Publications by authors named "Gokhan Aygun"

26 Publications

  • Page 1 of 1

Clinical and microbiological characteristics of Aeromonas bacteremia in Turkey.

Acta Microbiol Immunol Hung 2021 Jun 16. Epub 2021 Jun 16.

5Department of Infectious Disease, Medical School of Cerrahpasa, Istanbul University, İstanbul, Turkey.

We investigated the cases with Aeromonas bacteremia in terms of clinical and microbiological characteristics, underlying disease and mortality rates. Patients with positive blood cultures were included in this research. Aeromonas bacteremia was diagnosed as at least one positive blood culture for Aeromonas species. The bacteremia was defined as community origin if the onset was in the community or within 72 hours of hospital admission. The others were considered as nosocomial. All bacteria were defined as Aeromonas with conventional method. Species identification was verified by VITEK system. Antibiotic susceptibility tests were analyzed with the disc diffusion, E-test method or VITEK system. Thirty-three patients were diagnosed with bacteremia due to Aeromonas spp. Hematologic and solid tumors were the leading underlying conditions, followed by cirrhosis. Two patients (6%) had community-acquired infections. Aeromonas hydrophila was the most common isolated bacterium. The crude mortality rate was 36%. 12 patients died and 6 deaths and 4 deaths were detected in patients with bacteremia caused by A. hydrophila and Aeromonas sobria respectively. All strains were resistant to ampicillin and more than 90% of the strains were susceptible to trimethoprim-sulfamethoxazole, fluoroquinolone, third generation cephalosporins, and carbapenems. Aeromonas sp. is not a frequent cause of bacteremia however, it may lead to high mortality rates, especially in the immunocompromised hosts and patients with liver cirrhosis. Nosocomial Aeromonas bacteremia is not uncommon in these populations. Broad-spectrum cephalosporins, piperacillin-tazobactam, fluoroquinolones, and carbapenems remain as effective antimicrobial agents for therapy of Aeromonas bacteremia.
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http://dx.doi.org/10.1556/030.2021.01449DOI Listing
June 2021

Tocilizumab in COVID-19: The Cerrahpaşa-PREDICT score.

J Infect Chemother 2021 May 12. Epub 2021 May 12.

Department of Infectious Diseases and Clinical Microbiology, Cerrahpaşa Faculty of Medicine, Istanbul University-Cerrahpaşa, Istanbul, Turkey.

Background: Cytokine release syndrome (CRS), characterized by overproduction of proinflammatory cytokines in the course of severe coronavirus disease 2019 (COVID-19), has been suggested as the major cause of mortality. Tocilizumab, a recombinant humanized monoclonal antibody against human IL-6 receptor, poses a therapeutic option for the treatment of CRS leading to severe acute respiratory syndrome in coronavirus-2 (SARS-CoV-2) infection.

Methods: We performed a single-center retrospective study to reveal the outcome of COVID-19 patients on tocilizumab and proposed "the Cerrahpaşa-PREDICT score", a new clinical scoring system using clinical and laboratory parameters that would help predicting the 28-day mortality of COVID-19 patients receiving tocilizumab.

Results: Eighty-seven patients (median age: 59 years) were included of whom 75.8% were male. Tocilizumab use significantly improved clinical and laboratory parameters. The 28-day mortality rate on tocilizumab was 16.1%. The Cerrahpaşa-PREDICT score, consisting of platelet counts, procalcitonin, D-dimer levels, SOR and the time from symptom onset to tocilizumab administration had a positive predictive value of 94.5% and negative predictive value of 92.9% for anticipating 28-day mortality.

Conclusions: Severe COVID-19 should closely be monitored for the signs of hyperinflammation. We showed that administration of tocilizumab early in the course of the disease (prior to ICU admission) resulted in a favorable outcome. Close monitoring usually aids identifying patients who would benefit from tocilizumab. In this regard, the Cerrahpaşa-PREDICT score might serve as a practical tool for estimating the 28-day mortality in COVID-19 patients who received tocilizumab and would facilitate timely recognition of fatal cases to be evaluated for other therapeutic options.
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http://dx.doi.org/10.1016/j.jiac.2021.05.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8114762PMC
May 2021

Colistin resistance increases 28-day mortality in bloodstream infections due to carbapenem-resistant Klebsiella pneumoniae.

Eur J Clin Microbiol Infect Dis 2021 May 8. Epub 2021 May 8.

Istanbul Universitesi-Cerrahpasa, Cerrahpasa Faculty of Medicine, Cerrahpasa Tip Fakultesi, İstanbul, Turkey.

Mortality due to K. pneumoniae bacteremia is on rise, particularly in regions with high rates of carbapenem and colistin resistance. We aimed to define risk factors for colistin resistance and its impact on mortality. Patients diagnosed with "carbapenem-resistant K. pneumoniae (CRKp)" bacteremia between 2014 and 2018 were divided into two groups as "colistin susceptible (ColS)" and "colistin resistant (ColR)" based on broth microdilution method. Retrospective case-control study was conducted to compare characteristics and outcomes. Multiple logistic regression model was used to define independent risk factors for acquired colistin resistance and Cox proportional hazard model for 28-day mortality. A total of 82 patients (39 ColS and 43 ColR) were included. Mean age was 61.5 years, and 50 (61%) were male. Colistin resistance was significantly increased with duration of hospital stay (p = 0.007) and prior colistin use (p = 0.007). Overall, the 28-day mortality rate was 66%. Age (p = 0.014) and colistin resistance significantly increased 28-day (p = 0.009) mortality. Microbiological response to treatment within 7 days favors survival. PFGE analysis revealed an outbreak with K. pneumoniae ST78 and ST45 clones. Patients treated with combined antimicrobials had significantly lower 28-day mortality (p = 0.045) in comparison to monotherapy. However, types of combinations did not show significant superiority on each other. Colistin resistance increases 28-day mortality in CRKp bacteremia. Although combined regimens are more effective than monotherapy, existing antibacterial combinations have no apparent superiority to each other. New treatment options are pivotal.
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http://dx.doi.org/10.1007/s10096-020-04124-yDOI Listing
May 2021

