Antibacterial activities of six acid-soluble [two degrees of deacetylation (DD) · three viscosities] and two water-soluble chitosans (two DD with similar viscosities) were examined against eight gram-negative (Pseudomonas fluorescens, Proteus vulgaris, Erwinia carotovora, Serratia marcescens, Escherichia coli, Vibrio parahaemolyticus, V. vulnificus, and Salmonella Typhimurium) and six gram-positive bacteria (Listeria monocytogenes, Staphylococcus aureus, Bacillus subtilis, B. cereus, Lactobacillus curvatus, and L. plantarum). Antibacterial activities of chitosans differed depending on the chitosan types and bacteria tested. Watersoluble chitosans inhibited bacterial growth by one to eight log cycles at 0.1% concentration; however, the effects were much lesser than those observed with 0.05% acid-soluble chitosans. Minimum inhibitory concentration (MIC) values (0.03% to above 0.1%) of acid-soluble chitosans were much lower than those (0.05% to above 0.8%) of water-soluble chitosans. Based on MIC values, the acid-soluble chitosan with 99% DD and lower viscosity (17.9 mPa s) was most effective in inhibiting bacteria growth among eight chitosans tested.

Reliable results of serologic positivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody before and after AstraZeneca (AZ) vaccination are essential to estimate the efficacy of vaccination. We assessed the positivity rates and associated factors using five SARS-CoV-2 antibody assays. A total of 228 paired serum samples (456 samples) were obtained from 228 participants. After baseline sampling, the second sampling was conducted between 11-28 days after the first dose of AZ. Sera were tested using five SARS-CoV-2 antibody assays, including two surrogate virus neutralization tests. A questionnaire on symptom, severity, and duration of adverse reactions was completed by all participants. The overall positive rates for SARS-CoV-2 antibody were 84.6% for Roche, 92.5% for Abbott, 75.4% for Siemens, 90.7% for SD Biosensor, and 66.2% for GenScript assays after the first dose of AZ vaccination. The positive rates and antibody titer of sera obtained between 21-28 days were significantly higher than those obtained between 11-20 days in all five assays. More severe and longer duration of adverse reactions were related to higher SARS-CoV-2 antibody levels. The agreements and correlations among the applied assays were substantial (к=0.73-0.95) and strong (ρ=0.83-0.91). A single dose of AZ vaccination led to high positivity rates based on the five assays. Days after vaccination and adverse reactions could help estimate serologic conversions. The results should be interpreted cautiously considering the applied assays and cutoffs. Our findings could inform decisions regarding vaccination and laboratory settings and, thus, contribute to the control of the spread of SARS-CoV-2 infection.

Early diagnosis of pneumococcal pneumonia facilitates appropriate antibiotic therapy. The urinary antigen test (UAT) is known to be useful for the diagnosis of pneumococcal pneumonia. This study aimed to evaluate the usefulness of UAT in the 13-valent pneumococcal conjugated vaccine (PCV13) era. Community-acquired pneumonia (CAP) cases aged ≥19 years were reviewed retrospectively. This study evaluated the utility of Streptococcus pneumoniae UAT (BinaxNOW(®) assay) for diagnosis of pneumococcal CAP, and the relation of the UAT positive rate to age, comorbidities, pneumonia severity, and pneumococcal serotypes. Among 752 microbiologically identified CAP cases, S. pneumoniae (36.7%) was the most common isolate, and of those cases, 56.4% were positive for UAT. UAT positivity varied by pneumococcal serotype (serotype 3, 50%; 9V/9A, 85%; 11A/11E, 54%; 14, 36.4%; 19A, 50%; and 23F, 37.5%), and was significantly increased since 2012, two years after introduction of PCV13. The positive rate of UAT was significantly related to CRP level (P = 0.007) and lobar pneumonia (P = 0.006), but not to age, co-morbidities or prior antibiotic therapy. In conclusion, urinary antigen detection varied depending on the S. pneumoniae serotype. In the PCV13 era, the serotype distribution of pneumococcal pneumonia may be changing, and the clinical usefulness of UAT needs to be monitored. The positive rate of UAT may be influenced by a localized bacterial burden and host reactions.

BackgroundLittle is known about the epidemiology on human papillomavirus (HPV) infection among HIV-infected men in Korea. The objective of this study was to determine the prevalence, genotype distribution and risk factors associated with anal HPV infection among HIV-infected men in Korea.MethodsA single-center cross-sectional study was conducted with HIV-infected men in Korea. Participants completed a detailed sexual behavior risk factor questionnaire. Anal samples were collected for cytology and HPV genotyping. Factors associated with anal HPV infection were assessed using multivariable logistic regression, stratifying by sexual behaviour.ResultsA total of 201 HIV-infected men were included in the study: 133 were from men who have sex with men (MSM) and 68 from men who have sex with women (MSW). Any anal HPV infection was detected in 82.7% of HIV-infected MSM and in 51.5% of HIV- infected MSW (P < 0.001). High-risk HPV (HR-HPV) prevalence was higher among MSM (47.4%) than MSW (25.0%; P = 0.002). The HR-HPV types identified most frequently were HPV 16 (11%), HPV 18 (9.9%), and HPV 58 (5%) in MSM, and HPV 58(11%) and HPV 16 (8.9%) in MSW. Prevalence of any HPV types in 9-valent vaccine types was higher among MSM than MSW (47.4% vs 22.1%. P = 0.001). Abnormal anal cytology was more commonly detected in MSM than MSW (42.9% vs.19.1%, P < 0.001). In HIV-infected MSM, higher number of lifetime male sex partners was significantly associated with any anal HPV infection, but age was a significant risk factor associated with anal HR-HPV infection.ConclusionAnal HPV infection was highly prevalent in HIV-infected MSM in Korea, and also commonly found in HIV-infected MSW. In HIV-infected MSM, the significant risk factor for being infected with any HPV infection was lifetime number of male sexual partners, and with anal oncogenic HPV infection was age.

Reliable results for serologic positivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody after the second dose of AstraZeneca (AZ) vaccination are important to estimate the real efficacy of vaccination. We evaluated the positivity rates and the changes of semi-quantitative antibody titers before and after the first and second ChAdOx1 nCoV-19 Vaccinations using five SARS-CoV-2 antibody assays, including two surrogate virus neutralization tests. A total of 674 serum samples were obtained from 228 participants during three blood sampling periods. A questionnaire on symptoms, severity and adverse reactions duration was completed after the second vaccination. The overall positive rates for all assays were 0.0-0.9% before vaccination, 66.2-92.5% after the first vaccination, and 98.2-100.0% after the second vaccination. Median antibody titers in five assays after the second dose of vaccination were increased compared to those after the first dose (106.4-fold increase for Roche total antibody, 3.6-fold for Abbott IgG, 3.6-fold for Siemens, 1.2-fold for SD Biosensor V1 neutralizing antibody, and 2.2-fold for GenScript neutralizing antibody). Adverse reactions reduced after the second dose in 89.9% of participants compared to after the first dose. Overall, the second vaccination led to almost 100% positivity rates based on these SARS-CoV-2 antibody assays. The results should be interpreted with caution, considering the characteristics of applied assays. Our findings could inform decisions regarding vaccination and the use of immunoassays, thus, contributing to the SARS-CoV-2 pandemic control.