5 research outputs found
Clinical Usefulness of Multiplex PCR Lateral Flow in MRSA Detection: A Novel, Rapid Genetic Testing Method
Methicillin-resistant Staphylococcus aureus (MRSA) with exogenous cassette DNA containing the methicillin-resistant gene mecA (SCCmec) poses a problem as a drug-resistant bacterium responsible for hospital- and community-acquired infections. The frequency of MRSA detection has recently been increasing rapidly in Japan, and SCCmec has also been classified more diversely into types I–V. A rapid test is essential for early diagnosis and treatment of MRSA infections, but detection by conventional methods requires at least two days. The newly developed multiplex PCR lateral flow method allows specific amplification of femA to detect S. aureus, mecA to detect SCCmec, and kdpC to detect SCCmec type II; moreover, PCR products can be evaluated visually in about 3 h. In the present study, we developed a PCR lateral flow method for MRSA using this method and investigated its clinical usefulness in the detection of MRSA. The results showed a diagnostic concordance rate of 91.7% for MRSA and methicillin-susceptible S. aureus between bacteriological examination and PCR lateral flow, and a high level of specificity in PCR lateral flow. In addition, a higher detection rate for S. aureus using the same sample was observed for PCR lateral flow (70.2%) than for bacteriological tests (48.6%). The above results show that PCR lateral flow for MRSA detection has high sensitivity, specificity, and speed, and its clinical application as a method for early diagnosis of MRSA infections appears to be feasible
Correlation among Singlet-Oxygen Quenching, Free-Radical Scavenging, and Excited-State Intramolecular-Proton-Transfer Activities in Hydroxyflavones, Anthocyanidins, and 1‑Hydroxyanthraquinones
Singlet-oxygen
(<sup>1</sup>O<sub>2</sub>) quenching, free-radical
scavenging, and excited-state intramolecular proton-transfer (ESIPT)
activities of hydroxyflavones, anthocyanidins, and 1-hydroxyanthraquinones
were studied by means of laser, stopped-flow, and steady-state spectroscopies.
In hydroxyflavones and anthocyanidins, the <sup>1</sup>O<sub>2</sub> quenching activity positively correlates to the free-radical scavenging
activity. The reason for this correlation can be understood by considering
that an early step of each reaction involves electron transfer from
the unfused phenyl ring (B-ring), which is singly bonded to the bicyclic
chromen or chromenylium moiety (A- and C-rings). Substitution of an
electron-donating OH group at B-ring enhances the electron transfer
leading to activation of the <sup>1</sup>O<sub>2</sub> quenching and
free-radical scavenging. In 3-hydroxyflavones, the OH substitution
at B-ring reduces the activity of ESIPT within C-ring, which can be
explained in terms of the nodal-plane model. As a result, the <sup>1</sup>O<sub>2</sub> quenching and free-radical scavenging activities
negatively correlate to the ESIPT activity. A catechol structure at
B-ring is another factor that enhances the free-radical scavenging
in hydroxyflavones. In contrast to these hydroxyflavones, 1-hydroxyanthraquinones
having an electron-donating OH substituent adjacent to the O–H---OC
moiety susceptible to ESIPT do not show a simple correlation between
their <sup>1</sup>O<sub>2</sub> quenching and ESIPT activities, because
the OH substitution modulates these reactions