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6. Antibiotic resistance in Campylobacter jejuniand Campylobacter coli:significant contribution of an RND type efflux pump in erythromycin resistance

Author

Oncel, Beyza, Hasdemir, Ufuk, Aksu, Burak, and Pournaras, Spyros

Abstract

AbstractIn this study, we aimed to determine the antibiotic resistance status of Campylobacterspp. isolated from human infections in our region, including the role of mechanisms involved in erythromycin resistance. Standard methods were used for the isolation, identification and antibiotic susceptibility testing of Campylobacterspp. isolates. Erythromycin-resistant mutants were selected from erythromycin-susceptible clinical isolates, and the erythromycin resistance mechanisms were investigated phenotypically by determining the erythromycin MICs of isolates in the presence and absence of the resistance nodulation cell division (RND) type efflux pump inhibitor, phenylalanine-arginine β-naphthylamide dihydrochloride (PAβN), and genotypically by determining ribosomal and cmeABCalterations using PCR and DNA sequence analysis. Campylobacterspp., including 184 C. jejuniand 20 C. coliin a two-year period, were the most frequently isolated gastrointestinal bacterial pathogens in our region. However, in both C. jejuniand C. coli,resistance to tetracycline and ciprofloxacin were found to be high, erythromycin resistance was especially high (20%) in C. coli. With a ribosomal alteration, A2075G, which was found to be associated with high-level erythromycin resistance in clinical isolates, PAβN significantly reduced the erythromycin MICs in both clinical isolates and mutants. An important finding of this study, while considering cmeABCoperon, is the explanation of why erythromycin resistance is more common among C. colithan C. jejuni,bearing in mind the specific deletions and alterations in the intergenic region of the operon in all erythromycin-resistant C. coliisolates. Ultimately, these findings revealed the significant role of RND-type efflux activity in increased erythromycin MICs of the isolates.

Published
2024
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7. One-Year Post-Vaccination Longitudinal Follow-Up of Quantitative SARS-CoV-2 Anti-Spike Total Antibodies in Health Care Professionals and Evaluation of Correlation with Surrogate Neutralization Test

Author

Tuyji Tok, Yesim, primary, Can Sarinoglu, Rabia, additional, Ordekci, Seyhan, additional, Yilmaz, Serife, additional, Ozcolpan, Gunes, additional, Bayram, Aysen, additional, Nohut, Okan Kadir, additional, Kocer, Ipek, additional, Hasdemir, Ufuk, additional, Kuskucu, Mert Ahmet, additional, Konukoglu, Dildar, additional, Gozalan, Aysegul, additional, Midilli, Kenan, additional, and Celik, Gulden, additional

Published
2023
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9. Investigation of IBC-1, a Rare Plasmid-Mediated Class A Beta-lactamase in Members of Enterobacterales

Author

ALTINKANAT GELMEZ, Gülşen, HASDEMİR, Ufuk, and SÖYLETİR, Güner

Subjects
GSBL,IBC-1,E. coli,K. pneumoniae,E. cloacae, Medicine, ESBL,IBC-1,E. coli,K. pneumoniae,E. cloacae, Tıp
Abstract

Amaç: Bu çalışmanın amacı, tüm dünyada sıklıkla gözlemlenen geniş spektrumlu beta laktamazları (GSBL) TEM, SHV ve CTX-M ve nadir görülen IBC-1 beta laktamaz enziminin varlığını araştırmaktır.Gereç ve Yöntem: Marmara Üniversitesi Hastanesinde yatan has-taların klinik örneklerinden izole edilen, fenotipik olarak GSBL üre-ten ve IBC-1 fenotipi gösteren 30 köken çalışmaya dahil edilmiştir. Antibiyotik duyarlılık testleri disk difüzyon ve agarda dilüsyon yön-temi ile gerçekleştirilmiştir. GSBL enzimlerinin fenotipik olarak sap-tanmasında E-test ve çift disk sinerji yöntemi kullanılmıştır. GSBL üretiminden sorumlu olan genlerinin varlığını saptamak amacıyla polimeraz zincir reaksiyonu (PZR) yapılmıştır.Bulgular: Kökenlerin tamamı, imipeneme duyarlı bulunurken, am-pisilin, amoksisilin klavulanik asit, piperasilin, seftazidim ve trime-toprim sülfametaksazole dirençli olarak; saptanmıştır. E-test yön-temiyle 4 köken tanımsız, 26 köken ise GSBL pozitif saptanmıştır. Çift disk sinerji yöntemi ile 2 köken fenotipik olarak IBC-1 pozitif iken, 5 köken şüpheli pozitif olarak belirlenmiştir. Kökenlerimizin blaTEM, blaSHV ve blaCTX-M genlerini taşıma oranı sırasıyla %73,3, %60 ve %56,6 olarak belirlenmiştir. blaIBC geni ise hiçbir kökende sap-tanmamıştır.Sonuç: İlk olarak Yunanistan’da saptanan IBC-1 enzimi ülkemiz için henüz bir tehlike oluşturmazken GSBL pozitif kökenlerde TEM, SHV ve CTX-M enzimlerinin oranı oldukça yüksek olarak tespit edilmiş-tir., Objective: The aim of the study was to investigate the presence of extended -spectrum beta-lactamases (ESBL) TEM, SHV, and CTX-M which are frequently observed all over the world, and the rare IBC-1 betalactamase enzyme. Material and Method: Thirty strains that isolated from various clinical samples from inpatient at Marmara University Hospital, which were phenotypically positive for ESBL, and IBC-1were included in the study. Antimicrobial susceptibility tests were per-formed both by disk diffusion and agar dilution tests. E-test and double-disc synergy method (DDS) were used for phenotypic detection of ESBLs. The presence of ESBL genes was detected by polymerase chain reaction (PCR).Results: All strains were susceptible to imipenem while ampicil-lin, amoxicillin-clavulanic acid, piperacillin, ceftazidime, and trimethoprim-sulfamethoxazole were resistant. While 4 strains were unidentified, 26 strains were detected as ESBL positive by E-test. Two strains were phenotypically positive for IBC-1 with DDS, while 5 strains were identified as doubtful. The rate of carrying the blaTEM, blaSHV, and blaCTX-M genes of strains was 73.3%, 60%, and 56.6%, respectively. The blaIBC gene was not detected in any of the strains.Conclusion: While the IBC-1 enzyme, which was first detected in Greece, have not caused a threat to our country yet, the rate of TEM, SHV, and CTX-M enzymes were found to be quite high.

Published
2021

10. Detection of a New Resistance-Mediating Plasmid Chimera in a blaOXA-48-Positive Klebsiella pneumoniae Strain at a German University Hospital

Author

Schwanbeck, Julian, Bohne, Wolfgang, Hasdemir, Ufuk, Groß, Uwe, Pfeifer, Yvonne, Bunk, Boyke, Riedel, Thomas, Spröer, Cathrin, Overmann, Jörg, Frickmann, Hagen, and Zautner, Andreas E.

