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The Pseudomonas quinolone signal (PQS) is an important quorum-sensing molecule for Pseudomonas aeruginosa that regulates virulence factors, chelates iron, and is an important factor in interactions with eukaryotes, including fungi and mammalian hosts. It was previously shown to inhibit or boost Aspergillus, depending on the milieu iron concentration. We studied several molecular modifications of the PQS molecule, and their effects on Aspergillus biofilm metabolism and growth in vitro, and the effects of iron supplementation. We found that most molecules inhibited Aspergillus at concentrations similar to that of PQS, but with relatively flat dose-responses, and all were less potent than PQS. The inhibition was reversible by iron, suggesting interference with fungal iron metabolism. Stimulation of Aspergillus was not noted. We conclude that the critical Aspergillus-inhibiting moeities of the PQS molecule were partially, but not completely, interfered with by molecular modifications at several sites on the PQS molecule. The mechanism, as with PQS, appears to relate to fungal iron metabolism.
Hasan Nazik; Gabriele Sass; Paul Williams; Eric Déziel; David Stevens. Molecular Modifications of the Pseudomonas Quinolone Signal in the Intermicrobial Competition with Aspergillus. Journal of Fungi 2021, 7, 343 .
AMA StyleHasan Nazik, Gabriele Sass, Paul Williams, Eric Déziel, David Stevens. Molecular Modifications of the Pseudomonas Quinolone Signal in the Intermicrobial Competition with Aspergillus. Journal of Fungi. 2021; 7 (5):343.
Chicago/Turabian StyleHasan Nazik; Gabriele Sass; Paul Williams; Eric Déziel; David Stevens. 2021. "Molecular Modifications of the Pseudomonas Quinolone Signal in the Intermicrobial Competition with Aspergillus." Journal of Fungi 7, no. 5: 343.
Aspergillus and Pseudomonas compete in nature, and are the commonest bacterial and fungal pathogens in some clinical settings, such as the cystic fibrosis lung. Virus infections of fungi occur naturally. Effects on fungal physiology need delineation. A common reference Aspergillus fumigatus strain, long studied in two (of many) laboratories, was found infected with the AfuPmV-1 virus. One isolate was cured of virus, producing a virus-free strain. Virus from the infected strain was purified and used to re-infect three subcultures of the virus-free fungus, producing six fungal strains, otherwise isogenic. They were studied in intermicrobial competition with Pseudomonas aeruginosa. Pseudomonas culture filtrates inhibited forming or preformed Aspergillus biofilm from infected strains to a greater extent, also seen when Pseudomonas volatiles were assayed on Aspergillus. Purified iron-chelating Pseudomonas molecules, known inhibitors of Aspergillus biofilm, reproduced these differences. Iron, a stimulus of Aspergillus, enhanced the virus-free fungus, compared to infected. All infected fungal strains behaved similarly in assays. We show an important consequence of virus infection, a weakening in intermicrobial competition. Viral infection may affect the outcome of bacterial–fungal competition in nature and patients. We suggest that this occurs via alteration in fungal stress responses, the mechanism best delineated here is a result of virus-induced altered Aspergillus iron metabolism.
Hasan Nazik; Ioly Kotta-Loizou; Gabriele Sass; Robert Coutts; David Stevens. Virus Infection of Aspergillus fumigatus Compromises the Fungus in Intermicrobial Competition. Viruses 2021, 13, 686 .
AMA StyleHasan Nazik, Ioly Kotta-Loizou, Gabriele Sass, Robert Coutts, David Stevens. Virus Infection of Aspergillus fumigatus Compromises the Fungus in Intermicrobial Competition. Viruses. 2021; 13 (4):686.
Chicago/Turabian StyleHasan Nazik; Ioly Kotta-Loizou; Gabriele Sass; Robert Coutts; David Stevens. 2021. "Virus Infection of Aspergillus fumigatus Compromises the Fungus in Intermicrobial Competition." Viruses 13, no. 4: 686.
