Changes in antimicrobial resistance of Enterococcus spp. Over a few years.

In this study, we aimed to review the resistance rates of high-level aminoglycosides compared to the resistance rates of other antimicrobials and review the trends in minimum inhibitory concentration (MIC) for 4 years in enterococci isolates. In the study, 2898 enterococci isolates from clinical specimens in the microbiology laboratory from 2008-2011 were evaluated retrospectively. The identification and antimicrobial susceptibility of the isolates were studied in Phoenix (BD, USA) automated system. MIC50 and MIC90 of the isolates were determined. The distribution of specimens were as follows; 60.6% urine, 18.8% blood, 11.7% wound, 5.7% sterile body fluids, and 3% catheter tips. The resistance rates were for ampicillin, vancomycin, teicoplanin, linezolid, high level gentamicin (HLG) and high level streptomycin (HLS) were determined as: 46%, 14.4%, 15.1%, 1.3%, 44.7%, and 56.5% respectively. MIC50 of the linezolid was determined as 2 mu g/ml for four years and MIC90 was determined as 4 mu g/ml for 2008, 2009, 2010 and 2 mu g/ml for 2011. MIC50 of the ampicillin was determined as 4 mu g/ml for 2008 and 2011 and 2 mu g/ml for 2009 and 2011; MIC90 was determined as 16 mu g/ml for four years. MIC50 value of vancomycin was not changed for four years and determined as 1 mu g/ml; MIC90 was determined as 32 mu g/ml for 2008, 2010, 2011 and 8 mu g/ml for 2009. MIC50 value for teicoplanin was determined as 1 mu g/ml for four years; MIC90 was determined as 2 mu g/ml for 20096 and 32 mu g/ml for other years. In the MIC values of vancomycin significance decrease was seen in 2009 (p<0.001) but after this year a significant increase (p<0.001) was determined. In the MIC values of linezolid a significant increase was determined in 2009 and 2010. A significant decrease, however, was seen in 2011

In vitro effect of tigecycline against Mycobacterium tuberculosis and a review of the available drugs for tuberculosis

The study aimed to investigate the effectiveness of a novel antibiotic drug tigecycline on clinical isolates of Mycobacterium tuberculosis and, reviewing defined anti-tuberculosis effects of available agents. Minimal inhibitory concentration (MIC) of tigecycline for 50 M. tuberculosis including multidrug-resistant (MDR) clinical isolates (20 MDR isolates) was determined by broth microdilution method in the study. Tigecycline MIC values were ranging between 8 and 64 mu g/ml. However, there is not any defined break point for M. tuberculosis resistance. In conclusion, it seems that the in vitro effectiveness of tigecycline to M. tuberculosis is not good but further in vivo studies are needed

INVESTIGATION OF BIOFILM FORMATION AND RELATIONSHIP WITH GENOTYPE AND ANTIBIOTIC SUSCEPTIBILITY OF PSEUDOMONAS AERUGINOSA STRAINS ISOLATED FROM PATIENTS WITH CYSTIC FIBROSIS

Pseudomonas aeruginosa is a frequent cause of respiratory infections in cystic fibrosis (CF) patients. P.aeruginosa strains isolated from these patients have often a mucoid phenotype at advanced disease. This mucoid structure contains a dense amount of alginate type polysaccharide which facilitates bacterial attachment to lung epithelia and provides protection from the immune system due to biofilm formation. The aims of this study were to investigate the biofilm formation and the relation of this property with genotype and antibiotic susceptibilities of P.aeruginosa strains isolated from CF patients. The biofilm formation was determined by using the Congo Red agar and Christensen methods. RAPD-PCR (Random amplification of polymorphic DNA polymerase chain reaction) and disc diffusion methods were used for genotyping and antibiotic susceptibility testing, respectively. Biofilm production was found positive in 33.3% (20/60) of P.aeruginosa tested. While 9 of these 20 isolates were of mucoid colony morphotype, among the 40 biofilm negative isolates mucoid colony was detected in 16 of them. RAPD genotyping based on 70% similarity yielded 19 (A-S) clusters and subtypes related to five of these clusters (K1, K2, N1, N2, Q1, Q2, R1, R2, S1, S2) making up a total of 24 genotypes. Nine of these genotypes composed of biofilm positive isolates and 15 were biofilm negative ones. Most of the biofilm positive strains belonged to K1 (n = 5) and K2 (n = 6) genotypes while biofilm negative isolates were in the L (n = 8) and O (n = 7) genotypes. The comparison of antibiotic susceptibilities in both groups revealed no statistically significant difference (p > 0.0%). However, highest rate of resistance was detected for tobramycin and lowest rate for piperacillin/tazobactam. The data obtained from this study indicated that biofilm negative and positive P.aeruginosa isolates clustered in different groups. These results should be supported with larger scale multi-center studies which may provide information about P.aeruginosa dynamics in CF lungs

