Application of real-time simultaneous amplification and testing method to accurately and rapidly detect extra-pulmonary tuberculosis

Characteristics of common pathogens of urogenital tract among outpatients in Shanghai, China from 2016 to 2021

Background

Ureaplasma urealyticum, Chlamydia trachomatis, and Neisseria gonorrhoeae are the prevalent causes of several genital diseases worldwide; however, their characteristics in different genders have not been well documented in Shanghai. The aim of this study is to describe the prevalence of common pathogens among outpatients, considering variations by gender and age.

Methods

From January 1, 2016, to December 31, 2021, the urogenital swabs of 16216 outpatients aged 3-95 years from two general hospitals in Shanghai were collected. All participants' swabs were investigated for U. urealyticum, C. trachomatis, and N. gonorrhoeae by isothermal RNA-based simultaneous amplification and testing. The basic information of all participants was also recorded, including age and gender. The chi-square test was used to compare the prevalence between different genders, age groups, and infection patterns.

Results

There were 5,744 patients (35.42%) with positive samples whose ages ranged from 7 to 80 years (33.23 ± 8.63 years), and 62.14% of them were women. The most common pathogen detected was U. urealyticum (85.08%). The highest prevalence rate of all three pathogens was found in patients aged ≤ 20 years (40.53%, 95% confidence intervals [CI]: 33.80%-47.63%). The prevalent rate of U. urealyticum was higher in men (33.36%, 95% CI: 32.19%-34.55%). The overall prevalence rates of U. urealyticum, C. trachomatis, and N. gonorrhoeae were 30.14% (95% CI: 29.44%-30.85%), 6.00% (95% CI: 5.64%-6.38%), and 2.10% (95% CI: 1.89%-2.33%).

Conclusions

Ureaplasma urealyticum was the most prevalent pathogen in the population, and its prevalence decreased with age. Young men aged ≤ 20 years were more frequently infected. Regular screening for sexually transmitted pathogens in different genders and age groups are warranted, particularly in young men.

Application value of antibody titres and RNA detection in the early prediction of Mycoplasma pneumoniae pneumonia in children: a retrospective study

BACKGROUND

Children with Mycoplasma pneumoniae pneumonia (MPP) are prone to a missed diagnosis at the early stages of the disease, which greatly affects the prognosis of children. In this study, the application value of Mycoplasma pneumoniae (MP) antibody titres and RNA detection for diagnosing MP infection in children with community-acquired pneumonia (CAP) was evaluated. The present study aimed to seek appropriate detection methods and strategies for early rapid diagnosis in children with MPP.

METHODS

A retrospective study was conducted on 563 paediatric patients aged 1 month to 15 years with CAP who were admitted to Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science and Technology between July 2021 and February 2022. In all patients, throat swabs were collected for MP-RNA detection (simultaneous amplification and testing, SAT), and paired serum samples were collected for MP total antibody detection (particle agglutination, PA).

RESULTS

The classification as MPP or non-MPP was based on clinical diagnosis, serum MP antibody titre, and clinical or laboratory evidence of infection by other pathogen(s). Among the 563 patients with pneumonia, 187 patients were in the MPP group, and 376 patients were in the non-MPP group. The Kappa values between the particle agglutination test at different titres (1:80, 1:160) and MP-RNA detection were 0.612 and 0.660 (P<0.01), and the consistency of the three methods was acceptable. When the single screening method was used, MP-RNA had the highest sensitivity (93.05%), while PA (1:160) had the highest specificity (100%). PA (1:80), with an area under the curve (AUC) of 0.822, was better than PA (1:160), with an AUC of 0.783, and there was a significant difference. When the combined screening methods were used, the AUC of MP-RNA parallel PA (1:160) was significantly higher than that of titres (1:80) (z=-4.906, P < 0.01). Except for MP-80, the efficacy of the other three test methods in females was slightly better than that in males. Among the differences in age distribution, PA (1:80) was slightly less effective in the 13-72 months age group than at other ages, and MP-RNA parallel PA (1:160) was slightly better than the younger age group (≤ 36 m). In the older age group (> 36 m), PA (1:160) was just the opposite, while MP-RNA was slightly better than other age groups in the 13-72 months age group.

CONCLUSIONS

For the diagnosis of MPP in children at the early of the disease, the antibody titre (1:160) parallel MP-RNA should be given preference, and then the disease should be further classified according to the antibody titre level and the age of the child. The combined application of the two detection methods could complement each other and strengthen the advantages, providing reliable laboratory evidence for the clinical diagnosis and timely treatment of MPP. When using the PA method alone to provide a reference standard to clarify MP infection, the differential diagnosis ability of 1:80 for MPP is better than 1:160, especially for children younger than 36 months.

Clinical utility of tuberculosis RNA in the rapid diagnosis of bone and joint tuberculosis

OBJECTIVES

To evaluate the diagnostic accuracy of tuberculosis RNA (TB-RNA) for the rapid diagnosis of bone and joint tuberculosis (BJTB).

