1
|
Feodorova VA, Zaitsev SS, Lyapina AM, Kichemazova NV, Saltykov YV, Khizhnyakova MA, Evstifeev VV, Larionova OS. Whole genome sequencing characteristics of Chlamydia psittaci caprine AMK-16 strain, a promising killed whole cell veterinary vaccine candidate against chlamydia infection. PLoS One 2023; 18:e0293612. [PMID: 37903115 PMCID: PMC10615304 DOI: 10.1371/journal.pone.0293612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 11/01/2023] Open
Abstract
Chlamydia psittaci is a primary zoonotic pathogen with a broad host range causing severe respiratory and reproductive system infection in animals and humans. To reduce the global burden of C. psittaci-associated diseases on animal welfare and health and to control the pathogen spread in husbandry, effective vaccines based on promising vaccine candidate(s) are required. Recently, the caprine C. psittaci AMK-16 strain (AMK-16) demonstrated a high level of protection (up to 80-100%) in outbred mice and pregnant rabbits immunized with these formaldehyde-inactivated bacteria against experimental chlamydial wild-type infection. This study investigated the molecular characteristics of AMK-16 by whole-genome sequencing followed by molecular typing, phylogenetic analysis and detection of main immunodominant protein(s) eliciting the immune response in mouse model. Similarly to other C. psittaci, AMK-16 harbored an extrachromosomal plasmid. The whole-genome phylogenetic analysis proved that AMK-16 strain belonging to ST28 clustered with only C. psittaci but not with Chlamydia abortus strains. However, AMK-16 possessed the insert which resulted from the recombination event as the additional single chromosome region of a 23,100 bp size with higher homology to C. abortus (98.38-99.94%) rather than to C. psittaci (92.06-92.55%). At least six of 16 CDSs were absent in AMK-16 plasticity zone and 41 CDSs in other loci compared with the reference C. psittaci 6BC strain. Two SNPs identified in the AMK-16 ompA sequence resulted in MOMP polymorphism followed by the formation of a novel genotype/subtype including three other C. psittaci strains else. AMK-16 MOMP provided marked specific cellular and humoral immune response in 100% of mice immunized with the inactivated AMK-16 bacteria. Both DnaK and GrpE encoded by the recombination region genes were less immunoreactive, inducing only a negligible T-cell murine immune response, while homologous antibodies could be detected in 50% and 30% of immunized mice, respectively. Thus, AMK-16 could be a promising vaccine candidate for the development of a killed whole cell vaccine against chlamydiosis in livestock.
Collapse
Affiliation(s)
- Valentina A. Feodorova
- Laboratory for Fundamental and Applied Research, Department for Microbiology and Biotechnology, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Sergey S. Zaitsev
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Anna M. Lyapina
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Natalya V. Kichemazova
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Yury V. Saltykov
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Mariya A. Khizhnyakova
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| | - Vitaliy V. Evstifeev
- Laboratory of Viral and Chlamydial Infections, Federal Center for Toxicological, Radiation and Biological Safety, Kazan, Russia
- Department of Microbiology, Virology and Immunology, Kazan State Academy of Veterinary Medicine by N.E. Bauman, Kazan City, Russia
| | - Olga S. Larionova
- Laboratory for Fundamental and Applied Research, Department for Microbiology and Biotechnology, Saratov State University of Genetics, Biotechnology and Engineering Named After N.I. Vavilov, Saratov, Russia
| |
Collapse
|
2
|
Nie MZ, Zhang RQ, Zhao MC, Tan H, Hu YX, Fan GH, Li JY, He AN, Tian FY, Li FY, Zheng YH, Shen XX, Tie YQ, Ma XJ. Development of a duplex recombinase-aided amplification assay for direct detection of Mycoplasma pneumoniae and Chlamydia trachomatis in clinical samples. METHODS IN MICROBIOLOGY 2022; 198:106504. [PMID: 35654228 DOI: 10.1016/j.mimet.2022.106504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Pneumonia caused by Mycoplasma pneumoniae is common in the elderly and children, and pneumonia caused by Chlamydia trachomatis is prevalent in newborns. This study aimed to establish a rapid, sensitive, and simple method for the direct detection of M. pneumoniae and C. trachomatis in clinical samples without DNA extraction. METHODS We established a duplex recombinase-aided amplification (RAA) assay with the RNAseP gene as an internal control for detecting the P1 gene of M. pneumoniae and the ORF8 gene of C. trachomatis, respectively. The results were obtained at 39 °C within 15-20 min. A total of 130 clinical samples suspected of M. pneumoniae or C. trachomatis infection were collected and tested by duplex RAA and PCR. DNA extracted via a commercial kit or treated with a nucleic acid-releasing agent was used and compared, respectively. Standard recombinant plasmids were used to test the sensitivity of the duplex RAA assay. In addition, other similar common pathogens were used to verify the specificity of the duplex RAA assay. RESULTS The sensitivity of the duplex RAA assay for detecting M. pneumoniae and C. trachomatis was 10 copies/μL using recombinant plasmids. Compared with PCR, the sensitivity and specificity of duplex RAA assays for M. pneumoniae and C. trachomatis was 100% using clinical DNA samples extracted using a commercial kit and a nucleic acid-releasing agent, and the Kappa value was 1. CONCLUSION The advantages of this duplex RAA assay include high sensitivity and specificity, short duration, and simple extraction steps, with potential for use in the on-site detection of M. pneumoniae and C. trachomatis in resource-limited settings.
Collapse
Affiliation(s)
- Ming-Zhu Nie
- Hebei Medical University, Shijiazhuang 050031, Hebei, China; NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China.
| | - Rui-Qing Zhang
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China.
| | - Meng-Chuan Zhao
- Children's Hospital of Hebei Province, Shijiazhuang 050031, Hebei, China
| | - He Tan
- Hebei General Hospital, Shijiazhuang 050051, Hebei, China
| | - Ya-Xin Hu
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China; North China University of Science and Technology, Tangshan 063210, Hebei, China
| | - Guo-Hao Fan
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China
| | - Jing-Yi Li
- Hebei Medical University, Shijiazhuang 050031, Hebei, China; NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China
| | - An-Na He
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China; North China University of Science and Technology, Tangshan 063210, Hebei, China
| | - Feng-Yu Tian
- Hebei Medical University, Shijiazhuang 050031, Hebei, China; NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China
| | - Feng-Yu Li
- Hebei Medical University, Shijiazhuang 050031, Hebei, China; NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China
| | - Ye-Huan Zheng
- Autobio Diagnostics CO., Ltd, Zhengzhou 450000, Henan, China
| | - Xin-Xin Shen
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China.
| | - Yan-Qing Tie
- Hebei General Hospital, Shijiazhuang 050051, Hebei, China.
| | - Xue-Jun Ma
- NHC Key Laboratory of Medical Virology and Viral Diseases, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, No. 155, Changbai Street, Changping District, Beijing 102206, China.
| |
Collapse
|
3
|
A Chlamydial Plasmid-Dependent Secretion System for the Delivery of Virulence Factors to the Host Cytosol. mBio 2021; 12:e0117921. [PMID: 34101486 PMCID: PMC8262877 DOI: 10.1128/mbio.01179-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Chlamydia are obligate intracellular Gram-negative bacteria distinguished by a unique developmental biology confined within a parasitophorous vacuole termed an inclusion. The chlamydial plasmid is a central virulence factor in the pathogenesis of infection. Plasmid gene protein 4 (Pgp4) regulates the expression of plasmid gene protein 3 (Pgp3) and chromosomal glycogen synthase (GlgA), virulence factors secreted from the inclusion to the host cytosol by an unknown mechanism. Here, we identified a plasmid-dependent secretion system for the cytosolic delivery of Pgp3 and GlgA. The secretion system consisted of a segregated population of globular structures originating from midcycle reticulate bodies. Globular structures contained the Pgp4-regulated proteins CT143, CT144, and CT050 in addition to Pgp3 and GlgA. Genetic replacement of Pgp4 with Pgp3 or GlgA negated the formation of globular structures, resulting in retention of Pgp3 and GlgA in chlamydial organisms. The generation of globular structures and secretion of virulence factors occurred independently of type 2 and type 3 secretion systems. Globular structures were enriched with lipopolysaccharide but lacked detectable major outer membrane protein and heat shock protein 60, implicating them as outer membrane vesicles. Thus, we have discovered a novel chlamydial plasmid-dependent secretion system that transports virulence factor cargo from the chlamydial inclusion to the host cytosol.
Collapse
|
4
|
de la Maza LM, Darville TL, Pal S. Chlamydia trachomatis vaccines for genital infections: where are we and how far is there to go? Expert Rev Vaccines 2021; 20:421-435. [PMID: 33682583 DOI: 10.1080/14760584.2021.1899817] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world. Antibiotic treatment does not prevent against reinfection and a vaccine is not yet available. AREAS COVERED We focus the review on the progress made of our understanding of the immunological responses required for a vaccine to elicit protection, and on the antigens, adjuvants, routes of immunization and delivery systems that have been tested in animal models. PubMed and Google Scholar were used to search publication on these topics for the last 5 years and recent Reviews were examined. EXPERT OPINION The first Phase 1 clinical trial of a C. trachomatis vaccine to protect against genital infections was successfully completed. We expect that, in the next five years, additional vaccine clinical trials will be implemented.
