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Pang Y, Shui J, Li C, Li Y, Chen H, Tang S. The serodiagnositic value of Chlamydia trachomatis antigens in antibody detection using luciferase immunosorbent assay. Front Public Health 2024; 12:1333559. [PMID: 38476494 PMCID: PMC10927828 DOI: 10.3389/fpubh.2024.1333559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 02/14/2024] [Indexed: 03/14/2024] Open
Abstract
Introduction Among the different antigens used in the detection of anti-Chlamydia trachomatis antibodies, significant differences in sensitivity and specificity have been observed. Further evaluation of C. trachomatis antigens in antibody detection is urgently needed for the development and application of C. trachomatis serologic assays. Methods Chlamydia trachomatis antigens Pgp3, TmeA, InaC, and HSP60 were selected and used in luciferase immunosorbent assay (LISA). The detection results obtained from well-defined C. trachomatis positive and negative samples were compared with the commercial C. trachomatis ELISA (Mikrogen) for performance evaluation. Results Pgp3, TmeA, InaC, and HSP60-based LISA showed sensitivity of 92.8, 88.8, 90.4, and 94.4%, and specificity of 99.2, 99.2, 99.2, and 92%, respectively. ROC analysis indicated that Pgp3-based LISA showed similar performance to Mikrogen ELISA (AUC 0.986 vs. 0.993, p = 0.207). Furthermore, four C. trachomatis antigens achieved strong diagnostic efficiency, i.e., positive likelihood ratios [+LR] ≥ 10 in C. trachomatis-infected women and negative likelihood ratios [-LR] ≤ 0.1 in C. trachomatis negative low exposure risk children, but only Pgp3 and TmeA showed strong diagnostic value in general adults. In addition, Pgp3, TmeA, and InaC, but not HSP60, achieved high performance, i.e., both positive predictive value (PPV) and negative predictive value (NPV) ≥ 90.9%, and showed no significant cross-reactivity with anti-Chlamydiapneumoniae. Conclusion Three C. trachomatis species-specific antigens Pgp3, TmeA, and InaC show superior performance in the detection of anti-C. trachomatis antibody, indicating the potential to be used in developing C. trachomatis serologic tests.
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Affiliation(s)
- Yulian Pang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | - Jingwei Shui
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
- Department of Emergency, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Changchang Li
- Dermatology Hospital of Southern Medical University, Guangzhou, China
| | - Yongzhi Li
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | | | - Shixing Tang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
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Campaner AB, de Castro MA, Lucarelli AP. Chlamydia trachomatis prevalence in females in São Paulo, Brazil: 11 years' surveillance of the infection. Braz J Microbiol 2023; 54:151-158. [PMID: 36574206 PMCID: PMC9944148 DOI: 10.1007/s42770-022-00865-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 10/29/2022] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Chlamydia trachomatis (CT) infection is the most prevalent sexually transmitted bacterial disease worldwide whose greatest impact is on the female reproductive system. The objective was to assess the prevalence of Chlamydia infection in a large population of female patients from a private health service in São Paulo (Brazil), identifying the main age groups affected by the agent and the evolution of the prevalence. METHODS A cross-sectional study was conducted based on the results of all molecular biology tests. The tests were carried out between January 2005 and December 2015. The positivity of test results was determined by year and age group. RESULTS A total of 85,292 patients who performed 103,576 tests for Chlamydia were considered eligible for the statistical data. The overall prevalence of C. trachomatis infection in the study population was 2.2% (95% CI: 2.07-2.25). A higher prevalence of infection was observed in the ≤ 25 years and ≤ 30 years age groups, with rates of 6.0% (95% CI: 5.59-6.35) and 4.4% (95% CI: 4.08-4.50), respectively. There was a significant increase in the positivity of the exams over time, especially in the ≤ 35 years age group. The prevalence at 26-30 years was 3.1% (95% CI: 2.82-3.30); 31-35 years 1.7% (95% CI: 1.50-1.82); 36-40 years 1.0% (95% CI: 0.86-1.16); 41-60 years 0.6% (95% CI: 0.50-0.70) and the prevalence at ≥ 61 years was 0.4% (95% CI: 0.11-0.75). CONCLUSION The screening of asymptomatic young women would have the potential to reduce infection, transmission, and sequelae of infection by this agent.
