Yazar "Durmaz, Riza" seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe The characteristics of nasopharyngeal Streptococcus pneumoniae in children attending a daycare unit(Edizioni Int Srl, 2008) Abut, Latife Iseri; Apan, Teoman; Otlu, Baris; Caliskan, Ahmet; Durmaz, RizaS. pneumoniae is a component of normal nasopharyngeal flora in children. Nasopharyngeal colonization in children attending daycare units has an important effect on the spread of S. pneumoniae. In this study, we aimed to investigate colonization status, antimicrobial susceptibility, and clonal relatedness of the S. pneumoniae strains in children attending a daycare unit. One hundred and six nasopharyngeal swabs were collected from 25 children attending a daycare unit in an 8-month period. S. pneumoniae was identified by a conventional method. Antibacterial sensitivities of the strains were tested by disc diffusion method. Pulsed field gel electrophoresis (PFGE) was used to analyze the clonal relationship of the strains. A total of 25 (23.5 %) S. pneumoniae strains were identified from 106 nasopharyngeal swaps. S. pneumoniae growth was detected in at least one culture of the 19 children (colonization rate; 76%). Seven of the 25 strains (28%) showed resistance to penicillin, 5 (20%) were resistant to trimethoprim-sulfomethoxsazole. The other tested antibiotics were almost effective. The clonal relationship among strains was found as 54.5%. The highest rate of strain entry was in the winter months with strains of opaque colonies, which are known to be more pathogenic. However, the spreading rate among the children was the highest in the summer months and the strains detected in these months had transparent colonies with more transmitting characteristics. Therefore, to prevent S. pneumoniae infection in closed crowded areas, the summer months should not be overlooked.Öğe Drug resistance profiles and clonality of sporadic Shigella sonnei isolates in Ankara, Turkey(Soc Brasileira Microbiologia, 2014) Kacmaz, Birgul; Unaldi, Ozlem; Sultan, Nedim; Durmaz, RizaThe aims of this study were to investigate drug resistance rates, types of extended spectrum beta lactamases (ESBLs), and molecular epidemiological characteristics of 43 Shigella sonnei isolates. Ampicillin-sulbactam, amoxicillin-clavulanate, chloramphenicol, and ciprofloxacin were the most active antibiotics. Five isolates harbored bla(SHV-12), bla(TEM-1) and bla(CTX-M-15). More than 90% of the isolates had an indistinguishable pulsotype.Öğe Molecular Characterization of Measles Viruses in Turkey (2010-2011): First Report of Genotype D9 Involved in an Outbreak in 2011(Wiley, 2013) Kalaycioglu, Atila T.; Baykal, Atakan; Guldemir, Dilek; Bakkaloglu, Zekiye; Korukluoglu, Gulay; Coskun, Aslihan; Durmaz, RizaGenetic characterization of measles viruses (MVs) combined with acquisition of epidemiologic information is essential for measles surveillance programs used in determining transmission pathways. This study describes the molecular characterization of 26 MV strains (3 from 2010, 23 from 2011) obtained from urine or throat swabs harvested from patients in Turkey. MV RNA samples (n=26) were subjected to sequence analysis of 450 nucleotides comprising the most variable C-terminal region of the nucleoprotein (N) gene. Phylogenetic analysis revealed 20 strains from 2011 belonged to genotype D9, 3 to D4, 2 strains from 2010 to genotype D4 and 1 to genotype B3. This study represents the first report describing the involvement of MV genotype D9 in an outbreak in Turkey. The sequence of the majority of genotype D9 strains was identical to those identified in Russia, Malaysia, Japan, and the UK. Despite lack of sufficient epidemiologic information, the presence of variants observed following phylogenetic analysis suggested that exposure to genotype D9 might have occurred due to importation more than once. Phylogenetic analysis of five genotype D4 strains revealed the presence of four variants. Epidemiological information and phylogenetic analysis suggested that three genotype D4 strains and one genotype B3 strain were associated with importation. This study suggests the presence of pockets of unimmunized individuals making Turkey susceptible to outbreaks. Continuing molecular surveillance of measles strains in Turkey is essential as a means of acquiring epidemiologic information to define viral transmission patterns and determine the effectiveness of measles vaccination programs designed to eliminate this virus. J. Med. Virol. 85:2128-2135, 2013. (c) 2013 Wiley Periodicals, Inc.