Effects of calcineurin inhibitors, cyclosporine A and tacrolimus (FK506), on the activity of antifungal drugs against spp.

J Med Microbiol 2021 Apr;70(4)

Department of Medical Microbiology, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey.

The simultaneous use of antifungals with immunosuppressive agents has become a necessity for patients taking immunosuppressive therapy. However, antifungal drugs are problematic because of their limited target. Scientists have been searching for new antifungals and some compounds with at least additive effects on antifungals. Calcineurin inhibitors used as immunosuppressive agents also attract attention due to their antifungal property. To evaluate the activity of two calcineurin inhibitors alone and in combination with amphotericin B (AMB), caspofungin (CAS), itraconazole (ITR), voriconazole (VOR) and fluconazole (FLU). MICs of AMB, CAS, ITR, VOR, FLU and cyclosporine A (CsA) and tacrolimus (TAC) as calcineurin inhibitors were evaluated by the broth microdilution method against (=13), (=7) and (=10). Checkerboard and time-kill methods were performed to investigate the activity of combining calcineurin inhibitors with antifungal drugs. The lowest MIC values were detected with VOR for all isolates tested. Although we did not detect any inhibition for CsA or TAC alone at concentrations tested in this study, the combinations of CAS with CsA showed the highest synergistic activity (36.7%) by the checkerboard method, and CAS with CsA and ITR with TAC combinations exhibited apparent synergistic interaction by the time-kill method. However, the combinations of both CsA and TAC with AMB resulted in antagonistic interactions, especially against isolate in time-kill testing. Synergistic interactions in the combinations of TAC or CsA with antifungal drugs, except for AMB, in many concentrations was found to be promising in terms of the treatment of patients with fungal infections.
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http://dx.doi.org/10.1099/jmm.0.001354DOI Listing
April 2021

[Evaluation of the Diagnostic Performance of Different Principles of SARS-CoV-2 Commercial Antibody Tests in COVID-19 Patients].

Mikrobiyol Bul 2021 Apr;55(2):207-222

Istanbul University-Cerrahpasa, Cerrahpaşa Faculty of Medicine, Department of Medical Microbiology, Istanbul, Turkey.

Following the emergence of severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) and using only PCR for diagnosis, antibody tests have been rapidly developed by various commercial companies. There are differences between the sensitivity and specificity of these tests due to the usage of different viral target proteins and antibody subclasses. In order to evaluate the diagnostic use of these tests, we aimed to examine the diagnostic performance, especially sensitivity and specificity, of SARS-CoV-2 IgM, IgA and IgG tests of various companies (Abbott, Roche, Euroimmun, Dia.Pro, Anshlabs, Vircell, UnScience and RedCell), which have different principles (ECLIA/CLIA, EIA, LFA). Current (n= 180) and past (n= 180) COVID-19 patients with clinical and molecular diagnosis of COVID-19 admitted to Istanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine Hospital, Pandemic Polyclinic with suspected COVID-19 infection, were included in our study. The patients admitted within the first 3 weeks after the onset of symptoms were included in the current patient group, and those admitted at the third and after the third week were included in the past patient group. Serum samples (n= 180) obtained from Istanbul Sisli Hamidiye Etfal Training and Research Hospital, Blood Center between April and June 2018 before the COVID-19 pandemic were included in the study as a control group. All the tests included in our study were studied with the recommendations of the manufacturer companies. Between the IgG detection tests with different principles in patients with past COVID-19, the sensitivity and specificity values of the most effective tests were; 86.7%/99.4% (Abbott), 86.1%/98.9% (Dia.Pro), 91.3%/95% (RedCell). Between the IgM detection tests with different principles in current COVID-19 patients, the sensitivity and specificity values were; 67.8%/99.4% (Abbott), 68.9%/98.6% (Vircell), 50%/97.5% (RedCell). Abbott IgM with a kappa coefficient of 0.67 and Vircell IgM + IgA test with a kappa coefficient of 0.65 showed the best fit in patients with current COVID-19 infection. In patients with past COVID-19, Abbott IgG with 0.86 kappa coefficient and Dia.Pro IgG test with 0.85 kappa coefficient showed the best match. Due to the low sensitivity of IgM detection antibody tests, they should not be preferred instead of real-time reverse transcriptase polymerase chain reaction in routine diagnosis. IgG detection tests may be preferred to detect the antibody response and the titers in people who have had COVID-19 for population seroprevalence and especially therapeutic immune plasma production. However, it is thought that the combined use of both ECLIA/CLIA-based and EIA/ELISA-based tests together may be more effective in routine use for SARS-CoV-2 IgG tests.
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http://dx.doi.org/10.5578/mb.20219907DOI Listing
April 2021

Untreated herpes simplex virus encephalitis without a fatal outcome.