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Affiliation(s)
- Adriana Bittencourt Campaner
- Department of Gynecology and Obstetrics, Santa Casa de São Paulo Medical School, Rua Dr Cesário Mota Jr, 112 - Vila Buarque, São Paulo, 01221- 020 Brazil
| | - Marco Antonio de Castro
- Department of Gynecology and Obstetrics, Santa Casa de São Paulo Medical School, Rua Dr Cesário Mota Jr, 112 - Vila Buarque, São Paulo, 01221- 020 Brazil
| | - Adrienne Pratti Lucarelli
- Department of Gynecology and Obstetrics, Santa Casa de São Paulo Medical School, Rua Dr Cesário Mota Jr, 112 - Vila Buarque, São Paulo, 01221- 020 Brazil
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Are ELISA and PCR Discrepancies in the Identification of Chlamydia pneumoniae Caused by the Presence of " Chlamydia-Related Bacteria"? Microorganisms 2023; 11:microorganisms11010187. [PMID: 36677479 PMCID: PMC9865915 DOI: 10.3390/microorganisms11010187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Chlamydia are Gram-negative, intracellular pathogens colonizing the epithelial mucosa. They cause primarily atypical pneumonia and have recently been associated with chronic diseases. Diagnostics rely almost exclusively on serological methods; PCR tests are used rarely because in patients with positive ELISA, it is nearly impossible to identify chlamydial DNA. To understand this issue, we elaborated a reliable and sensitive nested PCR method (panNPCR) for identifying all Chlamydiales species, not only in sputa, but also in clotted blood. Sequencing of the PCR product revealed that 41% of positive sputa samples and 66% of positive blood samples were not infected by Chlamydia but with "Chlamydia-related bacteria" such as Rhabdochlamydia sp., Parachlamydia sp., Protochlamydia sp., Neochlamydia sp., Mesochlamydia elodeae and lacustris, Piscichlamydia salmonis, and Estrella lausannensis. Consequently, we propose that there might be more than four human pathogenic Chlamydia species. We did not find any clear correlation between increased levels of antibodies and the presence of their DNA. Chlamydialles DNA was found in sputa samples from individuals positive for IgG or IgA but not in blood samples. Thus, elevated IgG and IgA levels are not reliable markers of chronic infection, and the presence of persistent forms should be proved by panNPCR. Apparently, the differences between ELISA and DNA amplification results have three main methodological reasons. The first one is the threshold occurrence of chlamydial genetic material in sputum and blood. The second one is the fact that a significant part of the samples can have DNA with sequences different from those of other species of the order Chlamydiales. The third one is the high background characteristic for ELISA, the absence of paired sera, and the vague interpretation of the gray zone.
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4
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Marques PX, Wand H, Nandy M, Tan C, Shou H, Terplan M, Mark K, Brotman RM, Wilson DP, Ravel J, Hsia RC, Bavoil PM. Serum antibodies to surface proteins of Chlamydia trachomatis as candidate biomarkers of disease: results from the Baltimore Chlamydia Adolescent/Young Adult Reproductive Management (CHARM) cohort. FEMS MICROBES 2022; 3:xtac004. [PMID: 37332497 PMCID: PMC10117858 DOI: 10.1093/femsmc/xtac004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 01/18/2022] [Accepted: 02/25/2022] [Indexed: 06/30/2024] Open
Abstract
We previously observed that the nine-member family of autotransported polymorphic membrane proteins (Pmps) of Chlamydia trachomatis is variably expressed in cell culture. Additionally, C. trachomatis-infected patients display variable Pmp-specific serum antibody profiles indirectly suggesting expression of unique Pmp profiles is an adaptive response to host-specific stimuli during infection. Here, we propose that the host response to Pmps and other outer surface proteins may correlate with disease severity. This study tests this hypothesis using an ELISA that measures serum IgG antibodies specific for the nine C. trachomatis Pmp subtypes and four immunodominant antigens (MOMP, OmcB, Hsp60, ClpP) in 265 participants of the Chlamydia Adolescent/Young Adult Reproductive Management (CHARM) cohort. More C. trachomatis-infected females displayed high Pmp-specific antibody levels (cut-off Indexes) than males (35.9%-40.7% of females vs. 24.2%-30.0% of males), with statistical significance for PmpC, F and H (P < 0.05). Differences in Pmp-specific antibody profiles were not observed between C. trachomatis-infected females with a clinical diagnosis of pelvic inflammatory disease (PID) and those without. However, a statistically significant association between high levels of OmcB-specific antibody and a PID diagnosis (P< 0.05) was observed. Using antibody levels as an indirect measure of antigen expression, our results suggest that gender- and/or site-specific (cervix in females vs. urethra in males) stimuli may control pmp expression in infected patients. They also support the possible existence of immune biomarkers of chlamydial infection associated with disease and underline the need for high resolution screening in human serum.
