Overview of the phytomedicine approaches against Helicobacter pylori

Helicobacter pylori (H. pylori) successfully colonizes the human stomach of the majority of the human population. This infection always causes chronic gastritis, but may evolve to serious outcomes, such as peptic ulcer, gastric carcinoma or mucosa-associated lymphoid tissue lymphoma. H. pylori first line therapy recommended by the Maastricht-4 Consensus Report comprises the use of two antibiotics and a proton-pomp inhibitor, but in some regions failure associated with this treatment is already undesirable high. Indeed, treatment failure is one of the major problems associated with H. pylori infection and is mainly associated with bacterial antibiotic resistance. In order to counteract this situation, some effort has been allocated during the last years in the investigation of therapeutic alternatives beyond antibiotics. These include vaccines, probiotics, photodynamic inactivation and phage therapy, which are briefly revisited in this review. A particular focus on phytomedicine, also described as herbal therapy and botanical therapy, which consists in the use of plant extracts for medicinal purposes, is specifically addressed, namely considering its history, category of performed studies, tested compounds, active principle and mode of action. The herbs already experienced are highly diverse and usually selected from products with a long history of employment against diseases associated with H. pylori infection from each country own folk medicine. The studies demonstrated that many phytomedicine products have an anti-H. pylori activity and gastroprotective action. Although the mechanism of action is far from being completely understood, current knowledge correlates the beneficial action of herbs with inhibition of essential H. pylori enzymes, modulation of the host immune system and with attenuation of inflammation

The role of Helicobacter pylori outer membrane proteins in adherence and pathogenesis

Helicobacter pylori is one of the most successful human pathogens, whichcolonizes the mucus layer of the gastric epithelium of more than 50% of the world’spopulation. This curved, microaerophilic, Gram-negative bacterium induces a chronicactive gastritis, often asymptomatic, in all infected individuals. In some cases, this gastritisevolves to more severe diseases such as peptic ulcer disease, gastric adenocarcinoma, andgastric mucosa-associated lymphoid tissue lymphoma. H. pylori has developed a unique setof factors, actively supporting its successful survival and persistence in its natural hostileecological niche, the human stomach, throughout the individual’s life, unless treated. In thehuman stomach, the vast majority of H. pylori cells are motile in the mucus layer lining,but a small percentage adheres to the epithelial cell surfaces. Adherence to the gastricepithelium is important for the ability of H. pylori to cause disease because this intimateattachment facilitates: (1) colonization and persistence, by preventing the bacteria frombeing eliminated from the stomach, by mucus turnover and gastric peristalsis; (2) evasionfrom the human immune system and (3) efficient delivery of proteins into the gastric cell,such as the CagA oncoprotein. Therefore, bacteria with better adherence propertiescolonize the host at higher densities. H. pylori is one of the most genetically diversebacterial species known and is equipped with an extraordinarily large set of outermembrane proteins, whose role in the infection and persistence process will be discussed in this review, as well as the different receptor structures that have been so far described for mucosal adherence

Clostridium difficile: diversidade genética e perfis de suscetibilidade aos antimicrobianos

Este trabalho teve como objetivo estudar a variabilidade genética e o perfil de suscetibilidade aos antimicrobianos de estirpes de C. difficile recebidas no Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) entre julho de 2012 e dezembro de 2014

High worldwide conservation of a Helicobacter pylori outer membrane protein

The genetic diversity and evolution of homD, coding for Helicobacter pylori outer membrane protein (OMP) was investigated in a panel of approximately 200 clinical and reference strains, isolated from patients from different geographical origins and presenting different gastric diseases. PCR, sequencing and bioinformatics analyses were used. The homD gene was present in all strains, at a conserved locus, and showed a low genomic diversity, displaying high similarity at both nucleotide and amino acid level. A similarity plot analysis also showed a high level of sequence conservation, although a small region (~30 nucleotides) differed between Western strains and the other strains (East Asian/Ameridian and African). This region was also found in some allelic variants of another hom family member, the homC gene, suggesting the existence of recombination events between these two OMP encoding genes. Sequence analysis of the HomD predicted protein showed a N terminus region with a variable number of KP motif repeats (2 9 KP), with a correlation between the lowest number of KP motif repeats (£4 KP) and peptic ulcer disease and the highest number of repeats (£7 KP) and gastritis. In silico analysis of the HomD protein showed that the region of KP motif repeats exhibits a strong hydrophilicity and antigenicity and a high probability of being exposed to the bacterial surface, suggesting that HomD is immunogenic. These results suggest that homD gene is an important H. pylori antigen and, because of its high global conservation, it is likely to constitute a new vaccine target

A 475 years-old founder effect involving IL12RB1: a highly prevalent mutation conferring Mendelian susceptibility to mycobacterial diseases in European descendants

