INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024)
The aim of the present study was to investigate the prevalence of resistance to several groups of antibiotics among commensal Escherichia coli bacteria isolated from broilers in Bulgaria. Between March 2020 and September 2024, a total of 510 cloacal swab samples were obtained from broilers on two p...
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Scientific Veterinary Institute “Novi Sad”
2025-06-01
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| Series: | Archives of Veterinary Medicine |
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| Online Access: | https://niv.ns.ac.rs/e-avm/index.php/e-avm/article/view/461 |
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| author | Valentina Urumova Radostina Stefanova Dima Dobreva |
| author_facet | Valentina Urumova Radostina Stefanova Dima Dobreva |
| author_sort | Valentina Urumova |
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The aim of the present study was to investigate the prevalence of resistance to several groups of antibiotics among commensal Escherichia coli bacteria isolated from broilers in Bulgaria. Between March 2020 and September 2024, a total of 510 cloacal swab samples were obtained from broilers on two poultry farms, one located in central Bulgaria and the other in the northern region of the country. Of the collected samples, 90 were taken from one-day-old broilers, 140 from 14-day-old broilers, and 280 from broilers aged 28 to 30 days. The total number of Escherichia coli isolates was 479, 89 of which from one-day-old broilers, 126 from 14-day-old and 264 from 28-30-day-old broilers. In addition, 12 samples were obtained from poultry litter, from which 10 Escherichia coli strains were isolated. The highest rates of resistance among commensal Escherichia coli from day-old birds were observed against ampicillin (49.4%), tetracycline (43.8%), followed by amoxicillin/clavulanic acid (34.8%). The strains resistant to the third-generation cephalosporins cefotaxime and ceftazidime were 7.9% and 3.4% respectively. The most prevalent resistance phenotype among the strains included resistance to aminopenicillins and tetracycline (28.1%), with the tetA gene being the most frequently detected (7.8%). The highest resistance rates were against ciprofloxacin (73.8%) in strains from 14-day-old broilers, while the highest resistance rate in isolates from 28-30-day-old birds was against ampicillin (65.6%). Tetracycline-resistant strains were 69.0% and 60.6%, respectively. The phenotypic profile including resistance to beta-lactams, tetracycline and ciprofloxacin predominated among 28.8% of the strains from both groups of broilers, with the highest prevalence for the tetA (26.4%) and qnrS (15.1%) genes. In the resistant strains isolated from poultry litter, the highest resistance rates were against ampicillin (100%), followed by tetracycline (80%), amoxicillin/clavulanic acid (70%) and ciprofloxacin (60%).
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| format | Article |
| id | doaj-art-0d565334f0124c8aa30143695aedd56f |
| institution | OA Journals |
| issn | 1820-9955 2683-4138 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Scientific Veterinary Institute “Novi Sad” |
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| spelling | doaj-art-0d565334f0124c8aa30143695aedd56f2025-08-20T02:05:29ZengScientific Veterinary Institute “Novi Sad”Archives of Veterinary Medicine1820-99552683-41382025-06-0118110.46784/e-avm.v18i1.461INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024)Valentina Urumova0Radostina Stefanova1Dima Dobreva2Trakia University, Faculty of Veterinary medicineTrakia University, Faculty of Veterinary medicine, Department of Veterinary microbiology, Infectious and Parasitic Diseases, Stara ZagoraTrakia University, Faculty of Veterinary medicine, Department of Veterinary microbiology, Infectious and Parasitic Diseases, Stara Zagora The aim of the present study was to investigate the prevalence of resistance to several groups of antibiotics among commensal Escherichia coli bacteria isolated from broilers in Bulgaria. Between March 2020 and September 2024, a total of 510 cloacal swab samples were obtained from broilers on two poultry farms, one located in central Bulgaria and the other in the northern region of the country. Of the collected samples, 90 were taken from one-day-old broilers, 140 from 14-day-old broilers, and 280 from broilers aged 28 to 30 days. The total number of Escherichia coli isolates was 479, 89 of which from one-day-old broilers, 126 from 14-day-old and 264 from 28-30-day-old broilers. In addition, 12 samples were obtained from poultry litter, from which 10 Escherichia coli strains were isolated. The highest rates of resistance among commensal Escherichia coli from day-old birds were observed against ampicillin (49.4%), tetracycline (43.8%), followed by amoxicillin/clavulanic acid (34.8%). The strains resistant to the third-generation cephalosporins cefotaxime and ceftazidime were 7.9% and 3.4% respectively. The most prevalent resistance phenotype among the strains included resistance to aminopenicillins and tetracycline (28.1%), with the tetA gene being the most frequently detected (7.8%). The highest resistance rates were against ciprofloxacin (73.8%) in strains from 14-day-old broilers, while the highest resistance rate in isolates from 28-30-day-old birds was against ampicillin (65.6%). Tetracycline-resistant strains were 69.0% and 60.6%, respectively. The phenotypic profile including resistance to beta-lactams, tetracycline and ciprofloxacin predominated among 28.8% of the strains from both groups of broilers, with the highest prevalence for the tetA (26.4%) and qnrS (15.1%) genes. In the resistant strains isolated from poultry litter, the highest resistance rates were against ampicillin (100%), followed by tetracycline (80%), amoxicillin/clavulanic acid (70%) and ciprofloxacin (60%). https://niv.ns.ac.rs/e-avm/index.php/e-avm/article/view/461poultryresistanceantimicrobiall agentscommensal Escherichia coli |
| spellingShingle | Valentina Urumova Radostina Stefanova Dima Dobreva INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) Archives of Veterinary Medicine poultry resistance antimicrobiall agents commensal Escherichia coli |
| title | INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) |
| title_full | INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) |
| title_fullStr | INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) |
| title_full_unstemmed | INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) |
| title_short | INVESTIGATION ON ANTIMICROBIAL RESISTANCE RATES IN COMMENSAL ESCHERICHIA COLI ISOLATES FROM BROILERS ORIGINATING FROM BULGARIA (2020-2024) |
| title_sort | investigation on antimicrobial resistance rates in commensal escherichia coli isolates from broilers originating from bulgaria 2020 2024 |
| topic | poultry resistance antimicrobiall agents commensal Escherichia coli |
| url | https://niv.ns.ac.rs/e-avm/index.php/e-avm/article/view/461 |
| work_keys_str_mv | AT valentinaurumova investigationonantimicrobialresistanceratesincommensalescherichiacoliisolatesfrombroilersoriginatingfrombulgaria20202024 AT radostinastefanova investigationonantimicrobialresistanceratesincommensalescherichiacoliisolatesfrombroilersoriginatingfrombulgaria20202024 AT dimadobreva investigationonantimicrobialresistanceratesincommensalescherichiacoliisolatesfrombroilersoriginatingfrombulgaria20202024 |