Browsing by Author "Aydin, Merve"

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Absence of the Mecc Gene in Methicillin-Resistant Staphylococcus Aureus Isolated From Various Clinical Samples: the First Multi-Centered Study in Turkey
(Elsevier Science London, 2019) Cikman, Aytekin; Aydin, Merve; Gulhan, Baris; Karakecili, Faruk; Kurtoglu, Muhammet G.; Yuksekkaya, Serife; Ozekinci, Tuncer
Background: mecA is a predefined gene causing methicillin resistance in Staphylococcus aureus (S. aureus) isolates; however, it has been shown that some methicillin-resistant S. aureus (MRSA) strains do not carry this gene. Recently, in isolates found to be MRSA-positive but mecA-negative, a new resistance gene called mecC, which is a homolog of mecA, has been reported. This study aimed to investigate the mecC and mecA genes in MRSA strains isolated from different geographic regions in Turkey. Methods: The sample of the study consisted of 494 MRSA strains isolated from seven geographical regions in Turkey between 2013 and 2016. The strains were obtained from 17 centers, comprising 13 university hospitals, three education and research hospitals, and one state hospital. Methicillin resistance in S. aureus strains was determined using the agar disk diffusion method with a cefoxitin disk and the agar dilution method with oxacillin. The mecC and mecA genes in MRSA strains was investigated by Polymerase Chain Reaction (PCR). Results: Of the MRSA strains investigated, 47.9% were isolated from intensive care units. Concerning sample type, 36.7% were detected in the respiratory tract (tracheal aspirate, sputum, etc.), 24.8% in blood, 18.7% in skin and soft tissues, 9.3% in nasal swabs, 5.4% in urine, 4.1% in ears, and 1% in sterile body fluid. Using PCR, mecC was not identified in any of the S. aureus strains isolated from different clinical microbiology laboratories. mecA gene positivity was found in 315 of the MRSA strains (63.8%). Staphylococcal Cassette Chromosome mec ( SCCmec) type was identified in 232 strains (46.9%), of which 136 (58.7%) were type II, 75 (32.4%) were type IV, 12 (5.1%) were type Mb, six (2.5%) were type I, and three (1.3%) were type III. Conclusion: This is the first multi-centered study to investigate MRSA strains isolated from different regions in Turkey. The mecC gene was not detected in any of the MRSA strains. We believe that this study will constitute an important basis for monitoring possible future changes. (C) 2019 The Authors. Published by Elsevier Limited on behalf of King Saud Bin Abdulaziz University for Health Sciences.
In Vitro Activity of Colistin in Combination With Tigecycline Against Carbapenem-Resistant Acinetobacter Baumannii Strains Isolated From Patients With Ventilator-Associated Pneumonia
(Ivyspring int Publ, 2015) Cikman, Aytekin; Gulhan, Baris; Aydin, Merve; Ceylan, Mehmet Resat; Parlak, Mehmet; Karakecili, Faruk; Karagoz, Alper
Objective: This study investigated the minimum inhibitory concentration (MIC) values and in vitro activity of colistin in combination with tigecycline against carbapenem-resistant Acinetobacter baumannii strains isolated from patients with ventilator-associated pneumonia (VAP) using the E-test method. Methods: A total of 40 A. baumannii strains, identified using the Phoenix Automated Microbiology System (Becton, Dickinson and Co., Franklin Lakes, NJ, USA) by conventional methods, were included in this study. Pulsed-field gel electrophoresis was performed to examine the clonal relationships between isolates. The carbapenem resistance of the strains to colistin and tigecycline was assessed using the E-test method (Liofilchem, Roseto Degli Abruzzi, Italy). The in vitro activity of colistin in combination with tigecycline was evaluated using the fractional inhibitor concentration (FIC) index. Results: While only 1 of 40 A. baumannii strains was determined to be colistin resistant, 6 were tigecycline resistant. The MIC50, MIC90, and MIC intervals of the A. baumannii strains were 0.19, 1.5, and 0.064-4 mu g/ml for colistin and 1, 8, and 0.094-256 mu g/ml for tigecycline, respectively. No synergistic effect was observed using the FIC index; 8 strains exhibited an indifferent effect and 32 exhibited an antagonist effect. Three of the six strains that were resistant to tigecycline were indifferent; the remaining three were antagonistic. The colistin-resistant strain also exhibited an antagonist effect. Conclusion: In contrast to their synergistic effect against carbapenem-resistant A. baumannii isolates, colistin and tigecycline were highly antagonistic to carbapenem-resistant A. baumannii strains isolated from patients with VAP when the drugs were administered together. Therefore, alternative treatment options should be used during the treatment of VAP attributed to A. baumannii.