Background: Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) compete with each other for nutrients and survival in natural environments, and have been extensively studied because of their intermicrobial interactions in the human microbiome. These are the principal microbes infecting immunocompromised patients and persons with cystic fibrosis, particularly the airways. These intermicrobial studies have largely been conducted in liquid medium or on agar, and thus focus on soluble or diffusible microbial products. Several key inhibitory molecules were defined in such studies. Methods: in the present report, we examine several methodologies which can be conveniently used to study the interaction of microbial volatiles, including capture methods and kinetics. Results: Pa volatiles inhibit Af, and the inhibitory mechanism appears to be the incorporation of the inhibitory molecules into the substrate nourishing the Af, rather than directly onto Af structures. We define by mass spectroscopy some specific volatile Pa products that can inhibit Af. Some of these molecules are selected for interest by the study of gene deletion mutants, producing a few Pa strains that were impaired in inhibition. We presumed the volatiles of these latter strains could be excluded from the search for inhibitors. Conclusion: the Pa inhibition of Af via a gaseous phase could be critical components in their competition, particularly in airways, where more direct contact may not be extensive.
Hasan Nazik; Gabriele Sass; Eric Déziel; David A. Stevens. Aspergillus Is Inhibited by Pseudomonas aeruginosa Volatiles. Journal of Fungi 2020, 6, 118 .
AMA StyleHasan Nazik, Gabriele Sass, Eric Déziel, David A. Stevens. Aspergillus Is Inhibited by Pseudomonas aeruginosa Volatiles. Journal of Fungi. 2020; 6 (3):118.
Chicago/Turabian StyleHasan Nazik; Gabriele Sass; Eric Déziel; David A. Stevens. 2020. "Aspergillus Is Inhibited by Pseudomonas aeruginosa Volatiles." Journal of Fungi 6, no. 3: 118.
Pseudomonas aeruginosa (Pa) and Candida albicans (Ca) are major bacterial and fungal pathogens in immunocompromised hosts, and notably in the airways of cystic fibrosis patients. The bacteriophages of Pa physically alter biofilms, and were recently shown to inhibit the biofilms of Aspergillus fumigatus. To understand the range of this viral–fungal interaction, we studied Pa phages Pf4 and Pf1, and their interactions with Ca biofilm formation and preformed Ca biofilm. Both forms of Ca biofilm development, as well as planktonic Ca growth, were inhibited by either phage. The inhibition of biofilm was reversed by the addition of iron, suggesting that the mechanism of phage action on Ca involves denial of iron. Birefringence studies on added phage showed an ordered structure of binding to Ca. Electron microscopic observations indicated phage aggregation in the biofilm extracellular matrix. Bacteriophage–fungal interactions may be a general feature with several pathogens in the fungal kingdom.
Hasan Nazik; Lydia-Marie Joubert; Patrick R. Secor; Johanna Sweere; Paul L. Bollyky; Gabriele Sass; Lynette Cegelski; David A. Stevens. Pseudomonas phage inhibition of Candida albicans. Microbiology 2017, 163, 1568 -1577.
AMA StyleHasan Nazik, Lydia-Marie Joubert, Patrick R. Secor, Johanna Sweere, Paul L. Bollyky, Gabriele Sass, Lynette Cegelski, David A. Stevens. Pseudomonas phage inhibition of Candida albicans. Microbiology. 2017; 163 (11):1568-1577.
Chicago/Turabian StyleHasan Nazik; Lydia-Marie Joubert; Patrick R. Secor; Johanna Sweere; Paul L. Bollyky; Gabriele Sass; Lynette Cegelski; David A. Stevens. 2017. "Pseudomonas phage inhibition of Candida albicans." Microbiology 163, no. 11: 1568-1577.
The paucity of effective antifungals against Aspergillus and increasing resistance, the recognition of the importance of Aspergillus biofilm in several clinical settings, and reports of verapamil—a calcium channel blocker—efficacy against Candida biofilm and hyphal growth, and synergy with an azole antifungal in vitro, led to a study of verapamil ± voriconazole against Aspergillus. Broth macrodilution methodology was utilized for MIC (minimum inhibitory concentration) and MFC (minimum fungicidal concentration) determination. The metabolic effects (assessed by XTT [2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt]) on biofilm formation by conidia were studied upon exposure to verapamil, verapamil plus voriconazole, or voriconazole alone. For biofilm formation, we found less inhibition from the combinations than with either drug alone, or less inhibition from the combination than that of the more potent drug alone. For preformed biofilm, we found no significant change in activity comparing voriconazole alone compared to added verapamil, and no significant alteration of activity of the more potent voriconazole, at any concentration in the range tested, by addition of a concentration of verapamil that is inhibitory alone. In full checkerboard assays with planktonic fungus, there was no indication of any effect of one drug on the other (indifference). Although verapamil was similarly inactive against planktonic Aspergillus, as with Candida, verapamil was indeed active against Aspergillus biofilm. However, indifference and antagonism was found with voriconazole.
