Zoran Ruzic

Prof. Dr. Zoran Ruzic

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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ZKZorana Kovacevic
Zorana Kovacevic
DTDragana Tomanić
Dragana Tomanić
Ivana S. CabarkapaIvana S. Cabarkapa
Ivana S. Cabarkapa
LJUBISA ŠARICLJUBISA ŠARIC
LJUBISA ŠARIC
JSJovan Stanojević
Jovan Stanojević
NKNebojša Kladar
Nebojša Kladar
Due to the emergence of antibiotic-resistant bacteria, the risk it represents to public health, and the possible consequences for animal health and welfare, there is an increasing focus on reducing antimicrobial usage (AMU) in animal husbandry. Therefore, a great interest in developing alternatives to AMU in livestock production is present worldwide. Recently, essential oils (EOs) have gained great attention as promising possibilities for the replacement of antibiotics. The current study aimed to test the potential of using a novel EO-based pharmaceutical formulation (Phyto-Bomat) in bovine mastitis treatment. The antibacterial activity was performed using the microdilution technique. Lactating dairy cows were treated with 15 mL of Phyto-Bomat in the inflamed quarter for 5 consecutive days in order to analyze blood and milk samples for thymol and carvacrol residues using gas chromatography and mass spectrometry (GC–MS). Antimicrobial activity expressed as the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) indicates that this formulation has the highest activity against Gram-positive strains. The dominant compounds in Phyto-Bomat were thymol and carvacrol, at 12.58 ± 1.23 mg/mL and 23.11 ± 2.31 mg/mL, respectively. The quantification of these two compounds in evaluated biological samples showed that 24 h after administration the concentration of thymol and carvacrol in milk samples was at the same level as before application. On the other hand, thymol and carvacrol were detectable in plasma samples even after 24 h post-treatment, with values ranging from 0.15–0.38 and 0.21–0.66 µg/mL, respectively. The tested formulation showed encouraging results of antibacterial activity against bovine mastitis pathogens, as well as the withdrawal period of dominant compounds, which implies that further testing regarding the bacteriological and clinical cure rates in clinical settings is needed.

27 June 2022 in Antibiotics
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ZKZorana Kovacevic
Zorana Kovacevic
JVJovana Vidović
Jovana Vidović
MEMihajlo Erdeljan
Mihajlo Erdeljan
Marko CincovićMarko Cincović
Marko Cincović
ZRZoran Ruzic
Zoran Ruzic
Olga HorvatOlga Horvat
Olga Horvat
The main subject of the research is the assessment of the knowledge, attitudes and behaviors of veterinarians regarding the use of antibiotics (AMU) and antimicrobial resistance (AMR) through a questionnaire conducted among veterinarians in the northern region of Serbia. A total of 62 respondents completed the questionnaire, which represents a response rate of 44.3%. Male veterinarians are less likely to be in the group of veterinarians with insufficient knowledge (p < 0.05). Veterinarians engaged in mixed practice (small and large animals) (p < 0.001) and veterinarians who have over 100 patients per month (p < 0.005) are also less likely to be in the group with insufficient knowledge of antimicrobial resistance. The proportion of those with insufficient knowledge is growing among veterinarians whose source is the Internet (p < 0.01), while the proportion of those with insufficient knowledge about antimicrobial resistance is declining among veterinarians whose source of information is continuous education (p < 0.05). The majority of the respondents (n = 59, 95.2%) completely agreed that AMR is a very big issue in the global health sector right now. Unfortunately, there are crucial gaps in the knowledge and attitudes of the surveyed participants. They do not appear to be aware of the importance of AMU in veterinary medicine and its influence on overall AMR, or the crucial part that non-prescribed antibiotics have in all of it. Positively, many veterinarians use good practice AMU guidelines in their everyday practice and in line with the global trend of AMU reduction, respondents have also decreased their AMU compared to the previous year.

14 November 2023 in Pathogens
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JSJovan Stanojević
Jovan Stanojević
MKMario Kreszinger
Mario Kreszinger
MRMiodrag Radinović
Miodrag Radinović
NKNebojša Kladar
Nebojša Kladar
DTDragana Tomanić
Dragana Tomanić
ZKZorana Kovacevic
Zorana Kovacevic
Mastitis is one of the most important diseases in dairy cows, leading to substantial economic losses associated with decreased milk production and quality. Early detection of changes in metabolic and milk parameters is crucial for maintaining animal welfare and milk quality. This study aimed to detect patterns in metabolic and milk composition parameters in Serbian dairy cows affected by mastitis. It also examined the relationship between these factors in cows with clinical and subclinical mastitis, as well as in healthy cows. This study included 60 Holstein-Friesian cows with the same body score condition that were in the same lactation phase. They were divided into three groups of 20: clinical and subclinical mastitis and a control group of healthy cows. The categorization was based on clinical udder health and the California mastitis test. Blood serum metabolic profiles were measured using a Rayto spectrophotometer (Shenzhen, China), and milk composition was determined using MilcoScanTM (Foss, Hilleroed, Denmark) and FossomaticTM (Foss, Hilleroed, Denmark) instruments. Significant increases in non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHB), total protein, globulin, urea, total bilirubin, magnesium, and enzyme activity were noted in mastitis-affected cows compared to healthy ones. Additionally, mastitis-affected cows had higher total protein and globulin levels and increased somatic cell counts (SCCs), while albumin concentrations were decreased. Furthermore, a negative correlation between total protein and lactose suggested inflammation leading to reduced lactose levels due to cell damage, infection, and lactose use by mastitis pathogens. Hence, indicators of the energy and protein status of the metabolic profile, together with the chemical composition of milk, may be significant diagnostic tools for detecting, monitoring, and predicting the outcome of mastitis in cows.

