Browsing by Author "Çoban A.Y."

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    T030 is the most common spa type among methicillin-resistant staphylococcus aureus strains isolated from Turkish hospitals; [T030, Türkiye'deki hastanelerden izole edilen metisiline dirençli staphylococcus aureus izolatlari arasinda en yaygin spa tipidir]
    (Ankara Microbiology Society, 2013) Bozdoǧan B.; Yildiz Ö.; Oryaşin E.; Kirdar S.; Gülcü B.; Aktepe O.; Arslan U.; Bayramoǧlu C.; Çoban A.Y.; Coşkuner S.A.; Güdücüoǧlu H.; Karablber N.; Öncü S.; Tatman Otkun M.; Özkütük N.; Özyurt M.; Şener A.G.
    Staphylococcus aureus is one of the most frequent agents causing hospital infections. S.aureus has a great ability to adapt itself to variety of conditions and successful clones can be epidemic and even pandemic by its ability spread from one continent to another. The aims of this study were to detect spa types of 397 methicillin-resistant S.aureus (MRSA) strains isolated from 12 centers in different geographical regions of Turkey from 2006 to 2008, and to investigate their clonality by PFCE and MLST typing. Additionally, 91 MRSA from four of those 12 centers isolated during 2011 were also studied for their spa types. PFGE profiles indicated the presence of a major pulsotype, namely pulsotype A with a rate of 91.4% (363/397), followed by pulsotype B (n= 18, 4.5%) and pulsotype C (n= 11, 2.8%). Among isolates tested 363 (91.4%) were SCCmec type III, 30 (7.6%) were SCCmec type IV. Sequence analysis of representative isolates revealed that ST239 (85.1%) was the most common MLST type followed by two MLST types ST737 (4%), and ST97 (2.8%), both SCCmec type IV. Two isolates were ST80 with SCCmec type IV. Of 397 isolates, 338 (85.1%) were t030, followed by t005 (2.5%) and t632 (2%). Among MRSA isolated during 2011, 64 (70.3%) of 91 were t030, 4 (4.4%) were tOOS, 2 (2.2%) were t015, and 2 (2.2%) were t1094. Among centers the t030 prevalence of 2006-2008 isolates ranged from 59-100%. The highest t030 prevalence was found in Ankara (100%) and lowest in Trabzon (59%) provinces which are located at central and northestern Anatolia, respectively. In Istanbul province, the prevalence of t030 was 94.5% among 2006-2008 isolates which decreased to 55.5% among 2011 isolates. Also a decrease in t030 rates was observed among samples from Konya and Trabzon but not from Aydin. Our results showed that the most common MRSA clone in Turkey is ST 239-SCCmec type III, t030 which persisted during the six years of the study period. Presence of PVL toxin gene was tested by PCR and 5 (3%) isolates found to be positive, of them two were SCCmec Type IV-ST80 and three were SCCmec Type III-ST239. This study is the largest epidemiological survey ever done in Turkey which showed presence of a hospital Turkish clone TR09 (ST239-SCC meclll-t030) and a community clone TR10 (ST737-SCCmedV-t005) largely disseminated in Turkey.
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    Antimicrobial susceptibility and resistance mechanisms of methicillin resistant Staphylococcus aureus isolated from 12 Hospitals in Turkey
    (BioMed Central Ltd., 2014) Yildiz T.; Çoban A.Y.; Şener A.G.; Coşkuner S.A.; Bayramoğlu G.; Güdücüoğlu H.; Özyurt M.; Tatman-Otkun M.; Karabiber N.; Özkütük N.; Aktepe O.; Öncü S.; Arslan U.; Bozdoğan B.