J Neurovirol 2021 Mar 31. Epub 2021 Mar 31.

Department of Medical Microbiology, Medical School of Cerrahpasa, Istanbul University, Istanbul, Turkey.

Herpes simplex virus encephalitis (HSE) is the most common sporadic fatal encephalitis. Although timely administered acyclovir treatment decreases mortality, neuropsychiatric sequelae is still common among survivors. Magnetic resonance imaging is frequently utilized for the diagnosis of HSE, which typically involves temporal lobe(s) and can be mixed with brain tumors involving the same area. Here, we report a case of HSE, who received acyclovir with a delay of 90 days because of presumptive tumor diagnosis and survived with minimal sequelae.
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http://dx.doi.org/10.1007/s13365-021-00968-yDOI Listing
March 2021

Candida auris Fungemia and a local spread taken under control with infection control measures: First report from Turkey.

Indian J Med Microbiol 2021 Apr 27;39(2):228-230. Epub 2021 Mar 27.

Istanbul University-Cerrahpasa, Cerrahpasa School of Medicine, Department of Medical Microbiology, Istanbul, Turkey. Electronic address:

Candidaauris, draws attention as a new emerging antifungal resistant pathogen, leading to healthcare-associated infections and outbreaks. This is the first report of C. auris fungemia in a 81-year-old patient, confirmed by sequential analysis, from Turkey. Although the source of the isolate could not be identified, its spread in the hospital has been taken under control by effective infection control measures.
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http://dx.doi.org/10.1016/j.ijmmb.2021.03.007DOI Listing
April 2021

The role of typical and atypical pathogens in acute exacerbations of chronic obstructive pulmonary disease.

Clin Respir J 2021 Feb 24;15(2):209-215. Epub 2020 Oct 24.

Department of Pulmonary Diseases, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey.

Objectives: The exact role of Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila in the development of chronic obstructive pulmonary disease exacerbations remains to be elucidated. This study was conducted to identify nonspecific and atypical pathogens associated with acute exacerbations of COPD.

Materials And Methods: Between February 2013 and February 2015, 107 patients were analyzed. Sixty-nine comprised the inpatient and 38 comprised the outpatient treatment group.

Results: When nonspecific culture results were taken into consideration only a causative organism could be detected in 46.7% of the patients. The detection rate increased to 85.1% with the additional use of polymerase chain reaction (PCR), direct fluorescent antibody (DFA) test, and culture methods. More than one causative agent was responsible for COPD exacerbation in 53.3% of patients: two agents in 37.3%, three agents in 15%, and four agents in 0.9%. H. influenzae was detected in 63 (58.9%) patients, S. pneumoniae in 57 (53.2%), P. aeruginosa in 15 (14.0%), and L. pneumophila in 11 (10%). L. pneumophila was the more commonly isolated agent in the inpatient group (P = 0.002). Patients receiving continuous oxygen therapy and noninvasive mechanical ventilation were more likely to have an exacerbation associated with P. aeruginosa (P = 0.008 and P = 0.009, respectively).

Conclusion: The additional use of DFA for Legionella and multiplex PCR in combination with nonspecific microbiological culturing methods greatly improves the ability to identify infectious agents in acute exacerbations of COPD. There should be a high index of suspicion for P.aeruginosa as a causative organism, particularly in subjects receiving continuous oxygen therapy and/or using NIV and L. pneumophila should certainly be taken into consideration in severe COPD exacerbations.
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http://dx.doi.org/10.1111/crj.13286DOI Listing
February 2021

Change in species distribution and antifungal susceptibility of candidemias in an intensive care unit of a university hospital (10-year experience).

Eur J Clin Microbiol Infect Dis 2021 Feb 15;40(2):325-333. Epub 2020 Sep 15.

Department of Infectious Diseases and Clinical Microbiology, Medical Faculty, Istanbul Medipol University, Istanbul, Turkey.

Candidemia is a nosocomial infection mostly found in critically ill patients. Our objectives were to evaluate the change in distribution and resistance profile of Candida spp. isolated from candidemic patients in our intensive care unit over two 5-year periods spanning 15 years and to evaluate the risk factors. Records from the microbiology laboratory were obtained, from January 2004 to December 2008 and from January 2013 to December 2017, retrospectively. Antifungal susceptibility was performed by E-test and evaluated according to EUCAST breakpoints. A total of 210 candidemia cases occurred; 238 Candida spp. were isolated in 197 patients (58.8% male; mean age, 59.2 ± 19.6 years). The most predominant risk factor was central venous catheter use. Species distribution rates were 32%, 28%, 17%, and 11% for C. albicans (n = 76), C. parapsilosis (n = 67), C. glabrata (n = 40), and C. tropicalis (n = 27), respectively. Resistance rate to anidulafungin was high in C. parapsilosis over both periods and increased to 73% in the second period. Fluconazole showed a remarkable decrease for susceptibility in C. parapsilosis (94 to 49%). The prevalence of MDR C. parapsilosis (6%/33%) and C. glabrata (0%/44%) increased in the second period. We observed a predominance of non-albicans Candida spp., with C. parapsilosis being the most frequent and C. glabrata infections presenting with the highest mortality. High level of echinocandin resistance in C. parapsilosis and increasing prevalences of MDR C. parapsilosis and C. glabrata seem emerging challenges in our institution.
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http://dx.doi.org/10.1007/s10096-020-03994-6DOI Listing
February 2021

Risk factors for development of vancomycin-resistant enterococcal bacteremia among VRE colonizers : A retrospective case control study.

