Antimicrobial susceptibilities and molecular characterization of toxin-positive clostridium difficile isolates: The first report on the presence of hypervirulent strains from Turkey [Toksin Pozitif Clostridium difficile Izolatlarinin Antimikrobiyal Duyarliliklari ve Moleküler Karakterizasyonu: Türkiye'den Hipervirülan Suşlarin Varligi ile Ilişkili Ilk Bildirim]

PubMedID: 28929960Clostridium difficile infection is one of the most important hospital-acquired infections. Infections caused by hypervirulent C.difficile strains which produce toxins at high levels, have higher morbidity and mortality rates, more complications and relapses. They are characterized by higher sporulation ratios and resistance rates for fluoroquinolones. In order to prevent serious morbidities, mortalities and remarkable increase in health costs, highly pathogenic C.difficile strains must be identified before causing severe outbreaks. The aim of this study was to determine the antimicrobial susceptibilities and molecular characteristics of 61 C.difficile strains isolated by culture from toxin-positive fecal samples of patients who were admitted to three different laboratories in Ankara, between September 2012 and November 2014. Antimicrobial susceptibilities were determined by using gradient test strips and results were interpreted according to the current CLSI and EUCAST criteria. The presence of toxin genes was investigated by polymerase chain reaction (PCR), and mutations in the tcdC gene were determined by sequence analysis following PCR amplification. Genetic characterization of one hypervirulent strain was performed by Public Health Institution of Turkey using the CenoType CDiff (Hain Lifescience, Germany) test. All strains were susceptible to vancomycin and metronidazole. Three (4.9%) isolates were resistant to moxifloxacin with a minimum inhibitory concentration (MIC) of > 8 µg/ml. The MIC 50 and MIC 90 values for erythromycin and clindamycin were 1.5-3 µg/ml, and 2-4 µg/ml, respectively. All strains carried the tcdA and tcdB genes, and 1 (1.6%) was positive for the binary-toxin (cdtA and cdtB) genes. The binary-toxin positive strain carried a 54 bp deletion as well as a single nucleotide change in the tcdC gene. Various single nucleotide changes were found in the tcdC gene of 12 strains (19.6%). Our results have shown that, hypervirulent strains exist in our country, but we have no evidence for the presence of ribotype 027 yet. On the other hand, when the increasing incidence of these strains through out the world is taken into consideration, it would be of great importance to perform surveillance studies and characterize the isolated strains

Clinical evaluation of DIAGNOVIR SARS-CoV-2 ultra-rapid antigen test performance compared to PCR-based testing

Coronavirus Disease-19 (COVID-19) is a highly contagious infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The development of rapid antigen tests has contributed to easing the burden on healthcare and lifting restrictions by detecting infected individuals to help prevent further transmission of the virus. We developed a state-of-art rapid antigen testing system, named DIAGNOVIR, based on immune-fluorescence analysis, which can process and give the results in a minute. In our study, we assessed the performance of the DIAGNOVIR and compared the results with those of the qRT-PCR test. Our results demonstrated that the sensitivity and specificity of the DIAGNOVIR were 94% and 99.2%, respectively, with a 100% sensitivity and 96.97% specificity, among asymptomatic patients. In addition, DIAGNOVIR can detect SARS‑CoV‑2 with 100% sensitivity up to 5 days after symptom onset. We observed that the DIAGNOVIR Rapid Antigen Test’s limit of detection (LoD) was not significantly affected by the SARS‑CoV‑2 variants including Wuhan, alpha (B1.1.7), beta (B.1.351), delta (B.1.617.2) and omicron (B.1.1.529) variants, and LoD was calculated as 8 × 102, 6.81 × 101.5, 3.2 × 101.5, 1 × 103, and 1 × 103.5 TCID50/mL, respectively. Our results indicated that DIAGNOVIR can detect all SARS-CoV-2 variants in just seconds with higher sensitivity and specificity lower testing costs and decreased turnover time. © 2023, The Author(s).Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]