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Featured researches published by Ahmet Emre Aycan.


Clinical and Vaccine Immunology | 2013

Acquisition of Meningococcal Serogroup W-135 Carriage in Turkish Hajj Pilgrims Who Had Received the Quadrivalent Meningococcal Polysaccharide Vaccine

Mehmet Ceyhan; Melda Celik; E. T. Demir; Venhar Gurbuz; Ahmet Emre Aycan; S. Unal

ABSTRACT Invasive meningococcal disease is a recognized public health problem worldwide, with a dynamic and changeable epidemiology. In Turkey, the second most common pathogenic meningococcal serogroup (after serogroup B) is W-135, including an epidemic in 2005, which has been strongly associated with Hajj pilgrims and their close contacts. In two studies conducted in 2010, we assessed meningococcal carriage in intending Turkish pilgrims to the Hajj when they attended to receive a plain polysaccharide vaccine against serogroups A, C, W-135, and Y and, upon their return, to determine the acquisition of meningococcal carriage by the pilgrims themselves and subsequently their household contacts. Nasopharyngeal swabs were obtained from pilgrims before the Hajj and upon their return. Swabs were then obtained from 39 household contacts of pilgrims who were shown to have acquired carriage during the Hajj. Of the 472 pilgrims before the Hajj, 63 (13%) were positive for meningococcal carriage, of which 52 cases (83%) were serogroup W-135. In the 296 pilgrims tested after the Hajj, 81 (27%) were positive for meningococcal carriage, including 74 (91%) with W-135. In 11 family members of pilgrims who acquired W-135 carriage at the Hajj, 10 (91%) had acquired carriage of serogroup W-135. This study illustrates the acquisition of meningococcal carriage, predominantly of serogroup W-135 by pilgrims attending the Hajj, and the transmission of this carriage to their family members on their return, explaining the source of W-135 meningococcal disease in Turkey.


Human Vaccines & Immunotherapeutics | 2014

Meningitis caused by Neisseria Meningitidis, Hemophilus Influenzae Type B and Streptococcus Pneumoniae during 2005–2012 in Turkey: A multicenter prospective surveillance study

Mehmet Ceyhan; Nezahat Gürler; Yasemin Ozsurekci; Melike Keser; Ahmet Emre Aycan; Venhar Gurbuz; Nuran Salman; Yildiz Camcioglu; Ener Cagri Dinleyici; Sengul Ozkan; Gulnar Sensoy; Nursen Belet; Emre Alhan; Mustafa Hacimustafaoglu; Solmaz Celebi; Hakan Uzun; Ahmet Faik Öner; Zafer Kurugöl; Mehmet Ali Tas; Denizmen Aygun; Eda Karadag Oncel; Melda Celik; Olcay Yasa; Fatih Akin; Yavuz Coşkun

Successful vaccination policies for protection from bacterial meningitis are dependent on determination of the etiology of bacterial meningitis. Cerebrospinal fluid (CSF) samples were obtained prospectively from children from 1 month to ≤ 18 years of age hospitalized with suspected meningitis, in order to determine the etiology of meningitis in Turkey. DNA evidence of Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae), and Hemophilus influenzae type b (Hib) was detected using multiplex polymerase chain reaction (PCR). In total, 1452 CSF samples were evaluated and bacterial etiology was determined in 645 (44.4%) cases between 2005 and 2012; N. meningitidis was detected in 333 (51.6%), S. pneumoniae in 195 (30.2%), and Hib in 117 (18.1%) of the PCR positive samples. Of the 333 N. meningitidis positive samples 127 (38.1%) were identified as serogroup W-135, 87 (26.1%) serogroup B, 28 (8.4%) serogroup A and 3 (0.9%) serogroup Y; 88 (26.4%) were non-groupable. As vaccines against the most frequent bacterial isolates in this study are available and licensed, these results highlight the need for broad based protection against meningococcal disease in Turkey.


Clinical and Vaccine Immunology | 2013

Distribution of Streptococcus pneumoniae Serotypes That Cause Parapneumonic Empyema in Turkey

Mehmet Ceyhan; Yasemin Ozsurekci; Nezahat Gürler; Sengul Ozkan; Gulnar Sensoy; Nursen Belet; Mustafa Hacimustafaoglu; Solmaz Celebi; Melike Keser; Ener Cagri Dinleyici; Emre Alhan; Ahmet Faik Öner; Hakan Uzun; Zafer Kurugöl; Ahmet Emre Aycan; Venhar Gurbuz; Eda Karadag Oncel; Melda Celik; Aslinur Ozkaya Parlakay

