Authors:Milica Jovanovic, Veljko Jeremic, Gordana Savic, Milica Bulajic, and Milan Martic
The aim of this paper is to present new ideas in evaluating Shanghai University's Academic Ranking of World Universities (ARWU). In particular, this paper shall try to determine whether the normalization of data affects University ranks. In accordance with this, both the normalized and original (raw) data for each of the six variables has been obtained. Based on a sample containing the 54 US universities which are placed in the ARWU top 100, the statistical I-distance method was performed. The results showed great inconsistencies between university ranks obtained for the original and normalized data. These findings were then analyzed and the universities that had the greatest fluctuation in their ranks were noted.
The field experiment with fertilizer „Njival Ca“ (waste of the Serbian glas factory in Paracin: calcite 98.5% CaCO
, granulation <0.1 mm) was conducted in spring 1998 on the Kragujevac vertisol with the treatments as follows (t ha
basis): 0 (the control), 0.8 and 1.6 (every year), 4.0 and 8.0 (at start of the experiment). The trial was conducted in five replicates and in triplicate for wheat-maize-soybean roration. In general, limiting considerably influenced on yields of the field crops and single application of the high rates are better choice in comparison with repeated use of the low rates. For example, by yield increases in comparison with the control were as follows (comparison single application of 8 t ha
and repeated applications of 1.6 t ha
): 29% and 9% (maize), 7% and 3% (wheat), 24% and 9% (soybean), respectively.
Methicillin-resistant Staphylococcus aureus (MRSA) emerged as one of the most important causes of hospital-acquired bloodstream infections (BSIs), especially the multidrug resistant clones. The aim of the present study was to compare prevalence and resistance patterns of MRSA bacteremia in the major tertiary-care academic and referral center in Serbia before and after implementing an active antimicrobial resistance (AMR) surveillance. Laboratory-based before-after study was conducted during a two-year period (January 2012 to December 2013) in Clinical Centre of Serbia. Isolation and identification of bacterial strains were done following standard microbiological procedures. During the AMR surveillance, nearly twice more bloodstream samples were collected compared to the year without surveillance (1,528 vs. 855). In total, 43 isolates of MRSA were identified. MRSA was significantly more prevalent during the AMR surveillance compared to the previous year [14 (66.7%) to 29 (76.3%); P = 0.046]. During the AMR surveillance, MRSA more frequently originated from medical departments compared to intensive care unit, surgical department, and internal medicine (P = 0.027) indicating increasing MRSA infections in patients with less severe clinical condition and no apparent risk factors. Higher prevalence of MRSA and its lower susceptibility to erythromycin were revealed by implementation of active AMR surveillance, which may reflect more thoughtful collection of bloodstream samples from patients with suspected BSI.
Authors:Milica Jovanović, Branko Milošević, Tanja Tošić, Goran Stevanović, Vesna Mioljević, Nikola Inđić, Branko Velebit, and Marcus Zervos
In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness.
Authors:Milica Jovanović, Sofie M. van Dorp, Mitra Drakulović, Dubravka Papić, Sladjana Pavić, Snežana Jovanović, Aleksandar Lešić, Miloš Korać, Ivana Milošević, and Ed J. Kuijper
Clostridium (Clostridioides) difficile infections (CDIs) are among the most frequent healthcare-associated infections in Serbia. In 2013, Serbia participated in the European Clostridium difficile Infection Surveillance Network (ECDIS-Net) who launched a pilot study to enhance laboratory capacity and standardize surveillance for CDI. Two clinics of Clinical Center of Serbia [Clinic for Infectious and Tropical Diseases (CITD) and Clinic of Orthopedic Surgery and Traumatology (COT)] from Belgrade and one general hospital from another metropolitan area of Serbia, Užice, participated. During a period of 3 months in 2013, all patients with diagnosed CDI were included. The CDI incidence rates in CITD, COT, and General Hospital Užice were 19.0, 12.2, and 3.9 per 10,000 patient-days, respectively. In total, 49 patients were enrolled in the study with average age of 72 years. A complicated course of CDI was found in 14.3% of all patients. Six (12.2%) of 49 patients died, but not attributable to CDI. Of 39 C. difficile isolates, available for ribotyping, 78.9% belonged to ribotype 027; other PCR ribotypes were 001, 015, 002, 005, 010, 014, and 276. Antimicrobial susceptibility testing revealed low levels of MIC50 and MIC90 for metronidazole (0.5 μg/ml both) and vancomycin (0.25 and 0.5 μg/ml), while 28 strains of ribotype 027 were resistant to moxifloxacin with MIC ≥4 μg/ml. National surveillance is important to obtain more insight in the epidemiology of CDI and to compare the results with other European countries. This study by ECDIS-Net gives bases for a national surveillance of CDI in Serbia.