    Introduction: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important nosocomial pathogens and is also emerging in Turkish hospitals. The aim of this study was to determine the antimicrobial susceptibility profiles of MRSA isolated from Turkish hospitals. Materials and methods: A total of 397 MRSA strains isolated from 12 hospitals in Turkey were included to present study. Antimicrobial susceptibilities were tested using agar dilution method. Presence of ermA, ermB, ermC, msrA, tetM, tetK, linA and aac-aph genes were studied by PCR. Results: All strains were susceptible to vancomycin and linezolid. The susceptibility rates for fusidic acid, lincomycin, erythromycin, tetracyclin, gentamycin, kanamycin, and, ciprofloxacin were 91.9%, 41.1%, 27.2%, 11.8%, 8.5%, 8.3% and 6.8%, respectively. Lincomycin inactivation was positive for 3 isolates. Of 225 erythromycin resistant isolates 48 had ermA, 20 had ermC, and 128 had ermA-C. PCR was negative for 15 strains. Of 3 isolates with lincomycin inactivation one had linA and msrA. Of 358 gentamycin resistant isolates 334 had aac-aph and 24 were negatives. Among 350 tetracyclin resistant isolates 314 had tetM. Of 36 tetM negative isolates 10 had tetK. Conclusion: MRSA isolates from Turkish hospitals were multiresistant to antimicrobials. Quinolone and gentamycin resistance levels were high and macrolide and lincosamide resistance were relatively low. Susceptibility rates for fusidic asid were high. Linezolide and vancomycin resistance are not emerged. The most common resistance genes were ermA, tetM and aac-aph. Evolution of antimicrobial susceptibilities and resistance genes profiles of MRSA isolates should be surveyed at regional and national level for accurate treatment of patients and to control dissemination of resistance genes. © 2014 Yildiz et al.; licensee BioMed Central Ltd.
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    Multicentef evaluation of the indirect nitrate reductase assay for the rapid detection of multidrug-resistant tuberculosis; [Çok ilaca dirençli tüberkulozun hizli tespiti için dolayli nitrat redüktaz testinin çok merkezli deǧerlendirilmesi]
    (Ankara Microbiology Society, 2016) Çoban A.Y.; Taştekin B.; Uzun M.; Kalayci F.; Ceyhan I.; Biçmen C.; Albay A.; Siǧ A.K.; Özkütük N.; Sürücuoglü S.; Ozkütük A.; Esen N.; Albayrak N.; Aslanturk A.; Saribaş Z.; Alp A.
    Multidrug-resistant tuberculosis (MDR-TB) is defined as resistance to at least isoniazid (INH) and rifampicin (RIF), and it complicates the implementation of tuberculosis control programmes. The rapid detection of MDR-TB is crucial to reduce the transmission of disease. The nitrate reductase assay (NRA) is one of the colorimetric susceptibility test methods for rapid detection of MDR-TB and based on the ability of reduction of nitrate to nitrite by Mycobacterium tuberculosis. The aim of this study was to evaluate the performance of the NRA for the rapid detection of MDR-TB. A total of 237 M.tuberculosis complex (MTC) isolates that were identified by the same method (BD MGIT™ TBc Identification Test, USA) from nine different medical centers in Turkey were included in the study. The susceptibility results of the isolates against INH and RIF obtained by reference test (Bactec MGIT™ 960, BD, USA) were then compared with NRA. In order to ensure consistency between centers, Lowenstein-jensen (Lj) medium with antibiotics and without antibiotics (growth control) and Griess reagent solution were prepared in a single center (Ondokuz Mayis University School of Medicine, Medical Microbiology Department) and sent to all participant centers with the standardized test procedure. After the inoculation of bacteria into the test tubes, the tubes were incubated at 37°C, and after seven days of incubation, 500 pi Griess reagent was added to the L) medium without antibiotics. If a color change was observed, an equal volume of Griess reagent was added to test L) media with antibiotics. When a color change was observed in L) media with antibiotics, it was considered that the isolate was resistant to tested antibiotics. Among 237 MTC isolates, 16 were resistant only to INH and nine were resistant only to RIF; 93 isolates (39.2%) were resistant (MDR) and 119 isolates (50.2%) were susceptible to both of the drugs determined with the reference susceptibility test. In the study, five INH-resistant isolates determined with reference method were found susceptible with NRT and eight INH-susceptible isolates determined with reference method were found resistant with NRT. In contrast, one RIF-resistant isolate determined with reference method was found susceptible with NRT and three RIF-susceptible determined isolates were found resistant with NRT. Accordingly, the concordance rate between the reference method and NRA were estimated as 94.5% for INH and 98.3% for RIF. The sensitivity, specificity, positive and negative predictive values of NRA were detected as 95.4%, 93.7%, 92.8% and 96% for INH, and 99%, 97.8%, 97.1% and 99.2% for RIF, respectively. The results of the 111 isolates were obtained on the seventh day, while the rest of the results were obtained between 10-14 days. In conclusion, the data of this multicenter study showed that NRA is a reliable, relatively inexpensive and practical method to perform for the rapid detection of MDR-TB.