Hasan Nazik

Istanbul University, İstanbul, Istanbul, Turkey

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Publications (24)19.95 Total impact

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    ABSTRACT: Resistance of 235 Haemophilus influenzae clinical isolates from Istanbul Medical Faculty Hospital, Turkey were determined against 19 antibiotics by disc diffusion method, and minimum inhibitory concentrations (MICs) of those found resistant to ampicillin, cefuroxim, chloramphenicol and meropenem were measured using E-test. Ampicillin-resistant isolates producing beta-lactamase as demonstrated by a nitrocefin assay were analyzed for the presence of TEM-1 and ROB-1 genes by PCR. Eleven percent of the isolates were resistant to ampicillin (10 mu g/ml), of which 73% were beta-lactamase positive and carried TEM-1 gene, but none were positive for ROB-1 gene. All isolates susceptible to amoxicillin-clavulanate (20/10 mu g/ml), azithromycin (15 mu g/ml), aztreonam (30 mu g/ml), cefotaxime (30 mu g/ml), ceftriaxone (30 mu g/ml), ciprofloxacin (5 mu g/ml) levofloxacin (5 mu g/ml), and telithromycin (15 mu g/ml) but 24%, 15%, 4%, 4%, 2%, 1%, 1%, 0.5%, 0.5% and 0.5% were resistant to trimethoprim-sulfamethoxazole (1.25/23.75 mu g/ml), tetracycline (30 mu g/ml), cefaclor (30 mu g/ml), clarithromycin (15 mu g/ml), cefuroxime (30 mu g/ml), meropenem (10 mu g/ml), chloramphenicol (30 mu g/ml), ampicillin-sulbactam (10/10 mu g/ml), nalidixic acid (30 mu g/ml), and fosfomycin (30 mu g/ml), respectively. MIC values of three cefuroxime-resistant isolates was 24, 48 and > 256 mu g/ml, respectively; of two meropenem-resistant strains > 256 mu g/ml; and of two chloramphenicol-susceptible isolates (by disc diffusion method) 6 mu g/ml (considered as intermediate susceptible). Multiple-antibiotics resistance was detected in 15% of the strains, with resistance to 2, 3, 4, 5 and 6 antibiotics in 8.5%, 4%, 2%, 0.5% and 0.5% of the isolates, respectively. By identifying beta-lactamase-negative ampicillin-resistant H. influenzae, empirical therapy with beta-lactam/beta-lactamase inhibitor combinations and second generation cephalosporins would be inappropriate for such patients (approximately 3%). Our findings will contribute to the epidemiological and clinical data regarding H. influenzae infection in Turkey.
    The Southeast Asian journal of tropical medicine and public health 03/2015; 46(2):254-261. · 0.55 Impact Factor
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    ABSTRACT: 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.
    Ulusal travma ve acil cerrahi dergisi = Turkish journal of trauma & emergency surgery: TJTES 11/2014; 20(6):401-409. DOI:10.5505/tjtes.2014.31899 · 0.38 Impact Factor
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    ABSTRACT: Five OXA-48 producing Klebsiella oxytoca strains isolated in April-July 2010 were analyzed. Antibiotic susceptibility tests were performed using disc diffusion method and VITEK 2 system. Carbapenemase activity was investigated using the Modified Hodge test. Beta-lactamase genes were detected by PCR and blaOXA-48 was sequenced. Genetic relatedness between K. oxytoca isolates was investigated by pulse-field gel electrophoresis (PFGE). Carbapenemase activity was detected in 5 isolates by Modified Hodge test. Although all strains were resistant to ertapenem and imipenem, only one strain was also resistant to meropenem. BlaOXA-48 in 4 isolates harbored 2 or 3 other ESBL types, namely, blaTEM, blaSHV, blaCTX-M, or blaVEB. PFGE revealed 3 different pulso-types among the K. oxytoca isolates. The presence of OXA-48 carbapenemase in other species of clinical isolates should also be considered.