Collapse
Affiliation(s)
- Luis M de la Maza
- Department of Pathology and Laboratory Medicine Medical Sciences, I, Room D440 University of California, Irvine, California, USA
| | - Toni L Darville
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sukumar Pal
- Department of Pathology and Laboratory Medicine Medical Sciences, I, Room D440 University of California, Irvine, California, USA
| |
Collapse
|
5
|
Chlamydia trachomatis intra-bacterial and total plasmid copy number in clinical urogenital samples. Sci Rep 2021; 11:259. [PMID: 33420252 PMCID: PMC7794532 DOI: 10.1038/s41598-020-80645-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 12/22/2020] [Indexed: 12/03/2022] Open
Abstract
Chlamydia trachomatis (CT) increases its plasmid numbers when stressed, as occurs in clinical trachoma samples. Most CT tests target the plasmid to increase the test sensitivity, but some only target the chromosome. We investigated clinical urogenital samples for total plasmid copy numbers to assess its diagnostic value and intra-bacterial plasmid copy numbers to assess its natural variation. Both plasmid and chromosome copies were quantified using qPCR, and the plasmid:chromosome ratio (PCr) calculated in two cohorts: (1) 383 urogenital samples for the total PCR (tPCr), and (2) 42 vaginal swabs, with one half treated with propium-monoazide (PMA) to prevent the quantification of extracellular DNA and the other half untreated to allow for both tPCr and intra-bacterial PCr (iPCr) quantification. Mann–Whitney U tests compared PCr between samples, in relation to age and gender. Cohort 1: tPCr varied greatly (1–677, median 16). Median tPCr was significantly higher in urines than vaginal swabs (32 vs. 11, p < 0.001). Cohort 2: iPCr was more stable than tPCr (range 0.1–3 vs. 1–11). To conclude, tPCr in urogenital samples was much more variable than previously described. Transport time and temperature influences DNA degradation, impacting chromosomal DNA more than plasmids and urine more than vaginal samples. Data supports a plasmid target in CT screening assays to increase clinical sensitivity.
Collapse
|
6
|
Neena A, Deepa R. Detection of chlamydia trachomatis infection among the pregnant women attending a tertiary care hospital in Kerala - South India by polymerase chain reaction. Indian J Med Microbiol 2020; 38:319-323. [PMID: 33154242 DOI: 10.4103/ijmm.ijmm_19_429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background Chlamydia trachomatis infection is the most prevalent bacterial sexually transmitted infection and may influence pregnancy outcome. Aims and Objectives This study was conducted to assess Chlamydial infection during pregnancy by PCR. Materials and Methods Study group consists of patients who are attending the antenatal clinics. Endocervical swabs were collected from 300 patients. Results Off the 300 samples tested, 29 were positive as per PCR which used CT F : 5' CGT GTC GGC AAT CCT GCT GAT 3' and CT R : 5' GTC GAT AAC ATA GTC ACG ATA GTC 3'as the primers. Conclusion This suggests there is a prevalence of Chlamydia trachomatis in our population which is 10%. Hence, it should be noted as a significant public health problem especially among sexually active young women of child bearing age. Timely detection and prompt treatment of Chlamydial infection during pregnancy can eliminate its adverse outcomes.
Collapse
Affiliation(s)
- A Neena
- Department of Microbiology, Azeezia Institute of Medical Sciences and Research, Kollam, Kerala, India
| | - R Deepa
- Department of Microbiology, SR Medical College and Research Foundation, Thiruvananthapuram, Kerala, India
| |
Collapse
|
7
|
Szabo KV, O’Neill CE, Clarke IN. Diversity in Chlamydial plasmids. PLoS One 2020; 15:e0233298. [PMID: 32469898 PMCID: PMC7259575 DOI: 10.1371/journal.pone.0233298] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/01/2020] [Indexed: 11/30/2022] Open
Abstract
Background Evolutionary studies have been conducted that have investigated the chromosomal variance in the genus of Chlamydia. However, no all-encompassing genus-wide comparison has been performed on the plasmid. Therefore, there is a gap in the current knowledge on Chlamydia plasmid diversity. Aims This project is aimed to investigate and establish the nature and extent of diversity across the entire genus of Chlamydia, by comparing the sequences of all currently available plasmid carrying strains. Methods The PUBMED database was used to identify plasmid sequences from all available strains that met the set quality criteria for their inclusion in the study. Alignments were performed on the 51 strains that fulfilled the criteria using MEGA X software. Following that Maximum Likelihood estimation was used to construct 11 phylogenetic trees of the whole plasmid sequence, the individual 8 coding sequences, the iteron and a chromosomal gene ompA as a comparator. Results The genus-wide plasmid phylogeny produced three distinct lineages labelled as alpha, beta and gamma. Nineteen genotypes were found in the initial whole plasmid analysis. Their distribution was allocated as six C. pecorum, two C. pneumoniae, one C. gallinacea, one C. avium, one C. caviae, one C. felis, two C. psittaci, one C. trachomatis, one C. muridarum, and two C. suis. The chromosomal comparative gene ompA supported this distribution, with the same number of primary clades with the same species distribution. However, ompA sequence comparison resulted in fewer genotypes due to a reduced amount of available sequences (33 out of 51). All results were statistically significant. Conclusion The results of this study indicate that the common bacterial ancestor of all the species had a plasmid, which has diverged over time. Moreover, it suggests that there is a strong evolutionary selection towards these species retaining their plasmids due to its high level of conservation across the genus, with the notable exception of C. pneumoniae. Furthermore, the evolutionary analysis showed that the plasmid and the chromosome have co-evolved.
Collapse
Affiliation(s)
- Kolos V. Szabo
- Faculty of Medicine, University of Southampton, Southampton, Hampshire, United Kingdom
- * E-mail:
| | - Colette E. O’Neill
- Molecular Microbiology Group, Clinical and Experimental Sciences, University Hospital Southampton, Southampton, Hampshire, United Kingdom
| | - Ian N. Clarke
- Molecular Microbiology Group, Clinical and Experimental Sciences, University Hospital Southampton, Southampton, Hampshire, United Kingdom
| |
Collapse
|
8
|
Immunization with Chlamydia psittaci plasmid-encoded protein CPSIT_p7 induces partial protective immunity against chlamydia lung infection in mice. Immunol Res 2018; 66:471-479. [DOI: 10.1007/s12026-018-9018-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
9
|
A simple and rapid DNA extraction method for Chlamydia trachomatis detection from urogenital swabs. Diagn Microbiol Infect Dis 2017; 89:182-184. [PMID: 28918068 DOI: 10.1016/j.diagmicrobio.2017.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/03/2017] [Accepted: 08/10/2017] [Indexed: 11/22/2022]
Abstract
A highly sensitive and specific Chlamydia trachomatis (CT) diagnostic test was developed by combining filtration isolation of nucleic acid (FINA) extraction with quantitative polymerase chain reaction including an internal control to identify test inhibition. A pilot study of 40 clinical specimens yielded 100% sensitivity and specificity.
Collapse
|
10
|
Update on Chlamydia trachomatis Vaccinology. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00543-16. [PMID: 28228394 DOI: 10.1128/cvi.00543-16] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Attempts to produce a vaccine to protect against Chlamydia trachomatis-induced trachoma were initiated more than 100 years ago and continued for several decades. Using whole organisms, protective responses were obtained. However, upon exposure to C. trachomatis, disease exacerbation developed in some immunized individuals, precluding the implementation of the vaccine. Evidence of the role of C. trachomatis as a sexually transmitted pathogen started to emerge in the 1960s, and it soon became evident that it can cause acute infections and long-term sequelae in women, men, and newborns. The main focus of this minireview is to summarize recent findings and discuss formulations, including antigens, adjuvants, routes, and delivery systems for immunization, primarily explored in the female mouse model, with the goal of implementing a vaccine against C. trachomatis genital infections.
Collapse
|
11
|
Advances and Obstacles in the Genetic Dissection of Chlamydial Virulence. Curr Top Microbiol Immunol 2017; 412:133-158. [PMID: 29090367 DOI: 10.1007/82_2017_76] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Obligate intracellular pathogens in the family Chlamydiaceae infect taxonomically diverse eukaryotes ranging from amoebae to mammals. However, many fundamental aspects of chlamydial cell biology and pathogenesis remain poorly understood. Genetic dissection of chlamydial biology has historically been hampered by a lack of genetic tools. Exploitation of the ability of chlamydia to recombine genomic material by lateral gene transfer (LGT) ushered in a new era in chlamydia research. With methods to map mutations in place, genetic screens were able to assign functions and phenotypes to specific chlamydial genes. Development of an approach for stable transformation of chlamydia also provided a mechanism for gene delivery and platforms for disrupting chromosomal genes. Here, we explore how these and other tools have been used to test hypotheses concerning the functions of known chlamydial virulence factors and discover the functions of completely uncharacterized genes. Refinement and extension of the existing genetic tools to additional Chlamydia spp. will substantially advance understanding of the biology and pathogenesis of this important group of pathogens.