Subjects
Klebsiella pneumoniae, lcsh:Biology (General), plasmid, carbapenem resistance, epidemiology, resistome, phylogeny, beta-lactamase, lcsh:QH301-705.5, Article
Abstract

Mobile genetic elements, such as plasmids, facilitate the spread of antibiotic resistance genes in Enterobacterales. In line with this, we investigated the plasmid-resistome of seven blaOXA-48 gene-carrying Klebsiella pneumoniae isolates, which were isolated between 2013 and 2014 at the University Medical Center in Göttingen, Germany. All isolates were subjected to complete genome sequencing including the reconstruction of entire plasmid sequences. In addition, phenotypic resistance testing was conducted. The seven isolates comprised both disease-associated isolates and colonizers isolated from five patients. They fell into two clusters of three sequence type (ST)101 and two ST11 isolates, respectively, and ST15 and ST23 singletons. The seven isolates harbored various plasmids of the incompatibility (Inc) groups IncF, IncL/M, IncN, IncR, and a novel plasmid chimera. All blaOXA-48 genes were encoded on the IncL/M plasmids. Of note, distinct phenotypical resistance patterns associated with different sets of resistance genes encoded by IncL/M and IncR plasmids were observed among isolates of the ST101 cluster in spite of high phylogenetic relatedness of the bacterial chromosomes, suggesting nosocomial transmission. This highlights the importance of plasmid uptake and plasmid recombination events for the fast generation of resistance variability after clonal transmission. In conclusion, this study contributes a piece in the puzzle of molecular epidemiology of resistance gene-carrying plasmids in K. pneumoniae in Germany.

Published
2021

16. Enterobacterales Üyelerinde Nadir Bir Plazmid Aracılı A Sınıfı Beta Laktamaz Olan IBC-1'in Araştırılması.

Author

Gelmez, Gülşen Altınkanat, Hasdemir, Ufuk, and Söyletir, Güner

Abstract

Copyright of Experimed is the property of Experimed and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2021
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17. The first results of national antimicrobial resistance surveillance system in Turkey Türkiye'de ulusal antimikrobiyal direnç surveyans sisteminin ilk sonuçlari

Author

EYİGÖR, METE, Perçin, Duygu, Aktaş, Dilber, Çöplü, Nilay, Şimşek, Hüsniye, Gür, Deniz, Gözalan, Ayşegül, Hasdemir, Ufuk, Gülay, Zeynep, BAYRAMOĞLU, GÜLÇİN, Gürler, Nezahat, and Aydemir, Şöhret

Abstract

© 2018 Refik Saydam National Public Health Agency (RSNPHA).Objective: In order to combat with antimicrobial resistance, some measures should be taken and determination of the current status is one of them. National antimicrobial resistance surveillance system (NAMRSS) was established for this purpose in Turkey. It was targeted to be useful for guidence of ampirical therapy, create antimicrobial usage policies, provide data to the guidebooks, and supply initial information to evaluate the efficasy of the measures taken. Methods: Data of resistance was collected from 55 hospital, from blood and cerebrospinal fluid isolates, which were S. aureus, E. faecalis and E. faecium, S. pneumoniae, E. coli, K. pneumoniae and P. aeruginosa. The antimicrobials and test methods were chosen in accordance with international surveillance systems. The collected data was analysed by WHONET software. Results: S. aureus (1437); meticillin resistance was 31.5%, rifampin, linezolid and vancomycin resistance were 65.3%, 2.3%, and 0.0%, respectively. E. faecalis (n=760) resistance of ampicillin was 9.7%, linezolid, vancomycin, teicoplanin were lower than 1%, high level (HL) aminoglycoside was around 30%. E. faecium (n=756) resistance of ampicillin was 88,1%, linezolid, teicoplanin were lower than 1%, vancomycin 17%, HL aminoglycoside was around 50%. S. pneumoniae (n=128) with non-meningitis breakpoints; resistance were lower than 5.2% for all antimicrobials other than erythromycin (32%), with meningitis breakpoints: resistance increased to 14,3-44,8%. E. coli (2280) and K. pneumoniae (1307), extended spectrum beta-lactamase (ESBL) was 51.6% and 54.0%, respectively. P. aeruginosa (825) resistance were changed in between 8.4% (amikacin) and 36.4% (piperacillin). Conclusion: The resistance was higher among the countries in close geographical region and increased in time, indicating the need for developing policies to combat with it. Besides, the results will also be valuable to monitor the usefulness of the measures taken. © 2018 Refik Saydam National Public Health Agency (RSNPHA).Amaç: Antimikrobiyal direnç ile mücadele için bazi önlemler alinmalidir, mevcut durumun saptanmasi da bunlardan biridir. Türkiye'de ulusal antimikrobiyal direnç surveyans sistemi bu hedefle kurulmuştur. Ampirik tedaviyi desteklemek, antimikrobiyal kullanim politikalari oluşturmak, rehber kitaplara veri sağlamak, alinmiş olan önlemlerin etkinliğini değerlendirmek için başlangiç bilgilerini sağlamak amaçlanmiştir. Yöntem: Elli beş hastaneden, kan ve beyin omurilik sivisindan izole edilen Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae ve Pseudomonas aeruginosa izolatlarinin direnç verileri toplanmiştir. Antimikrobiyaller ve test yöntemleri uluslararasi surveyans sitemleri ile uyumlu olacak şekilde seçilmiştir. Toplanan veriler WHONET programi ile analiz edilmiştir. Bulgular: S. aureus (n = 1437); metisilin direnci %31,5, rifampin, linezolid ve vankomisin direnci sirasi ile %65,3; %2,3 ve %0,0, bulunmustur. E. faecalis (n = 760) ampisilin direnci %9,7, linezolid, vankomisin, teikoplanin direnci %1'in altinda, yüksek düzey (YD) aminoglikozid %30 civarinda bulunmuştur. E. faecium (n = 756) ampisilin direnci %88,1; linezolid ve teikoplanin %1'den az, vankomisin %17, YD aminoglikozid %50 civarinda bulunmuştur. S. pneumoniae (n = 128) nonmenenjit sinir değerler için eritromisin (%32) dişinda tüm antimikrobiyaller için direnç %5,2'den düşüktür, menejit sinir değerler için direnç %14,3-44,8'a yükselmiştir. E. coli (2280) ve K. pneumoniae (1307) için genişlemiş spektrumlu beta-laktamaz (GSBL) direnci sirasi ile %51,6 ve %54,0 bulunmuştur. P. aeruginosa (825) direnci %8,4 (amikacin) ve %36,4 (piperacillin) arasinda değişmektedir. Sonuç: Direnç Türkiye'ye yakin coğrafyadaki ülkelerden yüksek bulunmuş ve zaman içinde artiş göstermiş olup bununla mücadele için politikalar geliştirmek gerektiğine isaret etmektedir. Ayrica, alinan önlemlerin yararliliğini izlemek için de sonuçlar değerli olacaktir.

Published
2018

20. Diversity of HIV-1 Subtypes and Transmitted Drug-resistance MutationsAmong Minority HIV-1 Variants in a Turkish Cohort

Author

Sarinoglu, Rabia Can, Sili, Uluhan, Hasdemir, Ufuk, Aksu, Burak, Soyletir, Guner, and Korten, Volkan

