Pseudomonas aeruginosa Antimicrobial Susceptibility Results at a State Hospital in Turkey (2010-2016)

Pseudomonas aeruginosa, nozokomiyal pnömoni, dolaşım sistemi infeksiyonları, üriner infeksiyon ve deri infeksiyonları gibi sağlık hizmetleri gerektiren infeksiyon etkenlerinin önemli bir bölümünü oluşturur. Bu çalışma, yıllara göre P.aeruginosa'nın antimikrobiyal duyarlılığının değişimini belirleyerek antimikrobiyal kullanım politikasının oluşturulmasına yardımcı olmayı amaçlamıştır.Hastanemizde 2010-2016 yılları arasında izole edilen P.aeruginosa suşlarının antimikrobiyal duyarlılıkları, örnek türleri ve hastaların demografik verileri retrospektif olarak incelenmiştir. Verileri aktarmak ve analiz etmek için Windows istatistik paket programı PASW Statistics 18 kullanılmıştır. Değişkenler arasındaki ilişkiler ki-kare testi ile analiz edilmiştir.Yatarak tedavi olan, 0-92 yaş aralığında bulunan 350 (% 35.9) kadın ve 625 (% 64.1) erkek hastadan 975 P.aeruginosa suşu izole edilmiştir. Örneklerin çoğunluğunun (529, % 54.3) yoğun bakım ünitesinde yatan hastalara ait olduğu tespit edilmiştir. P.aeruginosa, en sık solunum sistem örneklerinde izole edilmiştir. Ayakta tedavi gören, yaşları 0-95 arasında değişen 127 (% 33.1) kadın ve 257 (% 66.9) erkek hastada üreme saptanmıştır. Kliniklere göre dağılımına bakıldığında en sık pediatri polikliniğinden gelen örneklerde izole edilmiştir. Ayaktan tedavi gören hastaların en sık idrar örneğinde izole edilmiştir. En etkili antibiyotiklerin ayaktan hastalarda amikasin, piperazin-tazobaktam, imipenem ve meropenem, yatarak tedavi gören hastalarda aminoglikozid ve karbapenem olduğu tespit edilmiştir. Yıllara göre yatan hastalarda seftazidim, piperasilin-tazobaktam, gentamisin ve amikasin duyarlılığında artış, ayaktan hastalarda piperasilin-tazobaktam ve siprofloksasin duyarlılığında ise azalma görülmüştür.Klinik sonuçların optimizasyonu için etkili antimikrobiyal tedavinin hızlı başlatılmasının gerekli olduğu göz önüne alındığında, her hastane duyarlılık oranlarını izlemelidir. Böylece ampirik antimikrobik seçimi ve uygun tedavinin belirlenmesi için bir kılavuz oluşturulmalıdırPseudomonas aeruginosa constitutes an important part of infections requiring health care services such as nosocomial pneumonia, circulatory infections, urinary infection and skin infections. The present study aimed to help in creating an antimicrobial usage policy by identifying the change of antimicrobial susceptibility of P.aeruginosa according to years. The antimicrobial susceptibility of P.aeruginosa strains isolated between 2010-2016 in our hospital, specimen types and demographic data of the patients were examined retrospectively. PASW Statistics 18 for Windows statistical pack age program was used to transfer and analyze the data. The relation ships among variables were analyzed with the chi-square test. Nine hundred seventy-five P.aeruginosa strains were isolated from 350 (35.9 %) female and 625 (64.1 %) male patients who were in the age range of 0 to 92 years and who were treated as in patients in our hospital between 2010-2016. The majority of the specimens (529, 54.3 %) belonged to the patients from the intensive care unit. P.aeruginosa was most frequently isolated in respiratory tract specimens of in patients. Of the out patients, 127 (33.1 %) were female and 257 (66.9 %) were male and they were aged between 0-95 years. Considering the distribution of the patients according to the outpatient clinics, P.aeruginosa was most frequently isolated in pediatrics. In respect to the out patients P.aeruginosa was most frequently isolated in urine. The most effective antimicrobials were determined to be aminoglycosides and carbapenems for the in patients while they were found to be amikacin, piperacillin-tazobactam, imipenem and meropenem for the out patients. In patients were showed increased sensitivity of ceftazidime, piperacillin-tazobactam, gentamicin and amikacin, for years and outpatients were decreased sensitivity of piperacillin-tazobactam and ciprofloxacin. Considering that the rapid initiation of effective antimicrobial treatment is necessary for the optimization of clinical outcome, each hospital should monitor their susceptibility rates. Thus, a guidelines hould be created for the selection of empirical antimicrobial therapy and determination of appropriate treatment

Analyses of elastic limit heat loads in thick walled tubes subjected to periodic surface temperatures: analytical treatment

ANALYTICAL SOLUTIONS ARE DERIVED TO ANALYZE elastic limit heat loads in tubes subjected to periodic surface temperatures. The tube is initially at zero temperature and for the times greater than zero one of the surfaces of the cylinder is subject to a periodic boundary condition while the other surface is insulated. For the transient temperature distribution, the heat conduction equation is solved by using Duhamel's theorem. The uncoupled theory of thermoelasticity is used as the cylinder is heated or cooled slowly. Tresca's yield criterion is used to monitor the yielding of the tube. The generalized plane strain condition is assumed. It is observed that yielding always occurs at the surface subject to a periodic boundary condition. It is also observed that, depending on the material properties of the tube and the amplitude of the boundary condition, yielding commences with different stress states

Analytical Solution of Nonlinear Strain Hardening Preheated Pressure Tube

The analytical solution of a nonlinear strain hardening preheated tube subjected to internal pressure is presented. A state of generalized plane strain, small deformations, and temperature gradients are assumed. The analytical plastic model is based on the incremental theory of plasticity, Tresca´s yield criterion, its associated flow rule, and a Swift-type nonlinear hardening law. Solutions for linearly hardening and perfectly plastic materials are also presented