Wien Klin Wochenschr 2021 May 10;133(9-10):478-483. Epub 2020 Sep 10.

Department of Infectious Disease, Medical School of Cerrahpasa, Istanbul University, Istanbul, Turkey.

Aims: We aimed to determine the proportion of vancomycin-resistant enterococci (VRE) colonized patients among all inpatients who later developed VRE bacteremia during hospital stay and to identify the risk factors for VRE bacteremia at a tertiary hospital.

Material And Methods: Patients with positive rectal screening or any clinically significant positive culture results for VRE were included in 1‑year follow-up. Colonization with VRE was defined as a positive culture (rectal, stool, urinary) for VRE without infection and VRE bacteremia was defined as positive blood culture if the signs and symptoms were compatible with infection. To determine the risk factors for VRE bacteremia among VRE colonized patients, a retrospective case control study was performed. The two groups were compared in terms of variables previously defined as risk factors in the literature.

Results: Of 947 positive samples, 17 VRE bacteremia were included in the analysis. Cephalosporin use for more than 3 days within 3 months was a significant risk factor for bacteremia (p = 0.008). Prior use of carbapenems was found to be statistically significant for bacteremia (p = 0.007). In multivariate analyses the use of carbapenems and cephalosporins was an independent risk factor for developing bacteremia among VRE colonizers (odds ratio, OR, 6.67; 95% confidence interval, CI, 1.30-34; p = 0.022 and OR 4.32, 95% CI 1.23-15; p = 0.022, respectively).

Conclusion: A VRE colonization in patients receiving broad-spectrum beta-lactam antibiotics including carbapenems and cephalosporins may result in bacteremia. It is possible to keep mortality at very low levels in VRE bacteremia with effective infection control measures, rapid infectious diseases consultation and rational antimicrobial treatment based on current epidemiological data.
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http://dx.doi.org/10.1007/s00508-020-01733-7DOI Listing
May 2021

Thyroid abscess due to Eikenella corrodens in a pediatric patient.

J Infect Dev Ctries 2019 10 31;13(10):945-947. Epub 2019 Oct 31.

Department of Pediatric Infectious Disease, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.

Eikenella corrodens is one of the HACEK bacteria that is commensal microorganism of the oropharngeal flora. E. corrodens has been increasingly reported to cause pyogenic abscesses, especially in diabetic or immunocompromised adults. It is less frequently reported in immunocompotent children. Here, we report a deep neck infection, including the thyroid gland, in a previously healthy girl. E. corrodens was the only microorganism isolated in two different cultures. Antibiotic susceptibility is variable, in contrast to other oropharyngeal pathogens. Thus, to avoid delayed treatment, E. corrodens should always be considered in infections of the head and neck area.
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http://dx.doi.org/10.3855/jidc.11057DOI Listing
October 2019

Usage of a Bundle Application Process in Decreasing Ventriculoperitoneal Shunt Infections.

Turk Neurosurg 2020 ;30(4):550-556

Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Infection Control Comittee, Istanbul, Turkey.

Aim: To determine the effect of using three concurrent measures (2% chlorhexidine gluconate +70% alcohol for skin cleaning, changing the dressing every 48 hours, and observing the operating room) for patients who had venriculoperitoneal shunt (VPS) implantations on the infection rate.

Material And Methods: This was a prospective interventional study. Using infection prevention compliance control lists, patients who had a VPS implanted between November 2012 and November 2013 were compared to those who had a VPS implanted between October 2011 and October 2012. The data included information about the patients, follow-up, and infection prevention. These data were obtained for the pre-, peri-, and postoperative periods.

Results: Triple bundle prevention in the applied protocol significantly reduced the VPS infection rate in the study group compared to the control group (p < 0.005).

Conclusion: These findings revealed the importance of creating a prevention protocol and following it regularly in a way for all surgery, operating room, and service teams fully comply to prevent VPS infections.
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http://dx.doi.org/10.5137/1019-5149.JTN.26864-19.3DOI Listing
November 2020

In Vitro Antifungal Effect of Acrylic Corneal Glue (N-Butyl-2-Cyanoacrylate).

Cornea 2019 Dec;38(12):1563-1567

Department of Ophthalmology, Cerrahpasa School of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey.

Purpose: The purpose of this study was to evaluate the in vitro antifungal effects of n-butyl-2-cyanoacrylate (nB2CA; Histoacryl Blue; B. Braun, Melsungen, Germany) against a variety of different fungal species.

Methods: Inocula taken from suspensions prepared with Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus ochraceus, Aspergillus oryzae, Fusarium solanii, Fusarium oxysporum, Trichoderma spp., Rhizomucor spp., Scedosporium apiospermum, Penicillium commune, Phoma glomerata, and Chrysosporium spp. molds and Candida albicans, Candida glabrata, Candida parapsilosis, Candida kruzei, Candida dubliniensis, Candida tropicalis, Candida kefyr, and Trichosporon asahii yeasts were spread on the surface of RPMI1640 agar media. Then, 50 μL of nB2CA was dropped on the surface of these media and they were incubated at 35°C. Observation of a clear zone of inhibition around the nB2CA was regarded as an indicator of the susceptibility of the fungi to nB2CA, and the absence of this zone was interpreted as an indicator of nonsusceptibility. The inhibition zone diameter was measured across the largest clear zone.

