Development and application of real-time PCR assay for detection of mutations associated with macrolide resistance in Mycoplasma genitalium directly in clinical specimens

ABSTRACTKingella kingaeis a significant pediatric pathogen responsible for bone and joint infections, occult bacteremia, and endocarditis in early childhood. Past efforts to detect this bacterium using culture and broad-range 16S rRNA gene PCR assays from clinical specimens have proven unsatisfactory; therefore, by the late 2000s, these were gradually phased out to explore the benefits of specific real-time PCR tests targeting thegroELgene and the RTX locus ofK. kingae. However, recent studies showed that real-time PCR (RT-PCR) assays targeting theKingellasp. RTX locus that are currently available for the diagnosis ofK. kingaeinfection lack specificity because they could not distinguish betweenK. kingaeand the recently describedKingella negevensisspecies. Furthermore,in silicoanalysis of thegroELgene from a large collection of 45K. kingaestrains showed that primers and probes fromK. kingaegroEL-based RT-PCR assays display a few mismatches withK. kingae groELvariations that may result in decreased detection sensitivity, especially in paucibacillary clinical specimens. In order to provide an alternative togroEL- and RTX-targeting RT-PCR assays that may suffer from suboptimal specificity and sensitivity, aK. kingae-specific RT-PCR assay targeting the malate dehydrogenase (mdh) gene was developed for predicting no mismatch between primers and probe and 18 variants of theK. kingae mdhgene from 20 distinct sequence types ofK. kingae. This novelK. kingae-specific RT-PCR assay demonstrated high specificity and sensitivity and was successfully used to diagnoseK. kingaeinfections and carriage in 104 clinical specimens from children between 7 months and 7 years old.

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Evaluation of RealStar® Alpha Herpesvirus PCR Kit for Detection of HSV-1, HSV-2, and VZV in Clinical Specimens

BioMed Research International ◽

10.1155/2019/5715180 ◽

2019 ◽

Vol 2019 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Cyril C. Y. Yip ◽

Siddharth Sridhar ◽

Kit-Hang Leung ◽

Andrew K. W. Cheng ◽

Kwok-Hung Chan ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Test Performance ◽

Analytical Sensitivity ◽

Pcr Assay ◽

Clinical Specimens ◽

Varicella Zoster ◽

Simplex Virus ◽

Hsv 1

Several commercial PCR kits are available for detection of herpes simplex virus (HSV) and varicella zoster virus (VZV), but the test performance of one CE-marked in vitro diagnostic kit—RealStar® alpha Herpesvirus PCR Kit—has not been well studied. This study evaluated the performance of RealStar® alpha Herpesvirus PCR Kit 1.0 on the LightCycler® 480 Instrument II for detection and differentiation of HSV-1, HSV-2, and VZV in human clinical specimens. We evaluated the analytical sensitivity of the RealStar® and in-house multiplex real-time PCR assays using serial dilutions of nucleic acids extracted from clinical specimens. The analytical sensitivity of the RealStar® assay was 10, 32, and 100 copies/reaction for HSV-1, HSV-2, and VZV, respectively, which was slightly higher than that of the in-house multiplex real-time PCR assay. Reproducibility of the cycle threshold (Cp) values for each viral target was satisfactory with the intra- and interassay coefficient of variation values below 5% for both assays. One-hundred and fifty-three clinical specimens and 15 proficiency testing samples were used to evaluate the diagnostic performance of RealStar® alpha Herpesvirus PCR Kit against the in-house multiplex real-time PCR assay. The RealStar® assay showed 100% sensitivity and specificity when compared to the in-house assay. Cp values of the RealStar® and in-house assays showed excellent correlation. RealStar® alpha Herpesvirus PCR is a sensitive, specific, and reliable assay for the detection of HSV-1, HSV-2, and VZV, with less extensive verification requirements compared to a laboratory developed assay.

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Paradigm for diagnosing mycobacterial disease: direct detection and differentiation of Mycobacterium tuberculosis complex and non-tuberculous mycobacteria in clinical specimens using multiplex real-time PCR

Journal of Clinical Pathology ◽

10.1136/jclinpath-2017-204945 ◽

2018 ◽

Vol 71 (9) ◽

pp. 774-780 ◽

Cited By ~ 10

Author(s):

Jeong-Uk Kim ◽

Dae-Shick Ryu ◽

Choong-Hwan Cha ◽

Seon-Hee Park

Keyword(s):

Mycobacterium Tuberculosis ◽

Real Time ◽

Real Time Pcr ◽

Predictive Value ◽

Direct Detection ◽

Positive Culture ◽

Nucleic Acid Amplification ◽

Mycobacterial Disease ◽

Pcr Assay ◽

Clinical Specimens

AimsMycobacterium tuberculosis and non-tuberculous mycobacteria (NTM) are clinically different, and the rapid detection and differentiation of M. tuberculosis complex (MTBC) and NTM is crucial for patient management and infection control. Given the slow growth of most pathogenic mycobacteria, nucleic acid amplification assays are excellent tools for direct identification of mycobacteria in clinical specimens. Recently, a multiplex real-time PCR assay was developed that can directly detect 20 mycobacterial species in clinical specimens. Here, we evaluated the diagnostic performance of the assay for diagnosing mycobacterial disease under routine laboratory conditions.MethodsA total of 3334 specimens collected from 1437 patients suspected of tuberculosis infection were subjected to acid-fast bacilli staining, conventional culture and the multiplex real-time PCR assay. To evaluate the sensitivity and specificity of the assay, the overall diagnosis of tuberculosis was defined by positive culture plus medical history, and the 2007 American Thoracic Society and Infectious Disease Society of America diagnostic criteria for NTM disease were applied.ResultsThe sensitivity, specificity, positive predictive value and negative predictive value were 87.5%, 99.6%, 96.1% and 98.5%, respectively, for the detection of MTBC isolates and 53.3%, 99.9%, 95.2%, and 98.9%, respectively, for detecting NTM isolates.ConclusionsThus, the assay can correctly differentiate between MTBC and NTM isolates in clinical specimens and would be a useful tool for the rapid differentiation of tuberculosis and NTM disease, despite its limited sensitivity for the diagnosis of NTM disease.

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