Abstract

Background: The World Health Organization (WHO) recommends the surveillance oftransmitted drug resistance mutations (TDRMs) to ensure the effectiveness and sustainability ofHIV treatment programs. Objective: Our aim was to determine the TDRMs and evaluate the distribution of HIV-1 subtypesusing and compared next-generation sequencing (NGS) and Sanger-based sequencing (SBS) in acohort of 44 antiretroviral treatment-naïve patients. Methods: All samples that were referred to the microbiology laboratory for HIV drug resistanceanalysis between December 2016 and February 2018 were included in the study. After exclusions,44 treatment-naive adult patients with a viral load of >1000 copies/mL were analyzed. DNA sequencingfor reverse transcriptase and protease regions was performed using both DeepChek ABLsingle round kit and Sanger-based ViroSeq HIV-1 Genotyping System. The mutations and HIV-1subtypes were analyzed using the Stanford HIVdb version 8.6.1 Genotypic Resistance software,and TDRMs were assessed using the WHO surveillance drug-resistance mutation database. HIV-1subtypes were confirmed by constructing a maximum-likelihood phylogenetic tree using Los AlamosIQ-Tree software. Results: NGS identified nucleos(t)ide reverse transcriptase inhibitor (NRTI)-TDRMs in 9.1 % ofthe patients, non-nucleos(t)ide reverse transcriptase inhibitor (NNRTI)-TDRMs in 6.8 % of the patients,and protease inhibitor (PI)-TDRMs in 18.2 % of the patients at a detection threshold of ≥ 1%. Using SBS, 2.3 % and 6.8 % of the patients were found to have NRTI- and NNRTI-TDRMs, respectively,but no major PI mutations were detected. M41L, L74I, K65R, M184V, and M184I relatedto NRTI, K103N to NNRTI, and N83D, M46I, I84V, V82A, L24I, L90M, I54V to the PI siteswere identified using NGS. Most mutations were found in low-abundance (frequency range: 1.0 %- 4.7 %) HIV-1 variants, except M41L and K103N. The subtypes of the isolates were found as follows;61.4 % subtype B, 18.2 % subtype B/CRF02_AG recombinant, 13.6 % subtype A, 4.5 % CRF43_02G, and 2.3 % CRF02_AG. All TDRMs, except K65R, were detected in HIV-1 subtype Bisolates. Conclusion: The high diversity of protease site TDRMs in the minority HIV-1 variants and prevalenceof CRFs were remarkable in this study. All minority HIV-1 variants were missed by conventionalsequencing. TDRM prevalence among minority variants appears to be decreasing over timeat our center.

Published
2022
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21. Kolistin Duyarlılık Testi İçin Diagnostics Colistin MIC-Strip Testinin Değerlendirilmesi.

Author

Gelmez, Gülşen Altınkanat, Sayın, Elvan, Hasdemir, Ufuk, and Söyletir, Güner

Abstract

Copyright of ANKEM Antibiyotik & Kemoterapi Dergisi is the property of ANKEM Antibiyotik & Kemoterapi Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2021
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26. The relationship between macrolide resistance mechanisms and serotypes of Streptococcus pneumoniae

Author

TİRYAKİOĞLU, Nebahat, AKSU, Burak, and ÖVER HASDEMİR, Ufuk

Subjects
biochemical phenomena, metabolism, and nutrition, Makrolid direnci,erm(B),mef(E),serotip,Streptococcus pneumoniae
Abstract

Objective: Increased resistance rate to macrolides used as empirical treatment of pneumococcal infections is a major problem in our country and all over the world. In our study, we aimed to determine macrolide resistance mechanisms of the erythromycin-resistant Streptococcus pneumonia isolated from clinical samples and to investigate serotype and resistance relationship within our region with the high macrolide resistance rates among pneumococci.Methods: Fifty isolates were studied for erythromycin, azithromycin, clarithromycin, clindamycin susceptibilities with disk diffusion, and liquid microdilution methods. Genetic determinants of macrolide resistance, mef(A), mef(E), erm(B), erm(TR) genes were investigated by PCR using specific primers for each gene, multiplex PCR was used to determine the serotypes. Results: Constitutive and inducible MLSB phenotypes and M phenotype were expressed in 86%, 4% and 10% of the isolates, respectively. Total of 42% of the isolates (n=21) were positive for erm(B), 12% (n=6) for mef(E) gene, in 46% (n=23) of the isolates both genes were detected. Serotype distribution was as follows: 28 (56%) 19F, 6 (12%) 6A/B, 5 (10%) 23F, 1 (2%) 39, 2 (4%) 15A-F, 1 (2%) 14, 1 (% 2) 23B and 6 (%12) isolates were nontypeable. 12 isolates carry erm(B), and 16 isolates carry both erm(B) and mef(E) in serotype 19F. One isolate carries erm(B), and 5 isolates carry both erm(B) and mef(E) in serotype 6A/B. Four isolates carry erm(B) and one isolate carries both erm(B) and mef(E) in serotype 23F.Conclusion: The most striking results of this study are the presence of macrolide efflux pump coding mef(E) gene in 58% of our isolates, the presence of additional erm(B) gene in %46 of isolates, and high rate of erm(B)+ mef(E) genes combination (56%) in predominant serotype 19F isolates.Key words: Macrolide resistance, erm(B), mef(E), serotype, Streptococcus pneumoniae, Amaç: Pnömokok enfeksiyonlarının tedavisinde ampirik olarak kullanılan makrolid grubu antibiyotiklerdeki direnç oranlarının artışı, tüm dünyada ve ülkemizde önemli bir sorundur. Çalışmamızda; pnömokoklarda makrolid direncinin yüksek olduğu bölgemizde, başvuran hastaların klinik örneklerinden izole edilen eritromisin dirençli Streptococcus pneumoniae izolatlarında makrolid direnç mekanizmalarının belirlenmesi ve direncin klinik izolatlarımızın serotipleri ile ilişkisinin incelenmesi amaçlanmıştır. Yöntemler: Toplam 50 izolatın eritromisin, azitromisin, klaritromisin, klindamisin duyarlılıkları disk difüzyon yöntemi ile; minimum inhibitor konsantrasyonları ise sıvı mikrodilüsyon yöntemi ile belirlenmiştir. Makrolid direncinin genetik determinantları mef(A), mef(E), erm(B), erm(TR) her gene özgü primerler kullanılarak PZR yöntemiyle, serotip tayini ise multipleks PZR ile araştırılmıştır.Bulgular: İzolatların %86’sı yapısal, %4’ü indüklenebilir MLSB fenotipi; %10’u M fenotipi göstermiştir. İzolatların %42’sinde (n:21) sadece erm(B), %12’sinde (n:6) sadece mef(E) geni, %46’sında da (n:23) her iki gen birlikte saptanmıştır. İzolatların serotip dağılımı; 28’i (%56) 19F, 6’sı (%12) 6A/B, 5’i (%10) 23F, 1’i (%2) 39, 2’si (%4) 15A-F, 1’i (%2) 14, 1’i (%2) 23B şeklindedir; 6 (%12) izolat ise tiplendirilememiştir. 19F serotipindeki izolatların; 12’si sadece erm(B), 16’sı erm(B) ile mef(E) genini birlikte taşımaktadır. 6A/B serotipindeki izolatların 1’i sadece erm(B), 5’i mef(E) ile beraber erm(B) geni bulundurmaktadır. 23F serotipindeki izolatların ise 4’ü sadece mef(E), 1’i mef(E) ile birlikte erm(B) geni taşımaktadır. Sonuç: Makrolid atım pompa geni mef(E)’nin kökenlerimizin %58’inde bulunması, %46’sında bu genin erm(B)’ye eşlik ettiğinin gösterilmesi ve koleksiyonumuzda baskın olarak saptanan 19F serotipindeki izolatlarda erm(B)+mef(E) gen birlikteliğinin çok yüksek oranda (%56) bulunması çalışmamızın çarpıcı sonuçlarıdır.Anahtar Kelimeler : akrolid direnci, erm(B), mef(E), serotip, Streptococcus pneumoniae

Published
2014

28. Investigation of Carbapenemases in Carbapenem-Resistant Escherichia coli and Klebsiella pneumoniae Strains Isolated in 2014 in Turkey