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Affiliation(s)
- Patricia X Marques
- Department of Microbial Pathogenesis, University of Maryland, 650 W. Baltimore St, Baltimore, MD 21201, USA
| | - Handan Wand
- The Kirby Institute, Wallace Wurth Bldg, High St., UNSW Sydney, Kensington, NSW, 2052, Australia
| | - Melissa Nandy
- Institute for Genome Science, University of Maryland, 670 W. Baltimore St, Baltimore, MD 21201, USA
| | - Chun Tan
- Department of Microbial Pathogenesis, University of Maryland, 650 W. Baltimore St, Baltimore, MD 21201, USA
| | - Huizhong Shou
- Department of Microbial Pathogenesis, University of Maryland, 650 W. Baltimore St, Baltimore, MD 21201, USA
| | - Mishka Terplan
- Department of Obstetrics & Gynecology, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA
| | - Katrina Mark
- Department of Pediatrics, University of Maryland, 655 W. Baltimore St., Baltimore, MD 21201, USA
| | - Rebecca M Brotman
- Institute for Genome Science, University of Maryland, 670 W. Baltimore St, Baltimore, MD 21201, USA
| | - David P Wilson
- Department of Infectious Disease Modelling, The Burnet Institute, 85 Commercial Rd, Melbourne, VIC, 3004, Australia
| | - Jacques Ravel
- Department of Microbiology and Immunology, University of Maryland, 685 W. Baltimore St, Baltimore, MD 21201, USA
- Institute for Genome Science, University of Maryland, 670 W. Baltimore St, Baltimore, MD 21201, USA
| | - Ru-ching Hsia
- Electron Microscopy Core Imaging Facility, University of Maryland, 660 W. Redwood St, Baltimore, MD 21201, USA
| | - Patrik M Bavoil
- Department of Microbial Pathogenesis, University of Maryland, 650 W. Baltimore St, Baltimore, MD 21201, USA
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5
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Nanomedicines for the topical treatment of vulvovaginal infections: Addressing the challenges of antimicrobial resistance. Adv Drug Deliv Rev 2021; 178:113855. [PMID: 34214638 DOI: 10.1016/j.addr.2021.113855] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/24/2021] [Accepted: 06/25/2021] [Indexed: 12/11/2022]
Abstract
Recent years have, surprisingly, witnessed an increase in incidence of sexually transmitted infections (STIs). At the same time, antimicrobial therapy came under the threat of ever rising antimicrobial resistance (AMR), resulting in STIs with extremely limited therapy options. In this review, we addressed the challenges of treating vaginal infections in an era of AMR. We focused on published work regarding nanomedicine destined for localized treatment of vaginal infections. Localized therapy offers numerous advantages such as assuring high drug concentration at the infection site, limiting systemic drug exposure that can lead to faster development of AMR reduction in the systemic side effects and potentially safe therapy in pregnancy. We provided a state-of-the-art overview of nanoformulations proposed to topically treat STIs, emphasizing the challenges and advantages of each type of nanocarriers, as well as issues of potential toxicity.
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6
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Rahman KS, Kaltenboeck B. Multipeptide Assays for Sensitive and Differential Detection of Anti-Chlamydia Trachomatis Antibodies. J Infect Dis 2021; 224:S86-S95. [PMID: 34396415 DOI: 10.1093/infdis/jiab016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Detection of anti-Chlamydia trachomatis (Ctr) antibodies is compromised by cross-reactivity and poor sensitivity of classic Ctr-antigens. We discovered 48 strongly reactive peptide antigens of Ctr-specific B-cell epitopes from 21 immunodominant proteins. In this study, we review the utility of peptide assays for diagnosis of Ctr infections. By combining many of these Ctr-specific B-cell epitopes from several proteins in separate or mixed multipeptide assays, they achieved vastly superior assay sensitivity and specificity over standard enzyme-linked immunosorbent assays. Such multipeptide assays eliminate cross-reactivities (false positives) and correct for stochastic gaps in antibody responses (false negatives). More importantly, we developed and validated a novel microarray platform in which hundreds of peptides from many proteins are spotted in a single reaction well. This offers the possibility of high-throughput screening of many candidate peptides for routine serological fingerprinting of Ctr infections. Discovery of optimal sets of antibody responses that associate with clinical pelvic inflammatory disease (PID) may identify diagnostically useful PID biomarker antigens.