Hasan Nazik; Varun Choudhary; David A. Stevens. Verapamil Inhibits Aspergillus Biofilm, but Antagonizes Voriconazole. Journal of Fungi 2017, 3, 50 .
AMA StyleHasan Nazik, Varun Choudhary, David A. Stevens. Verapamil Inhibits Aspergillus Biofilm, but Antagonizes Voriconazole. Journal of Fungi. 2017; 3 (3):50.
Chicago/Turabian StyleHasan Nazik; Varun Choudhary; David A. Stevens. 2017. "Verapamil Inhibits Aspergillus Biofilm, but Antagonizes Voriconazole." Journal of Fungi 3, no. 3: 50.
Nagehan Pakasticali; Gamze Kaya; Unal Senel; Oner Kipritci; Zeynep Tamay; Nermin Guler; Hasan Nazik; Betigul Ongen. PREVALENCE, ANTIBIOTIC AND PULSED-FIELD GEL ELECTROPHORESIS PATTERNS OF STAPHYLOCOCCUS AUREUS SMALL-COLONY VARIANTS IN CYSTIC FIBROSIS PATIENTS. The Southeast Asian journal of tropical medicine and public health 2016, 47, 1 .
AMA StyleNagehan Pakasticali, Gamze Kaya, Unal Senel, Oner Kipritci, Zeynep Tamay, Nermin Guler, Hasan Nazik, Betigul Ongen. PREVALENCE, ANTIBIOTIC AND PULSED-FIELD GEL ELECTROPHORESIS PATTERNS OF STAPHYLOCOCCUS AUREUS SMALL-COLONY VARIANTS IN CYSTIC FIBROSIS PATIENTS. The Southeast Asian journal of tropical medicine and public health. 2016; 47 (3):1.
Chicago/Turabian StyleNagehan Pakasticali; Gamze Kaya; Unal Senel; Oner Kipritci; Zeynep Tamay; Nermin Guler; Hasan Nazik; Betigul Ongen. 2016. "PREVALENCE, ANTIBIOTIC AND PULSED-FIELD GEL ELECTROPHORESIS PATTERNS OF STAPHYLOCOCCUS AUREUS SMALL-COLONY VARIANTS IN CYSTIC FIBROSIS PATIENTS." The Southeast Asian journal of tropical medicine and public health 47, no. 3: 1.
Nuray Kuvat; Hasan Nazik; Rahmiye Berkiten; Betigül Öngen. TEM-1 AND ROB-1 PRESENCE AND ANTIMICROBIAL RESISTANCE IN HAEMOPHILUS INFLUENZAE STRAINS, ISTANBUL, TURKEY. The Southeast Asian journal of tropical medicine and public health 2015, 46, 1 .
AMA StyleNuray Kuvat, Hasan Nazik, Rahmiye Berkiten, Betigül Öngen. TEM-1 AND ROB-1 PRESENCE AND ANTIMICROBIAL RESISTANCE IN HAEMOPHILUS INFLUENZAE STRAINS, ISTANBUL, TURKEY. The Southeast Asian journal of tropical medicine and public health. 2015; 46 (2):1.
Chicago/Turabian StyleNuray Kuvat; Hasan Nazik; Rahmiye Berkiten; Betigül Öngen. 2015. "TEM-1 AND ROB-1 PRESENCE AND ANTIMICROBIAL RESISTANCE IN HAEMOPHILUS INFLUENZAE STRAINS, ISTANBUL, TURKEY." The Southeast Asian journal of tropical medicine and public health 46, no. 2: 1.
Hasan Nazik; Selda Aydin; Rüveyda Albayrak; Esma A Bilgi; Ismail Yildiz; Nuray Kuvat; Fatih M Kelesoglu; Nagehan Pakaştiçali; Fadime Yilmaz; Betigül Ongen. Detection and spread of oxa-48-producing Klebsiella oxytoca isolates in Istanbul, Turkey. The Southeast Asian journal of tropical medicine and public health 2014, 45, 1 .