    The Southeast Asian journal of tropical medicine and public health 01/2014; 45(1):123-9. · 0.55 Impact Factor
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    ABSTRACT: Aeromonas species isolated from stool cultures and their susceptibilities to various antibiotics B. Ongen1 *, M. Ilktac1, A. Aydın1, H. Nazik1. 1Medical Microbiology Department, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey E-mail address : ongenb@gmail.com Introduction: Aeromonas spp. are emerging agents of gastroenteritis. Since most of the species produce inducible type chromosomal beta�lactamase, resistance can develop during beta-lactam therapy [1]. Objectives: It was aimed to investigate the frequency of Aeromonas spp. in stool samples of patients with gastroenteritis between January 2007 and June 2012 and to determine their antibiotic susceptibilities. Methods: Stool samples were inoculated onto 5% sheep blood agar, MacConkey agar, Hektoen enteric agar, selenite F and Gram negative broth. Media were incubated aerobically at 35–37°C. Oxidase positive Gram negative rods on blood agar were investigated for Aeromonas spp. by API 32 GN and VITEK 2 systems (bioM´erieux). Amoxicillin–clavulanic acid, ampicillin–sulbactam, piperacillin–tazo�bactam, cefoxitine, cefotaxime, ceftazidime, cefepime, imipenem, meropenem, ertapenem, aztreonam, gentamicin, amikacin, cipro- floxacin, levofloxacin, co-trimoxazole, tetracycline and chloramphe�nicol susceptibilities were determined by disc diffusion method according to CLSI M45-A2 criteria [2]. Results: 60 (0.6%) Aeromonas spp. were isolated from 10,666 stool samples. Between 2007–2012; Aeromonas spp. was isolated at the rates of 0.4%, 0.12%, 0.45%, 0.2%, 1.1% and 0.7% respectively. Forty�three (72%) isolates were identified as A. hydrophila/caviae, 8 (13%) as A. sobria, 3 (5%) as A. veronii and 6 (10%) as Aeromonas spp. Polymorphonuclear leukocytes were positive for 25% of the samples in which Aeromonas was isolated. Of the stool samples in which Aeromonas spp. was isolated, approximately ¾ were watery with mucus and 6% were watery with blood and mucus. Antibiotic susceptibility testing was carried out for 52 isolates and all isolates were found to be susceptible to imipenem, meropenem and cefepime. The highest resistance rate was for ampicillin– sulbactam (92%) followed by amoxicillin–clavulanic acid (63%) and co-trimoxazole (37%). Except for tetracycline (19.2%) and cefoxitin (13.5%), resistance rates of other antibiotics were found to be lower than 10%. Conclusion: As a result, in diarrheagenic patients, the presence of Aeromonas spp. and their antibiotic susceptiblities should be followed up. Reference(s) [1] Horneman AJ, Ali A. Aeromonas . In Versalovic J, Carroll KC, Funke, G, Jorgensen JH, Landry M,Warnock DW (eds): Manual of Clinical Microbiology, 10th ed. ASM Press, Washington (2011). [2] Clinical Laboratory Standards Institute (CLSI). Methods for antimicrobial dilution and disk susceptibility testing of infrequently isolated or fastidious bacteria; Approved guideline, 2nd ed. M45-A2. Wayne PA: CLSI (2010).
    International Journal of Antimicrobial Agents; 06/2013
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    Turkiye Klinikleri Journal of Medical Sciences 01/2013; 33(2):560-563. DOI:10.5336/medsci.2011-25296 · 0.10 Impact Factor
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    ABSTRACT: Bacterial isolates producing Class D OXA-48 carbapenemase may be missed in routine laboratory testing, allowing them to spread undetected. The purpose of the present study was to detect bla(OXA-48) among ESBL-producing Klebsiella pneumoniae and Escherichia coli isolates collected from a university hospital, Turkey. Ninety-two ESBL-producing isolates (66 E. coli, 26 K. pneumoniae) were obtained in 2010. Antibiotic susceptibility tests were performed using the disc diffusion method and VITEK 2 system. Carbapenemase activity was screened using modified Hodge test. Beta-lactamase genes were detected by PCR and bla(OXA-48)-positive amplicons were sequenced. Genetic relatedness among K. pneumoniae isolates was investigated by pulsed-field gel-electrophoresis (PFGE). Carbapenemase activity was detected in 1 E. coli and 9 K. pneumoniae isolates and 8 of the K. pneumoniae plus the E. coli isolates were resistant to ertapenem. Three K. pneumoniae and 1 E. coli isolates were resistant to imipenem. All 10 isolates were susceptible to meropenem. bla(OXA-48) was present in all 10 isolates. Additionally, 9 isolates contained at least one beta-lactamase gene, including bla(SHV') bla(CTX-M) and bla(VEB) type. PFGE revealed different karyotypes among 9 K. pneumoniae isolates suggesting that the dissemination of bla(OXA-48) gene was not spread by a single K. pneumoniae clone. Thus OXA-48-producing isolates found in carbapenem-susceptible strains according to CLSI guidelines.
