Zorana Kovacevic

Prof. Dr. Zorana Kovacevic

Univerity of Novi Sad
orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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30 March 2023 in Antibiotics
Verified
Journal Article
Open access
PDF file
DTDragana Tomanić
Dragana Tomanić
MSMarko Samardžija
Marko Samardžija
ZKZorana Kovacevic
Zorana Kovacevic
Despite preventive and therapeutic measures, mastitis continues to be the most prevalent health problem in dairy herds. Considering the risks associated with antibiotic therapy, such as compromised effectiveness due to the emergence of resistant bacteria, food safety issues, and environmental impact, an increasing number of scientific studies have referred to the new therapeutic procedures that could serve as alternatives to conventional therapy. Therefore, the aim of this review was to provide insight into the currently available literature data in the investigation of non-antibiotic alternative approaches. In general, a vast number of in vitro and in vivo available data offer the comprehension of novel, effective, and safe agents with the potential to reduce the current use of antibiotics and increase animal productivity and environmental protection. Constant progress in this field could overcome treatment difficulties associated with bovine mastitis and considerable global pressure being applied on reducing antimicrobial therapy in animals.

19 February 2021 in Antibiotics
Verified
Journal Article
Open access
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ZKZorana Kovacevic
Zorana Kovacevic
MRMiodrag Radinović
Miodrag Radinović
Ivana S. CabarkapaIvana S. Cabarkapa
Ivana S. Cabarkapa
NKNebojša Kladar
Nebojša Kladar
BBBiljana Božin
Biljana Božin
Bovine mastitis is the most widespread and economically important disease worldwide. The present study aimed to determine bioactive compounds in two essential oils (EOs) from wild (Thymus serpyllum) and common thyme (Thymus vulgaris) and to assess the antioxidant potential as well as antibacterial efficacy of the EOs against mastitis-associated bacteria. The study also included antibiotic susceptibility tests. The strains were previously isolated from lactating animals with clinical and subclinical mastitis. The antioxidant potential of the commercial EOs of wild and common thyme was evaluated by five in vitro assays. The antibacterial activity was performed using the microdilution technique, while antibiotic susceptibility testing was performed by the Kirby–Bauer disc diffusion method. The dominant compound in wild thyme was thymol (45.22%), followed by p-cymene (23.83%) and γ-terpinene (3.12%), while in common thyme, it was thymol (54.17%), followed by γ-terpinene (22.18%) and p-cymene (16.66%). Among the fourteen mastitis-associated bacteria, strain IX Streptococcus spp. (β-hemolytic) was the most sensitive to the tested EOs (minimum inhibitory concentration (MIC)/minimal bactericidal concentration (MBC) were 0.78/1.56 and 0.39/0.78 mg/mL for T. serpyllum (TS) and T. vulgaris (TV), respectively). Regarding Streptococcus spp. β heamoliticus, MICs for TS ranged from 0.78 to 1.56 mg/mL, while for the same oil, MBCs ranged from 1.56 to 12.5 mg/mL. In the case of T. vulgaris, MICs ranged from 0.39 to 3.125 mg/ mL, while MBCs ranged from 3.125 to 6.25 mg/mL. TV is more active against E. coli, E. sakazakii, and Streptococcus spp., while it is less effective against Staphylococcus spp. than TS. The study revealed that the tested EOs possess remarkable antioxidative and antibacterial activities and could be used in the development of pharmaceutical formulation as an alternative to conventional mastitis therapy.

6 January 2025 in Antibiotics
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Journal Article
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Olga HorvatOlga Horvat
Olga Horvat
ZKZorana Kovacevic
Zorana Kovacevic
Antimicrobial resistance (AMR) represents a critical threat to human, animal, and environmental health, challenging global efforts to maintain sustainable ecosystems and public health systems. In this review, the complex, cross-disciplinary issues of AMR are explored within the framework of planetary health, emphasizing the interconnectedness of human and veterinary medicine with broader environmental and social systems. Specifically, it addresses the social, economic, environmental, and health dimensions of AMR under the planetary health framework. The social aspects consider how public awareness, education, and healthcare practices shape antimicrobial use (AMU) and resistance patterns. The economic impact evaluates the cost burdens of AMR, including healthcare costs, loss of productivity, and the implications for the livestock and food production industries. The environmental dimension highlights the role of pharmaceutical waste, agricultural runoff, and industrial pollution in contributing to the spread of antimicrobials and resistant pathogens in ecosystems. To illustrate these challenges, a comprehensive literature review using the PubMed and Web of Science databases was conducted, identifying 91 relevant articles on planetary health and AMR. In this review, the knowledge from these studies and additional references is integrated to provide a holistic overview of the AMR crisis. By applying the four pillars of planetary health—social, economic, environmental, and health knowledge—in this manuscript, the necessity is underscored of collaborative strategies across human and veterinary medicine to combat AMR. Ultimately, this synergistic approach aims to shape the policies and practices that safeguard public health, protect ecosystems, and promote a sustainable future by implementing antimicrobial stewardship programs and encouraging prudent AMU.

