Evaluation of different platforms for the detection of anti-SARS coronavirus-2 antibodies, Thailand.

BACKGROUND: Antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) help determine previous infection in individuals, regardless of whether they are asymptomatic or symptomatic. The detection of antibodies serves several purposes, including supporting other assays for disease diagnosis, conducting seroepidemiological studies, and evaluating vaccines. Many platforms of immunological methods for anti-SARS-CoV-2 antibody detection and their performance require validation. METHODS: This study evaluated the test performance of three autoanalyzer-based assays (Architect IgG, Vitros IgG, and Vitros total Ig) and one manual ELISA (Wantai total Ig) against a microneutralization (microNT) assay on the detection of SARS-CoV-2 antibodies. Furthermore, an indirect immunofluorescence assay verified the discordant results between the microNT and commercial assays. The test sensitivity, specificity, positive predictive value, and negative predictive value were determined based on four groups of 1005 serum samples: 102 COVID-19 prepandemic sera, 45 anti-SARS-CoV-2 positive sera, 366 sera of people at risk, and 492 sera of citizens returning from countries with a high prevalence of infection. RESULTS: The analyses as a whole showed that the performance of these commercial assays was comparable. Each group was also analysed separately to gain further insight into test performance. The Architect did not detect two positive sera of people at risk (prevalence of infection 0.55%). The other methods correctly identified these two positive sera but yielded varying false-positive results. The group of returning travellers with an infection rate of 28.3% (139 of 492) better differentiated the test performance of individual assays. CONCLUSIONS: High-throughput Architect and Vitros autoanalyzers appear appropriate for working on large sample sizes in countries that can afford the cost. The Wantai ELISA, while requiring more individual time and technical skill, may provide reliable results at a lower cost. The selection of assays will depend on the laboratory facilities and feasibility.

Thrombosis and Bleeding Risk Scores Are Strongly Associated with Mortality in Hospitalized Patients with COVID-19: A Multicenter Cohort Study.

Background: Internationally established guidelines mention pharmacological prophylaxis for all hospitalized COVID-19 patients. However, there are concerns regarding the efficacy and safety of anticoagulants. This study investigated the associations between thrombosis/bleeding risk scores and clinical outcomes. Methods: We conducted a retrospective review of adult patients admitted to two hospitals between 2021 and 2022. We analyzed clinical data, laboratory results, low molecular weight heparin (LMWH) use, thrombosis, bleeding, and 30-day survival. Results: Of the 160 patients, 69.4% were female, and the median age was 59 years. The rates of thrombotic complications and mortality were 12.5% and 36.3%, respectively. LMWH prophylaxis was administered to 73 of the patients (45.6%). The patients with high Padua prediction scores (PPS) and high IMPROVEVTE scores had a significantly higher risk of venous thromboembolism (VTE) compared to those with low scores (30.8% vs. 9.0%, p = 0.006 and 25.6% vs. 7.7%, p = 0.006). Similarly, elevated IMPROVEVTE and IMPROVEBRS scores were associated with increased mortality (hazard ratios of 7.49 and 6.27, respectively; p < 0.001). Interestingly, LMWH use was not associated with a decreased incidence of VTE when stratified by risk groups. Conclusions: this study suggests that COVID-19 patients with high thrombosis and bleeding risk scores have a higher mortality rate.

Higher correlation between neutralizing antibodies and surrogate neutralizing or binding antibodies in COVID-19 patients than vaccine recipients.