AMA StyleHasan Nazik, Selda Aydin, Rüveyda Albayrak, Esma A Bilgi, Ismail Yildiz, Nuray Kuvat, Fatih M Kelesoglu, Nagehan Pakaştiçali, Fadime Yilmaz, Betigül Ongen. Detection and spread of oxa-48-producing Klebsiella oxytoca isolates in Istanbul, Turkey. The Southeast Asian journal of tropical medicine and public health. 2014; 45 (1):1.
Chicago/Turabian StyleHasan Nazik; Selda Aydin; Rüveyda Albayrak; Esma A Bilgi; Ismail Yildiz; Nuray Kuvat; Fatih M Kelesoglu; Nagehan Pakaştiçali; Fadime Yilmaz; Betigül Ongen. 2014. "Detection and spread of oxa-48-producing Klebsiella oxytoca isolates in Istanbul, Turkey." The Southeast Asian journal of tropical medicine and public health 45, no. 1: 1.
The fate of suboptimal anastomosis is unknown and early detection of anastomotic leakage after colon resection is crucial for the proper management of patients. Twenty-six rats were assigned to "Control", "Leakage" and "Suboptimal anastomosis" groups where they underwent either sham laparotomy, cecal ligation, and puncture or anastomosis with four sutures following colon resection, respectively. At the fifth hour and on the third and ninth days; peripheral blood and peritoneal washing samples through relaparotomy were obtained. The abdomen was inspected macroscopically for anastomotic healing. Polymerase chain reaction (PCR) with 16s rRNA and E.coli-specific primers were run on all samples along with aerobic and anaerobic cultures. The sensitivity and specificity of PCR on different bodily fluids with 16s rRNA and E.coli-specific primers were 100% and 78%, respectively. All samples of peritoneal washing fluids on the third and ninth days showed presence of bacteria in both PCR and culture. The inspection of the abdomen revealed signs of anastomotic leakage in eight rats (80%), whereas mortality related with anastomosis was detected in two (20%). Anastomotic leakage with suboptimal anastomosis after colon resection is high and the early detection is possible by running PCR on peritoneal samples as early as 72 hours.
Mehmet Kamil Yildiz; Ismail Okan; Hasan Nazik; Gurhan Bas; Orhan Alimoglu; Mehmet Ilktac; Emin Daldal; Mustafa Sahin; Nuray Kuvat; Betugul Ongen. The fate of suboptimal anastomosis after colon resection: an experimental study. Turkish Journal of Trauma and Emergency Surgery 2014, 20, 401 -409.
AMA StyleMehmet Kamil Yildiz, Ismail Okan, Hasan Nazik, Gurhan Bas, Orhan Alimoglu, Mehmet Ilktac, Emin Daldal, Mustafa Sahin, Nuray Kuvat, Betugul Ongen. The fate of suboptimal anastomosis after colon resection: an experimental study. Turkish Journal of Trauma and Emergency Surgery. 2014; 20 (6):401-409.
Chicago/Turabian StyleMehmet Kamil Yildiz; Ismail Okan; Hasan Nazik; Gurhan Bas; Orhan Alimoglu; Mehmet Ilktac; Emin Daldal; Mustafa Sahin; Nuray Kuvat; Betugul Ongen. 2014. "The fate of suboptimal anastomosis after colon resection: an experimental study." Turkish Journal of Trauma and Emergency Surgery 20, no. 6: 401-409.
Hasan Nazik; Betigul Ongen; Mehmet Ilktac; Selda Aydin; Nuray Kuvat; Aysegul Sahin; Mucahit Yemisen; Bilgul Mete; Mehmet Sait Durmus; Ilker Inanc Balkan; Ismail Yildiz; Yakup Ergul. Carbapenem resistance due to Bla(OXA-48) among ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates in a univesity hospital, Turkey. The Southeast Asian journal of tropical medicine and public health 2012, 43, 1 .
AMA StyleHasan Nazik, Betigul Ongen, Mehmet Ilktac, Selda Aydin, Nuray Kuvat, Aysegul Sahin, Mucahit Yemisen, Bilgul Mete, Mehmet Sait Durmus, Ilker Inanc Balkan, Ismail Yildiz, Yakup Ergul. Carbapenem resistance due to Bla(OXA-48) among ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates in a univesity hospital, Turkey. The Southeast Asian journal of tropical medicine and public health. 2012; 43 (5):1.