Results: A zone of inhibition was observed around nB2CA for all of the yeast and mold species except A. flavus, A. oryzae, and Chrysosporium spp. Among molds, the largest zone of inhibition was observed with P. glomerata (25.7 ± 0.6 mm), whereas among yeasts, the largest zone of inhibition was observed with C. kruzei (19.3 ± 1.5 mm).

Conclusions: nB2CA has shown antifungal activity against 18 different mold and yeast species, but not against A. flavus, A. oryzae, and Chrysosporium spp. molds.
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http://dx.doi.org/10.1097/ICO.0000000000002061DOI Listing
December 2019

Molecular Mechanisms of Colistin Resistance Among Klebsiella Pneumoniae Strains.

Clin Lab 2019 Jul;65(7)

Background: The increasing rate of infections caused by multiple drug resistant gram-negative bacteria has led to resuscitation of colistin. As a result, colistin resistance, mainly among Klebsiella pneumoniae strains has also been increased. The aim of this study was to investigate molecular mechanisms behind colistin resistance.

Methods: Twenty colistin-resistant K. pneumoniae strains isolated from clinical samples of different patients were involved in this study. VITEK2 automated ID/AST system (Biomeriux, France) was used for the identification and also the susceptibility testing for antibiotics other than colistin. Colistin susceptibility was determined by broth microdilution method. To identify the mechanisms of resistance, mutations on mgrB genes, expression levels of pmrA, pmrB, pmrC, pmrD, pmrE, pmrK, phoQ, and phoP genes, and the presence of plasmid mediated colistin resistance genes, mcr-1 and mcr-2 were investigated.

Results: As a result of the study, increased expression levels of the pmrA, pmrB, pmrD, pmrK, phoP, and phoQ genes were observed. All colistin resistant strains were found wild type for the mgrB gene which is thought to be esponsible for colistin resistance. Also, no mcr-1 or mcr-2 genes which are the causes of plasmid mediated colistin resistance have been detected in any of the strains.

Conclusions: Among the colistin resistant K. pneumoniae strains included in our study, increased expression Levels of the genes responsible for cell membrane modifications related with colistin resistance were the most common mechanisms.
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http://dx.doi.org/10.7754/Clin.Lab.2019.180705DOI Listing
July 2019

Determination of clinical significance of coagulase-negative staphylococci in blood cultures.

Diagn Microbiol Infect Dis 2017 Mar 14;87(3):291-294. Epub 2016 Dec 14.

Cerrahpasa Medical School of Istanbul University, Medical Microbiology, Istanbul, Turkey. Electronic address:

The aim of this study was to investigate the criteria used to distinguish coagulase-negative staphylococci (CoNS) bacteremia from contamination. We evaluated 162 adult patients with CoNS-positive blood cultures (BCs). Of the 162 patients, 35 (21.6%) had at least 2 positive BCs and 127 (78.4%) had a single positive BC. According to the Laboratory-Confirmed Bloodstream Infection (LCBI) criteria, 24 (14.8%) patients with the same species of CoNS had true bacteremia, and 138 (85.2%) patients had contaminants. Despite the detection of the same CoNS species, 9 of the 24 patients had different CoNS genotypes. Using clinical assessments, only 20 patients were diagnosed with true bacteremia, 8 of them had a single positive BC. We concluded that only using the LCBI criteria or clinical evaluations of a patient were not sufficient to distinguish CoNS bacteremia from contamination. Molecular identification should also be performed as a diagnostic laboratory parameter for CoNS bacteremia.
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http://dx.doi.org/10.1016/j.diagmicrobio.2016.12.006DOI Listing
March 2017

Investigation of carbapenem resistance and the first identification of Klebsiella pneumoniae carbapenemase (KPC) enzyme among Escherichia coli isolates in Turkey: A prospective study.

Travel Med Infect Dis 2016 Nov - Dec;14(6):572-576. Epub 2016 Nov 23.

Cerrahpasa Medical School of Istanbul University, Department of Medical Microbiology, Istanbul, Turkey. Electronic address:

Background: The aim of this study was to determine the presence of carbapenem resistance and carbapenemase production in Escherichia coli isolates from clinical samples in Turkey.

Methods: The prospective study included a total of 4.052 Escherichia coli isolates collected from patients admitted to a hospital from March 2011 to May 2012. We used ertapenem disc for screening carbapenemase production, and the confirmation was performed by using Etest. The resistance mechanisms and genetic relatedness of the carbapenem resistant strains were investigated by using PCR (polymerase chain reaction) and pulsed-field gel electrophoresis (PFGE), respectively.

Results: Among the 4.052 E. coli isolates, 24 (0.59%) were found to be carbapenem resistant. Of these, only 5 isolates were positive for OXA-48 and 2 isolates were positive for Klebsiella pneumoniae carbapenemase (KPC)-2. The KPC-2 producing E. coli strains (n = 2) were both isolated from the same patient. The bla genes were confirmed using DNA sequence analysis. The genetic relationship between the 24 E. coli strains studied by PFGE revealed that the strains were genetically unrelated.