    The Southeast Asian journal of tropical medicine and public health 09/2012; 43(5):1178-85. · 0.55 Impact Factor
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    ABSTRACT: Gastroenterology units have faced a major increase in referrals for PEG insertion over the last decade. For this reason we decided to review our PEG insertion procedures with regard to indications, complications and follow-up. The indications, success of procedure, complications, long-term results of PEG in patients of Gulhane Military Medical Academy, Haydarpasa Training Hospital between October 2002 and April 2009 were retrospectively evaluated. 81 patients had undergone PEG insertion and follow-up information has been available for 77 patients. 40 were men with the mean age of all patients 70.74 ± 20.82 (range 20 to 104 years). PEG was successfully placed in all patients except in one patient who had gastric bleeding during the procedure. There was only one mortality related with the placement procedure. The most common indication for PEG was neurologic disorders in 71 (92%) patients. Other indications were head and neck cancers in 6 (8%) patients. Median follow-up period was 12 months (range, 3 days to 78 months). PEG related complications were seen in only 14 patients (18.2%) in 16 events with a total complication rate as 21%. PEG placement is a safe procedure and well-tolerated with a low mortality and complication rate even in older patients who have multiple co-morbidities under adequate precautions.
    Wiener klinische Wochenschrift 03/2012; 124(5-6):148-53. DOI:10.1007/s00508-011-0082-0 · 0.79 Impact Factor
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    ABSTRACT: A AB BS S T TR RA AC CT T O Ob bj je ec ct ti iv ve e: : Today, carbapenems are used as almost last choice for the treatment of infections with ex-tended spectrum β-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 re-gions of Istanbul were investigated. M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : The strains were identified by conventional methods and VITEK 2 system. Antibiotic susceptibility test was performed using disc diffusion method, and extended-spectrum β-lactamase production was investigated using the double-disc synergy and cefotaxime/boronic acid-cefo-taxime/boronic acid/clavulanic acid tests. VITEK 2 system was used for determination of minimum inhibitory con-centration (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. β-lactamase genes and plasmid mediated quinolone resistance (PMQR) determinants were screened by polymerase chain reaction (PCR). The amplification products of bla OXA-48 genes were sequenced. Conjugation experiment was used for transferring β-lactamase gene. R Re es su ul lt ts s: : The clinical isolates and their transconjugants were positive for bla OXA-48 , however, the iso-lates lacked PMQR and other β-lactamase genes such as bla TEM , bla SHV , bla CTX-M , bla VIM , bla IMP and bla KPC . The bla OXA-48 genes detected in both of the isolates were transferred to the recipient strain. The MICs were increased ap-proximately two fold according to recipient strain in transconjugants for carbapenems. Additionally, the transcon-jugants conferred resistance to ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam and cefazolin. C Co on nc cl lu us si io on ns s: : The carbapenemase-producing isolates may restrict the use of these valuable antibiotics. In Turkey, the bla OXA-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. K Ke ey y W Wo or rd ds s: : Carbapenemase; Escherichia coli; Citrobacter koseri; oxacillinase Ö ÖZ ZE ET T A Am ma aç ç: : Günümüzde, karbapenemler geniş