Author

ÇAKAR, Aslı, primary, AKYÖN, Yakut, additional, GÜR, Deniz, additional, KARATUNA, Onur, additional, ÖĞÜNÇ, Dilara, additional, ÖZHAK BAYSAN, Betil, additional, ÇÖPLÜ, Nilay, additional, ÇAĞATAY, Mustafa, additional, KILIÇ, Abdullah, additional, BAYSALLAR, Mehmet, additional, BAKICI, Zahir, additional, ÇELİK, Cem, additional, GÜLAY, Zeynep, additional, AYDEMİR, Şöhret, additional, TÜNGER, Alper, additional, KILIÇ, Hüseyin, additional, ERÇAL, Barış Derya, additional, AŞÇI TORAMAN, Zulal, additional, ZER, Yasemin, additional, BÜYÜKTAŞ, Ayşe, additional, AY, Selma, additional, AKTAŞ, Zerrin, additional, KAYACAN, Çiğdem, additional, BAYRAMOĞLU, Gülçin, additional, AYDIN, Faruk, additional, DÜNDAR, Devrim, additional, HASDEMİR, Ufuk, additional, AYAŞ, Ramazan, additional, YANIK, Keramettin, additional, GÜNAYDIN, Murat, additional, GÜDÜCÜOĞLU, Hüseyin, additional, and PARLAK, Mehmet, additional

Published
2016
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32. Streptococcus Pneumoniae'da Makrolid Direnç Mekanizmalari ile Serotip İlişkisi.

Author

TiryakioĞlu, Nebahat, Aksu, Burak, and Hasdemir, Ufuk Över

Subjects
MACROLIDE antibiotics, STREPTOCOCCUS pneumoniae, SEROTYPES, POLYMERASE chain reaction, DNA primers, ERYTHROMYCIN
Abstract

Copyright of Journal of Marmara University Institute of Health Sciences is the property of Marmara University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2012

33. Simple and reliable detection of slime production of Candidaspp. directly from blood culture bottles: Comparison of visual tube method and transmission electron microscopy

Author

Cerikcioglu, Nilgun, Hasdemir, Ufuk, San, Tangul, Salik, Emsal, and Soyletir, Guner

Abstract

Early detection of slime production may be useful for clinical decision because of its suggestive property for potential pathogenic capacity of a Candidastrain especially in patients with a prosthetic device. In this study we aimed to compare the visual tube method (VTM) with transmission electron microscopy (TEM) in order to confirm the reliability of the former method. In order to demonstrate the reproducibility of the tube method and to determine the correct timing for the test, Candidaisolates directly obtained from blood culture (DBC) bottles and their two subsequent subcultures were used. The results of this study showed that VTM is a simple and reliable method which can be used in every clinical mycology laboratory, provided that the test is applied on DBC isolates; as the ability of slime production is decreased or lost even after the first subculturing. We suggest that this simple method can be used and may have some contributions to the ongoing studies on the controversial issue concerning removal of biomaterials in candidemic patients.

Published
2004
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34. Detection and Prevalence of Active Drug Efflux Mechanism in Various Multidrug-Resistant Klebsiella pneumoniaeStrains from Turkey

Author

Hasdemir, Ufuk Over, Chevalier, Jacqueline, Nordmann, Patrice, and Page`s, Jean-Marie

Abstract

ABSTRACTThe prevalence of active drug efflux pump and porin alterations was investigated in Turkish nosocomial strains of Klebsiella pneumoniaeexhibiting a multidrug-resistant phenotype. MICs of various antibiotics, including quinolones, chloramphenicol, tetracycline, and ß-lactams, for those strains were determined either with or without the efflux pump inhibitor phenylalanine arginine ß-naphthylamide (PAßN). Thirty-nine percent of the strains exhibited a PAßN-modulated resistance for quinolones, chloramphenicol, and tetracycline. In these strains, a significant increase of chloramphenicol accumulation was gained in the presence of the efflux pump inhibitor PAßN or with the energy uncoupler carbonyl cyanide m-chlorophenylhydrazone. Moreover, high-level expression of the membrane fusion protein AcrA, which was immunodetected in most of those isolates, suggests that the AcrAB/TolC efflux machinery contributed to their antibiotic resistance. Studies of K. pneumoniaeporins indicated that the majority of the strains, including extended-spectrum ß-lactamase producers and efflux-positive ones, presented an alteration in their sorbitol-sensitive porin (OmpK35) expression. This is the first report showing the prominent role of active drug efflux in the antibiotic resistance of nosocomial K. pneumoniaestrains from Turkey.

Published
2004
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35. Detection of a New Resistance-Mediating Plasmid Chimera in a bla OXA-48 -Positive Klebsiella pneumoniae Strain at a German University Hospital.

Author

Schwanbeck, Julian, Bohne, Wolfgang, Hasdemir, Ufuk, Groß, Uwe, Pfeifer, Yvonne, Bunk, Boyke, Riedel, Thomas, Spröer, Cathrin, Overmann, Jörg, Frickmann, Hagen, and Zautner, Andreas E.

Subjects
PLASMIDS, KLEBSIELLA pneumoniae, MOBILE genetic elements, UNIVERSITY hospitals, BACTERIAL chromosomes, PHENOTYPES
Abstract

Mobile genetic elements, such as plasmids, facilitate the spread of antibiotic resistance genes in Enterobacterales. In line with this, we investigated the plasmid-resistome of seven blaOXA-48 gene-carrying Klebsiella pneumoniae isolates, which were isolated between 2013 and 2014 at the University Medical Center in Göttingen, Germany. All isolates were subjected to complete genome sequencing including the reconstruction of entire plasmid sequences. In addition, phenotypic resistance testing was conducted. The seven isolates comprised both disease-associated isolates and colonizers isolated from five patients. They fell into two clusters of three sequence type (ST)101 and two ST11 isolates, respectively; and ST15 and ST23 singletons. The seven isolates harbored various plasmids of the incompatibility (Inc) groups IncF, IncL/M, IncN, IncR, and a novel plasmid chimera. All blaOXA-48 genes were encoded on the IncL/M plasmids. Of note, distinct phenotypical resistance patterns associated with different sets of resistance genes encoded by IncL/M and IncR plasmids were observed among isolates of the ST101 cluster in spite of high phylogenetic relatedness of the bacterial chromosomes, suggesting nosocomial transmission. This highlights the importance of plasmid uptake and plasmid recombination events for the fast generation of resistance variability after clonal transmission. In conclusion, this study contributes a piece in the puzzle of molecular epidemiology of resistance gene-carrying plasmids in K. pneumoniae in Germany. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
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37. Binding site description of 2-substituted benzothiazoles as potential RND efflux pump inhibitors.

Author

Yalcin, Ismail, Yilmaz, Serap, Bolelli, Kayhan, Aki-Yalcin, Esin, and Over-Hasdemir, Ufuk

Subjects
BENZOTHIAZOLE, EFFLUX (Microbiology), DRUG resistance in bacteria
Abstract

The article focuses on a study which defines the binding site description of 2 substituted benzothiazoles as potential resistance-nodulation-cell division family (RND) efflux pump inhibitors.

Published
2016

38. Detection of a New Resistance-Mediating Plasmid Chimera in a bla(OXA-48)-Positive Klebsiella pneumoniae Strain at a German University Hospital

Author

HASDEMİR GÖKBOĞA, MÜNEVVER UFUK, Schwanbeck, Julian, Bohne, Wolfgang, Hasdemir, Ufuk, Gross, Uwe, Pfeifer, Yvonne, Bunk, Boyke, Riedel, Thomas, Sproeer, Cathrin, Overmann, Jorg, Frickmann, Hagen, and Zautner, Andreas E.