20 December 2022 in Antibiotics
Verified
Journal Article
Open access
PDF file
ZKZorana Kovacevic
Zorana Kovacevic
MSMarko Samardžija
Marko Samardžija
Olga HorvatOlga Horvat
Olga Horvat
DTDragana Tomanić
Dragana Tomanić
MRMiodrag Radinović
Miodrag Radinović
NKNebojša Kladar
Nebojša Kladar
Antimicrobials have had an important impact on animal health and production performance. However, non-prudent antimicrobial use (AMU) in food producing animals is considered to contribute to the emergence of antimicrobial resistance (AMR), with a potential impact on both animal and public health. Considering the global importance of AMR, and the threats and challenges posed by mastitis and mastitis therapy in livestock production, the main objective of this study was to quantify AMU on three dairy farms in Serbia and to examine whether there is an association between AMU and the emergence of antimicrobial resistance of mastitis-associated pathogens. Antimicrobial susceptibility testing was performed by the disk diffusion method using causative agents isolated from the milk samples of 247 dairy cows. AMU data were obtained for a one-year period (May 2021 to May 2022) based on antibiotic prescriptions listed in electronic databases kept by farm veterinarians. To estimate antimicrobial drug exposure at the farm level, the veterinary drug Defined Daily Dose was calculated by multiplying the total amount of antibiotic used on the farms during the study period by the quantity of antibiotic in the administered drug and number of original drug packages used. The results on the association between the use of common antibiotics in mastitis treatment and AMR of isolated mastitis-associated pathogens confirm a pattern that could raise awareness of the importance of this aspect of good veterinary and clinical practice to combat the global threat of AMR.

22 December 2022 in Antibiotics
Verified
Journal Article
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ZKZorana Kovacevic
Zorana Kovacevic
JMJovan Mihajlović
Jovan Mihajlović
SMSnežana Mugoša
Snežana Mugoša
Olga HorvatOlga Horvat
Olga Horvat
DTDragana Tomanić
Dragana Tomanić
MSMarko Samardžija
Marko Samardžija
Mastitis in dairy cows is responsible for major economic losses on dairy farms worldwide as the most expensive and prevalent disease in dairy cattle. In spite of the fact that antibiotic therapy still remains the main treatment strategy for bovine mastitis, concerns about the shortcomings of this treatment approach are continuously raised. Hence, research on alternative treatments with increased effectiveness and reduced costs is needed. Therefore, we conducted a pharmacoeconomic analysis of conventional antibiotic vs. a proposed Phyto-Bomat treatment based on essential oils in bovine mastitis therapy. Treatments were compared from the farmer’s perspective in the domain of costs (expressed in total, direct and indirect, cost differences) and effectiveness (expressed in daily milk yield differences). Economic calculations were based on data from a dairy farm in Serbia. The average cost of conventional antibiotic treatment was estimated at EUR 80.32 consisting of therapy costs, veterinary services and milk rejection costs at EUR 16.54, EUR 17.68 and EUR 46.10, respectively. The average cost of Phyto-Bomat treatment was estimated at EUR 76.34 with therapy costs of EUR 34.34, veterinary costs of EUR 32.00 and rejection of milk costs of only EUR 10.00. Therefore, Phyto-Bomat results in cost savings approximating EUR 4 per each mastitis episode with the highest cost reductions obtained in milk rejection costs. This estimation of Phyto-Bomat’s economic benefits could be used as a starting point for the inclusion of this formulation as an alternative treatment approach with a focus on subclinical mastitis since it contributes to most of the financial losses.

27 November 2021 in Antibiotics
Verified
Journal Article
Open access
PDF file
ZKZorana Kovacevic
Zorana Kovacevic
NKNebojša Kladar
Nebojša Kladar
Ivana S. CabarkapaIvana S. Cabarkapa
Ivana S. Cabarkapa
MRMiodrag Radinović
Miodrag Radinović
MMMilan Maletić
Milan Maletić
BBBiljana Božin
Biljana Božin
Mastitis represents a heavy burden for the dairy sector worldwide with high economic and animal welfare impact. Antibiotic treatment is an important component of mastitis control programs. However, emergence and transfer of antimicrobial-resistant (AMR) bacteria is becoming a growing concern. Therefore, the development of novel agents is required for prevention and treatment of mastitis. Hence, our aim was to assess the antibacterial properties of two essential oils (EOs) obtained from oregano (Origanum vulgare L., Lamiaceae) and mountain savory (Satureja montana L., Lamiaceae) against mastitis-associated bacteria in Serbia. The chemical composition and antioxidant potential of these EOs were also evaluated. The present study was conducted on strains derived from aseptic milk samples collected from Holstein-Friesian cows with clinical or subclinical mastitis, during the morning milking. Clinical mastitis was assessed by clinical examination, while subclinical mastitis was confirmed using somatic cell count in the milk samples. The microdilution method was used to determine the antibacterial activity, while antioxidant potential of the EOs was evaluated in several in vitro assays. The values of minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) were used to quantitatively measure the antibacterial activity of each EO. MIC/MBC ranged from 0.78/6.25 and 0.39/0.78 mg/mL for oregano and mountain savory, respectively. A total of 25 compounds were identified in the oregano EO, while 47 were identified in winter savory EO, among which aromatic oxygenated monoterpenes were the most abundant compounds. The tested EOs have shown promising antimicrobial activity and could be considered as one of the treatment approaches in mastitis-affected cows.