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Affiliation(s)
- Kh Shamsur Rahman
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Bernhard Kaltenboeck
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
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7
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Reliable and Sensitive Nested PCR for the Detection of Chlamydia in Sputum. Microorganisms 2021; 9:microorganisms9050935. [PMID: 33925646 PMCID: PMC8145989 DOI: 10.3390/microorganisms9050935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/25/2021] [Accepted: 04/25/2021] [Indexed: 11/16/2022] Open
Abstract
Chlamydia are Gram-negative, intracellular pathogens colonizing epithelial mucosa. They cause primarily atypical pneumonia and have recently been associated with chronic diseases. Diagnostics relies almost exclusively on serological methods; PCR tests are used rarely because in patients with positive ELISA, it is nearly impossible to identify chlamydial DNA. This paradox is associated with DNA degradation in sputum samples, low abundance, and low sensitivity of PCR systems. In a newly designed and validated “nested” PCR (NPCR) assay, it was possible to amplify DNA of Chlamydia known to infect humans in 31% samples. The reliability of the assay was confirmed by DNA sequencing, and all PCR products belonged exclusively to the Chlamydiales, mainly recognized as Chlamydia pneumoniae. Three samples were related to Ca. Rhabdochlamydia porcellionis and Ca. Renichlamydia lutjani, which infect arthropods. In one case, samples were taken from sick individual, indicating the potential as a human pathogen.
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8
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Liposomes-In-Hydrogel Delivery System Enhances the Potential of Resveratrol in Combating Vaginal Chlamydia Infection. Pharmaceutics 2020; 12:pharmaceutics12121203. [PMID: 33322392 PMCID: PMC7764002 DOI: 10.3390/pharmaceutics12121203] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 12/18/2022] Open
Abstract
Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infections and causes serious reproductive tract complications among women. The limitations of existing oral antibiotics and treatment of antimicrobial resistance require alternative treatment options. We are proposing, for the first time, the natural polyphenol resveratrol (RES) in an advanced delivery system comprising liposomes incorporated in chitosan hydrogel, for the localized treatment of C. trachomatis infection. Both free RES and RES liposomes-in-hydrogel inhibited the propagation of C. trachomatis in a concentration-dependent manner, assessed by the commonly used in vitro model comprising McCoy cells. However, for lower concentrations, the anti-chlamydial effect of RES was enhanced when incorporated into a liposomes-in-hydrogel delivery system, with inhibition of 78% and 94% for 1.5 and 3 µg/mL RES, respectively for RES liposomes-in-hydrogel, compared to 43% and 72%, respectively, for free RES. Furthermore, RES liposomes-in-hydrogel exhibited strong anti-inflammatory activity in vitro, in a concentration-dependent inhibition of nitric oxide production in the LPS-induced macrophages (RAW 264.7). The combination of a natural substance exhibiting multi-targeted pharmacological properties, and a delivery system that provides enhanced activity as well as applicability for vaginal administration, could be a promising option for the localized treatment of C. trachomatis infection.
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9
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Rahman KS, Kaltenboeck B. Multi-peptide ELISAs overcome cross-reactivity and inadequate sensitivity of conventional Chlamydia pneumoniae serology. Sci Rep 2019; 9:15078. [PMID: 31636331 PMCID: PMC6803651 DOI: 10.1038/s41598-019-51501-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022] Open
Abstract
Cross-reactivity of classical chlamydial antigens compromises Chlamydia (C.) pneumoniae serology. By testing with 185 human antisera, we expanded 18 previously discovered C. pneumoniae-specific B-cell epitopes to 48 peptide antigens from 12 C. pneumoniae immunodominant proteins. For specific detection of antibodies against C. pneumoniae, we developed novel ELISAs with strongly reactive individual peptide antigens and mixtures of these peptides. By comparison to a composite reference standard (CRS) for anti-C. pneumoniae antibody status of human sera, the top-performing CpnMixF12 peptide assay showed 91% sensitivity at 95% specificity, significantly higher than 4 commercial anti-C. pneumoniae IgG ELISAs (36-12% sensitivity at 95% specificity). Human C. pneumoniae (Cpn) and C. trachomatis (Ctr) seroreactivity was 54% biased towards co-positivity in commercial Cpn and Ctr ELISAs, but unbiased in Cpn and Ctr peptide antibody assays, suggesting severe cross-reactivity of commercial ELISAs. Using hyperimmune mouse sera against each of 11 Chlamydia spp., we confirm that commercial Cpn and Ctr ELISA antigens are cross-reactive among all Chlamydia spp., but Cpn and Ctr peptide antigens react only with antisera against the cognate chlamydial species. With simultaneously high specificity and sensitivity, and convenient use for non-specialized laboratories, these ELISAs have the potential to improve serodiagnosis of C. pneumoniae infection.