Chicago/Turabian StyleHasan Nazik; Betigul Ongen; Mehmet Ilktac; Selda Aydin; Nuray Kuvat; Aysegul Sahin; Mucahit Yemisen; Bilgul Mete; Mehmet Sait Durmus; Ilker Inanc Balkan; Ismail Yildiz; Yakup Ergul. 2012. "Carbapenem resistance due to Bla(OXA-48) among ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates in a univesity hospital, Turkey." The Southeast Asian journal of tropical medicine and public health 43, no. 5: 1.
Mehmet Ilktac; Aysegul Sahin; Hasan Nazik; Betigul Ongen. Investigation of Rotavirus Frequency and Following up the Rotavirus Season among Children with Acute Gastroenteritis: Evaluation of Five-year Results. ANKEM DERGİSİ 2012, 26, 25 -29.
AMA StyleMehmet Ilktac, Aysegul Sahin, Hasan Nazik, Betigul Ongen. Investigation of Rotavirus Frequency and Following up the Rotavirus Season among Children with Acute Gastroenteritis: Evaluation of Five-year Results. ANKEM DERGİSİ. 2012; 26 (1):25-29.
Chicago/Turabian StyleMehmet Ilktac; Aysegul Sahin; Hasan Nazik; Betigul Ongen. 2012. "Investigation of Rotavirus Frequency and Following up the Rotavirus Season among Children with Acute Gastroenteritis: Evaluation of Five-year Results." ANKEM DERGİSİ 26, no. 1: 25-29.
H Nazik; B Öngen; B Mete; S Aydin; M Yemişen; F M Keleşoğlu; Y Ergul; F Tabak. Coexistence of blaOXA48andaac(6′)-Ib-crGenes inKlebsiella PneumoniaeIsolates from Istanbul, Turkey. Journal of International Medical Research 2011, 39, 1932 -1940.
AMA StyleH Nazik, B Öngen, B Mete, S Aydin, M Yemişen, F M Keleşoğlu, Y Ergul, F Tabak. Coexistence of blaOXA48andaac(6′)-Ib-crGenes inKlebsiella PneumoniaeIsolates from Istanbul, Turkey. Journal of International Medical Research. 2011; 39 (5):1932-1940.
Chicago/Turabian StyleH Nazik; B Öngen; B Mete; S Aydin; M Yemişen; F M Keleşoğlu; Y Ergul; F Tabak. 2011. "Coexistence of blaOXA48andaac(6′)-Ib-crGenes inKlebsiella PneumoniaeIsolates from Istanbul, Turkey." Journal of International Medical Research 39, no. 5: 1932-1940.
Orhan Baylan; Hasan Nazik; Bayhan Bektöre; Burak Ekrem Citil; Deniz Turan; Betigül Ongen; Mustafa Ozyurt; Cengiz Han Açıkel; Tunçer Haznedaroğlu. [The relationship between antibiotic resistance and virulence factors in urinary Enterococcus isolates]. Mikrobiyoloji Bulteni 2011, 45, 1 .
AMA StyleOrhan Baylan, Hasan Nazik, Bayhan Bektöre, Burak Ekrem Citil, Deniz Turan, Betigül Ongen, Mustafa Ozyurt, Cengiz Han Açıkel, Tunçer Haznedaroğlu. [The relationship between antibiotic resistance and virulence factors in urinary Enterococcus isolates]. Mikrobiyoloji Bulteni. 2011; 45 (3):1.
Chicago/Turabian StyleOrhan Baylan; Hasan Nazik; Bayhan Bektöre; Burak Ekrem Citil; Deniz Turan; Betigül Ongen; Mustafa Ozyurt; Cengiz Han Açıkel; Tunçer Haznedaroğlu. 2011. "[The relationship between antibiotic resistance and virulence factors in urinary Enterococcus isolates]." Mikrobiyoloji Bulteni 45, no. 3: 1.
Hasan Nazik; Bayhan Bektöre; Betigül Öngen; Mustafa Özyurt; Orhan Baylan; Tunçer Haznedaroğlu. Co-expression of plasmid-mediated quinolone resistance-qnrA1 and blaVEB-1 gene in a Providencia stuartii strain. The new microbiologica 2011, 34, 1 .
AMA StyleHasan Nazik, Bayhan Bektöre, Betigül Öngen, Mustafa Özyurt, Orhan Baylan, Tunçer Haznedaroğlu. Co-expression of plasmid-mediated quinolone resistance-qnrA1 and blaVEB-1 gene in a Providencia stuartii strain. The new microbiologica. 2011; 34 (2):1.
