Spread of clonal genovar E Chlamydia trachomatis among men who have sex with men

In a previous study, we developed a Multi-Locus VNTRs Analysis (MLVA) typing system, called MLVA-5, for the discrimination of Chlamydia trachomatis genovar E strain. The results suggested the clonal spread of a MLVA-5 type 21 strain among men who have sex with men (MSM). We applied the MLVA-5 typing method on 157 French anorectal genovar E specimens and 19 Swedish specimens collected between 2010 and 2015. A total of 29 MLVA-5 types was obtained, with three predominant types among French samples: 78 specimens belonged to MLVA-5 type 21, two other types, 11 and 13, included 9 and 14 specimens, respectively. In 15 cases, one unique MLVA-5 type was observed for a single patient, 7 of which were new types not previously described. The distribution of MLVA-5 types according to sexual orientation showed that the 7 anorectal specimens from heterosexual patients belonged to 6 genotypes, and the 12 anorectal specimens from bisexual patients comprised eight types. The 95 anorectal specimens from MSM were distributed into 22 types, but 55 (57.9%) of them belonged to MLVA-5 type 21. Among the Swedish specimens from MSM, eight were from MLVA-type 21 (4 urines and 4 anorectal specimens). The results support the hypothesis of the spread of clonal genovar E strain among MSM.

Genotyping of Chlamydia Abortus Using Multiple Loci Variable Number of Tandem Repeats Analysis Technique

Background: The correlation between various factors (geographical region, clinical incidence, and host type) and the genomic heterogeneity has been shown in several bacterial strains including Chlamydia abortus. Methods: The aim of this study was to survey the predominant types of C. abortus strains isolated from ruminants in Iran by the multiple loci variable number of tandem repeats (VNTR) analysis (MLVA) method. C. abortus infection was evaluated in a total of 117 aborted fetuses by real-time PCR. The isolation was done via the inoculation of the positive samples in chicken embryo and the L929 cell line. Genotyping was carried out by MLVA typing technique. Results: Forty samples (34.2%) were detected with C. abortus infection; however, chlamydial infection in ruminants of Charmahal/Bakhtiari (3 bovines and 35 sheep) was higher than that of Khuzestan (2 sheep). All MLVA types (MT1-MT8) were detected in the collected samples from Charmahal/Bakhtiari but only 2 types (MT1 and MT3) were reported in samples from Khuzestan. The main MT type was MT1 (32% of samples). Although in this study only 9 cow samples were investigated, they possessed similar clusters to those obtained from sheep (MT1 and MT6).Variation of type in sheep samples (MT1 to MT8) was more than that of bovine samples (MT1, and MT6); this can be attributed to the fact that more samples of sheep were studied as against the bovine samples. Conclusion: Although the difference between the detected same MT types in several animal species or between 2 geographic areas is significant, comprehensive studies are still needed. In Iran, due to traditional intercourse between animals of different provinces, the spread of other types is typically highly probable.

VNTR loci as indicators of proline-dependent plague microbe strains (Yersinia pestis) in the central caucasian mountain natural plague focus

Y. pestis MLVA typing is used both to seek for similarities and differences between individual isolates upon conducting epidemiological investigations as well as for clonal clustering of intraspecies phylogenetic groups while analyzing microevolution and taxonomy issues. It cannot be ruled out that the most variable loci may be indicators allowing to approximate the unique strain-related properties circulating in certain natural plague foci. The Central Caucasian Highland Natural Plague Focus distinguished by heterogeneity of the circulating strains therein, including proline pro- and auxo-trophy, may represent a convenient model for testing this hypothesis. The purpose of our work was to assess the frequencies of the VNTR alleles associated with proline dependence among the Y. pestis strain VNTR loci, determined during previous MLVA-25 typing in the Central Caucasian Highland Natural Plague Focus. The main task was to identify the most informative sets of VNTR loci suitable for predicting proline pro— and auxotrophy (pro+, pro—). It was found that the loci ms45, ms56, ms46, ms07, ms69, ms62 displayed peak variability by allele frequencies and/or exhibited significant differences of mean allele frequencies in the pro— and pro+ strains. In particular, it was showed that the alleles of the ms45 locus contained 6 tandem repeats suggesting probability for pro+ reaching 0.944, whereas the alleles of the ms45 locus contained 7 tandem repeats with expected probability for pro— reaching 0.783. Moreover, the ms56 and ms46 contained 9 and more than 18 tandem repeats, respectively, thereby pointing at probability for pro+ equal to 0.933 and 0.818, respectively. Diagnostics for pro+/pro— phenotype by using specific statistical methods demonstrated statistical error 13.33% and 26.67% for the pro— and pro+ strains, respectively. All pro+ strains bearing a 6 tandem repeat complex from the ms45 locus, 9 tandem repeats derived from the ms56 locus and ms46 locus-derived 29—30 tandem repeats were accurately diagnosed solely based on these 3 loci. Thus, it is possible to predict some properties of Y. pestis strains based on determining the allele frequencies. While the number of MLVA typed plaque strains isolated in such natural focus has been progressively increased, it may be expected that opportunities for prognosing their properties based on determining locus tandem repeat composition having diagnostic value would be elevated.

New Genotypes of Coxiella burnetii Circulating in Brazil and Argentina

Coxiella burnetii, the zoonotic agent of Q fever, has a worldwide distribution. Despite the vast information about the circulating genotypes in Europe and North America, there is a lack of data regarding C. burnetii strains in South America. Here, we show the presence of novel multispacer sequence typing (MST) genotypes of C. burnetii in two clusters detected in Brazil and Argentina that seem to be distant in parenthood. Argentinian strains isolated from a tick belongs to a new phylogenetic branch of C. burnetii, and the Brazilians strains may be related to MST 20 and 61. Multilocus variable number tandem repeats analysis (MLVA) typing provided a deeper resolution that may be related to host clusters of bovines, caprine, ovine, and ticks. Our results corroborate with the reports of geotypes of C. burnetii. Thus, we highlight the need for more genotyping studies to understand the genetic diversity of C. burnetii in South America and to confirm the hypothesis of host-related genotypes. We also emphasize the importance of virulence studies for a better understanding of Q fever in the region, which may help in surveillance and disease prevention programs.

Development of genotyping method of the glanders causative agent based on multiple locus variable-number tandem repeat analysis

The aim was to develop a short MLVA-typing scheme of the causative agent of glanders and to assess the possibility of its use for differentiation of Burkholderia mallei strains and study their genetic polymorphism.Materials and methods. The study was carried out on 14 B. mallei strains from the collection of the Volgograd Research Institute for Plague Control and 12 whole genome sequences of the B. mallei strains presented in GenBank NCBI. A set of 32 loci proposed for differentiation of the melioidosis pathogen was used to select VNTR-loci for typing the causative agent of glanders. Polyacrylamide gel electrophoresis, sequencing, and fragment analysis were applied to detect the size of the VNTR fragments.Results. VNTR loci 993, 3145, 3652, 20, 2862, and 1217, which were selected as the most variable among the causative agent of glanders, were included in the final MLVA typing scheme. The parameters of setting and detecting the results of MLVA typing have been optimized.Conclusion. Analisys of the typing results of 26 B. mallei strains showed a high discriminating power of the developed method of intraspecies differentiation of glanders pathogen based on 6-loci MLVA-scheme and the prospects of its use for epidemiological investigation to determine the source of the glanders outbreak.