METHODS

We conducted a retrospective study to evaluate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of TB-RNA and acid-fast bacillus (AFB) smear against the final clinical diagnosis.

RESULTS

A total of 268 patients were included. The overall sensitivity, specificity, PPV, NPV, and AUC of AFB smear for BJTB were 0.7%, 100.0%, 100.0%, 49.3%, and 0.50, respectively, whereas those of TB-RNA were 59.6%, 100.0%, 100.0%, 70.6%, and 0.80, respectively; for cases of confirmed (culture-positive) BJTB, these values were 82.8%, 99.4%, 99.7%, 89.2%, and 0.91, respectively.

CONCLUSIONS

The diagnostic accuracy of TB-RNA in the rapid diagnosis of BJTB was relatively good, especially in culture-positive BJTB. The use of TB-RNA could be an effective technique for the rapid diagnosis of BJTB.

Application of Mycobacterium tuberculosis RNA for the Rapid Diagnosis of Lymph Node Tuberculosis Using Different Specimens

Purpose

To evaluate the accuracy of Mycobacterium tuberculosis (MTB)-RNA in the rapid diagnosis of lymph node tuberculosis (LNTB). Moreover, the difference in the diagnostic accuracy of MTB-RNA using different specimens was determined.

Methods

We included patients with suspected LNTB who met the inclusion criteria and retrospectively analyzed their clinical data. The sensitivity, specificity, positive-predictive value (PPV), negative-predictive value (NPV), and area under the curve (AUC) of MTB-RNA and culture were calculated and its diagnostic accuracy for LNTB was evaluated in comparison with the final clinical diagnosis.

Results

Overall, 285 patients were included in the study. The overall sensitivity, specificity, PPV, NPV, and AUC of MTB-RNA were 40.6%, 100.0%, 100.0%, 17.0%, and 0.70, respectively. These values were 30.8%, 100.0%, 100.0%, 16.0%, and 0.65, respectively, for tissue specimens; 34.2%, 100.0%, 100.0%, 24.6%, and 0.67, respectively, for puncture specimens; and 57.14%, 100.0%, 100.0%, 5.3%, and 0.79, respectively, for pus specimens. These values of culture were 24.4%, 100.0%, 100.0%, 13.9%, and 0.62, respectively, for all specimens; 17.6%, 100.0%, 100.0%, 13.8%, and 0.59, respectively, for tissue specimens; 25.3%, 100.0%, 100.0%, 22.4%, and 0.63, respectively, for puncture specimens; and 31.0%, 100.0%, 100.0%, 3.3%, and 0.65, respectively, for pus specimens.

Conclusion

The diagnostic efficacy of MTB-RNA for the rapid diagnosis of LNTB was moderate, but its sensitivity was low. The lymph node pus specimens were the most sensitive for MTB-RNA testing, followed by puncture specimens; tissues were the least sensitive. Pus specimens should be preferably obtained in case only this test is to be used for diagnosis.

Comparing Mycobacterium tuberculosis RNA Accuracy in Various Respiratory Specimens for the Rapid Diagnosis of Pulmonary Tuberculosis

Objective

To evaluate the rapid diagnostic accuracy of Mycobacterium tuberculosis RNA (TB-RNA) for pulmonary tuberculosis (PTB) in a large patient sample and to evaluate the difference in TB-RNA diagnostic accuracy in various respiratory specimens.

Methods

Patient medical records were retrospectively reviewed to determine the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) of the acid-fast bacillus (AFB) smear and TB-RNA to evaluate their diagnostic accuracy against final clinical diagnosis.

Results

Of the 2336 patients ultimately included, 1123 provided 1 sputum specimen each and 1213 provided 1 bronchoalveolar lavage fluid (BALF) specimen each. The overall sensitivity, specificity, PPV, NPV, and AUC of the AFB smear were 36.2%, 86.4%, 90.6%, 27.3%, and 0.61, respectively. The overall sensitivity, specificity, PPV, NPV, and AUC of TB-RNA for the rapid detection of PTB were 57.4%, 99.4%, 99.7%, 39.3%, and 0.78, respectively. When sputum and BALF specimens were used for AFB smear testing, the sensitivity, specificity, PPV, NPV, and AUC of the AFB smear were 44.5%, 81.5%, 87.5%, 33.5%, and 0.63; and 29.2%, 92.7%, 94.8%, 22.5%, and 0.61, respectively. The sensitivity, specificity, PPV, NPV, and AUC of TB-RNA for the rapid detection of PTB using sputum were 49.6%, 99.3%, 99.5%, 40.4%, and 0.74, respectively; whereas those of TB-RNA determined using BALF were 63.9%, 99.5%, 99.8%, 38.0%, and 0.82, respectively.

Conclusion

The diagnostic accuracy of TB-RNA for PTB was moderate and considerably better than that of the AFB smear. The diagnostic accuracy of TB-RNA for various respiratory specimens differed; the diagnostic accuracy of TB-RNA for BALF specimens was substantially better than that for sputum samples, and BALF specimens were more suitable for TB-RNA.