Hospital clones of methicillin-resistant Staphylococcus aureus are carried by medical students even before healthcare exposure

Abstract

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) strains are prevalent in healthcare and the community. Few studies have examined MRSA carriage among medical students.The aim of this study is to examine Staphylococcus aureus (SA) carriage, and particular MRSA, over time in cohort medical studentsMethodsProspective collection of nasal swabs from medical students in Israel and assessment of SA carriage. Three samples were taken per student in preclinical and clinical parts of studies. Antibiotic susceptibilities were recorded and MRSA typing was performed by staphylococcal cassette chromosome mec (SCCmec) types, Panton Valentine Leukocidin (PVL) encoding genes, and spa types. Clonality was assessed by pulsed-field gel electrophoresis.ResultsAmong 58 students, SA carriage rates increased from 33% to 38% to 41% at baseline (preclinical studies), 13 and 19 months (clinical studies), respectively (p = 0.07). Methicillin-susceptible SA (MSSA) carriage increased in the clinical studies period (22 to 41%, p = 0.01). Overall, seven students (12%) carried 13 MRSA isolates. MRSA isolates were PVL negative and were characterized as SCCmecII-t002, SCCmecIV-t032, or t12435 with untypable SCCmec. MRSA carriage during the pre-clinical studies was evident in 4/7 students. Two students carried different MRSA clones at various times and persistent MRSA carriage was noted in one student. Simultaneous carriage of MRSA and MSSA was not detected.ConclusionsMSSA carriage increased during the clinical part of studies in Israeli medical students. Compared with previous reports, higher rates of MRSA carriage were evident. MRSA strains were genotypically similar to Israeli healthcare-associated clones; however, carriage occurred largely before healthcare exposure, implying community-acquisition of hospital strains.

Nasal colonization by methicillin-sensitive and methicillin-resistant Staphylococcus aureus among medical students

“…MRSA is regarded as the most serious infection in hospitals [42]. Although medical students are not considered part of medical staff in hospitals, they interact frequently with patients during their training and play an important role for causing and transmitting nosocomial infections [30][31][32]34,35].…”

“…Investigating the role of medical students as nasal carriers of MRSA has attained recent interest as medical students constitute an important but forgotten part of the healthcare workforce that interacts frequently with patients and are less informed and possibly not well trained about infection control measures [29]. Several previous studies have investigated the prevalence of MRSA carriers among medical students [30][31][32][33] which proved their important role in nosocomial infections [34,35]. The main aim of the present study was to investigate the prevalence, antimicrobial susceptibility pattern, antibiotics resistance genes, and risk factors of MRSA-carrying medical students in Jordan.…”

Characterization of resistance to selected antibiotics and Panton-Valentine leukocidin-positive Staphylococcus aureus in a healthy student population at a Malaysian University

“…2 The proportion of MRSA carriage in our collection was in concordance with other worldwide studies investigating the prevalence of MRSA carriage that varied within 0.34 to 12% rates in medical students and healthcare centres. 2,3,22 Among the four MRSA strains, three isolates were detected as SCCmec I and one isolate was identified as SCCmec III. Although the number of MRSA in this study is low, the predominant occurrence of SCCmec I from this study is consistent with a previous study in a similar setting by Mat Azis et al, indicating the persistency of MRSA with SCCmec I.…”

Nasal Methicillin-resistant Staphylococcus aureus carriage and related risk factors in university student population

“…S. aureus nasal carriage rates remarkably vary among different populations; however, our rates are comparable with other reports with similar study samples [16][17][18] . Studies focusing on university students have reported MRSA prevalence in a range between 1.5% and 13% [18][19][20][21][22] . Most studies have investigated medical students, which are characteristically a narrower population with low MRSA carriage rates [18,19] .…”