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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 family 12 from South Africa.Circles in the pedigree depict female and squares depict male family members. Numbers in the symbols refer to the patient/isolate identifyer. Empty symbols: no biopsies were taken, because individuals refused to participate or were deceased. Colours of filled symbols indicate the assignment of the isolate to H. pylori populations by Structure 2.0 analysis. Color-coding is shown on the right. Numbers below the symbols indicate the sequence type (ST) of the antrum (upper number) and corpus (lower number) isolates. STs that occurred in more than one individual are highlighted by the same colour. Black horizontal lines between upper and lower ST numbers indicate that antrum and corpus isolates were assigned to different STs. NEG: H. pylori could not be cultivated from the respective biopsy. Individuals where the upper or lower number are missing indicate that only one biopsy was available.
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ppat-1000180-g001: Helicobacter pylori in family 12 from South Africa.Circles in the pedigree depict female and squares depict male family members. Numbers in the symbols refer to the patient/isolate identifyer. Empty symbols: no biopsies were taken, because individuals refused to participate or were deceased. Colours of filled symbols indicate the assignment of the isolate to H. pylori populations by Structure 2.0 analysis. Color-coding is shown on the right. Numbers below the symbols indicate the sequence type (ST) of the antrum (upper number) and corpus (lower number) isolates. STs that occurred in more than one individual are highlighted by the same colour. Black horizontal lines between upper and lower ST numbers indicate that antrum and corpus isolates were assigned to different STs. NEG: H. pylori could not be cultivated from the respective biopsy. Individuals where the upper or lower number are missing indicate that only one biopsy was available.

Mentions: We determined the genetic relationships between H. pylori that infected two multi-generation families living in a rural area near Pretoria, South Africa. Gastric biopsies were taken from both the antrum and corpus of 45 members of family 12 (Figure 1) and 10 members of family 13 (Figure 2). Additional single biopsies from either antrum or corpus were obtained from three other members of family 12. H. pylori was cultivated from 90% of these individuals, resulting in a total of 99 isolates from 52 individuals: paired isolates from antrum and corpus of 47 individuals, and a single isolate from either corpus or antrum from five individuals. Each isolate was subjected to multilocus sequence typing, resulting in a multilocus haplotype of 3,406 bp after concatenation of the sequences of fragments of seven housekeeping genes. These haplotypes were then assigned to one of the four modern H. pylori populations hpEurope, hpAfrica1, hpAfrica2 or hpAsia2 [3],[12] by the Bayesian program Structure 2.0 (Figures 1 and 2). None of the haplotypes from these families belonged to the hpEastAsia or hpNEAfrica populations.


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 family 12 from South Africa.Circles in the pedigree depict female and squares depict male family members. Numbers in the symbols refer to the patient/isolate identifyer. Empty symbols: no biopsies were taken, because individuals refused to participate or were deceased. Colours of filled symbols indicate the assignment of the isolate to H. pylori populations by Structure 2.0 analysis. Color-coding is shown on the right. Numbers below the symbols indicate the sequence type (ST) of the antrum (upper number) and corpus (lower number) isolates. STs that occurred in more than one individual are highlighted by the same colour. Black horizontal lines between upper and lower ST numbers indicate that antrum and corpus isolates were assigned to different STs. NEG: H. pylori could not be cultivated from the respective biopsy. Individuals where the upper or lower number are missing indicate that only one biopsy was available.
© Copyright Policy
Related In: Results  -  Collection

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

ppat-1000180-g001: Helicobacter pylori in family 12 from South Africa.Circles in the pedigree depict female and squares depict male family members. Numbers in the symbols refer to the patient/isolate identifyer. Empty symbols: no biopsies were taken, because individuals refused to participate or were deceased. Colours of filled symbols indicate the assignment of the isolate to H. pylori populations by Structure 2.0 analysis. Color-coding is shown on the right. Numbers below the symbols indicate the sequence type (ST) of the antrum (upper number) and corpus (lower number) isolates. STs that occurred in more than one individual are highlighted by the same colour. Black horizontal lines between upper and lower ST numbers indicate that antrum and corpus isolates were assigned to different STs. NEG: H. pylori could not be cultivated from the respective biopsy. Individuals where the upper or lower number are missing indicate that only one biopsy was available.
Mentions: We determined the genetic relationships between H. pylori that infected two multi-generation families living in a rural area near Pretoria, South Africa. Gastric biopsies were taken from both the antrum and corpus of 45 members of family 12 (Figure 1) and 10 members of family 13 (Figure 2). Additional single biopsies from either antrum or corpus were obtained from three other members of family 12. H. pylori was cultivated from 90% of these individuals, resulting in a total of 99 isolates from 52 individuals: paired isolates from antrum and corpus of 47 individuals, and a single isolate from either corpus or antrum from five individuals. Each isolate was subjected to multilocus sequence typing, resulting in a multilocus haplotype of 3,406 bp after concatenation of the sequences of fragments of seven housekeeping genes. These haplotypes were then assigned to one of the four modern H. pylori populations hpEurope, hpAfrica1, hpAfrica2 or hpAsia2 [3],[12] by the Bayesian program Structure 2.0 (Figures 1 and 2). None of the haplotypes from these families belonged to the hpEastAsia or hpNEAfrica populations.

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