Analytical solution to thermal loading and unloading of a cylinder subjected to periodic surface heating

An attempt is made to develop an analytical model for the prediction of thermal loading into a partially plastic state and unloading into an elastic state of a cylinder subjected to periodic boundary condition. The uncoupled theory of thermoelasticity is used as the cylinder is heated or cooled slowly. Transient temperature distribution in the cylinder is obtained by the use of Duhamel's theorem. It is assumed that the ends of the cylinder are free and hence a state of generalized plane strain is operative in the axial direction. An elastic and two plastic regions with different mathematical forms of Tresca's yield condition are formulated and solved analytically. Linearly hardening material behavior is assumed. Sudden unloading approximation is used to model unloading into a plastically predeformed elastic region. The model is verified in comparison to a purely numerical solution and by observing satisfaction of equilibrium, interface, and boundary conditions in every stage of deformation

Investigation of Antibiotic Susceptibility of Acinetobacter baumannii Isolated from Clinical Specimens (2010-2016)

Introduction: Since Acinetobacter baumannii has low virulence, it generally does not cause infection in individuals with a normal host defense. A. baumannii may particularly cause infections such as ventilator-associated pneumonia, bacteremia, urinary tract infections, skin and wound infections in patients admitted to intensive care units. Its treatment is challenging since Acinetobacter species develop multidrug-resistance. In this study, antibiotic resistance rates of A. baumannii species isolated from various clinical samples in our hospital were evaluated. Materials and Methods: Antibiotic sensitivity of A. baumannii species isolated in our hospital between January 2010 and May 2016 was evaluated. Sample types were also analyzed. Results: Among the patients with an age range of 0-96 years, 437 (61.8%) were males and 270 (38.2%) were females. Majority of the patients were admitted to the intensive care unit. Sensitivity of amikacin, ceftazidime, ciprofloxacin, gentamicin, colistin, imipenem, meropenem, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, tigecycline and piperacillin-tazobactam was found to be 37%, 5.7%, 6.6%, 31%, 96.5%, 16%, 13.1%, 3.9%, 11.7%, 93.9% and 7.4%, respectively. Sensitivity of ampicillin-sulbactam, ceftazidime, piperacillin-tazobactam, trimethoprim-sulfamethoxazole and ciprofloxacin was found continuously low in years. On the other hand, sensitivity of imipenem, meropenem, gentamicin and amikacin was found to have decreased since 2014. The most sensitive antibiotics was found to be colistin and tigecycline for A. baumannii in this study. Notably, sensitivity of gentamicin increased up to 70% in 2016, which is considered to be associated with species including aac(6’)-Iad gene. Conclusion: Colistin and tigecycline emerged as the most sensitive antibiotics in A. baumannii infections for our hospital. Knowledge of the resistance rates in an institution helps the clinician to decide on the empirical antibiotic treatment and to the infectious disease specialist in defining the appropriate treatment protocols

ELASTIC-PLASTIC STRESS ANALYSIS OF NONHOMOGENEOUS ROTATING SOLID DISCS

A computational model is developed for the analysis of elastic and partially plastic stress states in functionally graded (FGM) variable thickness rotating solid disks. The modulus of elasticity, Poisson's ratio, uniaxial yield limit and density of the disk material are assumed to vary radially in any prescribed functional forms. Small deformations and a state of plane stress are presumed. Using the von Mises yield criterion, total deformation theory and a Swift-type nonlinear hardening law, a single nonlinear equation describing elastoplastic behavior of rotating disk is obtained. A shooting technique using Newton iterations with numerically approximated tangents is designed and used for the computer solution of the governing equation. The model is verified by comparing predictions with analytical solutions

Sinüzoidal Değişen İç Isı Üretimi Etkisindeki Silindirin Kısmen Plastik Analitik Çözümü

In this theoretical investigation, analytical solutions to thermally induced elastic and partially plastic deformations of a solid cylinder under periodic internal heat generation are derived. The analytical unsteady temperature distribution in the cylinder is formulated by the use of Duhamel’s theorem. Tresca’s yield criteria and the corresponding flow rules are utilized in the treatment of plastic deformation. Furthermore, the material of the cylinder is assumed to behave linearly during hardening. In both elastic and partially plastic deformations a state of generalized plane strain is taken into account. It is observed that the surface of the cylinder is critical and plastic deformation always commences there. It is also observed that the evolution of two adjacent plastic regions halt as soon as the temperature gradient reaches it’s maximum and just begins to draw back.Bu teorik çalışmada, periyodik iç ısı üreten bir silindirin elastik ve kısmen plastik davranışlarının analitik çözümleri türetilmiştir. Silindir içerisindeki sıcaklık dağılımının analitik ifadesi Duhamel Teoremi yardımıyla elde edilmiştir. Plastik deformasyonun formülasyonunda Tresca akma kriterleri ve karşılık gelen akış kurallarından yararlanılmıştır. Bu bağlamda, silindir malzemesinin lineer olarak pekleştiği varsayılmaktadır. Hem elastik hem de kısmen plastik çözümlerde genelleştirilmiş birim düzlem şekil değiştirme durumu kabul edilmektedir. Silindirin yüzeyinin kritik olduğu ve plastik deformasyonun daima bu bölgede başlayacağı gözlemlenmiştir. Buna ilave olarak, birbirine bitişik iki plastik bölgenin silindir yüzeyinden içeri zamanla genişlemelerinin sıcaklık gradyanının maksimuma erişip düşmeye başladığı ana kadar devam ettiği de gözlemlenmiştir