Conclusions: This article confirms, to our knowledge for the first time, the detection of KPC-2-producing E. coli in Turkey, with OXA-48 being the most frequent carbapenemase in the study.
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http://dx.doi.org/10.1016/j.tmaid.2016.11.006DOI Listing
May 2017

Bacterial colonization and associated factors in patients with bronchiectasis.

Ann Thorac Med 2016 Jan-Mar;11(1):55-9

Department of Pulmonary Diseases, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.

Objectives: To evaluate the bacterial colonization and associated risk factors in patients with bronchiectasis.

Methods: A total of 121 patients followed at the Bronchiectasis Unit, between 1996 and 2013 and diagnosed as having noncystic fibrosis bronchiectasis with high resolution computed tomography or multi-slice computed tomography were included in this retrospective study. The following definition of colonization was used for study purposes: Detection of at least two isolates of an organism separated by at least 3 months in a year.

Results: Of these 121 patients, 65 (54%) were female and 56 (46%) were male. Mean age was 50.6 ± 16.1 years. Mean duration of illness was 20.3 ± 15.5 years. 43 (35.5%) cases had colonization. The major pathogens responsible for colonization were Pseudomonas aeruginosa (n = 25; 20.6%) and Haemophilus influenzae (n = 14, 11.5%). The stepwise logistic regression analysis showed a significant association between colonization and a low percentage of forced vital capacity (FVC%) and the presence of cystic bronchiectasis (P < 0.05).

Conclusion: The following factors have been found to be associated with colonization in patients with bronchiectasis: Low FVC% and the presence of cystic bronchiectasis.
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http://dx.doi.org/10.4103/1817-1737.172297DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748616PMC
March 2016

Blood stream infections due to OXA-48-like carbapenemase-producing Enterobacteriaceae: treatment and survival.

Int J Infect Dis 2014 Sep 3;26:51-6. Epub 2014 Jul 3.

Department of Infectious Diseases, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul 34098, Turkey.

Background: Blood stream infections (BSIs) due to carbapenem-resistant Enterobacteriaceae (CRE) are associated with high hospital mortality rates and present a tremendous challenge to clinicians. The optimal treatment remains undefined. We aimed to investigate the risk factors for mortality and the correlation between different treatment modalities and outcomes.

Methods: The clinical characteristics and treatment outcomes of a cohort of 36 patients with BSIs due to CRE were investigated and a retrospective nested case-control study of surviving and non-surviving patients was conducted.

Results: Fifty percent of the cases were male and the mean patient age was 54.9 ± 15.8 years. Klebsiella pneumoniae was the etiological agent in 26 cases (72.2%), Escherichia coli in eight (22.2%), and Enterobacter aerogenes in two (5.5%). All strains were phenotypically positive for carbapenemase activity and all except two (one E. coli and one K. pneumoniae) yielded both blaOXA-48 carbapenemases and blaCTX-M-type extended-spectrum beta-lactamases (ESBLs) in PCR products. The 14-day, 28-day, and all-cause in-hospital mortality rates were 41.6%, 50%, and 58.3%, respectively. The median time to death was 8 days (range 2-52 days). No significant differences were observed between survivors and non-survivors in terms of baseline characteristics, comorbid conditions, etiologies, or sources of bacteremia, however hematological malignancies (p=0.015) and prolonged neutropenia (p=0.044) were more common in non-survivors. Microbiological eradication and clinical response within 7 days were two major determinants of 28-day attributable mortality (p=0.001 and p=0.001, adjusted r(2)=0.845). Colistin-based dual combinations, and preferably triple combinations, were associated with significantly better outcomes when compared to non-colistin-based regimens (p<0.001). Time to active treatment had a significant effect on the course of infection (p=0.014).

Conclusion: Earlier active treatment with colistin based regimens and microbiological and clinical response within 7 days are major predictors of survival in cases of BSIs due to CRE. Rectal screening offers the advantage of earlier recognition and prompt empirical treatment.
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http://dx.doi.org/10.1016/j.ijid.2014.05.012DOI Listing
September 2014

First imported coccidioidomycosis in Turkey: A potential health risk for laboratory workers outside endemic areas.

Med Mycol Case Rep 2014 Jan 20;3:20-5. Epub 2014 Jan 20.

Department of Dermatology, Samatya Training and Research Hospital, Istanbul 34098, Turkey.

Coccidioidomycosis caused by Coccidioides immitis or Coccidioides posadasii is endemic in arid climate zones in America, travel-related cases have been reported. We report the first documented case of coccidioidomycosis in Turkey, overviewing reported cases in Europe and underlying difficulties of differential diagnosis outside endemic regions. The patient was an otherwise healthy 41-year-old man who travelled endemic areas. Laboratory diagnosis was based on direct microscopy of two subsequent subcutaneous biopsy specimens and culture and confirmed molecularly. Laboratory personnel should become aware that BioSafety Level-3 organisms may become more frequent and widespread.
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http://dx.doi.org/10.1016/j.mmcr.2014.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3930961PMC
January 2014

Bacteriological evaluation of tonsillar microbial flora according to age and tonsillar size in recurrent tonsillitis.

Eur Arch Otorhinolaryngol 2014 Jun 1;271(6):1661-5. Epub 2014 Feb 1.

