dans la cellule hôte, suite aux dommages à l’ADN induits par CDT. / The Cytolethal Distending Toxin (CDT) is a virulence factor produced by many pathogenic gram-negative bacteria, its production being associated to various diseases, including tumorigenesis. A causal relationship has been established between DNA damage, mutagenesis and cancerogenesis. Different studies classified CDT among the bacterial genotoxins. The CDT-related pathogenicity relies on the catalytic subunit CdtB action, shown to induce double-strand breaks (DSB) on the host genomic DNA. Previously, our team showed that, at doses 1000 times lower than those used in the literature, CDT probably induces single-strand breaks that degenerate into DSB during S-phase. To document this model, we studied the repair systems involved in host-cell in response to CDT-induced DNA damage. Since various repair pathways allow cells to respond different type of DNA damage, we speculated that non-DSB repair mechanisms might contribute to the cellular resistance to CDT-mediated genotoxicity. First, we confirm that HR is involved in the management of CDT-induced lesions, but also Non Homologous End Joining, the second major DSB repair mechanism. Next we show that nucleotide excision repair, involved in adducts repair, is not important to take care of CDT-induced DNA damage, whereas base excision repair impairment sensitizes CDT-treated cells, suggesting that CDT induce single-strand breaks. Moreover, we demonstrate for the first time the involvement and the activation of the Fanconi Anemia repair pathway in response to CDT. Finally, to better characterize CDT-induced damage, we initiate experiments to study CdtB nuclease activity in vitro. For this, different CdtB mutants have been generated, purified and their nuclease activity tested. A similar nuclease activity has been obtained for the wt or mutant CdtB in an in vitro assay (digestion of a supercoiled plasmid). However, a cell assay (nuclear expression of CdtB in eukaryotic cells) confirms the loss of activity for the mutant subunit. Our results thus indicate the importance to test the CdtB subunit in different context. To conclude, our work reinforces a model where CDT induces single-strand damage and not direct DSB. This also underlines the importance of cell proliferation to generate DSB and sheds light on the activated host-cell systems, after CDT-induced DNA damage.

Aggregatibacter actinomycetemcomitans está associado à periodontite agressiva e produz CDT. Visando contribuir no entendimento do papel da CDT na regulação da resposta imune, foi determinada sua atividade sobre macrófagos e a resposta humoral contra a toxina. CDT inibiu a proliferação de células epiteliais OBA-9 e macrófagos Raw 264.7 e também a produção de NO por células Raw 264.7 e macrófagos peritoneais de camundongos C3H/HePas e C3H/HeJ, mas estimulou a produção de IL-12. Na imunidade humoral, 75% dos soros de indivíduos com PAgL e 81,8% dos PAgG foram reativos para A. actinomycetemcomitans. Não houve diferença na resposta contra CDTA e CDTB entre o soro de pacientes com diferentes condições periodontais. Todos os pacientes PAgG foram soropositivos para a CDTC, porém apenas 8,3% dos indivíduos com PAgL, nenhum dos PC e 25% dos saudáveis foram positivos. CDT tem atividade imunomodulatória e a resposta humoral difere entre indivíduos infectados pela bactéria. / Aggregatibacter actinomycetemcomitans is associated with aggressive periodontitis and produces CDT. Aiming to contribute in the understanding the CDT activity in the immune response regulation, its action on macrophages was determined and the response against the toxin analyzed. CDT inhibited the proliferation of OBA-9 epithelial cells and Raw 264.7 macrophages and also inhibited the NO production by Raw 264.7 cells and peritoneal macrophages of C3H/HePas and C3H/HeJ mice, however, stimulated the IL-12 production. In the humoral immunity, 75% of sera from LAgP subjects and 81.8% were reactive to A. actinomycetemcomitans. There was not difference in the response against CDTA and CDTB among sera of patients with different periodontal conditions. All GAgP subjects were sera-reactivity to CDTC, however only 8.3% LAgP subjects, none in CP and 25% of healthy subjects were positive. CDT has immunomodulatory activity and the humoral response differ among bacteria infected subjects.