Collapse
|
12
|
Brade H, Brabetz W, Brade L, Hoist O, Löbau S, Lucakova M, Mamat U, Rozalski A, Zych K, Kosma P. Review: Chlamydial lipopolysaccharide. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/096805199700400108] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- H. Brade
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - W. Brabetz
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - L. Brade
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - O. Hoist
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - S. Löbau
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - M. Lucakova
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - U. Mamat
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - A. Rozalski
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - K. Zych
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Borstel, Germany
| | - P. Kosma
- Institute of Chemistry, University of Agricultural Sciences, Vienna, Austria
| |
Collapse
|
13
|
Abstract
Chlamydia spp. are ubiquitous, obligate, intracellular Gram-negative bacterial pathogens that undergo a unique biphasic developmental cycle transitioning between the infectious, extracellular elementary body and the replicative, intracellular reticulate body. The primary Chlamydia species associated with human disease are C. trachomatis, which is the leading cause of both reportable bacterial sexually transmitted infections and preventable blindness, and C. pneumoniae, which infects the respiratory tract and is associated with cardiovascular disease. Collectively, these pathogens are a significant source of morbidity and pose a substantial financial burden on the global economy. Past efforts to elucidate virulence mechanisms of these unique and important pathogens were largely hindered by an absence of genetic methods. Watershed studies in 2011 and 2012 demonstrated that forward and reverse genetic approaches were feasible with Chlamydia and that shuttle vectors could be selected and maintained within the bacterium. While these breakthroughs have led to a steady expansion of the chlamydial genetic tool kit, there are still roads left to be traveled. This minireview provides a synopsis of the currently available genetic methods for Chlamydia along with a comparison to the methods used in other obligate intracellular bacteria. Limitations and advantages of these techniques will be discussed with an eye toward the methods still needed, and how the current state of the art for genetics in obligate intracellular bacteria could direct future technological advances for Chlamydia.
Collapse
|
14
|
Abou Tayoun AN, Burchard PR, Caliendo AM, Scherer A, Tsongalis GJ. A multiplex PCR assay for the simultaneous detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. Exp Mol Pathol 2015; 98:214-8. [PMID: 25595915 DOI: 10.1016/j.yexmp.2015.01.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/12/2015] [Indexed: 11/17/2022]
Abstract
INTRODUCTION For developing countries, sexually transmitted infections (STIs) and their complications are ranked in the top 5 disease categories for which adults seek medical treatment. Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) are the three most common STIs worldwide, with TV accounting for over half of the cases. In developing countries, traditional methods for diagnosing STIs are laborious, often not very sensitive, and have a long turnaround time with most recent commercially available diagnostic tests targeting one or, at most, two of these STIs at a time. Here, we describe the development of a highly sensitive, rapid and affordable sample-to-answer multiplex PCR-based assay for the simultaneous detection of Trichomonas vaginalis, Neisseria gonorrhoeae, and Chlamydia trachomatis. MATERIALS AND METHODS We designed a multiplex PCR assay for the detection of 4 targets (CT, TV, NG, and process/PCR control) using melt curve analysis. To establish the limit of detection (LOD) for each pathogen, we used previously extracted and quantified TV, NG, and CT genomic DNA (Vircell, Spain). For each target, the LOD was determined by lowering its copy number while increasing the other two STI loads in a stepwise fashion. The process/PCR control remained constant in the optimized assay and was spiked into each sample before extraction. For a concordance study, we tested urine, vaginal and rectal swab specimens from 26 patients positive for one or more of the tested STIs. In addition, 56 liquid cytology specimens (Thinprep) were used to assess specificity. RESULTS This assay has a turnaround time of less than 2h and has a limit of detection as low as 7-31 copies for each STI in the presence of the other 2 targets. Our assay also demonstrated 100% concordance with 26 known clinical samples from urine, vaginal and rectal swab specimens. TV, NG, CT, and our process/PCR control were consistently identified at 78°C, 82.3°C, 85.7°C, and ~92°C, respectively. When applied to DNA extracted from residual Thinprep specimens, the assay was negative in 54/56 samples. Two samples were found to be co-infected with CT. CONCLUSIONS Our multiplex assay combines a rapid and cost-effective approach to molecular diagnostics with the versatility required for use within a variety of laboratory settings. These performance characteristics make this multiplex STI assay highly suitable for use in a clinical laboratory.
Collapse
Affiliation(s)
- Ahmad N Abou Tayoun
- Department of Pathology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States; Dartmouth Hitchcock Medical Center and Norris Cotton Cancer Center, Lebanon, NH, United States
| | - Paul R Burchard
- Department of Pathology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States; Dartmouth Hitchcock Medical Center and Norris Cotton Cancer Center, Lebanon, NH, United States
| | - Angela M Caliendo
- Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Axel Scherer
- Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Gregory J Tsongalis
- Department of Pathology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States; Dartmouth Hitchcock Medical Center and Norris Cotton Cancer Center, Lebanon, NH, United States.
| |
Collapse
|
15
|
Zhang K, Huo H, Sun Y, Wang L, Zhang R, Lin G, Xie J, Wang Q, Li J. Application of HTB-SiHa cells transfected with a recombinant plasmid for external quality assessment of Chlamydia trachomatis PCR. Ann Lab Med 2014; 34:360-6. [PMID: 25187888 PMCID: PMC4151004 DOI: 10.3343/alm.2014.34.5.360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/11/2014] [Accepted: 06/24/2014] [Indexed: 01/29/2023] Open
Abstract
Background The participation of laboratories in external quality assessment (EQA) programs is required for the quality assurance of nucleic acid amplification of Chlamydia trachomatis. This study aimed to construct a new quality control (QC) material applicated in EQA of C. trachomatis PCR. Methods A QC material-HTB-SiHa cells transfected with a recombinant plasmid containing the cryptic plasmid sequence-was constructed for C. trachomatis PCR detection, and four different panels, each consisting of 4 positive samples with serial dilution of the constructed QC material and 1 negative sample, were distributed by the National Center for Clinical Laboratories among four groups of 275, 268, 317, and 304 participants across China from 2011 through 2012. A total of eight commercial kits were used for C. trachomatis PCR detection in participants. Results Nine laboratories reported false-positive results (0.9%). As the series dilution increased, the correct reporting of the data sets decreased; the lowest correct rate was 96.3% in the weakest positive samples (104 copies/mL). Eight laboratories reported false-positive results, and 42 laboratories reported false-negative results in the EQA detection of C. trachomatis. No significant differences were observed in the detection of the constructed C. trachomatis positive samples (97.9%, 98.5%, 100%, 98.5%; P=0.36) and negative samples (100%, 99.0%, 100%, 99.0%; P=0.764) using four commercial kits commonly used in China. Conclusions The results of the EQA study indicated that the constructed material provides a noninfectious, stable control material with sufficient volume for PCR detection of C. trachomatis.
Collapse
Affiliation(s)
- Kuo Zhang
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Hong Huo
- Department of Clinical Laboratory, Beijing Chaoyang Hospital Affiliated to the Capital University of Medical Sciences, Beijing, China
| | - Yu Sun
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Lunan Wang
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Rui Zhang
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Guigao Lin
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Jiehong Xie
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| | - Qingtao Wang
- Department of Clinical Laboratory, Beijing Chaoyang Hospital Affiliated to the Capital University of Medical Sciences, Beijing, China
| | - Jinming Li
- National Center for Clinical Laboratories, Beijing Hospital, Beijing, China
| |
Collapse
|
16
|
Plasmid CDS5 influences infectivity and virulence in a mouse model of Chlamydia trachomatis urogenital infection. Infect Immun 2014; 82:3341-9. [PMID: 24866804 DOI: 10.1128/iai.01795-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The native plasmid of both Chlamydia muridarum and Chlamydia trachomatis has been shown to control virulence and infectivity in mice and in lower primates. We recently described the development of a plasmid-based genetic transformation protocol for Chlamydia trachomatis that for the first time provides a platform for the molecular dissection of the function of the chlamydial plasmid and its individual genes or coding sequences (CDS). In the present study, we transformed a plasmid-free lymphogranuloma venereum isolate of C. trachomatis, serovar L2, with either the original shuttle vector (pGFP::SW2) or a derivative of pGFP::SW2 carrying a deletion of the plasmid CDS5 gene (pCDS5KO). Female mice were inoculated with these strains either intravaginally or transcervically. We found that transformation of the plasmid-free isolate with the intact pGFP::SW2 vector significantly enhanced infectivity and induction of host inflammatory responses compared to the plasmid-free parental isolate. Transformation with pCDS5KO resulted in infection courses and inflammatory responses not significantly different from those observed in mice infected with the plasmid-free isolate. These results indicate a critical role of plasmid CDS5 in in vivo fitness and in induction of inflammatory responses. To our knowledge, these are the first in vivo observations ascribing infectivity and virulence to a specific plasmid gene.
Collapse
|
17
|
Sturdevant GL, Zhou B, Carlson JH, Whitmire WM, Song L, Caldwell HD. Infectivity of urogenital Chlamydia trachomatis plasmid-deficient, CT135-null, and double-deficient strains in female mice. Pathog Dis 2014; 71:90-2. [PMID: 24376189 DOI: 10.1111/2049-632x.12121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/04/2013] [Accepted: 12/12/2013] [Indexed: 11/28/2022] Open
Abstract
Chlamydia trachomatis is the most common cause of human bacterial sexually transmitted infections and is the world's leading cause of infectious preventable blindness. The chlamydial 7.5-kb plasmid and chromosomal gene CT135 have been shown to be important virulence factors in both nonhuman primate and mouse infection models. Chlamydia trachomatis plasmid-deficient urogenital isolates and a predicted CT135 null mutant have been evaluated independently in the female mouse genital tract model and both have been shown to reduce infectivity and virulence. However, these attenuating phenotypes have not been evaluated collectively in the murine model. Here, we test the infectivity of C. trachomatis serovar D strains in the mouse model that are plasmid-deficient, CT135 disrupted, or possess a combination of these attenuating genotypes. We find that the presence of the plasmid results in infections with higher infectious burdens, whereas CT135 facilitates a more protracted or chronic infection. Not unexpectedly, a combination of these genetic deficiencies resulted in a strain with enhanced infection attenuation characteristics.