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Affiliation(s)
- Kh Shamsur Rahman
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA.
| | - Bernhard Kaltenboeck
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA
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Mixed Chlamydia trachomatis Peptide Antigens Provide a Specific and Sensitive Single-Well Colorimetric Enzyme-Linked Immunosorbent Assay for Detection of Human Anti -C. trachomatis Antibodies. mSphere 2018; 3:3/6/e00484-18. [PMID: 30404936 PMCID: PMC6222056 DOI: 10.1128/msphere.00484-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
For detection of anti-C. trachomatis antibodies by serological assays, use of classical chlamydial antigens results in high cross-reactivity and poor sensitivity. Previously, we discovered 48 strongly reactive peptide antigens of C. trachomatis-specific B-cell epitopes from 21 immunodominant proteins, and individual testing and combined scoring of 5 to 11 peptide antigens provided highly sensitive and specific detection of anti-C. trachomatis antibodies in chemiluminescent ELISAs. To simplify this method, this study established a single-well labor-saving colorimetric ELISA using a mixture of 12 strongly reactive C. trachomatis peptide antigens (Ctr Mix1) for detection of anti-C. trachomatis antibodies. This Ctr Mix1 ELISA (94% sensitivity and 98% specificity) outperformed 4 commercial ELISAs (49% to 79% sensitivity and 98% specificity). This ELISA can be easily implemented and commercialized, with convenient setup for use in nonspecialized laboratories. Thus, this mixed peptide assay with superior specificity and sensitivity will improve serodiagnosis of C. trachomatis infections. Sensitive and specific detection of anti-Chlamydia trachomatis antibodies in standard enzyme-linked immunosorbent assays (ELISAs) is compromised by cross-reactivity and poor sensitivity of classical C. trachomatis antigens. Previously, we discovered 48 strongly reactive peptide antigens of C. trachomatis-specific B-cell epitopes from 21 immunodominant proteins. By comprehensive individual testing of 11 top-ranked peptide antigens, we found very high sensitivity and specificity for detection of anti-C. trachomatis antibodies in chemiluminescent ELISAs. The current study established a labor-saving colorimetric ELISA by using a mixture of 12 strongly reactive C. trachomatis peptide antigens (Ctr Mix1) in a single well/serum rather than assaying reactivity to each individual peptide. For performance evaluation, we used a simulated population of 212 anti-C. trachomatis antibody-positive and -negative sera from 125 women with NAAT-confirmed active C. trachomatis infection and from 87 healthy women at low risk for C. trachomatis infection. In comparison to a composite reference standard (CRS) for anti-C. trachomatis antibody status, the Ctr Mix1 IgG ELISA achieved 93.9% sensitivity, significantly superior to the 49% to 79% sensitivities of four commercial anti-C. trachomatis IgG ELISAs, and 98% specificity of all tested assays. Compared to the labor-intensive individual peptide testing, this mixed peptide ELISA retained high specificity with only marginal, ∼5% sensitivity loss. By ROC-AUC, likelihood ratio, and predictive value analyses, the Ctr Mix1 ELISA performed satisfactorily at 10% to 75% prevalence range of anti-C. trachomatis antibodies but significantly better than commercial ELISAs. Thus, the labor-saving mixed peptide colorimetric ELISA format provides simultaneously high specificity and sensitivity for detection of anti-C. trachomatis antibodies. IMPORTANCE For detection of anti-C. trachomatis antibodies by serological assays, use of classical chlamydial antigens results in high cross-reactivity and poor sensitivity. Previously, we discovered 48 strongly reactive peptide antigens of C. trachomatis-specific B-cell epitopes from 21 immunodominant proteins, and individual testing and combined scoring of 5 to 11 peptide antigens provided highly sensitive and specific detection of anti-C. trachomatis antibodies in chemiluminescent ELISAs. To simplify this method, this study established a single-well labor-saving colorimetric ELISA using a mixture of 12 strongly reactive C. trachomatis peptide antigens (Ctr Mix1) for detection of anti-C. trachomatis antibodies. This Ctr Mix1 ELISA (94% sensitivity and 98% specificity) outperformed 4 commercial ELISAs (49% to 79% sensitivity and 98% specificity). This ELISA can be easily implemented and commercialized, with convenient setup for use in nonspecialized laboratories. Thus, this mixed peptide assay with superior specificity and sensitivity will improve serodiagnosis of C. trachomatis infections.
