Development and evaluation of a real-time method for testing human enteroviruses and coxsackievirus A16

Dual carminic acid/hemin-marked DNA probes for simultaneously detecting CV-A16 and EV-A71 based on the mechanism of dimer to monomer transition

This study aimed to prepare two hairpin-structure DNA probes by conjugating carminic acid (CA) or hemin into two ends of specific genes of coxsackievirus A16 (CV-A16) and enterovirus A71 (EV-A71) (probe_CV-A16-CA and probe_EV-A71-hemin). Then, probe_CV-A16-CA and probe_EV-A71-hemin as the signal molecules were adsorbed onto NH₂-MIL-53 (Al) (MOF). Based on these biocomposites, an electrochemical biosensor with dual-signal outputs for simultaneous assay of CV-A16 and EV-A71 was constructed. The stem-loops of probes switched both CA and hemin monomer to dimer, reducing the electrical activity of both CA and hemin. Subsequently, the target-induced opening of the stem-loop switched both CA and hemin dimers to monomers, resulting in two nonoverlapping increasing electrical signals. This sensitively reflected the concentration of target_CV-A16 and target_EV-A17 ranging from 10^-10 to 10^-15 M with a detection limit of 0.19 and 0.24 fM. This strategy was mainly applied to the simultaneous determination of target_CV-A16 and target_EV-A17 in 100% serum with satisfactory results. The MOF combined with the high loading capacity broke through the intrinsic limitation on sensitivity using the traditional methods. An increase of three orders of magnitude was observed. This study involved simple one-step detection, and only a simple replacement of a gene could trigger its potential in clinical and diagnostic applications.

Mycoplasma genitalium incidence, treatment failure, and resistance: a retrospective survey of men of infertile couples from a hospital in China

BACKGROUND

Mycoplasma genitalium infection is significantly associated with an increased risk of male infertility. To date, few large M. genitalium studies have been conducted in China.

OBJECTIVE

This study aimed to estimate the M. genitalium incidence and treatment failure and to provide information regarding the resistance of M. genitalium to macrolide and tetracycline antibiotics among men of infertile couples in China.

MATERIALS AND METHODS

This study was performed as a retrospective survey of seminal and meatus urinarius secreta specimens of 30,094 men of infertile couples collected and used for microbiological tests for the evaluation of genital tract infections (Mycoplasma genitalium, Chlamydia trachomatis, and Neisseria gonorrhoeae) between October 2016 and December 2017. Mycoplasma genitalium RNA was detected using novel simultaneous amplification testing. Macrolide and tetracycline resistance screening was introduced using polymerase chain reaction (PCR) and Sanger sequencing.

RESULTS

The incidence of M. genitalium was 2.49% (749 of 30,094; 95% confidence interval (CI), 2.31-2.66%). After antibiotic treatment, the mean values of semen parameters increased from those measured before treatment. The overall incidence of treatment failure was 17.56% (82/467; 95% CI, 14.10%-21.02%) (112-26-4 = 82), irrespective of the drug used. Resistance to macrolide and tetracycline antibiotics was detected in 58 samples (58/60, 96.67%; 95% CI, 91.99-101.34%) and 27 samples (27/60, 45.00%; 95% CI, 32.04-57.96%), respectively.

CONCLUSIONS

Although the M. genitalium incidence was relatively low, the detection of macrolide antibiotic resistance in >96.67% of the treatment failure samples most likely explained the high azithromycin treatment failure rate (73/195, 37.44%) in our study. These findings indicate the need to provide resistance testing and to reappraise the recommended antimicrobial options in China.

Comparison of rRNA-based and DNA-based nucleic acid amplifications for detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Ureaplasma urealyticum in urogenital swabs

Background

Nucleic acid amplification tests (NAAT) are well-accepted in diagnosis and surveillance of sexually infectious pathogens worldwide. However, performance differences between a RNA-based NAAT and DNA-based NAAT are rarely reported. This study compares the performances of the RNA-based SAT (simultaneous amplification and testing) assay and the DNA-based quantitative real-time polymerase chain reaction (qPCR) assay.