Collapse
Affiliation(s)
- Gail L Sturdevant
- Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | | | | | | | | | | |
Collapse
|
18
|
Reduced live organism recovery and lack of hydrosalpinx in mice infected with plasmid-free Chlamydia muridarum. Infect Immun 2013; 82:983-92. [PMID: 24343644 DOI: 10.1128/iai.01543-13] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Plasmid-free Chlamydia trachomatis and Chlamydia muridarum fail to induce severe pathology. To evaluate whether the attenuated pathogenicity is due to insufficient infection or inability of the plasmidless chlamydial organisms to trigger pathological responses, we compared plasmid-competent and plasmid-free C. muridarum infections in 5 different strains of mice. All 5 strains developed hydrosalpinx following intravaginal inoculation with plasmid-competent, but not inoculation with plasmid-free, C. muridarum. The lack of hydrosalpinx induction by plasmid-free C. muridarum correlated with significantly reduced live organism recovery from the lower genital tract and shortened infection in the upper genital tract. The plasmid-free C. muridarum organisms failed to induce hydrosalpinx even when the organisms were directly inoculated into the oviduct via an intrabursal injection, which was accompanied by significantly reduced survival of the plasmidless organisms in the genital tracts. Furthermore, plasmid-competent C. muridarum organisms after UV inactivation were no longer able to induce hydrosalpinx even when directly delivered into the oviduct at a high dose. Together, these observations suggest that decreased survival of and shortened infection with plasmid-free C. muridarum may contribute significantly to its attenuated pathogenicity. We conclude that adequate live chlamydial infection in the oviduct may be necessary to induce hydrosalpinx.
Collapse
|
19
|
Plasmid copy number and disease severity in naturally occurring ocular Chlamydia trachomatis infection. J Clin Microbiol 2013; 52:324-7. [PMID: 24197878 PMCID: PMC3911420 DOI: 10.1128/jcm.02618-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Chlamydia trachomatis plasmid is a virulence factor. Plasmid copy number, C. trachomatis load and disease severity were assessed in a treatment-naive population where trachoma is hyperendemic. By using droplet digital PCR, plasmid copy number was found to be stable (median, 5.34 [range, 1 to 18]) and there were no associations with C. trachomatis load or disease severity.
Collapse
|
20
|
Kannan RM, Gérard HC, Mishra MK, Mao G, Wang S, Hali M, Whittum-Hudson JA, Hudson AP. Dendrimer-enabled transformation of Chlamydia trachomatis. Microb Pathog 2013; 65:29-35. [PMID: 24075820 DOI: 10.1016/j.micpath.2013.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 08/23/2013] [Accepted: 08/30/2013] [Indexed: 10/26/2022]
Abstract
Lack of a system for genetic manipulation of Chlamydia trachomatis has been a key challenge to advancing understanding the molecular genetic basis of virulence for this bacterial pathogen. We developed a non-viral, dendrimer-enabled system for transformation of this organism and used it to characterize the effects of inserting the common 7.5 kbp chlamydial plasmid into strain L2(25667R), a C. trachomatis isolate lacking it. The plasmid was cloned in pUC19 and the clone complexed to polyamidoamine dendrimers, producing ∼83 nm spherical particles. Nearly confluent McCoy cell cultures were infected with L2(25667R) and reference strain L2(434). At 16 h post-infection, medium was replaced with dendrimer-plasmid complexes in medium lacking additives (L2(25667R)) or with additive-free medium alone (L2(434)). Three h later complexes/buffer were removed, and medium was replaced; cultures were harvested at various times post-transformation for analyses. Real time PCR and RT-PCR of nucleic acids from transformed cultures demonstrated plasmid replication and gene expression. A previous report indicated that one or more plasmid-encoded product govern(s) transcription of the glycogen synthase gene (glgA) in standard strains. In L2(25667R) the gene is not expressed, but transformants of that strain given the cloned chlamydial plasmid increase glgA expression, as does L2(434). The cloned plasmid is retained, replicated, and expressed in transformants over at least 5 passages, and GFP is expressed when transformed into growing L2(25667R). This transformation system will allow study of chlamydial gene function in pathogenesis.
Collapse
Affiliation(s)
- Rangaramanujam M Kannan
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21235, USA
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Ferreira R, Borges V, Nunes A, Borrego MJ, Gomes JP. Assessment of the load and transcriptional dynamics of Chlamydia trachomatis plasmid according to strains' tissue tropism. Microbiol Res 2013; 168:333-339. [PMID: 23590987 DOI: 10.1016/j.micres.2013.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/28/2013] [Accepted: 02/06/2013] [Indexed: 10/27/2022]
Abstract
Chlamydia trachomatis maintain a conserved plasmid, which is a primary regulator of chromosomal genes, but there is no experimental evidences associating it with the strains' differential tissue tropism (ocular and genital mucosae, and lymph nodes). We investigated if the number of plasmids per strain correlate with expression profiles of plasmid ORFs and small anti-sense RNAs (sRNAs), and also if these molecular features underlie tropism dissimilarities. We performed absolute and relative qPCR to determine both the plasmid load and expression throughout C. trachomatis development. Our findings suggest that plasmid load (never exceeding 8 copies) is not a function of expression needs and does not reflect tissue tropism. However, for most ORFs, ocular strains presented lower expression than genital or lymphogranuloma venereum (LGV) strains, and ORF6/pgp4 (transcriptional regulator of virulence associated genes) presented the highest mean expression among strains, followed by the virulence factor ORF5/pgp3 (also regulated by ORF6/pgp4). More, the mean expression levels of the sRNA-2 (anti-sense to ORF2/pgp8) were up to 100-fold higher than those of the ORFs, and up to 12-fold higher than that of sRNA-7 (anti-sense to ORF7/pgp5) for the LGV strains. Overall, besides the known regulatory role of C. trachomatis plasmid, its transcriptional dynamics sustains tropism differences.
Collapse
Affiliation(s)
- Rita Ferreira
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - Vítor Borges
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - Alexandra Nunes
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - Maria José Borrego
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal
| | - João Paulo Gomes
- Department of Infectious Diseases, National Institute of Health, Av. Padre Cruz, 1649-016 Lisbon, Portugal.
| |
Collapse
|
22
|
Keenan JD, See CW, Moncada J, Ayele B, Gebre T, Stoller NE, McCulloch CE, Porco TC, Gaynor BD, Emerson PM, Schachter J, Lietman TM. Diagnostic characteristics of tests for ocular Chlamydia after mass azithromycin distributions. Invest Ophthalmol Vis Sci 2012; 53:235-40. [PMID: 22159017 DOI: 10.1167/iovs.11-8493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Although trachoma control programs frequently use the World Health Organization (WHO) simplified grading system for trachoma to monitor the clinical response after repeated mass azithromycin treatments, the programmatic relevance of this evaluation after multiple rounds of antibiotic treatments is unclear. METHODS Three rounds of annual mass azithromycin were distributed to 12 villages in Ethiopia. Twelve months after the third treatment, children were assessed for follicular trachomatous inflammation (TF) and intense trachomatous inflammation (TI) using the WHO simplified grading system and for ocular chlamydial infection using DNA-based and RNA-based tests. Test characteristics for predicting chlamydial infection were computed assuming a chlamydial RNA-based gold standard. As a secondary analysis, test characteristics were also assessed using a latent class analysis. RESULTS The prevalence of RNA evidence of ocular chlamydia was 7.1% (95% confidence interval [CI], 2.7-17.4). A DNA-based test and TF had sensitivities of 61.0% (95% CI, 47.1-73.3) and 65.9% (95% CI, 41.6-83.9), specificities of 100% (95% CI, 99.3-100) and 67.5% (95% CI, 61.0-73.5), and positive predictive values of 100% (95% CI, 86.3-100) and 13.4% (95% CI, 5.5-29.3) compared with an RNA-based gold standard. The latent class analysis confirmed that the RNA-based test was a reasonable choice for a gold standard, with a sensitivity of 100% (95% CI, 67.1-100) and specificity of 99.6% (95% CI, 98.1-100). CONCLUSIONS Basing treatment decisions after mass azithromycin distributions on the WHO simplified grading system will maximize the treatment of infected persons compared with a DNA-based test but will also result in more uninfected persons being treated. The RNA-based test was considerably more sensitive, and almost equivalently specific, compared with a DNA-based test. (ClinicalTrials.gov number, NCT00322972.).
Collapse
Affiliation(s)
- Jeremy D Keenan
- F. I. Proctor Foundation, 513 Parnassus Avenue, Med Sci S309, Box 0412, University of California, San Francisco, San Francisco, CA 94143-0412, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
O'Neil D, Doseeva V, Rothmann T, Wolff J, Nazarenko I. Evaluation of Chlamydia trachomatis and Neisseria gonorrhoeae detection in urine, endocervical, and vaginal specimens by a multiplexed isothermal thermophilic helicase-dependent amplification (tHDA) assay. J Clin Microbiol 2011; 49:4121-5. [PMID: 21956990 PMCID: PMC3232959 DOI: 10.1128/jcm.00952-11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 09/16/2011] [Indexed: 11/20/2022] Open
Abstract
We have developed a new research assay that combines sequence-specific sample preparation and isothermal amplification for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae infections. The assay targets both the omp gene and the cryptic plasmid of C. trachomatis and the multicopy opa gene of N. gonorrhoeae, which are amplified and detected in a single reaction. We evaluated the ability of the assay to detect C. trachomatis and N. gonorrhoeae infections in first-catch urine, swab, and liquid-based cytology samples. Total agreement between the new assay and APTIMA Combo 2 varied between 95.3% and 100%, depending on the sample type and target detected. Total agreement between the new assay and BD ProbeTec varied between 96.7% and 100%, depending on the sample type and target detected. The assay has a simple work flow, and endpoint results can be achieved in 3 h, including sample preparation. The assay described here was evaluated for research use and was compared to commercially available assays.