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Abstract
Current serological assays for species-specific detection of anti-Chlamydia species antibodies suffer from well-known shortcomings in specificity and ease of use. Due to the high prevalences of both anti-C. trachomatis and anti-C. pneumoniae antibodies in human populations, species-specific serology is unreliable. Therefore, novel specific and simple assays for chlamydial serology are urgently needed. Conventional antigens are problematic due to extensive cross-reactivity within Chlamydia spp. Using accurate B cell epitope prediction and a robust peptide ELISA methodology developed in our laboratory, we identified immunodominant C. trachomatis B cell epitopes by screening performed with sera from C. trachomatis-infected women. We discovered 38 novel human host-dependent antigens from 20 immunodominant C. trachomatis proteins, in addition to confirming 10 host-independent mouse serum peptide antigens that had been identified previously. This extended set of highly specific C. trachomatis peptide antigens can be used in simple ELISA or multiplexed microarray formats and will provide high specificity and sensitivity to human C. trachomatis serodiagnosis. Chlamydia species-specific serology is compromised by cross-reactivity of the gold standard microimmunofluorescence (MIF) or commercial enzyme-linked immunosorbent assays (ELISAs). This study was conducted to discover novel C. trachomatis-specific peptide antigens that were recognized only by the antibody response of the natural human host. We evaluated a library of 271 peptide antigens from immunodominant C. trachomatis proteins by reactivity with 125 C. trachomatis antibody-positive sera from women with PCR-confirmed C. trachomatis infection and 17 C. trachomatis antibody-negative sera from low-risk women never diagnosed with C. trachomatis infection. These C. trachomatis peptide antigens had been predicted in silico to contain B cell epitopes but had been nonreactive with mouse hyperimmune sera against C. trachomatis. We discovered 38 novel human host-dependent antigens from 20 immunodominant C. trachomatis proteins (PmpD, IncE, IncG, CT529, CT618, CT442, TarP, CT143, CT813, CT795, CT223, PmpC, CT875, CT579, LcrE, IncA, CT226, CT694, Hsp60, and pGP3). Using these human sera, we also confirmed 10 C. trachomatis B cell epitopes from 6 immunodominant C. trachomatis proteins (OmpA, PmpD, IncE, IncG, CT529, and CT618) as host species-independent epitopes that had been previously identified by their reactivity with mouse hyperimmune sera against C. trachomatis. ELISA reactivities against these peptides correlated strongly with the C. trachomatis microimmunofluorescence (MIF) text results (Pearson’s correlation coefficient [R] = 0.80; P < 10−6). These C. trachomatis peptide antigens do not cross-react with antibodies against other Chlamydia species and are therefore suitable for species-specific detection of antibodies against C. trachomatis. This study identified an extended set of peptide antigens for simple C. trachomatis-specific ELISA serology. IMPORTANCE Current serological assays for species-specific detection of anti-Chlamydia species antibodies suffer from well-known shortcomings in specificity and ease of use. Due to the high prevalences of both anti-C. trachomatis and anti-C. pneumoniae antibodies in human populations, species-specific serology is unreliable. Therefore, novel specific and simple assays for chlamydial serology are urgently needed. Conventional antigens are problematic due to extensive cross-reactivity within Chlamydia spp. Using accurate B cell epitope prediction and a robust peptide ELISA methodology developed in our laboratory, we identified immunodominant C. trachomatis B cell epitopes by screening performed with sera from C. trachomatis-infected women. We discovered 38 novel human host-dependent antigens from 20 immunodominant C. trachomatis proteins, in addition to confirming 10 host-independent mouse serum peptide antigens that had been identified previously. This extended set of highly specific C. trachomatis peptide antigens can be used in simple ELISA or multiplexed microarray formats and will provide high specificity and sensitivity to human C. trachomatis serodiagnosis.
