Derya Keten

Publications (3) View all

• Article: Susceptibility to Teicoplanin among Coagulase-Negative Staphylococci Isolated from Catheter Related Bloodstream Infections in Febrile Neutropenic Patients

  Güzel-Tunçcan Özlem, Tozlu-Keten Derya, Dizbay Murat, Şenol Esin
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  ABSTRACT: Objective: Catheter related bloodstream infections (CRBSI) caused by coagulase-negative staphylococci (CNS) are frequent in patients with febrile neutropenia (FN) and glycopeptides are used empirically in the treatment of these infections. Recently, decreased susceptibility to teicoplanin among CNS has been reported, especially in Staphylococcus haemolyticus and S. epidermidis, due to excessive use of glycopeptides. In this study, we aimed to determine the minimal inhibitor concentrations (MICs) of teicoplanin and to compare its activity with other antibiotics on CNS isolated from CRBSI in patients with hematological malignancies and hematopoietic stem cell transplantation.Methods: The study was performed on CNS strains isolated from CRBSI of FN patients during the period between 2007 and 2009. Susceptibility to oxacillin was tested by disk diffusion method, and teicoplanin MICs were determined by using E-test® method.Results: A total of 96 CNS strains causing CRBSI, isolated from different FN attacks of 39 patients were analyzed. Among them, S. epidermidis (46%) and S. haemolyticus (39%) were the most frequent CNS species. Although teicoplanin resistance was not detected in the CNS isolates, 10% of the isolates revealed decreased susceptibility to teicoplanin. Teicoplanin MICs and methicillin resistance rates were found to be statistically higher among S. haemolyticus strains than those of S. epidermidis. Conclusions: CNS isolated from CRBSI in FN patients should be identified to the species level, and the change of therapy in case of clinical failure should be made according to the MICs of antibiotics. Teicoplanin MICs among CNS, especially in S. haemolyticus, should be closely monitored.
  Klimik Journal. 01/2010;
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  Available from: Selma Tosun

  Article: Assessment of the requisites of microbiology based infectious disease training under the pressure of consultation needs.

  Hakan Erdem, Suda Tekin-Koruk, Ibrahim Koruk, Derya Tozlu-Keten, Aysegul Ulu-Kilic, Oral Oncul, Rahmet Guner, Serhat Birengel, Gurkan Mert, Saygin Nayman-Alpat, [......], Asim Ulcay, Halil Kurt, Bulent A Besirbellioglu, Haluk Vahaboglu, Yesim Tasova, Gaye Usluer, Dilek Arman, Husrev Diktas, Sercan Ulusoy, Hakan Leblebicioglu
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  ABSTRACT: Training of infectious disease (ID) specialists is structured on classical clinical microbiology training in Turkey and ID specialists work as clinical microbiologists at the same time. Hence, this study aimed to determine the clinical skills and knowledge required by clinical microbiologists. A cross-sectional study was carried out between June 1, 2010 and September 15, 2010 in 32 ID departments in Turkey. Only patients hospitalized and followed up in the ID departments between January-June 2010 who required consultation with other disciplines were included. A total of 605 patients undergoing 1343 consultations were included, with pulmonology, neurology, cardiology, gastroenterology, nephrology, dermatology, haematology, and endocrinology being the most frequent consultation specialties. The consultation patterns were quite similar and were not affected by either the nature of infections or the critical clinical status of ID patients. The results of our study show that certain internal medicine subdisciplines such as pulmonology, neurology and dermatology appear to be the principal clinical requisites in the training of ID specialists, rather than internal medicine as a whole.
  Annals of Clinical Microbiology and Antimicrobials 12/2011; 10:38. · 2.64 Impact Factor
• Article: In vitro synergistic activity of tigecycline and colistin against XDR-Acinetobacter baumannii

  Murat Dizbay, Derya Keten Tozlu, Meltem Yalinay Cirak, Yasemin Isik, Kevser Ozdemir, Dilek Arman
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  ABSTRACT: The emergence of extensive drug-resistant (XDR) Acinetobacter baumannii limits the therapeutic options and leads to high mortality in intensive care units. Combined antibiotic therapy is frequently recommended for the treatment of these infections. Colistin (CO) and tigecycline (TIG), alone or in combination with other antimicrobials, are the most commonly used antibiotics in the treatment of these resistant infections. In this study, the in vitro synergistic activity of TIG and CO were tested for 25 XDR-A. baumannii strains isolated from ventilator-associated pneumonia by the Etest method. Resistance to CO was not detected, whereas 8% of the strains were resistant to TIG. The TIG–CO combination was more synergistic than TIG–rifampin and CO–rifampin according to the fractional inhibitory concentration index. No antagonism was detected between the drugs in the study. There was no strong correlation between the activity of the combinations with reference to strains or genotypes. Our results suggest that the combined use of TIG and CO may be useful for the treatment of XDR-A. baumannii infections.Keywords: Acinetobacter baumannii, colistin, combination, rifampin, synergy, tigecycline
  The Journal of Antibiotics 11/2009; 63(2):51-53. · 1.65 Impact Factor