Helicobacter pylori genome variability in a framework of familial transmission

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori </it>infection is exceptionally prevalent and is considered to be acquired primarily early in life through person-to-person transmission within the family. <it>H. pylori </it>is a genetically diverse bacterial species, which may facilitate adaptation to new hosts and persistence for decades. The present study aimed to explore the genetic diversity of clonal isolates from a mother and her three children in order to shed light on <it>H. pylori </it>transmission and host adaptation.</p> <p>Results</p> <p>Two different <it>H. pylori </it>strains and strain variants were identified in the family members by PCR-based molecular typing and sequencing of five loci. Genome diversity was further assessed for 15 isolates by comparative microarray hybridizations. The microarray consisted of 1,745 oligonucleotides representing the genes of two previously sequenced <it>H. pylori </it>strains. The microarray analysis detected a limited mean number (± standard error) of divergent genes between clonal isolates from the same and different individuals (1 ± 0.4, 0.1%, and 3 ± 0.3, 0.2%, respectively). There was considerable variability between the two different strains in the family members (147 ± 4, 8%) and for all isolates relative to the two sequenced reference strains (314 ± 16, 18%). The diversity between different strains was associated with gene functional classes related to DNA metabolism and the cell envelope.</p> <p>Conclusion</p> <p>The present data from clonal <it>H. pylori </it>isolates of family members do not support that transmission and host adaptation are associated with substantial sequence diversity in the bacterial genome. However, important phenotypic modifications may be determined by additional genetic mechanisms, such as phase-variation. Our findings can aid further exploration of <it>H. pylori </it>genetic diversity and adaptation.</p

Människans hälsa och ohälsa

Föreliggande uppsatser med det övergripande namnet "Människans hälsa och ohälsa" är utarbetade med utgångspunkt från föredrag vid en KVVS-konferens med samma titel som ägde rum i oktober 2011. I dessa uppsatser behandlas olika problemområden med anknytning till hälsa och ohälsa hos människan. Socialmedicinska frågor som mortalitet, dödsorsaker och morbiditet ges en övergripande beskrivning. Personlig vård inom medicinen kontra regelverk i form av generella riktlinjer beskrivs som delvis kolliderande strategier. Vaccinationsproblematiken diskuteras utifrån erfarenheter från de influensapandemier som drabbar världen med viss regelbundenhet. Smärta och smärtupplevelser behandlas utifrån historiska, diagnostiska och behandlingsmässiga aspekter. Rollen hos brunt fett i vävnader diskuteras utifrån bl.a. nya angreppssätt att komma tillrätta med övervikt och diabetes. Sambanden mellan kostmönster och uppkomst av hjärt-kärlsjukdomar och cancer utreds. En sista uppsats berör fettsyror i bröstmjölk och hur spädbarn tar upp dessa med implikationer för uppkomsten av olika livsstilssjukdomar i vuxen ålder, s.k. epigenetik

Transmission Studies of Babesia microti in Ixodes ricinus Ticks and Gerbils

In order to investigate the possible role of Ixodes ricinus as a vector of zoonotic Babesia microti infection in Europe, a European rodent isolate (HK) and a zoonotic American isolate (GI) were studied in transmission experiments. PCR detected B. microti in the blood and spleens of infected gerbils (Meriones unguiculatus) and also in laboratory-induced infections of I. ricinus ticks. B. microti DNA was detected by PCR in all pooled samples of nymphs and the majority of adults that had fed as larvae and nymphs, respectively, on gerbils with acute infection of the European isolate, confirming that I. ricinus could serve as a vector in Europe. The American isolate, GI, proved to be equally infective for larval and nymphal I. ricinus as the HK strain, despite a very different appearance in gerbil erythrocytes. Nymphs infected with the HK and GI strains readily infected gerbils. In contrast to the finding in acute infections, ticks that fed on gerbils with chronic infections of HK and GI did not become infected. It was also found that the HK strain was not transmitted transovarially. The finding that a B. microti strain (GI) from a distant geographical region (United States) can infect and be transmitted by I. ricinus suggests that other European B. microti strains, in addition to the HK strain used here, are probably infective for I. ricinus, supporting the view that infection of humans with European B. microti may be a regular occurrence

Seroprevalence of Helicobacter pylori Infection in Urban and Rural Vietnam

Helicobacter pylori-associated diseases, such as peptic ulcer and gastric cancer, are common in Vietnam, but the prevalence of the infection is largely unknown. A validated enzyme-linked immunosorbent assay was used for seroepidemiology with 971 samples from the general population, ages 0 to 88 years, with 546 samples from an urban population (Hanoi), and with 425 samples from a poor, rural province (Hatay). The overall seroprevalence of the infection was 746 per 1,000, with a prevalence of 788 per 1,000 in Hanoi and 692 per 1,000 in Hatay (P = 0.0007). The risk for infection in the rural area of Hatay was 40% lower than in the urban population of Hanoi, with the odds ratio being 0.59 (95% confidence interval, 0.43 to 0.81). The study shows that the prevalence of H. pylori infection is high in Vietnam and especially high in a large urban area, such as the city of Hanoi

Enzyme-Linked Immunosorbent Assay for Helicobacter pylori Needs Adjustment for the Population Investigated

Helicobacter pylori infection and peptic ulcer disease are common in developing countries, e.g., Vietnam. An enzyme-linked immunosorbent assay (ELISA) for screening of patients and for seroepidemiology is a useful tool but needs to be validated in the population studied. We used in-house ELISA with sonicated Swedish and Vietnamese strains as antigens to measure immunoglobulin G antibodies after absorption with sonicated Campylobacter jejuni in sera from 270 H. pylori culture-confirmed peptic ulcer patients, 128 Swedish urea-breath test and immunoblot-positive healthy controls, and 432 Vietnamese immunoblot-positive population controls. Sonicated whole-cell antigen based on the local strains showed a significantly better performance. Immunoblot-positive peptic ulcer patients had significantly higher antibody concentrations than immunoblot-positive population controls, necessitating a lower cutoff level if serology is used for screening or epidemiological purposes. The study shows that the parameters of ELISA for H. pylori need to be adjusted for the population being investigated