Öğe Monitoring Genetic Diversity of Influenza A(H1N1)pdm09 Virus Circulating during the Post-Pandemic Period in Turkey(Natl Inst Infectious Diseases, 2013) Guldemir, Dilek; Kalaycioglu, Atila T.; Altas, A. Basak; Korukluoglu, Gulay; Durmaz, RizaThe aimes of the present study were to monitor genetic alterations in the hemagglutin (HA) gene and oseltamivir resistance-related alterations in the neuraminidase (NA) gene of influenza A(H1N1)pdm09 viral isolates detected during the post-pandemic period in Turkey. A total of 2601 clinical specimens obtained from suspected cases of influenza A(H1N1)pdm09 viral infections were analyzed by real-time reverse transcription polymerase chain reaction. Viral RNA was detected in 233 (9%) clinical specimens. Sequence analysis of the HA gene in 16 random isolates showed >98.7% homology among each other and with the A/California/07/2009 vaccine strain. These 16 isolates had common (75%-100%) amino acid substitiutions at positions P83S, D97N, S203T, R205K, I216V, V249L, I321V, and E374K in the HA gene. In addition, two additional rare mutations were also observed at positions S162N (addition of a glycosylation site, 6.25%) and A186T (receptor binding region, 6.25%). On the basis of amino acid substitutions in the HA1 domain, majority of the Turkish isolates were classified in the genetic group v and others in the genetic groups ii, iii, and vi. In the present study, we observed an increase in the variety and ratio of mutations detected in the HA1. and HA2 domains of the HA gene; however, these alterations have not yet resulted in vaccine escape mutants in Turkey. In addition, analysis of the NA regions of the isolates revealed that oseltamivir resistance was not an issue in Turkey.Öğe Multiple-Locus Variable-Number Tandem-Repeat Analysis Genotyping of Human Brucella Isolates from Turkey(Amer Soc Microbiology, 2011) Kilic, Selcuk; Ivanov, Ivan N.; Durmaz, Riza; Bayraktar, Mehmet Refik; Ayaslioglu, Ergin; Uyanik, M. Hamidullah; Kantardjiev, Todor V.A multiple-locus variable-number tandem-repeat analysis (MLVA) was applied to investigate the epidemiological relationship and genetic diversity among 162 human Brucella isolates collected from all geographic regions of Turkey in an 8-year period (2001 to 2008). The isolates were genotyped by using an MLVA assay developed in Orsay, France (MLVA-16(Orsay)) including eight minisatellite (panel 1) and eight microsatellite (panel 2, subdivided into 2A and 2B) markers. Panels 1 and 2A distinguish 14 genotypes; two of these represented 85% of the strains. Panel 2B displayed a very high discriminatory power. Three loci from panel 2B had diversity index values higher than 0.74. MLVA-16(Orsay) yielded 105 genotypes; 73 were represented by a unique isolate, and 32 included two to eight isolates. The isolates from different patients within the same outbreak or from the same patient before first-line therapy and after relapse showed identical genotypes. A number of MLVA genotypes appeared to be partially restricted to some geographic areas and displayed no annual variation, possibly reflecting persistence of genotypes in certain areas for a time span of at least a decade. This study, representing the first molecular typing results of human Brucella isolates from Turkey, indicated that Turkish human Brucella melitensis isolates were most closely related to the neighboring countries' isolates included in the East Mediterranean group.Öğe One-Step Multiplex PCR Assay for Detecting Streptococcus pneumoniae Serogroups/Types Covered by 13-Valent Pneumococcal Conjugate Vaccine (PCV13)(Public Library Science, 2012) Coskun-Ari, Fatma Filiz; Guldemir, Dilek; Durmaz, RizaThe life-threatening illnesses caused by Streptococcus pneumoniae have been declined significantly after the use of pneumococcal conjugate vaccines. Continuous monitoring of the vaccine serogroups/types is necessary to follow the changing epidemiology of invasive pneumococcal diseases. Recently, the sequential multiplex PCR approach, which uses several different sets of reactions, has been commonly adopted for determining capsular serogroups/types of S. pneumoniae isolates. In our study, we focused on development of a one-step multiplex PCR assay detecting all 1, 3, 4, 5, 6A/B, 7F, 9V, 14, 18C, 19A, 19F and 23F serogroups/types targeted by PCV13. The content of multiplex PCR mix and the cycling conditions were optimized in a manner that allowed rapid and accurate serotyping of a pneumococcal isolate by performing only a single amplification reaction. In our study of 182 clinical isolates, the one-step multiplex