Aggregatibacter actinomycetemcomitans está associado à periodontite agressiva, caracterizada pela intensa reabsorção do osso alveolar. Esta espécie produz a toxina distensora citoletal (AaCDT) que possui atividade de DNAse, e promove o bloqueio das células alvo na fase G2 ou G1/ G2. Por outro lado, CDT ativa a cascata apoptótica pela atividade de PIP3, regulando a proliferação e sobrevivência de linfócitos, pelo bloqueio de Akt. Em monócitos, AaCDT induz aumento da produção de citocinas pró-inflamatórias e inibe a produção de óxido nítrico e fagocitose. Células precursoras de osteoclastos têm origem hematopoiética e sofrem diferenciação em osteoclastos, mediada pelo RANKL, mas outros fatores co-estimulatórios estão envolvidos. A AaCDT induz a produção de RANKL por fibroblastos. Assim, formulamos a hipótese se CDT influenciaria a homeostase óssea por afetar a diferenciação de células precursoras de osteoclastos. O estudo visou determinar o efeito de AaCDT sobre a sobrevivência, diferenciação e atividade em RAW264.7 e BMC. Os dados sugerem que a CDT interfere na homeostase óssea, favorecendo a indução da diferenciação de células precursoras de osteoclastos e alterando o perfil de citocinas produzidas. / Aggregatibacter actinomycetemcomitans is associated with aggressive periodontitis, characterized by severe alveolar bone resorption. This species produces a distending toxin cytolethal (AaCDT) which has DNase activity, and promotes the blocking of target cells in G2 or G1 / G2 phase. On the other hand, CDT activates the apoptotic cascade by PIP3 activity, regulating lymphocyte proliferation and survival by blocking Akt. In monocytes, AaCDT enhances the production of proinflammatory cytokines and inhibits nitric oxide production and phagocytosis. Osteoclast precursor cells are of hematopoietic origin and must undergo differentiation into osteoclasts mediated by RANKL although other co-stimulatory factors are involved. AaCDT induces the production of RANKL by fibroblasts. Thus, CDT is hypothesized to influence bone homeostasis by affecting the differentiation of precursor cells into osteoclasts. This study aimed to determine the effect of AaCDT on survival, differentiation and activity of osteoclasts precursor cells. The data suggested that CDT interfere in bone homeostasis, favoring the differentiation of osteoclasts precursors cells and by altering their cytokines profile.

Orientador: Domingos da Silva Leite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-08T19:24:44Z (GMT). No. of bitstreams: 1 Peroto_MariaClaudia_M.pdf: 1526611 bytes, checksum: 77aa753a6b4be729c0ff45854cf7bdcf (MD5) Previous issue date: 2007 / Resumo: A toxina citoletal distensora, CDT, é uma citotoxina termolábil identificada em um grande número de enteropatógenos, entre eles Escherichia coli. Os genes de CDT são designados de cdtA, cdtB e cdtC e estão arranjados em um operon e, até o momento, já foram descritos cinco diferentes alelos: I, II, III, IV e V. Cepas de Escherichia coli podem ser classificadas em quatro grupos filogenéticos ECOR: A, B1, B2 e D, nos quais as cepas pertencentes aos grupos A e B1 são consideradas comensais e patógenos oportunistas e as cepas agrupadas como B2 e D, como cepas patogênicas. Os objetivos deste trabalho foram relacionar os alelos da CDT e alguns fatores de virulência associados aos grupos filogenéticos ECOR e estudar três conjuntos de cepas por eletroforese de campo pulsado (PFGE). Foram utilizadas 80 cepas de E. coli cdt-positivas isoladas de suínos, bovinos, ovinos, humanos, água e carne. Os alelos da CDT e os grupos filogenéticos foram identificados através da reação de polimerase em cadeia (PCR). Vinte e cinco cepas dos sorotipos O91:H21, O113:H21 e O116:H21 foram estudadas por PFGE para avaliação da diversidade genética. Os resultados demonstraram que o alelo V da CDT foi o mais freqüente, presente em 45% das cepas, mostrando forte associação com VT2 (97%); o alelo III foi observado em 36,2% das cepas, mostrando associação com VT1 em 79,0% das cepas. O alelo I da CDT foi detectado em 8,7% das cepas e o alelo IV em 5,0% das cepas. No estudo filogenético, 45 cepas (56,0%) foram agrupadas em B1, 15 cepas em B2 (18,7%), 13 cepa em D (16,2%) e sete cepas em A (8,7%). Nos ensaios de PFGE foi possível identificar, entre as cepas de um mesmo sorotipo, desde clones até cepas não relacionadas entre si. Os dados obtidos permitem concluir que no conjunto de cepas estudado o alelo CDT-V está associado ao grupo filogenético B1 enquanto o alelo CDT-III está associado aos grupos B2 e D / Abstract: Cytolethal distending toxin, CDT, is a termolabile cytotoxin found in a great number of enteropathogens, including Escherichia coli. The CDT genes are called cdtA, cdtB and cdtC and they are placed in an operon and five alleles (I, II, III, IV and V) were described until the moment. E. coli strains may be classified in four ECOR phylogenetic groups: A, B1, B2 and D; strains belonging to A and B1 groups are called commensal or opportunist pathogens and strains grouped as B2 and D, as pathogenic strains. The goals of this work were to relate the CDT alleles and some virulence factors associated to four ECOR phylogenetic groups and analyze three strain sets by pulsed field gel electrophoresis (PFGE). This study used 80 cdt-positive E. colistrains isolated from swines, bovines, ovines, humans, water and meat. CDT alleles and phylogenetic groups were identified using polymerase chain reaction (PCR). Twenty-five strains belonging to O91:H21, O113:H21 and O116:H21 serotypes were studied by PFGE for evaluation of genetic diversity. The results show that CDT-V was the most frequent allele, present in 45,0% of strains, and showing strong association with VT2 (97%); CDT-III was observed in 36,2% of strains, showing association with VT1 in 79,0% of strains. CDT-I was detected in 8,7% of strains and CDT-IV, in 5,0%. In the phylogenetic studies, 45 strains (56,0 %) was grouped in group B1, 15 strains (18,7%) was grouped in B2, D grouped 13 strains (16,2%) and the group A congregate 7 strains (8,7%). In PFGE studies it was possible to identify, in the same serotype, since clones until non-related strains. For the studied strains, data allows to conclude that CDT-V is associated to phylogenetic group B1 and CDT-III is associated to B2 and D groups / Mestrado / Microbiologia / Mestre em Genética e Biologia Molecular

Aggregatibacter actinomycetemcomitans está associado à periodontite agressiva, caracterizada pela intensa reabsorção do osso alveolar. Esta espécie produz a toxina distensora citoletal (AaCDT) que possui atividade de DNAse, e promove o bloqueio das células alvo na fase G2 ou G1/ G2. Por outro lado, CDT ativa a cascata apoptótica pela atividade de PIP3, regulando a proliferação e sobrevivência de linfócitos, pelo bloqueio de Akt. Em monócitos, AaCDT induz aumento da produção de citocinas pró-inflamatórias e inibe a produção de óxido nítrico e fagocitose. Células precursoras de osteoclastos têm origem hematopoiética e sofrem diferenciação em osteoclastos, mediada pelo RANKL, mas outros fatores co-estimulatórios estão envolvidos. A AaCDT induz a produção de RANKL por fibroblastos. Assim, formulamos a hipótese se CDT influenciaria a homeostase óssea por afetar a diferenciação de células precursoras de osteoclastos. O estudo visou determinar o efeito de AaCDT sobre a sobrevivência, diferenciação e atividade em RAW264.7 e BMC. Os dados sugerem que a CDT interfere na homeostase óssea, favorecendo a indução da diferenciação de células precursoras de osteoclastos e alterando o perfil de citocinas produzidas. / Aggregatibacter actinomycetemcomitans is associated with aggressive periodontitis, characterized by severe alveolar bone resorption. This species produces a distending toxin cytolethal (AaCDT) which has DNase activity, and promotes the blocking of target cells in G2 or G1 / G2 phase. On the other hand, CDT activates the apoptotic cascade by PIP3 activity, regulating lymphocyte proliferation and survival by blocking Akt. In monocytes, AaCDT enhances the production of proinflammatory cytokines and inhibits nitric oxide production and phagocytosis. Osteoclast precursor cells are of hematopoietic origin and must undergo differentiation into osteoclasts mediated by RANKL although other co-stimulatory factors are involved. AaCDT induces the production of RANKL by fibroblasts. Thus, CDT is hypothesized to influence bone homeostasis by affecting the differentiation of precursor cells into osteoclasts. This study aimed to determine the effect of AaCDT on survival, differentiation and activity of osteoclasts precursor cells. The data suggested that CDT interfere in bone homeostasis, favoring the differentiation of osteoclasts precursors cells and by altering their cytokines profile.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Campylobacter jejuni e Campylobacter coli sÃo importantes agentes etiolÃgicos de doenÃa diarrÃica na populaÃÃo mundial. A infecÃÃo por Campylobacter sp. à usualmente identificada por cultivo microbiolÃgico que leva aproximadamente 72 horas para identificaÃÃo do gÃnero. Nosso objetivo principal foi pesquisar a prevalÃncia de C. jejuni e C. coli em populaÃÃo infantil, com idade entre 2-36 meses, da Ãrea urbana de Fortaleza/CE, Brasil, em estudo do tipo epidemiolÃgico observacional caso-controle, utilizando, como ferramenta de detecÃÃo, a reaÃÃo em cadeia da polimerase (PCR). Outros objetivos consistiram em: investigar o impacto nutricional da infecÃÃo (casos) ou da colonizaÃÃo (controles) por Campylobacter sp.; determinar a presenÃa de trÃs