spektrumlu β-laktamaz (ESBL) üreten patojenlerlerin neden olduğu enfeksiyonların tedavisi için genellikle son tercih olarak kullanılmaktadır. Bununla birlikte Enterobacteriaceae içinde karbapenemaz üreten türlerin prevalansı son on yılda artış göstermektedir. Bu çalışmada, İstanbul'un farklı böl-gelerinde hastaneye yatmış olan hastalardan izole edilen, OXA-48 karbapenamazı üreten karbapenem dirençli Es-cherichia coli ve Citrobacter koseri izolatları incelenmiştir. G Ge er re eç ç v ve e Y Yö ön nt te em ml le er r: : Suşlar, konvansiyonel yöntemler ve VITEK 2 sistemi ile identifiye edilmiştir. Antibiyotik duyarlılık testleri, disk difüzyon yöntemi kullanılarak uygu-lanmış ve genişlemiş spektrumlu β-laktamaz üretimi, çift disk sinerji ve sefotaksim/boronik asit-sefotaksim/boronik asit/klavulanik asit testleri kullanılarak araştırılmıştır. Antibiyotiklerin minimum inhibitor konsantrasyonunun (MİK) saptanmasında VITEK 2 sistemi kullanılmıştır. Klinik izolatların imipenem ve meropenem için MİK'leri, E-test yön-temi ile de saptanmıştır. Karbapenemaz üretimi, modifiye Hodge testi ile araştırılmıştır. β-laktamaz genleri ve plazmid aracılı kinolon direnci (PMQR) determinanları, polimeraz zincir reaksiyonu ile taranmıştır. bla OXA-48 genlerinin am-plifikasyon ürünleri sekanslanmıştır. β-laktamaz gen transferi için konjugasyon deneyi kullanılmıştır. B Bu ul lg gu ul la ar r: : Klinik izolatlar ve transkonjuganlarında, bla OXA-48 geni pozitif bulunmuş ancak PMQR ve bla TEM , bla SHV , bla CTX-M , bla VIM , bla IPM ve bla KPC gibi diğer β-laktamaz genleri saptanmamıştır. Heriki izolatta saptanan bla OXA-48 geni, alıcı bakteriye aktarılmıştır. Trankonjuganlarda karbapenemler için saptanan MİK değerleri alıcı bakteriye göre iki kat daha yük-sek bulunmuştur. Buna ek olarak transkonjuganlar ampisilin, amoksisilin-klavulanik asid, piperasilin-tazobaktam ve sefazoline direnç gösterdiği saptanmıştır. S So on nu uç ç: : Karbapenemaz üreten suşlar karbapenemlerin kullanınımını sınır-layabilmektedir. Türkiye'de OXA-48 geni özellikle Klebsiella pneumoniae suşlarında bulunmaya devam etmekte, ayrıca diğer suşlar arasında da yayılmaktadır. OXA-48 karbapenemazının varlığı seyrek karşılaşılan türlerde de akla getirilmelidir A An na ah h t ta ar r K Ke e l li i m me e l le er r: : Carbapenemase; Escherichia coli; Citrobacter koseri; oxacillinase
    Turkiye Klinikleri Journal of Medical Sciences 12/2011; 31(6):1502-6. DOI:10.5336/medsci.2010-22148 · 0.10 Impact Factor
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    ABSTRACT: This study evaluated the presence of carbapenem hydrolysing β-lactamase genes and plasmid-mediated quinolone resistance (PMQR) determinants in 22 Klebsiella pneumoniae isolates collected from the Istanbul Medical Faculty, Turkey, which reduced the susceptibility or resistance to carbapenem. The VITEK® 2 system and E-tests were used to determine the minimum inhibitory concentrations needed to inhibit bacterial growth. Genes were screened by polymerase chain reaction, and gene transferability was evaluated by transconjugation. Strain clonality was investigated by pulsed-field gel electrophoresis (PFGE). All strains were OXA-48 β-lactamase producers and three (13.6%) were also positive for the aac(6′)-Ib-cr gene. Most of the strains harboured other b-lactamase (bla) genes such as blaTEM, blaSHV, blaCTX-M and blaVEB-1. The transconjugants mostly harboured blaOXA-48 and other β-lactamases separately. PFGE revealed eight pulsotypes among the isolates. The coexistence of blaOXA-48 and PMQR in K. pneumoniae isolates may present a significant threat to health, especially in the nosocomial setting.