ABSTRACT Streptococcus pneumoniae is the most common etiological cause of complicated pneumonia, including empyema. In this study, we investigated the serotypes of S. pneumoniae that cause empyema in children. One hundred fifty-six children who were diagnosed with pneumonia complicated with empyema in 13 hospitals in seven geographic regions of Turkey between 2010 and 2012 were included in this study. Pleural fluid samples were collected by thoracentesis and tested for 14 serotypes/serogroups using a Bio-Plex multiplex antigen detection assay. The serotypes of S. pneumoniae were specified in 33 of 156 samples. The mean age ± the standard deviation of the 33 patients was 6.17 ± 3.54 years (range, 0.6 to 15 years). All of the children were unvaccinated according to the vaccination reports. Eighteen of the children were male, and 15 were female. The serotypes of the non-7-valent pneumococcal conjugated vaccine (non-PCV-7), serotype 1, serotype 5, and serotype 3, were detected in eight (14.5%), seven (12.7%), and five (9.1%) of the samples, respectively. Serotypes 1 and 5 were codetected in two samples. The remaining non-PCV-7 serotypes were 8 (n = 3), 18 (n = 1), 19A (n = 1), and 7F/A (n = 1). PCV-7 serotypes 6B, 9V, 14, 19F, and 23F were detected in nine (16.3%) of the samples. The potential serotype coverages of PCV-7, PCV-10, and PCV-13 were 16.3%, 45.4%, and 60%, respectively. Pediatric parapneumonic empyema continues to be an important health problem despite the introduction of conjugated pneumococcal vaccines. Active surveillance studies are needed to monitor the change in S. pneumoniae serotypes that cause empyema in order to have a better selection of pneumococcal vaccines.


Journal of Medical Virology | 2012

The Prevalence of Different HPV Types in Turkish Women With a Normal Pap Smear

Esra Tamburaci Demir; Mehmet Ceyhan; Mehmet Simsek; Tonguc Gunduz; Sefa Arlier; Ruşen Aytaç; Ahmet Emre Aycan; Venhar Gurbuz

The age‐specific human papillomavirus (HPV) seroprevalence and HPV type distribution in women with normal cervical cytology were studied. Cervical smear samples obtained using liquid‐based smears from 582 clinically healthy women aged between 15 and 68 years from five centers from four different regions of Turkey, were studied between February 2010 and January 2011. Overall, 530 of the women with normal cytology were included and the samples were analyzed for the presence of HPV by AmpliTaq. Positive samples were typed further for 37 different HPV genotypes by a line blot assay. HPV was positive in 17.9% of the women. HPV prevalence was highest in the age group of 25–29 years (31.8%), and decreased with increasing age. HPV 16 was the most common type (3.6%) followed by type 6 (2.6%) and type 45 (2.2%). Types 11 and 18 were rare (0.6% and 0.4%, respectively). Among the risk factors, number of sexual partners and parity were positively correlated with HPV positivity. In the present study, a large number of sex partners and high parity increased the risk for HPV infection. The age‐specific distribution of HPV in women with normal Pap smears did not show a U‐shaped curve in contrast to European countries and the USA. J. Med. Virol. 84: 1242–1247, 2012.


Jornal De Pediatria | 2016

Can procalcitonin be a diagnostic marker for catheter‐related blood stream infection in children?

Yasemin Ozsurekci; Kamile Oktay Arıkan; Cihangul Bayhan; Eda Karadag-Oncel; Ahmet Emre Aycan; Venhar Gurbuz; Gulsen Hascelik; Mehmet Ceyhan

OBJECTIVE The potential role of procalcitonin (PCT) in the diagnosis of catheter-related bloodstream infection (CRBSIs) is still unclear and requires further research. The diagnostic value of serum PCT for the diagnosis of CRBSI in children is evaluated here. METHOD This study was conducted between October 2013 and November 2014, and included patients with suspected CRBSI from 1 month to 18 years of age who were febrile, with no focus of infection, and had a central venous catheter. Levels of PCT and other serum markers were measured, and their utility as CRBSI markers was assessed. Additionally, the clinical performance of a new, automated, rapid, and quantitative assay for the detection of PCT was tested. RESULTS Among the 49 patients, 24 were diagnosed with CRBSI. The PCT-Kryptor and PCT-RTA values were significantly higher in proven CRBSI compared to those in unproven CRBSI (p=0.03 and p=0.03, respectively). There were no differences in white blood cell count and C-reactive protein (CRP) levels between proven CRBSI and unproven CRBSI. Among the 24 patients with CRBSI, CRP was significantly higher among those with Gram-negative bacterial infection than in those with Gram-positive bacterial infections. PCT-Kryptor was also significantly higher among patients with Gram-negative bacterial infection than in those with Gram-positive bacterial infections (p=0.01 and p=0.02, respectively). CONCLUSIONS The authors suggest that PCT could be a helpful rapid diagnostic marker in children with suspected CRBSIs.


Human Vaccines & Immunotherapeutics | 2018

Neisseria meningitidis Serogroup X ST-5799 (ST-22 complex) in Turkey: A unique pediatric case

Gonul Tanir; Yasemin Ozsurekci; Jay Lucidarme; Sevgi Yaşar Durmuş; Aiswarya Lekshmi; Özlem Akisoglu; Ahmet Emre Aycan; Ray Borrow; Mehmet Ceyhan

ABSTRACT Although outbreaks of Neisseria meningitidis serogroup X occured in a couple of African countries, a limited number of serogroup X meningococcal cases were reported in America and Europe as well as Turkey. Additionally, serogroup X is still not represented in current conjugated meningococcal vaccines. Here, we describe the first pediatric case with meningitis caused by Neisseria meningitidis serogroup X ST-5799 (ST-22 complex) that formed a distinct lineage.


