RESUMO
Cross-reactions of gonococcal nucleic acid amplification tests (NAATs) with commensal Neisseria strains are well documented. Recent data now indicate that sequence-related false-negative results can occur in gonococcal NAATs, whereby target sequences either are absent or contain several mutations. In this study, a duplex Neisseria gonorrhoeae real-time polymerase chain reaction (PCR) (NGduplex) assay targeting the gonococcal porA pseudogene and multicopy opa genes was developed. The NGduplex was evaluated by testing 596 clinical specimens, including 292 urogenital specimens and 304 throat swab specimens. The results were compared with those obtained using a consensus reference standard comprising 3 monoplex real-time PCR assays. The results show that the NGduplex assay is highly suitable for routine screening for gonorrhea, providing an overall clinical sensitivity and specificity of 100% and 99.3%, respectively, for both urogenital and throat swab specimens. In addition, the 2-target system of the NGduplex assay decreases the potential for sequence-related false-negative results and can provide simultaneous confirmation of positive results.
Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Gonorreia/microbiologia , Neisseria gonorrhoeae/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Porinas/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , DNA Bacteriano/genética , Feminino , Genitália/microbiologia , Humanos , Masculino , Pessoa de Meia-Idade , Neisseria gonorrhoeae/genética , Faringe/microbiologia , Pseudogenes , Sensibilidade e EspecificidadeRESUMO
Polymerase chain reaction (PCR) is now recognized as a sensitive and specific method for detecting Plasmodium species in blood. In this study, we tested 279 blood samples, from patients with suspected malaria, by a PCR assay utilizing species-specific colorimetric detection, and compared the results to light microscopy. Overall, both assays were in agreement for 270 of the 279 specimens. P. vivax was detected in 131 (47.0%) specimens, P. falciparum in 64 (22.9%) specimens, P. ovale in 6 (2.1%) specimens, and P. malariae in 5 (1.8%) specimens. Both P. falciparum and P. vivax were detected in a further 10 (3.6%) specimens, and 54 (19.3%) specimens were negative by both assays. In the remaining nine specimens, microscopy either failed to detect the parasite or incorrectly identified the species present. In summary, the sensitivity, specificity and simplicity of the PCR assay makes it particularly suitable for use in a diagnostic laboratory.
Assuntos
Malária/sangue , Plasmodium/classificação , Reação em Cadeia da Polimerase/métodos , Animais , Austrália/epidemiologia , Sequência de Bases , Colorimetria , Sondas de DNA , Doenças Endêmicas , Feminino , Humanos , Malária/diagnóstico , Malária/epidemiologia , Masculino , Microscopia , Dados de Sequência Molecular , Plasmodium/isolamento & purificação , Valor Preditivo dos Testes , Estudos Prospectivos , Estudos de Amostragem , Sensibilidade e EspecificidadeRESUMO
The detection of Neisseria gonorrhoeae by the polymerase chain reaction (PCR) is now recognized as a sensitive and specific method of diagnosing infection by the organism. In this Study 152 urine specimens were examined for N. gonorrhoeae by a real-time PCR method using the LightCycler platform and results were compared to an "in-house" PCR assay using an ELISA-based detection method. N. gonorrhoeae DNA was detected in 29 (19%) specimens by LightCycler PCR (LC-PCR) and in 31 (20%) specimens by the "in house" PCR method. The LightCycler assay proved to be specific and 94% sensitive when compared to the "in house" PCR method. These features combined with the rapid turn-around time for results makes the LC-PCR particularly suitable for the detection of N. gonorrhoeae in a routine clinical laboratory.