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Comprehensive Molecular Serology of Human Chlamydia trachomatis Infections by Peptide Enzyme-Linked Immunosorbent Assays. mSphere 2018; 3:3/4/e00253-18. [PMID: 30068559 PMCID: PMC6070734 DOI: 10.1128/msphere.00253-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
For detection of anti-Chlamydia trachomatis antibodies by serological assays, use of classical whole-organism chlamydial antigens results in high cross-reactivity. These antigens bind mainly antibodies against the major outer membrane protein (OmpA) and bind antibodies against other immunodominant non-OmpA proteins to a lesser extent, resulting in poor assay sensitivity. The specificity of C. trachomatis serology is also compromised by the high prevalence of cross-reactive anti-C. pneumoniae antibodies in human populations. We previously identified 48 highly specific C. trachomatis B cell epitope peptide antigens of 21 immunodominant proteins. This study validated peptide antigen-based novel ELISAs that provide highly specific and sensitive detection of anti-C. trachomatis antibodies. Compared to four commercial ELISAs that achieved only poor sensitivities (51.5% to 64.8%), the combined signals of 5 to 11 peptides provided high sensitivity (86.5% to 91.8%) at the same 98% specificity. Thus, by using multiple peptide antigens of immunodominant proteins, we created simple ELISAs with specificity and sensitivity superior to standard C. trachomatis serodiagnosis. Sensitive species-specific detection of anti-Chlamydia trachomatis antibodies is compromised by cross-reactivity of the C. trachomatis antigens used in standard microimmunofluorescence (MIF) testing and enzyme-linked immunosorbent assays (ELISAs). Previously, we discovered 48 strongly reactive C. trachomatis-specific B cell epitope peptides from 21 immunodominant proteins. Here we comprehensively evaluated the 11 top-ranked C. trachomatis-specific peptide antigens from 8 proteins for use in C. trachomatis serology. Sera from 125 women with nucleic acid amplification test (NAAT)-confirmed active C. trachomatis infection and from 49 healthy women with a low risk of C. trachomatis infection were used as anti-C. trachomatis antibody-positive and -negative sera. Results obtained for detection of IgG1, IgG3, and IgA1 antibodies against the 11 C. trachomatis peptide antigens were compared to results from 4 commercial anti-C. trachomatis IgG ELISAs. Using composite reference standards (CRS) of all assays for anti-C. trachomatis antibody status, commercial ELISAs detected antibodies in antibody-positive women with sensitivities of 51.5% to 64.8%. In contrast, a combination of the results of all 11 peptides detected IgG (IgG1 and IgG3) antibodies with 91.8% sensitivity, and a labor-saving combination of the 5 optimal peptides still detected antibodies in antibody-positive women with 86.5% sensitivity (all at 98% specificity). The superior performance of the combined peptide ELISAs was confirmed by area under the receiver operating characteristic curve (ROC-AUC), likelihood ratio, and predictive value analyses. The higher sensitivity of the peptide assays results from using multiple B cell epitopes of several C. trachomatis immunodominant proteins, including OmpA, compared to exclusively using the OmpA antigens used in commercial ELISAs. Thus, ELISAs with combined use of synthetic peptide antigens for C. trachomatis antibody detection have the advantage of simultaneous high sensitivity and high specificity. IMPORTANCE For detection of anti-Chlamydia trachomatis antibodies by serological assays, use of classical whole-organism chlamydial antigens results in high cross-reactivity. These antigens bind mainly antibodies against the major outer membrane protein (OmpA) and bind antibodies against other immunodominant non-OmpA proteins to a lesser extent, resulting in poor assay sensitivity. The specificity of C. trachomatis serology is also compromised by the high prevalence of cross-reactive anti-C. pneumoniae antibodies in human populations. We previously identified 48 highly specific C. trachomatis B cell epitope peptide antigens of 21 immunodominant proteins. This study validated peptide antigen-based novel ELISAs that provide highly specific and sensitive detection of anti-C. trachomatis antibodies. Compared to four commercial ELISAs that achieved only poor sensitivities (51.5% to 64.8%), the combined signals of 5 to 11 peptides provided high sensitivity (86.5% to 91.8%) at the same 98% specificity. Thus, by using multiple peptide antigens of immunodominant proteins, we created simple ELISAs with specificity and sensitivity superior to standard C. trachomatis serodiagnosis.
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Sharma L, Losier A, Tolbert T, Dela Cruz CS, Marion CR. Atypical Pneumonia: Updates on Legionella, Chlamydophila, and Mycoplasma Pneumonia. Clin Chest Med 2016; 38:45-58. [PMID: 28159161 DOI: 10.1016/j.ccm.2016.11.011] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Community-acquired pneumonia (CAP) has multiple causes and is associated with illness that requires admission to the hospital and mortality. The causes of atypical CAP include Legionella species, Chlamydophila, and Mycoplasma. Atypical CAP remains a diagnostic challenge and, therefore, likely is undertreated. This article reviews the advancements in the evaluation and treatment of patients and discusses current conflicts and controversies of atypical CAP.