Chicago/Turabian StyleHasan Nazik; Bayhan Bektöre; Betigül Öngen; Mustafa Özyurt; Orhan Baylan; Tunçer Haznedaroğlu. 2011. "Co-expression of plasmid-mediated quinolone resistance-qnrA1 and blaVEB-1 gene in a Providencia stuartii strain." The new microbiologica 34, no. 2: 1.
Objective: Today, carbapenems are used as almost last choice for the treatment of infections with extended spectrum ?-lactamase (ESBL) producing pathogens. However, the prevalence of carbapenamase-producing strains in Enterobacteriaceae has been increasing over the last decade. In this study, carbapenem-resistant Escherichia coli and Citrobacter koseri isolates with OXA-48 carbapenemase obtained from hospitalized patients in different regions of Istanbul were investigated. Material and Methods: The strains were identified by conventional methods and VITEK 2 system. Antibiotic susceptibility test was performed using disc diffusion method, and extended-spectrum ?-lactamase production was investigated using the double-disc synergy and cefotaxime/boronic acid- cefotaxime/boronic acid/clavulanic acid tests. VITEK 2 system was used for determination of minimum inhibitory concentration (MIC) of the antibiotics. The MICs of imipenem and meropenem for the clinical isolates were also determined by E-tests. The carbapenemase production was investigated with modified Hodge test. ?-lactamase genes and plasmid mediated quinolone resistance (PMQR) determinants were screened by polymerase chain reaction (PCR). The amplification products of blaOXA-48 genes were sequenced. Conjugation experiment was used for transferring ?-lactamase gene. Results: The clinical isolates and their transconjugants were positive for blaOXA-48, however, the isolates lacked PMQR and other ?-lactamase genes such as blaTEM, blaSHV, blaCTX-M, blaVIM, blaIMP and blaKPC. The blaOXA-48 genes detected in both of the isolates were transferred to the recipient strain. The MICs were increased approximately two fold according to recipient strain in transconjugants for carbapenems. Additionally, the transconjugants conferred resistance to ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam and cefazolin. Conclusions: The carbapenemase-producing isolates may restrict the use of these valuable antibiotics. In Turkey, the blaOXA-48 gene not only persists especially in Klebsiella pneumoniae but also it has spread among other species. The presence of OXA-48 carbapenemase in rarely encountered species should also be considered.
Hasan Nazik; Bayhan Bektöre; Betigül Öngen; Mustafa Özyurt; Halil Yazici; Orhan Baylan; Tunçer Haznedaroğlu. Determination of Escherichia coli and Citrobacter koseri Isolates with OXA-48 Carbapenemase in İstanbul. Turkiye Klinikleri Journal of Medical Sciences 2011, 31, 1502 -1506.
AMA StyleHasan Nazik, Bayhan Bektöre, Betigül Öngen, Mustafa Özyurt, Halil Yazici, Orhan Baylan, Tunçer Haznedaroğlu. Determination of Escherichia coli and Citrobacter koseri Isolates with OXA-48 Carbapenemase in İstanbul. Turkiye Klinikleri Journal of Medical Sciences. 2011; 31 (6):1502-1506.
Chicago/Turabian StyleHasan Nazik; Bayhan Bektöre; Betigül Öngen; Mustafa Özyurt; Halil Yazici; Orhan Baylan; Tunçer Haznedaroğlu. 2011. "Determination of Escherichia coli and Citrobacter koseri Isolates with OXA-48 Carbapenemase in İstanbul." Turkiye Klinikleri Journal of Medical Sciences 31, no. 6: 1502-1506.