PCR assay exhibited 100% sensitivity and specificity, suggesting that its utilization can significantly reduce the use of traditional antiserum method requiring expensive reagents. Citation: Coskun-Ari FF, Guldemir D, Durmaz R (2012) One-Step Multiplex PCR Assay for Detecting Streptococcus pneumoniae Serogroups/Types Covered by 13-Valent Pneumococcal Conjugate Vaccine (PCV13). PLoS ONE 7(12): e50406. doi:10.1371/journal.pone.0050406Öğe A prospective multicenter study on the evaluation of antimicrobial resistance and molecular epidemiology of multidrug-resistant Acinetobacter baumannii infections in intensive care units with clinical and environmental features(Bmc, 2019) Boral, Baris; Unaldi, Ozlem; Ergin, Alper; Durmaz, Riza; Eser, Ozgen Koseoglu; Zarakolu, Pinar; Sipahi, Oguz ResatBackgroundMultidrug-resistant (MDR) Acinetobacter baumannii infections are considered as emerging nosocomial infections particularly in patients hospitalized in intensive care units (ICUs). Therefore, reliable detection of MDR strains is crucial for management of treatment but also for epidemiological data collections. The purpose of this study was to compare antimicrobial resistance and the clonal distribution of MDR clinical and environmental A. baumannii isolates obtained from the ICUs of 10 different hospitals from five geographical regions of Turkey in the context of the demographic and clinical characteristics of the patients.MethodsA multicenter-prospective study was conducted in 10 medical centers of Turkey over a 6month period. A total of 164 clinical and 12 environmental MDR A. baumannii isolates were included in the study. Antimicrobial susceptibility testing was performed for amikacin (AN), ampicillin-sulbactam (SAM), ceftazidime (CAZ), ciprofloxacin (CIP), imipenem (IMP) and colistin (COL) by microdilution method and by antibiotic gradient test for tigecycline (TIG). Pulsed-field gel electrophoresis (PFGE) was performed to determine the clonal relationship between the isolates. The detection of the resistance genes, bla(OXA-23),bla(OXA-24),bla(OXA-51,)bla(OXA-58,)bla(IMP,)bla(NDM), bla(KPC), bla(OXA-48) and bla(PER-1) was carried out using the PCR method.ResultsThe mortality rate of the 164 patients was 58.5%. The risk factors for mortality included diabetes mellitus, liv1er failure, the use of chemotherapy and previous use of quinolones. Antimicrobial resistance rates for AN, SAM, CAZ, CIP, IMP, COL and TIG were 91.8%, 99.4%, 99.4%, 100%, 99.4%, 1.2% and 1.7% respectively. Colistin showed the highest susceptibility rate. Four isolates did not grow on the culture and were excluded from the analyses. Of 172 isolates, 166 (96.5%) carried bla(OXA-23), 5 (2.9%) bla(OXA-58) and one isolate (0.6%) was positive for both genes. The frequency of bla(PER-1) was found to be 2.9%. None of the isolates had bla(IMP), bla(KPC), bla(NDM) and bla(OXA-48) genes. PFGE analysis showed 88 pulsotypes. Fifteen isolates were clonally unrelated. One hundred fifty-seven (91.2%) of the isolates were involved in 14 different clusters.ConclusionsColistin is still the most effective antibiotic for A. baumannii infections. The gene bla(OXA-23) has become the most prevalent carbapenemase in Turkey. The distribution of invasive A. baumannii isolates from different regions of Turkey is not diverse so, infection control measures at medical centers should be revised to decrease the MDR A. baumannii infections across the country. The results of this study are expected to provide an important baseline to assess the future prophylactic and therapeutic options.Öğe A Single Clone Acinetobacter baumannii Outbreak in a State Hospital in Turkey(Natl Inst Infectious Diseases, 2013) Cicek, Aysegul Copur; Karagoz, Alper; Koksal, Ersin; Erturk, Ayse; Ozgumus, Osman Birol; Koksal, Zeynep Senturk; Durmaz, RizaAcinetobacter baumannii is an important pathogen in hospitalized patients, particularly those in the intensive care unit (ICU). A total of 21 A. baumannii (6 from 5 patients and 15 from environmental samples) were isolated in the ICU and the isolation room of a state hospital in June 2011. The possible source of the outbreak was investigated. A. baumannii isolates were identified using conventional biochemical tests, BBL Crystal Identification Systems, OXA-51 specific PCR, and 16S rDNA sequencing. All the isolates were multidrug-resistant, showing resistance to cephalosporins, carbapenems, fluoroquinolones, and the aminoglycoside group of antibiotics. Pulsed-field gel electrophoresis suggested that all A. baumannii isolates were derived from a common source.