Collapse
|
24
|
|
25
|
Kari L, Whitmire WM, Olivares-Zavaleta N, Goheen MM, Taylor LD, Carlson JH, Sturdevant GL, Lu C, Bakios LE, Randall LB, Parnell MJ, Zhong G, Caldwell HD. A live-attenuated chlamydial vaccine protects against trachoma in nonhuman primates. ACTA ACUST UNITED AC 2011; 208:2217-23. [PMID: 21987657 PMCID: PMC3201208 DOI: 10.1084/jem.20111266] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In cynomolgus macaques, ocular infection with a live trachoma strain lacking the conserved 7.5-kb plasmid induced no ocular pathology but facilitated solid or partial protection from subsequent infection with a virulent strain of trachoma. Blinding trachoma is an ancient neglected tropical disease caused by Chlamydia trachomatis for which a vaccine is needed. We describe a live-attenuated vaccine that is safe and efficacious in preventing trachoma in nonhuman primates, a model with excellent predictive value for humans. Cynomolgus macaques infected ocularly with a trachoma strain deficient for the 7.5-kb conserved plasmid presented with short-lived infections that resolved spontaneously without ocular pathology. Multiple infections with the attenuated plasmid-deficient strain produced no inflammatory ocular pathology but induced an anti-chlamydial immune response. Macaques vaccinated with the attenuated strain were either solidly or partially protected after challenge with virulent plasmid-bearing organisms. Partially protected macaques shed markedly less infectious organisms than controls. Immune correlates of protective immunity were not identified, but we did detect a correlation between MHC class II alleles and solid versus partial protection. Epidemiological models of trachoma control indicate that a vaccine with this degree of efficacy would significantly reduce the prevalence of infection and rates of reinfection, known risk factors which drive blinding disease.
Collapse
Affiliation(s)
- Laszlo Kari
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
First report of performance of the Versant CT/GC DNA 1.0 assay (kPCR) for detection of Chlamydia trachomatis and Neisseria gonorrhoeae. J Clin Microbiol 2011; 49:1347-53. [PMID: 21307209 DOI: 10.1128/jcm.01634-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the analytical, work flow, and clinical performance of the Versant CT/GC DNA 1.0 assay (Versant CT/GC assay, where "CT" represents Chlamydia trachomatis and "GC" represents Neisseria gonorrhoeae). The assay simultaneously detects Chlamydia trachomatis and Neisseria gonorrhoeae in swab and first-catch urine (FCU) specimens. The limit of detection (LoD) was determined to be 342 copies/ml for C. trachomatis and 137 copies/ml for GC. The Versant CT/GC assay detected 15 C. trachomatis serovars and 46 GC strains. The Versant CT/GC assay demonstrated no cross-reactivity with 136 potentially cross-reacting organisms. Clinical concordance of the Versant CT/GC assay to the Aptima Combo 2 (AC2) assay from Gen-Probe was demonstrated using 1,129 patient specimens, including 589 urine and 540 swab specimens. Discrepant specimens were subjected to DNA sequencing to identify the presence of amplified targets and to identify false-positive and false-negative results. Overall percent agreement was greater than 98%. Positive and negative percent agreements for detection of C. trachomatis were 94.4% and 99.1%, respectively, in urine specimens and 95.8% and 99.8%, respectively, in swab specimens. Positive percent agreement for the detection of N. gonorrhoeae was 100% in both urine and swab specimens, and negative percent agreements were 99.6% and 99% in urine and swab specimens, respectively. In conclusion, the performance of the Versant CT/GC assay was comparable to that of the AC2 assay. The Versant CT/GC assay can be recommended for the detection of C. trachomatis and N. gonorrhoeae in swab and urine specimens of symptomatic and asymptomatic individuals.
Collapse
|
27
|
Lehmusvuori A, Juntunen E, Tapio AH, Rantakokko-Jalava K, Soukka T, Lövgren T. Rapid homogeneous PCR assay for the detection of Chlamydia trachomatis in urine samples. J Microbiol Methods 2010; 83:302-6. [PMID: 20888867 DOI: 10.1016/j.mimet.2010.09.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 09/21/2010] [Accepted: 09/24/2010] [Indexed: 11/15/2022]
Abstract
Chlamydia trachomatis infection is the most common bacterial sexually transmitted disease and a major public health problem worldwide. Fast and sensitive point-of-care diagnostics including non-invasive sample collection would be of value for the prevention of C. trachomatis transmission. The aim of this study was to develop a fast, reliable, non-invasive and easy-to-use homogenous PCR assay for the detection of C. trachomatis. Bacteria were concentrated from urine by a simple and fast centrifugation-based urine pretreatment method. Novel automated GenomEra technology was utilized for the rapid closed-tube PCR including time-resolved fluorometric detection of the target using lanthanide chelate labeled probes. We have developed a rapid C. trachomatis assay which provides qualitative results in 1 h with diagnostic sensitivity and specificity of 98.7% and 97.3%, respectively. The novel assay can be performed with minimal laboratory expertise and without sophisticated DNA-extraction devices and has performance comparable to current gold standard assays.
Collapse
Affiliation(s)
- Ari Lehmusvuori
- Department of Biotechnology, University of Turku, Tykistökatu 6A, 20520 Turku, Finland.
| | | | | | | | | | | |
Collapse
|
28
|
Patel AL, Sachdev D, Nagpal P, Chaudhry U, Sonkar SC, Mendiratta SL, Saluja D. Prevalence of Chlamydia infection among women visiting a gynaecology outpatient department: evaluation of an in-house PCR assay for detection of Chlamydia trachomatis. Ann Clin Microbiol Antimicrob 2010; 9:24. [PMID: 20822551 PMCID: PMC2944303 DOI: 10.1186/1476-0711-9-24] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/08/2010] [Indexed: 12/17/2022] Open
Abstract
Background Screening women for Chlamydia trachomatis infection in developing countries is highly desirable because of asymptomatic infection. The existing diagnostic methods in developing countries are not effective and their sensitivity fall below 45.0% which leads to further spread of infection. There is an urgent need for improved and cost effective diagnostic tests that will reduce the burden of sexually transmitted infections in the developing world. Methods Prevalence of C. trachomatis infection among women visiting gynaecology department of Hindu Rao hospital in Delhi, India was determined using Roche Amplicor Multi Well Plate kit (MWP) as well as using in-house PCR assay. We used 593 endocervical swabs for clinical evaluation of the in-house developed assay against Direct Fluorescence Assay (DFA; Group I n = 274) and Roche Amplicor MWP kit (Group II, n = 319 samples) and determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of the in-house developed assay. Results We detected 23.0% positive cases and there was a higher representation of women aged 18-33 in this group. An in-house PCR assay was developed and evaluated by targeting unique sequence within the gyrA gene of C. trachomatis. Specificity of the reaction was confirmed by using genomic DNA of human and other STI related microorganisms as template. Assay is highly sensitive and can detect as low as 10 fg of C. trachomatis DNA. The resolved sensitivity of in-house PCR was 94.5% compared with 88.0% of DFA assay. The high specificity (98.4%) and sensitivity (97.1%) of the in-house assay against Roche kit and availability of test results within 3 hours allowed for immediate treatment and reduced the risk of potential onward transmission. Conclusions The in-house PCR method is cost effective (~ 20.0% of Roche assay) and hence could be a better alternative for routine diagnosis of genital infection by C. trachomatis to facilitate improved screening and treatment management.
Collapse
Affiliation(s)
- Achchhe L Patel
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
| | | | | | | | | | | | | |
Collapse
|
29
|
Harley R, Day S, Di Rocco C, Helps C. The Chlamydophila felis plasmid is highly conserved. Vet Microbiol 2010; 146:172-4. [PMID: 20537821 DOI: 10.1016/j.vetmic.2010.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/27/2010] [Accepted: 05/03/2010] [Indexed: 10/19/2022]
Abstract
The presence of a plasmid in the Chlamydiaceae is both species and strain specific. Knowledge of the prevalence of the plasmid in different Chlamydia species is important for future studies aiming to investigate the role of the plasmid in chlamydial biology and disease. Although strains of Chlamydophila felis with or without the plasmid have been identified, only a small number of laboratory-adapted strains have been analysed and the prevalence of the plasmid in field isolates has not been determined. This study aimed to determine the prevalence of the plasmid in C. felis-positive conjunctival and oropharyngeal clinical samples submitted for routine diagnosis of C. felis by real-time (Q)PCR. DNA extracts from four laboratory-adapted strains were also analysed. QPCR assays targeting regions of C. felis plasmid genes pCF01, pCF02 and pCF03 were developed for the detection of plasmid DNA. QPCR analysis of DNA extracts from C. felis-positive clinical samples found evidence of plasmid DNA in 591 of 595 samples representing 561 of 564 (99.5%) clinical cases. Plasmid DNA was also detected by QPCR in laboratory-adapted strains 1497V, K2487 and K2490, but not strain 905. We conclude that the plasmid is highly conserved in C. felis, and plasmid-deficient strains represent a rare but important population for future studies of chlamydial plasmid function.
