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Horizontal versus familial transmission of Helicobacter pylori.

Schwarz S, Morelli G, Kusecek B, Manica A, Balloux F, Owen RJ, Graham DY, van der Merwe S, Achtman M, Suerbaum S - PLoS Pathog. (2008)

Bottom Line: Non-unique isolates were less frequent in South African families, and there was no significant correlation between kinship and similarity of H. pylori sequences.We conclude that patterns of spread of H. pylori under conditions of high prevalence, such as the rural South African families, differ from those in developed countries.The patterns observed in rural South African families may be representative of large parts of the developing world.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Microbiology and Hospital Epidemiology, Hanover Medical School, Hanover, Germany.

ABSTRACT
Transmission of Helicobacter pylori is thought to occur mainly during childhood, and predominantly within families. However, due to the difficulty of obtaining H. pylori isolates from large population samples and to the extensive genetic diversity between isolates, the transmission and spread of H. pylori remain poorly understood. We studied the genetic relationships of H. pylori isolated from 52 individuals of two large families living in a rural community in South Africa and from 43 individuals of 11 families living in urban settings in the United Kingdom, the United States, Korea, and Colombia. A 3,406 bp multilocus sequence haplotype was determined for a total of 142 H. pylori isolates. Isolates were assigned to biogeographic populations, and recent transmission was measured as the occurrence of non-unique isolates, i.e., isolates whose sequences were identical to those of other isolates. Members of urban families were almost always infected with isolates from the biogeographic population that is common in their location. Non-unique isolates were frequent in urban families, consistent with familial transmission between parents and children or between siblings. In contrast, the diversity of H. pylori in the South African families was much more extensive, and four distinct biogeographic populations circulated in this area. Non-unique isolates were less frequent in South African families, and there was no significant correlation between kinship and similarity of H. pylori sequences. However, individuals who lived in the same household did have an increased probability of carrying the same non-unique isolates of H. pylori, independent of kinship. We conclude that patterns of spread of H. pylori under conditions of high prevalence, such as the rural South African families, differ from those in developed countries. Horizontal transmission occurs frequently between persons who do not belong to a core family, blurring the pattern of familial transmission that is typical of developed countries. Predominantly familial transmission in urban societies is likely a result of modern living conditions with good sanitation and where physical contact between persons outside the core family is limited and regulated by societal rules. The patterns observed in rural South African families may be representative of large parts of the developing world.

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Helicobacter pylori in 11 families from the United States, Korea, the United Kingdom, and Colombia.Meaning of symbols and color-coding as described for Figures 1 and 2. Only one isolate was available per individual. Unique STs are shown in black and identical STs detected within a family are highlighted in red.
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ppat-1000180-g003: Helicobacter pylori in 11 families from the United States, Korea, the United Kingdom, and Colombia.Meaning of symbols and color-coding as described for Figures 1 and 2. Only one isolate was available per individual. Unique STs are shown in black and identical STs detected within a family are highlighted in red.

Mentions: As expected from their geographic locations, and in contrast to the South African families, almost all H. pylori that were isolated from each of the urban families belonged to a single population, namely hpEurope for the families in the U.S.A., England, Northern Ireland and Colombia and hpEastAsia for the families in Korea (Figure 3). (An exceptional hpAfrica1 isolate was found in the C5 family from Colombia.) Furthermore, unlike the South African families, and in concordance with prior conclusions [11], [14]–[19], at least two first degree relatives carried isolates of the same ST within 8/11 urban families. In four of these families, the patterns apparently reflected trans-generational transmission because the same STs were isolated from a parent plus a child (families K1, Ireland, and C7), or from a grandfather and his grandson (family England, 2nd degree relatives). In four other families, similar to the results from the South African families, identical STs were isolated from siblings (families H2, K3, K5, and C5) but even these may have reflected trans-generational transmission because H. pylori was only available from one parent per family and only one isolate was tested per individual. Three families (H1, H3 and C6) did not yield any non-unique STs (Figure 3).


Horizontal versus familial transmission of Helicobacter pylori.

