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Öğe Antimicrobial susceptibility and serotype distribution of pneumococci strains isolated from meningitis patients(2006) Firat M.; Ersoy Y.; Eşel D.; Bayraktar M.; Çaylan R.; Durmaz R.Treatment of life threatening pneumococcal infections such as meningitis has recently become problematic due to the emergence of antibiotic resistant strains. Antimicrobial susceptibility data usually derived from the studies that included all clinical pneumococcal isolates. However, resistance patterns of this microorganism isolated from meningitis cases in our country are not exactly known. The aim of this study was to determine the antimicrobial susceptibility and serotypes of Streptococcus pneumoniae strains isolated from meningitis cases. This retrospective study was designed in three university hospitals in Turkey and 72 pneumococci isolated from patients with meningitis were evaluated. In this study disk diffusion test and E-test methods were used to determine the susceptibility of pneumococci to some antibiotics. All S.pneumoniae isolates were serotyped using Quellung reaction. Although resistance for oxacillin was found by disc diffusion method in 11 isolates, only six of them were found to be resistant by E-test. By the latter procedure, no resistance was recorded against ceftriaxone and meropenem, while chloramphenicol resistance was found as 1.4%. In our study, erythromycin, ciprofloxacin and levofloxacin resistance were 2.8%, TMP-SMX resistance was 26.4%, while no vancomycin resistance was detected by disk diffusion. In evaluation of 72 pneumococci, we found 16 different serotypes and four isolates could not be serotyped. The serogroup 23 (n: 19) was the most common one followed by serotype 19 (n: 9) and serotype 14 (n: 7). Of six resistant isolates, three pneumococci were serogroup 23 and the remaining were from three different serotype/ serogroups 11, 14 and 19. As a result penicillin resistance in pneumococci isolated from meningitis was low and there was no resistance to ceftriaxone. It seems that ceftriaxone is an appropriate choice for empirical treatment of meningitis in our patients. These findings also revealed that pneumococcal polysaccharide capsule vaccines in use cover most of the invasive pneumococcal serotypes.Öğe Application of IWA standard water balance in strategic water loss analysis: Benefits and problems(Yildiz Technical University, 2021) Yilmaz S.; Ozdemir O.; Firat M.Water losses occurring in distribution systems have effect on the operating cost, water and energy efficiency, service quality, customer satisfaction, maintenance and new resource demand. The standard water balance recommended by International Water Association (IWA) were used for defining, analyzing, regularly monitoring the water balance and sub-components, and determining the weakness and strengths of system. Water Utilities in Turkey are required to fill the water balance annually in order to analyze and monitor the performance with the regulation published in year 2014. However, in the use of this table, important problems are experienced due to the lack of technical, technological, personnel and economic conditions, data representing the field are not used and in many cases the real performance of the system is not revealed. In this study, the importance of IWA water balance in water loss management and monitoring system performance is emphasized, and the benefits and advantages are detailed by analyzing the pilot regions. In addition, problems encountered during filling the water balance, mistakes made, incomplete or incorrectly filled data and other problems were discussed. It is thought that this study will constitute a reference for the technical personnel in Utilities for measuring the data, analyzing the components and interpreting the results. © Yildiz Technical University, Environmental Engineering Department. All rights reserved.Öğe Classification of annual precipitations and identification of homogeneous regions using K-Means method(2012) Firat M.; Dikbaç F.; Koç A.C.; Güngör M.Reliable and correct estimation of hydrological and meteorological processes is one of the major problems in regions with insufficient hydrologic information and data. The classification of the hydrological variables and determination of homogeneous regions are the most important steps of regional studies. The purpose of this study is to classify the annual total precipitation series and to identify the homogeneous regions by K-Means method. The K-means method, which is the simplest and most commonly used clustering method, divides a data set into clusters by minimizing the sum of the Euclidean distance between each feature vector and its closest cluster centre. The annual precipitation records and longitude, latitude and altitude values obtained of 188 stations operated by the National Meteorology Works (DMI) in Turkey were considered for clustering analysis. The number of clusters was determined as 7. Moreover, the regional homogeneity test was applied for testing the homogeneity of regions identified by clustering analysis.Öğe Determination of the most economical leakage level in the district-metered area with the optimization algorithm(EDP Sciences, 2024) Yilmaz S.; Ateş A.; Firat M.Failures and breaks occurring in water distribution networks (WDSs) create significant leakage volumes annually. System operating conditions deteriorate due to the increase in the rate of failure and leakage. Therefore, the failure rate and leakage volume should be reduced by applying the most appropriate methods. For this, the most economically suitable level must first be defined in each system or district-metered area. This study aims to define the most economical leakage level with the optimization algorithm in the district-metered area in water distribution systems. For this, network characteristics, subscriber information and water consumption, water production cost, failure rates, and other data in the isolated measurement area are considered. Ant lion optimization algorithm was used as the optimization algorithm in the study. The definition of the methods to be applied to reach the defined ELL level constitutes a reference for the implementers. Water utilities can continue their loss reduction strategies in the most economically efficient way with the help of this method. In the selected regions of the study area, pressure management application and active leakage method application were economical. Thus, it is possible to create a more effective and efficient leakage management plan in the isolated measurement area. It is thought that the results obtained from the study will serve as a reference for practitioners and technical personnel, especially in terms of determining the appropriate leakage target level for each isolated region. © The Authors, published by EDP Sciences.Öğe Investigation of serum IgG subclass distributions and anti-HBs response in healthy adults after hepatitis B vaccination(2005) Dinç But A.; Ersoy Y.; Özerol I.H.; Firat M.The aim of this study was to evaluate the distribution of serum total lgG (tlgG) subtypes before and after hepatitis B vaccinations in young adults and the relationship between anti-HBs titers and tlgG subtypes. Thirty-eight young adults (29 female, 9 male; age range: 18-20 years) who were the students of Malatya Health Care Profession High School were included in the study. Their anti-HBs and total anti-HBc markers' were negative. The study group were immunized with 20 ?g/mL recombinant HBV vaccine intramuscularly (Engerix B) at 0, 1st, and 6th months. The tlgG subtype distributions before vaccination and anti-HBs and tlgG subtype distributions after vaccination were investigated. Serum samples were collected one month after the third dose vaccination, and anti-HBs were found negative (<10 IU/ml) in 8 subjects (21%), low positive (10-100 IU/ml) in 14 subjects (37%), and high positive (>100 lU/ml) in 16 subjects (42%). There was no difference between the response groups in terms of tlgG subtype distributions obtained before vaccination. After vaccination, while there was no increase in the tlgG subtypes in the unresponsive group, increased lgG1 levels were determined in low and high response groups. The lgG1 increment ratio was more evident in high response cases. We concluded that lgG1 subtype titer was the most important indicator for the evaluation of the efficacy of active HBV immunization.
