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Does typing of Chlamydia trachomatis using housekeeping multilocus sequence typing reveal different sexual networks among heterosexuals and men who have sex with men?

Versteeg B, Bruisten SM, van der Ende A, Pannekoek Y - BMC Infect. Dis. (2016)

Bottom Line: Using the adapted MLST-7 scheme, full MLST profiles were obtained for 187 of 188 tested specimens resulting in a high success rate of 99.5 %.Minimum spanning tree analyses was used to examine the clustering of MLST-7 data, which showed no reflection of separate transmission in MSM and heterosexual hosts.Moreover, typing using the hr-MLST-6 scheme identified genetically related clusters within each of clusters that were identified by using the MLST-7 scheme.

View Article: PubMed Central - PubMed

Affiliation: Public Health Laboratory, Cluster Infectious Diseases, Public Health Service Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Background: Chlamydia trachomatis infections remain the most common bacterial sexually transmitted infection worldwide. To gain more insight into the epidemiology and transmission of C. trachomatis, several schemes of multilocus sequence typing (MLST) have been developed. We investigated the clustering of C. trachomatis strains derived from men who have sex with men (MSM) and heterosexuals using the MLST scheme based on 7 housekeeping genes (MLST-7) adapted for clinical specimens and a high-resolution MLST scheme based on 6 polymorphic genes, including ompA (hr-MLST-6).

Methods: Specimens from 100 C. trachomatis infected men who have sex with men (MSM) and 100 heterosexual women were randomly selected from previous studies and sequenced. We adapted the MLST-7 scheme to a nested assay to be suitable for direct typing of clinical specimens. All selected specimens were typed using both the adapted MLST-7 scheme and the hr-MLST-6 scheme. Clustering of C. trachomatis strains derived from MSM and heterosexuals was assessed using minimum spanning tree analysis.

Results: Sufficient chlamydial DNA was present in 188 of the 200 (94 %) selected samples. Using the adapted MLST-7 scheme, full MLST profiles were obtained for 187 of 188 tested specimens resulting in a high success rate of 99.5 %. Of these 187 specimens, 91 (48.7 %) were from MSM and 96 (51.3 %) from heterosexuals. We detected 21 sequence types (STs) using the adapted MLST-7 and 79 STs using the hr-MLST-6 scheme. Minimum spanning tree analyses was used to examine the clustering of MLST-7 data, which showed no reflection of separate transmission in MSM and heterosexual hosts. Moreover, typing using the hr-MLST-6 scheme identified genetically related clusters within each of clusters that were identified by using the MLST-7 scheme.

Conclusion: No distinct transmission of C. trachomatis could be observed in MSM and heterosexuals using the adapted MLST-7 scheme in contrast to using the hr-MLST-6. In addition, we compared clustering of both MLST schemes and demonstrated that typing using the hr-MLST-6 scheme is able to identify genetically related clusters of C. trachomatis strains within each of the clusters that were identified by using the MLST-7 scheme.

No MeSH data available.


Related in: MedlinePlus

Minimum spanning tree showing the clustering of 187 Chlamydia trachomatis-positive specimens from MSM and heterosexuals. Each circle represents one ST. Size of the circles is proportional to the number of identical ST profiles. Bold lines connect types that differ for one single locus. Halos indicate the distinct clusters. a Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the MLST-7 scheme; b Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the hr-MLST-6 scheme. The colour coding is: red, men who have sex with men (n = 91); green, heterosexuals (n = 96)
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Fig1: Minimum spanning tree showing the clustering of 187 Chlamydia trachomatis-positive specimens from MSM and heterosexuals. Each circle represents one ST. Size of the circles is proportional to the number of identical ST profiles. Bold lines connect types that differ for one single locus. Halos indicate the distinct clusters. a Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the MLST-7 scheme; b Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the hr-MLST-6 scheme. The colour coding is: red, men who have sex with men (n = 91); green, heterosexuals (n = 96)

Mentions: A minimum spanning tree was generated based on the MLST-7 STs and 3 large clusters (A-C) could be identified (Fig. 1a). The number of specimens in these clusters ranged from 18 to 94 and included all typed specimens so no single isolates (singletons) or small clusters were identified. The minimum spanning tree showed mixed clusters of specimens from MSM and heterosexual individuals and a low genetic diversity among the C. trachomatis population. Cluster A contained 41 specimens from MSM (54.7 %) that were associated with 3 STs (Table 2). Two of those STs (ST131, ST148) were found in one MSM specimen each, whereas the remaining ST (ST132) was found in specimens from 52 individuals of whom 39 (75.0 %) where MSM. Cluster B contained 32 specimens from MSM (34.0 %) that were associated with 3 STs (ST97, ST133, ST134). Of those, ST97 was found in 42 specimens from individuals of whom 25 (59.5 %) were MSM, ST133 was found in specimens from 26 individuals of whom 6 were MSM and ST134 was found in specimens from 2 individuals of whom 1 was MSM. Cluster C solely consisted of specimens from MSM which were all associated with the same ST (ST44).Fig. 1


Does typing of Chlamydia trachomatis using housekeeping multilocus sequence typing reveal different sexual networks among heterosexuals and men who have sex with men?

