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Published on: February 19, 2019
Macrolide-Lincosamide Resistance and Virulence Genes in Staphylococcus aureus Isolated from Clinical Specimens in
Meysam Manouchehrifar1, Farzad Khademi1, Hadi Peeri Doghaheh1
1Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran.
Background & Objective:
Staphylococcus aureus causes various hospital- and community-acquired infections. This study aimed to investigate the phenotypic and genotypic characteristics of erythromycin and inducible clindamycin resistance, virulence gene profiles, and spa types of S. aureus isolates collected from patients in Ardabil Province, Iran.
Methods:
A total of 118 clinical S. aureus isolates, including 50 (42.4%) methicillin-resistant S. aureus (MRSA) and 68 (57.6%) methicillin-susceptible S. aureus (MSSA) strains, were investigated. Resistance patterns were determined by the disk diffusion method and minimum inhibitory concentration (MIC) test. Inducible macrolide-lincosamide-streptogramin B (iMLSB) resistance was detected using D-test method. The polymerase chain reaction (PCR) was used to identify the virulence and resistance-encoding genes. Additionally, the spa types of the isolates were determined using the PCR, followed by sequencing.
Results:
In total, 49.1% (58/118) and 44% (52/118) of the isolates were resistant to erythromycin and clindamycin, respectively. Overall, 13.5% (16/118) of the isolates showed the iMLSB resistance phenotype. The ermC gene (72.4% [42]) was the most frequent erythromycin resistance-encoding gene, followed by ermA (60.3% [35]), ermB (60.3% [35]), ermTR (51.7% [30]), and msrA (15.5% [9]) genes among erythromycin-resistant isolates. The virulence genes hla, hld, sea, LukS PV, tst, seb, sed, eta, sec, and etb were detected in 93.2%, 74.5%, 70.3%, 32.2%, 29.6%, 17%, 8.5%, 8.5%, 5.9%, and 4.2% of the isolates, respectively. Ten different spa types were identified for 58 erythromycin-resistant S. aureus strains, of which t030 and t078 types were the most common types.
Conclusion:
A high frequency of macrolide- and lincosamide-resistant S. aureus isolates with different genetic backgrounds of resistance and virulence may be found in patients in Ardabil Province, Iran.
Insights
This study found high rates of erythromycin and clindamycin resistance in Staphylococcus aureus isolates from Iran. Key resistance genes and virulence factors were identified, highlighting the need for surveillance.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Staphylococcus aureus is a significant cause of hospital and community infections.
- Understanding antibiotic resistance patterns and virulence factors is crucial for effective treatment and control.
Purpose of the Study:
- To investigate phenotypic and genotypic characteristics of erythromycin and inducible clindamycin resistance in S. aureus.
- To profile virulence genes and spa types of S. aureus isolates from Ardabil Province, Iran.
Main Methods:
- 118 clinical S. aureus isolates (MRSA and MSSA) were analyzed.
- Disk diffusion, MIC, D-test, and PCR were used to determine resistance, virulence genes, and spa types.
Main Results:
- 49.1% and 44% of isolates were resistant to erythromycin and clindamycin, respectively.
- The ermC gene was most frequent among erythromycin-resistant isolates. Various virulence genes were detected.
- Ten spa types were identified, with t030 and t078 being most common.
Conclusions:
- A high prevalence of macrolide- and lincosamide-resistant S. aureus was observed.
- Diverse genetic backgrounds of resistance and virulence were present in isolates from Ardabil Province, Iran.