genes de virulÃncia para a toxina citoletal distensora (CDT) de C. jejuni e avaliar a ocorrÃncia de inflamaÃÃo intestinal nas infecÃÃes causadas por Campylobacter sp. A populaÃÃo estudada consistiu de 83 casos e 83 controles, sendo os casos, crianÃas com histÃrico de diarrÃia nos 14 dias pregressos à seleÃÃo para o estudo. Foram avaliados parÃmetros sÃcio-econÃmicos atravÃs de questionÃrio epidemiolÃgico. Medidas antropomÃtricas foram coletadas para determinaÃÃo de escores-z no intuito de avaliar o perfil nutricional das crianÃas. A detecÃÃo de Campylobacter nas amostras congeladas foi realizada por ensaio imuno-enzimÃtico (ELISA) e PCR. Pela PCR tambÃm investigamos a presenÃa dos genes cdtA, cdtB e cdtC da CDT de C. jejuni. A avaliaÃÃo da inflamaÃÃo intestinal foi realizada pela pesquisa de lactoferrina fecal (LFF), atravÃs de ELISA semiquantitativa. Foi detectado, por PCR, C. jejuni em 9,6% dos casos (8/83) e 7,2% dos controles (6/83). C. coli foi detectado em 6,0% dos casos (5/83) e 1,2% dos controles (1/83). Os genes cdtA, cdtB e cdtC foram encontrados em 50% das amostras hipO+ (7/14). Houve diferenÃa significativa (p<0,05) dos escores WAZ e WHZ entre casos e controles portadores de C. jejuni, sendo que casos portadores apresentaram mÃdia inferior de WAZ e WHZ, quando comparados com os controles portadores. No grupo Casos, os portadores de C. jejuni apresentavam valor mÃdio de WHZ inferior ao valor mÃdio apresentado pelos casos nÃo-portadores. Mais de 80,0% das crianÃas estudadas apresentaram inflamaÃÃo intestinal caracterizada por elevados nÃveis de LFF, independente da presenÃa de diarrÃia e Campylobacter sp. Em conclusÃo, nossos achados corroboram dados da literatura cientÃfica relacionados à prevalÃncia de C. jejuni e C. coli na populaÃÃo infantil, existÃncia de portadores assintomÃticos e associaÃÃo entre a detecÃÃo do microorganismo e desnutriÃÃo. AlÃm disso, nossos dados apontam para ocorrÃncia de variabilidade genÃtica dentre as cepas de C. jejuni detectadas na populaÃÃo estudada em relaÃÃo à presenÃa ou ausÃncia dos genes de CDT. / Campylobacter jejuni and Campylobacter coli are important etiologic agents of worldwide diarrheal disease. Campylobacter sp. infection is usually identified by a 72 hour microbiological culture that identifies the genus of the responsible organism. Our main goal was to investigate the prevalence of C. jejuni and C. coli in children, aged 2-36 months, from urban Fortaleza, CE, Brazil, in an observational epidemiological case-control study using, as a tool of detection, the polymerase chain reaction (PCR). Our other goals were to investigate the nutritional impact of infection (cases) or colonization (controls) for Campylobacter sp., to determine the presence of three virulence genes of C. jejuni cytolethal distending toxin (CDT), and to evaluate the occurrence of inflammation in intestinal infections caused by Campylobacter sp. The study population consisted of 83 cases and 83 controls, where the cases consisted of children with a history of diarrhea in the 14 days prior to selection for the study. We assessed socioeconomic parameters through an epidemiological questionnaire. Anthropometric measurements were collected to determine z-score parameters for assessing the nutritional status of the children. Detection of Campylobacter from frozen samples was performed by enzyme-linked immunosorbent assay (ELISA) and PCR. Also, using PCR technology, we investigated the presence of C. jejuni genes cdtA, cdtB and cdtC. Intestinal inflammation was assessed by semi-quantitative ELISA detection of fecal lactoferrin (LFF). PCR technology detected C. jejuni in 9.6% of the cases (8/83) and 7.2% of the controls (6/83), while C. coli was detected in 6.0% of the cases (5/83) and 1.2% of the controls (1/83). CDT genes were found in 50% of hipO+ samples (7/14). There was a significant difference (p <0.05) in the weight for age z-scores (WAZ) and the weight for height z-scores (WHZ) between case and control carriers of C. jejuni, where case carriers showed lower average WAZ and WHZ than control carriers. Moreover, in the case group, carriers of C. jejuni showed a lower WHZ average than that of non-carrier cases of C. jejuni. More than 80.0% of the children studied had intestinal inflammation characterized by high levels of LFF regardless of the presence of diarrhea and Campylobacter sp. In conclusion, our findings corroborate data in the scientific literature related to the prevalence of C. jejuni and C. coli in pediatric populations, the existence of asymptomatic carriers and an association between the detection of the microorganism and malnutrition. In addition, our data suggest a genetic variability among the strains of C. jejuni detected in the study population, related to presence o absence of CDT genes.