Collapse
Affiliation(s)
- Ross Harley
- University of Bristol, School of Clinical Veterinary Science, Langford House, Langford, Bristol BS40 5DU, United Kingdom.
| | | | | | | |
Collapse
|
30
|
Saikku PAI. Chlamydia. Infect Dis (Lond) 2010. [DOI: 10.1016/b978-0-323-04579-7.00177-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
31
|
Mohamad KY, Rodolakis A. Recent advances in the understanding of Chlamydophila pecorum infections, sixteen years after it was named as the fourth species of the Chlamydiaceae family. Vet Res 2009; 41:27. [PMID: 19995513 PMCID: PMC2820232 DOI: 10.1051/vetres/2009075] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 12/08/2009] [Indexed: 12/26/2022] Open
Abstract
Chlamydophila pecorum found in the intestine and vaginal mucus of asymptomatic ruminants has also been associated with different pathological conditions in ruminants, swine and koalas. Some endangered species such as water buffalos and bandicoots have also been found to be infected by C. pecorum. The persistence of C. pecorum strains in the intestine and vaginal mucus of ruminants could cause long-term sub-clinical infection affecting the animal’s health. C. pecorum strains present many genetic and antigenic variations, but coding tandem repeats have recently been found in some C. pecorum genes, allowing C. pecorum strains isolated from sick animals to be differentiated from those isolated from asymptomatic animals. This review provides an update on C. pecorum infections in different animal hosts and the implications for animal health. The taxonomy, typing and genetic aspects of C. pecorum are also reviewed.
Collapse
Affiliation(s)
- Khalil Yousef Mohamad
- Institut National de la Recherche Agronomique (INRA), UR1282, Infectiologie Animale et Santé Publique, F-37380 Nouzilly (Tours), France
| | | |
Collapse
|
32
|
Albrecht M, Sharma CM, Reinhardt R, Vogel J, Rudel T. Deep sequencing-based discovery of the Chlamydia trachomatis transcriptome. Nucleic Acids Res 2009; 38:868-77. [PMID: 19923228 PMCID: PMC2817459 DOI: 10.1093/nar/gkp1032] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogenic bacterium that has been refractory to genetic manipulations. Although the genomes of several strains have been sequenced, very little information is available on the gene structure of these bacteria. We used deep sequencing to define the transcriptome of purified elementary bodies (EB) and reticulate bodies (RB) of C. trachomatis L2b, respectively. Using an RNA-seq approach, we have mapped 363 transcriptional start sites (TSS) of annotated genes. Semi-quantitative analysis of mapped cDNA reads revealed differences in the RNA levels of 84 genes isolated from EB and RB, respectively. We have identified and in part confirmed 42 genome- and 1 plasmid-derived novel non-coding RNAs. The genome encoded non-coding RNA, ctrR0332 was one of the most abundantly and differentially expressed RNA in EB and RB, implying an important role in the developmental cycle of C. trachomatis. The detailed map of TSS in a thus far unprecedented resolution as a complement to the genome sequence will help to understand the organization, control and function of genes of this important pathogen.
Collapse
Affiliation(s)
- Marco Albrecht
- University of Würzburg, Biocentre, Department of Microbiology, Am Hubland, D-97074 Würzburg, Germany
| | | | | | | | | |
Collapse
|
33
|
Sachdeva P, Patel AL, Sachdev D, Ali M, Mittal A, Saluja D. Comparison of an in-house PCR assay, direct fluorescence assay and the Roche AMPLICOR Chlamydia trachomatis kit for detection of C. trachomatis. J Med Microbiol 2009; 58:867-873. [PMID: 19502371 DOI: 10.1099/jmm.0.008698-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To improve the control of Chlamydia trachomatis infection in India, a rapid, specific and cost-effective method is much needed. We developed an in-house PCR assay by targeting a unique genomic sequence encoding a protein from the C. trachomatis phospholipase D endonuclease superfamily that produces an amplified fragment of 368 bp. The specificity of the primers was confirmed using genomic DNA from other sexually transmitted disease-causing and related micro-organisms and from humans. The assay was highly sensitive and could detect as low as 10 fg C. trachomatis DNA. Clinical evaluation of the in-house-developed PCR was carried out using 450 endocervical specimens that were divided in two groups. In group I (n=274), in-house PCR was evaluated against the direct fluorescence assay. The resolved sensitivity of the in-house PCR method was 97.22 % compared with 88 % for the direct fluorescent antibody assay. In group II (n=176), the in-house PCR was compared with the commercial Roche AMPLICOR MWP CT detection kit. The resolved sensitivity of the in-house PCR assay reported here was 93.1 % and the specificity was 97.46 %, making it a cost-effective alternative for routine diagnosis of genital infection by C. trachomatis. The method should facilitate early detection leading to better prevention and treatment of genital infection in India.
Collapse
Affiliation(s)
- Poonam Sachdeva
- Dr B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Achchhe Lal Patel
- Dr B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Divya Sachdev
- Dr B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Mashook Ali
- Dr B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Aruna Mittal
- Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India
| | - Daman Saluja
- Dr B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| |
Collapse
|
34
|
Wooters MA, Kaufhold RM, Field JA, Indrawati L, Heinrichs JH, Smith JG. A real-time quantitative polymerase chain reaction assay for the detection of Chlamydia in the mouse genital tract model. Diagn Microbiol Infect Dis 2008; 63:140-7. [PMID: 19026505 DOI: 10.1016/j.diagmicrobio.2008.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 10/11/2008] [Indexed: 11/18/2022]
Abstract
Chlamydia trachomatis is a human pathogen that infects genital tracts in women. Disease control may be achieved through development of an efficacious vaccine. A mouse genital tract model serves as a tool for evaluation of vaccine candidates. Currently, assessment of infection in mice is performed by enumeration of inclusion-forming units (IFUs) through microscopic counting of fluorescently stained bacteria. We have developed a highly sensitive real-time quantitative polymerase chain reaction (RT-qPCR) assay for enumeration of Chlamydia from mouse genital tracts to increase assay sensitivity, remove subjectivity, and improve sample throughput. The qPCR assay uses a 16S ribosomal gene sequence that is conserved across Chlamydia species and serovars, resulting in detection of multiple serovars of C. trachomatis, as well as Chlamydia muridarum and Chlamydia pneumoniae. The PCR assay provided results similar to IFU enumeration (94% agreement between the 2 assays) and is highly sensitive and specific with less inherent subjectivity than traditional enumeration methods.
Collapse
Affiliation(s)
- Melissa A Wooters
- Vaccine Basic Research, Merck Research Laboratories, West Point, PA 19486-0004, USA.
| | | | | | | | | | | |
Collapse
|
35
|
Donati M, Laroucau K, Storni E, Mazzeo C, Magnino S, Di Francesco A, Baldelli R, Ceglie L, Renzi M, Cevenini R. Serological response to pgp3 protein in animal and human chlamydial infections. Vet Microbiol 2008; 135:181-5. [PMID: 18945555 DOI: 10.1016/j.vetmic.2008.09.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Specific antibodies to plasmid-encoded protein pgp3 are known to be encountered in human Chlamydia (C.) trachomatis infections. In order to verify whether antibodies to this protein could be developed in animals infected with plasmid-carrying chlamydial strains, 454 animal sera were examined using a home-made pgp3 protein ELISA and Western blots (WB) of recombinant pgp3 protein from Chlamydophila (Cp.) psittaci. Likewise, 50 human sera were tested by ELISA and WB of recombinant pgp3 from C. trachomatis. The reactivity against pgp3 protein was compared to the reactivity against chlamydial elementary bodies (EBs) detected by microimmunofluorescence (MIF) test. The presence of pgp3-specific antibodies was demonstrated in most ducks and pigeons with Cp. psittaci infection detected by MIF, as well as in the majority of symptomatic cats and pigs infected with Cp. felis and C. suis, respectively, which reacted at high titres to Cp. felis and C. suis EBs by MIF. Moreover, most of the sera collected from patients with C. trachomatis culture-confirmed infection and seropositive to C. trachomatis by MIF, presented antibodies specific to C. trachomatis pgp3 recombinant protein. Therefore, pgp3 protein could be a useful marker of chlamydial infections in animals, as well as in humans.
Collapse
Affiliation(s)
- Manuela Donati
- Section of Microbiology, DMCSS, University of Bologna, S. Orsola Hospital, Bologna, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
The Chlamydia trachomatis plasmid is a transcriptional regulator of chromosomal genes and a virulence factor. Infect Immun 2008; 76:2273-83. [PMID: 18347045 DOI: 10.1128/iai.00102-08] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis possesses a cryptic 7.5-kb plasmid of unknown function. Here, we describe a comprehensive molecular and biological characterization of the naturally occurring plasmidless human C. trachomatis strain L2(25667R). We found that despite minimal chromosomal polymorphisms, the LGV strain L2(25667R) was indistinguishable from plasmid-positive strain L2(434) with regard to its in vitro infectivity characteristics such as growth kinetics, plaquing efficiency, and plaque size. The only in vitro phenotypic differences between L2(434) and L2(25667R) were the accumulation of glycogen granules in the inclusion matrix and the lack of the typical intrainclusion Brownian-like movement characteristic of C. trachomatis strains. Conversely, we observed a marked difference between the two strains in their abilities to colonize and infect the female mouse genital tract. The 50% infective dose of plasmidless strain L2(25667R) was 400-fold greater (4 x 10(6) inclusion-forming units [IFU]) than that of plasmid-bearing strain L2(434) (1 x 10(4) IFU). Transcriptome analysis of the two strains demonstrated a decrease in the transcript levels of a subset of chromosomal genes for strain L2(25667R). Among those genes was glgA, encoding glycogen synthase, a finding consistent with the failure of L2(25667R) to accumulate glycogen granules. These findings support a primary role for the plasmid in in vivo infectivity and suggest that virulence is controlled, at least in part, by the plasmid's ability to regulate the expression of chromosomal genes. Our findings have important implications in understanding a role for the plasmid in the pathogenesis of human infection and disease.