Department of Otorhinolaryngology, Taksim Training and Research Hospital, Tarabya cad Adalet Sitesi B5, D11, Tarabya, Sariyer, Istanbul, 34457, Turkey,

Although numerous studies based on the bacteriology of the tonsil have been carried out, none of them analyzed the variation of tonsillar flora with respect to both age and tonsillar size. The purpose of this study was to isolate the facultative and obligate anaerobes both from the surface and the core of tonsils in recurrent tonsillitis as well as to analyze the variation of isolated bacterial strains according to age and tonsillar size. A prospective study was performed on 111 patients who underwent tonsillectomy. We analyzed the differences between the bacterial pathogens in recurrent tonsillitis and semi-growth estimates with regard to age and tonsillar grade. Among 111 cases, 604 bacterial strains of 21 different from the tonsil superficial and core were isolated. The most common facultative anaerobic species isolated from the surface and core were Coagulase-negative staphylococci, Alpha-hemolytic streptococci and Diphtheroid bacilli in all subgroups except patients below 8 years old. The most commonly obligate anaerobic species isolated from the core were Propionibacterium acnes, Prevotella melaninogenica and Peptostreptococcus anaerobius. We found no significant difference in the cultured bacteria with respect to age and tonsillar size. The study subgroups did not differ in the occurrence of semiquantitative growth estimates of 3-4+. Our study demonstrates that there is polymicrobial aerobic and anaerobic flora in tonsils with regardless of patient's age and tonsillar size. This polymicrobial spectrum of bacteria may contribute to recurrence and to the failure of conservative treatment of these cases and therefore leads to surgical therapy.
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http://dx.doi.org/10.1007/s00405-014-2898-5DOI Listing
June 2014

A fatal case of urosepsis due to Corynebacterium riegelii.

Braz J Microbiol 2013 30;44(2):475-6. Epub 2013 Oct 30.

Istanbul University, Cerrahpasa Medical Faculty, Microbiology and Clinical Microbiology Department, Istanbul, Turkey.

Corynebacterium species other than Corynebacterium diphtheriae rarely cause infections in human but rather reside in flora, however they have been reported to cause opportunistic infections in both immunocompromised and immunecompetent patients. Here we report for the first time a case of an elderly female patient presenting with a fatal urosepsis caused by a recently defined pathogen, Corynebacterium riegelii, identified on second day after patient hospitalization leading to a progressive worsening and death of the patient on 6th day.
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http://dx.doi.org/10.1590/S1517-83822013000200022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3833147PMC
January 2015

Impact of a multidimensional infection control approach on central line-associated bloodstream infections rates in adult intensive care units of 8 cities of Turkey: findings of the International Nosocomial Infection Control Consortium (INICC).

Ann Clin Microbiol Antimicrob 2013 May 4;12:10. Epub 2013 May 4.

Ondokuz Mayis University Medical School, Samsun, Turkey.

Background: Central line-associated bloodstream infections (CLABs) have long been associated with excess lengths of stay, increased hospital costs and mortality attributable to them. Different studies from developed countries have shown that practice bundles reduce the incidence of CLAB in intensive care units. However, the impact of the bundle strategy has not been systematically analyzed in the adult intensive care unit (ICU) setting in developing countries, such as Turkey. The aim of this study is to analyze the impact of the International Nosocomial Infection Control Consortium (INICC) multidimensional infection control approach to reduce the rates of CLAB in 13 ICUs of 13 INICC member hospitals from 8 cities of Turkey.

Methods: We conducted active, prospective surveillance before-after study to determine CLAB rates in a cohort of 4,017 adults hospitalized in ICUs. We applied the definitions of the CDC/NHSN and INICC surveillance methods. The study was divided into baseline and intervention periods. During baseline, active outcome surveillance of CLAB rates was performed. During intervention, the INICC multidimensional approach for CLAB reduction was implemented and included the following measures: 1- bundle of infection control interventions, 2- education, 3- outcome surveillance, 4- process surveillance, 5- feedback of CLAB rates, and 6- performance feedback on infection control practices. CLAB rates obtained in baseline were compared with CLAB rates obtained during intervention.

Results: During baseline, 3,129 central line (CL) days were recorded, and during intervention, we recorded 23,463 CL-days. We used random effects Poisson regression to account for clustering of CLAB rates within hospital across time periods. The baseline CLAB rate was 22.7 per 1000 CL days, which was decreased during the intervention period to 12.0 CLABs per 1000 CL days (IRR 0.613; 95% CI 0.43 - 0.87; P 0.007). This amounted to a 39% reduction in the incidence rate of CLAB.

Conclusions: The implementation of multidimensional infection control approach was associated with a significant reduction in the CLAB rates in adult ICUs of Turkey, and thus should be widely implemented.
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http://dx.doi.org/10.1186/1476-0711-12-10DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3674978PMC
May 2013

Prospective observational study on antibiotic-associated bloody diarrhea: report of 21 cases with a long-term follow-up from Turkey.

Eur J Gastroenterol Hepatol 2012 Jun;24(6):688-94

Department of Infectious Diseases and Clinical Microbiology, Istanbul, Turkey.

Objective: Antibiotic-associated hemorrhagic colitis is a distinct form of antibiotic-associated bloody diarrhea (AABD) in which Clostridium difficile is absent. Although the cause is not exactly known, reports have suggested the role of Klebsiella oxytoca and/or C. difficile.

Materials And Methods: Between 2001 and 2006, stool samples of 21 consecutive patients with AABD were cultured for common enteric pathogens and K. oxytoca, and were tested for the presence of parasites and C. difficile toxin A+B within the first 24 h of their initial admission and a colonoscopy was performed when available. The patients were followed up prospectively by telephone interviews.