Subjects
Klebsiella pneumoniae, plasmid, carbapenem resistance, epidemiology, resistome, phylogeny, beta-lactamase
Abstract

Mobile genetic elements, such as plasmids, facilitate the spread of antibiotic resistance genes in Enterobacterales. In line with this, we investigated the plasmid-resistome of seven bla(OXA-48) gene-carrying Klebsiella pneumoniae isolates, which were isolated between 2013 and 2014 at the University Medical Center in Gottingen, Germany. All isolates were subjected to complete genome sequencing including the reconstruction of entire plasmid sequences. In addition, phenotypic resistance testing was conducted. The seven isolates comprised both disease-associated isolates and colonizers isolated from five patients. They fell into two clusters of three sequence type (ST)101 and two ST11 isolates, respectively; and ST15 and ST23 singletons. The seven isolates harbored various plasmids of the incompatibility (Inc) groups IncF, IncL/M, IncN, IncR, and a novel plasmid chimera. All bla(OXA-48) genes were encoded on the IncL/M plasmids. Of note, distinct phenotypical resistance patterns associated with different sets of resistance genes encoded by IncL/M and IncR plasmids were observed among isolates of the ST101 cluster in spite of high phylogenetic relatedness of the bacterial chromosomes, suggesting nosocomial transmission. This highlights the importance of plasmid uptake and plasmid recombination events for the fast generation of resistance variability after clonal transmission. In conclusion, this study contributes a piece in the puzzle of molecular epidemiology of resistance gene-carrying plasmids in K. pneumoniae in Germany.

Published
2021

39. [Investigation of carbapenemases in carbapenem-resistant Escherichia coli and Klebsiella pneumoniae strains isolated in 2014 in Turkey]

Author

Abdullah Kilic, Cigdem Bal Kayacan, Dilara Ogunc, Mehmet Baysallar, Devrim Dündar, Zahir Bakıcı, Aslı Çakar, Zulal Asci Toraman, Hüseyin Güdücüoğlu, Yakut Akyön, Selma Ay, Mustafa Çağatay, Faruk Aydin, Ramazan Ayaş, Cem Çelik, Ayse Buyuktas, Keramettin Yanik, Hüseyin Kiliç, Betil Özhak Baysan, Nilay Çöplü, Gülçin Bayramoğlu, Barış Derya Erçal, Mehmet Parlak, Yasemin Zer, Ufuk Hasdemir, Onur Karatuna, Alper Tünger, Murat Günaydin, Zerrin Aktaş, Deniz Gür, Zeynep Gülay, Şöhret Aydemir, [Cakar, Asli -- Akyon, Yakut -- Gur, Deniz] Hacettepe Univ, Fac Med, Dept Med Microbiol, TR-06100 Ankara, Turkey -- [Karatuna, Onur] Acibadem Univ, Fac Med, Dept Med Microbiol, Istanbul, Turkey -- [Ogunc, Dilara -- Baysan, Betil Ozhak] Akdeniz Univ, Fac Med, Dept Med Microbiol, TR-07058 Antalya, Turkey -- [Coplu, Nilay -- Cagatay, Mustafa] Ankara Diskapi Yildirim Beyazit Training & Res Ho, Microbiol Lab, Ankara, Turkey -- [Kilic, Abdullah -- Baysallar, Mehmet] Gulhane Mil Med Acad, Dept Med Microbiol, Ankara, Turkey -- [Bakici, Zahir -- Celik, Cem] Cumhuriyet Univ, Fac Med, Dept Med Microbiol, Sivas, Turkey -- [Gulay, Zeynep] Dokuz Eylul Univ, Fac Med, Dept Med Microbiol, Izmir, Turkey -- [Aydemir, Sohret -- Tunger, Alper] Ege Univ, Fac Med, Dept Med Microbiol, Izmir, Turkey -- [Kilic, Huseyin] Erciyes Univ, Fac Med, Dept Med Microbiol, Kayseri, Turkey -- [Toraman, Zulal Asci] Firat Univ, Fac Med, Dept Med Microbiol, TR-23169 Elazig, Turkey -- [Zer, Yasemin -- Buyuktas, Ayse] Gaziantep Univ, Fac Med, Dept Med Microbiol, Gaziantep, Turkey -- [Ay, Selma] Inonu Univ, Fac Med, Dept Med Microbiol, Malatya, Turkey -- [Aktas, Zerrin -- Kayacan, Cigdem] Istanbul Univ, Istanbul Fac Med, Dept Med Microbiol, Istanbul, Turkey -- [Bayramoglu, Gulcin -- Aydin, Faruk] Karadeniz Tech Univ, Fac Med, Dept Med Microbiol, Trabzon, Turkey -- [Dundar, Devrim] Kocaeli Univ, Fac Med, Dept Med Microbiol, Kocaeli, Turkey -- [Hasdemir, Ufuk -- Ayas, Ramazan] Marmara Univ, Fac Med, Dept Med Microbiol, Istanbul, Turkey -- [Yanik, Keramettin -- Gunaydin, Murat] Ondokuz Mayis Univ, Fac Med, Dept Med Microbiol, Samsun, Turkey -- [Guducuoglu, Huseyin -- Parlak, Mehmet] Yuzuncu Yil Univ, Fac Med, Dept Med Microbiol, Van, Turkey, AKYON YILMAZ, YAKUT -- 0000-0002-0919-5508, Ogunc, Dilara -- 0000-0001-6669-6811, Ege Üniversitesi, and Ondokuz Mayıs Üniversitesi

Subjects
Ertapenem, 0301 basic medicine, Microbiology (medical), Imipenem, Turkey, Klebsiella pneumoniae, 030106 microbiology, Microbial Sensitivity Tests, Drug resistance, Biology, beta-Lactams, Meropenem, beta-Lactamases, Microbiology, Carbapenemase, 03 medical and health sciences, chemistry.chemical_compound, Bacterial Proteins, Enterobacteriaceae, Drug Resistance, Multiple, Bacterial, Multiplex polymerase chain reaction, Escherichia coli, metallo-beta-lactamase, polycyclic compounds, medicine, Humans, OXA-48, General Immunology and Microbiology, Escherichia coli Proteins, biochemical phenomena, metabolism, and nutrition, bacterial infections and mycoses, biology.organism_classification, Anti-Bacterial Agents, Multiple drug resistance, Phenotype, Infectious Diseases, Carbapenems, chemistry, Thienamycins, Multiplex Polymerase Chain Reaction, medicine.drug
Abstract

