[Investigation of Biofilm Formation, Anti-Quorum Sensing Activity and Antimicrobial Resistance in Corynebacterium Species Isolated from Clinical Samples]. / Klinik Örneklerden Izole Edilen Corynebacterium Türlerinde Biyofilm Olusumunun, Anti-Quorum Sensing Aktivitesinin ve Antimikrobiyal Direnç Durumunun Arastirilmasi.

An increasing number of different clinical infections caused by Corynebacteria have been reported in the last decade. The aim of this study was to evaluate the antibiotic resistance rates, biofilm formation capacities and to investigate the ''anti-quorum-sensing (anti-QS)'' activities of corynebacteria, which were divided into three groups according to the type of growth in culture (pure, with another pathogenic bacterium and polymicrobial growth). In total 240 Corynebacterium spp. isolates from different clinical specimens sent to the medical microbiology laboratories of Düzce University Faculty of Medicine Hospital and Basaksehir Çam and Sakura City Hospital between June 2021 and June 2022 were classified into three groups: pure, isolated with another pathogen and polymicrobial, according to their growth patterns in culture. Bacteria were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) Biotyper (Bruker, Germany) at an external centre. Antibiotic susceptibilities were determined by disc diffusion method and for vancomycin broth microdilution method was used. Results were interpreted according to EUCAST recommendations. The biofilm-forming properties of the isolates were determined quantitatively. Bioactive components of 17 isolates with strong biofilm formation were extracted and anti-QS activity was determined by agar diffusion method using Chromobacterium violaceum ATCC 12472 strain and then violacein pigment production was measured quantitatively. Of the 240 Corynebacterium spp. isolates, 138 (58%) were pure, 52 (22%) were isolated with another pathogen and 50 (20%) were part of a polymicrobial infection. Of the isolates, 140 were identified as C.striatum, 34 as C.amycolatum and 24 as Corynebacterium afermentans. When the antibiotic resistance rates of the Corynebacterium isolates were analysed according to the groups, the resistance rates to rifampicin and tetracycline antibiotics were found to be statistically significantly lower in the polymicrobial group than in the other groups. The resistance rates to penicillin, clindamycin, ciprofloxacin, moxifloxacin, rifampicin, tetracycline and linezolid were 96.7%, 88.3%, 86.3%, 73.8%, 62.5%, 59.2% and 0.8%, respectively. While all isolates were susceptible to vancomycin, linezolid resistance was detected in two C.afermentans isolates. When the biofilm formation ability was analysed, it was observed that 87 (36.3%) isolates formed biofilm. The biofilm formation rate of the isolates in the polymicrobial growth group was lower than the other two groups. The anti-QS activity of 17 isolates with strong biofilm formation was investigated and none of the Corynebacterium extracts tested were found to have anti-QS activity (inhibition of violacein pigment production without inhibiting bacterial growth) in the QS study with C.violaceum, whereas five isolate extracts had antibacterial activity (inhibition of bacterial growth). Four of the bacterial extracts with antimicrobial activity belonged to C.amycolatum and one to C.afermentans. In conclusion, when both antibiotic resistance rates and biofilm formation rates were analysed, the corynebacteria growing in culture with another pathogen showed similar characteristics to the corynebacteria growing as a pure culture. Therefore, it was thought that corynebacteria growing with another pathogen should not be ignored. In addition, the antimicrobial effects of some corynebacterial extracts suggested that more QS studies should be carried out with microbiota bacteria.

Monitoring of antibody levels in healthcare workers after inactivated coronavirus disease 19 vaccination.

OBJECTIVE: Because of the coronavirus disease 19 pandemic, studies on vaccination are being conducted in our country as well as across the world. In this study, the antibody levels in healthcare workers vaccinated with two doses of inactivated vaccine and the factors affecting these levels were investigated. METHODS: Randomly selected volunteers from healthcare workers, who had been vaccinated with two doses of inactivated vaccine in January to February 2021, were included in the study. Blood samples were drawn twice, 1 month and 6 months after the second dose vaccine (CoronaVac:Sinovac Life Science Co, Ltd, Beijing, China). The antibody levels were determined by the chemiluminescence microparticle immunoassay method using kits for quantitative detection of immunoglobulin class G antibodies to severe acute respiratory syndrome coronavirus 2. RESULTS: The mean antibody levels of 129 volunteers were 1232.5 (min: 103 to max: 7151) AU/mL in the first month and 403.5 (min: 23 to max: 4963) AU/mL in the sixth month. According to the survey results, 91 (71%) volunteers had not been diagnosed with coronavirus disease 19 before vaccination. The antibody levels 1 month and 6 months after the second dose of vaccination were significantly higher in those who had been diagnosed with coronavirus disease 19 before vaccination than in those who had not. It was found that age, gender, fast food, or healthy nutrition had no effect on antibody levels. CONCLUSION: Vaccines are very important both to protect against coronavirus disease 19 and to experience only a mild form of the disease. Immunoglobulin class G levels formed after vaccination may be affected by many factors and may decrease over time.

Monitoring of antibody levels in healthcare workers after inactivated coronavirus disease 19 vaccination

SUMMARY OBJECTIVE: Because of the coronavirus disease 19 pandemic, studies on vaccination are being conducted in our country as well as across the world. In this study, the antibody levels in healthcare workers vaccinated with two doses of inactivated vaccine and the factors affecting these levels were investigated. METHODS: Randomly selected volunteers from healthcare workers, who had been vaccinated with two doses of inactivated vaccine in January to February 2021, were included in the study. Blood samples were drawn twice, 1 month and 6 months after the second dose vaccine (CoronaVac:Sinovac Life Science Co, Ltd, Beijing, China). The antibody levels were determined by the chemiluminescence microparticle immunoassay method using kits for quantitative detection of immunoglobulin class G antibodies to severe acute respiratory syndrome coronavirus 2. RESULTS: The mean antibody levels of 129 volunteers were 1232.5 (min: 103 to max: 7151) AU/mL in the first month and 403.5 (min: 23 to max: 4963) AU/mL in the sixth month. According to the survey results, 91 (71%) volunteers had not been diagnosed with coronavirus disease 19 before vaccination. The antibody levels 1 month and 6 months after the second dose of vaccination were significantly higher in those who had been diagnosed with coronavirus disease 19 before vaccination than in those who had not. It was found that age, gender, fast food, or healthy nutrition had no effect on antibody levels. CONCLUSION: Vaccines are very important both to protect against coronavirus disease 19 and to experience only a mild form of the disease. Immunoglobulin class G levels formed after vaccination may be affected by many factors and may decrease over time.