Venhar Gurbuz
Hacettepe University
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Featured researches published by Venhar Gurbuz.
Clinical and Vaccine Immunology | 2013
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
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
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
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
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 | 2017
Rahmi Tuna Tekin; Ener Cagri Dinleyici; Mehmet Ceyhan; Adem Karbuz; Nuran Salman; Murat Sutcu; Zafer Kurugöl; Yasemin Balliel; Melda Celik; Mustafa Hacimustafaoglu; Necdet Kuyucu; Meda Kondolot; Gulnar Sensoy; Ozge Metin; Soner Sertan Kara; Meltem Dinleyici; Omer Kilic; Cihangul Bayhan; Venhar Gurbuz; Emre Aycan; Aygun Memedova; Arzu Karli; Gulcin Bozlu; Solmaz Celebi
ABSTRACT The serogroup epidemiology of invasive meningococcal disease (IMD), which varies considerably by geographic region and immunization schedule, changes continuously. Meningococcal carriage data are crucial for assessing IMD epidemiology and designing f potential vaccination strategies. Meningococcal seroepidemiology in Turkey differs from that in other countries: serogroups W and B are the predominant strains for IMD during childhood, whereas no serogroup C cases were identified over the last 10 y and no adolescent peak for IMD was found. There is a lack of data on meningococcal carriage that represents the whole population. The aims of this multicenter study (12 cities in Turkey) were to evaluate the prevalence of Neisseria meningitidis carriage, the serogroup distribution and the related risk factors (educational status, living in a dormitory or student house, being a household contact with Hajj pilgrims, smoking, completion of military service, attending bars/clubs) in 1518 adolescents and young adults aged 10–24 y. The presence of N. meningitidis DNA was tested, and a serogroup analysis was performed using polymerase chain reaction. The overall meningococcal carriage rate was 6.3% (n = 96) in the study population. A serogroup distribution of the 96 N. meningitidis strains isolated from the nasopharyngeal specimens revealed serogroup A in 5 specimens (5.2%), serogroup B in 9 specimens (9.4%), serogroup W in 64 specimens (66.6%), and serogroup Y in 4 specimens (4.2%); 14 were classified as non-grouped (14.4%). No serogroup C cases were detected. The nasopharyngeal meningococcal carriage rate was 5% in the 10–14 age group, 6.4% in the 15–17 age-group, and 4.7% in the 18–20 age group; the highest carriage rate was found in the 21–24 age group (9.1%), which was significantly higher than those of the other age groups (p < 0.05). The highest carriage rate was found in 17-year-old adolescents (11%). The carriage rate was higher among the participants who had had close contact with Hajj/Umrah pilgrims (p < 0.01) or a history of upper respiratory tract infections over the past 3 months (p < 0.05). The nasopharyngeal carriage rate was 6.3% among adolescents and young adults in Turkey and was similar to the recent rates observed in the same age groups in other countries. The most prevalent serogroup was W, and no serogroup C cases were found. In conclusion, the present study found that meningococcal carriage reaches its peak level by age 17, the highest carriage rate was found in 21 - to 24 - year-olds and the majority of the carriage cases were due to serogroup W. Adolescents and young adult carriers seem to be a potential reservoir for the disease, and further immunization strategies, including adolescent immunization, may play a role in the control of IMD.
Journal of Vaccines and Vaccination | 2013
Zehra Diyar Tamburacı Uslu; Mehmet Ceyhan; Ener Cagri Dinleyici; Zafer Kurugöl; Bedriye Nuray Alpman; Eda Karadag Oncel; Venhar Gurbuz; Emre Aycan; Hasan Tezer; Belgin Gülhan
Background: Despite high vaccination coverage, pertussis continues to be a great public health problem. Adults and adolescents are source of infection for infants who are too young to be completely vaccinated. The aim of the study is detect if there is a household transmission of pertussis. Methods: Presence of Bordetella pertussis among the household contacts of the children who had had the positive result for Bordetella pertussis by real-time polymerase chain reaction was detected. Results: Of the 173 infants with clinical suspicion of pertussis, 48 (27.7%) turned out to be positive by PCR. The mothers of 19 (41.3% of all tested mothers) of them were also PCR positive for B. pertussis, being the family member most frequently infected. Conclusion: Despite high coverage of pertussis vaccination in Turkey, pertussis is prevalent both in incompletely protected infants and older children. High rate of presence of the bacteria in the household contacts depicts the importance of further pertussis booster vaccination in adolescents, adults and the targeted vaccination of the adults having close contacts with infants (cocoon strategy).
Human Vaccines & Immunotherapeutics | 2017
Ayse Buyukcam; Hüseyin Güdücüoğlu; Kamuran Karaman; Venhar Gurbuz; Emil Aliyev; Ates Kara; Mehmet Ceyhan
ABSTRACT Invasive pneumococcal infections among children are a serious public health problem in many countries, including Turkey. Pneumococcal conjugate vaccine has been included in Turkeys National Immunization Programme since 2009. We report the first two pediatric cases of invasive pneumococcal infection due to non-vaccine serotype 15A after pneumococcal conjugate vaccine implementation in Turkey. It is essential to monitor the countries’ own local seroepidemiologic data for detecting selective pressure of non-vaccine serotypes of S. pneumonia.
Journal of Clinical Medicine Research | 2015
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
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.