This study determined the seropositive rates and levels of antibodies to severe acute respiratory syndrome coronavirus-2 in 50 patients and 108 vaccinees using microneutralization test (MNT), surrogate virus neutralization test (sVNT), chemiluminescent microparticle immunoassay (CMIA), and electrochemiluminescence immunoassay (ECLIA). MNT, as the reference method, employed living clade S and Delta viruses to measure neutralizing (NT) antibodies, while sVNT employed wild type strain and Delta receptor-binding domains (RBD) as the test antigens to measure sVNT antibodies. CMIA and ECLIA employed only one version of RBD to measure the binding antibodies. Our study performed S gene sequencing of the test virus to exclude undesired mutants that might lead to changes in antibody levels in MNT assay. We showed that spike protein amino acid sequences of our Delta virus contained 13 amino acid changes, with 3 related to the reduced neutralization. The MNT assay showed a significant reduction in seropositive rates and antibody levels in the patients' sera when the Delta variant replaced clade S as the test virus. In contrast, the seropositive rates determined by sVNT assay using wild type strain RBD and Delta RBD were non-significantly different, suggesting that sVNT assay could not identify the difference between the antigenicity of wild type RBD and Delta RBD. Furthermore, the correlation between the levels of NT and sVNT antibodies was moderate with the patients' sera but modest with the post-vaccination sera. The seropositive rates in the patients, as determined by CMIA or ECLIA, were not different from the MNT assay using clade S, but not Delta, as the test virus. In all analyses, the correlations between the antibody levels measured by MNT and the other 3 assays were modest to moderate, with the r-values of 0.3500-0.7882.

Disseminated viridians streptococcus (Streptococcus mitis) infection presenting with toxic shock-like syndrome.

The authors report a case of a 35-year-old man with no known underlying disease who presented with fever, cellulitis with hemorrhagic blebs on the left leg, monoarthricular left knee arthritis, multiple organ failure and septic shock. His clinical syndrome was compatible with toxic shock syndrome and his blood grew alpha hemolytic (viridians) Streptococcus mitis. To our knowledge, there are few reported cases of toxic shock syndrome cause by Streptococcus mitis in immune-competent adults.

Seroprevalence of anti-SARS-CoV-2 antibodies in Thai adults during the first three epidemic waves.

This study determined the presence of anti-SARS-CoV-2 antibodies in 4964 individuals, comprising 300 coronavirus disease-19 (COVID-19) prepandemic serum samples, 142 COVID-19 patients, 2113 individuals at risk due to their occupations, 1856 individuals at risk due to sharing workplaces or communities with COVID-19 patients, and 553 Thai citizens returning after spending extended periods of time in countries with a high disease prevalence. We recruited participants between May 2020 and May 2021, which spanned the first two epidemic waves and part of the third wave of the COVID-19 outbreaks in Thailand. Their sera were tested in a microneutralization and a chemiluminescence immunoassay for IgG against the N protein. Furthermore, we performed an immunofluorescence assay to resolve discordant results between the two assays. None of the prepandemic sera contained anti-SARS-CoV-2 antibodies, while antibodies developed in 88% (15 of 17) of the COVID-19 patients at 8-14 days and in 94-100% of the patients between 15 and 60 days after disease onset. Neutralizing antibodies persisted for at least 8 months, longer than IgG antibodies. Of the 2113 individuals at risk due to their occupation, none of the health providers, airport officers, or public transport drivers were seropositive, while antibodies were present in 0.44% of entertainment workers. Among the 1856 individuals at risk due to sharing workplaces or communities with COVID-19 patients, seropositivity was present in 1.9, 1.5, and 7.5% of the Bangkok residents during the three epidemic waves, respectively, and in 1.3% of the Chiang Mai people during the first epidemic wave. The antibody prevalence varied between 6.5 and 47.0% in 553 Thai people returning from high-risk countries. This serosurveillance study found a low infection rate of SARS-CoV-2 in Thailand before the emergence of the Delta variant in late May 2021. The findings support the Ministry of Public Health's data, which are based on numbers of patients and contact tracing.

An outbreak of botulism in Thailand: clinical manifestations and management of severe respiratory failure.

