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Nasal carriage of resistant Staphylococcus aureus in a medical student community
Carolina Y Gushiken1, Liliane B Medeiros1, Bruna P Correia2
1Faculdade de Biomedicina, Universidade do Oeste Paulista/UNOESTE, Rua José Bongiovani, 700, 19050-920 Presidente Prudente, SP, Brasil.
Abstract:
Staphylococcus aureus can cause a variety of infections due to its high transmissibility, high pathogenic potential and resistance to multiple drugs, factors that contribute to the relevance of infections in healthcare services. The aim of this study was to document phenotypic and genotypic resistance factors of Staphylococcus aureus strains, isolated from nasal mucosa of medical students. A nasal swab was collected from the nares (nostrils) of 222 medical students. After collection, the samples were submitted to isolation and identification procedures. From 204 valid samples, 20.6% (42 samples) were positive for S. aureus. For the assessment of phenotypic resistance by disk-diffusion technique, from 42 samples, 95.2% showed resistance to erythromycin, 42.8% to clindamycin, 16.6% to cephoxitin and 9.5% to oxacillin. The D test showed that 26.2% of samples were resistant to macrolides, lincosamides and streptogramin B. A PCR assay allowed for the evaluation of a genotypic resistance profile, in which 16.6% of the samples were positive for the mecA gene, 35.7% positive for the ermC gene or ermA gene and 28.5% were positive for both genes. These results demonstrate that medical students can enter the healthcare service previously colonized by multidrug resistant strains and become potential spreaders in the hospital environment.
Insights
Medical students frequently carry multidrug-resistant Staphylococcus aureus strains in their nasal passages. This colonization poses a significant risk for spreading these resistant bacteria within healthcare settings.
Area of Science:
- Microbiology
- Infectious Diseases
- Medical Education
Background:
- Staphylococcus aureus is a significant pathogen causing various infections.
- Its high transmissibility, pathogenicity, and multidrug resistance (MDR) contribute to healthcare-associated infections.
- Understanding resistance patterns in potential healthcare workers is crucial.
Purpose of the Study:
- To investigate phenotypic and genotypic resistance factors of Staphylococcus aureus.
- To identify S. aureus strains isolated from the nasal mucosa of medical students.
- To assess the prevalence of antibiotic resistance in this population.
Main Methods:
- Nasal swabs collected from 222 medical students.
- Isolation and identification of S. aureus.
- Phenotypic resistance assessed by disk-diffusion and D test.
- Genotypic resistance analyzed using PCR for mecA, ermA, and ermC genes.
Main Results:
- S. aureus identified in 20.6% of samples.
- High rates of phenotypic resistance observed: erythromycin (95.2%), clindamycin (42.8%), cephoxitin (16.6%), oxacillin (9.5%).
- D test indicated 26.2% resistance to macrolides, lincosamides, and streptogramin B; PCR detected mecA (16.6%), erm genes (35.7%), or both (28.5%).
Conclusions:
- Medical students can be colonized with MDR S. aureus strains prior to entering clinical practice.
- These students may act as potential reservoirs and spreaders of resistant bacteria in hospitals.
- Highlights the importance of surveillance and infection control measures among healthcare trainees.
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