To study heterogeneity in SARS-CoV-2 IgG response titre in patients recovered from COVID-19.

The COVID-19 pandemic caused a serious health challenge to the entire mankind. The association between clinical characteristics of disease and formation of neutralizing antibodies have not well studied. A prospective study was conducted for patients recovered from confirmed SARS-CoV-2 infections from 1st August 2020 to 28th February 2021, to study the association between SARS-CoV-2 IgG antibody response titres and clinical characteristics of the disease. A total 92 patients were included in the study. Median age was 52 years; majority were male and middle or old aged.  About 48% patients required hospitalization and 38.3% had moderate CT severity score. Positive SARS-CoV-2-IgG was detected in all patients except one. On comparing the antibody titres among various sub-groups of COVID-19 recovered patients, old age was the only factor associated with statistically significant higher antibody response (28 AU/ml for age<35 years, 53 AU/ml for age group 35-60, and 71 AU/ml for age group >60 years, p=0.01). Severity of infection, worse CT severity scores, need of hospitalization, oxygen or ventilatory support were associated with higher antibody titres but were not statistically significant. There was a strong correlation of antibody titres when analysed for age of study population (Spearman correlation=0.39, p<0.001); whereas a weak correlation (Spearman correlation=0.03, p=0.753) was seen when analysed for CT severity score. Elderly patients had higher antibody titre after recovery from Covid-19 infection. Severity of disease, need of hospitalisation or oxygen/mechanical ventilation did not influence the antibody titre.

Genetic relatedness of Candida albicans bloodstream infection clinical isolates in Malaysia

Aims: The aim of this study was to investigate the genetic relatedness of the most prevalent Candida bloodstream infection (BSI) species in in a Malaysian population via Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) fingerprinting. Methodology and results: The genomic DNA of 43 Candida BSI blood culture samples obtained from Universiti Malaya Medical Centre (UMMC) was isolated, after which species identification was carried out using PCR with ITS-1 and ITS-4 pan-fungal primers in conjunction with CHROMagar™ Candida. The predominant Candida species in the BSI samples is Candida albicans (14 out of 43 isolates). RAPD-PCR on these 14 C. albicans clinical isolates was performed using PST as the arbitrary primer. Data analysis using MEGA found an overall non-relatedness of these 14 clinical isolates [average similarity coefficient (SAB) value 0.733±0.172]. Following in-depth analysis, five of the 14 isolates were observed to be identical (SAB values of 1.00 each), four isolates had SAB values of 0.80-0.99, indicating that they are highly similar, but are non-identical, while five isolates are unrelated (SAB lower than 0.80). This suggests that microevolution might have occurred and that these clinical isolates may possibly belong to different strains. Conclusion, significance and impact of study: A fair degree of genetic heterogeneity was found among the 14 C. albicans isolates from UMMC. To our knowledge, this is the first report on the genetic profiles of C. albicans bloodstream infection isolates from Malaysia, warranting further studies in the possible evolutionary trends within this Candida species in Malaysia. Keywords: Randomly Amplified Polymorphic DNA PCR (RAPD-PCR), Candida albicans, Candida bloodstream infections, Genetic relatedness, DNA fingerprinting