    The Journal of international medical research 10/2011; 39(5):1932-1940. DOI:10.1177/147323001103900538 · 1.10 Impact Factor
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    ABSTRACT: IntroductionTuberculosis involving small tubular bones like the metacarpus, metatarsus and the phalanx (tuberculous dactylitis) is a rare form of the disease. Tuberculous dactylitis may sometimes be confused with chronic osteomyelitis, metabolic disorders, sarcoidosis or malignancies, and when the correct diagnosis is made at a later stage of disease progression, severe deformities will have already occurred in the affected bones. Case presentationIn this case report, we present the severe deformation of a phalanx affected by tuberculous dactylitis, which has been diagnosed and treated approximately 3months later than the first presentation 10years ago. KeywordsTuberculous dactylitis–Phalanx–Index finger
    10/2011; 2(3):97-99. DOI:10.1007/s12570-011-0060-z
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    ABSTRACT: First-line standard eradication efficacy with lansoprazole, amoxicillin and clarithromycin regressed over 10 years. The aim of this study was to evaluate the efficacy and tolerability of a levofloxacin-based regimen in patients with peptic ulcer after failure of the standard first-line H.pylori eradication therapy in a country with a high rate of infection. A total of 91 peptic ulcer patients who were diagnosed H.pylori positive proven by rapid urease test and histology between November 2005 to March 2008 were given lansoprazole 30 mg bid, amoxicillin 1 g bid and clarithromycin 500 mg bid (LAC) for 14 days. After three months from the first line eradication treatment omeprazole 20 mg bid, levofloxacin 500 mg bid, amoxicillin 1 g bid (OLA) 7 day treatment regimen was recommended as a second-line therapy for 37 patients who failed at first-line standard triple therapy. Eradication rates for LAC regimen were found to be 57.14% (52/91) for intention to treat and 58.42% (52/89) for per protocol analysis. Eradication rates for OLA regimen were found to be 37.83% (14/37) for ITT and 41.17% (14/34) for PP analysis. OLA regimen eradication rate was successful only in 40% of patients who failed in the first-line eradication. New eradication treatment strategies must be performed, at least in Turkey.
    Southern medical journal 08/2011; 104(8):579-83. DOI:10.1097/SMJ.0b013e3182249be0 · 1.12 Impact Factor
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    ABSTRACT: Purpose: To evaluate the occurrence of plasmid-mediated quinolone resistance (PMQR) genes and the prevalence of extended spectrum beta-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed using the disc diffusion method. ESBL production was determined using a double-disc synergy test for all isolates; E-test and Vitek 2 were used for plasmid-mediated quinolone resistance (PMQR)-positive isolates and their transconjugants. The presence of PMQR and beta-lactamase genes was determined by polymerase chain reaction (PCR). Results: The strains displayed high rates of resistance to norfloxacin (80%). The most frequent PMQR gene was aac(6’)-Ib-cr (45.9%). In all, one qnrA1 (1.6%), one qnrS1 (1.6%), and two qepA1-positive isolates (5.7%) were identified. The genes, qnrS1+aac(6’)-Ib-cr and qepA1, were co-expressed with blaCTX-M-15 gene, while qnrA1 occurred with blaTEM-1, blaSHV, and blaVEB-1 genes. The most frequent beta-lactamase type was cefotaximase (CTX-M), which generally hydrolyzes cefotaxime (92%) more than it does ceftazidime; followed by temoneira (TEM, 39%); sulfhydryl variable (SHV, 5%), and Vietnamese extended-spectrum beta-lactamase (VEB, 1.6%). Conclusion: A high prevalence of aac(6’)-Ib-cr and CTX-M type beta-lactamase was detected in ESBL producing E.coli strains. This study also identified the co-expression of qnrA1 and blaVEB-1 genes and of qnrS1+aac(6’)-Ib-cr in E.coli isolates. The co-existence of PMQR genes with ESBLs may lead to a serious public health problem.
