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Comparative molecular analysis of erythromycin-resistance determinants in staphylococcal isolates of poultry and
M S Nawaz1, S A Khan, A A Khan
1Division of Microbiology, National Center for Toxicological Research/FDA, 3900 NCTR Road, Jefferson, AR 72079, USA. mnawaz@nctr.fda.gov
Abstract:
The ermA, ermB, ermC and msrA/msrB genes were detected in multidrug-resistant Staphylococcus spp. strains by PCR. Among 25 human clinical staphylococcal isolates the ermA, ermB, ermC and the msrA/msrB genes were detected in 88, 72, 4 and 100% of the strains, respectively. Among 24 poultry isolates the ermA, ermB, ermC and the msrA/msrB genes were detected in 100, 16.6, 50 and 12.5% of the strains, respectively. The ermA gene was found exclusively on the chromosome, whereas the ermC gene was found on 2.4-4.2 kb plasmids. Restriction fragment length polymorphism (RFLP) analysis of the ermA gene with Eco RI revealed five patterns (25.0, 21.0, 10.5, 6.2 and 4. 8 kb) for the clinical strains and two (8.0 and 6.2 kb) for the poultry strains. The 6.2 kb RFLP pattern, in both the poultry and human clinical isolates, indicates a common lineage for the ermA gene.
Insights
Multidrug-resistant Staphylococcus strains carry ermA, ermB, ermC, and msrA/msrB genes. A shared 6.2 kb RFLP pattern for the ermA gene in human and poultry isolates suggests a common origin.
Area of Science:
- Microbiology
- Genetics
- Antimicrobial Resistance
Background:
- Multidrug-resistant Staphylococcus species pose a significant threat to public health.
- Understanding the genetic basis of this resistance is crucial for developing effective treatment strategies.
Purpose of the Study:
- To investigate the prevalence and genetic characteristics of specific antibiotic resistance genes (ermA, ermB, ermC, msrA/msrB) in multidrug-resistant Staphylococcus strains.
- To determine the genetic relatedness of these genes between human clinical and poultry isolates.
Main Methods:
- Polymerase Chain Reaction (PCR) was used to detect the presence of ermA, ermB, ermC, and msrA/msrB genes.
- Restriction Fragment Length Polymorphism (RFLP) analysis with EcoRI was performed on the ermA gene to assess genetic diversity and relatedness.
Main Results:
- High prevalence of ermA (88% human, 100% poultry) and msrA/msrB (100% human, 12.5% poultry) genes was observed in clinical and poultry isolates, respectively.
- The ermA gene was located on the chromosome, while ermC was found on plasmids (2.4-4.2 kb).
- A common 6.2 kb RFLP pattern for the ermA gene was identified in both human and poultry isolates, indicating a shared lineage.
Conclusions:
- The study highlights the widespread presence of key macrolide resistance genes in multidrug-resistant Staphylococcus.
- The findings suggest a potential common genetic origin or transmission pathway for the ermA gene between human and poultry populations.