Investigation of Torque Teno Virus (TTV) DNA as an immunological and virological marker in pediatric hematopoietic stem cell transplantation (HSCT) patients.

BACKGROUND: High viral loads are observed in Torque Teno Virus (TTV) infection after hematopoietic stem cell transplantation (HSCT). We aimed to analyze the kinetics of plasma TTV-DNA load in pediatric patients who received immunosuppressive therapy and developed infection complications in the first 100 days after HSCT. METHODS: As a patient group; 113 plasma samples taken from 33 pediatric HSCT recipients at a time interval after transplantation and as a control group; 38 plasma samples from 38 children without known chronic disease were included in the study. Viral nucleic acid isolation was performed by using the NucliSENS easyMAG (bioMerieux, France) system. A laboratory designed quantitative polymerase chain reaction process was performed on 7300 Real-Time PCR system (Applied Biosystems, CA, USA) with the amplification mixture containing primer and probe sequences for the UTR gene region. RESULTS: TTV-DNA was detected in all patient's samples and the median viral load was calculated as 7.67 Log10 copies/mL (range: 2.84-9.59). In the control group, the TTV-DNA median viral load was calculated as 5.51 Log10 copies/mL (range: 2.50-7.04), except for one negative sample. A significant difference was observed between the control group and the patient group in terms of TTV viral load levels. In nine patients, a median 2.15 Log10 copies/mL viral load increase was observed at 31-60 days post-transplant compared to the pre-transplant period. CONCLUSION: TTV-DNA levels should be closely monitored to understand the immune status of the first 100 days after transplantation and the effects of treatment regimens on patients with HSCT.

Evaluation of a chromogenic medium for detection of extended-spectrum-beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae strains.

BACKGROUND: Because of the emergence and spread of extended-spectrum-beta-lactamase (ESBL)-producing strains which are resistant to many antibiotics, reliable detection of ESBL is very important for infection control. Several chromogenic media have been proposed for the detection of ESBL producers in addition to the conventional phenotypic and genotyping methods. The aim of the present study was to evaluate the performance of Brilliance ESBL agar (Oxoid; Thermo Fisher Scientific, UK), a selective chromogenic agar for the detection of ESBL-producing Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) strains. METHODS: A total of 237 strains (143 ESBL producers (76 isolates of E. coli and 67 isolates of K. pneumoniae) and 94 non-ESBL producers (44 isolates of E. coli and 50 isolates of K. pneumoniae)) isolated from various clinical specimens were included in the study. Isolates were identified by conventional methods, Phoenix system (Becton Dickinson, USA), and mass spectrometry. ESBL confirmation was performed by phenotypical tests. A 10 microL aliquot of each isolate's 0.5 McFarland suspension was streaked onto Brilliance ESBL agar. All plates were incubated at 37 degrees C for 24 hours and then were interpreted for growth and colony color according to the manufacturer's recommendations. Identification and ESBL test results were used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the medium evaluated at 24 hours. RESULTS: The sensitivity, specificity, PPV, and NPV of the medium were 97.9%, 100%, 100%, and 96.9%, respectively, when considering only species specific colored colonies of the isolates. CONCLUSIONS: Brilliance ESBL agar could provide a practical alternative to the traditional methods for the identification of ESBL producers.