ABSTRACT
【Objective】 To analyze the status of HBV infection in blood donors reactive to jointed NAT but non-reactive to primary discriminatory tests (NRR), so as to provide suggestions and data support for subsequent studies on NRR samples. 【Methods】 HCV RNA and HIV RNA repeat differential detection, HBV DNA viral load detection and HBV pgRNA copy volume detection were performed in the plasma of 60 blood donors with negative ELISA results in routine blood screening and NRR in NAT. HBsAg, HBsAb, HBcAb, HBeAg and HBeAb serological tests were performed on the NRR samples with positivity in HBV DNA viral load and HBV pgRNA virus copy detection, so as to analyze the serological infection status and occult hepatitis B (OBI) infection. 【Results】 The HCV RNA and HIV RNA repeat discrimination results of 60 NRR samples were negative. The quantitative detection results of HBV DNA in 60 NRR samples were positive in 9 cases (15%), and the HBV DNA concentration was less than 10IU/mL. Nine cases (15%) were positive for HBV pgRNA quantitative detection, and the virus copy volume ±SD was (289±58.25) copies/mL. Two NRR samples (3.33%) were HBV DNA positive and HBV pgRNA positive. Among the 9 HBV-DNA positive samples, the highest positive rate of HBcAb was 66.67%, and 7 (77.78%) of them were confirmed to be seropositive for OBI. Among the 9 HBV pgRNA positive samples, the copy amount of pgRNA in HBcAb positive samples was slightly higher than that in negative samples, while the copy amount of pgRNA in HBsAb and HBeAb positive samples was lower than that in corresponding negative samples. In recent 6 years, the proportion of NRR samples in the single NAT system of the center fluctuated from 0.09% to 0.13%. 【Conclusion】 HBV DNA and HBV pgRNA exist in NRR samples. HBV DNA and/or HBV pgRNA positive samples can be detected in the relevant serological infectious markers. NRR samples have a certain potential risk of OBI infection. HBV DNA detection plus HBV pgRNA can better confirm the status of virus infection in NRR and improve the safety of blood transfusion.
ABSTRACT
Objective To develop a rapid PCR fingerprinting for discriminating between Candida albicans and Candida dubliniensis isolates. Methods Genomic DNA purified from the two species was amplified by single primer PCR. Oligonucleotide of the minisatellite-specific core sequence of the wild-type phage M13 (5′-GAGGGTGGCGGTTCT-3′) was used as primer and the amplified products were analyzed by gel electrophoresis and microfluidic DNA chip assays. Results Of 17 candida isolates, the PCR fingerprinting generated five strain-specific bands for C. albicans and C. dubliniensis respectively, allowing identification to species level between them. The other bands were minor different in their species. By microfluidic DNA chip, the DNA fragments in size of amplified products for the C. dubliniensis were 960,1177,1297,1495,1797 bp and for the C. albicans 653,1323,1531,2021,2875 bp. Conclusions C. albicans and C. dubliniensis have distinguishable pattern by PCR fingerprinting using the single primer. The microfluidic DNA chip is proposed here as a simple, rapid and highly reproducible tool, especially for the epidemiological investigation.