Development and evaluation of a sensitive recombinase aided amplification assay for rapid detection of Vibrio parahaemolyticus.

Vibrio parahaemolyticus (V. parahaemolyticus) is a widely distributed pathogen in the coastal areas, which causes food poisoning and leads to gastroenteritis and sepsis. Therefore, developing a simple, sensitive, and rapid detection method for V. parahaemolyticus is a major concern globally. This study established a sensitive and rapid technique based on recombinase aided amplification (RAA) to detect V. parahaemolyticus. The RAA reaction was carried out successfully at 39 °C within 30 min. The sensitivity of the RAA assay was 101 copies/µL using the recombinant plasmid and 10-3 ng/µL using the V. parahaemolyticus strain. In addition, RAA directly detected 7 × 103 CFU/mL of simulated fecal samples and 0.1 CFU/mL after enrichment for 4 h. The sensitivity and specificity of the RAA assay using fecal and fish samples were 100% similar to that of the real-time PCR. We conclude that the RAA assay is an ideal screening method for detecting V. parahaemolyticus due to its rapidity, high accuracy, and simplicity in operation.

Estimation of the status of spiral ganglion neurons and Schwann cells in the auditory neural degeneration mouse using the auditory brainstem response.

CONCLUSION: The auditory brainstem response (ABR) wave I threshold, latency and amplitude are insensitive to spiral ganglion neurons (SGNs) degeneration, but are sensitive to the degeneration of Schwann cells and can estimate the status of Schwann cells in a neural degeneration mouse model. The thorough pre-operative ABR assessment would be helpful in predicting cochlear implant performance. OBJECTIVES: This study aimed in finding a non-invasive electrophysiological method to evaluate the status of the auditory nerve and the Schwann cells in sensorineural hearing loss (SNHL) and auditory neuropathy (AN) ears, and providing useful information for candidates screening and outcome prediction in cochlear implantation. METHODS: The frequency-specific acoustic ABR was recorded in mice. The immunohistochemical staining was performed to detect the SGNs and Schwann cells in mice cochlea. The correlations between ABR wave I metrics and SGNs, Schwann cells were investigated. RESULTS: In SNHL and AN mice cochlea, statistically significant correlations between ABR wave I thresholds, latencies and amplitudes at 8, 16, and 32 kHz and their corresponding SGNs densities were found only in wave I amplitude at 8 kHz. While the ABR wave I metrics at all three frequencies showed strong significant correlations with their corresponding Schwann cells densities.

Dose-dependent effects of ouabain on spiral ganglion neurons and Schwann cells in mouse cochlea.

OBJECTIVE: This study aimed in fully investigating the toxicities of ouabain to mouse cochlea and the related cellular environment, and providing an optimal animal model system for cell transplantation in the treatment of auditory neuropathy (AN) and sensorineural hearing loss (SNHL). METHODS: Different dosages of ouabain were applied to mouse round window. The auditory brainstem responses and distortion product otoacoustic emissions were used to evaluate the cochlear function. The immunohistochemical staining and cochlea surface preparation were performed to detect the spiral ganglion neurons (SGNs), Schwann cells and hair cells. RESULTS: Ouabain at the dosages of 0.5 mM, 1 mM and 3 mM selectively and permanently destroyed SGNs and their functions, while leaving the hair cells relatively intact. Ouabain at 3 mM resulted in the most severe SGNs loss and induced significant loss of Schwann cells started as early as 7 days and with further damages at 14 and 30 days after ouabain exposure. CONCLUSIONS: The application of ouabain to mouse round window induces damages of SGNs and Schwann cells in a dose- and time-dependent manner, this study established a reliable and accurate animal model system of AN and SNHL.

An acute gastroenteritis outbreak caused by GII.17 norovirus in Jiangsu Province, China.

Noroviruses are a common cause of acute gastroenteritis around the world; however, reports of outbreaks caused by GII.17 norovirus are rare. An outbreak caused by GII.17 norovirus in a senior high school in Wuxi, Jiangsu Province, China is reported here. An epidemiological investigation, pathogen detection, and case-control study were performed. Epidemiological data combined with the epidemic curve indicated that this outbreak was a point source type initially, followed by secondary transmission. The first case was identified as most likely the source of the outbreak. Risk analysis showed exposure to patients and sharing a communal water cooler to be associated with the spread of infection. Sequence analysis of GII-positive samples confirmed that the norovirus GII.17 variant was the etiological agent of this outbreak.

[A survey of levels of antibodies against influenza viruses in the population of Wuxi City].

OBJECTIVE: To investigate levels of antibodies against type A and type C influenza viruses and those against the 2009 H1N1 influenza A virus (before and after the 2009 H1N1 pandemic) among residents in Wuxi. To compare levels of antibodies against the 2009 H1N1 influenza virus (one year after the pandemic) in the unvaccinated population with those in the population who received vaccine. METHODS: Serum samples were collected from subjects (aged 1-60 years) during September 2008 to May 2009, and during September 2010 to January 2011. Also collected were serum samples from adults who had received vaccines for pandemic (H1N1) 2009 for one year. Antibody response to influenza viruses was measured using hemagglutination inhibition (HI) assay. Seropositivity rate, seroprotection rate and geometric mean titer (GMT) were compared for each age group during different periods. RESULTS: Before the outbreak of the 2009 H1N1 pandemic, seropositivity rate, seroprotection rate and GMT among the study subjects in were 2.86% (4/140), 0.71% (1/140) and 5.23, respectively. One year after the outbreak, seropositivity rate, seroprotection rate and GMT among the study subjects were 66.33%, 37.76% and 19.17, respectively. Among them, adult subjects showed 50.00% seropositivity rate, 19.44% seroprotection rate and 13.09 GMT, while adult subjects who had received vaccine for one year showed 61.36% seropositivity rate, 22.73% seroprotection rate and 14.14 GMT. No significant difference was observed between these two populations (P > 0.05 for all three indexes). Furthermore, before the outbreak of the 2009 H1N1 pandemic, levels of antibodies against seasonal influenza viruses among the study subjects were as follows: for H1N1 virus, seropositivity rate, seroprotection rate and GMT were 55.00%, 35.00% and 16.90, respectively; for H3N2 virus, seropositivity rate, seroprotection rate and GMT were 86.40%, 84.30% and 58.56, respectively. CONCLUSION: One year after the 2009 H1N1 influenza A virus had spread to Wuxi, the population levels of antibodies against this virus have approached those against seasonal influenza viruses, as reflected by seropositivity rates, seroproection rates and GMT. Moreover, considerable levels of antibodies against seasonal influenza viruses were observed in populations, indicating no seasonal influenza outbreak would occur recently.