Temporal Changes in Linezolid Minimum Inhibitory Concentration Values in Vancomycin-resistant Enterococci and Methicillin-resistant Staphylococcus aureus Strains

WOS: 000511368300006Introduction: Vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) infections are among the most common Gram-positive nosocomial infections. These isolates are resistant to most antibiotics, limiting the antibiotic options that can be used in treatment and causing treatment failure. Linezolid is an important option in the treatment of resistant Gram-positive infections, and came into use in Turkey in 2006. Linezolid-resistant Enterococci and Staphylococcus strains are rarely reported worldwide. The aim of this study was to investigate whether there was an increase in linezolid minimum inhibitory concentration (MIC) values in VRE and MRSA isolates over time. Materials and Methods: Thirteen VRE and 20 MRSA isolates from 2005-2009 (group 1), 18 VRE and 20 MRSA isolates from 2013-2014 (group 2), and seven VRE and 27 MRSA isolates from 2017-2018 (group 3) obtained from various clinical samples at Kocaeli University Medical Faculty Hospital were included in the study. The linezolid MIC values of the isolates were determined by broth microdilution method. The results were interpreted according to the European Committee on Antimicrobial Susceptibility Testing standards. Results: All of the VRE and MRSA isolates were susceptible to linezolid. Linezolid MIC50 and MIC90 values were 2 mg/l in VRE isolates in all three groups. In MRSA isolates, MIC50 was 2 mg/l in group 1, and 4 mg/l in groups 2 and 3, while MIC90 was 4 mg/l in all groups. Conclusion: Global rates of linezolid resistance has been reported to be <1% for S. aureus and VRE. There were no linezolid-resistant isolates in this study. However, we detected a significant increase in MIC50 and MIC90 values compared to most earlier studies performed in Turkey. This increase is expected due to the widespread use of linezolid over the years. The principles of rational antibiotic use should be applied to maintain the low resistance rates to linezolid, which is one of the few remaining options for the treatment of multidrug-resistant Gram-positive infections

Distribution of virulence determinants among Escherichia coli ST131 and its H30/H30-Rx subclones in Turkey

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading pathogen in urinary tract infection. In recent years multidrug-resistant B2-ST131 E. coli clonal group has disseminated worldwide. The ST131 and its subclones H30 and H30-Rx have been identified only in a few studies from Turkey. The aim of this study is to investigate the presence of ST131 and its subclones and to analyze their adhesin virulence genes and antimicrobial resistance. A total of 250 urinary ExPEC isolates were included in the study. Resistance rates of 16 antimicrobial agents were determined by disk-diffusion. Multidrug-resistance and ESBL production were analyzed. Altogether 8 adhesin genes were investigated namely, papAH, fimH, sfa/focDE, focG, afa/draBC, iha, bmaE and gafD. A total of 39 ST131 isolate were determined and 33 (84.6%) were multidrug-resistant. ESBL production was detected in 34 (87.2%) ST131 and 61 (28.9%) of non-ST131 strains. In our study, we found a strong correlation between ST131 strains and fimH, iha, afa/draBC, papAH virulence determinants. Twenty-nine (85.3%) of 34 ST131-O25b-H30 isolates were identified as H30-Rx. All the papAH gene positive isolates were identified within ST131-O25b-H30-Rx lineage. Non-H30-Rx isolates within H30 isolates were identified as pattern 2. Almost 16% of the isolates were identified as ST131 regardless of clinical syndrome and approximately 34% of the multidrug-resistant isolates were H30-Rx subclone. We report H30-Rx as the dominant subclone of ST131 in our study. Imipenem, fosfomycin and nitrofurantoin proved to be the most effective agents according to antibiotic resistance patterns of both ST131 and non-ST131 E. coli strains

The schizophrenia and Toxoplasma gondii connection: Infectious, immune or both?

Introduction: Recent research has suggested a possible link between toxoplasmic agents and schizophrenia. We aimed to assess this by measuring Toxoplasma gondii-associated antibodies in schizophrenia patients and controls

Automated labelling of cancer textures in colorectal histopathology slides using quasi-supervised learning

OBJECTIVE: To evaluate the performance of a quasisupervised statistical learning algorithm, operating on datasets having normal and neoplastic tissues, to identify larynx squamous cell carcinomas. Furthermore, cancer texture separability measures against normal tissues are to be developed and compared either for colorectal or larynx tissues

Investigation of Carbapenemases in Carbapenem-Resistant Escherichia coli and Klebsiella pneumoniae Strains Isolated in 2014 in Turkey

Carbapenems are the choice of treatment in infections caused by multidrug resistant Enterobacteriaceae. In recent years carbapenem-resistant Enterobacteriaceae isolates due to carbapenemases have been increasingly reported worldwide. Multicenter studies on carbapenemases are scarce in Turkey. The aim of this study was to determine the distribution of carbapenemases from different parts of Turkey as a part of the European Survey of Carbapenemase Producing Enterobacteriaceae (EuSCAPE) project. Beginning in November 2013, carbapenem-resistant isolates resistant to at least one of the agents, namely imipenem, meropenem, and ertapenem were sent to the coordinating center. Minimum inhibitory concentrations for these carbapenems were determined by microdilution tests following EUCAST guidelines. Production of carbapenemase was confirmed by combination disk synergy tests. Types of carbapenemases were investigated using specific primers for VIM, IMP; NDM, KPC and OXA-48 genes by multiplex polymerase chain reaction. In a six month period, 155 suspected carbapenemase-positive isolates were sent to the coordinating center of which 21 (13.5%) were E.coli and 134 (86.5%) were K.pneumoniae. Nineteen (90.5%) strains among E.coli and 124 (92.5%) strains among K.pneumoniae were shown to harbour at least one carbapenemase gene by molecular tests, with a total of 92.3% (143/155). Carbapenemases were determined as a single enzyme in 136 strains (OXA-48: 84.6%; NDM: 6.3%; VIM: 2.8%; IMP: 1.4%) and as a combination in seven isolates (OXA-48 + NDM: 2.1%; OXA-48 + VIM: 2.1%; VIM + NDM: 0.7%). KPC was not detected in any of the isolates. According to the microdilution test results, resistance to imipenem, meropenem and ertapenem in OXA-48 isolates were 59.5%, 52.9% and 100%, respectively. The combination disk synergy test was 100% compatible with the molecular test results. As most of the OXA-48 producing isolates were susceptible to meropenem but all were resistant to ertapenem, ertapenem seems to be the most sensitive agent in screening carbapenemases in areas where OXA-48 is prevalent and phenotypic combination tests can be useful in centers where molecular tests are not available.Wo