BACKGROUND: Northern Thailand's biggest botulism outbreak to date occurred on 14 March 2006 and affected 209 people. Of these, 42 developed respiratory failure, and 25 of those who developed respiratory failure were referred to 9 high facility hospitals for treatment of severe respiratory failure and autonomic nervous system involvement. Among these patients, we aimed to assess the relationship between the rate of ventilator dependence and the occurrence of treatment by day 4 versus day 6 after exposure to bamboo shoots (the source of the botulism outbreak), as well as the relationship between ventilator dependence and negative inspiratory pressure. METHODS: We reviewed the circumstances and timing of symptoms following exposure. Mobile teams treated patients with botulinum antitoxin on day 4 or day 6 after exposure in Nan Hospital (Nan, Thailand). Eighteen patients (in 7 high facility hospitals) with severe respiratory failure received a low- and high-rate repetitive nerve stimulation test, and negative inspiratory pressure was measured. RESULTS: Within 1-65 h after exposure, 18 of the patients with severe respiratory failure had become ill. The typical clinical sequence was abdominal pain, nausea and/or vomiting, diarrhea, dysphagia and/or dysarthria, ptosis, diplopia, generalized weakness, urinary retention, and respiratory failure. Most patients exhibited fluctuating pulse and blood pressure. Repetitive nerve stimulation test showed no response in the most severe stage. In the moderately severe stage, there was a low-amplitude compound muscle action potential with a low-rate incremented/high-rate decremented response. In the early recovery phase, there was a low-amplitude compound muscle action potential with low- and high-rate incremented response. In the ventilator-weaning stage, there was a normal-amplitude compound muscle action potential. Negative inspiratory pressure variation among 14 patients undergoing weaning from mechanical ventilation was observed. Kaplan-Meier survival analysis identified a shorter period of ventilator dependency among patients receiving botulinum antitoxin on day 4 (P=.02). CONCLUSIONS: Patients receiving botulinum antitoxin on day 4 had decreased ventilator dependency. In addition, for patients with foodborne botulism, an effective referral system and team of specialists are needed.

Balamuthia mandrillaris meningoencephalitis: the first case in southeast Asia.

We present a case of 23-year-old man with acute meningoencephalitis, accompanied by inflammation of a nasal ulcer. He had been healthy until six months prior to admission to the hospital when he had a motorcycle accident. A star-shaped wound at his nose was incurred after falling into a swamp. A computed tomogram of the brain showed two nonenhancing hypodense lesions at the left caudate nucleus and the right parietal lobe, ependymitis and leptomeningeal enhancement. A skin biopsy showed chronic noncaseous granulomatous inflammation without demonstrated microorganisms. The patient did not respond to the empirical treatment with cloxacillin, ceftriaxone, and amphotericin B, and eventually died on the thirteenth day of hospitalization. At autopsy, hematoxylin and eosin-stained brain sections showed a chronic necrotizing inflammation with numerous amebic trophozoites and rare cysts. Definitive identification of Balamuthia mandrillaris was made by fluorescent immunohistochemical analysis. There were 10 Naegleria fowleri primary amebic meningoencephalitis, eight Acanthamoeba granulomatous amebic encephalitis, and three Acanthamoeba meningitis in Thailand. To our knowledge, this case is the first reported case of B. mandrillaris in Southeast Asia.

Streptococcus suis meningitis in Thailand.

Streptococcus suis may be the second most common cause of adult streptococcal meningitis. The clinical and epidemiological data of S. suis meningitis are occasionally reviewed. To date, there have been only two large case series from Hong Kong and the Netherlands. We describe twelve cases of S. suis meningitis who were admitted to Chulalongkorn University Hospital, Bangkok, during a 6-year period between 1997 and 2002. A comparative review of case reports of S. suis meningitis in Thailand, Hong Kong, and the Netherlands is presented and revealed no significant differences between the three series. However, the cases from Thailand and Hong Kong had a significantly greater number of associated skin and soft tissue infections. Clinically, S. suis meningitis may appear acute or with a more chronic course.

Utility of Cryptococcal Antigen Screening and Evolution of Asymptomatic Cryptococcal Antigenemia among HIV-Infected Women Starting Antiretroviral Therapy in Thailand.