1 January 2022 in Zbornik Matice srpske za prirodne nauke
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DTDragana Z. Tomanić
Dragana Z. Tomanić
JSJovan B. Stanojević
Jovan B. Stanojević
Ivan Milan GalićIvan Milan Galić
Ivan Milan Galić
ZRZoran Ruzic
Zoran Ruzic
TKTijana B. Kukurić
Tijana B. Kukurić
ZKZorana Kovacevic
Zorana Kovacevic
Bovine mastitis is an important disease in the dairy industry responsi?ble for the welfare and significant economic losses in dairy cows. The treatment of choice for mastitis is the administration of antibiotics. However, this therapeutic choice has some disadvantages including presence of antibiotics residues in the milk, low cure rate as well as rapid increase in antibiotic-resistant pathogens. Therefore, new alternative approaches to antibiotics were investigated by different groups of researchers in order to find an effective approach for bovine mastitis therapy. This review was conducted in order to analyze different publications on usage of essential oils in relation to bovine mastitis. There are many in vitro studies for evaluating the antimicrobial efficacy of essential oils against many mastitis associated pathogens. In addition, numerous of tested essential oils have shown good efficacy with a wide range of minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). On the other hand, only several in vivo studies have focused on therapeutic effects of essential oils. Moreover, recent studies indicate the possibility of using essential oils in the fight against biofilm which could be promising fight against bovine mastitis since unsuccessful antibiotic treatment can be associated with the presence of biofilms.

6 March 2024 in Foods
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Suzana Vidakovic KnezevicSuzana Vidakovic Knezevic
Suzana Vidakovic Knezevic
SKSlobodan Knežević
Slobodan Knežević
Jelena Miloš VraneševićJelena Miloš Vranešević
Jelena Miloš Vranešević
DMDubravka Spasoje Milanov
Dubravka Spasoje Milanov
ZRZoran Ruzic
Zoran Ruzic
SKSunčica Kocić-Tanackov
Sunčica Kocić-Tanackov
Yersiniosis, one of the leading foodborne infections in the European Union, is caused by Yersinia enterocolitica. In this study, the antibacterial and antibiofilm effects of cinnamon (Cinnamomum zeylanicum Nees), clove (Syzygium aromaticum L.), oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.), thyme (Thymus vulgaris L.), and winter savory (Satureja montana L.) essential oils were investigated against Y. enterocolitica strains belonging to the bioserotype 4/O:3. Cinnamon essential oil showed the highest antibacterial activity, with an MIC value 0.09 µL/mL, followed by oregano and thyme essential oils, with MIC values from 0.09 to 0.18 µL/mL, and from 0.18 to 0.23 µL/mL, respectively. Thyme essential oil at 0.23 µL/g (MIC) and at 0.46 µL/g (2MIC) significantly (p < 0.05) reduced the number of Y. enterocolitica by 0.38 log CFU/g and 0.64 log CFU/g, respectively, in minced pork meat during storage at 4 °C for 4 days. The Y. enterocolitica strains formed biofilms at 15 °C and 37 °C in tryptic soy broth and Luria–Bertani broth, while no biofilms were obtained at 5 °C, and in meat broth nutrient media. Applying the minimum bactericidal concentrations of cinnamon, clove, oregano, rosemary, thyme, and winter savory essential oils on preformed biofilms led to significant reductions being observed in the range from 45.34% to 78.89%. A scanning electron microscopy assay showed the devastating impact of oregano and thyme essential oils on the morphology of Y. enterocolitica bacterial cells. In conclusion, the results of this study show that essential oils possess high anti-Yersinia and antibiofilm effects.

22 March 2025 in Molecules
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VVVladimir Vidović
Vladimir Vidović
IDIvana N Davidov
Ivana N Davidov
ZRZoran Ruzic
Zoran Ruzic
MEMihajlo Erdeljan
Mihajlo Erdeljan
AVAnnamaria Galfi Vukomanović
Annamaria Galfi Vukomanović
BBBojana Blagojević
Bojana Blagojević
This review explores the potential role of androgens in human breast cancer and female canine mammary tumors. Human breast cancer is one of the most common cancers affecting women globally, while female canine mammary tumors provide a natural model for the study of human breast cancer due to their similar histopathologies and molecular features. Androgen receptors, typically linked to male sex hormones, are present in up to 90% of human breast tumors. These receptors interact with estrogen-receptor signaling, suggesting their involvement in a complex mechanism in cancer progression. Androgen receptors have become key players in breast cancer biology, offering new targets for therapeutic strategies. The presence of these receptors in both human and canine tumors raises important questions about their role in the development of these malignancies. While the exact mechanisms remain to be fully elucidated, research suggests that targeting androgen-receptor signaling could be a novel therapeutic approach for both humans and canines. Further studies are necessary to fully understand the implications of androgen-receptor expression and to develop more effective targeted therapies for these cancers.