Journal of Clinical Medicine Research | 2015

Determination of the Presence of Diphtheria Toxin in the Myocardial Tissue of Rabbits and a Female Subject by Using an Immunofluorescent Antibody Method

Mehmet Ceyhan; Yasemin Ozsurekci; Merve M. Aydin; Kamil Can Akcali; Beril Talim; Melda Celik; Eda Karadag Oncel; Venhar Gurbuz; Ahmet Emre Aycan; Ilyas Onbasilar; Turan Buzgan

Background Clinical diagnosis of diphtheria is often difficult, in particular in countries where the disease is rarely observed, such as Turkey. In 2011, after 12 years of no recorded diphtheria cases in Turkey, a 34-year-old woman was diagnosed with diphtheria; she later died of myocarditis. In this study, we aimed to demonstrate the diagnostic potential of an immunofluorescent antibody method to determine the presence of diphtheria toxin (DT) in the myocardial cells of DT-injected rabbits and the female subject. Methods We randomly divided rabbits into two groups: a control group and a DT-injected group. Diphtheria intoxication was simulated in the rabbits by intravenous injection of DT. The myocardium of the rabbits and the female subject were harvested for histopathologic and immunofluorescence examination. A mouse monoclonal anti-DT antibody was used for the immunofluorescent antibody method. Results The presence of DT in the myocardial cells of both the rabbits and the female subject was visualized using the immunofluorescent method. Conclusions Laboratory diagnosis of diphtheria is challenging because of non-toxigenic C. diphtheriae strains and/or the dysfunction of DT. However, visualizing the presence of DT in the myocardial tissue may act as an indicator of biologically active DT. We validated that an immunofluorescent method, which utilizes a monoclonal anti-DT (A-subunit specific) antibody, is a useful diagnostic tool to determine the presence of DT in the myocardium of rabbits and human.


Journal of Vaccines and Vaccination | 2014

Bacterial Etiology and Pneumococcal Serotypes in Turkish Children with Acute Otitis Media

Mehmet Ceyhan; Yasemin Ozsurekci; Nezahat Gürler; Eda Karadag Oncel; Melda Celik; Ahmet Emre Aycan; Venhar Gurbuz; Adnan Karabent; Mehmet Ada; Emre Alhan; Özlem Özgür

Background: Acute otitis media (AOM) is one of the most common childhood diseases requiring antimicrobial prescription drugs in pre-school children. In this study, we sought to describe the bacterial etiology of pediatric cases of AOM in Turkey. Materials and Methods: This prospective, multi-center, tympanocentesis-based epidemiological study was performed during 2010-2012in children aged between3 months and 6 years. All isolates were cultured and sero grouped by the Quellung reaction. Results: During 2010-2012, 38 cases fulfilled the study inclusion criteria. Overall, 45% of samples were culture positive for bacterial pathogens Streptococcus pneumonia (13.1%) was the leading cause of bacterial AOM followed by Streptococcus pyogenes (10.5%) and H. influenzae (7.9%). Serotype-3 was detected in two of the samples, and serotypes 9V, 19, and 19A were isolated from one patient each. S. pneumoniae was detected in 36% (4/11) of otorrhea samples. All H. influenzae- positive samples were collected by tympanocentesis. All H. influenzae isolates were identified as non-typeable. The pneumococcal serotype coverage rates for PCV-7, PVC-10 and PCV-13 were 20% (1/5), 20% (1/5), and 80% (4/5), respectively. PHiD-CV (PCV-7 types plus 1, 5, and 7F) targets non-typeable H. influenzae , and 4 of 38 (11%) of the pathogens causing episodes of AOM were also covered. Conclusion and Recommendation: In Turkey, S.pneumonia remains the most common pathogen in children with AOM. Both S. pneumonia and non-typeable H. influenzae represent important targets for vaccination strategies to reduce AOM in children. Based on our results, conjugated pneumococcal vaccines may have potential impact to decrease the burden of AOM.


Journal of Infection and Chemotherapy | 2018

Presepsin: A new marker of catheter related blood stream infections in pediatric patients

Sevgen Tanır Basaranoglu; Eda Karadag-Oncel; Kubra Aykac; Yasemin Ozsurekci; Ahmet Emre Aycan; Ali Bulent Cengiz; Ates Kara; Mehmet Ceyhan


Journal of Infection and Chemotherapy | 2018

Presepsin: A new marker of catheter related blood stream infections in pediatric patients: Reply to Rivera-Moran Javier et al

Sevgen Tanır Basaranoglu; Eda Karadag-Oncel; Kubra Aykac; Yasemin Ozsurekci; Ahmet Emre Aycan; Ali Bulent Cengiz; Ates Kara; Mehmet Ceyhan

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