Chlamydia trachomatis genotypes associated with pneumonia in Chilean infants

Evaluation of Chlamydia trachomatis screening from the perspective of health economics: a systematic review

Background

Most Chlamydia trachomatis (CT) infections are asymptomatic. The infection can persist and lead to severe sequelae. Therefore, screening for CT can primarily prevent serious sequelae.

Aim

To systematically evaluate CT screening from the perspective of health economics, summarize previous findings from different target populations, and make practical recommendations for developing local CT screening strategies.

Methods

PubMed, Web of Science, Embase, Cochran Library, and National Health Service Economic Evaluation Database (Ovid) were searched from January 1, 2000, to March 4, 2023. Studies reporting the cost-effectiveness, cost-benefit, or cost-utility of CT screening were eligible to be included. A narrative synthesis was used to analyze and report the results following the PRISMA guidelines. The Consensus on Health Economic Criteria (CHEC) list was used to assess the methodological quality of included studies.

Results

Our review finally comprised 39 studies addressing four populations: general sexually active people (n = 25), pregnant women (n = 4), women attending STD and abortion clinics (n = 4), and other high-risk individuals (n = 6). The total number of participants was ~7,991,198. The majority of studies assessed the cost-effectiveness or cost-utility of the screening method. The results showed that the following screening strategies may be cost-effective or cost-saving under certain conditions: performing CT screening in young people aged 15-24 in the general population, military recruits, and high school students; incorporating CT screening into routine antenatal care for pregnant women aged 15-30; opportunistic CT screening for women attending STD and abortion clinics; home-obtained sampling for CT screening using urine specimens or vaginal swab; performing CT screening for 14-30-year-old people who enter correctional institutions (i.e., jail, detention) as soon as possible; providing CT screening for female sex workers (FSWs) based on local incidence and prevalence; adding routine CT screening to HIV treatment using rectal samples from men who have sex with men (MSM).

Conclusion

We found that CT screening in general sexually active people aged 15-24, military recruits, high school students, pregnant women aged 15-30, women attending STD and abortion clinics, people entering jail, detention, FSWs, and MSM has health economic value. Due to the different prevalence of CT, diversities of economic conditions, and varying screening costs among different populations and different countries, regions, or settings, no uniform and standard screening strategies are currently available. Therefore, each country should consider its local condition and the results of health economic evaluations of CT screening programs in that country to develop appropriate CT screening strategies.

Identification of Chlamydia trachomatis genotypes in newborns with respiratory distress

INTRODUCTION

One hundred thirty million Chlamydia trachomatis infections are reported worldwide each year. Nineteen serotypes of this pathogen can cause infection in pregnant women and neonates. The distribution of these genotypes in newborns with respiratory infections in Mexico is unknown.

MATERIAL AND METHODS

We tested 1062 bronchial lavage samples from neonates with respiratory distress syndrome for Chlamydia infection. The diagnosis of Chlamydia was made by plasmid detection with an in-house PCR assay, and genotypes were identified using a PCR-RFLP assay for the ompA gene.

RESULTS

The genotyping of 40 strains identified 14 as I/Ia (35%), 13 as E (32.5%), 7 as D (17.5%), 5 as F (12.5%), and 1 as L2 (2.5%). The relative risk analysis showed that genotype D was associated with neonatal sepsis (RR, 5.83; 95% confidence interval [CI], 1.51-25.985; P < .02), while the I/Ia genotype was significantly associated with chorioamnionitis in the mother (2.8; 95% CI, 1.4-5.5; P < .05).

CONCLUSIONS

Although C. trachomatis genotypes I/Ia and E of were the strains involved most frequently in respiratory infections in Mexican neonates, 80% of patients with genotype F developed respiratory disease. In contrast, genotype D was associated with neonatal sepsis, and genotype I/Ia with chorioamnionitis.

Regulation of chlamydial colonization by IFNγ delivered via distinct cells

The mouse-adapted pathogen Chlamydia muridarum (CM) induces pathology in the mouse genital tract but fails to do so in the gastrointestinal tract. CM is cleared from both the genital tract and small intestine by IFNγ delivered by antigen-specific CD4+ T cells but persists for a long period in the large intestine. The long-lasting colonization of CM in the large intestine is regulated by IFNγ delivered by group 3 innate lymphoid cells (ILC3s). Interestingly, the ILC3-delivered IFNγ can inhibit the human pathogen Chlamydia trachomatis (CT) in the mouse endometrium. Thus, IFNγ produced/delivered by different cells may selectively restrict chlamydial colonization in different tissues. Revealing the underlying mechanisms of chlamydial interactions with IFNγ produced by different cells may yield new insights into both chlamydial pathogenicity and mucosal immunity.

Development of a duplex recombinase-aided amplification assay for direct detection of Mycoplasma pneumoniae and Chlamydia trachomatis in clinical samples

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.

Opportunities and pitfalls of molecular testing for detecting sexually transmitted pathogens

In the last 20 years, nucleic acid amplification tests (NAATs) have gradually replaced traditional methods for the detection of sexually transmitted infections. NAAT technology comes with some considerable benefits for diagnosis, including increased sensitivity, rapid result turnaround and suitability for high throughput screening of asymptomatic individuals using more-readily available specimens. However, the transition to NAAT has not come without its problems. False-negative and false-positive results have been reported owing to various technical issues. Furthermore, increased reliance on NAATs for diagnosis have created the need to develop NAAT-based methods to inform treatment, being an area that presents its own set of challenges. In this review article, we explore NAAT-based detection of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis. In doing so, we consider the benefits and limitations of NAAT-based technology and highlight areas where further research and development is in need.