Versteeg B, Bruisten SM, van der Ende A, Pannekoek Y - BMC Infect. Dis. (2016)

Minimum spanning tree showing the clustering of 187 Chlamydia trachomatis-positive specimens from MSM and heterosexuals. Each circle represents one ST. Size of the circles is proportional to the number of identical ST profiles. Bold lines connect types that differ for one single locus. Halos indicate the distinct clusters. a Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the MLST-7 scheme; b Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the hr-MLST-6 scheme. The colour coding is: red, men who have sex with men (n = 91); green, heterosexuals (n = 96)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4836166&req=5

Fig1: Minimum spanning tree showing the clustering of 187 Chlamydia trachomatis-positive specimens from MSM and heterosexuals. Each circle represents one ST. Size of the circles is proportional to the number of identical ST profiles. Bold lines connect types that differ for one single locus. Halos indicate the distinct clusters. a Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the MLST-7 scheme; b Minimum spanning tree showing the clustering of the C. trachomatis-positive specimens according to the hr-MLST-6 scheme. The colour coding is: red, men who have sex with men (n = 91); green, heterosexuals (n = 96)
Mentions: A minimum spanning tree was generated based on the MLST-7 STs and 3 large clusters (A-C) could be identified (Fig. 1a). The number of specimens in these clusters ranged from 18 to 94 and included all typed specimens so no single isolates (singletons) or small clusters were identified. The minimum spanning tree showed mixed clusters of specimens from MSM and heterosexual individuals and a low genetic diversity among the C. trachomatis population. Cluster A contained 41 specimens from MSM (54.7 %) that were associated with 3 STs (Table 2). Two of those STs (ST131, ST148) were found in one MSM specimen each, whereas the remaining ST (ST132) was found in specimens from 52 individuals of whom 39 (75.0 %) where MSM. Cluster B contained 32 specimens from MSM (34.0 %) that were associated with 3 STs (ST97, ST133, ST134). Of those, ST97 was found in 42 specimens from individuals of whom 25 (59.5 %) were MSM, ST133 was found in specimens from 26 individuals of whom 6 were MSM and ST134 was found in specimens from 2 individuals of whom 1 was MSM. Cluster C solely consisted of specimens from MSM which were all associated with the same ST (ST44).Fig. 1

Bottom Line: Using the adapted MLST-7 scheme, full MLST profiles were obtained for 187 of 188 tested specimens resulting in a high success rate of 99.5 %.Minimum spanning tree analyses was used to examine the clustering of MLST-7 data, which showed no reflection of separate transmission in MSM and heterosexual hosts.Moreover, typing using the hr-MLST-6 scheme identified genetically related clusters within each of clusters that were identified by using the MLST-7 scheme.

View Article: PubMed Central - PubMed

Affiliation: Public Health Laboratory, Cluster Infectious Diseases, Public Health Service Amsterdam, Amsterdam, The Netherlands.

ABSTRACT

Background: Chlamydia trachomatis infections remain the most common bacterial sexually transmitted infection worldwide. To gain more insight into the epidemiology and transmission of C. trachomatis, several schemes of multilocus sequence typing (MLST) have been developed. We investigated the clustering of C. trachomatis strains derived from men who have sex with men (MSM) and heterosexuals using the MLST scheme based on 7 housekeeping genes (MLST-7) adapted for clinical specimens and a high-resolution MLST scheme based on 6 polymorphic genes, including ompA (hr-MLST-6).

Methods: Specimens from 100 C. trachomatis infected men who have sex with men (MSM) and 100 heterosexual women were randomly selected from previous studies and sequenced. We adapted the MLST-7 scheme to a nested assay to be suitable for direct typing of clinical specimens. All selected specimens were typed using both the adapted MLST-7 scheme and the hr-MLST-6 scheme. Clustering of C. trachomatis strains derived from MSM and heterosexuals was assessed using minimum spanning tree analysis.

Results: Sufficient chlamydial DNA was present in 188 of the 200 (94 %) selected samples. Using the adapted MLST-7 scheme, full MLST profiles were obtained for 187 of 188 tested specimens resulting in a high success rate of 99.5 %. Of these 187 specimens, 91 (48.7 %) were from MSM and 96 (51.3 %) from heterosexuals. We detected 21 sequence types (STs) using the adapted MLST-7 and 79 STs using the hr-MLST-6 scheme. Minimum spanning tree analyses was used to examine the clustering of MLST-7 data, which showed no reflection of separate transmission in MSM and heterosexual hosts. Moreover, typing using the hr-MLST-6 scheme identified genetically related clusters within each of clusters that were identified by using the MLST-7 scheme.

Conclusion: No distinct transmission of C. trachomatis could be observed in MSM and heterosexuals using the adapted MLST-7 scheme in contrast to using the hr-MLST-6. In addition, we compared clustering of both MLST schemes and demonstrated that typing using the hr-MLST-6 scheme is able to identify genetically related clusters of C. trachomatis strains within each of the clusters that were identified by using the MLST-7 scheme.

No MeSH data available.


Related in: MedlinePlus