    Tropical Journal of Pharmaceutical Research 07/2011; 10(3):325-333. DOI:10.4314/tjpr.v10i3.9 · 0.50 Impact Factor
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    ABSTRACT: Increasing multidrug resistance in nosocomial Enterococcus strains from all over the world recently enhances the need for further investigation of enterococci, especially their virulence factors. There are still many lacking parts about virulence factors of clinical enterococcus isolates. In this study, it was aimed to investigate the antibiotic resistance and the presence of potential virulence factors of 91 Enterococcus strains (59 E.faecalis, 31 E.faecium and 1 E.gallinarum) isolated from urine cultures of inpatients between January 2008-June 2010 in our hospital and also to evaluate whether a correlation existed between antibiotic resistance and potential virulence factors. The genes which encoded virulence factors of enterococci; aggregation substance (AS), enterococcal surface protein (ESP) and hyaluronidase (HYL) (asa1, esp, hyl respectively) were studied by molecular methods and haemolysin production and gelatinase activity were studied by phenotypic methods. Vancomycin resistant strains were checked for the presence of vanA and vanB genes. Eight (25.8%) E.faecium isolates were found glycopeptide resistant. In seven of these isolates resistance type was vanA and in one it was neither vanA nor vanB. High-level gentamicin and high-level streptomycin resistance rates were 74.2% and 61.3% in E.faecium strains and were 22% ve 27.1% in E.faecalis strains, respectively. Beta-lactamase production and linezolid resistance were not detected in any of the strains. E.faecium isolates were more resistant (p< 0.001-0.013) than E.faecalis isolates to all tested antibiotics except tetracycline, minocycline, doxycycline and streptogramin (p< 0.001). hyl gene positivity (p< 0.001) was found higher in E.faecium isolates whereas esp (p= 0.003) and asa1 (p< 0.001) gene positivity, haemolysin production (p=0.014) and gelatinase activity (p= 0.029) were higher in E.faecalis isolates. AS and ESP were the most frequent virulence factors, with the rates of 26.7% and 25.6%, respectively. There were 32 (35.6%) strains without any of the investigated virulence factors. We have also detected that asa1 gene positive E.faecalis isolates were more resistant to ciprofloxacin (p= 0.001), norfloxacin (p= 0.006) and levofloxacin (p= 0.001) than asa1 gene negative isolates; esp gene positive E.faecalis isolates were more resistant to doxycycline (p= 0.043) than esp gene negative isolates and hyl gene positive E.faecium isolates were more resistant to nitrofurantoine (p= 0.011) than hyl gene negative isolates. This was the first clinical sample originated study, investigating the corelation between antibiotic resistance and virulence factors in urinary Enterococcus isolates in Turkey.
    Mikrobiyoloji bülteni 07/2011; 45(3):430-45. · 0.44 Impact Factor
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    ABSTRACT: An extended-spectrum B-lactamase (ESBL)-producing Providencia stuartii isolate was studied. A qnrA1 gene co-expressing blaVEB-1 gene was detected. Both genes were transferred to the recipient strain. The ciprofloxacin MIC of recipient strain increased tenfold. The blaVEB-1 gene persisted in microorganisms in Turkey but it also spread with PMQR genes to other species. The combination of PMQR with multidrug resistant isolates producing ESBLs may compromise the use of valuable antibiotics. Serious efforts are necessary to detect PMQR determinants not only with common B-lactamases in widespread pathogens but also with uncommon forms that are encountered infrequently.