Cryptococcal meningitis (CM) remains a significant HIV-associated opportunistic infection in Southeast Asia and Africa, with a high burden of disease and a high mortality rate despite the availability of antiretroviral therapy (ART). We retrospectively examined the utility of cryptococcal antigen screening to identify risk for CM among 211 Thai women initiating ART. Antigenemia prevalence was 11% (n = 9) among 84 women with a CD4 count <100 cells/mm(3). Screening identified all women who later developed CM. Cryptococcal antigen titers decreased over time with ART. Our study confirmed findings from previous studies in Thailand and South Africa and provided novel observational data regarding the course of cryptococcal antigenemia in patients initiating ART and the poor efficacy of low-dose fluconazole prophylaxis in preventing CM among patients with antigenemia.

An evaluation of hepatitis B virus diagnostic methods and responses to antiretroviral therapy among HIV-infected women in Thailand.

Coinfection with HIV and hepatitis B virus (HBV) is common in resource-limited settings but is frequently not diagnosed. The authors retrospectively tested specimens for HBV in HIV-infected Thai women who had participated in an antiretroviral therapy (ART) clinical study. A substantial proportion (27 of 211; 13%) of HIV-infected women were HBV coinfected. Among HIV/HBV-coinfected women, the authors observed similar rates of antiretroviral-associated liver toxicity (despite nevirapine [NVP] use) and CD4 count reconstitution as observed in HIV-monoinfected women. Hepatitis B surface antigen (HBsAg) screening detected the majority (81%) of HBV coinfections, including all 5 HBV-coinfected women who did not suppress HBV despite 48 weeks of lamivudine (3TC)-containing ART and could be used to tailor ART for patients diagnosed with HBV coinfection in accordance with World Health Organization guidelines. Although HBsAg screening did not diagnose 5 occult HBV coinfections, these women achieved HBV suppression on 3TC-containing ART, suggesting that not detecting occult HBV coinfection would have limited clinical impact.

Association of Nevirapine Levels with Rash or Hepatotoxicity Among HIV-Infected Thai Women.

BACKGROUND: We performed a nested case-control study of Thai women prescribed nevirapine-based antiretroviral therapy (ART) to determine if development of rash or hepatotoxicity during the first 24 weeks of treatment is associated with plasma nevirapine concentrations. METHOD: From May 2005-January 2007, we enrolled 217 women initiating nevirapine-based ART in Thailand. Cases (n = 54) were women who during the first 24 weeks of treatment with nevirapine developed rash (any grade, n = 42) or hepatotoxicity (≥grade 2, n = 22, [10 had both]). Controls were the next enrolled woman who was confirmed not to meet the case definition during the first 24 weeks. Nevirapine concentrations after the two week lead-in dose of 200 mg once daily were compared between cases and controls by Wilcoxon rank-sum tests. RESULTS: We found no difference in Week 2 pre-dose nevirapine concentrations: cases median = 3,528 ng/mL (n = 24), controls median = 3,150ng/mL (n = 30), p = 0.5. Cases had higher post-dose nevirapine concentrations (median = 6,150 ng/mL, n = 21) than controls (median = 4,746 ng/mL, n = 20, p = 0.02). When limited to cases who developed a rash at Week 2, we found no differences in the pre-dose (median = 3,270 ng/mL, n = 12, p = 0.9) or post-dose nevirapine concentration (median = 5,443 ng/mL, n = 9, p = 0.4) compared with controls. CONCLUSIONS: We cannot conclude definitively that nevirapine concentrations at two weeks of therapy are associated with rash or hepatotoxicity. It is unlikely that therapeutic drug monitoring at that time will improve identification of patients at risk for rash or hepatotoxicity.

Immune reconstitution syndrome associated with parvovirus B19-induced pure red cell aplasia during highly active antiretroviral therapy.

Persistent parvovirus B19 (B19) manifested as chronic pure red cell aplasia (PRCA) has been described in HIV patients. Immune reconstitution syndrome (IRS) is an immune response to an occult opportunistic pathogen or tumor antigen, usually occurs after antiretroviral treatment. We describe the first case of IRS associated with B19-induced PRCA during highly active antiretroviral therapy.