Chlamydia trachomatis genovars causing urogenital infections in Santiago, Chile

BACKGROUND

Chlamydia trachomatis is a common sexually transmitted infection in Chile, but little is known about the genovar distribution in genital infections. Thus, the objective of this study was to determine the distribution of C. trachomatis genovars in such cases.

METHODS

A total of 522 urogenital specimens, 403 from women and 119 from men, were analyzed for C. trachomatis by nested polymerase chain reaction (PCR) targeting of the ompA gene. Positive specimens were genotyped by DNA sequencing of the amplicons.

RESULTS

Sixty-two (11.9%) specimens were positive. Of these, 43 (69.4%) were collected from men and 19 (30.6%) from women (p < 0.0001). Eight genovars were identified in men and seven in women. Genovar E was the most common in both men and women, followed by genovar Da in men, and F in women. Together these three genovars accounted for 84% of infections. Genovar D was the third most common genovar (n = 4). Genovar G was detected in two samples, and sequences of genovars Ba, H, and Ja were each found in single samples. One sample (1.6%) contained mixed sequences. No association was found between gender and specific genovars. Fifty-six (92%) sequences were identical to those reported for the respective reference genovars and the other two have been described in several regions.

CONCLUSIONS

Our findings add to the results of most studies, which indicate that genovars E, F, and D/Da are the most frequent. No association was found between gender and specific genovars. Despite the heterogeneous population of genovars, most ompA sequences were conserved.

The clinical characteristics and genotype distribution of Chlamydia trachomatis infection in infants less than six months of age hospitalized with pneumonia

BACKGROUND

Chlamydia trachomatis is a common sexually-transmitted bacterial pathogen. As no routine screening is performed during pregnancy, neonates and infants are at high risk for C. trachomatis infection. The objective of this study was to investigate the morbidity, clinical characteristics and genotype distribution of C. trachomatis pneumonia in infants less than six months of age.

METHODS

Clinical manifestations and laboratory results were recorded. Respiratory sputum specimens were tested using RT-PCR targeting C. trachomatis cryptic plasmid. Simultaneously, respiratory virus antigens were detected by direct immunofluorescence and bacterial pathogens were examined by culture in all sputum samples. Positive C. trachomatis samples were further genotyped using a multiplex PCR reverse line blot assay. The relationship between genotype and pneumonia severity was explored.

RESULTS

Of 1408 infants, 101 (7.2%) were infected with C. trachomatis. Sixteen of 101 (15.8%) were assessed as severe pneumonia. These severe cases had a higher proportion of viral co-infection (37.5%) compared to mild pneumonia cases (9.4%, P<0.05).Infants with tachypnea (OR 9.2) and wheezing (OR 3.5) were more likely to be classified as severe pneumonia (P<0.05). Amongst 66 C. trachomatis specimens for which a genotyping result was available, seven genotypes were detected, and 39.4% of these specimens contained two or three genotypes. Overall, genotype E (48.5%) was the most frequent, followed by genotype F (42.4%), J (31.8%), D (12.1%), K (10.6%), G (4.5%) and H (3.0%). There were no significant correlations of particular genotypes with severity of disease, although there was a weak indication that more severe pneumonia might be associated with having certain mixed genotypes of C. trachomatis.

CONCLUSIONS

The prevalence of C. trachomatis in the population of young hospitalized infants with pneumonia in Shenzhen was very high. The relationship between genotype distribution and severity of pneumonia was not clear based on this study due to small sample size. Further in-depth investigation correlating genotype and disease severity based on a larger population is needed.

A literature review and survey of childhood pneumonia etiology studies: 2000-2010

The Pneumonia Etiology Research for Child Health (PERCH) project is the largest multicountry etiology study of childhood pneumonia since the Board on Science and Technology in International Development studies of the 1980s. However, it is not the only recent or ongoing pneumonia etiology study, and even with seven sites, it cannot capture all epidemiologic settings in the developing world. Funding providers, researchers and policymakers rely on the best available evidence to strategically plan programs, new research directions and interventions. We aimed to describe the current landscape of recent pneumonia etiology studies in children under 5 years of age in the developed and developing world, as ascertained by a literature review of relevant studies with data since the year 2000 and a survey of researchers in the field of childhood pneumonia. We collected information on the study population, study design, case definitions, laboratory samples and methods and identified pathogens. A literature review identified 88 studies with child pneumonia etiology results. As of June 2010, our survey of researchers identified an additional 65 ongoing and recently completed child pneumonia etiology studies. This demonstrates the broad existing context into which the PERCH study must be placed. However, the landscape analysis also reveals a multiplicity of case definitions, levels of clinician involvement, facility types, specimen collection, and laboratory techniques. It reinforces the need for the standardization of methods and analyses for present and future pneumonia etiology studies in order to optimize their cumulative potential to accurately describe the microbial causes of childhood pneumonia.