Schwarz S, Morelli G, Kusecek B, Manica A, Balloux F, Owen RJ, Graham DY, van der Merwe S, Achtman M, Suerbaum S - PLoS Pathog. (2008)

Helicobacter pylori in 11 families from the United States, Korea, the United Kingdom, and Colombia.Meaning of symbols and color-coding as described for Figures 1 and 2. Only one isolate was available per individual. Unique STs are shown in black and identical STs detected within a family are highlighted in red.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2563686&req=5

ppat-1000180-g003: Helicobacter pylori in 11 families from the United States, Korea, the United Kingdom, and Colombia.Meaning of symbols and color-coding as described for Figures 1 and 2. Only one isolate was available per individual. Unique STs are shown in black and identical STs detected within a family are highlighted in red.
Mentions: As expected from their geographic locations, and in contrast to the South African families, almost all H. pylori that were isolated from each of the urban families belonged to a single population, namely hpEurope for the families in the U.S.A., England, Northern Ireland and Colombia and hpEastAsia for the families in Korea (Figure 3). (An exceptional hpAfrica1 isolate was found in the C5 family from Colombia.) Furthermore, unlike the South African families, and in concordance with prior conclusions [11], [14]–[19], at least two first degree relatives carried isolates of the same ST within 8/11 urban families. In four of these families, the patterns apparently reflected trans-generational transmission because the same STs were isolated from a parent plus a child (families K1, Ireland, and C7), or from a grandfather and his grandson (family England, 2nd degree relatives). In four other families, similar to the results from the South African families, identical STs were isolated from siblings (families H2, K3, K5, and C5) but even these may have reflected trans-generational transmission because H. pylori was only available from one parent per family and only one isolate was tested per individual. Three families (H1, H3 and C6) did not yield any non-unique STs (Figure 3).

Bottom Line: Non-unique isolates were less frequent in South African families, and there was no significant correlation between kinship and similarity of H. pylori sequences.We conclude that patterns of spread of H. pylori under conditions of high prevalence, such as the rural South African families, differ from those in developed countries.The patterns observed in rural South African families may be representative of large parts of the developing world.

View Article: PubMed Central - PubMed

Affiliation: Institute of Medical Microbiology and Hospital Epidemiology, Hanover Medical School, Hanover, Germany.

ABSTRACT
Transmission of Helicobacter pylori is thought to occur mainly during childhood, and predominantly within families. However, due to the difficulty of obtaining H. pylori isolates from large population samples and to the extensive genetic diversity between isolates, the transmission and spread of H. pylori remain poorly understood. We studied the genetic relationships of H. pylori isolated from 52 individuals of two large families living in a rural community in South Africa and from 43 individuals of 11 families living in urban settings in the United Kingdom, the United States, Korea, and Colombia. A 3,406 bp multilocus sequence haplotype was determined for a total of 142 H. pylori isolates. Isolates were assigned to biogeographic populations, and recent transmission was measured as the occurrence of non-unique isolates, i.e., isolates whose sequences were identical to those of other isolates. Members of urban families were almost always infected with isolates from the biogeographic population that is common in their location. Non-unique isolates were frequent in urban families, consistent with familial transmission between parents and children or between siblings. In contrast, the diversity of H. pylori in the South African families was much more extensive, and four distinct biogeographic populations circulated in this area. Non-unique isolates were less frequent in South African families, and there was no significant correlation between kinship and similarity of H. pylori sequences. However, individuals who lived in the same household did have an increased probability of carrying the same non-unique isolates of H. pylori, independent of kinship. We conclude that patterns of spread of H. pylori under conditions of high prevalence, such as the rural South African families, differ from those in developed countries. Horizontal transmission occurs frequently between persons who do not belong to a core family, blurring the pattern of familial transmission that is typical of developed countries. Predominantly familial transmission in urban societies is likely a result of modern living conditions with good sanitation and where physical contact between persons outside the core family is limited and regulated by societal rules. The patterns observed in rural South African families may be representative of large parts of the developing world.

Show MeSH
Related in: MedlinePlus