WOS: 000371499500003, PubMed ID: 27058326, Carbapenems are the choice of treatment in infections caused by multidrug resistant Enterobacteriaceae. In recent years carbapenem-resistant Enterobacteriaceae isolates due to carbapenemases have been increasingly reported worldwide. Multicenter studies on carbapenemases are scarce in Turkey. The aim of this study was to determine the distribution of carbapenemases from different parts of Turkey as a part of the European Survey of Carbapenemase Producing Enterobacteriaceae (EuSCAPE) project. Beginning in November 2013, carbapenem-resistant isolates resistant to at least one of the agents, namely imipenem, meropenem, and ertapenem were sent to the coordinating center. Minimum inhibitory concentrations for these carbapenems were determined by microdilution tests following EUCAST guidelines. Production of carbapenemase was confirmed by combination disk synergy tests. Types of carbapenemases were investigated using specific primers for VIM, IMP; NDM, KPC and OXA-48 genes by multiplex polymerase chain reaction. In a six month period, 155 suspected carbapenemase-positive isolates were sent to the coordinating center of which 21 (13.5%) were E.coli and 134 (86.5%) were K.pneumoniae. Nineteen (90.5%) strains among E.coli and 124 (92.5%) strains among K.pneumoniae were shown to harbour at least one carbapenemase gene by molecular tests, with a total of 92.3% (143/155). Carbapenemases were determined as a single enzyme in 136 strains (OXA-48: 84.6%; NDM: 6.3%; VIM: 2.8%; IMP: 1.4%) and as a combination in seven isolates (OXA-48 + NDM: 2.1%; OXA-48 + VIM: 2.1%; VIM + NDM: 0.7%). KPC was not detected in any of the isolates. According to the microdilution test results, resistance to imipenem, meropenem and ertapenem in OXA-48 isolates were 59.5%, 52.9% and 100%, respectively. The combination disk synergy test was 100% compatible with the molecular test results. As most of the OXA-48 producing isolates were susceptible to meropenem but all were resistant to ertapenem, ertapenem seems to be the most sensitive agent in screening carbapenemases in areas where OXA-48 is prevalent and phenotypic combination tests can be useful in centers where molecular tests are not available.

Published
2015

40. Rutin laboratuvarımızda izole edilen klesiella pneumoniae, escherichia coli ve enterobacter cloacae kökenlerinde, yeni geniş spektrumlu beta laktamaz ibc-1’in fenotipik ve genotipik yöntemlerle saptanması

Author

Altınkanat, Gülşen, Hasdemir, Ufuk, Söyletir, Güner, and Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dalı

Subjects
Mikrobiyoloji, polycyclic compounds, Klinik Mikrobiyoloji, biochemical phenomena, metabolism, and nutrition, bacterial infections and mycoses
Abstract

ÖZET: Gram negatif çomaklarda beta laktam antibiyotiklere karşı gelişen dirençten sıklıkla sorumlu tutulan genişlemiş spektrumlu beta laktamazlar (GSBL) tüm sefalosporinleri ve monobaktamları hidroliz edebilen enzimlerdir. Bu çalışmanın amacı, çoklu antibiyotik direncinden sorumlu tutulan, TEM, SHV ve CTX-M enzimlerinin yanı sıra, yeni bir genişlemiş spektrumlu beta laktamaz olan IBC-1’in varlığını saptamaktır. Marmara Üniversitesi Hastanesi’nin değişik kliniklerinden Ocak 2004- Aralık 2005 tarihleri arasında, fenotipik olarak GSBL(+) olup, IBC-1 fenotipi gösteren (seftazidime ve beta laktam inhibitörlerine dirençli, sefotaksim, sefepim, aztreonama azalmış duyarlılık ve imipeneme duyarlı) 30 köken(12 K.pneumoniae, 11 E. coli ve 7 E. cloacae) bu çalışmaya alınmıştır. Antibiyotik duyarlılık deneyleri CLSI’nin önerilerine göre disk difüzyon ve agar dilüsyon yöntemleriyle gerçekleştirilen kökenlerin tamamı, disk difüzyon yöntemiyle ampisilin, amoksisilin klavulanik asit, piperasilin, seftazidim ve trimetoprim sülfametaksazole dirençli; imipeneme ise duyarlı bulunmuştur. Disk difüzyon yöntemiyle uyumlu olarak, kökenlerin tamamı agar dilüsyon yöntemiyle de ampisilin, piperasilin ve seftazidime dirençli; imipeneme ise duyarlı bulunmuştur. Kökenlerin 26’sı E-test ile GSBL pozitif bulunurken 4’ü tanımlanamamıştır. IBC-1 enziminin varlığını araştırmak amacıyla çift disk sinerji yönteminde imipenemden seftazidime doğru inhibisyon zonunun genişlemesi pozitif olarak değerlendirilmiştir. İki kökenimiz kesin pozitif iken 5 köken şüpheli pozitif olarak değerlendirilmiştir. Çalışmamızda kullanılan kökenlerde, GSBL üretiminden sorumlu olan bla IBC, bla TEM, bla SHV ve bla CTX-M genlerinin varlığını saptamak amacıyla polimeraz zincir reaksiyonu yapılmıştır. Kökenlerimizin 22(%73.3) tanesinde bla TEM, 18 (%60) tanesinde bla SHV, 17 (%56.6) tanesinde bla CTX-M genlerini taşıdıkları saptanmış ancak hiçbirinde bla IBC geni saptanamamıştır. Sonuçta hastanemizde izole edilen kökenlerimizde TEM, SHV ve CTX-M enzimleri yaygın bulunurken IBC-1 enzimine rastlanmamıştır. SUMMARY: Extended spectrum beta lactamases (ESBL), which are usually responsible for resistance to beta lactam antibiotics in Gram negative bacilli, are enzymes that can hydrolise cephalosporins and monobactams. The aim of this study was to detect the novel extended spectrum beta lactamase IBC-1 in addition to TEM, SHV and CTX-M type ESBLs. In this study, a total of 30 strains (12 K. pneumoniae, 11 E.coli and 7 E. cloacae) isolated from different departmants of Marmara University Hospital between January 2004- December 2005 and which produce ESBL and display IBC-1 phenotype (resistance to ceftazidime and beta lactamase inhibitors with reduced susceptibility to cefotaxime, cefepime and aztreonam and susceptibility to imipenem). Antimicrobial susceptibility tests were performed both by disk diffusion and agar dilution tests according to CLSI guidelines. All isolates were resistant to ampicillin, amoxicillin clavulanic acid, piperacillin, ceftazidime and trimethoprim sulfamethoxazole but susceptible to imipenem by both methods. ESBL phenotype was observed in 26 of the isolates but 4 isolates were found to be indeterminate by E-test ESBL strips. Enhanced inhibition zone between imipenem and ceftazidime in double disk synergy test has been evaluated as positive for the presence of IBC-1. Two isolates were clearly positive while the results were doubtfull in five isolates for IBC-1. A polimerase chain reaction was performed for bla IBC, bla TEM, bla SHV and bla CTX-M genes. Among the 30 isolates, the rates for TEM, SHV, CTX-M beta lactamases were found %73.3, %60, %56.6 respectively while none of the isolates carried IBC-1 gene.. In conclusion, the results of our study indicated that common ESBLs including TEM, SHV and CTX-M were widely but not IBC-1 in our hospital.

Published
2006

41. Rutin laboratuvarımızda izole edilen E.coli, K. pneumoniae ve E. cloacae kökenlerinde yeni bir geniş spektrumlu beta laktamaz IBC-1'in fenotipik ve genotipik yöntemlerle saptanması

Author

Altinkanat, Gülşen, Hasdemir, Ufuk, Söyletir, Güner, and Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dalı

