Evaluation of a commercial latex agglutination test for detecting rotavirus A and human adenovirus in children's stool specimens

Development of a Molecular Beacon-Based Genosensor for Detection of Human Rotavirus A

The rotavirus-led fatal infantile gastroenteritis in the globe demands a portable, specific, and low-cost diagnostic tool for its timely detection and effective surveillance in a mass population. Consequently, the design and development of an advanced biosensing technique for its detection is of paramount importance. A highly conserved 23-nucleotide sequence, 5' GCTAGGGATAAGATTGTTGAAGG 3', was identified by a human rotavirus A VP6 gene sequence analysis and designated as the target. A molecular beacon of 33 nucleotides was designed with the sequence 5'[Fluorescein] ATAGTCCTTCAACAATCTTATCCCTAGCACTAT[Dabcyl]3', incorporating stem and loop regions. Secondary and tertiary structure characterizations confirmed the desired stem-loop structure without internal secondary structures. The thermal stability of the molecular beacon-target complex was studied using a temperature vs. Gibbs free energy change plot, melting curve analysis based on absorbance vs. temperature, and an experimental fluorescence resonance energy transfer melting assay. The melting temperature of the molecular beacon-target complex was experimentally determined to be 62 °C. The spectral analysis showed fluorescence restoration in the presence of the synthetic VP6 target. The assay conditions were optimized with an excitation wavelength of 470 nm and a 10-min incubation time. The assay demonstrated a linear correlation between fluorescence intensity restoration and target concentration, with a limit of detection of 18.8 nM. Interference studies with single mismatch, double mismatch, and scrambled targets revealed that the molecular beacon has strong specificity for the VP6 target, effectively discriminating against non-target sequences. This work demonstrates the molecular beacon's potential as a sensitive and specific tool for detecting rotavirus A VP6 gene, with promising applications in diagnostic assays for the rotavirus disease management.

New latex agglutination assay for the determination of lactoferrin in human milk

BACKGROUND

Lactoferrin (LF) in human milk has various biological properties and contributes to the prevention of preterm birth complications. Enzyme-linked immunosorbent assay (ELISA) is one of the most commonly used methods to measure LF in human milk, but this method is time-consuming and laborious. In Japanese human milk banks, the concentration of LF in donor human milk (DHM) is measured routinely. Here, we reported a rapid, simple, and accurate method for determining LF in human milk using a new reagent based on a latex agglutination assay.

METHODS

We obtained 208 human milk pools from 148 mothers, and samples were collected before and after Holder pasteurization. Milk samples were diluted 100- or 200-fold and LF concentrations were measured by a latex agglutination assay using an automated analyzer. The reagent was validated in terms of repeatability, linearity, detection limit, recovery, and comparison with ELISA.

RESULTS

The coefficient of variation (CV) for intra-assay precision ranged from 0.6 to 5.0% in human milk with high, medium, and low LF concentrations. The linearity was also tested by serial sample dilution and was confirmed up to 16 µg/mL with a detection limit of 0.2 µg/mL. The recovery rates in a spiked recovery test were ranged from 90 to 120% at high, medium, and low concentrations of LF. Furthermore, a strong correlation was observed between LF levels determined by the latex agglutination assay and ELISA (r = 0.978, p < 0.001, n = 255). The regression equation was y = 0.991x + 0.545 (r2 = 0.974, p < 0.001). Compared with ELISA, the latex agglutination assay reduces the measurement time by 160 min and the cost by 55%.

CONCLUSIONS

The latex agglutination assay used to determine LF in human milk is rapid, simple, and accurate enough to be used routinely. Its use may contribute to the quick and easy provision of appropriate DHM to preterm infants.

Viral diarrheas - newer advances in diagnosis and management

PURPOSE OF REVIEW

Viruses are the most common etiological agents of diarrhea in children. Despite rotavirus vaccine introduction, rotavirus remains as the leading cause of death globally, followed by norovirus, which represents a diagnostic challenge. Here, we describe new advances in the diagnosis and management of viral diarrheas.

RECENT FINDINGS

Although immunoassays are widely used for their fast turnaround time and low cost, molecular techniques have become the most reliable diagnostic method due to their high sensitivity and capacity to analyze multiple pathogens in gastrointestinal panels. Isothermal nucleic acid amplification assays (LAMP and RPA) are promising techniques since they do not require sophisticated equipment and can be used as point-of-care testing. CRISPR/Cas nucleic acid detection systems are new diagnostic methods with great potential. Several recent published articles describe the role of human intestinal enteroids to characterize norovirus infection, to test new drugs, and for vaccine development. The interaction between the human gut microbiota and gastrointestinal viral infections has been extensively reviewed and offers some innovative mechanisms for therapeutic and preventive measures.

SUMMARY

Although important advances have been made, more research is needed to address remaining challenges and further improve diagnostic capabilities and better management strategies for this critical infectious disease.

