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Updated: Jun 25, 2026
Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
Detection of Antimicrobial Resistance of Bacteria Staphylococcus chromogenes Isolated from Sheep's Milk and Cheese
Ivana Regecová1, Jana Výrostková1, František Zigo2
1Department of Food Hygiene, Technology and Safety, The University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, 041 81 Košice, Slovakia.
Abstract:
Antimicrobial and multidrug resistance is detected in nonaureus staphylococci, including Staphylococcus chromogenes, which commonly causes intramammary infections. Recent clinical studies point to the presence of methicillin-resistant S. chromogenes. Therefore, this study aims to determine the prevalence of this species in samples of sheep's milk and cheeses made from them. Isolates were identified by polymerase chain reaction and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). A total of 208 staphylococcal isolates were identified. Of these, 18% were identified as S. chromogenes. The antimicrobial resistance of the identified isolates was determined using the agar dilution method against penicillin, ceftaroline, teicoplanin, gentamicin, erythromycin, tetracycline, and ofloxacin. The highest resistance was found to penicillin (95%), tetracycline (86%), and oxacillin (81%). The highest sensitivity was confirmed for gentamicin (55%). The study also confirmed the presence of methicillin resistant staphylococcal isolates (30%) based on the phenotypic manifestation of antimicrobial resistance and detection of the presence of the mecA gene. The study shows that the tested isolates (62%) were multidrug resistant. Resistance to two antibiotics was most often found (39%).
Insights
Methicillin-resistant Staphylococcus chromogenes, a cause of intramammary infections, was found in sheep
Area of Science:
- Veterinary Microbiology
- Food Safety
- Antimicrobial Resistance
Background:
- Nonaureus staphylococci, including Staphylococcus chromogenes, exhibit antimicrobial and multidrug resistance.
- Staphylococcus chromogenes is a common cause of intramammary infections in livestock.
- Methicillin-resistant Staphylococcus chromogenes (MRSC) has been increasingly detected in clinical settings.
Purpose of the Study:
- To determine the prevalence of Staphylococcus chromogenes in sheep's milk and derived cheeses.
- To investigate the antimicrobial resistance patterns of Staphylococcus chromogenes isolates.
- To identify the presence of methicillin resistance in Staphylococcus chromogenes.
Main Methods:
- Species identification using Polymerase Chain Reaction (PCR) and MALDI-TOF Mass Spectrometry.
- Antimicrobial susceptibility testing via agar dilution method.
- Detection of the mecA gene for methicillin resistance confirmation.
Main Results:
- Staphylococcus chromogenes constituted 18% of 208 staphylococcal isolates from sheep's milk and cheese.
- High resistance rates were observed for penicillin (95%), tetracycline (86%), and oxacillin (81%).
- Thirty percent of isolates were methicillin-resistant, confirmed by the mecA gene, and 62% exhibited multidrug resistance.
Conclusions:
- Staphylococcus chromogenes is prevalent in sheep's milk products, posing potential food safety concerns.
- Significant antimicrobial and multidrug resistance, including methicillin resistance, is present in these isolates.
- Effective monitoring and control strategies are crucial to mitigate the spread of resistant bacteria in dairy production.
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