Antibiotic resistance and biofilm formation in <i>Staphylococcus aureus</i> isolated from dairy cows at the stage of subclinical mastitis in northern Kazakhstan
<p><i>Staphylococcus aureus</i> is an important causative agent of subclinical bovine mastitis worldwide. The aim of this research was to study the ability of <i>S. aureus</i> to form biofilms. Additionally, we examined the genes involved in cell resistance and sensitiv...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-12-01
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| Series: | Archives Animal Breeding |
| Online Access: | https://aab.copernicus.org/articles/65/439/2022/aab-65-439-2022.pdf |
| Summary: | <p><i>Staphylococcus aureus</i> is an important causative agent of subclinical bovine mastitis worldwide.
The aim of this research was to study the ability of <i>S. aureus</i> to form biofilms.
Additionally, we examined the genes involved in cell resistance and
sensitivity to antibiotics. Samples were collected from December 2020 to May
2021 from Simmental and black-and-white cows. The study was carried out on a
total number of 643 cows, of which 278 (23 %) were in the subclinical
mastitis stage. Finally, 64 <i>S. aureus</i> isolates were isolated and identified. The
highest level of phenotypic resistance was observed to antibiotics of the
tetracycline (tetracycline – 48.4 %, doxycycline – 32.8 %) and
<span class="inline-formula"><i>β</i></span>-lactam (ampicillin – 45.3 %, penicillin – 45.3 %) groups. The
genes encoding antibiotic resistance were characterized with the polymerase
chain reaction method: <i>blaZ</i> in 30 isolates, <i>mecA</i> in 1 isolate, <i>ermC</i> in 15 isolates, <i>aph</i> (3) in 2 isolates, <i>tetK</i> in 19 isolates, <i>tetM</i> in 9 isolates.
The tested <i>S. aureus</i> isolates had the ability to form biofilms in 76.6 % (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">49</mn><mo>/</mo><mn mathvariant="normal">64</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="33pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e56b8be3867ed9d1167b8c09b8e829a6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="aab-65-439-2022-ie00001.svg" width="33pt" height="14pt" src="aab-65-439-2022-ie00001.png"/></svg:svg></span></span>) of
cases. Of these, 69.4 % were resistant to at least one antibiotic. The
obtained results have shown that <i>S. aureus</i>, identified in cows with subclinical
mastitis, was resistant mainly to tetracycline and <span class="inline-formula"><i>β</i></span>-lactam antibiotics.
In addition, <i>S. aureus</i> isolates expressed resistance genes to the above drugs and had
the ability to form biofilm. This study will help to identify the
extent of antibiotic resistance and monitor <i>S. aureus</i> contamination of raw milk.</p> |
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| ISSN: | 0003-9438 2363-9822 |