Mutations in IFNGR1, IFNGR2, IL12RB1, IL12B, STAT1 and NEMO result in a common clinical phenotype known as Mendelian Susceptibility to Mycobacterial Diseases (MSMD). Interleukin-12 receptor 01 (IL12R beta 1) deficiency is the most common genetic etiology for MSMD. Known mutations affecting IL12RB1 are recessively inherited and are associated with null response to both IL-12 and IL-23. Mutation IL12RB1 1623_1624delinsTT was originally described in 5 families from European origin (2 from Germany: I from Cyprus, France and Belgium). Interestingly, this same mutation was found in an unexpectedly high prevalence among IL-12R beta 1 deficient patients in Argentina: 5-out-of-6 individuals born to unrelated families carried this particular change. To determine whether mutation 1623_1624delinsTT represents a DNA mutational hotspot or a founder effect, 34 polymorphic markers internal or proximal to IL12RB1 were studied in the Argentinean and the Belgian patients. A common haplotype spanning 1.45-3.51 Mb was shared by all chromosomes carrying mutation 1623_1624delinsTT, and was not detected on 100 control chromosomes. Applying a modified likelihood-based method the age of the most recent common ancestor carrying mutation 1623_1624delinsTT was estimated in 475 years (95% CI, 175-1275), which is the time when the Spaniards initiated the colonization of the Americas. Mutation 1623_1624delinsTT represents the first founder effect described on IL-12R beta 1, the most frequently affected gene in MSMD, and affecting patients with European ancestors. The reason(s) behind the persistency of this mutation across multiple generations, its relative high prevalence, and any potential selective advantage are yet to be established

Positive selection in the evolution of Helicobacter pylori outer membrane proteins

Homologous recombination in Helicobacter pylori has been extensively described to occur via Outer Membrane Proteins (OMPs), regulating protein expression and generating allelic diversity, while the importance of single nucleotide polymorphisms (SNP) remains little studied. We used an OMP-encoding gene, homC, as a model to evaluate the weight of positive selection in the evolution of H. pylori, by using G200 sequences obtained from strains collected worldwide. N-site and branch-site phylogenetic analysis by maximum likelihood models were used to identify specific codons that may be important in homC evolution, and to evaluate the impact of selective pressure on the geographic segregation of strains, respectively. The N-site overall analysis showed that 14 of the 742 (1.9%) homC codons are likely under positive selection (likelihood-ratio test (LRT), p < 10-61). Four of these codons are located in the most variable allelic gene middle region, probably reflecting recombination-derived hitchhiking events. On the other hand, eight codons are located in the more conserved 5¢and 3¢ gene regions, although the significance of this distribution remains to be clarified. Branch-site analysis revealed 36 codons (4.9%) under positive selection (LRT, p < 10-41), showing a non-random distribution, and 89% of these particular codons (p < 10-3) support the phylogenetic segregation of European strains from both African and East Asian strains. The lack of visible recombination within this segment suggests an important biological role of point mutations in the evolution of H. pylori OMPs. In conclusion, homC SNP analysis suggests that, besides recombination, positive selection contributes as well to the evolution of H. pylori OMPs

Genetic diversity and antibiotic resistance of Arcobacter butzleri isolated from poultry and slaughterhouse environment in Portugal

Arcobacter is considered an emerging enteric pathogen, commonly associated with diarrhea, abdominal pain and in some cases with bacteriemia. This genus is widely distributed, with fteen species identi ed to date, of which the most common is Arcobacter butzleri. Arcobacter spp. has been isolated from environmental, animal, food and human samples, but poultry is considered its main reservoir. The extended use of antibiotics for disease control in modern food animal production, leads to a spread of resistant pathogenic bacteria, and Arcobacter spp. is no exception to this rule. In this study, 43 A. butzleri isolates were obtained from poultry and environment samples at a Portuguese slaughterhouse, also three reference strains were included. All isolates were con rmed at species level by multiplex PCR; genomic DNA ngerprints of all isolates were determined using Pulsed Field Gel Electrophoresis (PFGE) after enzymatic digestion with SmaI. Resistance pro les to nine antibiotics were assessed by broth microdilution method. Fifteen unique and 11 common PFGE ngerprints were identi ed among the 43 Arcobacter isolates studied, generating a total of 26 di erent PFGE ngerprints. This data demonstrates the high genetic diversity observed among Arcobacter isolates. Concerning the antibiotic susceptibility, all isolates tested were susceptible to gentamycin and one strain presented resistance to chloramphenicol. In contrast, 24 of the 43 isolates (55.8%) were resistant to cipro oxacin. All the studied isolates presented resistance to multiple antibiotics simultaneously, especially to ampicillin, vancomycin, trimethoprim, piperacillin, cefoperazone and amoxicillin. The results showed that A. butzleri isolated in Portugal presents a high genetic diversity, but also show high levels of resistance to several antimicrobial agents, this fact could represent a potential health hazard for humans through food chain contamination