    The New Microbiologica: official journal of the Italian Society for Medical Virology (SIVIM) 04/2011; 34(2):225-8. · 1.60 Impact Factor
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    ABSTRACT: Objective: Extended spectrum beta-lactamase-producing Klebsiella pneumoniae infections cause difficulties in antibiotic choice for treatment. In this study, the frequency of CTX-M type beta-lactamase, antibiotic resistance rates and co-resistance rates in extended spectrum beta-lactamase (ESBL)-producing K. pneumoniae strains isolated in our hospital were investigated. Material and Methods: A total of 107 K. pneumoniae strains isolated from various clinical specimens in 2007 were included in the study. Antibiotic susceptibility test was performed using disc diffusion method through the recommendations of Clinical Laboratory Standards Institute (CLSI). Double disk synergy test was used for detection of ESBL production. Carbapenemase production was determined with Modified Hodge test. Presence of the gene belonging to CTX-M type beta-lactamases was investigated with polymerase chain reaction method using primers specific to these sites. Results: Frequency of CTX-M type beta-lactamase was detected as 85%. In general, the isolates were found to be highly resistant to co-trimoxasole (SXT) (79%), ampicillin-sulbactam (SAM) (77%), amoxicillin-clavulanic acid (AMC) (68%) and nitrofurantoin (NIT) (52%), and they were found to be less resistant against amikacin (AK) (19%), ciprofloxacin (CIP) (21%), norfloxacin (NOR) (24%), gentamicin (GN) (31%), cefoperazone-sulbactam (SCF) (32%) and piperacillin-tazobactam (TZP) (37%). While the resistance against meropenem (MEM) and fosfomycine (FOS) which are among the most effective antibiotics was determined as 2% and 3% respectively, no resistance was found agaist imipenem. Co-resistance was detected in 90% of the strains and the most common two co-resistance phenotypes were found as AMC/SAM/SXT/NIT (9%) ve AMC/SAM/SXT (6.5%). Conclusion: CTX-M type beta-lactamases were found to be considerably high in K. pneumoniae strains. It was concluded that empirical treatments with these antibiotics could be insufficient in our region since resistance against SXT, SAM, AMC and NIT is high in ESBL producing K. pneumoniae strains.
    Turkiye Klinikleri Journal of Medical Sciences 04/2011; 31(2):300-6. DOI:10.5336/medsci.2010-19642 · 0.10 Impact Factor
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    ABSTRACT: Objective: The nosocomial extended spectrum beta-lactamase (ESBL) producing strains may have high and multiple antibiotic resistance features. This resistance may result in clinical problems especially when choice of appropriate antibiotics is limited in life threatening infections. Current study aims to investigate the antibiotic resistance profiles of imipenem, ciprofloxacin, gentamicin and co-trimoxazole in Escherichia coli strains that isolated in our hospital. Material and Methods: Total 974 E.coli strains that were considered as an infectious agent and isolated from clinical samples of hospitalized patients between 2006 and 2008 in our tertiary health care center was included into study. Antibiotic susceptibility test was performed with disc diffusion method according to provisions of Clinical and Laboratory Standarts Institute (CLSI). Double disc synergy test has been utilized for GSBL production. The E.coli strains that were isolated from different clinical samples of same patient with same susceptibility pattern were not included in to study. Results: Of all strains examined in three-year period, 53.5% and 51.8% were resistant to co-trimoxazole and ciprofloxacin, respectively. ESBL production was detected in 205 (21%) strains. Co-trimoxazole, ciprofloxacin and gentamicin resistance was significantly higher in ESBL producer E.coli strains (p< 0.001). In 2007 and 2008, gentamicin resistance was 27.8% and 35.5% and ESBL production was 18% and 27%, respectively, and this increase was statistically significant. Imipenem resistance was detected in five strains. Multiple drug resistance was detected in 19.2% and co-resistance phenotype in 45.5%. Conclusion: We concluded that in our study imipenem was the most efficient antibiotic and resistance to co-trimoxazole, ciprofloxacin and gentamicin was common especially among ESBL producer E.coli strains. In our region, empirical treatment of infections with these antibiotics might be in sufficient for nosocomial E.coli strains.