Authors:Milica Jovanović, Branko Milošević, Olga Dulović, Mijomir Pelemiš, Goran Stevanović, Tanja Tošić, Branka Stošović, and M.J. Zervos
The purpose of this study was to evaluate the molecular relatedness of clinical isolates of vancomycin-resistant enterococci (VRE) collected from patients of the Clinic for Infectious and Tropical Diseases in Belgrade. Among 40 isolates available for the investigation, 36 were identified as Enterococcus faecium, whereas 2 were Enterococcus faecalis and Enterococcus raffinosus, respectively. Pulsed-field gel electrophoresis (PFGE) typing revealed 21 strain types, comprising 7 clusters which contained at least two isolates and 14 unique PFGE patterns. Although we searched for pathogenicity factor genes (gelE, cylB, asa1, efaAfs, esp, cpd, cob) in representatives of all macro-restriction patterns, they have been confirmed in only one clone of E. faecalis. Genes esp and hyl, commonly found in E. faecium, were yilded in 10 macro-restriction patterns of this species, and their presence could not be ascribed to clonally related strains (p = 0.05). All VRE isolates were multiresistant and positive for vanA gene. Twenty strains of VRE and 6 clusters obtained from Intensive care unit (ICU) are proof of intensive transmission of these microorganisms at this department. The results of this study suggest wide genotypic variability among the clinical VRE isolates, but also intrahospital dissemination of some of them.
Authors:Adam Šuluburić, Svetlana Milanović, Sanja Vranješ-Đurić, Ivan B. Jovanović, Tomislav Barna, Milica Stojić, Natalija Fratrić, Ottó Szenci, and Dragan Gvozdić
Early embryonic development may be negatively affected by insufficient progesterone (P4) production. Therefore, the aim of our study was to increase P4 by gonadotropin-releasing hormone (GnRH) and/or human chorionic gonadotropin (hCG) treatments after inducing oestrus by prostaglandin (PG) treatment. Lactating Simmental dairy cows (n = 110), between 1 to 5 lactations, with an average milk production of 6,500 1/305 days, at 40–80 days postpartum were used and grouped as follows: (1) PG + GnRH treatment at AI (GnRH group), (2) PG + hCG treatment at day 7 after AI (hCG group), (3) PG + GnRH at AI + hCG treatment at day 7 after AI (GnRH/hCG group), and (4) spontaneous oestrus (C: control group). All animals were double inseminated (at the time of oestrus detection and 12 ± 2 h thereafter). Blood serum and milk samples were collected at the day of observed oestrus (day 0), and 14, 21 and 28 days after AI. Serum P4 was determined using a commercial radioimmunoassay (RIA) test (INEP, Zemun), and milk P4 was determined using enzyme-linked immunoassay (ELISA) test (NIV Novi Sad). Pregnancy status was confirmed by ultrasonography between days 28 and 35 after AI. Differences of serum or milk P4 medians, pregnancy (and calving) rate were determined using Dunn’s Multiple Comparison Tests and Z test, respectively. Serum P4 medians were significantly higher at days 14, 21 and 28 after AI in the hCG-treated animals, indicating increased luteal activity, with a similar tendency in whole milk P4 values. Treatment with hCG during the early luteal phase significantly contributed to the maintenance of gestation at days 28–35 after AI, and also increased the calving rate in Simmental dairy cows.
Authors:Svetlana Jovanovic, Olaf C. Haenssler, Milica Budimir, Duška Kleut, Jovana Prekodravac, and Biljana Todorovic Markovic
In order to modify both chemical and electrical properties of graphene-based nanomaterials, we conducted the chemical modification of graphene oxide (GO) and graphene quantum dots (GQDs). The reaction of the reduction with nascent hydrogen was conducted on both materials. The structure and morphology of produced chemically reduced GO and GQDs were analyzed. While the chemical composition of both GQD and GO changed significantly, GO showed also significant changes in morphology as opposite to GQDs where were morphological changes were not observed.