Subjects
Mikrobiyoloji, Microbiology
Abstract

ÖZETGram negatif çomaklarda beta laktam antibiyotiklere karşı gelişendirençten sıklıkla sorumlu tutulan genişlemiş spektrumlu beta laktamazlar (GSBL) tümsefalosporinleri ve monobaktamları hidroliz edebilen enzimlerdir. Bu çalışmanın amacı,çoklu antibiyotik direncinden sorumlu tutulan, TEM, SHV ve CTX-M enzimlerinin yanısıra, yeni bir genişlemiş spektrumlu beta laktamaz olan IBC-1'in varlığını saptamaktır.Marmara Üniversitesi Hastanesi'nin değişik kliniklerinden Ocak 2004- Aralık 2005tarihleri arasında, fenotipik olarak GSBL(+) olup, IBC-1 fenotipi gösteren (seftazidimeve beta laktam inhibitörlerine dirençli, sefotaksim, sefepim, aztreonama azalmışduyarlılık ve imipeneme duyarlı) 30 köken(12 K.pneumoniae, 11 E. coli ve 7 E.cloacae) bu çalışmaya alınmıştır. Antibiyotik duyarlılık deneyleri CLSI'nin önerilerinegöre disk difüzyon ve agar dilüsyon yöntemleriyle gerçekleştirilen kökenlerin tamamı,disk difüzyon yöntemiyle ampisilin, amoksisilin klavulanik asit, piperasilin, seftazidimve trimetoprim sülfametaksazole dirençli; imipeneme ise duyarlı bulunmuştur. Diskdifüzyon yöntemiyle uyumlu olarak, kökenlerin tamamı agar dilüsyon yöntemiyle deampisilin, piperasilin ve seftazidime dirençli; imipeneme ise duyarlı bulunmuştur.Kökenlerin 26'sı E-test ile GSBL pozitif bulunurken 4'ü tanımlanamamıştır. IBC-1enziminin varlığını araştırmak amacıyla çift disk sinerji yönteminde imipenemdenseftazidime doğru inhibisyon zonunun genişlemesi pozitif olarak değerlendirilmiştir. kikökenimiz kesin pozitif iken 5 köken şüpheli pozitif olarak değerlendirilmiştir.Çalışmamızda kullanılan kökenlerde, GSBL üretiminden sorumlu olan bla IBC, bla TEM,bla SHV ve bla CTX-M genlerinin varlığını saptamak amacıyla polimeraz zincir reaksiyonuyapılmıştır. Kökenlerimizin 22(%73.3) tanesinde bla 18 (%60) tanesinde bla SHV,TEM,17 (%56.6) tanesinde bla genlerini taşıdıkları saptanmış ancak hiçbirinde blaCTX-M IBCgeni saptanamamıştır. Sonuçta hastanemizde izole edilen kökenlerimizde TEM, SHV veCTX-M enzimleri yaygın bulunurken IBC-1 enzimine rastlanmamıştır.Anahtar kelimeler: E.coli, K.pneumoniae, E. cloacae, Genişlemiş Spektrumlu BetaLaktamaz, IBC-1.1 SUMMARYExtended spectrum beta lactamases (ESBL), which are usually responsiblefor resistance to beta lactam antibiotics in Gram negative bacilli, are enzymes that canhydrolise cephalosporins and monobactams. The aim of this study was to detect thenovel extended spectrum beta lactamase IBC-1 in addition to TEM, SHV and CTX-Mtype ESBLs. In this study, a total of 30 strains (12 K. pneumoniae, 11 E.coli and 7 E.cloacae) isolated from different departmants of Marmara University Hospital betweenJanuary 2004- December 2005 and which produce ESBL and display IBC-1 phenotype(resistance to ceftazidime and beta lactamase inhibitors with reduced susceptibility tocefotaxime, cefepime and aztreonam and susceptibility to imipenem). Antimicrobialsusceptibility tests were performed both by disk diffusion and agar dilution testsaccording to CLSI guidelines. All isolates were resistant to ampicillin, amoxicillinclavulanic acid, piperacillin, ceftazidime and trimethoprim sulfamethoxazole butsusceptible to imipenem by both methods. ESBL phenotype was observed in 26 of theisolates but 4 isolates were found to be indeterminate by E-test ESBL strips. Enhancedinhibition zone between imipenem and ceftazidime in double disk synergy test has beenevaluated as positive for the presence of IBC-1. Two isolates were clearly positivewhile the results were doubtfull in five isolates for IBC-1. A polimerase chain reactionwas performed for bla IBC, bla TEM, bla SHV and bla CTX-M genes. Among the 30 isolates,the rates for TEM, SHV, CTX-M beta lactamases were found %73.3, %60, %56.6respectively while none of the isolates carried IBC-1 gene.. In conclusion, the results ofour study indicated that common ESBLs including TEM, SHV and CTX-M werewidely but not IBC-1 in our hospital.Key words: E.coli, K.pneumoniae, E. cloacae, Extended Spectrum Beta Lactamases,IBC-1.1 64

Published
2006

42. Sultancifliği semtinde yaşayan asemptomatik çocuklarda enterik patojenlerin bulunma sıklığı

Author

Karavelioğlu, Salim, Hasdemir, Münevver Ufuk, Mikrobiyoloji Anabilim Dalı, and Hasdemir, Ufuk

Subjects
Mikrobiyoloji, Microbiology
Abstract

ÖZET Bu çalışma, Temmuz-Ağustos 2001 tarihleri arasında, İstanbul'un Sultançıfliği yerleşim bölgesinde yaşayan, şikayeti olmayan, 4-12 yaş arasındaki 1069 çocukta barsak patojenlerinin prevalansının saptanması amacıyla yapıldı. Alınan dışkı örneklerinde parazitik inceleme için etil-asetat sedimentasyon yöntemi, ayrıca Enterobius vermicularis için selofan bant yöntemi kullanıldı. Bakteriye! ajanlardan sadece Salmonella ve Shigella türleri araştırıldı; izolasyon ve tanımlama klasik bakteriyolojik yöntemler kullanılarak yapıldı. Araştırılan patojenler 522 (%48.8) çocukta saptandı. En sık saptanan patojenlerin oranları Enterobius vermicularis, Blastocystis hominis, Giardia lamblia için sırasıyla %24; %23.6; %11.8 olarak belirlendi. Diğer parazitik patojenler sadece 6 (%0.6) çocukta saptandı. Salmonella ve Shigella türlerinin izolasyon oranı %0.6 olarak belirlendi. Enterik patojenlerin bulunma sıklığına etkili olabileceği düşünülen faktörlerden cinsiyet, yaş, babanın eğitim düzeyi, ailenin aylık geliri, aynı evde yaşayan çocuk sayısı, daha önce parazit tedavisi almak istatistiksel olarak anlamsız bulunurken, annenin eğitim düzeyinin düşük olması (P=0.002) ve içme suyu kaynağı olarak kuyu suyu kullanılması (P=0.004) enterik patojen bulunma sıklığını artıran faktörler olarak belirlendi. Sonuç olarak; büyük kentlerin, `Sultançiftliği` gibi, altyapı eksikliklerinin, eğitim, sosyal ve ekonomik sorunların yaşandığı yerleşim bölgelerinde özellikle paraziter olmak üzere enterik patojenlerin oldukça yüksek oranlarda saptanması dikkat çekicidir. Bu durum, salgın infeksiyöz hastalıklar gibi ciddi sağlık problemleri açısından bir tehdit oluşturabilir. Anahtar sözcükler: Çocuklar, dışkı örnekleri, enterik patojenler, prevalans. ıı İNGİLİZCE ÖZET (ABSTRACT) This study was performed to investigate the prevalence of enteric pathogens in asymptomatic children aged 4-12 years living in Sultançifliği, a slum area of Istanbul, during June-August 2001. Ethyl-acetate sedimentation method was used for parasitic examination of stool samples whereas Enterobius vermicularis was investigated by using cell-tape technique. Salmonella and Shigella species were the only bacterial agents investigated and isolation and identification were performed by conventional methods. Those pathogens were detected in 522 (48.8%) of children. The parasites most commonly found were Enterobius vermicularis (24%), Blastocystis hominis (23.6%) and Giardia lamblia (11.8%), other parasitic pathogens were found only in 6 (0.6%) of children. The isolation rate of Salmonella and Shigella was 0.6%. Among questioned risk factors sex, age, father's educational degree, monthly income, number of children living at the same home, having previous antiparasitic therapy were not statistically significant. Mother's educational degree and usage of well-water as water source were the only significant factors (P=0.002 and 0.004 respectively). High prevalance of enteric pathogens, especially parasites in slum areas, like Sultanciftligi, of big cities where people are having sanitary, educational and economical problems is a remarkable result of this study. This situation seems likely to be a threat for possible epidemics of infectious diseases. Key words: Children, stool samples, enteric pathogens, prevalance. m 54

Published
2003

43. [Serotype distribution and antibiotic susceptibilities of Streptococcus pneumoniae causing acute exacerbations and pneumonia in children with chronic respiratory diseases].