Amaç: Hastane kaynaklı genişlemiş spektrumlu beta-laktamaz (GSBL) oluşturan suşlar, yüksek ve çoklu antibiyotik dirençlilik özelliğine sahip olabilmektedir. Bu direnç, özellikle hayatı tehdit eden enfeksiyonlarda uygun antibiyotik seçiminin sınırlı olmasından dolayı tedavide güçlüklere yol açmaktadır. Bu çalışmada, hastanemizde izole edilen hastane kaynaklı Escherichia coli suşlarının imipenem, siprofloksasin, gentamisin ve ko-trimoksazole ait direnç profillerinin araştırılması amaçlanmıştır. Gereç ve Yöntemler: Üçüncü basamak sağlık merkezi olan hastanemizde 2006-2008 yılları arasında yatarak tedavi görmüş hastalara ait çeşitli klinik örneklerden izole edilen ve enfeksiyon etkeni oldukları düşünülen toplam 974 E.coli suşu çalışmaya dahil edilmiştir. Antibiyotik duyarlılık testi, Klinik ve Laboratuar Standardlar Enstitüsünün (Clinical and Laboratory Standards Institute, CLSI) önerileri doğrultusunda disk difüzyon yöntemi ile yapılmıştır. GSBL üretiminin saptanmasında çift disk sinerji testi kullanılmıştır. Aynı hastaya ait farklı klinik örneklerden izole edilmiş ancak aynı duyarlılık paternine sahip E.coli kökenleri çalışmaya dahil edilmemiştir. Bulgular: Üç yıllık süre içerisinde incelenen tüm suşların ko-trimoksazol ve siprofloksasine direnç oranlarının sırasıyla %53.5 ve %51.8 olduğu belirlenmiştir. Çalışmaya dahil edilen suşların 205 (%21)'inde GSBL üretimi saptanmıştır. GSBL üreten suşlarda ko-trimoksazol, siprofloksasin ve gentamisin direnci, GSBL üretmeyenlere göre anlamlı olarak yüksek bulunmuştur (p< 0.001). 2007'den 2008'e gentamisin direncindeki %27.8'den %35.5'e, GSBL üretimindeki %18'den %27'ye yükselme, anlamlı bulunmuştur (p< 0.05). Beş suşta imipenem direnci belirlenmiştir. Çoklu ilaç direnci, %19.2; ko-rezistans fenotipi ise %45.5 oranında bulunmuştur. Sonuç: Çalışmamızda hastane kökenli E.coli suşlarımız için imipenemin en etkili antibiyotik olduğu ve farklı gruptan antibiyotiklerden olan ko-trimoksazol, siprofloksasin ve gentamisine olan direncin ise özellikle GSBL üreten suşlarda yüksek olduğu belirlenmiştir. Bölgemizde ko-trimoksazol, siprofloksasin ve gentamisin ile başlanan ampirik tedavinin hastane kökenli E.coli suşlarında yetersiz kalabileceği sonucuna varılmıştır.
Hasan Nazik; Mustafa Özyurt; Orhan Baylan; Uğur Demirpek; Fatih Ermiş; Tunçer Haznedaroğlu. Investigation of Imipenem, Ciprofloxacin, Gentamicin and Co-trimoxazole Resistant Phenotypes in Nosocomial Escherichia coli Strains. Turkiye Klinikleri Journal of Medical Sciences 2011, 31, 39 -44.
AMA StyleHasan Nazik, Mustafa Özyurt, Orhan Baylan, Uğur Demirpek, Fatih Ermiş, Tunçer Haznedaroğlu. Investigation of Imipenem, Ciprofloxacin, Gentamicin and Co-trimoxazole Resistant Phenotypes in Nosocomial Escherichia coli Strains. Turkiye Klinikleri Journal of Medical Sciences. 2011; 31 (1):39-44.
Chicago/Turabian StyleHasan Nazik; Mustafa Özyurt; Orhan Baylan; Uğur Demirpek; Fatih Ermiş; Tunçer Haznedaroğlu. 2011. "Investigation of Imipenem, Ciprofloxacin, Gentamicin and Co-trimoxazole Resistant Phenotypes in Nosocomial Escherichia coli Strains." Turkiye Klinikleri Journal of Medical Sciences 31, no. 1: 39-44.
Hasan Nazik; Betigül Ongen; Nuray Kuvat. Investigation of plasmid-mediated quinolone resistance among isolates obtained in a Turkish intensive care unit. Japanese Journal of Infectious Diseases 2008, 61, 1 .
AMA StyleHasan Nazik, Betigül Ongen, Nuray Kuvat. Investigation of plasmid-mediated quinolone resistance among isolates obtained in a Turkish intensive care unit. Japanese Journal of Infectious Diseases. 2008; 61 (4):1.
Chicago/Turabian StyleHasan Nazik; Betigül Ongen; Nuray Kuvat. 2008. "Investigation of plasmid-mediated quinolone resistance among isolates obtained in a Turkish intensive care unit." Japanese Journal of Infectious Diseases 61, no. 4: 1.