Investigation of Antibiotic Resistance Patterns and Reduced Vancomycin Susceptibilities of Methicillin-Resistant Staphylococcus Aureus Isolates: a Multi-Center Study
(Ankara Microbiology Soc, 2015) Cikman, Aytekin; Aydin, Merve; Gulhan, Baris; Parlak, Mehmet; Gultepe, Bilge; Kalayci, Yildiz; Ozekinci, Tuncer
The aims of this study were to determine the minimum inhibitory concentration (MIC) values of vancomycin, teicoplanin, daptomycin, quinupristin/dalfopristin, linezolid, tigecycline, chloramphenicol, rifampicin, ofloxacin and tetracycline and to investigate the reduced vancomycin susceptibility among methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in hospitals located in different geographical regions of Turkey. A total of 100 MRSA strains isolated from patients (of which 50% were from intensive care units) hospitalized in seven centers in Turkey [Istanbul (n= 15), Ankara (n= 15), Izmir (n= 15), Adana (n= 15), Diyarbakir (n=15), Erzincan (n= 15), Van (n= 10)], between August 201 3 August 2014, were included in the study. Fourty-three strains were isolated from blood, whereas 21 were from lower respiratory tract, 17 from wounds, eight from catheters, six from urine, four from nasal swab and one from cerebrospinal fluid samples. Methicillin resistance of the isolates was determined by using cefoxitin (30 mu g) disk with standard disk diffusion method, while the MIC values of other antibiotics were determined with E-test in accordance with the recommendations of Clinical and Laboratory Standards Institute (CLSI). MIC results obtained for quinupristin-dalfopristin (Q/D) were evaluated according to the CLSI criteria used for methicillin-susceptible S.aureus and for tigecycline according to the criteria recommended by the Food and Drug Administration for MRSA. Primarily, agar screening method (ASM) was used for determination of vancomycin-intermediate S.aureus (VISA) and heterogeneous VISA (hVISA) strains. Brain heart infusion agar containing 6 mu g/ml vanconnycin was used in ASM, and the strains with suspicion of VISA/hVISA were screened by standard E-test and macro E-test methods. All MRSA strains were susceptible to vancomycin, teicoplanin, daptomycin, Q/D and linezolid by E-test method; and their rates of susceptibility for tigecycline, chloramphenicol, rifampicin, ofloxacin and tetracycline were detected as 89%, 97%, 40%, 39% and 32%, respectively. MIC50/MIC90 values were 1.5/2 mu g/ml for vancomycin, 2/4 mu g/ml for teicoplanin, 0.19/0.38 mu g/ml for daptomycin, 0.19/0.38 mu g/ml for Q/D, 0.75/1 mu g/ml for linezolid, 0.19/0.75 mu g/ml for tigecycline, 3/6 mu g/ml for chloramphenicol, 32/32 mu g/ml for rifampicin, 32/32 mu g/ml for ofloxacin and 32/64 mu g/ml for tetracycline, respectively. For the evaluation of reduced vancomycin susceptibility, 2% (2/100) of MRSA strains were defined as VISA and 5% (5/100) as hVISA with ASM. One of those seven isolates identified as VISA/hVISA with ASM was evaluated as suspected hVISA by using both standard E-test and macro E-test methods. In conclusion, no MRSA resistant strain to vancomycin, teicoplanin, daptomycin, Q/D and linezolid was determined in our study. However tigecycline resistance (11%) was found higher than expected. As the glycopeptide resistance is increasing in the world and because of the intense use of these drugs in Turkey, the rates of vancomycin resistance among MRSA strains should be investigated periodically.
The Seroprevalence of Coxiella Burnetii in Erzincan, Turkey: Identification of the Risk Factors and Their Relationship With Geographical Features
(Wolters Kluwer Medknow Publications, 2017) Cikman, Aytekin; Aydin, Merve; Gulhan, Baris; Karakecili, Faruk; Ozcicek, Adalet; Kesik, Ozan Arif; Gultepe, Bilge
Background & objectives: Coxiella burnetii (C. burnetii) bacterium, the causative agent of Q fever has regained importance due to the increasing cases of infections and outbreaks. A cross-sectional descriptive study was conducted to investigate the seroprevalence of C. burnetii in human populations of Erzincan province located in the eastern Turkey, identify the risk factors, and to explore the relationship between geographical features. Methods: A total of 368 people residing in the rural (306) and urban (62) areas of the province were included in the study. Serum samples were analyzed for the presence of C. burnetii phase II IgG antibody using ELISA (Virion/Serion, Wurzburg, Germany). Spatial analyses were performed to evaluate correlations between seroprevalence and geographical features. Results: The overall seroprevalence of C. burnetii was found to be 8.7% (32/368). In rural residents it was 8.5% (26/306), while in urban population it was 9.7% (6/62). Cattle breeding and contact with animal afterbirth waste were found to be major risk factors, and were significantly correlated with seropositive cases (p < 0.05). The seropositive cases were only observed in the areas between 1067 and 1923 masl. Of the total seropositive cases, 65.6% were within 1000 m and 87.5% within 4000 m of rivers and their main tributaries. Around 59.4% cases were observed in areas with a slope of 0 to 5 degrees. Interpretation & conclusion: The results of the study showed that C. burnetii seroprevalence was higher than expected, and significantly differs according to geographical features of a region. Significant risk factors include raising cattle and exposure to infected animals or their birth products/secretions. It is also more frequent in areas with higher number of rivers and streams, higher altitude and lower slope.