Background and Aim: Clostridium toxins are widely used as medicinal agents. Many active metabolic enzymes, including sialidase (neuraminidase), hyaluronidase, and collagenase, contribute to the mechanism of action of these toxins. Sialidase from Clostridium perfringens recognizes and degrades sialic acid receptors in the host cell glycoprotein, glycolipid, and polysaccharide complexes. Sialic acid promotes the adhesion of various pathogens, including viruses, under pathological conditions. This study aimed to investigate the potential of C. perfringens sialidase protein to inhibit Newcastle disease virus (NDV) infection in ovo model. Materials and Methods: C. perfringens was characterized by molecular identification through polymerase chain reaction (PCR) and is cultured in a broth medium to produce sialidase. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis was conducted to characterize the sialidase protein. In contrast, enzymatic activity and protein concentration were carried out using a neuraminidase assay kit and Bradford to obtain suitable active substances. Furthermore, embryonated chicken egg models were used to observe the toxicity of several sialidase doses. Then, the hemagglutination (HA) titer was obtained, and absolute quantitative reverse transcription–PCR assay was performed to measure the viral replication inhibitory activity of sialidase against NDV. Results: Each isolate had a specific sialidase gene and its product. The sialidase derived from C. perfringens could hydrolyze the sialic acid receptor Neu5Ac (2,6)-Gal higher than Neu5Ac (2,3)Gal in chicken erythrocytes, as observed by enzyme-linked lectin assay. A significant difference (p = 0.05) in the HA titer in the pre-challenge administration group at dosages of 375 mU, 187.5 mU, and 93.75 mU in the competitive inhibition experiment suggests that sialidase inhibits NDV reproduction. Quantification of infective viral copy confirmed the interference of viral replication in the pre-challenge administration group, with a significant difference (p = 0.05) at the treatment doses of 750 mU, 375 mU, and 46.87 mU. Conclusion: The potency of sialidase obtained from C. perfringens was shown in this study, given its ability to reduce the viral titer and copy number in allantoic fluids without adversely impacting the toxicity of the chicken embryo at different concentrations.

Introduction. The COVID-19 pandemic has entered a new phase with the roll-out of several vaccines worldwide at an accelerated phase. The occurrence of a more severe presentation of COVID-19 after vaccination may affect policymakers decision-making and vaccine uptake by the public. Vaccine-associated disease enhancement (VADE) is the modified presentation of infections in individuals after having received a prior vaccination. Currently, little is known about the potential of vaccine-associated disease enhancement (VADE) following COVID-19 immunization. Case Illustration. We herewith report two patients admitted with confirmed COVID-19 pneumonia with a history of CoronaVac vaccination. The first patient with a relatively milder course of the disease had received two doses of CoronaVac, whereas the second patient with a more progressive course of the disease received only one dose before developing symptoms and being admitted to the hospital. Our observations suggest that vaccination could act in boosting the inflammatory process and reveal the previously asymptomatic COVID-19 illness. Theoretically, vaccines could induce VADE, where only suboptimal, nonprotective titers of neutralizing antibodies were produced or proinflammatory T-helper type 2 response was induced. Secondly, enhanced respiratory disease (ERD) could manifest, where pulmonary symptoms are more severe due to peribronchial monocytic and eosinophilic infiltration. Understanding VADE is important for the decision-making by the public, clinicians, and policymakers and is warranted for successful vaccination uptake. Conclusion. We report two cases of patients developing COVID-19 shortly after CoronaVac vaccination in which VADE is likely. We recommend that current vaccination strategies consider the measurement of neutralizing antibody titer as a guide in ensuring the safest strategy for mass immunization. Studies are needed to investigate the true incidence of VADE on vaccinated individuals as well as on how to differentiate between VADE and severe manifestations of COVID-19 that are unrelated to vaccination.

Indonesia first reported SARS-CoV-2 in March 2020. From March to April, clinical microbiology laboratory Universitas Indonesia in Jakarta received 4617 specimens with 12.6% positivity rate and 22% asymptomatic case. The result of this study could give an early picture of Indonesia’s COVID 19 outbreak situation.

BACKGROUND Leprosy is an infectious disease that is still a health problem worldwide, including in Indonesia. The clinical symptoms are similar to other skin diseases and it is difficult to establish a diagnosis for paucibacillary (PB) leprosy. Current serological and histopathological tests have limitations, especially in patients with negative acid-fast bacilli (AFB). Serological tests often give false-negative results, while histopathological results often consist of non-specific inflammation. Probe-based real-time polymerase chain reaction (RT-PCR) assays is an alternative test that may be more sensitive and more specific to detect Mycobacterium leprae. METHODS This study was done in June 2015 until March 2016; detected M. leprae in PB patients with negative AFB smears using TaqMan® probe-based RT-PCR assay on slit skin scrapings and skin biopsy specimens from 24 patients. The skin scrapings were obtained from skin tissue on ear lobes, skin lesions, as well as those from biopsy. Samples were tested with RT-PCR while histopathological examinations were only performed on skin from biopsy. RESULTS The RT-PCR assay showed positive results of 21%, 25%, and 96% for specimens obtained from skin scrapings of the ear lobe, skin lesions, and skin biopsy, respectively. On the other hand, the positive rate for the histopathological test from skin biopsy was 79%. It indicated that the TaqMan® RT-PCR assay could increase the diagnostic capacity of histopathological examination by as much as 17%. CONCLUSIONS TaqMan® PCR assay can improve the diagnostic capacity of histopathological examinations, which could be used as the new gold standard for the diagnosis of leprosy.

The current naso-oropharyngeal swab for SARS-CoV-2 detection faces several problems, such as waste issues and its use for quantitative studies. This study aimed to evaluate the total RNA and viral loads from different upper respiratory tract swabs types and whether SARS-CoV-2 quantification can use the current internal control for normalization. This cross-sectional study collected positive specimens with single oropharyngeal or nasopharyngeal swabs and naso-oropharyngeal swabs. The samples were extracted, tested with qualitative RT‒PCR, and then tested with quantitative RT‒PCR. The RNA eluate was measured for the total RNA concentration. The total RNA concentration, viral load, and RNaseP Ct values were collected and analysed statistically. The positive results came from 41 oropharyngeal swabs, 34 nasopharyngeal swabs, and 36 naso-oropharyngeal swabs. The total RNA increased significantly from oropharyngeal swabs to nasopharyngeal swabs to naso-oropharyngeal swabs. Significant differences in RNaseP Ct values between groups and their correlations with total RNA were found. In addition, the increase in the total RNA and the RNaseP Ct values were unrelated to the viral load. The physical features in the naso-oropharyngeal area and the swabbing procedures could affect the total RNA but not the viral load. However, since the virus particles could present inside and outside human cells, the increase in collected human cells may not always be followed by the viral load increase. Normalization using the RNaseP Ct value became unnecessary due to the factors mentioned above. Therefore, a careful approach is needed in viral load studies of swab specimens.