Nasal carriage of resistant Staphylococcus aureus in a medical student community

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.

Dissemination of macrolides, fusidic acid and mupirocin resistance among Staphylococcus aureus clinical isolates

“…In this study, the resistance rate of erythromycin (73.5%, Table 1 ) was higher than that in Belgium (37.4%) [ 20 ], Iran (42%) [ 21 ] and India (51.7%) [ 22 ], but lower than that in Korean (77.5%) [ 23 ] and Brazil (95.2%) [ 24 ]. Interestingly, compared with two previous reports (97.3% in MSSA, 98% in MRSA and 59.1% in S. aureus ) [ 25 , 26 ] surveyed in China, our study indicated different geographical regions and bacteria sources harbored diverse but increasing erythromycin resistant ratio.…”

“…It is notable that the predominance of these genes (i.g. ermA and ermC ) was variable in several countries [ 4 , 24 , 29 – 31 ]. Here in China we found that, among the 27 macrolide-resistant S. aureus isolates, ermC was the most prevalent resistance determinant and ermA was less prevalent (51.9% vs 11.1%, Table 3 ).…”

Factors associated with Staphylococcus aureus nasal carriage and molecular characteristics among the general population at a Medical College Campus in Guangzhou, South China

“…In addition, the analogous report that the detection rate of S. aureus at Wenzhou Medical College in Wenzhou was 15.4%, of which 3.0% were MRSA [29]. Besides, the study from Brasil reported that in a medical student community, the detection rate of S. aureus and MRSA were 20.6 and 3.4% [30]. In contrast, the detection rate of S. aureus in this study is higher than the analogous report, but the detection rate of MRSA is lower.…”

Molecular characterization of methicillin-resistant and -susceptible Staphylococcus aureus recovered from hospital personnel

“…Cotton swabs (Yangsheng Biotech, PR China) were used to collect samples from anterior nares of hospital personnel. The cotton swab was gently inserted into one of the nostrils up to 1 cm and was rotated three times to sample the inner surfaces [5]. Hand samples were collected using sterile phosphate-buffered saline (PBS) buffer-soaked cotton swabs.…”