Collapse
|
37
|
Interstrain gene transfer in Chlamydia trachomatis in vitro: mechanism and significance. J Bacteriol 2007; 190:1605-14. [PMID: 18083799 DOI: 10.1128/jb.01592-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The high frequency of between-strain genetic recombinants of Chlamydia trachomatis among isolates obtained from human sexually transmitted infections suggests that lateral gene transfer (LGT) is an important means by which C. trachomatis generates variants that have enhanced relative fitness. A mechanism for LGT in C. trachomatis has not been described, and investigation of this phenomenon by experimentation has been hampered by the obligate intracellular development of this pathogen. We describe here experiments that readily detected LGT between strains of C. trachomatis in vitro. Host cells were simultaneously infected with an ofloxacin-resistant (Ofx(r)) mutant of a serovar L1 strain (L1:Ofx(r)-1) and a rifampin-resistant (Rif(r)) mutant of a serovar D strain (D:Rif(r)-1). Development occurred in the absence of antibiotics, and the progeny were subjected to selection for Ofx(r) Rif(r) recombinants. The parental strains differed at many polymorphic nucleotide sites, and DNA sequencing was used to map genetic crossovers and to determine the parental sources of DNA segments in 14 recombinants. Depending on the assumed DNA donor, the estimated minimal length of the transferred DNA was > or = 123 kb in one recombinant but was > or = 336 to > or = 790 kb in all other recombinants. Such trans-DNA lengths have been associated only with conjugation in known microbial LGT systems, but natural DNA transformation remains a conceivable mechanism. LGT studies can now be performed with diverse combinations of C. trachomatis strains, and they could have evolutionary interest and yield useful recombinants for functional analysis of allelic differences between strains.
Collapse
|
38
|
Magbanua JPV, Goh BT, Michel CE, Aguirre-Andreasen A, Alexander S, Ushiro-Lumb I, Ison C, Lee H. Chlamydia trachomatis variant not detected by plasmid based nucleic acid amplification tests: molecular characterisation and failure of single dose azithromycin. Sex Transm Infect 2007; 83:339-43. [PMID: 17567684 PMCID: PMC2598672 DOI: 10.1136/sti.2007.026435] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2007] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To characterise a Chlamydia trachomatis variant strain from a patient with non-gonococcal urethritis (NGU) whose first void urine (FVU) displayed discrepant Ctrachomatis test results and describe the clinical response to treatment. METHODS The FVU specimen was assayed with an immune based Chlamydia Rapid Test (CRT) and various nucleic acid amplification tests (NAATs) to establish C trachomatis infection. Sequencing of the major outer membrane protein gene (omp1 also known as ompA) was undertaken to identify the serovar of the variant strain. Polymerase chain reaction (PCR) analysis was also conducted to determine whether the strain harboured deletions in the cryptic plasmid or was plasmid free. RESULTS The FVU specimen was strongly reactive in CRT but negative with the plasmid based Amplicor PCR (Roche) and ProbeTec ET (Becton-Dickinson) assays. However, NAATs for 16S RNA (Aptima Combo 2, GenProbe), omp1 (RealArt CT PCR, Artus and in-house NAATs) or the outer membrane complex B protein gene (omcB) established C trachomatis infection. Sequencing of omp1 showed that the variant belonged to serovar I. PCR analysis indicated that the variant was plasmid free. The patient did not respond to single dose azithromycin treatment but subsequently responded to a course of doxycycline. CONCLUSIONS A pathogenic plasmid free C trachomatis variant was identified. Clinicians should be alerted to the possibility of undetected C trachomatis infection caused by such variants and the potential of azithromycin failure in patients with recurrent chlamydial NGU. The occurrence of this variant is rare and should not form the basis for judgment of the performance or usefulness of plasmid based NAATs for C trachomatis detection.
Collapse
Affiliation(s)
- Jose Paolo V Magbanua
- Department of Haematology, University of Cambridge, EABC Site, Long Road, Cambridge CB2 2PT, UK
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Nucleic acid amplification technique for detection ofChlamydia trachomatis infection from clinical urogenital swabs. Folia Microbiol (Praha) 2007; 52:437-42. [DOI: 10.1007/bf02932100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
40
|
Gillespie JJ, Beier MS, Rahman MS, Ammerman NC, Shallom JM, Purkayastha A, Sobral BS, Azad AF. Plasmids and rickettsial evolution: insight from Rickettsia felis. PLoS One 2007; 2:e266. [PMID: 17342200 PMCID: PMC1800911 DOI: 10.1371/journal.pone.0000266] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Accepted: 02/08/2007] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The genome sequence of Rickettsia felis revealed a number of rickettsial genetic anomalies that likely contribute not only to a large genome size relative to other rickettsiae, but also to phenotypic oddities that have confounded the categorization of R. felis as either typhus group (TG) or spotted fever group (SFG) rickettsiae. Most intriguing was the first report from rickettsiae of a conjugative plasmid (pRF) that contains 68 putative open reading frames, several of which are predicted to encode proteins with high similarity to conjugative machinery in other plasmid-containing bacteria. METHODOLOGY/PRINCIPAL FINDINGS Using phylogeny estimation, we determined the mode of inheritance of pRF genes relative to conserved rickettsial chromosomal genes. Phylogenies of chromosomal genes were in agreement with other published rickettsial trees. However, phylogenies including pRF genes yielded different topologies and suggest a close relationship between pRF and ancestral group (AG) rickettsiae, including the recently completed genome of R. bellii str. RML369-C. This relatedness is further supported by the distribution of pRF genes across other rickettsiae, as 10 pRF genes (or inactive derivatives) also occur in AG (but not SFG) rickettsiae, with five of these genes characteristic of typical plasmids. Detailed characterization of pRF genes resulted in two novel findings: the identification of oriV and replication termination regions, and the likelihood that a second proposed plasmid, pRFdelta, is an artifact of the original genome assembly. CONCLUSION/SIGNIFICANCE Altogether, we propose a new rickettsial classification scheme with the addition of a fourth lineage, transitional group (TRG) rickettsiae, that is unique from TG and SFG rickettsiae and harbors genes from possible exchanges with AG rickettsiae via conjugation. We offer insight into the evolution of a plastic plasmid system in rickettsiae, including the role plasmids may have played in the acquirement of virulence traits in pathogenic strains, and the likely origin of plasmids within the rickettsial tree.
Collapse
Affiliation(s)
- Joseph J. Gillespie
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Magda S. Beier
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - M. Sayeedur Rahman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nicole C. Ammerman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Joshua M. Shallom
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
| | - Anjan Purkayastha
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
| | - Bruno S. Sobral
- Virginia Bioinformatics Institute at Virginia Tech, Blacksburg, Virginia, United States of America
| | - Abdu F. Azad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
41
|
Marshall R, Chernesky M, Jang D, Hook EW, Cartwright CP, Howell-Adams B, Ho S, Welk J, Lai-Zhang J, Brashear J, Diedrich B, Otis K, Webb E, Robinson J, Yu H. Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae. J Clin Microbiol 2007; 45:747-51. [PMID: 17202273 PMCID: PMC1829145 DOI: 10.1128/jcm.01956-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.
Collapse
Affiliation(s)
- R Marshall
- Abbott Molecular Inc., Des Plaines, IL 60018, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Demars R, Weinfurter J, Guex E, Lin J, Potucek Y. Lateral gene transfer in vitro in the intracellular pathogen Chlamydia trachomatis. J Bacteriol 2006; 189:991-1003. [PMID: 17122345 PMCID: PMC1797294 DOI: 10.1128/jb.00845-06] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic recombinants that resulted from lateral gene transfer (LGT) have been detected in sexually transmitted disease isolates of Chlamydia trachomatis, but a mechanism for LGT in C. trachomatis has not been described. We describe here a system that readily detects C. trachomatis LGT in vitro and that may facilitate discovery of its mechanisms. Host cells were simultaneously infected in the absence of antibiotics with an ofloxacin-resistant mutant and a second mutant that was resistant to lincomycin, trimethoprim, or rifampin. Selection for doubly resistant C. trachomatis isolates in the progeny detected apparent recombinant frequencies of 10(-4) to 10(-3), approximately 10(4) times more frequent than doubly resistant spontaneous mutants in progeny from uniparental control infections. Polyclonal doubly resistant populations and clones isolated from them in the absence of antibiotics had the specific resistance-conferring mutations present in the parental mutants; absence of the corresponding normal nucleotides indicated that they had been replaced by homologous recombination. These results eliminate spontaneous mutation, between-strain complementation, and heterotypic resistance as general explanations of multiply resistant C. trachomatis that originated in mixed infections in our experiments and demonstrate genetic stability of the recombinants. The kind of LGT we observed might be useful for creating new strains for functional studies by creating new alleles or combinations of alleles of polymorphic loci and might also disseminate antibiotic resistance genes in vivo. The apparent absence of phages and conjugative plasmids in C. trachomatis suggests that the LGT may have occurred by means of natural DNA transformation. Therefore, the experimental system may have implications for genetically altering C. trachomatis by means of DNA transfer.