Results: The occurrence of symptoms ranged between 6 h and 14 days following the first dose of the antibiotic responsible and the duration of the AABD ranged between 6 h and 21 days. The antibiotic responsible was oral ampicillin/sulbactam in 18 (85%) cases. C. difficile toxin A+B production by enzyme-linked immunosorbent assay and K. oxytoca growth in stool cultures were detected in six (29%) and 11 (51%) of 21 patients, respectively. Endoscopic morphology and histology in a limited number of patients revealed no more than a nonspecific inflammation and acute colitis, respectively.

Conclusion: This study confirms that antibiotic-associated hemorrhagic colitis, as a distinct entity in relation to K. oxytoca, is seen in half of the patients with AABD. Most of the cases are seen within a week following the antibiotic use. Almost all of the patients did not develop any flares during the long-term antibiotic-free follow-up. In some of the patients with AABD, there was coexistence of K. oxytoca with C. difficile toxin A+B.
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http://dx.doi.org/10.1097/MEG.0b013e328352721aDOI Listing
June 2012

Novel influenza a (H1N1) infection in a Pediatric Hematology Oncology Clinic during the 2009-2010 pandemia.

Pediatr Hematol Oncol 2011 May 17;28(4):288-93. Epub 2011 Mar 17.

Department of Pediatric Hematology-Oncology, Cerrahpaşa Medical Faculty, Istanbul, Turkey.

Pandemic influenza A infection (2009 H1N1) was associated with a worldwide outbreak of febrile respiratory infection. Although usually it results in a mild illness, certain patient groups are at increased risk for complications. The authors reviewed their experience in a pediatric hematology-oncology unit to determine the outcome of this disease in children with hematological conditions and solid tumors. During the second outbreak (1 November 2009 to 14 January 2010), a total of 187 children from pediatric clinic were tested for H1N1 influenza A by multiplex polymerase chain reaction (PCR), 63 of them were positive. Patients' signs and symptoms were recorded prospectively. Ten (35.7%) (5 children with solid tumors, 4 with leukemia, 1 with hereditary spherocytosis) of 28 tested children with hematological conditions were diagnosed with 2009 H1N1 influenza infection. Fever (100%) and cough (90%) were the most common symptoms. Five were neutropenic (neutrophil count <1000/mm(3)), 4 had severe neutropenia (neutrophil count <500/mm(3)). Systemic antibiotics were given in 5 patients with the diagnosis of febrile neutropenia. Four were inpatients, others were hospitalized after the diagnosis. One patient required mechanical ventilation; however, he had concomitant invasive fungal infection. Eight patients were treated by oseltamivir, all tolerated the drug well. A total of 4 cases from 9 cancer patients had a delay in their planned chemotherapy for 7 to 15 days. Pandemic H1N1 influenza caused mild symptoms in children with cancer and/or hematological conditions but resulted in delay in anticancer therapy and increase in hospitalization and antibiotic usage.
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http://dx.doi.org/10.3109/08880018.2010.550986DOI Listing
May 2011

Nasopharyngeal tuberculosis.

Rev Laryngol Otol Rhinol (Bord) 2007 ;128(1-2):89-91

Istanbul University, Cerrahpa_a Faculty of Medicine, Department of Otolaryngology and Head-Neck Surgery, Istanbul, Turkey.

Unlabelled: Nasopharyngeal tuberculosis is a rare disorder. It usually occurs via hematogenous and lymphatic spread from coexistent pulmonary or systemic tuberculosis, and by airway during respiration or bacillary expectoration.

Material: we present a case of nasopharyngeal tuberculosis in a 50-year-old female patient presenting with a cervical mass and unilateral otitis media with effusion. The diagnosis was made by PCR and by isolation of Mycobacterium Tuberculosis on Loveinstein-Jensen cultures.

Conclusion: Nasopharyngeal tuberculosis may present with cervical mass, unilateral otitis media with effusion, and may mimic nasopharyngeal carcinoma. Furthermore, nasopharyngeal carcinoma may harbor foci of granulomatous reaction, and this feature may confuse the pathologist. However PCR carries the advantage to detect the DNA of Mycobacterium tuberculosis before its growth on culture. Even though it is rare, this entity must be considered in the differential diagnosis of the nasopharyngeal masses.
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August 2007

The value of Gram staining of catheter segments for rapid detection of peripheral venous catheter infections.

Diagn Microbiol Infect Dis 2006 Mar 19;54(3):165-7. Epub 2006 Jan 19.

Department of Microbiology and Clinical Microbiology, Cerrahpasa Medical Faculty, Istanbul University, 34303 Aksaray/Istanbul, Turkey.

Catheter-related bloodstream infections are common in hospitalized patients. Peripheral venous catheters (PVCs) are the most frequently used vascular access devices with usually low reported infection rates. We conducted a study to find the rate of PVC-related infections using semiquantitative (roll plate) and quantitative catheter culture techniques. We found significant growth in 9.5% of the PVCs by quantitative culture, which was predictive of a BSI in 43% of cases, which seems to be the major limitation of the method. We conclude that Gram stain is a fast and reliable diagnostic tool for rapid detection of PVC infection.
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http://dx.doi.org/10.1016/j.diagmicrobio.2005.09.006DOI Listing
March 2006