    Turkiye Klinikleri Journal of Medical Sciences 02/2011; SCI-expanded(1). DOI:10.5336/medsci.2009-15762 · 0.10 Impact Factor
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    ABSTRACT: In the present study, we investigated the prevalence of CTX-M-type beta-lactamase in extended spectrum beta-lactamase (ESBL)-producing Escherichia coli isolated in our hospital as well as their antibiotic resistance and co-resistance rates. Two hundred nineteen E. coli isolated from clinical specimens between 2006 and 2007 were included. Antibiotic susceptibility test was performed using disc diffusion method and ESBL production was determined using a double-disc synergy test. The presence of CTX-M-type beta-lactamase genes was investigated through amplification using specific primers. The prevalence of CTX-M-type beta-lactamase was found 87% in E. coli isolates. The isolates displayed high rates of resistance to tested antibiotics: 87% to ampicillin-sulbactam (SAM), 77% to amoxicillin-clavulanic acid (AMC), 76% to co-trimoxazole (SXT), 70% to norfloxacin (NOR), 68% to ciprofloxacin (CIP), and 51% to gentamicin (GN). All isolates were found susceptible to imipenem (IPM), meropenem (MEM) and fosfomycin (FOS). Co-resistance was identified in 96% of isolates, and the most common two co-resistance phenotypes were AMC/SAM/GN/NOR/CIP/SXT (12%) and AMC/SAM/NOR/CIP/SXT (11%). CTX-M-type beta-lactamase was present in E. coli isolates at extremely high rates. The empiric therapy with SAM, AMC, SXT, NOR, CIP, and GN may not be adequately effective against certain isolates of E. coli due to high rate of resistance.
    African journal of microbiology research 02/2011; 5(1):44-49. · 0.54 Impact Factor
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    ABSTRACT: This study evaluated the presence of carbapenem hydrolysing b-lactamase genes and plasmid-mediated quinolone resistance (PMQR) determinants in 22 Klebsiella pneumoniae isolates collected from the Istanbul Medical Faculty, Turkey, which reduced the susceptibility or resistance to carbapenem. The VITEK ® 2 system and E-tests were used to determine the minimum inhibitory concentrations needed to inhibit bacterial growth. Genes were screened by polymerase chain reaction, and gene transferability was evaluated by transconjugation. Strain clonality was investigated by pulsed-field gel electrophoresis (PFGE). All strains were OXA-48 b-lactamase producers and three (13.6%) were also positive for the aac(6')-Ib-cr gene. Most of the strains harboured other b-lactamase (bla) genes such as bla TEM , bla SHV , bla CTX-M and bla VEB-1 . The transconjugants mostly harboured bla OXA-48 and other b-lactamases separately. PFGE revealed eight pulsotypes among the isolates. The coexistence of bla OXA-48 and PMQR in K. pneumoniae isolates may present a significant threat to health, especially in the nosocomial setting.
    The Journal of international medical research 01/2011; 39:1932-1940. · 1.10 Impact Factor
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    H Nazik, M Ilktaç, B Ongen
    Journal of chemotherapy (Florence, Italy) 05/2009; 21(2):219-21. · 1.07 Impact Factor
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    Ongen B, Nazik H
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    ABSTRACT: In this study, we investigated the presence of qnrA, qnrB and qnrS among Campylobacter isolates more than 50% of which were resistant to ciprofloxacin and ofloxacin. The antimicrobial susceptibility testing was carried out by disc diffusion method. QnrA, qnrB and qnrS genes were investigated by using PCR with specific primers in consecutive 61 clinical Campylobacter strains isolated in the Istanbul Medical Faculty. The Campylobacter isolation rate was 1.74%. 60.6% were resistant to ciprofloxacin and 52.4% to ofloxacin. Additionally none were resistant to erythromycin and clarithromycin. The plasmid-mediated quinolone resistance genes were absent in 61 Campylobacter strains.

Publication Stats

66 Citations
19.95 Total Impact Points

Institutions

  • 2004–2014
    • Istanbul University
      • • Department of Medical Microbiology
      • • Department of Microbiology and Clinical Microbiology
      İstanbul, Istanbul, Turkey
  • 2012
    • Gulhane Military Medical Academy
      • Department of Gastroenterology
      Engüri, Ankara, Turkey
  • 2011
    • İstanbul Eğitim ve Araştırma Hastanesi
      Cebelibereket, Osmaniye, Turkey
    • Istanbul Training and Research Hospital
      İstanbul, Istanbul, Turkey