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Affiliation(s)
- Lokesh Sharma
- Section of Pulmonary, Critical Care and Sleep Medicine, Yale University School of Medicine, 300 Cedar Street, TAC S440, New Haven, CT 06510, USA
| | - Ashley Losier
- Department of Internal Medicine, Norwalk Hospital, 34 Maple Street, Norwalk, CT 06856, USA
| | - Thomas Tolbert
- Department of Internal Medicine, Yale University School of Medicine, 330 Cedar Street, New Haven, CT 06510, USA
| | - Charles S Dela Cruz
- Section of Pulmonary, Critical Care and Sleep Medicine, Yale University School of Medicine, 300 Cedar Street, TAC S440, New Haven, CT 06510, USA
| | - Chad R Marion
- Section of Pulmonary, Critical Care and Sleep Medicine, Yale University School of Medicine, 300 Cedar Street, TAC S440, New Haven, CT 06510, USA.
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Mbwele B, Slot A, De Mast Q, Kweka P, Msuya M, Hulscher M. The Use of Guidelines for Lower Respiratory Tract Infections in Tanzania: A Lesson from Kilimanjaro Clinicians. Ann Med Health Sci Res 2016; 6:100-8. [PMID: 27213093 PMCID: PMC4866362 DOI: 10.4103/2141-9248.181845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Evaluations of the guidelines for the management of Lower Respiratory Tract Infections (LRTI) Sub-Saharan Africa, particularly in Tanzania is scant. Aim: The aim of the study was to assess the usefulness of the current Tanzanian treatment guideline for the management lower respiratory tract infection. Subjects and Methods: A descriptive cross sectional study in 11 hospitals of different levels in the Kilimanjaro region Data were collected from May 2012 to July 2012 by semi-structured interview for clinicians using 2 dummy cases for practical assessment. Data were analyzed by STATA v11 (StataCorp, TX, USA). Qualitative narratives from the interviews were translated, transcribed then coded by colors into meaningful themes. Results: A variety of principles for diagnosing and managing LRTI were demonstrated by 53 clinicians of Kilimanjaro. For the awareness, 67.9% (36/53) clinicians knew their responsibility to use Standard Treatment Guideline for managing LRTI. The content derived from Standard Treatment Guideline could be cited by 11.3% of clinicians (6/53) however they all showed concern of gaps in the guideline. Previous training in the management of patients with LRTI was reported by 25.9% (14/53), majority were pulmonary TB related. Correct microorganisms causing different forms of LRTI were mentioned by 11.3% (6/53). Exact cause of Atypical pneumonia and Q fever as an example was stated by 13.0% (7/53) from whom the need of developing the guideline for LRTI was explicitly elaborated. Conclusion: The current guidelines have not been used effectively for the management of LRTI in Tanzania. There is a need to review its content for the current practical use.
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Affiliation(s)
- B Mbwele
- Kilimanjaro Christian Medical Center, Kilimanjaro Clinical Research Institute, Zanzibar, Tanzania; Programme Manager - Reproductive Maternal Newborn Child Health, Nutrition and WASH, Save the Children, Zanzibar, Tanzania
| | - A Slot
- Nijmegen Institute for International Health (NIIH, UMC Nijmegen), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Q De Mast
- Nijmegen Institute for International Health (NIIH, UMC Nijmegen), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - P Kweka
- Vijiji International, Kilimani Tower, Mawenzi Road, Moshi, Tanzania
| | - M Msuya
- Faculty of Nursing, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - M Hulscher
- Scientific Institute for Quality of Healthcare (IQ Healthcare), Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Borel N, Pospischil A, Hudson AP, Rupp J, Schoborg RV. The role of viable but non-infectious developmental forms in chlamydial biology. Front Cell Infect Microbiol 2014; 4:97. [PMID: 25105096 PMCID: PMC4109588 DOI: 10.3389/fcimb.2014.00097] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 07/04/2014] [Indexed: 12/16/2022] Open
Affiliation(s)
- Nicole Borel
- Department of Pathobiology, Institute of Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Andreas Pospischil
- Department of Pathobiology, Institute of Veterinary Pathology, University of Zurich Zurich, Switzerland
| | - Alan P Hudson
- Department of Immunology and Microbiology, Wayne State University School of Medicine Michigan, MI, USA
| | - Jan Rupp
- Department of Molecular and Clinical Infectious Diseases, University Hospital Schleswig-Holstein/Campus Lübeck Lübeck, Germany
| | - Robert V Schoborg
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University Johnson City, TN, USA
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