Methods

A total of 123 urogenital swabs were collected from outpatients with suspected genital infections in our hospital. Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Ureaplasma urealyticum (UU) in these swabs were simultaneously tested by SAT and qPCR. Any swabs were positive in the qPCR assay were further verified by following cloning and sequencing. All statistical analysis was performed using the SPSS software.

Results

When the concentrations of CT, NG, or UU were more than 1 × 10³ copies/ml, 100% agreements between SAT and qPCR were observed regardless of the pathogen. No discrepancy was found. However, the sensitivity of SAT is significantly higher than qPCR in samples with concentration less than 1 × 10³ copies/ml. When tested by SAT and qPCR, 57.14 and 28.57% were positive for CT, 46.15% and 0 were positive for NG, 80% and 0 were positive for UU, respectively.

Conclusions

The SAT assay has better agreements and higher sensitivities when compared with the qPCR assay, and thus could be a better choice for screening, diagnosis, and surveillance of sexually transmitted diseases, especially for CT and NG.

Understanding the epidemiological characteristics of EV71 and CVA16 infection to aid the diagnosis and treatment of hand, foot, and mouth disease

Hand, foot, and mouth disease (HFMD) have been recognized over the past several years as a highly infectious disease in children. Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the two major causative agents. The objective of this study was to determine the optimal time and method of HFMD detection, explore the seroconversion of IgM and IgG antibodies, and examine the response of neutralizing antibody (NtAb) to EV71 or CVA16. Between January 2016 and December 2017, a total of 460 patients, diagnosed with HFMD based on clinical symptoms and hospitalized in the First Hospital of Jilin University, were recruited for the study. At approximately 72 hours post illness onset, we observed that the positive rate of both IgM and real-time polymerase chain reaction detection of EV71 or CVA16 was the highest, this could be considered as the optimal detection time for clinical diagnosis. During the initial 0 -96 hours, the relative highest IgM and the relative lowest IgG antibody levels were observed. The NtAb titers to EV71 and CVA16 also gradually increased with time, showing a positive correlation with age, and being the predominant factor during the hospitalized days. Thus, our study provides important information for the clinical diagnosis and treatment of HFMD.

Portable Infrared Isothermal PCR Platform for Multiple Sexually Transmitted Diseases Strand Detection

Rapid and portable PCR detection is essential for screening sexually transmitted infections regularly. We developed an infrared mediated RNA isothermal RT-PCR (IR-MERIT PCR) platform and its compatible multichamber microfluidic chip for simultaneous amplification and testing (SAT) detection. This microfluidic chip integrates RNA extraction, micropump, and multitarget detection function onto the same chip. By utilizing IR-light-emitting diode (LED) as heat source, this platform can fulfill isothermal amplification within 70 min.

Prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Ureaplasma urealyticum infections using a novel isothermal simultaneous RNA amplification testing method in infertile males

Background

The purpose of this study was to evaluate the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Ureaplasma urealyticum infections in infertile men that consulted our outpatient departments using a novel simultaneous amplification testing (SAT) that is RNA-detection based. The possible impact of C. trachomatis, N. gonorrhoeae, M. genitalium and U. urealyticum infections on semen parameters was also noted in the present study.

Methods

A total of 2607 males that were diagnosed with infertility were included in this study. C. trachomatis, N. gonorrhoeae, M. genitalium and U. urealyticum infections were detected in the urine samples using SAT method. Related data, including semen parameters and age as well as C. trachomatis, N. gonorrhoeae, M. genitalium and U. urealyticum infections were collected and analyzed.

Results

A total of 51 and 1418 urine samples were found positive for M. genitalium RNA and U. urealyticum RNA, respectively, while the prevalence of C. trachomatis and N. gonorrhoeae was relatively lower. Men with positive M. genitalium RNA and U. urealyticum RNA had higher sperm DNA fragmentation index (DFI) while the comparisons of other semen parameters yielded nonsignificant results between the RNA positive and negative group. A multivariate linear regression analysis revealed that U. urealyticum and M. genitalium infections posed significant factors of DFI (adjusted R² = 46.2%).

Conclusions

Our study suggested a relative high prevalence of U. urealyticum and M. genitalium infection based on this novel SAT detection method. U. urealyticum and M. genitalium infection could possibly impair male fertility potential through promoting sperm DNA damage.