Collapse
Affiliation(s)
- Robert Demars
- Laboratory of Genetics, University of Wisconsin, 555 Science Drive, Madison, WI 53711, USA.
| | | | | | | | | |
Collapse
|
43
|
Timms P, Eaves F, Hugall A, Lavin M. Plasmids of Chlamydia psittaci: Cloning and comparison of isolates by Southern hybridisation. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1988.tb02981.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
44
|
Davis BT, Thiim M, Zukerberg LR. Case records of the Massachusetts General Hospital. Case 2-2006. A 31-year-old, HIV-positive man with rectal pain. N Engl J Med 2006; 354:284-9. [PMID: 16421370 DOI: 10.1056/nejmcpc059038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
45
|
Pickett MA, Everson JS, Pead PJ, Clarke IN. The plasmids of Chlamydia trachomatis and Chlamydophila pneumoniae (N16): accurate determination of copy number and the paradoxical effect of plasmid-curing agents. Microbiology (Reading) 2005; 151:893-903. [PMID: 15758234 DOI: 10.1099/mic.0.27625-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A 7·5 kbp cryptic plasmid is found in almost all isolates of Chlamydia trachomatis. Real-time PCR assays, using TaqMan chemistry, were set up to quantify accurately both the chlamydial plasmid and the single copy, chromosomal omcB gene in the infectious, elementary bodies (EBs) of C. trachomatis L1 440. Plasmid copy number was also determined in the EBs of six other lymphogranuloma venereum (LGV) isolates (serovars L1–L3), ten trachoma isolates (serovars A–C) and nine urogenital isolates (serovars D–J). The results indicated an average plasmid copy number of 4·0±0·8 (mean±95 % confidence interval) plasmids per chromosome. During the chlamydial developmental cycle, up to 7·6 plasmids per chromosome were detected, indicating an increased plasmid copy number in the actively replicating reticulate bodies. Attempts to eliminate the plasmid from strain L1 440 using the plasmid-curing agents ethidium bromide, acridine orange or imipramine/novobiocin led to a paradoxical increase in plasmid copy number. It is speculated that the stress induced by chemical curing agents may stimulate the activity of plasmid-encoded replication (Rep) proteins. In contrast to C. trachomatis, only a single isolate of Chlamydophila pneumoniae bears a plasmid. C. pneumoniae strain N16 supports a 7·4 kbp plasmid in which ORF1, encoding one of the putative Rep proteins, is disrupted by a deletion and split into two smaller ORFs. Similar assay techniques revealed 1·3±0·2 plasmids per chromosome (mean±95 % confidence interval) in EBs of this strain. These findings are in agreement with the hypothesis that the ORF1-encoded protein is involved in, but not essential for, plasmid replication and control of copy number.
Collapse
Affiliation(s)
- Mark A Pickett
- Molecular Microbiology Group, University of Southampton Medical School, MP814, Southampton General Hospital, Hampshire SO16 6YD, UK
| | - J Sylvia Everson
- Molecular Microbiology Group, University of Southampton Medical School, MP814, Southampton General Hospital, Hampshire SO16 6YD, UK
| | - Patrick J Pead
- Molecular Microbiology Group, University of Southampton Medical School, MP814, Southampton General Hospital, Hampshire SO16 6YD, UK
| | - Ian N Clarke
- Molecular Microbiology Group, University of Southampton Medical School, MP814, Southampton General Hospital, Hampshire SO16 6YD, UK
| |
Collapse
|
46
|
Berg ES, Størvold G, Anestad G, Moi H, Skaug K. Reliability of the Amplicor internal control to disclose false-negative Chlamydia trachomatis PCR results. J Microbiol Methods 2004; 60:125-9. [PMID: 15567232 DOI: 10.1016/j.mimet.2004.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Accepted: 09/07/2004] [Indexed: 11/16/2022]
Abstract
Four possibly false-negative samples were detected when 514 male urine specimens were tested in the Amplicor Chlamydia trachomatis assay. In three of the four samples, the inhibition could be reduced by removal of urine supernatant. Under partially inhibitory conditions, after spiking with 50 C. trachomatis elementary bodies/ml specimen, a selective inhibition of the C. trachomatis target amplification and a preferential internal control amplification was observed. We conclude that a positive internal control signal might be misleading in inhibitory specimens with low amount of C. trachomatis.
Collapse
Affiliation(s)
- Einar S Berg
- SMAB, Division for Infectious Disease Control, Norwegian Institute of Public Health, PO Box 4404 Nydalen, N-0403 Oslo, Norway.
| | | | | | | | | |
Collapse
|
47
|
Solomon AW, Peeling RW, Foster A, Mabey DCW. Diagnosis and assessment of trachoma. Clin Microbiol Rev 2004; 17:982-1011, table of contents. [PMID: 15489358 PMCID: PMC523557 DOI: 10.1128/cmr.17.4.982-1011.2004] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Trachoma is caused by Chlamydia trachomatis. Clinical grading with the WHO simplified system can be highly repeatable provided graders are adequately trained and standardized. At the community level, rapid assessments are useful for confirming the absence of trachoma but do not determine the magnitude of the problem in communities where trachoma is present. New rapid assessment protocols incorporating techniques for obtaining representative population samples (without census preparation) may give better estimates of the prevalence of clinical trachoma. Clinical findings do not necessarily indicate the presence or absence of C. trachomatis infection, particularly as disease prevalence falls. The prevalence of ocular C. trachomatis infection (at the community level) is important because it is infection that is targeted when antibiotics are distributed in trachoma control campaigns. Methods to estimate infection prevalence are required. While culture is a sensitive test for the presence of viable organisms and nucleic acid amplification tests are sensitive and specific tools for the presence of chlamydial nucleic acids, the commercial assays presently available are all too expensive, too complex, or too unreliable for use in national programs. There is an urgent need for a rapid, reliable test for C. trachomatis to assist in measuring progress towards the elimination of trachoma.
Collapse
Affiliation(s)
- Anthony W Solomon
- Clinical Research Unit, London School of Hygiene & Tropical Medicine, Keppel St., London WC1E 7HT, United Kingdom.
| | | | | | | |
Collapse
|
48
|
Nicholson TL, Chiu K, Stephens RS. Chlamydia trachomatis lacks an adaptive response to changes in carbon source availability. Infect Immun 2004; 72:4286-9. [PMID: 15213176 PMCID: PMC427450 DOI: 10.1128/iai.72.7.4286-4289.2004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Most bacteria coordinately regulate gene expression as an adaptive response to a variety of environmental changes. One key environmental cue is the carbon source necessary for central metabolism. We used microarray analysis to monitor the global transcriptional response of the obligate intracellular pathogen Chlamydia trachomatis to the presence of glycolytic and gluconeogenic carbon sources. In contrast to free-living bacteria, changing the carbon source from glucose to glutamate or alpha-ketoglutarate had little effect on the global gene transcription of C. trachomatis.
Collapse
Affiliation(s)
- Tracy L Nicholson
- Program in Infectious Diseases, School of Public Health, University of California-Berkeley, 140 Earl Warren Hall, Berkeley, CA 94720-7360, USA
| | | | | |
Collapse
|
49
|
Østergaard L. Microbiological aspects of the diagnosis of Chlamydia trachomatis. Best Pract Res Clin Obstet Gynaecol 2002; 16:789-99. [PMID: 12473282 DOI: 10.1053/beog.2002.0322] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The available diagnostic methods for Chlamydia trachomatis infection comprise serology (indirect detection) and culture, antigen detection and nucleic acid amplification (direct detection). The rationale, applications, advantages and disadvantages of the methods and diagnostic targets are discussed. Compared to conventional methods, nucleic acid amplification tests have increased sensitivity. This allows samples to be taken at home by the patient herself and mailed directly to the laboratory. Public health strategies implying home sampling for asymptomatic men and women result in a lower prevalence and a lower risk of short-term complications in terms of pelvic inflammatory disease (PID). The importance of predictive values and the association with prevalence are highlighted.
Collapse
Affiliation(s)
- Lars Østergaard
- Department of Infectious Diseases, Skejby Sygehus, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| |
Collapse
|
50
|
Darwin LH, Cullen AP, Crowe SR, Modarress KJ, Willis DE, Payne WJ. Evaluation of the Hybrid Capture 2 CT/GC DNA tests and the GenProbe PACE 2 tests from the same male urethral swab specimens. Sex Transm Dis 2002; 29:576-80. [PMID: 12370524 DOI: 10.1097/00007435-200210000-00003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND A previous study demonstrated that Digene's Hybrid Capture 2 (HC2) DNA tests for detection of and (CT/GC) could be performed using cervical swab specimens collected in GenProbe transport media with significantly greater sensitivity for the detection of than with the GenProbe PACE 2 system. GOAL The goal was to assess the performance of HC2 tests in comparison with GenProbe PACE 2 tests for the detection of CT/GC in male urethral swab specimens. STUDY DESIGN A total of 1,202 male urethral swab specimens were collected in GenProbe PACE transport medium. All specimens were first tested with the PACE 2 system, followed by masked HC2 CT/GC testing. The GenProbe AMPLIFIED CT Assay (AMP CT) and PCR/SHARP Signal System (SHARP) were used for adjudication of discrepant results. RESULTS The prevalence rates for this population were 8.4% for and 14.6% for, based on the adjudicated results. The relative sensitivity and specificity for the detection of were 97.0% and 99.8% for HC2 and 69.3% and 98.3% for PACE 2, respectively. The relative sensitivities for the detection of were 98.9% for HC2 and 99.4% for PACE 2, with the same specificity of 99.9% for both tests. Agreement between the two testing methods was 95.4% for and 99.6% for. CONCLUSION The HC2 test is compatible with the GenProbe collection medium, with significantly greater sensitivity than the GenProbe PACE 2 test for detecting and similar sensitivities for detecting.
Collapse
Affiliation(s)
- Ling H Darwin
- Digene Corporation, Gaithersburg, Maryland 20878, USA
| | | | | | | | | | | |
Collapse
|