Effect of COVID-19 protective measures on the epidemiology characteristics of rotavirus, adenovirus, and coinfections among pediatric patients with acute gastroenteritis in Hangzhou, China

Human rotavirus (RV) and adenovirus (AdV) have been recognized as common enteric viruses associated with viral acute gastroenteritis (AGE) in children aged<5 years. However, with the transmission of coronavirus disease 2019 (COVID-19) has been suppressed due to various aggressive and effective anti-epidemic measures, the prevalence of other viruses has also been affected. Therefore, this study aimed to investigate the impact of COVID-19 on the epidemiological characterization of RV, AdV, and coinfections among children with AGE in a hospital in Hangzhou from 2019 to 2023. The overall changes, seasonal distribution, and age distribution of enteroviruses were analyzed based on 5 years of records. All data were analyzed using SPSS 27.0. A total of 102,049 samples were analyzed from January 2019 to August 2023, and among them 15,911 (15.59%) were positive specimens, 11,646 (11.41%) were RV-positive, 4,057 (3.98%) were AdV-positive, and 208 (0.20%) were coinfection. The positive rate among males was 15.54%, while among females was 15.66% with a male-to-female ratio of 1.42:1. There was no significant difference in the positive rates of enterovirus infection between males and females. Significant associations were found between the month group and RV/AdV infection, with RV detection peaking in winter (74.18%) and early spring (29.22%), while AdV has a high prevalence in summer (16.03%) and spring (12.71%). The age group was also found to be significantly associated with RV/AdV infection, with RV being most prevalent in the 1-3-year-old age group (16.99%), while AdV was highest in the 3-5-year-old age group (8.10%).IMPORTANCEThis study highlights the epidemiological changes of rotavirus (RV), adenovirus (AdV), and coinfections in children with acute gastroenteritis (AGE) before, during, and after coronavirus disease 2019 (COVID-19) periods. There was a highly statistically significant difference in the positive rates of RV-positive, AdV-positive, and coinfection (P < 0.001), indicating that RV remains the main pathogen causing AGE. It emphasizes the importance of continuous surveillance of RV and AdV at both local and global levels. Regular surveillance of prevalent rotavirus strains will facilitate the development of new inactivated rotavirus vaccines and aid in disease prevention and control.

Nonpharmaceutical interventions against the COVID-19 pandemic significantly decreased the spread of enterovirus in children

BACKGROUND

Precise prevention and control measures have been adopted to impede the transmission of COVID-19 in China. This study was performed to investigate the effect of protective measures on gastrointestinal infection in children during the COVID-19 pandemic.

METHODS

The data on the rotavirus and adenovirus antigen tests were collected in outpatient children due to gastroenteritis from January 1, 2019, to December 31, 2020, at the Children's Hospital of Zhejiang University School of Medicine. According to age and month distribution, the positive number and rate of rotavirus and adenovirus in 2020 were compared with 2019.

RESULTS

A 3.8-fold and 4-fold reduction in the number of rotavirus- and adenovirus-positive patients in 2020 were found, respectively. The overall positive rate of rotavirus and adenovirus infection was drastically decreased in 2020 (rotavirus 2020: 18.18% vs 2019: 9.75%, P < 0.001; adenovirus 2020: 3.13% vs 2019: 1.58%, P < 0.001). The proportions of rotavirus and adenovirus in all age groups in 2020 decreased compared with those in 2019. The highest frequency of rotavirus infection occurred among children aged 1-3 years both in 2019 and 2020 (2019: 27.95% vs 2020: 17.19%, P < 0.001), while adenovirus infection was detected in children aged 3-5 years, which had the highest percent positivity (2019: 8.19% vs 2020: 4.46%; P < 0.001). An obvious peak prevalence of rotavirus incidence was found during December-April, and the percent positivity of rotavirus significantly decreased in 2020 (December 2019: 24.26% vs 2020: 8.44%, P < 0.001; January 2019: 40.67% vs 2020: 38.18%, P < 0.05; February 2019: 40.73% vs 2020: 15.04%, P < 0.001; March 2019: 31.47% vs 2020: 7.88%, P < 0.001; April 2019: 15.52% vs 2020: 4.78%, P < 0.001). The positive rate of adenovirus distributed throughout 2019 was 1.91%-4.86%, while the percent positivity during 2020 in the same period was much lower (0.00%-3.58%).

CONCLUSIONS

Our results confirmed that the preventive and control measures adopted during the COVID-19 pandemic and the collateral benefit of these interventions have significantly decreased the transmission of rotavirus or adenovirus. This article is protected by copyright. All rights reserved.

Multiplex detection of eight different viral enteropathogens in clinical samples, combining RT-PCR technology with melting curve analysis

Background

Early and accurate identification of infection viruses among children can benefit the personalized medical treatment and management, and reduce the future occurrence of serious symptoms. Thus, it is critical to develop a high-throughput multiplex real-time RT-PCR method to improve the accuracy and efficiency in routine clinical lab tests.