Author

Altınkanat Gelmez G, Soysal A, Kuzdan C, Karadağ B, Hasdemir U, Bakır M, and Söyletir G

Subjects
Acute Disease, Adolescent, Child, Child, Preschool, Chronic Disease, Disk Diffusion Antimicrobial Tests, Drug Resistance, Bacterial genetics, Genotype, Humans, Infant, Macrolides pharmacology, Multiplex Polymerase Chain Reaction, Phenotype, Pneumococcal Infections prevention & control, Pneumococcal Vaccines, Pneumonia, Pneumococcal microbiology, Pneumonia, Pneumococcal prevention & control, Respiratory Tract Diseases complications, Serotyping, Streptococcus pneumoniae genetics, Turkey, Vaccination statistics & numerical data, Young Adult, Anti-Bacterial Agents pharmacology, Pneumococcal Infections microbiology, Respiratory Tract Diseases microbiology, Streptococcus pneumoniae classification, Streptococcus pneumoniae drug effects
Abstract

This study aimed to investigate serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolates obtained from children with chronic respiratory diseases admitted to hospital with a diagnosis of acute exacerbations between 2008-2010 at Marmara University Hospital, Istanbul, Turkey. Sixty one S.pneumoniae strains isolated from the respiratory samples of patients were studied for erythromycin, clindamycin, tetracyline, trimethoprim-sulphametoxazole (TMP-SMX), vancomycin, levofloxacin susceptibilities by disk diffusion method; MIC values of penicillin and ceftriaxone were determined by E-test (AB Biodisk, Sweden). Results were evaluated according to the CLSI standards. The erythromycin-clindamycin double disc method was applied for the detection of macrolide resistance phenotypes. The presence of macrolide resistance genes, ermB, mef(A)/(E), ermTR were determined by PCR using specific primers for each gene. The serotypes were determined by multiplex PCR using specific primers for 40 different serotypes. According to CLSI criteria, penicillin resistance in S.pneumoniae isolates were found to be 8.2% (5/61) and intermediate resistance rate was 54% (33/61) for oral penicillin. Penicillin resistance were found to be only 1.6% (1/61) for parenteral penicillin. Resistance rates of erythromycin, clindamycin, tetracyline, TMP-SMX were detected as 55.8%, 46%, 47.5% and 67.2%; respectively. No resistance was detected to vancomycin and levofloxacin. Constitutive macrolide-lincosamide-streptogramin B (cMLSB) phenotype and M phenotype were observed in 82.4% (n= 28) and 17.6% (n= 6) of the macrolide resistant isolates, respectively. Inducible macrolide-lincosamide-streptogramin B (iMLSB) phenotype was not detected. The macrolid resistance genotypes, ermB, mef(A)/(E), were positive 50% and 14.7%; respectively. Both ermB and mef(A)/(E) genes were detected 35.3% of the macrolid resistant isolates. None of the isolates were positive for ermTR gene. The most common S.pneumoniae serotypes were determined as serotype 19F, 23F and 6, furthermore penicillin (34%, 15.7% and 18.4%, respectively) and macrolide (38.2%, 20.6% and 14.7%, respectively) resistance rates of those serotypes were found relatively high. Serotype covarage of 7-, 10-, 13-valent conjugated pneumococcal vaccines and 23-valent pneumococcal vaccine were 65%, 67%, 69%, and 78.6%, respectively. In our country, use of the vaccines with these coverage rates has been observed to be effective in children exposed to intensive use of antibiotics with chronic lung disease.

Published
2013
Full Text
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44. [The role of cell wall organization and active efflux pump systems in multidrug resistance of bacteria].

Author

Hasdemir U

Subjects
Biological Transport, Active physiology, Cell Wall physiology, Gram-Negative Bacteria physiology, Gram-Negative Bacteria ultrastructure, Gram-Positive Bacteria physiology, Gram-Positive Bacteria ultrastructure, Humans, Membrane Transport Proteins drug effects, Membrane Transport Proteins genetics, Bacterial Proteins physiology, Drug Resistance, Multiple, Bacterial physiology, Gram-Negative Bacteria drug effects, Gram-Positive Bacteria drug effects, Membrane Transport Proteins physiology
Abstract

Multiple antibiotic resistance of clinically important bacteria are of major concern worldwide. Alterations of drug targets or enzymatic inactivation of antimicrobial agents are the well known mechanisms of antimicrobial drug resistance. Besides these well known mechanisms, recent studies have shown that a further resistance mechanism, active drug efflux, has become increasingly important in the current threat of multidrug resistance. It involves certain bacterial transport proteins which pump out toxic antimicrobial compounds from the cell. Drug efflux pump proteins in bacteria fall into five distinct protein super families [ATP binding cassette super family (ABC), Major facilitator super family (MFS), Small multidrug resistance super family (SMR), Multidrug and toxic compound extrusion (MATE) super family, Resistance-nodulation-cell division (RND) super family] and are mostly encoded by chromosomal genes. Among them, the members of RND protein super family are widely distrubuted in Gram negative bacteria and play siginificant role in both, intrinsic and acquired multidrug resistance of these bacteria with very wide substrate specificity. RND type multidrug efflux proteins usually function together with an outer membrane canal protein (OMP) and a membrane fusion protein (MFP) to pump out drugs. AcrAB-TolC of Escherichia coli and MexAB-OprM of Pseudomonas aeruginosa are the typical examples of these tripartite systems. They are constitutively expressed in wild type cells and play significant role in intrinsic resistance of these bacteria. However, multidrug resistance which is of major clinical significance, rises as a result of overexpression of these pump systems due to mutations and elevated levels of resistance are recorded to structurally unrelated antimicrobial drugs such as fluoroquinolones, beta-lactams, tetracyclines, chloramphenicol, trimethoprim, aminoglycosides and toxic compunds. Synthesis of RND type pump proteins are regulated by complex genetic mechanisms and global activator proteins (MarA, SoxS, Rob) are significant in the induction of overexpression of these efflux pump systems. Outer membrane of Gram negative bacteria with its unique lipopolysaccharide rich structure also contributes to drug efflux and other antimicrobial resistance mechanisms by reducing the influx rate of toxic antimicrobial compunds. Multidrug efflux pump proteins found in Gram positive bacteria and mycobacteria are usually the members of protein super families other than RND family and their substrate profiles are more limited. However, some of these efflux proteins (NorA, MsrA, QacA in Staphylococcus aureus; PmrA and EmeA in Streptococcus pneumoniae) have clinical significance in the resistance to several antimicrobial agents (fluoroquinolones, macrolids) and toxic substances (quarternery ammonium compounds). In this review article, the role of cell wall organization and active efflux pump systems in multidrug resistance of bacteria have been discussed.

Published
2007

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