Evaluation of Rapid Antigen Test Results and Real-time Reverse Transcription Polymerase Chain Reaction for the Laboratory Diagnosis of SARS-CoV-2

Introduction: Real-time reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard method for the diagnosis of Severe acute respiratory syndrome-Coronavirus-2 (SARS-CoV-2) infection. However, real-time RT-PCR is time-consuming, expensive, and requires special laboratory conditions and experienced personnel. Thus, the diagnostic importance of faster and easier-to-perform antigen-detecting rapid diagnostic tests (Ag-RDTs) has increased. With on-site application and fast turnaround time, Ag-RDTs provide quick isolation, minimizing the risk of transmission. We aimed to compare the results of the Mö-Screen Corona Antigen Test (MöLab, Langenfeld, Germany) and real-time RT-PCR. Materials and Methods: Nasopharyngeal swabs from 863 patients from January 2022 to March 2022 were included in the study. The SARS-CoV-2 antigen was assessed for using the Mö-Screen Corona Antigen Test. The SARS-CoV-2 real-time RT-PCR results were obtained within two days in 417 patients. Results: The agreeability of the real-time RT-PCR and Ag-RDT results was 96.2%. The sensitivity and specificity of Ag-RDT were 84.8% and 100%, respectively. The test sensitivity increased to 92% in specimens with Ct value <25. Conclusion: The Mö-Screen Corona Antigen Test (MöLab, Langenfeld, Germany), an Ag-RDT test with a high specificity and sensitivity, may be an alternative to real-time RT-PCR for the diagnosis of SARS-CoV-2

Multicenter evaluation of AYC.2.2 agar for the isolation of mycobacteria from clinical samples

Purpose: The aim of this multicenter study is to evaluate AYC.2.2 agar for the isolation of mycobacteria from clinical samples

Comparison of a novel antigen detection test with reverse transcription polymerase chain reaction assay for laboratory diagnosis of SARS-CoV-2 infection

Molecular diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by real-time reverse transcription polymerase chain reaction (RT-PCR) in respiratory specimens is considered the gold standard method. This method is highly sensitive and specific but it has some limitations such as being expensive and requiring special laboratory equipment and skilled personnel. RapidFor (TM) Antigen Rapid Test Kit is a commercially available Ag-RDT which is produced in Turkey and designed to detect the nucleocapsid antigen of SARS-CoV-2 in nasopharyngeal swab samples. The aim of this study was to evaluate the performance of this novel SARS-CoV-2 antigen detection considering the RT-PCR method as the gold standard. Four hundred forty-four nasopharyngeal swab samples which were collected from the patients who met clinical criteria of COVID-19 from ten centers in Turkey between September 2020 and February 2021 were included in the study. All the nasopharyngeal swab samples were tested for SARS-CoV-2 RNA using commercial RT-PCR kits (Bioeksen and A1 Lifesciences, Istanbul, Turkey) according to the manufacturer's instructions. Viral loads were assessed according to the cycle threshold (Ct) values. RapidFor (TM) SARS-CoV-2 antigen test (Vitrosens Biotechnology, Istanbul, Turkey) was used to investigate the presence of SARS-CoV-2 antigen in all samples following the manufacturer's instructions. Out of 444 nasopharyngeal swab samples tested, 346 (77.9%) were positive and 98 (22.1%) were negative for SARS-CoV-2 RNA by RTPCR. Overall sensitivity of the RapidFor (TM). Antigen Rapid Test Kit was 80.3% whereas specificity was found to be 87.8%. Positivity rate of rapid antigen test in samples with Ct values over 25 and below 30 was 82.7%, while it increased to 95.7% in samples 20 <= Ct < 25 and reached 100% in samples with Ct values below 20. RapidFor (TM) SARS-CoV-2 Ag test might be a good choice in the screening of symptomatic and asymptomatic patients and their contacts for taking isolation measures early, with advantages over RT-PCR as being rapid, easy and being applicable in every laboratory and even at point of care