Methods

We developed a real time RT-PCR combined with melting curve analysis (RRCMC) method for simultaneous detection of rotavirus A, B, C, norovirus GI and GII, adenovirus, astrovirus and sapovirus.

Results

Stool samples were collected from 160 children with acute diarrhea and tested by RRCMC assay. A total of 71 patients were tested positive with norovirus, adenovirus or rotavirus. The RRCMC assay has high specificity. There is no internal cross-reaction among the 8 diarrhea viruses and no cross-reaction of other commonly intestinal pathogens and human genome. The limit detection was ranged from 1 × 10² to 1 × 10⁵ nucleic acid copies/ml for each diarrhea virus.

Conclusion

The RRCMC method is a suitable rapid clinical test for infectious viruses, with the advantages of high-throughput, low cost, high sensitivity and specificity.

Rotavirus and adenovirus infections in children during COVID-19 outbreak in Hangzhou, China

BACKGROUND

This study aims to investigate the impact of protective measures and isolation on intestinal infection in children before and after COVID-19 outbreak in Hangzhou, China.

METHODS

Data on outpatient visits, intestinal infection visits, and tests of adenovirus or rotavirus from electronic healthcare records were extracted in Children's Hospital of Zhejiang University School of Medicine during the COVID-19 outbreak (January-December, 2020), and be compared with those in 2019 during the same period.

RESULTS

We found that pediatric outpatient visits, patients with intestinal infection and its proportion from January to December of 2020 were significantly less than that in the same period of 2019. Furthermore, the numbers of outpatient visits and patients with intestinal infection were the lowest in February and elevated slowly from March to December in 2020. We also found significantly decreased number of completed tests for intestinal viruses, positive cases of adenovirus and rotavirus, positive rate of rotavirus during January-December, 2020. The positive rates of adenovirus from March to September and December of 2020 were significantly lower than the levels of the same period in 2019. The positive rate of rotavirus and adenovirus in all age groups in 2020 is lower than the level of all age groups in 2019.

CONCLUSIONS

The outpatient visits and intestinal, rotavirus and adenovirus infections in children significantly decreased during COVID-19 outbreak. Adequate protective measures and isolation in children may help to prevent intestinal virus infections in children.

Aptamer-based approaches for the detection of waterborne pathogens

Waterborne ailments pose a serious threat to public health and are a huge economic burden. Lack of hygiene in drinking and recreational water is the chief source of microbial pathogens in developing countries. Poor water quality and sanitation account for more than 3.4 million deaths a year worldwide. This has urged authorities and researchers to explore different avenues of pathogen detection. There is a growing demand for rapid and reliable sensor technologies, in particular those that can detect in situ and perform in harsh conditions. Some of the major waterborne pathogens include Vibrio cholerae, Leptospira interrogans, Campylobacter jejuni, Shigella spp., enterotoxigenic Escherichia coli, Clostridium difficile, Cryptosporidium parvum, Entamoeba histolytica, and Hepatitis A virus. While conventional methods of pathogen detection like serodiagnosis and microbiological methods have been superseded by nucleic acid amplification methods, there is still potential for improvement. This review provides an insight into aptamers and their utility in the form of aptasensors. It discusses how aptamer-based approaches have emerged as a novel strategy and its advantages over more resource-intensive and complex biochemical approaches.

Evaluation of a commercial latex agglutination test for detecting rotavirus A and human adenovirus in children's stool specimens

Objectives

Rotavirus A and human adenovirus are the two most common causes of infantile diarrhea; thus, it is of great importance to find out a rapid and accurate diagnostic method. This study aimed to evaluate the diagnostic significance of latex agglutination test for detection of rotavirus A and human adenovirus.

Methods

A prospective study was conducted on 214 diarrhea children from September 2018 to March 2019 in our hospital. Fresh stool samples were collected for detection of rotavirus A and human adenovirus by latex agglutination test and quantitative reverse transcription polymerase chain reaction (RT‐qPCR). Then, the consistency of results detected by these two methods was analyzed．

Results

With performing the latex agglutination test, it was revealed that positive rates for detecting rotavirus A virus and human adenovirus were 23.83% (51/214) and 25.24% (54/214), respectively. Meanwhile, results of RT‐qPCR showed that positive rates for detecting rotavirus A virus and human adenovirus were 58 (27.10%) and 59 (27.57%), respectively. Using RT‐qPCR as the gold standard, the sensitivity and specificity of the latex agglutination test for detecting rotavirus A were 81.03% and 97.44%, and the corresponding values for detecting human adenovirus were 76.27% and 94.19%, respectively.

Conclusion

This latex agglutination test showed a satisfactory consistency with RT‐qPCR for detecting rotavirus A and human adenovirus. The mentioned commercial assay may be highly appropriate for rapid screening of rotavirus A and human adenovirus.